hole = scoreboard_first_hole (sb);
if (hole)
- s = format (s, "\n%Uhead %u tail %u %u holes:\n", format_white_space,
- indent, sb->head, sb->tail, pool_elts (sb->holes));
+ s = format (s, "\n%Uhead %u tail %u %u holes:\n%U", format_white_space,
+ indent, sb->head, sb->tail, pool_elts (sb->holes),
+ format_white_space, indent);
while (hole)
{
- s = format (s, "%U%U", format_white_space, indent, format_tcp_sack_hole,
- hole, tc);
+ s = format (s, "%U", format_tcp_sack_hole, hole, tc);
hole = scoreboard_next_hole (sb, hole);
}
{
int snd_space, snt_limited;
- if (PREDICT_TRUE (!tcp_in_fastrecovery (tc)))
- {
- snd_space = tcp_available_output_snd_space (tc);
-
- /* If we haven't gotten dupacks or if we did and have gotten sacked
- * bytes then we can still send as per Limited Transmit (RFC3042) */
- if (PREDICT_FALSE (tc->rcv_dupacks != 0
- && (tcp_opts_sack_permitted (tc)
- && tc->sack_sb.last_sacked_bytes == 0)))
- {
- if (tc->rcv_dupacks == 1 && tc->limited_transmit != tc->snd_nxt)
- tc->limited_transmit = tc->snd_nxt;
- ASSERT (seq_leq (tc->limited_transmit, tc->snd_nxt));
+ if (PREDICT_FALSE (tcp_in_fastrecovery (tc)))
+ return 0;
- snt_limited = tc->snd_nxt - tc->limited_transmit;
- snd_space = clib_max (2 * tc->snd_mss - snt_limited, 0);
- }
- return tcp_round_snd_space (tc, snd_space);
- }
+ snd_space = tcp_available_output_snd_space (tc);
- /* RFC 5681: When previously unsent data is available and the new value of
- * cwnd and the receiver's advertised window allow, a TCP SHOULD send 1*SMSS
- * bytes of previously unsent data. */
- if (tcp_in_fastrecovery (tc) && !tcp_fastrecovery_sent_1_smss (tc))
+ /* If we haven't gotten dupacks or if we did and have gotten sacked
+ * bytes then we can still send as per Limited Transmit (RFC3042) */
+ if (PREDICT_FALSE (tc->rcv_dupacks != 0
+ && (tcp_opts_sack_permitted (tc)
+ && tc->sack_sb.last_sacked_bytes == 0)))
{
- if (tcp_available_cc_snd_space (tc) < tc->snd_mss)
- return 0;
- tcp_fastrecovery_1_smss_on (tc);
- return tc->snd_mss;
- }
+ if (tc->rcv_dupacks == 1 && tc->limited_transmit != tc->snd_nxt)
+ tc->limited_transmit = tc->snd_nxt;
+ ASSERT (seq_leq (tc->limited_transmit, tc->snd_nxt));
- return 0;
+ snt_limited = tc->snd_nxt - tc->limited_transmit;
+ snd_space = clib_max (2 * tc->snd_mss - snt_limited, 0);
+ }
+ return tcp_round_snd_space (tc, snd_space);
}
u32
sack_scoreboard_hole_t *
scoreboard_next_rxt_hole (sack_scoreboard_t * sb,
sack_scoreboard_hole_t * start,
- u8 have_sent_1_smss,
- u8 * can_rescue, u8 * snd_limited)
+ u8 have_unsent, u8 * can_rescue, u8 * snd_limited)
{
sack_scoreboard_hole_t *hole = 0;
}
else
{
- /* Rule (2): output takes care of transmitting new data */
- if (!have_sent_1_smss)
+ /* Rule (2): available unsent data */
+ if (have_unsent)
{
- hole = 0;
sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX;
+ return 0;
}
/* Rule (3): if hole not lost */
else if (seq_lt (hole->start, sb->high_sacked))
}
static void
-scoreboard_init_high_rxt (sack_scoreboard_t * sb, u32 seq)
+scoreboard_init_high_rxt (sack_scoreboard_t * sb, u32 snd_una)
{
sack_scoreboard_hole_t *hole;
hole = scoreboard_first_hole (sb);
if (hole)
{
- seq = seq_gt (seq, hole->start) ? seq : hole->start;
+ snd_una = seq_gt (snd_una, hole->start) ? snd_una : hole->start;
sb->cur_rxt_hole = sb->head;
}
- sb->high_rxt = seq;
+ sb->high_rxt = snd_una;
+ sb->rescue_rxt = snd_una - 1;
}
void
{
tc->cwnd = tc->ssthresh;
scoreboard_init_high_rxt (&tc->sack_sb, tc->snd_una);
- tc->sack_sb.rescue_rxt = tc->snd_una - 1;
}
else
{
tc->cwnd = tc->ssthresh + 3 * tc->snd_mss;
}
+ /* Constrain rate until we get a partial ack */
pacer_wnd = clib_max (0.1 * tc->cwnd, 2 * tc->snd_mss);
tcp_connection_tx_pacer_reset (tc, pacer_wnd,
0 /* start bucket */ );
* Legitimate ACK. 2) If PARTIAL ACK try to retransmit
*/
+ /* Update the pacing rate. For the first partial ack we move from
+ * the artificially constrained rate to the one after congestion */
+ tcp_connection_tx_pacer_update (tc);
+
/* XXX limit this only to first partial ack? */
tcp_retransmit_timer_force_update (tc);
{
/* Apparently all retransmitted holes have been acked */
tc->snd_rxt_bytes = 0;
+ tc->sack_sb.high_rxt = tc->snd_una;
}
}
else
{
+ tcp_fastrecovery_first_on (tc);
+ /* Reuse last bytes delivered to track total bytes acked */
+ tc->sack_sb.last_bytes_delivered += tc->bytes_acked;
if (tc->snd_rxt_bytes > tc->bytes_acked)
tc->snd_rxt_bytes -= tc->bytes_acked;
else
{
tcp_make_ack (tc, b);
*next = tcp_next_output (tc->c_is_ip4);
- *error = TCP_ERROR_ACK_INVALID;
+ *error = TCP_ERROR_ACK_FUTURE;
TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 0,
vnet_buffer (b)->tcp.ack_number);
return -1;
vnet_buffer (b)->tcp.ack_number);
tc->snd_nxt = vnet_buffer (b)->tcp.ack_number;
- *error = TCP_ERROR_ACK_FUTURE;
}
/* If old ACK, probably it's an old dupack */
}
/**
- * Build a retransmit segment
+ * Allocate a new buffer and build a new tcp segment
*
- * @return the number of bytes in the segment or 0 if there's nothing to
- * retransmit
+ * @param wrk tcp worker
+ * @param tc connection for which the segment will be allocated
+ * @param offset offset of the first byte in the tx fifo
+ * @param max_deq_byte segment size
+ * @param[out] b pointer to buffer allocated
+ *
+ * @return the number of bytes in the segment or 0 if buffer cannot be
+ * allocated or no data available
*/
-static u32
-tcp_prepare_retransmit_segment (tcp_worker_ctx_t * wrk,
- tcp_connection_t * tc, u32 offset,
- u32 max_deq_bytes, vlib_buffer_t ** b)
+static int
+tcp_prepare_segment (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
+ u32 offset, u32 max_deq_bytes, vlib_buffer_t ** b)
{
u32 bytes_per_buffer = vnet_get_tcp_main ()->bytes_per_buffer;
+ u32 bi, seg_size;
vlib_main_t *vm = wrk->vm;
int n_bytes = 0;
- u32 start, bi, available_bytes, seg_size;
u8 *data;
- ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
- ASSERT (max_deq_bytes != 0);
-
- /*
- * Make sure we can retransmit something
- */
- available_bytes = session_tx_fifo_max_dequeue (&tc->connection);
- ASSERT (available_bytes >= offset);
- available_bytes -= offset;
- if (!available_bytes)
- return 0;
- max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
- max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
-
- /* Start is beyond snd_congestion */
- start = tc->snd_una + offset;
- if (seq_geq (start, tc->snd_congestion))
- goto done;
-
- /* Don't overshoot snd_congestion */
- if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
- {
- max_deq_bytes = tc->snd_congestion - start;
- if (max_deq_bytes == 0)
