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authorFlorin Coras <fcoras@cisco.com>2017-03-30 02:54:28 -0700
committerDave Barach <openvpp@barachs.net>2017-04-02 14:02:30 +0000
commit3e350af5d3e9744a4529a28dd293b2d4601442f7 (patch)
treee4b489ddd509fc96382d49592cfc5bafc412a216 /src/vnet/tcp/tcp_output.c
parent799e26d5bdf6b74ab615644e0cd291de6e352989 (diff)
TCP cc/window management fixes and debugging
- added persist timer - update rcv_las whenever sending an ack - moved fifo size to its own cache line - improved session and builtin client debugging Change-Id: Ia649cf942cf0c061a713e8b67f0eb6974a6cd55b Signed-off-by: Florin Coras <fcoras@cisco.com> Signed-off-by: Dave Barach <dave@barachs.net>
Diffstat (limited to 'src/vnet/tcp/tcp_output.c')
-rw-r--r--src/vnet/tcp/tcp_output.c79
1 files changed, 66 insertions, 13 deletions
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index a671f728824..ea157bd76b7 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -155,8 +155,7 @@ tcp_update_rcv_wnd (tcp_connection_t * tc)
max_fifo = stream_session_fifo_size (&tc->connection);
ASSERT (tc->opt.mss < max_fifo);
-
- if (available_space < tc->opt.mss && available_space < max_fifo / 8)
+ if (available_space < tc->opt.mss && available_space < max_fifo >> 3)
available_space = 0;
/*
@@ -170,16 +169,21 @@ tcp_update_rcv_wnd (tcp_connection_t * tc)
/* Bad. Thou shalt not shrink */
if (available_space < observed_wnd)
{
- /* Does happen! */
wnd = observed_wnd;
+ TCP_EVT_DBG (TCP_EVT_RCV_WND_SHRUNK, tc, observed_wnd, available_space);
}
else
{
wnd = available_space;
}
- if (wnd && ((wnd << tc->rcv_wscale) >> tc->rcv_wscale != wnd))
- wnd += 1 << tc->rcv_wscale;
+ /* Make sure we have a multiple of rcv_wscale */
+ if (wnd && tc->rcv_wscale)
+ {
+ wnd &= ~(1 << tc->rcv_wscale);
+ if (wnd == 0)
+ wnd = 1 << tc->rcv_wscale;
+ }
tc->rcv_wnd = clib_min (wnd, TCP_WND_MAX << tc->rcv_wscale);
}
@@ -462,8 +466,9 @@ tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
tcp_reuse_buffer (vm, b);
tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
- vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc);
+ vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
+ tc->rcv_las = tc->rcv_nxt;
}
/**
@@ -908,6 +913,7 @@ tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
tc->snd_nxt += data_len;
+
/* TODO this is updated in output as well ... */
if (tc->snd_nxt > tc->snd_una_max)
tc->snd_una_max = tc->snd_nxt;
@@ -929,7 +935,6 @@ tcp_send_ack (tcp_connection_t * tc)
/* Fill in the ACK */
tcp_make_ack (tc, b);
-
tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
}
@@ -942,7 +947,6 @@ tcp_timer_delack_handler (u32 index)
tc = tcp_connection_get (index, thread_index);
tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID;
-// tc->flags &= ~TCP_CONN_DELACK;
tcp_send_ack (tc);
}
@@ -995,7 +999,7 @@ done:
* Reset congestion control, switch cwnd to loss window and try again.
*/
static void
-tcp_rtx_timeout_cc_recover (tcp_connection_t * tc)
+tcp_rtx_timeout_cc (tcp_connection_t * tc)
{
/* Cleanly recover cc (also clears up fast retransmit) */
if (tcp_in_fastrecovery (tc))
@@ -1008,6 +1012,7 @@ tcp_rtx_timeout_cc_recover (tcp_connection_t * tc)
}
/* Start again from the beginning */
+ tcp_recovery_on (tc);
tc->cwnd = tcp_loss_wnd (tc);
tc->snd_congestion = tc->snd_una_max;
}
@@ -1048,7 +1053,7 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
{
/* First retransmit timeout */
if (tc->rto_boff == 1)
- tcp_rtx_timeout_cc_recover (tc);
+ tcp_rtx_timeout_cc (tc);
/* Exponential backoff */
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
@@ -1114,6 +1119,8 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
{
ASSERT (tc->state == TCP_STATE_SYN_SENT);
+ TCP_EVT_DBG (TCP_EVT_SYN_RTX, tc);
+
/* This goes straight to ipx_lookup */
tcp_push_ip_hdr (tm, tc, b);
tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4);
@@ -1137,6 +1144,55 @@ tcp_timer_retransmit_syn_handler (u32 index)
}
/**
+ * Got 0 snd_wnd from peer, try to do something about it.
+ *
+ */
+void
+tcp_timer_persist_handler (u32 index)
+{
+ tcp_main_t *tm = vnet_get_tcp_main ();
+ vlib_main_t *vm = vlib_get_main ();
+ u32 thread_index = os_get_cpu_number ();
+ tcp_connection_t *tc;
+ vlib_buffer_t *b;
+ u32 bi, n_bytes;
+
+ tc = tcp_connection_get (index, thread_index);
+
+ /* Make sure timer handle is set to invalid */
+ tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID;
+
+ /* Problem already solved or worse */
+ if (tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc))
+ return;
+
+ /* Increment RTO backoff */
+ tc->rto_boff += 1;
+ tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
+
+ /* Try to force the first unsent segment */
+ tcp_get_free_buffer_index (tm, &bi);
+ b = vlib_get_buffer (vm, bi);
+ n_bytes = stream_session_peek_bytes (&tc->connection,
+ vlib_buffer_get_current (b),
+ tc->snd_una_max - tc->snd_una,
+ tc->snd_mss);
+ /* Nothing to send */
+ if (n_bytes == 0)
+ {
+ tcp_return_buffer (tm);
+ return;
+ }
+
+ b->current_length = n_bytes;
+ tcp_push_hdr_i (tc, b, tc->state);
+ tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4);
+
+ /* Re-enable persist timer */
+ tcp_persist_timer_set (tc);
+}
+
+/**
* Retransmit first unacked segment
*/
void
@@ -1329,9 +1385,6 @@ tcp46_output_inline (vlib_main_t * vm,
}
}
- /* Retransmitted SYNs do reach this but it should be harmless */
- tc0->rcv_las = tc0->rcv_nxt;
-
/* Stop DELACK timer and fix flags */
tc0->flags &= ~(TCP_CONN_SNDACK);
if (tcp_timer_is_active (tc0, TCP_TIMER_DELACK))