- Merge aicom-network-branch (still without the NDIS stuff)
[reactos.git] / reactos / lib / drivers / oskittcp / oskittcp / tcp_subr.c
1 /*
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993
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_subr.c 8.1 (Berkeley) 6/10/93
34 */
35
36 #include <sys/param.h>
37 #include <sys/proc.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/malloc.h>
41 #include <sys/mbuf.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 #include <sys/protosw.h>
45 #include <sys/errno.h>
46 #include <sys/queue.h>
47
48 #include <net/route.h>
49 #include <net/if.h>
50
51 #include <netinet/in.h>
52 #include <netinet/in_systm.h>
53 #include <netinet/ip.h>
54 #include <netinet/in_pcb.h>
55 #include <netinet/in_var.h>
56 #include <netinet/ip_var.h>
57 #include <netinet/ip_icmp.h>
58 #include <netinet/tcp.h>
59 #include <netinet/tcp_fsm.h>
60 #include <netinet/tcp_seq.h>
61 #include <netinet/tcp_timer.h>
62 #include <netinet/tcp_var.h>
63 #include <netinet/tcpip.h>
64 #ifdef TCPDEBUG
65 #include <netinet/tcp_debug.h>
66 #endif
67 #include <oskittcp.h>
68
69 /* patchable/settable parameters for tcp */
70 int tcp_mssdflt = TCP_MSS;
71 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
72 int tcp_do_rfc1323 = 1;
73 int tcp_do_rfc1644 = 1;
74 static void tcp_cleartaocache(void);
75
76 /*
77 * Target size of TCP PCB hash table. Will be rounded down to a prime
78 * number.
79 */
80 #ifndef TCBHASHSIZE
81 #define TCBHASHSIZE 128
82 #endif
83
84 /*
85 * Tcp initialization
86 */
87 void
88 tcp_init()
89 {
90
91 tcp_iss = boottime.tv_sec; /* wrong */
92 tcp_ccgen = 1;
93 tcp_cleartaocache();
94 LIST_INIT(&tcb);
95 tcbinfo.listhead = &tcb;
96 tcbinfo.hashbase = phashinit(TCBHASHSIZE, M_PCB, &tcbinfo.hashsize);
97 if (max_protohdr < sizeof(struct tcpiphdr))
98 max_protohdr = sizeof(struct tcpiphdr);
99 if (max_linkhdr + sizeof(struct tcpiphdr) > MHLEN)
100 panic("tcp_init");
101 }
102
103 /*
104 * Create template to be used to send tcp packets on a connection.
105 * Call after host entry created, allocates an mbuf and fills
106 * in a skeletal tcp/ip header, minimizing the amount of work
107 * necessary when the connection is used.
108 */
109 struct tcpiphdr *
110 tcp_template(tp)
111 struct tcpcb *tp;
112 {
113 register struct inpcb *inp = tp->t_inpcb;
114 register struct mbuf *m;
115 register struct tcpiphdr *n;
116
117 if ((n = tp->t_template) == 0) {
118 m = m_get(M_DONTWAIT, MT_HEADER);
119 OS_DbgPrint(OSK_MID_TRACE,("tp->t_template = %x\n", m));
120 if (m == NULL)
121 return (0);
122 m->m_len = sizeof (struct tcpiphdr);
123 n = mtod(m, struct tcpiphdr *);
124 }
125 n->ti_next = n->ti_prev = 0;
126 n->ti_x1 = 0;
127 n->ti_pr = IPPROTO_TCP;
128 n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
129 n->ti_src = inp->inp_laddr;
130 OS_DbgPrint(OSK_MID_TRACE,("INP_LADDR = %x\n", n->ti_src));
131 n->ti_dst = inp->inp_faddr;
132 n->ti_sport = inp->inp_lport;
133 n->ti_dport = inp->inp_fport;
134 n->ti_seq = 0;
135 n->ti_ack = 0;
136 n->ti_x2 = 0;
137 n->ti_off = 5;
138 n->ti_flags = 0;
139 n->ti_win = 0;
140 n->ti_sum = 0;
141 n->ti_urp = 0;
142 return (n);
143 }
144
145 /*
146 * Send a single message to the TCP at address specified by
147 * the given TCP/IP header. If m == 0, then we make a copy
148 * of the tcpiphdr at ti and send directly to the addressed host.
149 * This is used to force keep alive messages out using the TCP
150 * template for a connection tp->t_template. If flags are given
151 * then we send a message back to the TCP which originated the
152 * segment ti, and discard the mbuf containing it and any other
153 * attached mbufs.
154 *
155 * In any case the ack and sequence number of the transmitted
156 * segment are as specified by the parameters.
