/* * Copyright (c) 2000 Lennert Buytenhek * * This software may be distributed either under the terms of the * BSD-style license that accompanies tcpdump or the GNU General * Public License * * Contributed by Lennert Buytenhek */ /* \summary: IEEE 802.1d Spanning Tree Protocol (STP) printer */ #include #include "netdissect-stdinc.h" #include #include "netdissect.h" #include "extract.h" #define RSTP_EXTRACT_PORT_ROLE(x) (((x)&0x0C)>>2) /* STP timers are expressed in multiples of 1/256th second */ #define STP_TIME_BASE 256 #define STP_BPDU_MSTP_MIN_LEN 102 struct stp_bpdu_ { nd_uint16_t protocol_id; nd_uint8_t protocol_version; nd_uint8_t bpdu_type; nd_uint8_t flags; nd_byte root_id[8]; nd_uint32_t root_path_cost; nd_byte bridge_id[8]; nd_uint16_t port_id; nd_uint16_t message_age; nd_uint16_t max_age; nd_uint16_t hello_time; nd_uint16_t forward_delay; nd_uint8_t v1_length; }; #define STP_PROTO_REGULAR 0x00 #define STP_PROTO_RAPID 0x02 #define STP_PROTO_MSTP 0x03 #define STP_PROTO_SPB 0x04 static const struct tok stp_proto_values[] = { { STP_PROTO_REGULAR, "802.1d" }, { STP_PROTO_RAPID, "802.1w" }, { STP_PROTO_MSTP, "802.1s" }, { STP_PROTO_SPB, "802.1aq" }, { 0, NULL} }; #define STP_BPDU_TYPE_CONFIG 0x00 #define STP_BPDU_TYPE_RSTP 0x02 #define STP_BPDU_TYPE_TOPO_CHANGE 0x80 static const struct tok stp_bpdu_flag_values[] = { { 0x01, "Topology change" }, { 0x02, "Proposal" }, { 0x10, "Learn" }, { 0x20, "Forward" }, { 0x40, "Agreement" }, { 0x80, "Topology change ACK" }, { 0, NULL} }; static const struct tok stp_bpdu_type_values[] = { { STP_BPDU_TYPE_CONFIG, "Config" }, { STP_BPDU_TYPE_RSTP, "Rapid STP" }, { STP_BPDU_TYPE_TOPO_CHANGE, "Topology Change" }, { 0, NULL} }; static const struct tok rstp_obj_port_role_values[] = { { 0x00, "Unknown" }, { 0x01, "Alternate" }, { 0x02, "Root" }, { 0x03, "Designated" }, { 0, NULL} }; static char * stp_print_bridge_id(netdissect_options *ndo, const u_char *p) { static char bridge_id_str[sizeof("pppp.aa:bb:cc:dd:ee:ff")]; snprintf(bridge_id_str, sizeof(bridge_id_str), "%.2x%.2x.%.2x:%.2x:%.2x:%.2x:%.2x:%.2x", GET_U_1(p), GET_U_1(p + 1), GET_U_1(p + 2), GET_U_1(p + 3), GET_U_1(p + 4), GET_U_1(p + 5), GET_U_1(p + 6), GET_U_1(p + 7)); return bridge_id_str; } static void stp_print_config_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, u_int length) { uint8_t bpdu_flags; bpdu_flags = GET_U_1(stp_bpdu->flags); ND_PRINT(", Flags [%s]", bittok2str(stp_bpdu_flag_values, "none", bpdu_flags)); ND_PRINT(", bridge-id %s.%04x, length %u", stp_print_bridge_id(ndo, stp_bpdu->bridge_id), GET_BE_U_2(stp_bpdu->port_id), length); /* in non-verbose mode just print the bridge-id */ if (!ndo->ndo_vflag) { return; } ND_PRINT("\n\tmessage-age %.2fs, max-age %.2fs" ", hello-time %.2fs, forwarding-delay %.2fs", (float) GET_BE_U_2(stp_bpdu->message_age) / STP_TIME_BASE, (float) GET_BE_U_2(stp_bpdu->max_age) / STP_TIME_BASE, (float) GET_BE_U_2(stp_bpdu->hello_time) / STP_TIME_BASE, (float) GET_BE_U_2(stp_bpdu->forward_delay) / STP_TIME_BASE); ND_PRINT("\n\troot-id %s, root-pathcost %u", stp_print_bridge_id(ndo, stp_bpdu->root_id), GET_BE_U_4(stp_bpdu->root_path_cost)); /* Port role is only valid for 802.1w */ if (GET_U_1(stp_bpdu->protocol_version) == STP_PROTO_RAPID) { ND_PRINT(", port-role %s", tok2str(rstp_obj_port_role_values, "Unknown", RSTP_EXTRACT_PORT_ROLE(bpdu_flags))); } } /* * MSTP packet format * Ref. IEEE 