X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/e2464187549fd5846ef8cf739d7ba0648e45afb7..HEAD:/print-cdp.c diff --git a/print-cdp.c b/print-cdp.c index 257f5131..0f36337b 100644 --- a/print-cdp.c +++ b/print-cdp.c @@ -21,179 +21,474 @@ * Code by Gert Doering, SpaceNet GmbH, gert@space.net * * Reference documentation: - * http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm + * https://web.archive.org/web/20000914194913/http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.pdf */ -#ifndef lint -static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.6 2001-06-15 07:54:19 itojun Exp $"; -#endif +/* \summary: Cisco Discovery Protocol (CDP) printer */ -#ifdef HAVE_CONFIG_H -#include "config.h" -#endif +#include -#include -#include +#include "netdissect-stdinc.h" -#include - -#include -#include -#include #include -#include "interface.h" +#define ND_LONGJMP_FROM_TCHECK +#include "netdissect.h" #include "addrtoname.h" -#include "extract.h" /* must come after interface.h */ +#include "extract.h" +#include "nlpid.h" + + +#define CDP_HEADER_LEN 4 +#define CDP_HEADER_VERSION_OFFSET 0 +#define CDP_HEADER_TTL_OFFSET 1 +#define CDP_HEADER_CHECKSUM_OFFSET 2 + +#define CDP_TLV_HEADER_LEN 4 +#define CDP_TLV_TYPE_OFFSET 0 +#define CDP_TLV_LEN_OFFSET 2 + +static const struct tok cdp_capability_values[] = { + { 0x01, "Router" }, + { 0x02, "Transparent Bridge" }, + { 0x04, "Source Route Bridge" }, + { 0x08, "L2 Switch" }, + { 0x10, "L3 capable" }, + { 0x20, "IGMP snooping" }, + { 0x40, "L1 capable" }, + { 0, NULL } +}; + +static void cdp_print_addr(netdissect_options *, const u_char *, u_int); +static void cdp_print_prefixes(netdissect_options *, const u_char *, u_int); + +static void +cdp_print_string(netdissect_options *ndo, + const u_char *cp, const u_int len) +{ + ND_PRINT("'"); + nd_printjn(ndo, cp, len); + ND_PRINT("'"); +} + +static void +cdp_print_power(netdissect_options *ndo, + const u_char *cp, const u_int len) +{ + u_int val = 0; + + switch (len) { + case 1: + val = GET_U_1(cp); + break; + case 2: + val = GET_BE_U_2(cp); + break; + case 3: + val = GET_BE_U_3(cp); + break; + } + ND_PRINT("%1.2fW", val / 1000.0); +} + +static void +cdp_print_capability(netdissect_options *ndo, + const u_char *cp, const u_int len _U_) +{ + uint32_t val = GET_BE_U_4(cp); + + ND_PRINT("(0x%08x): %s", val, + bittok2str(cdp_capability_values, "none", val)); +} + +/* Rework the version string to get a nice indentation. */ +static void +cdp_print_version(netdissect_options *ndo, + const u_char *cp, const u_int len) +{ + unsigned i; + + ND_PRINT("\n\t "); + for (i = 0; i < len; i++) { + u_char c = GET_U_1(cp + i); + + if (c == '\n') + ND_PRINT("\n\t "); + else + fn_print_char(ndo, c); + } +} + +static void +cdp_print_uint16(netdissect_options *ndo, + const u_char *cp, const u_int len _U_) +{ + ND_PRINT("%u", GET_BE_U_2(cp)); +} + +static void +cdp_print_duplex(netdissect_options *ndo, + const u_char *cp, const u_int len _U_) +{ + ND_PRINT("%s", GET_U_1(cp) ? "full": "half"); +} + +/* https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cata/186/2_12_m/english/release/notes/186rn21m.html +* plus more details from other sources +* +* There are apparently versions of the request with both +* 2 bytes and 3 bytes of value. The 3 bytes of value +* appear to be a 1-byte application type followed by a +* 2-byte VLAN ID; the 2 bytes of value are unknown +* (they're 0x20 0x00 in some captures I've seen; that +* is not a valid VLAN ID, as VLAN IDs are 12 bits). +* +* The replies all appear to be 3 bytes long. +*/ +static void +cdp_print_ata186(netdissect_options *ndo, + const u_char *cp, const u_int len) +{ + if (len == 2) + ND_PRINT("unknown 0x%04x", GET_BE_U_2(cp)); + else + ND_PRINT("app %u, vlan %u", GET_U_1(cp), GET_BE_U_2(cp + 1)); +} + +static void +cdp_print_mtu(netdissect_options *ndo, + const u_char *cp, const u_int len _U_) +{ + ND_PRINT("%u bytes", GET_BE_U_4(cp)); +} + +static void +cdp_print_uint8x(netdissect_options *ndo, + const u_char *cp, const u_int len _U_) +{ + ND_PRINT("0x%02x", GET_U_1(cp)); +} + +static void +cdp_print_phys_loc(netdissect_options *ndo, + const u_char *cp, const u_int len) +{ + ND_PRINT("0x%02x", GET_U_1(cp)); + if (len > 1) { + ND_PRINT("/"); + nd_printjn(ndo, cp + 1, len - 1); + } +} + +static void +cdp_print_power_avail(netdissect_options *ndo, + const u_char *cp, const u_int len) +{ + ND_PRINT("reqid %u, mgmtid %u", GET_BE_U_2(cp), GET_BE_U_2(cp + 2)); + if (len > 4) { + const u_char *powerp; + u_int powerlen; + + ND_PRINT(", pwravail"); + for (powerp = cp + 4, powerlen = len - 4; + powerlen >= 4; powerp += 4, powerlen -= 4) + ND_PRINT(" %u mW", GET_BE_U_4(powerp)); + } +} + +typedef enum { + VERBOSE_OR_NOT_VERBOSE, + VERBOSE_ONLY +} when_to_print_t; -static void cdp_print_addr(const u_char *, int); -static void cdp_print_prefixes(const u_char *, int); +struct cdp_tlvinfo { + const char *name; + void (*printer)(netdissect_options *ndo, const u_char *, u_int); + when_to_print_t when_to_print; + int min_len, max_len; +}; + +static const struct cdp_tlvinfo cdptlvs[] = { + /* 0x00 */ + [ 0x01 ] = { "Device-ID", cdp_print_string, VERBOSE_OR_NOT_VERBOSE, -1, -1 }, + [ 0x02 ] = { "Address", cdp_print_addr, VERBOSE_ONLY, 4, -1 }, + [ 0x03 ] = { "Port-ID", cdp_print_string, VERBOSE_ONLY, -1, -1 }, + [ 0x04 ] = { "Capability", cdp_print_capability, VERBOSE_ONLY, 4, 4 }, + [ 0x05 ] = { "Version String", cdp_print_version, VERBOSE_ONLY, -1, -1 }, + [ 0x06 ] = { "Platform", cdp_print_string, VERBOSE_ONLY, -1, -1 }, + [ 0x07 ] = { "Prefixes", cdp_print_prefixes, VERBOSE_ONLY, -1, -1 }, + /* not documented */ + [ 0x08 ] = { "Protocol-Hello option", NULL, VERBOSE_ONLY, -1, -1 }, + /* CDPv2 */ + [ 0x09 ] = { "VTP Management Domain", cdp_print_string, VERBOSE_ONLY, -1, -1 }, + /* CDPv2 */ + [ 0x0a ] = { "Native VLAN ID", cdp_print_uint16, VERBOSE_ONLY, 2, 2 }, + /* CDPv2 */ + [ 0x0b ] = { "Duplex", cdp_print_duplex, VERBOSE_ONLY, 1, 1 }, + /* 0x0c */ + /* 0x0d */ + /* incomplete doc. */ + [ 0x0e ] = { "ATA-186 VoIP VLAN assignment", cdp_print_ata186, VERBOSE_ONLY, 3, 3 }, + /* incomplete doc. */ + [ 0x0f ] = { "ATA-186 VoIP VLAN request", cdp_print_ata186, VERBOSE_ONLY, 2, 3 }, + /* not documented */ + [ 0x10 ] = { "power consumption", cdp_print_power, VERBOSE_ONLY, 1, 3 }, + /* not documented */ + [ 0x11 ] = { "MTU", cdp_print_mtu, VERBOSE_ONLY, 4, 4 }, + /* not documented */ + [ 0x12 ] = { "AVVID trust bitmap", cdp_print_uint8x, VERBOSE_ONLY, 1, 1 }, + /* not documented */ + [ 0x13 ] = { "AVVID untrusted ports CoS", cdp_print_uint8x, VERBOSE_ONLY, 1, 1 }, + /* not documented */ + [ 0x14 ] = { "System Name", cdp_print_string, VERBOSE_ONLY, -1, -1 }, + /* not documented */ + [ 0x15 ] = { "System Object ID (not decoded)", NULL, VERBOSE_ONLY, -1, -1 }, + [ 0x16 ] = { "Management Addresses", cdp_print_addr, VERBOSE_ONLY, 4, -1 }, + /* not documented */ + [ 0x17 ] = { "Physical Location", cdp_print_phys_loc, VERBOSE_ONLY, 1, -1 }, + /* not documented */ + [ 0x1a ] = { "Power available", cdp_print_power_avail, VERBOSE_ONLY, 8, -1 }, +}; + +#define T_MAX (sizeof cdptlvs / sizeof cdptlvs[0]) void -cdp_print(const u_char *p, u_int length, u_int caplen, - const u_char *esrc, const u_char *edst) +cdp_print(netdissect_options *ndo, + const u_char *tptr, u_int length) { - int i; - int type, len; + u_int orig_length = length; + uint16_t checksum; - /* Cisco Discovery Protocol */ + ndo->ndo_protocol = "cdp"; - if (caplen < 4) { - (void)printf("[|cdp]"); - return; + if (length < CDP_HEADER_LEN) { + ND_PRINT(" (packet length %u < %u)", length, CDP_HEADER_LEN); + goto invalid; } + ND_PRINT("CDPv%u, ttl: %us", + GET_U_1(tptr + CDP_HEADER_VERSION_OFFSET), + GET_U_1(tptr + CDP_HEADER_TTL_OFFSET)); + checksum = GET_BE_U_2(tptr + CDP_HEADER_CHECKSUM_OFFSET); + if (ndo->ndo_vflag) + ND_PRINT(", checksum: 0x%04x (unverified), length %u", + checksum, orig_length); + tptr += CDP_HEADER_LEN; + length -= CDP_HEADER_LEN; + + while (length) { + u_int type, len; + const struct cdp_tlvinfo *info; + const char *name; + int print_if_not_verbose; + int covered = 0; - i = 0; /* CDP data starts at offset 0 */ - printf("CDP v%u, ttl=%us", p[i], p[i + 1]); - i += 4; /* skip version, TTL and chksum */ - - while (i < length) { - if (i + 4 > caplen) - goto trunc; - type = (p[i] << 8) + p[i + 1]; - len = (p[i + 2] << 8) + p[i + 3]; - - if (vflag > 1) - printf("\n\t"); - - if (vflag) - printf(" %02x/%02x", type, len); - - if (i + len > caplen) - goto trunc; - - switch (type) { - case 0x01: - printf(" DevID '%.*s'", len - 4, p + i + 4); - break; - case 0x02: - printf(" Addr"); - cdp_print_addr(p + i + 4, len - 4); - break; - case 0x03: - printf(" PortID '%.*s'", len - 4, p + i + 4); - break; - case 0x04: - printf(" CAP 0x%02x", (unsigned) p[i + 7]); - break; - case 0x05: - if (vflag > 1) - printf(" Version:\n%.*s", len - 4, p + i + 4); + if (length < CDP_TLV_HEADER_LEN) { + ND_PRINT(" (remaining packet length %u < %u)", + length, CDP_TLV_HEADER_LEN); + goto invalid; + } + type = GET_BE_U_2(tptr + CDP_TLV_TYPE_OFFSET); + len = GET_BE_U_2(tptr + CDP_TLV_LEN_OFFSET); /* object length includes the 4 bytes header length */ + info = type < T_MAX ? &cdptlvs[type] : NULL; + name = (info && info->name) ? info->name : "unknown field type"; + print_if_not_verbose = + (info ? (info->when_to_print == VERBOSE_OR_NOT_VERBOSE) : 0); + if (len < CDP_TLV_HEADER_LEN) { + if (ndo->ndo_vflag) + ND_PRINT("\n\t%s (0x%04x), TLV length: %u byte%s (too short)", + name, type, len, PLURAL_SUFFIX(len)); else - printf(" Version: (suppressed)"); - break; - case 0x06: - printf(" Platform: '%.