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diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
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+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _vnet_tcp_h_
+#define _vnet_tcp_h_
+
+#include <vnet/vnet.h>
+#include <vnet/ip/ip.h>
+#include <vnet/tcp/tcp_packet.h>
+#include <vnet/tcp/tcp_timer.h>
+#include <vnet/session/transport.h>
+#include <vnet/session/session.h>
+
+#define TCP_TICK 10e-3 /**< TCP tick period (s) */
+#define THZ 1/TCP_TICK /**< TCP tick frequency */
+#define TCP_TSTAMP_RESOLUTION TCP_TICK /**< Time stamp resolution */
+#define TCP_PAWS_IDLE 24 * 24 * 60 * 60 * THZ /**< 24 days */
+#define TCP_MAX_OPTION_SPACE 40
+
+#define TCP_DUPACK_THRESHOLD 3
+#define TCP_DEFAULT_RX_FIFO_SIZE 64 << 10
+
+/** TCP FSM state definitions as per RFC793. */
+#define foreach_tcp_fsm_state \
+ _(CLOSED, "CLOSED") \
+ _(LISTEN, "LISTEN") \
+ _(SYN_SENT, "SYN_SENT") \
+ _(SYN_RCVD, "SYN_RCVD") \
+ _(ESTABLISHED, "ESTABLISHED") \
+ _(CLOSE_WAIT, "CLOSE_WAIT") \
+ _(FIN_WAIT_1, "FIN_WAIT_1") \
+ _(LAST_ACK, "LAST_ACK") \
+ _(CLOSING, "CLOSING") \
+ _(FIN_WAIT_2, "FIN_WAIT_2") \
+ _(TIME_WAIT, "TIME_WAIT")
+
+typedef enum _tcp_state
+{
+#define _(sym, str) TCP_STATE_##sym,
+ foreach_tcp_fsm_state
+#undef _
+ TCP_N_STATES
+} tcp_state_t;
+
+format_function_t format_tcp_state;
+
+/** TCP timers */
+#define foreach_tcp_timer \
+ _(RETRANSMIT, "RETRANSMIT") \
+ _(DELACK, "DELAYED ACK") \
+ _(PERSIST, "PERSIST") \
+ _(KEEP, "KEEP") \
+ _(2MSL, "2MSL") \
+ _(RETRANSMIT_SYN, "RETRANSMIT_SYN") \
+ _(ESTABLISH, "ESTABLISH")
+
+typedef enum _tcp_timers
+{
+#define _(sym, str) TCP_TIMER_##sym,
+ foreach_tcp_timer
+#undef _
+ TCP_N_TIMERS
+} tcp_timers_e;
+
+typedef void (timer_expiration_handler) (u32 index);
+
+extern timer_expiration_handler tcp_timer_delack_handler;
+extern timer_expiration_handler tcp_timer_retransmit_handler;
+extern timer_expiration_handler tcp_timer_retransmit_syn_handler;
+
+#define TCP_TIMER_HANDLE_INVALID ((u32) ~0)
+
+/* Timer delays as multiples of 100ms */
+#define TCP_TO_TIMER_TICK TCP_TICK*10 /* Period for converting from TCP
+ * ticks to timer units */
+#define TCP_DELACK_TIME 1 /* 0.1s */
+#define TCP_ESTABLISH_TIME 750 /* 75s */
+#define TCP_2MSL_TIME 300 /* 30s */
+
+#define TCP_RTO_MAX 60 * THZ /* Min max RTO (60s) as per RFC6298 */
+#define TCP_RTT_MAX 30 * THZ /* 30s (probably too much) */
+#define TCP_RTO_SYN_RETRIES 3 /* SYN retries without doubling RTO */
+#define TCP_RTO_INIT 1 * THZ /* Initial retransmit timer */
+
+void tcp_update_time (f64 now, u32 thread_index);
+
+/** TCP connection flags */
+#define foreach_tcp_connection_flag \
+ _(DELACK, "Delay ACK") \
+ _(SNDACK, "Send ACK") \
+ _(BURSTACK, "Burst ACK set") \
+ _(SENT_RCV_WND0, "Sent 0 receive window") \
+ _(RECOVERY, "Recovery on") \
+ _(FAST_RECOVERY, "Fast Recovery on")
