1 | /* |
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3 | * |
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27 | */ |
28 | /* |
29 | * Copyright (c) 1982, 1986, 1993 |
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_timer.h 8.1 (Berkeley) 6/10/93 |
61 | * $FreeBSD: src/sys/netinet/tcp_timer.h,v 1.18 1999/12/29 04:41:03 peter Exp $ |
62 | */ |
63 | |
64 | #ifndef _NETINET_TCP_TIMER_H_ |
65 | #define _NETINET_TCP_TIMER_H_ |
66 | #include <sys/appleapiopts.h> |
67 | |
68 | #ifdef BSD_KERNEL_PRIVATE |
69 | #include <kern/thread_call.h> |
70 | #endif /* BSD_KERNEL_PRIVATE */ |
71 | |
72 | /* Keep the external definition the same for binary compatibility */ |
73 | #define TCPT_NTIMERS_EXT 4 |
74 | |
75 | /* |
76 | * Definitions of the TCP timers. |
77 | * |
78 | * The TCPT_PTO timer is used for probing for a tail loss in a send window. |
79 | * If this probe gets acknowledged using SACK, it will allow the connection |
80 | * to enter fast-recovery instead of hitting a retransmit timeout. A probe |
81 | * timeout will send the last unacknowledged segment to generate more acks |
82 | * with SACK information which can be used for fast-retransmiting the lost |
83 | * packets. This will fire in the order of 10ms. |
84 | * |
85 | * The TCPT_REXMT timer is used to force retransmissions. |
86 | * The TCP has the TCPT_REXMT timer set whenever segments |
87 | * have been sent for which ACKs are expected but not yet |
88 | * received. If an ACK is received which advances tp->snd_una, |
89 | * then the retransmit timer is cleared (if there are no more |
90 | * outstanding segments) or reset to the base value (if there |
91 | * are more ACKs expected). Whenever the retransmit timer goes off, |
92 | * we retransmit one unacknowledged segment, and do a backoff |
93 | * on the retransmit timer. |
94 | * |
95 | * The TCPT_DELACK timer is used for transmitting delayed acknowledgements |
96 | * if an acknowledgement was delayed in anticipation of a new segment. |
97 | * |
98 | * The TCPT_PERSIST timer is used to keep window size information |
99 | * flowing even if the window goes shut. If all previous transmissions |
100 | * have been acknowledged(so that there are no retransmissions in progress), |
101 | * and the window is too small to bother sending anything, then we start |
102 | * the TCPT_PERSIST timer. When it expires, if the window is nonzero, |
103 | * we go to transmit state. Otherwise, at intervals send a single byte |
104 | * into the peer's window to force him to update our window information. |
105 | * We do this at most as often as TCPT_PERSMIN time intervals, |
106 | * but no more frequently than the current estimate of round-trip |
107 | * packet time. The TCPT_PERSIST timer is cleared whenever we receive |
108 | * a window update from the peer. |
109 | * |
110 | * The TCPT_KEEP timer is used to keep connections alive. If an |
111 | * connection is idle (no segments received) for TCPTV_KEEP_INIT amount |
112 | * of time, but not yet established, then we drop the connection. |
113 | * Once the connection is established, if the connection is idle for |
114 | * TCPTV_KEEP_IDLE time (and keepalives have been enabled on the socket), |
115 | * we begin to probe the connection. We force the peer to send us a |
116 | * segment by sending: |
