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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
b4219952 HX |
2 | /* |
3 | * Stateless NAT actions | |
4 | * | |
5 | * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> | |
b4219952 HX |
6 | */ |
7 | ||
8 | #include <linux/errno.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/netfilter.h> | |
13 | #include <linux/rtnetlink.h> | |
14 | #include <linux/skbuff.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/spinlock.h> | |
17 | #include <linux/string.h> | |
18 | #include <linux/tc_act/tc_nat.h> | |
19 | #include <net/act_api.h> | |
1e45d043 | 20 | #include <net/pkt_cls.h> |
b4219952 HX |
21 | #include <net/icmp.h> |
22 | #include <net/ip.h> | |
23 | #include <net/netlink.h> | |
24 | #include <net/tc_act/tc_nat.h> | |
25 | #include <net/tcp.h> | |
26 | #include <net/udp.h> | |
871cf386 | 27 | #include <net/tc_wrapper.h> |
b4219952 | 28 | |
a85a970a | 29 | static struct tc_action_ops act_nat_ops; |
ddf97ccd | 30 | |
53b2bf3f PM |
31 | static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = { |
32 | [TCA_NAT_PARMS] = { .len = sizeof(struct tc_nat) }, | |
33 | }; | |
34 | ||
c1b52739 | 35 | static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est, |
695176bf | 36 | struct tc_action **a, struct tcf_proto *tp, |
abbb0d33 | 37 | u32 flags, struct netlink_ext_ack *extack) |
b4219952 | 38 | { |
acd0a7ab | 39 | struct tc_action_net *tn = net_generic(net, act_nat_ops.net_id); |
695176bf | 40 | bool bind = flags & TCA_ACT_FLAGS_BIND; |
7d12057b | 41 | struct tcf_nat_parms *nparm, *oparm; |
7ba699c6 | 42 | struct nlattr *tb[TCA_NAT_MAX + 1]; |
1e45d043 | 43 | struct tcf_chain *goto_ch = NULL; |
b4219952 | 44 | struct tc_nat *parm; |
cee63723 | 45 | int ret = 0, err; |
b4219952 | 46 | struct tcf_nat *p; |
7be8ef2c | 47 | u32 index; |
b4219952 | 48 | |
cee63723 | 49 | if (nla == NULL) |
b4219952 HX |
50 | return -EINVAL; |
51 | ||
8cb08174 JB |
52 | err = nla_parse_nested_deprecated(tb, TCA_NAT_MAX, nla, nat_policy, |
53 | NULL); | |
cee63723 PM |
54 | if (err < 0) |
55 | return err; | |
56 | ||
53b2bf3f | 57 | if (tb[TCA_NAT_PARMS] == NULL) |
b4219952 | 58 | return -EINVAL; |
7ba699c6 | 59 | parm = nla_data(tb[TCA_NAT_PARMS]); |
7be8ef2c DL |
60 | index = parm->index; |
61 | err = tcf_idr_check_alloc(tn, &index, a, bind); | |
0190c1d4 | 62 | if (!err) { |
7d12057b PT |
63 | ret = tcf_idr_create_from_flags(tn, index, est, a, &act_nat_ops, |
64 | bind, flags); | |
0190c1d4 | 65 | if (ret) { |
7be8ef2c | 66 | tcf_idr_cleanup(tn, index); |
86062033 | 67 | return ret; |
0190c1d4 | 68 | } |
b4219952 | 69 | ret = ACT_P_CREATED; |
0190c1d4 | 70 | } else if (err > 0) { |
1a29321e JHS |
71 | if (bind) |
72 | return 0; | |
695176bf | 73 | if (!(flags & TCA_ACT_FLAGS_REPLACE)) { |
4e8ddd7f | 74 | tcf_idr_release(*a, bind); |
b4219952 | 75 | return -EEXIST; |
4e8ddd7f | 76 | } |
0190c1d4 VB |
77 | } else { |
78 | return err; | |
b4219952 | 79 | } |
1e45d043 DC |
80 | err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); |
81 | if (err < 0) | |
82 | goto release_idr; | |
7d12057b PT |
83 | |
84 | nparm = kzalloc(sizeof(*nparm), GFP_KERNEL); | |
85 | if (!nparm) { | |
86 | err = -ENOMEM; | |
87 | goto release_idr; | |
88 | } | |
89 | ||
90 | nparm->old_addr = parm->old_addr; | |
91 | nparm->new_addr = parm->new_addr; | |
92 | nparm->mask = parm->mask; | |
93 | nparm->flags = parm->flags; | |
94 | ||
a85a970a | 95 | p = to_tcf_nat(*a); |
b4219952 HX |
96 | |
97 | spin_lock_bh(&p->tcf_lock); | |
1e45d043 | 98 | goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); |
7d12057b | 99 | oparm = rcu_replace_pointer(p->parms, nparm, lockdep_is_held(&p->tcf_lock)); |
b4219952 | 100 | spin_unlock_bh(&p->tcf_lock); |
7d12057b | 101 | |
1e45d043 DC |
102 | if (goto_ch) |
103 | tcf_chain_put_by_act(goto_ch); | |
b4219952 | 104 | |
7d12057b PT |
105 | if (oparm) |
106 | kfree_rcu(oparm, rcu); | |
107 | ||
b4219952 | 108 | return ret; |
1e45d043 DC |
109 | release_idr: |
110 | tcf_idr_release(*a, bind); | |
111 | return err; | |
b4219952 HX |
112 | } |
113 | ||
871cf386 PT |
114 | TC_INDIRECT_SCOPE int tcf_nat_act(struct sk_buff *skb, |
115 | const struct tc_action *a, | |
116 | struct tcf_result *res) | |
b4219952 | 117 | { |
a85a970a | 118 | struct tcf_nat *p = to_tcf_nat(a); |
7d12057b | 119 | struct tcf_nat_parms *parms; |
b4219952 HX |
120 | struct iphdr *iph; |
121 | __be32 old_addr; | |
122 | __be32 new_addr; | |
123 | __be32 mask; | |
124 | __be32 addr; | |
125 | int egress; | |
126 | int action; | |
127 | int ihl; | |
36d12690 | 128 | int noff; |
b4219952 | 129 | |
9c4a4e48 | 130 | tcf_lastuse_update(&p->tcf_tm); |
7d12057b | 131 | tcf_action_update_bstats(&p->common, skb); |
b4219952 | 132 | |
7d12057b | 133 | action = READ_ONCE(p->tcf_action); |
b4219952 | 134 | |
7d12057b PT |
135 | parms = rcu_dereference_bh(p->parms); |
136 | old_addr = parms->old_addr; | |
137 | new_addr = parms->new_addr; | |
138 | mask = parms->mask; | |
139 | egress = parms->flags & TCA_NAT_FLAG_EGRESS; | |
b4219952 HX |
140 | |
141 | if (unlikely(action == TC_ACT_SHOT)) | |
142 | goto drop; | |
143 | ||
36d12690 CG |
144 | noff = skb_network_offset(skb); |
145 | if (!pskb_may_pull(skb, sizeof(*iph) + noff)) | |
b4219952 HX |
146 | goto drop; |
147 | ||
148 | iph = ip_hdr(skb); | |
149 | ||
150 | if (egress) | |
151 | addr = iph->saddr; | |
152 | else | |
153 | addr = iph->daddr; | |
154 | ||
155 | if (!((old_addr ^ addr) & mask)) { | |
3697649f | 156 | if (skb_try_make_writable(skb, sizeof(*iph) + noff)) |
b4219952 HX |
157 | goto drop; |
158 | ||
159 | new_addr &= mask; | |
160 | new_addr |= addr & ~mask; | |
161 | ||
162 | /* Rewrite IP header */ | |
163 | iph = ip_hdr(skb); | |
164 | if (egress) | |
165 | iph->saddr = new_addr; | |
166 | else | |
167 | iph->daddr = new_addr; | |
168 | ||
be0ea7d5 | 169 | csum_replace4(&iph->check, addr, new_addr); |
33c29dde CG |
170 | } else if ((iph->frag_off & htons(IP_OFFSET)) || |
171 | iph->protocol != IPPROTO_ICMP) { | |
172 | goto out; | |
b4219952 HX |
173 | } |
174 | ||
175 | ihl = iph->ihl * 4; | |
176 | ||
177 | /* It would be nice to share code with stateful NAT. */ | |
178 | switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) { | |
179 | case IPPROTO_TCP: | |
180 | { | |
181 | struct tcphdr *tcph; | |
182 | ||
36d12690 | 183 | if (!pskb_may_pull(skb, ihl + sizeof(*tcph) + noff) || |
3697649f | 184 | skb_try_make_writable(skb, ihl + sizeof(*tcph) + noff)) |
b4219952 HX |
185 | goto drop; |
186 | ||
187 | tcph = (void *)(skb_network_header(skb) + ihl); | |
4b048d6d TH |
188 | inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr, |
189 | true); | |
b4219952 HX |
190 | break; |
191 | } | |
192 | case IPPROTO_UDP: | |
193 | { | |
194 | struct udphdr *udph; | |
195 | ||
36d12690 | 196 | if (!pskb_may_pull(skb, ihl + sizeof(*udph) + noff) || |
3697649f | 197 | skb_try_make_writable(skb, ihl + sizeof(*udph) + noff)) |
b4219952 HX |
198 | goto drop; |
199 | ||
200 | udph = (void *)(skb_network_header(skb) + ihl); | |
201 | if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) { | |
be0ea7d5 | 202 | inet_proto_csum_replace4(&udph->check, skb, addr, |
4b048d6d | 203 | new_addr, true); |
b4219952 HX |
204 | if (!udph->check) |
205 | udph->check = CSUM_MANGLED_0; | |
206 | } | |
207 | break; | |
208 | } | |
209 | case IPPROTO_ICMP: | |
210 | { | |
211 | struct icmphdr *icmph; | |
212 | ||
36d12690 | 213 | if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + noff)) |
b4219952 HX |
214 | goto drop; |
215 | ||
216 | icmph = (void *)(skb_network_header(skb) + ihl); | |
217 | ||
54074f1d | 218 | if (!icmp_is_err(icmph->type)) |
b4219952 HX |
219 | break; |
220 | ||
36d12690 CG |
221 | if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph) + |
222 | noff)) | |
70c2efa5 CG |
223 | goto drop; |
224 | ||
072d79a3 | 225 | icmph = (void *)(skb_network_header(skb) + ihl); |
b4219952 HX |
226 | iph = (void *)(icmph + 1); |
227 | if (egress) | |
228 | addr = iph->daddr; | |
229 | else | |
230 | addr = iph->saddr; | |
231 | ||
232 | if ((old_addr ^ addr) & mask) | |
233 | break; | |
234 | ||
3697649f DB |
235 | if (skb_try_make_writable(skb, ihl + sizeof(*icmph) + |
236 | sizeof(*iph) + noff)) | |
b4219952 HX |
237 | goto drop; |
238 | ||
239 | icmph = (void *)(skb_network_header(skb) + ihl); | |
240 | iph = (void *)(icmph + 1); | |
241 | ||
242 | new_addr &= mask; | |
243 | new_addr |= addr & ~mask; | |
244 | ||
245 | /* XXX Fix up the inner checksums. */ | |
246 | if (egress) | |
247 | iph->daddr = new_addr; | |
248 | else | |
249 | iph->saddr = new_addr; | |
250 | ||
be0ea7d5 | 251 | inet_proto_csum_replace4(&icmph->checksum, skb, addr, new_addr, |
4b048d6d | 252 | false); |
b4219952 HX |
253 | break; |
254 | } | |
255 | default: | |
256 | break; | |
257 | } | |
258 | ||
33c29dde | 259 | out: |
b4219952 HX |
260 | return action; |
261 | ||
262 | drop: | |
7d12057b | 263 | tcf_action_inc_drop_qstats(&p->common); |
b4219952 HX |
264 | return TC_ACT_SHOT; |
265 | } | |
266 | ||
267 | static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a, | |
268 | int bind, int ref) | |
269 | { | |
270 | unsigned char *b = skb_tail_pointer(skb); | |
a85a970a | 271 | struct tcf_nat *p = to_tcf_nat(a); |
1c40be12 | 272 | struct tc_nat opt = { |
1c40be12 | 273 | .index = p->tcf_index, |
036bb443 VB |
274 | .refcnt = refcount_read(&p->tcf_refcnt) - ref, |