157 */
158 void
159 tcp_respond(tp, ti, m, ack, seq, flags)
160 struct tcpcb *tp;
161 register struct tcpiphdr *ti;
162 register struct mbuf *m;
163 tcp_seq ack, seq;
164 int flags;
165 {
166 register int tlen;
167 int win = 0;
168 struct route *ro = 0;
169
170 if (tp) {
171 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
172 ro = &tp->t_inpcb->inp_route;
173 }
174 if (m == 0) {
175 m = m_gethdr(M_DONTWAIT, MT_HEADER);
176 if (m == NULL)
177 return;
178 #ifdef TCP_COMPAT_42
179 tlen = 1;
180 #else
181 tlen = 0;
182 #endif
183 m->m_data += max_linkhdr;
184 *mtod(m, struct tcpiphdr *) = *ti;
185 ti = mtod(m, struct tcpiphdr *);
186 flags = TH_ACK;
187 } else {
188 m_freem(m->m_next);
189 m->m_next = 0;
190 m->m_data = (caddr_t)ti;
191 m->m_len = sizeof (struct tcpiphdr);
192 tlen = 0;
193 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
194 xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_long);
195 xchg(ti->ti_dport, ti->ti_sport, u_short);
196 #undef xchg
197 }
198 ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen));
199 tlen += sizeof (struct tcpiphdr);
200 m->m_len = tlen;
201 m->m_pkthdr.len = tlen;
202 m->m_pkthdr.rcvif = (struct ifnet *) 0;
203 ti->ti_next = ti->ti_prev = 0;
204 ti->ti_x1 = 0;
205 ti->ti_seq = htonl(seq);
206 ti->ti_ack = htonl(ack);
207 ti->ti_x2 = 0;
208 ti->ti_off = sizeof (struct tcphdr) >> 2;
209 ti->ti_flags = flags;
210 if (tp)
211 ti->ti_win = htons((u_short) (win >> tp->rcv_scale));
212 else
213 ti->ti_win = htons((u_short)win);
214 ti->ti_urp = 0;
215 ti->ti_sum = 0;
216 ti->ti_sum = in_cksum(m, tlen);
217 ((struct ip *)ti)->ip_len = tlen;
218 ((struct ip *)ti)->ip_ttl = ip_defttl;
219 #ifdef TCPDEBUG
220 if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
221 tcp_trace(TA_OUTPUT, 0, tp, ti, 0);
222 #endif
223 (void) ip_output(m, NULL, ro, 0, NULL);
224 }
225
226 /*
227 * Create a new TCP control block, making an
228 * empty reassembly queue and hooking it to the argument
229 * protocol control block.
230 */
231 struct tcpcb *
232 tcp_newtcpcb(inp)
233 struct inpcb *inp;
234 {
235 register struct tcpcb *tp;
236
237 tp = malloc(sizeof(*tp), M_PCB, M_NOWAIT);
238 if (tp == NULL)
239 return ((struct tcpcb *)0);
240 bzero((char *) tp, sizeof(struct tcpcb));
241 tp->seg_next = tp->seg_prev = (struct tcpiphdr *)tp;
242 tp->t_maxseg = tp->t_maxopd = tcp_mssdflt;
243
244 if (tcp_do_rfc1323)
245 tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
246 if (tcp_do_rfc1644)
247 tp->t_flags |= TF_REQ_CC;
248 tp->t_inpcb = inp;
249 /*
250 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
251 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
252 * reasonable initial retransmit time.
253 */
254 tp->t_srtt = TCPTV_SRTTBASE;
255 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 2;
256 tp->t_rttmin = TCPTV_MIN;
257 TCPT_RANGESET(tp->t_rxtcur,
258 ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
259 TCPTV_MIN, TCPTV_REXMTMAX);
260 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
261 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
262 inp->inp_ip.ip_ttl = ip_defttl;
263 inp->inp_ppcb = (caddr_t)tp;
264 return (tp);
265 }
266
267 /*
268 * Drop a TCP connection, reporting
269 * the specified error. If connection is synchronized,
270 * then send a RST to peer.
271 */
272 struct tcpcb *
273 tcp_drop(tp, errno)
274 register struct tcpcb *tp;
275 int errno;
276 {
277 struct socket *so = tp->t_inpcb->inp_socket;
278
279 if (TCPS_HAVERCVDSYN(tp->t_state)) {
280 tp->t_state = TCPS_CLOSED;
281 (void) tcp_output(tp);
282 tcpstat.tcps_drops++;
283 } else
284 tcpstat.tcps_conndrops++;
285 if (errno == ETIMEDOUT && tp->t_softerror)
286 errno = tp->t_softerror;
287 so->so_error = errno;
288 return (tcp_close(tp));
289 }
290
291 /*
292 * Close a TCP control block:
293 * discard all space held by the tcp
294 * discard internet protocol block
295 * wake up any sleepers
296 */
297 struct tcpcb *
298 tcp_close(tp)
299 register struct tcpcb *tp;
300 {
301 register struct tcpiphdr *t;
302 struct inpcb *inp = tp->t_inpcb;
303 struct socket *so = inp->inp_socket;
304 register struct mbuf *m;
305 #ifdef RTV_RTT
306 register struct rtentry *rt;
307
308 /*
309 * If we got enough samples through the srtt filter,
310 * save the rtt and rttvar in the routing entry.
311 * 'Enough' is arbitrarily defined as the 16 samples.
312 * 16 samples is enough for the srtt filter to converge
313 * to within 5% of the correct value; fewer samples and
314 * we could save a very bogus rtt.
