The Tcpdump Group git mirrors - tcpdump/blob - print-rt6.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 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 /* \summary: IPv6 routing header printer */
  23
  24 #include <config.h>
  25
  26 #include "netdissect-stdinc.h"
  27
  28 #include "netdissect.h"
  29 #include "addrtoname.h"
  30 #include "extract.h"
  31
  32 #include "ip6.h"
  33
  34 static const struct tok srh_tlv_type[] = {
  35     { IPV6_SRH_TLV_PAD1, "Pad1"},
  36     { IPV6_SRH_TLV_PADN, "PadN"},
  37     { IPV6_SRH_TLV_HMAC, "HMAC"},
  38     { 0, NULL }
  39 };
  40
  41 static int
  42 srh_tlv_print(netdissect_options *ndo, const u_char *p, u_int bytes_left)
  43 {
  44         u_int tlv_type, tlv_len;
  45         while (bytes_left != 0) {
  46                 tlv_type = GET_U_1(p);
  47                 ND_PRINT(", TLV-type=%s(%u)",
  48                          tok2str(srh_tlv_type, "Unknown", tlv_type),
  49                          tlv_type);
  50                 ND_ICHECKMSG_U("remaining length", bytes_left, <, 1);
  51                 p += 1;
  52                 bytes_left -= 1;
  53                 if (bytes_left == 0)
  54                         break;
  55                 if (tlv_type == IPV6_SRH_TLV_PAD1)
  56                         continue;
  57
  58                 tlv_len = GET_U_1(p);
  59                 ND_PRINT(", TLV-len=%u", tlv_len);
  60                 ND_ICHECKMSG_U("remaining length", bytes_left, <, 1);
  61                 p += 1;
  62                 bytes_left -= 1;
  63
  64                 switch (tlv_type) {
  65                 case IPV6_SRH_TLV_PADN:
  66                         ND_ICHECKMSG_U("PadN length", tlv_len, >, 5); /* RFC 8754 */
  67                         ND_ICHECKMSG_U("remaining length", bytes_left, <, tlv_len);
  68                         p += tlv_len;
  69                         bytes_left -= tlv_len;
  70                         break;
  71                 case IPV6_SRH_TLV_HMAC:
  72                         ND_ICHECKMSG_U("remaining length", bytes_left, <, 6);
  73                         uint16_t reserved;
  74                         uint32_t key_id;
  75                         uint8_t hmac_byte;
  76                         reserved = GET_BE_U_2(p);
  77                         p += 2;
  78                         if (ndo->ndo_vflag)
  79                                 ND_PRINT(", D=%u", reserved >> 15);
  80                         if (ndo->ndo_vflag && (reserved & 0x7fff) != 0)
  81                                 ND_PRINT(", reserved MBZ %u", reserved & 0x7fff);
  82                         key_id = GET_BE_U_4(p);
  83                         p += 4;
  84                         if (ndo->ndo_vflag)
  85                                 ND_PRINT(", HMAC-key-ID=0x%02x", key_id);
  86                         bytes_left -= 6;
  87                         if (ndo->ndo_vflag)
  88                                 ND_PRINT(", HMAC=0x");
  89                         for (u_int i = 0; i < tlv_len; i++) {
  90                                 hmac_byte = GET_U_1(p);
  91                                 ND_ICHECKMSG_U("remaining length", bytes_left, <, 1);
  92                                 p += 1;
  93                                 bytes_left -= 1;
  94                                 if (ndo->ndo_vflag)
  95                                         ND_PRINT("%02x", hmac_byte);
  96                         }
  97                         break;
  98                 default:        /* Unknown type */
  99                         if (ndo->ndo_vflag)
 100                                 ND_PRINT(", TLV-value=0x");
 101                         ND_ICHECKMSG_U("remaining length", bytes_left, <, tlv_len);
 102                         uint8_t tlv_byte;
 103                         for (u_int i = 0; i < tlv_len; i++) {
