source: rtems/c/src/libnetworking/netinet/tcp_var.h @ 39e6e65a

4.104.114.84.95
Last change on this file since 39e6e65a was 39e6e65a, checked in by Joel Sherrill <joel.sherrill@…>, on 08/19/98 at 21:32:28

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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 *      $Id$
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 */
46struct tcpcb {
47        struct  tcpiphdr *seg_next;     /* sequencing queue */
48        struct  tcpiphdr *seg_prev;
49        int     t_state;                /* state of this connection */
50        int     t_timer[TCPT_NTIMERS];  /* tcp timers */
51        int     t_rxtshift;             /* log(2) of rexmt exp. backoff */
52        int     t_rxtcur;               /* current retransmit value */
53        int     t_dupacks;              /* consecutive dup acks recd */
54        u_int   t_maxseg;               /* maximum segment size */
55        u_int   t_maxopd;               /* mss plus options */
56        int     t_force;                /* 1 if forcing out a byte */
57        u_int   t_flags;
58#define TF_ACKNOW       0x0001          /* ack peer immediately */
59#define TF_DELACK       0x0002          /* ack, but try to delay it */
60#define TF_NODELAY      0x0004          /* don't delay packets to coalesce */
61#define TF_NOOPT        0x0008          /* don't use tcp options */
62#define TF_SENTFIN      0x0010          /* have sent FIN */
63#define TF_REQ_SCALE    0x0020          /* have/will request window scaling */
64#define TF_RCVD_SCALE   0x0040          /* other side has requested scaling */
65#define TF_REQ_TSTMP    0x0080          /* have/will request timestamps */
66#define TF_RCVD_TSTMP   0x0100          /* a timestamp was received in SYN */
67#define TF_SACK_PERMIT  0x0200          /* other side said I could SACK */
68#define TF_NEEDSYN      0x0400          /* send SYN (implicit state) */
69#define TF_NEEDFIN      0x0800          /* send FIN (implicit state) */
70#define TF_NOPUSH       0x1000          /* don't push */
71#define TF_REQ_CC       0x2000          /* have/will request CC */
72#define TF_RCVD_CC      0x4000          /* a CC was received in SYN */
73#define TF_SENDCCNEW    0x8000          /* send CCnew instead of CC in SYN */
74
75        struct  tcpiphdr *t_template;   /* skeletal packet for transmit */
76        struct  inpcb *t_inpcb;         /* back pointer to internet pcb */
77/*
78 * The following fields are used as in the protocol specification.
79 * See RFC783, Dec. 1981, page 21.
80 */
81/* send sequence variables */
82        tcp_seq snd_una;                /* send unacknowledged */
83        tcp_seq snd_nxt;                /* send next */
84        tcp_seq snd_up;                 /* send urgent pointer */
85        tcp_seq snd_wl1;                /* window update seg seq number */
86        tcp_seq snd_wl2;                /* window update seg ack number */
87        tcp_seq iss;                    /* initial send sequence number */
88        u_long  snd_wnd;                /* send window */
89/* receive sequence variables */
90        u_long  rcv_wnd;                /* receive window */
91        tcp_seq rcv_nxt;                /* receive next */
92        tcp_seq rcv_up;                 /* receive urgent pointer */
93        tcp_seq irs;                    /* initial receive sequence number */
94/*
95 * Additional variables for this implementation.
96 */
97/* receive variables */
98        tcp_seq rcv_adv;                /* advertised window */
99/* retransmit variables */
100        tcp_seq snd_max;                /* highest sequence number sent;
101                                         * used to recognize retransmits
102                                         */
103/* congestion control (for slow start, source quench, retransmit after loss) */
104        u_long  snd_cwnd;               /* congestion-controlled window */
105        u_long  snd_ssthresh;           /* snd_cwnd size threshold for
106                                         * for slow start exponential to
107                                         * linear switch
108                                         */
109/*
110 * transmit timing stuff.  See below for scale of srtt and rttvar.
111 * "Variance" is actually smoothed difference.
