]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-ip.c
ICMPv6: print RFC8335 PROBE extended echo/reply messages
[tcpdump] / print-ip.c
index 2951875ee970c90f6b778887172671c48f3abc86..5edc62215e2751d4d5f4dfb65b517f6faaf191c0 100644 (file)
@@ -1,7 +1,5 @@
-/*     $NetBSD: print-ip.c,v 1.4 1995/04/24 13:27:43 cgd Exp $ */
-
 /*
- * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
+ * Copyright (c) 1988, 1989, 1990, 1991, 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
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#ifndef lint
-static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.68 1999-10-17 21:56:54 mcr Exp $ (LBL)";
-#endif
-
-#include <sys/param.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-
-#include <netinet/in.h>
-#include <netinet/in_systm.h>
-#include <netinet/ip.h>
-#include <netinet/udp.h>
-#include <netinet/tcp.h>
-
-#include <stdio.h>
-#ifdef __STDC__
-#include <stdlib.h>
-#endif
-#include <unistd.h>
-
-#include "interface.h"
+/* \summary: IP printer */
+
+#include <config.h>
+
+#include "netdissect-stdinc.h"
+
+#include "netdissect.h"
 #include "addrtoname.h"
+#include "extract.h"
 
-static void
-igmp_print(register const u_char *bp, register int len,
-          register const u_char *bp2)
-{
-       register const struct ip *ip;
-       register const u_char *ep;
+#include "ip.h"
+#include "ipproto.h"
 
-       ip = (const struct ip *)bp2;
-       ep = (const u_char *)snapend;
-        (void)printf("%s > %s: ",
-               ipaddr_string(&ip->ip_src),
-               ipaddr_string(&ip->ip_dst));
 
-       if (bp + 7 > ep) {
-               (void)printf("[|igmp]");
-               return;
-       }
-       switch (bp[0] & 0xf) {
-       case 1:
-               (void)printf("igmp query");
-               if (*(int *)&bp[4])
-                       (void)printf(" [gaddr %s]", ipaddr_string(&bp[4]));
-               if (len != 8)
-                       (void)printf(" [len %d]", len);
-               break;
-       case 2:
-               (void)printf("igmp report %s", ipaddr_string(&bp[4]));
-               if (len != 8)
-                       (void)printf(" [len %d]", len);
-               break;
-       case 3:
-               (void)printf("igmp dvmrp %s", ipaddr_string(&bp[4]));
-               if (len < 8)
-                       (void)printf(" [len %d]", len);
-               break;
-       default:
-               (void)printf("igmp-%d", bp[0] & 0xf);
-               break;
-       }
-       if ((bp[0] >> 4) != 1)
-               (void)printf(" [v%d]", bp[0] >> 4);
-       if (bp[1])
-               (void)printf(" [b1=0x%x]", bp[1]);
-}
+static const struct tok ip_option_values[] = {
+    { IPOPT_EOL, "EOL" },
+    { IPOPT_NOP, "NOP" },
+    { IPOPT_TS, "timestamp" },
+    { IPOPT_SECURITY, "security" },
+    { IPOPT_RR, "RR" },
+    { IPOPT_SSRR, "SSRR" },
+    { IPOPT_LSRR, "LSRR" },
+    { IPOPT_RA, "RA" },
+    { IPOPT_RFC1393, "traceroute" },
+    { 0, NULL }
+};
 
 /*
  * print the recorded route in an IP RR, LSRR or SSRR option.
  */
-static void
-ip_printroute(const char *type, register const u_char *cp, int length)
+static int
+ip_printroute(netdissect_options *ndo,
+              const u_char *cp, u_int length)
 {
-       int ptr = cp[2] - 1;
-       int len;
+       u_int ptr;
+       u_int len;
 
