This source file includes following definitions.
- tcf_nat_init
- tcf_nat_act
- tcf_nat_dump
- tcf_nat_walker
- tcf_nat_search
- nat_init_net
- nat_exit_net
- nat_init_module
- nat_cleanup_module
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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, int ovr, int bind,
38 bool rtnl_held, struct tcf_proto *tp,
39 struct netlink_ext_ack *extack)
40 {
41 struct tc_action_net *tn = net_generic(net, nat_net_id);
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);
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 (!ovr) {
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 if (ret == ACT_P_CREATED)
97 tcf_idr_insert(tn, *a);
98
99 return ret;
100 release_idr:
101 tcf_idr_release(*a, bind);
102 return err;
103 }
104
105 static int tcf_nat_act(struct sk_buff *skb, const struct tc_action *a,
106 struct tcf_result *res)
107 {
108 struct tcf_nat *p = to_tcf_nat(a);
109 struct iphdr *iph;
110 __be32 old_addr;
111 __be32 new_addr;
112 __be32 mask;
113 __be32 addr;
114 int egress;
115 int action;
116 int ihl;
117 int noff;
118
119 spin_lock(&p->tcf_lock);
120
121 tcf_lastuse_update(&p->tcf_tm);
122 old_addr = p->old_addr;
123 new_addr = p->new_addr;
124 mask = p->mask;
125 egress = p->flags & TCA_NAT_FLAG_EGRESS;
126 action = p->tcf_action;
127
128 bstats_update(&p->tcf_bstats, skb);
129
130 spin_unlock(&p->tcf_lock);
131
132 if (unlikely(action == TC_ACT_SHOT))
133 goto drop;
134
135 noff = skb_network_offset(skb);
136 if (!pskb_may_pull(skb, sizeof(*iph) + noff))
137 goto drop;
138
139 iph = ip_hdr(skb);
140
141 if (egress)
142 addr = iph->saddr;
143 else
144 addr = iph->daddr;
145
146 if (!((old_addr ^ addr) & mask)) {
147 if (skb_try_make_writable(skb, sizeof(*iph) + noff))
148 goto drop;
149
150 new_addr &= mask;
151 new_addr |= addr & ~mask;
152
153
154 iph = ip_hdr(skb);
155 if (egress)
156 iph->saddr = new_addr;
157 else
158 iph->daddr = new_addr;
159
160 csum_replace4(&iph->check, addr, new_addr);
161 } else if ((iph->frag_off & htons(IP_OFFSET)) ||
162 iph->protocol != IPPROTO_ICMP) {
163 goto out;
164 }
165
166 ihl = iph->ihl * 4;
167
168
169 switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
170 case IPPROTO_TCP:
171 {
172 struct tcphdr *tcph;
173
174 if (!pskb_may_pull(skb, ihl + sizeof(*tcph) + noff) ||
175 skb_try_make_writable(skb, ihl + sizeof(*tcph) + noff))
176 goto drop;
177
178 tcph = (void *)(skb_network_header(skb) + ihl);
179 inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr,
180 true);
181 break;
182 }
183 case IPPROTO_UDP:
184 {
185 struct udphdr *udph;
186
187 if (!pskb_may_pull(skb, ihl + sizeof(*udph) + noff) ||
188 skb_try_make_writable(skb, ihl + sizeof(*udph) + noff))
189 goto drop;
190
191 udph = (void *)(skb_network_header(skb) + ihl);
192 if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
193 inet_proto_csum_replace4(&udph->check, skb, addr,
194 new_addr, true);
195 if (!udph->check)
196 udph->check = CSUM_MANGLED_0;
197 }
198 break;
199 }
200 case IPPROTO_ICMP:
201 {
202 struct icmphdr *icmph;
203
204 if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + noff))
205 goto drop;
206
207 icmph = (void *)(skb_network_header(skb) + ihl);
208
209 if ((icmph->type != ICMP_DEST_UNREACH) &&
210 (icmph->type != ICMP_TIME_EXCEEDED) &&
211 (icmph->type != ICMP_PARAMETERPROB))
212 break;
213
214 if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph) +
215 noff))
216 goto drop;
217
218 icmph = (void *)(skb_network_header(skb) + ihl);
219 iph = (void *)(icmph + 1);
220 if (egress)
221 addr = iph->daddr;
222 else
223 addr = iph->saddr;
224
225 if ((old_addr ^ addr) & mask)
226 break;
227
228 if (skb_try_make_writable(skb, ihl + sizeof(*icmph) +
229 sizeof(*iph) + noff))
230 goto drop;
231
232 icmph = (void *)(skb_network_header(skb) + ihl);
233 iph = (void *)(icmph + 1);
234
235 new_addr &= mask;
236 new_addr |= addr & ~mask;
237
238
239 if (egress)
240 iph->daddr = new_addr;
241 else
242 iph->saddr = new_addr;
243
244 inet_proto_csum_replace4(&icmph->checksum, skb, addr, new_addr,
245 false);
246 break;
247 }
248 default:
249 break;
250 }
251
252 out:
253 return action;
254
255 drop:
256 spin_lock(&p->tcf_lock);
257 p->tcf_qstats.drops++;
258 spin_unlock(&p->tcf_lock);
259 return TC_ACT_SHOT;
260 }
261
262 static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a,
263 int bind, int ref)
264 {
265 unsigned char *b = skb_tail_pointer(skb);
266 struct tcf_nat *p = to_tcf_nat(a);
267 struct tc_nat opt = {
268 .index = p->tcf_index,
269 .refcnt = refcount_read(&p->tcf_refcnt) - ref,
270 .bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
271 };
272 struct tcf_t t;
273
274 spin_lock_bh(&p->tcf_lock);
275 opt.old_addr = p->old_addr;
276 opt.new_addr = p->new_addr;
277 opt.mask = p->mask;
278 opt.flags = p->flags;
279 opt.action = p->tcf_action;
280
281 if (nla_put(skb, TCA_NAT_PARMS, sizeof(opt), &opt))
282 goto nla_put_failure;
283
284 tcf_tm_dump(&t, &p->tcf_tm);
285 if (nla_put_64bit(skb, TCA_NAT_TM, sizeof(t), &t, TCA_NAT_PAD))
286 goto nla_put_failure;
287 spin_unlock_bh(&p->tcf_lock);
288
289 return skb->len;
290
291 nla_put_failure:
292 spin_unlock_bh(&p->tcf_lock);
293 nlmsg_trim(skb, b);
294 return -1;
295 }
296
297 static int tcf_nat_walker(struct net *net, struct sk_buff *skb,
298 struct netlink_callback *cb, int type,
299 const struct tc_action_ops *ops,
300 struct netlink_ext_ack *extack)
301 {
302 struct tc_action_net *tn = net_generic(net, nat_net_id);
303
304 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
305 }
306
307 static int tcf_nat_search(struct net *net, struct tc_action **a, u32 index)
308 {
309 struct tc_action_net *tn = net_generic(net, nat_net_id);
310
311 return tcf_idr_search(tn, a, index);
312 }
313
314 static struct tc_action_ops act_nat_ops = {
315 .kind = "nat",
316 .id = TCA_ID_NAT,
317 .owner = THIS_MODULE,
318 .act = tcf_nat_act,
319 .dump = tcf_nat_dump,
320 .init = tcf_nat_init,
321 .walk = tcf_nat_walker,
322 .lookup = tcf_nat_search,
323 .size = sizeof(struct tcf_nat),
324 };
325
326 static __net_init int nat_init_net(struct net *net)
327 {
328 struct tc_action_net *tn = net_generic(net, nat_net_id);
329
330 return tc_action_net_init(net, tn, &act_nat_ops);
331 }
332
333 static void __net_exit nat_exit_net(struct list_head *net_list)
334 {
335 tc_action_net_exit(net_list, nat_net_id);
336 }
337
338 static struct pernet_operations nat_net_ops = {
339 .init = nat_init_net,
340 .exit_batch = nat_exit_net,
341 .id = &nat_net_id,
342 .size = sizeof(struct tc_action_net),
343 };
344
345 MODULE_DESCRIPTION("Stateless NAT actions");
346 MODULE_LICENSE("GPL");
347
348 static int __init nat_init_module(void)
349 {
350 return tcf_register_action(&act_nat_ops, &nat_net_ops);
351 }
352
353 static void __exit nat_cleanup_module(void)
354 {
355 tcf_unregister_action(&act_nat_ops, &nat_net_ops);
356 }
357
358 module_init(nat_init_module);
359 module_exit(nat_cleanup_module);