Messages in this thread Patch in this message | | | Date | Wed, 18 Apr 2012 15:57:23 +0800 | From | "Peter Huang(Peng)" <> | Subject | Re: [PATCH] set fake_rtable's dst to NULL to avoid kernel Oops. |
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On 2012/4/18 0:48, Eric Dumazet wrote: > On Tue, 2012-04-17 at 08:52 -0700, Stephen Hemminger wrote: > >> This check seems like a disaster waiting to happen when the next >> change to DST table happens. > > Please Peter Document this, adding a new DST_FAKE_RTABLE flag > > #define DST_FAKE_RTABLE DST_NOPEER > > or just use a bit, we have plenty of them available. >
Add DST_FAKE_RTABLE to dst_entry, this is the new patch. Is this ok?
Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Peter Huang <peter.huangpeng@huawei.com> --- include/linux/netfilter_bridge.h | 8 ++++++++ include/net/dst.h | 1 + net/bridge/br_forward.c | 1 + net/bridge/br_netfilter.c | 8 ++------ 4 files changed, 12 insertions(+), 6 deletions(-) diff --git a/include/linux/netfilter_bridge.h b/include/linux/netfilter_bridge.h index 0ddd161..eb09e3b 100644 --- a/include/linux/netfilter_bridge.h +++ b/include/linux/netfilter_bridge.h @@ -104,9 +104,17 @@ struct bridge_skb_cb { } daddr; };
+static inline void br_drop_fake_rtable(struct sk_buff *skb) { + struct dst_entry *dst = skb_dst(skb); + /* abuse fact that only fake_rtable has DST_FAKE_RTABLE set */ + if (dst && (dst->flags & DST_FAKE_RTABLE)) + skb_dst_drop(skb); +} + #else #define nf_bridge_maybe_copy_header(skb) (0) #define nf_bridge_pad(skb) (0) +#define br_drop_fake_rtable(skb) (0) #endif /* CONFIG_BRIDGE_NETFILTER */
#endif /* __KERNEL__ */ diff --git a/include/net/dst.h b/include/net/dst.h index 59c5d18..b094030 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -55,6 +55,7 @@ struct dst_entry { #define DST_NOCACHE 0x0010 #define DST_NOCOUNT 0x0020 #define DST_NOPEER 0x0040 +#define DST_FAKE_RTABLE 0x0080
short error; short obsolete; diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c index 61f6534..a2098e3 100644 --- a/net/bridge/br_forward.c +++ b/net/bridge/br_forward.c @@ -47,6 +47,7 @@ int br_dev_queue_push_xmit(struct sk_buff *skb) kfree_skb(skb); } else { skb_push(skb, ETH_HLEN); + br_drop_fake_rtable(skb); dev_queue_xmit(skb); }
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c index dec4f38..d7f49b6 100644 --- a/net/bridge/br_netfilter.c +++ b/net/bridge/br_netfilter.c @@ -156,7 +156,7 @@ void br_netfilter_rtable_init(struct net_bridge *br) rt->dst.dev = br->dev; rt->dst.path = &rt->dst; dst_init_metrics(&rt->dst, br_dst_default_metrics, true); - rt->dst.flags = DST_NOXFRM | DST_NOPEER; + rt->dst.flags = DST_NOXFRM | DST_NOPEER | DST_FAKE_RTABLE; rt->dst.ops = &fake_dst_ops; }
@@ -694,11 +694,7 @@ static unsigned int br_nf_local_in(unsigned int hook, struct sk_buff *skb, const struct net_device *out, int (*okfn)(struct sk_buff *)) { - struct rtable *rt = skb_rtable(skb); - - if (rt && rt == bridge_parent_rtable(in)) - skb_dst_drop(skb); - + br_drop_fake_rtable(skb); return NF_ACCEPT; }
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