802.1Q 2003 Ed. Section 14 * * MSTP BPDU * * 2 - bytes Protocol Id * 1 - byte Protocol Ver. * 1 - byte BPDU type * 1 - byte Flags * 8 - bytes CIST Root Identifier * 4 - bytes CIST External Path Cost * 8 - bytes CIST Regional Root Identifier * 2 - bytes CIST Port Identifier * 2 - bytes Message Age * 2 - bytes Max age * 2 - bytes Hello Time * 2 - bytes Forward delay * 1 - byte Version 1 length. Must be 0 * 2 - bytes Version 3 length * 1 - byte Config Identifier * 32 - bytes Config Name * 2 - bytes Revision level * 16 - bytes Config Digest [MD5] * 4 - bytes CIST Internal Root Path Cost * 8 - bytes CIST Bridge Identifier * 1 - byte CIST Remaining Hops * 16 - bytes MSTI information [Max 64 MSTI, each 16 bytes] * * * SPB BPDU * Ref. IEEE 802.1aq. Section 14 * * 2 - bytes Version 4 length * 1 - byte Aux Config Identifier * 32 - bytes Aux Config Name * 2 - bytes Aux Revision level * 16 - bytes Aux Config Digest [MD5] * 1 - byte (1 - 2) Agreement Number * (3 - 4) Discarded Agreement Number * (5) Agreement Valid Flag * (6) Restricted Role Flag * (7 - 8) Unused sent zero * 1 - byte Unused * 1 - byte (1 - 4) Agreement Digest Format Identifier * (5 - 8) Agreement Digest Format Capabilities * 1 - byte (1 - 4) Agreement Digest Convention Identifier * (5 - 8) Agreement Digest Convention Capabilities * 2 - bytes Agreement Digest Edge Count * 8 - byte Reserved Set * 20 - bytes Computed Topology Digest * * * MSTI Payload * * 1 - byte MSTI flag * 8 - bytes MSTI Regional Root Identifier * 4 - bytes MSTI Regional Path Cost * 1 - byte MSTI Bridge Priority * 1 - byte MSTI Port Priority * 1 - byte MSTI Remaining Hops * */ #define MST_BPDU_MSTI_LENGTH 16 #define MST_BPDU_CONFIG_INFO_LENGTH 64 /* Offsets of fields from the beginning for the packet */ #define MST_BPDU_VER3_LEN_OFFSET 36 #define MST_BPDU_CONFIG_NAME_OFFSET 39 #define MST_BPDU_CONFIG_DIGEST_OFFSET 73 #define MST_BPDU_CIST_INT_PATH_COST_OFFSET 89 #define MST_BPDU_CIST_BRIDGE_ID_OFFSET 93 #define MST_BPDU_CIST_REMAIN_HOPS_OFFSET 101 #define MST_BPDU_MSTI_OFFSET 102 /* Offsets within an MSTI */ #define MST_BPDU_MSTI_ROOT_PRIO_OFFSET 1 #define MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET 9 #define MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET 13 #define MST_BPDU_MSTI_PORT_PRIO_OFFSET 14 #define MST_BPDU_MSTI_REMAIN_HOPS_OFFSET 15 #define SPB_BPDU_MIN_LEN 87 #define SPB_BPDU_CONFIG_NAME_OFFSET 3 #define SPB_BPDU_CONFIG_REV_OFFSET SPB_BPDU_CONFIG_NAME_OFFSET + 32 #define SPB_BPDU_CONFIG_DIGEST_OFFSET SPB_BPDU_CONFIG_REV_OFFSET + 2 #define SPB_BPDU_AGREEMENT_OFFSET SPB_BPDU_CONFIG_DIGEST_OFFSET + 16 #define SPB_BPDU_AGREEMENT_UNUSED_OFFSET SPB_BPDU_AGREEMENT_OFFSET + 1 #define SPB_BPDU_AGREEMENT_FORMAT_OFFSET SPB_BPDU_AGREEMENT_UNUSED_OFFSET + 1 #define SPB_BPDU_AGREEMENT_CON_OFFSET SPB_BPDU_AGREEMENT_FORMAT_OFFSET + 1 #define SPB_BPDU_AGREEMENT_EDGE_OFFSET SPB_BPDU_AGREEMENT_CON_OFFSET + 1 #define SPB_BPDU_AGREEMENT_RES1_OFFSET SPB_BPDU_AGREEMENT_EDGE_OFFSET + 2 #define SPB_BPDU_AGREEMENT_RES2_OFFSET SPB_BPDU_AGREEMENT_RES1_OFFSET + 4 #define SPB_BPDU_AGREEMENT_DIGEST_OFFSET SPB_BPDU_AGREEMENT_RES2_OFFSET + 4 static void stp_print_mstp_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, u_int length) { const u_char *ptr; uint8_t bpdu_flags; uint16_t v3len; uint16_t len; uint16_t msti; u_int offset; ptr = (const u_char *)stp_bpdu; bpdu_flags = GET_U_1(stp_bpdu->flags); ND_PRINT(", CIST