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 #include <config.h>
  31
  32 #include "netdissect-stdinc.h"
  33
  34 #define ND_LONGJMP_FROM_TCHECK
  35 #include "netdissect.h"
  36 #include "extract.h"
  37
  38 #ifdef DLT_NFLOG
  39
  40 /*
  41  * Structure of an NFLOG header and TLV parts, as described at
  42  * https://www.tcpdump.org/linktypes/LINKTYPE_NFLOG.html
  43  *
  44  * The NFLOG header is big-endian.
  45  *
  46  * The TLV length and type are in host byte order.  The value is either
  47  * big-endian or is an array of bytes in some externally-specified byte
  48  * order (text string, link-layer address, link-layer header, packet
  49  * data, etc.).
  50  */
  51 typedef struct nflog_hdr {
  52         nd_uint8_t      nflog_family;           /* address family */
  53         nd_uint8_t      nflog_version;          /* version */
  54         nd_uint16_t     nflog_rid;              /* resource ID */
  55 } nflog_hdr_t;
  56
  57 #define NFLOG_HDR_LEN sizeof(nflog_hdr_t)
  58
  59 typedef struct nflog_tlv {
  60         nd_uint16_t     tlv_length;             /* tlv length */
  61         nd_uint16_t     tlv_type;               /* tlv type */
  62         /* value follows this */
  63 } nflog_tlv_t;
  64
  65 #define NFLOG_TLV_LEN sizeof(nflog_tlv_t)
  66
  67 typedef struct nflog_packet_hdr {
  68         nd_uint16_t     hw_protocol;    /* hw protocol */
  69         nd_uint8_t      hook;           /* netfilter hook */
  70         nd_byte         pad[1];         /* padding to 32 bits */
  71 } nflog_packet_hdr_t;
  72
  73 typedef struct nflog_hwaddr {
  74         nd_uint16_t     hw_addrlen;     /* address length */
  75         nd_byte         pad[2];         /* padding to 32-bit boundary */
  76         nd_byte         hw_addr[8];     /* address, up to 8 bytes */
  77 } nflog_hwaddr_t;
  78
  79 typedef struct nflog_timestamp {
  80         nd_uint64_t     sec;
  81         nd_uint64_t     usec;
  82 } nflog_timestamp_t;
  83
  84 /*
  85  * TLV types.
  86  */
  87 #define NFULA_PACKET_HDR                1       /* nflog_packet_hdr_t */
  88 #define NFULA_MARK                      2       /* packet mark from skbuff */
  89 #define NFULA_TIMESTAMP                 3       /* nflog_timestamp_t for skbuff's time stamp */
  90 #define NFULA_IFINDEX_INDEV             4       /* ifindex of device on which packet received (possibly bridge group) */
  91 #define NFULA_IFINDEX_OUTDEV            5       /* ifindex of device on which packet transmitted (possibly bridge group) */
  92 #define NFULA_IFINDEX_PHYSINDEV         6       /* ifindex of physical device on which packet received (not bridge group) */
  93 #define NFULA_IFINDEX_PHYSOUTDEV        7       /* ifindex of physical device on which packet transmitted (not bridge group) */
  94 #define NFULA_HWADDR                    8       /* nflog_hwaddr_t for hardware address */
  95 #define NFULA_PAYLOAD                   9       /* packet payload */
  96 #define NFULA_PREFIX                    10      /* text string - null-terminated, count includes NUL */
  97 #define NFULA_UID                       11      /* UID owning socket on which packet was sent/received */
  98 #define NFULA_SEQ                       12      /* sequence number of packets on this NFLOG socket */
  99 #define NFULA_SEQ_GLOBAL                13      /* sequence number of packets on all NFLOG sockets */
 100 #define NFULA_GID                       14      /* GID owning socket on which packet was sent/received */
 101 #define NFULA_HWTYPE                    15      /* ARPHRD_ type of skbuff's device */
 102 #define NFULA_HWHEADER                  16      /* skbuff's MAC-layer header */
 103 #define NFULA_HWLEN                     17      /* length of skbuff's MAC-layer header */
 104
 105 /*
 106  * Define two constants specifically for the two AF code points from the
 107  * LINKTYPE_NFLOG specification above and use these constants instead of
 108  * AF_INET and AF_INET6.  This is the only way to dissect the "wire" encoding
 109  * correctly because some BSD systems define AF_INET6 differently from Linux
 110  * (see af.h) and Haiku defines both AF_INET and AF_INET6 differently from
 111  * Linux.
