break;
case TCP_STATE_SYN_SENT:
/* Do not program ntf because the connection is half-open */
+ tc->rst_state = tc->state;
tcp_handle_rst (tc);
break;
case TCP_STATE_ESTABLISHED:
/**
* Compute smoothed RTT as per VJ's '88 SIGCOMM and RFC6298
*
- * Note that although the original article, srtt and rttvar are scaled
+ * Note that although in the original article srtt and rttvar are scaled
* to minimize round-off errors, here we don't. Instead, we rely on
* better precision time measurements.
*
- * TODO support us rtt resolution
+ * A known limitation of the algorithm is that a drop in rtt results in a
+ * rttvar increase and bigger RTO.
+ *
+ * mrtt must be provided in @ref TCP_TICK multiples, i.e., in us. Note that
+ * timestamps are measured as ms ticks so they must be converted before
+ * calling this function.
*/
static void
tcp_estimate_rtt (tcp_connection_t * tc, u32 mrtt)
{
int err, diff;
- if (tc->srtt != 0)
- {
- err = mrtt - tc->srtt;
+ err = mrtt - tc->srtt;
+ tc->srtt = clib_max ((int) tc->srtt + (err >> 3), 1);
+ diff = (clib_abs (err) - (int) tc->rttvar) >> 2;
+ tc->rttvar = clib_max ((int) tc->rttvar + diff, 1);
+}
- /* XXX Drop in RTT results in RTTVAR increase and bigger RTO.
- * The increase should be bound */
- tc->srtt = clib_max ((int) tc->srtt + (err >> 3), 1);
- diff = (clib_abs (err) - (int) tc->rttvar) >> 2;
- tc->rttvar = clib_max ((int) tc->rttvar + diff, 1);
- }
- else
- {
- /* First measurement. */
- tc->srtt = mrtt;
- tc->rttvar = mrtt >> 1;
- }
+static inline void
+tcp_estimate_rtt_us (tcp_connection_t * tc, f64 mrtt)
+{
+ tc->mrtt_us = tc->mrtt_us + (mrtt - tc->mrtt_us) * 0.125;
}
/**
- * Update RTT estimate and RTO timer
+ * Update rtt estimate
+ *
+ * We have potentially three sources of rtt measurements:
*
- * Measure RTT: We have two sources of RTT measurements: TSOPT and ACK
- * timing. Middle boxes are known to fiddle with TCP options so we
- * should give higher priority to ACK timing.
+ * TSOPT difference between current and echoed timestamp. It has ms
+ * precision and can be computed per ack
+ * ACK timing one sequence number is tracked per rtt with us (micro second)
+ * precision.
+ * rate sample if enabled, all outstanding bytes are tracked with us
+ * precision. Every ack and sack are a rtt sample
*
- * This should be called only if previously sent bytes have been acked.
+ * Middle boxes are known to fiddle with TCP options so we give higher
+ * priority to ACK timing.
*
- * return 1 if valid rtt 0 otherwise
+ * For now, rate sample rtts are only used under congestion.
*/
static int
tcp_update_rtt (tcp_connection_t * tc, tcp_rate_sample_t * rs, u32 ack)
if (tcp_in_cong_recovery (tc))
{
/* Accept rtt estimates for samples that have not been retransmitted */
- if ((tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
- && !(rs->flags & TCP_BTS_IS_RXT))
- {
- mrtt = rs->rtt_time * THZ;
- goto estimate_rtt;
- }
- goto done;
+ if (!(tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
+ || (rs->flags & TCP_BTS_IS_RXT))
+ goto done;
+ if (rs->rtt_time)
+ tcp_estimate_rtt_us (tc, rs->rtt_time);
+ mrtt = rs->rtt_time * THZ;
+ goto estimate_rtt;
}
if (tc->rtt_ts && seq_geq (ack, tc->rtt_seq))
{
f64 sample = tcp_time_now_us (tc->c_thread_index) - tc->rtt_ts;
- tc->mrtt_us = tc->mrtt_us + (sample - tc->mrtt_us) * 0.125;
+ tcp_estimate_rtt_us (tc, sample);
mrtt = clib_max ((u32) (sample * THZ), 1);
/* Allow measuring of a new RTT */
tc->rtt_ts = 0;
* seq_lt (tc->snd_una, ack). This is a condition for calling update_rtt */
else if (tcp_opts_tstamp (&tc->rcv_opts) && tc->rcv_opts.tsecr)
{
- u32 now = tcp_tstamp (tc);
- mrtt = clib_max (now - tc->rcv_opts.tsecr, 1);
+ mrtt = clib_max (tcp_tstamp (tc) - tc->rcv_opts.tsecr, 1);
+ mrtt *= TCP_TSTP_TO_HZ;
}
estimate_rtt:
}
else
{
- mrtt = tcp_time_now_w_thread (thread_index) - tc->rcv_opts.tsecr;
- mrtt = clib_max (mrtt, 1);
+ mrtt = tcp_tstamp (tc) - tc->rcv_opts.tsecr;
+ mrtt = clib_max (mrtt, 1) * TCP_TSTP_TO_HZ;
/* Due to retransmits we don't know the initial mrtt */
if (tc->rto_boff && mrtt > 1 * THZ)
mrtt = 1 * THZ;
}
if (mrtt > 0 && mrtt < TCP_RTT_MAX)
- tcp_estimate_rtt (tc, mrtt);
+ {
+ /* First measurement as per RFC 6298 */
+ tc->srtt = mrtt;
+ tc->rttvar = mrtt >> 1;
+ }
tcp_update_rto (tc);
}
if (tc->cfg_flags & TCP_CFG_F_RATE_SAMPLE)
tcp_bt_sample_delivery_rate (tc, &rs);
- if (tc->bytes_acked)
+ if (tc->bytes_acked + tc->sack_sb.last_sacked_bytes)
{
- tcp_program_dequeue (wrk, tc);
tcp_update_rtt (tc, &rs, vnet_buffer (b)->tcp.ack_number);
+ if (tc->bytes_acked)
+ tcp_program_dequeue (wrk, tc);
}
TCP_EVT (TCP_EVT_ACK_RCVD, tc);
return TCP_ERROR_ENQUEUED_OOO;
}
-/**
- * Check if ACK could be delayed. If ack can be delayed, it should return
- * true for a full frame. If we're always acking return 0.
