144 struct tcp_sock {  struct
146 	struct inet_connection_sock	inet_conn;
147 	u16	tcp_header_len;	/* Bytes of tcp header to send		*/
148 	u16	gso_segs;	/* Max number of segs per GSO packet	*/
154 	__be32	pred_flags;
161 	u64	bytes_received;	/* RFC4898 tcpEStatsAppHCThruOctetsReceived
165 	u32	segs_in;	/* RFC4898 tcpEStatsPerfSegsIn
168 	u32	data_segs_in;	/* RFC4898 tcpEStatsPerfDataSegsIn
171  	u32	rcv_nxt;	/* What we want to receive next 	*/
172 	u32	copied_seq;	/* Head of yet unread data		*/
173 	u32	rcv_wup;	/* rcv_nxt on last window update sent	*/
174  	u32	snd_nxt;	/* Next sequence we send		*/
175 	u32	segs_out;	/* RFC4898 tcpEStatsPerfSegsOut
178 	u32	data_segs_out;	/* RFC4898 tcpEStatsPerfDataSegsOut
181 	u64	bytes_acked;	/* RFC4898 tcpEStatsAppHCThruOctetsAcked
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 */
191 	u32	tsoffset;	/* timestamp offset */
193 	struct list_head tsq_node; /* anchor in tsq_tasklet.head list */
195 	u32	snd_wl1;	/* Sequence for window update		*/
196 	u32	snd_wnd;	/* The window we expect to receive	*/
197 	u32	max_window;	/* Maximal window ever seen from peer	*/
198 	u32	mss_cache;	/* Cached effective mss, not including SACKS */
200 	u32	window_clamp;	/* Maximal window to advertise		*/
201 	u32	rcv_ssthresh;	/* Current window clamp			*/
204 	struct tcp_rack {
210 	} rack;
211 	u16	advmss;		/* Advertised MSS			*/
212 	u32	chrono_start;	/* Start time in jiffies of a TCP chrono */
213 	u32	chrono_stat[3];	/* Time in jiffies for chrono_stat stats */
214 	u8	chrono_type:2,	/* current chronograph type */
215 		rate_app_limited:1,  /* rate_{delivered,interval_us} limited? */
216 		fastopen_connect:1, /* FASTOPEN_CONNECT sockopt */
217 		is_sack_reneg:1,    /* in recovery from loss with SACK reneg? */
218 		unused:3;
219 	u8	nonagle     : 4,/* Disable Nagle algorithm?             */
220 		thin_lto    : 1,/* Use linear timeouts for thin streams */
221 		unused1	    : 1,
222 		repair      : 1,
223 		frto        : 1;/* F-RTO (RFC5682) activated in CA_Loss */
224 	u8	repair_queue;
225 	u8	syn_data:1,	/* SYN includes data */
226 		syn_fastopen:1,	/* SYN includes Fast Open option */
227 		syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */
228 		syn_fastopen_ch:1, /* Active TFO re-enabling probe */
229 		syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
230 		save_syn:1,	/* Save headers of SYN packet */
231 		is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */
232 	u32	tlp_high_seq;	/* snd_nxt at the time of TLP retransmit. */
235 	u64	tcp_mstamp;	/* most recent packet received/sent */
236 	u32	srtt_us;	/* smoothed round trip time << 3 in usecs */
237 	u32	mdev_us;	/* medium deviation			*/
238 	u32	mdev_max_us;	/* maximal mdev for the last rtt period	*/
239 	u32	rttvar_us;	/* smoothed mdev_max			*/
240 	u32	rtt_seq;	/* sequence number to update rttvar	*/
241 	struct  minmax rtt_min;
243 	u32	packets_out;	/* Packets which are "in flight"	*/
244 	u32	retrans_out;	/* Retransmitted packets out		*/
245 	u32	max_packets_out;  /* max packets_out in last window */
246 	u32	max_packets_seq;  /* right edge of max_packets_out flight */
248 	u16	urg_data;	/* Saved octet of OOB data and control flags */
249 	u8	ecn_flags;	/* ECN status bits.			*/
250 	u8	keepalive_probes; /* num of allowed keep alive probes	*/
251 	u32	reordering;	/* Packet reordering metric.		*/
252 	u32	snd_up;		/* Urgent pointer		*/
257 	struct tcp_options_received rx_opt;
262  	u32	snd_ssthresh;	/* Slow start size threshold		*/
263  	u32	snd_cwnd;	/* Sending congestion window		*/
264 	u32	snd_cwnd_cnt;	/* Linear increase counter		*/
265 	u32	snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
266 	u32	snd_cwnd_used;
267 	u32	snd_cwnd_stamp;
268 	u32	prior_cwnd;	/* cwnd right before starting loss recovery */
269 	u32	prr_delivered;	/* Number of newly delivered packets to
271 	u32	prr_out;	/* Total number of pkts sent during Recovery. */
272 	u32	delivered;	/* Total data packets delivered incl. rexmits */
273 	u32	lost;		/* Total data packets lost incl. rexmits */
274 	u32	app_limited;	/* limited until "delivered" reaches this val */
275 	u64	first_tx_mstamp;  /* start of window send phase */
276 	u64	delivered_mstamp; /* time we reached "delivered" */
277 	u32	rate_delivered;    /* saved rate sample: packets delivered */
278 	u32	rate_interval_us;  /* saved rate sample: time elapsed */
280  	u32	rcv_wnd;	/* Current receiver window		*/
281 	u32	write_seq;	/* Tail(+1) of data held in tcp send buffer */
282 	u32	notsent_lowat;	/* TCP_NOTSENT_LOWAT */
283 	u32	pushed_seq;	/* Last pushed seq, required to talk to windows */
284 	u32	lost_out;	/* Lost packets			*/
285 	u32	sacked_out;	/* SACK'd packets			*/
286 	u32	fackets_out;	/* FACK'd packets			*/
288 	struct hrtimer	pacing_timer;
291 	struct sk_buff* lost_skb_hint;
292 	struct sk_buff *retransmit_skb_hint;
295 	struct rb_root	out_of_order_queue;
296 	struct sk_buff	*ooo_last_skb; /* cache rb_last(out_of_order_queue) */
299 	struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
300 	struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
302 	struct tcp_sack_block recv_sack_cache[4];
304 	struct sk_buff *highest_sack;   /* skb just after the highest
310 	int     lost_cnt_hint;
312 	u32	prior_ssthresh; /* ssthresh saved at recovery start	*/
313 	u32	high_seq;	/* snd_nxt at onset of congestion	*/
315 	u32	retrans_stamp;	/* Timestamp of the last retransmit,
318 	u32	undo_marker;	/* snd_una upon a new recovery episode. */
319 	int	undo_retrans;	/* number of undoable retransmissions. */
320 	u32	total_retrans;	/* Total retransmits for entire connection */
322 	u32	urg_seq;	/* Seq of received urgent pointer */
323 	unsigned int		keepalive_time;	  /* time before keep alive takes place */
324 	unsigned int		keepalive_intvl;  /* time interval between keep alive probes */
326 	int			linger2;
329 	struct {
353 	const struct tcp_sock_af_ops	*af_specific;  argument
356 	struct tcp_md5sig_info	__rcu *md5sig_info;
360 	struct tcp_fastopen_request *fastopen_req;
364 	struct request_sock *fastopen_rsk;
388 static inline struct tcp_sock *tcp_sk(const struct sock *sk)  in tcp_sk()  argument