xref: /titanic_50/usr/src/uts/common/inet/tcp.h (revision c9a6ea2e938727c95af7108c5e00eee4c890c7ae)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
23  */
24 /* Copyright (c) 1990 Mentat Inc. */
25 
26 #ifndef	_INET_TCP_H
27 #define	_INET_TCP_H
28 
29 #ifdef	__cplusplus
30 extern "C" {
31 #endif
32 
33 #include <sys/inttypes.h>
34 #include <netinet/ip6.h>
35 #include <netinet/tcp.h>
36 #include <sys/socket.h>
37 #include <sys/socket_proto.h>
38 #include <sys/md5.h>
39 #include <inet/common.h>
40 #include <inet/ip.h>
41 #include <inet/ip6.h>
42 #include <inet/mi.h>
43 #include <inet/mib2.h>
44 #include <inet/tcp_stack.h>
45 #include <inet/tcp_sack.h>
46 
47 /* TCP states */
48 #define	TCPS_CLOSED		-6
49 #define	TCPS_IDLE		-5	/* idle (opened, but not bound) */
50 #define	TCPS_BOUND		-4	/* bound, ready to connect or accept */
51 #define	TCPS_LISTEN		-3	/* listening for connection */
52 #define	TCPS_SYN_SENT		-2	/* active, have sent syn */
53 #define	TCPS_SYN_RCVD		-1	/* have received syn (and sent ours) */
54 /* states < TCPS_ESTABLISHED are those where connections not established */
55 #define	TCPS_ESTABLISHED	0	/* established */
56 #define	TCPS_CLOSE_WAIT		1	/* rcvd fin, waiting for close */
57 /* states > TCPS_CLOSE_WAIT are those where user has closed */
58 #define	TCPS_FIN_WAIT_1		2	/* have closed and sent fin */
59 #define	TCPS_CLOSING		3	/* closed, xchd FIN, await FIN ACK */
60 #define	TCPS_LAST_ACK		4	/* had fin and close; await FIN ACK */
61 /* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
62 #define	TCPS_FIN_WAIT_2		5	/* have closed, fin is acked */
63 #define	TCPS_TIME_WAIT		6	/* in 2*msl quiet wait after close */
64 
65 /*
66  * Internal flags used in conjunction with the packet header flags.
67  * Used in tcp_input_data to keep track of what needs to be done.
68  */
69 #define	TH_LIMIT_XMIT		0x0400	/* Limited xmit is needed */
70 #define	TH_XMIT_NEEDED		0x0800	/* Window opened - send queued data */
71 #define	TH_REXMIT_NEEDED	0x1000	/* Time expired for unacked data */
72 #define	TH_ACK_NEEDED		0x2000	/* Send an ack now. */
73 #define	TH_NEED_SACK_REXMIT	0x4000	/* Use SACK info to retransmission */
74 #define	TH_ACK_TIMER_NEEDED	0x8000	/* Start the delayed ACK timer */
75 #define	TH_ORDREL_NEEDED	0x10000	/* Generate an ordrel indication */
76 #define	TH_MARKNEXT_NEEDED	0x20000	/* Data should have MSGMARKNEXT */
77 #define	TH_SEND_URP_MARK	0x40000	/* Send up tcp_urp_mark_mp */
78 
79 /*
80  * TCP sequence numbers are 32 bit integers operated
81  * on with modular arithmetic.  These macros can be
82  * used to compare such integers.
