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authorFlorin Coras <fcoras@cisco.com>2019-07-23 23:54:47 -0700
committerDave Wallace <dwallacelf@gmail.com>2019-07-26 14:39:30 +0000
commit26dd6de91b4d36ac04154c7eb6339684db6684a0 (patch)
tree202ff4daf1747dcf97de0efcae7af74be6f6bc64 /src/vnet/tcp
parent038e1dfbdfd0bd785852c364011da0a1d828093e (diff)
session tcp: handle rxt and acks as custom events
Type: feature Control ack generation and retransmissions with session layer scheduler. Change-Id: Iacdf9f84ab81f44851980aa45a83e75f29be2b7b Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src/vnet/tcp')
-rw-r--r--src/vnet/tcp/tcp.c11
-rw-r--r--src/vnet/tcp/tcp.h24
-rwxr-xr-xsrc/vnet/tcp/tcp_input.c109
-rw-r--r--src/vnet/tcp/tcp_output.c167
4 files changed, 138 insertions, 173 deletions
diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index 928d1bac257..5a215b658a0 100644
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -1196,8 +1196,6 @@ tcp_update_time (f64 now, u8 thread_index)
tcp_set_time_now (wrk);
tw_timer_expire_timers_16t_2w_512sl (&wrk->timer_wheel, now);
- tcp_do_fastretransmits (wrk);
- tcp_send_acks (wrk);
tcp_flush_frames_to_output (wrk);
}
@@ -1228,6 +1226,7 @@ const static transport_proto_vft_t tcp_proto = {
.update_time = tcp_update_time,
.tx_fifo_offset = tcp_session_tx_fifo_offset,
.flush_data = tcp_session_flush_data,
+ .custom_tx = tcp_session_custom_tx,
.format_connection = format_tcp_session,
.format_listener = format_tcp_listener_session,
.format_half_open = format_tcp_half_open_session,
@@ -1476,17 +1475,9 @@ tcp_main_enable (vlib_main_t * vm)
for (thread = 0; thread < num_threads; thread++)
{
- vec_validate (tm->wrk_ctx[thread].pending_fast_rxt, 255);
- vec_validate (tm->wrk_ctx[thread].ongoing_fast_rxt, 255);
- vec_validate (tm->wrk_ctx[thread].postponed_fast_rxt, 255);
vec_validate (tm->wrk_ctx[thread].pending_deq_acked, 255);
- vec_validate (tm->wrk_ctx[thread].pending_acks, 255);
vec_validate (tm->wrk_ctx[thread].pending_disconnects, 255);
- vec_reset_length (tm->wrk_ctx[thread].pending_fast_rxt);
- vec_reset_length (tm->wrk_ctx[thread].ongoing_fast_rxt);
- vec_reset_length (tm->wrk_ctx[thread].postponed_fast_rxt);
vec_reset_length (tm->wrk_ctx[thread].pending_deq_acked);
- vec_reset_length (tm->wrk_ctx[thread].pending_acks);
vec_reset_length (tm->wrk_ctx[thread].pending_disconnects);
tm->wrk_ctx[thread].vm = vlib_mains[thread];
diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index 7ccc06aea9c..8f2665d2a6a 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -464,21 +464,9 @@ typedef struct tcp_worker_ctx_
/** tx frames for ip 4/6 lookup nodes */
vlib_frame_t *ip_lookup_tx_frames[2];
- /** vector of connections needing fast rxt */
- u32 *pending_fast_rxt;
-
- /** vector of connections now doing fast rxt */
- u32 *ongoing_fast_rxt;
-
- /** vector of connections that will do fast rxt */
- u32 *postponed_fast_rxt;
-
/** vector of pending ack dequeues */
u32 *pending_deq_acked;