117 | * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK> |
118 | * This segment is (deliberately) outside the window, and should elicit |
119 | * an ack segment in response from the peer. If, despite the TCPT_KEEP |
120 | * initiated segments we cannot elicit a response from a peer in |
121 | * TCPT_MAXIDLE amount of time probing, then we drop the connection. |
122 | * |
123 | * The TCPT_2MSL timer is used for keeping the conenction in Time-wait state |
124 | * before fully closing it so that the connection 4-tuple can be reused. |
125 | */ |
126 | #ifdef BSD_KERNEL_PRIVATE |
127 | |
128 | #define TCPT_PTO 0 /* Probe timeout */ |
129 | #define TCPT_DELAYFR 1 /* Delay recovery if there is reordering */ |
130 | #define TCPT_REXMT 2 /* retransmit */ |
131 | #define TCPT_DELACK 3 /* delayed ack */ |
132 | #define TCPT_PERSIST 4 /* retransmit persistence */ |
133 | #define TCPT_KEEP 5 /* keep alive */ |
134 | #define TCPT_2MSL 6 /* 2*msl quiet time timer */ |
135 | #if MPTCP |
136 | #define TCPT_JACK_RXMT 7 /* retransmit timer for join ack */ |
137 | #define TCPT_CELLICON 8 /* Timer to check for cell-activity */ |
138 | #define TCPT_MAX 8 |
139 | #else /* MPTCP */ |
140 | #define TCPT_MAX 6 |
141 | #endif /* !MPTCP */ |
142 | |
143 | #define TCPT_NONE (TCPT_MAX + 1) |
144 | #define TCPT_NTIMERS (TCPT_MAX + 1) |
145 | |
146 | /* External definitions */ |
147 | #define TCPT_REXMT_EXT 0 |
148 | #define TCPT_PERSIST_EXT 1 |
149 | #define TCPT_KEEP_EXT 2 |
150 | #define TCPT_2MSL_EXT 3 |
151 | #define TCPT_DELACK_EXT 4 |
152 | |
153 | #else /* !BSD_KERNEL_PRIVATE */ |
154 | #define TCPT_REXMT 0 /* retransmit */ |
155 | #define TCPT_PERSIST 1 /* retransmit persistence */ |
156 | #define TCPT_KEEP 2 /* keep alive */ |
157 | #define TCPT_2MSL 3 /* 2*msl quiet time timer */ |
158 | #define TCPT_DELACK 4 /* delayed ack timer */ |
159 | #if MPTCP |
160 | #define TCPT_JACK_RXMT 5 /* retransmit timer for join ack */ |
161 | #define TCPT_MAX 5 |
162 | #else /* MPTCP */ |
163 | #define TCPT_MAX 4 |
164 | #endif /* !MPTCP */ |
165 | #define TCPT_NONE (TCPT_MAX + 1) |
166 | #define TCPT_NTIMERS (TCPT_MAX + 1) |
167 | |
168 | #endif /* BSD_KERNEL_PRIVATE */ |
169 | |
170 | #ifdef BSD_KERNEL_PRIVATE |
171 | /* |
172 | * Time constants. |
173 | */ |
174 | #define TCPTV_MSL ( 15*TCP_RETRANSHZ) /* max seg lifetime */ |
175 | #define TCPTV_SRTTBASE 0 /* base roundtrip time; if 0, no idea yet */ |
176 | #define TCPTV_RTOBASE ( 1*TCP_RETRANSHZ) /* assumed RTO if no info */ |
177 | #define TCPTV_SRTTDFLT ( 1*TCP_RETRANSHZ) /* assumed RTT if no info */ |
178 | #define TCPTV_PERSMIN ( 5*TCP_RETRANSHZ) /* retransmit persistence */ |
179 | #define TCPTV_PERSMAX ( 60*TCP_RETRANSHZ) /* maximum persist interval */ |
180 | |
181 | extern int tcptv_persmin_val; |
182 | |
183 | #define TCPTV_KEEP_INIT ( 75*TCP_RETRANSHZ) /* connect keep alive */ |
184 | #define TCPTV_KEEP_IDLE (120*60*TCP_RETRANSHZ) /* time before probing */ |
185 | #define TCPTV_KEEPINTVL ( 75*TCP_RETRANSHZ) /* default probe interval */ |
186 | #define TCPTV_KEEPCNT 8 /* max probes before drop */ |
187 | |
188 | #define TCPTV_REXMTMAX ( 64*TCP_RETRANSHZ ) /* max REXMT value */ |
189 | #define TCPTV_REXMTMIN ( TCP_RETRANSHZ/33 ) /* min REXMT for non-local connections */ |
190 | |
