]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-icmp.c
NTP: Use tstr for truncation indicator.
[tcpdump] / print-icmp.c
index 38a9d7bd726560dd80eeaa0a23854dd77425d528..10772213e212f61075f5aadaaac02b001a2c845f 100644 (file)
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#ifndef lint
-static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-icmp.c,v 1.58 2001-01-28 09:53:18 itojun Exp $ (LBL)";
-#endif
+/* \summary: Internet Control Message Protocol (ICMP) printer */
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include <sys/param.h>
-#include <sys/time.h>
-#include <sys/socket.h>
-
-struct mbuf;
-struct rtentry;
-
-#include <netinet/in.h>
+#include <netdissect-stdinc.h>
 
 #include <stdio.h>
 #include <string.h>
-#include <netdb.h>             /* for MAXHOSTNAMELEN on some platforms */
 
-#include "interface.h"
+#include "netdissect.h"
 #include "addrtoname.h"
-#include "extract.h"                   /* must come after interface.h */
+#include "extract.h"
 
 #include "ip.h"
 #include "udp.h"
+#include "ipproto.h"
+#include "mpls.h"
 
 /*
  * Interface Control Message Protocol Definitions.
@@ -57,43 +48,35 @@ struct rtentry;
  * Structure of an icmp header.
  */
 struct icmp {
-       u_int8_t  icmp_type;            /* type of message, see below */
-       u_int8_t  icmp_code;            /* type sub code */
-       u_int16_t icmp_cksum;           /* ones complement cksum of struct */
+       uint8_t  icmp_type;             /* type of message, see below */
+       uint8_t  icmp_code;             /* type sub code */
+       uint16_t icmp_cksum;            /* ones complement cksum of struct */
        union {
-               u_int8_t ih_pptr;                       /* ICMP_PARAMPROB */
+               uint8_t ih_pptr;                        /* ICMP_PARAMPROB */
                struct in_addr ih_gwaddr;       /* ICMP_REDIRECT */
                struct ih_idseq {
-                       u_int16_t icd_id;
-                       u_int16_t icd_seq;
+                       uint16_t icd_id;
+                       uint16_t icd_seq;
                } ih_idseq;
-               u_int32_t ih_void;
-
-               /* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */
-               struct ih_pmtu {
-                       u_int16_t ipm_void;    
-                       u_int16_t ipm_nextmtu;
-               } ih_pmtu;
+               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
-#define        icmp_pmvoid     icmp_hun.ih_pmtu.ipm_void
-#define        icmp_nextmtu    icmp_hun.ih_pmtu.ipm_nextmtu
        union {
                struct id_ts {
-                       u_int32_t its_otime;
-                       u_int32_t its_rtime;
-                       u_int32_t its_ttime;
+                       uint32_t its_otime;
+                       uint32_t its_rtime;
+                       uint32_t its_ttime;
                } id_ts;
                struct id_ip  {
                        struct ip idi_ip;
                        /* options and then 64 bits of data */
                } id_ip;
-               u_int32_t id_mask;
-               u_int8_t id_data[1];
+               uint32_t id_mask;
+               uint8_t id_data[1];
        } icmp_dun;
 #define        icmp_otime      icmp_dun.id_ts.its_otime
 #define        icmp_rtime      icmp_dun.id_ts.its_rtime
@@ -103,6 +86,9 @@ struct icmp {
 #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
@@ -112,7 +98,8 @@ struct icmp {
  * ip header length.
  */
 #define        ICMP_MINLEN     8                               /* abs minimum */
-#define        ICMP_TSLEN      (8 + 3 * sizeof (u_int32_t))    /* timestamp */
+#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)
@@ -159,12 +146,14 @@ struct icmp {
 
 #define        ICMP_MAXTYPE            18
 
-#define        ICMP_INFOTYPE(type) \
-       ((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
-       (type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
-       (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
-       (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
-       (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
+#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 */
@@ -200,7 +189,7 @@ struct icmp {
 #endif
 
 /* Most of the icmp types */
-static struct tok icmp2str[] = {
+static const struct tok icmp2str[] = {
        { ICMP_ECHOREPLY,               "echo reply" },
        { ICMP_SOURCEQUENCH,            "source quench" },
        { ICMP_ECHO,                    "echo request" },
@@ -214,7 +203,7 @@ static struct tok icmp2str[] = {
 };
 
 /* Formats for most of the ICMP_UNREACH codes */
-static struct tok unreach2str[] = {
+static const struct tok unreach2str[] = {
        { ICMP_UNREACH_NET,             "net %s unreachable" },
        { ICMP_UNREACH_HOST,            "host %s unreachable" },
        { ICMP_UNREACH_SRCFAIL,
@@ -241,95 +230,178 @@ static struct tok unreach2str[] = {
 };
 
