ia64/linux-2.6.18-xen.hg

view net/netfilter/core.c @ 871:9cbcc9008446

xen/x86: don't initialize cpu_data[]'s apicid field on generic code

Afaict, this is not only redundant with the intialization done in
drivers/xen/core/smpboot.c, but actually results - at least for
secondary CPUs - in the Xen-specific value written to be later
overwritten with whatever the generic code determines (with no
guarantee that the two values are identical).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu May 14 10:09:15 2009 +0100 (2009-05-14)
parents 831230e53067
children
line source
1 /* netfilter.c: look after the filters for various protocols.
2 * Heavily influenced by the old firewall.c by David Bonn and Alan Cox.
3 *
4 * Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
5 * way.
6 *
7 * Rusty Russell (C)2000 -- This code is GPL.
8 *
9 * February 2000: Modified by James Morris to have 1 queue per protocol.
10 * 15-Mar-2000: Added NF_REPEAT --RR.
11 * 08-May-2003: Internal logging interface added by Jozsef Kadlecsik.
12 */
13 #include <linux/kernel.h>
14 #include <linux/netfilter.h>
15 #include <net/protocol.h>
16 #include <linux/init.h>
17 #include <linux/skbuff.h>
18 #include <linux/wait.h>
19 #include <linux/module.h>
20 #include <linux/interrupt.h>
21 #include <linux/if.h>
22 #include <linux/netdevice.h>
23 #include <linux/inetdevice.h>
24 #include <linux/proc_fs.h>
25 #include <net/sock.h>
27 #include "nf_internals.h"
29 static DEFINE_SPINLOCK(afinfo_lock);
31 struct nf_afinfo *nf_afinfo[NPROTO];
32 EXPORT_SYMBOL(nf_afinfo);
34 int nf_register_afinfo(struct nf_afinfo *afinfo)
35 {
36 spin_lock(&afinfo_lock);
37 rcu_assign_pointer(nf_afinfo[afinfo->family], afinfo);
38 spin_unlock(&afinfo_lock);
39 return 0;
40 }
41 EXPORT_SYMBOL_GPL(nf_register_afinfo);
43 void nf_unregister_afinfo(struct nf_afinfo *afinfo)
44 {
45 spin_lock(&afinfo_lock);
46 rcu_assign_pointer(nf_afinfo[afinfo->family], NULL);
47 spin_unlock(&afinfo_lock);
48 synchronize_rcu();
49 }
50 EXPORT_SYMBOL_GPL(nf_unregister_afinfo);
52 /* In this code, we can be waiting indefinitely for userspace to
53 * service a packet if a hook returns NF_QUEUE. We could keep a count
54 * of skbuffs queued for userspace, and not deregister a hook unless
55 * this is zero, but that sucks. Now, we simply check when the
56 * packets come back: if the hook is gone, the packet is discarded. */
57 struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
58 EXPORT_SYMBOL(nf_hooks);
59 static DEFINE_SPINLOCK(nf_hook_lock);
61 int nf_register_hook(struct nf_hook_ops *reg)
62 {
63 struct list_head *i;
65 spin_lock_bh(&nf_hook_lock);
66 list_for_each(i, &nf_hooks[reg->pf][reg->hooknum]) {
67 if (reg->priority < ((struct nf_hook_ops *)i)->priority)
68 break;
69 }
70 list_add_rcu(&reg->list, i->prev);
71 spin_unlock_bh(&nf_hook_lock);
73 synchronize_net();
74 return 0;
75 }
76 EXPORT_SYMBOL(nf_register_hook);
78 void nf_unregister_hook(struct nf_hook_ops *reg)
79 {
80 spin_lock_bh(&nf_hook_lock);
81 list_del_rcu(&reg->list);
82 spin_unlock_bh(&nf_hook_lock);
84 synchronize_net();
85 }
86 EXPORT_SYMBOL(nf_unregister_hook);
88 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n)
89 {
90 unsigned int i;
91 int err = 0;
93 for (i = 0; i < n; i++) {
94 err = nf_register_hook(&reg[i]);
95 if (err)
96 goto err;
97 }
98 return err;
100 err:
101 if (i > 0)
102 nf_unregister_hooks(reg, i);
103 return err;
104 }
105 EXPORT_SYMBOL(nf_register_hooks);
107 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
108 {
109 unsigned int i;
111 for (i = 0; i < n; i++)
112 nf_unregister_hook(&reg[i]);
113 }
114 EXPORT_SYMBOL(nf_unregister_hooks);
116 unsigned int nf_iterate(struct list_head *head,
117 struct sk_buff **skb,
118 int hook,
119 const struct net_device *indev,
120 const struct net_device *outdev,
121 struct list_head **i,
122 int (*okfn)(struct sk_buff *),
123 int hook_thresh)
