--- /dev/null
+/* netfilter.c: look after the filters for various protocols.
+ * Heavily influenced by the old firewall.c by David Bonn and Alan Cox.
+ *
+ * Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
+ * way.
+ *
+ * Rusty Russell (C)2000 -- This code is GPL.
+ *
+ * February 2000: Modified by James Morris to have 1 queue per protocol.
+ * 15-Mar-2000: Added NF_REPEAT --RR.
+ * 08-May-2003: Internal logging interface added by Jozsef Kadlecsik.
+ */
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/netfilter.h>
+#include <net/protocol.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/if.h>
+#include <linux/netdevice.h>
+#include <linux/inetdevice.h>
+#include <linux/proc_fs.h>
+#include <net/sock.h>
+
+#include "nf_internals.h"
+
+static DEFINE_SPINLOCK(afinfo_lock);
+
+struct nf_afinfo *nf_afinfo[NPROTO];
+EXPORT_SYMBOL(nf_afinfo);
+
+int nf_register_afinfo(struct nf_afinfo *afinfo)
+{
+ spin_lock(&afinfo_lock);
+ rcu_assign_pointer(nf_afinfo[afinfo->family], afinfo);
+ spin_unlock(&afinfo_lock);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nf_register_afinfo);
+
+void nf_unregister_afinfo(struct nf_afinfo *afinfo)
+{
+ spin_lock(&afinfo_lock);
+ rcu_assign_pointer(nf_afinfo[afinfo->family], NULL);
+ spin_unlock(&afinfo_lock);
+ synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(nf_unregister_afinfo);
+
+/* In this code, we can be waiting indefinitely for userspace to
+ * service a packet if a hook returns NF_QUEUE. We could keep a count
+ * of skbuffs queued for userspace, and not deregister a hook unless
+ * this is zero, but that sucks. Now, we simply check when the
+ * packets come back: if the hook is gone, the packet is discarded. */
+struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
+EXPORT_SYMBOL(nf_hooks);
+static DEFINE_SPINLOCK(nf_hook_lock);
+
+int nf_register_hook(struct nf_hook_ops *reg)
+{
+ struct list_head *i;
+
+ spin_lock_bh(&nf_hook_lock);
+ list_for_each(i, &nf_hooks[reg->pf][reg->hooknum]) {
+ if (reg->priority < ((struct nf_hook_ops *)i)->priority)
+ break;
+ }
+ list_add_rcu(®->list, i->prev);
+ spin_unlock_bh(&nf_hook_lock);
+
+ synchronize_net();
+ return 0;
+}
+EXPORT_SYMBOL(nf_register_hook);
+
+void nf_unregister_hook(struct nf_hook_ops *reg)
+{
+ spin_lock_bh(&nf_hook_lock);
+ list_del_rcu(®->list);
+ spin_unlock_bh(&nf_hook_lock);
+
+ synchronize_net();
+}
+EXPORT_SYMBOL(nf_unregister_hook);
+
+int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n)
+{
+ unsigned int i;
+ int err = 0;
+
+ for (i = 0; i < n; i++) {
+ err = nf_register_hook(®[i]);
+ if (err)
+ goto err;
+ }
+ return err;
+
+err:
+ if (i > 0)
+ nf_unregister_hooks(reg, i);
+ return err;
+}
+EXPORT_SYMBOL(nf_register_hooks);
+
+void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
+{
+ unsigned int i;
+
+ for (i = 0; i < n; i++)
+ nf_unregister_hook(®[i]);
+}
+EXPORT_SYMBOL(nf_unregister_hooks);
+
+unsigned int nf_iterate(struct list_head *head,
+ struct sk_buff **skb,
+ int hook,
+ const struct net_device *indev,
+ const struct net_device *outdev,
+ struct list_head **i,
+ int (*okfn)(struct sk_buff *),
+ int hook_thresh)
+{
+ unsigned int verdict;
+
+ /*
+ * The caller must not block between calls to this
+ * function because of risk of continuing from deleted element.
