1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
|
<?xml version="1.0" encoding="utf-8"?>
<fields>
<h1>Introduction</h1>
<p>
This document aims to comprehensively document all of the fields,
both standard and non-standard, supported by OpenFlow or Open
vSwitch, regardless of origin.
</p>
<h2>Fields</h2>
<p>
A <dfn>field</dfn> is a property of a packet. Most familiarly, <dfn>data
fields</dfn> are fields that can be extracted from a packet. Most data
fields are copied directly from protocol headers, e.g. at layer 2, the
Ethernet source and destination addresses, or the VLAN ID; at layer 3, the
IPv4 or IPv6 source and destination; and at layer 4, the TCP or UDP ports.
Other data fields are computed, e.g. <ref field="ip_frag"/> describes
whether a packet is a fragment but it is not copied directly from the IP
header.
</p>
<p>
Some data fields, called <dfn>root fields</dfn>, are always present as a
consequence of the basic networking technology in use. The Ethernet header
fields are root fields in current versions of Open vSwitch, though future
versions might support other roots. (Currently, to support LISP tunnels,
which do not encapsulate an Ethernet header, Open vSwitch synthesizes one.)
</p>
<!-- future directions: EXT-112 -->
<p>
Other data fields are not always present. A packet contains ARP fields,
for example, only when its Ethernet header indicates the Ethertype for ARP,
0x0806. In this documentation, we say that a field is
<dfn>applicable</dfn> when it is present in a packet, and
<dfn>inapplicable</dfn> when it is not. (These are not standard terms.)
We refer to the conditions that determine whether a field is applicable as
<dfn>prerequisites</dfn>. Some VLAN-related fields are a special case:
these fields are always applicable, but have a designated value or bit that
indicates whether a VLAN header is present, with the remaining values or
bits indicating the VLAN header's content (if it is present). <!-- XXX
also ethertype -->
</p>
<p>
An inapplicable field does not have a value, not even a nominal
``value'' such as all-zero-bits. In many circumstances, OpenFlow
and Open vSwitch allow references only to applicable fields. For
example, one may match (see <cite>Matching</cite>, below) a given
field only if the match includes the field's prerequisite,
e.g. matching an ARP field is only allowed if one also matches on
Ethertype 0x0806.
</p>
<p>
Sometimes a packet may contain multiple instances of a header.
For example, a packet may contain multiple VLAN or MPLS headers,
and tunnels can cause any data field to recur. OpenFlow and Open
vSwitch do not address these cases uniformly. For VLAN and MPLS
headers, only the outermost header is accessible, so that inner
headers may be accessed only by ``popping'' (removing) the outer
header. (Open vSwitch supports only a single VLAN header in any
case.) For tunnels, e.g. GRE or VXLAN, the outer header and inner
headers are treated as different data fields.
</p>
<p>
Many network protocols are built in layers as a stack of concatenated
headers. Each header typically contains a ``next type'' field that
indicates the type of the protocol header that follows, e.g. Ethernet
contains an Ethertype and IPv4 contains a IP protocol type. The
exceptional cases, where protocols are layered but an outer layer does not
indicate the protocol type for the inner layer, or gives only an ambiguous
indication, are troublesome. An MPLS header, for example, only indicates
whether another MPLS header or some other protocol follows, and in the
latter case the inner protocol must be known from the context. In these
exceptional cases, OpenFlow and Open vSwitch cannot provide insight into
the inner protocol data fields without additional context, and thus they
treat all later data fields as inapplicable until an OpenFlow action
explicitly specifies what protocol follows. In the case of MPLS, the
OpenFlow ``pop MPLS'' action that removes the last MPLS header from a
packet provides this context, as the Ethertype of the payload. See
<cite>Layer 2.5: MPLS</cite> for more information.
</p>
<p>
OpenFlow and Open vSwitch support some fields other than data
fields. <dfn>Metadata fields</dfn> relate to the origin or
treatment of a packet, but they are not extracted from the packet
data itself. One example is the physical port on which a packet
arrived at the switch. <dfn>Register fields</dfn> act like
variables: they give an OpenFlow switch space for temporary
storage while processing a packet. Existing metadata and register
fields have no prerequisites.
</p>
<p>
A field's value consists of an integral number of bytes. For data
fields, sometimes those bytes are taken directly from the packet.
Other data fields are copied from a packet with padding (usually
with zeros and in the most significant positions). The remaining
data fields are transformed in other ways as they are copied from
the packets, to make them more useful for matching.
</p>
<h2>Matching</h2>
<p>
The most important use of fields in OpenFlow is
<dfn>matching</dfn>, to determine whether particular field values
agree with a set of constraints called a <dfn>match</dfn>. A
match consists of zero or more constraints on individual fields,
all of which must be met to satisfy the match. (A match that
contains no constraints is always satisfied.) OpenFlow and Open
vSwitch support a number of forms of matching on individual
fields:
</p>
<dl>
<dt><dfn>Exact match</dfn>, e.g. <code>nw_src=10.1.2.3</code></dt>
<dd>
<p>
Only a particular value of the field is matched; for example, only one
particular source IP address. Exact matches are written as
<code><var>field</var>=<var>value</var></code>. The forms accepted for
<var>value</var> depend on the field.
</p>
<p>
All fields support exact matches.
</p>
</dd>
<dt>
<dfn>Bitwise match</dfn>, e.g. <code>nw_src=10.1.0.0/255.255.0.0</code>
</dt>
<dd>
<p>
Specific bits in the field must have specified values; for example,
only source IP addresses in a particular subnet. Bitwise matches are
written as
<code><var>field</var>=<var>value</var>/<var>mask</var></code>, where
<var>value</var> and <var>mask</var> take one of the forms accepted for
an exact match on <var>field</var>. Some fields accept other forms for
bitwise matches; for example, <code>nw_src=10.1.0.0/255.255.0.0</code>
may also be written <code>nw_src=10.1.0.0/16</code>.
</p>
<p>
Most OpenFlow switches do not allow every bitwise matching on every
field (and before OpenFlow 1.2, the protocol did not even provide for
the possibility for most fields). Even switches that do allow bitwise
matching on a given field may restrict the masks that are allowed, e.g.
by allowing matches only on contiguous sets of bits starting from the
most significant bit, that is, ``CIDR'' masks [RFC 4632]. Open vSwitch
does not allows bitwise matching on every field, but it allows
arbitrary bitwise masks on any field that does support bitwise
matching. (Older versions had some restrictions, as documented in the
descriptions of individual fields.)
</p>
</dd>
<dt><dfn>Wildcard</dfn>, e.g. ``any <code>nw_src</code>''</dt>
<dd>
<p>
The value of the field is not constrained. Wildcarded fields may be
written as <code><var>field</var>=*</code>, although it is unusual to
mention them at all. (When specifying a wildcard explicitly in a
command invocation, be sure to using quoting to protect against shell
expansion.)
</p>
<p>
There is a tiny difference between wildcarding a field and not
specifying any match on a field: wildcarding a field requires
satisfying the field's prerequisites.
</p>
</dd>
</dl>
<p>
Some types of matches on individual fields cannot be expressed directly
with OpenFlow and Open vSwitch. These can be expressed indirectly:
</p>
<dl>
<dt><dfn>Set match</dfn>, e.g. ``<code>tcp_dst</code> ∈ {80, 443,
8080}''</dt>
<dd>
<p>
The value of a field is one of a specified set of values; for
example, the TCP destination port is 80, 443, or 8080.
</p>
<p>
For matches used in flows (see <cite>Flows</cite>, below), multiple
flows can simulate set matches.
</p>
</dd>
<dt><dfn>Range match</dfn>, e.g. ``1000 ≤ <code>tcp_dst</code> ≤
1999''</dt>
<dd>
<p>
The value of the field must lie within a numerical range, for
example, TCP destination ports between 1000 and 1999.
</p>
<p>
Range matches can be expressed as a collection of bitwise matches. For
example, suppose that the goal is to match TCP source ports 1000 to
1999, inclusive. The binary representations of 1000 and 1999 are:
</p>
<pre fixed="yes">
01111101000
11111001111
</pre>
<p>
The following series of bitwise matches will match 1000 and
1999 and all the values in between:
</p>
<pre fixed="yes">
01111101xxx
0111111xxxx
10xxxxxxxxx
110xxxxxxxx
1110xxxxxxx
11110xxxxxx
1111100xxxx
</pre>
<p>
which can be written as the following matches:
</p>
<pre>
tcp,tp_src=0x03e8/0xfff8
tcp,tp_src=0x03f0/0xfff0
tcp,tp_src=0x0400/0xfe00
tcp,tp_src=0x0600/0xff00
tcp,tp_src=0x0700/0xff80
tcp,tp_src=0x0780/0xffc0
tcp,tp_src=0x07c0/0xfff0
</pre>
</dd>
<dt><dfn>Inequality match</dfn>, e.g. ``<code>tcp_dst</code> ≠80''</dt>
<dd>
<p>
The value of the field differs from a specified value, for
example, all TCP destination ports except 80.
</p>
<p>
An inequality match on an <var>n</var>-bit field can be expressed as a
disjunction of <var>n</var> 1-bit matches. For example, the inequality
match ``<code>vlan_pcp</code> ≠5'' can be expressed as
``<code>vlan_pcp</code> = 0/4 or <code>vlan_pcp</code> = 2/2 or
<code>vlan_pcp</code> = 0/1.'' For matches used in flows (see
<cite>Flows</cite>, below), sometimes one can more compactly express
inequality as a higher-priority flow that matches the exceptional case
paired with a lower-priority flow that matches the general case.
</p>
<p>
Alternatively, an inequality match may be converted to a pair of range
matches, e.g. <code>tcp_src ≠80</code> may be expressed as ``0 ≤
<code>tcp_src</code> < 80 or 80 < <code>tcp_src</code> ≤ 65535'',
and then each range match may in turn be converted to a bitwise match.
</p>
</dd>
<dt><dfn>Conjunctive match</dfn>, e.g. ``<code>tcp_src</code> ∈ {80, 443, 8080} and <code>tcp_dst</code> ∈ {80, 443, 8080}''</dt>
<dd>
As an OpenFlow extension, Open vSwitch supports matching on conditions on
conjunctions of the previously mentioned forms of matching. See the
documentation for <ref field="conj_id"/> for more information.
</dd>
</dl>
<p>
All of these supported forms of matching are special cases of bitwise
matching. In some cases this influences the design of field values. <ref
field="ip_frag"/> is the most prominent example: it is designed to make all
of the practically useful checks for IP fragmentation possible as a single
bitwise match.
</p>
<h3>Shorthands</h3>
<p>
Some matches are very commonly used, so Open vSwitch accepts shorthand
notations. In some cases, Open vSwitch also uses shorthand notations when
it displays matches. The following shorthands are defined, with their long
forms shown on the right side:
</p>
<dl>
<dt><code>ip</code></dt> <dd><code>eth_type=0x0800</code></dd>
<dt><code>ipv6</code></dt> <dd><code>eth_type=0x86dd</code></dd>
<dt><code>icmp</code></dt> <dd><code>eth_type=0x0800,ip_proto=1</code></dd>
<dt><code>icmp6</code></dt> <dd><code>eth_type=0x86dd,ip_proto=58</code></dd>
<dt><code>tcp</code></dt> <dd><code>eth_type=0x0800,ip_proto=6</code></dd>
<dt><code>tcp6</code></dt> <dd><code>eth_type=0x86dd,ip_proto=6</code></dd>
<dt><code>udp</code></dt> <dd><code>eth_type=0x0800,ip_proto=17</code></dd>
<dt><code>udp6</code></dt> <dd><code>eth_type=0x86dd,ip_proto=17</code></dd>
<dt><code>sctp</code></dt> <dd><code>eth_type=0x0800,ip_proto=132</code></dd>
<dt><code>sctp6</code></dt> <dd><code>eth_type=0x86dd,ip_proto=132</code></dd>
<dt><code>arp</code></dt> <dd><code>eth_type=0x0806</code></dd>
<dt><code>rarp</code></dt> <dd><code>eth_type=0x8035</code></dd>
<dt><code>mpls</code></dt> <dd><code>eth_type=0x8847</code></dd>
<dt><code>mplsm</code></dt> <dd><code>eth_type=0x8848</code></dd>
</dl>
<h2>Evolution of OpenFlow Fields</h2>
<p>
The discussion so far applies to all OpenFlow and Open vSwitch
versions. This section starts to draw in specific information by
explaining, in broad terms, the treatment of fields and matches in
each OpenFlow version.
</p>
<h3>OpenFlow 1.0</h3>
<p>
OpenFlow 1.0 defined the OpenFlow protocol format of a match as a
fixed-length data structure that could match on the following
fields:
</p>
<ul>
<li>Ingress port.</li>
<li>Ethernet source and destination MAC.</li>
<li>Ethertype (with a special value to match frames that lack an
Ethertype).</li>
<li>VLAN ID and priority.</li>
<li>IPv4 source, destination, protocol, and DSCP.</li>
<li>TCP source and destination port.</li>
<li>UDP source and destination port.</li>
<li>ICMPv4 type and code.</li>
<li>ARP IPv4 addresses (SPA and TPA) and opcode.</li>
</ul>
<p>
Each supported field corresponded to some member of the data
structure. Some members represented multiple fields, in the case
of the TCP, UDP, ICMPv4, and ARP fields whose presence is mutually
exclusive. This also meant that some members were poor fits for
their fields: only the low 8 bits of the 16-bit ARP opcode could
be represented, and the ICMPv4 type and code were padded with 8 bits
of zeros to fit in the 16-bit members primarily meant for TCP and
UDP ports. An additional bitmap member indicated, for each
member, whether its field should be an ``exact'' or ``wildcarded''
match (see <cite>Matching</cite>), with additional support for
CIDR prefix matching on the IPv4 source and destination fields.
</p>
<p>
Simplicity was recognized early on as the main virtue of this
approach. Obviously, any fixed-length data structure cannot
support matching new protocols that do not fit. There was no
room, for example, for matching IPv6 fields, which was not a
priority at the time. Lack of room to support matching the
Ethernet addresses inside ARP packets actually caused more of a
design problem later, leading to an Open vSwitch extension action
specialized for dropping ``spoofed'' ARP packets in which the
frame and ARP Ethernet source addressed differed. (This extension
was never standardized. Open vSwitch dropped support for it a few
releases after it added support for full ARP matching.)
</p>
<p>
The design of the OpenFlow fixed-length matches also illustrates
compromises, in both directions, between the strengths and
weaknesses of software and hardware that have always influenced
the design of OpenFlow. Support for matching ARP fields that do
fit in the data structure was only added late in the design
process (and remained optional in OpenFlow 1.0), for example,
because common switch ASICs did not support matching these fields.
</p>
<p>
The compromises in favor of software occurred for more complicated
reasons. The OpenFlow designers did not know how to implement
matching in software that was fast, dynamic, and general. (A way
was later found [Srinivasan].) Thus, the designers sought to
support dynamic, general matching that would be fast in realistic
special cases, in particular when all of the matches were
<dfn>microflows</dfn>, that is, matches that specify every field
present in a packet, because such matches can be implemented as a
single hash table lookup. Contemporary research supported the
feasibility of this approach: the number of microflows in a campus
network had been measured to peak at about 10,000 [Casado, section
3.2]. (Calculations show that this can only be true in a lightly
loaded network [Pepelnjak].)
</p>
<p>
As a result, OpenFlow 1.0 required switches to treat microflow
matches as the highest possible priority. This let software
switches perform the microflow hash table lookup first. Only on
failure to match a microflow did the switch need to fall back to
checking the more general and presumed slower matches. Also, the
OpenFlow 1.0 flow match was minimally flexible, with no support
for general bitwise matching, partly on the basis that this seemed
more likely amenable to relatively efficient software
implementation. (CIDR masking for IPv4 addresses was added
relatively late in the OpenFlow 1.0 design process.)
</p>
<p>
Microflow matching was later discovered to aid some hardware
implementations. The TCAM chips used for matching in hardware do
not support priority in the same way as OpenFlow but instead tie
priority to ordering [Pagiamtzis]. Thus, adding a new match with
a priority between the priorities of existing matches can require
reordering an arbitrary number of TCAM entries. On the other
hand, when microflows are highest priority, they can be managed as
a set-aside portion of the TCAM entries.
</p>
<p>
The emphasis on matching microflows also led designers to
carefully consider the bandwidth requirements between switch and
controller: to maximize the number of microflow setups per second,
one must minimize the size of each flow's description. This
favored the fixed-length format in use, because it expressed
common TCP and UDP microflows in fewer bytes than more flexible
``type-length-value'' (TLV) formats. (Early versions of OpenFlow
also avoided TLVs in general to head off protocol fragmentation.)
</p>
<h4>Inapplicable Fields</h4>
<p>
OpenFlow 1.0 does not clearly specify how to treat inapplicable
fields. The members for inapplicable fields are always present in
the match data structure, as are the bits that indicate whether
the fields are matched, and the ``correct'' member and bit values
for inapplicable fields is unclear. OpenFlow 1.0 implementations
changed their behavior over time as priorities shifted. The early
OpenFlow reference implementation, motivated to make every flow a
microflow to enable hashing, treated inapplicable fields as exact
matches on a value of 0. Initially, this behavior was implemented
in the reference controller only.
</p>
<p>
Later, the reference switch was also changed to actually force any
wildcarded inapplicable fields into exact matches on 0. The
latter behavior sometimes caused problems, because the modified
flow was the one reported back to the controller later when it
queried the flow table, and the modifications sometimes meant that
the controller could not properly recognize the flow that it had
added. In retrospect, perhaps this problem should have alerted
the designers to a design error, but the ability to use a single
hash table was held to be more important than almost every other
consideration at the time.
</p>
<p>
When more flexible match formats were introduced much later, they
disallowed any mention of inapplicable fields as part of a match.
This raised the question of how to translate between this new
format and the OpenFlow 1.0 fixed format. It seemed somewhat
inconsistent and backward to treat fields as exact-match in one
format and forbid matching them in the other, so instead the
treatment of inapplicable fields in the fixed-length format was
changed from exact match on 0 to wildcarding. (A better
classifier had by now eliminated software performance problems
with wildcards.)
</p>
<p>
The OpenFlow 1.0.1 errata (released only in 2012) added some
additional explanation [OpenFlow 1.0.1, section 3.4], but it did
not mandate specific behavior because of variation among
implementations.
</p>
<h3>OpenFlow 1.1</h3>
<p>
The OpenFlow 1.1 protocol match format was designed as a type/length/value
(TLV) format to allow for future flexibility. The specification
standardized only a single type <code>OFPMT_STANDARD</code> (0) with a
fixed-size payload, described here. The additional fields and bitwise
masks in OpenFlow 1.1 cause this match structure to be over twice as large
as in OpenFlow 1.0, 88 bytes versus 40.
</p>
<p>
OpenFlow 1.1 added support for the following fields:
</p>
<ul>
<li>SCTP source and destination port.</li>
<li>MPLS label and traffic control (TC) fields.</li>
<li>One 64-bit register (named ``metadata'').</li>
</ul>
<p>
OpenFlow 1.1 increased the width of the ingress port number field (and all
other port numbers in the protocol) from 16 bits to 32 bits.
