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f6ebe77f HW |
1 | #include <linux/kernel.h> |
2 | #include <linux/init.h> | |
3 | #include <linux/module.h> | |
4 | #include <linux/proc_fs.h> | |
5 | #include <linux/skbuff.h> | |
6 | #include <linux/netfilter.h> | |
bbd86b9f | 7 | #include <linux/seq_file.h> |
7a11b984 | 8 | #include <linux/rcupdate.h> |
f6ebe77f HW |
9 | #include <net/protocol.h> |
10 | ||
11 | #include "nf_internals.h" | |
12 | ||
13 | /* | |
14 | * A queue handler may be registered for each protocol. Each is protected by | |
15 | * long term mutex. The handler must provide an an outfn() to accept packets | |
16 | * for queueing and must reinject all packets it receives, no matter what. | |
17 | */ | |
bbd86b9f | 18 | static struct nf_queue_handler *queue_handler[NPROTO]; |
f6ebe77f HW |
19 | |
20 | static DEFINE_RWLOCK(queue_handler_lock); | |
21 | ||
d72367b6 HW |
22 | /* return EBUSY when somebody else is registered, return EEXIST if the |
23 | * same handler is registered, return 0 in case of success. */ | |
bbd86b9f | 24 | int nf_register_queue_handler(int pf, struct nf_queue_handler *qh) |
f6ebe77f HW |
25 | { |
26 | int ret; | |
27 | ||
28 | if (pf >= NPROTO) | |
29 | return -EINVAL; | |
30 | ||
31 | write_lock_bh(&queue_handler_lock); | |
d72367b6 HW |
32 | if (queue_handler[pf] == qh) |
33 | ret = -EEXIST; | |
34 | else if (queue_handler[pf]) | |
f6ebe77f HW |
35 | ret = -EBUSY; |
36 | else { | |
bbd86b9f | 37 | queue_handler[pf] = qh; |
f6ebe77f HW |
38 | ret = 0; |
39 | } | |
40 | write_unlock_bh(&queue_handler_lock); | |
41 | ||
42 | return ret; | |
43 | } | |
44 | EXPORT_SYMBOL(nf_register_queue_handler); | |
45 | ||
46 | /* The caller must flush their queue before this */ | |
47 | int nf_unregister_queue_handler(int pf) | |
48 | { | |
49 | if (pf >= NPROTO) | |
50 | return -EINVAL; | |
51 | ||
52 | write_lock_bh(&queue_handler_lock); | |
bbd86b9f | 53 | queue_handler[pf] = NULL; |
f6ebe77f HW |
54 | write_unlock_bh(&queue_handler_lock); |
55 | ||
56 | return 0; | |
57 | } | |
58 | EXPORT_SYMBOL(nf_unregister_queue_handler); | |
59 | ||
bbd86b9f | 60 | void nf_unregister_queue_handlers(struct nf_queue_handler *qh) |
f6ebe77f HW |
61 | { |
62 | int pf; | |
63 | ||
64 | write_lock_bh(&queue_handler_lock); | |
65 | for (pf = 0; pf < NPROTO; pf++) { | |
bbd86b9f HW |
66 | if (queue_handler[pf] == qh) |
67 | queue_handler[pf] = NULL; | |
f6ebe77f HW |
68 | } |
69 | write_unlock_bh(&queue_handler_lock); | |
70 | } | |
71 | EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers); | |
72 | ||
73 | /* | |
74 | * Any packet that leaves via this function must come back | |
75 | * through nf_reinject(). | |
76 | */ | |
394f545d PM |
77 | static int __nf_queue(struct sk_buff *skb, |
78 | struct list_head *elem, | |
79 | int pf, unsigned int hook, | |
80 | struct net_device *indev, | |
81 | struct net_device *outdev, | |
