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] = { .type = NLA_U32 },
136 };
137
nft_nat_validate(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nft_data ** data)138 static int nft_nat_validate(const struct nft_ctx *ctx,
139 const struct nft_expr *expr,
140 const struct nft_data **data)
141 {
142 struct nft_nat *priv = nft_expr_priv(expr);
143 int err;
144
145 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
146 if (err < 0)
147 return err;
148
149 switch (priv->type) {
150 case NFT_NAT_SNAT:
151 err = nft_chain_validate_hooks(ctx->chain,
152 (1 << NF_INET_POST_ROUTING) |
153 (1 << NF_INET_LOCAL_IN));
154 break;
155 case NFT_NAT_DNAT:
156 err = nft_chain_validate_hooks(ctx->chain,
157 (1 << NF_INET_PRE_ROUTING) |
158 (1 << NF_INET_LOCAL_OUT));
159 break;
160 }
161
162 return err;
163 }
164
nft_nat_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])165 static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
166 const struct nlattr * const tb[])
167 {
168 struct nft_nat *priv = nft_expr_priv(expr);
169 unsigned int alen, plen;
170 u32 family;
171 int err;
172
173 if (tb[NFTA_NAT_TYPE] == NULL ||
174 (tb[NFTA_NAT_REG_ADDR_MIN] == NULL &&
175 tb[NFTA_NAT_REG_PROTO_MIN] == NULL))
176 return -EINVAL;
177
178 switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
179 case NFT_NAT_SNAT:
180 priv->type = NF_NAT_MANIP_SRC;
181 break;
182 case NFT_NAT_DNAT:
183 priv->type = NF_NAT_MANIP_DST;
184 break;
185 default:
186 return -EOPNOTSUPP;
187 }
188
189 if (tb[NFTA_NAT_FAMILY] == NULL)
190 return -EINVAL;
191
192 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
193 if (ctx->family != NFPROTO_INET && ctx->family != family)
194 return -EOPNOTSUPP;
195
196 switch (family) {
197 case NFPROTO_IPV4:
198 alen = sizeof_field(struct nf_nat_range, min_addr.ip);
199 break;
200 case NFPROTO_IPV6:
201 alen = sizeof_field(struct nf_nat_range, min_addr.ip6);
202 break;
203 default:
204 if (tb[NFTA_NAT_REG_ADDR_MIN])
205 return -EAFNOSUPPORT;
206 break;
207 }
208 priv->family = family;
209
210 if (tb[NFTA_NAT_REG_ADDR_MIN]) {
211 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN],
212 &priv->sreg_addr_min, alen);
213 if (err < 0)
214 return err;
215
216 if (tb[NFTA_NAT_REG_ADDR_MAX]) {
217 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX],
218 &priv->sreg_addr_max,
219 alen);
220 if (err < 0)
221 return err;
222 } else {
223 priv->sreg_addr_max = priv->sreg_addr_min;
224 }
225
226 priv->flags |= NF_NAT_RANGE_MAP_IPS;
227 }
228
229 plen = sizeof_field(struct nf_nat_range, min_addr.all);
230 if (tb[NFTA_NAT_REG_PROTO_MIN]) {
231 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN],
232 &priv->sreg_proto_min, plen);
233 if (err < 0)
234 return err;
235
236 if (tb[NFTA_NAT_REG_PROTO_MAX]) {
237 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX],
238 &priv->sreg_proto_max,
239 plen);
240 if (err < 0)
241 return err;
242 } else {
243 priv->sreg_proto_max = priv->sreg_proto_min;
244 }
245
246 priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
247 }
248
249 if (tb[NFTA_NAT_FLAGS]) {
250 priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS]));
251 if (priv->flags & ~NF_NAT_RANGE_MASK)
252 return -EOPNOTSUPP;
253 }
254
255 return nf_ct_netns_get(ctx->net, family);
256 }
257
nft_nat_dump(struct sk_buff * skb,const struct nft_expr * expr)258 static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
259 {
260 const struct nft_nat *priv = nft_expr_priv(expr);
261
262 switch (priv->type) {
263 case NF_NAT_MANIP_SRC:
264 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
265 goto nla_put_failure;
266 break;
267 case NF_NAT_MANIP_DST:
268 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
269 goto nla_put_failure;
270 break;
271 }
272
