From: Lina Wang <lina.w...@mediatek.com>
In tunnel mode, when inner interface is ipv4,outer interface is ipv6, flags
of tunnel mode's xfrm state is af-unspec, if a larger packet who is bigger
than mtu goes through tunnel interface, it enters ip6_fragment, goes to
fail_toobig, and ICMPV6(ICMPV6_PKT_TOOBIG) will be sent. It is unnecessary
to do so. Ip6_fragment will fragment such packet with outer interface's mtu
minus tunnelled esp header,it wonot be too big.
The same things happen, when a larger fragmented packet whose frag_max_size
is larger than mtu.
When a larger fragmented packet is forwarded, it also meets the same
scenary.
This patch has handled three above scenaries, if it is tunnel mode,just
ignore skb_len or frag_max_size, keep going.
Signed-off-by: Lina Wang <lina.w...@mediatek.com>
---
net/ipv6/ip6_output.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index c78e67d7747f..0e1e6fcd7a5d 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -402,12 +402,14 @@ static inline int ip6_forward_finish(struct net *net,
struct sock *sk,
static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
{
+ struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
if (skb->len <= mtu)
return false;
/* ipv6 conntrack defrag sets max_frag_size + ignore_df */
if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
- return true;
+ if (rt && !(rt->dst.flags & DST_XFRM_TUNNEL))
+ return true;
if (skb->ignore_df)
return false;
@@ -787,16 +789,19 @@ int ip6_fragment(struct net *net, struct sock *sk, struct
sk_buff *skb,
* or if the skb it not generated by a local socket.
*/
if (unlikely(!skb->ignore_df && skb->len > mtu))
- goto fail_toobig;
-
- if (IP6CB(skb)->frag_max_size) {
- if (IP6CB(skb)->frag_max_size > mtu)
+ if (rt && (rt->dst.flags & DST_XFRM_TUNNEL))
goto fail_toobig;
- /* don't send fragments larger than what we received */
- mtu = IP6CB(skb)->frag_max_size;
- if (mtu < IPV6_MIN_MTU)
- mtu = IPV6_MIN_MTU;
+ if (IP6CB(skb)->frag_max_size) {
+ if (IP6CB(skb)->frag_max_size > mtu) {
+ if (rt && !(rt->dst.flags & DST_XFRM_TUNNEL))
+ goto fail_toobig;
+ } else {
+ /* don't send fragments larger than what we received */
+ mtu = IP6CB(skb)->frag_max_size;
+ if (mtu < IPV6_MIN_MTU)
+ mtu = IPV6_MIN_MTU;
+ }
}
if (np && np->frag_size < mtu) {
--
2.18.0