Flags [%s], length %u", bittok2str(stp_bpdu_flag_values, "none", bpdu_flags), length); /* * in non-verbose mode just print the flags. */ if (!ndo->ndo_vflag) { return; } ND_PRINT("\n\tport-role %s, ", tok2str(rstp_obj_port_role_values, "Unknown", RSTP_EXTRACT_PORT_ROLE(bpdu_flags))); ND_PRINT("CIST root-id %s, CIST ext-pathcost %u", stp_print_bridge_id(ndo, stp_bpdu->root_id), GET_BE_U_4(stp_bpdu->root_path_cost)); ND_PRINT("\n\tCIST regional-root-id %s, ", stp_print_bridge_id(ndo, stp_bpdu->bridge_id)); ND_PRINT("CIST port-id %04x,", GET_BE_U_2(stp_bpdu->port_id)); ND_PRINT("\n\tmessage-age %.2fs, max-age %.2fs" ", hello-time %.2fs, forwarding-delay %.2fs", (float) GET_BE_U_2(stp_bpdu->message_age) / STP_TIME_BASE, (float) GET_BE_U_2(stp_bpdu->max_age) / STP_TIME_BASE, (float) GET_BE_U_2(stp_bpdu->hello_time) / STP_TIME_BASE, (float) GET_BE_U_2(stp_bpdu->forward_delay) / STP_TIME_BASE); ND_PRINT("\n\tv3len %u, ", GET_BE_U_2(ptr + MST_BPDU_VER3_LEN_OFFSET)); ND_PRINT("MCID Name "); nd_printjnp(ndo, ptr + MST_BPDU_CONFIG_NAME_OFFSET, 32); ND_PRINT(", rev %u," "\n\t\tdigest %08x%08x%08x%08x, ", GET_BE_U_2(ptr + MST_BPDU_CONFIG_NAME_OFFSET + 32), GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET), GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 4), GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 8), GET_BE_U_4(ptr + MST_BPDU_CONFIG_DIGEST_OFFSET + 12)); ND_PRINT("CIST int-root-pathcost %u,", GET_BE_U_4(ptr + MST_BPDU_CIST_INT_PATH_COST_OFFSET)); ND_PRINT("\n\tCIST bridge-id %s, ", stp_print_bridge_id(ndo, ptr + MST_BPDU_CIST_BRIDGE_ID_OFFSET)); ND_PRINT("CIST remaining-hops %u", GET_U_1(ptr + MST_BPDU_CIST_REMAIN_HOPS_OFFSET)); /* Dump all MSTI's */ v3len = GET_BE_U_2(ptr + MST_BPDU_VER3_LEN_OFFSET); if (v3len > MST_BPDU_CONFIG_INFO_LENGTH) { len = v3len - MST_BPDU_CONFIG_INFO_LENGTH; offset = MST_BPDU_MSTI_OFFSET; while (len >= MST_BPDU_MSTI_LENGTH) { msti = GET_BE_U_2(ptr + offset + MST_BPDU_MSTI_ROOT_PRIO_OFFSET); msti = msti & 0x0FFF; ND_PRINT("\n\tMSTI %u, Flags [%s], port-role %s", msti, bittok2str(stp_bpdu_flag_values, "none", GET_U_1(ptr + offset)), tok2str(rstp_obj_port_role_values, "Unknown", RSTP_EXTRACT_PORT_ROLE(GET_U_1(ptr + offset)))); ND_PRINT("\n\t\tMSTI regional-root-id %s, pathcost %u", stp_print_bridge_id(ndo, ptr + offset + MST_BPDU_MSTI_ROOT_PRIO_OFFSET), GET_BE_U_4(ptr + offset + MST_BPDU_MSTI_ROOT_PATH_COST_OFFSET)); ND_PRINT("\n\t\tMSTI bridge-prio %u, port-prio %u, hops %u", GET_U_1(ptr + offset + MST_BPDU_MSTI_BRIDGE_PRIO_OFFSET) >> 4, GET_U_1(ptr + offset + MST_BPDU_MSTI_PORT_PRIO_OFFSET) >> 4, GET_U_1(ptr + offset + MST_BPDU_MSTI_REMAIN_HOPS_OFFSET)); len -= MST_BPDU_MSTI_LENGTH; offset += MST_BPDU_MSTI_LENGTH; } } } static void stp_print_spb_bpdu(netdissect_options *ndo, const struct stp_bpdu_ *stp_bpdu, u_int offset) { const u_char *ptr; /* * in non-verbose mode don't print anything. */ if (!ndo->ndo_vflag) { return; } ptr = (const u_char *)stp_bpdu; ND_PRINT("\n\tv4len %u, ", GET_BE_U_2(ptr + offset)); ND_PRINT("AUXMCID Name "); nd_printjnp(ndo, ptr + offset + SPB_BPDU_CONFIG_NAME_OFFSET, 32); ND_PRINT(", Rev %u,\n\t\tdigest %08x%08x%08x%08x", GET_BE_U_2(ptr + offset + SPB_BPDU_CONFIG_REV_OFFSET), GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET), GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 4), GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 