- */
-always_inline int
-tcp_can_delack (tcp_connection_t * tc)
-{
- /* Send ack if ... */
- if (TCP_ALWAYS_ACK
- /* just sent a rcv wnd 0
- || (tc->flags & TCP_CONN_SENT_RCV_WND0) != 0 */
- /* constrained to send ack */
- || (tc->flags & TCP_CONN_SNDACK) != 0
- /* we're almost out of tx wnd */
- || tcp_available_cc_snd_space (tc) < 4 * tc->snd_mss)
- return 0;
-
- return 1;
-}
-
static int
tcp_buffer_discard_bytes (vlib_buffer_t * b, u32 n_bytes_to_drop)
{
/* In order data, enqueue. Fifo figures out by itself if any out-of-order
* segments can be enqueued after fifo tail offset changes. */
error = tcp_session_enqueue_data (tc, b, n_data_bytes);
- if (tcp_can_delack (tc))
- {
- if (!tcp_timer_is_active (tc, TCP_TIMER_DELACK))
- tcp_timer_set (&wrk->timer_wheel, tc, TCP_TIMER_DELACK,
- tcp_cfg.delack_time);
- goto done;
- }
-
tcp_program_ack (tc);
done:
new_tc0->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID;
new_tc0->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
- /* If this is not the owning thread, wait for syn retransmit to
- * expire and cleanup then */
- if (tcp_half_open_connection_cleanup (tc0))
- tc0->flags |= TCP_CONN_HALF_OPEN_DONE;
-
if (tcp_opts_tstamp (&new_tc0->rcv_opts))
{
new_tc0->tsval_recent = new_tc0->rcv_opts.tsval;
tcp_send_reset_w_pkt (new_tc0, b0, my_thread_index, is_ip4);
tcp_connection_cleanup (new_tc0);
error0 = TCP_ERROR_CREATE_SESSION_FAIL;
- goto drop;
+ goto cleanup_ho;
}
new_tc0->tx_fifo_size =
tcp_send_reset_w_pkt (tc0, b0, my_thread_index, is_ip4);
TCP_EVT (TCP_EVT_RST_SENT, tc0);
error0 = TCP_ERROR_CREATE_SESSION_FAIL;
- goto drop;
+ goto cleanup_ho;
}
new_tc0->tx_fifo_size =
tcp_init_snd_vars (new_tc0);
tcp_send_synack (new_tc0);
error0 = TCP_ERROR_SYNS_RCVD;
- goto drop;
+ goto cleanup_ho;
}
if (!(new_tc0->cfg_flags & TCP_CFG_F_NO_TSO))
tcp_send_ack (new_tc0);
}
+ cleanup_ho:
+
+ /* If this is not the owning thread, wait for syn retransmit to
+ * expire and cleanup then */
+ if (tcp_half_open_connection_cleanup (tc0))
+ tc0->flags |= TCP_CONN_HALF_OPEN_DONE;
+
drop:
tcp_inc_counter (syn_sent, error0, 1);
tcp_connection_init_vars (child);
child->rto = TCP_RTO_MIN;
+ /*
+ * This initializes elog track, must be done before synack.
+ * We also do it before possible tcp_connection_cleanup() as it
+ * generates TCP_EVT_DELETE event.
+ */
+ TCP_EVT (TCP_EVT_SYN_RCVD, child, 1);
+
if (session_stream_accept (&child->connection, lc->c_s_index,
lc->c_thread_index, 0 /* notify */ ))
{
tcp_send_synack (child);
- TCP_EVT (TCP_EVT_SYN_RCVD, child, 1);
-
done:
if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
_(FIN_WAIT_2, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(FIN_WAIT_2, TCP_FLAG_RST | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
TCP_ERROR_NONE);
+ _(FIN_WAIT_2, TCP_FLAG_SYN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(CLOSE_WAIT, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(CLOSE_WAIT, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
TCP_ERROR_NONE);
_(CLOSE_WAIT, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(CLOSE_WAIT, TCP_FLAG_RST | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
TCP_ERROR_NONE);
+ _(CLOSE_WAIT, TCP_FLAG_SYN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(LAST_ACK, 0, TCP_INPUT_NEXT_DROP, TCP_ERROR_SEGMENT_INVALID);
_(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);
Code Review / vpp.git / blobdiff