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aa9960a2c3
tcpdump/print-icmp.c
Francois-Xavier Le Bail aa9960a2c3 ICMP: Replace a 'struct in_addr' member type with a 'nd_ipv4' one 
In 'struct icmp'.
This avoid some 'undefined-behavior' warnings with clang and option
-fsanitize=undefined enabled.

Moreover:
Remove unneeded '&' when getting a pointer to a nd_ipv4 type.
Fix indentation.

The warnings were like:
print-icmp.c:355:2: runtime error: member access within misaligned address
0x61d00001eabe for type 'const struct icmp', which requires 4 byte alignment
0x61d00001eabe: note: pointer points here
 ef 01 02 03 08 00  90 e1 00 03 00 00 00 00  00 00 00 05 ed 60 ab cd  ab cd ab cd ab cd ab cd  ab cd
             ^
SUMMARY: AddressSanitizer: undefined-behavior print-icmp.c:355:2 in
2018-01-30 16:38:48 +01:00

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/*
* 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.
*/
/* \summary: Internet Control Message Protocol (ICMP) printer */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#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
};
#define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
#define ICMP_MPLS_EXT_VERSION 2
/*
* Lower bounds on packet lengths for various types.
* For the error advice packets must first insure that the
* packet is large enought 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_MPLS_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 }
};
/* Formats for most of the ICMP_UNREACH codes */
static const struct tok unreach2str[] = {
{ ICMP_UNREACH_NET, "net %s unreachable" },
{ ICMP_UNREACH_HOST, "host %s unreachable" },
{ ICMP_UNREACH_SRCFAIL,
"%s unreachable - source route failed" },
{ ICMP_UNREACH_NET_UNKNOWN, "net %s unreachable - unknown" },
{ ICMP_UNREACH_HOST_UNKNOWN, "host %s unreachable - unknown" },
{ ICMP_UNREACH_ISOLATED,
"%s unreachable - source host isolated" },
{ ICMP_UNREACH_NET_PROHIB,
"net %s unreachable - admin prohibited" },
{ ICMP_UNREACH_HOST_PROHIB,
"host %s unreachable - admin prohibited" },
{ ICMP_UNREACH_TOSNET,
"net %s unreachable - tos prohibited" },
{ ICMP_UNREACH_TOSHOST,
"host %s unreachable - tos prohibited" },
{ ICMP_UNREACH_FILTER_PROHIB,
"host %s unreachable - admin prohibited filter" },
{ ICMP_UNREACH_HOST_PRECEDENCE,
"host %s unreachable - host precedence violation" },
{ ICMP_UNREACH_PRECEDENCE_CUTOFF,
"host %s unreachable - precedence cutoff" },
{ 0, NULL }
};
/* Formats for the ICMP_REDIRECT codes */
static const struct tok type2str[] = {
{ ICMP_REDIRECT_NET, "redirect %s to net %s" },
{ ICMP_REDIRECT_HOST, "redirect %s to host %s" },
{ ICMP_REDIRECT_TOSNET, "redirect-tos %s to net %s" },
{ ICMP_REDIRECT_TOSHOST, "redirect-tos %s to host %s" },
{ 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;
};
/*
* draft-bonica-internet-icmp-08
*
* The Destination Unreachable, Time Exceeded
* and Parameter Problem messages are slighly changed as per
* the above draft. A new Length field gets added to give
* the caller an idea about the length of the piggypacked
* IP packet before the MPLS 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];
};
struct icmp_mpls_ext_object_header_t {
nd_uint16_t length;
nd_uint8_t class_num;
nd_uint8_t ctype;
};
static const struct tok icmp_mpls_ext_obj_values[] = {
{ 1, "MPLS Stack Entry" },
{ 2, "Extended Payload" },
{ 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;
nd_snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
return buf;
}
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, *fmt;
const struct ip *oip;
uint8_t ip_proto;
const struct udphdr *ouh;
const uint8_t *obj_tptr;
uint32_t raw_label;
const u_char *snapend_save;
const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
char buf[MAXHOSTNAMELEN + 100];
struct cksum_vec vec[1];
dp = (const struct icmp *)bp;
ext_dp = (const struct icmp_ext_t *)bp;
ip = (const struct ip *)bp2;
str = buf;
ND_TCHECK_1(dp->icmp_code);
icmp_type = EXTRACT_U_1(dp->icmp_type);
icmp_code = EXTRACT_U_1(dp->icmp_code);
switch (icmp_type) {
case ICMP_ECHO:
case ICMP_ECHOREPLY:
ND_TCHECK_2(dp->icmp_seq);
(void)nd_snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
icmp_type == ICMP_ECHO ?