+
+typedef enum _tcp_connection_flag_bits
+{
+#define _(sym, str) TCP_CONN_##sym##_BIT,
+ foreach_tcp_connection_flag
+#undef _
+ TCP_CONN_N_FLAG_BITS
+} tcp_connection_flag_bits_e;
+
+typedef enum _tcp_connection_flag
+{
+#define _(sym, str) TCP_CONN_##sym = 1 << TCP_CONN_##sym##_BIT,
+ foreach_tcp_connection_flag
+#undef _
+ TCP_CONN_N_FLAGS
+} tcp_connection_flags_e;
+
+/** TCP buffer flags */
+#define foreach_tcp_buf_flag \
+ _ (ACK) /**< Sending ACK. */ \
+ _ (DUPACK) /**< Sending DUPACK. */ \
+
+enum
+{
+#define _(f) TCP_BUF_BIT_##f,
+ foreach_tcp_buf_flag
+#undef _
+ TCP_N_BUF_BITS,
+};
+
+enum
+{
+#define _(f) TCP_BUF_FLAG_##f = 1 << TCP_BUF_BIT_##f,
+ foreach_tcp_buf_flag
+#undef _
+};
+
+#define TCP_MAX_SACK_BLOCKS 5 /**< Max number of SACK blocks stored */
+#define TCP_INVALID_SACK_HOLE_INDEX ((u32)~0)
+
+typedef struct _sack_scoreboard_hole
+{
+ u32 next; /**< Index for next entry in linked list */
+ u32 prev; /**< Index for previous entry in linked list */
+ u32 start; /**< Start sequence number */
+ u32 end; /**< End sequence number */
+} sack_scoreboard_hole_t;
+
+typedef struct _sack_scoreboard
+{
+ sack_scoreboard_hole_t *holes; /**< Pool of holes */
+ u32 head; /**< Index to first entry */
+ u32 sacked_bytes; /**< Number of bytes sacked in sb */
+} sack_scoreboard_t;
+
+typedef enum _tcp_cc_algorithm_type
+{
+ TCP_CC_NEWRENO,
+} tcp_cc_algorithm_type_e;
+
+typedef struct _tcp_cc_algorithm tcp_cc_algorithm_t;
+
+typedef enum _tcp_cc_ack_t
+{
+ TCP_CC_ACK,
+ TCP_CC_DUPACK,
+ TCP_CC_PARTIALACK
+} tcp_cc_ack_t;
+
+typedef struct _tcp_connection
+{
+ transport_connection_t connection; /**< Common transport data. First! */
+
+ u8 state; /**< TCP state as per tcp_state_t */
+ u16 flags; /**< Connection flags (see tcp_conn_flags_e) */
+ u32 timers[TCP_N_TIMERS]; /**< Timer handles into timer wheel */
+
+ /* TODO RFC4898 */
+
+ /** Send sequence variables RFC793 */
+ u32 snd_una; /**< oldest unacknowledged sequence number */
+ u32 snd_una_max; /**< newest unacknowledged sequence number + 1*/
+ u32 snd_wnd; /**< send window */
+ u32 snd_wl1; /**< seq number used for last snd.wnd update */
+ u32 snd_wl2; /**< ack number used for last snd.wnd update */
+ u32 snd_nxt; /**< next seq number to be sent */
+
+ /** Receive sequence variables RFC793 */
+ u32 rcv_nxt; /**< next sequence number expected */
+ u32 rcv_wnd; /**< receive window we expect */
+
+ u32 rcv_las; /**< rcv_nxt at last ack sent/rcv_wnd update */
+ u32 iss; /**< initial sent sequence */
+ u32 irs; /**< initial remote sequence */
+
+ /* Options */
+ tcp_options_t opt; /**< TCP connection options parsed */
+ u8 rcv_wscale; /**< Window scale to advertise to peer */
+ u8 snd_wscale; /**< Window scale to use when sending */
+ u32 tsval_recent; /**< Last timestamp received */
+ u32 tsval_recent_age; /**< When last updated tstamp_recent*/
+
