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 #include "extract.h"
  38
  39 #ifdef DLT_NFLOG
  40
  41 /*
  42  * Structure of an NFLOG header and TLV parts, as described at
  43  * https://www.tcpdump.org/linktypes/LINKTYPE_NFLOG.html
  44  *
  45  * The NFLOG header is big-endian.
  46  *
  47  * The TLV length and type are in host byte order.  The value is either
  48  * big-endian or is an array of bytes in some externally-specified byte
  49  * order (text string, link-layer address, link-layer header, packet
  50  * data, etc.).
  51  */
  52 typedef struct nflog_hdr {
  53         nd_uint8_t      nflog_family;           /* address family */
  54         nd_uint8_t      nflog_version;          /* version */
  55         nd_uint16_t     nflog_rid;              /* resource ID */
  56 } nflog_hdr_t;
  57
  58 typedef struct nflog_tlv {
  59         nd_uint16_t     tlv_length;             /* tlv length */
  60         nd_uint16_t     tlv_type;               /* tlv type */
  61         /* value follows this */
  62 } nflog_tlv_t;
  63
  64 typedef struct nflog_packet_hdr {
  65         nd_uint16_t     hw_protocol;    /* hw protocol */
  66         nd_uint8_t      hook;           /* netfilter hook */
  67         nd_byte         pad[1];         /* padding to 32 bits */
  68 } nflog_packet_hdr_t;
  69
  70 typedef struct nflog_hwaddr {
  71         nd_uint16_t     hw_addrlen;     /* address length */
  72         nd_byte         pad[2];         /* padding to 32-bit boundary */
  73         nd_byte         hw_addr[8];     /* address, up to 8 bytes */
  74 } nflog_hwaddr_t;
  75
  76 typedef struct nflog_timestamp {
  77         nd_uint64_t     sec;
  78         nd_uint64_t     usec;
  79 } nflog_timestamp_t;
  80
  81 /*
  82  * TLV types.
  83  */
  84 #define NFULA_PACKET_HDR                1       /* nflog_packet_hdr_t */
  85 #define NFULA_MARK                      2       /* packet mark from skbuff */
  86 #define NFULA_TIMESTAMP                 3       /* nflog_timestamp_t for skbuff's time stamp */
  87 #define NFULA_IFINDEX_INDEV             4       /* ifindex of device on which packet received (possibly bridge group) */
  88 #define NFULA_IFINDEX_OUTDEV            5       /* ifindex of device on which packet transmitted (possibly bridge group) */
  89 #define NFULA_IFINDEX_PHYSINDEV         6       /* ifindex of physical device on which packet received (not bridge group) */
  90 #define NFULA_IFINDEX_PHYSOUTDEV        7       /* ifindex of physical device on which packet transmitted (not bridge group) */
  91 #define NFULA_HWADDR                    8       /* nflog_hwaddr_t for hardware address */
  92 #define NFULA_PAYLOAD                   9       /* packet payload */
  93 #define NFULA_PREFIX                    10      /* text string - null-terminated, count includes NUL */
  94 #define NFULA_UID                       11      /* UID owning socket on which packet was sent/received */
  95 #define NFULA_SEQ                       12      /* sequence number of packets on this NFLOG socket */
  96 #define NFULA_SEQ_GLOBAL                13      /* sequence number of pakets on all NFLOG sockets */
  97 #define NFULA_GID                       14      /* GID owning socket on which packet was sent/received */
  98 #define NFULA_HWTYPE                    15      /* ARPHRD_ type of skbuff's device */
  99 #define NFULA_HWHEADER                  16      /* skbuff's MAC-layer header */
 100 #define NFULA_HWLEN                     17      /* length of skbuff's MAC-layer header */
 101
 102 static const struct tok nflog_values[] = {
 103         { AF_INET,              "IPv4" },
 104 #ifdef AF_INET6
 105         { AF_INET6,             "IPv6" },
 106 #endif /*AF_INET6*/
 107         { 0,                    NULL }
 108 };
 109
 110 static void
 111 nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
 112 {
 113         ND_PRINT("version %u, resource ID %u",
 114             EXTRACT_U_1(hdr->nflog_version), EXTRACT_BE_U_2(hdr->nflog_rid));
 115
 116         if (!ndo->ndo_qflag) {