- goto done;
- }
-
seg_size = max_deq_bytes + MAX_HDRS_LEN;
/*
ASSERT (n_bytes > 0);
ASSERT (((*b)->current_data + (*b)->current_length) <= bytes_per_buffer);
+ return n_bytes;
+}
+
+/**
+ * Build a retransmit segment
+ *
+ * @return the number of bytes in the segment or 0 if there's nothing to
+ * retransmit
+ */
+static u32
+tcp_prepare_retransmit_segment (tcp_worker_ctx_t * wrk,
+ tcp_connection_t * tc, u32 offset,
+ u32 max_deq_bytes, vlib_buffer_t ** b)
+{
+ u32 start, available_bytes;
+ int n_bytes = 0;
+
+ ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
+ ASSERT (max_deq_bytes != 0);
+
+ /*
+ * Make sure we can retransmit something
+ */
+ available_bytes = session_tx_fifo_max_dequeue (&tc->connection);
+ ASSERT (available_bytes >= offset);
+ available_bytes -= offset;
+ if (!available_bytes)
+ return 0;
+
+ max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
+ max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
+
+ /* Start is beyond snd_congestion */
+ start = tc->snd_una + offset;
+ if (seq_geq (start, tc->snd_congestion))
+ goto done;
+
+ /* Don't overshoot snd_congestion */
+ if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
+ {
+ max_deq_bytes = tc->snd_congestion - start;
+ if (max_deq_bytes == 0)
+ goto done;
+ }
+
+ n_bytes = tcp_prepare_segment (wrk, tc, offset, max_deq_bytes, b);
+ if (!n_bytes)
+ return 0;
+
if (tcp_in_fastrecovery (tc))
tc->snd_rxt_bytes += n_bytes;
return 0;
}
+static int
+tcp_fast_retransmit_unsent (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
+ u32 burst_size)
+{
+ u32 offset, n_segs = 0, n_written, bi;
+ vlib_main_t *vm = wrk->vm;
+ vlib_buffer_t *b = 0;
+
+ tc->snd_nxt = tc->snd_una_max;
+ offset = tc->snd_una_max - tc->snd_una;
+ while (n_segs < burst_size)
+ {
+ n_written = tcp_prepare_segment (wrk, tc, offset, tc->snd_mss, &b);
+ if (!n_written)
+ goto done;
+
+ bi = vlib_get_buffer_index (vm, b);
+ tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
+ offset += n_written;
+ n_segs += 1;
+ }
+
+done:
+ return n_segs;
+}
+
+#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
*/
tcp_fast_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;
+ sack_scoreboard_hole_t *hole;
vlib_main_t *vm = wrk->vm;
- u32 n_written = 0, offset, max_bytes, n_segs = 0;
vlib_buffer_t *b = 0;
- sack_scoreboard_hole_t *hole;
sack_scoreboard_t *sb;
u32 bi, old_snd_nxt;
int snd_space;
+ u32 max_deq;
u8 snd_limited = 0, can_rescue = 0;
ASSERT (tcp_in_fastrecovery (tc));
- old_snd_nxt = tc->snd_nxt;
- sb = &tc->sack_sb;
snd_space = tcp_available_cc_snd_space (tc);
- hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
-
if (snd_space < tc->snd_mss)
{
tcp_program_fastretransmit (wrk, tc);
- goto done;
+ return 0;
}
TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
+ old_snd_nxt = tc->snd_nxt;
+ sb = &tc->sack_sb;
+ hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
+
+ max_deq = session_tx_fifo_max_dequeue (&tc->connection);
+ max_deq -= tc->snd_una_max - tc->snd_una;
+
while (snd_space > 0 && n_segs < burst_size)
{
- hole = scoreboard_next_rxt_hole (sb, hole,
- tcp_fastrecovery_sent_1_smss (tc),
- &can_rescue, &snd_limited);
+ hole = scoreboard_next_rxt_hole (sb, hole, max_deq, &can_rescue,
+ &snd_limited);
if (!hole)
{
- if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
- || seq_gt (sb->rescue_rxt,
- tc->snd_congestion)))
+ if (max_deq)
{
- if (tcp_fastrecovery_first (tc))
- break;
-
- /* We tend to lose the first segment. Try re-resending
- * it but only once and after we've tried everything */
- hole = scoreboard_first_hole (sb);
- if (hole && hole->start == tc->snd_una)
- {
- tcp_retransmit_first_unacked (wrk, tc);
- tcp_fastrecovery_first_on (tc);
- n_segs += 1;
- }
- break;
+ 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 (wrk, tc);
+ n_segs += n_segs_now;
+ goto done;
}
+ if (!can_rescue || scoreboard_rescue_rxt_valid (sb, tc))
+ break;
+
/* If rescue rxt undefined or less than snd_una then one segment of
* up to SMSS octets that MUST include the highest outstanding
* unSACKed sequence number SHOULD be returned, and RescueRxt set to
max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
if (max_bytes == 0)
break;
+
offset = sb->high_rxt - tc->snd_una;
tc->snd_nxt = sb->high_rxt;
n_written = tcp_prepare_retransmit_segment (wrk, tc, offset, max_bytes,
&b);
+ ASSERT (n_written <= snd_space);
/* Nothing left to retransmit */
if (n_written == 0)
break;
bi = vlib_get_buffer_index (vm, b);
- sb->high_rxt += n_written;
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
- ASSERT (n_written <= snd_space);
+
+ sb->high_rxt += n_written;
snd_space -= n_written;
n_segs += 1;
}
tcp_fast_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
u32 burst_size)
{
- u32 n_written = 0, offset = 0, bi, old_snd_nxt;
+ u32 n_written = 0, offset = 0, bi, old_snd_nxt, max_deq, n_segs_now;
vlib_main_t *vm = wrk->vm;
int snd_space, n_segs = 0;
vlib_buffer_t *b;
ASSERT (tcp_in_fastrecovery (tc));
TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
-
- /* Start resending from first un-acked segment */
old_snd_nxt = tc->snd_nxt;
- tc->snd_nxt = tc->snd_una;
- snd_space = tcp_available_cc_snd_space (tc);
+ if (!tcp_fastrecovery_first (tc))
+ goto send_unsent;
+
+ /* RFC 6582: [If a partial ack], retransmit the first unacknowledged
+ * segment. */
+ snd_space = tc->sack_sb.last_bytes_delivered;
+ tc->snd_nxt = tc->snd_una;
while (snd_space > 0 && n_segs < burst_size)
{
- offset += n_written;
- n_written = tcp_prepare_retransmit_segment (wrk, tc, offset, snd_space,
- &b);
+ n_written = tcp_prepare_retransmit_segment (wrk, tc, offset,
+ tc->snd_mss, &b);
/* Nothing left to retransmit */
if (n_written == 0)
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
snd_space -= n_written;
+ offset += n_written;
n_segs += 1;
}
- /* More data to resend */
- if (seq_lt (tc->snd_nxt, tc->snd_congestion))
- tcp_program_fastretransmit (wrk, tc);
+ if (n_segs == burst_size)
+ goto done;
+
+send_unsent:
- /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
+ /* RFC 6582: Send a new segment if permitted by the new value of cwnd. */
+ snd_space = tcp_available_cc_snd_space (tc);
+ if (snd_space < tc->snd_mss)
+ goto done;
+
+ max_deq = session_tx_fifo_max_dequeue (&tc->connection);
+ max_deq -= tc->snd_una_max - tc->snd_una;
+ if (max_deq)
+ {
+ 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 (wrk, tc);
+ n_segs += n_segs_now;
+ }
+
+ /* Restore snd_nxt */
tc->snd_nxt = old_snd_nxt;
+done:
+ tcp_fastrecovery_first_off (tc);
return n_segs;
}
Code Review / vpp.git / commitdiff