* Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996

/*
* Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
* 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.
*/

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: print-icmp.c,v 1.14 2024/09/02 16:15:31 christos Exp $");
#endif

/* \summary: Internet Control Message Protocol (ICMP) printer */

#include <config.h>

#include "netdissect-stdinc.h"

#include <stdio.h>
#include <string.h>

#include "netdissect.h"
#include "addrtoname.h"
#include "extract.h"

#include "ip.h"
#include "udp.h"
#include "ipproto.h"
#include "mpls.h"

/*
* Interface Control Message Protocol Definitions.
* Per RFC 792, September 1981.
*/

/*
* Structure of an icmp header.
*/
struct icmp {
nd_uint8_t icmp_type; /* type of message, see below */
nd_uint8_t icmp_code; /* type sub code */
nd_uint16_t icmp_cksum; /* ones complement cksum of struct */
union {
nd_uint8_t ih_pptr; /* ICMP_PARAMPROB */
nd_ipv4 ih_gwaddr; /* ICMP_REDIRECT */
struct ih_idseq {
nd_uint16_t icd_id;
nd_uint16_t icd_seq;
} ih_idseq;
nd_uint32_t ih_void;
} icmp_hun;
#define icmp_pptr icmp_hun.ih_pptr
#define icmp_gwaddr icmp_hun.ih_gwaddr
#define icmp_id icmp_hun.ih_idseq.icd_id
#define icmp_seq icmp_hun.ih_idseq.icd_seq
#define icmp_void icmp_hun.ih_void
union {
struct id_ts {
nd_uint32_t its_otime;
nd_uint32_t its_rtime;
nd_uint32_t its_ttime;
} id_ts;
struct id_ip {
struct ip idi_ip;
/* options and then 64 bits of data */
} id_ip;
nd_uint32_t id_mask;
nd_byte id_data[1];
} icmp_dun;
#define icmp_otime icmp_dun.id_ts.its_otime
#define icmp_rtime icmp_dun.id_ts.its_rtime
#define icmp_ttime icmp_dun.id_ts.its_ttime
#define icmp_ip icmp_dun.id_ip.idi_ip
#define icmp_mask icmp_dun.id_mask
#define icmp_data icmp_dun.id_data
} UNALIGNED;

/*
* Lower bounds on packet lengths for various types.
* For the error advice packets must first insure that the
* packet is large enough to contain the returned ip header.
* Only then can we do the check to see if 64 bits of packet
* data have been returned, since we need to check the returned
* ip header length.
*/
#define ICMP_MINLEN 8 /* abs minimum */
#define ICMP_EXTD_MINLEN (156 - sizeof (struct ip)) /* draft-bonica-internet-icmp-08 */
#define ICMP_TSLEN (8 + 3 * sizeof (uint32_t)) /* timestamp */
#define ICMP_MASKLEN 12 /* address mask */
#define ICMP_ADVLENMIN (8 + sizeof (struct ip) + 8) /* min */
#define ICMP_ADVLEN(p) (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
/* N.B.: must separately check that ip_hl >= 5 */