+ */
+ list_for_each_continue_rcu(*i, head) {
+ struct nf_hook_ops *elem = (struct nf_hook_ops *)*i;
+
+ if (hook_thresh > elem->priority)
+ continue;
+
+ /* Optimization: we don't need to hold module
+ reference here, since function can't sleep. --RR */
+ verdict = elem->hook(hook, skb, indev, outdev, okfn);
+ if (verdict != NF_ACCEPT) {
+#ifdef CONFIG_NETFILTER_DEBUG
+ if (unlikely((verdict & NF_VERDICT_MASK)
+ > NF_MAX_VERDICT)) {
+ NFDEBUG("Evil return from %p(%u).\n",
+ elem->hook, hook);
+ continue;
+ }
+#endif
+ if (verdict != NF_REPEAT)
+ return verdict;
+ *i = (*i)->prev;
+ }
+ }
+ return NF_ACCEPT;
+}
+
+
+/* Returns 1 if okfn() needs to be executed by the caller,
+ * -EPERM for NF_DROP, 0 otherwise. */
+int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
+ struct net_device *indev,
+ struct net_device *outdev,
+ int (*okfn)(struct sk_buff *),
+ int hook_thresh)
+{
+ struct list_head *elem;
+ unsigned int verdict;
+ int ret = 0;
+
+ /* We may already have this, but read-locks nest anyway */
+ rcu_read_lock();
+
+ elem = &nf_hooks[pf][hook];
+next_hook:
+ verdict = nf_iterate(&nf_hooks[pf][hook], pskb, hook, indev,
+ outdev, &elem, okfn, hook_thresh);
+ if (verdict == NF_ACCEPT || verdict == NF_STOP) {
+ ret = 1;
+ goto unlock;
+ } else if (verdict == NF_DROP) {
+ kfree_skb(*pskb);
+ ret = -EPERM;
+ } else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
+ NFDEBUG("nf_hook: Verdict = QUEUE.\n");
+ if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn,
+ verdict >> NF_VERDICT_BITS))
+ goto next_hook;
+ }
+unlock:
+ rcu_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL(nf_hook_slow);
+
+
+int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len)
+{
+ struct sk_buff *nskb;
+
+ if (writable_len > (*pskb)->len)
+ return 0;
+
+ /* Not exclusive use of packet? Must copy. */
+ if (skb_shared(*pskb) || skb_cloned(*pskb))
+ goto copy_skb;
+
+ return pskb_may_pull(*pskb, writable_len);
+
+copy_skb:
+ nskb = skb_copy(*pskb, GFP_ATOMIC);
+ if (!nskb)
+ return 0;
+ BUG_ON(skb_is_nonlinear(nskb));
+
+ /* Rest of kernel will get very unhappy if we pass it a
+ suddenly-orphaned skbuff */
+ if ((*pskb)->sk)
+ skb_set_owner_w(nskb, (*pskb)->sk);
+ kfree_skb(*pskb);
+ *pskb = nskb;
+ return 1;
+}
+EXPORT_SYMBOL(skb_make_writable);
+
+
+/* This does not belong here, but locally generated errors need it if connection
+ tracking in use: without this, connection may not be in hash table, and hence
+ manufactured ICMP or RST packets will not be associated with it. */
+void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
+EXPORT_SYMBOL(ip_ct_attach);
+
+void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb)
+{
+ void (*attach)(struct sk_buff *, struct sk_buff *);
+
+ if (skb->nfct && (attach = ip_ct_attach) != NULL) {
+ mb(); /* Just to be sure: must be read before executing this */
+ attach(new, skb);
+ }
+}
+EXPORT_SYMBOL(nf_ct_attach);
+
+#ifdef CONFIG_PROC_FS
+struct proc_dir_entry *proc_net_netfilter;
+EXPORT_SYMBOL(proc_net_netfilter);
+#endif
+
+void __init netfilter_init(void)
+{
+ int i, h;
+ for (i = 0; i < NPROTO; i++) {
+ for (h = 0; h < NF_MAX_HOOKS; h++)
+ INIT_LIST_HEAD(&nf_hooks[i][h]);
+ }
+
+#ifdef CONFIG_PROC_FS
+ proc_net_netfilter = proc_mkdir("netfilter", proc_net);
+ if (!proc_net_netfilter)
+ panic("cannot create netfilter proc entry");
+#endif
+
+ if (netfilter_queue_init() < 0)
+ panic("cannot initialize nf_queue");
+ if (netfilter_log_init() < 0)
+ panic("cannot initialize nf_log");
+}
git://git.onelab.eu / linux-2.6.git / blobdiff