-       printf(" %s{", type);
+       if (length < 3) {
+               ND_PRINT(" [bad length %u]", length);
+               return (0);
+       }
        if ((length + 1) & 3)
-               printf(" [bad length %d]", length);
+               ND_PRINT(" [bad length %u]", length);
+       ptr = GET_U_1(cp + 2) - 1;
        if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
-               printf(" [bad ptr %d]", cp[2]);
+               ND_PRINT(" [bad ptr %u]", GET_U_1(cp + 2));
 
-       type = "";
        for (len = 3; len < length; len += 4) {
-               if (ptr == len)
-                       type = "#";
-#ifdef TCPDUMP_ALIGN
-               {
-               struct in_addr addr;
-               bcopy((char *)&cp[len], (char *)&addr, sizeof(addr));
-               printf("%s%s", type, ipaddr_string(&addr));
+               ND_TCHECK_4(cp + len);  /* Needed to print the IP addresses */
+               ND_PRINT(" %s", GET_IPADDR_STRING(cp + len));
+               if (ptr > len)
+                       ND_PRINT(",");
+       }
+       return (0);
+
+trunc:
+       return (-1);
+}
+
+/*
+ * If source-routing is present and valid, return the final destination.
+ * Otherwise, return IP destination.
+ *
+ * This is used for UDP and TCP pseudo-header in the checksum
+ * calculation.
+ */
+static uint32_t
+ip_finddst(netdissect_options *ndo,
+           const struct ip *ip)
+{
+       u_int length;
+       u_int len;
+       const u_char *cp;
+
+       cp = (const u_char *)(ip + 1);
+       length = IP_HL(ip) * 4;
+       if (length < sizeof(struct ip))
+               goto trunc;
+       length -= sizeof(struct ip);
+
+       for (; length != 0; cp += len, length -= len) {
+               int tt;
+
+               tt = GET_U_1(cp);
+               if (tt == IPOPT_EOL)
+                       break;
+               else if (tt == IPOPT_NOP)
+                       len = 1;
+               else {
+                       len = GET_U_1(cp + 1);
+                       if (len < 2)
+                               break;
+               }
+               if (length < len)
+                       goto trunc;
+               ND_TCHECK_LEN(cp, len);
+               switch (tt) {
+
+               case IPOPT_SSRR:
+               case IPOPT_LSRR:
+                       if (len < 7)
+                               break;
+                       return (GET_IPV4_TO_NETWORK_ORDER(cp + len - 4));
                }
-#else
-               printf("%s%s", type, ipaddr_string(&cp[len]));
-#endif
+       }
+trunc:
+       return (GET_IPV4_TO_NETWORK_ORDER(ip->ip_dst));
+}
+
+/*
+ * Compute a V4-style checksum by building a pseudoheader.
+ */
+uint16_t
+nextproto4_cksum(netdissect_options *ndo,
+                 const struct ip *ip, const uint8_t *data,
+                 u_int len, u_int covlen, uint8_t next_proto)
+{
+       struct phdr {
+               uint32_t src;
+               uint32_t dst;
+               uint8_t mbz;
+               uint8_t proto;
+               uint16_t len;
+       } ph;
+       struct cksum_vec vec[2];
+
+       /* pseudo-header.. */
+       ph.len = htons((uint16_t)len);
+       ph.mbz = 0;
+       ph.proto = next_proto;
+       ph.src = GET_IPV4_TO_NETWORK_ORDER(ip->ip_src);
+       if (IP_HL(ip) == 5)
+               ph.dst = GET_IPV4_TO_NETWORK_ORDER(ip->ip_dst);
+       else
+               ph.dst = ip_finddst(ndo, ip);
+
+       vec[0].ptr = (const uint8_t *)(void *)&ph;
+       vec[0].len = sizeof(ph);
+       vec[1].ptr = data;
+       vec[1].len = covlen;
+       return (in_cksum(vec, 2));
+}
+
+static int
+ip_printts(netdissect_options *ndo,
+           const u_char *cp, u_int length)
+{
+       u_int ptr;
+       u_int len;
+       u_int hoplen;
+       const char *type;
+
+       if (length < 4) {
+               ND_PRINT("[bad length %u]", length);
+               return (0);
+       }
+       ND_PRINT(" TS{");
+       hoplen = ((GET_U_1(cp + 3) & 0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
+       if ((length - 4) & (hoplen-1))
+               ND_PRINT("[bad length %u]", length);
+       ptr = GET_U_1(cp + 2) - 1;
+       len = 0;
+       if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
+               ND_PRINT("[bad ptr %u]", GET_U_1(cp + 2));
+       switch (GET_U_1(cp + 3)&0xF) {
+       case IPOPT_TS_TSONLY:
+               ND_PRINT("TSONLY");
+               break;
+       case IPOPT_TS_TSANDADDR:
+               ND_PRINT("TS+ADDR");
+               break;
+       case IPOPT_TS_PRESPEC:
+               ND_PRINT("PRESPEC");
+               break;
+       default:
+               ND_PRINT("[bad ts type %u]", GET_U_1(cp + 3)&0xF);
+               goto done;
+       }
+
+       type = " ";
+       for (len = 4; len < length; len += hoplen) {
+               if (ptr == len)
+                       type = " ^ ";
+               ND_TCHECK_LEN(cp + len, hoplen);
+               ND_PRINT("%s%u@%s", type, GET_BE_U_4(cp + len + hoplen - 4),
+                         hoplen!=8 ? "" : GET_IPADDR_STRING(cp + len));
                type = " ";
        }
-       printf("%s}", ptr == len? "#" : "");
+
+done:
+       ND_PRINT("%s", ptr == len ? " ^ " : "");
+
+       if (GET_U_1(cp + 3) >> 4)
+               ND_PRINT(" [%u hops not recorded]} ", GET_U_1(cp + 3)>>4);
+       else
+               ND_PRINT("}");
+       return (0);
+
+trunc:
+       return (-1);
 }
 
