summaryrefslogtreecommitdiffstats
path: root/include/linux/tcp.h
blob: 67c789ae719c7f6216870db74df3afc0223de66b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Definitions for the TCP protocol.
 *
 * Version:	@(#)tcp.h	1.0.2	04/28/93
 *
 * Author:	Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */
#ifndef _LINUX_TCP_H
#define _LINUX_TCP_H

#include <linux/types.h>
#include <asm/byteorder.h>
#include <linux/socket.h>

struct tcphdr {
	__be16	source;
	__be16	dest;
	__be32	seq;
	__be32	ack_seq;
#if defined(__LITTLE_ENDIAN_BITFIELD)
	__u16	res1:4,
		doff:4,
		fin:1,
		syn:1,
		rst:1,
		psh:1,
		ack:1,
		urg:1,
		ece:1,
		cwr:1;
#elif defined(__BIG_ENDIAN_BITFIELD)
	__u16	doff:4,
		res1:4,
		cwr:1,
		ece:1,
		urg:1,
		ack:1,
		psh:1,
		rst:1,
		syn:1,
		fin:1;
#else
#error	"Adjust your <asm/byteorder.h> defines"
#endif	
	__be16	window;
	__sum16	check;
	__be16	urg_ptr;
};

/*
 *	The union cast uses a gcc extension to avoid aliasing problems
 *  (union is compatible to any of its members)
 *  This means this part of the code is -fstrict-aliasing safe now.
 */
union tcp_word_hdr { 
	struct tcphdr hdr;
	__be32 		  words[5];
}; 

#define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3]) 

enum { 
	TCP_FLAG_CWR = __constant_cpu_to_be32(0x00800000),
	TCP_FLAG_ECE = __constant_cpu_to_be32(0x00400000),
	TCP_FLAG_URG = __constant_cpu_to_be32(0x00200000),
	TCP_FLAG_ACK = __constant_cpu_to_be32(0x00100000),
	TCP_FLAG_PSH = __constant_cpu_to_be32(0x00080000),
	TCP_FLAG_RST = __constant_cpu_to_be32(0x00040000),
	TCP_FLAG_SYN = __constant_cpu_to_be32(0x00020000),
	TCP_FLAG_FIN = __constant_cpu_to_be32(0x00010000),
	TCP_RESERVED_BITS = __constant_cpu_to_be32(0x0F000000),
	TCP_DATA_OFFSET = __constant_cpu_to_be32(0xF0000000)
}; 

/*
 * TCP general constants
 */
#define TCP_MSS_DEFAULT		 536U	/* IPv4 (RFC1122, RFC2581) */
#define TCP_MSS_DESIRED		1220U	/* IPv6 (tunneled), EDNS0 (RFC3226) */

/* TCP socket options */
#define TCP_NODELAY		1	/* Turn off Nagle's algorithm. */
#define TCP_MAXSEG		2	/* Limit MSS */
#define TCP_CORK		3	/* Never send partially complete segments */
#define TCP_KEEPIDLE		4	/* Start keeplives after this period */
#define TCP_KEEPINTVL		5	/* Interval between keepalives */
#define TCP_KEEPCNT		6	/* Number of keepalives before death */
#define TCP_SYNCNT		7	/* Number of SYN retransmits */
#define TCP_LINGER2		8	/* Life time of orphaned FIN-WAIT-2 state */
#define TCP_DEFER_ACCEPT	9	/* Wake up listener only when data arrive */
#define TCP_WINDOW_CLAMP	10	/* Bound advertised window */
#define TCP_INFO		11	/* Information about this connection. */
#define TCP_QUICKACK		12	/* Block/reenable quick acks */
#define TCP_CONGESTION		13	/* Congestion control algorithm */
#define TCP_MD5SIG		14	/* TCP MD5 Signature (RFC2385) */
#define TCP_COOKIE_TRANSACTIONS	15	/* TCP Cookie Transactions */
#define TCP_THIN_LINEAR_TIMEOUTS 16      /* Use linear timeouts for thin streams*/
#define TCP_THIN_DUPACK         17      /* Fast retrans. after 1 dupack */
#define TCP_USER_TIMEOUT	18	/* How long for loss retry before timeout */
#define TCP_REPAIR		19	/* TCP sock is under repair right now */
#define TCP_REPAIR_QUEUE	20
#define TCP_QUEUE_SEQ		21
#define TCP_REPAIR_OPTIONS	22
#define TCP_FASTOPEN		23	/* Enable FastOpen on listeners */

struct tcp_repair_opt {
	__u32	opt_code;
	__u32	opt_val;
};

enum {
	TCP_NO_QUEUE,
	TCP_RECV_QUEUE,
	TCP_SEND_QUEUE,
	TCP_QUEUES_NR,
};