 104                                 tlv_byte = GET_U_1(p);
 105                                 p += 1;
 106                                 bytes_left -= 1;
 107                                 if (ndo->ndo_vflag)
 108                                         ND_PRINT("%02x", tlv_byte);
 109                         }
 110                         break;
 111                 }
 112         }
 113         return 0;
 114
 115 invalid:
 116         return -1;
 117 }
 118
 119
 120 int
 121 rt6_print(netdissect_options *ndo, const u_char *bp, const u_char *bp2 _U_)
 122 {
 123         const struct ip6_rthdr *dp;
 124         const struct ip6_rthdr0 *dp0;
 125         const struct ip6_srh *srh;
 126         u_int i, len, type, seg_list_len, last_entry;
 127         int err;
 128         const u_char *p;
 129
 130         ndo->ndo_protocol = "rt6";
 131
 132         nd_print_protocol_caps(ndo);
 133         dp = (const struct ip6_rthdr *)bp;
 134
 135         len = GET_U_1(dp->ip6r_len);
 136         ND_PRINT(" (len=%u", len);      /*)*/
 137         type = GET_U_1(dp->ip6r_type);
 138         ND_PRINT(", type=%u", type);
 139         if (type == IPV6_RTHDR_TYPE_0)
 140                 ND_PRINT(" [Deprecated]");
 141         ND_PRINT(", segleft=%u", GET_U_1(dp->ip6r_segleft));
 142
 143         switch (type) {
 144         case IPV6_RTHDR_TYPE_0:
 145         case IPV6_RTHDR_TYPE_2:                 /* Mobile IPv6 ID-20 */
 146                 dp0 = (const struct ip6_rthdr0 *)dp;
 147
 148                 if (GET_BE_U_4(dp0->ip6r0_reserved) || ndo->ndo_vflag) {
 149                         ND_PRINT(", rsv=0x%0x",
 150                             GET_BE_U_4(dp0->ip6r0_reserved));
 151                 }
 152
 153                 if (len % 2 == 1) {
 154                         ND_PRINT(" [length %u]", len);
 155                         goto invalid;
 156                 }
 157                 len >>= 1;
 158                 p = (const u_char *) dp0->ip6r0_addr;
 159                 for (i = 0; i < len; i++) {
 160                         ND_PRINT(", [%u]%s", i, GET_IP6ADDR_STRING(p));
 161                         p += 16;
 162                 }
 163                 /*(*/
 164                 ND_PRINT(") ");
 165                 return((GET_U_1(dp0->ip6r0_len) + 1) << 3);
 166         case IPV6_RTHDR_TYPE_4:
 167                 srh = (const struct ip6_srh *)dp;
 168                 last_entry = GET_U_1(srh->srh_last_ent);
 169                 ND_PRINT(", last-entry=%u", last_entry);
 170
 171                 if (GET_U_1(srh->srh_flags) || ndo->ndo_vflag) {
 172                         ND_PRINT(", flags=0x%0x",
 173                                 GET_U_1(srh->srh_flags));
 174                 }
 175
 176                 ND_PRINT(", tag=%x", GET_BE_U_2(srh->srh_tag));
 177                 p  = (const u_char *) srh->srh_segments;
 178                 for (i = 0; i < last_entry + 1; i++) {
 179                         ND_PRINT(", [%u]%s", i, GET_IP6ADDR_STRING(p));
 180                         p += 16;
 181                 }
 182                 seg_list_len = (last_entry + 1) * 2;
 183                 if (seg_list_len < len) {
 184                         /* there is TLV */
 185                         u_int bytes_left;
 186                         bytes_left = (len - seg_list_len) * 8;
 187                         err = srh_tlv_print(ndo, p, bytes_left);
 188                         if (err)
 189                                 goto invalid;
 190                 }
 191
 192                 /*(*/
 193                 ND_PRINT(") ");
 194                 return((GET_U_1(srh->srh_len) + 1) << 3);
 195         default:
 196                 ND_PRINT(" (unknown type)");
 197                 goto invalid;
 198         }
 199
 200 invalid:
 201         nd_print_invalid(ndo);
 202         return -1;
 203 }