82 | int (*okfn)(struct sk_buff *), | |
83 | unsigned int queuenum) | |
f6ebe77f HW |
84 | { |
85 | int status; | |
86 | struct nf_info *info; | |
87 | #ifdef CONFIG_BRIDGE_NETFILTER | |
88 | struct net_device *physindev = NULL; | |
89 | struct net_device *physoutdev = NULL; | |
90 | #endif | |
bce8032e | 91 | struct nf_afinfo *afinfo; |
f6ebe77f HW |
92 | |
93 | /* QUEUE == DROP if noone is waiting, to be safe. */ | |
94 | read_lock(&queue_handler_lock); | |
e121e9ec | 95 | if (!queue_handler[pf]) { |
f6ebe77f | 96 | read_unlock(&queue_handler_lock); |
394f545d | 97 | kfree_skb(skb); |
f6ebe77f HW |
98 | return 1; |
99 | } | |
100 | ||
bce8032e PM |
101 | afinfo = nf_get_afinfo(pf); |
102 | if (!afinfo) { | |
103 | read_unlock(&queue_handler_lock); | |
394f545d | 104 | kfree_skb(skb); |
bce8032e PM |
105 | return 1; |
106 | } | |
107 | ||
108 | info = kmalloc(sizeof(*info) + afinfo->route_key_size, GFP_ATOMIC); | |
f6ebe77f HW |
109 | if (!info) { |
110 | if (net_ratelimit()) | |
111 | printk(KERN_ERR "OOM queueing packet %p\n", | |
394f545d | 112 | skb); |
f6ebe77f | 113 | read_unlock(&queue_handler_lock); |
394f545d | 114 | kfree_skb(skb); |
f6ebe77f HW |
115 | return 1; |
116 | } | |
117 | ||
118 | *info = (struct nf_info) { | |
119 | (struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn }; | |
120 | ||
121 | /* If it's going away, ignore hook. */ | |
122 | if (!try_module_get(info->elem->owner)) { | |
123 | read_unlock(&queue_handler_lock); | |
124 | kfree(info); | |
125 | return 0; | |
126 | } | |
127 | ||
128 | /* Bump dev refs so they don't vanish while packet is out */ | |
129 | if (indev) dev_hold(indev); | |
130 | if (outdev) dev_hold(outdev); | |
131 | ||
132 | #ifdef CONFIG_BRIDGE_NETFILTER | |
394f545d PM |
133 | if (skb->nf_bridge) { |
134 | physindev = skb->nf_bridge->physindev; | |
f6ebe77f | 135 | if (physindev) dev_hold(physindev); |
394f545d | 136 | physoutdev = skb->nf_bridge->physoutdev; |
f6ebe77f HW |
137 | if (physoutdev) dev_hold(physoutdev); |
138 | } | |
139 | #endif | |
394f545d PM |
140 | afinfo->saveroute(skb, info); |
141 | status = queue_handler[pf]->outfn(skb, info, queuenum, | |
bbd86b9f | 142 | queue_handler[pf]->data); |
f6ebe77f | 143 | |
f6ebe77f HW |
144 | read_unlock(&queue_handler_lock); |
145 | ||
146 | if (status < 0) { | |
147 | /* James M doesn't say fuck enough. */ | |
148 | if (indev) dev_put(indev); | |
149 | if (outdev) dev_put(outdev); | |
150 | #ifdef CONFIG_BRIDGE_NETFILTER | |
151 | if (physindev) dev_put(physindev); | |
152 | if (physoutdev) dev_put(physoutdev); | |
153 | #endif | |
154 | module_put(info->elem->owner); | |
155 | kfree(info); | |
394f545d | 156 | kfree_skb(skb); |
f6ebe77f HW |
157 | |
158 | return 1; | |
159 | } | |
160 | ||
161 | return 1; | |
162 | } | |
163 | ||
394f545d PM |
164 | int nf_queue(struct sk_buff *skb, |
165 | struct list_head *elem, | |
