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 if (ctx->family != NFPROTO_IPV4 &&
147 ctx->family != NFPROTO_IPV6 &&
148 ctx->family != NFPROTO_INET)
149 return -EOPNOTSUPP;
150
151 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
152 if (err < 0)
153 return err;
154
155 switch (priv->type) {
156 case NFT_NAT_SNAT:
157 err = nft_chain_validate_hooks(ctx->chain,
158 (1 << NF_INET_POST_ROUTING) |
159 (1 << NF_INET_LOCAL_IN));
160 break;
161 case NFT_NAT_DNAT:
162 err = nft_chain_validate_hooks(ctx->chain,
163 (1 << NF_INET_PRE_ROUTING) |
164 (1 << NF_INET_LOCAL_OUT));
165 break;
166 }
167
168 return err;
169 }
170
nft_nat_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])171 static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
172 const struct nlattr * const tb[])
173 {
174 struct nft_nat *priv = nft_expr_priv(expr);
175 unsigned int alen, plen;
176 u32 family;
177 int err;
178
179 if (tb[NFTA_NAT_TYPE] == NULL ||
180 (tb[NFTA_NAT_REG_ADDR_MIN] == NULL &&
181 tb[NFTA_NAT_REG_PROTO_MIN] == NULL))
182 return -EINVAL;
183
184 switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
185 case NFT_NAT_SNAT:
186 priv->type = NF_NAT_MANIP_SRC;
187 break;
188 case NFT_NAT_DNAT:
189 priv->type = NF_NAT_MANIP_DST;
190 break;
191 default:
192 return -EOPNOTSUPP;
193 }
194
195 if (tb[NFTA_NAT_FAMILY] == NULL)
196 return -EINVAL;
197
198 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
199 if (ctx->family != NFPROTO_INET && ctx->family != family)
200 return -EOPNOTSUPP;
201
202 switch (family) {
203 case NFPROTO_IPV4:
204 alen = sizeof_field(struct nf_nat_range, min_addr.ip);
205 break;
206 case NFPROTO_IPV6:
207 alen = sizeof_field(struct nf_nat_range, min_addr.ip6);
208 break;
209 default:
210 if (tb[NFTA_NAT_REG_ADDR_MIN])
211 return -EAFNOSUPPORT;
212 break;
213 }
214 priv->family = family;
215
216 if (tb[NFTA_NAT_REG_ADDR_MIN]) {
217 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN],
218 &priv->sreg_addr_min, alen);
219 if (err < 0)
220 return err;
221
222 if (tb[NFTA_NAT_REG_ADDR_MAX]) {
223 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX],
224 &priv->sreg_addr_max,
225 alen);
226 if (err < 0)
227 return err;
228 } else {
229 priv->sreg_addr_max = priv->sreg_addr_min;
230 }
231
232 priv->flags |= NF_NAT_RANGE_MAP_IPS;
233 }
234
235 plen = sizeof_field(struct nf_nat_range, min_proto.all);
236 if (tb[NFTA_NAT_REG_PROTO_MIN]) {
237 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN],
238 &priv->sreg_proto_min, plen);
239 if (err < 0)
240 return err;
241
242 if (tb[NFTA_NAT_REG_PROTO_MAX]) {
243 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX],
244 &priv->sreg_proto_max,
245 plen);
246 if (err < 0)
247 return err;
248 } else {
249 priv->sreg_proto_max = priv->sreg_proto_min;
250 }
251
252 priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
253 }
254
255 if (tb[NFTA_NAT_FLAGS])
256 priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS]));
257
258 return nf_ct_netns_get(ctx->net, family);
259 }
260
nft_nat_dump(struct sk_buff * skb,const struct nft_expr * expr,bool reset)261 static int nft_nat_dump(struct sk_buff *skb,
262 const struct nft_expr *expr, bool reset)
263 {
264 const struct nft_nat *priv = nft_expr_priv(expr);
265
266 switch (priv->type) {
267 case NF_NAT_MANIP_SRC:
268 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
269 goto nla_put_failure;
270 break;
271 case NF_NAT_MANIP_DST:
272 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
273 goto nla_put_failure;
274 break;
275 }
276
277 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
278 goto nla_put_failure;
279
280 if (priv->sreg_addr_min) {