</p>
<p>
OpenFlow 1.1 increased matching flexibility by introducing
arbitrary bitwise matching on Ethernet and IPv4 address fields and
on the new ``metadata'' register field. Switches were not
required to support all possible masks [OpenFlow 1.1, section
4.3].
</p>
<p>
By a strict reading of the specification, OpenFlow 1.1 removed
support for matching ICMPv4 type and code [OpenFlow 1.1, section
A.2.3], but this is likely an editing error because ICMP
matching is described elsewhere [OpenFlow 1.1, Table 3, Table 4,
Figure 4]. Open vSwitch does support ICMPv4 type and code
matching with OpenFlow 1.1.
</p>
<p>
OpenFlow 1.1 avoided the pitfalls of inapplicable fields that
OpenFlow 1.0 encountered, by requiring the switch to ignore the
specified field values [OpenFlow 1.1, section A.2.3]. It also
implied that the switch should ignore the bits that indicate
whether to match inapplicable fields.
</p>
<h4>Physical Ingress Port</h4>
<p>
OpenFlow 1.1 introduced a new pseudo-field, the physical ingress port. The
physical ingress port is only a pseudo-field because it cannot be used for
matching. It appears only one place in the protocol, in the ``packet-in''
message that passes a packet received at the switch to an OpenFlow
controller.
</p>
<p>
A packet's ingress port and physical ingress port are identical except for
packets processed by a switch feature such as bonding or tunneling that
makes a packet appear to arrive on a ``virtual'' port associated with the
bond or the tunnel. For such packets, the ingress port is the virtual port
and the physical ingress port is, naturally, the physical port. Open
vSwitch implements both bonding and tunneling, but its bonding
implementation does not use virtual ports and its tunnels are typically not
on the same OpenFlow switch as their physical ingress ports (which need not
be part of any switch), so the ingress port and physical ingress port are
always the same in Open vSwitch.
</p>
<h3>OpenFlow 1.2</h3>
<p>
OpenFlow 1.2 abandoned the fixed-length approach to matching. One reason
was size, since adding support for IPv6 address matching (now seen as
important), with bitwise masks, would have added 64 bytes to the match
length, increasing it from 88 bytes in OpenFlow 1.1 to over 150 bytes.
Extensibility had also become important as controller writers increasingly
wanted support for new fields without having to change messages throughout
the OpenFlow protocol. The challenges of carefully defining fixed-length
matches to avoid problems with inapplicable fields had also become clear
over time.
</p>
<p>
Therefore, OpenFlow 1.2 adopted a flow format using a flexible
type-length-value (TLV) representation, in which each TLV expresses a match
on one field. These TLVs were in turn encapsulated inside the outer TLV
wrapper introduced in OpenFlow 1.1 with the new identifier
<code>OFPMT_OXM</code> (1). (This wrapper fulfilled its intended purpose
of reducing the amount of churn in the protocol when changing match
formats; some messages that included matches remained unchanged from
OpenFlow 1.1 to 1.2 and later versions.)
</p>
<p>
OpenFlow 1.2 added support for the following fields:
</p>
<ul>
<li>ARP hardware addresses (SHA and THA).</li>
<li>IPv4 ECN.</li>
<li>IPv6 source and destination addresses, flow label, DSCP, ECN,
and protocol.</li>
<li>TCP, UDP, and SCTP port numbers when encapsulated inside IPv6.</li>
<li>ICMPv6 type and code.</li>
<li>ICMPv6 Neighbor Discovery target address and source and target
Ethernet addresses.</li>
</ul>
<!-- mention tun_id_from_cookie extension? -->
<p>
The OpenFlow 1.2 format, called <dfn>OXM</dfn> (<dfn>OpenFlow Extensible
Match</dfn>), was modeled closely on an extension to OpenFlow 1.0
introduced in Open vSwitch 1.1 called <dfn>NXM</dfn> (<dfn>Nicira Extended
Match</dfn>). Each OXM or NXM TLV has the following format:
</p>
<diagram>
<header name="type">
<bits name="vendor/class" above="16" width=".75"/>
<bits name="field" above="7" width=".4"/>
</header>
<nospace/>
<header name="">
<bits name="HM" above="1" width=".25"/>
<bits name="length" above="8" width=".4"/>
</header>
<header name="">
<bits name="body" above="length bytes" width="1.7"/>
</header>
</diagram>
<p>
The most significant 16 bits of the NXM or OXM header, called
<code>vendor</code> by NXM and <code>class</code> by OXM, identify
an organization permitted to allocate identifiers for fields. NXM
allocates only two vendors, 0x0000 for fields supported by
OpenFlow 1.0 and 0x0001 for fields implemented as an Open vSwitch
extension. OXM assigns classes as follows:
</p>
<dl>
<dt>0x0000 (<code>OFPXMC_NXM_0</code>).</dt>
<dt>0x0001 (<code>OFPXMC_NXM_1</code>).</dt>
<dd>Reserved for NXM compatibility.</dd>
<dt>0x0002 to 0x7fff</dt>
<dd>
Reserved for allocation to ONF members, but none yet assigned.
</dd>
<dt>0x8000 (<code>OFPXMC_OPENFLOW_BASIC</code>)</dt>
<dd>
Used for most standard OpenFlow fields.
</dd>
<dt>0x8001 (<code>OFPXMC_PACKET_REGS</code>)</dt>
<dd>
Used for packet register fields in OpenFlow 1.5 and later.
</dd>
<dt>0x8002 to 0xfffe</dt>
<dd>
Reserved for the OpenFlow specification.
</dd>
<dt>0xffff (<code>OFPXMC_EXPERIMENTER</code>)</dt>
<dd>Experimental use.</dd>
</dl>
<p>
When <code>class</code> is 0xffff, the OXM header is extended to 64 bits by
using the first 32 bits of the body as an <code>experimenter</code> field
whose most significant byte is zero and whose remaining bytes are an
Organizationally Unique Identifier (OUI) assigned by the IEEE [IEEE OUI],
as shown below. OpenFlow says that support for experimenter fields is
optional. Open vSwitch 2.4 and later does support them, primarily so that
it can support the <code>ONFOXM_ET_</code>* code points defined by official
Open Networking Foundation extensions to OpenFlow 1.3 in e.g. [TCP Flags
Match Field Extension].
</p>
<diagram>
<header name="type">
<bits name="class" above="16" below="0xffff" width=".75"/>
<bits name="field" above="7" width=".4"/>
</header>
<nospace/>
<header name="">
<bits name="HM" above="1" width=".25"/>
<bits name="length" above="8" width=".4"/>
</header>
<header name="experimenter">
<bits name="zero" above="8" below="0x00" width=".4"/>
<bits name="OUI" above="24" width="1"/>
</header>
<header name="">
<bits name="body" above="(length - 4) bytes" width="1.7"/>
</header>
</diagram>
<p>
Taken as a unit, <code>class</code> (or <code>vendor</code>),
<code>field</code>, and <code>experimenter</code> (when present) uniquely
identify a particular field.
</p>
<p>
When <code>hasmask</code> (abbreviated <code>HM</code> above) is 0, the OXM
is an exact match on an entire field. In this case, the body (excluding
the experimenter field, if present) is a single value to be matched.
</p>
<p>
When <code>hasmask</code> is 1, the OXM is a bitwise match. The body
(excluding the experimenter field) consists of a value to match, followed
by the bitwise mask to apply. A 1-bit in the mask indicates that the
corresponding bit in the value should be matched and a 0-bit that it should
be ignored. For example, for an IP address field, a value of 192.168.0.0
followed by a mask of 255.255.0.0 would match addresses in the
196.168.0.0/16 subnet.
</p>
<ul>
<li>
Some fields might not support masking at all, and some fields that do
support masking might restrict it to certain patterns. For example,
fields that have IP address values might be restricted to CIDR masks.
The descriptions of individual fields note these restrictions.
</li>
<li>
An OXM TLV with a mask that is all zeros is not useful (although it is
not forbidden), because it is has the same effect as omitting the TLV
entirely.
</li>
<li>
It is not meaningful to pair a 0-bit in an OXM mask with a 1-bit in its
value, and Open vSwitch rejects such an OXM with the error
<code>OFPBMC_BAD_WILDCARDS</code>, as required by OpenFlow 1.3 and later.
</li>
</ul>
<p>
The <code>length</code> identifies the number of bytes in the body,
including the 4-byte <code>experimenter</code> header, if it is present.
Each OXM TLV has a fixed length; that is, given <code>class</code>,
<code>field</code>, <code>experimenter</code> (if present), and
<code>hasmask</code>, <code>length</code> is a constant. The
<code>length</code> is included explicitly to allow software to minimally
parse OXM TLVs of unknown types.
</p>
<p>
OXM TLVs must be ordered so that a field's prerequisites are satisfied
before it is parsed. For example, an OXM TLV that matches on the IPv4
source address field is only allowed following an OXM TLV that matches on
the Ethertype for IPv4. Similarly, an OXM TLV that matches on the TCP
source port must follow a TLV that matches an Ethertype of IPv4 or IPv6 and
one that matches an IP protocol of TCP (in that order). The order of OXM
TLVs is not otherwise restricted; no canonical ordering is defined.
</p>
<p>
A given field may be matched only once in a series of OXM TLVs.
</p>
<!-- EXT-482? -->
<h3>OpenFlow 1.3</h3>
<p>
OpenFlow 1.3 showed OXM to be largely successful, by adding new fields
without making any changes to how flow matches otherwise worked. It added
OXMs for the following fields supported by Open vSwitch:
</p>
<ul>
<li>Tunnel ID for ports associated with e.g. VXLAN or keyed GRE.</li>
<li>MPLS ``bottom of stack'' (BOS) bit.</li>
</ul>
<p>
OpenFlow 1.3 also added OXMs for the following fields not documented here
and not yet implemented by Open vSwitch:
</p>
<ul>
<li>IPv6 extension header handling.</li>
<li>PBB I-SID.</li>
</ul>
<h3>OpenFlow 1.4</h3>
<p>
OpenFlow 1.4 added OXMs for the following fields not documented here and
not yet implemented by Open vSwitch:
</p>
<ul>
<li>PBB UCA.</li>
</ul>
<h3>OpenFlow 1.5</h3>
<p>
OpenFlow 1.5 added OXMs for the following fields supported by Open vSwitch:
</p>
<ul>
<li>TCP flags.</li>
<li>Packet registers.</li>
<li>The output port in the OpenFlow action set.</li>
</ul>
<p>
OpenFlow 1.5 also added OXMs for the following fields not documented here
and not yet implemented by Open vSwitch:
</p>
<ul>
<li>Packet type.</li>
</ul>
<h1>Fields Reference</h1>
<p>
The following sections document the fields that Open vSwitch supports.
Each section provides introductory material on a group of related fields,
followed by information on each individual field. In addition to
field-specific information, each field begins with a table with entries for
the following important properties:
</p>
<dl>
<dt>Name</dt>
<dd>
The field's name, used for parsing and formatting the field, e.g. in
<code>ovs-ofctl</code> commands. For historical reasons, some fields
have an additional name that is accepted as an alternative in parsing.
This name, when there is one, is listed as well, e.g. ``<code>tun</code>
(aka <code>tunnel_id</code>).''
</dd>
<dt>Width</dt>
<dd>
The field's width, always a multiple of 8 bits. Some fields don't use
all of the bits, so this may be accompanied by an explanation. For
example, OpenFlow embeds the 2-bit IP ECN field as as the low bits in an
8-bit byte, and so its width is expressed as ``8 bits (only the
least-significant 2 bits may be nonzero).''
</dd>
<dt>Format</dt>
<dd>
<p>
How a value for the field is formatted or parsed by, e.g.,
<code>ovs-ofctl</code>. Some possibilities are generic:
</p>
<dl>
<dt>decimal</dt>
<dd>
Formats as a decimal number. On input, accepts decimal numbers or
hexadecimal numbers prefixed by <code>0x</code>.
</dd>
<dt>hexadecimal</dt>
<dd>
Formats as a hexadecimal number prefixed by <code>0x</code>. On
input, accepts decimal numbers or hexadecimal numbers prefixed by
<code>0x</code>. (The default for parsing is <em>not</em>
hexadecimal: only a <code>0x</code> prefix causes input to be treated
as hexadecimal.)
</dd>
<dt>Ethernet</dt>
<dd>
Formats and accepts the common Ethernet address format
<code><var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var></code>.
</dd>
<dt>IPv4</dt>
<dd>
Formats and accepts the dotted-quad format
<code><var>a</var>.<var>b</var>.<var>c</var>.<var>d</var></code>.
For bitwise matches, formats and accepts
<code><var>address</var>/<var>length</var></code> CIDR notation in
addition to <code><var>address</var>/<var>mask</var></code>.
</dd>
<dt>IPv6</dt>
<dd>
Formats and accepts the common IPv6 address formats, plus CIDR
notation for bitwise matches.
</dd>
<dt>OpenFlow 1.0 port</dt>
<dd>
Accepts 16-bit port numbers in decimal, plus OpenFlow well-known port
names (e.g. <code>IN_PORT</code>) in uppercase or lowercase.
</dd>
<dt>OpenFlow 1.1+ port</dt>
<dd>
Same syntax as OpenFlow 1.0 ports but for 32-bit OpenFlow 1.1+ port
number fields.
</dd>
</dl>
<p>
Other, field-specific formats are explained along with their fields.
</p>
</dd>
<dt>Masking</dt>
<dd>
For most fields, this says ``arbitrary bitwise masks,'' meaning that a
flow may match any combination of bits in the field. Some fields
instead say ``exact match only,'' which means that a flow that matches
on this field must match on the whole field instead of just certain
bits. Either way, this reports masking support for the latest version
of Open vSwitch using OXM or NXM (that is, either OpenFlow 1.2+ or
OpenFlow 1.0 plus Open vSwitch NXM extensions). In particular,
OpenFlow 1.0 (without NXM) and 1.1 don't always support masking even if
Open vSwitch itself does; refer to the <em>OpenFlow 1.0</em> and
<em>OpenFlow 1.1</em> rows to learn about masking with these protocol
versions.
</dd>
<dt>Prerequisites</dt>
<dd>
<p>
Requirements that must be met to match on this field. For example,
<ref field="ip_src"/> has IPv4 as a prerequisite, meaning that a match
must include <code>eth_type=0x0800</code> to match on the IPv4 source
address. The following prerequisites, with their requirements, are
currently in use:
</p>
<dl>
<dt>none</dt>
<dd>(no requirements)</dd>
<dt>VLAN VID</dt>
<dd><code>vlan_tci=0x1000/0x1000</code> (i.e. a VLAN header is
present)</dd>
<dt>ARP</dt>
<dd><code>eth_type=0x0806</code> (ARP) or <code>eth_type=0x8035</code> (RARP)</dd>
<dt>IPv4</dt>
<dd><code>eth_type=0x0800</code></dd>
<dt>IPv6</dt>
<dd><code>eth_type=0x86dd</code></dd>
<dt>IPv4/IPv6</dt>
<dd>IPv4 or IPv6</dd>
<dt>MPLS</dt>
<dd><code>eth_type=0x8847</code> or <code>eth_type=0x8848</code></dd>
<dt>TCP</dt>
<dd>IPv4/IPv6 and <code>ip_proto=6</code></dd>
<dt>UDP</dt>
<dd>IPv4/IPv6 and <code>ip_proto=17</code></dd>
<dt>SCTP</dt>
<dd>IPv4/IPv6 and <code>ip_proto=132</code></dd>
<dt>ICMPv4</dt>
<dd>IPv4 and <code>ip_proto=1</code></dd>
<dt>ICMPv6</dt>
<dd>IPv6 and <code>ip_proto=58</code></dd>
<dt>ND solicit</dt>
<dd>ICMPv6 and <code>icmp_type=135</code> and <code>icmp_code=0</code></dd>
<dt>ND advert</dt>
<dd>ICMPv6 and <code>icmp_type=136</code> and <code>icmp_code=0</code></dd>
<dt>ND</dt>
<dd>ND solicit or ND advert</dd>
</dl>
<p>
The TCP, UDP, and SCTP prerequisites also have the special requirement
that <code>nw_frag</code> is not being used to select ``later
fragments.'' This is because only the first fragment of a fragmented
IPv4 or IPv6 datagram contains the TCP or UDP header.
</p>
</dd>
<dt>Access</dt>
<dd>
Most fields are ``read/write,'' which means that common OpenFlow actions
like <code>set_field</code> can modify them. Fields that are
``read-only'' cannot be modified in these general-purpose ways, although
there may be other ways that actions can modify them.
</dd>
<dt>OpenFlow 1.0</dt>
<dt>OpenFlow 1.1</dt>
<dd>
These rows report the level of support that OpenFlow 1.0 or OpenFlow 1.1,
respectively, has for a field. For OpenFlow 1.0, supported fields are
reported as either ``yes (exact match only)'' for fields that do not
support any bitwise masking or ``yes (CIDR match only)'' for fields that
support CIDR masking. OpenFlow 1.1 supported fields report either ``yes
(exact match only)'' or simply ``yes'' for fields that do support
arbitrary masks. These OpenFlow versions supported a fixed collection of
fields that cannot be extended, so many more fields are reported as ``not
supported.''
</dd>
<dt>OXM</dt>
<dt>NXM</dt>
<dd>
<p>
These rows report the OXM and NXM code points that correspond to a
given field. Either or both may be ``none.''
</p>
<p>
A field that has only an OXM code point is usually one that was
standardized before it was added to Open vSwitch. A field that has
only an NXM code point is usually one that is not yet standardized.
When a field has both OXM and NXM code points, it usually indicates
that it was introduced as an Open vSwitch extension under the NXM code
point, then later standardized under the OXM code point. A field can
have more than one OXM code point if it was standardized in OpenFlow
1.4 or later and additionally introduced as an official ONF extension
for OpenFlow 1.3. (A field that has neither OXM nor NXM code point is
typically an obsolete field that is supported in some other form using
OXM or NXM.)
</p>
<p>
Each code point in these rows is described in the form
``<code>NAME</code> (<var>number</var>) since OpenFlow <var>spec</var>
and Open vSwitch <var>version</var>,''
e.g. ``<code>OXM_OF_ETH_TYPE</code> (5) since OpenFlow 1.2 and Open
vSwitch 1.7.'' First, <code>NAME</code>, which specifies a name for
the code point, starts with a prefix that designates a class and, in
some cases, a vendor, as listed in the following table:
</p>
<oxm_classes/>
<p>
For more information on OXM/NXM classes and vendors, refer back to
<em>OpenFlow 1.2</em> under <em>Evolution of OpenFlow Fields</em>. The
<var>number</var> is the field number within the class and vendor. The
OpenFlow <var>spec</var> is the version of OpenFlow that standardized
the code point. It is omitted for NXM code points because they are
nonstandard. The <var>version</var> is the version of Open vSwitch
that first supported the code point.
