1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
4 * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
5 * Copyright (c) 2012 Intel Corporation
6 */
7
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/skbuff.h>
11 #include <linux/ip.h>
12 #include <linux/string.h>
13 #include <linux/netlink.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter_ipv4.h>
16 #include <linux/netfilter/nfnetlink.h>
17 #include <linux/netfilter/nf_tables.h>
18 #include <net/netfilter/nf_conntrack.h>
19 #include <net/netfilter/nf_nat.h>
20 #include <net/netfilter/nf_tables.h>
21 #include <net/ip.h>
22
23 struct nft_nat {
24 u8 sreg_addr_min;
25 u8 sreg_addr_max;
26 u8 sreg_proto_min;
27 u8 sreg_proto_max;
28 enum nf_nat_manip_type type:8;
29 u8 family;
30 u16 flags;
31 };
32
nft_nat_setup_addr(struct nf_nat_range2 * range,const struct nft_regs * regs,const struct nft_nat * priv)33 static void nft_nat_setup_addr(struct nf_nat_range2 *range,
34 const struct nft_regs *regs,
35 const struct nft_nat *priv)
36 {
37 switch (priv->family) {
38 case AF_INET:
39 range->min_addr.ip = (__force __be32)
40 regs->data[priv->sreg_addr_min];
41 range->max_addr.ip = (__force __be32)
42 regs->data[priv->sreg_addr_max];
43 break;
44 case AF_INET6:
45 memcpy(range->min_addr.ip6, ®s->data[priv->sreg_addr_min],
46 sizeof(range->min_addr.ip6));
47 memcpy(range->max_addr.ip6, ®s->data[priv->sreg_addr_max],
48 sizeof(range->max_addr.ip6));
49 break;
50 }
51 }
52
nft_nat_setup_proto(struct nf_nat_range2 * range,const struct nft_regs * regs,const struct nft_nat * priv)53 static void nft_nat_setup_proto(struct nf_nat_range2 *range,
54 const struct nft_regs *regs,
55 const struct nft_nat *priv)
56 {
57 range->min_proto.all = (__force __be16)
58 nft_reg_load16(®s->data[priv->sreg_proto_min]);
59 range->max_proto.all = (__force __be16)
60 nft_reg_load16(®s->data[priv->sreg_proto_max]);
61 }
62
nft_nat_setup_netmap(struct nf_nat_range2 * range,const struct nft_pktinfo * pkt,const struct nft_nat * priv)63 static void nft_nat_setup_netmap(struct nf_nat_range2 *range,
64 const struct nft_pktinfo *pkt,
65 const struct nft_nat *priv)
66 {
67 struct sk_buff *skb = pkt->skb;
68 union nf_inet_addr new_addr;
69 __be32 netmask;
70 int i, len = 0;
71
72 switch (priv->type) {
73 case NFT_NAT_SNAT:
74 if (nft_pf(pkt) == NFPROTO_IPV4) {
75 new_addr.ip = ip_hdr(skb)->saddr;
76 len = sizeof(struct in_addr);
77 } else {
78 new_addr.in6 = ipv6_hdr(skb)->saddr;
79 len = sizeof(struct in6_addr);
80 }
81 break;
82 case NFT_NAT_DNAT:
83 if (nft_pf(pkt) == NFPROTO_IPV4) {
84 new_addr.ip = ip_hdr(skb)->daddr;
85 len = sizeof(struct in_addr);
86 } else {
87 new_addr.in6 = ipv6_hdr(skb)->daddr;
88 len = sizeof(struct in6_addr);
89 }
90 break;
91 }
92
93 for (i = 0; i < len / sizeof(__be32); i++) {
94 netmask = ~(range->min_addr.ip6[i] ^ range->max_addr.ip6[i]);
95 new_addr.ip6[i] &= ~netmask;
96 new_addr.ip6[i] |= range->min_addr.ip6[i] & netmask;
97 }
98
99 range->min_addr = new_addr;
100 range->max_addr = new_addr;
101 }
102
nft_nat_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)103 static void nft_nat_eval(const struct nft_expr *expr,
104 struct nft_regs *regs,
105 const struct nft_pktinfo *pkt)
106 {
107 const struct nft_nat *priv = nft_expr_priv(expr);
108 enum ip_conntrack_info ctinfo;
109 struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo);
110 struct nf_nat_range2 range;
111
112 memset(&range, 0, sizeof(range));
113
114 if (priv->sreg_addr_min) {
115 nft_nat_setup_addr(&range, regs, priv);
116 if (priv->flags & NF_NAT_RANGE_NETMAP)
117 nft_nat_setup_netmap(&range, pkt, priv);
118 }
119
120 if (priv->sreg_proto_min)
121 nft_nat_setup_proto(&range, regs, priv);
122
123 range.flags = priv->flags;
124
125 regs->verdict.code = nf_nat_setup_info(ct, &range, priv->type);
126 }
127
128 static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = {
129 [NFTA_NAT_TYPE] = { .type = NLA_U32 },
130 [NFTA_NAT_FAMILY] = { .type = NLA_U32 },
131 [NFTA_NAT_REG_ADDR_MIN] = { .type = NLA_U32 },
132 [NFTA_NAT_REG_ADDR_MAX] = { .type = NLA_U32 },
133 [NFTA_NAT_REG_PROTO_MIN] = { .type = NLA_U32 },
134 [NFTA_NAT_REG_PROTO_MAX] = { .type = NLA_U32 },
135 [NFTA_NAT_FLAGS] =
136 NLA_POLICY_MASK(NLA_BE32, NF_NAT_RANGE_MASK),
137 };
138
nft_nat_validate(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nft_data ** data)139 static int nft_nat_validate(const struct nft_ctx *ctx,
140 const struct nft_expr *expr,
141 const struct nft_data **data)
142 {
143 struct nft_nat *priv = nft_expr_priv(expr);
144 int err;
145
146 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
147 if (err < 0)
148 return err;
149
150 switch (priv->type) {
151 case NFT_NAT_SNAT:
152 err = nft_chain_validate_hooks(ctx->chain,
153 (1 << NF_INET_POST_ROUTING) |
154 (1 << NF_INET_LOCAL_IN));
155 break;
156 case NFT_NAT_DNAT:
157 err = nft_chain_validate_hooks(ctx->chain,
158 (1 << NF_INET_PRE_ROUTING) |
159 (1 << NF_INET_LOCAL_OUT));
160 break;
161 }
162
163 return err;
164 }
165
nft_nat_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])166 static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
167 const struct nlattr * const tb[])
168 {
169 struct nft_nat *priv = nft_expr_priv(expr);
170 unsigned int alen, plen;
171 u32 family;
172 int err;
173
174 if (tb[NFTA_NAT_TYPE] == NULL ||
175 (tb[NFTA_NAT_REG_ADDR_MIN] == NULL &&
176 tb[NFTA_NAT_REG_PROTO_MIN] == NULL))
177 return -EINVAL;
178
179 switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
180 case NFT_NAT_SNAT:
181 priv->type = NF_NAT_MANIP_SRC;
182 break;
183 case NFT_NAT_DNAT:
184 priv->type = NF_NAT_MANIP_DST;
185 break;
186 default:
187 return -EOPNOTSUPP;
188 }
189
190 if (tb[NFTA_NAT_FAMILY] == NULL)
191 return -EINVAL;
192
193 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
194 if (ctx->family != NFPROTO_INET && ctx->family != family)
195 return -EOPNOTSUPP;
196
197 switch (family) {
198 case NFPROTO_IPV4:
199 alen = sizeof_field(struct nf_nat_range, min_addr.ip);
200 break;
201 case NFPROTO_IPV6:
202 alen = sizeof_field(struct nf_nat_range, min_addr.ip6);
203 break;
204 default:
205 if (tb[NFTA_NAT_REG_ADDR_MIN])
206 return -EAFNOSUPPORT;
207 break;
208 }
209 priv->family = family;
210
211 if (tb[NFTA_NAT_REG_ADDR_MIN]) {
212 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN],
213 &priv->sreg_addr_min, alen);
214 if (err < 0)
215 return err;
216
217 if (tb[NFTA_NAT_REG_ADDR_MAX]) {
218 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX],
219 &priv->sreg_addr_max,
220 alen);
221 if (err < 0)
222 return err;
223 } else {
224 priv->sreg_addr_max = priv->sreg_addr_min;
225 }
226
227 priv->flags |= NF_NAT_RANGE_MAP_IPS;
228 }
229
230 plen = sizeof_field(struct nf_nat_range, min_proto.all);
231 if (tb[NFTA_NAT_REG_PROTO_MIN]) {
232 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN],
233 &priv->sreg_proto_min, plen);
234 if (err < 0)
235 return err;
236
237 if (tb[NFTA_NAT_REG_PROTO_MAX]) {
238 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX],
239 &priv->sreg_proto_max,
240 plen);
241 if (err < 0)
242 return err;
243 } else {
244 priv->sreg_proto_max = priv->sreg_proto_min;
245 }
246
247 priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
248 }
249
250 if (tb[NFTA_NAT_FLAGS])
251 priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS]));
252
253 return nf_ct_netns_get(ctx->net, family);
254 }
255
nft_nat_dump(struct sk_buff * skb,const struct nft_expr * expr,bool reset)256 static int nft_nat_dump(struct sk_buff *skb,
257 const struct nft_expr *expr, bool reset)
258 {
259 const struct nft_nat *priv = nft_expr_priv(expr);
260
261 switch (priv->type) {
262 case NF_NAT_MANIP_SRC:
263 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
264 goto nla_put_failure;
265 break;
266 case NF_NAT_MANIP_DST:
267 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
268 goto nla_put_failure;
269 break;
270 }
271
272 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
273 goto nla_put_failure;
274
275 if (priv->sreg_addr_min) {
276 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN,
277 priv->sreg_addr_min) ||
278 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX,
279 priv->sreg_addr_max))
280 goto nla_put_failure;
281 }
282
283 if (priv->sreg_proto_min) {
284 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN,
285 priv->sreg_proto_min) ||
286 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX,
287 priv->sreg_proto_max))
288 goto nla_put_failure;
289 }
290
291 if (priv->flags != 0) {
292 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags)))
293 goto nla_put_failure;
294 }
295
296 return 0;
297
298 nla_put_failure:
299 return -1;
300 }
301
302 static void
nft_nat_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)303 nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
304 {
305 const struct nft_nat *priv = nft_expr_priv(expr);
306
307 nf_ct_netns_put(ctx->net, priv->family);
308 }
309
310 static struct nft_expr_type nft_nat_type;
311 static const struct nft_expr_ops nft_nat_ops = {
312 .type = &nft_nat_type,
313 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
314 .eval = nft_nat_eval,
315 .init = nft_nat_init,
316 .destroy = nft_nat_destroy,
317 .dump = nft_nat_dump,
318 .validate = nft_nat_validate,
319 .reduce = NFT_REDUCE_READONLY,
320 };
321
322 static struct nft_expr_type nft_nat_type __read_mostly = {
323 .name = "nat",
324 .ops = &nft_nat_ops,
325 .policy = nft_nat_policy,
326 .maxattr = NFTA_NAT_MAX,
327 .owner = THIS_MODULE,
328 };
329
330 #ifdef CONFIG_NF_TABLES_INET
nft_nat_inet_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)331 static void nft_nat_inet_eval(const struct nft_expr *expr,
332 struct nft_regs *regs,
333 const struct nft_pktinfo *pkt)
334 {
335 const struct nft_nat *priv = nft_expr_priv(expr);
336
337 if (priv->family == nft_pf(pkt) ||
338 priv->family == NFPROTO_INET)
339 nft_nat_eval(expr, regs, pkt);
340 }
341
342 static const struct nft_expr_ops nft_nat_inet_ops = {
343 .type = &nft_nat_type,
344 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
345 .eval = nft_nat_inet_eval,
346 .init = nft_nat_init,
347 .destroy = nft_nat_destroy,
348 .dump = nft_nat_dump,
349 .validate = nft_nat_validate,
350 .reduce = NFT_REDUCE_READONLY,
351 };
352
353 static struct nft_expr_type nft_inet_nat_type __read_mostly = {
354 .name = "nat",
355 .family = NFPROTO_INET,
356 .ops = &nft_nat_inet_ops,
357 .policy = nft_nat_policy,
358 .maxattr = NFTA_NAT_MAX,
359 .owner = THIS_MODULE,
360 };
361
nft_nat_inet_module_init(void)362 static int nft_nat_inet_module_init(void)
363 {
364 return nft_register_expr(&nft_inet_nat_type);
365 }
366
nft_nat_inet_module_exit(void)367 static void nft_nat_inet_module_exit(void)
368 {
369 nft_unregister_expr(&nft_inet_nat_type);
370 }
371 #else
nft_nat_inet_module_init(void)372 static int nft_nat_inet_module_init(void) { return 0; }
nft_nat_inet_module_exit(void)373 static void nft_nat_inet_module_exit(void) { }
374 #endif
375
nft_nat_module_init(void)376 static int __init nft_nat_module_init(void)
377 {
378 int ret = nft_nat_inet_module_init();
379
380 if (ret)
381 return ret;
382
383 ret = nft_register_expr(&nft_nat_type);
384 if (ret)
385 nft_nat_inet_module_exit();
386
387 return ret;
388 }
389
nft_nat_module_exit(void)390 static void __exit nft_nat_module_exit(void)
391 {
392 nft_nat_inet_module_exit();
393 nft_unregister_expr(&nft_nat_type);
394 }
395
396 module_init(nft_nat_module_init);
397 module_exit(nft_nat_module_exit);
398
399 MODULE_LICENSE("GPL");
400 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
401 MODULE_ALIAS_NFT_EXPR("nat");
402 MODULE_DESCRIPTION("Network Address Translation support");
403