281 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN,
282 priv->sreg_addr_min) ||
283 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX,
284 priv->sreg_addr_max))
285 goto nla_put_failure;
286 }
287
288 if (priv->sreg_proto_min) {
289 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN,
290 priv->sreg_proto_min) ||
291 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX,
292 priv->sreg_proto_max))
293 goto nla_put_failure;
294 }
295
296 if (priv->flags != 0) {
297 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags)))
298 goto nla_put_failure;
299 }
300
301 return 0;
302
303 nla_put_failure:
304 return -1;
305 }
306
307 static void
nft_nat_destroy(const struct nft_ctx * ctx,const struct nft_expr * expr)308 nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
309 {
310 const struct nft_nat *priv = nft_expr_priv(expr);
311
312 nf_ct_netns_put(ctx->net, priv->family);
313 }
314
315 static struct nft_expr_type nft_nat_type;
316 static const struct nft_expr_ops nft_nat_ops = {
317 .type = &nft_nat_type,
318 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
319 .eval = nft_nat_eval,
320 .init = nft_nat_init,
321 .destroy = nft_nat_destroy,
322 .dump = nft_nat_dump,
323 .validate = nft_nat_validate,
324 .reduce = NFT_REDUCE_READONLY,
325 };
326
327 static struct nft_expr_type nft_nat_type __read_mostly = {
328 .name = "nat",
329 .ops = &nft_nat_ops,
330 .policy = nft_nat_policy,
331 .maxattr = NFTA_NAT_MAX,
332 .owner = THIS_MODULE,
333 };
334
335 #ifdef CONFIG_NF_TABLES_INET
nft_nat_inet_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)336 static void nft_nat_inet_eval(const struct nft_expr *expr,
337 struct nft_regs *regs,
338 const struct nft_pktinfo *pkt)
339 {
340 const struct nft_nat *priv = nft_expr_priv(expr);
341
342 if (priv->family == nft_pf(pkt) ||
343 priv->family == NFPROTO_INET)
344 nft_nat_eval(expr, regs, pkt);
345 }
346
347 static const struct nft_expr_ops nft_nat_inet_ops = {
348 .type = &nft_nat_type,
349 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
350 .eval = nft_nat_inet_eval,
351 .init = nft_nat_init,
352 .destroy = nft_nat_destroy,
353 .dump = nft_nat_dump,
354 .validate = nft_nat_validate,
355 .reduce = NFT_REDUCE_READONLY,
356 };
357
358 static struct nft_expr_type nft_inet_nat_type __read_mostly = {
359 .name = "nat",
360 .family = NFPROTO_INET,
361 .ops = &nft_nat_inet_ops,
362 .policy = nft_nat_policy,
363 .maxattr = NFTA_NAT_MAX,
364 .owner = THIS_MODULE,
365 };
366
nft_nat_inet_module_init(void)367 static int nft_nat_inet_module_init(void)
368 {
369 return nft_register_expr(&nft_inet_nat_type);
370 }
371
nft_nat_inet_module_exit(void)372 static void nft_nat_inet_module_exit(void)
373 {
374 nft_unregister_expr(&nft_inet_nat_type);
375 }
376 #else
nft_nat_inet_module_init(void)377 static int nft_nat_inet_module_init(void) { return 0; }
nft_nat_inet_module_exit(void)378 static void nft_nat_inet_module_exit(void) { }
379 #endif
380
nft_nat_module_init(void)381 static int __init nft_nat_module_init(void)
382 {
383 int ret = nft_nat_inet_module_init();
384
385 if (ret)
386 return ret;
387
388 ret = nft_register_expr(&nft_nat_type);
389 if (ret)
390 nft_nat_inet_module_exit();
391
392 return ret;
393 }
394
nft_nat_module_exit(void)395 static void __exit nft_nat_module_exit(void)
396 {
397 nft_nat_inet_module_exit();
398 nft_unregister_expr(&nft_nat_type);
399 }
400
401 module_init(nft_nat_module_init);
402 module_exit(nft_nat_module_exit);
403
404 MODULE_LICENSE("GPL");
405 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
406 MODULE_ALIAS_NFT_EXPR("nat");
407 MODULE_DESCRIPTION("Network Address Translation support");
408