/*
* Definition of type and code field values.
*/
#define ICMP_ECHOREPLY 0 /* echo reply */
#define ICMP_UNREACH 3 /* dest unreachable, codes: */
#define ICMP_UNREACH_NET 0 /* bad net */
#define ICMP_UNREACH_HOST 1 /* bad host */
#define ICMP_UNREACH_PROTOCOL 2 /* bad protocol */
#define ICMP_UNREACH_PORT 3 /* bad port */
#define ICMP_UNREACH_NEEDFRAG 4 /* IP_DF caused drop */
#define ICMP_UNREACH_SRCFAIL 5 /* src route failed */
#define ICMP_UNREACH_NET_UNKNOWN 6 /* unknown net */
#define ICMP_UNREACH_HOST_UNKNOWN 7 /* unknown host */
#define ICMP_UNREACH_ISOLATED 8 /* src host isolated */
#define ICMP_UNREACH_NET_PROHIB 9 /* prohibited access */
#define ICMP_UNREACH_HOST_PROHIB 10 /* ditto */
#define ICMP_UNREACH_TOSNET 11 /* bad tos for net */
#define ICMP_UNREACH_TOSHOST 12 /* bad tos for host */
#define ICMP_SOURCEQUENCH 4 /* packet lost, slow down */
#define ICMP_REDIRECT 5 /* shorter route, codes: */
#define ICMP_REDIRECT_NET 0 /* for network */
#define ICMP_REDIRECT_HOST 1 /* for host */
#define ICMP_REDIRECT_TOSNET 2 /* for tos and net */
#define ICMP_REDIRECT_TOSHOST 3 /* for tos and host */
#define ICMP_ECHO 8 /* echo service */
#define ICMP_ROUTERADVERT 9 /* router advertisement */
#define ICMP_ROUTERSOLICIT 10 /* router solicitation */
#define ICMP_TIMXCEED 11 /* time exceeded, code: */
#define ICMP_TIMXCEED_INTRANS 0 /* ttl==0 in transit */
#define ICMP_TIMXCEED_REASS 1 /* ttl==0 in reass */
#define ICMP_PARAMPROB 12 /* ip header bad */
#define ICMP_PARAMPROB_OPTABSENT 1 /* req. opt. absent */
#define ICMP_TSTAMP 13 /* timestamp request */
#define ICMP_TSTAMPREPLY 14 /* timestamp reply */
#define ICMP_IREQ 15 /* information request */
#define ICMP_IREQREPLY 16 /* information reply */
#define ICMP_MASKREQ 17 /* address mask request */
#define ICMP_MASKREPLY 18 /* address mask reply */

#define ICMP_MAXTYPE 18

#define ICMP_ERRTYPE(type) \
((type) == ICMP_UNREACH || (type) == ICMP_SOURCEQUENCH || \
(type) == ICMP_REDIRECT || (type) == ICMP_TIMXCEED || \
(type) == ICMP_PARAMPROB)
#define ICMP_MULTIPART_EXT_TYPE(type) \
((type) == ICMP_UNREACH || \
(type) == ICMP_TIMXCEED || \
(type) == ICMP_PARAMPROB)
/* rfc1700 */
#ifndef ICMP_UNREACH_NET_UNKNOWN
#define ICMP_UNREACH_NET_UNKNOWN 6 /* destination net unknown */
#endif
#ifndef ICMP_UNREACH_HOST_UNKNOWN
#define ICMP_UNREACH_HOST_UNKNOWN 7 /* destination host unknown */
#endif
#ifndef ICMP_UNREACH_ISOLATED
#define ICMP_UNREACH_ISOLATED 8 /* source host isolated */
#endif
#ifndef ICMP_UNREACH_NET_PROHIB
#define ICMP_UNREACH_NET_PROHIB 9 /* admin prohibited net */
#endif
#ifndef ICMP_UNREACH_HOST_PROHIB
#define ICMP_UNREACH_HOST_PROHIB 10 /* admin prohibited host */
#endif
#ifndef ICMP_UNREACH_TOSNET
#define ICMP_UNREACH_TOSNET 11 /* tos prohibited net */
#endif
#ifndef ICMP_UNREACH_TOSHOST
#define ICMP_UNREACH_TOSHOST 12 /* tos prohibited host */
#endif

/* rfc1716 */
#ifndef ICMP_UNREACH_FILTER_PROHIB
#define ICMP_UNREACH_FILTER_PROHIB 13 /* admin prohibited filter */
#endif
#ifndef ICMP_UNREACH_HOST_PRECEDENCE
#define ICMP_UNREACH_HOST_PRECEDENCE 14 /* host precedence violation */
#endif
#ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
#define ICMP_UNREACH_PRECEDENCE_CUTOFF 15 /* precedence cutoff */
#endif

/* Most of the icmp types */
static const struct tok icmp2str[] = {
{ ICMP_ECHOREPLY, "echo reply" },
{ ICMP_SOURCEQUENCH, "source quench" },
{ ICMP_ECHO, "echo request" },
{ ICMP_ROUTERSOLICIT, "router solicitation" },
{ ICMP_TSTAMP, "time stamp request" },
{ ICMP_TSTAMPREPLY, "time stamp reply" },
{ ICMP_IREQ, "information request" },
{ ICMP_IREQREPLY, "information reply" },
{ ICMP_MASKREQ, "address mask request" },
{ 0, NULL }
};

/* rfc1191 */
struct mtu_discovery {
nd_uint16_t unused;
nd_uint16_t nexthopmtu;
};

