always_inline int
tcp_segment_check_paws (tcp_connection_t * tc)
{
- return tcp_opts_tstamp (&tc->opt) && tc->tsval_recent
- && timestamp_lt (tc->opt.tsval, tc->tsval_recent);
+ return tcp_opts_tstamp (&tc->rcv_opts) && tc->tsval_recent
+ && timestamp_lt (tc->rcv_opts.tsval, tc->tsval_recent);
}
/**
* then the TSval from the segment is copied to TS.Recent;
* otherwise, the TSval is ignored.
*/
- if (tcp_opts_tstamp (&tc->opt) && tc->tsval_recent
+ if (tcp_opts_tstamp (&tc->rcv_opts) && tc->tsval_recent
&& seq_leq (seq, tc->rcv_las) && seq_leq (tc->rcv_las, seq_end))
{
- tc->tsval_recent = tc->opt.tsval;
+ tc->tsval_recent = tc->rcv_opts.tsval;
tc->tsval_recent_age = tcp_time_now ();
}
}
if (PREDICT_FALSE (!tcp_ack (th0) && !tcp_rst (th0) && !tcp_syn (th0)))
return -1;
- if (PREDICT_FALSE (tcp_options_parse (th0, &tc0->opt)))
+ if (PREDICT_FALSE (tcp_options_parse (th0, &tc0->rcv_opts)))
{
return -1;
}
if (tcp_segment_check_paws (tc0))
{
- clib_warning ("paws failed");
+ if (CLIB_DEBUG > 2)
+ {
+ clib_warning ("paws failed\n%U", format_tcp_connection, tc0, 2);
+ clib_warning ("seq %u seq_end %u ack %u",
+ vnet_buffer (b0)->tcp.seq_number - tc0->irs,
+ vnet_buffer (b0)->tcp.seq_end - tc0->irs,
+ vnet_buffer (b0)->tcp.ack_number - tc0->iss);
+ }
TCP_EVT_DBG (TCP_EVT_PAWS_FAIL, tc0, vnet_buffer (b0)->tcp.seq_number,
vnet_buffer (b0)->tcp.seq_end);
/* If segment in window, save timestamp */
tcp_update_timestamp (tc0, vnet_buffer (b0)->tcp.seq_number,
vnet_buffer (b0)->tcp.seq_end);
-
return 0;
}
}
}
+void
+tcp_update_rto (tcp_connection_t * tc)
+{
+ tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX);
+}
+
/** Update RTT estimate and RTO timer
*
* Measure RTT: We have two sources of RTT measurements: TSOPT and ACK
u32 mrtt = 0;
u8 rtx_acked;
- /* Determine if only rtx bytes are acked. TODO fast retransmit */
+ /* Determine if only rtx bytes are acked. TODO XXX fast retransmit */
rtx_acked = tc->rto_boff && (tc->bytes_acked <= tc->snd_mss);
/* Karn's rule, part 1. Don't use retransmitted segments to estimate
* snd_una, i.e., the left side of the send window:
* seq_lt (tc->snd_una, ack). Note: last condition could be dropped, we don't
* try to update rtt for dupacks */
- else if (tcp_opts_tstamp (&tc->opt) && tc->opt.tsecr && tc->bytes_acked)
+ else if (tcp_opts_tstamp (&tc->rcv_opts) && tc->rcv_opts.tsecr
+ && tc->bytes_acked)
{
- mrtt = tcp_time_now () - tc->opt.tsecr;
+ mrtt = tcp_time_now () - tc->rcv_opts.tsecr;
}
/* Allow measuring of a new RTT */
return 0;
tcp_estimate_rtt (tc, mrtt);
- tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX);
+ tcp_update_rto (tc);
return 0;
}
static void
tcp_dequeue_acked (tcp_connection_t * tc, u32 ack)
{
- /* Dequeue the newly ACKed bytes */
- stream_session_dequeue_drop (&tc->connection, tc->bytes_acked);
+ /* Dequeue the newly ACKed add SACKed bytes */
+ stream_session_dequeue_drop (&tc->connection,
+ tc->bytes_acked + tc->sack_sb.snd_una_adv);
+
+ tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
/* Update rtt and rto */
tcp_update_rtt (tc, ack);
+
+ /* If everything has been acked, stop retransmit timer
+ * otherwise update. */
+ tcp_retransmit_timer_update (tc);
}
/**
- * Check if dupack as per RFC5681 Sec. 2
- *
- * This works only if called before updating snd_wnd.
- * */
-always_inline u8
-tcp_ack_is_dupack (tcp_connection_t * tc, vlib_buffer_t * b, u32 new_snd_wnd)
+ * Check if duplicate ack as per RFC5681 Sec. 2
+ */
+static u8
+tcp_ack_is_dupack (tcp_connection_t * tc, vlib_buffer_t * b, u32 prev_snd_wnd,
+ u32 prev_snd_una)
{
- return ((vnet_buffer (b)->tcp.ack_number == tc->snd_una)
+ return ((vnet_buffer (b)->tcp.ack_number == prev_snd_una)
&& seq_gt (tc->snd_una_max, tc->snd_una)
&& (vnet_buffer (b)->tcp.seq_end == vnet_buffer (b)->tcp.seq_number)
- && (new_snd_wnd == tc->snd_wnd));
+ && (prev_snd_wnd == tc->snd_wnd));
+}
+
+/**
+ * Checks if ack is a congestion control event.