</p>
</dd>
</dl>
<group title="Conjunctive Match">
<p>
An individual OpenFlow flow can match only a single value for each field.
However, situations often arise where one wants to match one of a set of
values within a field or fields. For matching a single field against a
set, it is straightforward and efficient to add multiple flows to the
flow table, one for each value in the set. For example, one might use
the following flows to send packets with IP source address <var>a</var>,
<var>b</var>, <var>c</var>, or <var>d</var> to the OpenFlow controller:
</p>
<pre>
ip,ip_src=<var>a</var> actions=controller
ip,ip_src=<var>b</var> actions=controller
ip,ip_src=<var>c</var> actions=controller
ip,ip_src=<var>d</var> actions=controller
</pre>
<p>
Similarly, these flows send packets with IP destination address
<var>e</var>, <var>f</var>, <var>g</var>, or <var>h</var> to the OpenFlow
controller:
</p>
<pre>
ip,ip_dst=<var>e</var> actions=controller
ip,ip_dst=<var>f</var> actions=controller
ip,ip_dst=<var>g</var> actions=controller
ip,ip_dst=<var>h</var> actions=controller
</pre>
<p>
Installing all of the above flows in a single flow table yields a
disjunctive effect: a packet is sent to the controller if
<code>ip_src</code> ∈ {<var>a</var>,<var>b</var>,<var>c</var>,<var>d</var>}
or <code>ip_dst</code> ∈
{<var>e</var>,<var>f</var>,<var>g</var>,<var>h</var>} (or both).
(Pedantically, if both of the above sets of flows are present in the flow
table, they should have different priorities, because OpenFlow says that
the results are undefined when two flows with same priority can both match
a single packet.)
</p>
<p>
Suppose, on the other hand, one wishes to match conjunctively, that is, to
send a packet to the controller only if both <code>ip_src</code> ∈
{<var>a</var>,<var>b</var>,<var>c</var>,<var>d</var>} and
<code>ip_dst</code> ∈
{<var>e</var>,<var>f</var>,<var>g</var>,<var>h</var>}. This requires 4 × 4
= 16 flows, one for each possible pairing of <code>ip_src</code> and
<code>ip_dst</code>. That is acceptable for our small example, but it does
not gracefully extend to larger sets or greater numbers of dimensions.
</p>
<p>
The <code>conjunction</code> action is a solution for conjunctive matches
that is built into Open vSwitch. A <code>conjunction</code> action ties groups of
individual OpenFlow flows into higher-level ``conjunctive flows''. Each
group corresponds to one dimension, and each flow within the group matches
one possible value for the dimension. A packet that matches one flow from
each group matches the conjunctive flow.
</p>
<p>
To implement a conjunctive flow with <code>conjunction</code>, assign the
conjunctive flow a 32-bit <var>id</var>, which must be unique within an
OpenFlow table. Assign each of the <var>n</var> ≥ 2 dimensions a unique
number from 1 to <var>n</var>; the ordering is unimportant. Add one flow
to the OpenFlow flow table for each possible value of each dimension with
<code>conjunction(<var>id</var>, <var>k</var>/<var>n</var>)</code> as the
flow's actions, where <var>k</var> is the number assigned to the flow's
dimension. Together, these flows specify the conjunctive flow's match
condition. When the conjunctive match condition is met, Open vSwitch looks
up one more flow that specifies the conjunctive flow's actions and receives
its statistics. This flow is found by setting <code>conj_id</code> to the
specified <var>id</var> and then again searching the flow table.
</p>
<p>
The following flows provide an example. Whenever the IP source is one of
the values in the flows that match on the IP source (dimension 1 of 2),
<em>and</em> the IP destination is one of the values in the flows that
match on IP destination (dimension 2 of 2), Open vSwitch searches for a
flow that matches <code>conj_id</code> against the conjunction ID (1234),
finding the first flow listed below.
</p>
<pre>
conj_id=1234 actions=controller
ip,ip_src=10.0.0.1 actions=conjunction(1234, 1/2)
ip,ip_src=10.0.0.4 actions=conjunction(1234, 1/2)
ip,ip_src=10.0.0.6 actions=conjunction(1234, 1/2)
ip,ip_src=10.0.0.7 actions=conjunction(1234, 1/2)
ip,ip_dst=10.0.0.2 actions=conjunction(1234, 2/2)
ip,ip_dst=10.0.0.5 actions=conjunction(1234, 2/2)
ip,ip_dst=10.0.0.7 actions=conjunction(1234, 2/2)
ip,ip_dst=10.0.0.8 actions=conjunction(1234, 2/2)
</pre>
<p>
Many subtleties exist:
</p>
<ul>
<li>
In the example above, every flow in a single dimension has the same form,
that is, dimension 1 matches on <code>ip_src</code> and dimension 2 on
<code>ip_dst</code>, but this is not a requirement. Different flows
within a dimension may match on different bits within a field (e.g. IP
network prefixes of different lengths, or TCP/UDP port ranges as bitwise
matches), or even on entirely different fields (e.g. to match packets for
TCP source port 80 or TCP destination port 80).
</li>
<li>
The flows within a dimension can vary their matches across more than
one field, e.g. to match only specific pairs of IP source and
destination addresses or L4 port numbers.
</li>
<li>
A flow may have multiple <code>conjunction</code> actions, with different
<code>id</code> values. This is useful for multiple conjunctive flows with
overlapping sets. If one conjunctive flow matches packets with both
<code>ip_src</code> ∈ {<var>a</var>,<var>b</var>} and <code>ip_dst</code> ∈
{<var>d</var>,<var>e</var>} and a second conjunctive flow matches <code>ip_src</code>
∈ {<var>b</var>,<var>c</var>} and <code>ip_dst</code> ∈ {<var>f</var>,<var>g</var>}, for
example, then the flow that matches <code>ip_src=</code><var>b</var> would have two
<code>conjunction</code> actions, one for each conjunctive flow. The order
of <code>conjunction</code> actions within a list of actions is not
significant.
</li>
<li>
A flow with <code>conjunction</code> actions may also include <code>note</code>
actions for annotations, but not any other kind of actions. (They
would not be useful because they would never be executed.)
</li>
<li>
All of the flows that constitute a conjunctive flow with a given
<var>id</var> must have the same priority. (Flows with the same <var>id</var>
but different priorities are currently treated as different
conjunctive flows, that is, currently <var>id</var> values need only be
unique within an OpenFlow table at a given priority. This behavior
isn't guaranteed to stay the same in later releases, so please use
<var>id</var> values unique within an OpenFlow table.)
</li>
<li>
Conjunctive flows must not overlap with each other, at a given
priority, that is, any given packet must be able to match at most one
conjunctive flow at a given priority. Overlapping conjunctive flows
yield unpredictable results.
</li>
<li>
Following a conjunctive flow match, the search for the flow with
<code>conj_id=</code><var>id</var> is done in the same general-purpose way as
other flow table searches, so one can use flows with
<code>conj_id=</code><var>id</var> to act differently depending on
circumstances. (One exception is that the search for the
<code>conj_id=</code><var>id</var> flow itself ignores conjunctive flows, to
avoid recursion.) If the search with <code>conj_id=</code><var>id</var> fails,
Open vSwitch acts as if the conjunctive flow had not matched at all, and
continues searching the flow table for other matching flows.
</li>
<li>
<p>
OpenFlow prerequisite checking occurs for the flow with
<code>conj_id=</code><var>id</var> in the same way as any other flow, e.g. in
an OpenFlow 1.1+ context, putting a <code>mod_nw_src</code> action into the example
above would require adding an <code>ip</code> match, like this:
</p>
<pre>
conj_id=1234,ip actions=mod_nw_src:1.2.3.4,controller
</pre>
</li>
<li>
OpenFlow prerequisite checking also occurs for the individual flows
that comprise a conjunctive match in the same way as any other flow.
</li>
<li>
The flows that constitute a conjunctive flow do not have useful
statistics. They are never updated with byte or packet counts, and so
on. (For such a flow, therefore, the idle and hard timeouts work much
the same way.)
</li>
<li>
<p>
Sometimes there is a choice of which flows include a particular match.
For example, suppose that we added an extra constraint to our example,
to match on <code>ip_src</code> ∈
{<var>a</var>,<var>b</var>,<var>c</var>,<var>d</var>} and
<code>ip_dst</code> ∈
{<var>e</var>,<var>f</var>,<var>g</var>,<var>h</var>} and
<code>tcp_dst</code> = <var>i</var>. One way to implement this is to
add the new constraint to the <code>conj_id</code> flow, like this:
</p>
<pre>
conj_id=1234,tcp,tcp_dst=<var>i</var> actions=mod_nw_src:1.2.3.4,controller
</pre>
<p>
but <em>this is not recommended</em> because of the cost of the extra
flow table lookup. Instead, add the constraint to the individual
flows, either in one of the dimensions or (slightly better) all of
them.
</p>
</li>
<li>
A conjunctive match must have <var>n</var> ≥ 2 dimensions (otherwise a
conjunctive match is not necessary). Open vSwitch enforces this.
</li>
<li>
Each dimension within a conjunctive match should ordinarily have more
than one flow. Open vSwitch does not enforce this.
</li>
</ul>
<field id="MFF_CONJ_ID" title="Conjunction ID">
Used for conjunctive matching. See above for more information.
</field>
</group>
<group title="Tunnel">
<p>
The fields in this group relate to tunnels, which Open vSwitch
supports in several forms (GRE, VXLAN, and so on). Most of
these fields do appear in the wire format of a packet, so they
are data fields from that point of view, but they are metadata
from an OpenFlow flow table point of view because they do not
appear in packets that are forwarded to the controller or to
ordinary (non-tunnel) output ports.
</p>
<p>
Open vSwitch supports a spectrum of usage models for mapping
tunnels to OpenFlow ports:
</p>
<dl>
<dt>``Port-based'' tunnels</dt>
<dd>
<p>
In this model, an OpenFlow port represents one tunnel: it matches a
particular type of tunnel traffic between two IP endpoints, with a
particular tunnel key (if keys are in use). In this situation, <ref
field="in_port"/> suffices to distinguish one tunnel from another, so
the tunnel header fields have little importance for OpenFlow
processing. (They are still populated and may be used if it is
convenient.) The tunnel header fields play no role in sending
packets out such an OpenFlow port, either, because the OpenFlow port
itself fully specifies the tunnel headers.
</p>
<p>
The following Open vSwitch commands create a bridge
<code>br-int</code>, add port <code>tap0</code> to the bridge as
OpenFlow port 1, establish a port-based GRE tunnel between the local
host and remote IP 192.168.1.1 using GRE key 5001 as OpenFlow port 2,
and arranges to forward all traffic from <code>tap0</code> to the
tunnel and vice versa:
</p>
<pre>
ovs-vsctl add-br br-int
ovs-vsctl add-port br-int tap0 -- set interface tap0 ofport_request=1
ovs-vsctl add-port br-int gre0 --
set interface gre0 ofport_request=2 type=gre \
options:remote_ip=192.168.1.1 options:key=5001
ovs-ofctl add-flow br-int in_port=1,actions=2
ovs-ofctl add-flow br-int in_port=2,actions=1
</pre>
</dd>
<dt>``Flow-based'' tunnels</dt>
<dd>
<p>
In this model, one OpenFlow port represents all possible tunnels of a
given type with an endpoint on the current host, for example, all GRE
tunnels. In this situation, <ref field="in_port"/> only indicates
that traffic was received on the particular kind of tunnel. This is
where the tunnel header fields are most important: they allow the
OpenFlow tables to discriminate among tunnels based on their IP
endpoints or keys. Tunnel header fields also determine the IP
endpoints and keys of packets sent out such a tunnel port.
</p>
<p>
The following Open vSwitch commands create a bridge
<code>br-int</code>, add port <code>tap0</code> to the
bridge as OpenFlow port 1, establish a flow-based GRE tunnel
port 3, and arranges to forward all traffic from
<code>tap0</code> to remote IP 192.168.1.1 over a GRE tunnel
with key 5001 and vice versa:
</p>
<pre>
ovs-vsctl add-br br-int
ovs-vsctl add-port br-int tap0 -- set interface tap0 ofport_request=1
ovs-vsctl add-port br-int allgre --
set interface gre0 ofport_request=3 type=gre \
options:remote_ip=flow options:key=flow
ovs-ofctl add-flow br-int \
'in_port=1 actions=set_tunnel:5001,set_field:192.168.1.1->tun_dst,3'
ovs-ofctl add-flow br-int 'in_port=3,tun_src=192.168.1.1,tun_id=5001 actions=1'
</pre>
</dd>
<dt>Mixed models.</dt>
<dd>
<p>
One may define both flow-based and port-based tunnels at the
same time. For example, it is valid and possibly useful to
create and configure both <code>gre0</code> and
<code>allgre</code> tunnel ports described above.
</p>
<p>
Traffic is attributed on ingress to the most specific
matching tunnel. For example, <code>gre0</code> is more
specific than <code>allgre</code>. Therefore, if both
exist, then <code>gre0</code> will be the ingress port for any
GRE traffic received from 192.168.1.1 with key 5001.
</p>
<p>
On egress, traffic may be directed to any appropriate tunnel
port. If both <code>gre0</code> and <code>allgre</code> are
configured as already described, then the actions
<code>2</code> and
<code>set_tunnel:5001,set_field:192.168.1.1->tun_dst,3</code>
send the same tunnel traffic.
</p>
</dd>
<dt>Intermediate models.</dt>
<dd>
Ports may be configured as partially flow-based. For example,
one may define an OpenFlow port that represents tunnels
between a pair of endpoints but leaves the flow table to
discriminate on the flow key.
</dd>
</dl>
<p>
<code>ovs-vswitchd.conf.db</code>(5) describes all the details of tunnel
configuration.
</p>
<p>
These fields do not have any prerequisites, which means that a
flow may match on any or all of them, in any combination.
</p>
<p>
These fields are zeros for packets that did not arrive on a tunnel.
</p>
<field id="MFF_TUN_ID" title="Tunnel ID">
<p>
Many kinds of tunnels support a tunnel ID:
</p>
<ul>
<li>
VXLAN and Geneve have a 24-bit virtual network identifier (VNI).
</li>
<li>LISP has a 24-bit instance ID.</li>
<li>GRE has an optional 32-bit key.</li>
<li>STT has a 64-bit key.</li>
</ul>
<p>
When a packet is received from a tunnel, this field holds the
tunnel ID in its least significant bits, zero-extended to fit.
This field is zero if the tunnel does not support an ID, or if
no ID is in use for a tunnel type that has an optional ID, or
if an ID of zero received, or if the packet was not received
over a tunnel.
</p>
<p>
When a packet is output to a tunnel port, the tunnel
configuration determines whether the tunnel ID is taken from
this field or bound to a fixed value. See the earlier
description of ``port-based'' and ``flow-based'' tunnels for
more information.
</p>
<p>
The following diagram shows the origin of this field in a
typical keyed GRE tunnel:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" below="47" width="0.4"/>
<bits name="src" above="32" width="0.4"/>
<bits name="dst" above="32" width="0.4"/>
</header>
<header name="GRE">
<bits name="..." above="16" width="0.4"/>
<bits name="type" above="16" below="0x6558" width="0.4"/>
<bits name="key" above="32" width=".4" fill="yes"/>
</header>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" width="0.4"/>
</header>
<dots/>
</diagram>
</field>
<field id="MFF_TUN_SRC" title="Tunnel IPv4 Source">
<p>
When a packet is received from a tunnel, this field is the
source address in the outer IP header of the tunneled packet.
This field is zero if the packet was not received over a
tunnel.
</p>
<p>
When a packet is output to a flow-based tunnel port, this
field influences the IPv4 source address used to send the
packet. If it is zero, then the kernel chooses an appropriate
IP address based using the routing table.
</p>
<p>
The following diagram shows the origin of this field in a
typical keyed GRE tunnel:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" below="47" width="0.4"/>
<bits name="src" above="32" width="0.4" fill="yes"/>
<bits name="dst" above="32" width="0.4"/>
</header>
<header name="GRE">
<bits name="..." above="16" width="0.4"/>
<bits name="type" above="16" below="0x6558" width="0.4"/>
<bits name="key" above="32" width=".4"/>
</header>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" width="0.4"/>
</header>
<dots/>
</diagram>
</field>
<field id="MFF_TUN_DST" title="Tunnel IPv4 Destination">
<p>
When a packet is received from a tunnel, this field is the
destination address in the outer IP header of the tunneled
packet. This field is zero if the packet was not received
over a tunnel.
</p>
<p>
When a packet is output to a flow-based tunnel port, this
field specifies the destination to which the tunnel packet is
sent.
</p>
<p>
The following diagram shows the origin of this field in a
typical keyed GRE tunnel:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" below="47" width="0.4"/>
<bits name="src" above="32" width="0.4"/>
<bits name="dst" above="32" width="0.4" fill="yes"/>
</header>
<header name="GRE">
<bits name="..." above="16" width="0.4"/>
<bits name="type" above="16" below="0x6558" width="0.4"/>
<bits name="key" above="32" width=".4"/>
</header>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" width="0.4"/>
</header>
<dots/>
</diagram>
</field>
<field id="MFF_TUN_IPV6_SRC" title="Tunnel IPv6 Source">
Similar to <ref field="tun_src"/>, but for tunnels over IPv6.
</field>
<field id="MFF_TUN_IPV6_DST" title="Tunnel IPv6 Destination">
Similar to <ref field="tun_dst"/>, but for tunnels over IPv6.
</field>
<h2>VXLAN Group-Based Policy Fields</h2>
<p>
The VXLAN header is defined as follows [RFC 7348], where the
<code>I</code> bit must be set to 1, unlabeled bits or those labeled
<code>reserved</code> must be set to 0, and Open vSwitch makes the VNI
available via <ref field="tun_id"/>:
</p>
<diagram>
<header name="VXLAN flags">
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="I" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
</header>
<nospace/>
<header>
<bits name="reserved" above="24" width="1.2"/>
<bits name="VNI" above="24" width="1.2"/>
<bits name="reserved" above="8" width=".5"/>
</header>
</diagram>
<p>
VXLAN Group-Based Policy [VXLAN Group Policy Option] adds new
interpretations to existing bits in the VXLAN header, reinterpreting it
as follows, with changes highlighted:
</p>
<diagram>
<header name="GBP flags">
<bits name="" above="1" width="0.15"/>
<bits name="D" above="1" width="0.15" fill="yes"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="A" above="1" width="0.15" fill="yes"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
</header>
<nospace/>
<header>
<bits name="group policy ID" above="24" width="1.2" fill="yes"/>
<bits name="VNI" above="24" width="1.2"/>
<bits name="reserved" above="8" width=".5"/>
</header>
</diagram>
<p>
Open vSwitch makes GBP fields and flags available through the following
fields. Only packets that arrive over a VXLAN tunnel with the GBP
extension enabled have these fields set. In other packets they are zero
on receive and ignored on transmit.
