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12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/skbuff.h>
15#include <linux/ip.h>
16#include <linux/string.h>
17#include <linux/netlink.h>
18#include <linux/netfilter.h>
19#include <linux/netfilter_ipv4.h>
20#include <linux/netfilter/nfnetlink.h>
21#include <linux/netfilter/nf_tables.h>
22#include <net/netfilter/nf_conntrack.h>
23#include <net/netfilter/nf_nat.h>
24#include <net/netfilter/nf_nat_core.h>
25#include <net/netfilter/nf_tables.h>
26#include <net/netfilter/nf_nat_l3proto.h>
27#include <net/ip.h>
28
29struct nft_nat {
30 enum nft_registers sreg_addr_min:8;
31 enum nft_registers sreg_addr_max:8;
32 enum nft_registers sreg_proto_min:8;
33 enum nft_registers sreg_proto_max:8;
34 enum nf_nat_manip_type type:8;
35 u8 family;
36 u16 flags;
37};
38
39static void nft_nat_eval(const struct nft_expr *expr,
40 struct nft_regs *regs,
41 const struct nft_pktinfo *pkt)
42{
43 const struct nft_nat *priv = nft_expr_priv(expr);
44 enum ip_conntrack_info ctinfo;
45 struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo);
46 struct nf_nat_range range;
47
48 memset(&range, 0, sizeof(range));
49 if (priv->sreg_addr_min) {
50 if (priv->family == AF_INET) {
51 range.min_addr.ip = (__force __be32)
52 regs->data[priv->sreg_addr_min];
53 range.max_addr.ip = (__force __be32)
54 regs->data[priv->sreg_addr_max];
55
56 } else {
57 memcpy(range.min_addr.ip6,
58 ®s->data[priv->sreg_addr_min],
59 sizeof(range.min_addr.ip6));
60 memcpy(range.max_addr.ip6,
61 ®s->data[priv->sreg_addr_max],
62 sizeof(range.max_addr.ip6));
63 }
64 range.flags |= NF_NAT_RANGE_MAP_IPS;
65 }
66
67 if (priv->sreg_proto_min) {
68 range.min_proto.all =
69 *(__be16 *)®s->data[priv->sreg_proto_min];
70 range.max_proto.all =
71 *(__be16 *)®s->data[priv->sreg_proto_max];
72 range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
73 }
74
75 range.flags |= priv->flags;
76
77 regs->verdict.code = nf_nat_setup_info(ct, &range, priv->type);
78}
79
80static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = {
81 [NFTA_NAT_TYPE] = { .type = NLA_U32 },
82 [NFTA_NAT_FAMILY] = { .type = NLA_U32 },
83 [NFTA_NAT_REG_ADDR_MIN] = { .type = NLA_U32 },
84 [NFTA_NAT_REG_ADDR_MAX] = { .type = NLA_U32 },
85 [NFTA_NAT_REG_PROTO_MIN] = { .type = NLA_U32 },
86 [NFTA_NAT_REG_PROTO_MAX] = { .type = NLA_U32 },
87 [NFTA_NAT_FLAGS] = { .type = NLA_U32 },
88};
89
90static int nft_nat_validate(const struct nft_ctx *ctx,
91 const struct nft_expr *expr,
92 const struct nft_data **data)
93{
94 struct nft_nat *priv = nft_expr_priv(expr);
95 int err;
96
97 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
98 if (err < 0)
99 return err;
100
101 switch (priv->type) {
102 case NFT_NAT_SNAT:
103 err = nft_chain_validate_hooks(ctx->chain,
104 (1 << NF_INET_POST_ROUTING) |
105 (1 << NF_INET_LOCAL_IN));
106 break;
107 case NFT_NAT_DNAT:
108 err = nft_chain_validate_hooks(ctx->chain,
109 (1 << NF_INET_PRE_ROUTING) |
110 (1 << NF_INET_LOCAL_OUT));
111 break;
112 }
113
114 return err;
115}
116
117static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
118 const struct nlattr * const tb[])
119{
120 struct nft_nat *priv = nft_expr_priv(expr);
121 unsigned int alen, plen;
122 u32 family;
123 int err;
124
125 if (tb[NFTA_NAT_TYPE] == NULL ||
126 (tb[NFTA_NAT_REG_ADDR_MIN] == NULL &&
127 tb[NFTA_NAT_REG_PROTO_MIN] == NULL))
128 return -EINVAL;
129
130 switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
131 case NFT_NAT_SNAT:
132 priv->type = NF_NAT_MANIP_SRC;
133 break;
134 case NFT_NAT_DNAT:
135 priv->type = NF_NAT_MANIP_DST;
136 break;
137 default:
138 return -EINVAL;
139 }
140
141 err = nft_nat_validate(ctx, expr, NULL);
142 if (err < 0)
143 return err;
144
145 if (tb[NFTA_NAT_FAMILY] == NULL)
146 return -EINVAL;
147
