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authorFlorin Coras <fcoras@cisco.com>2017-05-24 18:03:56 -0700
committerDave Barach <openvpp@barachs.net>2017-06-09 16:47:19 +0000
commit93992a9048cb6e5dcd22de5091e72de778122627 (patch)
treef295bb870ad1614d9327828dd036fb03f60e455e /src/vnet/tcp/tcp.h
parent583dc8d3e23a780c85ebe48ea59f0338aad4df17 (diff)
Implement sack based tcp loss recovery (RFC 6675)
- refactor existing congestion control code (RFC 6582/5681). Handling of ack feedback now consists of: ack parsing, cc event detection, event handling, congestion control update - extend sack scoreboard to support sack based retransmissions - basic implementation of Eifel detection algorithm (RFC 3522) for detecting spurious retransmissions - actually initialize the per-thread frame freelist hash tables - increase worker stack size to 2mb - fix session queue node out-of-buffer handling - ensure that the local buffer cache vec_len matches reality - avoid 2x spurious event requeues when short of buffers - count out-of-buffer events - make the builtin server thread-safe - fix bihash template threading issue: need to paint -1 across uninitialized working_copy_length vector elements (via rebase from master) Change-Id: I646cb9f1add9a67d08f4a87badbcb117980ebfc4 Signed-off-by: Florin Coras <fcoras@cisco.com> Signed-off-by: Dave Barach <dbarach@cisco.com>
Diffstat (limited to 'src/vnet/tcp/tcp.h')
-rw-r--r--src/vnet/tcp/tcp.h112
1 files changed, 94 insertions, 18 deletions
diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index c3ebe22bde9..071f1ab185f 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -34,6 +34,7 @@
#define TCP_MAX_RX_FIFO_SIZE 2 << 20
#define TCP_IW_N_SEGMENTS 10
#define TCP_ALWAYS_ACK 0 /**< If on, we always ack */
+#define TCP_USE_SACKS 1 /**< Disable only for testing */
/** TCP FSM state definitions as per RFC793. */
#define foreach_tcp_fsm_state \
@@ -94,7 +95,7 @@ extern timer_expiration_handler tcp_timer_retransmit_syn_handler;
#define TCP_DELACK_TIME 1 /* 0.1s */
#define TCP_ESTABLISH_TIME 750 /* 75s */
#define TCP_2MSL_TIME 300 /* 30s */
-#define TCP_CLOSEWAIT_TIME 1 /* 0.1s */
+#define TCP_CLOSEWAIT_TIME 20 /* 0.1s */
#define TCP_CLEANUP_TIME 5 /* 0.5s Time to wait before cleanup */
#define TCP_TIMER_PERSIST_MIN 2 /* 0.2s */
@@ -157,6 +158,7 @@ typedef struct _sack_scoreboard_hole
u32 prev; /**< Index for previous entry in linked list */
u32 start; /**< Start sequence number */
u32 end; /**< End sequence number */
+ u8 is_lost; /**< Mark hole as lost */
} sack_scoreboard_hole_t;
typedef struct _sack_scoreboard
@@ -166,8 +168,13 @@ typedef struct _sack_scoreboard
u32 tail; /**< Index of last entry */
u32 sacked_bytes; /**< Number of bytes sacked in sb */
u32 last_sacked_bytes; /**< Number of bytes last sacked */
+ u32 last_bytes_delivered; /**< Number of sack bytes delivered */
u32 snd_una_adv; /**< Bytes to add to snd_una */
- u32 max_byte_sacked; /**< Highest byte acked */
+ u32 high_sacked; /**< Highest byte sacked (fack) */
+ u32 high_rxt; /**< Highest retransmitted sequence */
+ u32 rescue_rxt; /**< Rescue sequence number */
+ u32 lost_bytes; /**< Bytes lost as per RFC6675 */
+ u32 cur_rxt_hole; /**< Retransmitting from this hole */
} sack_scoreboard_t;