/* rfc1256 */
struct ih_rdiscovery {
nd_uint8_t ird_addrnum;
nd_uint8_t ird_addrsiz;
nd_uint16_t ird_lifetime;
};

struct id_rdiscovery {
nd_uint32_t ird_addr;
nd_uint32_t ird_pref;
};

/*
* RFC 4884 - Extended ICMP to Support Multi-Part Messages
*
* This is a general extension mechanism, based on the mechanism
* in draft-bonica-icmp-mpls-02 ICMP Extensions for MultiProtocol
* Label Switching.
*
* The Destination Unreachable, Time Exceeded
* and Parameter Problem messages are slightly changed as per
* the above RFC. A new Length field gets added to give
* the caller an idea about the length of the piggybacked
* IP packet before the extension header starts.
*
* The Length field represents length of the padded "original datagram"
* field measured in 32-bit words.
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Type | Code | Checksum |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | unused | Length | unused |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Internet Header + leading octets of original datagram |
* | |
* | // |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/

struct icmp_ext_t {
nd_uint8_t icmp_type;
nd_uint8_t icmp_code;
nd_uint16_t icmp_checksum;
nd_byte icmp_reserved;
nd_uint8_t icmp_length;
nd_byte icmp_reserved2[2];
nd_byte icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
nd_byte icmp_ext_version_res[2];
nd_uint16_t icmp_ext_checksum;
nd_byte icmp_ext_data[1];
};

/*
* Extract version from the first octet of icmp_ext_version_res.
*/
#define ICMP_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)

/*
* Current version.
*/
#define ICMP_EXT_VERSION 2

/*
* Extension object class numbers.
*
* Class 1 dates back to draft-bonica-icmp-mpls-02.
*/

/* rfc4950 */
#define MPLS_STACK_ENTRY_OBJECT_CLASS 1

struct icmp_multipart_ext_object_header_t {
nd_uint16_t length;
nd_uint8_t class_num;
nd_uint8_t ctype;
};

static const struct tok icmp_multipart_ext_obj_values[] = {
{ 1, "MPLS Stack Entry" },
{ 2, "Interface Identification" },
{ 0, NULL}
};

/* prototypes */
const char *icmp_tstamp_print(u_int);

/* print the milliseconds since midnight UTC */
const char *
icmp_tstamp_print(u_int tstamp)
{
u_int msec,sec,min,hrs;

static char buf[64];

msec = tstamp % 1000;
sec = tstamp / 1000;
min = sec / 60; sec -= min * 60;
hrs = min / 60; min -= hrs * 60;
snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
return buf;
}

UNALIGNED_OK
void
icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
int fragmented)
{
char *cp;
const struct icmp *dp;
uint8_t icmp_type, icmp_code;
const struct icmp_ext_t *ext_dp;
const struct ip *ip;
const char *str;
const struct ip *oip;
uint8_t ip_proto;
const struct udphdr *ouh;
const uint8_t *obj_tptr;
uint32_t raw_label;
const struct icmp_multipart_ext_object_header_t *icmp_multipart_ext_object_header;
u_int hlen, mtu, obj_tlen, obj_class_num, obj_ctype;
uint16_t dport;
char buf[MAXHOSTNAMELEN + 100];
struct cksum_vec vec[1];

ndo->ndo_protocol = "icmp";
dp = (const struct icmp *)bp;
ext_dp = (const struct icmp_ext_t *)bp;
ip = (const struct ip *)bp2;
str = buf;

icmp_type = GET_U_1(dp->icmp_type);
icmp_code = GET_U_1(dp->icmp_code);
switch (icmp_type) {

case ICMP_ECHO:
case ICMP_ECHOREPLY:
(void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
icmp_type == ICMP_ECHO ?
"request" : "reply",
GET_BE_U_2(dp->icmp_id),
GET_BE_U_2(dp->icmp_seq));
break;

case ICMP_UNREACH:
switch (icmp_code) {

case ICMP_UNREACH_NET:
(void)snprintf(buf, sizeof(buf),
"net %s unreachable",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_HOST:
(void)snprintf(buf, sizeof(buf),
"host %s unreachable",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_PROTOCOL:
(void)snprintf(buf, sizeof(buf),
"%s protocol %u unreachable",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
GET_U_1(dp->icmp_ip.ip_p));
break;