273 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
274 goto nla_put_failure;
275
276 if (priv->sreg_addr_min) {
277 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN,
278 priv->sreg_addr_min) ||
279 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX,
280 priv->sreg_addr_max))
281 goto nla_put_failure;
282 }
283
284 if (priv->sreg_proto_min) {
285 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN,
286 priv->sreg_proto_min) ||
287 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX,
288 priv->sreg_proto_max))
289 goto nla_put_failure;
290 }
291
292 if (priv->flags != 0) {
293 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags)))
294 goto nla_put_failure;
295 }
296
297 return 0;
298
299 nla_put_failure:
300 return -1;
301 }
302
303 static void
nft_nat_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)304 nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
305 {
306 const struct nft_nat *priv = nft_expr_priv(expr);
307
308 nf_ct_netns_put(ctx->net, priv->family);
309 }
310
311 static struct nft_expr_type nft_nat_type;
312 static const struct nft_expr_ops nft_nat_ops = {
313 .type = &nft_nat_type,
314 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
315 .eval = nft_nat_eval,
316 .init = nft_nat_init,
317 .destroy = nft_nat_destroy,
318 .dump = nft_nat_dump,
319 .validate = nft_nat_validate,
320 .reduce = NFT_REDUCE_READONLY,
321 };
322
323 static struct nft_expr_type nft_nat_type __read_mostly = {
324 .name = "nat",
325 .ops = &nft_nat_ops,
326 .policy = nft_nat_policy,
327 .maxattr = NFTA_NAT_MAX,
328 .owner = THIS_MODULE,
329 };
330
331 #ifdef CONFIG_NF_TABLES_INET
nft_nat_inet_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)332 static void nft_nat_inet_eval(const struct nft_expr *expr,
333 struct nft_regs *regs,
334 const struct nft_pktinfo *pkt)
335 {
336 const struct nft_nat *priv = nft_expr_priv(expr);
337
338 if (priv->family == nft_pf(pkt) ||
339 priv->family == NFPROTO_INET)
340 nft_nat_eval(expr, regs, pkt);
341 }
342
343 static const struct nft_expr_ops nft_nat_inet_ops = {
344 .type = &nft_nat_type,
345 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
346 .eval = nft_nat_inet_eval,
347 .init = nft_nat_init,
348 .destroy = nft_nat_destroy,
349 .dump = nft_nat_dump,
350 .validate = nft_nat_validate,
351 .reduce = NFT_REDUCE_READONLY,
352 };
353
354 static struct nft_expr_type nft_inet_nat_type __read_mostly = {
355 .name = "nat",
356 .family = NFPROTO_INET,
357 .ops = &nft_nat_inet_ops,
358 .policy = nft_nat_policy,
359 .maxattr = NFTA_NAT_MAX,
360 .owner = THIS_MODULE,
361 };
362
nft_nat_inet_module_init(void)363 static int nft_nat_inet_module_init(void)
364 {
365 return nft_register_expr(&nft_inet_nat_type);
366 }
367
nft_nat_inet_module_exit(void)368 static void nft_nat_inet_module_exit(void)
369 {
370 nft_unregister_expr(&nft_inet_nat_type);
371 }
372 #else
nft_nat_inet_module_init(void)373 static int nft_nat_inet_module_init(void) { return 0; }
nft_nat_inet_module_exit(void)374 static void nft_nat_inet_module_exit(void) { }
375 #endif
376
nft_nat_module_init(void)377 static int __init nft_nat_module_init(void)
378 {
379 int ret = nft_nat_inet_module_init();
380
381 if (ret)
382 return ret;
383
384 ret = nft_register_expr(&nft_nat_type);
385 if (ret)
386 nft_nat_inet_module_exit();
387
388 return ret;
389 }
390
nft_nat_module_exit(void)391 static void __exit nft_nat_module_exit(void)
392 {
393 nft_nat_inet_module_exit();
394 nft_unregister_expr(&nft_nat_type);
395 }
396
397 module_init(nft_nat_module_init);
398 module_exit(nft_nat_module_exit);
399
400 MODULE_LICENSE("GPL");
401 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
402 MODULE_ALIAS_NFT_EXPR("nat");
403 MODULE_DESCRIPTION("Network Address Translation support");
404
