tcp_types.h

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/*
 * Copyright (c) 2020 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 SRC_VNET_TCP_TCP_TYPES_H_
#define SRC_VNET_TCP_TCP_TYPES_H_

#include <vppinfra/clib.h>
#include <vppinfra/rbtree.h>
#include <vnet/tcp/tcp_packet.h>
#include <vnet/session/transport.h>
#include <vppinfra/tw_timer_16t_2w_512sl.h>

#define TCP_TICK 0.001                  /**< TCP tick period (s) */
#define THZ (u32) (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_FIB_RECHECK_PERIOD  1 * THZ /**< Recheck every 1s */
#define TCP_MAX_OPTION_SPACE 40
#define TCP_CC_DATA_SZ 24
#define TCP_MAX_GSO_SZ 65536
#define TCP_RXT_MAX_BURST 10

#define TCP_DUPACK_THRESHOLD    3
#define TCP_IW_N_SEGMENTS       10
#define TCP_ALWAYS_ACK          1       /**< On/off delayed acks */
#define TCP_USE_SACKS           1       /**< Disable only for testing */

/** 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;

/** TCP timers */
#define foreach_tcp_timer               \
  _(RETRANSMIT, "RETRANSMIT")           \
  _(DELACK, "DELAYED ACK")              \
  _(PERSIST, "PERSIST")                 \
  _(WAITCLOSE, "WAIT CLOSE")            \
  _(RETRANSMIT_SYN, "RETRANSMIT SYN")   \

typedef enum _tcp_timers
{
#define _(sym, str) TCP_TIMER_##sym,
  foreach_tcp_timer
#undef _
  TCP_N_TIMERS
} tcp_timers_e;

#define TCP_TIMER_HANDLE_INVALID ((u32) ~0)

#define TCP_TIMER_TICK          0.1             /**< Timer tick in seconds */
#define TCP_TO_TIMER_TICK       TCP_TICK*10     /**< Factor for converting
                                                     ticks to timer ticks */

#define TCP_RTO_MAX 60 * THZ    /* Min max RTO (60s) as per RFC6298 */
#define TCP_RTO_MIN 0.2 * THZ   /* Min RTO (200ms) - lower than standard */
#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 */
#define TCP_RTO_BOFF_MAX 8      /* Max number of retries before reset */
#define TCP_ESTABLISH_TIME (60 * THZ)   /* Connection establish timeout */

/** Connection configuration flags */
#define foreach_tcp_cfg_flag                    \
  _(RATE_SAMPLE, "Rate sampling")               \
  _(NO_CSUM_OFFLOAD, "No csum offload")         \
  _(NO_TSO, "TSO off")                          \
  _(TSO, "TSO")                                 \
  _(NO_ENDPOINT,"No endpoint")                  \

typedef enum tcp_cfg_flag_bits_
{
#define _(sym, str) TCP_CFG_F_##sym##_BIT,
  foreach_tcp_cfg_flag
#undef _
  TCP_CFG_N_FLAG_BITS
} tcp_cfg_flag_bits_e;

typedef enum tcp_cfg_flag_
{
#define _(sym, str) TCP_CFG_F_##sym = 1 << TCP_CFG_F_##sym##_BIT,
  foreach_tcp_cfg_flag
#undef _
  TCP_CFG_N_FLAGS
} tcp_cfg_flags_e;

/** TCP connection flags */
#define foreach_tcp_connection_flag             \
  _(SNDACK, "Send ACK")                         \
  _(FINSNT, "FIN sent")                         \
  _(RECOVERY, "Recovery")                       \
  _(FAST_RECOVERY, "Fast Recovery")             \
  _(DCNT_PENDING, "Disconnect pending")         \
  _(HALF_OPEN_DONE, "Half-open completed")      \
  _(FINPNDG, "FIN pending")                     \
  _(RXT_PENDING, "Retransmit pending")          \
  _(FRXT_FIRST, "Retransmit first")             \
  _(DEQ_PENDING, "Dequeue pending ")            \
  _(PSH_PENDING, "PSH pending")                 \
  _(FINRCVD, "FIN received")                    \
  _(ZERO_RWND_SENT, "Zero RWND sent")           \

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;