 /* Formats for the ICMP_REDIRECT codes */
-static struct tok type2str[] = {
+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 net %s" },
+       { ICMP_REDIRECT_TOSHOST,        "redirect-tos %s to host %s" },
        { 0,                            NULL }
 };
 
 /* rfc1191 */
 struct mtu_discovery {
-       u_int16_t unused;
-       u_int16_t nexthopmtu;
+       uint16_t unused;
+       uint16_t nexthopmtu;
 };
 
 /* rfc1256 */
 struct ih_rdiscovery {
-       u_int8_t ird_addrnum;
-       u_int8_t ird_addrsiz;
-       u_int16_t ird_lifetime;
+       uint8_t ird_addrnum;
+       uint8_t ird_addrsiz;
+       uint16_t ird_lifetime;
 };
 
 struct id_rdiscovery {
-       u_int32_t ird_addr;
-       u_int32_t ird_pref;
+       uint32_t ird_addr;
+       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 {
+    uint8_t icmp_type;
+    uint8_t icmp_code;
+    uint8_t icmp_checksum[2];
+    uint8_t icmp_reserved;
+    uint8_t icmp_length;
+    uint8_t icmp_reserved2[2];
+    uint8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
+    uint8_t icmp_ext_version_res[2];
+    uint8_t icmp_ext_checksum[2];
+    uint8_t icmp_ext_data[1];
 };
 
+struct icmp_mpls_ext_object_header_t {
+    uint8_t length[2];
+    uint8_t class_num;
+    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;
+    snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
+    return buf;
+}
+
 void
-icmp_print(register const u_char *bp, u_int plen, register const u_char *bp2)
+icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
+           int fragmented)
 {
-       register char *cp;
-       register const struct icmp *dp;
-       register const struct ip *ip;
-       register const char *str, *fmt;
-       register const struct ip *oip;
-       register const struct udphdr *ouh;
-       register u_int hlen, dport, mtu;
+       char *cp;
+       const struct icmp *dp;
+        const struct icmp_ext_t *ext_dp;
+       const struct ip *ip;
+       const char *str, *fmt;
+       const struct ip *oip;
+       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 = (struct icmp *)bp;
-       ip = (struct ip *)bp2;
+       dp = (const struct icmp *)bp;
+        ext_dp = (const struct icmp_ext_t *)bp;
+       ip = (const struct ip *)bp2;
        str = buf;
 
-#if 0
-       (void)printf("%s > %s: ",
-               ipaddr_string(&ip->ip_src),
-               ipaddr_string(&ip->ip_dst));
-#endif
-
-       TCHECK(dp->icmp_code);
+       ND_TCHECK(dp->icmp_code);
        switch (dp->icmp_type) {
 
+       case ICMP_ECHO:
+       case ICMP_ECHOREPLY:
+               ND_TCHECK(dp->icmp_seq);
+               (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
+                               dp->icmp_type == ICMP_ECHO ?
+                               "request" : "reply",
+                               EXTRACT_16BITS(&dp->icmp_id),
+                               EXTRACT_16BITS(&dp->icmp_seq));
+               break;
+
        case ICMP_UNREACH:
-               TCHECK(dp->icmp_ip.ip_dst);
+               ND_TCHECK(dp->icmp_ip.ip_dst);
                switch (dp->icmp_code) {
 
                case ICMP_UNREACH_PROTOCOL:
-                       TCHECK(dp->icmp_ip.ip_p);
+                       ND_TCHECK(dp->icmp_ip.ip_p);
                        (void)snprintf(buf, sizeof(buf),
                            "%s protocol %d unreachable",
-                           ipaddr_string(&dp->icmp_ip.ip_dst),
+                           ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
                            dp->icmp_ip.ip_p);
                        break;
 
                case ICMP_UNREACH_PORT:
-                       TCHECK(dp->icmp_ip.ip_p);
+                       ND_TCHECK(dp->icmp_ip.ip_p);
                        oip = &dp->icmp_ip;
                        hlen = IP_HL(oip) * 4;
-                       ouh = (struct udphdr *)(((u_char *)oip) + hlen);
-                       dport = ntohs(ouh->uh_dport);
+                       ouh = (const struct udphdr *)(((const u_char *)oip) + hlen);
+                       ND_TCHECK(ouh->uh_dport);
+                       dport = EXTRACT_16BITS(&ouh->uh_dport);
                        switch (oip->ip_p) {
 
                        case IPPROTO_TCP:
                                (void)snprintf(buf, sizeof(buf),
                                        "%s tcp port %s unreachable",
-                                       ipaddr_string(&oip->ip_dst),
-                                       tcpport_string(dport));
+                                       ipaddr_string(ndo, &oip->ip_dst),
+                                       tcpport_string(ndo, dport));
                                break;
 