 /*
  * print IP options.
+   If truncated return -1, else 0.
  */
-static void
-ip_optprint(register const u_char *cp, int length)
+static int
+ip_optprint(netdissect_options *ndo,
+            const u_char *cp, u_int length)
 {
-       int len;
+       u_int option_len;
+       const char *sep = "";
 
-       for (; length > 0; cp += len, length -= len) {
-               int tt = *cp;
+       for (; length > 0; cp += option_len, length -= option_len) {
+               u_int option_code;
 
-               len = (tt == IPOPT_NOP || tt == IPOPT_EOL) ? 1 : cp[1];
-               if (&cp[1] >= snapend || cp + len > snapend) {
-                       printf("[|ip]");
-                       return;
-               }
-               switch (tt) {
+               ND_PRINT("%s", sep);
+               sep = ",";
 
-               case IPOPT_EOL:
-                       printf(" EOL");
-                       if (length > 1)
-                               printf("-%d", length - 1);
-                       return;
+               option_code = GET_U_1(cp);
 
-               case IPOPT_NOP:
-                       printf(" NOP");
-                       break;
+               ND_PRINT("%s",
+                         tok2str(ip_option_values,"unknown %u",option_code));
 
-               case IPOPT_TS:
-                       printf(" TS{%d}", len);
-                       break;
+               if (option_code == IPOPT_NOP ||
+                    option_code == IPOPT_EOL)
+                       option_len = 1;
 
-               case IPOPT_SECURITY:
-                       printf(" SECURITY{%d}", len);
-                       break;
+               else {
+                       option_len = GET_U_1(cp + 1);
+                       if (option_len < 2) {
+                               ND_PRINT(" [bad length %u]", option_len);
+                               return 0;
+                       }
+               }
+
+               if (option_len > length) {
+                       ND_PRINT(" [bad length %u]", option_len);
+                       return 0;
+               }
 