83  */
84 #define	SEQ_LT(a, b)	((int32_t)((a)-(b)) < 0)
85 #define	SEQ_LEQ(a, b)	((int32_t)((a)-(b)) <= 0)
86 #define	SEQ_GT(a, b)	((int32_t)((a)-(b)) > 0)
87 #define	SEQ_GEQ(a, b)	((int32_t)((a)-(b)) >= 0)
88 
89 /* TCP Protocol header */
90 typedef	struct tcphdr_s {
91 	uint8_t		th_lport[2];	/* Source port */
92 	uint8_t		th_fport[2];	/* Destination port */
93 	uint8_t		th_seq[4];	/* Sequence number */
94 	uint8_t		th_ack[4];	/* Acknowledgement number */
95 	uint8_t		th_offset_and_rsrvd[1]; /* Offset to the packet data */
96 	uint8_t		th_flags[1];
97 	uint8_t		th_win[2];	/* Allocation number */
98 	uint8_t		th_sum[2];	/* TCP checksum */
99 	uint8_t		th_urp[2];	/* Urgent pointer */
100 } tcph_t;
101 
102 #define	TCP_HDR_LENGTH(tcph) \
103 	((((tcph_t *)tcph)->th_offset_and_rsrvd[0] >>2) &(0xF << 2))
104 #define	TCP_MAX_COMBINED_HEADER_LENGTH	(60 + 60) /* Maxed out ip + tcp */
105 #define	TCP_MAX_IP_OPTIONS_LENGTH	(60 - IP_SIMPLE_HDR_LENGTH)
106 #define	TCP_MAX_HDR_LENGTH		60
107 #define	TCP_MAX_TCP_OPTIONS_LENGTH	(60 - sizeof (tcpha_t))
108 #define	TCP_MIN_HEADER_LENGTH		20
109 #define	TCP_MAXWIN			65535
110 #define	TCP_PORT_LEN			sizeof (in_port_t)
111 #define	TCP_MAX_WINSHIFT		14
112 #define	TCP_MAX_LARGEWIN		(TCP_MAXWIN << TCP_MAX_WINSHIFT)
113 #define	TCP_MAX_LSO_LENGTH	(IP_MAXPACKET - TCP_MAX_COMBINED_HEADER_LENGTH)
114 
115 #define	TCPIP_HDR_LENGTH(mp, n)					\
116 	(n) = IPH_HDR_LENGTH((mp)->b_rptr),			\
117 	(n) += TCP_HDR_LENGTH((tcpha_t *)&(mp)->b_rptr[(n)])
118 
119 /* TCP Protocol header (used if the header is known to be 32-bit aligned) */
120 typedef	struct tcphdra_s {
121 	in_port_t	tha_lport;	/* Source port */
122 	in_port_t	tha_fport;	/* Destination port */
123 	uint32_t	tha_seq;	/* Sequence number */
124 	uint32_t	tha_ack;	/* Acknowledgement number */
125 	uint8_t tha_offset_and_reserved; /* Offset to the packet data */
126 	uint8_t		tha_flags;
127 	uint16_t	tha_win;	/* Allocation number */
128 	uint16_t	tha_sum;	/* TCP checksum */
129 	uint16_t	tha_urp;	/* Urgent pointer */
130 } tcpha_t;
131 
132 struct conn_s;
133 struct tcp_listen_cnt_s;
134 
135 /*
136  * Control structure for each open TCP stream,
137  * defined only within the kernel or for a kmem user.
138  * NOTE: tcp_reinit_values MUST have a line for each field in this structure!
