summaryrefslogtreecommitdiffstats
path: root/src/vnet/tcp/tcp_output.c
diff options
context:
space:
mode:
authorFlorin Coras <fcoras@cisco.com>2019-03-12 18:58:54 -0700
committerDamjan Marion <dmarion@me.com>2019-03-22 17:30:29 +0000
commit4759683744d079f868a6bcca8084eba8466620d7 (patch)
tree6795035edf69463107dfbaa54eae3183cdc62356 /src/vnet/tcp/tcp_output.c
parent881d13ede7336e5b16601033e5dd9aeb94c795e3 (diff)
tcp: improve handling of snd_nxt
- avoid changing snd_nxt when doing fast retransmits - use snd_una_max only to keep track of the max seq number sent - simplify future ack testing Change-Id: I3580ad3aefe30128486c3375d0ac3f3f62c04c5e Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src/vnet/tcp/tcp_output.c')
-rw-r--r--src/vnet/tcp/tcp_output.c95
1 files changed, 38 insertions, 57 deletions
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index ce7b50ac3e6..4b38649c171 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -183,7 +183,7 @@ tcp_update_rcv_wnd (tcp_connection_t * tc)
/**
* Compute and return window to advertise, scaled as per RFC1323
*/
-static u32
+static inline u32
tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state)
{
if (state < TCP_STATE_ESTABLISHED)
@@ -1052,14 +1052,14 @@ tcp_send_fin (tcp_connection_t * tc)
fin_snt = tc->flags & TCP_CONN_FINSNT;
if (fin_snt)
- tc->snd_nxt = tc->snd_una;
+ tc->snd_nxt -= 1;
if (PREDICT_FALSE (!vlib_buffer_alloc (vm, &bi, 1)))
{
/* Out of buffers so program fin retransmit ASAP */
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT, 1);
if (fin_snt)
- tc->snd_nxt = tc->snd_una_max;
+ tc->snd_nxt += 1;
else
/* Make sure retransmit retries a fin not data */
tc->flags |= TCP_CONN_FINSNT;
@@ -1072,18 +1072,13 @@ tcp_send_fin (tcp_connection_t * tc)
tcp_make_fin (tc, b);
tcp_enqueue_to_output_now (wrk, b, bi, tc->c_is_ip4);
TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc);
-
+ /* Account for the FIN */
+ tc->snd_nxt += 1;
if (!fin_snt)
{
tc->flags |= TCP_CONN_FINSNT;
tc->flags &= ~TCP_CONN_FINPNDG;
- /* Account for the FIN */
- tc->snd_una_max += 1;
- tc->snd_nxt = tc->snd_una_max;
- }
- else
- {
- tc->snd_nxt = tc->snd_una_max;
+ tc->snd_una_max = seq_max (tc->snd_una_max, tc->snd_nxt);
}
}
@@ -1092,8 +1087,8 @@ tcp_send_fin (tcp_connection_t * tc)
* for segments with data, not for 'control' packets.
*/
always_inline void
-tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
- tcp_state_t next_state, u8 compute_opts, u8 maybe_burst)
+tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b, u32 snd_nxt,
+ u8 compute_opts, u8 maybe_burst, u8 update_snd_nxt)
{
u8 tcp_hdr_opts_len, flags = TCP_FLAG_ACK;
u32 advertise_wnd, data_len;
@@ -1115,15 +1110,15 @@ tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
if (maybe_burst)
advertise_wnd = tc->rcv_wnd >> tc->rcv_wscale;
else
- advertise_wnd = tcp_window_to_advertise (tc, next_state);
+ advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED);
if (PREDICT_FALSE (tc->flags & TCP_CONN_PSH_PENDING))
{
- if (seq_geq (tc->psh_seq, tc->snd_nxt)
- && seq_lt (tc->psh_seq, tc->snd_nxt + data_len))
+ if (seq_geq (tc->psh_seq, snd_nxt)
+ && seq_lt (tc->psh_seq, snd_nxt + data_len))
flags |= TCP_FLAG_PSH;
}
- th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt,
+ th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, snd_nxt,
tc->rcv_nxt, tcp_hdr_opts_len, flags,
advertise_wnd);
@@ -1143,7 +1138,8 @@ tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
* Update connection variables
*/
- tc->snd_nxt += data_len;