-               case IPOPT_RR:
-                       printf(" RR{%d}=", len);
-                       ip_printroute("RR", cp, len);
+               ND_TCHECK_LEN(cp, option_len);
+
+               switch (option_code) {
+               case IPOPT_EOL:
+                       return 0;
+
+               case IPOPT_TS:
+                       if (ip_printts(ndo, cp, option_len) == -1)
+                               goto trunc;
                        break;
 
+               case IPOPT_RR:       /* fall through */
                case IPOPT_SSRR:
-                       ip_printroute("SSRR", cp, len);
+               case IPOPT_LSRR:
+                       if (ip_printroute(ndo, cp, option_len) == -1)
+                               goto trunc;
                        break;
 
-               case IPOPT_LSRR:
-                       ip_printroute("LSRR", cp, len);
+               case IPOPT_RA:
+                       if (option_len < 4) {
+                               ND_PRINT(" [bad length %u]", option_len);
+                               break;
+                       }
+                       ND_TCHECK_1(cp + 3);
+                       if (GET_BE_U_2(cp + 2) != 0)
+                               ND_PRINT(" value %u", GET_BE_U_2(cp + 2));
                        break;
 
+               case IPOPT_NOP:       /* nothing to print - fall through */
+               case IPOPT_SECURITY:
                default:
-                       printf(" IPOPT-%d{%d}", cp[0], len);
                        break;
                }
        }
-}
-
-/*
- * compute an IP header checksum.
- * don't modifiy the packet.
- */
-static int
-in_cksum(const struct ip *ip)
-{
-       register const u_short *sp = (u_short *)ip;
-       register u_int32 sum = 0;
-       register int count;
+       return 0;
 
-       /*
-        * No need for endian conversions.
-        */
-       for (count = ip->ip_hl * 2; --count >= 0; )
-               sum += *sp++;
-       while (sum > 0xffff)
-               sum = (sum & 0xffff) + (sum >> 16);
-       sum = ~sum & 0xffff;
-
-       return (sum);
+trunc:
+       return -1;
 }
 
+#define IP_RES 0x8000
+
+static const struct tok ip_frag_values[] = {
+        { IP_MF,        "+" },
+        { IP_DF,        "DF" },
+       { IP_RES,       "rsvd" }, /* The RFC3514 evil ;-) bit */
+        { 0,            NULL }
+};
 
-void
-print_ipproto(u_int proto, const struct ip *ip,
-             const u_char *cp,  int len)
-{
-  switch (proto) {
-  case IPPROTO_TCP:
-    tcp_print(cp, len, (const u_char *)ip);
-    break;
-  case IPPROTO_UDP:
-    udp_print(cp, len, (const u_char *)ip);
-    break;
-  case IPPROTO_ICMP:
-    icmp_print(cp, (const u_char *)ip);
-    break;
-  case IPPROTO_ND:
-    (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
-                ipaddr_string(&ip->ip_dst));
-    (void)printf(" nd %d", len);
-    break;
-  case IPPROTO_EGP:
-    egp_print(cp, len, (const u_char *)ip);
-    break;
-#ifndef IPPROTO_OSPF
-#define IPPROTO_OSPF 89
-#endif
-  case IPPROTO_OSPF:
-    ospf_print(cp, len, (const u_char *)ip);
-    break;
-#ifndef IPPROTO_IGMP
-#define IPPROTO_IGMP 2
-#endif
-  case IPPROTO_IGMP:
-    igmp_print(cp, len, (const u_char *)ip);
-    break;
-#ifndef IPPROTO_ENCAP
-#define IPPROTO_ENCAP 4
-#endif
-  case IPPROTO_ENCAP:
-    /* ip-in-ip encapsulation */
-    if (vflag)
-      (void)printf("%s > %s: ",
-                  ipaddr_string(&ip->ip_src),
-                  ipaddr_string(&ip->ip_dst));
-    ip_print(cp, len);
-    if (! vflag) {
-      printf(" (encap)");
-      return;
-    }
-    break;
-
-#ifndef IPPROTO_ESP
-#define IPPROTO_ESP 50
-#endif
-  case IPPROTO_ESP:
-    esp_print(cp, len, (const u_char *)ip);
-    break;
-
-#ifndef IPPROTO_AH
-#define IPPROTO_AH  51
-#endif
-  case IPPROTO_AH:
-    ah_print(cp, len, (const u_char *)ip);
-    break;
-    
-  default:
-    (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
-                ipaddr_string(&ip->ip_dst));
-    (void)printf(" ip-proto-%d %d", proto, len);
-    break;
-  }
-}
 