191 | #define TCPTV_FINWAIT2 ( 60*TCP_RETRANSHZ) /* timeout to get out of FIN_WAIT_2 */ |
192 | |
193 | /* |
194 | * Window for counting received bytes to see if ack-stretching |
195 | * can start (default 100 ms) |
196 | */ |
197 | #define TCPTV_UNACKWIN ( TCP_RETRANSHZ/10 ) |
198 | |
199 | /* Receiver idle time, avoid ack-stretching after this idle time */ |
200 | #define TCPTV_MAXRCVIDLE (TCP_RETRANSHZ/5 ) |
201 | |
202 | /* |
203 | * No ack stretching during slow-start, until we see some packets. |
204 | * By the time the receiver gets 512 packets, the senders cwnd |
205 | * should open by a few hundred packets consdering the |
206 | * slow-start progression. |
207 | */ |
208 | #define TCP_RCV_SS_PKTCOUNT 512 |
209 | |
210 | #define TCPTV_TWTRUNC 8 /* RTO factor to truncate TW */ |
211 | |
212 | #define TCP_LINGERTIME 120 /* linger at most 2 minutes */ |
213 | |
214 | #define TCP_MAXRXTSHIFT 12 /* maximum retransmits */ |
215 | |
216 | #ifdef TCPTIMERS |
217 | static char *tcptimers[] = |
218 | { "REXMT" , "PERSIST" , "KEEP" , "2MSL" , "DELACK" }; |
219 | #endif /* TCPTIMERS */ |
220 | |
221 | /* |
222 | * Persist, keep, 2msl and MPTCP's join-ack timer as slow timers which can |
223 | * be coalesced at a higher granularity (500 ms). |
224 | * |
225 | * Rexmt and delayed ack timers are considered as fast timers which run |
226 | * in the order of 100ms. |
227 | * |
228 | * Probe timeout is a quick timer which will run in the order of 10ms. |
229 | */ |
230 | #define IS_TIMER_HZ_500MS(i) ((i) >= TCPT_PERSIST) |
231 | #define IS_TIMER_HZ_100MS(i) ((i) >= TCPT_REXMT && (i) < TCPT_PERSIST) |
232 | #define IS_TIMER_HZ_10MS(i) ((i) < TCPT_REXMT) |
233 | |
234 | struct tcptimerlist; |
235 | |
236 | struct tcptimerentry { |
237 | LIST_ENTRY(tcptimerentry) le; /* links for timer list */ |
238 | uint32_t timer_start; /* tcp clock when the timer was started */ |
239 | uint16_t index; /* index of lowest timer that needs to run first */ |
240 | uint16_t mode; /* Bit-wise OR of timers that are active */ |
241 | uint32_t runtime; /* deadline at which the first timer has to fire */ |
242 | }; |
243 | |
244 | LIST_HEAD(timerlisthead, tcptimerentry); |
245 | |
246 | struct tcptimerlist { |
247 | struct timerlisthead lhead; /* head of the list */ |
248 | lck_mtx_t mtx; /* lock to protect the list */ |
249 | lck_grp_t *mtx_grp; /* mutex group definition */ |
250 | thread_call_t call; /* call entry */ |
251 | uint32_t runtime; /* time at which this list is going to run */ |
252 | uint32_t schedtime; /* time at which this list was scheduled */ |
253 | uint32_t entries; /* Number of entries on the list */ |
254 | uint32_t maxentries; /* Max number of entries at any time */ |
255 | |
256 | /* Set desired mode when timer list running */ |
257 | boolean_t running; /* Set when timer list is being processed */ |
258 | boolean_t scheduled; /* set when the timer is scheduled */ |
259 | #define TCP_TIMERLIST_10MS_MODE 0x1 |
260 | #define TCP_TIMERLIST_100MS_MODE 0x2 |
261 | #define TCP_TIMERLIST_500MS_MODE 0x4 |
262 | uint32_t mode; /* Current mode of the timer */ |
263 | uint32_t pref_mode; /* Preferred mode set by a connection */ |
264 | uint32_t pref_offset; /* Preferred offset set by a connection */ |
265 | uint32_t idleruns; /* Number of times the list has been idle in fast mode */ |
266 | struct tcptimerentry *next_te; /* next timer entry pointer to process */ |
267 | u_int16_t probe_if_index; /* Interface index that needs to send probes */ |
268 | }; |
269 | |
270 | /* number of idle runs allowed for TCP timer list in fast or quick modes */ |
271 | #define TCP_FASTMODE_IDLERUN_MAX 10 |
272 | |
273 | /* |
274 | * Minimum retransmit timeout is set to 30ms. We add a slop of |
275 | * 200 ms to the retransmit value to account for processing |
276 | * variance and delayed ack. This extra 200ms will help to avoid |
277 | * spurious retransmits by taking into consideration the receivers |
278 | * that wait for delayed ack timer instead of generating an ack |
279 | * for every two packets. |
280 | * |
281 | * On a local link, the minimum retransmit timeout is 100ms and |
282 | * variance is set to 0. This will make the sender a little bit more |
283 | * aggressive on local link. When the connection is not established yet, |
284 | * there is no need to add an extra 200ms to retransmit timeout because |
285 | * the initial value is high (1s) and delayed ack is not a problem in |
286 | * that case. |
287 | */ |
288 | #define TCPTV_REXMTSLOP ( TCP_RETRANSHZ/5 ) /* extra 200 ms slop */ |
289 | |
290 | /* macro to decide when retransmit slop (described above) should be added */ |
291 | #define TCP_ADD_REXMTSLOP(tp) (tp->t_state >= TCPS_ESTABLISHED) |
292 | |
293 | #define TCPT_RANGESET(tv, value, tvmin, tvmax, addslop) do { \ |
294 | (tv) = ((addslop) ? tcp_rexmt_slop : 0) + (value); \ |
295 | if ((uint32_t)(tv) < (uint32_t)(tvmin)) \ |
296 | (tv) = (tvmin); \ |
297 | else if ((uint32_t)(tv) > (uint32_t)(tvmax)) \ |
298 | (tv) = (tvmax); \ |
299 | } while(0) |
300 | |
301 | #define TCP_CONN_KEEPIDLE(tp) \ |
302 | ((tp)->t_keepidle && \ |
303 | ((tp)->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) ? \ |
304 | (tp)->t_keepidle : (uint32_t)tcp_keepidle) |
305 | #define TCP_CONN_KEEPINIT(tp) \ |
306 | (((tp)->t_keepinit > 0) ? (tp)->t_keepinit : (uint32_t)tcp_keepinit) |
307 | #define TCP_CONN_KEEPCNT(tp) \ |
308 | (((tp)->t_keepcnt > 0) ? (tp)->t_keepcnt : (uint32_t)tcp_keepcnt) |
309 | #define TCP_CONN_KEEPINTVL(tp) \ |
310 | (((tp)->t_keepintvl > 0) ? (tp)->t_keepintvl : (uint32_t)tcp_keepintvl) |
311 | #define TCP_CONN_MAXIDLE(tp) \ |
312 | (TCP_CONN_KEEPCNT(tp) * TCP_CONN_KEEPINTVL(tp)) |
313 | |
314 | #define TCP_IDLETIMEOUT(tp) \ |
315 | (((TCP_ADD_REXMTSLOP(tp)) ? 0 : tcp_rexmt_slop) + tp->t_rxtcur) |
316 | |
317 | TAILQ_HEAD(tcptailq, tcpcb); |
318 | |
319 | extern int tcp_keepinit; /* time to establish connection */ |
320 | extern int tcp_keepidle; /* time before keepalive probes begin */ |
321 | extern int tcp_keepintvl; /* time between keepalive probes */ |
322 | extern int tcp_keepcnt; /* number of keepalives */ |
323 | extern int tcp_delack; /* delayed ack timer */ |
324 | extern int tcp_maxpersistidle; |
325 | extern int tcp_msl; |
326 | extern int tcp_ttl; /* time to live for TCP segs */ |
327 | extern int tcp_backoff[]; |
328 | extern int tcp_rexmt_slop; |
329 | extern u_int32_t tcp_max_persist_timeout; /* Maximum persistence for Zero Window Probes */ |
330 | |
331 | #define OFFSET_FROM_START(tp, off) ((tcp_now + (off)) - (tp)->tentry.timer_start) |
332 | |
333 | #endif /* BSD_KERNEL_PRIVATE */ |
334 | #endif /* !_NETINET_TCP_TIMER_H_ */ |
335 | |