[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: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index b018e31..5dd6dd7 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -461,9 +461,7 @@
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 @@
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;