#define TCP_SCOREBOARD_TRACE (0)
#define TCP_MAX_SACK_BLOCKS 255 /**< Max number of SACK blocks stored */
#define TCP_INVALID_SACK_HOLE_INDEX ((u32)~0)

typedef struct _scoreboard_trace_elt
{
  u32 start;
  u32 end;
  u32 ack;
  u32 snd_una_max;
  u32 group;
} scoreboard_trace_elt_t;

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 */
  u8 is_lost;           /**< Mark hole as lost */
} sack_scoreboard_hole_t;

typedef struct _sack_scoreboard
{
  sack_scoreboard_hole_t *holes;        /**< Pool of holes */
  u32 head;                             /**< Index of first entry */
  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;             /**< Sack bytes delivered to app */
  u32 rxt_sacked;                       /**< Rxt bytes last delivered */
  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 last_lost_bytes;                  /**< Number of bytes last lost */
  u32 cur_rxt_hole;                     /**< Retransmitting from this hole */
  u8 is_reneging;

#if TCP_SCOREBOARD_TRACE
  scoreboard_trace_elt_t *trace;
#endif

} sack_scoreboard_t;

#define TCP_BTS_INVALID_INDEX   ((u32)~0)

typedef enum tcp_bts_flags_
{
  TCP_BTS_IS_RXT = 1,
  TCP_BTS_IS_APP_LIMITED = 1 << 1,
  TCP_BTS_IS_SACKED = 1 << 2,
  TCP_BTS_IS_RXT_LOST = 1 << 3,
} __clib_packed tcp_bts_flags_t;

typedef struct tcp_bt_sample_
{
  u32 next;                     /**< Next sample index in list */
  u32 prev;                     /**< Previous sample index in list */
  u32 min_seq;                  /**< Min seq number in sample */
  u32 max_seq;                  /**< Max seq number. Set for rxt samples */
  u64 delivered;                /**< Total delivered bytes for sample */
  f64 delivered_time;           /**< Delivered time when sample taken */
  f64 tx_time;                  /**< Transmit time for the burst */
  f64 first_tx_time;            /**< Connection first tx time at tx */
  u64 tx_in_flight;             /**< In flight at tx time */
  u64 tx_lost;                  /**< Lost at tx time */
  tcp_bts_flags_t flags;        /**< Sample flag */
} tcp_bt_sample_t;

typedef struct tcp_rate_sample_
{
  u64 prior_delivered;          /**< Delivered of sample used for rate, i.e.,
                                     total bytes delivered at prior_time */
  f64 prior_time;               /**< Delivered time of sample used for rate */
  f64 interval_time;            /**< Time to ack the bytes delivered */
  f64 rtt_time;                 /**< RTT for sample */
  u64 tx_in_flight;             /**< In flight at (re)transmit time */
  u64 tx_lost;                  /**< Lost over interval */
  u32 delivered;                /**< Bytes delivered in interval_time */
  u32 acked_and_sacked;         /**< Bytes acked + sacked now */
  u32 last_lost;                /**< Bytes lost now */
  u32 lost;                     /**< Number of bytes lost over interval */
  tcp_bts_flags_t flags;        /**< Rate sample flags from bt sample */
} tcp_rate_sample_t;

typedef struct tcp_byte_tracker_
{
  tcp_bt_sample_t *samples;     /**< Pool of samples */
  rb_tree_t sample_lookup;      /**< Rbtree for sample lookup by min_seq */
  u32 head;                     /**< Head of samples linked list */
  u32 tail;                     /**< Tail of samples linked list */
  u32 last_ooo;                 /**< Cached last ooo sample */
} tcp_byte_tracker_t;

typedef enum _tcp_cc_algorithm_type
{
  TCP_CC_NEWRENO,
  TCP_CC_CUBIC,
  TCP_CC_LAST = TCP_CC_CUBIC
} 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 enum tcp_cc_event_
{
  TCP_CC_EVT_START_TX,
} tcp_cc_event_t;

