Loading...
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
24/*
25 * Hook for nfnetlink_queue to register its queue handler.
26 * We do this so that most of the NFQUEUE code can be modular.
27 *
28 * Once the queue is registered it must reinject all packets it
29 * receives, no matter what.
30 */
31
32/* return EBUSY when somebody else is registered, return EEXIST if the
33 * same handler is registered, return 0 in case of success. */
34void nf_register_queue_handler(struct net *net, 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(net->nf.queue_handler));
38 rcu_assign_pointer(net->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(struct net *net)
44{
45 RCU_INIT_POINTER(net->nf.queue_handler, NULL);
46}
47EXPORT_SYMBOL(nf_unregister_queue_handler);
48
49static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
50{
51 struct nf_hook_state *state = &entry->state;
52
53 /* Release those devices we held, or Alexey will kill me. */
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
61#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
62 if (entry->physin)
63 dev_put(entry->physin);
64 if (entry->physout)
65 dev_put(entry->physout);
66#endif
67}
68
69void nf_queue_entry_free(struct nf_queue_entry *entry)
70{
71 nf_queue_entry_release_refs(entry);
72 kfree(entry);
73}
74EXPORT_SYMBOL_GPL(nf_queue_entry_free);
75
76static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry)
77{
78#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
79 const struct sk_buff *skb = entry->skb;
80 struct nf_bridge_info *nf_bridge;
81
82 nf_bridge = nf_bridge_info_get(skb);
83 if (nf_bridge) {
84 entry->physin = nf_bridge_get_physindev(skb);
85 entry->physout = nf_bridge_get_physoutdev(skb);
86 } else {
87 entry->physin = NULL;
88 entry->physout = NULL;
89 }
90#endif
91}
92
93/* Bump dev refs so they don't vanish while packet is out */
94void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
95{
96 struct nf_hook_state *state = &entry->state;
97
98 if (state->in)
99 dev_hold(state->in);
100 if (state->out)
101 dev_hold(state->out);
102 if (state->sk)
103 sock_hold(state->sk);
104
105#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
106 if (entry->physin)
107 dev_hold(entry->physin);
108 if (entry->physout)
109 dev_hold(entry->physout);
110#endif
111}
112EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
113
114void nf_queue_nf_hook_drop(struct net *net)
115{
116 const struct nf_queue_handler *qh;
117
118 rcu_read_lock();
119 qh = rcu_dereference(net->nf.queue_handler);
120 if (qh)
121 qh->nf_hook_drop(net);
122 rcu_read_unlock();
123}
124EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
125
126static void nf_ip_saveroute(const struct sk_buff *skb,
127 struct nf_queue_entry *entry)
128{
129 struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
130
131 if (entry->state.hook == NF_INET_LOCAL_OUT) {
132 const struct iphdr *iph = ip_hdr(skb);
133
134 rt_info->tos = iph->tos;
135 rt_info->daddr = iph->daddr;
136 rt_info->saddr = iph->saddr;
137 rt_info->mark = skb->mark;
138 }
139}
140
141static void nf_ip6_saveroute(const struct sk_buff *skb,
142 struct nf_queue_entry *entry)
143{
144 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
145
146 if (entry->state.hook == NF_INET_LOCAL_OUT) {
147 const struct ipv6hdr *iph = ipv6_hdr(skb);
148
149 rt_info->daddr = iph->daddr;
150 rt_info->saddr = iph->saddr;
151 rt_info->mark = skb->mark;
152 }
153}
154
155static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
156 unsigned int index, unsigned int queuenum)
157{
158 struct nf_queue_entry *entry = NULL;
159 const struct nf_queue_handler *qh;
160 struct net *net = state->net;
161 unsigned int route_key_size;
162 int status;
163
164 /* QUEUE == DROP if no one is waiting, to be safe. */
165 qh = rcu_dereference(net->nf.queue_handler);
166 if (!qh)
167 return -ESRCH;
168
169 switch (state->pf) {
170 case AF_INET:
171 route_key_size = sizeof(struct ip_rt_info);
172 break;
173 case AF_INET6:
174 route_key_size = sizeof(struct ip6_rt_info);
175 break;
176 default:
177 route_key_size = 0;
178 break;
179 }
180
181 entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
