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

   1 /*
   2  * Copyright (c) 2013, Petar Alilovic,
   3  * Faculty of Electrical Engineering and Computing, University of Zagreb
   4  * All rights reserved
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are met:
   8  *
   9  * * Redistributions of source code must retain the above copyright notice,
  10  *       this list of conditions and the following disclaimer.
  11  * * Redistributions in binary form must reproduce the above copyright
  12  *       notice, this list of conditions and the following disclaimer in the
  13  *       documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
  16  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
  19  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  20  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  22  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  25  * DAMAGE.
  26  */
  27
  28 /* \summary: DLT_NFLOG printer */
  29
  30 #ifdef HAVE_CONFIG_H
  31 #include <config.h>
  32 #endif
  33
  34 #include "netdissect-stdinc.h"
  35
  36 #include "netdissect.h"
  37 static const char tstr[] = " [|nflog]";
  38
  39 #if defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H)
  40 #include <pcap/nflog.h>
  41
  42 static const struct tok nflog_values[] = {
  43         { AF_INET,              "IPv4" },
  44 #ifdef AF_INET6
  45         { AF_INET6,             "IPv6" },
  46 #endif /*AF_INET6*/
  47         { 0,                    NULL }
  48 };
  49
  50 static void
  51 nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
  52 {
  53         ND_PRINT("version %d, resource ID %d", hdr->nflog_version, ntohs(hdr->nflog_rid));
  54
  55         if (!ndo->ndo_qflag) {
  56                 ND_PRINT(", family %s (%d)",
  57                          tok2str(nflog_values, "Unknown",
  58                                  hdr->nflog_family),
  59                          hdr->nflog_family);
  60                 } else {
  61                 ND_PRINT(", %s",
  62                          tok2str(nflog_values,
  63                                  "Unknown NFLOG (0x%02x)",
  64                          hdr->nflog_family));
  65                 }
  66
  67         ND_PRINT(", length %u: ", length);
  68 }
  69
  70 u_int
  71 nflog_if_print(netdissect_options *ndo,
  72                            const struct pcap_pkthdr *h, const u_char *p)
  73 {
  74         const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
  75         uint16_t size;
  76         uint16_t h_size = sizeof(nflog_hdr_t);
  77         u_int caplen = h->caplen;
  78         u_int length = h->len;
  79
  80         ndo->ndo_protocol = "nflog_if";
  81         if (caplen < sizeof(nflog_hdr_t) || length < sizeof(nflog_hdr_t))
  82                 goto trunc;
  83
  84         ND_TCHECK_SIZE(hdr);
  85         if (hdr->nflog_version != 0) {
  86                 ND_PRINT("version %u (unknown)", hdr->nflog_version);
  87                 return h_size;
  88         }
  89
  90         if (ndo->ndo_eflag)
  91                 nflog_hdr_print(ndo, hdr, length);
  92
  93         p += sizeof(nflog_hdr_t);
  94         length -= sizeof(nflog_hdr_t);
  95         caplen -= sizeof(nflog_hdr_t);
  96
  97         while (length > 0) {
  98                 const nflog_tlv_t *tlv;
  99
 100                 /* We have some data.  Do we have enough for the TLV header? */
 101                 if (caplen < sizeof(nflog_tlv_t) || length < sizeof(nflog_tlv_t))
 102                         goto trunc;     /* No. */
 103
 104                 tlv = (const nflog_tlv_t *) p;
 105                 ND_TCHECK_SIZE(tlv);
 106                 size = tlv->tlv_length;
 107                 if (size % 4 != 0)
 108                         size += 4 - size % 4;
 109
 110                 /* Is the TLV's length less than the minimum? */
 111                 if (size < sizeof(nflog_tlv_t))
 112                         goto trunc;     /* Yes. Give up now. */
 113
 114                 /* Do we have enough data for the full TLV? */
 115                 if (caplen < size || length < size)
 116                         goto trunc;     /* No. */
 117
 118                 if (tlv->tlv_type == NFULA_PAYLOAD) {
 119                         /*
 120                          * This TLV's data is the packet payload.
 121                          * Skip past the TLV header, and break out
 122                          * of the loop so we print the packet data.
 123                          */
 124                         p += sizeof(nflog_tlv_t);
 125                         h_size += sizeof(nflog_tlv_t);
 126                         length -= sizeof(nflog_tlv_t);
 127                         caplen -= sizeof(nflog_tlv_t);
 128                         break;
 129                 }
 130
 131                 p += size;
 132                 h_size += size;
 133                 length -= size;
 134                 caplen -= size;
 135         }
 136
 137         switch (hdr->nflog_family) {
 138
 139         case AF_INET:
 140                 ip_print(ndo, p, length);
 141                 break;
 142
 143 #ifdef AF_INET6
 144         case AF_INET6:
 145                 ip6_print(ndo, p, length);
 146                 break;
 147 #endif /* AF_INET6 */
 148
 149         default:
 150                 if (!ndo->ndo_eflag)
 151                         nflog_hdr_print(ndo, hdr,
 152                                 length + sizeof(nflog_hdr_t));
 153
 154                 if (!ndo->ndo_suppress_default_print)
 155                         ND_DEFAULTPRINT(p, caplen);
 156                 break;
 157         }
 158
 159         return h_size;
 160 trunc:
 161         ND_PRINT("%s", tstr);
 162         return h_size;
 163 }
 164
 165 #endif /* defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H) */