+ sack_block_t *snd_sacks; /**< Vector of SACKs to send. XXX Fixed size? */
+ sack_scoreboard_t sack_sb; /**< SACK "scoreboard" that tracks holes */
+
+ u8 rcv_dupacks; /**< Number of DUPACKs received */
+ u8 snt_dupacks; /**< Number of DUPACKs sent in a burst */
+
+ /* Congestion control */
+ u32 cwnd; /**< Congestion window */
+ u32 ssthresh; /**< Slow-start threshold */
+ u32 prev_ssthresh; /**< ssthresh before congestion */
+ u32 bytes_acked; /**< Bytes acknowledged by current segment */
+ u32 rtx_bytes; /**< Retransmitted bytes */
+ u32 tsecr_last_ack; /**< Timestamp echoed to us in last health ACK */
+ tcp_cc_algorithm_t *cc_algo; /**< Congestion control algorithm */
+
+ /* RTT and RTO */
+ u32 rto; /**< Retransmission timeout */
+ u32 rto_boff; /**< Index for RTO backoff */
+ u32 srtt; /**< Smoothed RTT */
+ u32 rttvar; /**< Smoothed mean RTT difference. Approximates variance */
+ u32 rtt_ts; /**< Timestamp for tracked ACK */
+ u32 rtt_seq; /**< Sequence number for tracked ACK */
+
+ u16 snd_mss; /**< Send MSS */
+} tcp_connection_t;
+
+struct _tcp_cc_algorithm
+{
+ void (*rcv_ack) (tcp_connection_t * tc);
+ void (*rcv_cong_ack) (tcp_connection_t * tc, tcp_cc_ack_t ack);
+ void (*congestion) (tcp_connection_t * tc);
+ void (*recovered) (tcp_connection_t * tc);
+ void (*init) (tcp_connection_t * tc);
+};
+
+#define tcp_fastrecovery_on(tc) (tc)->flags |= TCP_CONN_FAST_RECOVERY
+#define tcp_fastrecovery_off(tc) (tc)->flags &= ~TCP_CONN_FAST_RECOVERY
+#define tcp_in_fastrecovery(tc) ((tc)->flags & TCP_CONN_FAST_RECOVERY)
+#define tcp_in_recovery(tc) ((tc)->flags & (TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))
+#define tcp_recovery_off(tc) ((tc)->flags &= ~(TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))
+#define tcp_in_slowstart(tc) (tc->cwnd < tc->ssthresh)
+
+typedef enum
+{
+ TCP_IP4,
+ TCP_IP6,
+ TCP_N_AF,
+} tcp_af_t;
+
+typedef enum _tcp_error
+{
+#define tcp_error(n,s) TCP_ERROR_##n,
+#include <vnet/tcp/tcp_error.def>
+#undef tcp_error
+ TCP_N_ERROR,
+} tcp_error_t;
+
+typedef struct _tcp_lookup_dispatch
+{
+ u8 next, error;
+} tcp_lookup_dispatch_t;
+
+typedef struct _tcp_main
+{
+ /* Per-worker thread tcp connection pools */
+ tcp_connection_t **connections;
+
+ /* Pool of listeners. */
+ tcp_connection_t *listener_pool;
+
+ /** Dispatch table by state and flags */
+ tcp_lookup_dispatch_t dispatch_table[TCP_N_STATES][64];
+
+ u8 log2_tstamp_clocks_per_tick;
+ f64 tstamp_ticks_per_clock;
+
+ /** per-worker tx buffer free lists */
+ u32 **tx_buffers;
+
+ /* Per worker-thread timer wheel for connections timers */
+ tw_timer_wheel_16t_2w_512sl_t *timer_wheels;
+
+ /* Convenience per worker-thread vector of connections to DELACK */
+ u32 **delack_connections;
+
+ /* Pool of half-open connections on which we've sent a SYN */
+ tcp_connection_t *half_open_connections;
+
+ /* Pool of local TCP endpoints */
