FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_var.h
1 /*
2 * Copyright (c) 1982, 1986, 1993, 1994, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)tcp_var.h 8.4 (Berkeley) 5/24/95
34 * $FreeBSD$
35 */
36
37 #ifndef _NETINET_TCP_VAR_H_
38 #define _NETINET_TCP_VAR_H_
39 /*
40 * Kernel variables for tcp.
41 */
42
43 /*
44 * Tcp control block, one per tcp; fields:
45 * Organized for 16 byte cacheline efficiency.
46 */
47 struct tcpcb {
48 struct mbuf *t_segq;
49 int t_dupacks; /* consecutive dup acks recd */
50 struct tcpiphdr *t_template; /* skeletal packet for transmit */
51
52 int t_timer[TCPT_NTIMERS]; /* tcp timers */
53
54 struct inpcb *t_inpcb; /* back pointer to internet pcb */
55 int t_state; /* state of this connection */
56 u_int t_flags;
57 #define TF_ACKNOW 0x00001 /* ack peer immediately */
58 #define TF_DELACK 0x00002 /* ack, but try to delay it */
59 #define TF_NODELAY 0x00004 /* don't delay packets to coalesce */
60 #define TF_NOOPT 0x00008 /* don't use tcp options */
61 #define TF_SENTFIN 0x00010 /* have sent FIN */
62 #define TF_REQ_SCALE 0x00020 /* have/will request window scaling */
63 #define TF_RCVD_SCALE 0x00040 /* other side has requested scaling */
64 #define TF_REQ_TSTMP 0x00080 /* have/will request timestamps */
65 #define TF_RCVD_TSTMP 0x00100 /* a timestamp was received in SYN */
66 #define TF_SACK_PERMIT 0x00200 /* other side said I could SACK */
67 #define TF_NEEDSYN 0x00400 /* send SYN (implicit state) */
68 #define TF_NEEDFIN 0x00800 /* send FIN (implicit state) */
69 #define TF_NOPUSH 0x01000 /* don't push */
70 #define TF_REQ_CC 0x02000 /* have/will request CC */
71 #define TF_RCVD_CC 0x04000 /* a CC was received in SYN */
72 #define TF_SENDCCNEW 0x08000 /* send CCnew instead of CC in SYN */
73 #define TF_MORETOCOME 0x10000 /* More data to be appended to sock */
74 int t_force; /* 1 if forcing out a byte */
75
76 tcp_seq snd_una; /* send unacknowledged */
77 tcp_seq snd_max; /* highest sequence number sent;
78 * used to recognize retransmits
79 */
80 tcp_seq snd_nxt; /* send next */
81 tcp_seq snd_up; /* send urgent pointer */
82
83 tcp_seq snd_wl1; /* window update seg seq number */
84 tcp_seq snd_wl2; /* window update seg ack number */
85 tcp_seq iss; /* initial send sequence number */
86 tcp_seq irs; /* initial receive sequence number */
87
88 tcp_seq rcv_nxt; /* receive next */
89 tcp_seq rcv_adv; /* advertised window */
90 u_long rcv_wnd; /* receive window */
91 tcp_seq rcv_up; /* receive urgent pointer */
92
93 u_long snd_wnd; /* send window */
94 u_long snd_cwnd; /* congestion-controlled window */
95 u_long snd_ssthresh; /* snd_cwnd size threshold for
96 * for slow start exponential to
97 * linear switch
98 */
99 u_int t_maxopd; /* mss plus options */
100
101 u_int t_idle; /* inactivity time */
102 u_long t_duration; /* connection duration */
103 int t_rtt; /* round trip time */
104 tcp_seq t_rtseq; /* sequence number being timed */
105
106 int t_rxtcur; /* current retransmit value */
107 u_int t_maxseg; /* maximum segment size */
108 int t_srtt; /* smoothed round-trip time */
109 int t_rttvar; /* variance in round-trip time */
110
111 int t_rxtshift; /* log(2) of rexmt exp. backoff */
112 u_int t_rttmin; /* minimum rtt allowed */
113 u_long t_rttupdated; /* number of times rtt sampled */
114 u_long max_sndwnd; /* largest window peer has offered */
115
116 int t_softerror; /* possible error not yet reported */
117 /* out-of-band data */
118 char t_oobflags; /* have some */
119 char t_iobc; /* input character */
120 #define TCPOOB_HAVEDATA 0x01
121 #define TCPOOB_HADDATA 0x02
122 /* RFC 1323 variables */
123 u_char snd_scale; /* window scaling for send window */
124 u_char rcv_scale; /* window scaling for recv window */
125 u_char request_r_scale; /* pending window scaling */
126 u_char requested_s_scale;
127 u_long ts_recent; /* timestamp echo data */
128
129 u_long ts_recent_age; /* when last updated */
130 tcp_seq last_ack_sent;
131 /* RFC 1644 variables */
132 tcp_cc cc_send; /* send connection count */
133 tcp_cc cc_recv; /* receive connection count */
134 };
135
136 /*
137 * Structure to hold TCP options that are only used during segment
138 * processing (in tcp_input), but not held in the tcpcb.
