sFlow: Modernize packet parsing style.

Enable ND_LONGJMP_FROM_TCHECK. Remove many redundant ND_TCHECK*()
instances. Report invalid packets as invalid, not truncated. Test
whether the invalid packet is entirely in the buffer.  Fix a typo in a
comment. Use a variable where it was intended.

1 files changed, 12 insertions, 67 deletions

diff --git a/print-sflow.c b/print-sflow.c
index ba79e6a6..51325e28 100644
--- a/print-sflow.c
+++ b/print-sflow.c
@@ -27,6 +27,7 @@
 
 #include "netdissect-stdinc.h"
 
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 #include "extract.h"
 #include "addrtoname.h"
@@ -308,7 +309,6 @@ print_sflow_counter_generic(netdissect_options *ndo,
 	return 1;
 
     sflow_gen_counter = (const struct sflow_generic_counter_t *)pointer;
-    ND_TCHECK_SIZE(sflow_gen_counter);
     ND_PRINT("\n\t      ifindex %u, iftype %u, ifspeed %" PRIu64 ", ifdirection %u (%s)",
 	   GET_BE_U_4(sflow_gen_counter->ifindex),
 	   GET_BE_U_4(sflow_gen_counter->iftype),
@@ -342,9 +342,6 @@ print_sflow_counter_generic(netdissect_options *ndo,
 	   GET_BE_U_4(sflow_gen_counter->ifpromiscmode));
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -357,7 +354,6 @@ print_sflow_counter_ethernet(netdissect_options *ndo,
 	return 1;
 
     sflow_eth_counter = (const struct sflow_ethernet_counter_t *)pointer;
-    ND_TCHECK_SIZE(sflow_eth_counter);
     ND_PRINT("\n\t      align errors %u, fcs errors %u, single collision %u, multiple collision %u, test error %u",
 	   GET_BE_U_4(sflow_eth_counter->alignerrors),
 	   GET_BE_U_4(sflow_eth_counter->fcserrors),
@@ -376,9 +372,6 @@ print_sflow_counter_ethernet(netdissect_options *ndo,
 	   GET_BE_U_4(sflow_eth_counter->symbol_errors));
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -398,7 +391,6 @@ print_sflow_counter_basevg(netdissect_options *ndo,
 	return 1;
 
     sflow_100basevg_counter = (const struct sflow_100basevg_counter_t *)pointer;
-    ND_TCHECK_SIZE(sflow_100basevg_counter);
     ND_PRINT("\n\t      in high prio frames %u, in high prio octets %" PRIu64,
 	   GET_BE_U_4(sflow_100basevg_counter->in_highpriority_frames),
 	   GET_BE_U_8(sflow_100basevg_counter->in_highpriority_octets));
@@ -423,9 +415,6 @@ print_sflow_counter_basevg(netdissect_options *ndo,
 	   GET_BE_U_8(sflow_100basevg_counter->hc_out_highpriority_octets));
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -438,7 +427,6 @@ print_sflow_counter_vlan(netdissect_options *ndo,
 	return 1;
 
     sflow_vlan_counter = (const struct sflow_vlan_counter_t *)pointer;
-    ND_TCHECK_SIZE(sflow_vlan_counter);
     ND_PRINT("\n\t      vlan_id %u, octets %" PRIu64
 	   ", unicast_pkt %u, multicast_pkt %u, broadcast_pkt %u, discards %u",
 	   GET_BE_U_4(sflow_vlan_counter->vlan_id),
@@ -449,9 +437,6 @@ print_sflow_counter_vlan(netdissect_options *ndo,
 	   GET_BE_U_4(sflow_vlan_counter->discards));
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 struct sflow_processor_counter_t {
@@ -472,7 +457,6 @@ print_sflow_counter_processor(netdissect_options *ndo,
 	return 1;
 
     sflow_processor_counter = (const struct sflow_processor_counter_t *)pointer;
-    ND_TCHECK_SIZE(sflow_processor_counter);
     ND_PRINT("\n\t      5sec %u, 1min %u, 5min %u, total_mem %" PRIu64
 	   ", total_mem %" PRIu64,
 	   GET_BE_U_4(sflow_processor_counter->five_sec_util),
@@ -482,9 +466,6 @@ print_sflow_counter_processor(netdissect_options *ndo,
 	   GET_BE_U_8(sflow_processor_counter->free_memory));
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -508,7 +489,6 @@ sflow_print_counter_records(netdissect_options *ndo,
 	if (tlen < sizeof(struct sflow_counter_record_t))
 	    return 1;
 	sflow_counter_record = (const struct sflow_counter_record_t *)tptr;
-	ND_TCHECK_SIZE(sflow_counter_record);
 
