From ca1c8f3e782dc68a51aa2792771d9b4aac696ddd Mon Sep 17 00:00:00 2001 From: Florin Coras Date: Wed, 23 May 2018 21:01:30 -0700 Subject: tcp: loss recovery improvements/fixes - fix newreno cwnd computation - reset snd_una_max on entering recovery - accept acks beyond snd_nxt but less than snd_congestion when in recovery - avoid entering fast recovery multiple times when using sacks - avoid as much as possible sending small segments when doing fast retransmit - more event logging Change-Id: I19dd151d7704e39d4eae06de3a26f5e124875366 Signed-off-by: Florin Coras --- src/vnet/tcp/tcp_output.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) (limited to 'src/vnet/tcp/tcp_output.c') diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c index 27450654f71..a036287a51c 100644 --- a/src/vnet/tcp/tcp_output.c +++ b/src/vnet/tcp/tcp_output.c @@ -389,6 +389,7 @@ tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts, { case TCP_STATE_ESTABLISHED: case TCP_STATE_FIN_WAIT_1: + case TCP_STATE_CLOSED: return tcp_make_established_options (tc, opts); case TCP_STATE_SYN_RCVD: return tcp_make_synack_options (tc, opts); @@ -1337,8 +1338,9 @@ done: * Reset congestion control, switch cwnd to loss window and try again. */ static void -tcp_rtx_timeout_cc (tcp_connection_t * tc) +tcp_rxt_timeout_cc (tcp_connection_t * tc) { + TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 6); tc->prev_ssthresh = tc->ssthresh; tc->prev_cwnd = tc->cwnd; @@ -1383,6 +1385,8 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn) tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID; } + TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1); + if (tc->state >= TCP_STATE_ESTABLISHED) { /* Lost FIN, retransmit and return */ @@ -1414,13 +1418,11 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn) /* First retransmit timeout */ if (tc->rto_boff == 1) - tcp_rtx_timeout_cc (tc); + tcp_rxt_timeout_cc (tc); tc->snd_una_max = tc->snd_nxt = tc->snd_una; tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX); - TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1); - /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */ n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b); @@ -1627,7 +1629,7 @@ void tcp_fast_retransmit_sack (tcp_connection_t * tc) { vlib_main_t *vm = vlib_get_main (); - u32 n_written = 0, offset, max_bytes; + u32 n_written = 0, offset, max_bytes, n_segs = 0; vlib_buffer_t *b = 0; sack_scoreboard_hole_t *hole; sack_scoreboard_t *sb; @@ -1636,14 +1638,17 @@ tcp_fast_retransmit_sack (tcp_connection_t * tc) u8 snd_limited = 0, can_rescue = 0; ASSERT (tcp_in_fastrecovery (tc)); - TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0); old_snd_nxt = tc->snd_nxt; sb = &tc->sack_sb; - snd_space = tcp_available_snd_space (tc); + snd_space = tcp_available_cc_snd_space (tc); + if (snd_space < tc->snd_mss) + goto done; + + TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0); hole = scoreboard_get_hole (sb, sb->cur_rxt_hole); - while (hole && snd_space > 0) + while (hole && snd_space > 0 && n_segs++ < VLIB_FRAME_SIZE) { hole = scoreboard_next_rxt_hole (sb, hole, tcp_fastrecovery_sent_1_smss (tc), @@ -1717,7 +1722,7 @@ tcp_fast_retransmit_no_sack (tcp_connection_t * tc) /* Start resending from first un-acked segment */ old_snd_nxt = tc->snd_nxt; tc->snd_nxt = tc->snd_una; - snd_space = tcp_available_snd_space (tc); + snd_space = tcp_available_cc_snd_space (tc); while (snd_space > 0) { @@ -1743,8 +1748,7 @@ tcp_fast_retransmit_no_sack (tcp_connection_t * tc) void tcp_fast_retransmit (tcp_connection_t * tc) { - if (tcp_opts_sack_permitted (&tc->rcv_opts) - && scoreboard_first_hole (&tc->sack_sb)) + if (tcp_opts_sack_permitted (&tc->rcv_opts)) tcp_fast_retransmit_sack (tc); else tcp_fast_retransmit_no_sack (tc); -- cgit 1.2.3-korg