182 if (!entry)
183 return -ENOMEM;
184
185 if (skb_dst(skb) && !skb_dst_force(skb)) {
186 kfree(entry);
187 return -ENETDOWN;
188 }
189
190 *entry = (struct nf_queue_entry) {
191 .skb = skb,
192 .state = *state,
193 .hook_index = index,
194 .size = sizeof(*entry) + route_key_size,
195 };
196
197 __nf_queue_entry_init_physdevs(entry);
198
199 nf_queue_entry_get_refs(entry);
200
201 switch (entry->state.pf) {
202 case AF_INET:
203 nf_ip_saveroute(skb, entry);
204 break;
205 case AF_INET6:
206 nf_ip6_saveroute(skb, entry);
207 break;
208 }
209
210 status = qh->outfn(entry, queuenum);
211 if (status < 0) {
212 nf_queue_entry_free(entry);
213 return status;
214 }
215
216 return 0;
217}
218
219/* Packets leaving via this function must come back through nf_reinject(). */
220int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
221 unsigned int index, unsigned int verdict)
222{
223 int ret;
224
225 ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
226 if (ret < 0) {
227 if (ret == -ESRCH &&
228 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
229 return 1;
230 kfree_skb(skb);
231 }
232
233 return 0;
234}
235EXPORT_SYMBOL_GPL(nf_queue);
236
237static unsigned int nf_iterate(struct sk_buff *skb,
238 struct nf_hook_state *state,
239 const struct nf_hook_entries *hooks,
240 unsigned int *index)
241{
242 const struct nf_hook_entry *hook;
243 unsigned int verdict, i = *index;
244
245 while (i < hooks->num_hook_entries) {
246 hook = &hooks->hooks[i];
247repeat:
248 verdict = nf_hook_entry_hookfn(hook, skb, state);
249 if (verdict != NF_ACCEPT) {
250 *index = i;
251 if (verdict != NF_REPEAT)
252 return verdict;
253 goto repeat;
254 }
255 i++;
256 }
257
258 *index = i;
259 return NF_ACCEPT;
260}
261
262static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
263{
264 switch (pf) {
265#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
266 case NFPROTO_BRIDGE:
267 return rcu_dereference(net->nf.hooks_bridge[hooknum]);
268#endif
269 case NFPROTO_IPV4:
270 return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
271 case NFPROTO_IPV6:
272 return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
273 default:
274 WARN_ON_ONCE(1);
275 return NULL;
276 }
277
278 return NULL;
279}
280
281/* Caller must hold rcu read-side lock */
282void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
283{
284 const struct nf_hook_entry *hook_entry;
285 const struct nf_hook_entries *hooks;
286 struct sk_buff *skb = entry->skb;
287 const struct net *net;
288 unsigned int i;
289 int err;
290 u8 pf;
291
292 net = entry->state.net;
293 pf = entry->state.pf;
294
295 hooks = nf_hook_entries_head(net, pf, entry->state.hook);
296
297 i = entry->hook_index;
298 if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
299 kfree_skb(skb);
300 nf_queue_entry_free(entry);
301 return;
302 }
303
304 hook_entry = &hooks->hooks[i];
305
306 /* Continue traversal iff userspace said ok... */
307 if (verdict == NF_REPEAT)
308 verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
309
310 if (verdict == NF_ACCEPT) {
311 if (nf_reroute(skb, entry) < 0)
312 verdict = NF_DROP;
313 }
314
315 if (verdict == NF_ACCEPT) {
316next_hook:
317 ++i;
318 verdict = nf_iterate(skb, &entry->state, hooks, &i);
319 }
320
321 switch (verdict & NF_VERDICT_MASK) {
322 case NF_ACCEPT:
323 case NF_STOP:
324 local_bh_disable();
325 entry->state.okfn(entry->state.net, entry->state.sk, skb);
326 local_bh_enable();
327 break;
328 case NF_QUEUE:
329 err = nf_queue(skb, &entry->state, i, verdict);
330 if (err == 1)
331 goto next_hook;
332 break;
333 case NF_STOLEN:
334 break;
335 default:
336 kfree_skb(skb);
337 }
338
339 nf_queue_entry_free(entry);
340}
341EXPORT_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/seq_file.h>
14#include <linux/rcupdate.h>
15#include <net/protocol.h>
16#include <net/netfilter/nf_queue.h>
17#include <net/dst.h>
18
19#include "nf_internals.h"
20
21/*
22 * Hook for nfnetlink_queue to register its queue handler.
23 * We do this so that most of the NFQUEUE code can be modular.
24 *
25 * Once the queue is registered it must reinject all packets it
26 * receives, no matter what.