166 | int pf, unsigned int hook, | |
167 | struct net_device *indev, | |
168 | struct net_device *outdev, | |
169 | int (*okfn)(struct sk_buff *), | |
170 | unsigned int queuenum) | |
171 | { | |
172 | struct sk_buff *segs; | |
173 | ||
174 | if (!skb_is_gso(skb)) | |
175 | return __nf_queue(skb, elem, pf, hook, indev, outdev, okfn, | |
176 | queuenum); | |
177 | ||
178 | switch (pf) { | |
179 | case AF_INET: | |
180 | skb->protocol = htons(ETH_P_IP); | |
181 | break; | |
182 | case AF_INET6: | |
183 | skb->protocol = htons(ETH_P_IPV6); | |
184 | break; | |
185 | } | |
186 | ||
187 | segs = skb_gso_segment(skb, 0); | |
188 | kfree_skb(skb); | |
189 | if (unlikely(IS_ERR(segs))) | |
190 | return 1; | |
191 | ||
192 | do { | |
193 | struct sk_buff *nskb = segs->next; | |
194 | ||
195 | segs->next = NULL; | |
196 | if (!__nf_queue(segs, elem, pf, hook, indev, outdev, okfn, | |
197 | queuenum)) | |
198 | kfree_skb(segs); | |
199 | segs = nskb; | |
200 | } while (segs); | |
201 | return 1; | |
202 | } | |
203 | ||
f6ebe77f HW |
204 | void nf_reinject(struct sk_buff *skb, struct nf_info *info, |
205 | unsigned int verdict) | |
206 | { | |
207 | struct list_head *elem = &info->elem->list; | |
208 | struct list_head *i; | |
bce8032e | 209 | struct nf_afinfo *afinfo; |
f6ebe77f HW |
210 | |
211 | rcu_read_lock(); | |
212 | ||
213 | /* Release those devices we held, or Alexey will kill me. */ | |
214 | if (info->indev) dev_put(info->indev); | |
215 | if (info->outdev) dev_put(info->outdev); | |
216 | #ifdef CONFIG_BRIDGE_NETFILTER | |
217 | if (skb->nf_bridge) { | |
218 | if (skb->nf_bridge->physindev) | |
219 | dev_put(skb->nf_bridge->physindev); | |
220 | if (skb->nf_bridge->physoutdev) | |
221 | dev_put(skb->nf_bridge->physoutdev); | |
222 | } | |
223 | #endif | |
224 | ||
225 | /* Drop reference to owner of hook which queued us. */ | |
226 | module_put(info->elem->owner); | |
227 | ||
228 | list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) { | |
229 | if (i == elem) | |
230 | break; | |
231 | } | |
232 | ||
45fe4dc0 | 233 | if (i == &nf_hooks[info->pf][info->hook]) { |
f6ebe77f HW |
234 | /* The module which sent it to userspace is gone. */ |
235 | NFDEBUG("%s: module disappeared, dropping packet.\n", | |
236 | __FUNCTION__); | |
237 | verdict = NF_DROP; | |
238 | } | |
239 | ||
240 | /* Continue traversal iff userspace said ok... */ | |
241 | if (verdict == NF_REPEAT) { | |
242 | elem = elem->prev; | |
243 | verdict = NF_ACCEPT; | |
244 | } | |
245 | ||
7a11b984 | 246 | if (verdict == NF_ACCEPT) { |
bce8032e PM |
247 | afinfo = nf_get_afinfo(info->pf); |
248 | if (!afinfo || afinfo->reroute(&skb, info) < 0) | |
7a11b984 PM |
249 | verdict = NF_DROP; |
250 | } | |
251 | ||
f6ebe77f HW |
252 | if (verdict == NF_ACCEPT) { |
253 | next_hook: | |
254 | verdict = nf_iterate(&nf_hooks[info->pf][info->hook], | |
255 | &skb, info->hook, | |