+ transport_endpoint_t *local_endpoints;
+
+ /* Local endpoints lookup table */
+ transport_endpoint_table_t local_endpoints_table;
+
+ /* Congestion control algorithms registered */
+ tcp_cc_algorithm_t *cc_algos;
+
+ /* convenience */
+ vlib_main_t *vlib_main;
+ vnet_main_t *vnet_main;
+ ip4_main_t *ip4_main;
+ ip6_main_t *ip6_main;
+} tcp_main_t;
+
+extern tcp_main_t tcp_main;
+extern vlib_node_registration_t tcp4_input_node;
+extern vlib_node_registration_t tcp6_input_node;
+extern vlib_node_registration_t tcp4_output_node;
+extern vlib_node_registration_t tcp6_output_node;
+
+always_inline tcp_main_t *
+vnet_get_tcp_main ()
+{
+ return &tcp_main;
+}
+
+always_inline tcp_connection_t *
+tcp_connection_get (u32 conn_index, u32 thread_index)
+{
+ return pool_elt_at_index (tcp_main.connections[thread_index], conn_index);
+}
+
+always_inline tcp_connection_t *
+tcp_connection_get_if_valid (u32 conn_index, u32 thread_index)
+{
+ if (tcp_main.connections[thread_index] == 0)
+ return 0;
+ if (pool_is_free_index (tcp_main.connections[thread_index], conn_index))
+ return 0;
+ return pool_elt_at_index (tcp_main.connections[thread_index], conn_index);
+}
+
+void tcp_connection_close (tcp_connection_t * tc);
+void tcp_connection_cleanup (tcp_connection_t * tc);
+void tcp_connection_del (tcp_connection_t * tc);
+
+always_inline tcp_connection_t *
+tcp_listener_get (u32 tli)
+{
+ return pool_elt_at_index (tcp_main.listener_pool, tli);
+}
+
+always_inline tcp_connection_t *
+tcp_half_open_connection_get (u32 conn_index)
+{
+ return pool_elt_at_index (tcp_main.half_open_connections, conn_index);
+}
+
+void tcp_make_ack (tcp_connection_t * ts, vlib_buffer_t * b);
+void tcp_make_finack (tcp_connection_t * tc, vlib_buffer_t * b);
+void tcp_make_synack (tcp_connection_t * ts, vlib_buffer_t * b);
+void tcp_send_reset (vlib_buffer_t * pkt, u8 is_ip4);
+void tcp_send_syn (tcp_connection_t * tc);
+void tcp_send_fin (tcp_connection_t * tc);
+void tcp_set_snd_mss (tcp_connection_t * tc);
+
+always_inline u32
+tcp_end_seq (tcp_header_t * th, u32 len)
+{
+ return th->seq_number + tcp_is_syn (th) + tcp_is_fin (th) + len;
+}
+
+/* Modulo arithmetic for TCP sequence numbers */
+#define seq_lt(_s1, _s2) ((i32)((_s1)-(_s2)) < 0)
+#define seq_leq(_s1, _s2) ((i32)((_s1)-(_s2)) <= 0)
+#define seq_gt(_s1, _s2) ((i32)((_s1)-(_s2)) > 0)
+#define seq_geq(_s1, _s2) ((i32)((_s1)-(_s2)) >= 0)
+
+/* Modulo arithmetic for timestamps */
+#define timestamp_lt(_t1, _t2) ((i32)((_t1)-(_t2)) < 0)
+#define timestamp_leq(_t1, _t2) ((i32)((_t1)-(_t2)) <= 0)
+
+always_inline u32
+tcp_flight_size (const tcp_connection_t * tc)
+{
+ return tc->snd_una_max - tc->snd_una - tc->sack_sb.sacked_bytes
+ + tc->rtx_bytes;
+}
+
+/**
+ * Initial cwnd as per RFC5681
+ */
+always_inline u32
+tcp_initial_cwnd (const tcp_connection_t * tc)
+{
+ if (tc->snd_mss > 2190)
+ return 2 * tc->snd_mss;