/*
 * As per RFC4898 tcpEStatsStackSoftErrors
 */
typedef struct tcp_errors_
{
  u32 below_data_wnd;   /**< All data in seg is below snd_una */
  u32 above_data_wnd;   /**< Some data in segment is above snd_wnd */
  u32 below_ack_wnd;    /**< Acks for data below snd_una */
  u32 above_ack_wnd;    /**< Acks for data not sent */
} tcp_errors_t;

typedef struct _tcp_connection
{
  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  transport_connection_t connection;  /**< Common transport data. First! */

  u8 state;                     /**< TCP state as per tcp_state_t */
  u8 cfg_flags;                 /**< Connection configuration flags */
  u16 flags;                    /**< Connection flags (see tcp_conn_flags_e) */
  u32 timers[TCP_N_TIMERS];     /**< Timer handles into timer wheel */

  u64 segs_in;          /** RFC4022/4898 tcpHCInSegs/tcpEStatsPerfSegsIn */
  u64 bytes_in;         /** RFC4898 tcpEStatsPerfHCDataOctetsIn */
  u64 segs_out;         /** RFC4898 tcpEStatsPerfSegsOut */
  u64 bytes_out;        /** RFC4898 tcpEStatsPerfHCDataOctetsOut */

  /** 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 */
  u16 snd_mss;          /**< Effective send max seg (data) size */

  u64 data_segs_in;     /** RFC4898 tcpEStatsPerfDataSegsIn */
  u64 data_segs_out;    /** RFC4898 tcpEStatsPerfDataSegsOut */

  /** 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 */
  u8 snd_opts_len;              /**< Tx options len */
  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*/
  tcp_options_t snd_opts;       /**< Tx options for connection */
  tcp_options_t rcv_opts;       /**< Rx options for connection */

  sack_block_t *snd_sacks;      /**< Vector of SACKs to send. XXX Fixed size? */
  u8 snd_sack_pos;              /**< Position in vec of first block to send */
  sack_block_t *snd_sacks_fl;   /**< Vector for building new list */
  sack_scoreboard_t sack_sb;    /**< SACK "scoreboard" that tracks holes */

  u16 rcv_dupacks;      /**< Number of recent DUPACKs received */
  u32 dupacks_in;       /**< RFC4898 tcpEStatsStackDupAcksIn*/
  u8 pending_dupacks;   /**< Number of DUPACKs to be sent */
  u32 dupacks_out;      /**< RFC4898 tcpEStatsPathDupAcksOut */

  /* Congestion control */
  u32 cwnd;             /**< Congestion window */
  u32 cwnd_acc_bytes;   /**< Bytes accumulated for cwnd increment */
  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 burst_acked;      /**< Bytes acknowledged in current burst */
  u32 snd_rxt_bytes;    /**< Retransmitted bytes during current cc event */
  u32 snd_rxt_ts;       /**< Timestamp when first packet is retransmitted */
  u32 prr_delivered;    /**< RFC6937 bytes delivered during current event */
  u32 prr_start;        /**< snd_una when prr starts */
  u32 rxt_delivered;    /**< Rxt bytes delivered during current cc event */
  u32 rxt_head;         /**< snd_una last time we re rxted the head */
  u32 tsecr_last_ack;   /**< Timestamp echoed to us in last healthy ACK */
  u32 snd_congestion;   /**< snd_una_max when congestion is detected */
  u32 tx_fifo_size;     /**< Tx fifo size. Used to constrain cwnd */
  tcp_cc_algorithm_t *cc_algo;  /**< Congestion control algorithm */
  u8 cc_data[TCP_CC_DATA_SZ];   /**< Congestion control algo private data */

  u32 fr_occurences;    /**< fast-retransmit occurrences RFC4898
                             tcpEStatsStackFastRetran */
  u32 tr_occurences;    /**< timer-retransmit occurrences */
  u64 bytes_retrans;    /**< RFC4898 tcpEStatsPerfOctetsRetrans */
  u64 segs_retrans;     /**< RFC4898 tcpEStatsPerfSegsRetrans*/

  /* 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_seq;          /**< Sequence number for tracked ACK */
  f64 rtt_ts;           /**< Timestamp for tracked ACK */
  f64 mrtt_us;          /**< High precision mrtt from tracked acks */

  u32 psh_seq;          /**< Add psh header for seg that includes this */
  u32 next_node_index;  /**< Can be used to control next node in output */
  u32 next_node_opaque; /**< Opaque to pass to next node */
  u32 limited_transmit; /**< snd_nxt when limited transmit starts */
  u32 sw_if_index;      /**< Interface for the connection */

