*
* 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 1.17 2002-09-05 21:25:38 guy Exp $";
-#endif
+/* \summary: Cisco Discovery Protocol (CDP) printer */
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
+#include <config.h>
-#include <tcpdump-stdinc.h>
+#include "netdissect-stdinc.h"
-#include <stdio.h>
#include <string.h>
-#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 int cdp_print_addr(const u_char *, int);
-static int cdp_print_prefixes(const u_char *, int);
-static unsigned long cdp_get_number(const u_char *, int);
+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);
+}
-void
-cdp_print(const u_char *p, u_int length, u_int caplen)
+static void
+cdp_print_capability(netdissect_options *ndo,
+ const u_char *cp, const u_int len _U_)
{
- u_int i;
- int type, len;
+ uint32_t val = GET_BE_U_4(cp);
+
+ ND_PRINT("(0x%08x): %s", val,
+ bittok2str(cdp_capability_values, "none", val));
+}
- /* Cisco Discovery Protocol */
+/* 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;
- if (caplen < 4) {
- (void)printf("[|cdp]");
- return;
+ 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");
+}
- 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 0x00:
- printf(" Goodbye");
- break;
- case 0x01:
- printf(" DevID '%.*s'", len - 4, p + i + 4);
- break;
- case 0x02:
- printf(" Addr");
- if (cdp_print_addr(p + i + 4, len - 4) < 0)
- goto trunc;
- 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);
+/* 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;
+
+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(netdissect_options *ndo,
+ const u_char *tptr, u_int length)
+{
+ u_int orig_length = length;
+ uint16_t checksum;
+
+ ndo->ndo_protocol = "cdp";
+
+ 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;
+
+ 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:
- if (cdp_print_prefixes(p + i + 4, len - 4) < 0)
- goto trunc;
- break;
- case 0x08: /* guess - not documented */
- printf(" Protocol-Hello option" );
- 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] );
- break;
- case 0x0b: /* guess - not documented */
- printf(" Duplex: %s", p[i + 4] ? "full": "half");
- break;
-/* http://www.cisco.com/univercd/cc/td/doc/product/voice/ata/atarn/186rn21m.htm
- * plus more details from other sources
- */
- case 0x0e: /* incomplete doc. */
- printf(" ATA-186 VoIP VLAN request, app %d, vlan %d",
- p[i + 4], EXTRACT_16BITS(&p[i+4+1]));
- break;
- case 0x0f: /* incomplete doc. */
- printf(" ATA-186 VoIP VLAN assignment" );
- break;
- case 0x10: /* incomplete doc. */
- printf(" power consumption: %1.2fW",
- cdp_get_number(p+i+4, len-4)/1000.0 );
- break;
- case 0x11: /* guess - not documented */
- printf(" MTU %u bytes", EXTRACT_32BITS(&p[i+4]));
- break;
- case 0x12: /* guess - not documented */
- printf(" AVVID trust bitmap 0x%02x", p[i+4] );
- break;
- case 0x13: /* guess - not documented */
- printf(" AVVID untrusted ports CoS: 0x%02x", p[i+4]);
- break;
- case 0x14: /* guess - not documented */
- printf(" System Name: '%.*s'", len - 4,
- p + i + 4);
- break;
- case 0x15: /* guess - not documented */
- printf(" System Object ID (not decoded) "); /* TODO */
- break;
- case 0x16: /* guess - not documented */
- printf(" Management Addresses: ");
- if (cdp_print_addr(p + i + 4, len - 4) < 0)
- goto trunc;
- break;
- case 0x17: /* guess - not documented */
- printf(" Physical Location: 0x%02x/%.*s",
- p[i+4], len - 5, p + i + 5 );
- 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;
+
+ 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;
+ }
}
- /* avoid infinite loop */
- if (len == 0)
- break;
- i += len;
+ 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);
}
/*
#define PT_NLPID 1 /* OSI NLPID */
#define PT_IEEE_802_2 2 /* IEEE 802.2 LLC header */
-static int
-cdp_print_addr(const u_char * p, int l)
+static void
+cdp_print_addr(netdissect_options *ndo,
+ const u_char * p, u_int l)
{
- int pt, pl, al, num;
- const u_char *endp = p + l;
-#ifdef INET6
- static u_char prot_ipv6[] = {
+ u_int num;
+ static const u_char prot_ipv6[] = {
0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
};
-#endif
- num = EXTRACT_32BITS(p);
+ 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)
- goto trunc;
- pt = p[0]; /* type of "protocol" field */
- pl = p[1]; /* length of "protocol" field */
+ 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 (p + pl + 2 > endp)
- goto trunc;
- al = EXTRACT_16BITS(&p[pl]); /* address length */
+ 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 */
- if (pt == PT_NLPID && pl == 1 && *p == 0xcc && al == 4) {
+ 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;
- printf("IPv4 %u.%u.%u.%u", p[0], p[1], p[2], p[3]);
- p += 4;
- }
-#ifdef INET6
- else if (pt == PT_IEEE_802_2 && pl == 8 &&
- memcmp(p, prot_ipv6, 8) == 0 && al == 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("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 += 10;
- if (p + al > endp)
- goto trunc;
-
- printf("IPv6 %s", ip6addr_string(p));
+ 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;
- }
-#endif
- else {
+ l -= al;
+ } else {
/*
* Generic case: just print raw data
*/
- if (p + pl > endp)
- goto trunc;
- printf("pt=0x%02x, pl=%d, pb=", *(p - 2), pl);
- while (pl-- > 0)
- printf(" %02x", *p++);
- if (p + 2 > endp)
- goto trunc;
- al = (*p << 8) + *(p + 1);
- printf(", al=%d, a=", al);
+ 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;
- if (p + al > endp)
- goto trunc;
- 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--;
+ }
}
num--;
if (num)
- printf(" ");
+ ND_PRINT(" ");
}
+ if (l)
+ ND_PRINT(" (%u bytes of stray data)", l);
+ return;
- return 0;
-
-trunc:
- return -1;
+invalid:
+ ND_TCHECK_LEN(p, l);
}
-
-static int
-cdp_print_prefixes(const u_char * p, int l)
+static void
+cdp_print_prefixes(netdissect_options *ndo,
+ const u_char * p, u_int l)
{
- if (l % 5)
- goto trunc;
+ if (l % 5) {
+ ND_PRINT(" [length %u is not a multiple of 5]", l);
+ goto invalid;
+ }
- printf(" IPv4 Prefixes (%d):", l / 5);
+ ND_PRINT(" IPv4 Prefixes (%u):", l / 5);
- while (l > 0) {
- 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;
- return 0;
-
-trunc:
- return -1;
-}
-
-/* read in a <n>-byte number, MSB first
- * (of course this can handle max sizeof(long))
- */
-static unsigned long cdp_get_number(const u_char * p, int l)
-{
- unsigned long res=0;
- while( l>0 )
- {
- res = (res<<8) + *p;
- p++; l--;
- }
- return res;
+invalid:
+ ND_TCHECK_LEN(p, l);
}
projects / tcpdump / blobdiff