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Commit e14c3caf authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

[TCP]: Handle SACK'd packets properly in tcp_fragment(). 



The problem is that we're now calling tcp_fragment() in a context
where the packets might be marked as SACKED_ACKED or SACKED_RETRANS.
This was not possible before as you never retransmitted packets that
are so marked.

Because of this, we need to adjust sacked_out and retrans_out in
tcp_fragment().  This is exactly what the following patch does.

We also need to preserve the SACKED_ACKED/SACKED_RETRANS marking
if they exist.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3c3f8f25

net/ipv4/tcp_output.c

+7 −3
Original line number Diff line number Diff line
@@ -461,9 +461,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss 
	flags = TCP_SKB_CB(skb)->flags;

	TCP_SKB_CB(skb)->flags = flags & ~(TCPCB_FLAG_FIN|TCPCB_FLAG_PSH);

	TCP_SKB_CB(buff)->flags = flags;

	TCP_SKB_CB(buff)->sacked =

		(TCP_SKB_CB(skb)->sacked &

		 (TCPCB_LOST | TCPCB_EVER_RETRANS | TCPCB_AT_TAIL));

	TCP_SKB_CB(buff)->sacked = TCP_SKB_CB(skb)->sacked;

	TCP_SKB_CB(skb)->sacked &= ~TCPCB_AT_TAIL;



	if (!skb_shinfo(skb)->nr_frags && skb->ip_summed != CHECKSUM_HW) {
@@ -501,6 +499,12 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss 
			tcp_skb_pcount(buff);



		tp->packets_out -= diff;



		if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)

			tp->sacked_out -= diff;

		if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)

			tp->retrans_out -= diff;



		if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST) {

			tp->lost_out -= diff;

			tp->left_out -= diff;