                        case IPPROTO_UDP:
                                (void)snprintf(buf, sizeof(buf),
                                        "%s udp port %s unreachable",
-                                       ipaddr_string(&oip->ip_dst),
-                                       udpport_string(dport));
+                                       ipaddr_string(ndo, &oip->ip_dst),
+                                       udpport_string(ndo, dport));
                                break;
 
                        default:
                                (void)snprintf(buf, sizeof(buf),
                                        "%s protocol %d port %d unreachable",
-                                       ipaddr_string(&oip->ip_dst),
+                                       ipaddr_string(ndo, &oip->ip_dst),
                                        oip->ip_p, dport);
                                break;
                        }
@@ -338,16 +410,16 @@ icmp_print(register const u_char *bp, u_int plen, register const u_char *bp2)
                case ICMP_UNREACH_NEEDFRAG:
                    {
                        register const struct mtu_discovery *mp;
-                       mp = (struct mtu_discovery *)&dp->icmp_void;
+                       mp = (const struct mtu_discovery *)(const u_char *)&dp->icmp_void;
                        mtu = EXTRACT_16BITS(&mp->nexthopmtu);
                        if (mtu) {
                                (void)snprintf(buf, sizeof(buf),
                                    "%s unreachable - need to frag (mtu %d)",
-                                   ipaddr_string(&dp->icmp_ip.ip_dst), mtu);
+                                   ipaddr_string(ndo, &dp->icmp_ip.ip_dst), mtu);
                        } else {
                                (void)snprintf(buf, sizeof(buf),
                                    "%s unreachable - need to frag",
-                                   ipaddr_string(&dp->icmp_ip.ip_dst));
+                                   ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
                        }
                    }
                        break;
@@ -356,18 +428,18 @@ icmp_print(register const u_char *bp, u_int plen, register const u_char *bp2)
                        fmt = tok2str(unreach2str, "#%d %%s unreachable",
                            dp->icmp_code);
                        (void)snprintf(buf, sizeof(buf), fmt,
-                           ipaddr_string(&dp->icmp_ip.ip_dst));
+                           ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
                        break;
                }
                break;
 
        case ICMP_REDIRECT:
-               TCHECK(dp->icmp_ip.ip_dst);
+               ND_TCHECK(dp->icmp_ip.ip_dst);
                fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
                    dp->icmp_code);
                (void)snprintf(buf, sizeof(buf), fmt,
-                   ipaddr_string(&dp->icmp_ip.ip_dst),
-                   ipaddr_string(&dp->icmp_gwaddr));
+                   ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
+                   ipaddr_string(ndo, &dp->icmp_gwaddr));
                break;
 
        case ICMP_ROUTERADVERT:
@@ -379,8 +451,8 @@ icmp_print(register const u_char *bp, u_int plen, register const u_char *bp2)
                (void)snprintf(buf, sizeof(buf), "router advertisement");
                cp = buf + strlen(buf);
 
-               ihp = (struct ih_rdiscovery *)&dp->icmp_void;
-               TCHECK(*ihp);
+               ihp = (const struct ih_rdiscovery *)&dp->icmp_void;
+               ND_TCHECK(*ihp);
                (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
                cp = buf + strlen(buf);
                lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
@@ -409,11 +481,11 @@ icmp_print(register const u_char *bp, u_int plen, register const u_char *bp2)
                            " [size %d]", size);
                        break;
                }
-               idp = (struct id_rdiscovery *)&dp->icmp_data;
+               idp = (const struct id_rdiscovery *)&dp->icmp_data;
                while (num-- > 0) {
-                       TCHECK(*idp);
+                       ND_TCHECK(*idp);
                        (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
-                           ipaddr_string(&idp->ird_addr),
+                           ipaddr_string(ndo, &idp->ird_addr),
                            EXTRACT_32BITS(&idp->ird_pref));
                        cp = buf + strlen(buf);
                        ++idp;
@@ -422,7 +494,7 @@ icmp_print(register const u_char *bp, u_int plen, register const u_char *bp2)
                break;
 
        case ICMP_TIMXCEED:
-               TCHECK(dp->icmp_ip.ip_dst);
+               ND_TCHECK(dp->icmp_ip.ip_dst);
                switch (dp->icmp_code) {
 
                case ICMP_TIMXCEED_INTRANS:
@@ -445,56 +517,181 @@ icmp_print(register const u_char *bp, u_int plen, register const u_char *bp2)
                        (void)snprintf(buf, sizeof(buf),
                            "parameter problem - code %d", dp->icmp_code);
                else {
-                       TCHECK(dp->icmp_pptr);
+                       ND_TCHECK(dp->icmp_pptr);
                        (void)snprintf(buf, sizeof(buf),
                            "parameter problem - octet %d", dp->icmp_pptr);
                }
                break;
 
