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Commit 97a2d41c authored by Eric Leblond's avatar Eric Leblond Committed by Pablo Neira Ayuso
Browse files

netfilter: xt_NFQUEUE: separate reusable code 



This patch prepares the addition of nft_queue module by moving
reusable code into a header file.

This patch also converts NFQUEUE to use prandom_u32 to initialize
the random jhash seed as suggested by Florian Westphal.

Signed-off-by: default avatarEric Leblond <eric@regit.org>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent e569bdab

include/net/netfilter/nf_queue.h

+62 −0
Original line number Diff line number Diff line 
#ifndef _NF_QUEUE_H

#define _NF_QUEUE_H



#include <linux/ip.h>

#include <linux/ipv6.h>

#include <linux/jhash.h>



/* Each queued (to userspace) skbuff has one of these. */

struct nf_queue_entry {

	struct list_head	list;
@@ -33,4 +37,62 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict); 
bool nf_queue_entry_get_refs(struct nf_queue_entry *entry);

void nf_queue_entry_release_refs(struct nf_queue_entry *entry);



static inline void init_hashrandom(u32 *jhash_initval)

{

	while (*jhash_initval == 0)

		*jhash_initval = prandom_u32();

}



static inline u32 hash_v4(const struct sk_buff *skb, u32 jhash_initval)

{

	const struct iphdr *iph = ip_hdr(skb);



	/* packets in either direction go into same queue */

	if ((__force u32)iph->saddr < (__force u32)iph->daddr)

		return jhash_3words((__force u32)iph->saddr,

			(__force u32)iph->daddr, iph->protocol, jhash_initval);



	return jhash_3words((__force u32)iph->daddr,

			(__force u32)iph->saddr, iph->protocol, jhash_initval);

}



#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)

static inline u32 hash_v6(const struct sk_buff *skb, u32 jhash_initval)

{

	const struct ipv6hdr *ip6h = ipv6_hdr(skb);

	u32 a, b, c;



	if ((__force u32)ip6h->saddr.s6_addr32[3] <

	    (__force u32)ip6h->daddr.s6_addr32[3]) {

		a = (__force u32) ip6h->saddr.s6_addr32[3];

		b = (__force u32) ip6h->daddr.s6_addr32[3];

	} else {

		b = (__force u32) ip6h->saddr.s6_addr32[3];

		a = (__force u32) ip6h->daddr.s6_addr32[3];

	}



	if ((__force u32)ip6h->saddr.s6_addr32[1] <

	    (__force u32)ip6h->daddr.s6_addr32[1])

		c = (__force u32) ip6h->saddr.s6_addr32[1];

	else

		c = (__force u32) ip6h->daddr.s6_addr32[1];



	return jhash_3words(a, b, c, jhash_initval);

}

#endif



static inline u32

nfqueue_hash(const struct sk_buff *skb, u16 queue, u16 queues_total, u8 family,

	     u32 jhash_initval)

{

	if (family == NFPROTO_IPV4)

		queue += ((u64) hash_v4(skb, jhash_initval) * queues_total) >> 32;

#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)

	else if (family == NFPROTO_IPV6)

		queue += ((u64) hash_v6(skb, jhash_initval) * queues_total) >> 32;

#endif



	return queue;

}



#endif /* _NF_QUEUE_H */

net/netfilter/xt_NFQUEUE.c

+12 −68
Original line number Diff line number Diff line
@@ -11,15 +11,13 @@ 
#include <linux/module.h>

#include <linux/skbuff.h>



#include <linux/ip.h>

#include <linux/ipv6.h>

#include <linux/jhash.h>



#include <linux/netfilter.h>

#include <linux/netfilter_arp.h>

#include <linux/netfilter/x_tables.h>

#include <linux/netfilter/xt_NFQUEUE.h>



#include <net/netfilter/nf_queue.h>



MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");

MODULE_DESCRIPTION("Xtables: packet forwarding to netlink");

MODULE_LICENSE("GPL");
@@ -28,7 +26,6 @@ MODULE_ALIAS("ip6t_NFQUEUE"); 
MODULE_ALIAS("arpt_NFQUEUE");



static u32 jhash_initval __read_mostly;

static bool rnd_inited __read_mostly;



static unsigned int

nfqueue_tg(struct sk_buff *skb, const struct xt_action_param *par)
@@ -38,69 +35,16 @@ nfqueue_tg(struct sk_buff *skb, const struct xt_action_param *par) 
	return NF_QUEUE_NR(tinfo->queuenum);

}



static u32 hash_v4(const struct sk_buff *skb)

{

	const struct iphdr *iph = ip_hdr(skb);



	/* packets in either direction go into same queue */

	if ((__force u32)iph->saddr < (__force u32)iph->daddr)

		return jhash_3words((__force u32)iph->saddr,

			(__force u32)iph->daddr, iph->protocol, jhash_initval);



	return jhash_3words((__force u32)iph->daddr,

			(__force u32)iph->saddr, iph->protocol, jhash_initval);

}



#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)

static u32 hash_v6(const struct sk_buff *skb)

{

	const struct ipv6hdr *ip6h = ipv6_hdr(skb);

	u32 a, b, c;



	if ((__force u32)ip6h->saddr.s6_addr32[3] <

	    (__force u32)ip6h->daddr.s6_addr32[3]) {

		a = (__force u32) ip6h->saddr.s6_addr32[3];

		b = (__force u32) ip6h->daddr.s6_addr32[3];

	} else {

		b = (__force u32) ip6h->saddr.s6_addr32[3];

		a = (__force u32) ip6h->daddr.s6_addr32[3];

	}



	if ((__force u32)ip6h->saddr.s6_addr32[1] <

	    (__force u32)ip6h->daddr.s6_addr32[1])

		c = (__force u32) ip6h->saddr.s6_addr32[1];

	else

		c = (__force u32) ip6h->daddr.s6_addr32[1];



	return jhash_3words(a, b, c, jhash_initval);

}

#endif



static u32

nfqueue_hash(const struct sk_buff *skb, const struct xt_action_param *par)

{

	const struct xt_NFQ_info_v1 *info = par->targinfo;

	u32 queue = info->queuenum;



	if (par->family == NFPROTO_IPV4)

		queue += ((u64) hash_v4(skb) * info->queues_total) >> 32;

#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)

	else if (par->family == NFPROTO_IPV6)

		queue += ((u64) hash_v6(skb) * info->queues_total) >> 32;

#endif



	return queue;

}



static unsigned int

nfqueue_tg_v1(struct sk_buff *skb, const struct xt_action_param *par)

{

	const struct xt_NFQ_info_v1 *info = par->targinfo;

	u32 queue = info->queuenum;



	if (info->queues_total > 1)

		queue = nfqueue_hash(skb, par);



	if (info->queues_total > 1) {

		queue = nfqueue_hash(skb, queue, info->queues_total,

				     par->family, jhash_initval);

	}

	return NF_QUEUE_NR(queue);

}
@@ -120,10 +64,8 @@ static int nfqueue_tg_check(const struct xt_tgchk_param *par) 
	const struct xt_NFQ_info_v3 *info = par->targinfo;

	u32 maxid;



	if (unlikely(!rnd_inited)) {

		get_random_bytes(&jhash_initval, sizeof(jhash_initval));

		rnd_inited = true;

	}

	init_hashrandom(&jhash_initval);



	if (info->queues_total == 0) {

		pr_err("NFQUEUE: number of total queues is 0\n");

		return -EINVAL;
@@ -154,8 +96,10 @@ nfqueue_tg_v3(struct sk_buff *skb, const struct xt_action_param *par) 
			int cpu = smp_processor_id();



			queue = info->queuenum + cpu % info->queues_total;

		} else

			queue = nfqueue_hash(skb, par);

		} else {

			queue = nfqueue_hash(skb, queue, info->queues_total,

					     par->family, jhash_initval);

		}

	}



	ret = NF_QUEUE_NR(queue);