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diff --git a/print-vtp.c b/print-vtp.c
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+/*
+ * 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 <carles.kishimoto@gmail.com>
+ */
+
+/* \summary: Cisco VLAN Trunking Protocol (VTP) printer */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#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(" [invalid 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(" (invalid 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);
+}
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