summaryrefslogtreecommitdiff
path: root/src/build.c
blob: 9c3687c4f6eab92ef37b3b7d4387e66005f12f2e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
/*
 * (C) 2006-2011 by Pablo Neira Ayuso <pablo@netfilter.org>
 * (C) 2011 by Vyatta Inc. <http://www.vyatta.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <string.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#include "network.h"
#include "conntrackd.h"

static inline void *
put_header(struct nethdr *n, int attr, size_t len)
{
	struct netattr *nta = NETHDR_TAIL(n);
	int total_size = NTA_ALIGN(NTA_LENGTH(len));
	int attr_size = NTA_LENGTH(len);
	n->len += total_size;
	nta->nta_attr = htons(attr);
	nta->nta_len = htons(attr_size);
	memset((unsigned char *)nta + attr_size, 0, total_size - attr_size);
	return NTA_DATA(nta);
}

static inline void
addattr(struct nethdr *n, int attr, const void *data, size_t len)
{
	void *ptr = put_header(n, attr, len);
	memcpy(ptr, data, len);
}

static inline void
ct_build_u8(const struct nf_conntrack *ct, int a, struct nethdr *n, int b)
{
	void *ptr = put_header(n, b, sizeof(uint8_t));
	memcpy(ptr, nfct_get_attr(ct, a), sizeof(uint8_t));
}

static inline void 
ct_build_u16(const struct nf_conntrack *ct, int a, struct nethdr *n, int b)
{
	uint16_t data = nfct_get_attr_u16(ct, a);
	data = htons(data);
	addattr(n, b, &data, sizeof(uint16_t));
}

static inline void 
ct_build_u32(const struct nf_conntrack *ct, int a, struct nethdr *n, int b)
{
	uint32_t data = nfct_get_attr_u32(ct, a);
	data = htonl(data);
	addattr(n, b, &data, sizeof(uint32_t));
}

static inline void 
ct_build_group(const struct nf_conntrack *ct, int a, struct nethdr *n, 
	      int b, int size)
{
	void *ptr = put_header(n, b, size);
	nfct_get_attr_grp(ct, a, ptr);
}

static inline void 
ct_build_natseqadj(const struct nf_conntrack *ct, struct nethdr *n)
{
	struct nta_attr_natseqadj data = {
		.orig_seq_correction_pos =
		htonl(nfct_get_attr_u32(ct, ATTR_ORIG_NAT_SEQ_CORRECTION_POS)),
		.orig_seq_offset_before = 
		htonl(nfct_get_attr_u32(ct, ATTR_ORIG_NAT_SEQ_OFFSET_BEFORE)),
		.orig_seq_offset_after =
		htonl(nfct_get_attr_u32(ct, ATTR_ORIG_NAT_SEQ_OFFSET_AFTER)),
		.repl_seq_correction_pos = 
		htonl(nfct_get_attr_u32(ct, ATTR_REPL_NAT_SEQ_CORRECTION_POS)),
		.repl_seq_offset_before =
		htonl(nfct_get_attr_u32(ct, ATTR_REPL_NAT_SEQ_OFFSET_BEFORE)),
		.repl_seq_offset_after = 
		htonl(nfct_get_attr_u32(ct, ATTR_REPL_NAT_SEQ_OFFSET_AFTER))
	};
	addattr(n, NTA_NAT_SEQ_ADJ, &data, sizeof(struct nta_attr_natseqadj));
}

static enum nf_conntrack_attr nat_type[] =
	{ ATTR_ORIG_NAT_SEQ_CORRECTION_POS, ATTR_ORIG_NAT_SEQ_OFFSET_BEFORE,
	  ATTR_ORIG_NAT_SEQ_OFFSET_AFTER, ATTR_REPL_NAT_SEQ_CORRECTION_POS,
	  ATTR_REPL_NAT_SEQ_OFFSET_BEFORE, ATTR_REPL_NAT_SEQ_OFFSET_AFTER };

static void build_l4proto_tcp(const struct nf_conntrack *ct, struct nethdr *n)
{
	ct_build_group(ct, ATTR_GRP_ORIG_PORT, n, NTA_PORT,
		      sizeof(struct nfct_attr_grp_port));

	if (!nfct_attr_is_set(ct, ATTR_TCP_STATE))
		return;

	ct_build_u8(ct, ATTR_TCP_STATE, n, NTA_TCP_STATE);
	if (CONFIG(sync).tcp_window_tracking) {
		ct_build_u8(ct, ATTR_TCP_WSCALE_ORIG, n, NTA_TCP_WSCALE_ORIG);
		ct_build_u8(ct, ATTR_TCP_WSCALE_REPL, n, NTA_TCP_WSCALE_REPL);
	}
}

static void build_l4proto_sctp(const struct nf_conntrack *ct, struct nethdr *n)
{
	ct_build_group(ct, ATTR_GRP_ORIG_PORT, n, NTA_PORT,
		      sizeof(struct nfct_attr_grp_port));

	if (!nfct_attr_is_set(ct, ATTR_SCTP_STATE))
		return;

	ct_build_u8(ct, ATTR_SCTP_STATE, n, NTA_SCTP_STATE);
	ct_build_u32(ct, ATTR_SCTP_VTAG_ORIG, n, NTA_SCTP_VTAG_ORIG);
	ct_build_u32(ct, ATTR_SCTP_VTAG_REPL, n, NTA_SCTP_VTAG_REPL);
}

static void build_l4proto_dccp(const struct nf_conntrack *ct, struct nethdr *n)
{
	ct_build_group(ct, ATTR_GRP_ORIG_PORT, n, NTA_PORT,
		      sizeof(struct nfct_attr_grp_port));

