libnftnl 1.2.8
nat.c
1/*
2 * (C) 2012-2014 Pablo Neira Ayuso <pablo@netfilter.org>
3 * (C) 2012 Intel Corporation
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published
7 * by the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * Authors:
11 * Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
12 */
13
14#include "internal.h"
15
16#include <stdio.h>
17#include <stdint.h>
18#include <limits.h>
19#include <string.h>
20#include <errno.h>
21#include <arpa/inet.h>
22#include <libmnl/libmnl.h>
23#include <linux/netfilter/nf_tables.h>
24#include <libnftnl/expr.h>
25#include <libnftnl/rule.h>
26
28 enum nft_registers sreg_addr_min;
29 enum nft_registers sreg_addr_max;
30 enum nft_registers sreg_proto_min;
31 enum nft_registers sreg_proto_max;
32 int family;
33 enum nft_nat_types type;
34 uint32_t flags;
35};
36
37static int
38nftnl_expr_nat_set(struct nftnl_expr *e, uint16_t type,
39 const void *data, uint32_t data_len)
40{
41 struct nftnl_expr_nat *nat = nftnl_expr_data(e);
42
43 switch(type) {
44 case NFTNL_EXPR_NAT_TYPE:
45 memcpy(&nat->type, data, data_len);
46 break;
47 case NFTNL_EXPR_NAT_FAMILY:
48 memcpy(&nat->family, data, data_len);
49 break;
50 case NFTNL_EXPR_NAT_REG_ADDR_MIN:
51 memcpy(&nat->sreg_addr_min, data, data_len);
52 break;
53 case NFTNL_EXPR_NAT_REG_ADDR_MAX:
54 memcpy(&nat->sreg_addr_max, data, data_len);
55 break;
56 case NFTNL_EXPR_NAT_REG_PROTO_MIN:
57 memcpy(&nat->sreg_proto_min, data, data_len);
58 break;
59 case NFTNL_EXPR_NAT_REG_PROTO_MAX:
60 memcpy(&nat->sreg_proto_max, data, data_len);
61 break;
62 case NFTNL_EXPR_NAT_FLAGS:
63 memcpy(&nat->flags, data, data_len);
64 break;
65 }
66
67 return 0;
68}
69
70static const void *
71nftnl_expr_nat_get(const struct nftnl_expr *e, uint16_t type,
72 uint32_t *data_len)
73{
74 struct nftnl_expr_nat *nat = nftnl_expr_data(e);
75
76 switch(type) {
77 case NFTNL_EXPR_NAT_TYPE:
78 *data_len = sizeof(nat->type);
79 return &nat->type;
80 case NFTNL_EXPR_NAT_FAMILY:
81 *data_len = sizeof(nat->family);
82 return &nat->family;
83 case NFTNL_EXPR_NAT_REG_ADDR_MIN:
84 *data_len = sizeof(nat->sreg_addr_min);
85 return &nat->sreg_addr_min;
86 case NFTNL_EXPR_NAT_REG_ADDR_MAX:
87 *data_len = sizeof(nat->sreg_addr_max);
88 return &nat->sreg_addr_max;
89 case NFTNL_EXPR_NAT_REG_PROTO_MIN:
90 *data_len = sizeof(nat->sreg_proto_min);
91 return &nat->sreg_proto_min;
92 case NFTNL_EXPR_NAT_REG_PROTO_MAX:
93 *data_len = sizeof(nat->sreg_proto_max);
94 return &nat->sreg_proto_max;
95 case NFTNL_EXPR_NAT_FLAGS:
96 *data_len = sizeof(nat->flags);
97 return &nat->flags;
98 }
99 return NULL;
100}
101
102static int nftnl_expr_nat_cb(const struct nlattr *attr, void *data)
103{
104 const struct nlattr **tb = data;
105 int type = mnl_attr_get_type(attr);
106
107 if (mnl_attr_type_valid(attr, NFTA_NAT_MAX) < 0)
108 return MNL_CB_OK;
109
110 switch(type) {