typedef enum _tcp_cc_algorithm_type
@@ -211,7 +218,7 @@ typedef struct _tcp_connection
u32 irs; /**< initial remote sequence */
/* Options */
- tcp_options_t opt; /**< TCP connection options parsed */
+ tcp_options_t rcv_opts; /**< Rx options for connection */
tcp_options_t snd_opts; /**< Tx options for connection */
u8 snd_opts_len; /**< Tx options len */
u8 rcv_wscale; /**< Window scale to advertise to peer */
@@ -229,8 +236,10 @@ typedef struct _tcp_connection
u32 cwnd; /**< Congestion window */
u32 ssthresh; /**< Slow-start threshold */
u32 prev_ssthresh; /**< ssthresh before congestion */
+ u32 prev_cwnd; /**< ssthresh before congestion */
u32 bytes_acked; /**< Bytes acknowledged by current segment */
- u32 rtx_bytes; /**< Retransmitted bytes */
+ u32 snd_rxt_bytes; /**< Retransmitted bytes */
+ u32 snd_rxt_ts; /**< Timestamp when first packet is retransmitted */
u32 tsecr_last_ack; /**< Timestamp echoed to us in last healthy ACK */
u32 snd_congestion; /**< snd_una_max when congestion is detected */
tcp_cc_algorithm_t *cc_algo; /**< Congestion control algorithm */
@@ -411,6 +420,7 @@ void tcp_send_syn (tcp_connection_t * tc);
void tcp_send_fin (tcp_connection_t * tc);
void tcp_init_mss (tcp_connection_t * tc);
void tcp_update_snd_mss (tcp_connection_t * tc);
+void tcp_update_rto (tcp_connection_t * tc);
always_inline u32
tcp_end_seq (tcp_header_t * th, u32 len)
@@ -428,17 +438,39 @@ tcp_end_seq (tcp_header_t * th, u32 len)
#define timestamp_lt(_t1, _t2) ((i32)((_t1)-(_t2)) < 0)
#define timestamp_leq(_t1, _t2) ((i32)((_t1)-(_t2)) <= 0)
+/**
+ * Our estimate of the number of bytes that have left the network
+ */
+always_inline u32
+tcp_bytes_out (const tcp_connection_t * tc)
+{
+ if (tcp_opts_sack_permitted (&tc->rcv_opts))
+ return tc->sack_sb.sacked_bytes + tc->sack_sb.lost_bytes;
+ else
+ return tc->rcv_dupacks * tc->snd_mss;
+}
+
+/**
+ * Our estimate of the number of bytes in flight (pipe size)
+ */
always_inline u32
tcp_flight_size (const tcp_connection_t * tc)
{
int flight_size;
- flight_size = (int) ((tc->snd_una_max - tc->snd_una) + tc->rtx_bytes)
- - (tc->rcv_dupacks * tc->snd_mss) /* - tc->sack_sb.sacked_bytes */ ;
+ flight_size = (int) (tc->snd_una_max - tc->snd_una) - tcp_bytes_out (tc)
+ + tc->snd_rxt_bytes;
- /* Happens if we don't clear sacked bytes */
if (flight_size < 0)
- return 0;
+ {
+ if (0)
+ clib_warning
+ ("Negative: %u %u %u dupacks %u sacked bytes %u flags %d",
+ tc->snd_una_max - tc->snd_una, tcp_bytes_out (tc),
+ tc->snd_rxt_bytes, tc->rcv_dupacks, tc->sack_sb.sacked_bytes,
+ tc->rcv_opts.flags);
+ return 0;
+ }
return flight_size;
}
@@ -481,14 +513,17 @@ tcp_available_snd_space (const tcp_connection_t * tc)
return available_wnd - flight_size;
}
-u32 tcp_rcv_wnd_available (tcp_connection_t * tc);
+i32 tcp_rcv_wnd_available (tcp_connection_t * tc);
u32 tcp_snd_space (tcp_connection_t * tc);
void tcp_update_rcv_wnd (tcp_connection_t * tc);
void tcp_retransmit_first_unacked (tcp_connection_t * tc);
+void tcp_fast_retransmit_no_sack (tcp_connection_t * tc);
+void tcp_fast_retransmit_sack (tcp_connection_t * tc);
void tcp_fast_retransmit (tcp_connection_t * tc);
-void tcp_cc_congestion (tcp_connection_t * tc);
-void tcp_cc_recover (tcp_connection_t * tc);
+void tcp_cc_init_congestion (tcp_connection_t * tc);