 /*
  * print an IP datagram.
  */
 void
-ip_print(register const u_char *bp, register int length)
+ip_print(netdissect_options *ndo,
+        const u_char *bp,
+        const u_int length)
 {
-       register const struct ip *ip;
-       register int hlen;
-       register int len;
-       register int off;
-       register const u_char *cp;
-
+       const struct ip *ip;
+       u_int off;
+       u_int hlen;
+       u_int len;
+       struct cksum_vec vec[1];
+       uint8_t ip_tos, ip_ttl, ip_proto;
+       uint16_t sum, ip_sum;
+       const char *p_name;
+       int truncated = 0;
+       int presumed_tso = 0;
+
+       ndo->ndo_protocol = "ip";
        ip = (const struct ip *)bp;
-#ifdef TCPDUMP_ALIGN
-       /*
-        * The IP header is not word aligned, so copy into abuf.
-        * This will never happen with BPF.  It does happen raw packet
-        * dumps from -r.
-        */
-       if ((long)ip & (sizeof(long)-1)) {
-               static u_char *abuf;
-
-               if (abuf == 0)
-                       abuf = (u_char *)malloc(snaplen);
-               bcopy((char *)ip, (char *)abuf, min(length, snaplen));
-               snapend += abuf - (u_char *)ip;
-               packetp = abuf;
-               ip = (struct ip *)abuf;
+
+       if (!ndo->ndo_eflag) {
+               nd_print_protocol_caps(ndo);
+               ND_PRINT(" ");
        }
-#endif
-       if ((u_char *)(ip + 1) > snapend) {
-               printf("[|ip]");
-               return;
+
+       ND_ICHECK_ZU(length, <, sizeof (struct ip));
+       ND_ICHECKMSG_U("version", IP_V(ip), !=, 4);
+
+       hlen = IP_HL(ip) * 4;
+       ND_ICHECKMSG_ZU("header length", hlen, <, sizeof (struct ip));
+
+       len = GET_BE_U_2(ip->ip_len);
+       if (len > length) {
+               ND_PRINT("[total length %u > length %u]", len, length);
+               nd_print_invalid(ndo);
+               ND_PRINT(" ");
        }
-       if (length < sizeof (struct ip)) {
-               (void)printf("truncated-ip %d", length);
-               return;
+       if (len == 0) {
+               /* we guess that it is a TSO send */
+               len = length;
+               presumed_tso = 1;
+       } else
+               ND_ICHECKMSG_U("total length", len, <, hlen);
+
+       ND_TCHECK_SIZE(ip);
+       /*
+        * Cut off the snapshot length to the end of the IP payload.
+        */
+       if (!nd_push_snaplen(ndo, bp, len)) {
+               (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+                       "%s: can't push snaplen on buffer stack", __func__);
        }
-       hlen = ip->ip_hl * 4;
 
-       len = ntohs(ip->ip_len);
-       if (length < len)
-               (void)printf("truncated-ip - %d bytes missing!",
-                       len - length);
        len -= hlen;
 