*s'", len - 4, p + i + 4); - break; - case 0x07: - cdp_print_prefixes(p + i + 4, len - 4); - break; - case 0x09: /* guess - not documented */ - printf(" VTP Management Domain: '%.*s'", len - 4, - p + i + 4); - break; - case 0x0a: /* guess - not documented */ - printf(" Native VLAN ID: %d", - (p[i + 4] << 8) + p[i + 4 + 1] - 1); - break; - case 0x0b: /* guess - not documented */ - printf(" Duplex: %s", p[i + 4] ? "full": "half"); - break; - default: - printf(" unknown field type %02x, len %d", type, len); - break; + ND_PRINT(", %s TLV length %u too short", + name, len); + goto invalid; + } + if (len > length) { + ND_PRINT(" (TLV length %u > %u)", len, length); + goto invalid; } + tptr += CDP_TLV_HEADER_LEN; + length -= CDP_TLV_HEADER_LEN; + len -= CDP_TLV_HEADER_LEN; - /* avoid infinite loop */ - if (len == 0) - break; - i += len; + if (ndo->ndo_vflag) { + /* Print all TLVs when in verbose mode */ + ND_PRINT("\n\t%s (0x%04x), value length: %u byte%s: ", + name, type, len, PLURAL_SUFFIX(len)); + } else { + /* Print only some TLVs when not in verbose mode */ + if (print_if_not_verbose) + ND_PRINT(", %s ", name); + } + + if (info) { + if ((info->min_len > 0 && len < (unsigned)info->min_len) || + (info->max_len > 0 && len > (unsigned)info->max_len)) + ND_PRINT(" (malformed TLV)"); + else if (ndo->ndo_vflag || print_if_not_verbose) { + if (info->printer) + info->printer(ndo, tptr, len); + else + ND_TCHECK_LEN(tptr, len); + /* + * When the type is defined without a printer, + * do not print the hex dump. + */ + covered = 1; + } + } + + if (ndo->ndo_vflag && !covered) { + ND_TCHECK_LEN(tptr, len); + print_unknown_data(ndo, tptr, "\n\t ", len); + } + tptr += len; + length -= len; } + if (ndo->ndo_vflag < 1) + ND_PRINT(", length %u", orig_length); return; - -trunc: - printf("[|cdp]"); +invalid: + nd_print_invalid(ndo); + ND_TCHECK_LEN(tptr, length); } +/* + * Protocol type values. + * + * PT_NLPID means that the protocol type field contains an OSI NLPID. + * + * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2 + * LLC header that specifies that the payload is for that protocol. + */ +#define PT_NLPID 1 /* OSI NLPID */ +#define PT_IEEE_802_2 2 /* IEEE 802.2 LLC header */ + static void -cdp_print_addr(const u_char * p, int l) +cdp_print_addr(netdissect_options *ndo, + const u_char * p, u_int l) { - int pl, al, num; - const u_char *endp = p + l; + u_int num; + static const u_char prot_ipv6[] = { + 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd + }; - num = (p[0] << 24) + (p[1] << 16) + (p[2] << 8) + p[3]; + num = GET_BE_U_4(p); p += 4; + l -= 4; - printf(" (%d): ", num); + while (num) { + u_int pt, pl, al; - while (p < endp && num >= 0) { - if (p + 2 >= endp) - break; - pl = p[1]; + if (l < 2) { + ND_PRINT(" (not enough space for PT+PL)"); + goto invalid; + } + pt = GET_U_1(p); /* type of "protocol" field */ + pl = GET_U_1(p + 1); /* length of "protocol" field */ p += 2; + l -= 2; + + if (l < pl + 2) { + ND_PRINT(" (not enough space for P+AL)"); + goto invalid; + } + /* Skip the protocol for now. */ + al = GET_BE_U_2(p + pl); /* address length */ - /* special case: IPv4, protocol type=0xcc, addr. length=4 */ - if (p + 3 >= endp) - break; - if (pl == 1 && *p == 0xcc && p[1] == 0 && p[2] == 4) { - if (p + 7 >= endp) - break; - p += 3; - - printf("IPv4 %u.%u.%u.%u ", p[0], p[1], p[2], p[3]); - p += 4; - } else { /* generic case: just print raw data */ - if (p + pl >= endp) - break; - printf("pt=0x%02x, pl=%d, pb=", *(p-2), pl); - while (pl-- > 0) - printf(" %02x", *p++); - al = (*p << 8) + *(p + 1); - if (p + 2 + al >= endp) - break; - printf(", al=%d, a=", al); + if (pt == PT_NLPID && pl == 1 && GET_U_1(p) == NLPID_IP && + al == 4) { + /* + * IPv4: protocol type = NLPID, protocol length = 1 + * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4), + * address length = 4 + */ + p += pl + 2; + l -= pl + 2; + /* p is just beyond al now. */ + if (l < al) { + ND_PRINT(" (not enough space for A)"); + goto invalid; + } + ND_PRINT("IPv4 (%u) %s", num, GET_IPADDR_STRING(p)); + p += al; + l -= al; + } else if (pt == PT_IEEE_802_2 && pl == 8 && + memcmp(p, prot_ipv6, 8) == 0 && al == 16) { + /* + * IPv6: protocol type = IEEE 802.2 header, + * protocol length = 8 (size of LLC+SNAP header), + * protocol = LLC+SNAP header with the IPv6 + * Ethertype, address length = 16 + */ + p += pl + 2; + l -= pl + 2; + /* p is just beyond al now. */ + if (l < al) { + ND_PRINT(" (not enough space for A)"); + goto invalid; + } + ND_PRINT("IPv6 (%u) %s", num, GET_IP6ADDR_STRING(p)); + p += al; + l -= al; + } else { + /* + * Generic case: just print raw data + */ + ND_PRINT("pt=0x%02x, pl=%u, pb=", pt, pl); + while (pl != 0) { + ND_PRINT(" %02x", GET_U_1(p)); + p++; + l--; + pl--; + } + ND_PRINT(", al=%u, a=", al); p += 2; - while (al-- > 0) - printf(" %02x", *p++); + l -= 2; + /* p is just beyond al now. */ + if (l < al) { + ND_PRINT(" (not enough space for A)"); + goto invalid; + } + while (al != 0) { + ND_PRINT(" %02x", GET_U_1(p)); + p++; + l--; + al--; + } } - printf(" "); num--; + if (num) + ND_PRINT(" "); } -} + if (l) + ND_PRINT(" (%u bytes of stray data)", l); + return; +invalid: + ND_TCHECK_LEN(p, l); +} static void -cdp_print_prefixes(const u_char * p, int l) +cdp_print_prefixes(netdissect_options *ndo, + const u_char * p, u_int l) { - printf(" IPv4 Prefixes (%d):", l / 5); + if (l % 5) { + ND_PRINT(" [length %u is not a multiple of 5]", l); + goto invalid; + } + + ND_PRINT(" IPv4 Prefixes (%u):", l / 5); - while (l > 0) { - if (l < 5) - break; - printf(" %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]); + while (l != 0) { + ND_PRINT(" %u.%u.%u.%u/%u", + GET_U_1(p), GET_U_1(p + 1), GET_U_1(p + 2), + GET_U_1(p + 3), GET_U_1(p + 4)); l -= 5; p += 5; } + return; + +invalid: + ND_TCHECK_LEN(p, l); }