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 */ 52typedef 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#define NFLOG_HDR_LEN sizeof(nflog_hdr_t) 59 60typedef struct nflog_tlv { 61 nd_uint16_t tlv_length; /* tlv length */ 62 nd_uint16_t tlv_type; /* tlv type */ 63 /* value follows this */ 64} nflog_tlv_t; 65 66#define NFLOG_TLV_LEN sizeof(nflog_tlv_t) 67 68typedef struct nflog_packet_hdr { 69 nd_uint16_t hw_protocol; /* hw protocol */ 70 nd_uint8_t hook; /* netfilter hook */ 71 nd_byte pad[1]; /* padding to 32 bits */ 72} nflog_packet_hdr_t; 73 74typedef struct nflog_hwaddr { 75 nd_uint16_t hw_addrlen; /* address length */ 76 nd_byte pad[2]; /* padding to 32-bit boundary */ 77 nd_byte hw_addr[8]; /* address, up to 8 bytes */ 78} nflog_hwaddr_t; 79 80typedef struct nflog_timestamp { 81 nd_uint64_t sec; 82 nd_uint64_t usec; 83} nflog_timestamp_t; 84 85/* 86 * TLV types. 87 */ 88#define NFULA_PACKET_HDR 1 /* nflog_packet_hdr_t */ 89#define NFULA_MARK 2 /* packet mark from skbuff */ 90#define NFULA_TIMESTAMP 3 /* nflog_timestamp_t for skbuff's time stamp */ 91#define NFULA_IFINDEX_INDEV 4 /* ifindex of device on which packet received (possibly bridge group) */ 92#define NFULA_IFINDEX_OUTDEV 5 /* ifindex of device on which packet transmitted (possibly bridge group) */ 93#define NFULA_IFINDEX_PHYSINDEV 6 /* ifindex of physical device on which packet received (not bridge group) */ 94#define NFULA_IFINDEX_PHYSOUTDEV 7 /* ifindex of physical device on which packet transmitted (not bridge group) */ 95#define NFULA_HWADDR 8 /* nflog_hwaddr_t for hardware address */ 96#define NFULA_PAYLOAD 9 /* packet payload */ 97#define NFULA_PREFIX 10 /* text string - null-terminated, count includes NUL */ 98#define NFULA_UID 11 /* UID owning socket on which packet was sent/received */ 99#define NFULA_SEQ 12 /* sequence number of packets on this NFLOG socket */ 100#define NFULA_SEQ_GLOBAL 13 /* sequence number of pakets on all NFLOG sockets */ 101#define NFULA_GID 14 /* GID owning socket on which packet was sent/received */ 102#define NFULA_HWTYPE 15 /* ARPHRD_ type of skbuff's device */ 103#define NFULA_HWHEADER 16 /* skbuff's MAC-layer header */ 104#define NFULA_HWLEN 17 /* length of skbuff's MAC-layer header */ 105 106static const struct tok nflog_values[] = { 107 { AF_INET, "IPv4" }, 108 { AF_INET6, "IPv6" }, 109 { 0, NULL } 110}; 111 112static void 113nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length) 114{ 115 ND_PRINT("version %u, resource ID %u", 116 GET_U_1(hdr->nflog_version), GET_BE_U_2(hdr->nflog_rid)); 117 118 if (!ndo->ndo_qflag) { 119 ND_PRINT(", family %s (%u)", 120 tok2str(nflog_values, "Unknown", 121 GET_U_1(hdr->nflog_family)), 122 GET_U_1(hdr->nflog_family)); 123 } else { 124 ND_PRINT(", %s", 125 tok2str(nflog_values, 126 "Unknown NFLOG (0x%02x)", 127 GET_U_1(hdr->nflog_family))); 128 } 129 130 ND_PRINT(", length %u: ", length); 131} 132 133void 134nflog_if_print(netdissect_options *ndo, 135 const struct pcap_pkthdr *h, const u_char *p) 136{ 137 const nflog_hdr_t *hdr = (const nflog_hdr_t *)p; 138 uint16_t size; 139 uint16_t h_size = NFLOG_HDR_LEN; 140 u_int caplen = h->caplen; 141 u_int length = h->len; 142 143 ndo->ndo_protocol = "nflog"; 144 if (caplen < NFLOG_HDR_LEN) { 145 nd_print_trunc(ndo); 146 ndo->ndo_ll_hdr_len += caplen; 147 return; 148 } 149 ndo->ndo_ll_hdr_len += NFLOG_HDR_LEN; 150 151 ND_TCHECK_SIZE(hdr); 152 if (GET_U_1(hdr->nflog_version) != 0) { 153 ND_PRINT("version %u (unknown)", GET_U_1(hdr->nflog_version)); 154 return; 155 } 156 157 if (ndo->ndo_eflag) 158 nflog_hdr_print(ndo, hdr, length); 159 160 p += NFLOG_HDR_LEN; 161 length -= NFLOG_HDR_LEN; 162 caplen -= NFLOG_HDR_LEN; 163 164 while (length > 0) { 165 const nflog_tlv_t *tlv; 166 167 /* We have some data. Do we have enough for the TLV header? */ 168 if (caplen < NFLOG_TLV_LEN) 169 goto trunc; /* No. */ 170 171 tlv = (const nflog_tlv_t *) p; 172 ND_TCHECK_SIZE(tlv); 173 size = GET_HE_U_2(tlv->tlv_length); 174 if (size % 4 != 0) 175 size += 4 - size % 4; 176 177 /* Is the TLV's length less than the minimum? */ 178 if (size < NFLOG_TLV_LEN) 179 goto trunc; /* Yes. Give up now. */ 180 181 /* Do we have enough data for the full TLV? */ 182 if (caplen < size) 183 goto trunc; /* No. */ 184 185 if (GET_HE_U_2(tlv->tlv_type) == NFULA_PAYLOAD) { 186 /* 187 * This TLV's data is the packet payload. 188 * Skip past the TLV header, and break out 189 * of the loop so we print the packet data. 190 */ 191 p += NFLOG_TLV_LEN; 192 h_size += NFLOG_TLV_LEN; 193 length -= NFLOG_TLV_LEN; 194 caplen -= NFLOG_TLV_LEN; 195 break; 196 } 197 198 p += size; 199 h_size += size; 200 length -= size; 201 caplen -= size; 202 } 203 204 switch (GET_U_1(hdr->nflog_family)) { 205 206 case AF_INET: 207 ip_print(ndo, p, length); 208 break; 209 210 case AF_INET6: 211 ip6_print(ndo, p, length); 212 break; 213 214 default: 215 if (!ndo->ndo_eflag) 216 nflog_hdr_print(ndo, hdr, 217 length + NFLOG_HDR_LEN); 218 219 if (!ndo->ndo_suppress_default_print) 220 ND_DEFAULTPRINT(p, caplen); 221 break; 222 } 223 224 ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN; 225 return; 226trunc: 227 nd_print_trunc(ndo); 228 ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN; 229} 230 231#endif /* DLT_NFLOG */ 232