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ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output

Message ID 1481252918-3514-1-git-send-email-lizheng043@gmail.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Zheng Li Dec. 9, 2016, 3:08 a.m. UTC 
From: zheng li <james.z.li@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 feature.

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.li@ericsson.com>
---
 net/ipv4/ip_output.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Sergei Shtylyov Dec. 9, 2016, 12:03 p.m. UTC | #1 
Hello!

On 12/9/2016 6:08 AM, Zheng Li wrote:

> From: zheng li <james.z.li@ericsson.com>
>
> There is an inconsitent conditional judgement in __ip_append_data and

    Inconsistent.

> 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

    Application.

> 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

    Causes, application.

> between (MTU - IP Header) and MTU were framented by ip_fragment even

    Fragmented.

> though the rst->dev support UFO feature.
>
> 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.li@ericsson.com>
[...]

MBR, Sergei
diff mbox

Patch

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) {