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 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #include <tcpdump-stdinc.h>
  33
  34 #include "netdissect.h"
  35
  36 #if defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H)
  37 #include <pcap/nflog.h>
  38
  39 static const struct tok nflog_values[] = {
  40         { AF_INET,              "IPv4" },
  41         { AF_INET6,             "IPv6" },
  42         { 0,                            NULL }
  43 };
  44
  45 static inline void
  46 nflog_hdr_print(struct netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
  47 {
  48         ND_PRINT((ndo, "version %d, resource ID %d", hdr->nflog_version, ntohs(hdr->nflog_rid)));
  49
  50         if (!ndo->ndo_qflag) {
  51                 ND_PRINT((ndo,", family %s (%d)",
  52                                                   tok2str(nflog_values, "Unknown",
  53                                                                   hdr->nflog_family),
  54                                                   hdr->nflog_family));
  55                 } else {
  56                 ND_PRINT((ndo,", %s",
  57                                                   tok2str(nflog_values,
  58                                                                   "Unknown NFLOG (0x%02x)",
  59                                                                   hdr->nflog_family)));
  60                 }
  61
  62         ND_PRINT((ndo, ", length %u: ", length));
  63 }
  64
  65 u_int
  66 nflog_if_print(struct netdissect_options *ndo,
  67                            const struct pcap_pkthdr *h, const u_char *p)
  68 {
  69         const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
  70         const nflog_tlv_t *tlv;
  71         u_int16_t size;
  72         u_int16_t h_size = sizeof(nflog_hdr_t);
  73         u_int caplen = h->caplen;
  74         u_int length = h->len;
  75
  76         if (caplen < (int) sizeof(nflog_hdr_t) || length < (int) sizeof(nflog_hdr_t)) {
  77                 ND_PRINT((ndo, "[|nflog]"));
  78                 return h_size;
  79         }
  80
  81         if (!(hdr->nflog_version) == 0) {
  82                 ND_PRINT((ndo, "version %u (unknown)", hdr->nflog_version));
  83                 return h_size;
  84         }
  85
  86         if (ndo->ndo_eflag)
  87                 nflog_hdr_print(ndo, hdr, length);
  88
  89         p += sizeof(nflog_hdr_t);
  90         length -= sizeof(nflog_hdr_t);
  91         caplen -= sizeof(nflog_hdr_t);
  92
  93         while (length > 0) {
  94                 /* We have some data.  Do we have enough for the TLV header? */
  95                 if (caplen < sizeof(nflog_tlv_t) || length < sizeof(nflog_tlv_t)) {
  96                         /* No. */
  97                         ND_PRINT((ndo, "[|nflog]"));
  98                         return h_size;
  99                 }
 100
 101                 tlv = (const nflog_tlv_t *) p;
 102                 size = tlv->tlv_length;
 103                 if (size % 4 != 0)
 104                         size += 4 - size % 4;
 105
 106                 /* Is the TLV's length less than the minimum? */
 107                 if (size < sizeof(nflog_tlv_t)) {
 108                         /* Yes. Give up now. */
 109                         ND_PRINT((ndo, "[|nflog]"));
 110                         return h_size;
 111                 }
 112
 113                 /* Do we have enough data for the full TLV? */
 114                 if (caplen < size || length < size) {
 115                         /* No. */
 116                         ND_PRINT((ndo, "[|nflog]"));
 117                         return h_size;
 118                 }
 119
 120                 if (tlv->tlv_type == NFULA_PAYLOAD) {
 121                         /*
 122                          * This TLV's data is the packet payload.
 123                          * Skip past the TLV header, and break out
 124                          * of the loop so we print the packet data.
 125                          */
 126                         p += sizeof(nflog_tlv_t);
 127                         h_size += sizeof(nflog_tlv_t);
 128                         length -= sizeof(nflog_tlv_t);
 129                         caplen -= sizeof(nflog_tlv_t);
 130                         break;
 131                 }
 132
 133                 p += size;
 134                 h_size += size;
 135                 length -= size;
 136                 caplen -= size;
 137         }
 138
 139         switch (hdr->nflog_family) {
 140
 141         case AF_INET:
 142                 ip_print(ndo, p, length);
 143                 break;
 144
 145 #ifdef INET6
 146         case AF_INET6:
 147                 ip6_print(ndo, p, length);
 148                 break;
 149 #endif /*INET6*/
 150
 151         default:
 152                 if (!ndo->ndo_eflag)
 153                         nflog_hdr_print(ndo, hdr,
 154                                 length + sizeof(nflog_hdr_t));
 155
 156                 if (!ndo->ndo_suppress_default_print)
 157                         ndo->ndo_default_print(ndo, p, caplen);
 158                 break;
 159         }
 160
 161         return h_size;
 162 }
 163
 164 #endif /* defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H) */