8), GET_BE_U_4(ptr + offset + SPB_BPDU_CONFIG_DIGEST_OFFSET + 12)); ND_PRINT("\n\tAgreement num %u, Discarded Agreement num %u, Agreement valid-" "flag %u,\n\tRestricted role-flag: %u, Format id %u cap %u, " "Convention id %u cap %u,\n\tEdge count %u, " "Agreement digest %08x%08x%08x%08x%08x", GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>6, GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>4 & 0x3, GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>3 & 0x1, GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_OFFSET)>>2 & 0x1, GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET)>>4, GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_FORMAT_OFFSET)&0x00ff, GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_CON_OFFSET)>>4, GET_U_1(ptr + offset + SPB_BPDU_AGREEMENT_CON_OFFSET)&0x00ff, GET_BE_U_2(ptr + offset + SPB_BPDU_AGREEMENT_EDGE_OFFSET), GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET), GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 4), GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 8), GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 12), GET_BE_U_4(ptr + offset + SPB_BPDU_AGREEMENT_DIGEST_OFFSET + 16)); } /* * Print 802.1d / 802.1w / 802.1q (mstp) / 802.1aq (spb) packets. */ void stp_print(netdissect_options *ndo, const u_char *p, u_int length) { const struct stp_bpdu_ *stp_bpdu; u_int protocol_version; u_int bpdu_type; u_int mstp_len; u_int spb_len; ndo->ndo_protocol = "stp"; stp_bpdu = (const struct stp_bpdu_*)p; /* Minimum STP Frame size. */ if (length < 4) goto invalid; if (GET_BE_U_2(stp_bpdu->protocol_id)) { ND_PRINT("unknown STP version, length %u", length); return; } protocol_version = GET_U_1(stp_bpdu->protocol_version); ND_PRINT("STP %s", tok2str(stp_proto_values, "Unknown STP protocol (0x%02x)", protocol_version)); switch (protocol_version) { case STP_PROTO_REGULAR: case STP_PROTO_RAPID: case STP_PROTO_MSTP: case STP_PROTO_SPB: break; default: return; } bpdu_type = GET_U_1(stp_bpdu->bpdu_type); ND_PRINT(", %s", tok2str(stp_bpdu_type_values, "Unknown BPDU Type (0x%02x)", bpdu_type)); switch (bpdu_type) { case STP_BPDU_TYPE_CONFIG: if (length < sizeof(struct stp_bpdu_) - 1) { goto invalid; } stp_print_config_bpdu(ndo, stp_bpdu, length); break; case STP_BPDU_TYPE_RSTP: if (protocol_version == STP_PROTO_RAPID) { if (length < sizeof(struct stp_bpdu_)) { goto invalid; } stp_print_config_bpdu(ndo, stp_bpdu, length); } else if (protocol_version == STP_PROTO_MSTP || protocol_version == STP_PROTO_SPB) { if (length < STP_BPDU_MSTP_MIN_LEN) { goto invalid; } if (GET_U_1(stp_bpdu->v1_length) != 0) { /* FIX ME: Emit a message here ? */ goto invalid; } /* Validate v3 length */ mstp_len = GET_BE_U_2(p + MST_BPDU_VER3_LEN_OFFSET); mstp_len += 2; /* length encoding itself is 2 bytes */ if (length < (sizeof(struct stp_bpdu_) + mstp_len)) { goto invalid; } stp_print_mstp_bpdu(ndo, stp_bpdu, length); if (protocol_version == STP_PROTO_SPB) { /* Validate v4 length */ spb_len = GET_BE_U_2(p + MST_BPDU_VER3_LEN_OFFSET + mstp_len); spb_len += 2; if (length < (sizeof(struct stp_bpdu_) + mstp_len + spb_len) || spb_len < SPB_BPDU_MIN_LEN) { goto invalid; } stp_print_spb_bpdu(ndo, stp_bpdu, (sizeof(struct stp_bpdu_) + mstp_len)); } } break; case STP_BPDU_TYPE_TOPO_CHANGE: /* always empty message - just break out */ break; default: break; } return; invalid: nd_print_invalid(ndo); }