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netfilter: bridge: add and use br_nf_hook_thresh

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This replaces the last uses of NF_HOOK_THRESH().
Followup patch will remove it and rename nf_hook_thresh.

The reason is that inet (non-bridge) netfilter no longer invokes the
hooks from hooks, so we do no longer need the thresh value to skip hooks
with a lower priority.

The bridge netfilter however may need to do this. br_nf_hook_thresh is a
wrapper that is supposed to do this, i.e. only call hooks with a
priority that exceeds NF_BR_PRI_BRNF.

It's used only in the recursion cases of br_netfilter.  It invokes
nf_hook_slow while holding an rcu read-side critical section to make a
future cleanup simpler.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2016-09-21 11:35:01 -04:00 committed by Pablo Neira Ayuso
parent 50f4c7b73f
commit c5136b15ea
3 changed files with 62 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/net/netfilter/br_netfilter.h
View File

@ -15,6 +15,12 @@ static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
void nf_bridge_update_protocol(struct sk_buff *skb);
int br_nf_hook_thresh(unsigned int hook, struct net *net, struct sock *sk,
struct sk_buff *skb, struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct net *, struct sock *,
struct sk_buff *));
static inline struct nf_bridge_info *
nf_bridge_info_get(const struct sk_buff *skb)
{

60
net/bridge/br_netfilter_hooks.c
View File

@ -30,6 +30,7 @@
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter_arp.h>
#include <linux/in_route.h>
#include <linux/rculist.h>
#include <linux/inetdevice.h>
#include <net/ip.h>
@ -395,11 +396,10 @@ bridged_dnat:
skb->dev = nf_bridge->physindev;
nf_bridge_update_protocol(skb);
nf_bridge_push_encap_header(skb);
NF_HOOK_THRESH(NFPROTO_BRIDGE,
NF_BR_PRE_ROUTING,
net, sk, skb, skb->dev, NULL,
br_nf_pre_routing_finish_bridge,
1);
br_nf_hook_thresh(NF_BR_PRE_ROUTING,
net, sk, skb, skb->dev,
NULL,
br_nf_pre_routing_finish);
return 0;
}
ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
@ -417,10 +417,8 @@ bridged_dnat:
skb->dev = nf_bridge->physindev;
nf_bridge_update_protocol(skb);
nf_bridge_push_encap_header(skb);
NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, net, sk, skb,
skb->dev, NULL,
br_handle_frame_finish, 1);
br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb, skb->dev, NULL,
br_handle_frame_finish);
return 0;
}
@ -992,6 +990,50 @@ static struct notifier_block brnf_notifier __read_mostly = {
.notifier_call = brnf_device_event,
};
/* recursively invokes nf_hook_slow (again), skipping already-called
* hooks (< NF_BR_PRI_BRNF).
*
* Called with rcu read lock held.
*/
int br_nf_hook_thresh(unsigned int hook, struct net *net,
struct sock *sk, struct sk_buff *skb,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct net *, struct sock *,
struct sk_buff *))
{
struct nf_hook_ops *elem;
struct nf_hook_state state;
struct list_head *head;
int ret;
head = &net->nf.hooks[NFPROTO_BRIDGE][hook];
list_for_each_entry_rcu(elem, head, list) {
struct nf_hook_ops *next;
next = list_entry_rcu(list_next_rcu(&elem->list),
struct nf_hook_ops, list);
if (next->priority <= NF_BR_PRI_BRNF)
continue;
}
if (&elem->list == head)
return okfn(net, sk, skb);
/* We may already have this, but read-locks nest anyway */
rcu_read_lock();
nf_hook_state_init(&state, head, hook, NF_BR_PRI_BRNF + 1,
NFPROTO_BRIDGE, indev, outdev, sk, net, okfn);
ret = nf_hook_slow(skb, &state);
rcu_read_unlock();
if (ret == 1)
ret = okfn(net, sk, skb);
return ret;
}
#ifdef CONFIG_SYSCTL
static
int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,

12
net/bridge/br_netfilter_ipv6.c
View File

@ -187,10 +187,9 @@ static int br_nf_pre_routing_finish_ipv6(struct net *net, struct sock *sk, struc
skb->dev = nf_bridge->physindev;
nf_bridge_update_protocol(skb);
nf_bridge_push_encap_header(skb);
NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
net, sk, skb, skb->dev, NULL,
br_nf_pre_routing_finish_bridge,
1);
br_nf_hook_thresh(NF_BR_PRE_ROUTING,
net, sk, skb, skb->dev, NULL,
br_nf_pre_routing_finish_bridge);
return 0;
}
ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
@ -207,9 +206,8 @@ static int br_nf_pre_routing_finish_ipv6(struct net *net, struct sock *sk, struc
skb->dev = nf_bridge->physindev;
nf_bridge_update_protocol(skb);
nf_bridge_push_encap_header(skb);
NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, net, sk, skb,
skb->dev, NULL,
br_handle_frame_finish, 1);
br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb,
skb->dev, NULL, br_handle_frame_finish);
return 0;
}