VPP-598: tcp stack initial commit

Change-Id: I49e5ce0aae6e4ff634024387ceaf7dbc432a0351
Signed-off-by: Dave Barach <dave@barachs.net>
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 624 insertions, 0 deletions

diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
new file mode 100644
index 00000000000..22f00a63273
--- /dev/null
+++ b/src/vnet/tcp/tcp.h
@@ -0,0 +1,624 @@
+/*
+ * 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:
+ */