</p>
<field id="MFF_TUN_GBP_ID" title="VXLAN Group-Based Policy ID">
<p>
For a packet tunneled over VXLAN with the Group-Based Policy (GBP)
extension, this field represents the GBP policy ID, as shown above.
</p>
</field>
<field id="MFF_TUN_GBP_FLAGS" title="VXLAN Group-Based Policy Flags">
<p>
For a packet tunneled over VXLAN with the Group-Based Policy (GBP)
extension, this field represents the GBP policy flags, as shown above.
</p>
<p>
The field has the format shown below:
</p>
<diagram>
<header name="GBP Flags">
<bits name="" above="1" width="0.15"/>
<bits name="D" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="A" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
<bits name="" above="1" width="0.15"/>
</header>
</diagram>
<p>
Unlabeled bits are reserved and must be transmitted as 0. The VXLAN
GBP draft defines the other bits' meanings as:
</p>
<dl>
<dt><code>D</code> (Don't Learn)</dt>
<dd>
When set, this bit indicates that the egress tunnel endpoint must not
learn the source address of the encapsulated frame.
</dd>
<dt><code>A</code> (Applied)</dt>
<dd>
When set, indicates that the group policy has already been applied to
this packet. Devices must not apply policies when the A bit is set.
</dd>
</dl>
</field>
<h2>Geneve Fields</h2>
<p>
These fields provide access to additional features in the Geneve
tunneling protocol [Geneve]. Their names are somewhat generic in the
hope that the same fields could be reused for other protocols in the
future; for example, the NSH protocol [NSH] supports TLV options whose
form is identical to that for Geneve options.
</p>
<field id="MFF_TUN_METADATA0" title="Generic Tunnel Option 0">
<p>
The above information specifically covers generic tunnel option 0, but
Open vSwitch supports 64 options, numbered 0 through 63, whose
NXM field numbers are 40 through 103.
</p>
<p>
These fields provide OpenFlow access to the generic type-length-value
options defined by the Geneve tunneling protocol or other protocols
with options in the same TLV format as Geneve options. Each of these
options has the following wire format:
</p>
<diagram>
<header name="header">
<bits name="class" above="16" width="0.6"/>
<bits name="type" above="8" width="0.5"/>
<bits name="res" above="3" below="0" width="0.25"/>
<bits name="length" above="5" width="0.4"/>
</header>
<nospace/>
<header name="body">
<bits name="value" above="4×(length - 1) bytes" width="1.7"/>
</header>
</diagram>
<p>
Taken together, the <code>class</code> and <code>type</code> in the
option format mean that there are about 16 million distinct kinds of
TLV options, too many to give individual OXM code points. Thus, Open
vSwitch requires the user to define the TLV options of interest, by
binding up to 64 TLV options to generic tunnel option NXM code points.
Each option may have up to 124 bytes in its body, the maximum allowed
by the TLV format, but bound options may total at most 252 bytes of
body.
</p>
<p>
Open vSwitch extensions to the OpenFlow protocol bind TLV options to
NXM code points. The <code>ovs-ofctl</code>(8) program offers one way
to use these extensions, e.g. to configure a mapping from a TLV option
with <code>class</code> <code>0xffff</code>, <code>type</code>
<code>0</code>, and a body length of 4 bytes:
</p>
<pre>
ovs-ofctl add-tlv-map br0 "{class=0xffff,type=0,len=4}->tun_metadata0"
</pre>
<p>
Once a TLV option is properly bound, it can be accessed and modified
like any other field, e.g. to send packets that have value 1234 for the
option described above to the controller:
</p>
<pre>
ovs-ofctl add-flow br0 tun_metadata0=1234,actions=controller
</pre>
<p>
An option not received or not bound is matched as all zeros.
</p>
</field>
<!--- XXX need a way to define a range of OXMs -->
<field id="MFF_TUN_METADATA1" title="Generic Tunnel Option 1" hidden="yes"/>
<field id="MFF_TUN_METADATA2" title="Generic Tunnel Option 2" hidden="yes"/>
<field id="MFF_TUN_METADATA3" title="Generic Tunnel Option 3" hidden="yes"/>
<field id="MFF_TUN_METADATA4" title="Generic Tunnel Option 4" hidden="yes"/>
<field id="MFF_TUN_METADATA5" title="Generic Tunnel Option 5" hidden="yes"/>
<field id="MFF_TUN_METADATA6" title="Generic Tunnel Option 6" hidden="yes"/>
<field id="MFF_TUN_METADATA7" title="Generic Tunnel Option 7" hidden="yes"/>
<field id="MFF_TUN_METADATA8" title="Generic Tunnel Option 8" hidden="yes"/>
<field id="MFF_TUN_METADATA9" title="Generic Tunnel Option 9" hidden="yes"/>
<field id="MFF_TUN_METADATA10" title="Generic Tunnel Option 10" hidden="yes"/>
<field id="MFF_TUN_METADATA11" title="Generic Tunnel Option 11" hidden="yes"/>
<field id="MFF_TUN_METADATA12" title="Generic Tunnel Option 12" hidden="yes"/>
<field id="MFF_TUN_METADATA13" title="Generic Tunnel Option 13" hidden="yes"/>
<field id="MFF_TUN_METADATA14" title="Generic Tunnel Option 14" hidden="yes"/>
<field id="MFF_TUN_METADATA15" title="Generic Tunnel Option 15" hidden="yes"/>
<field id="MFF_TUN_METADATA16" title="Generic Tunnel Option 16" hidden="yes"/>
<field id="MFF_TUN_METADATA17" title="Generic Tunnel Option 17" hidden="yes"/>
<field id="MFF_TUN_METADATA18" title="Generic Tunnel Option 18" hidden="yes"/>
<field id="MFF_TUN_METADATA19" title="Generic Tunnel Option 19" hidden="yes"/>
<field id="MFF_TUN_METADATA20" title="Generic Tunnel Option 20" hidden="yes"/>
<field id="MFF_TUN_METADATA21" title="Generic Tunnel Option 21" hidden="yes"/>
<field id="MFF_TUN_METADATA22" title="Generic Tunnel Option 22" hidden="yes"/>
<field id="MFF_TUN_METADATA23" title="Generic Tunnel Option 23" hidden="yes"/>
<field id="MFF_TUN_METADATA24" title="Generic Tunnel Option 24" hidden="yes"/>
<field id="MFF_TUN_METADATA25" title="Generic Tunnel Option 25" hidden="yes"/>
<field id="MFF_TUN_METADATA26" title="Generic Tunnel Option 26" hidden="yes"/>
<field id="MFF_TUN_METADATA27" title="Generic Tunnel Option 27" hidden="yes"/>
<field id="MFF_TUN_METADATA28" title="Generic Tunnel Option 28" hidden="yes"/>
<field id="MFF_TUN_METADATA29" title="Generic Tunnel Option 29" hidden="yes"/>
<field id="MFF_TUN_METADATA30" title="Generic Tunnel Option 30" hidden="yes"/>
<field id="MFF_TUN_METADATA31" title="Generic Tunnel Option 31" hidden="yes"/>
<field id="MFF_TUN_METADATA32" title="Generic Tunnel Option 32" hidden="yes"/>
<field id="MFF_TUN_METADATA33" title="Generic Tunnel Option 33" hidden="yes"/>
<field id="MFF_TUN_METADATA34" title="Generic Tunnel Option 34" hidden="yes"/>
<field id="MFF_TUN_METADATA35" title="Generic Tunnel Option 35" hidden="yes"/>
<field id="MFF_TUN_METADATA36" title="Generic Tunnel Option 36" hidden="yes"/>
<field id="MFF_TUN_METADATA37" title="Generic Tunnel Option 37" hidden="yes"/>
<field id="MFF_TUN_METADATA38" title="Generic Tunnel Option 38" hidden="yes"/>
<field id="MFF_TUN_METADATA39" title="Generic Tunnel Option 39" hidden="yes"/>
<field id="MFF_TUN_METADATA40" title="Generic Tunnel Option 40" hidden="yes"/>
<field id="MFF_TUN_METADATA41" title="Generic Tunnel Option 41" hidden="yes"/>
<field id="MFF_TUN_METADATA42" title="Generic Tunnel Option 42" hidden="yes"/>
<field id="MFF_TUN_METADATA43" title="Generic Tunnel Option 43" hidden="yes"/>
<field id="MFF_TUN_METADATA44" title="Generic Tunnel Option 44" hidden="yes"/>
<field id="MFF_TUN_METADATA45" title="Generic Tunnel Option 45" hidden="yes"/>
<field id="MFF_TUN_METADATA46" title="Generic Tunnel Option 46" hidden="yes"/>
<field id="MFF_TUN_METADATA47" title="Generic Tunnel Option 47" hidden="yes"/>
<field id="MFF_TUN_METADATA48" title="Generic Tunnel Option 48" hidden="yes"/>
<field id="MFF_TUN_METADATA49" title="Generic Tunnel Option 49" hidden="yes"/>
<field id="MFF_TUN_METADATA50" title="Generic Tunnel Option 50" hidden="yes"/>
<field id="MFF_TUN_METADATA51" title="Generic Tunnel Option 51" hidden="yes"/>
<field id="MFF_TUN_METADATA52" title="Generic Tunnel Option 52" hidden="yes"/>
<field id="MFF_TUN_METADATA53" title="Generic Tunnel Option 53" hidden="yes"/>
<field id="MFF_TUN_METADATA54" title="Generic Tunnel Option 54" hidden="yes"/>
<field id="MFF_TUN_METADATA55" title="Generic Tunnel Option 55" hidden="yes"/>
<field id="MFF_TUN_METADATA56" title="Generic Tunnel Option 56" hidden="yes"/>
<field id="MFF_TUN_METADATA57" title="Generic Tunnel Option 57" hidden="yes"/>
<field id="MFF_TUN_METADATA58" title="Generic Tunnel Option 58" hidden="yes"/>
<field id="MFF_TUN_METADATA59" title="Generic Tunnel Option 59" hidden="yes"/>
<field id="MFF_TUN_METADATA60" title="Generic Tunnel Option 60" hidden="yes"/>
<field id="MFF_TUN_METADATA61" title="Generic Tunnel Option 61" hidden="yes"/>
<field id="MFF_TUN_METADATA62" title="Generic Tunnel Option 62" hidden="yes"/>
<field id="MFF_TUN_METADATA63" title="Generic Tunnel Option 63" hidden="yes"/>
<field id="MFF_TUN_FLAGS" title="Tunnel Flags">
<p>
Flags indicating various aspects of the tunnel encapsulation.
</p>
<p>
Matches on this field are most conveniently written in terms of
symbolic names (given in the diagram below), each preceded by either
<code>+</code> for a flag that must be set, or <code>-</code> for a
flag that must be unset, without any other delimiters between the
flags. Flags not mentioned are wildcarded. For example,
<code>tun_flags=+oam</code> matches only OAM packets. Matches can also
be written as <code><var>flags</var>/<var>mask</var></code>, where
<var>flags</var> and <var>mask</var> are 16-bit numbers in decimal or
in hexadecimal prefixed by <code>0x</code>.
</p>
<p>
Currently, only one flag is defined:
</p>
<dl>
<dt><code>oam</code></dt>
<dd>
The tunnel protocol indicated that this is an OAM (Operations and
Management) control packet.
</dd>
</dl>
<p>
The switch may reject matches against unknown flags.
</p>
<p>
Newer versions of Open vSwitch may introduce additional flags with new
meanings. It is therefore not recommended to use an exact match on
this field since the behavior of these new flags is unknown and should
be ignored.
</p>
<p>
For non-tunneled packets, the value is 0.
</p>
</field>
<!-- Open vSwitch uses the following fields internally, but it
does not expose them to the user via OpenFlow, so we do not
document them. -->
<field id="MFF_TUN_TTL" title="Tunnel IPv4 Time-to-Live" internal="yes"/>
<field id="MFF_TUN_TOS" title="Tunnel IPv4 Type of Service" internal="yes"/>
</group>
<group title="Metadata">
<p>
These fields relate to the origin or treatment of a packet, but
they are not extracted from the packet data itself.
</p>
<field id="MFF_IN_PORT" title="Ingress Port">
<p>
The OpenFlow port on which the packet being processed arrived.
This is a 16-bit field that holds an OpenFlow 1.0 port number.
For receiving a packet, the only values that appear in this
field are:
</p>
<dl>
<dt>1 through <code>0xfeff</code> (65,279), inclusive.</dt>
<dd>
Conventional OpenFlow port numbers.
</dd>
<dt><code>OFPP_LOCAL</code> (<code>0xfffe</code> or 65,534).</dt>
<dd>
<p>
The ``local'' port, which in Open vSwitch is always named
the same as the bridge itself. This represents a
connection between the switch and the local TCP/IP stack.
This port is where an IP address is most commonly
configured on an Open vSwitch switch.
</p>
<p>
OpenFlow does not require a switch to have a local port,
but all existing versions of Open vSwitch have always
included a local port. <b>Future Directions:</b> Future
versions of Open vSwitch might be able to optionally omit
the local port, if someone submits code to implement such
a feature.
</p>
</dd>
<dt><code>OFPP_NONE</code> (OpenFlow 1.0) or <code>OFPP_ANY</code> (OpenFlow 1.1+) (<code>0xffff</code> or 65,535).</dt>
<dt><code>OFPP_CONTROLLER</code> (<code>0xfffd</code> or 65,533).</dt>
<dd>
<p>
When a controller injects a packet into an OpenFlow switch
with a ``packet-out'' request, it can specify one of these
ingress ports to indicate that the packet was generated
internally rather than having been received on some port.
</p>
<p>
OpenFlow 1.0 specified <code>OFPP_NONE</code> for this
purpose. Despite that, some controllers used
<code>OFPP_CONTROLLER</code>, and some switches only
accepted <code>OFPP_CONTROLLER</code>, so OpenFlow 1.0.2
required support for both ports. OpenFlow 1.1 and later
were more clearly drafted to allow only
<code>OFPP_CONTROLLER</code>. For maximum compatibility,
Open vSwitch allows both ports with all OpenFlow versions.
</p>
</dd>
</dl>
<p>
Values not mentioned above will never appear when receiving a
packet, including the following notable values:
</p>
<dl>
<dt>0</dt>
<dd>
Zero is not a valid OpenFlow port number.
</dd>
<dt><code>OFPP_MAX</code> (<code>0xff00</code> or 65,280).</dt>
<dd>
This value has only been clearly specified as a valid port
number as of OpenFlow 1.3.3. Before that, its status was
unclear, and so Open vSwitch has never allowed
<code>OFPP_MAX</code> to be used as a port number, so
packets will never be received on this port. (Other
OpenFlow switches, of course, might use it.)
</dd>
<dt><code>OFPP_UNSET</code> (<code>0xfff7</code> or 65,527)</dt>
<dt><code>OFPP_IN_PORT</code> (<code>0xfff8</code> or 65,528)</dt>
<dt><code>OFPP_TABLE</code> (<code>0xfff9</code> or 65,529)</dt>
<dt><code>OFPP_NORMAL</code> (<code>0xfffa</code> or 65,530)</dt>
<dt><code>OFPP_FLOOD</code> (<code>0xfffb</code> or 65,531)</dt>
<dt><code>OFPP_ALL</code> (<code>0xfffc</code> or 65,532)</dt>
<dd>
<p>
These port numbers are used only in output actions and never
appear as ingress ports.
</p>
<p>
Most of these port numbers were defined in OpenFlow 1.0, but
<code>OFPP_UNSET</code> was only introduced in OpenFlow 1.5.
</p>
</dd>
</dl>
<p>
Values that will never appear when receiving a packet may
still be matched against in the flow table. There are still
circumstances in which those flows can be matched:
</p>
<ul>
<li>
The <code>resubmit</code> Open vSwitch extension action allows a
flow table lookup with an arbitrary ingress port.
</li>
<li>
An action that modifies the ingress port field (see below),
such as e.g. <code>load</code> or <code>set_field</code>,
followed by an action or instruction that performs another
flow table lookup, such as <code>resubmit</code> or
<code>goto_table</code>.
</li>
</ul>
<p>
This field is heavily used for matching in OpenFlow tables,
but for packet egress, it has only very limited roles:
</p>
<ul>
<li>
<p>
OpenFlow requires suppressing output actions to <ref
field="in_port"/>. That is, the following two flows both drop all
packets that arrive on port 1:
</p>
<pre>
in_port=1,actions=1
in_port=1,actions=drop
</pre>
<p>
(This behavior is occasionally useful for flooding to a
subset of ports. Specifying <code>actions=1,2,3,4</code>,
for example, outputs to ports 1, 2, 3, and 4, omitting the
ingress port.)
</p>
</li>
<li>
OpenFlow has a special port <code>OFPP_IN_PORT</code> (with
value 0xfff8) that outputs to the ingress port. For example,
in a switch that has four ports numbered 1 through 4,
<code>actions=1,2,3,4,in_port</code> outputs to ports 1, 2,
3, and 4, including the ingress port.
</li>
</ul>
<p>
Because the ingress port field has so little influence on packet
processing, it does not ordinarily make sense to modify the
ingress port field. The field is writable only to support the
occasional use case where the ingress port's roles in packet
egress, described above, become troublesome. For example,
<code>actions=load:0->NXM_OF_IN_PORT[],output:123</code>
will output to port 123 regardless of whether it is in the
ingress port. If the ingress port is important, then one may save
and restore it on the stack:
</p>
<pre>
actions=push:NXM_OF_IN_PORT[],load:0->NXM_OF_IN_PORT[],output:123,pop:NXM_OF_IN_PORT[]
</pre>
<p>
or, in Open vSwitch 2.7 or later, use the <code>clone</code> action to
save and restore it:
</p>
<pre>
actions=clone(load:0->NXM_OF_IN_PORT[],output:123)
</pre>
<p>
The ability to modify the ingress port is an Open vSwitch
extension to OpenFlow.
</p>
</field>
<field id="MFF_IN_PORT_OXM" title="OXM Ingress Port">
<p>
OpenFlow 1.1 and later use a 32-bit port number, so this field
supplies a 32-bit view of the ingress port. Current versions of
Open vSwitch support only a 16-bit range of ports:
</p>
<ul>
<li>
OpenFlow 1.0 ports <code>0x0000</code> to
<code>0xfeff</code>, inclusive, map to OpenFlow 1.1
port numbers with the same values.
</li>
<li>
OpenFlow 1.0 ports <code>0xff00</code> to
<code>0xffff</code>, inclusive, map to OpenFlow 1.1 port
numbers <code>0xffffff00</code> to <code>0xffffffff</code>.
</li>
<li>
OpenFlow 1.1 ports <code>0x0000ff00</code> to
<code>0xfffffeff</code> are not mapped and not supported.
</li>
</ul>
<p>
<ref field="in_port"/> and <ref field="in_port_oxm"/> are two views of
the same information, so all of the comments on <ref field="in_port"/>
apply to <ref field="in_port_oxm"/> too. Modifying <ref
field="in_port"/> changes <ref field="in_port_oxm"/>, and vice versa.
</p>
<p>
Setting <ref field="in_port_oxm"/> to an unsupported value yields
unspecified behavior.
