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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2014 Arturo Borrero Gonzalez <arturo@debian.org>
4 */
5
6#include <linux/kernel.h>
7#include <linux/init.h>
8#include <linux/module.h>
9#include <linux/netlink.h>
10#include <linux/netfilter.h>
11#include <linux/netfilter/nf_tables.h>
12#include <net/netfilter/nf_tables.h>
13#include <net/netfilter/nf_nat.h>
14#include <net/netfilter/nf_nat_masquerade.h>
15
16struct nft_masq {
17 u32 flags;
18 u8 sreg_proto_min;
19 u8 sreg_proto_max;
20};
21
22static const struct nla_policy nft_masq_policy[NFTA_MASQ_MAX + 1] = {
23 [NFTA_MASQ_FLAGS] = { .type = NLA_U32 },
24 [NFTA_MASQ_REG_PROTO_MIN] = { .type = NLA_U32 },
25 [NFTA_MASQ_REG_PROTO_MAX] = { .type = NLA_U32 },
26};
27
28static int nft_masq_validate(const struct nft_ctx *ctx,
29 const struct nft_expr *expr,
30 const struct nft_data **data)
31{
32 int err;
33
34 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
35 if (err < 0)
36 return err;
37
38 return nft_chain_validate_hooks(ctx->chain,
39 (1 << NF_INET_POST_ROUTING));
40}
41
42static int nft_masq_init(const struct nft_ctx *ctx,
43 const struct nft_expr *expr,
44 const struct nlattr * const tb[])
45{
46 u32 plen = sizeof_field(struct nf_nat_range, min_addr.all);
47 struct nft_masq *priv = nft_expr_priv(expr);
48 int err;
49
50 if (tb[NFTA_MASQ_FLAGS]) {
51 priv->flags = ntohl(nla_get_be32(tb[NFTA_MASQ_FLAGS]));
52 if (priv->flags & ~NF_NAT_RANGE_MASK)
53 return -EINVAL;
54 }
55
56 if (tb[NFTA_MASQ_REG_PROTO_MIN]) {
57 err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MIN],
58 &priv->sreg_proto_min, plen);
59 if (err < 0)
60 return err;
61
62 if (tb[NFTA_MASQ_REG_PROTO_MAX]) {
63 err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MAX],
64 &priv->sreg_proto_max,
65 plen);
66 if (err < 0)
67 return err;
68 } else {
69 priv->sreg_proto_max = priv->sreg_proto_min;
70 }
71 }
72
73 return nf_ct_netns_get(ctx->net, ctx->family);
74}
75
76static int nft_masq_dump(struct sk_buff *skb,
77 const struct nft_expr *expr, bool reset)
78{
79 const struct nft_masq *priv = nft_expr_priv(expr);
80
81 if (priv->flags != 0 &&
82 nla_put_be32(skb, NFTA_MASQ_FLAGS, htonl(priv->flags)))
83 goto nla_put_failure;
84
85 if (priv->sreg_proto_min) {
86 if (nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MIN,
87 priv->sreg_proto_min) ||
88 nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MAX,
89 priv->sreg_proto_max))
90 goto nla_put_failure;
91 }
92
93 return 0;
94
95nla_put_failure:
96 return -1;
97}
98
99static void nft_masq_ipv4_eval(const struct nft_expr *expr,
100 struct nft_regs *regs,
101 const struct nft_pktinfo *pkt)
102{
103 struct nft_masq *priv = nft_expr_priv(expr);
104 struct nf_nat_range2 range;
105
106 memset(&range, 0, sizeof(range));
107 range.flags = priv->flags;
108 if (priv->sreg_proto_min) {
109 range.min_proto.all = (__force __be16)nft_reg_load16(
110 ®s->data[priv->sreg_proto_min]);
111 range.max_proto.all = (__force __be16)nft_reg_load16(
112 ®s->data[priv->sreg_proto_max]);
113 }
114 regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, nft_hook(pkt),
115 &range, nft_out(pkt));
116}
117
118static void
119nft_masq_ipv4_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
120{
121 nf_ct_netns_put(ctx->net, NFPROTO_IPV4);
122}
123
124static struct nft_expr_type nft_masq_ipv4_type;
125static const struct nft_expr_ops nft_masq_ipv4_ops = {
126 .type = &nft_masq_ipv4_type,
127 .size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
128 .eval = nft_masq_ipv4_eval,
129 .init = nft_masq_init,
130 .destroy = nft_masq_ipv4_destroy,
131 .dump = nft_masq_dump,
132 .validate = nft_masq_validate,
133 .reduce = NFT_REDUCE_READONLY,
134};
135
136static struct nft_expr_type nft_masq_ipv4_type __read_mostly = {
137 .family = NFPROTO_IPV4,
138 .name = "masq",
139 .ops = &nft_masq_ipv4_ops,
140 .policy = nft_masq_policy,
141 .maxattr = NFTA_MASQ_MAX,
142 .owner = THIS_MODULE,
143};
144
145#ifdef CONFIG_NF_TABLES_IPV6
146static void nft_masq_ipv6_eval(const struct nft_expr *expr,
147 struct nft_regs *regs,
148 const struct nft_pktinfo *pkt)
149{
150 struct nft_masq *priv = nft_expr_priv(expr);
151 struct nf_nat_range2 range;
152
153 memset(&range, 0, sizeof(range));
154 range.flags = priv->flags;
155 if (priv->sreg_proto_min) {
156 range.min_proto.all = (__force __be16)nft_reg_load16(
157 ®s->data[priv->sreg_proto_min]);
158 range.max_proto.all = (__force __be16)nft_reg_load16(
159 ®s->data[priv->sreg_proto_max]);
160 }
161 regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range,
162 nft_out(pkt));
163}
164
165static void
166nft_masq_ipv6_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
167{
168 nf_ct_netns_put(ctx->net, NFPROTO_IPV6);
169}
170
171static struct nft_expr_type nft_masq_ipv6_type;
172static const struct nft_expr_ops nft_masq_ipv6_ops = {
173 .type = &nft_masq_ipv6_type,
174 .size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
175 .eval = nft_masq_ipv6_eval,
176 .init = nft_masq_init,
177 .destroy = nft_masq_ipv6_destroy,
178 .dump = nft_masq_dump,
179 .validate = nft_masq_validate,
180 .reduce = NFT_REDUCE_READONLY,
181};
182
183static struct nft_expr_type nft_masq_ipv6_type __read_mostly = {
184 .family = NFPROTO_IPV6,
185 .name = "masq",
186 .ops = &nft_masq_ipv6_ops,
187 .policy = nft_masq_policy,
188 .maxattr = NFTA_MASQ_MAX,
189 .owner = THIS_MODULE,
190};
191
192static int __init nft_masq_module_init_ipv6(void)
193{
194 return nft_register_expr(&nft_masq_ipv6_type);
195}
196
197static void nft_masq_module_exit_ipv6(void)
198{
199 nft_unregister_expr(&nft_masq_ipv6_type);
200}
201#else
202static inline int nft_masq_module_init_ipv6(void) { return 0; }
203static inline void nft_masq_module_exit_ipv6(void) {}
204#endif
205
206#ifdef CONFIG_NF_TABLES_INET
207static void nft_masq_inet_eval(const struct nft_expr *expr,
208 struct nft_regs *regs,
209 const struct nft_pktinfo *pkt)
210{
211 switch (nft_pf(pkt)) {
212 case NFPROTO_IPV4:
213 return nft_masq_ipv4_eval(expr, regs, pkt);
214 case NFPROTO_IPV6:
215 return nft_masq_ipv6_eval(expr, regs, pkt);
216 }
217
218 WARN_ON_ONCE(1);
219}
220
221static void
222nft_masq_inet_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
223{
224 nf_ct_netns_put(ctx->net, NFPROTO_INET);
225}
226
227static struct nft_expr_type nft_masq_inet_type;
228static const struct nft_expr_ops nft_masq_inet_ops = {
229 .type = &nft_masq_inet_type,
230 .size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
231 .eval = nft_masq_inet_eval,
232 .init = nft_masq_init,
233 .destroy = nft_masq_inet_destroy,
234 .dump = nft_masq_dump,
235 .validate = nft_masq_validate,
236 .reduce = NFT_REDUCE_READONLY,
237};
238
239static struct nft_expr_type nft_masq_inet_type __read_mostly = {
240 .family = NFPROTO_INET,
241 .name = "masq",
242 .ops = &nft_masq_inet_ops,
243 .policy = nft_masq_policy,
244 .maxattr = NFTA_MASQ_MAX,
245 .owner = THIS_MODULE,
246};
247
248static int __init nft_masq_module_init_inet(void)
249{
250 return nft_register_expr(&nft_masq_inet_type);
251}
252
253static void nft_masq_module_exit_inet(void)
254{
255 nft_unregister_expr(&nft_masq_inet_type);
256}
257#else
258static inline int nft_masq_module_init_inet(void) { return 0; }
259static inline void nft_masq_module_exit_inet(void) {}
260#endif
261
262static int __init nft_masq_module_init(void)
263{
264 int ret;
265
266 ret = nft_masq_module_init_ipv6();
267 if (ret < 0)
268 return ret;
269
270 ret = nft_masq_module_init_inet();
271 if (ret < 0) {
272 nft_masq_module_exit_ipv6();
273 return ret;
274 }
275
276 ret = nft_register_expr(&nft_masq_ipv4_type);
277 if (ret < 0) {
278 nft_masq_module_exit_inet();
279 nft_masq_module_exit_ipv6();
280 return ret;
281 }
282
283 ret = nf_nat_masquerade_inet_register_notifiers();
284 if (ret < 0) {
285 nft_masq_module_exit_ipv6();
286 nft_masq_module_exit_inet();
287 nft_unregister_expr(&nft_masq_ipv4_type);
288 return ret;
289 }
290
291 return ret;
292}
293
294static void __exit nft_masq_module_exit(void)
295{
296 nft_masq_module_exit_ipv6();
297 nft_masq_module_exit_inet();
298 nft_unregister_expr(&nft_masq_ipv4_type);
299 nf_nat_masquerade_inet_unregister_notifiers();
300}
301
302module_init(nft_masq_module_init);
303module_exit(nft_masq_module_exit);
304
305MODULE_LICENSE("GPL");
306MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org>");
307MODULE_ALIAS_NFT_EXPR("masq");
308MODULE_DESCRIPTION("Netfilter nftables masquerade expression support");