+ */
+static u8
+tcp_ack_is_cc_event (tcp_connection_t * tc, vlib_buffer_t * b,
+ u32 prev_snd_wnd, u32 prev_snd_una, u8 * is_dack)
+{
+ /* Check if ack is duplicate. Per RFC 6675, ACKs that SACK new data are
+ * defined to be 'duplicate' */
+ *is_dack = tc->sack_sb.last_sacked_bytes
+ || tcp_ack_is_dupack (tc, b, prev_snd_wnd, prev_snd_una);
+
+ return (*is_dack || tcp_in_cong_recovery (tc));
}
void
next = pool_elt_at_index (sb->holes, hole->next);
next->prev = hole->prev;
}
+ else
+ {
+ sb->tail = hole->prev;
+ }
if (hole->prev != TCP_INVALID_SACK_HOLE_INDEX)
{
sb->head = hole->next;
}
+ if (scoreboard_hole_index (sb, hole) == sb->cur_rxt_hole)
+ sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX;
+
pool_put (sb->holes, hole);
}
return hole;
}
+void
+scoreboard_update_lost (tcp_connection_t * tc, sack_scoreboard_t * sb)
+{
+ sack_scoreboard_hole_t *hole, *prev;
+ u32 bytes = 0, blks = 0;
+
+ sb->lost_bytes = 0;
+ hole = scoreboard_last_hole (sb);
+ if (!hole)
+ return;
+
+ if (seq_gt (sb->high_sacked, hole->end))
+ {
+ bytes = sb->high_sacked - hole->end;
+ blks = 1;
+ }
+
+ while ((prev = scoreboard_prev_hole (sb, hole))
+ && (bytes < (TCP_DUPACK_THRESHOLD - 1) * tc->snd_mss
+ && blks < TCP_DUPACK_THRESHOLD))
+ {
+ bytes += hole->start - prev->end;
+ blks++;
+ hole = prev;
+ }
+
+ hole = prev;
+ while (hole)
+ {
+ sb->lost_bytes += scoreboard_hole_bytes (hole);
+ hole->is_lost = 1;
+ hole = scoreboard_prev_hole (sb, hole);
+ }
+}
+
+/**
+ * Figure out the next hole to retransmit
+ *
+ * Follows logic proposed in RFC6675 Sec. 4, NextSeg()
+ */
+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)
+{
+ sack_scoreboard_hole_t *hole = 0;
+
+ hole = start ? start : scoreboard_first_hole (sb);
+ while (hole && seq_leq (hole->end, sb->high_rxt) && hole->is_lost)
+ hole = scoreboard_next_hole (sb, hole);
+
+ /* Nothing, return */
+ if (!hole)
+ {
+ sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX;
+ return 0;
+ }
+
+ /* Rule (1): if higher than rxt, less than high_sacked and lost */
+ if (hole->is_lost && seq_lt (hole->start, sb->high_sacked))
+ {
+ sb->cur_rxt_hole = scoreboard_hole_index (sb, hole);
+ }
+ else
+ {
+ /* Rule (2): output takes care of transmitting new data */
+ if (!have_sent_1_smss)
+ {
+ hole = 0;
+ sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX;
+ }
+ /* Rule (3): if hole not lost */
+ else if (seq_lt (hole->start, sb->high_sacked))
+ {
+ *snd_limited = 1;
+ sb->cur_rxt_hole = scoreboard_hole_index (sb, hole);
+ }
+ /* Rule (4): if hole beyond high_sacked */
+ else
+ {
+ ASSERT (seq_geq (hole->start, sb->high_sacked));
+ *snd_limited = 1;
+ *can_rescue = 1;
+ /* HighRxt MUST NOT be updated */
+ return 0;
+ }
+ }
+
+ if (hole && seq_lt (sb->high_rxt, hole->start))
+ sb->high_rxt = hole->start;
+
+ return hole;
+}
+
+void
+scoreboard_init_high_rxt (sack_scoreboard_t * sb)
+{
+ sack_scoreboard_hole_t *hole;
+ hole = scoreboard_first_hole (sb);
+ sb->high_rxt = hole->start;
+ sb->cur_rxt_hole = sb->head;
+}
+
void
tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
{
sack_scoreboard_t *sb = &tc->sack_sb;
sack_block_t *blk, tmp;
sack_scoreboard_hole_t *hole, *next_hole, *last_hole, *new_hole;
- u32 blk_index = 0, old_sacked_bytes, delivered_bytes, hole_index;
+ u32 blk_index = 0, old_sacked_bytes, hole_index;
int i, j;
sb->last_sacked_bytes = 0;
sb->snd_una_adv = 0;
old_sacked_bytes = sb->sacked_bytes;
- delivered_bytes = 0;
+ sb->last_bytes_delivered = 0;
- if (!tcp_opts_sack (&tc->opt) && sb->head == TCP_INVALID_SACK_HOLE_INDEX)
+ if (!tcp_opts_sack (&tc->rcv_opts)
+ && sb->head == TCP_INVALID_SACK_HOLE_INDEX)
return;
/* Remove invalid blocks */
- blk = tc->opt.sacks;
- while (blk < vec_end (tc->opt.sacks))
+ blk = tc->rcv_opts.sacks;
+ while (blk < vec_end (tc->rcv_opts.sacks))
{
if (seq_lt (blk->start, blk->end)
&& seq_gt (blk->start, tc->snd_una)
blk++;
continue;
}
- vec_del1 (tc->opt.sacks, blk - tc->opt.sacks);
+ vec_del1 (tc->rcv_opts.sacks, blk - tc->rcv_opts.sacks);
}
/* Add block for cumulative ack */
{
tmp.start = tc->snd_una;
tmp.end = ack;
- vec_add1 (tc->opt.sacks, tmp);
+ vec_add1 (tc->rcv_opts.sacks, tmp);
}
- if (vec_len (tc->opt.sacks) == 0)
+ if (vec_len (tc->rcv_opts.sacks) == 0)
return;
/* Make sure blocks are ordered */
- for (i = 0; i < vec_len (tc->opt.sacks); i++)
- for (j = i + 1; j < vec_len (tc->opt.sacks); j++)
- if (seq_lt (tc->opt.sacks[j].start, tc->opt.sacks[i].start))
+ for (i = 0; i < vec_len (tc->rcv_opts.sacks); i++)
+ for (j = i + 1; j < vec_len (tc->rcv_opts.sacks); j++)
+ if (seq_lt (tc->rcv_opts.sacks[j].start, tc->rcv_opts.sacks[i].start))
{
- tmp = tc->opt.sacks[i];
- tc->opt.sacks[i] = tc->opt.sacks[j];
- tc->opt.sacks[j] = tmp;
+ tmp = tc->rcv_opts.sacks[i];
+ tc->rcv_opts.sacks[i] = tc->rcv_opts.sacks[j];
+ tc->rcv_opts.sacks[j] = tmp;
}
if (sb->head == TCP_INVALID_SACK_HOLE_INDEX)
last_hole = scoreboard_insert_hole (sb, TCP_INVALID_SACK_HOLE_INDEX,
tc->snd_una, tc->snd_una_max);
sb->tail = scoreboard_hole_index (sb, last_hole);
- tmp = tc->opt.sacks[vec_len (tc->opt.sacks) - 1];
- sb->max_byte_sacked = tmp.end;
+ tmp = tc->rcv_opts.sacks[vec_len (tc->rcv_opts.sacks) - 1];
+ sb->high_sacked = tmp.end;
}
else
{
/* If we have holes but snd_una_max is beyond the last hole, update
* last hole end */
- tmp = tc->opt.sacks[vec_len (tc->opt.sacks) - 1];
+ tmp = tc->rcv_opts.sacks[vec_len (tc->rcv_opts.sacks) - 1];
last_hole = scoreboard_last_hole (sb);
- if (seq_gt (tc->snd_una_max, sb->max_byte_sacked)
+ if (seq_gt (tc->snd_una_max, sb->high_sacked)
&& seq_gt (tc->snd_una_max, last_hole->end))
last_hole->end = tc->snd_una_max;
}
/* Walk the holes with the SACK blocks */
hole = pool_elt_at_index (sb->holes, sb->head);
- while (hole && blk_index < vec_len (tc->opt.sacks))
+ while (hole && blk_index < vec_len (tc->rcv_opts.sacks))
{
- blk = &tc->opt.sacks[blk_index];
+ blk = &tc->rcv_opts.sacks[blk_index];
if (seq_leq (blk->start, hole->start))
{
{
/* Bytes lost because snd_wnd left edge advances */
if (next_hole && seq_leq (next_hole->start, ack))
- delivered_bytes += next_hole->start - hole->end;
+ sb->last_bytes_delivered += next_hole->start - hole->end;
else
- delivered_bytes += ack - hole->end;
+ sb->last_bytes_delivered += ack - hole->end;
}
else
{
last_hole = scoreboard_last_hole (sb);
/* keep track of max byte sacked for when the last hole
* is acked */
- if (seq_gt (hole->end, sb->max_byte_sacked))
- sb->max_byte_sacked = hole->end;
+ if (seq_gt (hole->end, sb->high_sacked))
+ sb->high_sacked = hole->end;
}
/* snd_una needs to be advanced */
sb->snd_una_adv = next_hole->start - ack;
/* all these can be delivered */
- delivered_bytes += sb->snd_una_adv;
+ sb->last_bytes_delivered += sb->snd_una_adv;
}
else if (!next_hole)
{
- sb->snd_una_adv = sb->max_byte_sacked - ack;
- delivered_bytes += sb->snd_una_adv;
+ sb->snd_una_adv = sb->high_sacked - ack;
+ sb->last_bytes_delivered += sb->snd_una_adv;
}
}
}
blk_index++;
- hole = scoreboard_next_hole (sb, hole);
}
- else
+ else if (seq_leq (blk->start, hole->end))
{
sb->sacked_bytes += hole->end - blk->start;
hole->end = blk->start;
- hole = scoreboard_next_hole (sb, hole);
}
+
+ hole = scoreboard_next_hole (sb, hole);
}
}
sb->last_sacked_bytes = sb->sacked_bytes - old_sacked_bytes;
- sb->sacked_bytes -= delivered_bytes;
+ sb->sacked_bytes -= sb->last_bytes_delivered;
+ scoreboard_update_lost (tc, sb);
}
-/** Update snd_wnd
+/**
+ * Try to update snd_wnd based on feedback received from peer.
