From: zheng li <james.z...@ericsson.com> There is an inconsitent conditional judgement in __ip_append_data and ip_finish_output functions, the variable length in __ip_append_data just include the length of applicatoin's payload and udp header, don't include the length of ip header, but in ip_finish_output use (skb->len > ip_skb_dst_mtu(skb)) as judgement, and skb->len include the length of ip header.
That cuase some particular applicatoin's udp payload whose length is between (MTU - IP Header) and MTU were framented by ip_fragment even though the rst->dev support UFO features. Add the length of ip header to length in __ip_append_data to keep consistent conditional judgement as ip_finish_output for ip fragment. Signed-off-by: Zheng Li <james.z...@ericsson.com> --- net/ipv4/ip_output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 877bdb0..12a0149 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -936,7 +936,7 @@ static int __ip_append_data(struct sock *sk, csummode = CHECKSUM_PARTIAL; cork->length += length; - if (((length > mtu) || (skb && skb_is_gso(skb))) && + if ((((length + fragheaderlen) > mtu) || (skb && skb_is_gso(skb))) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len && (sk->sk_type == SOCK_DGRAM) && !sk->sk_no_check_tx) { -- 2.7.4