/* * Copyright (c) 1998-2007 The TCPDUMP project * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code * distributions retain the above copyright notice and this paragraph * in its entirety, and (2) distributions including binary code include * the above copyright notice and this paragraph in its entirety in * the documentation or other materials provided with the distribution. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE. * * Reference documentation: * https://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html * https://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm * * Original code ode by Carles Kishimoto */ /* \summary: Cisco VLAN Trunking Protocol (VTP) printer */ #include #include "netdissect-stdinc.h" #define ND_LONGJMP_FROM_TCHECK #include "netdissect.h" #include "addrtoname.h" #include "extract.h" #define VTP_HEADER_LEN 36 #define VTP_DOMAIN_NAME_LEN 32 #define VTP_MD5_DIGEST_LEN 16 #define VTP_UPDATE_TIMESTAMP_LEN 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 #define VTP_ADV_REQUEST 0x03 #define VTP_JOIN_MESSAGE 0x04 struct vtp_vlan_ { nd_uint8_t len; nd_uint8_t status; nd_uint8_t type; nd_uint8_t name_len; nd_uint16_t vlanid; nd_uint16_t mtu; nd_uint32_t index; }; static const struct tok vtp_message_type_values[] = { { VTP_SUMMARY_ADV, "Summary advertisement"}, { VTP_SUBSET_ADV, "Subset advertisement"}, { VTP_ADV_REQUEST, "Advertisement request"}, { VTP_JOIN_MESSAGE, "Join message"}, { 0, NULL } }; static const struct tok vtp_header_values[] = { { 0x01, "Followers"}, /* On Summary advertisement, 3rd byte is Followers */ { 0x02, "Seq number"}, /* On Subset advertisement, 3rd byte is Sequence number */ { 0x03, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */ { 0x04, "Rsvd"}, /* On Adver. requests 3rd byte is Rsvd */ { 0, NULL } }; static const struct tok vtp_vlan_type_values[] = { { 0x01, "Ethernet"}, { 0x02, "FDDI"}, { 0x03, "TrCRF"}, { 0x04, "FDDI-net"}, { 0x05, "TrBRF"}, { 0, NULL } }; static const struct tok vtp_vlan_status[] = { { 0x00, "Operational"}, { 0x01, "Suspended"}, { 0, NULL } }; #define VTP_VLAN_SOURCE_ROUTING_RING_NUMBER 0x01 #define VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER 0x02 #define VTP_VLAN_STP_TYPE 0x03 #define VTP_VLAN_PARENT_VLAN 0x04 #define VTP_VLAN_TRANS_BRIDGED_VLAN 0x05 #define VTP_VLAN_PRUNING 0x06 #define VTP_VLAN_BRIDGE_TYPE 0x07 #define VTP_VLAN_ARP_HOP_COUNT 0x08 #define VTP_VLAN_STE_HOP_COUNT 0x09 #define VTP_VLAN_BACKUP_CRF_MODE 0x0A static const struct tok vtp_vlan_tlv_values[] = { { VTP_VLAN_SOURCE_ROUTING_RING_NUMBER, "Source-Routing Ring Number TLV"}, { VTP_VLAN_SOURCE_ROUTING_BRIDGE_NUMBER, "Source-Routing Bridge Number TLV"}, { VTP_VLAN_STP_TYPE, "STP type TLV"}, { VTP_VLAN_PARENT_VLAN, "Parent VLAN TLV"}, { VTP_VLAN_TRANS_BRIDGED_VLAN, "Translationally bridged VLANs TLV"}, { VTP_VLAN_PRUNING, "Pruning TLV"}, { VTP_VLAN_BRIDGE_TYPE, "Bridge Type TLV"}, { VTP_VLAN_ARP_HOP_COUNT, "Max ARP Hop Count TLV"}, { VTP_VLAN_STE_HOP_COUNT, "Max STE Hop Count TLV"}, { VTP_VLAN_BACKUP_CRF_MODE, "Backup CRF Mode TLV"}, { 0, NULL } }; static const struct tok vtp_stp_type_values[] = { { 1, "SRT"}, { 2, "SRB"}, { 3, "Auto"}, { 0, NULL } }; void vtp_print(netdissect_options *ndo, const u_char *pptr, const u_int length) { u_int type, len, name_len, tlv_len, tlv_value, mgmtd_len; const u_char *tptr; const struct vtp_vlan_ *vtp_vlan; ndo->ndo_protocol = "vtp"; if (length < VTP_HEADER_LEN) goto invalid; tptr = pptr; ND_TCHECK_LEN(tptr, VTP_HEADER_LEN); type = GET_U_1(tptr + 1); ND_PRINT("VTPv%u, Message %s (0x%02x), length %u", GET_U_1(tptr), tok2str(vtp_message_type_values,"Unknown message type", type), type, length); /* In non-verbose mode, just print version and message type */ if (ndo->ndo_vflag < 1) { goto tcheck_full_packet; } /* verbose mode print all fields */ ND_PRINT("\n\tDomain name: "); mgmtd_len = GET_U_1(tptr + 3); if (mgmtd_len < 1 || mgmtd_len > VTP_DOMAIN_NAME_LEN) { ND_PRINT(" [MgmtD Len %u]", mgmtd_len); goto invalid; } nd_printjnp(ndo, tptr + 4, mgmtd_len); ND_PRINT(", %s: %u", tok2str(vtp_header_values, "Unknown", type), GET_U_1(tptr + 2)); tptr += VTP_HEADER_LEN; switch (type) { case VTP_SUMMARY_ADV: /* * SUMMARY ADVERTISEMENT * * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Version | Code | Followers | MgmtD Len | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Management Domain Name (zero-padded to 32 bytes) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Configuration revision number | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Updater Identity IP address | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Update Timestamp (12 bytes) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | MD5 digest (16 bytes) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * */ ND_PRINT("\n\t Config Rev %x, Updater %s", GET_BE_U_4(tptr), GET_IPADDR_STRING(tptr+4)); tptr += 8; ND_PRINT(", Timestamp 0x%08x 0x%08x 0x%08x", GET_BE_U_4(tptr), GET_BE_U_4(tptr + 4), GET_BE_U_4(tptr + 8)); tptr += VTP_UPDATE_TIMESTAMP_LEN; ND_PRINT(", MD5 digest: %08x%08x%08x%08x", GET_BE_U_4(tptr), GET_BE_U_4(tptr + 4), GET_BE_U_4(tptr + 8), GET_BE_U_4(tptr + 12)); tptr += VTP_MD5_DIGEST_LEN; break; case VTP_SUBSET_ADV: /* * SUBSET ADVERTISEMENT * * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Version | Code | Seq number | MgmtD Len | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Management Domain Name (zero-padded to 32 bytes) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Configuration revision number | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | VLAN info field 1 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | ................ | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | VLAN info field N | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * */ ND_PRINT(", Config Rev %x", GET_BE_U_4(tptr)); /* * VLAN INFORMATION * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | V info len | Status | VLAN type | VLAN name len | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | ISL vlan id | MTU size | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | 802.10 index (SAID) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | VLAN name | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * */ tptr += 4; while ((unsigned)(tptr - pptr) < length) { len = GET_U_1(tptr); if (len == 0) break; ND_TCHECK_LEN(tptr, len); vtp_vlan = (const struct vtp_vlan_*)tptr; if (len < VTP_VLAN_INFO_FIXED_PART_LEN) goto invalid; ND_PRINT("\n\tVLAN info status %s, type %s, VLAN-id %u, MTU %u, SAID 0x%08x, Name ", tok2str(vtp_vlan_status,"Unknown",GET_U_1(vtp_vlan->status)), tok2str(vtp_vlan_type_values,"Unknown",GET_U_1(vtp_vlan->type)), GET_BE_U_2(vtp_vlan->vlanid), GET_BE_U_2(vtp_vlan->mtu), GET_BE_U_4(vtp_vlan->index)); len -= VTP_VLAN_INFO_FIXED_PART_LEN; tptr += VTP_VLAN_INFO_FIXED_PART_LEN; name_len = GET_U_1(vtp_vlan->name_len); if (len < 4*((name_len + 3)/4)) goto invalid; nd_printjnp(ndo, tptr, name_len); /* * Vlan names are aligned to 32-bit boundaries. */ len -= 4*((name_len + 3)/4); tptr += 4*((name_len + 3)/4); /* TLV information follows */ while (len > 0) { /* * Cisco specs say 2 bytes for type + 2 bytes for length; * see https://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 invalid; type = GET_U_1(tptr); tlv_len = GET_U_1(tptr + 1); ND_PRINT("\n\t\t%s (0x%04x) TLV", tok2str(vtp_vlan_tlv_values, "Unknown", type), type); if (len < tlv_len * 2 + 2) { ND_PRINT(" (TLV goes past the end of the packet)"); goto invalid; } ND_TCHECK_LEN(tptr, tlv_len * 2 + 2); /* * We assume the value is a 2-byte integer; the length is * in units of 16-bit words. */ if (tlv_len != 1) { ND_PRINT(" [TLV length %u != 1]", tlv_len); goto invalid; } else { tlv_value = GET_BE_U_2(tptr + 2); switch (type) { case VTP_VLAN_STE_HOP_COUNT: ND_PRINT(", %u", tlv_value); break; case VTP_VLAN_PRUNING: ND_PRINT(", %s (%u)", tlv_value == 1 ? "Enabled" : "Disabled", tlv_value); break; case VTP_VLAN_STP_TYPE: ND_PRINT(", %s (%u)", tok2str(vtp_stp_type_values, "Unknown", tlv_value), tlv_value); break; case VTP_VLAN_BRIDGE_TYPE: ND_PRINT(", %s (%u)", tlv_value == 1 ? "SRB" : "SRT", tlv_value); break; case VTP_VLAN_BACKUP_CRF_MODE: ND_PRINT(", %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; } } break; case VTP_ADV_REQUEST: /* * ADVERTISEMENT REQUEST * * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Version | Code | Reserved | MgmtD Len | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Management Domain Name (zero-padded to 32 bytes) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Start value | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * */ ND_PRINT("\n\tStart value: %u", GET_BE_U_4(tptr)); break; case VTP_JOIN_MESSAGE: /* FIXME - Could not find message format */ break; default: break; } return; invalid: nd_print_invalid(ndo); tcheck_full_packet: ND_TCHECK_LEN(pptr, length); }