X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/49b23c5a9b0198bb382dcf43c458d46fcf2fa809..HEAD:/print-vtp.c diff --git a/print-vtp.c b/print-vtp.c index 285beb96..82dfe2b3 100644 --- a/print-vtp.c +++ b/print-vtp.c @@ -13,21 +13,19 @@ * 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 + * 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 */ -#ifdef HAVE_CONFIG_H -#include "config.h" -#endif +#include -#include +#include "netdissect-stdinc.h" +#define ND_LONGJMP_FROM_TCHECK #include "netdissect.h" #include "addrtoname.h" #include "extract.h" @@ -36,7 +34,7 @@ #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 @@ -44,13 +42,13 @@ #define VTP_JOIN_MESSAGE 0x04 struct vtp_vlan_ { - uint8_t len; - uint8_t status; - uint8_t type; - uint8_t name_len; - uint16_t vlanid; - uint16_t mtu; - uint32_t index; + 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[] = { @@ -117,43 +115,44 @@ static const struct tok vtp_stp_type_values[] = { }; void -vtp_print (netdissect_options *ndo, - const u_char *pptr, u_int length) +vtp_print(netdissect_options *ndo, + const u_char *pptr, const u_int length) { - int type, len, tlv_len, tlv_value, mgmtd_len; + 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 trunc; + goto invalid; tptr = pptr; - ND_TCHECK2(*tptr, VTP_HEADER_LEN); + ND_TCHECK_LEN(tptr, VTP_HEADER_LEN); - type = *(tptr+1); - ND_PRINT((ndo, "VTPv%u, Message %s (0x%02x), length %u", - *tptr, + 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)); + length); /* In non-verbose mode, just print version and message type */ if (ndo->ndo_vflag < 1) { - return; + goto tcheck_full_packet; } /* verbose mode print all fields */ - ND_PRINT((ndo, "\n\tDomain name: ")); - mgmtd_len = *(tptr + 3); - if (mgmtd_len < 1 || mgmtd_len > 32) { - ND_PRINT((ndo, " [invalid MgmtD Len %d]", mgmtd_len)); - return; + 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; } - fn_printzp(ndo, tptr + 4, mgmtd_len, NULL); - ND_PRINT((ndo, ", %s: %u", + nd_printjnp(ndo, tptr + 4, mgmtd_len); + ND_PRINT(", %s: %u", tok2str(vtp_header_values, "Unknown", type), - *(tptr+2))); + GET_U_1(tptr + 2)); tptr += VTP_HEADER_LEN; @@ -181,23 +180,20 @@ vtp_print (netdissect_options *ndo, * */ - ND_TCHECK2(*tptr, 8); - ND_PRINT((ndo, "\n\t Config Rev %x, Updater %s", - EXTRACT_32BITS(tptr), - ipaddr_string(ndo, tptr+4))); + ND_PRINT("\n\t Config Rev %x, Updater %s", + GET_BE_U_4(tptr), + GET_IPADDR_STRING(tptr+4)); tptr += 8; - ND_TCHECK2(*tptr, VTP_UPDATE_TIMESTAMP_LEN); - ND_PRINT((ndo, ", Timestamp 0x%08x 0x%08x 0x%08x", - EXTRACT_32BITS(tptr), - EXTRACT_32BITS(tptr + 4), - EXTRACT_32BITS(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_TCHECK2(*tptr, VTP_MD5_DIGEST_LEN); - ND_PRINT((ndo, ", MD5 digest: %08x%08x%08x%08x", - EXTRACT_32BITS(tptr), - EXTRACT_32BITS(tptr + 4), - EXTRACT_32BITS(tptr + 8), - EXTRACT_32BITS(tptr + 12))); + 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; @@ -223,7 +219,7 @@ vtp_print (netdissect_options *ndo, * */ - ND_PRINT((ndo, ", Config Rev %x", EXTRACT_32BITS(tptr))); + ND_PRINT(", Config Rev %x", GET_BE_U_4(tptr)); /* * VLAN INFORMATION @@ -241,98 +237,115 @@ vtp_print (netdissect_options *ndo, */ tptr += 4; - while (tptr < (pptr+length)) { + while ((unsigned)(tptr - pptr) < length) { - len = *tptr; + len = GET_U_1(tptr); if (len == 0) break; - ND_TCHECK2(*tptr, len); + ND_TCHECK_LEN(tptr, len); vtp_vlan = (const struct vtp_vlan_*)tptr; - 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), - tok2str(vtp_vlan_type_values,"Unknown",vtp_vlan->type), - 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); + 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) { + 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 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. */ - type = *tptr; - tlv_len = *(tptr+1); + if (len < 2) + goto invalid; + type = GET_U_1(tptr); + tlv_len = GET_U_1(tptr + 1); - ND_PRINT((ndo, "\n\t\t%s (0x%04x) TLV", + ND_PRINT("\n\t\t%s (0x%04x) TLV", tok2str(vtp_vlan_tlv_values, "Unknown", type), - type)); + type); - /* - * infinite loop check - */ - if (type == 0 || tlv_len == 0) { - return; + 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); - 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(" [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; @@ -356,8 +369,7 @@ vtp_print (netdissect_options *ndo, * */ - ND_TCHECK2(*tptr, 4); - ND_PRINT((ndo, "\n\tStart value: %u", EXTRACT_32BITS(tptr))); + ND_PRINT("\n\tStart value: %u", GET_BE_U_4(tptr)); break; case VTP_JOIN_MESSAGE: @@ -371,13 +383,8 @@ vtp_print (netdissect_options *ndo, return; - trunc: - ND_PRINT((ndo, "[|vtp]")); +invalid: + nd_print_invalid(ndo); +tcheck_full_packet: + ND_TCHECK_LEN(pptr, length); } - -/* - * Local Variables: - * c-style: whitesmith - * c-basic-offset: 4 - * End: - */