        case ICMP_MASKREPLY:
-               TCHECK(dp->icmp_mask);
+               ND_TCHECK(dp->icmp_mask);
                (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
-                   (unsigned)ntohl(dp->icmp_mask));
+                   EXTRACT_32BITS(&dp->icmp_mask));
                break;
 
        case ICMP_TSTAMP:
-               TCHECK(dp->icmp_seq);
+               ND_TCHECK(dp->icmp_seq);
                (void)snprintf(buf, sizeof(buf),
                    "time stamp query id %u seq %u",
-                   (unsigned)ntohs(dp->icmp_id),
-                   (unsigned)ntohs(dp->icmp_seq));
+                   EXTRACT_16BITS(&dp->icmp_id),
+                   EXTRACT_16BITS(&dp->icmp_seq));
                break;
 
        case ICMP_TSTAMPREPLY:
-               TCHECK(dp->icmp_ttime);
+               ND_TCHECK(dp->icmp_ttime);
                (void)snprintf(buf, sizeof(buf),
-                   "time stamp reply id %u seq %u : org 0x%lx recv 0x%lx xmit 0x%lx",
-                   (unsigned)ntohs(dp->icmp_id),
-                   (unsigned)ntohs(dp->icmp_seq),
-                   (unsigned long)ntohl(dp->icmp_otime),
-                   (unsigned long)ntohl(dp->icmp_rtime),
-                   (unsigned long)ntohl(dp->icmp_ttime));
-               break;
+                   "time stamp reply id %u seq %u: org %s",
+                               EXTRACT_16BITS(&dp->icmp_id),
+                               EXTRACT_16BITS(&dp->icmp_seq),
+                               icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));
+
+                (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
+                         icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
+                (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
+                         icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
+                break;
 
        default:
                str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
                break;
        }
-       (void)printf("icmp: %s", str);
-       if (vflag) {
-               if (TTEST2(*bp, plen)) {
-                       if (in_cksum((u_short*)dp, plen, 0))
-                               printf(" (wrong icmp csum)");
+       ND_PRINT((ndo, "ICMP %s, length %u", str, plen));
+       if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
+               uint16_t sum, icmp_sum;
+
+               if (ND_TTEST2(*bp, plen)) {
+                       vec[0].ptr = (const uint8_t *)(const void *)dp;
+                       vec[0].len = plen;
+                       sum = in_cksum(vec, 1);
+                       if (sum != 0) {
+                               icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
+                               ND_PRINT((ndo, " (wrong icmp cksum %x (->%x)!)",
+                                            icmp_sum,
+                                            in_cksum_shouldbe(icmp_sum, sum)));
+                       }
                }
        }
-       if (vflag > 1 && !ICMP_INFOTYPE(dp->icmp_type)) {
-               bp += 8;
-               (void)printf(" for ");
-               ip = (struct ip *)bp;
-               snaplen = snapend - bp;
-               ip_print(bp, ntohs(ip->ip_len));
-       }
+
+        /*
+         * 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(dp->icmp_type)) {
+               bp += 8;
+               ND_PRINT((ndo, "\n\t"));
+               ip = (const struct ip *)bp;
+                snapend_save = ndo->ndo_snapend;
+               ip_print(ndo, bp, EXTRACT_16BITS(&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(dp->icmp_type)) {
+
+            ND_TCHECK(*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 (!ext_dp->icmp_length) {
+                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((ndo, "\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((ndo, " packet not supported"));
+                return;
+            }
+
+            hlen = plen - ICMP_EXTD_MINLEN;
+            vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
+            vec[0].len = hlen;
+            ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
+                   EXTRACT_16BITS(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(*icmp_mpls_ext_object_header);
+                obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
+                obj_class_num = icmp_mpls_ext_object_header->class_num;
+                obj_ctype = icmp_mpls_ext_object_header->ctype;
+                obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);
+
+                ND_PRINT((ndo, "\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_TCHECK2(*obj_tptr, 4);
+                        raw_label = EXTRACT_32BITS(obj_tptr);
+                        ND_PRINT((ndo, "\n\t    label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)));
+                        if (MPLS_STACK(raw_label))
+                            ND_PRINT((ndo, ", [S]"));
+                        ND_PRINT((ndo, ", 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:
-       fputs("[|icmp]", stdout);
+       ND_PRINT((ndo, "[|icmp]"));
 }
+/*
+ * Local Variables:
+ * c-style: whitesmith
+ * c-basic-offset: 8
+ * End:
+ */