 	enterprise = GET_BE_U_4(sflow_counter_record->format);
 	counter_type = enterprise & 0x0FFF;
@@ -564,9 +544,6 @@ sflow_print_counter_records(netdissect_options *ndo,
     }
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -580,7 +557,6 @@ sflow_print_counter_sample(netdissect_options *ndo,
 	return 1;
 
     sflow_counter_sample = (const struct sflow_counter_sample_t *)pointer;
-    ND_TCHECK_SIZE(sflow_counter_sample);
 
     nrecords   = GET_BE_U_4(sflow_counter_sample->records);
 
@@ -593,9 +569,6 @@ sflow_print_counter_sample(netdissect_options *ndo,
     return sflow_print_counter_records(ndo, pointer + sizeof(struct sflow_counter_sample_t),
 				       len - sizeof(struct sflow_counter_sample_t),
 				       nrecords);
-
-trunc:
-    return 1;
 }
 
 static int
@@ -610,7 +583,6 @@ sflow_print_expanded_counter_sample(netdissect_options *ndo,
 	return 1;
 
     sflow_expanded_counter_sample = (const struct sflow_expanded_counter_sample_t *)pointer;
-    ND_TCHECK_SIZE(sflow_expanded_counter_sample);
 
     nrecords = GET_BE_U_4(sflow_expanded_counter_sample->records);
 
@@ -623,9 +595,6 @@ sflow_print_expanded_counter_sample(netdissect_options *ndo,
     return sflow_print_counter_records(ndo, pointer + sizeof(struct sflow_expanded_counter_sample_t),
 				       len - sizeof(struct sflow_expanded_counter_sample_t),
 				       nrecords);
-
-trunc:
-    return 1;
 }
 
 static int
@@ -638,7 +607,6 @@ print_sflow_raw_packet(netdissect_options *ndo,
 	return 1;
 
     sflow_flow_raw = (const struct sflow_expanded_flow_raw_t *)pointer;
-    ND_TCHECK_SIZE(sflow_flow_raw);
     ND_PRINT("\n\t      protocol %s (%u), length %u, stripped bytes %u, header_size %u",
 	   tok2str(sflow_flow_raw_protocol_values,"Unknown",GET_BE_U_4(sflow_flow_raw->protocol)),
 	   GET_BE_U_4(sflow_flow_raw->protocol),
@@ -647,12 +615,9 @@ print_sflow_raw_packet(netdissect_options *ndo,
 	   GET_BE_U_4(sflow_flow_raw->header_size));
 
     /* QUESTION - should we attempt to print the raw header itself?
-       assuming of course there is wnough data present to do so... */
+       assuming of course there is enough data present to do so... */
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -665,16 +630,12 @@ print_sflow_ethernet_frame(netdissect_options *ndo,
 	return 1;
 
     sflow_ethernet_frame = (const struct sflow_ethernet_frame_t *)pointer;
-    ND_TCHECK_SIZE(sflow_ethernet_frame);
 
     ND_PRINT("\n\t      frame len %u, type %u",
 	   GET_BE_U_4(sflow_ethernet_frame->length),
 	   GET_BE_U_4(sflow_ethernet_frame->type));
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -687,7 +648,6 @@ print_sflow_extended_switch_data(netdissect_options *ndo,
 	return 1;
 
     sflow_extended_sw_data = (const struct sflow_extended_switch_data_t *)pointer;
-    ND_TCHECK_SIZE(sflow_extended_sw_data);
     ND_PRINT("\n\t      src vlan %u, src pri %u, dst vlan %u, dst pri %u",
 	   GET_BE_U_4(sflow_extended_sw_data->src_vlan),
 	   GET_BE_U_4(sflow_extended_sw_data->src_pri),
@@ -695,9 +655,6 @@ print_sflow_extended_switch_data(netdissect_options *ndo,
 	   GET_BE_U_4(sflow_extended_sw_data->dst_pri));
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -722,7 +679,6 @@ sflow_print_flow_records(netdissect_options *ndo,
 	    return 1;
 
 	sflow_flow_record = (const struct sflow_flow_record_t *)tptr;
-	ND_TCHECK_SIZE(sflow_flow_record);
 
 	/* so, the funky encoding means we cannot blythly mask-off
 	   bits, we must also check the enterprise. */
@@ -785,9 +741,6 @@ sflow_print_flow_records(netdissect_options *ndo,
     }
 
     return 0;
-
-trunc:
-    return 1;
 }
 
 static int
@@ -801,7 +754,6 @@ sflow_print_flow_sample(netdissect_options *ndo,
 	return 1;
 
     sflow_flow_sample = (const struct sflow_flow_sample_t *)pointer;
-    ND_TCHECK_SIZE(sflow_flow_sample);
 
     nrecords = GET_BE_U_4(sflow_flow_sample->records);
 
@@ -819,9 +771,6 @@ sflow_print_flow_sample(netdissect_options *ndo,
     return sflow_print_flow_records(ndo, pointer + sizeof(struct sflow_flow_sample_t),
 				    len - sizeof(struct sflow_flow_sample_t),
 				    nrecords);
-
-trunc:
-    return 1;
 }
 
 static int
@@ -835,7 +784,6 @@ sflow_print_expanded_flow_sample(netdissect_options *ndo,
 	return 1;
 
     sflow_expanded_flow_sample = (const struct sflow_expanded_flow_sample_t *)pointer;
-    ND_TCHECK_SIZE(sflow_expanded_flow_sample);
 
     nrecords = GET_BE_U_4(sflow_expanded_flow_sample->records);
 
@@ -846,14 +794,11 @@ sflow_print_expanded_flow_sample(netdissect_options *ndo,
 	   GET_BE_U_4(sflow_expanded_flow_sample->rate),
 	   GET_BE_U_4(sflow_expanded_flow_sample->pool),
 	   GET_BE_U_4(sflow_expanded_flow_sample->drops),
-	   GET_BE_U_4(sflow_expanded_flow_sample->records));
+	   nrecords);
 
     return sflow_print_flow_records(ndo, pointer + sizeof(struct sflow_expanded_flow_sample_t),
 				    len - sizeof(struct sflow_expanded_flow_sample_t),
 				    nrecords);
-
-trunc:
-    return 1;
 }
 
 void
@@ -917,13 +862,12 @@ sflow_print(netdissect_options *ndo,
 
     while (nsamples > 0 && tlen > 0) {
         sflow_sample = (const struct sflow_sample_header *)tptr;
-        ND_TCHECK_SIZE(sflow_sample);
 
         sflow_sample_type = (GET_BE_U_4(sflow_sample->format)&0x0FFF);
         sflow_sample_len = GET_BE_U_4(sflow_sample->len);
 
 	if (tlen < sizeof(struct sflow_sample_header))
-	    goto trunc;
+	    goto invalid;
 
         tptr += sizeof(struct sflow_sample_header);
         tlen -= sizeof(struct sflow_sample_header);
@@ -939,7 +883,7 @@ sflow_print(netdissect_options *ndo,
         }
 
 	if (tlen < sflow_sample_len)
-	    goto trunc;
+	    goto invalid;
 
         /* did we capture enough for fully decoding the sample ? */
         ND_TCHECK_LEN(tptr, sflow_sample_len);
@@ -947,22 +891,22 @@ sflow_print(netdissect_options *ndo,
 	switch(sflow_sample_type) {
         case SFLOW_FLOW_SAMPLE:
 	    if (sflow_print_flow_sample(ndo, tptr, tlen))
-		goto trunc;
+		goto invalid;
             break;
 
         case SFLOW_COUNTER_SAMPLE:
 	    if (sflow_print_counter_sample(ndo, tptr,tlen))
-		goto trunc;
+		goto invalid;
             break;
 
         case SFLOW_EXPANDED_FLOW_SAMPLE:
 	    if (sflow_print_expanded_flow_sample(ndo, tptr, tlen))
-		goto trunc;
+		goto invalid;
 	    break;
 
         case SFLOW_EXPANDED_COUNTER_SAMPLE:
 	    if (sflow_print_expanded_counter_sample(ndo, tptr,tlen))
-		goto trunc;
+		goto invalid;
 	    break;
 
         default:
@@ -976,6 +920,7 @@ sflow_print(netdissect_options *ndo,
     }
     return;
 
- trunc:
-    nd_print_trunc(ndo);
+invalid:
+    nd_print_invalid(ndo);
+    ND_TCHECK_LEN(tptr, tlen);
 }