</p>
</field>
<field id="MFF_SKB_PRIORITY" title="Output Queue">
<p>
<b>Future Directions:</b> Open vSwitch implements the output queue as a
field, but does not currently expose it through OXM or NXM for matching
purposes. If this turns out to be a useful feature, it could be
implemented in future versions. Only the <code>set_queue</code>,
<code>enqueue</code>, and <code>pop_queue</code> actions currently
influence the output queue.
</p>
<p>
This field influences how packets in the flow will be queued,
for quality of service (QoS) purposes, when they egress the
switch. Its range of meaningful values, and their meanings,
varies greatly from one OpenFlow implementation to another.
Even within a single implementation, there is no guarantee
that all OpenFlow ports have the same queues configured or
that all OpenFlow ports in an implementation can be configured
the same way queue-wise.
</p>
<p>
Configuring queues on OpenFlow is not well standardized. On
Linux, Open vSwitch supports queue configuration via OVSDB,
specifically the <code>QoS</code> and <code>Queue</code>
tables (see <code>ovs-vswitchd.conf.db(5)</code> for details).
Ports of Open vSwitch to other platforms might require queue
configuration through some separate protocol (such as a CLI).
Even on Linux, Open vSwitch exposes only a fraction of the
kernel's queuing features through OVSDB, so advanced or
unusual uses might require use of separate utilities
(e.g. <code>tc</code>). OpenFlow switches other than Open
vSwitch might use OF-CONFIG or any of the configuration
methods mentioned above. Finally, some OpenFlow switches have
a fixed number of fixed-function queues (e.g. eight queues
with strictly defined priorities) and others do not support
any control over queuing.
</p>
<p>
The only output queue that all OpenFlow implementations must
support is zero, to identify a default queue, whose properties
are implementation-defined. Outputting a packet to a queue
that does not exist on the output port yields unpredictable
behavior: among the possibilities are that the packet might be
dropped or transmitted with a very high or very low priority.
</p>
<p>
OpenFlow 1.0 only allowed output queues to be specified as part of an
<code>enqueue</code> action that specified both a queue and an output
port. That is, OpenFlow 1.0 treats the queue as an argument to an
action, not as a field.
</p>
<p>
To increase flexibility, OpenFlow 1.1 added an action to set the output
queue. This model was carried forward, without change, through
OpenFlow 1.5.
</p>
<p>
Open vSwitch implements the native queuing model of each
OpenFlow version it supports. Open vSwitch also includes an
extension for setting the output queue as an action in
OpenFlow 1.0.
</p>
<p>
When a packet ingresses into an OpenFlow switch, the output
queue is ordinarily set to 0, indicating the default queue.
However, Open vSwitch supports various ways to forward a
packet from one OpenFlow switch to another within a single
host. In these cases, Open vSwitch maintains the output queue
across the forwarding step. For example:
</p>
<ul>
<li>
A hop across an Open vSwitch ``patch port'' (which does not
actually involve queuing) preserves the output queue.
</li>
<li>
<p>
When a flow sets the output queue then outputs to an
OpenFlow tunnel port, the encapsulation preserves the
output queue. If the kernel TCP/IP stack routes the
encapsulated packet directly to a physical interface, then
that output honors the output queue. Alternatively, if
the kernel routes the encapsulated packet to another Open
vSwitch bridge, then the output queue set previously
becomes the initial output queue on ingress to the second
bridge and will thus be used for further output actions
(unless overridden by a new ``set queue'' action).
</p>
<p>
(This description reflects the current behavior of Open
vSwitch on Linux. This behavior relies on details of the
Linux TCP/IP stack. It could be difficult to make ports
to other operating systems behave the same way.)
</p>
</li>
</ul>
</field>
<field id="MFF_PKT_MARK" title="Packet Mark">
<p>
Packet mark comes to Open vSwitch from the Linux kernel, in
which the <code>sk_buff</code> data structure that represents
a packet contains a 32-bit member named <code>skb_mark</code>.
The value of <code>skb_mark</code> propagates along with the
packet it accompanies wherever the packet goes in the kernel.
It has no predefined semantics but various kernel-user
interfaces can set and match on it, which makes it suitable
for ``marking'' packets at one point in their handling and
then acting on the mark later. With <code>iptables</code>,
for example, one can mark some traffic specially at ingress
and then handle that traffic differently at egress based on
the marked value.
</p>
<p>
Packet mark is an attempt at a generalization of the
<code>skb_mark</code> concept beyond Linux, at least through more
generic naming. Like <ref field="skb_priority"/>, packet mark is
preserved across forwarding steps within a machine. Unlike <ref
field="skb_priority"/>, packet mark has no direct effect on packet
forwarding: the value set in packet mark does not matter unless some
later OpenFlow table or switch matches on packet mark, or unless the
packet passes through some other kernel subsystem that has been
configured to interpret packet mark in specific ways, e.g. through
<code>iptables</code> configuration mentioned above.
</p>
<p>
Preserving packet mark across kernel forwarding steps relies
heavily on kernel support, which ports to non-Linux operating
systems may not have. Regardless of operating system support,
Open vSwitch supports packet mark within a single bridge and
across patch ports.
</p>
<p>
The value of packet mark when a packet ingresses into the
first Open vSwich bridge is typically zero, but it could be
nonzero if its value was previously set by some kernel
subsystem.
</p>
</field>
<field id="MFF_ACTSET_OUTPUT" title="Action Set Output Port">
<p>
Holds the output port currently in the OpenFlow action set (i.e. from
an <code>output</code> action within a <code>write_actions</code>
instruction). Its value is an OpenFlow port number. If there is no
output port in the OpenFlow action set, or if the output port will be
ignored (e.g. because there is an output group in the OpenFlow action
set), then the value will be <code>OFPP_UNSET</code>.
</p>
<p>
Open vSwitch allows any table to match this field. OpenFlow, however,
only requires this field to be matchable from within an OpenFlow egress
table (a feature that Open vSwitch does not yet implement).
</p>
</field>
<field id="MFF_DP_HASH" title="Datapath Hash" internal="yes"/>
<field id="MFF_RECIRC_ID" title="Datapath Recirculation ID" internal="yes"/>
</group>
<group title="Connection Tracking">
<p>
Open vSwitch 2.5 and later support ``connection tracking,'' which allows
bidirectional streams of packets to be statefully grouped into
connections. Open vSwitch connection tracking, for example, identifies
the patterns of TCP packets that indicates a successfully initiated
connection, as well as those that indicate that a connection has been
torn down. Open vSwitch connection tracking can also identify related
connections, such as FTP data connections spawned from FTP control
connections.
</p>
<p>
An individual packet passing through the pipeline may be in one of two
states, ``untracked'' or ``tracked,'' which may be distinguished via the
``trk'' flag in <ref field="ct_state"/>. A packet is
<dfn>untracked</dfn> at the beginning of the Open vSwitch pipeline and
continues to be untracked until the pipeline invokes the <code>ct</code>
action. The connection tracking fields are all zeroes in an untracked
packet. When a flow in the Open vSwitch pipeline invokes the
<code>ct</code> action, the action initializes the connection tracking
fields and the packet becomes <dfn>tracked</dfn> for the remainder of its
processing.
</p>
<p>
The connection tracker stores connection state in an internal table, but
it only adds a new entry to this table when a <code>ct</code> action for
a new connection invokes <code>ct</code> with the <code>commit</code>
parameter. For a given connection, when a pipeline has executed
<code>ct</code>, but not yet with <code>commit</code>, the connection is
said to be <dfn>uncommitted</dfn>. State for an uncommitted connection
is ephemeral and does not persist past the end of the pipeline, so some
features are only available to committed connections. A connection would
typically be left uncommitted as a way to drop its packets.
</p>
<p>
Connection tracking is an Open vSwitch extension to OpenFlow.
</p>
<field id="MFF_CT_STATE" title="Connection Tracking State">
<p>
This field holds several flags that can be used to determine the state
of the connection to which the packet belongs.
</p>
<p>
Matches on this field are most conveniently written in terms of
symbolic names (listed below), each preceded by either <code>+</code>
for a flag that must be set, or <code>-</code> for a flag that must be
unset, without any other delimiters between the flags. Flags not
mentioned are wildcarded. For example,
<code>tcp,ct_state=+trk-new</code> matches TCP packets that have been
run through the connection tracker and do not establish a new
connection. Matches can also be written as
<code><var>flags</var>/<var>mask</var></code>, where <var>flags</var>
and <var>mask</var> are 32-bit numbers in decimal or in hexadecimal
prefixed by <code>0x</code>.
</p>
<p>
The following flags are defined:
</p>
<dl>
<dt><code>new</code> (0x01)</dt>
<dd>
A new connection. Set to 1 if this is an uncommitted connection.
</dd>
<dt><code>est</code> (0x02)</dt>
<dd>
Part of an existing connection. Set to 1 if this is a committed
connection.
</dd>
<dt><code>rel</code> (0x04)</dt>
<dd>
<p>
Related to an existing connection, e.g. an ICMP ``destination
unreachable'' message or an FTP data connections. This flag will
only be 1 if the connection to which this one is related is
committed.
</p>
<p>
Connections identified as <code>rel</code> are separate from the
originating connection and must be committed separately. All
packets for a related connection will have the <code>rel</code>
flag set, not just the initial packet.
</p>
</dd>
<dt><code>rpl</code> (0x08)</dt>
<dd>
This packet is in the reply direction, meaning that it is in the
opposite direction from the packet that initiated the connection.
This flag will only be 1 if the connection is committed.
</dd>
<dt><code>inv</code> (0x10)</dt>
<dd>
<p>
The state is invalid, meaning that the connection tracker couldn't
identify the connection. This flag is a catch-all for problems
in the connection or the connection tracker, such as:
</p>
<ul>
<li>
L3/L4 protocol handler is not loaded/unavailable. With the Linux
kernel datapath, this may mean that the
<code>nf_conntrack_ipv4</code> or <code>nf_conntrack_ipv6</code>
modules are not loaded.
</li>
<li>
L3/L4 protocol handler determines that the packet is malformed.
</li>
<li>
Packets are unexpected length for protocol.
</li>
</ul>
</dd>
<dt><code>trk</code> (0x20)</dt>
<dd>
This packet is tracked, meaning that it has previously traversed the
connection tracker. If this flag is not set, then no other flags
will be set. If this flag is set, then the packet is tracked and
other flags may also be set.
</dd>
<dt><code>snat</code> (0x40)</dt>
<dd>
This packet was transformed by source address/port translation by a
preceding <code>ct</code> action. Open vSwitch 2.6 added this flag.
</dd>
<dt><code>dnat</code> (0x80)</dt>
<dd>
This packet was transformed by destination address/port translation
by a preceding <code>ct</code> action. Open vSwitch 2.6 added this
flag.
</dd>
</dl>
<p>
There are additional constraints on these flags, listed in decreasing
order of precedence below:
</p>
<ol>
<li>
If <code>trk</code> is unset, no other flags are set.
</li>
<li>
If <code>trk</code> is set, one or more other flags may be set.
</li>
<li>
If <code>inv</code> is set, only the <code>trk</code> flag is also
set.
</li>
<li>
<code>new</code> and <code>est</code> are mutually exclusive.
</li>
<li>
<code>new</code> and <code>rpl</code> are mutually exclusive.
</li>
<li>
<code>rel</code> may be set in conjunction with any other flags.
</li>
</ol>
<p>
Future versions of Open vSwitch may define new flags.
</p>
</field>
<field id="MFF_CT_ZONE" title="Connection Tracking Zone">
A connection tracking zone, the zone value passed to the most recent
<code>ct</code> action. Each zone is an independent connection tracking
context, so tracking the same packet in multiple contexts requires using
the <code>ct</code> action multiple times.
</field>
<field id="MFF_CT_MARK" title="Connection Tracking Mark">
The metadata committed, by an action within the <code>exec</code>
parameter to the <code>ct</code> action, to the connection to which the
current packet belongs.
</field>
<field id="MFF_CT_LABEL" title="Connection Tracking Label">
The label committed, by an action within the <code>exec</code>
parameter to the <code>ct</code> action, to the connection to which the
current packet belongs.
</field>
<p>
Open vSwitch 2.8 introduced the matching support for connection
tracker original direction 5-tuple fields.
</p>
<p>
For non-committed non-related connections the conntrack original
direction tuple fields always have the same values as the
corresponding headers in the packet itself. For any other packets of
a committed connection the conntrack original direction tuple fields
reflect the values from that initial non-committed non-related packet,
and thus may be different from the actual packet headers, as the
actual packet headers may be in reverse direction (for reply packets),
transformed by NAT (when \fBnat\fR option was applied to the
connection), or be of different protocol (i.e., when an ICMP response
is sent to an UDP packet). In case of related connections, e.g., an
FTP data connection, the original direction tuple contains the
original direction headers from the master connection, e.g., an FTP
control connection.
</p>
<p>
The following fields are populated by the ct action, and require a
match to a valid connection tracking state as a prerequisite, in
addition to the IP or IPv6 ethertype match. Examples of valid
connection tracking state matches include \fBct_state=+new\fR,
\fBct_state=+est\fR, \fBct_state=+rel\fR, and \fBct_state=+trk-inv\fR.
</p>
<field id="MFF_CT_NW_SRC" title="Connection Tracking Original Direction IPv4 Source Address">
Matches IPv4 conntrack original direction tuple source address.
See the paragraphs above for general description to the
conntrack original direction tuple. Introduced in Open vSwitch
2.8.
</field>
<field id="MFF_CT_NW_DST" title="Connection Tracking Original Direction IPv4 Destination Address">
Matches IPv4 conntrack original direction tuple destination address.
See the paragraphs above for general description to the
conntrack original direction tuple. Introduced in Open vSwitch
2.8.
</field>
<field id="MFF_CT_IPV6_SRC" title="Connection Tracking Original Direction IPv6 Source Address">
Matches IPv6 conntrack original direction tuple source address.
See the paragraphs above for general description to the
conntrack original direction tuple. Introduced in Open vSwitch
2.8.
</field>
<field id="MFF_CT_IPV6_DST" title="Connection Tracking Original Direction IPv6 Destination Address">
Matches IPv6 conntrack original direction tuple destination address.
See the paragraphs above for general description to the
conntrack original direction tuple. Introduced in Open vSwitch
2.8.
</field>
<field id="MFF_CT_NW_PROTO" title="Connection Tracking Original Direction IP Protocol">
Matches conntrack original direction tuple IP protocol type,
which is specified as a decimal number between 0 and 255,
inclusive (e.g. 1 to match ICMP packets or 6 to match TCP
packets). In case of, for example, an ICMP response to an UDP
packet, this may be different from the IP protocol type of the
packet itself. See the paragraphs above for general description
to the conntrack original direction tuple. Introduced in Open
vSwitch 2.8.
</field>
<field id="MFF_CT_TP_SRC" title="Connection Tracking Original Direction Transport Layer Source Port">
Bitwise match on the conntrack original direction tuple
transport source, when
<code>MFF_CT_NW_PROTO</code> has value 6 for TCP, 17 for UDP, or
132 for SCTP. When <code>MFF_CT_NW_PROTO</code> has value 1 for
ICMP, or 58 for ICMPv6, the lower 8 bits of
<code>MFF_CT_TP_SRC</code> matches the conntrack original
direction ICMP type. See the paragraphs above for general
description to the conntrack original direction
tuple. Introduced in Open vSwitch 2.8.
</field>
<field id="MFF_CT_TP_DST" title="Connection Tracking Original Direction Transport Layer Source Port">
Bitwise match on the conntrack original direction tuple
transport destination port, when
<code>MFF_CT_NW_PROTO</code> has value 6 for TCP, 17 for UDP, or
132 for SCTP. When <code>MFF_CT_NW_PROTO</code> has value 1 for
ICMP, or 58 for ICMPv6, the lower 8 bits of
<code>MFF_CT_TP_DST</code> matches the conntrack original
direction ICMP code. See the paragraphs above for general
description to the conntrack original direction
tuple. Introduced in Open vSwitch 2.8.
</field>
</group>
<group title="Register">
<p>
These fields give an OpenFlow switch space for temporary storage while
the pipeline is running. Whereas metadata fields can have a meaningful
initial value and can persist across some hops across OpenFlow switches,
registers are always initially 0 and their values never persist across
inter-switch hops (not even across patch ports).
</p>
<field id="MFF_METADATA" title="OpenFlow Metadata">
<p>
This field is the oldest standardized OpenFlow register field,
introduced in OpenFlow 1.1. It was introduced to model the limited
number of user-defined bits that some ASIC-based switches can carry
through their pipelines. Because of hardware limitations, OpenFlow
allows switches to support writing and masking only an
implementation-defined subset of bits, even no bits at all. The Open
vSwitch software switch always supports all 64 bits, but of course an
Open vSwitch port to an ASIC would have the same restriction as the
ASIC itself.
</p>
<p>
This field has an OXM code point, but OpenFlow 1.4 and earlier allow it
to be modified only with a specialized instruction, not with a
``set-field'' action. OpenFlow 1.5 removes this restriction. Open
vSwitch does not enforce this restriction, regardless of OpenFlow
version.
</p>
</field>
<field id="MFF_REG0" title="Register 0">
This is the first of several Open vSwitch registers, all of which have
the same properties. Open vSwitch 1.1 introduced registers 0, 1, 2, and
3, version 1.3 added register 4, version 1.7 added registers 5, 6, and 7,
and version 2.6 added registers 8 through 15.
</field>
<!-- XXX series -->
<field id="MFF_REG1" title="Register 1" hidden="yes"/>
<field id="MFF_REG2" title="Register 2" hidden="yes"/>
<field id="MFF_REG3" title="Register 3" hidden="yes"/>
<field id="MFF_REG4" title="Register 4" hidden="yes"/>
<field id="MFF_REG5" title="Register 5" hidden="yes"/>
<field id="MFF_REG6" title="Register 6" hidden="yes"/>
<field id="MFF_REG7" title="Register 7" hidden="yes"/>
<field id="MFF_REG8" title="Register 8" hidden="yes"/>
<field id="MFF_REG9" title="Register 9" hidden="yes"/>
<field id="MFF_REG10" title="Register 10" hidden="yes"/>
<field id="MFF_REG11" title="Register 11" hidden="yes"/>
<field id="MFF_REG12" title="Register 12" hidden="yes"/>
<field id="MFF_REG13" title="Register 13" hidden="yes"/>
<field id="MFF_REG14" title="Register 14" hidden="yes"/>
<field id="MFF_REG15" title="Register 15" hidden="yes"/>
<field id="MFF_XREG0" title="Extended Register 0">
<p>
This is the first of the registers introduced in OpenFlow 1.5.
OpenFlow 1.5 calls these fields just the ``packet registers,'' but Open
vSwitch already had 32-bit registers by that name, so Open vSwitch uses
the name ``extended registers'' in an attempt to reduce confusion. The
standard allows for up to 128 registers, each 64 bits wide, but Open
vSwitch only implements 4 (in versions 2.4 and 2.5) or 8 (in version
2.6 and later).
