print-nflog.c revision 1.1 
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#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include <tcpdump-stdinc.h>
33
34#include <stdio.h>
35#include <pcap.h>
36
37#include "netdissect.h"
38#include "interface.h"
39
40#include "nflog.h"
41
42#ifdef DLT_NFLOG
43
44#define NFULA_PAYLOAD 9
45
46static const struct tok nflog_values[] = {
47	{ AF_INET,		"IPv4" },
48	{ AF_INET6,		"IPv6" },
49	{ 0,				NULL }
50};
51
52static inline void
53nflog_hdr_print(struct 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(struct 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	u_int16_t size;
79	u_int16_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	length -= sizeof(nflog_hdr_t);
97	caplen -= sizeof(nflog_hdr_t);
98	p += sizeof(nflog_hdr_t);
99
100	do {
101		tlv = (const nflog_tlv_t *) p;
102		size = tlv->tlv_length;
103
104		if (size % 4 != 0)
105			size += 4 - size % 4;
106
107		h_size = h_size + size;
108
109		/* wrong size of the packet */
110		if (size > length || size == 0)
111			return h_size;
112
113		p += size;
114		length = length - size;
115		caplen = caplen - size;
116
117	} while (tlv->tlv_type != NFULA_PAYLOAD);
118
119	/* dont skip payload just tlv length and type */
120	p = p - size + 4;
121	length += size - 4;
122	caplen += size - 4;
123	h_size -= length;
124
125	switch (hdr->nflog_family) {
126
127	case AF_INET:
128			ip_print(ndo, p, length);
129		break;
130
131#ifdef INET6
132	case AF_INET6:
133		ip6_print(ndo, p, length);
134		break;
135#endif /*INET6*/
136
137	default:
138		if (!ndo->ndo_eflag)
139			nflog_hdr_print(ndo, hdr,
140				length + sizeof(nflog_hdr_t));
141
142		if (!ndo->ndo_suppress_default_print)
143			ndo->ndo_default_print(ndo, p, caplen);
144		break;
145	}
146
147	return h_size;
148}
149
150#endif /* DLT_NFLOG */
151