139  */
140 #if (defined(_KERNEL) || defined(_KMEMUSER))
141 
142 typedef struct tcp_s {
143 	struct tcp_s	*tcp_time_wait_next;
144 				/* Pointer to next T/W block */
145 	struct tcp_s	*tcp_time_wait_prev;
146 				/* Pointer to previous T/W next */
147 	int64_t		tcp_time_wait_expire;
148 
149 	struct conn_s	*tcp_connp;	/* back pointer to conn_t */
150 	tcp_stack_t	*tcp_tcps;	/* back pointer to tcp_stack_t */
151 
152 	int32_t	tcp_state;
153 	int32_t	tcp_rcv_ws;		/* My window scale power */
154 	int32_t	tcp_snd_ws;		/* Sender's window scale power */
155 	uint32_t tcp_ts_recent;		/* Timestamp of earliest unacked */
156 					/*  data segment */
157 	clock_t	tcp_rto;		/* Round trip timeout */
158 	int64_t	tcp_last_rcv_lbolt;
159 				/* lbolt on last packet, used for PAWS */
160 	uint32_t tcp_rto_initial;	/* Initial RTO */
161 	uint32_t tcp_rto_min;		/* Minimum RTO */
162 	uint32_t tcp_rto_max;		/* Maximum RTO */
163 
164 	uint32_t tcp_snxt;		/* Senders next seq num */
165 	uint32_t tcp_swnd;		/* Senders window (relative to suna) */
166 	uint32_t tcp_mss;		/* Max segment size */
167 	uint32_t tcp_iss;		/* Initial send seq num */
168 	uint32_t tcp_rnxt;		/* Seq we expect to recv next */
169 	uint32_t tcp_rwnd;
170 
171 	/* Fields arranged in approximate access order along main paths */
172 	mblk_t	*tcp_xmit_head;		/* Head of xmit/rexmit list */
173 	mblk_t	*tcp_xmit_last;		/* Last valid data seen by tcp_wput */
174 	mblk_t	*tcp_xmit_tail;		/* Last data sent */
175 	uint32_t tcp_unsent;		/* # of bytes in hand that are unsent */
176 	uint32_t tcp_xmit_tail_unsent;	/* # of unsent bytes in xmit_tail */
177 
178 	uint32_t tcp_suna;		/* Sender unacknowledged */
179 	uint32_t tcp_rexmit_nxt;	/* Next rexmit seq num */
180 	uint32_t tcp_rexmit_max;	/* Max retran seq num */
181 	int32_t	tcp_snd_burst;		/* Send burst factor */
182 	uint32_t tcp_cwnd;		/* Congestion window */
183 	int32_t tcp_cwnd_cnt;		/* cwnd cnt in congestion avoidance */
184 
185 	uint32_t tcp_ibsegs;		/* Inbound segments on this stream */
186 	uint32_t tcp_obsegs;		/* Outbound segments on this stream */
187 
188 	uint32_t tcp_naglim;		/* Tunable nagle limit */
189 	uint32_t	tcp_valid_bits;
190 #define	TCP_ISS_VALID	0x1	/* Is the tcp_iss seq num active? */
191 #define	TCP_FSS_VALID	0x2	/* Is the tcp_fss seq num active? */
192 #define	TCP_URG_VALID	0x4	/* Is the tcp_urg seq num active? */
193 #define	TCP_OFO_FIN_VALID 0x8	/* Has TCP received an out of order FIN? */
194 
195 
196 
197 	timeout_id_t	tcp_timer_tid;	/* Control block for timer service */
198 	uchar_t	tcp_timer_backoff;	/* Backoff shift count. */
199 	int64_t tcp_last_recv_time;	/* Last time we receive a segment. */
200 	uint32_t tcp_init_cwnd;		/* Initial cwnd (start/restart) */
201 
202 	/* Following manipulated by TCP under squeue protection */
203 	uint32_t
204 		tcp_urp_last_valid : 1,	/* Is tcp_urp_last valid? */
205 		tcp_hard_binding : 1,	/* TCP_DETACHED_NONEAGER */
206 		tcp_fin_acked : 1,	/* Has our FIN been acked? */
207 		tcp_fin_rcvd : 1,	/* Have we seen a FIN? */
208 
209 		tcp_fin_sent : 1,	/* Have we sent our FIN yet? */
