The Tcpdump Group git mirrors - tcpdump/blob - print-ip6.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <netdissect-stdinc.h>
  27
  28 #include <string.h>
  29
  30 #include "netdissect.h"
  31 #include "addrtoname.h"
  32 #include "extract.h"
  33
  34 #include "ip6.h"
  35 #include "ipproto.h"
  36
  37 /*
  38  * Compute a V6-style checksum by building a pseudoheader.
  39  */
  40 int
  41 nextproto6_cksum(const struct ip6_hdr *ip6, const uint8_t *data,
  42                  u_int len, u_int covlen, u_int next_proto)
  43 {
  44         struct {
  45                 struct in6_addr ph_src;
  46                 struct in6_addr ph_dst;
  47                 uint32_t       ph_len;
  48                 uint8_t        ph_zero[3];
  49                 uint8_t        ph_nxt;
  50         } ph;
  51         struct cksum_vec vec[2];
  52
  53         /* pseudo-header */
  54         memset(&ph, 0, sizeof(ph));
  55         UNALIGNED_MEMCPY(&ph.ph_src, &ip6->ip6_src, sizeof (struct in6_addr));
  56         UNALIGNED_MEMCPY(&ph.ph_dst, &ip6->ip6_dst, sizeof (struct in6_addr));
  57         ph.ph_len = htonl(len);
  58         ph.ph_nxt = next_proto;
  59
  60         vec[0].ptr = (const uint8_t *)(void *)&ph;
  61         vec[0].len = sizeof(ph);
  62         vec[1].ptr = data;
  63         vec[1].len = covlen;
  64
  65         return in_cksum(vec, 2);
  66 }
  67
  68 /*
  69  * print an IP6 datagram.
  70  */
  71 void
  72 ip6_print(netdissect_options *ndo, const u_char *bp, u_int length)
  73 {
  74         register const struct ip6_hdr *ip6;
  75         register int advance;
  76         u_int len;
  77         const u_char *ipend;
  78         register const u_char *cp;
  79         register u_int payload_len;
  80         int nh;
  81         int fragmented = 0;
  82         u_int flow;
  83
  84         ip6 = (const struct ip6_hdr *)bp;
  85
  86         ND_TCHECK(*ip6);
  87         if (length < sizeof (struct ip6_hdr)) {
  88                 ND_PRINT((ndo, "truncated-ip6 %u", length));
  89                 return;
  90         }
  91
  92         if (!ndo->ndo_eflag)
  93             ND_PRINT((ndo, "IP6 "));
  94
  95         if (IP6_VERSION(ip6) != 6) {
  96           ND_PRINT((ndo,"version error: %u != 6", IP6_VERSION(ip6)));
  97           return;
  98         }
  99
 100         payload_len = EXTRACT_16BITS(&ip6->ip6_plen);
 101         len = payload_len + sizeof(struct ip6_hdr);
 102         if (length < len)
 103                 ND_PRINT((ndo, "truncated-ip6 - %u bytes missing!",
 104                         len - length));
 105
 106         if (ndo->ndo_vflag) {
 107             flow = EXTRACT_32BITS(&ip6->ip6_flow);
 108             ND_PRINT((ndo, "("));
 109 #if 0
 110             /* rfc1883 */
 111             if (flow & 0x0f000000)
 112                 ND_PRINT((ndo, "pri 0x%02x, ", (flow & 0x0f000000) >> 24));
 113             if (flow & 0x00ffffff)
 114                 ND_PRINT((ndo, "flowlabel 0x%06x, ", flow & 0x00ffffff));
 115 #else
 116             /* RFC 2460 */
 117             if (flow & 0x0ff00000)
 118                 ND_PRINT((ndo, "class 0x%02x, ", (flow & 0x0ff00000) >> 20));
 119             if (flow & 0x000fffff)
 120                 ND_PRINT((ndo, "flowlabel 0x%05x, ", flow & 0x000fffff));
 121 #endif
 122
 123             ND_PRINT((ndo, "hlim %u, next-header %s (%u) payload length: %u) ",
 124                          ip6->ip6_hlim,
 125                          tok2str(ipproto_values,"unknown",ip6->ip6_nxt),
 126                          ip6->ip6_nxt,
 127                          payload_len));
 128         }
 129
 130         /*
 131          * Cut off the snapshot length to the end of the IP payload.
