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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_MAX_RX_FIFO_SIZE 2 << 20
#define TCP_IW_N_SEGMENTS 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 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:
*/