210 		tcp_ordrel_done : 1,	/* Have we sent the ord_rel upstream? */
211 		tcp_detached : 1,	/* If we're detached from a stream */
212 		tcp_zero_win_probe: 1,	/* Zero win probing is in progress */
213 
214 		tcp_loopback: 1,	/* src and dst are the same machine */
215 		tcp_localnet: 1,	/* src and dst are on the same subnet */
216 		tcp_syn_defense: 1,	/* For defense against SYN attack */
217 #define	tcp_dontdrop	tcp_syn_defense
218 		tcp_set_timer : 1,
219 
220 		tcp_active_open: 1,	/* This is a active open */
221 		tcp_rexmit : 1,		/* TCP is retransmitting */
222 		tcp_snd_sack_ok : 1,	/* Can use SACK for this connection */
223 		tcp_hwcksum : 1,	/* The NIC is capable of hwcksum */
224 
225 		tcp_ip_forward_progress : 1,
226 		tcp_ecn_ok : 1,		/* Can use ECN for this connection */
227 		tcp_ecn_echo_on : 1,	/* Need to do ECN echo */
228 		tcp_ecn_cwr_sent : 1,	/* ECN_CWR has been sent */
229 
230 		tcp_cwr : 1,		/* Cwnd has reduced recently */
231 
232 		tcp_pad_to_bit31 : 11;
233 
234 	/* Following manipulated by TCP under squeue protection */
235 	uint32_t
236 		tcp_snd_ts_ok  : 1,
237 		tcp_snd_ws_ok  : 1,
238 		tcp_reserved_port : 1,
239 		tcp_in_free_list : 1,
240 
241 		tcp_snd_zcopy_on : 1,	/* xmit zero-copy enabled */
242 		tcp_snd_zcopy_aware : 1, /* client is zero-copy aware */
243 		tcp_xmit_zc_clean : 1,	/* the xmit list is free of zc-mblk */
244 		tcp_wait_for_eagers : 1, /* Wait for eagers to disappear */
245 
246 		tcp_accept_error : 1,	/* Error during TLI accept */
247 		tcp_send_discon_ind : 1, /* TLI accept err, send discon ind */
248 		tcp_cork : 1,		/* tcp_cork option */
249 		tcp_tconnind_started : 1, /* conn_ind message is being sent */
250 
251 		tcp_lso :1,		/* Lower layer is capable of LSO */
252 		tcp_is_wnd_shrnk : 1,	/* Window has shrunk */
253 
254 		tcp_pad_to_bit_31 : 18;
255 
256 	uint32_t	tcp_initial_pmtu; /* Initial outgoing Path MTU. */
257 
258 	mblk_t	*tcp_reass_head;	/* Out of order reassembly list head */
259 	mblk_t	*tcp_reass_tail;	/* Out of order reassembly list tail */
260 
261 	/* SACK related info */
262 	tcp_sack_info_t	tcp_sack_info;
263 
264 #define	tcp_pipe		tcp_sack_info.tcp_pipe
265 #define	tcp_fack		tcp_sack_info.tcp_fack
266 #define	tcp_sack_snxt		tcp_sack_info.tcp_sack_snxt
267 #define	tcp_max_sack_blk	tcp_sack_info.tcp_max_sack_blk
268 #define	tcp_num_sack_blk	tcp_sack_info.tcp_num_sack_blk
269 #define	tcp_sack_list		tcp_sack_info.tcp_sack_list
270 #define	tcp_num_notsack_blk	tcp_sack_info.tcp_num_notsack_blk
271 #define	tcp_cnt_notsack_list	tcp_sack_info.tcp_cnt_notsack_list
272 #define	tcp_notsack_list	tcp_sack_info.tcp_notsack_list
273 
274 	mblk_t	*tcp_rcv_list;		/* Queued until push, urgent data, */
275 	mblk_t	*tcp_rcv_last_head;	/* optdata, or the count exceeds */
276 	mblk_t	*tcp_rcv_last_tail;	/* tcp_rcv_push_wait. */
277 	uint32_t tcp_rcv_cnt;		/* tcp_rcv_list is b_next chain. */
278 
279 	uint32_t tcp_cwnd_ssthresh;	/* Congestion window */
280 	uint32_t tcp_cwnd_max;
281 	uint32_t tcp_csuna;		/* Clear (no rexmits in window) suna */
282 