/* for TCP_INFO socket option */
#define TCPI_OPT_TIMESTAMPS	1
#define TCPI_OPT_SACK		2
#define TCPI_OPT_WSCALE		4
#define TCPI_OPT_ECN		8 /* ECN was negociated at TCP session init */
#define TCPI_OPT_ECN_SEEN	16 /* we received at least one packet with ECT */

enum tcp_ca_state {
	TCP_CA_Open = 0,
#define TCPF_CA_Open	(1<<TCP_CA_Open)
	TCP_CA_Disorder = 1,
#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
	TCP_CA_CWR = 2,
#define TCPF_CA_CWR	(1<<TCP_CA_CWR)
	TCP_CA_Recovery = 3,
#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
	TCP_CA_Loss = 4
#define TCPF_CA_Loss	(1<<TCP_CA_Loss)
};

struct tcp_info {
	__u8	tcpi_state;
	__u8	tcpi_ca_state;
	__u8	tcpi_retransmits;
	__u8	tcpi_probes;
	__u8	tcpi_backoff;
	__u8	tcpi_options;
	__u8	tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;

	__u32	tcpi_rto;
	__u32	tcpi_ato;
	__u32	tcpi_snd_mss;
	__u32	tcpi_rcv_mss;

	__u32	tcpi_unacked;
	__u32	tcpi_sacked;
	__u32	tcpi_lost;
	__u32	tcpi_retrans;
	__u32	tcpi_fackets;

	/* Times. */
	__u32	tcpi_last_data_sent;
	__u32	tcpi_last_ack_sent;     /* Not remembered, sorry. */
	__u32	tcpi_last_data_recv;
	__u32	tcpi_last_ack_recv;

	/* Metrics. */
	__u32	tcpi_pmtu;
	__u32	tcpi_rcv_ssthresh;
	__u32	tcpi_rtt;
	__u32	tcpi_rttvar;
	__u32	tcpi_snd_ssthresh;
	__u32	tcpi_snd_cwnd;
	__u32	tcpi_advmss;
	__u32	tcpi_reordering;

	__u32	tcpi_rcv_rtt;
	__u32	tcpi_rcv_space;

	__u32	tcpi_total_retrans;
};

/* for TCP_MD5SIG socket option */
#define TCP_MD5SIG_MAXKEYLEN	80

struct tcp_md5sig {
	struct __kernel_sockaddr_storage tcpm_addr;	/* address associated */
	__u16	__tcpm_pad1;				/* zero */
	__u16	tcpm_keylen;				/* key length */
	__u32	__tcpm_pad2;				/* zero */
	__u8	tcpm_key[TCP_MD5SIG_MAXKEYLEN];		/* key (binary) */
};

/* for TCP_COOKIE_TRANSACTIONS (TCPCT) socket option */
#define TCP_COOKIE_MIN		 8		/*  64-bits */
#define TCP_COOKIE_MAX		16		/* 128-bits */
#define TCP_COOKIE_PAIR_SIZE	(2*TCP_COOKIE_MAX)

/* Flags for both getsockopt and setsockopt */
#define TCP_COOKIE_IN_ALWAYS	(1 << 0)	/* Discard SYN without cookie */
#define TCP_COOKIE_OUT_NEVER	(1 << 1)	/* Prohibit outgoing cookies,
						 * supercedes everything. */

/* Flags for getsockopt */
#define TCP_S_DATA_IN		(1 << 2)	/* Was data received? */
#define TCP_S_DATA_OUT		(1 << 3)	/* Was data sent? */

/* TCP_COOKIE_TRANSACTIONS data */
struct tcp_cookie_transactions {
	__u16	tcpct_flags;			/* see above */
	__u8	__tcpct_pad1;			/* zero */
	__u8	tcpct_cookie_desired;		/* bytes */
	__u16	tcpct_s_data_desired;		/* bytes of variable data */
	__u16	tcpct_used;			/* bytes in value */
	__u8	tcpct_value[TCP_MSS_DEFAULT];
};

#ifdef __KERNEL__

#include <linux/skbuff.h>
#include <linux/dmaengine.h>
#include <net/sock.h>
#include <net/inet_connection_sock.h>
#include <net/inet_timewait_sock.h>

static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb)
{
	return (struct tcphdr *)skb_transport_header(skb);
}

static inline unsigned int tcp_hdrlen(const struct sk_buff *skb)
{
	return tcp_hdr(skb)->doff * 4;
}

static inline unsigned int tcp_optlen(const struct sk_buff *skb)
{
	return (tcp_hdr(skb)->doff - 5) * 4;
}

/* TCP Fast Open */
#define TCP_FASTOPEN_COOKIE_MIN	4	/* Min Fast Open Cookie size in bytes */
#define TCP_FASTOPEN_COOKIE_MAX	16	/* Max Fast Open Cookie size in bytes */
#define TCP_FASTOPEN_COOKIE_SIZE 8	/* the size employed by this impl. */

/* TCP Fast Open Cookie as stored in memory */
struct tcp_fastopen_cookie {
	s8	len;
	u8	val[TCP_FASTOPEN_COOKIE_MAX];
};

/* This defines a selective acknowledgement block. */
struct tcp_sack_block_wire {
	__be32	start_seq;
	__be32	end_seq;
};

struct tcp_sack_block {
	u32	start_seq;
	u32	end_seq;
};

/*These are used to set the sack_ok field in struct tcp_options_received */
#define TCP_SACK_SEEN     (1 << 0)   /*1 = peer is SACK capable, */
#define TCP_FACK_ENABLED  (1 << 1)   /*1 = FACK is enabled locally*/
#define TCP_DSACK_SEEN    (1 << 2)   /*1 = DSACK was received from peer*/

struct tcp_options_received {
/*	PAWS/RTTM data	*/
	long	ts_recent_stamp;/* Time we stored ts_recent (for aging) */
	u32	ts_recent;	/* Time stamp to echo next		*/
	u32	rcv_tsval;	/* Time stamp value             	*/
	u32	rcv_tsecr;	/* Time stamp echo reply        	*/
	u16 	saw_tstamp : 1,	/* Saw TIMESTAMP on last packet		*/
		tstamp_ok : 1,	/* TIMESTAMP seen on SYN packet		*/
		dsack : 1,	/* D-SACK is scheduled			*/
		wscale_ok : 1,	/* Wscale seen on SYN packet		*/
		sack_ok : 4,	/* SACK seen on SYN packet		*/
		snd_wscale : 4,	/* Window scaling received from sender	*/
		rcv_wscale : 4;	/* Window scaling to send to receiver	*/
	u8	cookie_plus:6,	/* bytes in authenticator/cookie option	*/
		cookie_out_never:1,
		cookie_in_always:1;
	u8	num_sacks;	/* Number of SACK blocks		*/
	u16	user_mss;	/* mss requested by user in ioctl	*/
	u16	mss_clamp;	/* Maximal mss, negotiated at connection setup */
};

static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
{
	rx_opt->tstamp_ok = rx_opt->sack_ok = 0;
	rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
	rx_opt->cookie_plus = 0;
}

/* This is the max number of SACKS that we'll generate and process. It's safe
 * to increase this, although since:
 *   size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8)
 * only four options will fit in a standard TCP header */
#define TCP_NUM_SACKS 4

struct tcp_cookie_values;
struct tcp_request_sock_ops;

struct tcp_request_sock {
	struct inet_request_sock 	req;
#ifdef CONFIG_TCP_MD5SIG
	/* Only used by TCP MD5 Signature so far. */
	const struct tcp_request_sock_ops *af_specific;
#endif
	struct sock			*listener; /* needed for TFO */
	u32				rcv_isn;
	u32				snt_isn;
	u32				snt_synack; /* synack sent time */
	u32				rcv_nxt; /* the ack # by SYNACK. For
						  * FastOpen it's the seq#
						  * after data-in-SYN.
						  */
};

static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
{
	return (struct tcp_request_sock *)req;
}

struct tcp_sock {
	/* inet_connection_sock has to be the first member of tcp_sock */
	struct inet_connection_sock	inet_conn;
	u16	tcp_header_len;	/* Bytes of tcp header to send		*/
	u16	xmit_size_goal_segs; /* Goal for segmenting output packets */

/*
 *	Header prediction flags
 *	0x5?10 << 16 + snd_wnd in net byte order
 */
	__be32	pred_flags;

/*
 *	RFC793 variables by their proper names. This means you can
 *	read the code and the spec side by side (and laugh ...)
 *	See RFC793 and RFC1122. The RFC writes these in capitals.
 */
 	u32	rcv_nxt;	/* What we want to receive next 	*/
	u32	copied_seq;	/* Head of yet unread data		*/
	u32	rcv_wup;	/* rcv_nxt on last window update sent	*/
 	u32	snd_nxt;	/* Next sequence we send		*/

 	u32	snd_una;	/* First byte we want an ack for	*/
 	u32	snd_sml;	/* Last byte of the most recently transmitted small packet */
	u32	rcv_tstamp;	/* timestamp of last received ACK (for keepalives) */
	u32	lsndtime;	/* timestamp of last sent data packet (for restart window) */

	struct list_head tsq_node; /* anchor in tsq_tasklet.head list */
	unsigned long	tsq_flags;

