print-nflog.c revision 1.2 
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 1.2 2017/01/24 23:29:14 christos Exp $");
31#endif
32
33#ifdef HAVE_CONFIG_H
34#include "config.h"
35#endif
36
37#include <netdissect-stdinc.h>
38
39#include "netdissect.h"
40
41#if defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H)
42#include <pcap/nflog.h>
43
44static const struct tok nflog_values[] = {
45	{ AF_INET,		"IPv4" },
46#ifdef AF_INET6
47	{ AF_INET6,		"IPv6" },
48#endif /*AF_INET6*/
49	{ 0,			NULL }
50};
51
52static inline void
53nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
54{
55	ND_PRINT((ndo, "version %d, resource ID %d", hdr->nflog_version, ntohs(hdr->nflog_rid)));
56
57	if (!ndo->ndo_qflag) {
58		ND_PRINT((ndo,", family %s (%d)",
59						  tok2str(nflog_values, "Unknown",
60								  hdr->nflog_family),
61						  hdr->nflog_family));
62		} else {
63		ND_PRINT((ndo,", %s",
64						  tok2str(nflog_values,
65								  "Unknown NFLOG (0x%02x)",
66								  hdr->nflog_family)));
67		}
68
69	ND_PRINT((ndo, ", length %u: ", length));
70}
71
72u_int
73nflog_if_print(netdissect_options *ndo,
74			   const struct pcap_pkthdr *h, const u_char *p)
75{
76	const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
77	const nflog_tlv_t *tlv;
78	uint16_t size;
79	uint16_t h_size = sizeof(nflog_hdr_t);
80	u_int caplen = h->caplen;
81	u_int length = h->len;
82
83	if (caplen < (int) sizeof(nflog_hdr_t) || length < (int) sizeof(nflog_hdr_t)) {
84		ND_PRINT((ndo, "[|nflog]"));
85		return h_size;
86	}
87
88	if (hdr->nflog_version != 0) {
89		ND_PRINT((ndo, "version %u (unknown)", hdr->nflog_version));
90		return h_size;
91	}
92
93	if (ndo->ndo_eflag)
94		nflog_hdr_print(ndo, hdr, length);
95
96	p += sizeof(nflog_hdr_t);
97	length -= sizeof(nflog_hdr_t);
98	caplen -= sizeof(nflog_hdr_t);
99
100	while (length > 0) {
101		/* We have some data.  Do we have enough for the TLV header? */
102		if (caplen < sizeof(nflog_tlv_t) || length < sizeof(nflog_tlv_t)) {
103			/* No. */
104			ND_PRINT((ndo, "[|nflog]"));
105			return h_size;
106		}
107
108		tlv = (const nflog_tlv_t *) p;
109		size = tlv->tlv_length;
110		if (size % 4 != 0)
111			size += 4 - size % 4;
112
113		/* Is the TLV's length less than the minimum? */
114		if (size < sizeof(nflog_tlv_t)) {
115			/* Yes. Give up now. */
116			ND_PRINT((ndo, "[|nflog]"));
117			return h_size;
118		}
119
120		/* Do we have enough data for the full TLV? */
121		if (caplen < size || length < size) {
122			/* No. */
123			ND_PRINT((ndo, "[|nflog]"));
124			return h_size;
125		}
126
127		if (tlv->tlv_type == NFULA_PAYLOAD) {
128			/*
129			 * This TLV's data is the packet payload.
130			 * Skip past the TLV header, and break out
131			 * of the loop so we print the packet data.
132			 */
133			p += sizeof(nflog_tlv_t);
134			h_size += sizeof(nflog_tlv_t);
135			length -= sizeof(nflog_tlv_t);
136			caplen -= sizeof(nflog_tlv_t);
137			break;
138		}
139
140		p += size;
141		h_size += size;
142		length -= size;
143		caplen -= size;
144	}
145
146	switch (hdr->nflog_family) {
147
148	case AF_INET:
149		ip_print(ndo, p, length);
150		break;
151
152#ifdef AF_INET6
153	case AF_INET6:
154		ip6_print(ndo, p, length);
155		break;
156#endif /* AF_INET6 */
157
158	default:
159		if (!ndo->ndo_eflag)
160			nflog_hdr_print(ndo, hdr,
161				length + sizeof(nflog_hdr_t));
162
163		if (!ndo->ndo_suppress_default_print)
164			ND_DEFAULTPRINT(p, caplen);
165		break;
166	}
167
168	return h_size;
169}
170
171#endif /* defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H) */
172