275 | .bindcnt = atomic_read(&p->tcf_bindcnt) - bind, | |
1c40be12 | 276 | }; |
7d12057b | 277 | struct tcf_nat_parms *parms; |
b4219952 | 278 | struct tcf_t t; |
b4219952 | 279 | |
f20a4d01 | 280 | spin_lock_bh(&p->tcf_lock); |
7d12057b | 281 | |
f20a4d01 VB |
282 | opt.action = p->tcf_action; |
283 | ||
7d12057b PT |
284 | parms = rcu_dereference_protected(p->parms, lockdep_is_held(&p->tcf_lock)); |
285 | ||
286 | opt.old_addr = parms->old_addr; | |
287 | opt.new_addr = parms->new_addr; | |
288 | opt.mask = parms->mask; | |
289 | opt.flags = parms->flags; | |
290 | ||
1b34ec43 DM |
291 | if (nla_put(skb, TCA_NAT_PARMS, sizeof(opt), &opt)) |
292 | goto nla_put_failure; | |
48d8ee16 JHS |
293 | |
294 | tcf_tm_dump(&t, &p->tcf_tm); | |
9854518e | 295 | if (nla_put_64bit(skb, TCA_NAT_TM, sizeof(t), &t, TCA_NAT_PAD)) |
1b34ec43 | 296 | goto nla_put_failure; |
f20a4d01 | 297 | spin_unlock_bh(&p->tcf_lock); |
b4219952 | 298 | |
b4219952 HX |
299 | return skb->len; |
300 | ||
7ba699c6 | 301 | nla_put_failure: |
f20a4d01 | 302 | spin_unlock_bh(&p->tcf_lock); |
b4219952 | 303 | nlmsg_trim(skb, b); |
b4219952 HX |
304 | return -1; |
305 | } | |
306 | ||
7d12057b PT |
307 | static void tcf_nat_cleanup(struct tc_action *a) |
308 | { | |
309 | struct tcf_nat *p = to_tcf_nat(a); | |
310 | struct tcf_nat_parms *parms; | |
311 | ||
312 | parms = rcu_dereference_protected(p->parms, 1); | |
313 | if (parms) | |
314 | kfree_rcu(parms, rcu); | |
315 | } | |
316 | ||
b4219952 HX |
317 | static struct tc_action_ops act_nat_ops = { |
318 | .kind = "nat", | |
eddd2cf1 | 319 | .id = TCA_ID_NAT, |
b4219952 | 320 | .owner = THIS_MODULE, |
0390514f | 321 | .act = tcf_nat_act, |
b4219952 | 322 | .dump = tcf_nat_dump, |
b4219952 | 323 | .init = tcf_nat_init, |
7d12057b | 324 | .cleanup = tcf_nat_cleanup, |
a85a970a | 325 | .size = sizeof(struct tcf_nat), |
ddf97ccd WC |
326 | }; |
327 | ||
328 | static __net_init int nat_init_net(struct net *net) | |
329 | { | |
acd0a7ab | 330 | struct tc_action_net *tn = net_generic(net, act_nat_ops.net_id); |
ddf97ccd | 331 | |
981471bd | 332 | return tc_action_net_init(net, tn, &act_nat_ops); |
ddf97ccd WC |
333 | } |
334 | ||
039af9c6 | 335 | static void __net_exit nat_exit_net(struct list_head *net_list) |
ddf97ccd | 336 | { |
acd0a7ab | 337 | tc_action_net_exit(net_list, act_nat_ops.net_id); |
ddf97ccd WC |
338 | } |
339 | ||
340 | static struct pernet_operations nat_net_ops = { | |
341 | .init = nat_init_net, | |
039af9c6 | 342 | .exit_batch = nat_exit_net, |
acd0a7ab | 343 | .id = &act_nat_ops.net_id, |
ddf97ccd | 344 | .size = sizeof(struct tc_action_net), |
b4219952 HX |
345 | }; |
346 | ||
347 | MODULE_DESCRIPTION("Stateless NAT actions"); | |
348 | MODULE_LICENSE("GPL"); | |
349 | ||
350 | static int __init nat_init_module(void) | |
351 | { | |
ddf97ccd | 352 | return tcf_register_action(&act_nat_ops, &nat_net_ops); |
b4219952 HX |
353 | } |
354 | ||
355 | static void __exit nat_cleanup_module(void) | |
356 | { | |
ddf97ccd | 357 | tcf_unregister_action(&act_nat_ops, &nat_net_ops); |
b4219952 HX |
358 | } |
359 | ||
360 | module_init(nat_init_module); | |
361 | module_exit(nat_cleanup_module); |