"request" : "reply",
EXTRACT_BE_U_2(dp->icmp_id),
EXTRACT_BE_U_2(dp->icmp_seq));
break;
case ICMP_UNREACH:
ND_TCHECK_4(dp->icmp_ip.ip_dst);
switch (icmp_code) {
case ICMP_UNREACH_PROTOCOL:
ND_TCHECK_1(dp->icmp_ip.ip_p);
(void)nd_snprintf(buf, sizeof(buf),
"%s protocol %u unreachable",
ipaddr_string(ndo, dp->icmp_ip.ip_dst),
EXTRACT_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);
ND_TCHECK_2(ouh->uh_dport);
dport = EXTRACT_BE_U_2(ouh->uh_dport);
ip_proto = EXTRACT_U_1(oip->ip_p);
switch (ip_proto) {
case IPPROTO_TCP:
(void)nd_snprintf(buf, sizeof(buf),
"%s tcp port %s unreachable",
ipaddr_string(ndo, oip->ip_dst),
tcpport_string(ndo, dport));
break;
case IPPROTO_UDP:
(void)nd_snprintf(buf, sizeof(buf),
"%s udp port %s unreachable",
ipaddr_string(ndo, oip->ip_dst),
udpport_string(ndo, dport));
break;
default:
(void)nd_snprintf(buf, sizeof(buf),
"%s protocol %u port %u unreachable",
ipaddr_string(ndo, 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 = EXTRACT_BE_U_2(mp->nexthopmtu);
if (mtu) {
(void)nd_snprintf(buf, sizeof(buf),
"%s unreachable - need to frag (mtu %u)",
ipaddr_string(ndo, dp->icmp_ip.ip_dst), mtu);
} else {
(void)nd_snprintf(buf, sizeof(buf),
"%s unreachable - need to frag",
ipaddr_string(ndo, dp->icmp_ip.ip_dst));
}
}
break;
default:
fmt = tok2str(unreach2str, "#%u %%s unreachable",
icmp_code);
(void)nd_snprintf(buf, sizeof(buf), fmt,
ipaddr_string(ndo, dp->icmp_ip.ip_dst));
break;
}
break;
case ICMP_REDIRECT:
ND_TCHECK_4(dp->icmp_ip.ip_dst);
fmt = tok2str(type2str, "redirect-#%u %%s to net %%s",
icmp_code);
(void)nd_snprintf(buf, sizeof(buf), fmt,
ipaddr_string(ndo, dp->icmp_ip.ip_dst),
ipaddr_string(ndo, dp->icmp_gwaddr));
break;
case ICMP_ROUTERADVERT:
{
const struct ih_rdiscovery *ihp;
const struct id_rdiscovery *idp;
u_int lifetime, num, size;
(void)nd_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 = EXTRACT_BE_U_2(ihp->ird_lifetime);
if (lifetime < 60) {
(void)nd_snprintf(cp, sizeof(buf) - (cp - buf), "%u",
lifetime);
} else if (lifetime < 60 * 60) {
(void)nd_snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
lifetime / 60, lifetime % 60);
} else {
(void)nd_snprintf(cp, sizeof(buf) - (cp - buf),
"%u:%02u:%02u",
lifetime / 3600,
(lifetime % 3600) / 60,
lifetime % 60);
}
cp = buf + strlen(buf);
num = EXTRACT_U_1(ihp->ird_addrnum);
(void)nd_snprintf(cp, sizeof(buf) - (cp - buf), " %u:", num);
cp = buf + strlen(buf);
size = EXTRACT_U_1(ihp->ird_addrsiz);
if (size != 2) {
(void)nd_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)nd_snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
ipaddr_string(ndo, idp->ird_addr),
EXTRACT_BE_U_4(idp->ird_pref));
cp = buf + strlen(buf);
++idp;
}
}
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)nd_snprintf(buf, sizeof(buf), "time exceeded-#%u",
icmp_code);
break;
}
break;
case ICMP_PARAMPROB:
if (icmp_code)
(void)nd_snprintf(buf, sizeof(buf),
"parameter problem - code %u", icmp_code);
else {
ND_TCHECK_1(dp->icmp_pptr);
(void)nd_snprintf(buf, sizeof(buf),
"parameter problem - octet %u", EXTRACT_U_1(dp->icmp_pptr));
}
break;
case ICMP_MASKREPLY:
ND_TCHECK_4(dp->icmp_mask);
