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1/*
2 * Rusty Russell (C)2000 -- This code is GPL.
3 * Patrick McHardy (c) 2006-2012
4 */
5
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_bridge.h>
14#include <linux/seq_file.h>
15#include <linux/rcupdate.h>
16#include <net/protocol.h>
17#include <net/netfilter/nf_queue.h>
18#include <net/dst.h>
19
20#include "nf_internals.h"
21
22/*
23 * Hook for nfnetlink_queue to register its queue handler.
24 * We do this so that most of the NFQUEUE code can be modular.
25 *
26 * Once the queue is registered it must reinject all packets it
27 * receives, no matter what.
28 */
29
30/* return EBUSY when somebody else is registered, return EEXIST if the
31 * same handler is registered, return 0 in case of success. */
32void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh)
33{
34 /* should never happen, we only have one queueing backend in kernel */
35 WARN_ON(rcu_access_pointer(net->nf.queue_handler));
36 rcu_assign_pointer(net->nf.queue_handler, qh);
37}
38EXPORT_SYMBOL(nf_register_queue_handler);
39
40/* The caller must flush their queue before this */
41void nf_unregister_queue_handler(struct net *net)
42{
43 RCU_INIT_POINTER(net->nf.queue_handler, NULL);
44}
45EXPORT_SYMBOL(nf_unregister_queue_handler);
46
47void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
48{
49 struct nf_hook_state *state = &entry->state;
50
51 /* Release those devices we held, or Alexey will kill me. */
52 if (state->in)
53 dev_put(state->in);
54 if (state->out)
55 dev_put(state->out);
56 if (state->sk)
57 sock_put(state->sk);
58#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
59 if (entry->skb->nf_bridge) {
60 struct net_device *physdev;
61
62 physdev = nf_bridge_get_physindev(entry->skb);
63 if (physdev)
64 dev_put(physdev);
65 physdev = nf_bridge_get_physoutdev(entry->skb);
66 if (physdev)
67 dev_put(physdev);
68 }
69#endif
70}
71EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs);
72
73/* Bump dev refs so they don't vanish while packet is out */
74void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
75{
76 struct nf_hook_state *state = &entry->state;
77
78 if (state->in)
79 dev_hold(state->in);
80 if (state->out)
81 dev_hold(state->out);
82 if (state->sk)
83 sock_hold(state->sk);
84#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
85 if (entry->skb->nf_bridge) {
86 struct net_device *physdev;
87
88 physdev = nf_bridge_get_physindev(entry->skb);
89 if (physdev)
90 dev_hold(physdev);
91 physdev = nf_bridge_get_physoutdev(entry->skb);
92 if (physdev)
93 dev_hold(physdev);
94 }
95#endif
96}
97EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
98
99void nf_queue_nf_hook_drop(struct net *net, const struct nf_hook_entry *entry)
100{
101 const struct nf_queue_handler *qh;
102
103 rcu_read_lock();
104 qh = rcu_dereference(net->nf.queue_handler);
105 if (qh)
106 qh->nf_hook_drop(net, entry);
107 rcu_read_unlock();
108}
109
110static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
111 struct nf_hook_entry *hook_entry, unsigned int queuenum)
112{
113 int status = -ENOENT;
114 struct nf_queue_entry *entry = NULL;
115 const struct nf_afinfo *afinfo;
116 const struct nf_queue_handler *qh;
117 struct net *net = state->net;
118
119 /* QUEUE == DROP if no one is waiting, to be safe. */
120 qh = rcu_dereference(net->nf.queue_handler);
121 if (!qh) {
122 status = -ESRCH;
123 goto err;
124 }
