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

   1 /* Copyright (c) 2015, bugyo
   2  * All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are met:
   6  * 1. Redistributions of source code must retain the above copyright notice,
   7  *    this list of conditions and the following disclaimer.
   8  * 2. Redistributions in binary form must reproduce the above copyright notice,
   9  *    this list of conditions and the following disclaimer in the documentation
  10  *    and/or other materials provided with the distribution.
  11  *
  12  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  13  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  14  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  15  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
  16  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  17  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  18  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  19  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  20  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  21  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  22  */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include "config.h"
  26 #endif
  27
  28 #include <netdissect-stdinc.h>
  29
  30 #include "netdissect.h"
  31 #include "extract.h"
  32
  33 static const char tstr[] = " [|NSH]";
  34 static const struct tok nsh_flags [] = {
  35     { 0x20, "O" },
  36     { 0x10, "C" },
  37     { 0, NULL }
  38 };
  39
  40 #define NSH_BASE_HDR_LEN 4
  41 #define NSH_SERVICE_PATH_HDR_LEN 4
  42 #define NSH_HDR_WORD_SIZE 4
  43
  44 /*
  45  * NSH, draft-ietf-sfc-nsh-01 Network Service Header
  46  */
  47
  48 void
  49 nsh_print(netdissect_options *ndo, const u_char *bp, u_int len)
  50 {
  51     int n, vn;
  52     uint8_t ver;
  53     uint8_t flags;
  54     uint8_t length;
  55     uint8_t md_type;
  56     uint8_t next_protocol;
  57     uint32_t service_path_id;
  58     uint8_t service_index;
  59     uint32_t ctx;
  60     uint16_t tlv_class;
  61     uint8_t tlv_type;
  62     uint8_t tlv_len;
  63     u_int next_len;
  64
  65     /* print Base Header and Service Path Header */
  66     if (len < NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN)
  67         goto trunc;
  68
  69     ND_TCHECK2(*bp, NSH_BASE_HDR_LEN + NSH_SERVICE_PATH_HDR_LEN);
  70
  71     ver = (uint8_t)(*bp >> 6);
  72     flags = *bp;
  73     bp += 1;
  74     length = *bp;
  75     bp += 1;
  76     md_type = *bp;
  77     bp += 1;
  78     next_protocol = *bp;
  79     bp += 1;
  80     service_path_id = EXTRACT_24BITS(bp);
  81     bp += 3;
  82     service_index = *bp;
  83     bp += 1;
  84
  85     ND_PRINT((ndo, "NSH, "));
  86     if (ndo->ndo_vflag > 1) {
  87         ND_PRINT((ndo, "ver %d, ", ver));
  88     }
  89     ND_PRINT((ndo, "flags [%s], ", bittok2str_nosep(nsh_flags, "none", flags)));
  90     if (ndo->ndo_vflag > 2) {
  91         ND_PRINT((ndo, "length %d, ", length));
  92         ND_PRINT((ndo, "md type 0x%x, ", md_type));
  93     }
  94     if (ndo->ndo_vflag > 1) {
  95         ND_PRINT((ndo, "next-protocol 0x%x, ", next_protocol));
  96     }
  97     ND_PRINT((ndo, "service-path-id 0x%06x, ", service_path_id));
  98     ND_PRINT((ndo, "service-index 0x%x", service_index));
  99
 100     /* print Context Headers */
 101     if (len < length * NSH_HDR_WORD_SIZE)
 102         goto trunc;
 103
 104     ND_TCHECK2(*bp, length * NSH_HDR_WORD_SIZE);
 105
 106     if (ndo->ndo_vflag > 2) {
 107         if (md_type == 0x01) {
 108             for (n = 0; n < length - 2; n++) {
 109                 ctx = EXTRACT_32BITS(bp);
 110                 bp += NSH_HDR_WORD_SIZE;
 111                 ND_PRINT((ndo, "\n        Context[%02d]: 0x%08x", n, ctx));
 112             }
 113         }
 114         else if (md_type == 0x02) {
 115             n = 0;
 116             while (n < length - 2) {
 117                 tlv_class = EXTRACT_16BITS(bp);
 118                 bp += 2;
 119                 tlv_type  = *bp;
 120                 bp += 1;
 121                 tlv_len   = *bp;
 122                 bp += 1;
 123
 124                 ND_PRINT((ndo, "\n        TLV Class %d, Type %d, Len %d",
 125                           tlv_class, tlv_type, tlv_len));
 126
 127                 n += 1;
 128
 129                 if (length - 2 < n + tlv_len) {
 130                     ND_PRINT((ndo, " ERROR: invalid-tlv-length"));
 131                     return;
 132                 }
 133
 134                 for (vn = 0; vn < tlv_len; vn++) {
 135                     ctx = EXTRACT_32BITS(bp);
 136                     bp += NSH_HDR_WORD_SIZE;
 137                     ND_PRINT((ndo, "\n            Value[%02d]: 0x%08x", vn, ctx));
 138                 }
 139                 n += tlv_len;
 140             }
 141         }
 142         else {
 143             ND_PRINT((ndo, "ERROR: unknown-next-protocol"));
 144             return;
 145         }
 146     }
 147     else {
 148         bp += (length - 2) * NSH_HDR_WORD_SIZE;
 149     }
 150     ND_PRINT((ndo, ndo->ndo_vflag ? "\n    " : ": "));
 151
 152     /* print Next Protocol */
 153     next_len = len - length * NSH_HDR_WORD_SIZE;
 154     switch (next_protocol) {
 155     case 0x1:
 156         ip_print(ndo, bp, next_len);
 157         break;
 158     case 0x2:
 159         ip6_print(ndo, bp, next_len);
 160         break;
 161     case 0x3:
 162         ether_print(ndo, bp, next_len, next_len, NULL, NULL);
 163         break;
 164     default:
 165         ND_PRINT((ndo, "ERROR: unknown-next-protocol"));
 166         return;
 167     }
 168
 169     return;
 170
 171 trunc:
 172     ND_PRINT((ndo, "%s", tstr));
 173 }
 174