</p>
<p>
Each of the 64-bit extended registers overlays two of the 32-bit
registers: <code>xreg0</code> overlays <code>reg0</code> and
<code>reg1</code>, with <code>reg0</code> supplying the
most-significant bits of <code>xreg0</code> and <code>reg1</code> the
least-significant. Similarly, <code>xreg1</code> overlays
<code>reg2</code> and <code>reg3</code>, and so on.
</p>
<p>
The OpenFlow specification says, ``In most cases, the packet registers
can not be matched in tables, i.e. they usually can not be used in the
flow entry match structure'' [OpenFlow 1.5, section 7.2.3.10], but
there is no reason for a software switch to impose such a restriction,
and Open vSwitch does not.
</p>
</field>
<!-- XXX series -->
<field id="MFF_XREG1" title="Extended Register 1" hidden="yes"/>
<field id="MFF_XREG2" title="Extended Register 2" hidden="yes"/>
<field id="MFF_XREG3" title="Extended Register 3" hidden="yes"/>
<field id="MFF_XREG4" title="Extended Register 4" hidden="yes"/>
<field id="MFF_XREG5" title="Extended Register 5" hidden="yes"/>
<field id="MFF_XREG6" title="Extended Register 6" hidden="yes"/>
<field id="MFF_XREG7" title="Extended Register 7" hidden="yes"/>
<field id="MFF_XXREG0" title="Double-Extended Register 0">
<p>
This is the first of the double-extended registers introduce in Open
vSwitch 2.6. Each of the 128-bit extended registers overlays four of
the 32-bit registers: <code>xxreg0</code> overlays <code>reg0</code>
through <code>reg3</code>, with <code>reg0</code> supplying the
most-significant bits of <code>xxreg0</code> and <code>reg3</code> the
least-significant. <code>xxreg1</code> similarly overlays
<code>reg4</code> through <code>reg7</code>, and so on.
</p>
</field>
<!-- XXX series -->
<field id="MFF_XXREG1" title="Double-Extended Register 1" hidden="yes"/>
<field id="MFF_XXREG2" title="Double-Extended Register 2" hidden="yes"/>
<field id="MFF_XXREG3" title="Double-Extended Register 3" hidden="yes"/>
</group>
<group title="Layer 2 (Ethernet)">
<p>
Ethernet is the only layer-2 protocol that Open vSwitch
supports. As with most software, Open vSwitch and OpenFlow
regard an Ethernet frame to begin with the 14-byte header and
end with the final byte of the payload; that is, the frame check
sequence is not considered part of the frame.
</p>
<field id="MFF_ETH_SRC" title="Ethernet Source">
<p>
The Ethernet source address:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width=".75"/>
<bits name="src" above="48" width=".75" fill="yes"/>
<bits name="type" above="16" width="0.4"/>
</header>
<dots/>
</diagram>
</field>
<field id="MFF_ETH_DST" title="Ethernet Destination">
<p>
The Ethernet destination address:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width=".75" fill="yes"/>
<bits name="src" above="48" width=".75"/>
<bits name="type" above="16" width="0.4"/>
</header>
<dots/>
</diagram>
<p>
Open vSwitch 1.8 and later support arbitrary masks for source and/or
destination. Earlier versions only support masking the destination
with the following masks:
</p>
<dl>
<dt><code>01:00:00:00:00:00</code></dt>
<dd>
Match only the multicast bit. Thus,
<code>dl_dst=01:00:00:00:00:00/01:00:00:00:00:00</code> matches all
multicast (including broadcast) Ethernet packets, and
<code>dl_dst=00:00:00:00:00:00/01:00:00:00:00:00</code> matches all
unicast Ethernet packets.
</dd>
<dt><code>fe:ff:ff:ff:ff:ff</code></dt>
<dd>
Match all bits except the multicast bit. This is probably not
useful.
</dd>
<dt><code>ff:ff:ff:ff:ff:ff</code></dt>
<dd>
Exact match (equivalent to omitting the mask).
</dd>
<dt><code>00:00:00:00:00:00</code></dt>
<dd>
Wildcard all bits (equivalent to <code>dl_dst=*</code>).
</dd>
</dl>
</field>
<field id="MFF_ETH_TYPE" title="Ethernet Type">
<p>
The most commonly seen Ethernet frames today use a format
called ``Ethernet II,'' in which the last two bytes of the
Ethernet header specify the Ethertype. For such a frame, this
field is copied from those bytes of the header, like so:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width=".75"/>
<bits name="src" above="48" width=".75"/>
<bits name="type" above="16" below="\[>=]0x600" width="0.4" fill="yes"/>
</header>
<dots/>
</diagram>
<p>
Every Ethernet type has a value 0x600 (1,536) or greater.
When the last two bytes of the Ethernet header have a value
too small to be an Ethernet type, then the value found there
is the total length of the frame in bytes, excluding the
Ethernet header. An 802.2 LLC header typically follows the
Ethernet header. OpenFlow and Open vSwitch only support LLC
headers with DSAP and SSAP <code>0xaa</code> and control byte
<code>0x03</code>, which indicate that a SNAP header follows
the LLC header. In turn, OpenFlow and Open vSwitch only
support a SNAP header with organization <code>0x000000</code>.
In such a case, this field is copied from the type field in
the SNAP header, like this:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width=".75"/>
<bits name="src" above="48" width=".75"/>
<bits name="type" above="16" below="<0x600" width="0.4"/>
</header>
<header name="LLC">
<bits name="DSAP" above="8" below="0xaa" width=".4"/>
<bits name="SSAP" above="8" below="0xaa" width=".4"/>
<bits name="cntl" above="8" below="0x03" width=".4"/>
</header>
<header name="SNAP">
<bits name="org" above="24" below="0x000000" width=".75"/>
<bits name="type" above="16" below="\[>=]0x600" width=".4" fill="yes"/>
</header>
<dots/>
</diagram>
<p>
When an 802.1Q header is inserted after the Ethernet source
and destination, this field is populated with the encapsulated
Ethertype, not the 802.1Q Ethertype. With an Ethernet II
inner frame, the result looks like this:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width=".75"/>
<bits name="src" above="48" width=".75"/>
</header>
<header name="802.1Q">
<bits name="TPID" above="16" below="0x8100" width=".4"/>
<bits name="TCI" above="16" width=".4"/>
</header>
<header name="Ethertype">
<bits name="type" above="16" below="\[>=]0x600" width=".4" fill="yes"/>
</header>
<dots/>
</diagram>
<p>
LLC and SNAP encapsulation look like this with an 802.1Q header:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width=".75"/>
<bits name="src" above="48" width=".75"/>
</header>
<header name="802.1Q">
<bits name="TPID" above="16" below="0x8100" width=".4"/>
<bits name="TCI" above="16" width=".4"/>
</header>
<header name="Ethertype">
<bits name="type" above="16" below="<0x600" width="0.4"/>
</header>
<header name="LLC">
<bits name="DSAP" above="8" below="0xaa" width=".4"/>
<bits name="SSAP" above="8" below="0xaa" width=".4"/>
<bits name="cntl" above="8" below="0x03" width=".4"/>
</header>
<header name="SNAP">
<bits name="org" above="24" below="0x000000" width=".75"/>
<bits name="type" above="16" below="\[>=]0x600" width=".4" fill="yes"/>
</header>
<dots/>
</diagram>
<p>
When a packet doesn't match any of the header formats described
above, Open vSwitch and OpenFlow set this field to
<code>0x5ff</code> (<code>OFP_DL_TYPE_NOT_ETH_TYPE</code>).
</p>
</field>
</group>
<group title="VLAN">
<p>
The 802.1Q VLAN header causes more trouble than any other 4
bytes in networking. OpenFlow 1.0, 1.1, and 1.2+ all treat VLANs
differently. Open vSwitch extensions add another variant to the mix.
Open vSwitch reconciles all four treatments as best it can.
</p>
<h2>VLAN Header Format</h2>
<p>
An 802.1Q VLAN header consists of two 16-bit fields:
</p>
<diagram>
<header name="TPID">
<bits name="Ethertype" above="16" below="0x8100" width="1.8"/>
</header>
<nospace/>
<header name="TCI">
<bits name="PCP" above="3" width=".6"/>
<bits name="CFI" above="1" below="0" width=".3"/>
<bits name="VID" above="12" width=".9"/>
</header>
</diagram>
<p>
The first 16 bits of the VLAN header, the <dfn>TPID</dfn> (Tag Protocol
IDentifier), is an Ethertype. When the VLAN header is inserted just
after the source and destination MAC addresses in a Ethertype frame, the
TPID serves to identify the presence of the VLAN. The standard TPID, the
only one that Open vSwitch supports, is <code>0x8100</code>. OpenFlow
1.0 explicitly supports only TPID <code>0x8100</code>. OpenFlow 1.1, but
not earlier or later versions, also requires support for TPID
<code>0x88a8</code> (Open vSwitch does not support this). OpenFlow 1.2
through 1.5 do not require support for specific TPIDs (the ``push vlan
header'' action does say that only <code>0x8100</code> and
<code>0x88a8</code> should be pushed). No version of OpenFlow provides a
way to distinguish or match on the TPID.
</p>
<p>
The remaining 16 bits of the VLAN header, the <dfn>TCI</dfn>
(Tag Control Information), is subdivided into three subfields:
</p>
<ul>
<li>
<dfn>PCP</dfn> (Priority Control Point), is a 3-bit 802.1p
<dfn>priority</dfn>. The lowest priority is value 1, the
second-lowest is value 0, and priority increases from 2 up to
highest priority 7.
</li>
<li>
<p>
<dfn>CFI</dfn> (Canonical Format Indicator), is a 1-bit field. On an
Ethernet network, its value is always 0. This led to it later being
repurposed under the name <dfn>DEI</dfn> (Drop Eligibility
Indicator). By either name, OpenFlow and Open vSwitch don't provide
any way to match or set this bit.
</p>
</li>
<li>
<dfn>VID</dfn> (VLAN IDentifier), is a 12-bit VLAN. If the
VID is 0, then the frame is not part of a VLAN. In that case,
the VLAN header is called a <dfn>priority tag</dfn> because it
is only meaningful for assigning the frame a priority. VID
<code>0xfff</code> (4,095) is reserved.
</li>
</ul>
<p>
See <ref field="eth_type"/> for illustrations of a complete Ethernet
frame with 802.1Q tag included.
</p>
<h2>Multiple VLANs</h2>
<p>
Open vSwitch can match only a single VLAN header. If more than
one VLAN header is present, then <ref field="eth_type"/>
holds the TPID of the inner VLAN header. Open vSwitch stops
parsing the packet after the inner TPID, so matching further
into the packet (e.g. on the inner TCI or L3 fields) is not
possible.
</p>
<p>
OpenFlow only directly supports matching a single VLAN header. In
OpenFlow 1.1 or later, one OpenFlow table can match on the outermost VLAN
header and pop it off, and a later OpenFlow table can match on the next
outermost header. Open vSwitch does not support this.
</p>
<h2>VLAN Field Details</h2>
<p>
The four variants have three different levels of expressiveness: OpenFlow
1.0 and 1.1 VLAN matching are less powerful than OpenFlow 1.2+ VLAN
matching, which is less powerful than Open vSwitch extension VLAN
matching.
</p>
<h2>OpenFlow 1.0 VLAN Fields</h2>
<p>
OpenFlow 1.0 uses two fields, called <code>dl_vlan</code> and
<code>dl_vlan_pcp</code>, each of which can be either exact-matched or
wildcarded, to specify VLAN matches:
</p>
<ul>
<li>
When both <code>dl_vlan</code> and <code>dl_vlan_pcp</code> are
wildcarded, the flow matches packets without an 802.1Q header or
with any 802.1Q header.
</li>
<li>
The match <code>dl_vlan=0xffff</code> causes a flow to match only
packets without an 802.1Q header. Such a flow should also wildcard
<code>dl_vlan_pcp</code>, since a packet without an 802.1Q header does
not have a PCP. OpenFlow does not specify what to do if a match on PCP
is actually present, but Open vSwitch ignores it.
</li>
<li>
<p>
Otherwise, the flow matches only packets with an 802.1Q
header. If <code>dl_vlan</code> is not wildcarded, then the
flow only matches packets with the VLAN ID specified in
<code>dl_vlan</code>'s low 12 bits. If
<code>dl_vlan_pcp</code> is not wildcarded, then the flow
only matches packets with the priority specified in
<code>dl_vlan_pcp</code>'s low 3 bits.
</p>
<p>
OpenFlow does not specify how to interpret the high 4 bits of
<code>dl_vlan</code> or the high 5 bits of <code>dl_vlan_pcp</code>.
Open vSwitch ignores them.
</p>
</li>
</ul>
<field id="MFF_DL_VLAN" title="OpenFlow 1.0 VLAN ID" hidden="yes"/>
<field id="MFF_DL_VLAN_PCP" title="OpenFlow 1.0 VLAN Priority"
hidden="yes"/>
<h2>OpenFlow 1.1 VLAN Fields</h2>
<p>
VLAN matching in OpenFlow 1.1 is similar to OpenFlow 1.0.
The one refinement is that when <code>dl_vlan</code> matches on
<code>0xfffe</code> (<code>OFVPID_ANY</code>), the flow matches
only packets with an 802.1Q header, with any VLAN ID. If
<code>dl_vlan_pcp</code> is wildcarded, the flow matches any
packet with an 802.1Q header, regardless of VLAN ID or priority.
If <code>dl_vlan_pcp</code> is not wildcarded, then the flow
only matches packets with the priority specified in
<code>dl_vlan_pcp</code>'s low 3 bits.
</p>
<p>
OpenFlow 1.1 uses the name <code>OFPVID_NONE</code>, instead of
<code>OFP_VLAN_NONE</code>, for a <code>dl_vlan</code> of
<code>0xffff</code>, but it has the same meaning.
</p>
<p>
In OpenFlow 1.1, Open vSwitch reports error
<code>OFPBMC_BAD_VALUE</code> for an attempt to match on
<code>dl_vlan</code> between 4,096 and <code>0xfffd</code>,
inclusive, or <code>dl_vlan_pcp</code> greater than 7.
</p>
<h2>OpenFlow 1.2 VLAN Fields</h2>
<field id="MFF_VLAN_VID" title="OpenFlow 1.2+ VLAN ID">
<p>
The OpenFlow standard describes this field as consisting of
``12+1'' bits. On ingress, its value is 0 if no 802.1Q header
is present, and otherwise it holds the VLAN VID in its least
significant 12 bits, with bit 12 (<code>0x1000</code> aka
<code>OFPVID_PRESENT</code>) also set to 1. The three most
significant bits are always zero:
</p>
<diagram>
<header name="OXM_OF_VLAN_VID">
<bits name="" above="3" below="0" width=".6"/>
<bits name="P" above="1" width=".1"/>
<bits name="VLAN ID" above="12" width=".9"/>
</header>
</diagram>
<p>
As a consequence of this field's format, one may use it to match the
VLAN ID in all of the ways available with the OpenFlow 1.0 and 1.1
formats, and a few new ways:
</p>
<dl>
<dt>Fully wildcarded</dt>
<dd>
Matches any packet, that is, one without an 802.1Q header or
with an 802.1Q header with any TCI value.
</dd>
<dt>
Value <code>0x0000</code> (<code>OFPVID_NONE</code>), mask
<code>0xffff</code> (or no mask)
</dt>
<dd>
Matches only packets without an 802.1Q header.
</dd>
<dt>
Value <code>0x1000</code>, mask <code>0x1000</code>
</dt>
<dd>
Matches any packet with an 802.1Q header, regardless of VLAN
ID.
</dd>
<dt>
Value <code>0x1009</code>, mask <code>0xffff</code> (or no mask)
</dt>
<dd>
Match only packets with an 802.1Q header with VLAN ID 9.
</dd>
<dt>Value <code>0x1001</code>, mask <code>0x1001</code></dt>
<dd>
Matches only packets that have an 802.1Q header with an
odd-numbered VLAN ID. (This is just an example; one can
match on any desired VLAN ID bit pattern.)
</dd>
</dl>
</field>
<field id="MFF_VLAN_PCP" title="OpenFlow 1.2+ VLAN Priority">
<p>
The 3 least significant bits may be used to match the PCP bits
in an 802.1Q header. Other bits are always zero:
</p>
<diagram>
<header name="OXM_OF_VLAN_VID">
<bits name="zero" above="5" below="0" width="1.0"/>
<bits name="PCP" above="3" width=".6"/>
</header>
</diagram>
<p>
This field may only be used when <ref field="vlan_vid"/> is not
wildcarded and does not exact match on 0 (which only matches
when there is no 802.1Q header).
</p>
<p>
See <cite>VLAN Comparison Chart</cite>, below, for some examples.
</p>
</field>
<h2>Open vSwitch Extension VLAN Field</h2>
<p>
The <ref field="vlan_tci"/> extension can describe more kinds of VLAN
matches than the other variants. It is also simpler than the other
variants.
</p>
<field id="MFF_VLAN_TCI" title="VLAN TCI">
<p>
For a packet without an 802.1Q header, this field is zero. For a
packet with an 802.1Q header, this field is the TCI with the bit in
CFI's position (marked <code>P</code> for ``present'' below) forced to
1. Thus, for a packet in VLAN 9 with priority 7, it has the value
<code>0xf009</code>:
</p>
<diagram>
<header name="NXM_VLAN_TCI">
<bits name="PCP" above="3" below="7" width=".6"/>
<bits name="P" above="1" below="1" width=".2"/>
<bits name="VID" above="12" below="9" width=".9"/>
</header>
</diagram>
<p>
Usage examples:
</p>
<dl>
<dt><code>vlan_tci=0</code></dt>
<dd>
Match packets without an 802.1Q header.
</dd>
<dt><code>vlan_tci=0x1000/0x1000</code></dt>
<dd>
Match packets with an 802.1Q header, regardless of VLAN
and priority values.
</dd>
<dt><code>vlan_tci=0xf123</code></dt>
<dd>
Match packets tagged with priority 7 in VLAN 0x123.
</dd>
<dt><code>vlan_tci=0x1123/0x1fff</code></dt>
<dd>
Match packets tagged with VLAN 0x123 (and any priority).
</dd>
<dt><code>vlan_tci=0x5000/0xf000</code></dt>
<dd>
Match packets tagged with priority 2 (in any VLAN).
</dd>
<dt><code>vlan_tci=0/0xfff</code></dt>
<dd>
Match packets with no 802.1Q header or tagged with VLAN 0
(and any priority).
</dd>
<dt><code>vlan_tci=0x5000/0xe000</code></dt>
<dd>
Match packets with no 802.1Q header or tagged with priority 2 (in any VLAN).
</dd>
<dt><code>vlan_tci=0/0xefff</code></dt>
<dd>
Match packets with no 802.1Q header or tagged with VLAN 0
and priority 0.
</dd>
</dl>
<p>
See <cite>VLAN Comparison Chart</cite>, below, for more examples.
