The Tcpdump Group git mirrors - tcpdump/blobdiff

* Code by Gert Doering, SpaceNet GmbH, [email protected]

*

* Reference documentation:

* Code by Gert Doering, SpaceNet GmbH, [email protected]

*

* 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 1.7 2001-06-15 07:58:28 itojun Exp $";

-#endif

+/* \summary: Cisco Discovery Protocol (CDP) printer */

#ifdef HAVE_CONFIG_H

-#include "config.h"

+#include <config.h>

#endif

-#include <sys/param.h>

-#include <sys/time.h>

-

-#include <netinet/in.h>

+#include "netdissect-stdinc.h"

-#include <ctype.h>

-#include <netdb.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 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,

- const u_char *esrc, const u_char *edst)

+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_)

{

- int i;

- int type, len;

+ ND_PRINT("%s", GET_U_1(cp) ? "full": "half");

+}

- /* Cisco Discovery Protocol */

+/* 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));

+}

- if (caplen < 4) {

- (void)printf("[|cdp]");

- return;

+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);

}

+}

+

+struct cdp_tlvinfo {

+ const char *name;

+ void (*printer)(netdissect_options *ndo, const u_char *, u_int);

+ int min_len, max_len;

+};

+

+#define T_DEV_ID 0x01

+#define T_MAX 0x17

+static const struct cdp_tlvinfo cdptlvs[T_MAX + 1] = {

+ /* 0x00 */

+ [ T_DEV_ID ] = { "Device-ID", cdp_print_string, -1, -1 },

+ [ 0x02 ] = { "Address", cdp_print_addr, -1, -1 },

+ [ 0x03 ] = { "Port-ID", cdp_print_string, -1, -1 },

+ [ 0x04 ] = { "Capability", cdp_print_capability, 4, 4 },

+ [ 0x05 ] = { "Version String", cdp_print_version, -1, -1 },

+ [ 0x06 ] = { "Platform", cdp_print_string, -1, -1 },

+ [ 0x07 ] = { "Prefixes", cdp_print_prefixes, -1, -1 },

+ /* not documented */

+ [ 0x08 ] = { "Protocol-Hello option", NULL, -1, -1 },

+ /* CDPv2 */

+ [ 0x09 ] = { "VTP Management Domain", cdp_print_string, -1, -1 },

+ /* CDPv2 */

+ [ 0x0a ] = { "Native VLAN ID", cdp_print_uint16, 2, 2 },

+ /* CDPv2 */

+ [ 0x0b ] = { "Duplex", cdp_print_duplex, 1, 1 },

+ /* 0x0c */

+ /* 0x0d */

+ /* incomplete doc. */

+ [ 0x0e ] = { "ATA-186 VoIP VLAN assignment", cdp_print_ata186, 3, 3 },

+ /* incomplete doc. */

+ [ 0x0f ] = { "ATA-186 VoIP VLAN request", cdp_print_ata186, 2, 3 },

+ /* not documented */

+ [ 0x10 ] = { "power consumption", cdp_print_power, 1, 3 },

+ /* not documented */

+ [ 0x11 ] = { "MTU", cdp_print_mtu, 4, 4 },

+ /* not documented */

+ [ 0x12 ] = { "AVVID trust bitmap", cdp_print_uint8x, 1, 1 },

+ /* not documented */

+ [ 0x13 ] = { "AVVID untrusted ports CoS", cdp_print_uint8x, 1, 1 },

+ /* not documented */

+ [ 0x14 ] = { "System Name", cdp_print_string, -1, -1 },

+ /* not documented */

+ [ 0x15 ] = { "System Object ID (not decoded)", NULL, -1, -1 },

+ [ 0x16 ] = { "Management Addresses", cdp_print_addr, 4, -1 },

+ /* not documented */

+ [ 0x17 ] = { "Physical Location", cdp_print_phys_loc, 1, -1 },

+};

+

+void

+cdp_print(netdissect_options *ndo,

+ const u_char *tptr, u_int length)

+{

+ u_int orig_length = length;

+ uint16_t checksum;

- 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");

- 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);

+ 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;

+ u_char 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";

+ if (len < CDP_TLV_HEADER_LEN) {

+ if (ndo->ndo_vflag)

+ ND_PRINT("\n\t%s (0x%02x), 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 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;

+

+ /* In non-verbose mode just print Device-ID. */

+ if (!ndo->ndo_vflag && type == T_DEV_ID)

+ ND_PRINT(", Device-ID ");

+ else if (ndo->ndo_vflag)

+ ND_PRINT("\n\t%s (0x%02x), value length: %u byte%s: ",

+ name, type, len, PLURAL_SUFFIX(len));

+

+ 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 || type == T_DEV_ID) {

+ 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 (!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);

}

-static int

-cdp_print_addr(const u_char * p, int l)

-{

- int pl, al, num;

- const u_char *endp = p + 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 */

- num = (p[0] << 24) + (p[1] << 16) + (p[2] << 8) + p[3];

+static void

+cdp_print_addr(netdissect_options *ndo,

+ const u_char * p, u_int l)

+{

+ u_int num;

+ static const u_char prot_ipv6[] = {

+ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd

+ };

+

+ if (l < 4) {

+ ND_PRINT(" (not enough space for num)");

+ goto invalid;

+ }

+ 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;

- 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;

- /* special case: IPv4, protocol type=0xcc, addr. length=4 */

- if (p + 3 >= endp)

- goto trunc;

- if (pl == 1 && *p == 0xcc && p[1] == 0 && p[2] == 4) {

- if (p + 7 >= endp)

- goto trunc;

- 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)

- goto trunc;

- 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)

- goto trunc;

- printf(", al=%d, a=", al);

+ 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 && 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;

- 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]);

+ 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;

}

l -= 5;

p += 5;

}

+ return;

- return 0;

-

-trunc:

- return -1;

+invalid:

+ ND_TCHECK_LEN(p, l);

}