125
126 afinfo = nf_get_afinfo(state->pf);
127 if (!afinfo)
128 goto err;
129
130 entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);
131 if (!entry) {
132 status = -ENOMEM;
133 goto err;
134 }
135
136 *entry = (struct nf_queue_entry) {
137 .skb = skb,
138 .state = *state,
139 .hook = hook_entry,
140 .size = sizeof(*entry) + afinfo->route_key_size,
141 };
142
143 nf_queue_entry_get_refs(entry);
144 skb_dst_force(skb);
145 afinfo->saveroute(skb, entry);
146 status = qh->outfn(entry, queuenum);
147
148 if (status < 0) {
149 nf_queue_entry_release_refs(entry);
150 goto err;
151 }
152
153 return 0;
154
155err:
156 kfree(entry);
157 return status;
158}
159
160/* Packets leaving via this function must come back through nf_reinject(). */
161int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
162 struct nf_hook_entry **entryp, unsigned int verdict)
163{
164 struct nf_hook_entry *entry = *entryp;
165 int ret;
166
167 ret = __nf_queue(skb, state, entry, verdict >> NF_VERDICT_QBITS);
168 if (ret < 0) {
169 if (ret == -ESRCH &&
170 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS)) {
171 *entryp = rcu_dereference(entry->next);
172 return 1;
173 }
174 kfree_skb(skb);
175 }
176
177 return 0;
178}
179
180static unsigned int nf_iterate(struct sk_buff *skb,
181 struct nf_hook_state *state,
182 struct nf_hook_entry **entryp)
183{
184 unsigned int verdict;
185
186 do {
187repeat:
188 verdict = nf_hook_entry_hookfn((*entryp), skb, state);
189 if (verdict != NF_ACCEPT) {
190 if (verdict != NF_REPEAT)
191 return verdict;
192 goto repeat;
193 }
194 *entryp = rcu_dereference((*entryp)->next);
195 } while (*entryp);
196
197 return NF_ACCEPT;
198}
199
200void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
201{
202 struct nf_hook_entry *hook_entry = entry->hook;
203 struct sk_buff *skb = entry->skb;
204 const struct nf_afinfo *afinfo;
205 int err;
206
207 nf_queue_entry_release_refs(entry);
208
209 /* Continue traversal iff userspace said ok... */
210 if (verdict == NF_REPEAT)
211 verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
212
213 if (verdict == NF_ACCEPT) {
214 afinfo = nf_get_afinfo(entry->state.pf);
215 if (!afinfo || afinfo->reroute(entry->state.net, skb, entry) < 0)
216 verdict = NF_DROP;
217 }
218
219 if (verdict == NF_ACCEPT) {
220 hook_entry = rcu_dereference(hook_entry->next);
221 if (hook_entry)
222next_hook:
223 verdict = nf_iterate(skb, &entry->state, &hook_entry);
224 }
225
226 switch (verdict & NF_VERDICT_MASK) {
227 case NF_ACCEPT:
228 case NF_STOP:
229okfn:
230 local_bh_disable();
231 entry->state.okfn(entry->state.net, entry->state.sk, skb);
232 local_bh_enable();
233 break;
234 case NF_QUEUE:
235 err = nf_queue(skb, &entry->state, &hook_entry, verdict);
236 if (err == 1) {
237 if (hook_entry)
238 goto next_hook;
239 goto okfn;
240 }
241 break;
242 case NF_STOLEN:
243 break;
244 default:
245 kfree_skb(skb);
246 }
247
248 kfree(entry);
249}
250EXPORT_SYMBOL(nf_reinject);
1/*
2 * Rusty Russell (C)2000 -- This code is GPL.
3 * Patrick McHardy (c) 2006-2012
4 */
5
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
24static const struct nf_queue_handler __rcu *nf_queue_handler;
25
26/*
27 * Hook for nfnetlink_queue to register its queue handler.
28 * We do this so that most of the NFQUEUE code can be modular.
29 *
30 * Once the queue is registered it must reinject all packets it
31 * receives, no matter what.