111 case NFTA_NAT_TYPE:
112 case NFTA_NAT_FAMILY:
113 case NFTA_NAT_REG_ADDR_MIN:
114 case NFTA_NAT_REG_ADDR_MAX:
115 case NFTA_NAT_REG_PROTO_MIN:
116 case NFTA_NAT_REG_PROTO_MAX:
117 case NFTA_NAT_FLAGS:
118 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
119 abi_breakage();
120 break;
121 }
122
123 tb[type] = attr;
124 return MNL_CB_OK;
125}
126
127static int
128nftnl_expr_nat_parse(struct nftnl_expr *e, struct nlattr *attr)
129{
130 struct nftnl_expr_nat *nat = nftnl_expr_data(e);
131 struct nlattr *tb[NFTA_NAT_MAX+1] = {};
132
133 if (mnl_attr_parse_nested(attr, nftnl_expr_nat_cb, tb) < 0)
134 return -1;
135
136 if (tb[NFTA_NAT_TYPE]) {
137 nat->type = ntohl(mnl_attr_get_u32(tb[NFTA_NAT_TYPE]));
138 e->flags |= (1 << NFTNL_EXPR_NAT_TYPE);
139 }
140 if (tb[NFTA_NAT_FAMILY]) {
141 nat->family = ntohl(mnl_attr_get_u32(tb[NFTA_NAT_FAMILY]));
142 e->flags |= (1 << NFTNL_EXPR_NAT_FAMILY);
143 }
144 if (tb[NFTA_NAT_REG_ADDR_MIN]) {
145 nat->sreg_addr_min =
146 ntohl(mnl_attr_get_u32(tb[NFTA_NAT_REG_ADDR_MIN]));
147 e->flags |= (1 << NFTNL_EXPR_NAT_REG_ADDR_MIN);
148 }
149 if (tb[NFTA_NAT_REG_ADDR_MAX]) {
150 nat->sreg_addr_max =
151 ntohl(mnl_attr_get_u32(tb[NFTA_NAT_REG_ADDR_MAX]));
152 e->flags |= (1 << NFTNL_EXPR_NAT_REG_ADDR_MAX);
153 }
154 if (tb[NFTA_NAT_REG_PROTO_MIN]) {
155 nat->sreg_proto_min =
156 ntohl(mnl_attr_get_u32(tb[NFTA_NAT_REG_PROTO_MIN]));
157 e->flags |= (1 << NFTNL_EXPR_NAT_REG_PROTO_MIN);
158 }
159 if (tb[NFTA_NAT_REG_PROTO_MAX]) {
160 nat->sreg_proto_max =
161 ntohl(mnl_attr_get_u32(tb[NFTA_NAT_REG_PROTO_MAX]));
162 e->flags |= (1 << NFTNL_EXPR_NAT_REG_PROTO_MAX);
163 }
164 if (tb[NFTA_NAT_FLAGS]) {
165 nat->flags = ntohl(mnl_attr_get_u32(tb[NFTA_NAT_FLAGS]));
166 e->flags |= (1 << NFTNL_EXPR_NAT_FLAGS);
167 }
168
169 return 0;
170}
171
172static void
173nftnl_expr_nat_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
174{
175 struct nftnl_expr_nat *nat = nftnl_expr_data(e);
176
177 if (e->flags & (1 << NFTNL_EXPR_NAT_TYPE))
178 mnl_attr_put_u32(nlh, NFTA_NAT_TYPE, htonl(nat->type));
179 if (e->flags & (1 << NFTNL_EXPR_NAT_FAMILY))
180 mnl_attr_put_u32(nlh, NFTA_NAT_FAMILY, htonl(nat->family));
181 if (e->flags & (1 << NFTNL_EXPR_NAT_REG_ADDR_MIN))
182 mnl_attr_put_u32(nlh, NFTA_NAT_REG_ADDR_MIN,
183 htonl(nat->sreg_addr_min));
184 if (e->flags & (1 << NFTNL_EXPR_NAT_REG_ADDR_MAX))
185 mnl_attr_put_u32(nlh, NFTA_NAT_REG_ADDR_MAX,
186 htonl(nat->sreg_addr_max));
187 if (e->flags & (1 << NFTNL_EXPR_NAT_REG_PROTO_MIN))
188 mnl_attr_put_u32(nlh, NFTA_NAT_REG_PROTO_MIN,
189 htonl(nat->sreg_proto_min));
190 if (e->flags & (1 << NFTNL_EXPR_NAT_REG_PROTO_MAX))
191 mnl_attr_put_u32(nlh, NFTA_NAT_REG_PROTO_MAX,
192 htonl(nat->sreg_proto_max));
193 if (e->flags & (1 << NFTNL_EXPR_NAT_FLAGS))
194 mnl_attr_put_u32(nlh, NFTA_NAT_FLAGS, htonl(nat->flags));
195}
196
197static inline const char *nat2str(uint16_t nat)