-       /*
-        * If this is fragment zero, hand it to the next higher
-        * level protocol.
-        */
-       off = ntohs(ip->ip_off);
-       if ((off & 0x1fff) == 0) {
-               cp = (const u_char *)ip + hlen;
-               print_ipproto(ip->ip_p, ip, cp, len);
+       off = GET_BE_U_2(ip->ip_off);
+
+        ip_proto = GET_U_1(ip->ip_p);
+
+        if (ndo->ndo_vflag) {
+            ip_tos = GET_U_1(ip->ip_tos);
+            ND_PRINT("(tos 0x%x", ip_tos);
+            /* ECN bits */
+            switch (ip_tos & 0x03) {
+
+            case 0:
+                break;
+
+            case 1:
+                ND_PRINT(",ECT(1)");
+                break;
+
+            case 2:
+                ND_PRINT(",ECT(0)");
+                break;
+
+            case 3:
+                ND_PRINT(",CE");
+                break;
+            }
+
+            ip_ttl = GET_U_1(ip->ip_ttl);
+            if (ip_ttl >= 1)
+                ND_PRINT(", ttl %u", ip_ttl);
+
+           /*
+            * for the firewall guys, print id, offset.
+             * On all but the last stick a "+" in the flags portion.
+            * For unfragmented datagrams, note the don't fragment flag.
+            */
+           ND_PRINT(", id %u, offset %u, flags [%s], proto %s (%u)",
+                         GET_BE_U_2(ip->ip_id),
+                         (off & IP_OFFMASK) * 8,
+                         bittok2str(ip_frag_values, "none", off & (IP_RES|IP_DF|IP_MF)),
+                         tok2str(ipproto_values, "unknown", ip_proto),
+                         ip_proto);
+
+           if (presumed_tso)
+                ND_PRINT(", length %u [was 0, presumed TSO]", length);
+           else
+                ND_PRINT(", length %u", GET_BE_U_2(ip->ip_len));
+
+            if ((hlen - sizeof(struct ip)) > 0) {
+                ND_PRINT(", options (");
+                if (ip_optprint(ndo, (const u_char *)(ip + 1),
+                    hlen - sizeof(struct ip)) == -1) {
+                        ND_PRINT(" [truncated-option]");
+                       truncated = 1;
+                }
+                ND_PRINT(")");
+            }
+
+           if (!ndo->ndo_Kflag && (const u_char *)ip + hlen <= ndo->ndo_snapend) {
+               vec[0].ptr = (const uint8_t *)(const void *)ip;
+               vec[0].len = hlen;
+               sum = in_cksum(vec, 1);
+               if (sum != 0) {
+                   ip_sum = GET_BE_U_2(ip->ip_sum);
+                   ND_PRINT(", bad cksum %x (->%x)!", ip_sum,
+                            in_cksum_shouldbe(ip_sum, sum));
+               }
+           }
+
+           ND_PRINT(")\n    ");
+           if (truncated) {
+               ND_PRINT("%s > %s: ",
+                        GET_IPADDR_STRING(ip->ip_src),
+                        GET_IPADDR_STRING(ip->ip_dst));
+               nd_print_trunc(ndo);
+               nd_pop_packet_info(ndo);
+               return;
+           }
        }
+
        /*
-        * for fragmented datagrams, print id:size@offset.  On all
-        * but the last stick a "+".  For unfragmented datagrams, note
-        * the don't fragment flag.
+        * If this is fragment zero, hand it to the next higher
+        * level protocol.  Let them know whether there are more
+        * fragments.
         */
-       if (off & 0x3fff) {
+       if ((off & IP_OFFMASK) == 0) {
+               uint8_t nh = GET_U_1(ip->ip_p);
+
+               if (nh != IPPROTO_TCP && nh != IPPROTO_UDP &&
+                   nh != IPPROTO_SCTP && nh != IPPROTO_DCCP) {
+                       ND_PRINT("%s > %s: ",
+                                    GET_IPADDR_STRING(ip->ip_src),
+                                    GET_IPADDR_STRING(ip->ip_dst));
+               }
                /*
