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 #include <sys/cdefs.h>
29 #ifndef lint
30 __RCSID("$NetBSD: print-nflog.c,v 1.5 2024/09/02 16:15:32 christos Exp $");
31 #endif
32
33 /* \summary: DLT_NFLOG printer */
34
35 #include <config.h>
36
37 #include "netdissect-stdinc.h"
38
39 #include "netdissect.h"
40 #include "extract.h"
41
42 #ifdef DLT_NFLOG
43
44 /*
45 * Structure of an NFLOG header and TLV parts, as described at
46 * https://www.tcpdump.org/linktypes/LINKTYPE_NFLOG.html
47 *
48 * The NFLOG header is big-endian.
49 *
50 * The TLV length and type are in host byte order. The value is either
51 * big-endian or is an array of bytes in some externally-specified byte
52 * order (text string, link-layer address, link-layer header, packet
53 * data, etc.).
54 */
55 typedef struct nflog_hdr {
56 nd_uint8_t nflog_family; /* address family */
57 nd_uint8_t nflog_version; /* version */
58 nd_uint16_t nflog_rid; /* resource ID */
59 } nflog_hdr_t;
60
61 #define NFLOG_HDR_LEN sizeof(nflog_hdr_t)
62
63 typedef struct nflog_tlv {
64 nd_uint16_t tlv_length; /* tlv length */
65 nd_uint16_t tlv_type; /* tlv type */
66 /* value follows this */
67 } nflog_tlv_t;
68
69 #define NFLOG_TLV_LEN sizeof(nflog_tlv_t)
70
71 typedef struct nflog_packet_hdr {
72 nd_uint16_t hw_protocol; /* hw protocol */
73 nd_uint8_t hook; /* netfilter hook */
74 nd_byte pad[1]; /* padding to 32 bits */
75 } nflog_packet_hdr_t;
76
77 typedef struct nflog_hwaddr {
78 nd_uint16_t hw_addrlen; /* address length */
79 nd_byte pad[2]; /* padding to 32-bit boundary */
80 nd_byte hw_addr[8]; /* address, up to 8 bytes */
81 } nflog_hwaddr_t;
82
83 typedef struct nflog_timestamp {
84 nd_uint64_t sec;
85 nd_uint64_t usec;
86 } nflog_timestamp_t;
87
88 /*
89 * TLV types.
90 */
91 #define NFULA_PACKET_HDR 1 /* nflog_packet_hdr_t */
92 #define NFULA_MARK 2 /* packet mark from skbuff */
93 #define NFULA_TIMESTAMP 3 /* nflog_timestamp_t for skbuff's time stamp */
94 #define NFULA_IFINDEX_INDEV 4 /* ifindex of device on which packet received (possibly bridge group) */
95 #define NFULA_IFINDEX_OUTDEV 5 /* ifindex of device on which packet transmitted (possibly bridge group) */
96 #define NFULA_IFINDEX_PHYSINDEV 6 /* ifindex of physical device on which packet received (not bridge group) */
97 #define NFULA_IFINDEX_PHYSOUTDEV 7 /* ifindex of physical device on which packet transmitted (not bridge group) */
98 #define NFULA_HWADDR 8 /* nflog_hwaddr_t for hardware address */
99 #define NFULA_PAYLOAD 9 /* packet payload */
100 #define NFULA_PREFIX 10 /* text string - null-terminated, count includes NUL */
101 #define NFULA_UID 11 /* UID owning socket on which packet was sent/received */
102 #define NFULA_SEQ 12 /* sequence number of packets on this NFLOG socket */
103 #define NFULA_SEQ_GLOBAL 13 /* sequence number of packets on all NFLOG sockets */
104 #define NFULA_GID 14 /* GID owning socket on which packet was sent/received */
105 #define NFULA_HWTYPE 15 /* ARPHRD_ type of skbuff's device */
106 #define NFULA_HWHEADER 16 /* skbuff's MAC-layer header */
107 #define NFULA_HWLEN 17 /* length of skbuff's MAC-layer header */
108
109 /*
110 * Define two constants specifically for the two AF code points from the
111 * LINKTYPE_NFLOG specification above and use these constants instead of
112 * AF_INET and AF_INET6. This is the only way to dissect the "wire" encoding
113 * correctly because some BSD systems define AF_INET6 differently from Linux
114 * (see af.h) and Haiku defines both AF_INET and AF_INET6 differently from
115 * Linux.