</p>
</field>
<h2>VLAN Comparison Chart</h2>
<p>
The following table describes each of several possible matching
criteria on 802.1Q header may be expressed with each variation
of the VLAN matching fields:
</p>
<tbl>
r r r r r.
Criteria OpenFlow 1.0 OpenFlow 1.1 OpenFlow 1.2+ NXM
\_ \_ \_ \_ \_
[1] \fL????\fR/\fL1\fR,\fL??\fR/\fL?\fR \fL????\fR/\fL1\fR,\fL??\fR/\fL?\fR \fL0000\fR/\fL0000\fR,\fL--\fR \fL0000\fR/\fL0000\fR
[2] \fLffff\fR/\fL0\fR,\fL??\fR/\fL?\fR \fLffff\fR/\fL0\fR,\fL??\fR/\fL?\fR \fL0000\fR/\fLffff\fR,\fL--\fR \fL0000\fR/\fLffff\fR
[3] \fL0xxx\fR/\fL0\fR,\fL??\fR/\fL1\fR \fL0xxx\fR/\fL0\fR,\fL??\fR/\fL1\fR \fL1xxx\fR/\fLffff\fR,\fL--\fR \fL1xxx\fR/\fL1fff\fR
[4] \fL????\fR/\fL1\fR,\fL0y\fR/\fL0\fR \fLfffe\fR/\fL0\fR,\fL0y\fR/\fL0\fR \fL1000\fR/\fL1000\fR,\fL0y\fR \fLz000\fR/\fLf000\fR
[5] \fL0xxx\fR/\fL0\fR,\fL0y\fR/\fL0\fR \fL0xxx\fR/\fL0\fR,\fL0y\fR/\fL0\fR \fL1xxx\fR/\fLffff\fR,\fL0y\fR \fLzxxx\fR/\fLffff\fR
.T&
r r c c r.
[6] (none) (none) \fL1001\fR/\fL1001\fR,\fL--\fR \fL1001\fR/\fL1001\fR
.T&
r r c c c.
[7] (none) (none) (none) \fL3000\fR/\fL3000\fR
[8] (none) (none) (none) \fL0000\fR/\fL0fff\fR
[9] (none) (none) (none) \fL0000\fR/\fLf000\fR
[10] (none) (none) (none) \fL0000\fR/\fLefff\fR
</tbl>
<p>
All numbers in the table are expressed in hexadecimal. The
columns in the table are interpreted as follows:
</p>
<dl>
<dt>Criteria</dt>
<dd>See the list below.</dd>
<dt>OpenFlow 1.0</dt>
<dt>OpenFlow 1.1</dt>
<dd>
<literal>wwww/x,yy/z</literal> means VLAN ID match value
<literal>wwww</literal> with wildcard bit <literal>x</literal>
and VLAN PCP match value <literal>yy</literal> with wildcard
bit <literal>z</literal>. <literal>?</literal> means that the
given bits are ignored (and conventionally
<literal>0</literal> for <literal>wwww</literal> or
<literal>yy</literal>, conventionally <literal>1</literal> for
<literal>x</literal> or <literal>z</literal>). ``(none)''
means that OpenFlow 1.0 (or 1.1) cannot match with these
criteria.
</dd>
<dt>OpenFlow 1.2+</dt>
<dd>
<literal>xxxx/yyyy,zz</literal> means <ref field="vlan_vid"/> with
value <literal>xxxx</literal> and mask <literal>yyyy</literal>, and
<ref field="vlan_pcp"/> (which is not maskable) with value
<literal>zz</literal>. <literal>--</literal> means that <ref
field="vlan_pcp"/> is omitted. ``(none)'' means that OpenFlow 1.2
cannot match with these criteria.
</dd>
<dt>NXM</dt>
<dd>
<literal>xxxx/yyyy</literal> means <ref field="vlan_tci"/> with value
<literal>xxxx</literal> and mask <literal>yyyy</literal>.
</dd>
</dl>
<p>
The matching criteria described by the table are:
</p>
<dl>
<dt>[1]</dt>
<dd>
Matches any packet, that is, one without an 802.1Q header or
with an 802.1Q header with any TCI value.
</dd>
<dt>[2]</dt>
<dd>
<p>
Matches only packets without an 802.1Q header.
</p>
<p>
OpenFlow 1.0 doesn't define the behavior if <ref field="dl_vlan"/> is
set to <code>0xffff</code> and <ref field="dl_vlan_pcp"/> is not
wildcarded. (Open vSwitch always ignores <ref field="dl_vlan_pcp"/>
when <ref field="dl_vlan"/> is set to <code>0xffff</code>.)
</p>
<p>
OpenFlow 1.1 says explicitly to ignore <ref field="dl_vlan_pcp"/>
when <ref field="dl_vlan"/> is set to <code>0xffff</code>.
</p>
<p>
OpenFlow 1.2 doesn't say how to interpret a match with <ref
field="vlan_vid"/> value 0 and a mask with
<code>OFPVID_PRESENT</code> (<code>0x1000</code>) set to 1 and some
other bits in the mask set to 1 also. Open vSwitch interprets it the
same way as a mask of <code>0x1000</code>.
</p>
<p>
Any NXM match with <ref field="vlan_tci"/> value 0 and the CFI bit
set to 1 in the mask is equivalent to the one listed in the table.
</p>
</dd>
<dt>[3]</dt>
<dd>
Matches only packets that have an 802.1Q header with VID
<literal>xxx</literal> (and any PCP).
</dd>
<dt>[4]</dt>
<dd>
<p>
Matches only packets that have an 802.1Q header with PCP
<literal>y</literal> (and any VID).
</p>
<p>
OpenFlow 1.0 doesn't clearly define the behavior for this
case. Open vSwitch implements it this way.
</p>
<p>
In the NXM value, <literal>z</literal> equals
(<literal>y</literal> << 1) | 1.
</p>
</dd>
<dt>[5]</dt>
<dd>
<p>
Matches only packets that have an 802.1Q header with VID
<literal>xxx</literal> and PCP <literal>y</literal>.
</p>
<p>
In the NXM value, <literal>z</literal> equals
(<literal>y</literal> << 1) | 1.
</p>
</dd>
<dt>[6]</dt>
<dd>
Matches only packets that have an 802.1Q header with an
odd-numbered VID (and any PCP). Only possible with OpenFlow
1.2 and NXM. (This is just an example; one can match on any
desired VID bit pattern.)
</dd>
<dt>[7]</dt>
<dd>
Matches only packets that have an 802.1Q header with an
odd-numbered PCP (and any VID). Only possible with NXM.
(This is just an example; one can match on any desired VID bit
pattern.)
</dd>
<dt>[8]</dt>
<dd>
Matches packets with no 802.1Q header or with an 802.1Q header
with a VID of 0. Only possible with NXM.
</dd>
<dt>[9]</dt>
<dd>
Matches packets with no 802.1Q header or with an 802.1Q header
with a PCP of 0. Only possible with NXM.
</dd>
<dt>[10]</dt>
<dd>
Matches packets with no 802.1Q header or with an 802.1Q header
with both VID and PCP of 0. Only possible with NXM.
</dd>
</dl>
</group>
<group title="Layer 2.5: MPLS">
<p>
One or more MPLS headers (more commonly called <dfn>MPLS
labels</dfn>) follow an Ethernet type field that specifies an
MPLS Ethernet type [RFC 3032]. Ethertype <code>0x8847</code> is
used for all unicast. Multicast MPLS is divided into two
specific classes, one of which uses Ethertype
<code>0x8847</code> and the other <code>0x8848</code> [RFC
5332].
</p>
<p>
The most common overall packet format is Ethernet II, shown
below (SNAP encapsulation may be used but is not ordinarily seen
in Ethernet networks):
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.75"/>
<bits name="src" above="48" width="0.75"/>
<bits name="type" above="16" below="0x8847" width="0.4"/>
</header>
<header name="MPLS">
<bits name="label" above="20" width=".6"/>
<bits name="TC" above="3" width=".3"/>
<bits name="S" above="1" width=".1"/>
<bits name="TTL" above="8" width=".4"/>
</header>
<dots/>
</diagram>
<p>
MPLS can be encapsulated inside an 802.1Q header, in which case
the combination looks like this:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width=".75"/>
<bits name="src" above="48" width=".75"/>
</header>
<header name="802.1Q">
<bits name="TPID" above="16" below="0x8100" width=".4"/>
<bits name="TCI" above="16" width=".4"/>
</header>
<header name="Ethertype">
<bits name="type" above="16" below="0x8847" width=".4"/>
</header>
<header name="MPLS">
<bits name="label" above="20" width=".6"/>
<bits name="TC" above="3" width=".3"/>
<bits name="S" above="1" width=".1"/>
<bits name="TTL" above="8" width=".4"/>
</header>
<dots/>
</diagram>
<p>
The fields within an MPLS label are:
</p>
<dl>
<dt>Label, 20 bits.</dt>
<dd>
An identifier.
</dd>
<dt>Traffic control (TC), 3 bits.</dt>
<dd>
Used for quality of service.
</dd>
<dt>Bottom of stack (BOS), 1 bit (labeled just ``S'' above).</dt>
<dd>
<p>
0 indicates that another MPLS label follows this one.
</p>
<p>
1 indicates that this MPLS label is the last one in the
stack, so that some other protocol follows this one.
</p>
</dd>
<dt>Time to live (TTL), 8 bits.</dt>
<dd>
<p>
Each hop across an MPLS network decrements the TTL by 1. If
it reaches 0, the packet is discarded.
</p>
<p>
OpenFlow does not make the MPLS TTL available as a match field, but
actions are available to set and decrement the TTL. Open vSwitch 2.6
and later makes the MPLS TTL available as an extension.
</p>
</dd>
</dl>
<h2>MPLS Label Stacks</h2>
<p>
Unlike the other encapsulations supported by OpenFlow and Open vSwitch,
MPLS labels are routinely used in ``stacks'' two or three deep and
sometimes even deeper. Open vSwitch currently supports up to three
labels.
</p>
<p>
The OpenFlow specification only supports matching on the outermost MPLS
label at any given time. To match on the second label, one must first
``pop'' the outer label and advance to another OpenFlow table, where the
inner label may be matched. To match on the third label, one must pop
the two outer labels, and so on. The Open Networking Foundation is
considering support for directly matching on multiple MPLS labels for
OpenFlow 1.6.<!-- XXX add EXT-* link -->
</p>
<h2>MPLS Inner Protocol</h2>
<p>
Unlike all other forms of encapsulation that Open vSwitch and
OpenFlow support, an MPLS label does not indicate what inner
protocol it encapsulates. Different deployments determine the
inner protocol in different ways [RFC 3032]:
</p>
<ul>
<li>
A few reserved label values do indicate an inner protocol.
Label 0, the ``IPv4 Explicit NULL Label,'' indicates inner
IPv4. Label 2, the ``IPv6 Explicit NULL Label,'' indicates
inner IPv6.
</li>
<li>
Some deployments use a single inner protocol consistently.
</li>
<li>
In some deployments, the inner protocol must be inferred from
the innermost label.
</li>
<li>
In some deployments, the inner protocol must be inferred from
the innermost label and the encapsulated data, e.g. to
distinguish between inner IPv4 and IPv6 based on whether the
first nibble of the inner protocol data are <code>4</code> or
<code>6</code>. OpenFlow and Open vSwitch do not currently
support these cases.
</li>
</ul>
<p>
Open vSwitch and OpenFlow do not infer the inner protocol, even if
reserved label values are in use. Instead, the flow table must specify
the inner protocol at the time it pops the bottommost MPLS label, using
the Ethertype argument to the <code>pop_mpls</code> action.
</p>
<h2>Field Details</h2>
<field id="MFF_MPLS_LABEL" title="MPLS Label">
<p>
The least significant 20 bits hold the ``label'' field from
the MPLS label. Other bits are zero:
</p>
<diagram>
<header name="OXM_OF_MPLS_LABEL">
<bits name="zero" above="12" below="0" width=".6"/>
<bits name="label" above="20" width="1.0"/>
</header>
</diagram>
<p>
Most label values are available for any use by deployments.
Values under 16 are reserved.
</p>
</field>
<field id="MFF_MPLS_TC" title="MPLS Traffic Class">
<p>
The least significant 3 bits hold the TC field from the MPLS
label. Other bits are zero:
</p>
<diagram>
<header name="OXM_OF_MPLS_TC">
<bits name="zero" above="5" below="0" width="1.0"/>
<bits name="TC" above="3" width=".6"/>
</header>
</diagram>
<p>
This field is intended for use for Quality of Service (QoS)
and Explicit Congestion Notification purposes, but its
particular interpretation is deployment specific.
</p>
<p>
Before 2009, this field was named EXP and reserved for
experimental use [RFC 5462].
</p>
</field>
<field id="MFF_MPLS_BOS" title="MPLS Bottom of Stack">
<p>
The least significant bit holds the BOS field from the MPLS
label. Other bits are zero:
</p>
<diagram>
<header name="OXM_OF_MPLS_BOS">
<bits name="zero" above="7" below="0" width="1.3"/>
<bits name="BOS" above="1" width=".3"/>
</header>
</diagram>
<p>
This field is useful as part of processing a series of incoming MPLS
labels. A flow that includes a <code>pop_mpls</code> action should
generally match on <ref field="mpls_bos"/>:
</p>
<ul>
<li>
When <ref field="mpls_bos"/> is 1, there is another MPLS label
following this one, so the Ethertype passed to <code>pop_mpls</code>
should be an MPLS Ethertype. For example: <code>table=0,
dl_type=0x8847, mpls_bos=1, actions=pop_mpls:0x8847,
goto_table:1</code>
</li>
<li>
When <ref field="mpls_bos"/> is 0, this MPLS label is the last one,
so the Ethertype passed to <code>pop_mpls</code> should be a non-MPLS
Ethertype such as IPv4. For example: <code>table=1, dl_type=0x8847,
mpls_bos=0, actions=pop_mpls:0x0800, goto_table:2</code>
</li>
</ul>
</field>
<field id="MFF_MPLS_TTL" title="MPLS Time-to-Live">
<p>
Holds the 8-bit time-to-live field from the MPLS label:
</p>
<diagram>
<header name="NXM_NX_MPLS_TTL">
<bits name="TTL" above="8" width=".4"/>
</header>
</diagram>
</field>
</group>
<group title="Layer 3: IPv4 and IPv6">
<h2>IPv4 Specific Fields</h2>
<p>
These fields are applicable only to IPv4 flows, that is, flows that match
on the IPv4 Ethertype <code>0x0800</code>.
</p>
<field id="MFF_IPV4_SRC" title="IPv4 Source Address">
<p>
The source address from the IPv4 header:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" width="0.4"/>
<bits name="src" above="32" width="0.4" fill="yes"/>
<bits name="dst" above="32" width="0.4"/>
</header>
<dots/>
</diagram>
<p>
For historical reasons, in an ARP or RARP flow, Open vSwitch interprets
matches on <code>nw_src</code> as actually referring to the ARP SPA.
</p>
</field>
<field id="MFF_IPV4_DST" title="IPv4 Destination Address">
<p>
The destination address from the IPv4 header:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" width="0.4"/>
<bits name="src" above="32" width="0.4"/>
<bits name="dst" above="32" width="0.4" fill="yes"/>
</header>
<dots/>
</diagram>
<p>
For historical reasons, in an ARP or RARP flow, Open vSwitch interprets
matches on <code>nw_dst</code> as actually referring to the ARP TPA.
</p>
</field>
<h2>IPv6 Specific Fields</h2>
<p>
These fields apply only to IPv6 flows, that is, flows that match
on the IPv6 Ethertype <code>0x86dd</code>.
</p>
<field id="MFF_IPV6_SRC" title="IPv6 Source Address">
<p>
The source address from the IPv6 header:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x86dd" width="0.4"/>
</header>
<header name="IPv6">
<bits name="..." width="0.4"/>
<bits name="next" above="8" width="0.3"/>
<bits name="src" above="128" width="0.8" fill="yes"/>
<bits name="dst" above="128" width="0.8"/>
</header>
<dots/>
</diagram>
<p>
Open vSwitch 1.8 added support for bitwise matching; earlier versions
supported only CIDR masks.
</p>
</field>
<field id="MFF_IPV6_DST" title="IPv6 Destination Address">
<p>
The destination address from the IPv6 header:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x86dd" width="0.4"/>
</header>
<header name="IPv6">
<bits name="..." width="0.4"/>
<bits name="next" above="8" width="0.3"/>
<bits name="src" above="128" width="0.8"/>
<bits name="dst" above="128" width="0.8" fill="yes"/>
</header>
<dots/>
</diagram>
<p>
Open vSwitch 1.8 added support for bitwise matching; earlier versions
supported only CIDR masks.
</p>
</field>
<field id="MFF_IPV6_LABEL" title="IPv6 Flow Label">
<p>
The least significant 20 bits hold the flow label field from
the IPv6 header. Other bits are zero:
</p>
<diagram>
<header name="OXM_OF_IPV6_FLABEL">
<bits name="zero" above="12" below="0" width=".6"/>
<bits name="label" above="20" width="1.0"/>
</header>
</diagram>
</field>
<h2>IPv4/IPv6 Fields</h2>
<p>
These fields exist with at least approximately the same meaning in both
IPv4 and IPv6, so they are treated as a single field for matching
purposes. Any flow that matches on the IPv4 Ethertype
<code>0x0800</code> or the IPv6 Ethertype <code>0x86dd</code> may match
on these fields.
</p>
<field id="MFF_IP_PROTO" title="IPv4/v6 Protocol">
<p>
Matches the IPv4 or IPv6 protocol type.
</p>
<p>
For historical reasons, in an ARP or RARP flow, Open vSwitch interprets
matches on <code>nw_proto</code> as actually referring to the ARP
opcode. The ARP opcode is a 16-bit field, so for matching purposes ARP
opcodes greater than 255 are treated as 0; this works adequately
because in practice ARP and RARP only use opcodes 1 through 4.
</p>
</field>
<field id="MFF_IP_TTL" title="IPv4/v6 TTL/Hop Limit">
The main reason to match on the TTL or hop limit field is to detect
whether a <code>dec_ttl</code> action will fail due to a TTL exceeded
error. Another way that a controller can detect TTL exceeded is to
listen for <code>OFPR_INVALID_TTL</code> ``packet-in'' messages via
OpenFlow.
</field>
<field id="MFF_IP_FRAG" title="IPv4/v6 Fragment Bitmask">
<p>
Specifies what kinds of IP fragments or non-fragments to match. The
value for this field is most conveniently specified as one of the
following:
</p>
<dl>
<dt><code>no</code></dt>
<dd>
Match only non-fragmented packets.
</dd>
<dt><code>yes</code></dt>
<dd>
Matches all fragments.
</dd>
<dt><code>first</code></dt>
<dd>
Matches only fragments with offset 0.
</dd>
<dt><code>later</code></dt>
<dd>
Matches only fragments with nonzero offset.
</dd>
<dt><code>not_later</code></dt>
<dd>
Matches non-fragmented packets and fragments with zero offset.