	/* Data for direct copy to user */
	struct {
		struct sk_buff_head	prequeue;
		struct task_struct	*task;
		struct iovec		*iov;
		int			memory;
		int			len;
#ifdef CONFIG_NET_DMA
		/* members for async copy */
		struct dma_chan		*dma_chan;
		int			wakeup;
		struct dma_pinned_list	*pinned_list;
		dma_cookie_t		dma_cookie;
#endif
	} ucopy;

	u32	snd_wl1;	/* Sequence for window update		*/
	u32	snd_wnd;	/* The window we expect to receive	*/
	u32	max_window;	/* Maximal window ever seen from peer	*/
	u32	mss_cache;	/* Cached effective mss, not including SACKS */

	u32	window_clamp;	/* Maximal window to advertise		*/
	u32	rcv_ssthresh;	/* Current window clamp			*/

	u32	frto_highmark;	/* snd_nxt when RTO occurred */
	u16	advmss;		/* Advertised MSS			*/
	u8	frto_counter;	/* Number of new acks after RTO */
	u8	nonagle     : 4,/* Disable Nagle algorithm?             */
		thin_lto    : 1,/* Use linear timeouts for thin streams */
		thin_dupack : 1,/* Fast retransmit on first dupack      */
		repair      : 1,
		unused      : 1;
	u8	repair_queue;
	u8	do_early_retrans:1,/* Enable RFC5827 early-retransmit  */
		early_retrans_delayed:1, /* Delayed ER timer installed */
		syn_data:1,	/* SYN includes data */
		syn_fastopen:1;	/* SYN includes Fast Open option */

/* RTT measurement */
	u32	srtt;		/* smoothed round trip time << 3	*/
	u32	mdev;		/* medium deviation			*/
	u32	mdev_max;	/* maximal mdev for the last rtt period	*/
	u32	rttvar;		/* smoothed mdev_max			*/
	u32	rtt_seq;	/* sequence number to update rttvar	*/

	u32	packets_out;	/* Packets which are "in flight"	*/
	u32	retrans_out;	/* Retransmitted packets out		*/

	u16	urg_data;	/* Saved octet of OOB data and control flags */
	u8	ecn_flags;	/* ECN status bits.			*/
	u8	reordering;	/* Packet reordering metric.		*/
	u32	snd_up;		/* Urgent pointer		*/

	u8	keepalive_probes; /* num of allowed keep alive probes	*/
/*
 *      Options received (usually on last packet, some only on SYN packets).
 */
	struct tcp_options_received rx_opt;

/*
 *	Slow start and congestion control (see also Nagle, and Karn & Partridge)
 */
 	u32	snd_ssthresh;	/* Slow start size threshold		*/
 	u32	snd_cwnd;	/* Sending congestion window		*/
	u32	snd_cwnd_cnt;	/* Linear increase counter		*/
	u32	snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
	u32	snd_cwnd_used;
	u32	snd_cwnd_stamp;
	u32	prior_cwnd;	/* Congestion window at start of Recovery. */
	u32	prr_delivered;	/* Number of newly delivered packets to
				 * receiver in Recovery. */
	u32	prr_out;	/* Total number of pkts sent during Recovery. */

 	u32	rcv_wnd;	/* Current receiver window		*/
	u32	write_seq;	/* Tail(+1) of data held in tcp send buffer */
	u32	pushed_seq;	/* Last pushed seq, required to talk to windows */
	u32	lost_out;	/* Lost packets			*/
	u32	sacked_out;	/* SACK'd packets			*/
	u32	fackets_out;	/* FACK'd packets			*/
	u32	tso_deferred;
	u32	bytes_acked;	/* Appropriate Byte Counting - RFC3465 */