+ if (update_snd_nxt)
+ tc->snd_nxt += data_len;
tc->rcv_las = tc->rcv_nxt;
TCP_EVT_DBG (TCP_EVT_PKTIZE, tc);
@@ -1153,9 +1149,9 @@ u32
tcp_session_push_header (transport_connection_t * tconn, vlib_buffer_t * b)
{
tcp_connection_t *tc = (tcp_connection_t *) tconn;
- tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, /* compute opts */ 0,
- /* burst */ 1);
- tc->snd_una_max = tc->snd_nxt;
+ tcp_push_hdr_i (tc, b, tc->snd_nxt, /* compute opts */ 0, /* burst */ 1,
+ /* update_snd_nxt */ 1);
+ tc->snd_una_max = seq_max (tc->snd_nxt, tc->snd_una_max);
ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd));
tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
/* If not tracking an ACK, start tracking */
@@ -1322,9 +1318,8 @@ tcp_prepare_segment (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
max_deq_bytes);
ASSERT (n_bytes == max_deq_bytes);
b[0]->current_length = n_bytes;
- tcp_push_hdr_i (tc, *b, tc->state, /* compute opts */ 0, /* burst */ 0);
- if (seq_gt (tc->snd_nxt, tc->snd_una_max))
- tc->snd_una_max = tc->snd_nxt;
+ tcp_push_hdr_i (tc, *b, tc->snd_una + offset, /* compute opts */ 0,
+ /* burst */ 0, /* update_snd_nxt */ 0);
}
/* Split mss into multiple buffers */
else
@@ -1381,9 +1376,8 @@ tcp_prepare_segment (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
b[0]->total_length_not_including_first_buffer += n_peeked;
}
- tcp_push_hdr_i (tc, *b, tc->state, /* compute opts */ 0, /* burst */ 0);
- if (seq_gt (tc->snd_nxt, tc->snd_una_max))
- tc->snd_una_max = tc->snd_nxt;
+ tcp_push_hdr_i (tc, *b, tc->snd_una + offset, /* compute opts */ 0,
+ /* burst */ 0, /* update_snd_nxt */ 0);
if (PREDICT_FALSE (n_bufs))
{
@@ -1475,7 +1469,7 @@ tcp_rxt_timeout_cc (tcp_connection_t * tc)
/* Start again from the beginning */
tc->cc_algo->congestion (tc);
tc->cwnd = tcp_loss_wnd (tc);
- tc->snd_congestion = tc->snd_una_max;
+ tc->snd_congestion = tc->snd_nxt;
tc->rtt_ts = 0;
tc->cwnd_acc_bytes = 0;
tcp_connection_tx_pacer_reset (tc, tc->cwnd, 2 * tc->snd_mss);
@@ -1527,7 +1521,7 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
/* Shouldn't be here. This condition is tricky because it has to take
* into account boff > 0 due to persist timeout. */
- if ((tc->rto_boff == 0 && tc->snd_una == tc->snd_una_max)
+ if ((tc->rto_boff == 0 && tc->snd_una == tc->snd_nxt)
|| (tc->rto_boff > 0 && seq_geq (tc->snd_una, tc->snd_congestion)
&& !tcp_flight_size (tc)))
{
@@ -1555,10 +1549,9 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn)
scoreboard_clear (&tc->sack_sb);
/* If we've sent beyond snd_congestion, update it */
- if (seq_gt (tc->snd_una_max, tc->snd_congestion))
- tc->snd_congestion = tc->snd_una_max;
+ tc->snd_congestion = seq_max (tc->snd_nxt, tc->snd_congestion);
- tc->snd_una_max = tc->snd_nxt = tc->snd_una;
+ tc->snd_nxt = tc->snd_una;
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
/* Send one segment. Note that n_bytes may be zero due to buffer
@@ -1695,7 +1688,7 @@ tcp_timer_persist_handler (u32 index)
return;
available_bytes = transport_max_tx_dequeue (&tc->connection);
- offset = tc->snd_una_max - tc->snd_una;
+ offset = tc->snd_nxt - tc->snd_una;
/* Reprogram persist if no new bytes available to send. We may have data
* next time */
@@ -1737,8 +1730,9 @@ tcp_timer_persist_handler (u32 index)
|| tc->snd_nxt == tc->snd_una_max
|| tc->rto_boff > 1));
- tcp_push_hdr_i (tc, b, tc->state, /* compute opts */ 0, /* burst */ 0);
- tc->snd_una_max = tc->snd_nxt;
+ tcp_push_hdr_i (tc, b, tc->snd_nxt, /* compute opts */ 0,
