}
}
+/**
+ * RFC1323: Check against wrapped sequence numbers (PAWS). If we have
+ * timestamp to echo and it's less than tsval_recent, drop segment
+ * but still send an ACK in order to retain TCP's mechanism for detecting
+ * and recovering from half-open connections
+ *
+ * Or at least that's what the theory says. It seems that this might not work
+ * very well with packet reordering and fast retransmit. XXX
+ */
always_inline int
tcp_segment_check_paws (tcp_connection_t * tc)
{
&& timestamp_lt (tc->opt.tsval, tc->tsval_recent);
}
+/**
+ * Update tsval recent
+ */
+always_inline void
+tcp_update_timestamp (tcp_connection_t * tc, u32 seq, u32 seq_end)
+{
+ /*
+ * RFC1323: If Last.ACK.sent falls within the range of sequence numbers
+ * of an incoming segment:
+ * SEG.SEQ <= Last.ACK.sent < SEG.SEQ + SEG.LEN
+ * 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
+ && seq_leq (seq, tc->rcv_las) && seq_leq (tc->rcv_las, seq_end))
+ {
+ tc->tsval_recent = tc->opt.tsval;
+ tc->tsval_recent_age = tcp_time_now ();
+ }
+}
+
/**
* Validate incoming segment as per RFC793 p. 69 and RFC1323 p. 19
*
tcp_segment_validate (vlib_main_t * vm, tcp_connection_t * tc0,
vlib_buffer_t * b0, tcp_header_t * th0, u32 * next0)
{
- u8 paws_failed;
-
if (PREDICT_FALSE (!tcp_ack (th0) && !tcp_rst (th0) && !tcp_syn (th0)))
return -1;
tcp_options_parse (th0, &tc0->opt);
- /* RFC1323: Check against wrapped sequence numbers (PAWS). If we have
- * timestamp to echo and it's less than tsval_recent, drop segment
- * but still send an ACK in order to retain TCP's mechanism for detecting
- * and recovering from half-open connections */
- paws_failed = tcp_segment_check_paws (tc0);
- if (paws_failed)
+ if (tcp_segment_check_paws (tc0))
{
clib_warning ("paws failed");
+ TCP_EVT_DBG (TCP_EVT_PAWS_FAIL, tc0, vnet_buffer (b0)->tcp.seq_number,
+ vnet_buffer (b0)->tcp.seq_end);
/* If it just so happens that a segment updates tsval_recent for a
* segment over 24 days old, invalidate tsval_recent. */
{
/* Age isn't reset until we get a valid tsval (bsd inspired) */
tc0->tsval_recent = 0;
+ clib_warning ("paws failed - really old segment. REALLY?");
}
else
{
return -1;
}
- /* If PAWS passed and segment in window, save timestamp */
- if (!paws_failed)
- {
- tc0->tsval_recent = tc0->opt.tsval;
- tc0->tsval_recent_age = tcp_time_now ();
- }
+ /* If segment in window, save timestamp */
+ tcp_update_timestamp (tc0, vnet_buffer (b0)->tcp.seq_number,
+ vnet_buffer (b0)->tcp.seq_end);
return 0;
}
tcp_update_rtt (tcp_connection_t * tc, u32 ack)
{
u32 mrtt = 0;
+ u8 rtx_acked;
+
+ /* Determine if only rtx bytes are acked. TODO 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
* RTT because they're ambiguous. */
- if (tc->rtt_seq && seq_gt (ack, tc->rtt_seq) && !tc->rto_boff)
+ if (tc->rtt_ts && seq_geq (ack, tc->rtt_seq) && !rtx_acked)
{
mrtt = tcp_time_now () - tc->rtt_ts;
}
-
/* As per RFC7323 TSecr can be used for RTTM only if the segment advances
* 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
mrtt = tcp_time_now () - tc->opt.tsecr;
}
+ /* Allow measuring of a new RTT */
+ tc->rtt_ts = 0;
+
+ /* If ACK moves left side of the wnd make sure boff is 0, even if mrtt is
+ * not valid */
+ if (tc->bytes_acked)
+ tc->rto_boff = 0;
+
/* Ignore dubious measurements */
if (mrtt == 0 || mrtt > TCP_RTT_MAX)
return 0;
tcp_estimate_rtt (tc, mrtt);
-
tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX);
- /* Allow measuring of RTT and make sure boff is 0 */
- tc->rtt_seq = 0;
- tc->rto_boff = 0;
-
- return 1;
+ return 0;
}
/**
{
u8 partial_ack;
- if (tcp_in_cong_recovery (tc))
+ if (tcp_in_fastrecovery (tc))
{
partial_ack = seq_lt (tc->snd_una, tc->snd_congestion);
if (!partial_ack)
/* Clear retransmitted bytes. XXX should we clear all? */
tc->rtx_bytes = 0;
+
tc->cc_algo->rcv_cong_ack (tc, TCP_CC_PARTIALACK);
/* In case snd_nxt is still in the past and output tries to