	/* from STCP, retrans queue hinting */
	struct sk_buff* lost_skb_hint;
	struct sk_buff *scoreboard_skb_hint;
	struct sk_buff *retransmit_skb_hint;

	struct sk_buff_head	out_of_order_queue; /* Out of order segments go here */

	/* SACKs data, these 2 need to be together (see tcp_options_write) */
	struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
	struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/

	struct tcp_sack_block recv_sack_cache[4];

	struct sk_buff *highest_sack;   /* skb just after the highest
					 * skb with SACKed bit set
					 * (validity guaranteed only if
					 * sacked_out > 0)
					 */

	int     lost_cnt_hint;
	u32     retransmit_high;	/* L-bits may be on up to this seqno */

	u32	lost_retrans_low;	/* Sent seq after any rxmit (lowest) */

	u32	prior_ssthresh; /* ssthresh saved at recovery start	*/
	u32	high_seq;	/* snd_nxt at onset of congestion	*/

	u32	retrans_stamp;	/* Timestamp of the last retransmit,
				 * also used in SYN-SENT to remember stamp of
				 * the first SYN. */
	u32	undo_marker;	/* tracking retrans started here. */
	int	undo_retrans;	/* number of undoable retransmissions. */
	u32	total_retrans;	/* Total retransmits for entire connection */

	u32	urg_seq;	/* Seq of received urgent pointer */
	unsigned int		keepalive_time;	  /* time before keep alive takes place */
	unsigned int		keepalive_intvl;  /* time interval between keep alive probes */

	int			linger2;

/* Receiver side RTT estimation */
	struct {
		u32	rtt;
		u32	seq;
		u32	time;
	} rcv_rtt_est;

/* Receiver queue space */
	struct {
		int	space;
		u32	seq;
		u32	time;
	} rcvq_space;

/* TCP-specific MTU probe information. */
	struct {
		u32		  probe_seq_start;
		u32		  probe_seq_end;
	} mtu_probe;
	u32	mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG
			   * while socket was owned by user.
			   */

#ifdef CONFIG_TCP_MD5SIG
/* TCP AF-Specific parts; only used by MD5 Signature support so far */
	const struct tcp_sock_af_ops	*af_specific;

/* TCP MD5 Signature Option information */
	struct tcp_md5sig_info	__rcu *md5sig_info;
#endif

	/* When the cookie options are generated and exchanged, then this
	 * object holds a reference to them (cookie_values->kref).  Also
	 * contains related tcp_cookie_transactions fields.
	 */
	struct tcp_cookie_values  *cookie_values;

/* TCP fastopen related information */
	struct tcp_fastopen_request *fastopen_req;
	/* fastopen_rsk points to request_sock that resulted in this big
	 * socket. Used to retransmit SYNACKs etc.
	 */
	struct request_sock *fastopen_rsk;
};

enum tsq_flags {
	TSQ_THROTTLED,
	TSQ_QUEUED,
	TCP_TSQ_DEFERRED,	   /* tcp_tasklet_func() found socket was owned */
	TCP_WRITE_TIMER_DEFERRED,  /* tcp_write_timer() found socket was owned */
	TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */
	TCP_MTU_REDUCED_DEFERRED,  /* tcp_v{4|6}_err() could not call
				    * tcp_v{4|6}_mtu_reduced()
				    */
};

static inline struct tcp_sock *tcp_sk(const struct sock *sk)
{
	return (struct tcp_sock *)sk;
}

struct tcp_timewait_sock {
	struct inet_timewait_sock tw_sk;
	u32			  tw_rcv_nxt;
	u32			  tw_snd_nxt;
	u32			  tw_rcv_wnd;
	u32			  tw_ts_recent;
	long			  tw_ts_recent_stamp;
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key	  *tw_md5_key;
#endif
	/* Few sockets in timewait have cookies; in that case, then this
	 * object holds a reference to them (tw_cookie_values->kref).
	 */
	struct tcp_cookie_values  *tw_cookie_values;
};

static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
{
	return (struct tcp_timewait_sock *)sk;
}

static inline bool tcp_passive_fastopen(const struct sock *sk)
{
	return (sk->sk_state == TCP_SYN_RECV &&
		tcp_sk(sk)->fastopen_rsk != NULL);
}

static inline bool fastopen_cookie_present(struct tcp_fastopen_cookie *foc)
{
	return foc->len != -1;
}

extern void tcp_sock_destruct(struct sock *sk);

static inline int fastopen_init_queue(struct sock *sk, int backlog)
{
	struct request_sock_queue *queue =
	    &inet_csk(sk)->icsk_accept_queue;

	if (queue->fastopenq == NULL) {
		queue->fastopenq = kzalloc(
		    sizeof(struct fastopen_queue),
		    sk->sk_allocation);
		if (queue->fastopenq == NULL)
			return -ENOMEM;

		sk->sk_destruct = tcp_sock_destruct;
		spin_lock_init(&queue->fastopenq->lock);
	}
	queue->fastopenq->max_qlen = backlog;
	return 0;
}

#endif	/* __KERNEL__ */

#endif	/* _LINUX_TCP_H */
OpenPOWER on IntegriCloud