256 | info->indev, info->outdev, &elem, | |
257 | info->okfn, INT_MIN); | |
258 | } | |
259 | ||
260 | switch (verdict & NF_VERDICT_MASK) { | |
261 | case NF_ACCEPT: | |
3bc38712 | 262 | case NF_STOP: |
f6ebe77f | 263 | info->okfn(skb); |
3bc38712 | 264 | case NF_STOLEN: |
f6ebe77f | 265 | break; |
f6ebe77f | 266 | case NF_QUEUE: |
394f545d PM |
267 | if (!__nf_queue(skb, elem, info->pf, info->hook, |
268 | info->indev, info->outdev, info->okfn, | |
269 | verdict >> NF_VERDICT_BITS)) | |
f6ebe77f HW |
270 | goto next_hook; |
271 | break; | |
3bc38712 PM |
272 | default: |
273 | kfree_skb(skb); | |
f6ebe77f HW |
274 | } |
275 | rcu_read_unlock(); | |
f6ebe77f HW |
276 | kfree(info); |
277 | return; | |
278 | } | |
279 | EXPORT_SYMBOL(nf_reinject); | |
280 | ||
bbd86b9f HW |
281 | #ifdef CONFIG_PROC_FS |
282 | static void *seq_start(struct seq_file *seq, loff_t *pos) | |
283 | { | |
284 | if (*pos >= NPROTO) | |
285 | return NULL; | |
286 | ||
287 | return pos; | |
288 | } | |
289 | ||
290 | static void *seq_next(struct seq_file *s, void *v, loff_t *pos) | |
291 | { | |
292 | (*pos)++; | |
293 | ||
294 | if (*pos >= NPROTO) | |
295 | return NULL; | |
296 | ||
297 | return pos; | |
298 | } | |
299 | ||
300 | static void seq_stop(struct seq_file *s, void *v) | |
301 | { | |
302 | ||
303 | } | |
304 | ||
305 | static int seq_show(struct seq_file *s, void *v) | |
306 | { | |
307 | int ret; | |
308 | loff_t *pos = v; | |
309 | struct nf_queue_handler *qh; | |
310 | ||
311 | read_lock_bh(&queue_handler_lock); | |
312 | qh = queue_handler[*pos]; | |
313 | if (!qh) | |
314 | ret = seq_printf(s, "%2lld NONE\n", *pos); | |
315 | else | |
316 | ret = seq_printf(s, "%2lld %s\n", *pos, qh->name); | |
317 | read_unlock_bh(&queue_handler_lock); | |
318 | ||
319 | return ret; | |
320 | } | |
321 | ||
322 | static struct seq_operations nfqueue_seq_ops = { | |
323 | .start = seq_start, | |
324 | .next = seq_next, | |
325 | .stop = seq_stop, | |
326 | .show = seq_show, | |
327 | }; | |
328 | ||
329 | static int nfqueue_open(struct inode *inode, struct file *file) | |
330 | { | |
331 | return seq_open(file, &nfqueue_seq_ops); | |
332 | } | |
333 | ||
334 | static struct file_operations nfqueue_file_ops = { | |
335 | .owner = THIS_MODULE, | |
336 | .open = nfqueue_open, | |
337 | .read = seq_read, | |
338 | .llseek = seq_lseek, | |
339 | .release = seq_release, | |
340 | }; | |
341 | #endif /* PROC_FS */ | |
342 | ||
343 | ||
f6ebe77f HW |
344 | int __init netfilter_queue_init(void) |
345 | { | |
bbd86b9f HW |
346 | #ifdef CONFIG_PROC_FS |
347 | struct proc_dir_entry *pde; | |
f6ebe77f | 348 | |
bbd86b9f | 349 | pde = create_proc_entry("nf_queue", S_IRUGO, proc_net_netfilter); |
e02f7d16 | 350 | if (!pde) |
bbd86b9f | 351 | return -1; |
bbd86b9f HW |
352 | pde->proc_fops = &nfqueue_file_ops; |
353 | #endif | |
f6ebe77f HW |
354 | return 0; |
355 | } | |
356 |