nexmon – Rev 1
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/*
* Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Code by Gert Doering, SpaceNet GmbH, gert@space.net
*
* Reference documentation:
* http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
*/
#define NETDISSECT_REWORKED
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <tcpdump-stdinc.h>
#include <string.h>
#include "interface.h"
#include "addrtoname.h"
#include "extract.h" /* must come after interface.h */
#include "nlpid.h"
static const char tstr[] = "[|cdp]";
#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 request"},
{ 0x0f, "ATA-186 VoIP VLAN assignment"},
{ 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 int cdp_print_addr(netdissect_options *, const u_char *, int);
static int cdp_print_prefixes(netdissect_options *, const u_char *, int);
static unsigned long cdp_get_number(const u_char *, int);
void
cdp_print(netdissect_options *ndo,
const u_char *pptr, u_int length, u_int caplen)
{
int type, len, i, j;
const u_char *tptr;
if (caplen < CDP_HEADER_LEN) {
ND_PRINT((ndo, "%s", tstr));
return;
}
tptr = pptr; /* temporary pointer */
ND_TCHECK2(*tptr, CDP_HEADER_LEN);
ND_PRINT((ndo, "CDPv%u, ttl: %us", *(tptr + CDP_HEADER_VERSION_OFFSET),
*(tptr + CDP_HEADER_TTL_OFFSET)));
if (ndo->ndo_vflag)
ND_PRINT((ndo, ", checksum: 0x%04x (unverified), length %u", EXTRACT_16BITS(tptr+CDP_HEADER_CHECKSUM_OFFSET), length));
tptr += CDP_HEADER_LEN;
while (tptr < (pptr+length)) {
ND_TCHECK2(*tptr, CDP_TLV_HEADER_LEN); /* read out Type and Length */
type = EXTRACT_16BITS(tptr+CDP_TLV_TYPE_OFFSET);
len = EXTRACT_16BITS(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((ndo, "\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((ndo, ", %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;
ND_TCHECK2(*tptr, len);
if (ndo->ndo_vflag || type == 1) { /* in non-verbose mode just print Device-ID */
if (ndo->ndo_vflag)
ND_PRINT((ndo, "\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((ndo, ", Device-ID "));
ND_PRINT((ndo, "'"));
(void)fn_printn(ndo, tptr, len, NULL);
ND_PRINT((ndo, "'"));
break;
case 0x02: /* Address */
if (cdp_print_addr(ndo, tptr, len) < 0)
goto trunc;
break;
case 0x03: /* Port-ID */
ND_PRINT((ndo, "'"));
(void)fn_printn(ndo, tptr, len, NULL);
ND_PRINT((ndo, "'"));
break;
case 0x04: /* Capabilities */
if (len < 4)
goto trunc;
ND_PRINT((ndo, "(0x%08x): %s",
EXTRACT_32BITS(tptr),
bittok2str(cdp_capability_values, "none", EXTRACT_32BITS(tptr))));
break;
case 0x05: /* Version */
ND_PRINT((ndo, "\n\t "));
for (i=0;i<len;i++) {
j = *(tptr+i);
ND_PRINT((ndo, "%c", j));
if (j == 0x0a) /* lets rework the version string to get a nice indentation */
ND_PRINT((ndo, "\t "));
}
break;
case 0x06: /* Platform */
ND_PRINT((ndo, "'"));
(void)fn_printn(ndo, tptr, len, NULL);
ND_PRINT((ndo, "'"));
break;
case 0x07: /* Prefixes */
if (cdp_print_prefixes(ndo, tptr, len) < 0)
goto trunc;
break;
case 0x08: /* Protocol Hello Option - not documented */
break;
case 0x09: /* VTP Mgmt Domain - CDPv2 */
ND_PRINT((ndo, "'"));
(void)fn_printn(ndo, tptr, len, NULL);
ND_PRINT((ndo, "'"));
break;
case 0x0a: /* Native VLAN ID - CDPv2 */