case ICMP_UNREACH_PORT:
ND_TCHECK_1(dp->icmp_ip.ip_p);
oip = &dp->icmp_ip;
hlen = IP_HL(oip) * 4;
ouh = (const struct udphdr *)(((const u_char *)oip) + hlen);
dport = GET_BE_U_2(ouh->uh_dport);
ip_proto = GET_U_1(oip->ip_p);
switch (ip_proto) {

case IPPROTO_TCP:
(void)snprintf(buf, sizeof(buf),
"%s tcp port %s unreachable",
GET_IPADDR_STRING(oip->ip_dst),
tcpport_string(ndo, dport));
break;

case IPPROTO_UDP:
(void)snprintf(buf, sizeof(buf),
"%s udp port %s unreachable",
GET_IPADDR_STRING(oip->ip_dst),
udpport_string(ndo, dport));
break;

default:
(void)snprintf(buf, sizeof(buf),
"%s protocol %u port %u unreachable",
GET_IPADDR_STRING(oip->ip_dst),
ip_proto, dport);
break;
}
break;

case ICMP_UNREACH_NEEDFRAG:
{
const struct mtu_discovery *mp;
mp = (const struct mtu_discovery *)(const u_char *)&dp->icmp_void;
mtu = GET_BE_U_2(mp->nexthopmtu);
if (mtu) {
(void)snprintf(buf, sizeof(buf),
"%s unreachable - need to frag (mtu %u)",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst), mtu);
} else {
(void)snprintf(buf, sizeof(buf),
"%s unreachable - need to frag",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
}
}
break;

case ICMP_UNREACH_SRCFAIL:
(void)snprintf(buf, sizeof(buf),
"%s unreachable - source route failed",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_NET_UNKNOWN:
(void)snprintf(buf, sizeof(buf),
"net %s unreachable - unknown",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_HOST_UNKNOWN:
(void)snprintf(buf, sizeof(buf),
"host %s unreachable - unknown",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_ISOLATED:
(void)snprintf(buf, sizeof(buf),
"%s unreachable - source host isolated",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_NET_PROHIB:
(void)snprintf(buf, sizeof(buf),
"net %s unreachable - admin prohibited",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_HOST_PROHIB:
(void)snprintf(buf, sizeof(buf),
"host %s unreachable - admin prohibited",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_TOSNET:
(void)snprintf(buf, sizeof(buf),
"net %s unreachable - tos prohibited",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_TOSHOST:
(void)snprintf(buf, sizeof(buf),
"host %s unreachable - tos prohibited",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_FILTER_PROHIB:
(void)snprintf(buf, sizeof(buf),
"host %s unreachable - admin prohibited filter",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_HOST_PRECEDENCE:
(void)snprintf(buf, sizeof(buf),
"host %s unreachable - host precedence violation",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

case ICMP_UNREACH_PRECEDENCE_CUTOFF:
(void)snprintf(buf, sizeof(buf),
"host %s unreachable - precedence cutoff",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst));
break;

default:
(void)snprintf(buf, sizeof(buf),
"%s unreachable - #%u",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
icmp_code);
break;
}
break;

case ICMP_REDIRECT:
switch (icmp_code) {

case ICMP_REDIRECT_NET:
(void)snprintf(buf, sizeof(buf),
"redirect %s to net %s",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
GET_IPADDR_STRING(dp->icmp_gwaddr));
break;

case ICMP_REDIRECT_HOST:
(void)snprintf(buf, sizeof(buf),
"redirect %s to host %s",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
GET_IPADDR_STRING(dp->icmp_gwaddr));
break;

case ICMP_REDIRECT_TOSNET:
(void)snprintf(buf, sizeof(buf),
"redirect-tos %s to net %s",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
GET_IPADDR_STRING(dp->icmp_gwaddr));
break;

case ICMP_REDIRECT_TOSHOST:
(void)snprintf(buf, sizeof(buf),
"redirect-tos %s to host %s",
GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
GET_IPADDR_STRING(dp->icmp_gwaddr));
break;

default:
(void)snprintf(buf, sizeof(buf),
"redirect-#%u %s to %s", icmp_code,
GET_IPADDR_STRING(dp->icmp_ip.ip_dst),
GET_IPADDR_STRING(dp->icmp_gwaddr));
break;
}
break;

case ICMP_ROUTERADVERT:
{
const struct ih_rdiscovery *ihp;
const struct id_rdiscovery *idp;
u_int lifetime, num, size;