112 */
113        u_int   t_idle;                 /* inactivity time */
114        int     t_rtt;                  /* round trip time */
115        tcp_seq t_rtseq;                /* sequence number being timed */
116        int     t_srtt;                 /* smoothed round-trip time */
117        int     t_rttvar;               /* variance in round-trip time */
118        u_int   t_rttmin;               /* minimum rtt allowed */
119        u_long  max_sndwnd;             /* largest window peer has offered */
120
121/* out-of-band data */
122        char    t_oobflags;             /* have some */
123        char    t_iobc;                 /* input character */
124#define TCPOOB_HAVEDATA 0x01
125#define TCPOOB_HADDATA  0x02
126        int     t_softerror;            /* possible error not yet reported */
127
128/* RFC 1323 variables */
129        u_char  snd_scale;              /* window scaling for send window */
130        u_char  rcv_scale;              /* window scaling for recv window */
131        u_char  request_r_scale;        /* pending window scaling */
132        u_char  requested_s_scale;
133        u_long  ts_recent;              /* timestamp echo data */
134        u_long  ts_recent_age;          /* when last updated */
135        tcp_seq last_ack_sent;
136/* RFC 1644 variables */
137        tcp_cc  cc_send;                /* send connection count */
138        tcp_cc  cc_recv;                /* receive connection count */
139        u_long  t_duration;             /* connection duration */
140
141/* TUBA stuff */
142        caddr_t t_tuba_pcb;             /* next level down pcb for TCP over z */
143/* More RTT stuff */
144        u_long  t_rttupdated;           /* number of times rtt sampled */
145};
146
147/*
148 * Structure to hold TCP options that are only used during segment
149 * processing (in tcp_input), but not held in the tcpcb.
150 * It's basically used to reduce the number of parameters
151 * to tcp_dooptions.
152 */
153struct tcpopt {
154        u_long  to_flag;                /* which options are present */
155#define TOF_TS          0x0001          /* timestamp */
156#define TOF_CC          0x0002          /* CC and CCnew are exclusive */
157#define TOF_CCNEW       0x0004
158#define TOF_CCECHO      0x0008
159        u_long  to_tsval;
160        u_long  to_tsecr;
161        tcp_cc  to_cc;          /* holds CC or CCnew */
162        tcp_cc  to_ccecho;
163};
164
165/*
166 * The TAO cache entry which is stored in the protocol family specific
167 * portion of the route metrics.
168 */
169struct rmxp_tao {
170        tcp_cc  tao_cc;                 /* latest CC in valid SYN */
171        tcp_cc  tao_ccsent;             /* latest CC sent to peer */
172        u_short tao_mssopt;             /* peer's cached MSS */
173#ifdef notyet
174        u_short tao_flags;              /* cache status flags */
175#define TAOF_DONT       0x0001          /* peer doesn't understand rfc1644 */
176#define TAOF_OK         0x0002          /* peer does understand rfc1644 */
177#define TAOF_UNDEF      0               /* we don't know yet */
178#endif /* notyet */
179};
180#define rmx_taop(r)     ((struct rmxp_tao *)(r).rmx_filler)
181
182#define intotcpcb(ip)   ((struct tcpcb *)(ip)->inp_ppcb)
183#define sototcpcb(so)   (intotcpcb(sotoinpcb(so)))
184
185/*
186 * The smoothed round-trip time and estimated variance
187 * are stored as fixed point numbers scaled by the values below.
188 * For convenience, these scales are also used in smoothing the average
189 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
190 * With these scales, srtt has 3 bits to the right of the binary point,
191 * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
192 * binary point, and is smoothed with an ALPHA of 0.75.
193 */
194#define TCP_RTT_SCALE           32      /* multiplier for srtt; 3 bits frac. */
195#define TCP_RTT_SHIFT           5       /* shift for srtt; 3 bits frac. */
196#define TCP_RTTVAR_SCALE        16      /* multiplier for rttvar; 2 bits */
197#define TCP_RTTVAR_SHIFT        4       /* shift for rttvar; 2 bits */
198#define TCP_DELTA_SHIFT         2       /* see tcp_input.c */
199
200/*
201 * The initial retransmission should happen at rtt + 4 * rttvar.
202 * Because of the way we do the smoothing, srtt and rttvar
203 * will each average +1/2 tick of bias.  When we compute
204 * the retransmit timer, we want 1/2 tick of rounding and
205 * 1 extra tick because of +-1/2 tick uncertainty in the
206 * firing of the timer.  The bias will give us exactly the
207 * 1.5 tick we need.  But, because the bias is
208 * statistical, we have to test that we don't drop below
209 * the minimum feasible timer (which is 2 ticks).
210 * This version of the macro adapted from a paper by Lawrence
211 * Brakmo and Larry Peterson which outlines a problem caused
212 * by insufficient precision in the original implementation,
213 * which results in inappropriately large RTO values for very
214 * fast networks.
