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 | |
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 | |
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(sreg: ®s->data[priv->sreg_proto_min]); |
59 | range->max_proto.all = (__force __be16) |
60 | nft_reg_load16(sreg: ®s->data[priv->sreg_proto_max]); |
61 | } |
62 | |
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 | |
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(skb: pkt->skb, ctinfo: &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: &range, regs, priv); |
116 | if (priv->flags & NF_NAT_RANGE_NETMAP) |
117 | nft_nat_setup_netmap(range: &range, pkt, priv); |
118 | } |
119 | |
120 | if (priv->sreg_proto_min) |
121 | nft_nat_setup_proto(range: &range, regs, priv); |
122 | |
123 | range.flags = priv->flags; |
124 | |
125 | regs->verdict.code = nf_nat_setup_info(ct, range: &range, maniptype: 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 | |
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(chain: ctx->chain, type: 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(chain: ctx->chain, |
153 | hook_flags: (1 << NF_INET_POST_ROUTING) | |
154 | (1 << NF_INET_LOCAL_IN)); |
155 | break; |
156 | case NFT_NAT_DNAT: |
157 | err = nft_chain_validate_hooks(chain: ctx->chain, |
158 | hook_flags: (1 << NF_INET_PRE_ROUTING) | |
159 | (1 << NF_INET_LOCAL_OUT)); |
160 | break; |
161 | } |
162 | |
163 | return err; |
164 | } |
165 | |
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(attr: tb[NFTA_NAT_REG_ADDR_MIN], |
213 | sreg: &priv->sreg_addr_min, len: alen); |
214 | if (err < 0) |
215 | return err; |
216 | |
217 | if (tb[NFTA_NAT_REG_ADDR_MAX]) { |
218 | err = nft_parse_register_load(attr: tb[NFTA_NAT_REG_ADDR_MAX], |
219 | sreg: &priv->sreg_addr_max, |
220 | len: 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(attr: tb[NFTA_NAT_REG_PROTO_MIN], |
233 | sreg: &priv->sreg_proto_min, len: plen); |
234 | if (err < 0) |
235 | return err; |
236 | |
237 | if (tb[NFTA_NAT_REG_PROTO_MAX]) { |
238 | err = nft_parse_register_load(attr: tb[NFTA_NAT_REG_PROTO_MAX], |
239 | sreg: &priv->sreg_proto_max, |
240 | len: 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(net: ctx->net, nfproto: family); |
254 | } |
255 | |
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, attrtype: 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, attrtype: NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT))) |
268 | goto nla_put_failure; |
269 | break; |
270 | } |
271 | |
272 | if (nla_put_be32(skb, attrtype: NFTA_NAT_FAMILY, htonl(priv->family))) |
273 | goto nla_put_failure; |
274 | |
275 | if (priv->sreg_addr_min) { |
276 | if (nft_dump_register(skb, attr: NFTA_NAT_REG_ADDR_MIN, |
277 | reg: priv->sreg_addr_min) || |
278 | nft_dump_register(skb, attr: NFTA_NAT_REG_ADDR_MAX, |
279 | reg: priv->sreg_addr_max)) |
280 | goto nla_put_failure; |
281 | } |
282 | |
283 | if (priv->sreg_proto_min) { |
284 | if (nft_dump_register(skb, attr: NFTA_NAT_REG_PROTO_MIN, |
285 | reg: priv->sreg_proto_min) || |
286 | nft_dump_register(skb, attr: NFTA_NAT_REG_PROTO_MAX, |
287 | reg: priv->sreg_proto_max)) |
288 | goto nla_put_failure; |
289 | } |
290 | |
291 | if (priv->flags != 0) { |
292 | if (nla_put_be32(skb, attrtype: 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 |
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(net: ctx->net, nfproto: 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 |
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 | |
362 | static int nft_nat_inet_module_init(void) |
363 | { |
364 | return nft_register_expr(&nft_inet_nat_type); |
365 | } |
366 | |
367 | static void nft_nat_inet_module_exit(void) |
368 | { |
369 | nft_unregister_expr(&nft_inet_nat_type); |
370 | } |
371 | #else |
372 | static int nft_nat_inet_module_init(void) { return 0; } |
373 | static void nft_nat_inet_module_exit(void) { } |
374 | #endif |
375 | |
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 | |
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 | |