- vc_info_len = *(tptr+2);
- printf(": %s, %scontrol word, group-ID %u, VC-ID %u, VC-info-length: %u",
- tok2str(l2vpn_encaps_values, "Unknown", EXTRACT_16BITS(tptr)&0x7fff),
- EXTRACT_16BITS(tptr)&0x8000 ? "" : "no ",
- EXTRACT_32BITS(tptr+3),
- EXTRACT_32BITS(tptr+7),
- vc_info_len);
+ /*
+ * We assume the type was supposed to be one of the MPLS
+ * Pseudowire Types.
+ */
+ TLV_TCHECK(7);
+ vc_info_len = GET_U_1(tptr + 2);
+
+ /*
+ * According to RFC 4908, the VC info Length field can be zero,
+ * in which case not only are there no interface parameters,
+ * there's no VC ID.
+ */
+ if (vc_info_len == 0) {
+ ND_PRINT(": %s, %scontrol word, group-ID %u, VC-info-length: %u",
+ tok2str(mpls_pw_types_values, "Unknown", GET_BE_U_2(tptr)&0x7fff),
+ GET_BE_U_2(tptr)&0x8000 ? "" : "no ",
+ GET_BE_U_4(tptr + 3),
+ vc_info_len);
+ break;
+ }
+
+ /* Make sure we have the VC ID as well */
+ TLV_TCHECK(11);
+ ND_PRINT(": %s, %scontrol word, group-ID %u, VC-ID %u, VC-info-length: %u",
+ tok2str(mpls_pw_types_values, "Unknown", GET_BE_U_2(tptr)&0x7fff),
+ GET_BE_U_2(tptr)&0x8000 ? "" : "no ",
+ GET_BE_U_4(tptr + 3),
+ GET_BE_U_4(tptr + 7),
+ vc_info_len);
+ if (vc_info_len < 4) {
+ /* minimum 4, for the VC ID */
+ ND_PRINT(" (invalid, < 4");
+ return(tlv_len+4); /* Type & Length fields not included */
+ }
+ vc_info_len -= 4; /* subtract out the VC ID, giving the length of the interface parameters */
+
+ /* Skip past the fixed information and the VC ID */