include/linux/tcp.h

1 /* SPDX-License-Identifier: GPL-2.0-or-later */
31 	return th->doff * 4;  in __tcp_hdrlen()
46 	return inner_tcp_hdr(skb)->doff * 4;  in inner_tcp_hdrlen()
50  * skb_tcp_all_headers - Returns size of all headers for a TCP packet
53  * Used in TX path, for a packet known to be a TCP one.
65  * skb_inner_tcp_all_headers - Returns size of all headers for an encap TCP packet
68  * Used in TX path, for a packet known to be a TCP one.
70  * if (skb_is_gso(skb) && skb->encapsulation) {
81 	return (tcp_hdr(skb)->doff - 5) * 4;  in tcp_optlen()
107 /*These are used to set the sack_ok field in struct tcp_options_received */
117 	u16 	saw_tstamp : 1,	/* Saw TIMESTAMP on last packet		*/
119 		dsack : 1,	/* D-SACK is scheduled			*/
134 	rx_opt->tstamp_ok = rx_opt->sack_ok = 0;  in tcp_clear_options()
135 	rx_opt->wscale_ok = rx_opt->snd_wscale = 0;  in tcp_clear_options()
137 	rx_opt->smc_ok = 0;  in tcp_clear_options()
163 	u32				last_oow_ack_time; /* last SYNACK */
166 						  * after data-in-SYN.
186 	return tcp_rsk(req)->used_tcp_ao;  in tcp_rsk_used_ao()
201 	/* TX read-mostly hotpath cache lines */
203 	/* timestamp of last sent data packet (for restart window) */
214 	/* TXRX read-mostly hotpath cache lines */
232 	/* RX read-mostly hotpath cache lines */
235 	u32	rcv_tstamp;	/* timestamp of last received ACK (for keepalives) */
249 	/* TX read-write hotpath cache lines */
260 	u32	snd_sml;	/* Last byte of the most recently transmitted small packet */
264 	u32	pushed_seq;	/* Last pushed seq, required to talk to windows */
268 	u64	tcp_clock_cache; /* cache last tcp_clock_ns() (see tcp_mstamp_refresh()) */
271 	struct list_head tsorted_sent_queue; /* time-sorted sent but un-SACKed skbs */
280 	/* TXRX read-write hotpath cache lines */
299  *      Options received (usually on last packet, some only on SYN packets).
306 	/* RX read-write hotpath cache lines */
319 	u32	rcv_wup;	/* rcv_nxt on last window update sent	*/
320 	u32	max_packets_out;  /* max packets_out in last window */
353 	u32	last_oow_ack_time;  /* timestamp of last out-of-window ACK */
362 		u32 last_delivered; /* tp->delivered at last reo_wnd adj */
365 		u8 reo_wnd_persist:5, /* No. of recovery since last adj */
366 		   dsack_seen:1, /* Whether DSACK seen after last adj */
367 		   advanced:1;	 /* mstamp advanced since last lost marking */
378 		frto        : 1;/* F-RTO (RFC5682) activated in CA_Loss */
384 		syn_fastopen_ch:1, /* Active TFO re-enabling probe */
385 		syn_data_acked:1;/* data in SYN is acked by SYN-ACK */
390 	u32	mdev_max_us;	/* maximal mdev for the last rtt period	*/
412 	struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
422 	u32	retrans_stamp;	/* Timestamp of the last retransmit,
423 				 * also used in SYN-SENT to remember stamp of
431 	u32	rto_stamp;	/* Start time (ms) of last CA_Loss recovery */
433 				 * SYN/SYN-ACK and recurring timeouts.
454 					  * it is to avoid the bpf_tcp_cc->init()
458 #define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_cb_flags & ARG)
463 	u16 timeout_rehash;	/* Timeout-triggered rehash attempts */
465 	u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */
467 /* TCP-specific MTU probe information. */
472 	u32     plb_rehash;     /* PLB-triggered rehash attempts */
485 /* TCP AF-Specific parts; only used by TCP-AO/MD5 Signature support so far */
500 	 * socket. Used to retransmit SYNACKs etc.
531  * Used in context of (lockless) tcp listeners.
543 	/* The time we sent the last out-of-window ACK: */
563 	return sk->sk_state == TCP_SYN_RECV &&  in tcp_passive_fastopen()
564 	       rcu_access_pointer(tcp_sk(sk)->fastopen_rsk) != NULL;  in tcp_passive_fastopen()
569 	struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;  in fastopen_queue_tune()
570 	int somaxconn = READ_ONCE(sock_net(sk)->core.sysctl_somaxconn);  in fastopen_queue_tune()
572 	WRITE_ONCE(queue->fastopenq.max_qlen, min_t(unsigned int, backlog, somaxconn));  in fastopen_queue_tune()
578 	tp->saved_syn = req->saved_syn;  in tcp_move_syn()
579 	req->saved_syn = NULL;  in tcp_move_syn()
584 	kfree(tp->saved_syn);  in tcp_saved_syn_free()
585 	tp->saved_syn = NULL;  in tcp_saved_syn_free()
590 	return saved_syn->mac_hdrlen + saved_syn->network_hdrlen +  in tcp_saved_syn_len()
591 		saved_syn->tcp_hdrlen;  in tcp_saved_syn_len()
603 	u16 user_mss = READ_ONCE(tp->rx_opt.user_mss);  in tcp_mss_clamp()