*
- * If (SND.WL1 < SEG.SEQ or (SND.WL1 = SEG.SEQ and SND.WL2 =< SEG.ACK)), set
- * SND.WND <- SEG.WND, set SND.WL1 <- SEG.SEQ, and set SND.WL2 <- SEG.ACK */
+ * If successful, and new window is 'effectively' 0, activate persist
+ * timer.
+ */
static void
tcp_update_snd_wnd (tcp_connection_t * tc, u32 seq, u32 ack, u32 snd_wnd)
{
+ /* If (SND.WL1 < SEG.SEQ or (SND.WL1 = SEG.SEQ and SND.WL2 =< SEG.ACK)), set
+ * SND.WND <- SEG.WND, set SND.WL1 <- SEG.SEQ, and set SND.WL2 <- SEG.ACK */
if (seq_lt (tc->snd_wl1, seq)
|| (tc->snd_wl1 == seq && seq_leq (tc->snd_wl2, ack)))
{
tc->snd_wl2 = ack;
TCP_EVT_DBG (TCP_EVT_SND_WND, tc);
- /* Set probe timer if we just got 0 wnd */
if (tc->snd_wnd < tc->snd_mss)
{
- if (!tcp_timer_is_active (tc, TCP_TIMER_PERSIST))
+ /* Set persist timer if not set and we just got 0 wnd */
+ if (!tcp_timer_is_active (tc, TCP_TIMER_PERSIST)
+ && !tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT))
tcp_persist_timer_set (tc);
}
else
- tcp_persist_timer_reset (tc);
+ {
+ tcp_persist_timer_reset (tc);
+ if (!tcp_in_recovery (tc) && tc->rto_boff > 0)
+ {
+ tc->rto_boff = 0;
+ tcp_update_rto (tc);
+ }
+ }
}
}
void
-tcp_cc_congestion (tcp_connection_t * tc)
+tcp_cc_init_congestion (tcp_connection_t * tc)
{
- tc->snd_congestion = tc->snd_nxt;
+ tcp_fastrecovery_on (tc);
+ tc->snd_congestion = tc->snd_una_max;
tc->cc_algo->congestion (tc);
TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 4);
}
-void
-tcp_cc_recover (tcp_connection_t * tc)
+static void
+tcp_cc_recovery_exit (tcp_connection_t * tc)
{
- /* TODO: check if time to recover was small. It might be that RTO popped
- * too soon.
- */
+ /* Deflate rto */
+ tcp_update_rto (tc);
+ tc->rto_boff = 0;
+ tc->snd_rxt_ts = 0;
+ tcp_recovery_off (tc);
+}
+void
+tcp_cc_fastrecovery_exit (tcp_connection_t * tc)
+{
tc->cc_algo->recovered (tc);
+ tc->snd_rxt_bytes = 0;
+ tc->rcv_dupacks = 0;
+ tcp_fastrecovery_off (tc);
+ tcp_fastrecovery_1_smss_off (tc);
+}
- tc->rtx_bytes = 0;
+static void
+tcp_cc_congestion_undo (tcp_connection_t * tc)
+{
+ tc->cwnd = tc->prev_cwnd;
+ tc->ssthresh = tc->prev_ssthresh;
+ tc->snd_nxt = tc->snd_una_max;
tc->rcv_dupacks = 0;
- tc->snd_nxt = tc->snd_una;
+ if (tcp_in_recovery (tc))
+ tcp_cc_recovery_exit (tc);
+ ASSERT (tc->rto_boff == 0);
+ /* TODO extend for fastrecovery */
+}
- tc->cc_algo->rcv_ack (tc);
- tc->tsecr_last_ack = tc->opt.tsecr;
+static u8
+tcp_cc_is_spurious_retransmit (tcp_connection_t * tc)
+{
+ return (tc->snd_rxt_ts
+ && tcp_opts_tstamp (&tc->rcv_opts)
+ && timestamp_lt (tc->rcv_opts.tsecr, tc->snd_rxt_ts));
+}
- tcp_cong_recovery_off (tc);
+int
+tcp_cc_recover (tcp_connection_t * tc)
+{
+ ASSERT (tcp_in_cong_recovery (tc));
+ if (tcp_cc_is_spurious_retransmit (tc))
+ {
+ tcp_cc_congestion_undo (tc);
+ return 1;
+ }
+
+ if (tcp_in_recovery (tc))
+ tcp_cc_recovery_exit (tc);
+ else if (tcp_in_fastrecovery (tc))
+ tcp_cc_fastrecovery_exit (tc);
+
+ ASSERT (tc->rto_boff == 0);
+ ASSERT (!tcp_in_cong_recovery (tc));
TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3);
+ return 0;
}
static void
-tcp_cc_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b)
+tcp_cc_update (tcp_connection_t * tc, vlib_buffer_t * b)
+{
+ ASSERT (!tcp_in_cong_recovery (tc));
+
+ /* Congestion avoidance */
+ tc->cc_algo->rcv_ack (tc);
+ tc->tsecr_last_ack = tc->rcv_opts.tsecr;
+
+ /* If a cumulative ack, make sure dupacks is 0 */
+ tc->rcv_dupacks = 0;
+
+ /* When dupacks hits the threshold we only enter fast retransmit if
+ * cumulative ack covers more than snd_congestion. Should snd_una
+ * wrap this test may fail under otherwise valid circumstances.
