xref: /freebsd/contrib/tcpdump/print-nflog.c (revision 63a938566d524836885917d95bd491aa4400b181)
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 
38 #if defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H)
39 #include <pcap/nflog.h>
40 
41 static const struct tok nflog_values[] = {
42 	{ AF_INET,		"IPv4" },
43 #ifdef AF_INET6
44 	{ AF_INET6,		"IPv6" },
45 #endif /*AF_INET6*/
46 	{ 0,			NULL }
47 };
48 
49 static inline void
50 nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
51 {
52 	ND_PRINT((ndo, "version %d, resource ID %d", hdr->nflog_version, ntohs(hdr->nflog_rid)));
53 
54 	if (!ndo->ndo_qflag) {
55 		ND_PRINT((ndo,", family %s (%d)",
56 						  tok2str(nflog_values, "Unknown",
57 								  hdr->nflog_family),
58 						  hdr->nflog_family));
59 		} else {
60 		ND_PRINT((ndo,", %s",
61 						  tok2str(nflog_values,
62 								  "Unknown NFLOG (0x%02x)",
63 								  hdr->nflog_family)));
64 		}
65 
66 	ND_PRINT((ndo, ", length %u: ", length));
67 }
68 
69 u_int
70 nflog_if_print(netdissect_options *ndo,
71 			   const struct pcap_pkthdr *h, const u_char *p)
72 {
73 	const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
74 	const nflog_tlv_t *tlv;
75 	uint16_t size;
76 	uint16_t h_size = sizeof(nflog_hdr_t);
77 	u_int caplen = h->caplen;
78 	u_int length = h->len;
79 
80 	if (caplen < (int) sizeof(nflog_hdr_t) || length < (int) sizeof(nflog_hdr_t)) {
81 		ND_PRINT((ndo, "[|nflog]"));
82 		return h_size;
83 	}
84 
85 	if (hdr->nflog_version != 0) {
86 		ND_PRINT((ndo, "version %u (unknown)", hdr->nflog_version));
87 		return h_size;
88 	}
89 
90 	if (ndo->ndo_eflag)
91 		nflog_hdr_print(ndo, hdr, length);
92 
93 	p += sizeof(nflog_hdr_t);
94 	length -= sizeof(nflog_hdr_t);
95 	caplen -= sizeof(nflog_hdr_t);
96 
97 	while (length > 0) {
98 		/* We have some data.  Do we have enough for the TLV header? */
99 		if (caplen < sizeof(nflog_tlv_t) || length < sizeof(nflog_tlv_t)) {
100 			/* No. */
101 			ND_PRINT((ndo, "[|nflog]"));
102 			return h_size;
103 		}
104 
105 		tlv = (const nflog_tlv_t *) p;
106 		size = tlv->tlv_length;
107 		if (size % 4 != 0)
108 			size += 4 - size % 4;
109 
110 		/* Is the TLV's length less than the minimum? */
111 		if (size < sizeof(nflog_tlv_t)) {
112 			/* Yes. Give up now. */
113 			ND_PRINT((ndo, "[|nflog]"));
114 			return h_size;
115 		}
116 
117 		/* Do we have enough data for the full TLV? */
118 		if (caplen < size || length < size) {
119 			/* No. */
120 			ND_PRINT((ndo, "[|nflog]"));
121 			return h_size;
122 		}
123 
124 		if (tlv->tlv_type == NFULA_PAYLOAD) {
125 			/*
126 			 * This TLV's data is the packet payload.
127 			 * Skip past the TLV header, and break out
128 			 * of the loop so we print the packet data.
129 			 */
130 			p += sizeof(nflog_tlv_t);
131 			h_size += sizeof(nflog_tlv_t);
132 			length -= sizeof(nflog_tlv_t);
133 			caplen -= sizeof(nflog_tlv_t);
134 			break;
135 		}
136 
137 		p += size;
138 		h_size += size;
139 		length -= size;
140 		caplen -= size;
141 	}
142 
143 	switch (hdr->nflog_family) {
144 
145 	case AF_INET:
146 		ip_print(ndo, p, length);
147 		break;
148 
149 #ifdef AF_INET6
150 	case AF_INET6:
151 		ip6_print(ndo, p, length);
152 		break;
153 #endif /* AF_INET6 */
154 
155 	default:
156 		if (!ndo->ndo_eflag)
157 			nflog_hdr_print(ndo, hdr,
158 				length + sizeof(nflog_hdr_t));
159 
160 		if (!ndo->ndo_suppress_default_print)
161 			ND_DEFAULTPRINT(p, caplen);
162 		break;
163 	}
164 
165 	return h_size;
166 }
167 
168 #endif /* defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H) */
169