148 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
149 if (family != ctx->afi->family)
150 return -EOPNOTSUPP;
151
152 switch (family) {
153 case NFPROTO_IPV4:
154 alen = FIELD_SIZEOF(struct nf_nat_range, min_addr.ip);
155 break;
156 case NFPROTO_IPV6:
157 alen = FIELD_SIZEOF(struct nf_nat_range, min_addr.ip6);
158 break;
159 default:
160 return -EAFNOSUPPORT;
161 }
162 priv->family = family;
163
164 if (tb[NFTA_NAT_REG_ADDR_MIN]) {
165 priv->sreg_addr_min =
166 nft_parse_register(tb[NFTA_NAT_REG_ADDR_MIN]);
167 err = nft_validate_register_load(priv->sreg_addr_min, alen);
168 if (err < 0)
169 return err;
170
171 if (tb[NFTA_NAT_REG_ADDR_MAX]) {
172 priv->sreg_addr_max =
173 nft_parse_register(tb[NFTA_NAT_REG_ADDR_MAX]);
174
175 err = nft_validate_register_load(priv->sreg_addr_max,
176 alen);
177 if (err < 0)
178 return err;
179 } else {
180 priv->sreg_addr_max = priv->sreg_addr_min;
181 }
182 }
183
184 plen = FIELD_SIZEOF(struct nf_nat_range, min_addr.all);
185 if (tb[NFTA_NAT_REG_PROTO_MIN]) {
186 priv->sreg_proto_min =
187 nft_parse_register(tb[NFTA_NAT_REG_PROTO_MIN]);
188
189 err = nft_validate_register_load(priv->sreg_proto_min, plen);
190 if (err < 0)
191 return err;
192
193 if (tb[NFTA_NAT_REG_PROTO_MAX]) {
194 priv->sreg_proto_max =
195 nft_parse_register(tb[NFTA_NAT_REG_PROTO_MAX]);
196
197 err = nft_validate_register_load(priv->sreg_proto_max,
198 plen);
199 if (err < 0)
200 return err;
201 } else {
202 priv->sreg_proto_max = priv->sreg_proto_min;
203 }
204 }
205
206 if (tb[NFTA_NAT_FLAGS]) {
207 priv->flags = ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS]));
208 if (priv->flags & ~NF_NAT_RANGE_MASK)
209 return -EINVAL;
210 }
211
212 return 0;
213}
214
215static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
216{
217 const struct nft_nat *priv = nft_expr_priv(expr);
218
219 switch (priv->type) {
220 case NF_NAT_MANIP_SRC:
221 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
222 goto nla_put_failure;
223 break;
224 case NF_NAT_MANIP_DST:
225 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
226 goto nla_put_failure;
227 break;
228 }
229
230 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
231 goto nla_put_failure;
232
233 if (priv->sreg_addr_min) {
234 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN,
235 priv->sreg_addr_min) ||
236 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX,
237 priv->sreg_addr_max))
238 goto nla_put_failure;
239 }
240
241 if (priv->sreg_proto_min) {
242 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN,
243 priv->sreg_proto_min) ||
244 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX,
245 priv->sreg_proto_max))
246 goto nla_put_failure;
247 }
248
249 if (priv->flags != 0) {
250 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags)))
251 goto nla_put_failure;
252 }
253
254 return 0;
255
256nla_put_failure:
257 return -1;
258}
259
260static struct nft_expr_type nft_nat_type;
261static const struct nft_expr_ops nft_nat_ops = {
262 .type = &nft_nat_type,
263 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
264 .eval = nft_nat_eval,
265 .init = nft_nat_init,
266 .dump = nft_nat_dump,
267 .validate = nft_nat_validate,
268};
269
270static struct nft_expr_type nft_nat_type __read_mostly = {
271 .name = "nat",
272 .ops = &nft_nat_ops,
273 .policy = nft_nat_policy,
274 .maxattr = NFTA_NAT_MAX,
275 .owner = THIS_MODULE,
276};
277
278static int __init nft_nat_module_init(void)
279{
280 return nft_register_expr(&nft_nat_type);
281}
282
283static void __exit nft_nat_module_exit(void)
284{
285 nft_unregister_expr(&nft_nat_type);
286}
287
288module_init(nft_nat_module_init);
289module_exit(nft_nat_module_exit);
290
291MODULE_LICENSE("GPL");
292MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
293MODULE_ALIAS_NFT_EXPR("nat");
294