+ * Therefore, proactively update snd_congestion when wrap detected. */
+ if (PREDICT_FALSE
+ (seq_leq (tc->snd_congestion, tc->snd_una - tc->bytes_acked)
+ && seq_gt (tc->snd_congestion, tc->snd_una)))
+ tc->snd_congestion = tc->snd_una - 1;
+}
+
+static u8
+tcp_should_fastrecover_sack (tcp_connection_t * tc)
{
- u8 partial_ack;
- u32 bytes_advanced;
+ return (TCP_DUPACK_THRESHOLD - 1) * tc->snd_mss < tc->sack_sb.sacked_bytes;
+}
- if (tcp_in_fastrecovery (tc))
+static u8
+tcp_should_fastrecover (tcp_connection_t * tc)
+{
+ return (tc->rcv_dupacks == TCP_DUPACK_THRESHOLD
+ || tcp_should_fastrecover_sack (tc));
+}
+
+static void
+tcp_cc_handle_event (tcp_connection_t * tc, u32 is_dack)
+{
+ /*
+ * Duplicate ACK. Check if we should enter fast recovery, or if already in
+ * it account for the bytes that left the network.
+ */
+ if (is_dack)
{
- partial_ack = seq_lt (tc->snd_una, tc->snd_congestion);
- if (!partial_ack)
+ ASSERT (tc->snd_una != tc->snd_una_max
+ || tc->sack_sb.last_sacked_bytes);
+ tc->rcv_dupacks++;
+
+ if (tc->rcv_dupacks > TCP_DUPACK_THRESHOLD && !tc->bytes_acked)
{
- /* Clear retransmitted bytes. */
- tcp_cc_recover (tc);
+ ASSERT (tcp_in_fastrecovery (tc));
+ /* Pure duplicate ack. If some data got acked, it's handled lower */
+ tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK);
+ return;
}
- else
+ else if (tcp_should_fastrecover (tc))
{
- TCP_EVT_DBG (TCP_EVT_CC_PACK, tc);
+ /* Things are already bad */
+ if (tcp_in_cong_recovery (tc))
+ {
+ tc->rcv_dupacks = 0;
+ goto partial_ack_test;
+ }
- /* Clear retransmitted bytes. XXX should we clear all? */
- tc->rtx_bytes = 0;
+ /* If of of the two conditions lower hold, reset dupacks
+ * 1) Cumulative ack does not cover more than congestion threshold
+ * 2) RFC6582 heuristic to avoid multiple fast retransmits
+ */
+ if (seq_leq (tc->snd_una, tc->snd_congestion)
+ || tc->rcv_opts.tsecr != tc->tsecr_last_ack)
+ {
+ tc->rcv_dupacks = 0;
+ return;
+ }
+
+ tcp_cc_init_congestion (tc);
+ tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK);
- tc->cc_algo->rcv_cong_ack (tc, TCP_CC_PARTIALACK);
+ /* The first segment MUST be retransmitted */
+ tcp_retransmit_first_unacked (tc);
- /* In case snd_nxt is still in the past and output tries to
- * shove some new bytes */
- tc->snd_nxt = tc->snd_una_max;
+ /* Post retransmit update cwnd to ssthresh and account for the
+ * three segments that have left the network and should've been
+ * buffered at the receiver XXX */
+ tc->cwnd = tc->ssthresh + tc->rcv_dupacks * tc->snd_mss;
- /* XXX need proper RFC6675 support */
- if (tc->sack_sb.last_sacked_bytes && !tcp_in_recovery (tc))
+ /* If cwnd allows, send more data */
+ if (tcp_opts_sack_permitted (&tc->rcv_opts)
+ && scoreboard_first_hole (&tc->sack_sb))
{
- tcp_fast_retransmit (tc);
+ scoreboard_init_high_rxt (&tc->sack_sb);
+ tcp_fast_retransmit_sack (tc);
}
else
{
- /* Retransmit first unacked segment */
- tcp_retransmit_first_unacked (tc);
+ tcp_fast_retransmit_no_sack (tc);
}
+
+ return;
}
- }
- else
- {
- tc->cc_algo->rcv_ack (tc);
- tc->tsecr_last_ack = tc->opt.tsecr;
- tc->rcv_dupacks = 0;
- if (tcp_in_recovery (tc))
+ else if (!tc->bytes_acked
+ || (tc->bytes_acked && !tcp_in_cong_recovery (tc)))
{
- bytes_advanced = tc->bytes_acked + tc->sack_sb.snd_una_adv;
- tc->rtx_bytes -= clib_min (bytes_advanced, tc->rtx_bytes);
- tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX);