139 * It's basically used to reduce the number of parameters
140 * to tcp_dooptions.
141 */
142 struct tcpopt {
143 u_long to_flag; /* which options are present */
144 #define TOF_TS 0x0001 /* timestamp */
145 #define TOF_CC 0x0002 /* CC and CCnew are exclusive */
146 #define TOF_CCNEW 0x0004
147 #define TOF_CCECHO 0x0008
148 u_long to_tsval;
149 u_long to_tsecr;
150 tcp_cc to_cc; /* holds CC or CCnew */
151 tcp_cc to_ccecho;
152 };
153
154 /*
155 * The TAO cache entry which is stored in the protocol family specific
156 * portion of the route metrics.
157 */
158 struct rmxp_tao {
159 tcp_cc tao_cc; /* latest CC in valid SYN */
160 tcp_cc tao_ccsent; /* latest CC sent to peer */
161 u_short tao_mssopt; /* peer's cached MSS */
162 #ifdef notyet
163 u_short tao_flags; /* cache status flags */
164 #define TAOF_DONT 0x0001 /* peer doesn't understand rfc1644 */
165 #define TAOF_OK 0x0002 /* peer does understand rfc1644 */
166 #define TAOF_UNDEF 0 /* we don't know yet */
167 #endif /* notyet */
168 };
169 #define rmx_taop(r) ((struct rmxp_tao *)(r).rmx_filler)
170
171 #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
172 #define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
173
174 /*
175 * The smoothed round-trip time and estimated variance
176 * are stored as fixed point numbers scaled by the values below.
177 * For convenience, these scales are also used in smoothing the average
178 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
179 * With these scales, srtt has 3 bits to the right of the binary point,
180 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
181 * binary point, and is smoothed with an ALPHA of 0.75.
182 */
183 #define TCP_RTT_SCALE 32 /* multiplier for srtt; 3 bits frac. */
184 #define TCP_RTT_SHIFT 5 /* shift for srtt; 3 bits frac. */
185 #define TCP_RTTVAR_SCALE 16 /* multiplier for rttvar; 2 bits */
186 #define TCP_RTTVAR_SHIFT 4 /* shift for rttvar; 2 bits */
187 #define TCP_DELTA_SHIFT 2 /* see tcp_input.c */
188
189 /*
190 * The initial retransmission should happen at rtt + 4 * rttvar.
191 * Because of the way we do the smoothing, srtt and rttvar
192 * will each average +1/2 tick of bias. When we compute
193 * the retransmit timer, we want 1/2 tick of rounding and
194 * 1 extra tick because of +-1/2 tick uncertainty in the
195 * firing of the timer. The bias will give us exactly the
196 * 1.5 tick we need. But, because the bias is
197 * statistical, we have to test that we don't drop below
198 * the minimum feasible timer (which is 2 ticks).
199 * This version of the macro adapted from a paper by Lawrence
200 * Brakmo and Larry Peterson which outlines a problem caused
201 * by insufficient precision in the original implementation,
202 * which results in inappropriately large RTO values for very
203 * fast networks.
204 */
205 #define TCP_REXMTVAL(tp) \
206 max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT)) \
207 + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
208
209 /*
210 * TCP statistics.
