X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/a4a78bf5caaddbe59437df15df1a619cc12a1296..5ef0bcb5edd748de9d9af13c40da0395dfdd94e8:/print-cdp.c diff --git a/print-cdp.c b/print-cdp.c index 7ad14274..0ab646e5 100644 --- a/print-cdp.c +++ b/print-cdp.c @@ -21,158 +21,417 @@ * 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 1.3 2000-05-26 09:32:00 itojun Exp $"; -#endif +/* \summary: Cisco Discovery Protocol (CDP) printer */ #ifdef HAVE_CONFIG_H -#include "config.h" +#include #endif -#include -#include - -#include +#include "netdissect-stdinc.h" -#include -#include -#include #include -#include "interface.h" +#include "netdissect.h" #include "addrtoname.h" -#include "extract.h" /* must come after interface.h */ +#include "extract.h" +#include "nlpid.h" -static void cdp_print_addr( const u_char * p, int l ); -static void cdp_print_prefixes( const u_char * p, int l ); -/* - * Returns non-zero IFF it succeeds in printing the header - */ -void -cdp_print(const u_char *p, u_int length, u_int caplen, - const u_char *esrc, const u_char *edst) -{ - int i; - int type, len; +#define CDP_HEADER_LEN 4 +#define CDP_HEADER_VERSION_OFFSET 0 +#define CDP_HEADER_TTL_OFFSET 1 +#define CDP_HEADER_CHECKSUM_OFFSET 2 - /* Cisco Discovery Protocol */ +#define CDP_TLV_HEADER_LEN 4 +#define CDP_TLV_TYPE_OFFSET 0 +#define CDP_TLV_LEN_OFFSET 2 +static const struct tok cdp_tlv_values[] = { + { 0x01, "Device-ID"}, + { 0x02, "Address"}, + { 0x03, "Port-ID"}, + { 0x04, "Capability"}, + { 0x05, "Version String"}, + { 0x06, "Platform"}, + { 0x07, "Prefixes"}, + { 0x08, "Protocol-Hello option"}, + { 0x09, "VTP Management Domain"}, + { 0x0a, "Native VLAN ID"}, + { 0x0b, "Duplex"}, + { 0x0e, "ATA-186 VoIP VLAN assignment"}, + { 0x0f, "ATA-186 VoIP VLAN request"}, + { 0x10, "power consumption"}, + { 0x11, "MTU"}, + { 0x12, "AVVID trust bitmap"}, + { 0x13, "AVVID untrusted ports CoS"}, + { 0x14, "System Name"}, + { 0x15, "System Object ID (not decoded)"}, + { 0x16, "Management Addresses"}, + { 0x17, "Physical Location"}, + { 0, NULL} +}; - if ( caplen < 12 ) { - (void)printf("[|cdp]"); +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 int cdp_print_addr(netdissect_options *, const u_char *, u_int); +static int cdp_print_prefixes(netdissect_options *, const u_char *, u_int); +static unsigned int cdp_get_number(netdissect_options *, const u_char *, u_int); + +void +cdp_print(netdissect_options *ndo, + const u_char *pptr, u_int length, u_int caplen) +{ + u_int type, len, i; + const u_char *tptr; + + ndo->ndo_protocol = "cdp"; + if (caplen < CDP_HEADER_LEN) { + nd_print_trunc(ndo); return; } - i=8; /* CDP data starts at offset 8 */ - printf ("CDP v%d, ttl=%ds", p[i], p[i+1] ); - i+=4; /* skip version, TTL and chksum */ + tptr = pptr; /* temporary pointer */ - while (i < length) { - if ( i+4 > caplen ) { - printf("[!cdp]"); - return; - } - type = (p[i]<<8) + p[i+1]; - len = (p[i+2]<<8) + p[i+3]; + ND_TCHECK_LEN(tptr, CDP_HEADER_LEN); + ND_PRINT("CDPv%u, ttl: %us", + GET_U_1((tptr + CDP_HEADER_VERSION_OFFSET)), + GET_U_1(tptr + CDP_HEADER_TTL_OFFSET)); + if (ndo->ndo_vflag) + ND_PRINT(", checksum: 0x%04x (unverified), length %u", + GET_BE_U_2(tptr + CDP_HEADER_CHECKSUM_OFFSET), + length); + tptr += CDP_HEADER_LEN; - if ( vflag ) - printf( "\n\t%02x/%02x", type, len ); - else - printf( "\n\t" ); + while (tptr < (pptr+length)) { + ND_TCHECK_LEN(tptr, CDP_TLV_HEADER_LEN); /* read out Type and Length */ + 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 */ + if (len < CDP_TLV_HEADER_LEN) { + if (ndo->ndo_vflag) + ND_PRINT("\n\t%s (0x%02x), TLV length: %u byte%s (too short)", + tok2str(cdp_tlv_values,"unknown field type", type), + type, + len, + PLURAL_SUFFIX(len)); /* plural */ + else + ND_PRINT(", %s TLV length %u too short", + tok2str(cdp_tlv_values,"unknown field type", type), + len); + break; + } + tptr += CDP_TLV_HEADER_LEN; + len -= CDP_TLV_HEADER_LEN; - if ( i+len > caplen ) { - printf("[!cdp]"); - return; - } - - 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 ) - printf( " Version:\n%.