124 {
125 unsigned int verdict;
127 /*
128 * The caller must not block between calls to this
129 * function because of risk of continuing from deleted element.
130 */
131 list_for_each_continue_rcu(*i, head) {
132 struct nf_hook_ops *elem = (struct nf_hook_ops *)*i;
134 if (hook_thresh > elem->priority)
135 continue;
137 /* Optimization: we don't need to hold module
138 reference here, since function can't sleep. --RR */
139 verdict = elem->hook(hook, skb, indev, outdev, okfn);
140 if (verdict != NF_ACCEPT) {
141 #ifdef CONFIG_NETFILTER_DEBUG
142 if (unlikely((verdict & NF_VERDICT_MASK)
143 > NF_MAX_VERDICT)) {
144 NFDEBUG("Evil return from %p(%u).\n",
145 elem->hook, hook);
146 continue;
147 }
148 #endif
149 if (verdict != NF_REPEAT)
150 return verdict;
151 *i = (*i)->prev;
152 }
153 }
154 return NF_ACCEPT;
155 }
158 /* Returns 1 if okfn() needs to be executed by the caller,
159 * -EPERM for NF_DROP, 0 otherwise. */
160 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
161 struct net_device *indev,
162 struct net_device *outdev,
163 int (*okfn)(struct sk_buff *),
164 int hook_thresh)
165 {
166 struct list_head *elem;
167 unsigned int verdict;
168 int ret = 0;
170 /* We may already have this, but read-locks nest anyway */
171 rcu_read_lock();
173 elem = &nf_hooks[pf][hook];
174 next_hook:
175 verdict = nf_iterate(&nf_hooks[pf][hook], pskb, hook, indev,
176 outdev, &elem, okfn, hook_thresh);
177 if (verdict == NF_ACCEPT || verdict == NF_STOP) {
178 ret = 1;
179 goto unlock;
180 } else if (verdict == NF_DROP) {
181 kfree_skb(*pskb);
182 ret = -EPERM;
183 } else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
184 NFDEBUG("nf_hook: Verdict = QUEUE.\n");
185 if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn,
186 verdict >> NF_VERDICT_BITS))
187 goto next_hook;
188 }
189 unlock:
190 rcu_read_unlock();
191 return ret;
192 }
193 EXPORT_SYMBOL(nf_hook_slow);
196 int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len)
197 {
198 struct sk_buff *nskb;
200 if (writable_len > (*pskb)->len)
201 return 0;
203 /* Not exclusive use of packet? Must copy. */
204 if (skb_shared(*pskb) || skb_cloned(*pskb))
205 goto copy_skb;
207 return pskb_may_pull(*pskb, writable_len);
209 copy_skb:
210 nskb = skb_copy(*pskb, GFP_ATOMIC);
211 if (!nskb)
212 return 0;
213 BUG_ON(skb_is_nonlinear(nskb));
215 /* Rest of kernel will get very unhappy if we pass it a
216 suddenly-orphaned skbuff */
217 if ((*pskb)->sk)
218 skb_set_owner_w(nskb, (*pskb)->sk);
219 kfree_skb(*pskb);
220 *pskb = nskb;
221 return 1;
222 }
223 EXPORT_SYMBOL(skb_make_writable);
226 /* This does not belong here, but locally generated errors need it if connection
227 tracking in use: without this, connection may not be in hash table, and hence
228 manufactured ICMP or RST packets will not be associated with it. */
229 void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
230 EXPORT_SYMBOL(ip_ct_attach);
232 void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb)
233 {
234 void (*attach)(struct sk_buff *, struct sk_buff *);
236 if (skb->nfct && (attach = ip_ct_attach) != NULL) {
237 mb(); /* Just to be sure: must be read before executing this */
238 attach(new, skb);
239 }
240 }
241 EXPORT_SYMBOL(nf_ct_attach);
243 #ifdef CONFIG_PROC_FS
244 struct proc_dir_entry *proc_net_netfilter;
245 EXPORT_SYMBOL(proc_net_netfilter);
246 #endif
248 void __init netfilter_init(void)
249 {
250 int i, h;
251 for (i = 0; i < NPROTO; i++) {
252 for (h = 0; h < NF_MAX_HOOKS; h++)
253 INIT_LIST_HEAD(&nf_hooks[i][h]);
254 }
256 #ifdef CONFIG_PROC_FS
257 proc_net_netfilter = proc_mkdir("netfilter", proc_net);
258 if (!proc_net_netfilter)
259 panic("cannot create netfilter proc entry");
260 #endif
262 if (netfilter_queue_init() < 0)
263 panic("cannot initialize nf_queue");
264 if (netfilter_log_init() < 0)
265 panic("cannot initialize nf_log");
266 }