if (len < 2)
goto trunc;
ND_PRINT((ndo, "%d", EXTRACT_16BITS(tptr)));
break;
case 0x0b: /* Duplex - CDPv2 */
if (len < 1)
goto trunc;
ND_PRINT((ndo, "%s", *(tptr) ? "full": "half"));
break;
/* http://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
*/
case 0x0e: /* ATA-186 VoIP VLAN request - incomplete doc. */
if (len < 3)
goto trunc;
ND_PRINT((ndo, "app %d, vlan %d", *(tptr), EXTRACT_16BITS(tptr + 1)));
break;
case 0x10: /* ATA-186 VoIP VLAN assignment - incomplete doc. */
ND_PRINT((ndo, "%1.2fW", cdp_get_number(tptr, len) / 1000.0));
break;
case 0x11: /* MTU - not documented */
if (len < 4)
goto trunc;
ND_PRINT((ndo, "%u bytes", EXTRACT_32BITS(tptr)));
break;
case 0x12: /* AVVID trust bitmap - not documented */
if (len < 1)
goto trunc;
ND_PRINT((ndo, "0x%02x", *(tptr)));
break;
case 0x13: /* AVVID untrusted port CoS - not documented */
if (len < 1)
goto trunc;
ND_PRINT((ndo, "0x%02x", *(tptr)));
break;
case 0x14: /* System Name - not documented */
ND_PRINT((ndo, "'"));
(void)fn_printn(ndo, tptr, len, NULL);
ND_PRINT((ndo, "'"));
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((ndo, "0x%02x", *(tptr)));
if (len > 1) {
ND_PRINT((ndo, "/"));
(void)fn_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((ndo, ", length %u", caplen));
return;
trunc:
ND_PRINT((ndo, "%s", tstr));
}
/*
* 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, int l)
{
int pt, pl, al, num;
const u_char *endp = p + l;
#ifdef INET6
static const u_char prot_ipv6[] = {
0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
};
#endif
ND_TCHECK2(*p, 4);
if (p + 4 > endp)
goto trunc;
num = EXTRACT_32BITS(p);
p += 4;
while (p < endp && num >= 0) {
ND_TCHECK2(*p, 2);
if (p + 2 > endp)
goto trunc;
pt = p[0]; /* type of "protocol" field */
pl = p[1]; /* length of "protocol" field */
p += 2;
ND_TCHECK2(p[pl], 2);
if (p + pl + 2 > endp)
goto trunc;
al = EXTRACT_16BITS(&p[pl]); /* address length */
if (pt == PT_NLPID && pl == 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;
ND_TCHECK2(*p, 4);
if (p + 4 > endp)
goto trunc;
ND_PRINT((ndo, "IPv4 (%u) %s", num, ipaddr_string(ndo, p)));
p += 4;
}
#ifdef INET6
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_TCHECK2(*p, al);
if (p + al > endp)
goto trunc;
ND_PRINT((ndo, "IPv6 (%u) %s", num, ip6addr_string(ndo, p)));
p += al;
}
#endif
else {
/*
* Generic case: just print raw data
*/
ND_TCHECK2(*p, pl);
if (p + pl > endp)
goto trunc;
ND_PRINT((ndo, "pt=0x%02x, pl=%d, pb=", *(p - 2), pl));
while (pl-- > 0)
ND_PRINT((ndo, " %02x", *p++));
ND_TCHECK2(*p, 2);
if (p + 2 > endp)
goto trunc;
al = (*p << 8) + *(p + 1);
ND_PRINT((ndo, ", al=%d, a=", al));
p += 2;
ND_TCHECK2(*p, al);
if (p + al > endp)
goto trunc;
while (al-- > 0)
ND_PRINT((ndo, " %02x", *p++));
}
num--;
if (num)
ND_PRINT((ndo, " "));
}
return 0;
trunc:
return -1;
}
static int
cdp_print_prefixes(netdissect_options *ndo,
const u_char * p, int l)
{
if (l % 5)
goto trunc;
ND_PRINT((ndo, " IPv4 Prefixes (%d):", l / 5));
while (l > 0) {
ND_PRINT((ndo, " %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], 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(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;
}