283 	clock_t	tcp_rtt_sa;		/* Round trip smoothed average */
284 	clock_t	tcp_rtt_sd;		/* Round trip smoothed deviation */
285 	clock_t	tcp_rtt_update;		/* Round trip update(s) */
286 	clock_t tcp_ms_we_have_waited;	/* Total retrans time */
287 
288 	uint32_t tcp_swl1;		/* These help us avoid using stale */
289 	uint32_t tcp_swl2;		/*  packets to update state */
290 
291 	uint32_t tcp_rack;		/* Seq # we have acked */
292 	uint32_t tcp_rack_cnt;		/* # of segs we have deferred ack */
293 	uint32_t tcp_rack_cur_max;	/* # of segs we may defer ack for now */
294 	uint32_t tcp_rack_abs_max;	/* # of segs we may defer ack ever */
295 	timeout_id_t	tcp_ack_tid;	/* Delayed ACK timer ID */
296 	timeout_id_t	tcp_push_tid;	/* Push timer ID */
297 
298 	uint32_t tcp_max_swnd;		/* Maximum swnd we have seen */
299 
300 	struct tcp_s *tcp_listener;	/* Our listener */
301 
302 	uint32_t tcp_irs;		/* Initial recv seq num */
303 	uint32_t tcp_fss;		/* Final/fin send seq num */
304 	uint32_t tcp_urg;		/* Urgent data seq num */
305 
306 	clock_t	tcp_first_timer_threshold;  /* When to prod IP */
307 	clock_t	tcp_second_timer_threshold; /* When to give up completely */
308 	clock_t	tcp_first_ctimer_threshold; /* 1st threshold while connecting */
309 	clock_t tcp_second_ctimer_threshold; /* 2nd ... while connecting */
310 
311 	uint32_t tcp_urp_last;		/* Last urp for which signal sent */
312 	mblk_t	*tcp_urp_mp;		/* T_EXDATA_IND for urgent byte */
313 	mblk_t	*tcp_urp_mark_mp;	/* zero-length marked/unmarked msg */
314 
315 	int tcp_conn_req_cnt_q0;	/* # of conn reqs in SYN_RCVD */
316 	int tcp_conn_req_cnt_q;	/* # of conn reqs in ESTABLISHED */
317 	int tcp_conn_req_max;	/* # of ESTABLISHED conn reqs allowed */
318 	t_scalar_t tcp_conn_req_seqnum;	/* Incrementing pending conn req ID */
319 #define	tcp_ip_addr_cache	tcp_reass_tail
320 					/* Cache ip addresses that */
321 					/* complete the 3-way handshake */
322 	kmutex_t  tcp_eager_lock;
323 	struct tcp_s *tcp_eager_next_q; /* next eager in ESTABLISHED state */
324 	struct tcp_s *tcp_eager_last_q;	/* last eager in ESTABLISHED state */
325 	struct tcp_s *tcp_eager_next_q0; /* next eager in SYN_RCVD state */
326 	struct tcp_s *tcp_eager_prev_q0; /* prev eager in SYN_RCVD state */
327 					/* all eagers form a circular list */
328 	boolean_t tcp_conn_def_q0;	/* move from q0 to q deferred */
329 
330 	union {
331 	    mblk_t *tcp_eager_conn_ind; /* T_CONN_IND waiting for 3rd ack. */
332 	    mblk_t *tcp_opts_conn_req; /* T_CONN_REQ w/ options processed */
333 	} tcp_conn;
334 	uint32_t tcp_syn_rcvd_timeout;	/* How many SYN_RCVD timeout in q0 */
335 
336 	/* TCP Keepalive Timer members */
337 	int32_t	tcp_ka_last_intrvl;	/* Last probe interval */
338 	timeout_id_t tcp_ka_tid;	/* Keepalive timer ID */
339 	uint32_t tcp_ka_interval;	/* Keepalive interval */
340 	uint32_t tcp_ka_abort_thres;	/* Keepalive abort threshold */
341 
342 	int32_t	tcp_client_errno;	/* How the client screwed up */
343 
344 	/*
345 	 * The header template lives in conn_ht_iphc allocated by tcp_build_hdrs
346 	 * We maintain three pointers into conn_ht_iphc.
347 	 */
348 	ipha_t	*tcp_ipha;		/* IPv4 header in conn_ht_iphc */
349 	ip6_t	*tcp_ip6h;		/* IPv6 header in conn_ht_iphc */
350 	tcpha_t	*tcp_tcpha;		/* TCP header in conn_ht_iphc */
351 
352 	uint16_t tcp_last_sent_len;	/* Record length for nagle */
353 	uint16_t tcp_last_recv_len;	/* Used by DTrace */
354 	uint16_t tcp_dupack_cnt;	/* # of consequtive duplicate acks */
355 
356 	kmutex_t	*tcp_acceptor_lockp;	/* Ptr to tf_lock */
357 
358 	mblk_t		*tcp_ordrel_mp;		/* T_ordrel_ind mblk */
359 	t_uscalar_t	tcp_acceptor_id;	/* ACCEPTOR_id */
360 
361 	int		tcp_ipsec_overhead;
362 
363 	uint_t		tcp_recvifindex; /* Last received IPV6_RCVPKTINFO */
364 	uint_t		tcp_recvhops;	/* Last received IPV6_RECVHOPLIMIT */
365 	uint_t		tcp_recvtclass;	/* Last received IPV6_RECVTCLASS */
366 	ip6_hbh_t	*tcp_hopopts;	/* Last received IPV6_RECVHOPOPTS */
367 	ip6_dest_t	*tcp_dstopts;	/* Last received IPV6_RECVDSTOPTS */
368 	ip6_dest_t	*tcp_rthdrdstopts; /* Last recv IPV6_RECVRTHDRDSTOPTS */
369 	ip6_rthdr_t	*tcp_rthdr;	/* Last received IPV6_RECVRTHDR */
370 	uint_t		tcp_hopoptslen;
371 	uint_t		tcp_dstoptslen;
372 	uint_t		tcp_rthdrdstoptslen;
373 	uint_t		tcp_rthdrlen;
374 
375 	mblk_t		*tcp_timercache;
376 
377 	kmutex_t	tcp_closelock;
378 	kcondvar_t	tcp_closecv;
379 	uint8_t		tcp_closed;
380 	uint8_t		tcp_closeflags;
381 	mblk_t		tcp_closemp;
382 	timeout_id_t	tcp_linger_tid;	/* Linger timer ID */
383 
384 	struct tcp_s *tcp_acceptor_hash; /* Acceptor hash chain */
385 	struct tcp_s **tcp_ptpahn; /* Pointer to previous accept hash next. */
386 	struct tcp_s *tcp_bind_hash; /* Bind hash chain */
387 	struct tcp_s *tcp_bind_hash_port; /* tcp_t's bound to the same lport */
388 	struct tcp_s **tcp_ptpbhn;
389 
390 	uint_t		tcp_maxpsz_multiplier;
391 
392 	uint32_t	tcp_lso_max; /* maximum LSO payload */
393 
394 	uint32_t	tcp_ofo_fin_seq; /* Recv out of order FIN seq num */
395 	uint32_t	tcp_cwr_snd_max;
396 
397 	struct tcp_s *tcp_saved_listener;	/* saved value of listener */
398 
399 	uint32_t	tcp_in_ack_unsent;	/* ACK for unsent data cnt. */
400 
401 	/*
402 	 * All fusion-related fields are protected by squeue.
