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6#include <linux/kernel.h>
7#include <linux/slab.h>
8#include <linux/init.h>
9#include <linux/module.h>
10#include <linux/proc_fs.h>
11#include <linux/skbuff.h>
12#include <linux/netfilter.h>
13#include <linux/netfilter_ipv4.h>
14#include <linux/netfilter_ipv6.h>
15#include <linux/netfilter_bridge.h>
16#include <linux/seq_file.h>
17#include <linux/rcupdate.h>
18#include <net/protocol.h>
19#include <net/netfilter/nf_queue.h>
20#include <net/dst.h>
21
22#include "nf_internals.h"
23
24
25
26
27
28
29
30
31
32
33
34void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh)
35{
36
37 WARN_ON(rcu_access_pointer(net->nf.queue_handler));
38 rcu_assign_pointer(net->nf.queue_handler, qh);
39}
40EXPORT_SYMBOL(nf_register_queue_handler);
41
42
43void nf_unregister_queue_handler(struct net *net)
44{
45 RCU_INIT_POINTER(net->nf.queue_handler, NULL);
46}
47EXPORT_SYMBOL(nf_unregister_queue_handler);
48
49void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
50{
51 struct nf_hook_state *state = &entry->state;
52
53
54 if (state->in)
55 dev_put(state->in);
56 if (state->out)
57 dev_put(state->out);
58 if (state->sk)
59 sock_put(state->sk);
60#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
61 if (entry->skb->nf_bridge) {
62 struct net_device *physdev;
63
64 physdev = nf_bridge_get_physindev(entry->skb);
65 if (physdev)
66 dev_put(physdev);
67 physdev = nf_bridge_get_physoutdev(entry->skb);
68 if (physdev)
69 dev_put(physdev);
70 }
71#endif
72}
73EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs);
74
75
76void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
77{
78 struct nf_hook_state *state = &entry->state;
79
80 if (state->in)
81 dev_hold(state->in);
82 if (state->out)
83 dev_hold(state->out);
84 if (state->sk)
85 sock_hold(state->sk);
86#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
87 if (entry->skb->nf_bridge) {
88 struct net_device *physdev;
89
90 physdev = nf_bridge_get_physindev(entry->skb);
91 if (physdev)
92 dev_hold(physdev);
93 physdev = nf_bridge_get_physoutdev(entry->skb);
94 if (physdev)
95 dev_hold(physdev);
96 }
97#endif
98}
99EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
100
101void nf_queue_nf_hook_drop(struct net *net)
102{
103 const struct nf_queue_handler *qh;
104
105 rcu_read_lock();
106 qh = rcu_dereference(net->nf.queue_handler);
107 if (qh)
108 qh->nf_hook_drop(net);
109 rcu_read_unlock();
110}
111EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
112
113static void nf_ip_saveroute(const struct sk_buff *skb,
114 struct nf_queue_entry *entry)
115{
116 struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
117
118 if (entry->state.hook == NF_INET_LOCAL_OUT) {
119 const struct iphdr *iph = ip_hdr(skb);
120
121 rt_info->tos = iph->tos;
122 rt_info->daddr = iph->daddr;
123 rt_info->saddr = iph->saddr;
124 rt_info->mark = skb->mark;
125 }
126}
127
128static void nf_ip6_saveroute(const struct sk_buff *skb,
129 struct nf_queue_entry *entry)
130{
131 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
132
133 if (entry->state.hook == NF_INET_LOCAL_OUT) {
134 const struct ipv6hdr *iph = ipv6_hdr(skb);
135
136 rt_info->daddr = iph->daddr;
137 rt_info->saddr = iph->saddr;
138 rt_info->mark = skb->mark;
139 }
140}
141
142static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
143 const struct nf_hook_entries *entries,
144 unsigned int index, unsigned int queuenum)
145{
146 int status = -ENOENT;
147 struct nf_queue_entry *entry = NULL;
148 const struct nf_queue_handler *qh;
149 struct net *net = state->net;
150 unsigned int route_key_size;
151
152
153 qh = rcu_dereference(net->nf.queue_handler);
154 if (!qh) {
155 status = -ESRCH;
156 goto err;
157 }
158
159 switch (state->pf) {
160 case AF_INET:
161 route_key_size = sizeof(struct ip_rt_info);
162 break;
163 case AF_INET6:
164 route_key_size = sizeof(struct ip6_rt_info);
165 break;
166 default:
167 route_key_size = 0;
168 break;
169 }
170
171 entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
172 if (!entry) {
173 status = -ENOMEM;
174 goto err;
175 }
176
177 *entry = (struct nf_queue_entry) {
178 .skb = skb,
179 .state = *state,
180 .hook_index = index,
181 .size = sizeof(*entry) + route_key_size,
182 };
183
184 nf_queue_entry_get_refs(entry);
185 skb_dst_force(skb);
186
187 switch (entry->state.pf) {
188 case AF_INET:
189 nf_ip_saveroute(skb, entry);
190 break;
191 case AF_INET6:
192 nf_ip6_saveroute(skb, entry);
193 break;
194 }
195
196 status = qh->outfn(entry, queuenum);
197
198 if (status < 0) {
199 nf_queue_entry_release_refs(entry);
200 goto err;
201 }
202
203 return 0;
204
205err:
206 kfree(entry);
207 return status;
208}
209
210
211int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
212 const struct nf_hook_entries *entries, unsigned int index,
213 unsigned int verdict)
214{
215 int ret;
216
217 ret = __nf_queue(skb, state, entries, index, verdict >> NF_VERDICT_QBITS);
218 if (ret < 0) {
219 if (ret == -ESRCH &&
220 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
221 return 1;
222 kfree_skb(skb);
223 }
224
225 return 0;
226}
227
228static unsigned int nf_iterate(struct sk_buff *skb,
229 struct nf_hook_state *state,
230 const struct nf_hook_entries *hooks,
231 unsigned int *index)
232{
233 const struct nf_hook_entry *hook;
234 unsigned int verdict, i = *index;
235
236 while (i < hooks->num_hook_entries) {
237 hook = &hooks->hooks[i];
238repeat:
239 verdict = nf_hook_entry_hookfn(hook, skb, state);
240 if (verdict != NF_ACCEPT) {
241 if (verdict != NF_REPEAT)
242 return verdict;
243 goto repeat;
244 }
245 i++;
246 }
247
248 *index = i;
249 return NF_ACCEPT;
250}
251
252static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
253{
254 switch (pf) {
255#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
256 case NFPROTO_BRIDGE:
257 return rcu_dereference(net->nf.hooks_bridge[hooknum]);
258#endif
259 case NFPROTO_IPV4:
260 return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
261 case NFPROTO_IPV6:
262 return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
263 default:
264 WARN_ON_ONCE(1);
265 return NULL;
266 }
267
268 return NULL;
269}
270
271
272void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
273{
274 const struct nf_hook_entry *hook_entry;
275 const struct nf_hook_entries *hooks;
276 struct sk_buff *skb = entry->skb;
277 const struct net *net;
278 unsigned int i;
279 int err;
280 u8 pf;
281
282 net = entry->state.net;
283 pf = entry->state.pf;
284
285 hooks = nf_hook_entries_head(net, pf, entry->state.hook);
286
287 nf_queue_entry_release_refs(entry);
288
289 i = entry->hook_index;
290 if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
291 kfree_skb(skb);
292 kfree(entry);
293 return;
294 }
295
296 hook_entry = &hooks->hooks[i];
297
298
299 if (verdict == NF_REPEAT)
300 verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
301
302 if (verdict == NF_ACCEPT) {
303 if (nf_reroute(skb, entry) < 0)
304 verdict = NF_DROP;
305 }
306
307 if (verdict == NF_ACCEPT) {
308next_hook:
309 ++i;
310 verdict = nf_iterate(skb, &entry->state, hooks, &i);
311 }
312
313 switch (verdict & NF_VERDICT_MASK) {
314 case NF_ACCEPT:
315 case NF_STOP:
316 local_bh_disable();
317 entry->state.okfn(entry->state.net, entry->state.sk, skb);
318 local_bh_enable();
319 break;
320 case NF_QUEUE:
321 err = nf_queue(skb, &entry->state, hooks, i, verdict);
322 if (err == 1)
323 goto next_hook;
324 break;
325 case NF_STOLEN:
326 break;
327 default:
328 kfree_skb(skb);
329 }
330
331 kfree(entry);
332}
333EXPORT_SYMBOL(nf_reinject);
334