- if (seq_geq (tc->snd_una, tc->snd_congestion))
- {
- tc->rtx_bytes = 0;
- tcp_recovery_off (tc);
- }
+ tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK);
+ return;
}
+ else
+ goto partial_ack;
}
-}
-static void
-tcp_cc_rcv_dupack (tcp_connection_t * tc, u32 ack)
-{
-// ASSERT (seq_geq(tc->snd_una, ack));
+partial_ack_test:
+
+ if (!tc->bytes_acked)
+ return;
+
+partial_ack:
+ /*
+ * Legitimate ACK. 1) See if we can exit recovery
+ */
+ /* XXX limit this only to first partial ack? */
+ tcp_retransmit_timer_update (tc);
- tc->rcv_dupacks++;
- if (tc->rcv_dupacks == TCP_DUPACK_THRESHOLD)
+ if (seq_geq (tc->snd_una, tc->snd_congestion))
{
- /* RFC6582 NewReno heuristic to avoid multiple fast retransmits */
- if (tc->opt.tsecr != tc->tsecr_last_ack)
- {
- tc->rcv_dupacks = 0;
- return;
- }
+ /* If spurious return, we've already updated everything */
+ if (tcp_cc_recover (tc))
+ return;
+
+ tc->snd_nxt = tc->snd_una_max;
- tcp_fastrecovery_on (tc);
+ /* Treat as congestion avoidance ack */
+ tc->cc_algo->rcv_ack (tc);
+ tc->tsecr_last_ack = tc->rcv_opts.tsecr;
+ return;
+ }
+
+ /*
+ * Legitimate ACK. 2) If PARTIAL ACK try to retransmit
+ */
+ TCP_EVT_DBG (TCP_EVT_CC_PACK, tc);
+
+ /* RFC6675: If the incoming ACK is a cumulative acknowledgment,
+ * reset dupacks to 0 */
+ tc->rcv_dupacks = 0;
- /* Handle congestion and dupack */
- tcp_cc_congestion (tc);
- tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK);
+ tcp_retransmit_first_unacked (tc);
- tcp_fast_retransmit (tc);
+ /* Post RTO timeout don't try anything fancy */
+ if (tcp_in_recovery (tc))
+ return;
- /* Post retransmit update cwnd to ssthresh and account for the
- * three segments that have left the network and should've been
- * buffered at the receiver */
- tc->cwnd = tc->ssthresh + TCP_DUPACK_THRESHOLD * tc->snd_mss;
+ /* Remove retransmitted bytes that have been delivered */
+ if (tc->sack_sb.last_bytes_delivered
+ && seq_gt (tc->sack_sb.high_rxt, tc->snd_una))
+ {
+ /* If we have sacks and we haven't gotten an ack beyond high_rxt,
+ * remove sacked bytes delivered */
+ tc->snd_rxt_bytes -= tc->sack_sb.last_bytes_delivered;
}
- else if (tc->rcv_dupacks > TCP_DUPACK_THRESHOLD)
+ else
{
- ASSERT (tcp_in_fastrecovery (tc));
-
- tc->cc_algo->rcv_cong_ack (tc, TCP_CC_DUPACK);
+ /* Either all retransmitted holes have been acked, or we're
+ * "in the blind" and retransmitting segment by segment */
+ tc->snd_rxt_bytes = 0;
}
+
+ tc->cc_algo->rcv_cong_ack (tc, TCP_CC_PARTIALACK);
+
+ /*
+ * Since this was a partial ack, try to retransmit some more data
+ */
+ tcp_fast_retransmit (tc);
}
void
tc->cc_algo->init (tc);
}
+/**
+ * Process incoming ACK
+ */
static int
tcp_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b,
tcp_header_t * th, u32 * next, u32 * error)
{
- u32 new_snd_wnd;
+ u32 prev_snd_wnd, prev_snd_una;
+ u8 is_dack;
/* If the ACK acks something not yet sent (SEG.ACK > SND.NXT) */
- if (seq_gt (vnet_buffer (b)->tcp.ack_number, tc->snd_nxt))
+ if (PREDICT_FALSE (seq_gt (vnet_buffer (b)->tcp.ack_number, tc->snd_nxt)))
{
/* If we have outstanding data and this is within the window, accept it,
* probably retransmit has timed out. Otherwise ACK segment and then
}
/* If old ACK, probably it's an old dupack */
- if (seq_lt (vnet_buffer (b)->tcp.ack_number, tc->snd_una))
+ if (PREDICT_FALSE (seq_lt (vnet_buffer (b)->tcp.ack_number, tc->snd_una)))
{
*error = TCP_ERROR_ACK_OLD;
TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 1,
if (tcp_in_fastrecovery (tc) && tc->rcv_dupacks == TCP_DUPACK_THRESHOLD)
{
TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc);
- tcp_cc_rcv_dupack (tc, vnet_buffer (b)->tcp.ack_number);
+ tcp_cc_handle_event (tc, 1);
}
/* Don't drop yet */
return 0;
}
- if (tcp_opts_sack_permitted (&tc->opt))
- tcp_rcv_sacks (tc, vnet_buffer (b)->tcp.ack_number);
-
- new_snd_wnd = clib_net_to_host_u16 (th->window) << tc->snd_wscale;
-
- if (tcp_ack_is_dupack (tc, b, new_snd_wnd))
- {
- TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc, 1);
- tcp_cc_rcv_dupack (tc, vnet_buffer (b)->tcp.ack_number);
- *error = TCP_ERROR_ACK_DUP;
- return -1;
- }
-
/*
- * Valid ACK
+ * Looks okay, process feedback
*/
- tc->bytes_acked = vnet_buffer (b)->tcp.ack_number - tc->snd_una;
- tc->snd_una = vnet_buffer (b)->tcp.ack_number + tc->sack_sb.snd_una_adv;
+ TCP_EVT_DBG (TCP_EVT_ACK_RCVD, tc);
+
+ if (tcp_opts_sack_permitted (&tc->rcv_opts))
+ tcp_rcv_sacks (tc, vnet_buffer (b)->tcp.ack_number);
- /* Dequeue ACKed data and update RTT */
- tcp_dequeue_acked (tc, vnet_buffer (b)->tcp.ack_number);
+ prev_snd_wnd = tc->snd_wnd;
+ prev_snd_una = tc->snd_una;
tcp_update_snd_wnd (tc, vnet_buffer (b)->tcp.seq_number,
- vnet_buffer (b)->tcp.ack_number, new_snd_wnd);
+ vnet_buffer (b)->tcp.ack_number,
+ clib_net_to_host_u16 (th->window) << tc->snd_wscale);
+ tc->bytes_acked = vnet_buffer (b)->tcp.ack_number - tc->snd_una;
+ tc->snd_una = vnet_buffer (b)->tcp.ack_number + tc->sack_sb.snd_una_adv;
+ tcp_validate_txf_size (tc, tc->bytes_acked);
- /* If some of our sent bytes have been acked, update cc and retransmit
- * timer. */
if (tc->bytes_acked)
- {
- TCP_EVT_DBG (TCP_EVT_ACK_RCVD, tc);
+ tcp_dequeue_acked (tc, vnet_buffer (b)->tcp.ack_number);
- /* Updates congestion control (slow start/congestion avoidance) */
- tcp_cc_rcv_ack (tc, b);
+ /*
+ * Check if we have congestion event
+ */
- /* If everything has been acked, stop retransmit timer
- * otherwise update. */
- if (tc->snd_una == tc->snd_una_max)
- tcp_retransmit_timer_reset (tc);
- else
- tcp_retransmit_timer_update (tc);
+ if (tcp_ack_is_cc_event (tc, b, prev_snd_wnd, prev_snd_una, &is_dack))
+ {
+ tcp_cc_handle_event (tc, is_dack);
+ *error = TCP_ERROR_ACK_DUP;
+ TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc, 1);
+ return vnet_buffer (b)->tcp.data_len ? 0 : -1;
}
+ /*
+ * Update congestion control (slow start/congestion avoidance)
+ */
+ tcp_cc_update (tc, b);
+
return 0;
}
}
/* Update SACK list if need be */
- if (tcp_opts_sack_permitted (&tc->opt))
+ if (tcp_opts_sack_permitted (&tc->rcv_opts))
{
/* Remove SACK blocks that have been delivered */
tcp_update_sack_list (tc, tc->rcv_nxt, tc->rcv_nxt);
TCP_EVT_DBG (TCP_EVT_INPUT, tc, 1, data_len, data_len);
/* Update SACK list if in use */
- if (tcp_opts_sack_permitted (&tc->opt))
+ if (tcp_opts_sack_permitted (&tc->rcv_opts))
{
ooo_segment_t *newest;
u32 start, end;
u32 n_left_to_next;
vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
-
while (n_left_from > 0 && n_left_to_next > 0)
{
u32 bi0;
}
th0 = tcp_buffer_hdr (b0);
-
is_fin = (th0->flags & TCP_FLAG_FIN) != 0;
/* SYNs, FINs and data consume sequence numbers */
errors = session_manager_flush_enqueue_events (my_thread_index);
tcp_established_inc_counter (vm, is_ip4, TCP_ERROR_EVENT_FIFO_FULL, errors);
-
return from_frame->n_vectors;