215 */
216#define TCP_REXMTVAL(tp) \
217        ((((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT))  \
218          + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
219
220/* XXX
221 * We want to avoid doing m_pullup on incoming packets but that
222 * means avoiding dtom on the tcp reassembly code.  That in turn means
223 * keeping an mbuf pointer in the reassembly queue (since we might
224 * have a cluster).  As a quick hack, the source & destination
225 * port numbers (which are no longer needed once we've located the
226 * tcpcb) are overlayed with an mbuf pointer.
227 */
228#define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t))
229
230/*
231 * TCP statistics.
232 * Many of these should be kept per connection,
233 * but that's inconvenient at the moment.
234 */
235struct  tcpstat {
236        u_long  tcps_connattempt;       /* connections initiated */
237        u_long  tcps_accepts;           /* connections accepted */
238        u_long  tcps_connects;          /* connections established */
239        u_long  tcps_drops;             /* connections dropped */
240        u_long  tcps_conndrops;         /* embryonic connections dropped */
241        u_long  tcps_closed;            /* conn. closed (includes drops) */
242        u_long  tcps_segstimed;         /* segs where we tried to get rtt */
243        u_long  tcps_rttupdated;        /* times we succeeded */
244        u_long  tcps_delack;            /* delayed acks sent */
245        u_long  tcps_timeoutdrop;       /* conn. dropped in rxmt timeout */
246        u_long  tcps_rexmttimeo;        /* retransmit timeouts */
247        u_long  tcps_persisttimeo;      /* persist timeouts */
248        u_long  tcps_keeptimeo;         /* keepalive timeouts */
249        u_long  tcps_keepprobe;         /* keepalive probes sent */
250        u_long  tcps_keepdrops;         /* connections dropped in keepalive */
251
252        u_long  tcps_sndtotal;          /* total packets sent */
253        u_long  tcps_sndpack;           /* data packets sent */
254        u_long  tcps_sndbyte;           /* data bytes sent */
255        u_long  tcps_sndrexmitpack;     /* data packets retransmitted */
256        u_long  tcps_sndrexmitbyte;     /* data bytes retransmitted */
257        u_long  tcps_sndacks;           /* ack-only packets sent */
258        u_long  tcps_sndprobe;          /* window probes sent */
259        u_long  tcps_sndurg;            /* packets sent with URG only */
260        u_long  tcps_sndwinup;          /* window update-only packets sent */
261        u_long  tcps_sndctrl;           /* control (SYN|FIN|RST) packets sent */
262
263        u_long  tcps_rcvtotal;          /* total packets received */
264        u_long  tcps_rcvpack;           /* packets received in sequence */
265        u_long  tcps_rcvbyte;           /* bytes received in sequence */
266        u_long  tcps_rcvbadsum;         /* packets received with ccksum errs */
267        u_long  tcps_rcvbadoff;         /* packets received with bad offset */
268        u_long  tcps_rcvshort;          /* packets received too short */
269        u_long  tcps_rcvduppack;        /* duplicate-only packets received */
270        u_long  tcps_rcvdupbyte;        /* duplicate-only bytes received */
271        u_long  tcps_rcvpartduppack;    /* packets with some duplicate data */
272        u_long  tcps_rcvpartdupbyte;    /* dup. bytes in part-dup. packets */
273        u_long  tcps_rcvoopack;         /* out-of-order packets received */
274        u_long  tcps_rcvoobyte;         /* out-of-order bytes received */
275        u_long  tcps_rcvpackafterwin;   /* packets with data after window */
276        u_long  tcps_rcvbyteafterwin;   /* bytes rcvd after window */
277        u_long  tcps_rcvafterclose;     /* packets rcvd after "close" */
278        u_long  tcps_rcvwinprobe;       /* rcvd window probe packets */
279        u_long  tcps_rcvdupack;         /* rcvd duplicate acks */
280        u_long  tcps_rcvacktoomuch;     /* rcvd acks for unsent data */
281        u_long  tcps_rcvackpack;        /* rcvd ack packets */
282        u_long  tcps_rcvackbyte;        /* bytes acked by rcvd acks */
283        u_long  tcps_rcvwinupd;         /* rcvd window update packets */
