print-nflog.c revision 1.3 
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 1.3 2017/02/05 04:05:05 spz Exp $");
31#endif
32
33/* \summary: DLT_NFLOG printer */
34
35#ifdef HAVE_CONFIG_H
36#include "config.h"
37#endif
38
39#include <netdissect-stdinc.h>
40
41#include "netdissect.h"
42
43#if defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H)
44#include <pcap/nflog.h>
45
46static const struct tok nflog_values[] = {
47	{ AF_INET,		"IPv4" },
48#ifdef AF_INET6
49	{ AF_INET6,		"IPv6" },
50#endif /*AF_INET6*/
51	{ 0,			NULL }
52};
53
54static inline void
55nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
56{
57	ND_PRINT((ndo, "version %d, resource ID %d", hdr->nflog_version, ntohs(hdr->nflog_rid)));
58
59	if (!ndo->ndo_qflag) {
60		ND_PRINT((ndo,", family %s (%d)",
61						  tok2str(nflog_values, "Unknown",
62								  hdr->nflog_family),
63						  hdr->nflog_family));
64		} else {
65		ND_PRINT((ndo,", %s",
66						  tok2str(nflog_values,
67								  "Unknown NFLOG (0x%02x)",
68								  hdr->nflog_family)));
69		}
70
71	ND_PRINT((ndo, ", length %u: ", length));
72}
73
74u_int
75nflog_if_print(netdissect_options *ndo,
76			   const struct pcap_pkthdr *h, const u_char *p)
77{
78	const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
79	const nflog_tlv_t *tlv;
80	uint16_t size;
81	uint16_t h_size = sizeof(nflog_hdr_t);
82	u_int caplen = h->caplen;
83	u_int length = h->len;
84
85	if (caplen < (int) sizeof(nflog_hdr_t) || length < (int) sizeof(nflog_hdr_t)) {
86		ND_PRINT((ndo, "[|nflog]"));
87		return h_size;
88	}
89
90	if (hdr->nflog_version != 0) {
91		ND_PRINT((ndo, "version %u (unknown)", hdr->nflog_version));
92		return h_size;
93	}
94
95	if (ndo->ndo_eflag)
96		nflog_hdr_print(ndo, hdr, length);
97
98	p += sizeof(nflog_hdr_t);
99	length -= sizeof(nflog_hdr_t);
100	caplen -= sizeof(nflog_hdr_t);
101
102	while (length > 0) {
103		/* We have some data.  Do we have enough for the TLV header? */
104		if (caplen < sizeof(nflog_tlv_t) || length < sizeof(nflog_tlv_t)) {
105			/* No. */
106			ND_PRINT((ndo, "[|nflog]"));
107			return h_size;
108		}
109
110		tlv = (const nflog_tlv_t *) p;
111		size = tlv->tlv_length;
112		if (size % 4 != 0)
113			size += 4 - size % 4;
114
115		/* Is the TLV's length less than the minimum? */
116		if (size < sizeof(nflog_tlv_t)) {
117			/* Yes. Give up now. */
118			ND_PRINT((ndo, "[|nflog]"));
119			return h_size;
120		}
121
122		/* Do we have enough data for the full TLV? */
123		if (caplen < size || length < size) {
124			/* No. */
125			ND_PRINT((ndo, "[|nflog]"));
126			return h_size;
127		}
128
129		if (tlv->tlv_type == NFULA_PAYLOAD) {
130			/*
131			 * This TLV's data is the packet payload.
132			 * Skip past the TLV header, and break out
133			 * of the loop so we print the packet data.
134			 */
135			p += sizeof(nflog_tlv_t);
136			h_size += sizeof(nflog_tlv_t);
137			length -= sizeof(nflog_tlv_t);
138			caplen -= sizeof(nflog_tlv_t);
139			break;
140		}
141
142		p += size;
143		h_size += size;
144		length -= size;
145		caplen -= size;
146	}
147
148	switch (hdr->nflog_family) {
149
150	case AF_INET:
151		ip_print(ndo, p, length);
152		break;
153
154#ifdef AF_INET6
155	case AF_INET6:
156		ip6_print(ndo, p, length);
157		break;
158#endif /* AF_INET6 */
159
160	default:
161		if (!ndo->ndo_eflag)
162			nflog_hdr_print(ndo, hdr,
163				length + sizeof(nflog_hdr_t));
164
165		if (!ndo->ndo_suppress_default_print)
166			ND_DEFAULTPRINT(p, caplen);
167		break;
168	}
169
170	return h_size;
171}
172
173#endif /* defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H) */
174