-                * if this isn't the first frag, we're missing the
-                * next level protocol header.  print the ip addr.
+                * Do a bounds check before calling ip_demux_print().
+                * At least the header data is required.
                 */
-               if (off & 0x1fff)
-                       (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
-                                     ipaddr_string(&ip->ip_dst));
-               (void)printf(" (frag %d:%d@%d%s)", ntohs(ip->ip_id), len,
-                       (off & 0x1fff) * 8,
-                       (off & IP_MF)? "+" : "");
-       } else if (off & IP_DF)
-               (void)printf(" (DF)");
-
-       if (ip->ip_tos)
-               (void)printf(" [tos 0x%x]", (int)ip->ip_tos);
-       if (ip->ip_ttl <= 1)
-               (void)printf(" [ttl %d]", (int)ip->ip_ttl);
-
-       if (vflag) {
-               int sum;
-               char *sep = "";
-
-               printf(" (");
-               if (ip->ip_ttl > 1) {
-                       (void)printf("%sttl %d", sep, (int)ip->ip_ttl);
-                       sep = ", ";
-               }
-               if ((off & 0x3fff) == 0) {
-                       (void)printf("%sid %d", sep, (int)ntohs(ip->ip_id));
-                       sep = ", ";
-               }
-               sum = in_cksum(ip);
-               if (sum != 0) {
-                       (void)printf("%sbad cksum %x!", sep,
-                                    ntohs(ip->ip_sum));
-                       sep = ", ";
+               if (!ND_TTEST_LEN((const u_char *)ip, hlen)) {
+                       ND_PRINT(" [remaining caplen(%u) < header length(%u)]",
+                                ND_BYTES_AVAILABLE_AFTER((const u_char *)ip),
+                                hlen);
+                       nd_trunc_longjmp(ndo);
                }
-               if ((hlen -= sizeof(struct ip)) > 0) {
-                       (void)printf("%soptlen=%d", sep, hlen);
-                       ip_optprint((u_char *)(ip + 1), hlen);
+               ip_demux_print(ndo, (const u_char *)ip + hlen, len, 4,
+                              off & IP_MF, GET_U_1(ip->ip_ttl), nh, bp);
+       } else {
+               /*
+                * Ultra quiet now means that all this stuff should be
+                * suppressed.
+                */
+               if (ndo->ndo_qflag > 1) {
+                       nd_pop_packet_info(ndo);
+                       return;
                }
-               printf(")");
+
+               /*
+                * This isn't the first frag, so we're missing the
+                * next level protocol header.  print the ip addr
+                * and the protocol.
+                */
+               ND_PRINT("%s > %s:", GET_IPADDR_STRING(ip->ip_src),
+                         GET_IPADDR_STRING(ip->ip_dst));
+               if (!ndo->ndo_nflag && (p_name = netdb_protoname(ip_proto)) != NULL)
+                       ND_PRINT(" %s", p_name);
+               else
+                       ND_PRINT(" ip-proto-%u", ip_proto);
+       }
+       nd_pop_packet_info(ndo);
+       return;
+
+trunc:
+       nd_print_trunc(ndo);
+       return;
+
+invalid:
+       nd_print_invalid(ndo);
+}
+
+void
+ipN_print(netdissect_options *ndo, const u_char *bp, u_int length)
+{
+       ndo->ndo_protocol = "ipn";
+       if (length < 1) {
+               ND_PRINT("truncated-ip %u", length);
+               return;
+       }
+
+       switch (GET_U_1(bp) & 0xF0) {
+       case 0x40:
+               ip_print(ndo, bp, length);
+               break;
+       case 0x60:
+               ip6_print(ndo, bp, length);
+               break;
+       default:
+               ND_PRINT("unknown ip %u", (GET_U_1(bp) & 0xF0) >> 4);
+               break;
        }
 }