Merge tag 'for-linus-5.15b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel...
[platform/kernel/linux-starfive.git] / net / sched / act_nat.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Stateless NAT actions
4  *
5  * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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>
20 #include <net/pkt_cls.h>
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>
27
28
29 static unsigned int nat_net_id;
30 static struct tc_action_ops act_nat_ops;
31
32 static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = {
33         [TCA_NAT_PARMS] = { .len = sizeof(struct tc_nat) },
34 };
35
36 static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
37                         struct tc_action **a, struct tcf_proto *tp,
38                         u32 flags, struct netlink_ext_ack *extack)
39 {
40         struct tc_action_net *tn = net_generic(net, nat_net_id);
41         bool bind = flags & TCA_ACT_FLAGS_BIND;
42         struct nlattr *tb[TCA_NAT_MAX + 1];
43         struct tcf_chain *goto_ch = NULL;
44         struct tc_nat *parm;
45         int ret = 0, err;
46         struct tcf_nat *p;
47         u32 index;
48
49         if (nla == NULL)
50                 return -EINVAL;
51
52         err = nla_parse_nested_deprecated(tb, TCA_NAT_MAX, nla, nat_policy,
53                                           NULL);
54         if (err < 0)
55                 return err;
56
57         if (tb[TCA_NAT_PARMS] == NULL)
58                 return -EINVAL;
59         parm = nla_data(tb[TCA_NAT_PARMS]);
60         index = parm->index;
61         err = tcf_idr_check_alloc(tn, &index, a, bind);
62         if (!err) {
63                 ret = tcf_idr_create(tn, index, est, a,
64                                      &act_nat_ops, bind, false, 0);
65                 if (ret) {
66                         tcf_idr_cleanup(tn, index);
67                         return ret;
68                 }
69                 ret = ACT_P_CREATED;
70         } else if (err > 0) {
71                 if (bind)
72                         return 0;
73                 if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
74                         tcf_idr_release(*a, bind);
75                         return -EEXIST;
76                 }
77         } else {
78                 return err;
79         }
80         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
81         if (err < 0)
82                 goto release_idr;
83         p = to_tcf_nat(*a);
84
85         spin_lock_bh(&p->tcf_lock);
86         p->old_addr = parm->old_addr;
87         p->new_addr = parm->new_addr;
88         p->mask = parm->mask;
89         p->flags = parm->flags;
90
91         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
92         spin_unlock_bh(&p->tcf_lock);
93         if (goto_ch)
94                 tcf_chain_put_by_act(goto_ch);
95
96         return ret;
97 release_idr:
98         tcf_idr_release(*a, bind);
99         return err;
100 }
101
102 static int tcf_nat_act(struct sk_buff *skb, const struct tc_action *a,
103                        struct tcf_result *res)
104 {
105         struct tcf_nat *p = to_tcf_nat(a);
106         struct iphdr *iph;
107         __be32 old_addr;
108         __be32 new_addr;
109         __be32 mask;
110         __be32 addr;
111         int egress;
112         int action;
113         int ihl;
114         int noff;
115
116         spin_lock(&p->tcf_lock);
117
118         tcf_lastuse_update(&p->tcf_tm);
119         old_addr = p->old_addr;
120         new_addr = p->new_addr;
121         mask = p->mask;
122         egress = p->flags & TCA_NAT_FLAG_EGRESS;
123         action = p->tcf_action;
124
125         bstats_update(&p->tcf_bstats, skb);
126
127         spin_unlock(&p->tcf_lock);
128
129         if (unlikely(action == TC_ACT_SHOT))
130                 goto drop;
131
132         noff = skb_network_offset(skb);
133         if (!pskb_may_pull(skb, sizeof(*iph) + noff))
134                 goto drop;
135
136         iph = ip_hdr(skb);
137
138         if (egress)
139                 addr = iph->saddr;
140         else
141                 addr = iph->daddr;
142
143         if (!((old_addr ^ addr) & mask)) {
144                 if (skb_try_make_writable(skb, sizeof(*iph) + noff))
145                         goto drop;
146
147                 new_addr &= mask;
148                 new_addr |= addr & ~mask;
149
150                 /* Rewrite IP header */
151                 iph = ip_hdr(skb);
152                 if (egress)
153                         iph->saddr = new_addr;
154                 else
155                         iph->daddr = new_addr;
156
157                 csum_replace4(&iph->check, addr, new_addr);
158         } else if ((iph->frag_off & htons(IP_OFFSET)) ||
159                    iph->protocol != IPPROTO_ICMP) {
160                 goto out;
161         }
162
163         ihl = iph->ihl * 4;
164
165         /* It would be nice to share code with stateful NAT. */
166         switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
167         case IPPROTO_TCP:
168         {
169                 struct tcphdr *tcph;
170
171                 if (!pskb_may_pull(skb, ihl + sizeof(*tcph) + noff) ||
172                     skb_try_make_writable(skb, ihl + sizeof(*tcph) + noff))
173                         goto drop;
174
175                 tcph = (void *)(skb_network_header(skb) + ihl);
176                 inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr,
177                                          true);
178                 break;
179         }
180         case IPPROTO_UDP:
181         {
182                 struct udphdr *udph;
183
184                 if (!pskb_may_pull(skb, ihl + sizeof(*udph) + noff) ||
185                     skb_try_make_writable(skb, ihl + sizeof(*udph) + noff))