198{
199 switch (nat) {
200 case NFT_NAT_SNAT:
201 return "snat";
202 case NFT_NAT_DNAT:
203 return "dnat";
204 default:
205 return "unknown";
206 }
207}
208
209static inline int nftnl_str2nat(const char *nat)
210{
211 if (strcmp(nat, "snat") == 0)
212 return NFT_NAT_SNAT;
213 else if (strcmp(nat, "dnat") == 0)
214 return NFT_NAT_DNAT;
215 else {
216 errno = EINVAL;
217 return -1;
218 }
219}
220
221static int
222nftnl_expr_nat_snprintf(char *buf, size_t remain,
223 uint32_t flags, const struct nftnl_expr *e)
224{
225 struct nftnl_expr_nat *nat = nftnl_expr_data(e);
226 int offset = 0, ret = 0;
227
228 ret = snprintf(buf, remain, "%s ", nat2str(nat->type));
229 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
230
231 ret = snprintf(buf + offset, remain, "%s ",
232 nftnl_family2str(nat->family));
233 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
234
235 if (e->flags & (1 << NFTNL_EXPR_NAT_REG_ADDR_MIN)) {
236 ret = snprintf(buf + offset, remain,
237 "addr_min reg %u ", nat->sreg_addr_min);
238 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
239 }
240
241 if (e->flags & (1 << NFTNL_EXPR_NAT_REG_ADDR_MAX)) {
242 ret = snprintf(buf + offset, remain,
243 "addr_max reg %u ", nat->sreg_addr_max);
244 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
245 }
246
247 if (e->flags & (1 << NFTNL_EXPR_NAT_REG_PROTO_MIN)) {
248 ret = snprintf(buf + offset, remain,
249 "proto_min reg %u ", nat->sreg_proto_min);
250 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
251 }
252
253 if (e->flags & (1 << NFTNL_EXPR_NAT_REG_PROTO_MAX)) {
254 ret = snprintf(buf + offset, remain,
255 "proto_max reg %u ", nat->sreg_proto_max);
256 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
257 }
258
259 if (e->flags & (1 << NFTNL_EXPR_NAT_FLAGS)) {
260 ret = snprintf(buf + offset, remain, "flags 0x%x ", nat->flags);
261 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
262 }
263
264 return offset;
265}
266
267static struct attr_policy nat_attr_policy[__NFTNL_EXPR_NAT_MAX] = {
268 [NFTNL_EXPR_NAT_TYPE] = { .maxlen = sizeof(uint32_t) },
269 [NFTNL_EXPR_NAT_FAMILY] = { .maxlen = sizeof(uint32_t) },
270 [NFTNL_EXPR_NAT_REG_ADDR_MIN] = { .maxlen = sizeof(uint32_t) },
271 [NFTNL_EXPR_NAT_REG_ADDR_MAX] = { .maxlen = sizeof(uint32_t) },
272 [NFTNL_EXPR_NAT_REG_PROTO_MIN] = { .maxlen = sizeof(uint32_t) },
273 [NFTNL_EXPR_NAT_REG_PROTO_MAX] = { .maxlen = sizeof(uint32_t) },
274 [NFTNL_EXPR_NAT_FLAGS] = { .maxlen = sizeof(uint32_t) },
275};
276
277struct expr_ops expr_ops_nat = {
278 .name = "nat",
279 .alloc_len = sizeof(struct nftnl_expr_nat),
280 .nftnl_max_attr = __NFTNL_EXPR_NAT_MAX - 1,
281 .attr_policy = nat_attr_policy,
282 .set = nftnl_expr_nat_set,
283 .get = nftnl_expr_nat_get,
284 .parse = nftnl_expr_nat_parse,
285 .build = nftnl_expr_nat_build,
286 .output = nftnl_expr_nat_snprintf,
287};