Remove obsolete #include <linux/config.h>
[linux-2.6.git] / net / netfilter / nf_queue.c
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>
7 #include <linux/seq_file.h>
8 #include <linux/rcupdate.h>
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  */
18 static struct nf_queue_handler *queue_handler[NPROTO];
19
20 static DEFINE_RWLOCK(queue_handler_lock);
21
22 /* return EBUSY when somebody else is registered, return EEXIST if the
23  * same handler is registered, return 0 in case of success. */
24 int nf_register_queue_handler(int pf, struct nf_queue_handler *qh)
25 {      
26         int ret;
27
28         if (pf >= NPROTO)
29                 return -EINVAL;
30
31         write_lock_bh(&queue_handler_lock);
32         if (queue_handler[pf] == qh)
33                 ret = -EEXIST;
34         else if (queue_handler[pf])
35                 ret = -EBUSY;
36         else {
37                 queue_handler[pf] = qh;
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);
53         queue_handler[pf] = NULL;
54         write_unlock_bh(&queue_handler_lock);
55         
56         return 0;
57 }
58 EXPORT_SYMBOL(nf_unregister_queue_handler);
59
60 void nf_unregister_queue_handlers(struct nf_queue_handler *qh)
61 {
62         int pf;
63
64         write_lock_bh(&queue_handler_lock);
65         for (pf = 0; pf < NPROTO; pf++)  {
66                 if (queue_handler[pf] == qh)
67                         queue_handler[pf] = NULL;
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  */
77 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)
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
91         struct nf_afinfo *afinfo;
92
93         /* QUEUE == DROP if noone is waiting, to be safe. */
94         read_lock(&queue_handler_lock);
95         if (!queue_handler[pf]) {
96                 read_unlock(&queue_handler_lock);
97                 kfree_skb(*skb);
98                 return 1;
99         }
100
101         afinfo = nf_get_afinfo(pf);
102         if (!afinfo) {
103                 read_unlock(&queue_handler_lock);
104                 kfree_skb(*skb);
105                 return 1;
106         }
107
108         info = kmalloc(sizeof(*info) + afinfo->route_key_size, GFP_ATOMIC);
109         if (!info) {
110                 if (net_ratelimit())
111                         printk(KERN_ERR "OOM queueing packet %p\n",
112                                *skb);
113                 read_unlock(&queue_handler_lock);
114                 kfree_skb(*skb);
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
133         if ((*skb)->nf_bridge) {
134                 physindev = (*skb)->nf_bridge->physindev;
135                 if (physindev) dev_hold(physindev);
136                 physoutdev = (*skb)->nf_bridge->physoutdev;
137                 if (physoutdev) dev_hold(physoutdev);
138         }
139 #endif
140         afinfo->saveroute(*skb, info);
141         status = queue_handler[pf]->outfn(*skb, info, queuenum,
142                                           queue_handler[pf]->data);
143
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);
156                 kfree_skb(*skb);
157
158                 return 1;
159         }
160
161         return 1;
162 }
163
164 void nf_reinject(struct sk_buff *skb, struct nf_info *info,
165                  unsigned int verdict)
166 {
167         struct list_head *elem = &info->elem->list;
168         struct list_head *i;
169         struct nf_afinfo *afinfo;
170
171         rcu_read_lock();
172
173         /* Release those devices we held, or Alexey will kill me. */
174         if (info->indev) dev_put(info->indev);
175         if (info->outdev) dev_put(info->outdev);
176 #ifdef CONFIG_BRIDGE_NETFILTER
177         if (skb->nf_bridge) {
178                 if (skb->nf_bridge->physindev)
179                         dev_put(skb->nf_bridge->physindev);
180                 if (skb->nf_bridge->physoutdev)
181                         dev_put(skb->nf_bridge->physoutdev);
182         }
183 #endif
184
185         /* Drop reference to owner of hook which queued us. */
186         module_put(info->elem->owner);
187
188         list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) {
189                 if (i == elem) 
190                         break;
191         }
192   
193         if (i == &nf_hooks[info->pf][info->hook]) {
194                 /* The module which sent it to userspace is gone. */
195                 NFDEBUG("%s: module disappeared, dropping packet.\n",
196                         __FUNCTION__);
197                 verdict = NF_DROP;
198         }
199
200         /* Continue traversal iff userspace said ok... */
201         if (verdict == NF_REPEAT) {
202                 elem = elem->prev;
203                 verdict = NF_ACCEPT;
204         }
205
206         if (verdict == NF_ACCEPT) {
207                 afinfo = nf_get_afinfo(info->pf);
208                 if (!afinfo || afinfo->reroute(&skb, info) < 0)
209                         verdict = NF_DROP;
210         }
211
212         if (verdict == NF_ACCEPT) {
213         next_hook:
214                 verdict = nf_iterate(&nf_hooks[info->pf][info->hook],
215                                      &skb, info->hook, 
216                                      info->indev, info->outdev, &elem,
217                                      info->okfn, INT_MIN);
218         }
219
220         switch (verdict & NF_VERDICT_MASK) {
221         case NF_ACCEPT:
222                 info->okfn(skb);
223                 break;
224
225         case NF_QUEUE:
226                 if (!nf_queue(&skb, elem, info->pf, info->hook, 
227                               info->indev, info->outdev, info->okfn,
228                               verdict >> NF_VERDICT_BITS))
229                         goto next_hook;
230                 break;
231         }
232         rcu_read_unlock();
233
234         if (verdict == NF_DROP)
235                 kfree_skb(skb);
236
237         kfree(info);
238         return;
239 }
240 EXPORT_SYMBOL(nf_reinject);
241
242 #ifdef CONFIG_PROC_FS
243 static void *seq_start(struct seq_file *seq, loff_t *pos)
244 {
245         if (*pos >= NPROTO)
246                 return NULL;
247
248         return pos;
249 }
250
251 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
252 {
253         (*pos)++;
254
255         if (*pos >= NPROTO)
256                 return NULL;
257
258         return pos;
259 }
260
261 static void seq_stop(struct seq_file *s, void *v)
262 {
263
264 }
265
266 static int seq_show(struct seq_file *s, void *v)
267 {
268         int ret;
269         loff_t *pos = v;
270         struct nf_queue_handler *qh;
271
272         read_lock_bh(&queue_handler_lock);
273         qh = queue_handler[*pos];
274         if (!qh)
275                 ret = seq_printf(s, "%2lld NONE\n", *pos);
276         else
277                 ret = seq_printf(s, "%2lld %s\n", *pos, qh->name);
278         read_unlock_bh(&queue_handler_lock);
279
280         return ret;
281 }
282
283 static struct seq_operations nfqueue_seq_ops = {
284         .start  = seq_start,
285         .next   = seq_next,
286         .stop   = seq_stop,
287         .show   = seq_show,
288 };
289
290 static int nfqueue_open(struct inode *inode, struct file *file)
291 {
292         return seq_open(file, &nfqueue_seq_ops);
293 }
294
295 static struct file_operations nfqueue_file_ops = {
296         .owner   = THIS_MODULE,
297         .open    = nfqueue_open,
298         .read    = seq_read,
299         .llseek  = seq_lseek,
300         .release = seq_release,
301 };
302 #endif /* PROC_FS */
303
304
305 int __init netfilter_queue_init(void)
306 {
307 #ifdef CONFIG_PROC_FS
308         struct proc_dir_entry *pde;
309
310         pde = create_proc_entry("nf_queue", S_IRUGO, proc_net_netfilter);
311         if (!pde)
312                 return -1;
313         pde->proc_fops = &nfqueue_file_ops;
314 #endif
315         return 0;
316 }
317