*
* 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"
+#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"
+#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_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}
+};
+
+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(const u_char *, int);
-static void cdp_print_prefixes(const u_char *, int);
+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(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 *pptr, u_int length, u_int caplen)
{
- int i;
- int type, len;
+ u_int type, len, i;
+ const u_char *tptr;
- /* Cisco Discovery Protocol */
-
- if (caplen < 4) {
- (void)printf("[|cdp]");
+ ndo->ndo_protocol = "cdp";
+ if (caplen < CDP_HEADER_LEN) {
+ nd_print_trunc(ndo);
return;
}
- 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 */
+ tptr = pptr; /* temporary pointer */
- while (i < length) {
- if (i + 4 > caplen)
- goto trunc;
- 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 > 1)
- 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 (vflag)
- printf(" %02x/%02x", type, len);
+ ND_TCHECK_LEN(tptr, len);
- if (i + len > caplen)
- goto trunc;
+ if (ndo->ndo_vflag || type == 1) { /* in non-verbose mode just print Device-ID */
- switch (type) {
- case 0x01:
- printf(" DevID '%.*s'", len - 4, p + i + 4);
+ 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:
- printf(" Addr");
- cdp_print_addr(p + i + 4, len - 4);
+ case 0x02: /* Address */
+ if (cdp_print_addr(ndo, tptr, len) < 0)
+ goto trunc;
break;
- case 0x03:
- printf(" PortID '%.*s'", len - 4, p + i + 4);
+ case 0x03: /* Port-ID */
+ ND_PRINT("'");
+ (void)nd_printn(ndo, tptr, len, NULL);
+ ND_PRINT("'");
break;
- case 0x04:
- printf(" CAP 0x%02x", (unsigned) p[i + 7]);
+ 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:
- if (vflag > 1)
- printf(" Version:\n%.*s", len - 4, p + i + 4);
- else
- printf(" Version: (suppressed)");
+ case 0x05: /* Version */
+ ND_PRINT("\n\t ");
+ for (i=0;i<len;i++) {
+ u_char c;
+
+ c = GET_U_1(tptr + i);
+ if (c == '\n') /* lets rework the version string to
+ get a nice indentation */
+ ND_PRINT("\n\t ");
+ else
+ fn_print_char(ndo, c);
+ }
break;
- case 0x06:
- printf(" Platform: '%.*s'", len - 4, p + i + 4);
+ case 0x06: /* Platform */
+ ND_PRINT("'");
+ (void)nd_printn(ndo, tptr, len, NULL);
+ ND_PRINT("'");
break;
- case 0x07:
- cdp_print_prefixes(p + i + 4, len - 4);
+ case 0x07: /* Prefixes */
+ if (cdp_print_prefixes(ndo, tptr, len) < 0)
+ goto trunc;
break;
- case 0x09: /* guess - not documented */
- printf(" VTP Management Domain: '%.*s'", len - 4,
- p + i + 4);
+ case 0x08: /* Protocol Hello Option - not documented */
break;
- case 0x0a: /* guess - not documented */
- printf(" Native VLAN ID: %d",
- (p[i + 4] << 8) + p[i + 4 + 1] - 1);
+ case 0x09: /* VTP Mgmt Domain - CDPv2 */
+ ND_PRINT("'");
+ (void)nd_printn(ndo, tptr, len, NULL);
+ ND_PRINT("'");
break;
- case 0x0b: /* guess - not documented */
- printf(" Duplex: %s", p[i + 4] ? "full": "half");
+ case 0x0a: /* Native VLAN ID - CDPv2 */
+ if (len < 2)
+ goto trunc;
+ ND_PRINT("%u", GET_BE_U_2(tptr));
break;
- default:
- printf(" unknown field type %02x, len %d", type, len);
+ case 0x0b: /* Duplex - CDPv2 */
+ if (len < 1)
+ goto trunc;
+ ND_PRINT("%s", GET_U_1(tptr) ? "full": "half");
break;
- }
- /* avoid infinite loop */
- if (len == 0)
+ /* 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.
+ */
+ case 0x0e: /* ATA-186 VoIP VLAN assignment - incomplete doc. */
+ if (len < 3)
+ goto trunc;
+ ND_PRINT("app %u, vlan %u", GET_U_1(tptr),
+ GET_BE_U_2(tptr + 1));
+ break;
+ case 0x0f: /* ATA-186 VoIP VLAN request - incomplete doc. */
+ if (len < 2)
+ goto trunc;
+ if (len == 2)
+ ND_PRINT("unknown 0x%04x", GET_BE_U_2(tptr));
+ else
+ ND_PRINT("app %u, vlan %u", GET_U_1(tptr),
+ GET_BE_U_2(tptr + 1));
+ break;
+ case 0x10: /* Power - not documented */
+ ND_PRINT("%1.2fW", cdp_get_number(ndo, tptr, len) / 1000.0);
+ break;
+ case 0x11: /* MTU - not documented */
+ if (len < 4)
+ goto trunc;
+ ND_PRINT("%u bytes", GET_BE_U_4(tptr));
+ break;
+ case 0x12: /* AVVID trust bitmap - not documented */
+ if (len < 1)
+ goto trunc;
+ ND_PRINT("0x%02x", GET_U_1(tptr));
break;
- i += len;
+ case 0x13: /* AVVID untrusted port CoS - not documented */
+ if (len < 1)
+ goto trunc;
+ ND_PRINT("0x%02x", GET_U_1(tptr));
+ break;
+ case 0x14: /* System Name - not documented */
+ ND_PRINT("'");
+ (void)nd_printn(ndo, tptr, len, NULL);
+ ND_PRINT("'");
+ break;
+ case 0x16: /* System Object ID - not documented */
+ if (cdp_print_addr(ndo, tptr, len) < 0)
+ goto trunc;
+ break;
+ case 0x17: /* Physical Location - not documented */
+ if (len < 1)
+ goto trunc;
+ ND_PRINT("0x%02x", GET_U_1(tptr));
+ if (len > 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:
- printf("[|cdp]");
+ 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;
+ 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
+ };
- num = (p[0] << 24) + (p[1] << 16) + (p[2] << 8) + p[3];
+ ND_TCHECK_4(p);
+ if (p + 4 > endp)
+ goto trunc;
+ num = GET_BE_U_4(p);
p += 4;
- printf(" (%d): ", num);
-
- while (p < endp && num >= 0) {
- if (p + 2 >= endp)
- break;
- pl = p[1];
+ 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;
- /* 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;
+ 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;
- printf("IPv4 %u.%u.%u.%u ", p[0], p[1], p[2], p[3]);
+ if (p + 4 > endp)
+ goto trunc;
+ ND_PRINT("IPv4 (%u) %s", num, GET_IPADDR_STRING(p));
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);
+ }
+ 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;
- while (al-- > 0)
- printf(" %02x", *p++);
+ 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) {
- if (l < 5)
- break;
- 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;
}
+
+ return 0;
+
+trunc:
+ return -1;
+}
+
+/* read in a <n>-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;
}
projects / tcpdump / blobdiff