- /** vector of pending acks */
- u32 *pending_acks;
-
/** vector of pending disconnect notifications */
u32 *pending_disconnects;
@@ -700,15 +688,12 @@ void tcp_update_burst_snd_vars (tcp_connection_t * tc);
void tcp_update_rto (tcp_connection_t * tc);
void tcp_flush_frame_to_output (tcp_worker_ctx_t * wrk, u8 is_ip4);
void tcp_flush_frames_to_output (tcp_worker_ctx_t * wrk);
-void tcp_program_fastretransmit (tcp_worker_ctx_t * wrk,
- tcp_connection_t * tc);
-void tcp_do_fastretransmits (tcp_worker_ctx_t * wrk);
-
-void tcp_program_ack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc);
-void tcp_program_dupack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc);
-void tcp_send_acks (tcp_worker_ctx_t * wrk);
void tcp_send_window_update_ack (tcp_connection_t * tc);
+void tcp_program_ack (tcp_connection_t * tc);
+void tcp_program_dupack (tcp_connection_t * tc);
+void tcp_program_fastretransmit (tcp_connection_t * tc);
+
/*
* Rate estimation
*/
@@ -961,6 +946,7 @@ tcp_set_time_now (tcp_worker_ctx_t * wrk)
u32 tcp_session_push_header (transport_connection_t * tconn,
vlib_buffer_t * b);
+int tcp_session_custom_tx (void *conn, u32 max_burst_size);
void tcp_connection_timers_init (tcp_connection_t * tc);
void tcp_connection_timers_reset (tcp_connection_t * tc);
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 5f3764893c9..4695fbb1161 100755
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -317,7 +317,7 @@ tcp_segment_validate (tcp_worker_ctx_t * wrk, tcp_connection_t * tc0,
* SEG.TSval */
else if (!tcp_rst (th0))
{
- tcp_program_ack (wrk, tc0);
+ tcp_program_ack (tc0);
TCP_EVT_DBG (TCP_EVT_DUPACK_SENT, tc0, vnet_buffer (b0)->tcp);
goto error;
}
@@ -340,7 +340,7 @@ tcp_segment_validate (tcp_worker_ctx_t * wrk, tcp_connection_t * tc0,
}
else
{
- tcp_program_ack (wrk, tc0);
+ tcp_program_ack (tc0);
TCP_EVT_DBG (TCP_EVT_SYNACK_RCVD, tc0);
*error0 = TCP_ERROR_SYN_ACKS_RCVD;
}
@@ -368,7 +368,7 @@ tcp_segment_validate (tcp_worker_ctx_t * wrk, tcp_connection_t * tc0,
/* If not RST, send dup ack */
if (!tcp_rst (th0))
{
- tcp_program_dupack (wrk, tc0);
+ tcp_program_dupack (tc0);
TCP_EVT_DBG (TCP_EVT_DUPACK_SENT, tc0, vnet_buffer (b0)->tcp);
}
goto error;
@@ -391,7 +391,7 @@ tcp_segment_validate (tcp_worker_ctx_t * wrk, tcp_connection_t * tc0,
if (PREDICT_FALSE (tcp_syn (th0)))
{
/* As per RFC5961 send challenge ack instead of reset */
- tcp_program_ack (wrk, tc0);
+ tcp_program_ack (tc0);
*error0 = TCP_ERROR_SPURIOUS_SYN;
goto error;
}
@@ -1199,6 +1199,7 @@ tcp_cc_fastrecovery_clear (tcp_connection_t * tc)
tcp_fastrecovery_off (tc);
tcp_fastrecovery_first_off (tc);
+ tc->flags &= ~TCP_CONN_FRXT_PENDING;
TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3);
}
@@ -1305,81 +1306,6 @@ tcp_should_fastrecover (tcp_connection_t * tc)
|| tcp_should_fastrecover_sack (tc));
}
-#ifndef CLIB_MARCH_VARIANT
-void
-tcp_program_fastretransmit (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
-{
