Release 4.16 net/netfilter/nf_queue.c

/*
 * Rusty Russell (C)2000 -- This code is GPL.
 * Patrick McHardy (c) 2006-2012
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter_bridge.h>
#include <linux/seq_file.h>
#include <linux/rcupdate.h>
#include <net/protocol.h>
#include <net/netfilter/nf_queue.h>
#include <net/dst.h>

#include "nf_internals.h"

/*
 * Hook for nfnetlink_queue to register its queue handler.
 * We do this so that most of the NFQUEUE code can be modular.
 *
 * Once the queue is registered it must reinject all packets it
 * receives, no matter what.
 */

/* return EBUSY when somebody else is registered, return EEXIST if the
 * same handler is registered, return 0 in case of success. */


void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh)
{
	/* should never happen, we only have one queueing backend in kernel */
	WARN_ON(rcu_access_pointer(net->nf.queue_handler));
	rcu_assign_pointer(net->nf.queue_handler, qh);
}
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Eric Dumazet
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12.50%
2
25.00%
Florian Westphal
4
10.00%
1
12.50%
Yasuyuki Kozakai
3
7.50%
1
12.50%
Patrick McHardy
1
2.50%
1
12.50%
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40
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8
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EXPORT_SYMBOL(nf_register_queue_handler);

/* The caller must flush their queue before this */


void nf_unregister_queue_handler(struct net *net)
{
	RCU_INIT_POINTER(net->nf.queue_handler, NULL);
}
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3
14.29%
1
20.00%
Stephen Hemminger
1
4.76%
1
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Florian Westphal
1
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EXPORT_SYMBOL(nf_unregister_queue_handler);



void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
{
	struct nf_hook_state *state = &entry->state;

	/* Release those devices we held, or Alexey will kill me. */
	if (state->in)
		dev_put(state->in);
	if (state->out)
		dev_put(state->out);
	if (state->sk)
		sock_put(state->sk);
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
	if (entry->skb->nf_bridge) {
		struct net_device *physdev;

		physdev = nf_bridge_get_physindev(entry->skb);
		if (physdev)
			dev_put(physdev);
		physdev = nf_bridge_get_physoutdev(entry->skb);
		if (physdev)
			dev_put(physdev);
	}
#endif
}
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24.37%
2
40.00%
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21
17.65%
1
20.00%
Pablo Neira Ayuso
5
4.20%
1
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119
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5
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EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs);

/* Bump dev refs so they don't vanish while packet is out */


void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
{
	struct nf_hook_state *state = &entry->state;

	if (state->in)
		dev_hold(state->in);
	if (state->out)
		dev_hold(state->out);
	if (state->sk)
		sock_hold(state->sk);
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
	if (entry->skb->nf_bridge) {
		struct net_device *physdev;

		physdev = nf_bridge_get_physindev(entry->skb);
		if (physdev)
			dev_hold(physdev);
		physdev = nf_bridge_get_physoutdev(entry->skb);
		if (physdev)
			dev_hold(physdev);
	}
#endif
}
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4.24%
1
16.67%
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6
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EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);



void nf_queue_nf_hook_drop(struct net *net)
{
	const struct nf_queue_handler *qh;

	rcu_read_lock();
	qh = rcu_dereference(net->nf.queue_handler);
	if (qh)
		qh->nf_hook_drop(net);
	rcu_read_unlock();
}
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6.82%
1
25.00%
Florian Westphal
1
2.27%
1
25.00%
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44
100.00%
4
100.00%

EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);



static void nf_ip_saveroute(const struct sk_buff *skb,
			    struct nf_queue_entry *entry)
{
	struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);

	if (entry->state.hook == NF_INET_LOCAL_OUT) {
		const struct iphdr *iph = ip_hdr(skb);

		rt_info->tos = iph->tos;
		rt_info->daddr = iph->daddr;
		rt_info->saddr = iph->saddr;
		rt_info->mark = skb->mark;
	}
}

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static void nf_ip6_saveroute(const struct sk_buff *skb,
			     struct nf_queue_entry *entry)
{
	struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);

	if (entry->state.hook == NF_INET_LOCAL_OUT) {
		const struct ipv6hdr *iph = ipv6_hdr(skb);

		rt_info->daddr = iph->daddr;
		rt_info->saddr = iph->saddr;
		rt_info->mark = skb->mark;
	}
}

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static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
		      const struct nf_hook_entries *entries,
		      unsigned int index, unsigned int queuenum)
{
	int status = -ENOENT;
	struct nf_queue_entry *entry = NULL;
	const struct nf_queue_handler *qh;
	struct net *net = state->net;
	unsigned int route_key_size;

	/* QUEUE == DROP if no one is waiting, to be safe. */
	qh = rcu_dereference(net->nf.queue_handler);
	if (!qh) {
		status = -ESRCH;
		goto err;
	}

	switch (state->pf) {
	case AF_INET:
		route_key_size = sizeof(struct ip_rt_info);
		break;
	case AF_INET6:
		route_key_size = sizeof(struct ip6_rt_info);
		break;
	default:
		route_key_size = 0;
		break;
	}

	entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
	if (!entry) {
		status = -ENOMEM;
		goto err;
	}

	*entry = (struct nf_queue_entry) {
		.skb	= skb,
		.state	= *state,
		.hook_index = index,
		.size	= sizeof(*entry) + route_key_size,
        };

	nf_queue_entry_get_refs(entry);
	skb_dst_force(skb);

	switch (entry->state.pf) {
	case AF_INET:
		nf_ip_saveroute(skb, entry);
		break;
	case AF_INET6:
		nf_ip6_saveroute(skb, entry);
		break;
	}

	status = qh->outfn(entry, queuenum);

	if (status < 0) {
		nf_queue_entry_release_refs(entry);
		goto err;
	}

	return 0;

err:
	kfree(entry);
	return status;
}

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16.00%
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42
15.22%
6
24.00%
Florian Westphal
34
12.32%
6
24.00%
Eric W. Biedermann
13
4.71%
1
4.00%
Yasuyuki Kozakai
10
3.62%
1
4.00%
Aaron Conole
9
3.26%
1
4.00%
David S. Miller
7
2.54%
2
8.00%
Eric Dumazet
5
1.81%
1
4.00%
Lucas De Marchi
1
0.36%
1
4.00%
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25
100.00%

/* Packets leaving via this function must come back through nf_reinject(). */


int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
	     const struct nf_hook_entries *entries, unsigned int index,
	     unsigned int verdict)
{
	int ret;

	ret = __nf_queue(skb, state, entries, index, verdict >> NF_VERDICT_QBITS);
	if (ret < 0) {
		if (ret == -ESRCH &&
		    (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
			return 1;
		kfree_skb(skb);
	}

	return 0;
}

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3
100.00%



static unsigned int nf_iterate(struct sk_buff *skb,
			       struct nf_hook_state *state,
			       const struct nf_hook_entries *hooks,
			       unsigned int *index)
{
	const struct nf_hook_entry *hook;
	unsigned int verdict, i = *index;

	while (i < hooks->num_hook_entries) {
		hook = &hooks->hooks[i];
repeat:
		verdict = nf_hook_entry_hookfn(hook, skb, state);
		if (verdict != NF_ACCEPT) {
			if (verdict != NF_REPEAT)
				return verdict;
			goto repeat;
		}
		i++;
	}

	*index = i;
	return NF_ACCEPT;
}

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107
100.00%
3
100.00%



static struct nf_hook_entries *nf_hook_entries_head(const struct net *net, u8 pf, u8 hooknum)
{
	switch (pf) {
#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
	case NFPROTO_BRIDGE:
		return rcu_dereference(net->nf.hooks_bridge[hooknum]);
#endif
	case NFPROTO_IPV4:
		return rcu_dereference(net->nf.hooks_ipv4[hooknum]);
	case NFPROTO_IPV6:
		return rcu_dereference(net->nf.hooks_ipv6[hooknum]);
	default:
		WARN_ON_ONCE(1);
		return NULL;
	}

	return NULL;
}

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/* Caller must hold rcu read-side lock */


void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
{
	const struct nf_hook_entry *hook_entry;
	const struct nf_hook_entries *hooks;
	struct sk_buff *skb = entry->skb;
	const struct net *net;
	unsigned int i;
	int err;
	u8 pf;

	net = entry->state.net;
	pf = entry->state.pf;

	hooks = nf_hook_entries_head(net, pf, entry->state.hook);

	nf_queue_entry_release_refs(entry);

	i = entry->hook_index;
	if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) {
		kfree_skb(skb);
		kfree(entry);
		return;
	}

	hook_entry = &hooks->hooks[i];

	/* Continue traversal iff userspace said ok... */
	if (verdict == NF_REPEAT)
		verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);

	if (verdict == NF_ACCEPT) {
		if (nf_reroute(skb, entry) < 0)
			verdict = NF_DROP;
	}

	if (verdict == NF_ACCEPT) {
next_hook:
		++i;
		verdict = nf_iterate(skb, &entry->state, hooks, &i);
	}

	switch (verdict & NF_VERDICT_MASK) {
	case NF_ACCEPT:
	case NF_STOP:
		local_bh_disable();
		entry->state.okfn(entry->state.net, entry->state.sk, skb);
		local_bh_enable();
		break;
	case NF_QUEUE:
		err = nf_queue(skb, &entry->state, hooks, i, verdict);
		if (err == 1)
			goto next_hook;
		break;
	case NF_STOLEN:
		break;
	default:
		kfree_skb(skb);
	}

	kfree(entry);
}
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30.14%
1
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44
15.07%
6
23.08%
Florian Westphal
26
8.90%
6
23.08%
David S. Miller
12
4.11%
3
11.54%
Eric W. Biedermann
6
2.05%
1
3.85%
Pablo Neira Ayuso
6
2.05%
3
11.54%
Michael Wang
4
1.37%
1
3.85%
Eric Dumazet
3
1.03%
1
3.85%
Julian Anastasov
1
0.34%
1
3.85%
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292
100.00%
26
100.00%

EXPORT_SYMBOL(nf_reinject);
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14.29%
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19.72%
14
25.00%
Harald Welte
238
16.64%
3
5.36%
Aaron Conole
166
11.61%
3
5.36%
Patrick McHardy
158
11.05%
11
19.64%
Eric W. Biedermann
80
5.59%
3
5.36%
David S. Miller
77
5.38%
4
7.14%
Eric Dumazet
16
1.12%
4
7.14%
Yasuyuki Kozakai
16
1.12%
1
1.79%
Michael Wang
4
0.28%
1
1.79%
Tejun Heo
3
0.21%
1
1.79%
Lucas De Marchi
1
0.07%
1
1.79%
Julian Anastasov
1
0.07%
1
1.79%
Stephen Hemminger
1
0.07%
1
1.79%
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1430
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56
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Directory: net/netfilter

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