138 struct tcp_sock {  struct
140 	struct inet_connection_sock	inet_conn;
141 	u16	tcp_header_len;	/* Bytes of tcp header to send		*/
142 	u16	gso_segs;	/* Max number of segs per GSO packet	*/
148 	__be32	pred_flags;
155 	u64	bytes_received;	/* RFC4898 tcpEStatsAppHCThruOctetsReceived
159 	u32	segs_in;	/* RFC4898 tcpEStatsPerfSegsIn
162 	u32	data_segs_in;	/* RFC4898 tcpEStatsPerfDataSegsIn
165  	u32	rcv_nxt;	/* What we want to receive next 	*/
166 	u32	copied_seq;	/* Head of yet unread data		*/
167 	u32	rcv_wup;	/* rcv_nxt on last window update sent	*/
168  	u32	snd_nxt;	/* Next sequence we send		*/
169 	u32	segs_out;	/* RFC4898 tcpEStatsPerfSegsOut
172 	u32	data_segs_out;	/* RFC4898 tcpEStatsPerfDataSegsOut
175 	u64	bytes_sent;	/* RFC4898 tcpEStatsPerfHCDataOctetsOut
178 	u64	bytes_acked;	/* RFC4898 tcpEStatsAppHCThruOctetsAcked
182 	u32	dsack_dups;	/* RFC4898 tcpEStatsStackDSACKDups
185  	u32	snd_una;	/* First byte we want an ack for	*/
186  	u32	snd_sml;	/* Last byte of the most recently transmitted small packet */
187 	u32	rcv_tstamp;	/* timestamp of last received ACK (for keepalives) */
188 	u32	lsndtime;	/* timestamp of last sent data packet (for restart window) */
189 	u32	last_oow_ack_time;  /* timestamp of last out-of-window ACK */
190 	u32	compressed_ack_rcv_nxt;
192 	u32	tsoffset;	/* timestamp offset */
194 	struct list_head tsq_node; /* anchor in tsq_tasklet.head list */
195 	struct list_head tsorted_sent_queue; /* time-sorted sent but un-SACKed skbs */
197 	u32	snd_wl1;	/* Sequence for window update		*/
198 	u32	snd_wnd;	/* The window we expect to receive	*/
199 	u32	max_window;	/* Maximal window ever seen from peer	*/
200 	u32	mss_cache;	/* Cached effective mss, not including SACKS */
202 	u32	window_clamp;	/* Maximal window to advertise		*/
203 	u32	rcv_ssthresh;	/* Current window clamp			*/
206 	struct tcp_rack {
216 	} rack;
217 	u16	advmss;		/* Advertised MSS			*/
218 	u8	compressed_ack;
219 	u32	chrono_start;	/* Start time in jiffies of a TCP chrono */
220 	u32	chrono_stat[3];	/* Time in jiffies for chrono_stat stats */
221 	u8	chrono_type:2,	/* current chronograph type */
222 		rate_app_limited:1,  /* rate_{delivered,interval_us} limited? */
223 		fastopen_connect:1, /* FASTOPEN_CONNECT sockopt */
224 		fastopen_no_cookie:1, /* Allow send/recv SYN+data without a cookie */
225 		is_sack_reneg:1,    /* in recovery from loss with SACK reneg? */
226 		unused:2;
227 	u8	nonagle     : 4,/* Disable Nagle algorithm?             */
228 		thin_lto    : 1,/* Use linear timeouts for thin streams */
229 		recvmsg_inq : 1,/* Indicate # of bytes in queue upon recvmsg */
230 		repair      : 1,
231 		frto        : 1;/* F-RTO (RFC5682) activated in CA_Loss */
232 	u8	repair_queue;
233 	u8	syn_data:1,	/* SYN includes data */
234 		syn_fastopen:1,	/* SYN includes Fast Open option */
235 		syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */
236 		syn_fastopen_ch:1, /* Active TFO re-enabling probe */
237 		syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
238 		save_syn:1,	/* Save headers of SYN packet */
239 		is_cwnd_limited:1,/* forward progress limited by snd_cwnd? */
240 		syn_smc:1;	/* SYN includes SMC */
241 	u32	tlp_high_seq;	/* snd_nxt at the time of TLP retransmit. */
243 	u32	tcp_tx_delay;	/* delay (in usec) added to TX packets */
244 	u64	tcp_wstamp_ns;	/* departure time for next sent data packet */
245 	u64	tcp_clock_cache; /* cache last tcp_clock_ns() (see tcp_mstamp_refresh()) */
248 	u64	tcp_mstamp;	/* most recent packet received/sent */
249 	u32	srtt_us;	/* smoothed round trip time << 3 in usecs */
250 	u32	mdev_us;	/* medium deviation			*/
251 	u32	mdev_max_us;	/* maximal mdev for the last rtt period	*/
252 	u32	rttvar_us;	/* smoothed mdev_max			*/
253 	u32	rtt_seq;	/* sequence number to update rttvar	*/
254 	struct  minmax rtt_min;
256 	u32	packets_out;	/* Packets which are "in flight"	*/
257 	u32	retrans_out;	/* Retransmitted packets out		*/
258 	u32	max_packets_out;  /* max packets_out in last window */
259 	u32	max_packets_seq;  /* right edge of max_packets_out flight */
261 	u16	urg_data;	/* Saved octet of OOB data and control flags */
262 	u8	ecn_flags;	/* ECN status bits.			*/
263 	u8	keepalive_probes; /* num of allowed keep alive probes	*/
264 	u32	reordering;	/* Packet reordering metric.		*/
265 	u32	reord_seen;	/* number of data packet reordering events */
266 	u32	snd_up;		/* Urgent pointer		*/
271 	struct tcp_options_received rx_opt;
276  	u32	snd_ssthresh;	/* Slow start size threshold		*/
277  	u32	snd_cwnd;	/* Sending congestion window		*/
278 	u32	snd_cwnd_cnt;	/* Linear increase counter		*/
279 	u32	snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
280 	u32	snd_cwnd_used;
281 	u32	snd_cwnd_stamp;
282 	u32	prior_cwnd;	/* cwnd right before starting loss recovery */
283 	u32	prr_delivered;	/* Number of newly delivered packets to
285 	u32	prr_out;	/* Total number of pkts sent during Recovery. */
286 	u32	delivered;	/* Total data packets delivered incl. rexmits */
287 	u32	delivered_ce;	/* Like the above but only ECE marked packets */
288 	u32	lost;		/* Total data packets lost incl. rexmits */
289 	u32	app_limited;	/* limited until "delivered" reaches this val */
290 	u64	first_tx_mstamp;  /* start of window send phase */
291 	u64	delivered_mstamp; /* time we reached "delivered" */
292 	u32	rate_delivered;    /* saved rate sample: packets delivered */
293 	u32	rate_interval_us;  /* saved rate sample: time elapsed */
295  	u32	rcv_wnd;	/* Current receiver window		*/
296 	u32	write_seq;	/* Tail(+1) of data held in tcp send buffer */
297 	u32	notsent_lowat;	/* TCP_NOTSENT_LOWAT */
298 	u32	pushed_seq;	/* Last pushed seq, required to talk to windows */
299 	u32	lost_out;	/* Lost packets			*/
300 	u32	sacked_out;	/* SACK'd packets			*/
302 	struct hrtimer	pacing_timer;
303 	struct hrtimer	compressed_ack_timer;
306 	struct sk_buff* lost_skb_hint;
307 	struct sk_buff *retransmit_skb_hint;
310 	struct rb_root	out_of_order_queue;
311 	struct sk_buff	*ooo_last_skb; /* cache rb_last(out_of_order_queue) */
314 	struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
315 	struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
317 	struct tcp_sack_block recv_sack_cache[4];
319 	struct sk_buff *highest_sack;   /* skb just after the highest
325 	int     lost_cnt_hint;
327 	u32	prior_ssthresh; /* ssthresh saved at recovery start	*/
328 	u32	high_seq;	/* snd_nxt at onset of congestion	*/
330 	u32	retrans_stamp;	/* Timestamp of the last retransmit,
333 	u32	undo_marker;	/* snd_una upon a new recovery episode. */
334 	int	undo_retrans;	/* number of undoable retransmissions. */
335 	u64	bytes_retrans;	/* RFC4898 tcpEStatsPerfOctetsRetrans
338 	u32	total_retrans;	/* Total retransmits for entire connection */
340 	u32	urg_seq;	/* Seq of received urgent pointer */
341 	unsigned int		keepalive_time;	  /* time before keep alive takes place */
342 	unsigned int		keepalive_intvl;  /* time interval between keep alive probes */
344 	int			linger2;
349 	u8	bpf_sock_ops_cb_flags;  /* Control calling BPF programs
357 	u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */
360 	u32 rcv_rtt_last_tsecr;
361 	struct {
385 	const struct tcp_sock_af_ops	*af_specific;  argument
388 	struct tcp_md5sig_info	__rcu *md5sig_info;
392 	struct tcp_fastopen_request *fastopen_req;
396 	struct request_sock __rcu *fastopen_rsk;
420 static inline struct tcp_sock *tcp_sk(const struct sock *sk)  in tcp_sk()  argument