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Linux kernel mirror (for testing)
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linux
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
23struct 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
33static 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
53static 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
63static 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
103static 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
128static 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
138static 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
165static 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 return -EAFNOSUPPORT;
205 }
206 priv->family = family;
207
208 if (tb[NFTA_NAT_REG_ADDR_MIN]) {
209 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN],
210 &priv->sreg_addr_min, alen);
211 if (err < 0)
212 return err;
213
214 if (tb[NFTA_NAT_REG_ADDR_MAX]) {
215 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX],
216 &priv->sreg_addr_max,
217 alen);
218 if (err < 0)
219 return err;
220 } else {
221 priv->sreg_addr_max = priv->sreg_addr_min;
222 }
223
224 priv->flags |= NF_NAT_RANGE_MAP_IPS;
225 }
226
227 plen = sizeof_field(struct nf_nat_range, min_addr.all);
228 if (tb[NFTA_NAT_REG_PROTO_MIN]) {
229 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN],
230 &priv->sreg_proto_min, plen);
231 if (err < 0)
232 return err;
233
234 if (tb[NFTA_NAT_REG_PROTO_MAX]) {
235 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX],
236 &priv->sreg_proto_max,
237 plen);
238 if (err < 0)
239 return err;
240 } else {
241 priv->sreg_proto_max = priv->sreg_proto_min;
242 }
243
244 priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
245 }
246
247 if (tb[NFTA_NAT_FLAGS]) {
248 priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS]));
249 if (priv->flags & ~NF_NAT_RANGE_MASK)
250 return -EOPNOTSUPP;
251 }
252
253 return nf_ct_netns_get(ctx->net, family);
254}
255
256static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
257{
258 const struct nft_nat *priv = nft_expr_priv(expr);
259
260 switch (priv->type) {
261 case NF_NAT_MANIP_SRC:
262 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
263 goto nla_put_failure;
264 break;
265 case NF_NAT_MANIP_DST:
266 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
267 goto nla_put_failure;
268 break;
269 }
270
271 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
272 goto nla_put_failure;
273
274 if (priv->sreg_addr_min) {
275 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN,
276 priv->sreg_addr_min) ||
277 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX,
278 priv->sreg_addr_max))
279 goto nla_put_failure;
280 }
281
282 if (priv->sreg_proto_min) {
283 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN,
284 priv->sreg_proto_min) ||
285 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX,
286 priv->sreg_proto_max))
287 goto nla_put_failure;
288 }
289
290 if (priv->flags != 0) {
291 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags)))
292 goto nla_put_failure;
293 }
294
295 return 0;
296
297nla_put_failure:
298 return -1;
299}
300
301static void
302nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
303{
304 const struct nft_nat *priv = nft_expr_priv(expr);
305
306 nf_ct_netns_put(ctx->net, priv->family);
307}
308
309static struct nft_expr_type nft_nat_type;
310static const struct nft_expr_ops nft_nat_ops = {
311 .type = &nft_nat_type,
312 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
313 .eval = nft_nat_eval,
314 .init = nft_nat_init,
315 .destroy = nft_nat_destroy,
316 .dump = nft_nat_dump,
317 .validate = nft_nat_validate,
318};
319
320static struct nft_expr_type nft_nat_type __read_mostly = {
321 .name = "nat",
322 .ops = &nft_nat_ops,
323 .policy = nft_nat_policy,
324 .maxattr = NFTA_NAT_MAX,
325 .owner = THIS_MODULE,
326};
327
328#ifdef CONFIG_NF_TABLES_INET
329static void nft_nat_inet_eval(const struct nft_expr *expr,
330 struct nft_regs *regs,
331 const struct nft_pktinfo *pkt)
332{
333 const struct nft_nat *priv = nft_expr_priv(expr);
334
335 if (priv->family == nft_pf(pkt))
336 nft_nat_eval(expr, regs, pkt);
337}
338
339static const struct nft_expr_ops nft_nat_inet_ops = {
340 .type = &nft_nat_type,
341 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
342 .eval = nft_nat_inet_eval,
343 .init = nft_nat_init,
344 .destroy = nft_nat_destroy,
345 .dump = nft_nat_dump,
346 .validate = nft_nat_validate,
347};
348
349static struct nft_expr_type nft_inet_nat_type __read_mostly = {
350 .name = "nat",
351 .family = NFPROTO_INET,
352 .ops = &nft_nat_inet_ops,
353 .policy = nft_nat_policy,
354 .maxattr = NFTA_NAT_MAX,
355 .owner = THIS_MODULE,
356};
357
358static int nft_nat_inet_module_init(void)
359{
360 return nft_register_expr(&nft_inet_nat_type);
361}
362
363static void nft_nat_inet_module_exit(void)
364{
365 nft_unregister_expr(&nft_inet_nat_type);
366}
367#else
368static int nft_nat_inet_module_init(void) { return 0; }
369static void nft_nat_inet_module_exit(void) { }
370#endif
371
372static int __init nft_nat_module_init(void)
373{
374 int ret = nft_nat_inet_module_init();
375
376 if (ret)
377 return ret;
378
379 ret = nft_register_expr(&nft_nat_type);
380 if (ret)
381 nft_nat_inet_module_exit();
382
383 return ret;
384}
385
386static void __exit nft_nat_module_exit(void)
387{
388 nft_nat_inet_module_exit();
389 nft_unregister_expr(&nft_nat_type);
390}
391
392module_init(nft_nat_module_init);
393module_exit(nft_nat_module_exit);
394
395MODULE_LICENSE("GPL");
396MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
397MODULE_ALIAS_NFT_EXPR("nat");
398MODULE_DESCRIPTION("Network Address Translation support");