284        u_long  tcps_pawsdrop;          /* segments dropped due to PAWS */
285        u_long  tcps_predack;           /* times hdr predict ok for acks */
286        u_long  tcps_preddat;           /* times hdr predict ok for data pkts */
287        u_long  tcps_pcbcachemiss;
288        u_long  tcps_cachedrtt;         /* times cached RTT in route updated */
289        u_long  tcps_cachedrttvar;      /* times cached rttvar updated */
290        u_long  tcps_cachedssthresh;    /* times cached ssthresh updated */
291        u_long  tcps_usedrtt;           /* times RTT initialized from route */
292        u_long  tcps_usedrttvar;        /* times RTTVAR initialized from rt */
293        u_long  tcps_usedssthresh;      /* times ssthresh initialized from rt*/
294        u_long  tcps_persistdrop;       /* timeout in persist state */
295        u_long  tcps_badsyn;            /* bogus SYN, e.g. premature ACK */
296        u_long  tcps_mturesent;         /* resends due to MTU discovery */
297        u_long  tcps_listendrop;        /* listen queue overflows */
298};
299
300/*
301 * Names for TCP sysctl objects
302 */
303#define TCPCTL_DO_RFC1323       1       /* use RFC-1323 extensions */
304#define TCPCTL_DO_RFC1644       2       /* use RFC-1644 extensions */
305#define TCPCTL_MSSDFLT          3       /* MSS default */
306#define TCPCTL_STATS            4       /* statistics (read-only) */
307#define TCPCTL_RTTDFLT          5       /* default RTT estimate */
308#define TCPCTL_KEEPIDLE         6       /* keepalive idle timer */
309#define TCPCTL_KEEPINTVL        7       /* interval to send keepalives */
310#define TCPCTL_SENDSPACE        8       /* send buffer space */
311#define TCPCTL_RECVSPACE        9       /* receive buffer space */
312#define TCPCTL_KEEPINIT         10      /* receive buffer space */
313#define TCPCTL_MAXID            11
314
315#define TCPCTL_NAMES { \
316        { 0, 0 }, \
317        { "rfc1323", CTLTYPE_INT }, \
318        { "rfc1644", CTLTYPE_INT }, \
319        { "mssdflt", CTLTYPE_INT }, \
320        { "stats", CTLTYPE_STRUCT }, \
321        { "rttdflt", CTLTYPE_INT }, \
322        { "keepidle", CTLTYPE_INT }, \
323        { "keepintvl", CTLTYPE_INT }, \
324        { "sendspace", CTLTYPE_INT }, \
325        { "recvspace", CTLTYPE_INT }, \
326        { "keepinit", CTLTYPE_INT }, \
327}
328
329#ifdef KERNEL
330extern  struct inpcbhead tcb;           /* head of queue of active tcpcb's */
331extern  struct inpcbinfo tcbinfo;
332extern  struct tcpstat tcpstat; /* tcp statistics */
333extern  int tcp_mssdflt;        /* XXX */
334extern  u_long tcp_now;         /* for RFC 1323 timestamps */
335
336void     tcp_canceltimers __P((struct tcpcb *));
337struct tcpcb *
338         tcp_close __P((struct tcpcb *));
339void     tcp_ctlinput __P((int, struct sockaddr *, void *));
340int      tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **));
341struct tcpcb *
342         tcp_drop __P((struct tcpcb *, int));
343void     tcp_drain __P((void));
344void     tcp_fasttimo __P((void));
345struct rmxp_tao *
346         tcp_gettaocache __P((struct inpcb *));
347void     tcp_init __P((void));
348void     tcp_input __P((struct mbuf *, int));
349void     tcp_mss __P((struct tcpcb *, int));
350int      tcp_mssopt __P((struct tcpcb *));
351void     tcp_mtudisc __P((struct inpcb *, int));
352struct tcpcb *
353         tcp_newtcpcb __P((struct inpcb *));
354int      tcp_output __P((struct tcpcb *));
355void     tcp_quench __P((struct inpcb *, int));
356void     tcp_respond __P((struct tcpcb *,
357            struct tcpiphdr *, struct mbuf *, u_long, u_long, int));
358struct rtentry *
359         tcp_rtlookup __P((struct inpcb *));
360void     tcp_setpersist __P((struct tcpcb *));
361void     tcp_slowtimo __P((void));
362struct tcpiphdr *
363         tcp_template __P((struct tcpcb *));
364struct tcpcb *
365         tcp_timers __P((struct tcpcb *, int));
366void     tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int));
367
368extern  struct pr_usrreqs tcp_usrreqs;
369extern  u_long tcp_sendspace;
370extern  u_long tcp_recvspace;
371
372#endif /* KERNEL */
373
374#endif /* _NETINET_TCP_VAR_H_ */
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