 117                 ND_PRINT(", family %s (%u)",
 118                          tok2str(nflog_values, "Unknown",
 119                                  EXTRACT_U_1(hdr->nflog_family)),
 120                          EXTRACT_U_1(hdr->nflog_family));
 121                 } else {
 122                 ND_PRINT(", %s",
 123                          tok2str(nflog_values,
 124                                  "Unknown NFLOG (0x%02x)",
 125                          EXTRACT_U_1(hdr->nflog_family)));
 126                 }
 127
 128         ND_PRINT(", length %u: ", length);
 129 }
 130
 131 u_int
 132 nflog_if_print(netdissect_options *ndo,
 133                            const struct pcap_pkthdr *h, const u_char *p)
 134 {
 135         const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
 136         uint16_t size;
 137         uint16_t h_size = sizeof(nflog_hdr_t);
 138         u_int caplen = h->caplen;
 139         u_int length = h->len;
 140
 141         ndo->ndo_protocol = "nflog_if";
 142         if (caplen < sizeof(nflog_hdr_t))
 143                 goto trunc;
 144
 145         ND_TCHECK_SIZE(hdr);
 146         if (EXTRACT_U_1(hdr->nflog_version) != 0) {
 147                 ND_PRINT("version %u (unknown)", EXTRACT_U_1(hdr->nflog_version));
 148                 return h_size;
 149         }
 150
 151         if (ndo->ndo_eflag)
 152                 nflog_hdr_print(ndo, hdr, length);
 153
 154         p += sizeof(nflog_hdr_t);
 155         length -= sizeof(nflog_hdr_t);
 156         caplen -= sizeof(nflog_hdr_t);
 157
 158         while (length > 0) {
 159                 const nflog_tlv_t *tlv;
 160
 161                 /* We have some data.  Do we have enough for the TLV header? */
 162                 if (caplen < sizeof(nflog_tlv_t))
 163                         goto trunc;     /* No. */
 164
 165                 tlv = (const nflog_tlv_t *) p;
 166                 ND_TCHECK_SIZE(tlv);
 167                 size = EXTRACT_HE_U_2(tlv->tlv_length);
 168                 if (size % 4 != 0)
 169                         size += 4 - size % 4;
 170
 171                 /* Is the TLV's length less than the minimum? */
 172                 if (size < sizeof(nflog_tlv_t))
 173                         goto trunc;     /* Yes. Give up now. */
 174
 175                 /* Do we have enough data for the full TLV? */
 176                 if (caplen < size)
 177                         goto trunc;     /* No. */
 178
 179                 if (EXTRACT_HE_U_2(tlv->tlv_type) == NFULA_PAYLOAD) {
 180                         /*
 181                          * This TLV's data is the packet payload.
 182                          * Skip past the TLV header, and break out
 183                          * of the loop so we print the packet data.
 184                          */
 185                         p += sizeof(nflog_tlv_t);
 186                         h_size += sizeof(nflog_tlv_t);
 187                         length -= sizeof(nflog_tlv_t);
 188                         caplen -= sizeof(nflog_tlv_t);
 189                         break;
 190                 }
 191
 192                 p += size;
 193                 h_size += size;
 194                 length -= size;
 195                 caplen -= size;
 196         }
 197
 198         switch (EXTRACT_U_1(hdr->nflog_family)) {
 199
 200         case AF_INET:
 201                 ip_print(ndo, p, length);
 202                 break;
 203
 204 #ifdef AF_INET6
 205         case AF_INET6:
 206                 ip6_print(ndo, p, length);
 207                 break;
 208 #endif /* AF_INET6 */
 209
 210         default:
 211                 if (!ndo->ndo_eflag)
 212                         nflog_hdr_print(ndo, hdr,
 213                                 length + sizeof(nflog_hdr_t));
 214
 215                 if (!ndo->ndo_suppress_default_print)
 216                         ND_DEFAULTPRINT(p, caplen);
 217                 break;
 218         }
 219
 220         return h_size;
 221 trunc:
 222         nd_print_trunc(ndo);
 223         return h_size;
 224 }
 225
 226 #endif /* DLT_NFLOG */