}
void
-tcp_program_fastretransmit (tcp_connection_t * tc)
+tcp_program_retransmit (tcp_connection_t * tc)
{
- if (!(tc->flags & TCP_CONN_FRXT_PENDING))
+ if (!(tc->flags & TCP_CONN_RXT_PENDING))
{
session_add_self_custom_tx_evt (&tc->connection, 0);
- tc->flags |= TCP_CONN_FRXT_PENDING;
+ tc->flags |= TCP_CONN_RXT_PENDING;
}
}
if (!n_bytes)
return 0;
- if (tcp_in_fastrecovery (tc))
- {
- tc->snd_rxt_bytes += n_bytes;
- if (tc->flags & TCP_CONN_RATE_SAMPLE)
- tcp_bt_track_rxt (tc, start, start + n_bytes);
- }
+ tc->snd_rxt_bytes += n_bytes;
+
+ if (tc->flags & TCP_CONN_RATE_SAMPLE)
+ tcp_bt_track_rxt (tc, start, start + n_bytes);
tc->bytes_retrans += n_bytes;
tc->segs_retrans += 1;
TCP_EVT (TCP_EVT_CC_RTX, tc, offset, n_bytes);
+
return n_bytes;
}
+static void
+tcp_check_sack_reneging (tcp_connection_t * tc)
+{
+ sack_scoreboard_t *sb = &tc->sack_sb;
+ sack_scoreboard_hole_t *hole;
+
+ hole = scoreboard_first_hole (sb);
+ if (!sb->is_reneging && (!hole || hole->start == tc->snd_una))
+ return;
+
+ scoreboard_clear_reneging (sb, tc->snd_una, tc->snd_nxt);
+}
+
/**
* Reset congestion control, switch cwnd to loss window and try again.
*/
tcp_cc_init_rxt_timeout (tcp_connection_t * tc)
{
TCP_EVT (TCP_EVT_CC_EVT, tc, 6);
+
tc->prev_ssthresh = tc->ssthresh;
tc->prev_cwnd = tc->cwnd;
- /* Clear fast recovery state if needed */
- if (tcp_in_fastrecovery (tc))
- tcp_cc_fastrecovery_clear (tc);
+ /* If we entrered loss without fast recovery, notify cc algo of the
+ * congestion event such that it can update ssthresh and its state */
+ if (!tcp_in_fastrecovery (tc))
+ tcp_cc_congestion (tc);
- /* Let cc algo decide loss cwnd and ssthresh */
+ /* Let cc algo decide loss cwnd and ssthresh post unrecovered loss */
tcp_cc_loss (tc);
- /* Start again from the beginning */
- tc->snd_congestion = tc->snd_nxt;
- tc->rcv_dupacks = 0;
tc->rtt_ts = 0;
tc->cwnd_acc_bytes = 0;
tc->tr_occurences += 1;
- tcp_connection_tx_pacer_reset (tc, tc->cwnd, 2 * tc->snd_mss);
tcp_recovery_on (tc);
}
return;
}
- /* Increment RTO backoff (also equal to number of retries) and go back
- * to first un-acked byte */
- tc->rto_boff += 1;
+ if (tcp_opts_sack_permitted (&tc->rcv_opts))
+ tcp_check_sack_reneging (tc);
- /* TODO be less aggressive about clearing scoreboard */
- scoreboard_clear (&tc->sack_sb);
+ /* Update send congestion to make sure that rxt has data to send */
+ tc->snd_congestion = tc->snd_nxt;
- /* First retransmit timeout */
- if (tc->rto_boff == 1)
- {
- tcp_cc_init_rxt_timeout (tc);
- /* Record timestamp. Eifel detection algorithm RFC3522 */
- tc->snd_rxt_ts = tcp_tstamp (tc);
- }
-
- if (tc->flags & TCP_CONN_RATE_SAMPLE)
- tcp_bt_flush_samples (tc);
-
- /* If we've sent beyond snd_congestion, update it */
- tc->snd_congestion = seq_max (tc->snd_nxt, tc->snd_congestion);
- tc->snd_nxt = tc->snd_una;
-
- /* Send one segment. n_bytes may be zero due to buffer shortfall */