- if (!(tc->flags & TCP_CONN_FRXT_PENDING))
- {
- vec_add1 (wrk->pending_fast_rxt, tc->c_c_index);
- tc->flags |= TCP_CONN_FRXT_PENDING;
- }
-}
-
-void
-tcp_do_fastretransmits (tcp_worker_ctx_t * wrk)
-{
- u32 *ongoing_fast_rxt, burst_bytes, sent_bytes, thread_index;
- u32 max_burst_size, burst_size, n_segs = 0, n_segs_now;
- tcp_connection_t *tc;
- u64 last_cpu_time;
- int i;
-
- if (vec_len (wrk->pending_fast_rxt) == 0
- && vec_len (wrk->postponed_fast_rxt) == 0)
- return;
-
- thread_index = wrk->vm->thread_index;
- last_cpu_time = wrk->vm->clib_time.last_cpu_time;
- ongoing_fast_rxt = wrk->ongoing_fast_rxt;
- vec_append (ongoing_fast_rxt, wrk->postponed_fast_rxt);
- vec_append (ongoing_fast_rxt, wrk->pending_fast_rxt);
-
- _vec_len (wrk->postponed_fast_rxt) = 0;
- _vec_len (wrk->pending_fast_rxt) = 0;
-
- max_burst_size = VLIB_FRAME_SIZE / vec_len (ongoing_fast_rxt);
- max_burst_size = clib_max (max_burst_size, 1);
-
- for (i = 0; i < vec_len (ongoing_fast_rxt); i++)
- {
- tc = tcp_connection_get (ongoing_fast_rxt[i], thread_index);
- if (!tc)
- continue;
- if (!tcp_in_fastrecovery (tc))
- {
- tc->flags &= ~TCP_CONN_FRXT_PENDING;
- continue;
- }
-
- if (n_segs >= VLIB_FRAME_SIZE)
- {
- vec_add1 (wrk->postponed_fast_rxt, ongoing_fast_rxt[i]);
- continue;
- }
-
- tc->flags &= ~TCP_CONN_FRXT_PENDING;
- burst_size = clib_min (max_burst_size, VLIB_FRAME_SIZE - n_segs);
- burst_bytes = transport_connection_tx_pacer_burst (&tc->connection,
- last_cpu_time);
- burst_size = clib_min (burst_size, burst_bytes / tc->snd_mss);
- if (!burst_size)
- {
- tcp_program_fastretransmit (wrk, tc);
- continue;
- }
-
- n_segs_now = tcp_fast_retransmit (wrk, tc, burst_size);
- sent_bytes = clib_min (n_segs_now * tc->snd_mss, burst_bytes);
- transport_connection_tx_pacer_update_bytes (&tc->connection,
- sent_bytes);
- n_segs += n_segs_now;
- }
- _vec_len (ongoing_fast_rxt) = 0;
- wrk->ongoing_fast_rxt = ongoing_fast_rxt;
-}
-#endif /* CLIB_MARCH_VARIANT */
-
/**
* One function to rule them all ... and in the darkness bind them
*/
@@ -1393,7 +1319,7 @@ tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
{
if (tc->bytes_acked)
goto partial_ack;
- tcp_program_fastretransmit (tcp_get_worker (tc->c_thread_index), tc);
+ tcp_program_fastretransmit (tc);
return;
}
/*
@@ -1449,8 +1375,7 @@ tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
pacer_wnd = clib_max (0.1 * tc->cwnd, 2 * tc->snd_mss);
tcp_connection_tx_pacer_reset (tc, pacer_wnd,
0 /* start bucket */ );
- tcp_program_fastretransmit (tcp_get_worker (tc->c_thread_index),
- tc);
+ tcp_program_fastretransmit (tc);
return;
}
else if (!tc->bytes_acked
@@ -1571,7 +1496,7 @@ partial_ack:
/*
* Since this was a partial ack, try to retransmit some more data
*/
- tcp_program_fastretransmit (tcp_get_worker (tc->c_thread_index), tc);
+ tcp_program_fastretransmit (tc);
}
/**
@@ -1712,7 +1637,7 @@ tcp_rcv_fin (tcp_worker_ctx_t * wrk, tcp_connection_t * tc, vlib_buffer_t * b,
/* Account for the FIN and send ack */
tc->rcv_nxt += 1;
- tcp_program_ack (wrk, tc);
+ tcp_program_ack (tc);
/* Enter CLOSE-WAIT and notify session. To avoid lingering
* in CLOSE-WAIT, set timer (reuse WAITCLOSE). */
tcp_connection_set_state (tc, TCP_STATE_CLOSE_WAIT);
@@ -1976,7 +1901,7 @@ tcp_segment_rcv (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
* retransmissions since we may not have any data to send */
if (seq_leq (vnet_buffer (b)->tcp.seq_end, tc->rcv_nxt))
{
- tcp_program_ack (wrk, tc);
+ tcp_program_ack (tc);
error = TCP_ERROR_SEGMENT_OLD;
goto done;
}
@@ -1996,7 +1921,7 @@ tcp_segment_rcv (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
/* RFC2581: Enqueue and send DUPACK for fast retransmit */
error = tcp_session_enqueue_ooo (tc, b, n_data_bytes);
- tcp_program_dupack (wrk, tc);
+ tcp_program_dupack (tc);
TCP_EVT_DBG (TCP_EVT_DUPACK_SENT, tc, vnet_buffer (b)->tcp);
goto done;
}
@@ -2013,7 +1938,7 @@ in_order:
goto done;
}
- tcp_program_ack (wrk, tc);
+ tcp_program_ack (tc);
done:
return error;
@@ -2591,7 +2516,7 @@ tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
}
else
{
- tcp_program_ack (wrk, new_tc0);
+ tcp_program_ack (new_tc0);
}
drop:
@@ -2921,7 +2846,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
if (!is_fin0)
goto drop;
- tcp_program_ack (wrk, tc0);
+ tcp_program_ack (tc0);
tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_TIMEWAIT_TIME);
goto drop;
@@ -2961,7 +2886,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
case TCP_STATE_ESTABLISHED:
/* Account for the FIN and send ack */
tc0->rcv_nxt += 1;
- tcp_program_ack (wrk, tc0);
+ tcp_program_ack (tc0);
tcp_connection_set_state (tc0, TCP_STATE_CLOSE_WAIT);
tcp_program_disconnect (wrk, tc0);
tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_CLOSEWAIT_TIME);
@@ -2995,7 +2920,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
else
{
tcp_connection_set_state (tc0, TCP_STATE_CLOSING);
- tcp_program_ack (wrk, tc0);
+ tcp_program_ack (tc0);
/* Wait for ACK for our FIN but not forever */
tcp_timer_update (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME);
}
@@ -3006,7 +2931,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
tcp_connection_set_state (tc0, TCP_STATE_TIME_WAIT);
tcp_connection_timers_reset (tc0);
tcp_timer_set (tc0, TCP_TIMER_WAITCLOSE, TCP_TIMEWAIT_TIME);
- tcp_program_ack (wrk, tc0);
+ tcp_program_ack (tc0);
session_transport_closed_notify (&tc0->connection);
break;
case TCP_STATE_TIME_WAIT:
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 7b0303f3033..79cc95e9f0b 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -1188,21 +1188,21 @@ tcp_send_ack (tcp_connection_t * tc)
}
void
-tcp_program_ack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
+tcp_program_ack (tcp_connection_t * tc)
{
if (!(tc->flags & TCP_CONN_SNDACK))
{
- vec_add1 (wrk->pending_acks, tc->c_c_index);
+ session_add_self_custom_tx_evt (&tc->connection, 1);
tc->flags |= TCP_CONN_SNDACK;
}
}
void
-tcp_program_dupack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
+tcp_program_dupack (tcp_connection_t * tc)
{
if (!(tc->flags & TCP_CONN_SNDACK))
{
- vec_add1 (wrk->pending_acks, tc->c_c_index);
+ session_add_self_custom_tx_evt (&tc->connection, 1);
tc->flags |= TCP_CONN_SNDACK;
}
if (tc->pending_dupacks < 255)
@@ -1210,51 +1210,13 @@ tcp_program_dupack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
}
void
-tcp_send_acks (tcp_worker_ctx_t * wrk)
+tcp_program_fastretransmit (tcp_connection_t * tc)
{
- u32 thread_index, *pending_acks;
- tcp_connection_t *tc;
- int i, j, n_acks;
-
- if (!vec_len (wrk->pending_acks))
- return;
-
- thread_index = wrk->vm->thread_index;
- pending_acks = wrk->pending_acks;
- for (i = 0; i < vec_len (pending_acks); i++)
+ if (!(tc->flags & TCP_CONN_FRXT_PENDING))
{
- tc = tcp_connection_get (pending_acks[i], thread_index);
- tc->flags &= ~TCP_CONN_SNDACK;
- if (!tc->pending_dupacks)
- {
- tcp_send_ack (tc);
- continue;
- }
-
- /* If we're supposed to send dupacks but have no ooo data
- * send only one ack */
- if (!vec_len (tc->snd_sacks))
- {
- tcp_send_ack (tc);
- continue;
- }
-
- /* Start with first sack block */
- tc->snd_sack_pos = 0;
-
- /* Generate enough dupacks to cover all sack blocks. Do not generate
- * more sacks than the number of packets received. But do generate at
- * least 3, i.e., the number needed to signal congestion, if needed. */
- n_acks = vec_len (tc->snd_sacks) / TCP_OPTS_MAX_SACK_BLOCKS;
- n_acks = clib_min (n_acks, tc->pending_dupacks);
- n_acks = clib_max (n_acks, clib_min (tc->pending_dupacks, 3));
- for (j = 0; j < n_acks; j++)
- tcp_send_ack (tc);
-
- tc->pending_dupacks = 0;
- tc->snd_sack_pos = 0;
+ session_add_self_custom_tx_evt (&tc->connection, 0);
+ tc->flags |= TCP_CONN_FRXT_PENDING;
}
- _vec_len (wrk->pending_acks) = 0;
}
/**
@@ -1281,7 +1243,6 @@ tcp_timer_delack_handler (u32 index)
void
tcp_send_window_update_ack (tcp_connection_t * tc)
{
- tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
u32 win;
if (tcp_zero_rwnd_sent (tc))
@@ -1290,7 +1251,7 @@ tcp_send_window_update_ack (tcp_connection_t * tc)
if (win > 0)
{
tcp_zero_rwnd_sent_off (tc);
- tcp_program_ack (wrk, tc);
+ tcp_program_ack (tc);
}
}
}
@@ -1853,7 +1814,7 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
snd_space = tcp_available_cc_snd_space (tc);
if (snd_space < tc->snd_mss)
{
- tcp_program_fastretransmit (wrk, tc);
+ tcp_program_fastretransmit (tc);
return 0;
}
@@ -1877,7 +1838,7 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
snd_space / tc->snd_mss);
n_segs_now = tcp_fast_retransmit_unsent (wrk, tc, burst_size);
if (max_deq > n_segs_now * tc->snd_mss)
- tcp_program_fastretransmit (wrk, tc);
+ tcp_program_fastretransmit (tc);
n_segs += n_segs_now;
goto done;
}
@@ -1929,7 +1890,7 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
}
if (hole)
- tcp_program_fastretransmit (wrk, tc);
+ tcp_program_fastretransmit (tc);
done:
return n_segs;
@@ -1990,7 +1951,7 @@ send_unsent:
burst_size = clib_min (burst_size - n_segs, snd_space / tc->snd_mss);
n_segs_now = tcp_fast_retransmit_unsent (wrk, tc, burst_size);
if (max_deq > n_segs_now * tc->snd_mss)
- tcp_program_fastretransmit (wrk, tc);
+ tcp_program_fastretransmit (tc);
n_segs += n_segs_now;
}
@@ -2011,6 +1972,108 @@ tcp_fast_retransmit (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
else
return tcp_fast_retransmit_no_sack (wrk, tc, burst_size);
}
+
+static int
+tcp_send_acks (tcp_connection_t * tc, u32 max_burst_size)
+{
+ int j, n_acks;
+
+ if (!tc->pending_dupacks)
+ {
+ tcp_send_ack (tc);
+ return 1;
+ }
+
+ /* If we're supposed to send dupacks but have no ooo data
+ * send only one ack */
+ if (!vec_len (tc->snd_sacks))
+ {
+ tcp_send_ack (tc);
+ return 1;
+ }
+
+ /* Start with first sack block */
+ tc->snd_sack_pos = 0;
+
+ /* Generate enough dupacks to cover all sack blocks. Do not generate
+ * more sacks than the number of packets received. But do generate at
+ * least 3, i.e., the number needed to signal congestion, if needed. */
+ n_acks = vec_len (tc->snd_sacks) / TCP_OPTS_MAX_SACK_BLOCKS;
+ n_acks = clib_min (n_acks, tc->pending_dupacks);
+ n_acks = clib_max (n_acks, clib_min (tc->pending_dupacks, 3));
+ for (j = 0; j < clib_min (n_acks, max_burst_size); j++)
+ tcp_send_ack (tc);
+
+ if (n_acks < max_burst_size)
+ {
+ tc->pending_dupacks = 0;
+ tc->snd_sack_pos = 0;
+ return n_acks;
+ }
+ else
+ {
+ TCP_DBG ("constrained by burst size");
+ tc->pending_dupacks = n_acks - max_burst_size;
+ tcp_program_dupack (tc);
+ return max_burst_size;
+ }
+}
+
+static int
+tcp_do_fastretransmit (tcp_connection_t * tc, u32 max_burst_size)
+{
+ u32 n_segs = 0, burst_size, sent_bytes, burst_bytes;
+ tcp_worker_ctx_t *wrk;
+
+ wrk = tcp_get_worker (tc->c_thread_index);
+ burst_bytes = transport_connection_tx_pacer_burst (&tc->connection,
+ wrk->vm->
+ clib_time.last_cpu_time);
+ burst_size = clib_min (max_burst_size, burst_bytes / tc->snd_mss);
+ if (!burst_size)
+ {
+ tcp_program_fastretransmit (tc);
+ return 0;
+ }
+
+ n_segs = tcp_fast_retransmit (wrk, tc, burst_size);
+ sent_bytes = clib_min (n_segs * tc->snd_mss, burst_bytes);
+ transport_connection_tx_pacer_update_bytes (&tc->connection, sent_bytes);
+ return n_segs;
+}
+
+int
+tcp_session_custom_tx (void *conn, u32 max_burst_size)
+{
+ tcp_connection_t *tc = (tcp_connection_t *) conn;
+ u32 n_segs = 0;
+
+ if (tcp_in_fastrecovery (tc) && (tc->flags & TCP_CONN_FRXT_PENDING))
+ {
+ tc->flags &= ~TCP_CONN_FRXT_PENDING;
+ n_segs = tcp_do_fastretransmit (tc, max_burst_size);
+ max_burst_size -= n_segs;
+ }
+
+ if (!(tc->flags & TCP_CONN_SNDACK))
+ return n_segs;
+
+ tc->flags &= ~TCP_CONN_SNDACK;
+
+ /* We have retransmitted packets and no dupack */
+ if (n_segs && !tc->pending_dupacks)
+ return n_segs;
+
+ if (!max_burst_size)
+ {
+ tcp_program_ack (tc);
+ return max_burst_size;
+ }
+
+ n_segs += tcp_send_acks (tc, max_burst_size);
+
+ return n_segs;
+}
#endif /* CLIB_MARCH_VARIANT */
static void