e5de75b ("netfilter: bridge: move DNAT helper to br_netfilter") results
in the following link problem:
net/bridge/br_device.c:29: undefined reference to `br_nf_prerouting_finish_bridge`
Moreover it creates a hard dependency between br_netfilter and the
bridge core, which is what we've been trying to avoid so far.
Resolve this problem by using a hook structure so we reduce #ifdef
pollution and keep bridge netfilter specific code under br_netfilter.c
which was the original intention.
Reported-by: Simon Horman <simon.horman@xxxxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/bridge/br_device.c | 7 ++++++-
net/bridge/br_netfilter.c | 9 +++++++--
net/bridge/br_private.h | 10 +++++-----
3 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 294cbcc..4ff77a1 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -25,6 +25,9 @@
#define COMMON_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA | \
NETIF_F_GSO_MASK | NETIF_F_HW_CSUM)
+const struct nf_br_ops __rcu *nf_br_ops __read_mostly;
+EXPORT_SYMBOL_GPL(nf_br_ops);
+
/* net device transmit always called with BH disabled */
netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
@@ -33,10 +36,12 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
struct net_bridge_fdb_entry *dst;
struct net_bridge_mdb_entry *mdst;
struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
+ const struct nf_br_ops *nf_ops;
u16 vid = 0;
rcu_read_lock();
- if (br_nf_prerouting_finish_bridge(skb)) {
+ nf_ops = rcu_dereference(nf_br_ops);
+ if (nf_ops && nf_ops->br_dev_xmit_hook(skb)) {
rcu_read_unlock();
return NETDEV_TX_OK;
}
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index a8361c7..b260a97 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -914,7 +914,7 @@ static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
br_handle_frame_finish(skb);
}
-int br_nf_prerouting_finish_bridge(struct sk_buff *skb)
+static int br_nf_dev_xmit(struct sk_buff *skb)
{
if (skb->nf_bridge && (skb->nf_bridge->mask & BRNF_BRIDGED_DNAT)) {
br_nf_pre_routing_finish_bridge_slow(skb);
@@ -922,7 +922,10 @@ int br_nf_prerouting_finish_bridge(struct sk_buff *skb)
}
return 0;
}
-EXPORT_SYMBOL_GPL(br_nf_prerouting_finish_bridge);
+
+static const struct nf_br_ops br_ops = {
+ .br_dev_xmit_hook = br_nf_dev_xmit,
+};
void br_netfilter_enable(void)
{
@@ -1061,12 +1064,14 @@ static int __init br_netfilter_init(void)
return -ENOMEM;
}
#endif
+ RCU_INIT_POINTER(nf_br_ops, &br_ops);
printk(KERN_NOTICE "Bridge firewalling registered\n");
return 0;
}
static void __exit br_netfilter_fini(void)
{
+ RCU_INIT_POINTER(nf_br_ops, NULL);
nf_unregister_hooks(br_nf_ops, ARRAY_SIZE(br_nf_ops));
#ifdef CONFIG_SYSCTL
unregister_net_sysctl_table(brnf_sysctl_header);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index f0a0438..b46fa0c 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -763,17 +763,17 @@ static inline int br_vlan_enabled(struct net_bridge *br)
}
#endif
+struct nf_br_ops {
+ int (*br_dev_xmit_hook)(struct sk_buff *skb);
+};
+extern const struct nf_br_ops __rcu *nf_br_ops;
+
/* br_netfilter.c */
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
-int br_nf_prerouting_finish_bridge(struct sk_buff *skb);
int br_nf_core_init(void);
void br_nf_core_fini(void);
void br_netfilter_rtable_init(struct net_bridge *);
#else
-static inline int br_nf_prerouting_finish_bridge(struct sk_buff *skb)
-{
- return 0;
-}
static inline int br_nf_core_init(void) { return 0; }
static inline void br_nf_core_fini(void) {}
#define br_netfilter_rtable_init(x)
--
1.7.10.4
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