tc->cc_algo->rcv_ack (tc);
tc->tsecr_last_ack = tc->opt.tsecr;
tc->rcv_dupacks = 0;
+ if (tcp_in_recovery (tc))
+ {
+ tc->rtx_bytes -= clib_min (tc->bytes_acked, tc->rtx_bytes);
+ tc->rto = clib_min (tc->srtt + (tc->rttvar << 2), TCP_RTO_MAX);
+ if (seq_geq (tc->snd_una, tc->snd_congestion))
+ tcp_recovery_off (tc);
+ }
}
}
TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc);
tcp_cc_rcv_dupack (tc, vnet_buffer (b)->tcp.ack_number);
}
- return -1;
+ /* Don't drop yet */
+ return 0;
}
if (tcp_opts_sack_permitted (&tc->opt))
tcp_cc_rcv_ack (tc, b);
/* If everything has been acked, stop retransmit timer
- * otherwise update */
+ * otherwise update. */
if (tc->snd_una == tc->snd_una_max)
tcp_retransmit_timer_reset (tc);
else
{
vec_add1 (new_list, tc->snd_sacks[i]);
}
- else
- {
- clib_warning ("dropped sack blocks");
- }
}
ASSERT (vec_len (new_list) <= TCP_MAX_SACK_BLOCKS);
return TCP_ERROR_PURE_ACK;
}
- written = stream_session_enqueue_data (&tc->connection,
- vlib_buffer_get_current (b),
- data_len, 1 /* queue event */ );
+ written = stream_session_enqueue_data (&tc->connection, b, 0,
+ 1 /* queue event */ , 1);
TCP_EVT_DBG (TCP_EVT_INPUT, tc, 0, data_len, written);
u16 data_len)
{
stream_session_t *s0;
- u32 offset;
int rv;
/* Pure ACK. Do nothing */
return TCP_ERROR_PURE_ACK;
}
- s0 = stream_session_get (tc->c_s_index, tc->c_thread_index);
- offset = vnet_buffer (b)->tcp.seq_number - tc->irs;
-
- clib_warning ("ooo: offset %d len %d", offset, data_len);
-
- rv = svm_fifo_enqueue_with_offset (s0->server_rx_fifo, offset, data_len,
- vlib_buffer_get_current (b));
+ /* Enqueue out-of-order data with absolute offset */
+ rv = stream_session_enqueue_data (&tc->connection, b,
+ vnet_buffer (b)->tcp.seq_number,
+ 0 /* queue event */ , 0);
/* Nothing written */
if (rv)
ooo_segment_t *newest;
u32 start, end;
+ s0 = stream_session_get (tc->c_s_index, tc->c_thread_index);
+
/* Get the newest segment from the fifo */
newest = svm_fifo_newest_ooo_segment (s0->server_rx_fifo);
start = ooo_segment_offset (s0->server_rx_fifo, newest);
/* Notify app that we have connection */
stream_session_connect_notify (&new_tc0->connection, sst, 0);
+ stream_session_init_fifos_pointers (&new_tc0->connection,
+ new_tc0->irs + 1,
+ new_tc0->iss + 1);
/* Make sure after data segment processing ACK is sent */
new_tc0->flags |= TCP_CONN_SNDACK;
}
/* Notify app that we have connection */
stream_session_connect_notify (&new_tc0->connection, sst, 0);
-
+ stream_session_init_fifos_pointers (&new_tc0->connection,
+ new_tc0->irs + 1,
+ new_tc0->iss + 1);
tcp_make_synack (new_tc0, b0);
next0 = tcp_next_output (is_ip4);
tcp_send_reset (b0, is_ip4);
goto drop;
}
+
+ /* Update rtt and rto */
+ tc0->bytes_acked = 1;
+ tcp_update_rtt (tc0, vnet_buffer (b0)->tcp.ack_number);
+
/* Switch state to ESTABLISHED */
tc0->state = TCP_STATE_ESTABLISHED;
tcp_make_synack (child0, b0);
next0 = tcp_next_output (is_ip4);
+ /* Init fifo pointers after we have iss */
+ stream_session_init_fifos_pointers (&child0->connection,
+ child0->irs + 1,
+ child0->iss + 1);
drop:
if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
{
_(LISTEN, TCP_FLAG_SYN, TCP_INPUT_NEXT_LISTEN, TCP_ERROR_NONE);
/* ACK for for a SYN-ACK -> tcp-rcv-process. */
_(SYN_RCVD, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(SYN_RCVD, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
/* SYN-ACK for a SYN */
_(SYN_SENT, TCP_FLAG_SYN | TCP_FLAG_ACK, TCP_INPUT_NEXT_SYN_SENT,
TCP_ERROR_NONE);
_(FIN_WAIT_1, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
/* FIN confirming that the peer (app) has closed */
_(FIN_WAIT_2, TCP_FLAG_FIN, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(FIN_WAIT_2, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
_(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);
+ _(CLOSED, TCP_FLAG_ACK, TCP_INPUT_NEXT_DROP, TCP_ERROR_CONNECTION_CLOSED);
#undef _
}
Code Review / vpp.git / blobdiff