211 * Many of these should be kept per connection,
212 * but that's inconvenient at the moment.
213 */
214 struct tcpstat {
215 u_long tcps_connattempt; /* connections initiated */
216 u_long tcps_accepts; /* connections accepted */
217 u_long tcps_connects; /* connections established */
218 u_long tcps_drops; /* connections dropped */
219 u_long tcps_conndrops; /* embryonic connections dropped */
220 u_long tcps_closed; /* conn. closed (includes drops) */
221 u_long tcps_segstimed; /* segs where we tried to get rtt */
222 u_long tcps_rttupdated; /* times we succeeded */
223 u_long tcps_delack; /* delayed acks sent */
224 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
225 u_long tcps_rexmttimeo; /* retransmit timeouts */
226 u_long tcps_persisttimeo; /* persist timeouts */
227 u_long tcps_keeptimeo; /* keepalive timeouts */
228 u_long tcps_keepprobe; /* keepalive probes sent */
229 u_long tcps_keepdrops; /* connections dropped in keepalive */
230
231 u_long tcps_sndtotal; /* total packets sent */
232 u_long tcps_sndpack; /* data packets sent */
233 u_long tcps_sndbyte; /* data bytes sent */
234 u_long tcps_sndrexmitpack; /* data packets retransmitted */
235 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
236 u_long tcps_sndacks; /* ack-only packets sent */
237 u_long tcps_sndprobe; /* window probes sent */
238 u_long tcps_sndurg; /* packets sent with URG only */
239 u_long tcps_sndwinup; /* window update-only packets sent */
240 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
241
242 u_long tcps_rcvtotal; /* total packets received */
243 u_long tcps_rcvpack; /* packets received in sequence */
244 u_long tcps_rcvbyte; /* bytes received in sequence */
245 u_long tcps_rcvbadsum; /* packets received with ccksum errs */
246 u_long tcps_rcvbadoff; /* packets received with bad offset */
247 u_long tcps_rcvshort; /* packets received too short */
248 u_long tcps_rcvduppack; /* duplicate-only packets received */
249 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
250 u_long tcps_rcvpartduppack; /* packets with some duplicate data */
251 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
252 u_long tcps_rcvoopack; /* out-of-order packets received */
253 u_long tcps_rcvoobyte; /* out-of-order bytes received */
254 u_long tcps_rcvpackafterwin; /* packets with data after window */
255 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
256 u_long tcps_rcvafterclose; /* packets rcvd after "close" */
257 u_long tcps_rcvwinprobe; /* rcvd window probe packets */
258 u_long tcps_rcvdupack; /* rcvd duplicate acks */
259 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
260 u_long tcps_rcvackpack; /* rcvd ack packets */
261 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
262 u_long tcps_rcvwinupd; /* rcvd window update packets */
263 u_long tcps_pawsdrop; /* segments dropped due to PAWS */
264 u_long tcps_predack; /* times hdr predict ok for acks */
265 u_long tcps_preddat; /* times hdr predict ok for data pkts */
266 u_long tcps_pcbcachemiss;
267 u_long tcps_cachedrtt; /* times cached RTT in route updated */
268 u_long tcps_cachedrttvar; /* times cached rttvar updated */
269 u_long tcps_cachedssthresh; /* times cached ssthresh updated */
270 u_long tcps_usedrtt; /* times RTT initialized from route */
271 u_long tcps_usedrttvar; /* times RTTVAR initialized from rt */
272 u_long tcps_usedssthresh; /* times ssthresh initialized from rt*/
273 u_long tcps_persistdrop; /* timeout in persist state */
274 u_long tcps_badsyn; /* bogus SYN, e.g. premature ACK */
275 u_long tcps_mturesent; /* resends due to MTU discovery */
276 u_long tcps_listendrop; /* listen queue overflows */
277 };
278
279 /*
280 * TCB structure exported to user-land via sysctl(3).
281 * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
282 * included. Not all of our clients do.
283 */
284 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
285 struct xtcpcb {
286 size_t xt_len;
287 struct inpcb xt_inp;
288 struct tcpcb xt_tp;
289 struct xsocket xt_socket;
290 u_quad_t xt_alignment_hack;
291 };
292 #endif
293
294 /*
295 * Names for TCP sysctl objects
296 */
297 #define TCPCTL_DO_RFC1323 1 /* use RFC-1323 extensions */
298 #define TCPCTL_DO_RFC1644 2 /* use RFC-1644 extensions */
299 #define TCPCTL_MSSDFLT 3 /* MSS default */
300 #define TCPCTL_STATS 4 /* statistics (read-only) */
301 #define TCPCTL_RTTDFLT 5 /* default RTT estimate */
302 #define TCPCTL_KEEPIDLE 6 /* keepalive idle timer */
303 #define TCPCTL_KEEPINTVL 7 /* interval to send keepalives */
304 #define TCPCTL_SENDSPACE 8 /* send buffer space */
305 #define TCPCTL_RECVSPACE 9 /* receive buffer space */
306 #define TCPCTL_KEEPINIT 10 /* timeout for establishing syn */
307 #define TCPCTL_PCBLIST 11 /* list of all outstanding PCBs */
308 #define TCPCTL_MAXID 12
309
310 #define TCPCTL_NAMES { \
311 { 0, 0 }, \
312 { "rfc1323", CTLTYPE_INT }, \
313 { "rfc1644", CTLTYPE_INT }, \
314 { "mssdflt", CTLTYPE_INT }, \
315 { "stats", CTLTYPE_STRUCT }, \
316 { "rttdflt", CTLTYPE_INT }, \
317 { "keepidle", CTLTYPE_INT }, \
318 { "keepintvl", CTLTYPE_INT }, \
319 { "sendspace", CTLTYPE_INT }, \
320 { "recvspace", CTLTYPE_INT }, \
321 { "keepinit", CTLTYPE_INT }, \
322 { "pcblist", CTLTYPE_STRUCT }, \
323 }
324
325 #ifdef KERNEL
326 extern struct inpcbhead tcb; /* head of queue of active tcpcb's */
327 extern struct inpcbinfo tcbinfo;
328 extern struct tcpstat tcpstat; /* tcp statistics */
329 extern int tcp_mssdflt; /* XXX */
330 extern u_long tcp_now; /* for RFC 1323 timestamps */
331 extern int tcp_delack_enabled;
332
333 void tcp_canceltimers __P((struct tcpcb *));
334 struct tcpcb *
335 tcp_close __P((struct tcpcb *));
336 void tcp_ctlinput __P((int, struct sockaddr *, void *));
337 int tcp_ctloutput __P((struct socket *, struct sockopt *));
338 struct tcpcb *
339 tcp_drop __P((struct tcpcb *, int));
340 void tcp_drain __P((void));
341 void tcp_fasttimo __P((void));
342 struct rmxp_tao *
343 tcp_gettaocache __P((struct inpcb *));
344 void tcp_init __P((void));
345 void tcp_input __P((struct mbuf *, int));
346 void tcp_mss __P((struct tcpcb *, int));
347 int tcp_mssopt __P((struct tcpcb *));
348 void tcp_mtudisc __P((struct inpcb *, int));
349 struct tcpcb *
350 tcp_newtcpcb __P((struct inpcb *));
351 int tcp_output __P((struct tcpcb *));
352 void tcp_quench __P((struct inpcb *, int));
353 void tcp_respond __P((struct tcpcb *,
354 struct tcpiphdr *, struct mbuf *, tcp_seq, tcp_seq, int));
355 struct rtentry *
356 tcp_rtlookup __P((struct inpcb *));
357 void tcp_setpersist __P((struct tcpcb *));
358 void tcp_slowtimo __P((void));
359 struct tcpiphdr *
360 tcp_template __P((struct tcpcb *));
361 struct tcpcb *
362 tcp_timers __P((struct tcpcb *, int));
363 void tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int));
364
365 extern struct pr_usrreqs tcp_usrreqs;
366 extern u_long tcp_sendspace;
367 extern u_long tcp_recvspace;
368 void tcp_rndiss_init __P((void));
369 tcp_seq tcp_rndiss_next __P((void));
370 u_int16_t
371 tcp_rndiss_encrypt __P((u_int16_t));
372
373 #endif /* KERNEL */
374
375 #endif /* _NETINET_TCP_VAR_H_ */
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