diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_input.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index da777df0a0ba..ef921ecba415 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4348,6 +4348,12 @@ static void tcp_sack_compress_send_ack(struct sock *sk) tcp_send_ack(sk); } +/* Reasonable amount of sack blocks included in TCP SACK option + * The max is 4, but this becomes 3 if TCP timestamps are there. + * Given that SACK packets might be lost, be conservative and use 2. + */ +#define TCP_SACK_BLOCKS_EXPECTED 2 + static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq) { struct tcp_sock *tp = tcp_sk(sk); @@ -4360,6 +4366,8 @@ static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq) for (this_sack = 0; this_sack < cur_sacks; this_sack++, sp++) { if (tcp_sack_extend(sp, seq, end_seq)) { + if (this_sack >= TCP_SACK_BLOCKS_EXPECTED) + tcp_sack_compress_send_ack(sk); /* Rotate this_sack to the first one. */ for (; this_sack > 0; this_sack--, sp--) swap(*sp, *(sp - 1)); @@ -4369,6 +4377,9 @@ static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq) } } + if (this_sack >= TCP_SACK_BLOCKS_EXPECTED) + tcp_sack_compress_send_ack(sk); + /* Could not find an adjacent existing SACK, build a new one, * put it at the front, and shift everyone else down. We * always know there is at least one SACK present already here. @@ -4376,7 +4387,6 @@ static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq) * If the sack array is full, forget about the last one. */ if (this_sack >= TCP_NUM_SACKS) { - tcp_sack_compress_send_ack(sk); this_sack--; tp->rx_opt.num_sacks--; sp--; |