}
new_tc0->irs = seq0;
/* Parse options */
- if (tcp_options_parse (tcp0, &new_tc0->opt))
+ if (tcp_options_parse (tcp0, &new_tc0->rcv_opts))
goto drop;
- if (tcp_opts_tstamp (&new_tc0->opt))
+ if (tcp_opts_tstamp (&new_tc0->rcv_opts))
{
- new_tc0->tsval_recent = new_tc0->opt.tsval;
+ new_tc0->tsval_recent = new_tc0->rcv_opts.tsval;
new_tc0->tsval_recent_age = tcp_time_now ();
}
- if (tcp_opts_wscale (&new_tc0->opt))
- new_tc0->snd_wscale = new_tc0->opt.wscale;
+ if (tcp_opts_wscale (&new_tc0->rcv_opts))
+ new_tc0->snd_wscale = new_tc0->rcv_opts.wscale;
/* No scaling */
new_tc0->snd_wnd = clib_net_to_host_u16 (tcp0->window);
/* Initialize session variables */
tc0->snd_una = vnet_buffer (b0)->tcp.ack_number;
tc0->snd_wnd = clib_net_to_host_u16 (tcp0->window)
- << tc0->opt.wscale;
+ << tc0->rcv_opts.wscale;
tc0->snd_wl1 = vnet_buffer (b0)->tcp.seq_number;
tc0->snd_wl2 = vnet_buffer (b0)->tcp.ack_number;
break;
case TCP_STATE_LAST_ACK:
- /* The only thing that can arrive in this state is an
+ /* The only thing that [should] arrive in this state is an
* acknowledgment of our FIN. If our FIN is now acknowledged,
* delete the TCB, enter the CLOSED state, and return. */
if (!tcp_rcv_ack_is_acceptable (tc0, b0))
goto drop;
+ /* Apparently our FIN was lost */
+ if (tcp_fin (tcp0))
+ {
+ /* Don't "make" fin since that increments snd_nxt */
+ tcp_send_fin (tc0);
+ goto drop;
+ }
+
tc0->state = TCP_STATE_CLOSED;
/* Don't delete the connection/session yet. Instead, wait a
* retransmission of the remote FIN. Acknowledge it, and restart
* the 2 MSL timeout. */
- /* TODO */
+ if (tcp_rcv_ack (tc0, b0, tcp0, &next0, &error0))
+ goto drop;
+
+ tcp_make_ack (tc0, b0);
+ tcp_timer_reset (tc0, TCP_TIMER_WAITCLOSE);
+ tcp_timer_set (tc0, TCP_TIMER_WAITCLOSE, TCP_2MSL_TIME);
+
goto drop;
+
break;
default:
ASSERT (0);
goto drop;
}
- if (tcp_options_parse (th0, &child0->opt))
+ if (tcp_options_parse (th0, &child0->rcv_opts))
{
goto drop;
}
/* RFC1323: TSval timestamps sent on {SYN} and {SYN,ACK}
* segments are used to initialize PAWS. */
- if (tcp_opts_tstamp (&child0->opt))
+ if (tcp_opts_tstamp (&child0->rcv_opts))
{
- child0->tsval_recent = child0->opt.tsval;
+ child0->tsval_recent = child0->rcv_opts.tsval;
child0->tsval_recent_age = tcp_time_now ();
}
- if (tcp_opts_wscale (&child0->opt))
- child0->snd_wscale = child0->opt.wscale;
+ if (tcp_opts_wscale (&child0->rcv_opts))
+ child0->snd_wscale = child0->rcv_opts.wscale;
/* No scaling */
child0->snd_wnd = clib_net_to_host_u16 (th0->window);
vlib_add_trace (vm, node, b0, sizeof (*t0));
tcp_set_rx_trace_data (t0, tc0, tcp0, b0, is_ip4);
}
-
vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
n_left_to_next, bi0, next0);
}
_(FIN_WAIT_2, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
TCP_ERROR_NONE);
_(LAST_ACK, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(LAST_ACK, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(LAST_ACK, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
+ TCP_ERROR_NONE);
_(LAST_ACK, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(TIME_WAIT, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(TIME_WAIT, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
+ TCP_ERROR_NONE);
_(CLOSED, TCP_FLAG_ACK, TCP_INPUT_NEXT_RESET, TCP_ERROR_CONNECTION_CLOSED);
_(CLOSED, TCP_FLAG_RST, TCP_INPUT_NEXT_DROP, TCP_ERROR_CONNECTION_CLOSED);
#undef _
Code Review / vpp.git / blobdiff