+ /* Send the first unacked segment. If we're short on buffers, return
+ * as soon as possible */
n_bytes = tcp_prepare_retransmit_segment (wrk, tc, 0, tc->snd_mss, &b);
if (!n_bytes)
{
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
tcp_retransmit_timer_force_update (tc);
+
+ tc->rto_boff += 1;
+ if (tc->rto_boff == 1)
+ {
+ tcp_cc_init_rxt_timeout (tc);
+ /* Record timestamp. Eifel detection algorithm RFC3522 */
+ tc->snd_rxt_ts = tcp_tstamp (tc);
+ }
+
+ if (tcp_opts_sack_permitted (&tc->rcv_opts))
+ scoreboard_init_high_rxt (&tc->sack_sb, tc->snd_una + tc->snd_mss);
+
+ tcp_program_retransmit (tc);
}
/* Retransmit SYN-ACK */
else if (tc->state == TCP_STATE_SYN_RCVD)
}
static int
-tcp_fast_retransmit_unsent (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
- u32 burst_size)
+tcp_transmit_unsent (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
+ u32 burst_size)
{
u32 offset, n_segs = 0, n_written, bi, available_wnd;
vlib_main_t *vm = wrk->vm;
return n_segs;
}
+/**
+ * Estimate send space using proportional rate reduction (RFC6937)
+ */
+static int
+tcp_fastrecovery_prr_snd_space (tcp_connection_t * tc)
+{
+ u32 pipe, prr_out;
+ int space;
+
+ pipe = tcp_flight_size (tc);
+ prr_out = tc->snd_rxt_bytes + (tc->snd_nxt - tc->snd_congestion);
+
+ if (pipe > tc->ssthresh)
+ {
+ space = ((int) tc->prr_delivered * ((f64) tc->ssthresh / tc->prev_cwnd))
+ - prr_out;
+ }
+ else
+ {
+ int limit = tc->prr_delivered - prr_out + tc->snd_mss;
+ space = clib_min (tc->ssthresh - pipe, limit);
+ }
+ space = clib_max (space, prr_out ? 0 : tc->snd_mss);
+ return space;
+}
+
#define scoreboard_rescue_rxt_valid(_sb, _tc) \
(seq_geq (_sb->rescue_rxt, _tc->snd_una) \
&& seq_leq (_sb->rescue_rxt, _tc->snd_congestion))
/**
- * Do fast retransmit with SACKs
+ * Do retransmit with SACKs
*/
-int
-tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
- u32 burst_size)
+static int
+tcp_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
+ u32 burst_size)
{
- u32 n_written = 0, offset, max_bytes, n_segs = 0, n_segs_now;
+ u32 n_written = 0, offset, max_bytes, n_segs = 0;
sack_scoreboard_hole_t *hole;
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b = 0;
int snd_space;
u8 snd_limited = 0, can_rescue = 0;
- ASSERT (tcp_in_fastrecovery (tc));
+ ASSERT (tcp_in_cong_recovery (tc));
+
+ if (tcp_in_recovery (tc))
+ snd_space = tcp_available_cc_snd_space (tc);
+ else
+ snd_space = tcp_fastrecovery_prr_snd_space (tc);
- snd_space = tcp_available_cc_snd_space (tc);
if (snd_space < tc->snd_mss)
{
- tcp_program_fastretransmit (tc);
+ /* We're cc constrained so don't accumulate tokens */
+ transport_connection_tx_pacer_reset_bucket (&tc->connection,
+ vm->
+ clib_time.last_cpu_time);
return 0;
}
&snd_limited);
if (!hole)
{
+ /* We are out of lost holes to retransmit so send some new data. */
if (max_deq)
{
+ u32 n_segs_new, av_window;
+ av_window = tc->snd_wnd - (tc->snd_nxt - tc->snd_una);
+ snd_space = clib_min (snd_space, av_window);
snd_space = clib_min (max_deq, snd_space);
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 (tc);
- n_segs += n_segs_now;
+ burst_size = clib_min (burst_size, TCP_RXT_MAX_BURST);
+ n_segs_new = tcp_transmit_unsent (wrk, tc, burst_size);
+ if (max_deq > n_segs_new * tc->snd_mss)
+ tcp_program_retransmit (tc);
+
+ n_segs += n_segs_new;
goto done;
}
- if (!can_rescue || scoreboard_rescue_rxt_valid (sb, tc))
+ if (tcp_in_recovery (tc) || !can_rescue
+ || scoreboard_rescue_rxt_valid (sb, tc))
break;
/* If rescue rxt undefined or less than snd_una then one segment of
}
if (hole)
- tcp_program_fastretransmit (tc);
+ tcp_program_retransmit (tc);
done:
+
return n_segs;
}
/**
* Fast retransmit without SACK info
*/
-int
-tcp_fast_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
- u32 burst_size)
+static int
+tcp_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
+ u32 burst_size)
{
u32 n_written = 0, offset = 0, bi, max_deq, n_segs_now;
vlib_main_t *vm = wrk->vm;
{
snd_space = clib_min (max_deq, snd_space);
burst_size = clib_min (burst_size - n_segs, snd_space / tc->snd_mss);
- n_segs_now = tcp_fast_retransmit_unsent (wrk, tc, burst_size);
+ n_segs_now = tcp_transmit_unsent (wrk, tc, burst_size);
if (max_deq > n_segs_now * tc->snd_mss)
- tcp_program_fastretransmit (tc);
+ tcp_program_retransmit (tc);
n_segs += n_segs_now;
}
/**
* Do fast retransmit
*/
-int
-tcp_fast_retransmit (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
- u32 burst_size)
+static int
+tcp_retransmit (tcp_worker_ctx_t * wrk, tcp_connection_t * tc, u32 burst_size)
{
if (tcp_opts_sack_permitted (&tc->rcv_opts))
- return tcp_fast_retransmit_sack (wrk, tc, burst_size);
+ return tcp_retransmit_sack (wrk, tc, burst_size);
else
- return tcp_fast_retransmit_no_sack (wrk, tc, burst_size);
+ return tcp_retransmit_no_sack (wrk, tc, burst_size);
}
static int
}
static int
-tcp_do_fastretransmit (tcp_connection_t * tc, u32 max_burst_size)
+tcp_do_retransmit (tcp_connection_t * tc, u32 max_burst_size)
{
u32 n_segs = 0, burst_size, sent_bytes, burst_bytes;
tcp_worker_ctx_t *wrk;
burst_size = clib_min (max_burst_size, burst_bytes / tc->snd_mss);
if (!burst_size)
{
- tcp_program_fastretransmit (tc);
+ tcp_program_retransmit (tc);
return 0;
}
- n_segs = tcp_fast_retransmit (wrk, tc, burst_size);
+ n_segs = tcp_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;
tcp_connection_t *tc = (tcp_connection_t *) conn;
u32 n_segs = 0;
- if (tcp_in_fastrecovery (tc) && (tc->flags & TCP_CONN_FRXT_PENDING))
+ if (tcp_in_cong_recovery (tc) && (tc->flags & TCP_CONN_RXT_PENDING))
{
- tc->flags &= ~TCP_CONN_FRXT_PENDING;
- n_segs = tcp_do_fastretransmit (tc, max_burst_size);
+ tc->flags &= ~TCP_CONN_RXT_PENDING;
+ n_segs = tcp_do_retransmit (tc, max_burst_size);
max_burst_size -= n_segs;
}
Code Review / vpp.git / blobdiff