116 */
117 #define NFLOG_AF_INET 2
118 #define NFLOG_AF_INET6 10
119 static const struct tok nflog_values[] = {
120 { NFLOG_AF_INET, "IPv4" },
121 { NFLOG_AF_INET6, "IPv6" },
122 { 0, NULL }
123 };
124
125 static void
nflog_hdr_print(netdissect_options * ndo,const nflog_hdr_t * hdr,u_int length)126 nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
127 {
128 ND_PRINT("version %u, resource ID %u",
129 GET_U_1(hdr->nflog_version), GET_BE_U_2(hdr->nflog_rid));
130
131 if (!ndo->ndo_qflag) {
132 ND_PRINT(", family %s (%u)",
133 tok2str(nflog_values, "Unknown",
134 GET_U_1(hdr->nflog_family)),
135 GET_U_1(hdr->nflog_family));
136 } else {
137 ND_PRINT(", %s",
138 tok2str(nflog_values,
139 "Unknown NFLOG (0x%02x)",
140 GET_U_1(hdr->nflog_family)));
141 }
142
143 ND_PRINT(", length %u: ", length);
144 }
145
146 void
nflog_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)147 nflog_if_print(netdissect_options *ndo,
148 const struct pcap_pkthdr *h, const u_char *p)
149 {
150 const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
151 uint16_t size;
152 uint16_t h_size = NFLOG_HDR_LEN;
153 u_int caplen = h->caplen;
154 u_int length = h->len;
155
156 ndo->ndo_protocol = "nflog";
157 if (caplen < NFLOG_HDR_LEN) {
158 nd_print_trunc(ndo);
159 ndo->ndo_ll_hdr_len += caplen;
160 return;
161 }
162 ndo->ndo_ll_hdr_len += NFLOG_HDR_LEN;
163
164 ND_TCHECK_SIZE(hdr);
165 if (GET_U_1(hdr->nflog_version) != 0) {
166 ND_PRINT("version %u (unknown)", GET_U_1(hdr->nflog_version));
167 return;
168 }
169
170 if (ndo->ndo_eflag)
171 nflog_hdr_print(ndo, hdr, length);
172
173 p += NFLOG_HDR_LEN;
174 length -= NFLOG_HDR_LEN;
175 caplen -= NFLOG_HDR_LEN;
176
177 while (length > 0) {
178 const nflog_tlv_t *tlv;
179
180 /* We have some data. Do we have enough for the TLV header? */
181 if (caplen < NFLOG_TLV_LEN)
182 goto trunc; /* No. */
183
184 tlv = (const nflog_tlv_t *) p;
185 ND_TCHECK_SIZE(tlv);
186 size = GET_HE_U_2(tlv->tlv_length);
187 if (size % 4 != 0)
188 size += 4 - size % 4;
189
190 /* Is the TLV's length less than the minimum? */
191 if (size < NFLOG_TLV_LEN)
192 goto trunc; /* Yes. Give up now. */
193
194 /* Do we have enough data for the full TLV? */
195 if (caplen < size)
196 goto trunc; /* No. */
197
198 if (GET_HE_U_2(tlv->tlv_type) == NFULA_PAYLOAD) {
199 /*
200 * This TLV's data is the packet payload.
201 * Skip past the TLV header, and break out
202 * of the loop so we print the packet data.
203 */
204 p += NFLOG_TLV_LEN;
205 h_size += NFLOG_TLV_LEN;
206 length -= NFLOG_TLV_LEN;
207 caplen -= NFLOG_TLV_LEN;
208 break;
209 }
210
211 p += size;
212 h_size += size;
213 length -= size;
214 caplen -= size;
215 }
216
217 switch (GET_U_1(hdr->nflog_family)) {
218
219 case NFLOG_AF_INET:
220 ip_print(ndo, p, length);
221 break;
222
223 case NFLOG_AF_INET6:
224 ip6_print(ndo, p, length);
225 break;
226
227 default:
228 if (!ndo->ndo_eflag)
229 nflog_hdr_print(ndo, hdr,
230 length + NFLOG_HDR_LEN);
231
232 if (!ndo->ndo_suppress_default_print)
233 ND_DEFAULTPRINT(p, caplen);
234 break;
235 }
236
237 ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN;
238 return;
239 trunc:
240 nd_print_trunc(ndo);
241 ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN;
242 }
243
244 #endif /* DLT_NFLOG */
245