#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <net/protocol.h>
#include "nf_internals.h"
/*
* A queue handler may be registered for each protocol. Each is protected by
* long term mutex. The handler must provide an an outfn() to accept packets
* for queueing and must reinject all packets it receives, no matter what.
*/
static struct nf_queue_handler_t {
nf_queue_outfn_t outfn;
void *data;
} queue_handler[NPROTO];
static struct nf_queue_rerouter *queue_rerouter;
static DEFINE_RWLOCK(queue_handler_lock);
int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data)
{
int ret;
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
if (queue_handler[pf].outfn)
ret = -EBUSY;
else {
queue_handler[pf].outfn = outfn;
queue_handler[pf].data = data;
ret = 0;
}
write_unlock_bh(&queue_handler_lock);
return ret;
}
EXPORT_SYMBOL(nf_register_queue_handler);
/* The caller must flush their queue before this */
int nf_unregister_queue_handler(int pf)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
queue_handler[pf].outfn = NULL;
queue_handler[pf].data = NULL;
write_unlock_bh(&queue_handler_lock);
return 0;
}
EXPORT_SYMBOL(nf_unregister_queue_handler);
int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
memcpy(&queue_rerouter[pf], rer, sizeof(queue_rerouter[pf]));
write_unlock_bh(&queue_handler_lock);
return 0;
}
EXPORT_SYMBOL_GPL(nf_register_queue_rerouter);
int nf_unregister_queue_rerouter(int pf)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
memset(&queue_rerouter[pf], 0, sizeof(queue_rerouter[pf]));
write_unlock_bh(&queue_handler_lock);
return 0;
}
EXPORT_SYMBOL_GPL(nf_unregister_queue_rerouter);
void nf_unregister_queue_handlers(nf_queue_outfn_t outfn)
{
int pf;
write_lock_bh(&queue_handler_lock);
for (pf = 0; pf < NPROTO; pf++) {
if (queue_handler[pf].outfn == outfn) {
queue_handler[pf].outfn = NULL;
queue_handler[pf].data = NULL;
}
}
write_unlock_bh(&queue_handler_lock);
}
EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers);
/*
* Any packet that leaves via this function must come back
* through nf_reinject().
*/
int nf_queue(struct sk_buff **skb,
struct list_head *elem,
int pf, unsigned int hook,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *),
unsigned int queuenum)
{
int status;
struct nf_info *info;
#ifdef CONFIG_BRIDGE_NETFILTER
struct net_device *physindev = NULL;
struct net_device *physoutdev = NULL;
#endif
/* QUEUE == DROP if noone is waiting, to be safe. */
read_lock(&queue_handler_lock);
if (!queue_handler[pf].outfn) {
read_unlock(&queue_handler_lock);
kfree_skb(*skb);
return 1;
}
info = kmalloc(sizeof(*info)+queue_rerouter[pf].rer_size, GFP_ATOMIC);
if (!info) {
if (net_ratelimit())
printk(KERN_ERR "OOM queueing packet %p\n",
*skb);
read_unlock(&queue_handler_lock);
kfree_skb(*skb);
return 1;
}
*info = (struct nf_info) {
(struct nf_hook_ops *)elem, pf, hook, indev, outdev, okfn };
/* If it's going away, ignore hook. */
if (!try_module_get(info->elem->owner)) {
read_unlock(&queue_handler_lock);
kfree(info);
return 0;
}
/* Bump dev refs so they don't vanish while packet is out */
if (indev) dev_hold(indev);
if (outdev) dev_hold(outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if ((*skb)->nf_bridge) {
physindev = (*skb)->nf_bridge->physindev;
if (physindev) dev_hold(physindev);
physoutdev = (*skb)->nf_bridge->physoutdev;
if (physoutdev) dev_hold(physoutdev);
}
#endif
if (queue_rerouter[pf].save)
queue_rerouter[pf].save(*skb, info);
status = queue_handler[pf].outfn(*skb, info, queuenum,
queue_handler[pf].data);
if (status >= 0 && queue_rerouter[pf].reroute)
status = queue_rerouter[pf].reroute(skb, info);
read_unlock(&queue_handler_lock);
if (status < 0) {
/* James M doesn't say fuck enough. */
if (indev) dev_put(indev);
if (outdev) dev_put(outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if (physindev) dev_put(physindev);
if (physoutdev) dev_put(physoutdev);
#endif
module_put(info->elem->owner);
kfree(info);
kfree_skb(*skb);
return 1;
}
return 1;
}
void nf_reinject(struct sk_buff *skb, struct nf_info *info,
unsigned int verdict)
{
struct list_head *elem = &info->elem->list;
struct list_head *i;
rcu_read_lock();
/* Release those devices we held, or Alexey will kill me. */
if (info->indev) dev_put(info->indev);
if (info->outdev) dev_put(info->outdev);
#ifdef CONFIG_BRIDGE_NETFILTER
if (skb->nf_bridge) {
if (skb->nf_bridge->physindev)
dev_put(skb->nf_bridge->physindev);
if (skb->nf_bridge->physoutdev)
dev_put(skb->nf_bridge->physoutdev);
}
#endif
/* Drop reference to owner of hook which queued us. */
module_put(info->elem->owner);
list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) {
if (i == elem)
break;
}
if (elem == &nf_hooks[info->pf][info->hook]) {
/* The module which sent it to userspace is gone. */
NFDEBUG("%s: module disappeared, dropping packet.\n",
__FUNCTION__);
verdict = NF_DROP;
}
/* Continue traversal iff userspace said ok... */
if (verdict == NF_REPEAT) {
elem = elem->prev;
verdict = NF_ACCEPT;
}
if (verdict == NF_ACCEPT) {
next_hook:
verdict = nf_iterate(&nf_hooks[info->pf][info->hook],
&skb, info->hook,
info->indev, info->outdev, &elem,
info->okfn, INT_MIN);
}
switch (verdict & NF_VERDICT_MASK) {
case NF_ACCEPT:
info->okfn(skb);
break;
case NF_QUEUE:
if (!nf_queue(&skb, elem, info->pf, info->hook,
info->indev, info->outdev, info->okfn,
verdict >> NF_VERDICT_BITS))
goto next_hook;
break;
}
rcu_read_unlock();
if (verdict == NF_DROP)
kfree_skb(skb);
kfree(info);
return;
}
EXPORT_SYMBOL(nf_reinject);
int __init netfilter_queue_init(void)
{
queue_rerouter = kmalloc(NPROTO * sizeof(struct nf_queue_rerouter),
GFP_KERNEL);
if (!queue_rerouter)
return -ENOMEM;
memset(queue_rerouter, 0, NPROTO * sizeof(struct nf_queue_rerouter));
return 0;
}