</dd>
</dl>
<p>
The field is internally formatted as 2 bits: bit 0 is 1 for an IP
fragment with any offset (and otherwise 0), and bit 1 is 1 for an IP
fragment with nonzero offset (and otherwise 0), like so:
</p>
<diagram>
<header name="NXM_NX_IP_FRAG">
<bits name="zero" above="6" below="0" width=".9"/>
<bits name="later" above="1" width=".3"/>
<bits name="any" above="1" width=".3"/>
</header>
</diagram>
<p>
Even though 2 bits have 4 possible values, this field only uses 3 of
them:
</p>
<ul>
<li>
A packet that is not an IP fragment has value 0.
</li>
<li>
A packet that is an IP fragment with offset 0 (the first fragment)
has bit 0 set and thus value 1.
</li>
<li>
A packet that is an IP fragment with nonzero offset has bits 0 and 1
set and thus value 3.
</li>
</ul>
<p>
The switch may reject matches against values that can never appear.
</p>
<p>
It is important to understand how this field interacts with the
OpenFlow fragment handling mode:
</p>
<ul>
<li>
In <code>OFPC_FRAG_DROP</code> mode, the OpenFlow switch drops all IP
fragments before they reach the flow table, so every packet that is
available for matching will have value 0 in this field.
</li>
<li>
Open vSwitch does not implement <code>OFPC_FRAG_REASM</code> mode,
but if it did then IP fragments would be reassembled before they
reached the flow table and again every packet available for matching
would always have value 0.
</li>
<li>
In <code>OFPC_FRAG_NORMAL</code> mode, all three values are possible,
but OpenFlow 1.0 says that fragments' transport ports are always 0,
even for the first fragment, so this does not provide much extra
information.
</li>
<li>
In <code>OFPC_FRAG_NX_MATCH</code> mode, all three values are
possible. For fragments with offset 0, Open vSwitch makes L4 header
information available.
</li>
</ul>
<p>
Thus, this field is likely to be most useful for an Open vSwitch switch
configured in <code>OFPC_FRAG_NX_MATCH</code> mode. See the
description of the <code>set-frags</code> command in
<code>ovs-ofctl</code>(8), for more details.
</p>
</field>
<h3>IPv4/IPv6 TOS Fields</h3>
<p>
IPv4 and IPv6 contain a one-byte ``type of service'' or TOS field that
has the following format:
</p>
<diagram>
<header name="type of service">
<bits name="DSCP" above="6" width=".9"/>
<bits name="ECN" above="2" width=".3"/>
</header>
</diagram>
<field id="MFF_IP_DSCP" title="IPv4/v6 DSCP (Bits 2-7)">
<p>
This field is the TOS byte with the two ECN bits cleared to 0:
</p>
<diagram>
<header name="NXM_OF_IP_TOS">
<bits name="DSCP" above="6" width=".9"/>
<bits name="zero" above="2" below="0" width=".3"/>
</header>
</diagram>
</field>
<field id="MFF_IP_DSCP_SHIFTED" title="IPv4/v6 DSCP (Bits 0-5)">
<p>
This field is the TOS byte shifted right to put the DSCP bits in the
6 least-significant bits:
</p>
<diagram>
<header name="OXM_OF_IP_DSCP">
<bits name="zero" above="2" below="0" width=".3"/>
<bits name="DSCP" above="6" width=".9"/>
</header>
</diagram>
</field>
<field id="MFF_IP_ECN" title="IPv4/v6 ECN">
<p>
This field is the TOS byte with the DSCP bits cleared to 0:
</p>
<diagram>
<header name="OXM_OF_IP_ECN">
<bits name="zero" above="6" below="0" width=".9"/>
<bits name="ECN" above="2" width=".35"/>
</header>
</diagram>
</field>
</group>
<group title="Layer 3: ARP">
<p>
In theory, Address Resolution Protocol, or ARP, is a generic protocol
generic protocol that can be used to obtain the hardware address that
corresponds to any higher-level protocol address. In contemporary usage,
ARP is used only in Ethernet networks to obtain the Ethernet address for
a given IPv4 address. OpenFlow and Open vSwitch only support this usage
of ARP. For this use case, an ARP packet has the following format, with
the ARP fields exposed as Open vSwitch fields highlighted:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x806" width="0.4"/>
</header>
<header name="ARP">
<bits name="hrd" above="16" below="1" width=".3"/>
<bits name="pro" above="16" below="0x800" width=".3"/>
<bits name="hln" above="8" below="6" width=".2"/>
<bits name="pln" above="8" below="4" width=".2"/>
<bits name="op" above="16" width=".2" fill="yes"/>
<bits name="sha" above="48" width="0.5" fill="yes"/>
<bits name="spa" above="16" width="0.3" fill="yes"/>
<bits name="tha" above="48" width="0.5" fill="yes"/>
<bits name="tpa" above="16" width="0.3" fill="yes"/>
</header>
</diagram>
<p>
The ARP fields are also used for RARP, the Reverse Address Resolution
Protocol, which shares ARP's wire format.
</p>
<field id="MFF_ARP_OP" title="ARP Opcode">
Even though this is a 16-bit field, Open vSwitch does not support ARP
opcodes greater than 255; it treats them to zero. This works adequately
because in practice ARP and RARP only use opcodes 1 through 4.
</field>
<field id="MFF_ARP_SPA" title="ARP Source IPv4 Address"/>
<field id="MFF_ARP_TPA" title="ARP Target IPv4 Address"/>
<field id="MFF_ARP_SHA" title="ARP Source Ethernet Address"/>
<field id="MFF_ARP_THA" title="ARP Target Ethernet Address"/>
</group>
<group title="Layer 4: TCP, UDP, and SCTP">
<p>
For matching purposes, no distinction is made whether these protocols are
encapsulated within IPv4 or IPv6.
</p>
<h2>TCP</h2>
<p>
The following diagram shows TCP within IPv4. Open vSwitch also supports
TCP in IPv6. Only TCP fields implemented as Open vSwitch fields are
shown:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" below="6" width="0.3"/>
<bits name="src" above="32" width="0.4"/>
<bits name="dst" above="32" width="0.4"/>
</header>
<header name="TCP">
<bits name="src" above="16" width=".2"/>
<bits name="dst" above="16" width=".2"/>
<bits name="..." width=".75"/>
<bits name="flags" above="12" width=".3"/>
<bits name="..." width=".6"/>
</header>
<dots/>
</diagram>
<field id="MFF_TCP_SRC" title="TCP Source Port">
Open vSwitch 1.6 added support for bitwise matching.
</field>
<field id="MFF_TCP_DST" title="TCP Destination Port">
Open vSwitch 1.6 added support for bitwise matching.
</field>
<field id="MFF_TCP_FLAGS" title="TCP Flags">
<p>
This field holds the TCP flags. TCP currently defines 9 flag bits. An
additional 3 bits are reserved. For more information, see [RFC 793],
[RFC 3168], and [RFC 3540].
</p>
<p>
Matches on this field are most conveniently written in terms of
symbolic names (given in the diagram below), each preceded by either
<code>+</code> for a flag that must be set, or <code>-</code> for a
flag that must be unset, without any other delimiters between the
flags. Flags not mentioned are wildcarded. For example,
<code>tcp,tcp_flags=+syn-ack</code> matches TCP SYNs that are not ACKs,
and <code>tcp,tcp_flags=+[200]</code> matches TCP packets with the
reserved [200] flag set. Matches can also be written as
<code><var>flags</var>/<var>mask</var></code>, where <var>flags</var>
and <var>mask</var> are 16-bit numbers in decimal or in hexadecimal
prefixed by <code>0x</code>.
</p>
<p>
The flag bits are:
</p>
<diagram>
<header>
<bits name="zero" above="4" below="0" width=".9"/>
</header>
<nospace/>
<header name="reserved">
<bits name="[800]" above="1" width=".35"/>
<bits name="[400]" above="1" width=".35"/>
<bits name="[200]" above="1" width=".35"/>
</header>
<nospace/>
<header name="later RFCs">
<bits name="NS" above="1" width=".35"/>
<bits name="CWR" above="1" width=".35"/>
<bits name="ECE" above="1" width=".35"/>
</header>
<nospace/>
<header name="RFC 793">
<bits name="URG" above="1" width=".35"/>
<bits name="ACK" above="1" width=".35"/>
<bits name="PSH" above="1" width=".35"/>
<bits name="RST" above="1" width=".35"/>
<bits name="SYN" above="1" width=".35"/>
<bits name="FIN" above="1" width=".35"/>
</header>
</diagram>
</field>
<h2>UDP</h2>
<p>
The following diagram shows UDP within IPv4. Open vSwitch also supports
UDP in IPv6. Only UDP fields that Open vSwitch exposes as fields are
shown:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" below="17" width="0.3"/>
<bits name="src" above="32" width="0.4"/>
<bits name="dst" above="32" width="0.4"/>
</header>
<header name="UDP">
<bits name="src" above="16" width=".2"/>
<bits name="dst" above="16" width=".2"/>
<bits name="..." width=".4"/>
</header>
<dots/>
</diagram>
<field id="MFF_UDP_SRC" title="UDP Source Port"/>
<field id="MFF_UDP_DST" title="UDP Destination Port"/>
<h2>SCTP</h2>
<p>
The following diagram shows SCTP within IPv4. Open vSwitch also supports
SCTP in IPv6. Only SCTP fields that Open vSwitch exposes as fields are
shown:
</p>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" below="132" width="0.3"/>
<bits name="src" above="32" width="0.4"/>
<bits name="dst" above="32" width="0.4"/>
</header>
<header name="SCTP">
<bits name="src" above="16" width=".2"/>
<bits name="dst" above="16" width=".2"/>
<bits name="..." width=".8"/>
</header>
<dots/>
</diagram>
<field id="MFF_SCTP_SRC" title="SCTP Source Port"/>
<field id="MFF_SCTP_DST" title="SCTP Destination Port"/>
</group>
<group title="Layer 4: ICMPv4 and ICMPv6">
<h2>ICMPv4</h2>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x800" width="0.4"/>
</header>
<header name="IPv4">
<bits name="..." width="0.4"/>
<bits name="proto" above="8" below="1" width="0.3"/>
<bits name="src" above="32" width="0.4"/>
<bits name="dst" above="32" width="0.4"/>
</header>
<header name="ICMPv4">
<bits name="type" above="8" width=".3"/>
<bits name="code" above="8" width=".3"/>
<bits name="..." width=".8"/>
</header>
<dots/>
</diagram>
<field id="MFF_ICMPV4_TYPE" title="ICMPv4 Type">
<p>
For historical reasons, in an ICMPv4 flow, Open vSwitch interprets
matches on <code>tp_src</code> as actually referring to the ICMP type.
</p>
</field>
<field id="MFF_ICMPV4_CODE" title="ICMPv4 Code">
<p>
For historical reasons, in an ICMPv4 flow, Open vSwitch interprets
matches on <code>tp_dst</code> as actually referring to the ICMP code.
</p>
</field>
<h2>ICMPv6</h2>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x86dd" width="0.4"/>
</header>
<header name="IPv6">
<bits name="..." width="0.2"/>
<bits name="next" above="8" below="58" width="0.3"/>
<bits name="src" above="128" width="0.4"/>
<bits name="dst" above="128" width="0.4"/>
</header>
<header name="ICMPv6">
<bits name="type" above="8" width=".3"/>
<bits name="code" above="8" width=".3"/>
<bits name="..." width=".8"/>
</header>
<dots/>
</diagram>
<field id="MFF_ICMPV6_TYPE" title="ICMPv6 Type"/>
<field id="MFF_ICMPV6_CODE" title="ICMPv6 Code"/>
<h2>ICMPv6 Neighbor Discovery</h2>
<diagram>
<header name="Ethernet">
<bits name="dst" above="48" width="0.4"/>
<bits name="src" above="48" width="0.4"/>
<bits name="type" above="16" below="0x86dd" width="0.4"/>
</header>
<header name="IPv6">
<bits name="..." width="0.2"/>
<bits name="next" above="8" below="58" width="0.3"/>
<bits name="src" above="128" width="0.4"/>
<bits name="dst" above="128" width="0.4"/>
</header>
<header name="ICMPv6">
<bits name="type" above="8" below="135/136" width=".3"/>
<bits name="code" above="8" below="0" width=".3"/>
<bits name="..." width=".8"/>
</header>
<header name="ICMPv6 ND">
<bits name="target" above="128" width=".4"/>
<bits name="option ..." width=".6"/>
</header>
</diagram>
<field id="MFF_ND_TARGET" title="ICMPv6 Neighbor Discovery Target IPv6"/>
<field id="MFF_ND_SLL"
title="ICMPv6 Neighbor Discovery Source Ethernet Address"/>
<field id="MFF_ND_TLL"
title="ICMPv6 Neighbor Discovery Target Ethernet Address"/>
</group>
<h1>References</h1>
<dl>
<dt>Casado</dt>
<dd>
M. Casado, M. J. Freedman, J. Pettit, J. Luo, N. McKeown, and
S. Shenker, ``Ethane: Taking Control of the Enterprise,''
Computer Communications Review, October 2007.
</dd>
<dt>EXT-56</dt>
<dd>
J. Tonsing, ``Permit one of a set of prerequisites to apply, e.g. don't
preclude non-Ethernet media,'' <url
href="https://rs.opennetworking.org/bugs/browse/EXT-56"/> (ONF
members only).
</dd>
<dt>EXT-112</dt>
<dd>
J. Tourrilhes, ``Support non-Ethernet packets throughout the
pipeline,'' <url
href="https://rs.opennetworking.org/bugs/browse/EXT-112"/> (ONF
members only).
</dd>
<dt>EXT-134</dt>
<dd>
J. Tourrilhes, ``Match first nibble of the MPLS payload,'' <url
href="https://rs.opennetworking.org/bugs/browse/EXT-134"/> (ONF
members only).
</dd>
<dt>Geneve</dt>
<dd>
J. Gross, I. Ganga, and T. Sridhar, editors, ``Geneve: Generic Network
Virtualization Encapsulation,'' <url
href="https://datatracker.ietf.org/doc/draft-ietf-nvo3-geneve/"/>.
</dd>
<dt>IEEE OUI</dt>
<dd>
IEEE Standards Association, ``MAC Address Block Large (MA-L),''
<url
href="https://standards.ieee.org/develop/regauth/oui/index.html"/>.
</dd>
<dt>NSH</dt>
<dd>
P. Quinn and U. Elzur, editors, ``Network Service Header,'' <url
href="https://datatracker.ietf.org/doc/draft-ietf-sfc-nsh/"/>.
</dd>
<dt>OpenFlow 1.0.1</dt>
<dd>
Open Networking Foundation, ``OpenFlow Switch Errata, Version
1.0.1,'' June 2012.
</dd>
<dt>OpenFlow 1.1</dt>
<dd>
OpenFlow Consortium, ``OpenFlow Switch Specification Version
1.1.0 Implemented (Wire Protocol 0x02),'' February 2011.
</dd>
<dt>OpenFlow 1.5</dt>
<dd>
Open Networking Foundation, ``OpenFlow Switch Specification Version
1.5.0 (Protocol version 0x06),'' December 2014.
</dd>
<dt>OpenFlow Extensions 1.3.x Package 2</dt>
<dd>
Open Networking Foundation, ``OpenFlow Extensions 1.3.x Package 2,''
December 2013.
</dd>
<dt>TCP Flags Match Field Extension</dt>
<dd>
Open Networking Foundation, ``TCP flags match field Extension,'' December
2014. In [OpenFlow Extensions 1.3.x Package 2].
</dd>
<dt>Pepelnjak</dt>
<dd>
I. Pepelnjak, ``OpenFlow and Fermi Estimates,'' <url
href="http://blog.ipspace.net/2013/09/openflow-and-fermi-estimates.html"/>.
</dd>
<dt>RFC 793</dt>
<dd>
``Transmission Control Protocol,'' <url
href="http://www.ietf.org/rfc/rfc793.txt"/>.
</dd>
<dt>RFC 3032</dt>
<dd>
E. Rosen, D. Tappan, G. Fedorkow, Y. Rekhter, D. Farinacci,
T. Li, and A. Conta, ``MPLS Label Stack Encoding,'' <url
href="http://www.ietf.org/rfc/rfc3032.txt"/>.
</dd>
<dt>RFC 3168</dt>
<dd>
K. Ramakrishnan, S. Floyd, and D. Black, ``The Addition of Explicit
Congestion Notification (ECN) to IP,'' <url href="https://tools.ietf.org/html/rfc3168"/>.
</dd>
<dt>RFC 3540</dt>
<dd>
N. Spring, D. Wetherall, and D. Ely, ``Robust Explicit Congestion
Notification (ECN) Signaling with Nonces,'' <url
href="https://tools.ietf.org/html/rfc3540"/>.
</dd>
<dt>RFC 4632</dt>
<dd>
V. Fuller and T. Li, ``Classless Inter-domain Routing (CIDR): The
Internet Address Assignment and Aggregation Plan,'' <url
href="https://tools.ietf.org/html/rfc4632"/>.
</dd>
<dt>RFC 5462</dt>
<dd>
L. Andersson and R. Asati, ``Multiprotocol Label Switching
(MPLS) Label Stack Entry: ``EXP'' Field Renamed to ``Traffic
Class'' Field,'' <url
href="http://www.ietf.org/rfc/rfc5462.txt"/>.
</dd>
<dt>RFC 6830</dt>
<dd>
D. Farinacci, V. Fuller, D. Meyer, and D. Lewis, ``The
Locator/ID Separation Protocol (LISP),'' <url
href="http://www.ietf.org/rfc/rfc6830.txt"/>.
</dd>
<dt>RFC 7348</dt>
<dd>
M. Mahalingam, D. Dutt, K. Duda, P. Agarwal, L. Kreeger, T. Sridhar,
M. Bursell, and C. Wright, ``Virtual eXtensible Local Area Network
(VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over
Layer 3 Networks, '' <url href="https://tools.ietf.org/html/rfc7348"/>.
</dd>
<dt>Srinivasan</dt>
<dd>
V. Srinivasan, S. Suriy, and G. Varghese, ``Packet
Classification using Tuple Space Search,'' SIGCOMM 1999.
</dd>
<dt>Pagiamtzis</dt>
<dd>
K. Pagiamtzis and A. Sheikholeslami, ``Content-addressable
memory (CAM) circuits and architectures: A tutorial and
survey,'' IEEE Journal of Solid-State Circuits, vol. 41, no. 3,
pp. 712-727, March 2006.
</dd>
<dt>VXLAN Group Policy Option</dt>
<dd>
M. Smith and L. Kreeger, `` VXLAN Group Policy Option.'' Internet-Draft.
<url href="https://tools.ietf.org/html/draft-smith-vxlan-group-policy"/>.
</dd>
</dl>
<h1>Authors</h1>
<p>
Ben Pfaff, with advice from Justin Pettit and Jean Tourrilhes.
</p>
</fields>
<!--
OXM fields not yet supported Future Directions References/See Also
OXM fields required by various versions and by the "Conformance Test Specification for OpenFlow Switch Specification 1.0.1"
-->
|