(void)snprintf(buf, sizeof(buf), "router advertisement");
cp = buf + strlen(buf);

ihp = (const struct ih_rdiscovery *)&dp->icmp_void;
ND_TCHECK_SIZE(ihp);
(void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
cp = buf + strlen(buf);
lifetime = GET_BE_U_2(ihp->ird_lifetime);
if (lifetime < 60) {
(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
lifetime);
} else if (lifetime < 60 * 60) {
(void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
lifetime / 60, lifetime % 60);
} else {
(void)snprintf(cp, sizeof(buf) - (cp - buf),
"%u:%02u:%02u",
lifetime / 3600,
(lifetime % 3600) / 60,
lifetime % 60);
}
cp = buf + strlen(buf);

num = GET_U_1(ihp->ird_addrnum);
(void)snprintf(cp, sizeof(buf) - (cp - buf), " %u:", num);
cp = buf + strlen(buf);

size = GET_U_1(ihp->ird_addrsiz);
if (size != 2) {
(void)snprintf(cp, sizeof(buf) - (cp - buf),
" [size %u]", size);
break;
}
idp = (const struct id_rdiscovery *)&dp->icmp_data;
while (num > 0) {
ND_TCHECK_SIZE(idp);
(void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
GET_IPADDR_STRING(idp->ird_addr),
GET_BE_U_4(idp->ird_pref));
cp = buf + strlen(buf);
++idp;
num--;
}
}
break;

case ICMP_TIMXCEED:
ND_TCHECK_4(dp->icmp_ip.ip_dst);
switch (icmp_code) {

case ICMP_TIMXCEED_INTRANS:
str = "time exceeded in-transit";
break;

case ICMP_TIMXCEED_REASS:
str = "ip reassembly time exceeded";
break;

default:
(void)snprintf(buf, sizeof(buf), "time exceeded-#%u",
icmp_code);
break;
}
break;

case ICMP_PARAMPROB:
if (icmp_code)
(void)snprintf(buf, sizeof(buf),
"parameter problem - code %u", icmp_code);
else {
(void)snprintf(buf, sizeof(buf),
"parameter problem - octet %u",
GET_U_1(dp->icmp_pptr));
}
break;

case ICMP_MASKREPLY:
(void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
GET_BE_U_4(dp->icmp_mask));
break;

case ICMP_TSTAMP:
(void)snprintf(buf, sizeof(buf),
"time stamp query id %u seq %u",
GET_BE_U_2(dp->icmp_id),
GET_BE_U_2(dp->icmp_seq));
break;

case ICMP_TSTAMPREPLY:
ND_TCHECK_4(dp->icmp_ttime);
(void)snprintf(buf, sizeof(buf),
"time stamp reply id %u seq %u: org %s",
GET_BE_U_2(dp->icmp_id),
GET_BE_U_2(dp->icmp_seq),
icmp_tstamp_print(GET_BE_U_4(dp->icmp_otime)));

(void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
icmp_tstamp_print(GET_BE_U_4(dp->icmp_rtime)));
(void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
icmp_tstamp_print(GET_BE_U_4(dp->icmp_ttime)));
break;

default:
str = tok2str(icmp2str, "type-#%u", icmp_type);
break;
}
ND_PRINT("ICMP %s, length %u", str, plen);
if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
if (ND_TTEST_LEN(bp, plen)) {
uint16_t sum;

vec[0].ptr = (const uint8_t *)(const void *)dp;
vec[0].len = plen;
sum = in_cksum(vec, 1);
if (sum != 0) {
uint16_t icmp_sum = GET_BE_U_2(dp->icmp_cksum);
ND_PRINT(" (wrong icmp cksum %x (->%x)!)",
icmp_sum,
in_cksum_shouldbe(icmp_sum, sum));
}
}
}

