* FOR A PARTICULAR PURPOSE.
*
* Reference documentation:
- * http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080094c52.shtml
- * http://www.cisco.com/warp/public/473/21.html
- * http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
+ * http://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html
+ * http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
*
*/
#define VTP_DOMAIN_NAME_LEN 32
#define VTP_MD5_DIGEST_LEN 16
#define VTP_UPDATE_TIMESTAMP_LEN 12
-#define VTP_VLAN_INFO_OFFSET 12
+#define VTP_VLAN_INFO_FIXED_PART_LEN 12 /* length of VLAN info before VLAN name */
#define VTP_SUMMARY_ADV 0x01
#define VTP_SUBSET_ADV 0x02
ND_TCHECK2(*tptr, len);
vtp_vlan = (const struct vtp_vlan_*)tptr;
+ if (len < VTP_VLAN_INFO_FIXED_PART_LEN)
+ goto trunc;
ND_TCHECK(*vtp_vlan);
ND_PRINT((ndo, "\n\tVLAN info status %s, type %s, VLAN-id %u, MTU %u, SAID 0x%08x, Name ",
tok2str(vtp_vlan_status,"Unknown",vtp_vlan->status),
EXTRACT_16BITS(&vtp_vlan->vlanid),
EXTRACT_16BITS(&vtp_vlan->mtu),
EXTRACT_32BITS(&vtp_vlan->index)));
- fn_printzp(ndo, tptr + VTP_VLAN_INFO_OFFSET, vtp_vlan->name_len, NULL);
-
- /*
- * Vlan names are aligned to 32-bit boundaries.
- */
- len -= VTP_VLAN_INFO_OFFSET + 4*((vtp_vlan->name_len + 3)/4);
- tptr += VTP_VLAN_INFO_OFFSET + 4*((vtp_vlan->name_len + 3)/4);
+ len -= VTP_VLAN_INFO_FIXED_PART_LEN;
+ tptr += VTP_VLAN_INFO_FIXED_PART_LEN;
+ if (len < 4*((vtp_vlan->name_len + 3)/4))
+ goto trunc;
+ ND_TCHECK2(*tptr, vtp_vlan->name_len);
+ fn_printzp(ndo, tptr, vtp_vlan->name_len, NULL);
+
+ /*
+ * Vlan names are aligned to 32-bit boundaries.
+ */
+ len -= 4*((vtp_vlan->name_len + 3)/4);
+ tptr += 4*((vtp_vlan->name_len + 3)/4);
/* TLV information follows */
while (len > 0) {
/*
- * Cisco specs says 2 bytes for type + 2 bytes for length, take only 1
- * See: http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
+ * Cisco specs say 2 bytes for type + 2 bytes for length;
+ * see http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
+ * However, actual packets on the wire appear to use 1
+ * byte for the type and 1 byte for the length, so that's
+ * what we do.
*/
+ if (len < 2)
+ goto trunc;
+ ND_TCHECK2(*tptr, 2);
type = *tptr;
tlv_len = *(tptr+1);
tok2str(vtp_vlan_tlv_values, "Unknown", type),
type));
- /*
- * infinite loop check
- */
- if (type == 0 || tlv_len == 0) {
+ if (len < tlv_len * 2 + 2) {
+ ND_PRINT((ndo, " (TLV goes past the end of the packet)"));
return;
}
-
ND_TCHECK2(*tptr, tlv_len * 2 +2);
- tlv_value = EXTRACT_16BITS(tptr+2);
-
- switch (type) {
- case VTP_VLAN_STE_HOP_COUNT:
- ND_PRINT((ndo, ", %u", tlv_value));
- break;
-
- case VTP_VLAN_PRUNING:
- ND_PRINT((ndo, ", %s (%u)",
- tlv_value == 1 ? "Enabled" : "Disabled",
- tlv_value));
- break;
-
- case VTP_VLAN_STP_TYPE:
- ND_PRINT((ndo, ", %s (%u)",
- tok2str(vtp_stp_type_values, "Unknown", tlv_value),
- tlv_value));
- break;
-
- case VTP_VLAN_BRIDGE_TYPE:
- ND_PRINT((ndo, ", %s (%u)",
- tlv_value == 1 ? "SRB" : "SRT",
- tlv_value));
- break;
-
- case VTP_VLAN_BACKUP_CRF_MODE:
- ND_PRINT((ndo, ", %s (%u)",
- tlv_value == 1 ? "Backup" : "Not backup",
- tlv_value));
- break;
-
- /*
- * FIXME those are the defined TLVs that lack a decoder
- * you are welcome to contribute code ;-)
- */
-
- case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER:
- case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER:
- case VTP_VLAN_PARENT_VLAN:
- case VTP_VLAN_TRANS_BRIDGED_VLAN:
- case VTP_VLAN_ARP_HOP_COUNT:
- default:
- print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2);
- break;
+ /*
+ * We assume the value is a 2-byte integer; the length is
+ * in units of 16-bit words.
+ */
+ if (tlv_len != 1) {
+ ND_PRINT((ndo, " (invalid TLV length %u != 1)", tlv_len));
+ return;
+ } else {
+ tlv_value = EXTRACT_16BITS(tptr+2);
+
+ switch (type) {
+ case VTP_VLAN_STE_HOP_COUNT:
+ ND_PRINT((ndo, ", %u", tlv_value));
+ break;
+
+ case VTP_VLAN_PRUNING:
+ ND_PRINT((ndo, ", %s (%u)",
+ tlv_value == 1 ? "Enabled" : "Disabled",
+ tlv_value));
+ break;
+
+ case VTP_VLAN_STP_TYPE:
+ ND_PRINT((ndo, ", %s (%u)",
+ tok2str(vtp_stp_type_values, "Unknown", tlv_value),
+ tlv_value));
+ break;
+
+ case VTP_VLAN_BRIDGE_TYPE:
+ ND_PRINT((ndo, ", %s (%u)",
+ tlv_value == 1 ? "SRB" : "SRT",
+ tlv_value));
+ break;
+
+ case VTP_VLAN_BACKUP_CRF_MODE:
+ ND_PRINT((ndo, ", %s (%u)",
+ tlv_value == 1 ? "Backup" : "Not backup",
+ tlv_value));
+ break;
+
+ /*
+ * FIXME those are the defined TLVs that lack a decoder
+ * you are welcome to contribute code ;-)
+ */
+
+ case VTP_VLAN_SOURCE_ROUTING_RING_NUMBER:
+ case VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER:
+ case VTP_VLAN_PARENT_VLAN:
+ case VTP_VLAN_TRANS_BRIDGED_VLAN:
+ case VTP_VLAN_ARP_HOP_COUNT:
+ default:
+ print_unknown_data(ndo, tptr, "\n\t\t ", 2 + tlv_len*2);
+ break;
+ }
}
len -= 2 + tlv_len*2;
tptr += 2 + tlv_len*2;
projects / tcpdump / blobdiff