403 	 */
404 	struct tcp_s *tcp_loopback_peer;	/* peer tcp for loopback */
405 	mblk_t	*tcp_fused_sigurg_mp;		/* M_PCSIG mblk for SIGURG */
406 
407 	uint32_t
408 		tcp_fused : 1,		/* loopback tcp in fusion mode */
409 		tcp_unfusable : 1,	/* fusion not allowed on endpoint */
410 		tcp_fused_sigurg : 1,	/* send SIGURG upon draining */
411 
412 		tcp_fuse_to_bit_31 : 29;
413 
414 	kmutex_t tcp_non_sq_lock;
415 
416 	/*
417 	 * This variable is accessed without any lock protection
418 	 * and therefore must not be declared as a bit field along
419 	 * with the rest which require such condition.
420 	 */
421 	boolean_t	tcp_issocket;	/* this is a socket tcp */
422 
423 	/* protected by the tcp_non_sq_lock lock */
424 	uint32_t	tcp_squeue_bytes;
425 
426 	/*
427 	 * tcp_closemp_used is protected by listener's tcp_eager_lock
428 	 * when used for eagers. When used for a tcp in TIME_WAIT state
429 	 * or in tcp_close(), it is not protected by any lock as we
430 	 * do not expect any other thread to use it concurrently.
431 	 * We do allow re-use of tcp_closemp in tcp_time_wait_collector()
432 	 * and tcp_close() but not concurrently.
433 	 */
434 	boolean_t tcp_closemp_used;
435 
436 	/*
437 	 * previous and next eagers in the list of droppable eagers. See
438 	 * the comments before MAKE_DROPPABLE(). These pointers are
439 	 * protected by listener's tcp_eager_lock.
440 	 */
441 	struct tcp_s	*tcp_eager_prev_drop_q0;
442 	struct tcp_s	*tcp_eager_next_drop_q0;
443 
444 	/*
445 	 * Have we flow controlled xmitter?
446 	 * This variable can be modified outside the squeue and hence must
447 	 * not be declared as a bit field along with the rest that are
448 	 * modified only within the squeue.
449 	 * protected by the tcp_non_sq_lock lock.
450 	 */
451 	boolean_t	tcp_flow_stopped;
452 
453 	/*
454 	 * Sender's next sequence number at the time the window was shrunk.
455 	 */
456 	uint32_t	tcp_snxt_shrunk;
457 
458 	/*
459 	 * Socket generation number which is bumped when a connection attempt
460 	 * is initiated. Its main purpose is to ensure that the socket does not
461 	 * miss the asynchronous connected/disconnected notification.
462 	 */
463 	sock_connid_t	tcp_connid;
464 
465 	/* mblk_t used to enter TCP's squeue from the service routine. */
466 	mblk_t		*tcp_rsrv_mp;
467 	/* Mutex for accessing tcp_rsrv_mp */
468 	kmutex_t	tcp_rsrv_mp_lock;
469 
470 	/* For connection counting. */
471 	struct tcp_listen_cnt_s	*tcp_listen_cnt;
472 
473 	/* Segment reassembly timer. */
474 	timeout_id_t		tcp_reass_tid;
475 
476 	/* FIN-WAIT-2 flush timeout */
477 	uint32_t		tcp_fin_wait_2_flush_interval;
478 
479 #ifdef DEBUG
480 	pc_t			tcmp_stk[15];
481 #endif
482 } tcp_t;
483 
484 #ifdef DEBUG
485 #define	TCP_DEBUG_GETPCSTACK(buffer, depth)	((void) getpcstack(buffer, \
486 						    depth))
487 #else
488 #define	TCP_DEBUG_GETPCSTACK(buffer, depth)
489 #endif
490 
491 extern void	tcp_conn_reclaim(void *);
492 extern void 	tcp_free(tcp_t *tcp);
493 extern void	tcp_ddi_g_init(void);
494 extern void	tcp_ddi_g_destroy(void);
495 extern void 	*tcp_get_conn(void *arg, tcp_stack_t *);
496 extern mblk_t	*tcp_snmp_get(queue_t *, mblk_t *, boolean_t);
497 extern int	tcp_snmp_set(queue_t *, int, int, uchar_t *, int len);
498 
499 /*
500  * The TCP Fanout structure for bind and acceptor hashes.