 112  */
 113 #define NFLOG_AF_INET   2
 114 #define NFLOG_AF_INET6 10
 115 static const struct tok nflog_values[] = {
 116         { NFLOG_AF_INET,        "IPv4" },
 117         { NFLOG_AF_INET6,       "IPv6" },
 118         { 0,                    NULL }
 119 };
 120
 121 static void
 122 nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
 123 {
 124         ND_PRINT("version %u, resource ID %u",
 125             GET_U_1(hdr->nflog_version), GET_BE_U_2(hdr->nflog_rid));
 126
 127         if (!ndo->ndo_qflag) {
 128                 ND_PRINT(", family %s (%u)",
 129                          tok2str(nflog_values, "Unknown",
 130                                  GET_U_1(hdr->nflog_family)),
 131                          GET_U_1(hdr->nflog_family));
 132                 } else {
 133                 ND_PRINT(", %s",
 134                          tok2str(nflog_values,
 135                                  "Unknown NFLOG (0x%02x)",
 136                          GET_U_1(hdr->nflog_family)));
 137                 }
 138
 139         ND_PRINT(", length %u: ", length);
 140 }
 141
 142 void
 143 nflog_if_print(netdissect_options *ndo,
 144                const struct pcap_pkthdr *h, const u_char *p)
 145 {
 146         const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
 147         uint16_t size;
 148         uint16_t h_size = NFLOG_HDR_LEN;
 149         u_int caplen = h->caplen;
 150         u_int length = h->len;
 151
 152         ndo->ndo_protocol = "nflog";
 153         ND_ICHECK_ZU(length, <, NFLOG_HDR_LEN);
 154
 155         ND_TCHECK_SIZE(hdr);
 156         ndo->ndo_ll_hdr_len += NFLOG_HDR_LEN;
 157
 158         if (GET_U_1(hdr->nflog_version) != 0) {
 159                 ND_PRINT("version %u (unknown)", GET_U_1(hdr->nflog_version));
 160                 return;
 161         }
 162
 163         if (ndo->ndo_eflag)
 164                 nflog_hdr_print(ndo, hdr, length);
 165
 166         p += NFLOG_HDR_LEN;
 167         length -= NFLOG_HDR_LEN;
 168         caplen -= NFLOG_HDR_LEN;
 169
 170         while (length != 0) {
 171                 const nflog_tlv_t *tlv;
 172
 173                 ND_ICHECK_ZU(length, <, NFLOG_TLV_LEN);
 174                 tlv = (const nflog_tlv_t *) p;
 175                 /* Do we have enough data for the TLV header? */
 176                 ND_TCHECK_SIZE(tlv);
 177                 size = GET_HE_U_2(tlv->tlv_length);
 178                 if (size % 4 != 0)
 179                         size += 4 - size % 4;
 180
 181                 /* Is the TLV's length less than the minimum? */
 182                 ND_ICHECK_ZU(size, <, NFLOG_TLV_LEN);
 183                 ND_ICHECK_U(length, <, size);
 184
 185                 /* Do we have enough data for the full TLV? */
 186                 ND_TCHECK_LEN(tlv, size);
 187
 188                 if (GET_HE_U_2(tlv->tlv_type) == NFULA_PAYLOAD) {
 189                         /*
 190                          * This TLV's data is the packet payload.
 191                          * Skip past the TLV header, and break out
 192                          * of the loop so we print the packet data.
 193                          */
 194                         p += NFLOG_TLV_LEN;
 195                         h_size += NFLOG_TLV_LEN;
 196                         length -= NFLOG_TLV_LEN;
 197                         caplen -= NFLOG_TLV_LEN;
 198                         break;
 199                 }
 200
 201                 p += size;
 202                 h_size += size;
 203                 length -= size;
 204                 caplen -= size;
 205         }
 206
 207         switch (GET_U_1(hdr->nflog_family)) {
 208
 209         case NFLOG_AF_INET:
 210                 ip_print(ndo, p, length);
 211                 break;
 212
 213         case NFLOG_AF_INET6:
 214                 ip6_print(ndo, p, length);
 215                 break;
 216
 217         default:
 218                 if (!ndo->ndo_eflag)
 219                         nflog_hdr_print(ndo, hdr,
 220                                         length + NFLOG_HDR_LEN);
 221
 222                 if (!ndo->ndo_suppress_default_print)
 223                         ND_DEFAULTPRINT(p, caplen);
 224                 break;
 225         }
 226
 227         ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN;
 228         return;
 229
 230 invalid:
 231         nd_print_invalid(ndo);
 232 }
 233
 234 #endif /* DLT_NFLOG */