32 */
33
34void nf_register_queue_handler(const struct nf_queue_handler *qh)
35{
36 /* should never happen, we only have one queueing backend in kernel */
37 WARN_ON(rcu_access_pointer(nf_queue_handler));
38 rcu_assign_pointer(nf_queue_handler, qh);
39}
40EXPORT_SYMBOL(nf_register_queue_handler);
41
42/* The caller must flush their queue before this */
43void nf_unregister_queue_handler(void)
44{
45 RCU_INIT_POINTER(nf_queue_handler, NULL);
46}
47EXPORT_SYMBOL(nf_unregister_queue_handler);
48
49static void nf_queue_sock_put(struct sock *sk)
50{
51#ifdef CONFIG_INET
52 sock_gen_put(sk);
53#else
54 sock_put(sk);
55#endif
56}
57
58static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
59{
60 struct nf_hook_state *state = &entry->state;
61
62 /* Release those devices we held, or Alexey will kill me. */
63 dev_put(state->in);
64 dev_put(state->out);
65 if (state->sk)
66 nf_queue_sock_put(state->sk);
67
68#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
69 dev_put(entry->physin);
70 dev_put(entry->physout);
71#endif
72}
73
74void nf_queue_entry_free(struct nf_queue_entry *entry)
75{
76 nf_queue_entry_release_refs(entry);
77 kfree(entry);
78}
79EXPORT_SYMBOL_GPL(nf_queue_entry_free);
80
81static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry)
82{
83#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
84 const struct sk_buff *skb = entry->skb;
85 struct nf_bridge_info *nf_bridge;
86
87 nf_bridge = nf_bridge_info_get(skb);
88 if (nf_bridge) {
89 entry->physin = nf_bridge_get_physindev(skb);
90 entry->physout = nf_bridge_get_physoutdev(skb);
91 } else {
92 entry->physin = NULL;
93 entry->physout = NULL;
94 }
95#endif
96}
97
98/* Bump dev refs so they don't vanish while packet is out */
99bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
100{
101 struct nf_hook_state *state = &entry->state;
102
103 if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt))
104 return false;
105
106 dev_hold(state->in);
107 dev_hold(state->out);
108
109#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
110 dev_hold(entry->physin);
111 dev_hold(entry->physout);
112#endif
113 return true;
114}
115EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
116
117void nf_queue_nf_hook_drop(struct net *net)
118{
119 const struct nf_queue_handler *qh;
120
121 rcu_read_lock();
122 qh = rcu_dereference(nf_queue_handler);
123 if (qh)
124 qh->nf_hook_drop(net);
125 rcu_read_unlock();
126}
127EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
128
129static void nf_ip_saveroute(const struct sk_buff *skb,
130 struct nf_queue_entry *entry)
131{
132 struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
133
134 if (entry->state.hook == NF_INET_LOCAL_OUT) {
135 const struct iphdr *iph = ip_hdr(skb);
136
137 rt_info->tos = iph->tos;
138 rt_info->daddr = iph->daddr;
139 rt_info->saddr = iph->saddr;
140 rt_info->mark = skb->mark;
141 }
142}
143
144static void nf_ip6_saveroute(const struct sk_buff *skb,
145 struct nf_queue_entry *entry)
146{
147 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
148
149 if (entry->state.hook == NF_INET_LOCAL_OUT) {
150 const struct ipv6hdr *iph = ipv6_hdr(skb);
151
152 rt_info->daddr = iph->daddr;
153 rt_info->saddr = iph->saddr;
154 rt_info->mark = skb->mark;
155 }
156}
157
158static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
159 unsigned int index, unsigned int queuenum)
160{
161 struct nf_queue_entry *entry = NULL;
162 const struct nf_queue_handler *qh;
163 unsigned int route_key_size;
164 int status;
165
166 /* QUEUE == DROP if no one is waiting, to be safe. */
167 qh = rcu_dereference(nf_queue_handler);
168 if (!qh)
169 return -ESRCH;
170
171 switch (state->pf) {
172 case AF_INET:
173 route_key_size = sizeof(struct ip_rt_info);
174 break;
175 case AF_INET6:
176 route_key_size = sizeof(struct ip6_rt_info);
177 break;
178 default:
179 route_key_size = 0;
180 break;
181 }
182
183 if (skb_sk_is_prefetched(skb)) {
184 struct sock *sk = skb->sk;
185
186 if (!sk_is_refcounted(sk)) {