  /* Delivery rate estimation */
  u64 delivered;                /**< Total bytes delivered to peer */
  u64 app_limited;              /**< Delivered when app-limited detected */
  f64 delivered_time;           /**< Time last bytes were acked */
  f64 first_tx_time;            /**< Send time for recently delivered/sent */
  u64 lost;                     /**< Total bytes lost */
  tcp_byte_tracker_t *bt;       /**< Tx byte tracker */

  tcp_errors_t errors;  /**< Soft connection errors */

  f64 start_ts;         /**< Timestamp when connection initialized */
  u32 last_fib_check;   /**< Last time we checked fib route for peer */
  u16 mss;              /**< Our max seg size that includes options */
  u32 timestamp_delta;  /**< Offset for timestamp */
  u32 ipv6_flow_label;  /**< flow label for ipv6 header */

#define rst_state snd_wl1
} tcp_connection_t;

/* *INDENT-OFF* */
struct _tcp_cc_algorithm
{
  const char *name;
  uword (*unformat_cfg) (unformat_input_t * input);
  void (*init) (tcp_connection_t * tc);
  void (*cleanup) (tcp_connection_t * tc);
  void (*rcv_ack) (tcp_connection_t * tc, tcp_rate_sample_t *rs);
  void (*rcv_cong_ack) (tcp_connection_t * tc, tcp_cc_ack_t ack,
                        tcp_rate_sample_t *rs);
  void (*congestion) (tcp_connection_t * tc);
  void (*loss) (tcp_connection_t * tc);
  void (*recovered) (tcp_connection_t * tc);
  void (*undo_recovery) (tcp_connection_t * tc);
  void (*event) (tcp_connection_t *tc, tcp_cc_event_t evt);
  u64 (*get_pacing_rate) (tcp_connection_t *tc);
};
/* *INDENT-ON* */

#define tcp_fastrecovery_on(tc) (tc)->flags |= TCP_CONN_FAST_RECOVERY
#define tcp_fastrecovery_off(tc) (tc)->flags &= ~TCP_CONN_FAST_RECOVERY
#define tcp_recovery_on(tc) (tc)->flags |= TCP_CONN_RECOVERY
#define tcp_recovery_off(tc) (tc)->flags &= ~TCP_CONN_RECOVERY
#define tcp_in_fastrecovery(tc) ((tc)->flags & TCP_CONN_FAST_RECOVERY)
#define tcp_in_recovery(tc) ((tc)->flags & (TCP_CONN_RECOVERY))
#define tcp_in_slowstart(tc) (tc->cwnd < tc->ssthresh)
#define tcp_disconnect_pending(tc) ((tc)->flags & TCP_CONN_DCNT_PENDING)
#define tcp_disconnect_pending_on(tc) ((tc)->flags |= TCP_CONN_DCNT_PENDING)
#define tcp_disconnect_pending_off(tc) ((tc)->flags &= ~TCP_CONN_DCNT_PENDING)
#define tcp_fastrecovery_first(tc) ((tc)->flags & TCP_CONN_FRXT_FIRST)
#define tcp_fastrecovery_first_on(tc) ((tc)->flags |= TCP_CONN_FRXT_FIRST)
#define tcp_fastrecovery_first_off(tc) ((tc)->flags &= ~TCP_CONN_FRXT_FIRST)

#define tcp_in_cong_recovery(tc) ((tc)->flags &                 \
          (TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY))

always_inline void
tcp_cong_recovery_off (tcp_connection_t * tc)
{
  tc->flags &= ~(TCP_CONN_FAST_RECOVERY | TCP_CONN_RECOVERY);
  tcp_fastrecovery_first_off (tc);
}

#define tcp_csum_offload(tc) (!((tc)->cfg_flags & TCP_CFG_F_NO_CSUM_OFFLOAD))

#define tcp_zero_rwnd_sent(tc) ((tc)->flags & TCP_CONN_ZERO_RWND_SENT)
#define tcp_zero_rwnd_sent_on(tc) (tc)->flags |= TCP_CONN_ZERO_RWND_SENT
#define tcp_zero_rwnd_sent_off(tc) (tc)->flags &= ~TCP_CONN_ZERO_RWND_SENT

always_inline tcp_connection_t *
tcp_get_connection_from_transport (transport_connection_t * tconn)
{
  return (tcp_connection_t *) tconn;
}

typedef tw_timer_wheel_16t_2w_512sl_t tcp_timer_wheel_t;

#endif /* SRC_VNET_TCP_TCP_TYPES_H_ */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */