xref: /xnu-8020.140.41/bsd/netinet/tcp_var.h (revision 27b03b360a988dfd3dfdf34262bb0042026747cc)
1 /*
2  * Copyright (c) 2000-2021 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
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10  * may not be used to create, or enable the creation or redistribution of,
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12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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23  * Please see the License for the specific language governing rights and
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26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 /*
29  * Copyright (c) 1982, 1986, 1993, 1994, 1995
30  *	The Regents of the University of California.  All rights reserved.
31  *
32  * Redistribution and use in source and binary forms, with or without
33  * modification, are permitted provided that the following conditions
34  * are met:
35  * 1. Redistributions of source code must retain the above copyright
36  *    notice, this list of conditions and the following disclaimer.
37  * 2. Redistributions in binary form must reproduce the above copyright
38  *    notice, this list of conditions and the following disclaimer in the
39  *    documentation and/or other materials provided with the distribution.
40  * 3. All advertising materials mentioning features or use of this software
41  *    must display the following acknowledgement:
42  *	This product includes software developed by the University of
43  *	California, Berkeley and its contributors.
44  * 4. Neither the name of the University nor the names of its contributors
45  *    may be used to endorse or promote products derived from this software
46  *    without specific prior written permission.
47  *
48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
61  * $FreeBSD: src/sys/netinet/tcp_var.h,v 1.56.2.8 2001/08/22 00:59:13 silby Exp $
62  */
63 
64 #ifndef _NETINET_TCP_VAR_H_
65 #define _NETINET_TCP_VAR_H_
66 #include <sys/types.h>
67 #include <sys/appleapiopts.h>
68 #include <sys/queue.h>
69 #include <netinet/in_pcb.h>
70 #include <netinet/tcp.h>
71 #include <netinet/tcp_timer.h>
72 #if !KERNEL
73 #include <TargetConditionals.h>
74 #endif
75 
76 #if defined(__LP64__)
77 #define _TCPCB_PTR(x)                   u_int32_t
78 #define _TCPCB_LIST_HEAD(name, type)    \
79 struct name {                           \
80 	u_int32_t	lh_first;       \
81 }
82 #else
83 #define _TCPCB_PTR(x)                   x
84 #define _TCPCB_LIST_HEAD(name, type)    LIST_HEAD(name, type)
85 #endif
86 
87 #ifdef KERNEL_PRIVATE
88 
89 #define TCP_RETRANSHZ   1000    /* granularity of TCP timestamps, 1ms */
90 /* Minimum time quantum within which the timers are coalesced */
91 #define TCP_TIMER_10MS_QUANTUM  (TCP_RETRANSHZ/100) /* every 10ms */
92 #define TCP_TIMER_100MS_QUANTUM   (TCP_RETRANSHZ/10) /* every 100ms */
93 #define TCP_TIMER_500MS_QUANTUM   (TCP_RETRANSHZ/2) /* every 500ms */
94 
95 #define TCP_RETRANSHZ_TO_USEC 1000
96 
97 #define N_TIME_WAIT_SLOTS   128         /* must be power of 2 */
98 
99 /* Always allow at least 16 packets worth of recv window when adjusting
100  * recv window using inter-packet arrival jitter.
101  */
102 #define MIN_IAJ_WIN 16
103 
104 /* A variation in delay of this many milliseconds is tolerable. This limit has to
105  * be low but greater than zero. We also use standard deviation on jitter to adjust
106  * this limit for different link and connection types.
107  */
108 #define ALLOWED_IAJ 5
109 
110 /* Ignore the first few packets on a connection until the ACK clock gets going
111  */
112 #define IAJ_IGNORE_PKTCNT 40
113 
114 /* Let the accumulated IAJ value increase by this threshold at most. This limit
115  * will control how many ALLOWED_IAJ measurements a receiver will have to see
116  * before opening the receive window
117  */
118 #define ACC_IAJ_HIGH_THRESH 100
119 
120 /* When accumulated IAJ reaches this value, the receiver starts to react by
121  * closing the window
122  */
123 #define ACC_IAJ_REACT_LIMIT 200
124 
125 /* If the number of small packets (smaller than IAJ packet size) seen on a
126  * connection is more than this threshold, reset the size and learn it again.
127  * This is needed because the sender might send smaller segments after PMTU
128  * discovery and the receiver has to learn the new size.
129  */
130 #define RESET_IAJ_SIZE_THRESH 20
131 
132 /*
133  * Adaptive timeout is a read/write timeout specified by the application to
134  * get a socket event when the transport layer detects a stall in data
135  * transfer. The value specified is the number of probes that can be sent
136  * to the peer before generating an event. Since it is not specified as
137  * a time value, the timeout will adjust based on the RTT seen on the link.
138  * The timeout will start only when there is an indication that the read/write
139  * operation is not making progress.
140  *
141  * If a write operation stalls, the probe will be retransmission of data.
142  * If a read operation stalls, the probe will be a keep-alive packet.
143  *
144  * The maximum value of adaptive timeout is set to 10 which will allow
145  * transmission of enough number of probes to the peer.
146  */
147 #define TCP_ADAPTIVE_TIMEOUT_MAX        10
148 
149 #define TCP_CONNECTIVITY_PROBES_MAX     5
150 
151 /*
152  * Kernel variables for tcp.
153  */
154 
155 /* TCP segment queue entry */
156 struct tseg_qent {
157 	LIST_ENTRY(tseg_qent) tqe_q;
158 	int     tqe_len;                /* TCP segment data length */
159 	struct  tcphdr *tqe_th;         /* a pointer to tcp header */
160 	struct  mbuf    *tqe_m;         /* mbuf contains packet */
161 };
162 LIST_HEAD(tsegqe_head, tseg_qent);
163 
164 struct sackblk {
165 	tcp_seq start;          /* start seq no. of sack block */
166 	tcp_seq end;            /* end seq no. */
167 };
168 
169 struct sackhole {
170 	tcp_seq start;          /* start seq no. of hole */
171 	tcp_seq end;            /* end seq no. */
172 	tcp_seq rxmit;          /* next seq. no in hole to be retransmitted */
173 	u_int32_t rxmit_start;  /* timestamp of first retransmission */
174 	TAILQ_ENTRY(sackhole) scblink;  /* scoreboard linkage */
175 };
176 
177 struct sackhint {
178 	struct sackhole *nexthole;
179 	int     sack_bytes_rexmit;
180 	int sack_bytes_acked;
181 };
182 
183 struct tcp_rxt_seg {
184 	tcp_seq rx_start;
185 	tcp_seq rx_end;
186 	u_int16_t rx_count;
187 	u_int16_t rx_flags;
188 #define TCP_RXT_SPURIOUS        0x1     /* received DSACK notification */
189 #define TCP_RXT_DSACK_FOR_TLP   0x2
190 	SLIST_ENTRY(tcp_rxt_seg) rx_link;
191 };
192 
193 struct tcp_notify_ack_marker {
194 	tcp_seq notify_snd_una; /* Notify when snd_una crosses this seq */
195 	tcp_notify_ack_id_t notify_id;
196 	SLIST_ENTRY(tcp_notify_ack_marker) notify_next;
197 };
198 
199 struct tcptemp {
200 	u_char  tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
201 	struct  tcphdr tt_t;
202 };
203 
204 struct bwmeas {
205 	tcp_seq bw_start;       /* start of bw measurement */
206 	uint32_t bw_ts;         /* timestamp when bw measurement started */
207 	uint32_t bw_size;       /* burst size in bytes for this bw measurement */
208 	uint32_t bw_minsizepkts; /* Min burst size as segments */
209 	uint32_t bw_maxsizepkts; /* Max burst size as segments */
210 	uint32_t bw_minsize;    /* Min size in bytes */
211 	uint32_t bw_maxsize;    /* Max size in bytes */
212 	uint32_t bw_sndbw;      /* Measured send bandwidth */
213 	uint32_t bw_sndbw_max;  /* Max measured bandwidth */
214 	uint32_t bw_rcvbw_max;  /* Max receive bandwidth measured */
215 };
216 
217 /* MPTCP Data sequence map entry */
218 struct mpt_dsn_map {
219 	uint64_t                mpt_dsn;        /* data seq num recvd */
220 	uint32_t                mpt_sseq;       /* relative subflow # */
221 	uint16_t                mpt_len;        /* length of mapping */
222 	uint16_t                mpt_csum;       /* checksum value if on */
223 	uint8_t                 mpt_dfin;       /* It's a DATA_FIN */
224 };
225 #define tcp6cb          tcpcb  /* for KAME src sync over BSD*'s */
226 
227 struct tcp_ccstate {
228 	union {
229 		struct tcp_cubic_state {
230 			u_int32_t tc_last_max;  /* cwnd at last loss */
231 			u_int32_t tc_epoch_start; /* TS of last loss */
232 			u_int32_t tc_origin_point; /* window at the start of an epoch */
233 			u_int32_t tc_tcp_win; /* computed tcp win */
234 			u_int32_t tc_tcp_bytes_acked; /* bytes acked */
235 			u_int32_t tc_avg_lastmax; /* Average of last max */
236 			u_int32_t tc_mean_deviation; /* Mean absolute deviation */
237 			float     tc_epoch_period; /* K parameter */
238 		} _cubic_state_;
239 #define cub_last_max __u__._cubic_state_.tc_last_max
240 #define cub_epoch_start __u__._cubic_state_.tc_epoch_start
241 #define cub_origin_point __u__._cubic_state_.tc_origin_point
242 #define cub_tcp_win __u__._cubic_state_.tc_tcp_win
243 #define cub_tcp_bytes_acked __u__._cubic_state_.tc_tcp_bytes_acked
244 #define cub_epoch_period __u__._cubic_state_.tc_epoch_period
245 #define cub_avg_lastmax __u__._cubic_state_.tc_avg_lastmax
246 #define cub_mean_dev __u__._cubic_state_.tc_mean_deviation
247 		struct tcp_ledbat_state {
248 			uint32_t num_slowdown_events;
249 			uint32_t slowdown_ts;
250 			uint32_t slowdown_begin;
251 			uint32_t md_bytes_acked;
252 		} _ledbat_state_;
253 #define ledbat_slowdown_events __u__._ledbat_state_.num_slowdown_events
254 #define ledbat_slowdown_ts __u__._ledbat_state_.slowdown_ts
255 #define ledbat_slowdown_begin __u__._ledbat_state_.slowdown_begin
256 #define ledbat_md_bytes_acked __u__._ledbat_state_.md_bytes_acked
257 	} __u__;
258 };
259 
260 struct tcp_rledbat_state {
261 	uint32_t num_slowdown_events;  /* Number of slowdown events until reset */
262 	uint32_t slowdown_ts;          /* Next slowdown timestamp */
263 	uint32_t slowdown_begin;       /* Slowdown begin time */
264 	uint32_t reduction_end;        /* Used to track rl_win reduction once per RTT */
265 	uint32_t rcvd_bytes;           /* bytes received used for byte counting */
266 	uint32_t md_rcvd_bytes;        /* bytes received during MD used for byte counting */
267 	uint32_t win;                  /* receive Ledbat window size */
268 	uint32_t ssthresh;             /* receive Ledbat ssthresh */
269 	uint32_t drained_bytes;        /* bytes drained from the flight-size */
270 	uint32_t win_ws;               /* receive Ledbat window after avoiding window shrinking */
271 };
272 
273 /*
274  * Tcp control block, one per tcp; fields:
275  * Organized for 16 byte cacheline efficiency.
276  */
277 struct tcpcb {
278 	struct tsegqe_head t_segq;
279 	uint32_t t_dupacks;             /* consecutive dup acks recd */
280 	int      t_state;               /* state of this connection */
281 	uint32_t t_timer[TCPT_NTIMERS]; /* tcp timers */
282 	struct tcptimerentry tentry;    /* entry in timer list */
283 
284 	struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
285 	uint32_t        t_flags;
286 #define TF_ACKNOW       0x00001         /* ack peer immediately */
287 #define TF_DELACK       0x00002         /* ack, but try to delay it */
288 #define TF_NODELAY      0x00004         /* don't delay packets to coalesce */
289 #define TF_NOOPT        0x00008         /* don't use tcp options */
290 #define TF_SENTFIN      0x00010         /* have sent FIN */
291 #define TF_REQ_SCALE    0x00020         /* have/will request window scaling */
292 #define TF_RCVD_SCALE   0x00040         /* other side has requested scaling */
293 #define TF_REQ_TSTMP    0x00080         /* have/will request timestamps */
294 #define TF_RCVD_TSTMP   0x00100         /* a timestamp was received in SYN */
295 #define TF_SACK_PERMIT  0x00200         /* other side said I could SACK */
296 #define TF_NEEDSYN      0x00400         /* send SYN (implicit state) - unused but needed for backwards compatibility */
297 #define TF_NEEDFIN      0x00800         /* send FIN (implicit state) */
298 #define TF_NOPUSH       0x01000         /* don't push */
299 #define TF_REQ_CC       0x02000         /* have/will request CC */
300 #define TF_RCVD_CC      0x04000         /* a CC was received in SYN */
301 #define TF_SENDCCNEW    0x08000         /* Unused */
302 #define TF_MORETOCOME   0x10000         /* More data to be appended to sock */
303 #define TF_LOCAL        0x20000         /* connection to a host on local link */
304 #define TF_RXWIN0SENT   0x40000         /* sent a receiver win 0 in response */
305 #define TF_SLOWLINK     0x80000         /* route is a on a modem speed link */
306 #define TF_LASTIDLE     0x100000        /* connection was previously idle */
307 #define TF_FASTRECOVERY 0x200000        /* in NewReno Fast Recovery */
308 #define TF_WASFRECOVERY 0x400000        /* was in NewReno Fast Recovery */
309 #define TF_SIGNATURE    0x800000        /* require MD5 digests (RFC2385) */
310 #define TF_MAXSEGSNT    0x1000000       /* last segment sent was a full segment */
311 #define TF_STREAMING_ON 0x2000000       /* Receiver detected streaming */
312 #define TF_PMTUD        0x4000000       /* Perform Path MTU Discovery for this connection */
313 #define TF_CLOSING      0x8000000       /* pending tcp close */
314 #define TF_TSO          0x10000000      /* TCP Segment Offloading is enable on this connection */
315 #define TF_BLACKHOLE    0x20000000      /* Path MTU Discovery Black Hole detection */
316 #define TF_TIMER_ONLIST 0x40000000      /* pcb is on tcp_timer_list */
317 #define TF_STRETCHACK   0x80000000      /* receiver is going to delay acks */
318 
319 	tcp_seq snd_una;                /* send unacknowledged */
320 	tcp_seq snd_max;                /* highest sequence number sent;
321 	                                 * used to recognize retransmits
322 	                                 */
323 	tcp_seq snd_nxt;                /* send next */
324 	tcp_seq snd_up;                 /* send urgent pointer */
325 
326 	tcp_seq snd_wl1;                /* window update seg seq number */
327 	tcp_seq snd_wl2;                /* window update seg ack number */
328 	tcp_seq iss;                    /* initial send sequence number */
329 	tcp_seq irs;                    /* initial receive sequence number */
330 
331 	tcp_seq rcv_nxt;                /* receive next */
332 	tcp_seq rcv_adv;                /* advertised window */
333 	uint32_t        rcv_wnd;        /* receive window */
334 	uint32_t        t_last_recwin;
335 	tcp_seq rcv_up;                 /* receive urgent pointer */
336 
337 	uint32_t        snd_wnd;        /* send window */
338 	uint32_t        snd_cwnd;       /* congestion-controlled window */
339 	uint32_t        snd_ssthresh;   /* snd_cwnd size threshold for
340 	                                 * for slow start exponential to
341 	                                 * linear switch
342 	                                 */
343 	tcp_seq snd_recover;            /* for use in NewReno Fast Recovery */
344 
345 	uint32_t        t_maxopd;       /* mss plus options */
346 	uint32_t        t_rcvtime;      /* time at which a packet was received */
347 	uint32_t        t_sndtime;      /* time at which we last sent new data */
348 	uint32_t        t_starttime;    /* time connection was established */
349 	int     t_rtttime;              /* tcp clock when rtt calculation was started */
350 	tcp_seq t_rtseq;                /* sequence number being timed */
351 
352 	uint32_t rfbuf_ts;              /* recv buffer autoscaling timestamp */
353 	uint32_t rfbuf_cnt;             /* recv buffer autoscaling byte count */
354 	uint32_t rfbuf_space;           /* Current "ideal" estimate of the space */
355 
356 	int            t_rxtcur;        /* current retransmit value (ticks) */
357 	unsigned int   t_maxseg;        /* maximum segment size */
358 	int            t_srtt;          /* smoothed round-trip time */
359 	int            t_rttvar;        /* variance in round-trip time */
360 
361 	uint64_t t_accsleep_ms;         /* accumulated sleep time since last boot */
362 	uint32_t t_reassqlen;           /* length of reassembly queue */
363 	uint32_t t_reassq_mbcnt;        /* amount in bytes of mbuf space used */
364 	uint16_t t_rxtshift;            /* log(2) of rexmt exp. backoff */
365 	uint32_t t_rttmin;              /* minimum rtt allowed */
366 	uint32_t t_rttbest;             /* best rtt we've seen */
367 	uint32_t t_rttcur;              /* most recent value of rtt */
368 	uint32_t t_rttupdated;          /* number of times rtt sampled */
369 	uint32_t t_rxt_conndroptime;    /* retxmt conn gets dropped after this time, when set */
370 	uint32_t t_rxtstart;            /* time at which retransmission started */
371 	uint32_t max_sndwnd;            /* largest window peer has offered */
372 
373 	int     t_softerror;            /* possible error not yet reported */
374 /* out-of-band data */
375 	char    t_oobflags;             /* have some */
376 	char    t_iobc;                 /* input character */
377 #define TCPOOB_HAVEDATA 0x01
378 #define TCPOOB_HADDATA  0x02
379 /* RFC 1323 variables */
380 	u_int8_t        snd_scale;      /* window scaling for send window */
381 	u_int8_t        rcv_scale;      /* window scaling for recv window */
382 	u_int8_t        request_r_scale; /* pending window scaling */
383 	u_int8_t        requested_s_scale;
384 	u_int8_t        tcp_cc_index;   /* index of congestion control algorithm */
385 	u_int8_t        t_adaptive_rtimo;       /* Read timeout used as a multiple of RTT */
386 	u_int8_t        t_adaptive_wtimo;       /* Write timeout used as a multiple of RTT */
387 	u_int8_t        t_stretchack_delayed;   /* stretch ack delayed */
388 
389 /* State for limiting early retransmits when SACK is not enabled */
390 	u_int16_t       t_early_rexmt_count; /* count of early rexmts */
391 	u_int32_t       t_early_rexmt_win; /* window for limiting early rexmts */
392 
393 	u_int32_t       ts_recent;      /* timestamp echo data */
394 
395 	u_int32_t       ts_recent_age;  /* when last updated */
396 	tcp_seq last_ack_sent;
397 /* RFC 3465 variables */
398 	u_int32_t       t_bytes_acked;  /* ABC "bytes_acked" parameter */
399 
400 	int             t_lastchain;    /* amount of packets chained last time around */
401 	uint16_t        t_unacksegs;    /* received but unacked segments for delaying acks */
402 
403 	/*
404 	 * Pretty arbitrary value ;-)
405 	 * Goal is to make sure that some ACKs are being sent more frequently
406 	 * to allow the other side to ramp-up.
407 	 */
408 #define TCP_FORCED_ACKS_COUNT 16
409 	uint16_t        t_forced_acks;  /* count of pure ACKs that need to be forced out */
410 	uint8_t         t_rexmtthresh;  /* duplicate ack threshold for entering fast recovery */
411 	uint8_t         t_rtimo_probes; /* number of adaptive rtimo probes sent */
412 	uint32_t        t_persist_timeout; /* ZWP persistence limit as set by PERSIST_TIMEOUT */
413 	uint32_t        t_persist_stop;    /* persistence limit deadline if triggered by ZWP */
414 	uint32_t        t_notsent_lowat;   /* Low water for not sent data */
415 
416 /* Receiver state for stretch-ack algorithm */
417 	u_int32_t       rcv_unackwin;   /* to measure win for stretching acks */
418 	u_int32_t       rcv_by_unackwin; /* bytes seen during the last ack-stretching win */
419 	u_int32_t       rcv_by_unackhalfwin;
420 	u_int32_t       rcv_nostrack_ts; /* timestamp when stretch ack was disabled automatically */
421 	u_int32_t       rcv_nostrack_pkts; /* pkts received since strech ack was disabled */
422 	u_int16_t       rcv_waitforss;  /* wait for packets during slow-start */
423 
424 /* ECN stats */
425 	u_int16_t       ecn_flags;
426 #define TE_SETUPSENT            0x0001  /* Indicate we have sent ECN-SETUP SYN or SYN-ACK */
427 #define TE_SETUPRECEIVED        0x0002  /* Indicate we have received ECN-SETUP SYN or SYN-ACK */
428 #define TE_SENDIPECT            0x0004  /* Indicate we haven't sent or received non-ECN-setup SYN or SYN-ACK */
429 #define TE_SENDCWR              0x0008  /* Indicate that the next non-retransmit should have the TCP CWR flag set */
430 #define TE_SENDECE              0x0010  /* Indicate that the next packet should have the TCP ECE flag set */
431 #define TE_INRECOVERY           0x0020  /* connection entered recovery after receiving ECE */
432 #define TE_RECV_ECN_CE          0x0040  /* Received IPTOS_ECN_CE marking atleast once */
433 #define TE_RECV_ECN_ECE         0x0080  /* Received ECE marking atleast once */
434 #define TE_LOST_SYN             0x0100  /* Lost SYN with ECN setup */
435 #define TE_LOST_SYNACK          0x0200  /* Lost SYN-ACK with ECN setup */
436 #define TE_ECN_MODE_ENABLE      0x0400  /* Option ECN mode set to enable */
437 #define TE_ECN_MODE_DISABLE     0x0800  /* Option ECN mode set to disable */
438 #define TE_ENABLE_ECN           0x1000  /* Enable negotiation of ECN */
439 #define TE_ECN_ON               (TE_SETUPSENT | TE_SETUPRECEIVED) /* Indicate ECN was successfully negotiated on a connection) */
440 #define TE_CEHEURI_SET          0x2000 /* We did our CE-probing at the beginning */
441 #define TE_CLIENT_SETUP         0x4000  /* setup from client side */
442 #define TE_RCVD_SYN_RST         0x8000  /* Received RST to the first ECN enabled SYN */
443 
444 	u_int32_t       t_ecn_recv_ce;  /* Received CE from the network */
445 	u_int32_t       t_ecn_recv_cwr; /* Packets received with CWR */
446 
447 /* state for bad retransmit recovery */
448 	u_int32_t       snd_cwnd_prev;  /* cwnd prior to retransmit */
449 	u_int32_t       snd_ssthresh_prev; /* ssthresh prior to retransmit */
450 	tcp_seq snd_recover_prev;       /* snd_recover prior to retransmit */
451 	int     t_srtt_prev;            /* srtt prior to retransmit */
452 	int     t_rttvar_prev;          /* rttvar prior to retransmit */
453 	u_int32_t       t_badrexmt_time; /* bad rexmt detection time */
454 
455 /* Packet reordering metric */
456 	u_int32_t       t_reorderwin; /* Reordering late time offset */
457 
458 /* SACK related state */
459 	int16_t snd_numholes;           /* number of holes seen by sender */
460 	tcp_seq sack_newdata;           /* New data xmitted in this recovery
461 	                                 *   episode starts at this seq number */
462 	TAILQ_HEAD(sackhole_head, sackhole) snd_holes;
463 	/* SACK scoreboard (sorted) */
464 	tcp_seq snd_fack;               /* last seq number(+1) sack'd by rcv'r*/
465 	int     rcv_numsacks;           /* # distinct sack blks present */
466 	struct sackblk sackblks[MAX_SACK_BLKS]; /* seq nos. of sack blocks */
467 	struct sackhint sackhint;       /* SACK scoreboard hint */
468 	tcp_seq         send_highest_sack; /* Sequence number of fresh data sent after the most recent fast-retransmit */
469 	int             t_new_dupacks; /* Dupacks received above send_highest_sack */
470 
471 	struct mbuf     *t_pktlist_head; /* First packet in transmit chain */
472 	struct mbuf     *t_pktlist_tail; /* Last packet in transmit chain */
473 	u_int32_t       t_pktlist_sentlen; /* total bytes in transmit chain */
474 
475 	u_int32_t       t_keepidle;     /* keepalive idle timer (override global if > 0) */
476 	u_int32_t       t_keepinit;     /* connection timeout, i.e. idle time
477 	                                 *  in SYN_SENT or SYN_RECV state */
478 	u_int32_t       t_keepintvl;    /* interval between keepalives */
479 	u_int32_t       t_keepcnt;      /* number of keepalives before close */
480 
481 	u_int32_t       tso_max_segment_size;   /* TSO maximum segment unit for NIC */
482 	u_int16_t       t_pmtud_lastseg_size;   /* size of the last sent segment */
483 	u_int32_t       t_pmtud_saved_maxopd;   /* MSS saved before performing PMTU-D BlackHole detection */
484 	u_int32_t       t_pmtud_start_ts;       /* Time of PMTUD blackhole detection */
485 
486 	struct{
487 		u_int32_t       rxduplicatebytes;
488 		u_int32_t       rxoutoforderbytes;
489 		u_int32_t       txretransmitbytes;
490 		u_int16_t       synrxtshift;
491 		u_int16_t       rxmitsyns;
492 		u_int16_t       unused_pad_to_8;
493 		u_int32_t       rxmitpkts;
494 		uint32_t        delayed_acks_sent;
495 		uint32_t        acks_delayed;
496 	} t_stat;
497 	u_int8_t        t_notify_ack_count;
498 	u_int8_t        t_ecn_recv_ce_pkt; /* Received packet with CE-bit set (independent from last_ack_sent) */
499 	u_int32_t       t_cached_maxopd; /* default for MSS adjustment using link status report */
500 
501 	uint32_t        bg_ssthresh;            /* Slow start threshold until delay increases */
502 	uint32_t        t_flagsext;             /* Another field to accommodate more flags */
503 #define TF_RXTFINDROP           0x1                     /* Drop conn after retransmitting FIN 3 times */
504 #define TF_RCVUNACK_WAITSS      0x2             /* set when the receiver should not stretch acks */
505 #define TF_BWMEAS_INPROGRESS    0x4             /* Indicate BW meas is happening */
506 #define TF_MEASURESNDBW         0x8             /* Measure send bw on this connection */
507 #define TF_LAST_IS_PSH          0x10            /* Indicates whether the last packet in the rcv socket buffer had the PUSH-flag set */
508 #define TF_SACK_ENABLE          0x20            /* SACK is enabled */
509 #define TF_RECOMPUTE_RTT        0x40            /* recompute RTT after spurious retransmit */
510 #define TF_DETECT_READSTALL     0x80            /* Used to detect a stall during read operation */
511 #define TF_RECV_THROTTLE        0x100           /* Input throttling active */
512 #define TF_NOSTRETCHACK         0x200           /* ack every other packet */
513 #define TF_NOTIMEWAIT           0x800           /* Avoid going into time-wait */
514 #define TF_SENT_TLPROBE         0x1000          /* Sent data in PTO */
515 #define TF_PKTS_REORDERED       0x2000          /* Detected reordering */
516 #define TF_DELAY_RECOVERY       0x4000          /* delay fast recovery */
517 #define TF_FORCE                0x8000          /* force 1 byte out */
518 #define TF_DISABLE_STRETCHACK   0x10000         /* auto-disable stretch ack */
519 #define TF_NOBLACKHOLE_DETECTION 0x20000        /* Disable PMTU blackhole detection */
520 #define TF_RESCUE_RXT           0x80000         /* SACK rescue retransmit */
521 #define TF_CWND_NONVALIDATED    0x100000        /* cwnd non validated */
522 #define TF_IF_PROBING           0x200000        /* Trigger interface probe timeout */
523 #define TF_FASTOPEN             0x400000        /* TCP Fastopen is enabled */
524 #define TF_REASS_INPROG         0x800000        /* Reassembly is in progress */
525 #define TF_FASTOPEN_FORCE_ENABLE 0x1000000      /* Force-enable TCP Fastopen */
526 #define TF_LOGGED_CONN_SUMMARY  0x2000000       /* Connection summary was logged */
527 
528 #if TRAFFIC_MGT
529 	/* Inter-arrival jitter related state */
530 	uint32_t        iaj_rcv_ts;             /* tcp clock when the first packet was received */
531 	int             iaj_size;               /* Size of packet for iaj measurement */
532 	uint8_t         iaj_small_pkt;          /* Count of packets smaller than iaj_size */
533 	uint8_t         t_pipeack_ind;          /* index for next pipeack sample */
534 	uint16_t        iaj_pktcnt;             /* packet count, to avoid throttling initially */
535 	uint32_t        acc_iaj;                /* Accumulated iaj */
536 	uint32_t        avg_iaj;                /* Mean */
537 	uint32_t        std_dev_iaj;            /* Standard deviation */
538 #endif /* TRAFFIC_MGT */
539 	struct bwmeas   *t_bwmeas;              /* State for bandwidth measurement */
540 	tcp_seq         t_idleat;               /* rcv_nxt at idle time */
541 	TAILQ_ENTRY(tcpcb) t_twentry;           /* link for time wait queue */
542 	struct tcp_ccstate      *t_ccstate;     /* congestion control related state */
543 /* Tail loss probe related state */
544 	tcp_seq         t_tlphighrxt;           /* snd_nxt after PTO */
545 	u_int32_t       t_tlpstart;             /* timestamp at PTO */
546 /* DSACK data receiver state */
547 	tcp_seq         t_dsack_lseq;           /* DSACK left sequence */
548 	tcp_seq         t_dsack_rseq;           /* DSACK right sequence */
549 /* DSACK data sender state */
550 	SLIST_HEAD(tcp_rxt_seghead, tcp_rxt_seg) t_rxt_segments;
551 	uint32_t        t_rxt_seg_count;
552 	uint32_t        t_rxt_seg_drop;
553 	tcp_seq         t_dsack_lastuna;        /* snd_una when last recovery episode started */
554 /* state for congestion window validation (draft-ietf-tcpm-newcwv-07) */
555 #define TCP_PIPEACK_SAMPLE_COUNT        3
556 	u_int32_t       t_pipeack_sample[TCP_PIPEACK_SAMPLE_COUNT];     /* pipeack, bytes acked within RTT */
557 	tcp_seq         t_pipeack_lastuna; /* una when pipeack measurement started */
558 	u_int32_t       t_pipeack;
559 	u_int32_t       t_lossflightsize;
560 
561 #if MPTCP
562 	u_int32_t       t_mpflags;              /* flags for multipath TCP */
563 
564 #define TMPF_PREESTABLISHED     0x00000001 /* conn in pre-established state */
565 #define TMPF_SND_KEYS           0x00000002 /* indicates that keys should be send */
566 #define TMPF_MPTCP_TRUE         0x00000004 /* negotiated MPTCP successfully */
567 #define TMPF_MPTCP_RCVD_KEY     0x00000008 /* state for 3-way handshake */
568 #define TMPF_SND_MPPRIO         0x00000010 /* send priority of subflow */
569 #define TMPF_SND_REM_ADDR       0x00000020 /* initiate address removal */
570 #define TMPF_RCVD_DACK          0x00000040 /* received a data-ack */
571 #define TMPF_JOINED_FLOW        0x00000080 /* Indicates additional flow */
572 #define TMPF_BACKUP_PATH        0x00000100 /* Indicates backup path */
573 #define TMPF_MPTCP_ACKNOW       0x00000200 /* Send Data ACK */
574 #define TMPF_SEND_DSN           0x00000400 /* Send DSN mapping */
575 #define TMPF_SEND_DFIN          0x00000800 /* Send Data FIN */
576 #define TMPF_RECV_DFIN          0x00001000 /* Recv Data FIN */
577 #define TMPF_SENT_JOIN          0x00002000 /* Sent Join */
578 #define TMPF_RECVD_JOIN         0x00004000 /* Received Join */
579 #define TMPF_RESET              0x00008000 /* Send RST */
580 #define TMPF_TCP_FALLBACK       0x00010000 /* Fallback to TCP */
581 #define TMPF_FASTCLOSERCV       0x00020000 /* Received Fastclose option */
582 #define TMPF_EMBED_DSN          0x00040000 /* tp has DSN mapping */
583 #define TMPF_MPTCP_READY        0x00080000 /* Can send DSS options on data */
584 #define TMPF_INFIN_SENT         0x00100000 /* Sent infinite mapping */
585 #define TMPF_SND_MPFAIL         0x00200000 /* Received mapping csum failure */
586 #define TMPF_SND_JACK           0x00400000 /* Send a Join-ACK */
587 #define TMPF_TFO_REQUEST        0x00800000 /* TFO Requested */
588 #define TMPF_MPTCP_ECHO_ADDR    0x01000000 /* MPTCP echoes add_addr */
589 
590 #define TMPF_MPTCP_SIGNALS      (TMPF_SND_MPPRIO | TMPF_SND_REM_ADDR | TMPF_SND_MPFAIL | TMPF_SND_KEYS | TMPF_SND_JACK)
591 
592 	tcp_seq                 t_mpuna;        /* unacknowledged sequence */
593 	struct mptcb            *t_mptcb;       /* pointer to MPTCP TCB */
594 	struct mptsub           *t_mpsub;       /* pointer to the MPTCP subflow */
595 	struct mpt_dsn_map      t_rcv_map;      /* Receive mapping list */
596 	u_int8_t                t_local_aid;    /* Addr Id for authentication */
597 	u_int8_t                t_rem_aid;      /* Addr ID of another subflow */
598 	u_int8_t                t_mprxtshift;   /* join retransmission */
599 #endif /* MPTCP */
600 
601 #define TFO_F_OFFER_COOKIE      0x01 /* We will offer a cookie */
602 #define TFO_F_COOKIE_VALID      0x02 /* The received cookie is valid */
603 #define TFO_F_COOKIE_REQ        0x04 /* Client requested a new cookie */
604 #define TFO_F_COOKIE_SENT       0x08 /* Client did send a cookie in the SYN */
605 #define TFO_F_SYN_LOSS          0x10 /* A SYN-loss triggered a fallback to regular TCP on the client-side */
606 #define TFO_F_NO_SNDPROBING     0x20 /* This network is guaranteed to support TFO in the upstream direction */
607 #define TFO_F_HEURISTIC_DONE    0x40 /* We have already marked this network as bad */
608 	u_int8_t                t_tfo_flags;
609 #define TFO_S_SYNDATA_RCV       0x01 /* SYN+data has been received */
610 #define TFO_S_COOKIEREQ_RECV    0x02 /* TFO-cookie request received */
611 #define TFO_S_COOKIE_SENT       0x04 /* TFO-cookie announced in SYN/ACK */
612 #define TFO_S_COOKIE_INVALID    0x08 /* Received TFO-cookie is invalid */
613 #define TFO_S_COOKIE_REQ        0x10 /* TFO-cookie requested within the SYN */
614 #define TFO_S_COOKIE_RCV        0x20 /* TFO-cookie received in SYN/ACK */
615 #define TFO_S_SYN_DATA_SENT     0x40 /* SYN+data sent */
616 #define TFO_S_SYN_DATA_ACKED    0x80 /* SYN+data has been acknowledged in SYN/ACK */
617 #define TFO_S_SYN_LOSS          0x0100 /* SYN+TFO has been lost - fallback to regular TCP */
618 #define TFO_S_COOKIE_WRONG      0x0200 /* Cookie we sent in the SYN was wrong */
619 #define TFO_S_NO_COOKIE_RCV     0x0400 /* We asked for a cookie but didn't get one */
620 #define TFO_S_HEURISTICS_DISABLE 0x0800 /* TFO-heuristics disabled it for this connection */
621 #define TFO_S_SEND_BLACKHOLE    0x1000 /* TFO got blackholed in the send direction */
622 #define TFO_S_RECV_BLACKHOLE    0x2000 /* TFO got blackholed in the recv direction */
623 #define TFO_S_ONE_BYTE_PROXY    0x4000 /* TFO failed because of a proxy acknowledging just one byte */
624 	u_int16_t               t_tfo_stats;
625 
626 	u_int8_t                t_tfo_probes; /* TFO-probes we did send */
627 /*
628  * This here is the TFO-probing state-machine. Transitions are as follows:
629  *
630  * Current state: PROBE_NONE
631  *		  Event: SYN+DATA acknowledged
632  *			 Action: Transition to PROBE_PROBING and set keepalive-timer
633  *
634  * Current state: PROBE_PROBING (initial state)
635  *		  Event: Receive data
636  *			 Action: Transition to PROBE_NONE and cancel keepalive-timer
637  *		  Event: Receive ACK that does not indicate a hole
638  *			 Action: Transition to PROBE_NONE and cancel keepalive-timer
639  *		  Event: Receive ACK that indicates a hole
640  *			 Action: Transition to PROBE_WAIT_DATA and set a short timer
641  *				 to wait for the final segment.
642  *		  Event: Keepalive-timeout (did not receive any segment)
643  *			 Action: Signal ETIMEDOUT as with regular keepalive-timers
644  *
645  * Current state: PROBE_WAIT_DATA
646  *		  Event: Receive data
647  *			 Action: Transition to PROBE_NONE and cancel keepalive-timer
648  *		  Event: Data-timeout (did not receive the expected data)
649  *			 Action: Signal ENODATA up to the app and close everything.
650  */
651 #define TFO_PROBE_NONE          0 /* Not probing now */
652 #define TFO_PROBE_PROBING       1 /* Sending out TCP-keepalives waiting for reply */
653 #define TFO_PROBE_WAIT_DATA     2 /* Received reply, waiting for data */
654 	u_int8_t                t_tfo_probe_state;
655 
656 	u_int32_t       t_rcvoopack;            /* out-of-order packets received */
657 	u_int32_t       t_pawsdrop;             /* segments dropped due to PAWS */
658 	u_int32_t       t_sack_recovery_episode; /* SACK recovery episodes */
659 	u_int32_t       t_reordered_pkts;       /* packets reorderd */
660 	u_int32_t       t_dsack_sent;           /* Sent DSACK notification */
661 	u_int32_t       t_dsack_recvd;          /* Received a valid DSACK option */
662 	SLIST_HEAD(, tcp_notify_ack_marker) t_notify_ack; /* state for notifying data acknowledgements */
663 	u_int32_t       t_recv_throttle_ts;     /* TS for start of recv throttle */
664 	u_int32_t       t_rxt_minimum_timeout;  /* minimum retransmit timeout in ms */
665 	uint32_t        t_challengeack_last;    /* last time challenge ACK was sent per sec */
666 	uint32_t        t_challengeack_count;   /* # of challenge ACKs already sent per sec */
667 
668 	u_int32_t       t_log_flags;            /* TCP logging flags*/
669 	u_int32_t       t_connect_time;         /* time when the connection started */
670 
671 	uint32_t        t_comp_gencnt; /* Current compression generation-count */
672 	uint32_t        t_comp_lastinc; /* Last time the gen-count was changed - should change every TCP_COMP_CHANGE_RATE ms */
673 #define TCP_COMP_CHANGE_RATE    5 /* Intervals at which we change the gencnt. Means that worst-case we send one ACK every TCP_COMP_CHANGE_RATE ms */
674 
675 	uint32_t        t_ts_offset; /* Randomized timestamp offset to hide on-the-wire timestamp */
676 
677 #define NCURR_RTT_HIST 4                         /* Number of current RTT samples (k) */
678 	uint32_t curr_rtt_hist[NCURR_RTT_HIST];  /* last k current RTT samples */
679 	uint32_t curr_rtt_min;                   /* Minimum current RTT from last k samples */
680 	uint32_t curr_rtt_index;                 /* Index for current RTT samples */
681 
682 	tcp_seq rcv_high;                   /* highest sequence number received */
683 	uint32_t tsv_high;                  /* timestamp value of highest received sequence number */
684 	struct tcp_rledbat_state t_rlstate; /* State used by rLedbat */
685 
686 	uint32_t rcv_srtt;                  /* receiver's SRTT, coarse when Timestamp not supported */
687 	uint32_t rcv_rtt_est_ts;            /* start of measurement for estimating RTT when Timestamp not supported */
688 	uint32_t rcv_rtt_est_seq;           /* expected sequence number for completion of 1RTT when Timestamp not supported */
689 
690 	uuid_t          t_fsw_uuid;
691 	uuid_t          t_flow_uuid;
692 };
693 
694 #define IN_FASTRECOVERY(tp)     (tp->t_flags & TF_FASTRECOVERY)
695 #define SACK_ENABLED(tp)        (tp->t_flagsext & TF_SACK_ENABLE)
696 
697 /*
698  * If the connection is in a throttled state due to advisory feedback from
699  * the interface output queue, reset that state. We do this in favor
700  * of entering recovery because the data transfer during recovery
701  * should be just a trickle and it will help to improve performance.
702  * We also do not want to back off twice in the same RTT.
703  */
704 #define ENTER_FASTRECOVERY(_tp_) do {                                           \
705 	(_tp_)->t_flags |= TF_FASTRECOVERY;                                     \
706 	if (INP_IS_FLOW_CONTROLLED((_tp_)->t_inpcb))                            \
707 	        inp_reset_fc_state((_tp_)->t_inpcb);                            \
708 	if (!SLIST_EMPTY(&tp->t_rxt_segments))                                  \
709 	        tcp_rxtseg_clean(tp);                                           \
710 	(_tp_)->t_new_dupacks = 0;                                              \
711 } while(0)
712 
713 #define EXIT_FASTRECOVERY(_tp_) do {                                            \
714 	(_tp_)->t_flags &= ~TF_FASTRECOVERY;                                    \
715 	(_tp_)->t_dupacks = 0;                                                  \
716 	(_tp_)->t_new_dupacks = 0;                                              \
717 	(_tp_)->t_rexmtthresh = (uint8_t)tcprexmtthresh;                        \
718 	(_tp_)->t_bytes_acked = 0;                                              \
719 	(_tp_)->ecn_flags &= ~TE_INRECOVERY;                                    \
720 	(_tp_)->t_timer[TCPT_PTO] = 0;                                          \
721 	(_tp_)->t_flagsext &= ~TF_RESCUE_RXT;                                   \
722 	(_tp_)->t_lossflightsize = 0;                                           \
723 	(_tp_)->sackhint.sack_bytes_acked = 0;                                  \
724 } while(0)
725 
726 /*
727  * When the number of duplicate acks received is less than
728  * the retransmit threshold, use Limited Transmit algorithm
729  */
730 extern uint8_t tcprexmtthresh;
731 #define ALLOW_LIMITED_TRANSMIT(_tp_)                                            \
732 	((_tp_)->t_dupacks > 0 &&                                               \
733 	(_tp_)->t_dupacks < (_tp_)->t_rexmtthresh &&                            \
734 	((_tp_)->t_flagsext & (TF_PKTS_REORDERED|TF_DELAY_RECOVERY))            \
735 	    != (TF_PKTS_REORDERED|TF_DELAY_RECOVERY))
736 
737 /*
738  * This condition is true is timestamp option is supported
739  * on a connection.
740  */
741 #define TSTMP_SUPPORTED(_tp_) \
742 	(((_tp_)->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP)) == \
743 	        (TF_REQ_TSTMP|TF_RCVD_TSTMP))
744 
745 /*
746  * This condition is true if window scale option is supported
747  * on a connection
748  */
749 #define TCP_WINDOW_SCALE_ENABLED(_tp_) \
750 	(((_tp_)->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == \
751 	        (TF_RCVD_SCALE|TF_REQ_SCALE))
752 
753 /* Is ECN enabled end-to-end */
754 #define TCP_ECN_ENABLED(_tp_) \
755 	(((_tp_)->ecn_flags & (TE_ECN_ON)) == (TE_ECN_ON))
756 
757 /*
758  * Gives number of bytes acked by this ack
759  */
760 #define BYTES_ACKED(_th_, _tp_) \
761 	((_th_)->th_ack - (_tp_)->snd_una)
762 
763 /* Returns true if a DSACK option should be sent */
764 #define TCP_SEND_DSACK_OPT(_tp_) \
765 	((_tp_)->t_dsack_lseq > 0 && (_tp_)->t_dsack_rseq > 0)
766 
767 /*
768  * Returns true if a DSACK sequence is within the max send window that will
769  * be accepted. In order to set a window to validate sequence numbers, the
770  * max send window within which a DSACK option is processed is limited.
771  *
772  * We need to choose a maximum window to check if the sequence number is
773  * within the window. One arbitrary choice is 256 * MSS because if the
774  * window is as large as 256 segments it might be big enough to ignore the
775  * DSACK option. Choosing a much larger limit means that the memory for
776  * retransmit segments can be held for a longer time.
777  */
778 #define TCP_DSACK_MAX_SEND_WINDOW(_tp_) (MIN((_tp_)->snd_wnd, tcp_autosndbuf_max))
779 #define TCP_DSACK_SEQ_IN_WINDOW(_tp_, _seq_, _una_) \
780     (SEQ_LEQ((_seq_), (_tp_)->snd_max) && \
781     SEQ_GEQ((_seq_), ((_una_) - TCP_DSACK_MAX_SEND_WINDOW(_tp_))))
782 
783 #define TCP_RESET_REXMT_STATE(_tp_) do { \
784 	(_tp_)->t_rxtshift = 0; \
785 	(_tp_)->t_rxtstart = 0; \
786 	mptcp_reset_rexmit_state((_tp_)); \
787 } while(0);
788 
789 #define TCP_IF_STATE_CHANGED(tp, probe_if_index)                        \
790 	(probe_if_index > 0 && tp->t_inpcb->inp_last_outifp != NULL &&  \
791 	probe_if_index == tp->t_inpcb->inp_last_outifp->if_index)
792 
793 #define TCP_RLEDBAT_ENABLED(_tp) \
794     (tcp_rledbat == 1 && TSTMP_SUPPORTED(_tp))
795 
796 #define TCP_RECV_BG(_so) \
797     (tcp_recv_bg == 1 || IS_TCP_RECV_BG(_so))
798 
799 #define TCP_USE_RLEDBAT(_tp, _so) \
800     TCP_RLEDBAT_ENABLED(_tp) && TCP_RECV_BG(_so)
801 
802 /*
803  * Structure to hold TCP options that are only used during segment
804  * processing (in tcp_input), but not held in the tcpcb.
805  * It's basically used to reduce the number of parameters
806  * to tcp_dooptions.
807  */
808 struct tcpopt {
809 	uint32_t        to_flags;               /* which options are present */
810 #define TOF_TS          0x0001          /* timestamp */
811 #define TOF_MSS         0x0010
812 #define TOF_SCALE       0x0020
813 #define TOF_SIGNATURE   0x0040  /* signature option present */
814 #define TOF_SIGLEN      0x0080  /* signature length valid (RFC2385) */
815 #define TOF_SACK        0x0100          /* Peer sent SACK option */
816 #define TOF_MPTCP       0x0200  /* MPTCP options to be dropped */
817 #define TOF_TFO         0x0400  /* TFO cookie option present */
818 #define TOF_TFOREQ      0x0800  /* TFO cookie request present */
819 	uint32_t        to_tsval;
820 	uint32_t        to_tsecr;
821 	uint16_t        to_mss;
822 	uint8_t         to_requested_s_scale;
823 	uint8_t         to_nsacks;      /* number of SACK blocks */
824 	u_char          *to_sacks;      /* pointer to the first SACK blocks */
825 	u_char          *to_tfo;        /* pointer to the TFO cookie */
826 };
827 
828 #define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
829 #define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))
830 
831 /* TFO-specific defines */
832 #define TFO_COOKIE_LEN_MIN      4
833 #define TFO_COOKIE_LEN_DEFAULT  8
834 #define TFO_COOKIE_LEN_MAX      16
835 
836 /*
837  * The initial retransmission should happen at rtt + 4 * rttvar.
838  * Because of the way we do the smoothing, srtt and rttvar
839  * will each average +1/2 tick of bias.  When we compute
840  * the retransmit timer, we want 1/2 tick of rounding and
841  * 1 extra tick because of +-1/2 tick uncertainty in the
842  * firing of the timer.  The bias will give us exactly the
843  * 1.5 tick we need.  But, because the bias is
844  * statistical, we have to test that we don't drop below
845  * the minimum feasible timer (which is 2 ticks).
846  * This version of the macro adapted from a paper by Lawrence
847  * Brakmo and Larry Peterson which outlines a problem caused
848  * by insufficient precision in the original implementation,
849  * which results in inappropriately large RTO values for very
850  * fast networks.
851  */
852 #define TCP_REXMTVAL(tp) \
853 	max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
854 	  + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
855 
856 /*
857  * Jaguar compatible TCP control block, for xtcpcb
858  * Does not have the old fields
859  */
860 struct otcpcb {
861 #else
862 struct tseg_qent;
863 _TCPCB_LIST_HEAD(tsegqe_head, tseg_qent);
864 
865 struct tcpcb {
866 #endif /* KERNEL_PRIVATE */
867 #if defined(KERNEL_PRIVATE)
868 	u_int32_t t_segq;
869 #else
870 	struct  tsegqe_head t_segq;
871 #endif /* KERNEL_PRIVATE */
872 	int     t_dupacks;              /* consecutive dup acks recd */
873 	u_int32_t unused;               /* unused now: was t_template */
874 
875 	int     t_timer[TCPT_NTIMERS_EXT];      /* tcp timers */
876 
877 	_TCPCB_PTR(struct inpcb *) t_inpcb;     /* back pointer to internet pcb */
878 	int     t_state;                /* state of this connection */
879 	u_int   t_flags;
880 #define TF_ACKNOW       0x00001         /* ack peer immediately */
881 #define TF_DELACK       0x00002         /* ack, but try to delay it */
882 #define TF_NODELAY      0x00004         /* don't delay packets to coalesce */
883 #define TF_NOOPT        0x00008         /* don't use tcp options */
884 #define TF_SENTFIN      0x00010         /* have sent FIN */
885 #define TF_REQ_SCALE    0x00020         /* have/will request window scaling */
886 #define TF_RCVD_SCALE   0x00040         /* other side has requested scaling */
887 #define TF_REQ_TSTMP    0x00080         /* have/will request timestamps */
888 #define TF_RCVD_TSTMP   0x00100         /* a timestamp was received in SYN */
889 #define TF_SACK_PERMIT  0x00200         /* other side said I could SACK */
890 #define TF_NEEDSYN      0x00400         /* send SYN (implicit state) - unused but needed for backwards compatibility */
891 #define TF_NEEDFIN      0x00800         /* send FIN (implicit state) */
892 #define TF_NOPUSH       0x01000         /* don't push */
893 #define TF_REQ_CC       0x02000         /* have/will request CC */
894 #define TF_RCVD_CC      0x04000         /* a CC was received in SYN */
895 #define TF_SENDCCNEW    0x08000         /* Not implemented */
896 #define TF_MORETOCOME   0x10000         /* More data to be appended to sock */
897 #define TF_LQ_OVERFLOW  0x20000         /* listen queue overflow */
898 #define TF_RXWIN0SENT   0x40000         /* sent a receiver win 0 in response */
899 #define TF_SLOWLINK     0x80000         /* route is a on a modem speed link */
900 
901 	int     t_force;                /* 1 if forcing out a byte */
902 
903 	tcp_seq snd_una;                /* send unacknowledged */
904 	tcp_seq snd_max;                /* highest sequence number sent;
905 	                                 * used to recognize retransmits
906 	                                 */
907 	tcp_seq snd_nxt;                /* send next */
908 	tcp_seq snd_up;                 /* send urgent pointer */
909 
910 	tcp_seq snd_wl1;                /* window update seg seq number */
911 	tcp_seq snd_wl2;                /* window update seg ack number */
912 	tcp_seq iss;                    /* initial send sequence number */
913 	tcp_seq irs;                    /* initial receive sequence number */
914 
915 	tcp_seq rcv_nxt;                /* receive next */
916 	tcp_seq rcv_adv;                /* advertised window */
917 	u_int32_t rcv_wnd;              /* receive window */
918 	tcp_seq rcv_up;                 /* receive urgent pointer */
919 
920 	u_int32_t snd_wnd;              /* send window */
921 	u_int32_t snd_cwnd;             /* congestion-controlled window */
922 	u_int32_t snd_ssthresh;         /* snd_cwnd size threshold for
923 	                                 * for slow start exponential to
924 	                                 * linear switch
925 	                                 */
926 	u_int   t_maxopd;               /* mss plus options */
927 
928 	u_int32_t t_rcvtime;            /* time at which a packet was received */
929 	u_int32_t t_starttime;          /* time connection was established */
930 	int     t_rtttime;              /* round trip time */
931 	tcp_seq t_rtseq;                /* sequence number being timed */
932 
933 	int     t_rxtcur;               /* current retransmit value (ticks) */
934 	u_int   t_maxseg;               /* maximum segment size */
935 	int     t_srtt;                 /* smoothed round-trip time */
936 	int     t_rttvar;               /* variance in round-trip time */
937 
938 	int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
939 	u_int   t_rttmin;               /* minimum rtt allowed */
940 	u_int32_t t_rttupdated;         /* number of times rtt sampled */
941 	u_int32_t max_sndwnd;           /* largest window peer has offered */
942 
943 	int     t_softerror;            /* possible error not yet reported */
944 /* out-of-band data */
945 	char    t_oobflags;             /* have some */
946 	char    t_iobc;                 /* input character */
947 #define TCPOOB_HAVEDATA 0x01
948 #define TCPOOB_HADDATA  0x02
949 /* RFC 1323 variables */
950 	u_char  snd_scale;              /* window scaling for send window */
951 	u_char  rcv_scale;              /* window scaling for recv window */
952 	u_char  request_r_scale;        /* pending window scaling */
953 	u_char  requested_s_scale;
954 	u_int32_t ts_recent;            /* timestamp echo data */
955 
956 	u_int32_t ts_recent_age;        /* when last updated */
957 	tcp_seq last_ack_sent;
958 /* RFC 1644 variables */
959 	tcp_cc  cc_send;                /* send connection count */
960 	tcp_cc  cc_recv;                /* receive connection count */
961 	tcp_seq snd_recover;            /* for use in fast recovery */
962 /* experimental */
963 	u_int32_t snd_cwnd_prev;        /* cwnd prior to retransmit */
964 	u_int32_t snd_ssthresh_prev;    /* ssthresh prior to retransmit */
965 	u_int32_t t_badrxtwin;          /* window for retransmit recovery */
966 };
967 
968 #define        tcps_ecn_setup  tcps_ecn_client_success
969 #define        tcps_sent_cwr   tcps_ecn_recv_ece
970 #define        tcps_sent_ece   tcps_ecn_sent_ece
971 
972 /*
973  * TCP statistics.
974  * Many of these should be kept per connection,
975  * but that's inconvenient at the moment.
976  */
977 struct  tcpstat {
978 	u_int32_t       tcps_connattempt;       /* connections initiated */
979 	u_int32_t       tcps_accepts;           /* connections accepted */
980 	u_int32_t       tcps_connects;          /* connections established */
981 	u_int32_t       tcps_drops;             /* connections dropped */
982 	u_int32_t       tcps_conndrops;         /* embryonic connections dropped */
983 	u_int32_t       tcps_closed;            /* conn. closed (includes drops) */
984 	u_int32_t       tcps_segstimed;         /* segs where we tried to get rtt */
985 	u_int32_t       tcps_rttupdated;        /* times we succeeded */
986 	u_int32_t       tcps_delack;            /* delayed acks sent */
987 	u_int32_t       tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
988 	u_int32_t       tcps_rexmttimeo;        /* retransmit timeouts */
989 	u_int32_t       tcps_persisttimeo;      /* persist timeouts */
990 	u_int32_t       tcps_keeptimeo;         /* keepalive timeouts */
991 	u_int32_t       tcps_keepprobe;         /* keepalive probes sent */
992 	u_int32_t       tcps_keepdrops;         /* connections dropped in keepalive */
993 
994 	u_int32_t       tcps_sndtotal;          /* total packets sent */
995 	u_int32_t       tcps_sndpack;           /* data packets sent */
996 	u_int32_t       tcps_sndbyte;           /* data bytes sent */
997 	u_int32_t       tcps_sndrexmitpack;     /* data packets retransmitted */
998 	u_int32_t       tcps_sndrexmitbyte;     /* data bytes retransmitted */
999 	u_int32_t       tcps_sndacks;           /* ack-only packets sent */
1000 	u_int32_t       tcps_sndprobe;          /* window probes sent */
1001 	u_int32_t       tcps_sndurg;            /* packets sent with URG only */
1002 	u_int32_t       tcps_sndwinup;          /* window update-only packets sent */
1003 	u_int32_t       tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
1004 
1005 	u_int32_t       tcps_rcvtotal;          /* total packets received */
1006 	u_int32_t       tcps_rcvpack;           /* packets received in sequence */
1007 	u_int32_t       tcps_rcvbyte;           /* bytes received in sequence */
1008 	u_int32_t       tcps_rcvbadsum;         /* packets received with ccksum errs */
1009 	u_int32_t       tcps_rcvbadoff;         /* packets received with bad offset */
1010 	u_int32_t       tcps_rcvmemdrop;        /* packets dropped for lack of memory */
1011 	u_int32_t       tcps_rcvshort;          /* packets received too short */
1012 	u_int32_t       tcps_rcvduppack;        /* duplicate-only packets received */
1013 	u_int32_t       tcps_rcvdupbyte;        /* duplicate-only bytes received */
1014 	u_int32_t       tcps_rcvpartduppack;    /* packets with some duplicate data */
1015 	u_int32_t       tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
1016 	u_int32_t       tcps_rcvoopack;         /* out-of-order packets received */
1017 	u_int32_t       tcps_rcvoobyte;         /* out-of-order bytes received */
1018 	u_int32_t       tcps_rcvpackafterwin;   /* packets with data after window */
1019 	u_int32_t       tcps_rcvbyteafterwin;   /* bytes rcvd after window */
1020 	u_int32_t       tcps_rcvafterclose;     /* packets rcvd after "close" */
1021 	u_int32_t       tcps_rcvwinprobe;       /* rcvd window probe packets */
1022 	u_int32_t       tcps_rcvdupack;         /* rcvd duplicate acks */
1023 	u_int32_t       tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
1024 	u_int32_t       tcps_rcvackpack;        /* rcvd ack packets */
1025 	u_int32_t       tcps_rcvackbyte;        /* bytes acked by rcvd acks */
1026 	u_int32_t       tcps_rcvwinupd;         /* rcvd window update packets */
1027 	u_int32_t       tcps_pawsdrop;          /* segments dropped due to PAWS */
1028 	u_int32_t       tcps_predack;           /* times hdr predict ok for acks */
1029 	u_int32_t       tcps_preddat;           /* times hdr predict ok for data pkts */
1030 	u_int32_t       tcps_pcbcachemiss;
1031 	u_int32_t       tcps_cachedrtt;         /* times cached RTT in route updated */
1032 	u_int32_t       tcps_cachedrttvar;      /* times cached rttvar updated */
1033 	u_int32_t       tcps_cachedssthresh;    /* times cached ssthresh updated */
1034 	u_int32_t       tcps_usedrtt;           /* times RTT initialized from route */
1035 	u_int32_t       tcps_usedrttvar;        /* times RTTVAR initialized from rt */
1036 	u_int32_t       tcps_usedssthresh;      /* times ssthresh initialized from rt*/
1037 	u_int32_t       tcps_persistdrop;       /* timeout in persist state */
1038 	u_int32_t       tcps_badsyn;            /* bogus SYN, e.g. premature ACK */
1039 	u_int32_t       tcps_mturesent;         /* resends due to MTU discovery */
1040 	u_int32_t       tcps_listendrop;        /* listen queue overflows */
1041 	u_int32_t       tcps_synchallenge;      /* challenge ACK due to bad SYN */
1042 	u_int32_t       tcps_rstchallenge;      /* challenge ACK due to bad RST */
1043 
1044 	/* new stats from FreeBSD 5.4 sync up */
1045 	u_int32_t       tcps_minmssdrops;       /* average minmss too low drops */
1046 
1047 	u_int32_t       tcps_sndrexmitbad;      /* unnecessary packet retransmissions */
1048 	u_int32_t       tcps_badrst;            /* ignored RSTs in the window */
1049 
1050 	u_int32_t       tcps_sc_added;          /* entry added to syncache */
1051 	u_int32_t       tcps_sc_retransmitted;  /* syncache entry was retransmitted */
1052 	u_int32_t       tcps_sc_dupsyn;         /* duplicate SYN packet */
1053 	u_int32_t       tcps_sc_dropped;        /* could not reply to packet */
1054 	u_int32_t       tcps_sc_completed;      /* successful extraction of entry */
1055 	u_int32_t       tcps_sc_bucketoverflow; /* syncache per-bucket limit hit */
1056 	u_int32_t       tcps_sc_cacheoverflow;  /* syncache cache limit hit */
1057 	u_int32_t       tcps_sc_reset;          /* RST removed entry from syncache */
1058 	u_int32_t       tcps_sc_stale;          /* timed out or listen socket gone */
1059 	u_int32_t       tcps_sc_aborted;        /* syncache entry aborted */
1060 	u_int32_t       tcps_sc_badack;         /* removed due to bad ACK */
1061 	u_int32_t       tcps_sc_unreach;        /* ICMP unreachable received */
1062 	u_int32_t       tcps_sc_zonefail;       /* zalloc() failed */
1063 	u_int32_t       tcps_sc_sendcookie;     /* SYN cookie sent */
1064 	u_int32_t       tcps_sc_recvcookie;     /* SYN cookie received */
1065 
1066 	u_int32_t       tcps_hc_added;          /* entry added to hostcache */
1067 	u_int32_t       tcps_hc_bucketoverflow; /* hostcache per bucket limit hit */
1068 
1069 	/* SACK related stats */
1070 	u_int32_t       tcps_sack_recovery_episode; /* SACK recovery episodes */
1071 	u_int32_t       tcps_sack_rexmits;          /* SACK rexmit segments   */
1072 	u_int32_t       tcps_sack_rexmit_bytes;     /* SACK rexmit bytes      */
1073 	u_int32_t       tcps_sack_rcv_blocks;       /* SACK blocks (options) received */
1074 	u_int32_t       tcps_sack_send_blocks;      /* SACK blocks (options) sent     */
1075 	u_int32_t       tcps_sack_sboverflow;       /* SACK sendblock overflow   */
1076 
1077 	u_int32_t       tcps_bg_rcvtotal;       /* total background packets received */
1078 	u_int32_t       tcps_rxtfindrop;        /* drop conn after retransmitting FIN */
1079 	u_int32_t       tcps_fcholdpacket;      /* packets withheld because of flow control */
1080 
1081 	u_int32_t       tcps_limited_txt;       /* Limited transmit used */
1082 	u_int32_t       tcps_early_rexmt;       /* Early retransmit used */
1083 	u_int32_t       tcps_sack_ackadv;       /* Cumulative ack advanced along with sack */
1084 
1085 	/* Checksum related stats */
1086 	u_int32_t       tcps_rcv_swcsum;        /* tcp swcksum (inbound), packets */
1087 	u_int32_t       tcps_rcv_swcsum_bytes;  /* tcp swcksum (inbound), bytes */
1088 	u_int32_t       tcps_rcv6_swcsum;       /* tcp6 swcksum (inbound), packets */
1089 	u_int32_t       tcps_rcv6_swcsum_bytes; /* tcp6 swcksum (inbound), bytes */
1090 	u_int32_t       tcps_snd_swcsum;        /* tcp swcksum (outbound), packets */
1091 	u_int32_t       tcps_snd_swcsum_bytes;  /* tcp swcksum (outbound), bytes */
1092 	u_int32_t       tcps_snd6_swcsum;       /* tcp6 swcksum (outbound), packets */
1093 	u_int32_t       tcps_snd6_swcsum_bytes; /* tcp6 swcksum (outbound), bytes */
1094 	u_int32_t       tcps_unused_1;
1095 	u_int32_t       tcps_unused_2;
1096 	u_int32_t       tcps_unused_3;
1097 
1098 	/* MPTCP Related stats */
1099 	u_int32_t       tcps_invalid_mpcap;     /* Invalid MPTCP capable opts */
1100 	u_int32_t       tcps_invalid_joins;     /* Invalid MPTCP joins */
1101 	u_int32_t       tcps_mpcap_fallback;    /* TCP fallback in primary */
1102 	u_int32_t       tcps_join_fallback;     /* No MPTCP in secondary */
1103 	u_int32_t       tcps_estab_fallback;    /* DSS option dropped */
1104 	u_int32_t       tcps_invalid_opt;       /* Catchall error stat */
1105 	u_int32_t       tcps_mp_outofwin;       /* Packet lies outside the
1106 	                                         *  shared recv window */
1107 	u_int32_t       tcps_mp_reducedwin;     /* Reduced subflow window */
1108 	u_int32_t       tcps_mp_badcsum;        /* Bad DSS csum */
1109 	u_int32_t       tcps_mp_oodata;         /* Out of order data */
1110 	u_int32_t       tcps_mp_switches;       /* number of subflow switch */
1111 	u_int32_t       tcps_mp_rcvtotal;       /* number of rcvd packets */
1112 	u_int32_t       tcps_mp_rcvbytes;       /* number of bytes received */
1113 	u_int32_t       tcps_mp_sndpacks;       /* number of data packs sent */
1114 	u_int32_t       tcps_mp_sndbytes;       /* number of bytes sent */
1115 	u_int32_t       tcps_join_rxmts;        /* join ack retransmits */
1116 	u_int32_t       tcps_tailloss_rto;      /* RTO due to tail loss */
1117 	u_int32_t       tcps_reordered_pkts;    /* packets reorderd */
1118 	u_int32_t       tcps_recovered_pkts;    /* recovered after loss */
1119 	u_int32_t       tcps_pto;               /* probe timeout */
1120 	u_int32_t       tcps_rto_after_pto;     /* RTO after a probe */
1121 	u_int32_t       tcps_tlp_recovery;      /* TLP induced fast recovery */
1122 	u_int32_t       tcps_tlp_recoverlastpkt; /* TLP recoverd last pkt */
1123 	u_int32_t       tcps_ecn_client_success; /* client-side connection negotiated ECN */
1124 	u_int32_t       tcps_ecn_recv_ece;      /* ECE received, sent CWR */
1125 	u_int32_t       tcps_ecn_sent_ece;      /* Sent ECE notification */
1126 	u_int32_t       tcps_detect_reordering; /* Detect pkt reordering */
1127 	u_int32_t       tcps_delay_recovery;    /* Delay fast recovery */
1128 	u_int32_t       tcps_avoid_rxmt;        /* Retransmission was avoided */
1129 	u_int32_t       tcps_unnecessary_rxmt;  /* Retransmission was not needed */
1130 	u_int32_t       tcps_nostretchack;      /* disabled stretch ack algorithm on a connection */
1131 	u_int32_t       tcps_rescue_rxmt;       /* SACK rescue retransmit */
1132 	u_int32_t       tcps_pto_in_recovery;   /* rescue retransmit in fast recovery */
1133 	u_int32_t       tcps_pmtudbh_reverted;  /* PMTU Blackhole detection, segment size reverted */
1134 
1135 	/* DSACK related statistics */
1136 	u_int32_t       tcps_dsack_disable;     /* DSACK disabled due to n/w duplication */
1137 	u_int32_t       tcps_dsack_ackloss;     /* ignore DSACK due to ack loss */
1138 	u_int32_t       tcps_dsack_badrexmt;    /* DSACK based bad rexmt recovery */
1139 	u_int32_t       tcps_dsack_sent;        /* Sent DSACK notification */
1140 	u_int32_t       tcps_dsack_recvd;       /* Received a valid DSACK option */
1141 	u_int32_t       tcps_dsack_recvd_old;   /* Received an out of window DSACK option */
1142 
1143 	/* MPTCP Subflow selection stats */
1144 	u_int32_t       tcps_mp_sel_symtomsd;   /* By symptomsd */
1145 	u_int32_t       tcps_mp_sel_rtt;        /* By RTT comparison */
1146 	u_int32_t       tcps_mp_sel_rto;        /* By RTO comparison */
1147 	u_int32_t       tcps_mp_sel_peer;       /* By peer's output pattern */
1148 	u_int32_t       tcps_mp_num_probes;     /* Number of probes sent */
1149 	u_int32_t       tcps_mp_verdowngrade;   /* MPTCP version downgrade */
1150 	u_int32_t       tcps_drop_after_sleep;  /* drop after long AP sleep */
1151 	u_int32_t       tcps_probe_if;          /* probe packets after interface availability */
1152 	u_int32_t       tcps_probe_if_conflict; /* Can't send probe packets for interface */
1153 
1154 	u_int32_t       tcps_ecn_client_setup;  /* Attempted ECN setup from client side */
1155 	u_int32_t       tcps_ecn_server_setup;  /* Attempted ECN setup from server side */
1156 	u_int32_t       tcps_ecn_server_success; /* server-side connection negotiated ECN */
1157 	u_int32_t       tcps_ecn_lost_synack;   /* Lost SYN-ACK with ECN setup */
1158 	u_int32_t       tcps_ecn_lost_syn;      /* Lost SYN with ECN setup */
1159 	u_int32_t       tcps_ecn_not_supported; /* Server did not support ECN setup */
1160 	u_int32_t       tcps_ecn_recv_ce;       /* Received CE from the network */
1161 	u_int32_t       tcps_ecn_conn_recv_ce;  /* Number of connections received CE atleast once */
1162 	u_int32_t       tcps_ecn_conn_recv_ece; /* Number of connections received ECE atleast once */
1163 	u_int32_t       tcps_ecn_conn_plnoce;   /* Number of connections that received no CE and sufferred packet loss */
1164 	u_int32_t       tcps_ecn_conn_pl_ce;    /* Number of connections that received CE and sufferred packet loss */
1165 	u_int32_t       tcps_ecn_conn_nopl_ce;  /* Number of connections that received CE and sufferred no packet loss */
1166 	u_int32_t       tcps_ecn_fallback_synloss; /* Number of times we did fall back due to SYN-Loss */
1167 	u_int32_t       tcps_ecn_fallback_reorder; /* Number of times we fallback because we detected the PAWS-issue */
1168 	u_int32_t       tcps_ecn_fallback_ce;   /* Number of times we fallback because we received too many CEs */
1169 
1170 	/* TFO-related statistics */
1171 	u_int32_t       tcps_tfo_syn_data_rcv;  /* Received a SYN+data with valid cookie */
1172 	u_int32_t       tcps_tfo_cookie_req_rcv;/* Received a TFO cookie-request */
1173 	u_int32_t       tcps_tfo_cookie_sent;   /* Offered a TFO-cookie to the client */
1174 	u_int32_t       tcps_tfo_cookie_invalid;/* Received an invalid TFO-cookie */
1175 	u_int32_t       tcps_tfo_cookie_req;    /* Cookie requested with the SYN */
1176 	u_int32_t       tcps_tfo_cookie_rcv;    /* Cookie received in a SYN/ACK */
1177 	u_int32_t       tcps_tfo_syn_data_sent; /* SYN+data+cookie sent */
1178 	u_int32_t       tcps_tfo_syn_data_acked;/* SYN+data has been acknowledged */
1179 	u_int32_t       tcps_tfo_syn_loss;      /* SYN+TFO has been lost and we fallback */
1180 	u_int32_t       tcps_tfo_blackhole;     /* TFO got blackholed by a middlebox. */
1181 	u_int32_t       tcps_tfo_cookie_wrong;  /* TFO-cookie we sent was wrong */
1182 	u_int32_t       tcps_tfo_no_cookie_rcv; /* We asked for a cookie but didn't get one */
1183 	u_int32_t       tcps_tfo_heuristics_disable; /* TFO got disabled due to heuristics */
1184 	u_int32_t       tcps_tfo_sndblackhole;  /* TFO got blackholed in the sending direction */
1185 	u_int32_t       tcps_mss_to_default;    /* Change MSS to default using link status report */
1186 	u_int32_t       tcps_mss_to_medium;     /* Change MSS to medium using link status report */
1187 	u_int32_t       tcps_mss_to_low;        /* Change MSS to low using link status report */
1188 	u_int32_t       tcps_ecn_fallback_droprst; /* ECN fallback caused by connection drop due to RST */
1189 	u_int32_t       tcps_ecn_fallback_droprxmt; /* ECN fallback due to drop after multiple retransmits */
1190 	u_int32_t       tcps_ecn_fallback_synrst; /* ECN fallback due to rst after syn */
1191 
1192 	u_int32_t       tcps_mptcp_rcvmemdrop;  /* MPTCP packets dropped for lack of memory */
1193 	u_int32_t       tcps_mptcp_rcvduppack;  /* MPTCP duplicate-only packets received */
1194 	u_int32_t       tcps_mptcp_rcvpackafterwin; /* MPTCP packets with data after window */
1195 
1196 	/* TCP timer statistics */
1197 	u_int32_t       tcps_timer_drift_le_1_ms;       /* Timer drift less or equal to 1 ms */
1198 	u_int32_t       tcps_timer_drift_le_10_ms;      /* Timer drift less or equal to 10 ms */
1199 	u_int32_t       tcps_timer_drift_le_20_ms;      /* Timer drift less or equal to 20 ms */
1200 	u_int32_t       tcps_timer_drift_le_50_ms;      /* Timer drift less or equal to 50 ms */
1201 	u_int32_t       tcps_timer_drift_le_100_ms;     /* Timer drift less or equal to 100 ms */
1202 	u_int32_t       tcps_timer_drift_le_200_ms;     /* Timer drift less or equal to 200 ms */
1203 	u_int32_t       tcps_timer_drift_le_500_ms;     /* Timer drift less or equal to 500 ms */
1204 	u_int32_t       tcps_timer_drift_le_1000_ms;    /* Timer drift less or equal to 1000 ms */
1205 	u_int32_t       tcps_timer_drift_gt_1000_ms;    /* Timer drift greater than 1000 ms */
1206 
1207 	u_int32_t       tcps_mptcp_handover_attempt;    /* Total number of MPTCP-attempts using handover mode */
1208 	u_int32_t       tcps_mptcp_interactive_attempt; /* Total number of MPTCP-attempts using interactive mode */
1209 	u_int32_t       tcps_mptcp_aggregate_attempt;   /* Total number of MPTCP-attempts using aggregate mode */
1210 	u_int32_t       tcps_mptcp_fp_handover_attempt; /* Same as previous three but only for first-party apps */
1211 	u_int32_t       tcps_mptcp_fp_interactive_attempt;
1212 	u_int32_t       tcps_mptcp_fp_aggregate_attempt;
1213 	u_int32_t       tcps_mptcp_heuristic_fallback;  /* Total number of MPTCP-connections that fell back due to heuristics */
1214 	u_int32_t       tcps_mptcp_fp_heuristic_fallback;       /* Same as previous but for first-party apps */
1215 	u_int32_t       tcps_mptcp_handover_success_wifi;       /* Total number of successfull handover-mode connections that *started* on WiFi */
1216 	u_int32_t       tcps_mptcp_handover_success_cell;       /* Total number of successfull handover-mode connections that *started* on Cell */
1217 	u_int32_t       tcps_mptcp_interactive_success;         /* Total number of interactive-mode connections that negotiated MPTCP */
1218 	u_int32_t       tcps_mptcp_aggregate_success;           /* Same as previous but for aggregate */
1219 	u_int32_t       tcps_mptcp_fp_handover_success_wifi;    /* Same as previous four, but for first-party apps */
1220 	u_int32_t       tcps_mptcp_fp_handover_success_cell;
1221 	u_int32_t       tcps_mptcp_fp_interactive_success;
1222 	u_int32_t       tcps_mptcp_fp_aggregate_success;
1223 	u_int32_t       tcps_mptcp_handover_cell_from_wifi;     /* Total number of connections that use cell in handover-mode (coming from WiFi) */
1224 	u_int32_t       tcps_mptcp_handover_wifi_from_cell;     /* Total number of connections that use WiFi in handover-mode (coming from cell) */
1225 	u_int32_t       tcps_mptcp_interactive_cell_from_wifi;  /* Total number of connections that use cell in interactive mode (coming from WiFi) */
1226 	u_int64_t       tcps_mptcp_handover_cell_bytes;         /* Total number of bytes sent on cell in handover-mode (on new subflows, ignoring initial one) */
1227 	u_int64_t       tcps_mptcp_interactive_cell_bytes;      /* Same as previous but for interactive */
1228 	u_int64_t       tcps_mptcp_aggregate_cell_bytes;
1229 	u_int64_t       tcps_mptcp_handover_all_bytes;          /* Total number of bytes sent in handover */
1230 	u_int64_t       tcps_mptcp_interactive_all_bytes;
1231 	u_int64_t       tcps_mptcp_aggregate_all_bytes;
1232 	u_int32_t       tcps_mptcp_back_to_wifi;        /* Total number of connections that succeed to move traffic away from cell (when starting on cell) */
1233 	u_int32_t       tcps_mptcp_wifi_proxy;          /* Total number of new subflows that fell back to regular TCP on cell */
1234 	u_int32_t       tcps_mptcp_cell_proxy;          /* Total number of new subflows that fell back to regular TCP on WiFi */
1235 
1236 	/* TCP offload statistics */
1237 	u_int32_t       tcps_ka_offload_drops;  /* Keep alive drops for timeout reported by firmware */
1238 
1239 	u_int32_t       tcps_mptcp_triggered_cell;      /* Total number of times an MPTCP-connection triggered cell bringup */
1240 
1241 	u_int32_t       tcps_fin_timeout_drops;
1242 };
1243 
1244 
1245 struct tcpstat_local {
1246 	u_int64_t badformat;
1247 	u_int64_t unspecv6;
1248 	u_int64_t synfin;
1249 	u_int64_t badformatipsec;
1250 	u_int64_t noconnnolist;
1251 	u_int64_t noconnlist;
1252 	u_int64_t listbadsyn;
1253 	u_int64_t icmp6unreach;
1254 	u_int64_t deprecate6;
1255 	u_int64_t ooopacket;
1256 	u_int64_t rstinsynrcv;
1257 	u_int64_t dospacket;
1258 	u_int64_t cleanup;
1259 	u_int64_t synwindow;
1260 };
1261 
1262 #pragma pack(4)
1263 
1264 /*
1265  * TCB structure exported to user-land via sysctl(3).
1266  * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
1267  * included.  Not all of our clients do.
1268  */
1269 
1270 struct  xtcpcb {
1271 	u_int32_t       xt_len;
1272 #ifdef KERNEL_PRIVATE
1273 	struct  inpcb_compat    xt_inp;
1274 #else
1275 	struct  inpcb   xt_inp;
1276 #endif
1277 #ifdef KERNEL_PRIVATE
1278 	struct  otcpcb  xt_tp;
1279 #else
1280 	struct  tcpcb   xt_tp;
1281 #endif
1282 	struct  xsocket xt_socket;
1283 	u_quad_t        xt_alignment_hack;
1284 };
1285 
1286 #if XNU_TARGET_OS_OSX || KERNEL || !(TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR)
1287 
1288 struct  xtcpcb64 {
1289 	u_int32_t               xt_len;
1290 	struct xinpcb64         xt_inpcb;
1291 
1292 	u_int64_t t_segq;
1293 	int     t_dupacks;              /* consecutive dup acks recd */
1294 
1295 	int t_timer[TCPT_NTIMERS_EXT];  /* tcp timers */
1296 
1297 	int     t_state;                /* state of this connection */
1298 	u_int   t_flags;
1299 
1300 	int     t_force;                /* 1 if forcing out a byte */
1301 
1302 	tcp_seq snd_una;                /* send unacknowledged */
1303 	tcp_seq snd_max;                /* highest sequence number sent;
1304 	                                 * used to recognize retransmits
1305 	                                 */
1306 	tcp_seq snd_nxt;                /* send next */
1307 	tcp_seq snd_up;                 /* send urgent pointer */
1308 
1309 	tcp_seq snd_wl1;                /* window update seg seq number */
1310 	tcp_seq snd_wl2;                /* window update seg ack number */
1311 	tcp_seq iss;                    /* initial send sequence number */
1312 	tcp_seq irs;                    /* initial receive sequence number */
1313 
1314 	tcp_seq rcv_nxt;                /* receive next */
1315 	tcp_seq rcv_adv;                /* advertised window */
1316 	u_int32_t rcv_wnd;              /* receive window */
1317 	tcp_seq rcv_up;                 /* receive urgent pointer */
1318 
1319 	u_int32_t snd_wnd;              /* send window */
1320 	u_int32_t snd_cwnd;             /* congestion-controlled window */
1321 	u_int32_t snd_ssthresh;         /* snd_cwnd size threshold for
1322 	                                 * for slow start exponential to
1323 	                                 * linear switch
1324 	                                 */
1325 	u_int   t_maxopd;               /* mss plus options */
1326 
1327 	u_int32_t t_rcvtime;            /* time at which a packet was received */
1328 	u_int32_t t_starttime;          /* time connection was established */
1329 	int     t_rtttime;              /* round trip time */
1330 	tcp_seq t_rtseq;                /* sequence number being timed */
1331 
1332 	int     t_rxtcur;               /* current retransmit value (ticks) */
1333 	u_int   t_maxseg;               /* maximum segment size */
1334 	int     t_srtt;                 /* smoothed round-trip time */
1335 	int     t_rttvar;               /* variance in round-trip time */
1336 
1337 	int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
1338 	u_int   t_rttmin;               /* minimum rtt allowed */
1339 	u_int32_t t_rttupdated;         /* number of times rtt sampled */
1340 	u_int32_t max_sndwnd;           /* largest window peer has offered */
1341 
1342 	int     t_softerror;            /* possible error not yet reported */
1343 /* out-of-band data */
1344 	char    t_oobflags;             /* have some */
1345 	char    t_iobc;                 /* input character */
1346 /* RFC 1323 variables */
1347 	u_char  snd_scale;              /* window scaling for send window */
1348 	u_char  rcv_scale;              /* window scaling for recv window */
1349 	u_char  request_r_scale;        /* pending window scaling */
1350 	u_char  requested_s_scale;
1351 	u_int32_t ts_recent;            /* timestamp echo data */
1352 
1353 	u_int32_t ts_recent_age;        /* when last updated */
1354 	tcp_seq last_ack_sent;
1355 /* RFC 1644 variables */
1356 	tcp_cc  cc_send;                /* send connection count */
1357 	tcp_cc  cc_recv;                /* receive connection count */
1358 	tcp_seq snd_recover;            /* for use in fast recovery */
1359 /* experimental */
1360 	u_int32_t snd_cwnd_prev;        /* cwnd prior to retransmit */
1361 	u_int32_t snd_ssthresh_prev;    /* ssthresh prior to retransmit */
1362 	u_int32_t t_badrxtwin;          /* window for retransmit recovery */
1363 
1364 	u_quad_t                xt_alignment_hack;
1365 };
1366 
1367 #endif /* XNU_TARGET_OS_OSX || KERNEL || !(TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR) */
1368 
1369 #ifdef PRIVATE
1370 
1371 struct  xtcpcb_n {
1372 	u_int32_t               xt_len;
1373 	u_int32_t                       xt_kind;                /* XSO_TCPCB */
1374 
1375 	u_int64_t t_segq;
1376 	int     t_dupacks;              /* consecutive dup acks recd */
1377 
1378 	int t_timer[TCPT_NTIMERS_EXT];  /* tcp timers */
1379 
1380 	int     t_state;                /* state of this connection */
1381 	u_int   t_flags;
1382 
1383 	int     t_force;                /* 1 if forcing out a byte */
1384 
1385 	tcp_seq snd_una;                /* send unacknowledged */
1386 	tcp_seq snd_max;                /* highest sequence number sent;
1387 	                                 * used to recognize retransmits
1388 	                                 */
1389 	tcp_seq snd_nxt;                /* send next */
1390 	tcp_seq snd_up;                 /* send urgent pointer */
1391 
1392 	tcp_seq snd_wl1;                /* window update seg seq number */
1393 	tcp_seq snd_wl2;                /* window update seg ack number */
1394 	tcp_seq iss;                    /* initial send sequence number */
1395 	tcp_seq irs;                    /* initial receive sequence number */
1396 
1397 	tcp_seq rcv_nxt;                /* receive next */
1398 	tcp_seq rcv_adv;                /* advertised window */
1399 	u_int32_t rcv_wnd;              /* receive window */
1400 	tcp_seq rcv_up;                 /* receive urgent pointer */
1401 
1402 	u_int32_t snd_wnd;              /* send window */
1403 	u_int32_t snd_cwnd;             /* congestion-controlled window */
1404 	u_int32_t snd_ssthresh;         /* snd_cwnd size threshold for
1405 	                                 * for slow start exponential to
1406 	                                 * linear switch
1407 	                                 */
1408 	u_int   t_maxopd;               /* mss plus options */
1409 
1410 	u_int32_t t_rcvtime;            /* time at which a packet was received */
1411 	u_int32_t t_starttime;          /* time connection was established */
1412 	int     t_rtttime;              /* round trip time */
1413 	tcp_seq t_rtseq;                /* sequence number being timed */
1414 
1415 	int     t_rxtcur;               /* current retransmit value (ticks) */
1416 	u_int   t_maxseg;               /* maximum segment size */
1417 	int     t_srtt;                 /* smoothed round-trip time */
1418 	int     t_rttvar;               /* variance in round-trip time */
1419 
1420 	int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
1421 	u_int   t_rttmin;               /* minimum rtt allowed */
1422 	u_int32_t t_rttupdated;         /* number of times rtt sampled */
1423 	u_int32_t max_sndwnd;           /* largest window peer has offered */
1424 
1425 	int     t_softerror;            /* possible error not yet reported */
1426 	/* out-of-band data */
1427 	char    t_oobflags;             /* have some */
1428 	char    t_iobc;                 /* input character */
1429 	/* RFC 1323 variables */
1430 	u_char  snd_scale;              /* window scaling for send window */
1431 	u_char  rcv_scale;              /* window scaling for recv window */
1432 	u_char  request_r_scale;        /* pending window scaling */
1433 	u_char  requested_s_scale;
1434 	u_int32_t ts_recent;            /* timestamp echo data */
1435 
1436 	u_int32_t ts_recent_age;        /* when last updated */
1437 	tcp_seq last_ack_sent;
1438 	/* RFC 1644 variables */
1439 	tcp_cc  cc_send;                /* send connection count */
1440 	tcp_cc  cc_recv;                /* receive connection count */
1441 	tcp_seq snd_recover;            /* for use in fast recovery */
1442 	/* experimental */
1443 	u_int32_t snd_cwnd_prev;        /* cwnd prior to retransmit */
1444 	u_int32_t snd_ssthresh_prev;    /* ssthresh prior to retransmit */
1445 };
1446 
1447 /*
1448  * The rtt measured is in milliseconds as the timestamp granularity is
1449  * a millisecond. The smoothed round-trip time and estimated variance
1450  * are stored as fixed point numbers scaled by the values below.
1451  * For convenience, these scales are also used in smoothing the average
1452  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
1453  * With these scales, srtt has 5 bits to the right of the binary point,
1454  * and thus an "ALPHA" of 0.875.  rttvar has 4 bits to the right of the
1455  * binary point, and is smoothed with an ALPHA of 0.75.
1456  */
1457 #define TCP_RTT_SCALE           32      /* multiplier for srtt; 3 bits frac. */
1458 #define TCP_RTT_SHIFT           5       /* shift for srtt; 5 bits frac. */
1459 #define TCP_RTTVAR_SCALE        16      /* multiplier for rttvar; 4 bits */
1460 #define TCP_RTTVAR_SHIFT        4       /* shift for rttvar; 4 bits */
1461 #define TCP_DELTA_SHIFT         2       /* see tcp_input.c */
1462 
1463 
1464 /*
1465  * TCP structure with information that gives insight into forward progress on an interface,
1466  * exported to user-land via sysctl(3).
1467  */
1468 struct  xtcpprogress_indicators {
1469 	u_int32_t       xp_numflows;            /* Total number of flows */
1470 	u_int32_t       xp_conn_probe_fails;    /* Count of connection failures */
1471 	u_int32_t       xp_read_probe_fails;    /* Count of read probe failures */
1472 	u_int32_t       xp_write_probe_fails;   /* Count of write failures */
1473 	u_int32_t       xp_recentflows;         /* Total of "recent" flows */
1474 	u_int32_t       xp_recentflows_unacked; /* Total of "recent" flows with unacknowledged data */
1475 	u_int64_t       xp_recentflows_rxbytes; /* Total of "recent" flows received bytes */
1476 	u_int64_t       xp_recentflows_txbytes; /* Total of "recent" flows transmitted bytes */
1477 	u_int64_t       xp_recentflows_rxooo;   /* Total of "recent" flows received out of order bytes */
1478 	u_int64_t       xp_recentflows_rxdup;   /* Total of "recent" flows received duplicate bytes */
1479 	u_int64_t       xp_recentflows_retx;    /* Total of "recent" flows retransmitted bytes */
1480 	u_int64_t       xp_reserved1;           /* Expansion */
1481 	u_int64_t       xp_reserved2;           /* Expansion */
1482 	u_int64_t       xp_reserved3;           /* Expansion */
1483 	u_int64_t       xp_reserved4;           /* Expansion */
1484 };
1485 
1486 struct tcpprogressreq {
1487 	u_int64_t       ifindex;                /* Interface index for progress indicators */
1488 	u_int64_t       recentflow_maxduration; /* In mach_absolute_time, max duration for flow to be counted as "recent" */
1489 	u_int64_t       filter_flags;           /* Optional additional filtering, values are interface properties per ntstat.h */
1490 	u_int64_t       xp_reserved2;           /* Expansion */
1491 };
1492 
1493 struct tcpprobereq {
1494 	u_int64_t       ifindex;                /* Optional interface index for TCP keep-alive probing */
1495 	u_int64_t       enable;                 /* Flag to enable or disable probing (1=on, 0=off)*/
1496 	u_int64_t       filter_flags;           /* Optional flags for filtering interfaces per ntstat.h (NSTAT_IFNET_IS_*) */
1497 	u_int32_t       reserved;               /* Expansion */
1498 	u_int32_t       reserved2;              /* Expansion */
1499 };
1500 
1501 #endif /* PRIVATE */
1502 
1503 #pragma pack()
1504 
1505 /*
1506  * Names for TCP sysctl objects
1507  */
1508 #define TCPCTL_DO_RFC1323       1       /* use RFC-1323 extensions */
1509 #define TCPCTL_DO_RFC1644       2       /* use RFC-1644 extensions */
1510 #define TCPCTL_MSSDFLT          3       /* MSS default */
1511 #define TCPCTL_STATS            4       /* statistics (read-only) */
1512 #define TCPCTL_RTTDFLT          5       /* default RTT estimate */
1513 #define TCPCTL_KEEPIDLE         6       /* keepalive idle timer */
1514 #define TCPCTL_KEEPINTVL        7       /* interval to send keepalives */
1515 #define TCPCTL_SENDSPACE        8       /* send buffer space */
1516 #define TCPCTL_RECVSPACE        9       /* receive buffer space */
1517 #define TCPCTL_KEEPINIT         10      /* timeout for establishing syn */
1518 #define TCPCTL_PCBLIST          11      /* list of all outstanding PCBs */
1519 #define TCPCTL_DELACKTIME       12      /* time before sending delayed ACK */
1520 #define TCPCTL_V6MSSDFLT        13      /* MSS default for IPv6 */
1521 #define TCPCTL_MAXID            14
1522 
1523 #ifdef BSD_KERNEL_PRIVATE
1524 #include <sys/bitstring.h>
1525 
1526 #define TCP_PKTLIST_CLEAR(tp) {                                         \
1527 	(tp)->t_pktlist_head = (tp)->t_pktlist_tail = NULL;             \
1528 	(tp)->t_lastchain = (tp)->t_pktlist_sentlen = 0;                \
1529 }
1530 
1531 extern int tcp_TCPTV_MIN;
1532 
1533 #ifdef SYSCTL_DECL
1534 SYSCTL_DECL(_net_inet_tcp);
1535 #endif /* SYSCTL_DECL */
1536 
1537 extern  struct inpcbhead tcb;           /* head of queue of active tcpcb's */
1538 extern  struct inpcbinfo tcbinfo;
1539 extern  struct tcpstat tcpstat; /* tcp statistics */
1540 extern  int tcp_mssdflt;        /* XXX */
1541 extern  int tcp_minmss;
1542 #define TCP_FASTOPEN_SERVER 0x01
1543 #define TCP_FASTOPEN_CLIENT 0x02
1544 
1545 extern int tcp_tfo_halfcnt;
1546 extern int tcp_tfo_backlog;
1547 extern int tcp_fastopen;
1548 extern int ss_fltsz_local;
1549 extern int target_qdelay;
1550 extern u_int32_t tcp_now;               /* for RFC 1323 timestamps */
1551 extern struct timeval tcp_uptime;
1552 extern lck_spin_t tcp_uptime_lock;
1553 extern int tcp_delack_enabled;
1554 extern int maxseg_unacked;
1555 extern int tcp_use_newreno;
1556 extern int tcp_use_ledbat;
1557 extern struct zone *tcp_reass_zone;
1558 extern struct zone *tcp_rxt_seg_zone;
1559 extern int tcp_ecn_outbound;
1560 extern int tcp_ecn_inbound;
1561 extern uint32_t tcp_do_autorcvbuf;
1562 extern uint32_t tcp_autorcvbuf_max;
1563 extern int tcp_recv_bg;
1564 extern int tcp_do_ack_compression;
1565 extern int tcp_randomize_timestamps;
1566 extern int tcp_rledbat;
1567 extern int tcp_use_min_curr_rtt;
1568 /*
1569  * Dummy value used for when there is no flow and we want to ensure that compression
1570  * can happen.
1571  */
1572 #define TCP_ACK_COMPRESSION_DUMMY 1
1573 
1574 extern int tcp_do_better_lr;
1575 extern int tcp_cubic_minor_fixes;
1576 extern int tcp_cubic_rfc_compliant;
1577 extern int tcp_flow_control_response;
1578 
1579 extern int tcp_reass_total_qlen;
1580 
1581 struct protosw;
1582 struct domain;
1583 
1584 struct tcp_respond_args {
1585 	unsigned int ifscope;
1586 	unsigned int nocell:1,
1587 	    noexpensive:1,
1588 	    awdl_unrestricted:1,
1589 	    intcoproc_allowed:1,
1590 	    keep_alive:1,
1591 	    noconstrained:1;
1592 };
1593 
1594 void     tcp_canceltimers(struct tcpcb *);
1595 struct tcpcb *
1596 tcp_close(struct tcpcb *);
1597 void     tcp_ctlinput(int, struct sockaddr *, void *, struct ifnet *);
1598 int      tcp_ctloutput(struct socket *, struct sockopt *);
1599 struct tcpcb *
1600 tcp_drop(struct tcpcb *, int);
1601 void     tcp_drain(void);
1602 void     tcp_getrt_rtt(struct tcpcb *tp, struct rtentry *rt);
1603 void     tcp_init(struct protosw *, struct domain *);
1604 void     tcp_input(struct mbuf *, int);
1605 void     tcp_mss(struct tcpcb *, int, unsigned int);
1606 uint32_t tcp_ceil(double a);
1607 uint32_t tcp_round_to(uint32_t val, uint32_t round);
1608 uint32_t tcp_round_up(uint32_t val, uint32_t base);
1609 int      tcp_mssopt(struct tcpcb *);
1610 void     tcp_drop_syn_sent(struct inpcb *, int);
1611 void     tcp_mtudisc(struct inpcb *, int);
1612 struct tcpcb *
1613 tcp_newtcpcb(struct inpcb *);
1614 int      tcp_output(struct tcpcb *);
1615 void     tcp_respond(struct tcpcb *, void *, struct tcphdr *, struct mbuf *,
1616     tcp_seq, tcp_seq, uint8_t, struct tcp_respond_args *);
1617 struct rtentry *
1618 tcp_rtlookup(struct inpcb *, unsigned int);
1619 void     tcp_setpersist(struct tcpcb *);
1620 void     tcp_gc(struct inpcbinfo *);
1621 void     tcp_itimer(struct inpcbinfo *ipi);
1622 void     tcp_check_timer_state(struct tcpcb *tp);
1623 void     tcp_run_timerlist(void *arg1, void *arg2);
1624 void     tcp_sched_timers(struct tcpcb *tp);
1625 
1626 struct tcptemp *tcp_maketemplate(struct tcpcb *);
1627 void     tcp_fillheaders(struct mbuf *, struct tcpcb *, void *, void *);
1628 struct tcpcb *tcp_timers(struct tcpcb *, int);
1629 void     tcp_trace(int, int, struct tcpcb *, void *, struct tcphdr *, int);
1630 
1631 void tcp_fill_info(struct tcpcb *, struct tcp_info *);
1632 void tcp_sack_doack(struct tcpcb *, struct tcpopt *, struct tcphdr *,
1633     u_int32_t *, uint32_t *);
1634 extern boolean_t tcp_sack_process_dsack(struct tcpcb *, struct tcpopt *,
1635     struct tcphdr *);
1636 int tcp_detect_bad_rexmt(struct tcpcb *, struct tcphdr *, struct tcpopt *,
1637     u_int32_t rxtime);
1638 void     tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_laststart, tcp_seq rcv_lastend);
1639 void     tcp_clean_sackreport(struct tcpcb *tp);
1640 void     tcp_sack_adjust(struct tcpcb *tp);
1641 struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
1642 void     tcp_sack_partialack(struct tcpcb *, struct tcphdr *);
1643 void     tcp_free_sackholes(struct tcpcb *tp);
1644 void     tcp_sack_lost_rexmit(struct tcpcb *tp);
1645 int32_t  tcp_sbspace(struct tcpcb *tp);
1646 void     tcp_set_tso(struct tcpcb *tp, struct ifnet *ifp);
1647 void     tcp_set_ecn(struct tcpcb *tp, struct ifnet *ifp);
1648 int      tcp_flight_size(struct tcpcb *tp);
1649 void     tcp_reset_stretch_ack(struct tcpcb *tp);
1650 extern void tcp_get_ports_used(ifnet_t ifp, int, u_int32_t, bitstr_t *);
1651 uint32_t tcp_count_opportunistic(unsigned int ifindex, u_int32_t flags);
1652 uint32_t tcp_find_anypcb_byaddr(struct ifaddr *ifa);
1653 void tcp_set_max_rwinscale(struct tcpcb *tp, struct socket *so);
1654 struct bwmeas* tcp_bwmeas_alloc(struct tcpcb *tp);
1655 void tcp_bwmeas_free(struct tcpcb *tp);
1656 extern int32_t timer_diff(uint32_t t1, uint32_t toff1, uint32_t t2, uint32_t toff2);
1657 
1658 extern void tcp_set_background_cc(struct socket *);
1659 extern void tcp_set_foreground_cc(struct socket *);
1660 extern void tcp_set_recv_bg(struct socket *);
1661 extern void tcp_clear_recv_bg(struct socket *);
1662 extern boolean_t tcp_sack_byte_islost(struct tcpcb *tp);
1663 #define IS_TCP_RECV_BG(_so)     \
1664 	((_so)->so_flags1 & SOF1_TRAFFIC_MGT_TCP_RECVBG)
1665 
1666 #if TRAFFIC_MGT
1667 #define CLEAR_IAJ_STATE(_tp_) (_tp_)->iaj_rcv_ts = 0
1668 void     reset_acc_iaj(struct tcpcb *tp);
1669 #endif /* TRAFFIC_MGT */
1670 
1671 int      tcp_lock(struct socket *, int, void *);
1672 int      tcp_unlock(struct socket *, int, void *);
1673 void     calculate_tcp_clock(void);
1674 
1675 extern void tcp_keepalive_reset(struct tcpcb *);
1676 extern uint32_t get_base_rtt(struct tcpcb *tp);
1677 
1678 #ifdef _KERN_LOCKS_H_
1679 lck_mtx_t *      tcp_getlock(struct socket *, int);
1680 #else
1681 void *   tcp_getlock(struct socket *, int);
1682 #endif
1683 
1684 extern  struct pr_usrreqs tcp_usrreqs;
1685 extern  u_int32_t tcp_sendspace;
1686 extern  u_int32_t tcp_recvspace;
1687 tcp_seq tcp_new_isn(struct tcpcb *);
1688 
1689 extern int tcp_input_checksum(int, struct mbuf *, struct tcphdr *, int, int);
1690 extern void tcp_getconninfo(struct socket *, struct conninfo_tcp *);
1691 extern void add_to_time_wait(struct tcpcb *, uint32_t delay);
1692 extern void tcp_pmtud_revert_segment_size(struct tcpcb *tp);
1693 extern void tcp_rxtseg_insert(struct tcpcb *, tcp_seq, tcp_seq);
1694 extern struct tcp_rxt_seg *tcp_rxtseg_find(struct tcpcb *, tcp_seq, tcp_seq);
1695 extern void tcp_rxtseg_set_spurious(struct tcpcb *tp, tcp_seq start, tcp_seq end);
1696 extern void tcp_rxtseg_clean(struct tcpcb *);
1697 extern boolean_t tcp_rxtseg_detect_bad_rexmt(struct tcpcb *, tcp_seq);
1698 extern boolean_t tcp_rxtseg_dsack_for_tlp(struct tcpcb *);
1699 extern u_int32_t tcp_rxtseg_total_size(struct tcpcb *tp);
1700 extern void tcp_rexmt_save_state(struct tcpcb *tp);
1701 extern void tcp_interface_send_probe(u_int16_t if_index_available);
1702 extern void tcp_probe_connectivity(struct ifnet *ifp, u_int32_t enable);
1703 extern void tcp_get_connectivity_status(struct tcpcb *,
1704     struct tcp_conn_status *);
1705 
1706 extern void tcp_clear_keep_alive_offload(struct socket *so);
1707 extern void tcp_fill_keepalive_offload_frames(struct ifnet *,
1708     struct ifnet_keepalive_offload_frame *, u_int32_t, size_t, u_int32_t *);
1709 extern int tcp_notify_kao_timeout(ifnet_t ifp,
1710     struct ifnet_keepalive_offload_frame *frame);
1711 
1712 extern boolean_t tfo_enabled(const struct tcpcb *tp);
1713 extern void tcp_disable_tfo(struct tcpcb *tp);
1714 extern void tcp_tfo_gen_cookie(struct inpcb *inp, u_char *out, size_t blk_size);
1715 #define TCP_FASTOPEN_KEYLEN 16
1716 extern int tcp_freeq(struct tcpcb *tp);
1717 extern errno_t tcp_notify_ack_id_valid(struct tcpcb *, struct socket *, u_int32_t);
1718 extern errno_t tcp_add_notify_ack_marker(struct tcpcb *, u_int32_t);
1719 extern void tcp_notify_ack_free(struct tcpcb *);
1720 extern void tcp_notify_acknowledgement(struct tcpcb *, struct socket *);
1721 extern void tcp_get_notify_ack_count(struct tcpcb *,
1722     struct tcp_notify_ack_complete *);
1723 extern void tcp_get_notify_ack_ids(struct tcpcb *tp,
1724     struct tcp_notify_ack_complete *);
1725 extern void tcp_update_mss_locked(struct socket *, struct ifnet *);
1726 
1727 extern int get_tcp_inp_list(struct inpcb **, int, inp_gen_t);
1728 extern bool tcp_notify_ack_active(struct socket *so);
1729 extern void tcp_set_finwait_timeout(struct tcpcb *);
1730 
1731 #if MPTCP
1732 extern int mptcp_input_preproc(struct tcpcb *tp, struct mbuf *m,
1733     struct tcphdr *th, int drop_hdrlen);
1734 extern uint16_t mptcp_output_csum(struct mbuf *m, uint64_t dss_val,
1735     uint32_t sseq, uint16_t dlen);
1736 extern int mptcp_adj_mss(struct tcpcb *, boolean_t);
1737 extern void mptcp_insert_rmap(struct tcpcb *tp, struct mbuf *m, struct tcphdr *th);
1738 extern int dump_mptcp_reass_qlen(char *, int);
1739 #endif
1740 
1741 extern int dump_tcp_reass_qlen(char *, int);
1742 extern uint32_t tcp_reass_qlen_space(struct socket *);
1743 
1744 __private_extern__ void tcp_update_stats_per_flow(
1745 	struct ifnet_stats_per_flow *, struct ifnet *);
1746 
1747 #define TCP_ACK_STRATEGY_LEGACY 0
1748 #define TCP_ACK_STRATEGY_MODERN 1
1749 
1750 extern int tcp_ack_strategy;
1751 
1752 #if defined(SKYWALK)
1753 void tcp_add_fsw_flow(struct tcpcb *, struct ifnet *);
1754 void tcp_del_fsw_flow(struct tcpcb *);
1755 #else
1756 #define tcp_add_fsw_flow(...)
1757 #define tcp_del_fsw_flow(...)
1758 #endif
1759 
1760 #endif /* BSD_KERNEL_PRIVATE */
1761 
1762 #endif /* _NETINET_TCP_VAR_H_ */
1763