+ else if (tc->snd_mss > 1095)
+ return 3 * tc->snd_mss;
+ else
+ return 4 * tc->snd_mss;
+}
+
+always_inline u32
+tcp_loss_wnd (const tcp_connection_t * tc)
+{
+ return tc->snd_mss;
+}
+
+always_inline u32
+tcp_available_wnd (const tcp_connection_t * tc)
+{
+ return clib_min (tc->cwnd, tc->snd_wnd);
+}
+
+always_inline u32
+tcp_available_snd_space (const tcp_connection_t * tc)
+{
+ u32 available_wnd = tcp_available_wnd (tc);
+ u32 flight_size = tcp_flight_size (tc);
+
+ if (available_wnd <= flight_size)
+ return 0;
+
+ return available_wnd - flight_size;
+}
+
+void tcp_retransmit_first_unacked (tcp_connection_t * tc);
+
+void tcp_fast_retransmit (tcp_connection_t * tc);
+
+always_inline u32
+tcp_time_now (void)
+{
+ return clib_cpu_time_now () * tcp_main.tstamp_ticks_per_clock;
+}
+
+u32 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b);
+
+u32
+tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b,
+ u32 max_bytes);
+
+void tcp_connection_timers_init (tcp_connection_t * tc);
+void tcp_connection_timers_reset (tcp_connection_t * tc);
+
+void tcp_connection_init_vars (tcp_connection_t * tc);
+
+always_inline void
+tcp_connection_force_ack (tcp_connection_t * tc, vlib_buffer_t * b)
+{
+ /* Reset flags, make sure ack is sent */
+ tc->flags = TCP_CONN_SNDACK;
+ vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK;
+}
+
+always_inline void
+tcp_timer_set (tcp_connection_t * tc, u8 timer_id, u32 interval)
+{
+ tc->timers[timer_id]
+ = tw_timer_start_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
+ tc->c_c_index, timer_id, interval);
+}
+
+always_inline void
+tcp_retransmit_timer_set (tcp_main_t * tm, tcp_connection_t * tc)
+{
+ /* XXX Switch to faster TW */
+ tcp_timer_set (tc, TCP_TIMER_RETRANSMIT,
+ clib_max (tc->rto * TCP_TO_TIMER_TICK, 1));
+}
+
+always_inline void
+tcp_timer_reset (tcp_connection_t * tc, u8 timer_id)
+{
+ if (tc->timers[timer_id] == TCP_TIMER_HANDLE_INVALID)
+ return;
+
+ tw_timer_stop_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
+ tc->timers[timer_id]);
+ tc->timers[timer_id] = TCP_TIMER_HANDLE_INVALID;
+}
+
+always_inline void
+tcp_timer_update (tcp_connection_t * tc, u8 timer_id, u32 interval)
+{
+ if (tc->timers[timer_id] != TCP_TIMER_HANDLE_INVALID)
+ tw_timer_stop_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
+ tc->timers[timer_id]);
+ tc->timers[timer_id] =
+ tw_timer_start_16t_2w_512sl (&tcp_main.timer_wheels[tc->c_thread_index],
+ tc->c_c_index, timer_id, interval);
+}
+
+always_inline u8
+tcp_timer_is_active (tcp_connection_t * tc, tcp_timers_e timer)
+{
+ return tc->timers[timer] != TCP_TIMER_HANDLE_INVALID;
+}
+
+void
+scoreboard_remove_hole (sack_scoreboard_t * sb,
+ sack_scoreboard_hole_t * hole);
+
+always_inline sack_scoreboard_hole_t *
+scoreboard_next_hole (sack_scoreboard_t * sb, sack_scoreboard_hole_t * hole)
+{
+ if (hole->next != TCP_INVALID_SACK_HOLE_INDEX)