*s", len-4, p+i+4 ); - 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; - default: - printf( " unknown field type %02x, len %d", type, len ); - } - - /* avoid infinite loop */ - if (len == 0) - break; - i+=len; + ND_TCHECK_LEN(tptr, len); + + if (ndo->ndo_vflag || type == 1) { /* in non-verbose mode just print Device-ID */ + + if (ndo->ndo_vflag) + ND_PRINT("\n\t%s (0x%02x), value length: %u byte%s: ", + tok2str(cdp_tlv_values,"unknown field type", type), + type, + len, + PLURAL_SUFFIX(len)); /* plural */ + + switch (type) { + + case 0x01: /* Device-ID */ + if (!ndo->ndo_vflag) + ND_PRINT(", Device-ID "); + ND_PRINT("'"); + (void)nd_printn(ndo, tptr, len, NULL); + ND_PRINT("'"); + break; + case 0x02: /* Address */ + if (cdp_print_addr(ndo, tptr, len) < 0) + goto trunc; + break; + case 0x03: /* Port-ID */ + ND_PRINT("'"); + (void)nd_printn(ndo, tptr, len, NULL); + ND_PRINT("'"); + break; + case 0x04: /* Capabilities */ + if (len < 4) + goto trunc; + ND_PRINT("(0x%08x): %s", + GET_BE_U_4(tptr), + bittok2str(cdp_capability_values, "none", GET_BE_U_4(tptr))); + break; + case 0x05: /* Version */ + ND_PRINT("\n\t "); + for (i=0;i 1) { + ND_PRINT("/"); + (void)nd_printn(ndo, tptr + 1, len - 1, NULL); + } + break; + default: + print_unknown_data(ndo, tptr, "\n\t ", len); + break; + } + } + tptr = tptr+len; } + if (ndo->ndo_vflag < 1) + ND_PRINT(", length %u", caplen); + + return; +trunc: + nd_print_trunc(ndo); } -static void -cdp_print_addr( const u_char * p, int l ) +/* + * 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 int +cdp_print_addr(netdissect_options *ndo, + const u_char * p, u_int l) { - int pl, al, num; - const u_char * endp = p+l; - - num = (p[0] << 24) + (p[1]<<16) + (p[2]<<8)+ p[3]; - p+=4; - - printf(" (%d): ", num ); - - while( p < endp && num >= 0) { - pl=*(p+1); - p+=2; - - /* special case: IPv4, protocol type=0xcc, addr. length=4 */ - if ( pl == 1 && *p == 0xcc && - p[1] == 0 && p[2] == 4 ) { - p+=3; - - printf( "IPv4 %d.%d.%d.%d ", p[0], p[1], p[2], p[3] ); - p+=4; - } else { /* generic case: just print raw data */ - printf("pt=0x%02x, pl=%d, pb=", *(p-2), pl); - while( pl-- > 0 ) - printf( " %02x", *p++); - al=(*p << 8) + *(p+1); - printf( ", al=%d, a=", al ); - p+=2; - while( al-- > 0 ) - printf( " %02x", *p++); + u_int pt, pl, al, num; + const u_char *endp = p + l; + static const u_char prot_ipv6[] = { + 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd + }; + + ND_TCHECK_4(p); + if (p + 4 > endp) + goto trunc; + num = GET_BE_U_4(p); + p += 4; + + while (p < endp && num != 0) { + ND_TCHECK_2(p); + if (p + 2 > endp) + goto trunc; + pt = GET_U_1(p); /* type of "protocol" field */ + pl = GET_U_1(p + 1); /* length of "protocol" field */ + p += 2; + + ND_TCHECK_2(p + pl); + if (p + pl + 2 > endp) + goto trunc; + al = GET_BE_U_2(p + pl); /* address length */ + + 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 += 3; + + if (p + 4 > endp) + goto trunc; + ND_PRINT("IPv4 (%u) %s", num, GET_IPADDR_STRING(p)); + p += 4; + } + 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 += 10; + ND_TCHECK_LEN(p, al); + if (p + al > endp) + goto trunc; + + ND_PRINT("IPv6 (%u) %s", num, GET_IP6ADDR_STRING(p)); + p += al; + } + else { + /* + * Generic case: just print raw data + */ + ND_TCHECK_LEN(p, pl); + if (p + pl > endp) + goto trunc; + ND_PRINT("pt=0x%02x, pl=%u, pb=", GET_U_1((p - 2)), + pl); + while (pl != 0) { + ND_PRINT(" %02x", GET_U_1(p)); + p++; + pl--; + } + ND_TCHECK_2(p); + if (p + 2 > endp) + goto trunc; + ND_PRINT(", al=%u, a=", al); + p += 2; + ND_TCHECK_LEN(p, al); + if (p + al > endp) + goto trunc; + while (al != 0) { + ND_PRINT(" %02x", GET_U_1(p)); + p++; + al--; + } } - printf(" "); num--; + if (num) + ND_PRINT(" "); } + + return 0; + +trunc: + return -1; } -static void -cdp_print_prefixes( const u_char * p, int l ) +static int +cdp_print_prefixes(netdissect_options *ndo, + const u_char * p, u_int l) { - printf( " IPv4 Prefixes (%d):", l/5 ); + if (l % 5) + goto trunc; + + ND_PRINT(" IPv4 Prefixes (%u):", l / 5); + + 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; + } - while(l > 0) { - printf( " %d.%d.%d.%d/%d", p[0], p[1], p[2], p[3], p[4] ); - l-=5; p+=5; + return 0; + +trunc: + return -1; +} + +/* read in a -byte number, MSB first + * (of course this can handle max sizeof(int)) + */ +static unsigned int +cdp_get_number(netdissect_options *ndo, const u_char * p, u_int l) +{ + unsigned int res=0; + while( l>0 ) + { + res = (res<<8) + GET_U_1(p); + p++; l--; } + return res; }