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Message-Id: <1474844823-2026-38-git-send-email-pablo@netfilter.org>
Date: Mon, 26 Sep 2016 01:06:47 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 37/53] netfilter: bridge: add and use br_nf_hook_thresh
From: Florian Westphal <fw@...len.de>
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@...len.de>
Signed-off-by: Aaron Conole <aconole@...heb.org>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/br_netfilter.h | 6 ++++
net/bridge/br_netfilter_hooks.c | 60 ++++++++++++++++++++++++++++++------
net/bridge/br_netfilter_ipv6.c | 12 +++-----
3 files changed, 62 insertions(+), 16 deletions(-)
diff --git a/include/net/netfilter/br_netfilter.h b/include/net/netfilter/br_netfilter.h
index e8d1448425a7..0b0c35c37125 100644
--- a/include/net/netfilter/br_netfilter.h
+++ b/include/net/netfilter/br_netfilter.h
@@ -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)
{
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 77e7f69bf80d..6029af47377d 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -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,
diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c
index 5e59a8457e7b..5989661c659f 100644
--- a/net/bridge/br_netfilter_ipv6.c
+++ b/net/bridge/br_netfilter_ipv6.c
@@ -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;
}
--
2.1.4
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