 132          */
 133         ipend = bp + len;
 134         if (ipend < ndo->ndo_snapend)
 135                 ndo->ndo_snapend = ipend;
 136
 137         cp = (const u_char *)ip6;
 138         advance = sizeof(struct ip6_hdr);
 139         nh = ip6->ip6_nxt;
 140         while (cp < ndo->ndo_snapend && advance > 0) {
 141                 cp += advance;
 142                 len -= advance;
 143
 144                 if (cp == (const u_char *)(ip6 + 1) &&
 145                     nh != IPPROTO_TCP && nh != IPPROTO_UDP &&
 146                     nh != IPPROTO_DCCP && nh != IPPROTO_SCTP) {
 147                         ND_PRINT((ndo, "%s > %s: ", ip6addr_string(ndo, &ip6->ip6_src),
 148                                      ip6addr_string(ndo, &ip6->ip6_dst)));
 149                 }
 150
 151                 switch (nh) {
 152                 case IPPROTO_HOPOPTS:
 153                         advance = hbhopt_print(ndo, cp);
 154                         nh = *cp;
 155                         break;
 156                 case IPPROTO_DSTOPTS:
 157                         advance = dstopt_print(ndo, cp);
 158                         nh = *cp;
 159                         break;
 160                 case IPPROTO_FRAGMENT:
 161                         advance = frag6_print(ndo, cp, (const u_char *)ip6);
 162                         if (ndo->ndo_snapend <= cp + advance)
 163                                 return;
 164                         nh = *cp;
 165                         fragmented = 1;
 166                         break;
 167
 168                 case IPPROTO_MOBILITY_OLD:
 169                 case IPPROTO_MOBILITY:
 170                         /*
 171                          * XXX - we don't use "advance"; the current
 172                          * "Mobility Support in IPv6" draft
 173                          * (draft-ietf-mobileip-ipv6-24) says that
 174                          * the next header field in a mobility header
 175                          * should be IPPROTO_NONE, but speaks of
 176                          * the possiblity of a future extension in
 177                          * which payload can be piggybacked atop a
 178                          * mobility header.
 179                          */
 180                         advance = mobility_print(ndo, cp, (const u_char *)ip6);
 181                         nh = *cp;
 182                         return;
 183                 case IPPROTO_ROUTING:
 184                         advance = rt6_print(ndo, cp, (const u_char *)ip6);
 185                         nh = *cp;
 186                         break;
 187                 case IPPROTO_SCTP:
 188                         sctp_print(ndo, cp, (const u_char *)ip6, len);
 189                         return;
 190                 case IPPROTO_DCCP:
 191                         dccp_print(ndo, cp, (const u_char *)ip6, len);
 192                         return;
 193                 case IPPROTO_TCP:
 194                         tcp_print(ndo, cp, len, (const u_char *)ip6, fragmented);
 195                         return;
 196                 case IPPROTO_UDP:
 197                         udp_print(ndo, cp, len, (const u_char *)ip6, fragmented);
 198                         return;
 199                 case IPPROTO_ICMPV6:
 200                         icmp6_print(ndo, cp, len, (const u_char *)ip6, fragmented);
 201                         return;
 202                 case IPPROTO_AH:
 203                         advance = ah_print(ndo, cp);
 204                         nh = *cp;
 205                         break;
 206                 case IPPROTO_ESP:
 207                     {
 208                         int enh, padlen;
 209                         advance = esp_print(ndo, cp, len, (const u_char *)ip6, &enh, &padlen);
 210                         nh = enh & 0xff;
 211                         len -= padlen;
 212                         break;
 213                     }
 214                 case IPPROTO_IPCOMP:
 215                     {
 216                         int enh;
 217                         advance = ipcomp_print(ndo, cp, &enh);
 218                         nh = enh & 0xff;
 219                         break;
 220                     }
 221
 222                 case IPPROTO_PIM:
 223                         pim_print(ndo, cp, len, (const u_char *)ip6);
 224                         return;
 225
 226                 case IPPROTO_OSPF:
 227                         ospf6_print(ndo, cp, len);
 228                         return;
 229
 230                 case IPPROTO_IPV6:
 231                         ip6_print(ndo, cp, len);
 232                         return;
 233
 234                 case IPPROTO_IPV4:
 235                         ip_print(ndo, cp, len);
 236                         return;
 237
 238                 case IPPROTO_PGM:
 239                         pgm_print(ndo, cp, len, (const u_char *)ip6);
 240                         return;
 241
 242                 case IPPROTO_GRE:
 243                         gre_print(ndo, cp, len);
 244                         return;
 245
 246                 case IPPROTO_RSVP:
 247                         rsvp_print(ndo, cp, len);
 248                         return;
 249
 250                 case IPPROTO_NONE:
 251                         ND_PRINT((ndo, "no next header"));
 252                         return;
 253
 254                 default:
 255                         ND_PRINT((ndo, "ip-proto-%d %d", nh, len));
 256                         return;
 257                 }
 258         }
 259
 260         return;
 261 trunc:
 262         ND_PRINT((ndo, "[|ip6]"));
 263 }