27 */
28static const struct nf_queue_handler __rcu *queue_handler __read_mostly;
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(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(queue_handler));
36 rcu_assign_pointer(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(void)
42{
43 RCU_INIT_POINTER(queue_handler, NULL);
44 synchronize_rcu();
45}
46EXPORT_SYMBOL(nf_unregister_queue_handler);
47
48void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
49{
50 /* Release those devices we held, or Alexey will kill me. */
51 if (entry->indev)
52 dev_put(entry->indev);
53 if (entry->outdev)
54 dev_put(entry->outdev);
55#ifdef CONFIG_BRIDGE_NETFILTER
56 if (entry->skb->nf_bridge) {
57 struct nf_bridge_info *nf_bridge = entry->skb->nf_bridge;
58
59 if (nf_bridge->physindev)
60 dev_put(nf_bridge->physindev);
61 if (nf_bridge->physoutdev)
62 dev_put(nf_bridge->physoutdev);
63 }
64#endif
65 /* Drop reference to owner of hook which queued us. */
66 module_put(entry->elem->owner);
67}
68EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs);
69
70/* Bump dev refs so they don't vanish while packet is out */
71bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
72{
73 if (!try_module_get(entry->elem->owner))
74 return false;
75
76 if (entry->indev)
77 dev_hold(entry->indev);
78 if (entry->outdev)
79 dev_hold(entry->outdev);
80#ifdef CONFIG_BRIDGE_NETFILTER
81 if (entry->skb->nf_bridge) {
82 struct nf_bridge_info *nf_bridge = entry->skb->nf_bridge;
83 struct net_device *physdev;
84
85 physdev = nf_bridge->physindev;
86 if (physdev)
87 dev_hold(physdev);
88 physdev = nf_bridge->physoutdev;
89 if (physdev)
90 dev_hold(physdev);
91 }
92#endif
93
94 return true;
95}
96EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
97
98/*
99 * Any packet that leaves via this function must come back
100 * through nf_reinject().
101 */
102int nf_queue(struct sk_buff *skb,
103 struct nf_hook_ops *elem,
104 u_int8_t pf, unsigned int hook,
105 struct net_device *indev,
106 struct net_device *outdev,
107 int (*okfn)(struct sk_buff *),
108 unsigned int queuenum)
109{
110 int status = -ENOENT;
111 struct nf_queue_entry *entry = NULL;
112 const struct nf_afinfo *afinfo;
113 const struct nf_queue_handler *qh;
114
115 /* QUEUE == DROP if no one is waiting, to be safe. */
116 rcu_read_lock();
117
118 qh = rcu_dereference(queue_handler);
119 if (!qh) {
120 status = -ESRCH;
121 goto err_unlock;
122 }
123
124 afinfo = nf_get_afinfo(pf);
125 if (!afinfo)
126 goto err_unlock;
127
128 entry = kmalloc(sizeof(*entry) + afinfo->route_key_size, GFP_ATOMIC);
129 if (!entry) {
130 status = -ENOMEM;
131 goto err_unlock;
132 }
133
134 *entry = (struct nf_queue_entry) {
135 .skb = skb,
136 .elem = elem,
137 .pf = pf,
138 .hook = hook,
139 .indev = indev,
140 .outdev = outdev,
141 .okfn = okfn,
142 .size = sizeof(*entry) + afinfo->route_key_size,
143 };
144
145 if (!nf_queue_entry_get_refs(entry)) {
146 status = -ECANCELED;
147 goto err_unlock;
148 }
149 skb_dst_force(skb);
150 afinfo->saveroute(skb, entry);
151 status = qh->outfn(entry, queuenum);
152
153 rcu_read_unlock();
154
155 if (status < 0) {
156 nf_queue_entry_release_refs(entry);
157 goto err;
158 }
159
160 return 0;
161
162err_unlock:
163 rcu_read_unlock();
164err:
165 kfree(entry);
166 return status;
167}
168
169void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
170{
171 struct sk_buff *skb = entry->skb;
172 struct nf_hook_ops *elem = entry->elem;
173 const struct nf_afinfo *afinfo;
174 int err;
175
176 rcu_read_lock();
177
178 nf_queue_entry_release_refs(entry);
179
180 /* Continue traversal iff userspace said ok... */
181 if (verdict == NF_REPEAT) {
182 elem = list_entry(elem->list.prev, struct nf_hook_ops, list);
183 verdict = NF_ACCEPT;
184 }
185
186 if (verdict == NF_ACCEPT) {
187 afinfo = nf_get_afinfo(entry->pf);
188 if (!afinfo || afinfo->reroute(skb, entry) < 0)
189 verdict = NF_DROP;
190 }
191
192 if (verdict == NF_ACCEPT) {
193 next_hook:
194 verdict = nf_iterate(&nf_hooks[entry->pf][entry->hook],
195 skb, entry->hook,
196 entry->indev, entry->outdev, &elem,
197 entry->okfn, INT_MIN);
198 }
199
200 switch (verdict & NF_VERDICT_MASK) {
201 case NF_ACCEPT:
202 case NF_STOP:
203 local_bh_disable();
204 entry->okfn(skb);
205 local_bh_enable();
206 break;
207 case NF_QUEUE:
208 err = nf_queue(skb, elem, entry->pf, entry->hook,
209 entry->indev, entry->outdev, entry->okfn,
210 verdict >> NF_VERDICT_QBITS);
211 if (err < 0) {
212 if (err == -ECANCELED)
213 goto next_hook;
214 if (err == -ESRCH &&
215 (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
216 goto next_hook;
217 kfree_skb(skb);
218 }
219 break;
220 case NF_STOLEN:
221 break;
222 default:
223 kfree_skb(skb);
224 }
225 rcu_read_unlock();
226 kfree(entry);
227}
228EXPORT_SYMBOL(nf_reinject);