On Wed, Apr 09, 2025 at 03:44:44PM +0800, Huajian Yang wrote: > The config NF_CONNTRACK_BRIDGE will change the way fragments are processed. > Bridge does not know that it is a fragmented packet and forwards it > directly, after NF_CONNTRACK_BRIDGE is enabled, function nf_br_ip_fragment > will check and fraglist this packet. > > Some network devices that would not able to ping large packet under bridge, > but large packet ping is successful if not enable NF_CONNTRACK_BRIDGE. > > In function nf_br_ip_fragment, checking the headroom before sending is > undoubted, but it is unreasonable to directly drop skb with insufficient > headroom. > > Using skb_copy_expand to expand the headroom of skb instead of dropping > it. > > Signed-off-by: Huajian Yang <huajianyang@xxxxxxxxxxxx> > --- > net/bridge/netfilter/nf_conntrack_bridge.c | 14 ++++++++++++-- > net/ipv6/netfilter.c | 14 ++++++++++++-- > 2 files changed, 24 insertions(+), 4 deletions(-) > > diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c > index 816bb0fde718..b8fb81a49377 100644 > --- a/net/bridge/netfilter/nf_conntrack_bridge.c > +++ b/net/bridge/netfilter/nf_conntrack_bridge.c ... > @@ -97,6 +97,16 @@ static int nf_br_ip_fragment(struct net *net, struct sock *sk, > > return err; > } > + > +expand_headroom: > + struct sk_buff *expand_skb; Please move this declaration to the top of the function. Flagged by W=1 builds with gcc 14.2.0 and clang 20.1.2. > + > + expand_skb = skb_copy_expand(skb, ll_rs, skb_tailroom(skb), GFP_ATOMIC); > + if (unlikely(!expand_skb)) > + goto blackhole; > + kfree_skb(skb); > + skb = expand_skb; > + > slow_path: > /* This is a linearized skbuff, the original geometry is lost for us. > * This may also be a clone skbuff, we could preserve the geometry for ...