	if (!nfct_attr_is_set(ct, ATTR_DCCP_STATE))
		return;

	ct_build_u8(ct, ATTR_DCCP_STATE, n, NTA_DCCP_STATE);
	ct_build_u8(ct, ATTR_DCCP_ROLE, n, NTA_DCCP_ROLE);
}

static void build_l4proto_icmp(const struct nf_conntrack *ct, struct nethdr *n)
{
	ct_build_u8(ct, ATTR_ICMP_TYPE, n, NTA_ICMP_TYPE);
	ct_build_u8(ct, ATTR_ICMP_CODE, n, NTA_ICMP_CODE);
	ct_build_u16(ct, ATTR_ICMP_ID, n, NTA_ICMP_ID);
}

static void build_l4proto_udp(const struct nf_conntrack *ct, struct nethdr *n)
{
	ct_build_group(ct, ATTR_GRP_ORIG_PORT, n, NTA_PORT,
		      sizeof(struct nfct_attr_grp_port));
}

#ifndef IPPROTO_DCCP
#define IPPROTO_DCCP 33
#endif

static struct build_l4proto {
	void (*build)(const struct nf_conntrack *, struct nethdr *n);
} l4proto_fcn[IPPROTO_MAX] = {
	[IPPROTO_TCP]		= { .build = build_l4proto_tcp },
	[IPPROTO_SCTP]		= { .build = build_l4proto_sctp },
	[IPPROTO_DCCP]		= { .build = build_l4proto_dccp },
	[IPPROTO_ICMP]		= { .build = build_l4proto_icmp },
	[IPPROTO_ICMPV6]	= { .build = build_l4proto_icmp },
	[IPPROTO_UDP]		= { .build = build_l4proto_udp },
};

void ct2msg(const struct nf_conntrack *ct, struct nethdr *n)
{
	uint8_t l4proto = nfct_get_attr_u8(ct, ATTR_L4PROTO);

	if (nfct_attr_grp_is_set(ct, ATTR_GRP_ORIG_IPV4)) {
		ct_build_group(ct, ATTR_GRP_ORIG_IPV4, n, NTA_IPV4, 
			      sizeof(struct nfct_attr_grp_ipv4));
	} else if (nfct_attr_grp_is_set(ct, ATTR_GRP_ORIG_IPV6)) {
		ct_build_group(ct, ATTR_GRP_ORIG_IPV6, n, NTA_IPV6, 
			      sizeof(struct nfct_attr_grp_ipv6));
	}

	ct_build_u32(ct, ATTR_STATUS, n, NTA_STATUS); 
	ct_build_u8(ct, ATTR_L4PROTO, n, NTA_L4PROTO);

	if (l4proto_fcn[l4proto].build)
		l4proto_fcn[l4proto].build(ct, n);

	if (!CONFIG(commit_timeout) && nfct_attr_is_set(ct, ATTR_TIMEOUT))
		ct_build_u32(ct, ATTR_TIMEOUT, n, NTA_TIMEOUT);
	if (nfct_attr_is_set(ct, ATTR_MARK))
		ct_build_u32(ct, ATTR_MARK, n, NTA_MARK);

	/* setup the master conntrack */
	if (nfct_attr_grp_is_set(ct, ATTR_GRP_MASTER_IPV4)) {
		ct_build_group(ct, ATTR_GRP_MASTER_IPV4, n, NTA_MASTER_IPV4,
			      sizeof(struct nfct_attr_grp_ipv4));
		ct_build_u8(ct, ATTR_MASTER_L4PROTO, n, NTA_MASTER_L4PROTO);
		if (nfct_attr_grp_is_set(ct, ATTR_GRP_MASTER_PORT)) {
			ct_build_group(ct, ATTR_GRP_MASTER_PORT,
				      n, NTA_MASTER_PORT, 
				      sizeof(struct nfct_attr_grp_port));
		}
	} else if (nfct_attr_grp_is_set(ct, ATTR_GRP_MASTER_IPV6)) {
		ct_build_group(ct, ATTR_GRP_MASTER_IPV6, n, NTA_MASTER_IPV6,
			      sizeof(struct nfct_attr_grp_ipv6));
		ct_build_u8(ct, ATTR_MASTER_L4PROTO, n, NTA_MASTER_L4PROTO);
		if (nfct_attr_grp_is_set(ct, ATTR_GRP_MASTER_PORT)) {
			ct_build_group(ct, ATTR_GRP_MASTER_PORT,
				      n, NTA_MASTER_PORT,
				      sizeof(struct nfct_attr_grp_port));
		}
	}

	/*  NAT */
	if (nfct_getobjopt(ct, NFCT_GOPT_IS_SNAT))
		ct_build_u32(ct, ATTR_REPL_IPV4_DST, n, NTA_SNAT_IPV4);
	if (nfct_getobjopt(ct, NFCT_GOPT_IS_DNAT))
		ct_build_u32(ct, ATTR_REPL_IPV4_SRC, n, NTA_DNAT_IPV4);
	if (nfct_getobjopt(ct, NFCT_GOPT_IS_SPAT))
		ct_build_u16(ct, ATTR_REPL_PORT_DST, n, NTA_SPAT_PORT);
	if (nfct_getobjopt(ct, NFCT_GOPT_IS_DPAT))
		ct_build_u16(ct, ATTR_REPL_PORT_SRC, n, NTA_DPAT_PORT);

	/* NAT sequence adjustment */
	if (nfct_attr_is_set_array(ct, nat_type, 6))
		ct_build_natseqadj(ct, n);
}