501  * The hash tables and their linkage (tcp_*_hash, tcp_ptp*hn) are
502  * protected by the per-bucket tf_lock.  Each tcp_t
503  * inserted in the list points back at this lock using tcp_*_lockp.
504  *
505  * The bind and acceptor hash queues are lists of tcp_t.
506  */
507 /* listener hash and acceptor hash queue head */
508 typedef struct tf_s {
509 	tcp_t		*tf_tcp;
510 	kmutex_t	tf_lock;
511 } tf_t;
512 
513 
514 /* Also used in ipclassifier.c */
515 extern struct kmem_cache  *tcp_sack_info_cache;
516 
517 #endif	/* (defined(_KERNEL) || defined(_KMEMUSER)) */
518 
519 /* Contract private interface between TCP and Clustering. */
520 
521 #define	CL_TCPI_V1	1	/* cl_tcpi_version number */
522 
523 typedef struct cl_tcp_info_s {
524 	ushort_t	cl_tcpi_version;	/* cl_tcp_info_t's version no */
525 	ushort_t	cl_tcpi_ipversion;	/* IP version */
526 	int32_t		cl_tcpi_state;		/* TCP state */
527 	in_port_t	cl_tcpi_lport;		/* Local port */
528 	in_port_t	cl_tcpi_fport;		/* Remote port */
529 	in6_addr_t	cl_tcpi_laddr_v6;	/* Local IP address */
530 	in6_addr_t	cl_tcpi_faddr_v6;	/* Remote IP address */
531 #ifdef _KERNEL
532 /* Note: V4_PART_OF_V6 is meant to be used only for _KERNEL defined stuff */
533 #define	cl_tcpi_laddr	V4_PART_OF_V6(cl_tcpi_laddr_v6)
534 #define	cl_tcpi_faddr	V4_PART_OF_V6(cl_tcpi_faddr_v6)
535 
536 #endif	/* _KERNEL */
537 } cl_tcp_info_t;
538 
539 /*
540  * Hook functions to enable cluster networking
541  * On non-clustered systems these vectors must always be NULL.
542  */
543 extern void	(*cl_inet_listen)(netstackid_t, uint8_t, sa_family_t,
544 		    uint8_t *, in_port_t, void *);
545 extern void	(*cl_inet_unlisten)(netstackid_t, uint8_t, sa_family_t,
546 		    uint8_t *, in_port_t, void *);
547 
548 /*
549  * Contracted Consolidation Private ioctl for aborting TCP connections.
550  * In order to keep the offsets and size of the structure the same between
551  * a 32-bit application and a 64-bit amd64 kernel, we use a #pragma
552  * pack(4).
553  */
554 #define	TCP_IOC_ABORT_CONN	(('T' << 8) + 91)
555 
556 #if _LONG_LONG_ALIGNMENT == 8 && _LONG_LONG_ALIGNMENT_32 == 4
557 #pragma pack(4)
558 #endif
559 
560 typedef struct tcp_ioc_abort_conn_s {
561 	struct sockaddr_storage ac_local;	/* local addr and port */
562 	struct sockaddr_storage ac_remote;	/* remote addr and port */
563 	int32_t ac_start;			/* start state */
564 	int32_t ac_end;				/* end state  */
565 	int32_t ac_zoneid;			/* zoneid */
566 } tcp_ioc_abort_conn_t;
567 
568 #if _LONG_LONG_ALIGNMENT == 8 && _LONG_LONG_ALIGNMENT_32 == 4
569 #pragma pack()
570 #endif
571 
572 #ifdef	__cplusplus
573 }
574 #endif
575 
576 #endif	/* _INET_TCP_H */
577