diff options
Diffstat (limited to 'src/vnet/tcp/tcp_sack.c')
| -rw-r--r-- | src/vnet/tcp/tcp_sack.c | 62 |
1 files changed, 43 insertions, 19 deletions
diff --git a/src/vnet/tcp/tcp_sack.c b/src/vnet/tcp/tcp_sack.c index b9e1166d779..8f51b517361 100644 --- a/src/vnet/tcp/tcp_sack.c +++ b/src/vnet/tcp/tcp_sack.c @@ -88,10 +88,23 @@ scoreboard_insert_hole (sack_scoreboard_t * sb, u32 prev_index, } always_inline void -scoreboard_update_sacked_rxt (sack_scoreboard_t * sb, u32 start, u32 end, - u8 has_rxt) +scoreboard_update_sacked (sack_scoreboard_t * sb, u32 start, u32 end, + u8 has_rxt, u16 snd_mss) { - if (!has_rxt || seq_geq (start, sb->high_rxt)) + if (!has_rxt) + { + /* Sequence was not retransmitted but it was sacked. Estimate reorder + * only if not in congestion recovery */ + if (seq_lt (start, sb->high_sacked)) + { + u32 reord = (sb->high_sacked - start + snd_mss - 1) / snd_mss; + reord = clib_min (reord, TCP_MAX_SACK_REORDER); + sb->reorder = clib_max (sb->reorder, reord); + } + return; + } + + if (seq_geq (start, sb->high_rxt)) return; sb->rxt_sacked += @@ -125,8 +138,14 @@ scoreboard_update_bytes (sack_scoreboard_t * sb, u32 ack, u32 snd_mss) blks = 1; } - while (sacked < (TCP_DUPACK_THRESHOLD - 1) * snd_mss - && blks < TCP_DUPACK_THRESHOLD) + /* As per RFC 6675 a sequence number is lost if: + * DupThresh discontiguous SACKed sequences have arrived above + * 'SeqNum' or more than (DupThresh - 1) * SMSS bytes with sequence + * numbers greater than 'SeqNum' have been SACKed. + * To avoid spurious retransmits, use reordering estimate instead of + * DupThresh to detect loss. + */ + while (sacked <= (sb->reorder - 1) * snd_mss && blks < sb->reorder) { if (right->is_lost) sb->lost_bytes += scoreboard_hole_bytes (right); @@ -251,6 +270,7 @@ scoreboard_init (sack_scoreboard_t * sb) sb->head = TCP_INVALID_SACK_HOLE_INDEX; sb->tail = TCP_INVALID_SACK_HOLE_INDEX; sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX; + sb->reorder = TCP_DUPACK_THRESHOLD; } void @@ -270,6 +290,7 @@ scoreboard_clear (sack_scoreboard_t * sb) sb->last_lost_bytes = 0; sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX; sb->is_reneging = 0; + sb->reorder = TCP_DUPACK_THRESHOLD; } void @@ -307,7 +328,7 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack) sack_scoreboard_hole_t *hole, *next_hole; sack_scoreboard_t *sb = &tc->sack_sb; sack_block_t *blk, *rcv_sacks; - u32 blk_index = 0, i, j; + u32 blk_index = 0, i, j, high_sacked; u8 has_rxt; sb->last_sacked_bytes = 0; @@ -391,8 +412,9 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack) hole = scoreboard_insert_hole (sb, TCP_INVALID_SACK_HOLE_INDEX, tc->snd_una, tc->snd_nxt); sb->tail = scoreboard_hole_index (sb, hole); + sb->high_sacked = tc->snd_una; } - sb->high_sacked = rcv_sacks[vec_len (rcv_sacks) - 1].end; + high_sacked = rcv_sacks[vec_len (rcv_sacks) - 1].end; } else { @@ -412,11 +434,10 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack) tc->snd_nxt); } } - /* Keep track of max byte sacked for when the last hole * is acked */ - sb->high_sacked = seq_max (rcv_sacks[vec_len (rcv_sacks) - 1].end, - sb->high_sacked); + high_sacked = seq_max (rcv_sacks[vec_len (rcv_sacks) - 1].end, + sb->high_sacked); } /* Walk the holes with the SACK blocks */ @@ -442,7 +463,8 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack) /* If covered by ack, compute delivered bytes */ if (blk->end == ack) { - u32 sacked = next_hole ? next_hole->start : sb->high_sacked; + u32 sacked = next_hole ? next_hole->start : + seq_max (sb->high_sacked, hole->end); if (PREDICT_FALSE (seq_lt (ack, sacked))) { sb->last_bytes_delivered += ack - hole->end; @@ -454,8 +476,8 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack) sb->is_reneging = 0; } } - scoreboard_update_sacked_rxt (sb, hole->start, hole->end, - has_rxt); + scoreboard_update_sacked (sb, hole->start, hole->end, + has_rxt, tc->snd_mss); scoreboard_remove_hole (sb, hole); hole = next_hole; } @@ -464,8 +486,8 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack) { if (seq_gt (blk->end, hole->start)) { - scoreboard_update_sacked_rxt (sb, hole->start, blk->end, - has_rxt); + scoreboard_update_sacked (sb, hole->start, blk->end, + has_rxt, tc->snd_mss); hole->start = blk->end; } blk_index++; @@ -482,23 +504,25 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack) /* Pool might've moved */ hole = scoreboard_get_hole (sb, hole_index); hole->end = blk->start; + next_hole->is_lost = hole->is_lost; - scoreboard_update_sacked_rxt (sb, blk->start, blk->end, - has_rxt); + scoreboard_update_sacked (sb, blk->start, blk->end, + has_rxt, tc->snd_mss); blk_index++; ASSERT (hole->next == scoreboard_hole_index (sb, next_hole)); } else if (seq_lt (blk->start, hole->end)) { - scoreboard_update_sacked_rxt (sb, blk->start, hole->end, - has_rxt); + scoreboard_update_sacked (sb, blk->start, hole->end, + has_rxt, tc->snd_mss); hole->end = blk->start; } hole = scoreboard_next_hole (sb, hole); } } + sb->high_sacked = high_sacked; scoreboard_update_bytes (sb, ack, tc->snd_mss); ASSERT (sb->last_sacked_bytes <= sb->sacked_bytes || tcp_in_recovery (tc)); |