+ /* burst */ 0, /* update_snd_nxt */ 1);
+ tc->snd_una_max = seq_max (tc->snd_nxt, tc->snd_una_max);
tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
@@ -1752,12 +1746,9 @@ tcp_timer_persist_handler (u32 index)
int
tcp_retransmit_first_unacked (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
{
- u32 bi, old_snd_nxt, n_bytes;
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b;
-
- old_snd_nxt = tc->snd_nxt;
- tc->snd_nxt = tc->snd_una;
+ u32 bi, n_bytes;
TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1);
@@ -1767,7 +1758,6 @@ tcp_retransmit_first_unacked (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
bi = vlib_get_buffer_index (vm, b);
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
- tc->snd_nxt = old_snd_nxt;
return 0;
}
@@ -1780,8 +1770,7 @@ tcp_fast_retransmit_unsent (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
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;
+ offset = tc->snd_nxt - tc->snd_una;
while (n_segs < burst_size)
{
n_written = tcp_prepare_segment (wrk, tc, offset, tc->snd_mss, &b);
@@ -1792,6 +1781,9 @@ tcp_fast_retransmit_unsent (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
offset += n_written;
n_segs += 1;
+
+ tc->snd_nxt += n_written;
+ tc->snd_una_max = seq_max (tc->snd_nxt, tc->snd_una_max);
}
done:
@@ -1814,9 +1806,8 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
vlib_main_t *vm = wrk->vm;
vlib_buffer_t *b = 0;
sack_scoreboard_t *sb;
- u32 bi, old_snd_nxt;
+ u32 bi, max_deq;
int snd_space;
- u32 max_deq;
u8 snd_limited = 0, can_rescue = 0;
ASSERT (tcp_in_fastrecovery (tc));
@@ -1829,12 +1820,11 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
}
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 = transport_max_tx_dequeue (&tc->connection);
- max_deq -= tc->snd_una_max - tc->snd_una;
+ max_deq -= tc->snd_nxt - tc->snd_una;
while (snd_space > 0 && n_segs < burst_size)
{
@@ -1867,7 +1857,6 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
max_bytes = clib_min (max_bytes, snd_space);
offset = tc->snd_congestion - tc->snd_una - max_bytes;
sb->rescue_rxt = tc->snd_congestion;
- tc->snd_nxt = tc->snd_una + offset;
n_written = tcp_prepare_retransmit_segment (wrk, tc, offset,
max_bytes, &b);
if (!n_written)
@@ -1885,7 +1874,6 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
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);
@@ -1906,8 +1894,6 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
tcp_program_fastretransmit (wrk, tc);
done:
- /* If window allows, send 1 SMSS of new data */
- tc->snd_nxt = old_snd_nxt;
return n_segs;
}
@@ -1918,14 +1904,13 @@ int
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, max_deq, n_segs_now;
+ u32 n_written = 0, offset = 0, bi, 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);
- old_snd_nxt = tc->snd_nxt;
if (!tcp_fastrecovery_first (tc))
goto send_unsent;
@@ -1933,7 +1918,6 @@ tcp_fast_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
/* 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)
{
n_written = tcp_prepare_retransmit_segment (wrk, tc, offset,
@@ -1961,7 +1945,7 @@ send_unsent:
goto done;
max_deq = transport_max_tx_dequeue (&tc->connection);
- max_deq -= tc->snd_una_max - tc->snd_una;
+ max_deq -= tc->snd_nxt - tc->snd_una;
if (max_deq)
{
snd_space = clib_min (max_deq, snd_space);
@@ -1972,9 +1956,6 @@ send_unsent:
n_segs += n_segs_now;
}
- /* Restore snd_nxt */
- tc->snd_nxt = old_snd_nxt;
-
done:
tcp_fastrecovery_first_off (tc);
return n_segs;