+ return pool_elt_at_index (sb->holes, hole->next);
+ return 0;
+}
+
+always_inline sack_scoreboard_hole_t *
+scoreboard_first_hole (sack_scoreboard_t * sb)
+{
+ if (sb->head != TCP_INVALID_SACK_HOLE_INDEX)
+ return pool_elt_at_index (sb->holes, sb->head);
+ return 0;
+}
+
+always_inline void
+scoreboard_clear (sack_scoreboard_t * sb)
+{
+ sack_scoreboard_hole_t *hole = scoreboard_first_hole (sb);
+ while ((hole = scoreboard_first_hole (sb)))
+ {
+ scoreboard_remove_hole (sb, hole);
+ }
+}
+
+always_inline u32
+scoreboard_hole_bytes (sack_scoreboard_hole_t * hole)
+{
+ return hole->end - hole->start;
+}
+
+always_inline void
+tcp_cc_algo_register (tcp_cc_algorithm_type_e type,
+ const tcp_cc_algorithm_t * vft)
+{
+ tcp_main_t *tm = vnet_get_tcp_main ();
+ vec_validate (tm->cc_algos, type);
+
+ tm->cc_algos[type] = *vft;
+}
+
+always_inline tcp_cc_algorithm_t *
+tcp_cc_algo_get (tcp_cc_algorithm_type_e type)
+{
+ tcp_main_t *tm = vnet_get_tcp_main ();
+ return &tm->cc_algos[type];
+}
+
+void tcp_cc_init (tcp_connection_t * tc);
+
+/**
+ * Push TCP header to buffer
+ *
+ * @param vm - vlib_main
+ * @param b - buffer to write the header to
+ * @param sp_net - source port net order
+ * @param dp_net - destination port net order
+ * @param seq - sequence number net order
+ * @param ack - ack number net order
+ * @param tcp_hdr_opts_len - header and options length in bytes
+ * @param flags - header flags
+ * @param wnd - window size
+ *
+ * @return - pointer to start of TCP header
+ */
+always_inline void *
+vlib_buffer_push_tcp_net_order (vlib_buffer_t * b, u16 sp, u16 dp, u32 seq,
+ u32 ack, u8 tcp_hdr_opts_len, u8 flags,
+ u16 wnd)
+{
+ tcp_header_t *th;
+
+ th = vlib_buffer_push_uninit (b, tcp_hdr_opts_len);
+
+ th->src_port = sp;
+ th->dst_port = dp;
+ th->seq_number = seq;
+ th->ack_number = ack;
+ th->data_offset_and_reserved = (tcp_hdr_opts_len >> 2) << 4;
+ th->flags = flags;
+ th->window = wnd;
+ th->checksum = 0;
+ th->urgent_pointer = 0;
+ return th;
+}
+
+/**
+ * Push TCP header to buffer
+ *
+ * @param vm - vlib_main
+ * @param b - buffer to write the header to
+ * @param sp_net - source port net order
+ * @param dp_net - destination port net order
+ * @param seq - sequence number host order
+ * @param ack - ack number host order
+ * @param tcp_hdr_opts_len - header and options length in bytes
+ * @param flags - header flags
+ * @param wnd - window size
+ *
+ * @return - pointer to start of TCP header
+ */
+always_inline void *
+vlib_buffer_push_tcp (vlib_buffer_t * b, u16 sp_net, u16 dp_net, u32 seq,
+ u32 ack, u8 tcp_hdr_opts_len, u8 flags, u16 wnd)
+{
+ return vlib_buffer_push_tcp_net_order (b, sp_net, dp_net,
+ clib_host_to_net_u32 (seq),
+ clib_host_to_net_u32 (ack),
+ tcp_hdr_opts_len, flags,
+ clib_host_to_net_u16 (wnd));
+}
+
+#endif /* _vnet_tcp_h_ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */