udld: initial support

Summary of changes:
- Complete UDLD protocol support was added according to RFC5171
- UDLD checksum implementation was added
- UDLD unit tests were added
- CI has been updated to run UDLD unit tests

That's how sample/udld looks in tcpdump:
tcpdump: listening on lo0, link-type EN10MB (Ethernet), capture size 262144 bytes
06:23:33.536964 UDLDv1, Code Probe message (1), Flags [RT, RSY] (0x03), length 60
        Checksum 0x6d85 (unverified)
        Device-ID TLV (0x0001) TLV, length 15, FOC1031Z7JG
        Port-ID TLV (0x0002) TLV, length 9, Gi0/1
        Echo TLV (0x0003) TLV, length 8, ^@^@^@^@
        Message Interval TLV (0x0004) TLV, length 5, 7s
        Timeout Interval TLV (0x0005) TLV, length 5, 5s
        Device Name TLV (0x0006) TLV, length 6, S1
        Sequence Number TLV (0x0007) TLV, length 8, 1
        0x0000:  2103 6d85 0001 000f 464f 4331 3033 315a  !.m.....FOC1031Z
        0x0010:  374a 4700 0200 0947 6930 2f31 0003 0008  7JG....Gi0/1....
        0x0020:  0000 0000 0004 0005 0700 0500 0505 0006  ................
        0x0030:  0006 5331 0007 0008 0000 0001            ..S1........

Signed-off-by: Valery Ivanov <ivalery111@gmail.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/include/libnet/libnet-headers.h b/include/libnet/libnet-headers.h
index afbb5c3..01194c9 100644
--- a/include/libnet/libnet-headers.h
+++ b/include/libnet/libnet-headers.h
@@ -107,6 +107,7 @@
 #define LIBNET_SEBEK_H          0x30    /* sebek header:          48 bytes */   
 #define LIBNET_STP_CONF_H       0x23    /**< STP conf header:     35 bytes */
 #define LIBNET_STP_TCN_H        0x04    /**< STP tcn header:       4 bytes */
+#define LIBNET_UDLD_H           0x04    /**< UDLD header:          4 bytes */
 #define LIBNET_TOKEN_RING_H     0x16    /**< Token Ring header:   22 bytes */
 #define LIBNET_TCP_H            0x14    /**< TCP header:          20 bytes */
 #define LIBNET_UDP_H            0x08    /**< UDP header:           8 bytes */
@@ -1734,6 +1735,64 @@ struct libnet_stp_tcn_hdr
     uint8_t stp_bpdu_type;   /* bridge protocol data unit type */
 };
 
+/*
+ * UDLD header
+ * UniDirectional Link Detection
+ * Base header size: 4 bytes
+*/
+struct libnet_udld_hdr
+{
+    /* LLC Info */
+#define LIBNET_UDLD_DEST_MAC {0x01, 0x00, 0x0C, 0xCC, 0xCC, 0xCC}
+
+    /* UDLD SNAP Format */
+#define LIBNET_UDLD_LLC_DSAP        0xAA
+#define LIBNET_UDLD_LLC_SSAP        0xAA
+#define LIBNET_UDLD_LLC_CONTROL     0x03
+#define LIBNET_UDLD_OID             {0x00, 0x00, 0x0C}
+#define LIBNET_UDLD_HDLC_PROTO_TYPE 0x0111
+
+    /* Protocol Data Unit (PDU) Format */
+    uint8_t version_opcode;
+#define LIBNET_UDLD_PDU_VERSION                0x01
+#define LIBNET_UDLD_PDU_VERSION_OFFSET         (5)
+
+#define LIBNET_UDLD_PDU_OPCODE_RESERVED        0x00 /* Reserved opcode message           */
+#define LIBNET_UDLD_PDU_OPCODE_PROBE           0x01 /* Probe opcode message              */
+#define LIBNET_UDLD_PDU_OPCODE_ECHO            0x02 /* Echo opcode message               */
+#define LIBNET_UDLD_PDU_OPCODE_FLUSH           0x03 /* Flush opcode message              */
+#define LIBNET_UDLD_PDU_OPCODE_RESERVED_FUTURE 0x04 /* Reserved for future use 0x04-0x1F */
+#define LIBNET_UDLD_PDU_OPCODE_MASK            0x1F
+
+    uint8_t flags;
+#define LIBNET_UDLD_FLAG_RT       0x01 /* Bit 0  : Recommended timeout flag (RT) */
+#define LIBNET_UDLD_FLAG_RSY      0x02 /* Bit 1  : ReSynch flag (RSY)            */
+#define LIBNET_UDLD_FLAG_RESERVED 0x03 /* Bit 2-7: Reserved for future use       */
+
+    uint16_t checksum; /* IP-like checksum */
+#define LIBNET_PROTO_UDLD    202
+
+    /* TLVs */
+#define LIBNET_UDLD_TLV_HDR_SIZE               0x04 /* UDLD TLV's header size 4 bytes */
+
+    uint16_t tlv__type;
+#define LIBNET_UDLD_DEVICE_ID        0x0001   /* Value format: ASCII character string           */
+#define LIBNET_UDLD_PORT_ID          0x0002   /* Value format: ASCII character string           */
+#define LIBNET_UDLD_ECHO             0x0003   /* Value format: List of ID pairs                 */
+#define LIBNET_UDLD_MESSAGE_INTERVAL 0x0004   /* Value format: 8-bit unsigned integer           */
+#define LIBNET_UDLD_TIMEOUT_INTERVAL 0x0005   /* Value format: 8-bit unsigned integer           */
+#define LIBNET_UDLD_DEVICE_NAME      0x0006   /* Value format: ASCII character string           */
+#define LIBNET_UDLD_SEQUENCE_NUMBER  0x0007   /* Value format: 32-bit unsigned integer          */
+/* Reserved TLVs                     >0x0007     Value format: To be skipped by parsing routine */
+
+    uint16_t tlv__length;
+
+    /* TLV value types */
+#define LIBNET_UDLD_VALUE_TYPE_ASCII       (0)
+#define LIBNET_UDLD_VALUE_TYPE_ID_PAIRS    (1)
+#define LIBNET_UDLD_VALUE_TYPE_8_BIT_UINT  (2)
+#define LIBNET_UDLD_VALUE_TYPE_32_BIT_UINT (3)
+};
 
 /*
  *  TCP header