(void)nd_snprintf(buf, sizeof(buf), "address mask is 0x%08x",
EXTRACT_BE_U_4(dp->icmp_mask));
break;
case ICMP_TSTAMP:
ND_TCHECK_2(dp->icmp_seq);
(void)nd_snprintf(buf, sizeof(buf),
"time stamp query id %u seq %u",
EXTRACT_BE_U_2(dp->icmp_id),
EXTRACT_BE_U_2(dp->icmp_seq));
break;
case ICMP_TSTAMPREPLY:
ND_TCHECK_4(dp->icmp_ttime);
(void)nd_snprintf(buf, sizeof(buf),
"time stamp reply id %u seq %u: org %s",
EXTRACT_BE_U_2(dp->icmp_id),
EXTRACT_BE_U_2(dp->icmp_seq),
icmp_tstamp_print(EXTRACT_BE_U_4(dp->icmp_otime)));
(void)nd_snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
icmp_tstamp_print(EXTRACT_BE_U_4(dp->icmp_rtime)));
(void)nd_snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
icmp_tstamp_print(EXTRACT_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 = EXTRACT_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 overidden in the IP printer.
*/
if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(icmp_type)) {
bp += 8;
ND_PRINT("\n\t");
ip = (const struct ip *)bp;
snapend_save = ndo->ndo_snapend;
ND_TCHECK_2(ip->ip_len);
ip_print(ndo, bp, EXTRACT_BE_U_2(ip->ip_len));
ndo->ndo_snapend = snapend_save;
}
/*
* Attempt to decode the MPLS extensions only for some ICMP types.
*/
if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(icmp_type)) {
ND_TCHECK_SIZE(ext_dp);
/*
* Check first if the mpls 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 (EXTRACT_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\tMPLS extension v%u",
ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)));
/*
* Sanity checking of the header.
*/
if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
ICMP_MPLS_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",
EXTRACT_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_mpls_ext_object_header_t)) {
icmp_mpls_ext_object_header = (const struct icmp_mpls_ext_object_header_t *)obj_tptr;
ND_TCHECK_SIZE(icmp_mpls_ext_object_header);
obj_tlen = EXTRACT_BE_U_2(icmp_mpls_ext_object_header->length);
obj_class_num = EXTRACT_U_1(icmp_mpls_ext_object_header->class_num);
obj_ctype = EXTRACT_U_1(icmp_mpls_ext_object_header->ctype);
obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
ND_PRINT("\n\t %s Object (%u), Class-Type: %u, length %u",
tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
obj_class_num,
obj_ctype,
obj_tlen);
hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */
/* infinite loop protection */
if ((obj_class_num == 0) ||
(obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
return;
}
obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);
switch (obj_class_num) {
case 1:
switch(obj_ctype) {
case 1:
ND_TCHECK_4(obj_tptr);
raw_label = EXTRACT_BE_U_4(obj_tptr);
ND_PRINT("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(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;
/*
* FIXME those are the defined objects that lack a decoder
* you are welcome to contribute code ;-)
*/
case 2:
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("[|icmp]");
}
/*
* Local Variables:
* c-style: whitesmith
* c-basic-offset: 8
* End:
*/
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