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netfilter: xt_NFQUEUE: separate reusable code

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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: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Eric Leblond 2013-12-06 00:24:12 +01:00 committed by Pablo Neira Ayuso
parent e569bdab35
commit 97a2d41c47
2 changed files with 74 additions and 68 deletions
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62
include/net/netfilter/nf_queue.h
View File

@ -1,6 +1,10 @@
#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 */

80
net/netfilter/xt_NFQUEUE.c
View File

@ -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);