186                         goto drop;
187
188                 udph = (void *)(skb_network_header(skb) + ihl);
189                 if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
190                         inet_proto_csum_replace4(&udph->check, skb, addr,
191                                                  new_addr, true);
192                         if (!udph->check)
193                                 udph->check = CSUM_MANGLED_0;
194                 }
195                 break;
196         }
197         case IPPROTO_ICMP:
198         {
199                 struct icmphdr *icmph;
200
201                 if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + noff))
202                         goto drop;
203
204                 icmph = (void *)(skb_network_header(skb) + ihl);
205
206                 if (!icmp_is_err(icmph->type))
207                         break;
208
209                 if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph) +
210                                         noff))
211                         goto drop;
212
213                 icmph = (void *)(skb_network_header(skb) + ihl);
214                 iph = (void *)(icmph + 1);
215                 if (egress)
216                         addr = iph->daddr;
217                 else
218                         addr = iph->saddr;
219
220                 if ((old_addr ^ addr) & mask)
221                         break;
222
223                 if (skb_try_make_writable(skb, ihl + sizeof(*icmph) +
224                                           sizeof(*iph) + noff))
225                         goto drop;
226
227                 icmph = (void *)(skb_network_header(skb) + ihl);
228                 iph = (void *)(icmph + 1);
229
230                 new_addr &= mask;
231                 new_addr |= addr & ~mask;
232
233                 /* XXX Fix up the inner checksums. */
234                 if (egress)
235                         iph->daddr = new_addr;
236                 else
237                         iph->saddr = new_addr;
238
239                 inet_proto_csum_replace4(&icmph->checksum, skb, addr, new_addr,
240                                          false);
241                 break;
242         }
243         default:
244                 break;
245         }
246
247 out:
248         return action;
249
250 drop:
251         spin_lock(&p->tcf_lock);
252         p->tcf_qstats.drops++;
253         spin_unlock(&p->tcf_lock);
254         return TC_ACT_SHOT;
255 }
256
257 static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a,
258                         int bind, int ref)
259 {
260         unsigned char *b = skb_tail_pointer(skb);
261         struct tcf_nat *p = to_tcf_nat(a);
262         struct tc_nat opt = {
263                 .index    = p->tcf_index,
264                 .refcnt   = refcount_read(&p->tcf_refcnt) - ref,
265                 .bindcnt  = atomic_read(&p->tcf_bindcnt) - bind,
266         };
267         struct tcf_t t;
268
269         spin_lock_bh(&p->tcf_lock);
270         opt.old_addr = p->old_addr;
271         opt.new_addr = p->new_addr;
272         opt.mask = p->mask;
273         opt.flags = p->flags;
274         opt.action = p->tcf_action;
275
276         if (nla_put(skb, TCA_NAT_PARMS, sizeof(opt), &opt))
277                 goto nla_put_failure;
278
279         tcf_tm_dump(&t, &p->tcf_tm);
280         if (nla_put_64bit(skb, TCA_NAT_TM, sizeof(t), &t, TCA_NAT_PAD))
281                 goto nla_put_failure;
282         spin_unlock_bh(&p->tcf_lock);
283
284         return skb->len;
285
286 nla_put_failure:
287         spin_unlock_bh(&p->tcf_lock);
288         nlmsg_trim(skb, b);
289         return -1;
290 }
291
292 static int tcf_nat_walker(struct net *net, struct sk_buff *skb,
293                           struct netlink_callback *cb, int type,
294                           const struct tc_action_ops *ops,
295                           struct netlink_ext_ack *extack)
296 {
297         struct tc_action_net *tn = net_generic(net, nat_net_id);
298
299         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
300 }
301
302 static int tcf_nat_search(struct net *net, struct tc_action **a, u32 index)
303 {
304         struct tc_action_net *tn = net_generic(net, nat_net_id);
305
306         return tcf_idr_search(tn, a, index);
307 }
308
309 static struct tc_action_ops act_nat_ops = {
310         .kind           =       "nat",
311         .id             =       TCA_ID_NAT,
312         .owner          =       THIS_MODULE,
313         .act            =       tcf_nat_act,
314         .dump           =       tcf_nat_dump,
315         .init           =       tcf_nat_init,
316         .walk           =       tcf_nat_walker,
317         .lookup         =       tcf_nat_search,
318         .size           =       sizeof(struct tcf_nat),
319 };
320
321 static __net_init int nat_init_net(struct net *net)
322 {
323         struct tc_action_net *tn = net_generic(net, nat_net_id);
324
325         return tc_action_net_init(net, tn, &act_nat_ops);
326 }
327
328 static void __net_exit nat_exit_net(struct list_head *net_list)
329 {
330         tc_action_net_exit(net_list, nat_net_id);
331 }
332
333 static struct pernet_operations nat_net_ops = {
334         .init = nat_init_net,
335         .exit_batch = nat_exit_net,
336         .id   = &nat_net_id,
337         .size = sizeof(struct tc_action_net),
338 };
339
340 MODULE_DESCRIPTION("Stateless NAT actions");
341 MODULE_LICENSE("GPL");
342
343 static int __init nat_init_module(void)
344 {
345         return tcf_register_action(&act_nat_ops, &nat_net_ops);
346 }
347
348 static void __exit nat_cleanup_module(void)
349 {
350         tcf_unregister_action(&act_nat_ops, &nat_net_ops);
351 }
352
353 module_init(nat_init_module);
354 module_exit(nat_cleanup_module);