+int tcp_cc_recover (tcp_connection_t * tc);
+void tcp_cc_fastrecovery_exit (tcp_connection_t * tc);
/* Made public for unit testing only */
void tcp_update_sack_list (tcp_connection_t * tc, u32 start, u32 end);
@@ -563,16 +598,16 @@ tcp_retransmit_timer_set (tcp_connection_t * tc)
}
always_inline void
-tcp_retransmit_timer_update (tcp_connection_t * tc)
+tcp_retransmit_timer_reset (tcp_connection_t * tc)
{
- tcp_timer_update (tc, TCP_TIMER_RETRANSMIT,
- clib_max (tc->rto * TCP_TO_TIMER_TICK, 1));
+ tcp_timer_reset (tc, TCP_TIMER_RETRANSMIT);
}
always_inline void
-tcp_retransmit_timer_reset (tcp_connection_t * tc)
+tcp_retransmit_timer_force_update (tcp_connection_t * tc)
{
- tcp_timer_reset (tc, TCP_TIMER_RETRANSMIT);
+ tcp_timer_update (tc, TCP_TIMER_RETRANSMIT,
+ clib_max (tc->rto * TCP_TO_TIMER_TICK, 1));
}
always_inline void
@@ -598,15 +633,43 @@ tcp_persist_timer_reset (tcp_connection_t * tc)
tcp_timer_reset (tc, TCP_TIMER_PERSIST);
}
+always_inline void
+tcp_retransmit_timer_update (tcp_connection_t * tc)
+{
+ if (tc->snd_una == tc->snd_una_max)
+ {
+ tcp_retransmit_timer_reset (tc);
+ if (tc->snd_wnd < tc->snd_mss)
+ tcp_persist_timer_set (tc);
+ }
+ else
+ tcp_timer_update (tc, TCP_TIMER_RETRANSMIT,
+ clib_max (tc->rto * TCP_TO_TIMER_TICK, 1));
+}
+
always_inline u8
tcp_timer_is_active (tcp_connection_t * tc, tcp_timers_e timer)
{
return tc->timers[timer] != TCP_TIMER_HANDLE_INVALID;
}
+#define tcp_validate_txf_size(_tc, _a) \
+ ASSERT(_tc->state != TCP_STATE_ESTABLISHED \
+ || stream_session_tx_fifo_max_dequeue (&_tc->connection) >= _a)
+
void
scoreboard_remove_hole (sack_scoreboard_t * sb,
sack_scoreboard_hole_t * hole);
+void scoreboard_update_lost (tcp_connection_t * tc, sack_scoreboard_t * sb);
+sack_scoreboard_hole_t *scoreboard_insert_hole (sack_scoreboard_t * sb,
+ u32 prev_index, u32 start,
+ u32 end);
+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);
+void scoreboard_init_high_rxt (sack_scoreboard_t * sb);
always_inline sack_scoreboard_hole_t *
scoreboard_get_hole (sack_scoreboard_t * sb, u32 index)
@@ -625,6 +688,14 @@ scoreboard_next_hole (sack_scoreboard_t * sb, sack_scoreboard_hole_t * hole)
}
always_inline sack_scoreboard_hole_t *
+scoreboard_prev_hole (sack_scoreboard_t * sb, sack_scoreboard_hole_t * hole)
+{
+ if (hole->prev != TCP_INVALID_SACK_HOLE_INDEX)
+ return pool_elt_at_index (sb->holes, hole->prev);
+ return 0;
+}
+
+always_inline sack_scoreboard_hole_t *
scoreboard_first_hole (sack_scoreboard_t * sb)
{
if (sb->head != TCP_INVALID_SACK_HOLE_INDEX)
@@ -643,15 +714,19 @@ scoreboard_last_hole (sack_scoreboard_t * sb)
always_inline void
scoreboard_clear (sack_scoreboard_t * sb)
{
- sack_scoreboard_hole_t *hole = scoreboard_first_hole (sb);
+ sack_scoreboard_hole_t *hole;
while ((hole = scoreboard_first_hole (sb)))
{
scoreboard_remove_hole (sb, hole);
}
sb->sacked_bytes = 0;
sb->last_sacked_bytes = 0;
+ sb->last_bytes_delivered = 0;
sb->snd_una_adv = 0;
- sb->max_byte_sacked = 0;
+ sb->high_sacked = 0;
+ sb->high_rxt = 0;
+ sb->lost_bytes = 0;
+ sb->cur_rxt_hole = TCP_INVALID_SACK_HOLE_INDEX;
}
always_inline u32
@@ -671,6 +746,7 @@ 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;
}
void tcp_rcv_sacks (tcp_connection_t * tc, u32 ack);