187 if (!refcount_inc_not_zero(&sk->sk_refcnt))
188 return -ENOTCONN;
189
190 /* drop refcount on skb_orphan */
191 skb->destructor = sock_edemux;
192 }
193 }
194
195 entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
196 if (!entry)
197 return -ENOMEM;
198
199 if (skb_dst(skb) && !skb_dst_force(skb)) {
200 kfree(entry);
201 return -ENETDOWN;
202 }
203
204 *entry = (struct nf_queue_entry) {
205 .skb = skb,
206 .state = *state,
207 .hook_index = index,
208 .size = sizeof(*entry) + route_key_size,
209 };
210
211 __nf_queue_entry_init_physdevs(entry);
212
213 if (!nf_queue_entry_get_refs(entry)) {
214 kfree(entry);
215 return -ENOTCONN;
216 }
217
218 switch (entry->state.pf) {
219 case AF_INET:
220 nf_ip_saveroute(skb, entry);
221 break;
222 case AF_INET6:
223 nf_ip6_saveroute(skb, entry);
224 break;
225 }
226
227 status = qh->outfn(entry, queuenum);
228 if (status < 0) {
229 nf_queue_entry_free(entry);
230 return status;
231 }
232
233 return 0;
234}
235
236/* Packets leaving via this function must come back through nf_reinject(). */
237int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
238 unsigned int index, unsigned int verdict)
239{
240 int ret;
241
242 ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
243 if (ret < 0) {
244 if (ret == -ESRCH &&
245 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
246 return 1;
247 kfree_skb(skb);
248 }
249
250 return 0;
251}
252EXPORT_SYMBOL_GPL(nf_queue);
253
254static unsigned int nf_iterate(struct sk_buff *skb,
255 struct nf_hook_state *state,
256 const struct nf_hook_entries *hooks,
257 unsigned int *index)
258{
259 const struct nf_hook_entry *hook;
260 unsigned int verdict, i = *index;
261
262 while (i < hooks->num_hook_entries) {
263 hook = &hooks->hooks[i];
264repeat:
265 verdict = nf_hook_entry_hookfn(hook, skb, state);
266 if (verdict != NF_ACCEPT) {
267 *index = i;
268 if (verdict != NF_REPEAT)
269 return verdict;
270 goto repeat;
271 }
272 i++;
273 }
274
275 *index = i;
276 return NF_ACCEPT;
277}
278
279static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
280{
281 switch (pf) {
282#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
283 case NFPROTO_BRIDGE:
284 return rcu_dereference(net->nf.hooks_bridge[hooknum]);
285#endif
286 case NFPROTO_IPV4:
287 return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
288 case NFPROTO_IPV6:
289 return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
290 default:
291 WARN_ON_ONCE(1);
292 return NULL;
293 }
294
295 return NULL;
296}
297
298/* Caller must hold rcu read-side lock */
299void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
300{
301 const struct nf_hook_entry *hook_entry;
302 const struct nf_hook_entries *hooks;
303 struct sk_buff *skb = entry->skb;
304 const struct net *net;
305 unsigned int i;
306 int err;
307 u8 pf;
308
309 net = entry->state.net;
310 pf = entry->state.pf;
311
312 hooks = nf_hook_entries_head(net, pf, entry->state.hook);
313
314 i = entry->hook_index;
315 if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
316 kfree_skb(skb);
317 nf_queue_entry_free(entry);
318 return;
319 }
320
321 hook_entry = &hooks->hooks[i];
322
323 /* Continue traversal iff userspace said ok... */
324 if (verdict == NF_REPEAT)
325 verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
326
327 if (verdict == NF_ACCEPT) {
328 if (nf_reroute(skb, entry) < 0)
329 verdict = NF_DROP;
330 }
331
332 if (verdict == NF_ACCEPT) {
333next_hook:
334 ++i;
335 verdict = nf_iterate(skb, &entry->state, hooks, &i);
336 }
337
338 switch (verdict & NF_VERDICT_MASK) {
339 case NF_ACCEPT:
340 case NF_STOP:
341 local_bh_disable();
342 entry->state.okfn(entry->state.net, entry->state.sk, skb);
343 local_bh_enable();
344 break;
345 case NF_QUEUE:
346 err = nf_queue(skb, &entry->state, i, verdict);
347 if (err == 1)
348 goto next_hook;
349 break;
350 case NF_STOLEN:
351 break;
352 default:
353 kfree_skb(skb);
354 }
355
356 nf_queue_entry_free(entry);
357}
358EXPORT_SYMBOL(nf_reinject);