/*
* print the remnants of the IP packet.
* save the snaplength as this may get overridden in the IP printer.
*/
if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(icmp_type)) {
const u_char *snapend_save;

bp += 8;
ND_PRINT("\n\t");
ip = (const struct ip *)bp;
snapend_save = ndo->ndo_snapend;
/*
* Update the snapend because extensions (MPLS, ...) may be
* present after the IP packet. In this case the current
* (outer) packet's snapend is not what ip_print() needs to
* decode an IP packet nested in the middle of an ICMP payload.
*
* This prevents that, in ip_print(), for the nested IP packet,
* the remaining length < remaining caplen.
*/
ndo->ndo_snapend = ND_MIN(bp + GET_BE_U_2(ip->ip_len),
ndo->ndo_snapend);
ip_print(ndo, bp, GET_BE_U_2(ip->ip_len));
ndo->ndo_snapend = snapend_save;
}

/* ndo_protocol reassignment after ip_print() call */
ndo->ndo_protocol = "icmp";

/*
* Attempt to decode multi-part message extensions (rfc4884) only for some ICMP types.
*/
if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MULTIPART_EXT_TYPE(icmp_type)) {

ND_TCHECK_SIZE(ext_dp);

/*
* Check first if the multi-part extension header shows a non-zero length.
* If the length field is not set then silently verify the checksum
* to check if an extension header is present. This is expedient,
* however not all implementations set the length field proper.
*/
if (GET_U_1(ext_dp->icmp_length) == 0 &&
ND_TTEST_LEN(ext_dp->icmp_ext_version_res, plen - ICMP_EXTD_MINLEN)) {
vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
vec[0].len = plen - ICMP_EXTD_MINLEN;
if (in_cksum(vec, 1)) {
return;
}
}

ND_PRINT("\n\tICMP Multi-Part extension v%u",
ICMP_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));

/*
* Sanity checking of the header.
*/
if (ICMP_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
ICMP_EXT_VERSION) {
ND_PRINT(" packet not supported");
return;
}

hlen = plen - ICMP_EXTD_MINLEN;
if (ND_TTEST_LEN(ext_dp->icmp_ext_version_res, hlen)) {
vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
vec[0].len = hlen;
ND_PRINT(", checksum 0x%04x (%scorrect), length %u",
GET_BE_U_2(ext_dp->icmp_ext_checksum),
in_cksum(vec, 1) ? "in" : "",
hlen);
}

hlen -= 4; /* subtract common header size */
obj_tptr = (const uint8_t *)ext_dp->icmp_ext_data;

while (hlen > sizeof(struct icmp_multipart_ext_object_header_t)) {

icmp_multipart_ext_object_header = (const struct icmp_multipart_ext_object_header_t *)obj_tptr;
ND_TCHECK_SIZE(icmp_multipart_ext_object_header);
obj_tlen = GET_BE_U_2(icmp_multipart_ext_object_header->length);
obj_class_num = GET_U_1(icmp_multipart_ext_object_header->class_num);
obj_ctype = GET_U_1(icmp_multipart_ext_object_header->ctype);
obj_tptr += sizeof(struct icmp_multipart_ext_object_header_t);

ND_PRINT("\n\t %s Object (%u), Class-Type: %u, length %u",
tok2str(icmp_multipart_ext_obj_values,"unknown",obj_class_num),
obj_class_num,
obj_ctype,
obj_tlen);

hlen-=sizeof(struct icmp_multipart_ext_object_header_t); /* length field includes tlv header */

/* infinite loop protection */
if ((obj_class_num == 0) ||
(obj_tlen < sizeof(struct icmp_multipart_ext_object_header_t))) {
return;
}
obj_tlen-=sizeof(struct icmp_multipart_ext_object_header_t);

switch (obj_class_num) {
case MPLS_STACK_ENTRY_OBJECT_CLASS:
switch(obj_ctype) {
case 1:
raw_label = GET_BE_U_4(obj_tptr);
ND_PRINT("\n\t label %u, tc %u", MPLS_LABEL(raw_label), MPLS_TC(raw_label));
if (MPLS_STACK(raw_label))
ND_PRINT(", [S]");
ND_PRINT(", ttl %u", MPLS_TTL(raw_label));
break;
default:
print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
}
break;

default:
print_unknown_data(ndo, obj_tptr, "\n\t ", obj_tlen);
break;
}
if (hlen < obj_tlen)
break;
hlen -= obj_tlen;
obj_tptr += obj_tlen;
}
}

return;
trunc:
nd_print_trunc(ndo);
}