315 *
316 * Don't update the default route's characteristics and don't
317 * update anything that the user "locked".
318 */
319 if (tp->t_rttupdated >= 16 &&
320 (rt = inp->inp_route.ro_rt) &&
321 ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr != INADDR_ANY) {
322 register u_long i = 0;
323
324 if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
325 i = tp->t_srtt *
326 (RTM_RTTUNIT / (PR_SLOWHZ * TCP_RTT_SCALE));
327 if (rt->rt_rmx.rmx_rtt && i)
328 /*
329 * filter this update to half the old & half
330 * the new values, converting scale.
331 * See route.h and tcp_var.h for a
332 * description of the scaling constants.
333 */
334 rt->rt_rmx.rmx_rtt =
335 (rt->rt_rmx.rmx_rtt + i) / 2;
336 else
337 rt->rt_rmx.rmx_rtt = i;
338 tcpstat.tcps_cachedrtt++;
339 }
340 if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
341 i = tp->t_rttvar *
342 (RTM_RTTUNIT / (PR_SLOWHZ * TCP_RTTVAR_SCALE));
343 if (rt->rt_rmx.rmx_rttvar && i)
344 rt->rt_rmx.rmx_rttvar =
345 (rt->rt_rmx.rmx_rttvar + i) / 2;
346 else
347 rt->rt_rmx.rmx_rttvar = i;
348 tcpstat.tcps_cachedrttvar++;
349 }
350 /*
351 * update the pipelimit (ssthresh) if it has been updated
352 * already or if a pipesize was specified & the threshhold
353 * got below half the pipesize. I.e., wait for bad news
354 * before we start updating, then update on both good
355 * and bad news.
356 */
357 if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 &&
358 ((i = tp->snd_ssthresh) != 0) && rt->rt_rmx.rmx_ssthresh) ||
359 i < (rt->rt_rmx.rmx_sendpipe / 2)) {
360 /*
361 * convert the limit from user data bytes to
362 * packets then to packet data bytes.
363 */
364 i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
365 if (i < 2)
366 i = 2;
367 i *= (u_long)(tp->t_maxseg + sizeof (struct tcpiphdr));
368 if (rt->rt_rmx.rmx_ssthresh)
369 rt->rt_rmx.rmx_ssthresh =
370 (rt->rt_rmx.rmx_ssthresh + i) / 2;
371 else
372 rt->rt_rmx.rmx_ssthresh = i;
373 tcpstat.tcps_cachedssthresh++;
374 }
375 }
376 #endif /* RTV_RTT */
377 /* free the reassembly queue, if any */
378 t = tp->seg_next;
379 while (t != (struct tcpiphdr *)tp) {
380 t = (struct tcpiphdr *)t->ti_next;
381 m = REASS_MBUF((struct tcpiphdr *)t->ti_prev);
382 remque(t->ti_prev);
383 m_freem(m);
384 }
385 if (tp->t_template)
386 (void) m_free(dtom(tp->t_template));
387 free(tp, M_PCB);
388 inp->inp_ppcb = 0;
389 soisdisconnected(so);
390 in_pcbdetach(inp);
391 tcpstat.tcps_closed++;
392 return ((struct tcpcb *)0);
393 }
394
395 void
396 tcp_drain()
397 {
398
399 }
400
401 /*
402 * Notify a tcp user of an asynchronous error;
403 * store error as soft error, but wake up user
404 * (for now, won't do anything until can select for soft error).
405 */
406 void
407 tcp_notify(inp, error)
408 struct inpcb *inp;
409 int error;
410 {
411 register struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb;
412 register struct socket *so = inp->inp_socket;
413
414 /*
415 * Ignore some errors if we are hooked up.
416 * If connection hasn't completed, has retransmitted several times,
417 * and receives a second error, give up now. This is better
418 * than waiting a long time to establish a connection that
419 * can never complete.
420 */
421 if (tp->t_state == TCPS_ESTABLISHED &&
422 (error == EHOSTUNREACH || error == ENETUNREACH ||
423 error == EHOSTDOWN)) {
424 return;
425 } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
426 tp->t_softerror)
427 so->so_error = error;
428 else
429 tp->t_softerror = error;
430 wakeup( so, (caddr_t) &so->so_timeo);
431 sorwakeup(so);
432 sowwakeup(so);
433 }
434
435 void
436 tcp_ctlinput(cmd, sa, ip)
437 int cmd;
438 struct sockaddr *sa;
439 register struct ip *ip;
440 {
441 register struct tcphdr *th;
442 void (*notify) __P((struct inpcb *, int)) = tcp_notify;
443
444 if (cmd == PRC_QUENCH)
445 notify = tcp_quench;
446 #if 1
447 else if (cmd == PRC_MSGSIZE)
448 notify = tcp_mtudisc;
449 #endif
450 else if (!PRC_IS_REDIRECT(cmd) &&
451 ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0))
452 return;
453 if (ip) {
454 th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
455 in_pcbnotify(&tcb, sa, th->th_dport, ip->ip_src, th->th_sport,
456 cmd, notify);
457 } else
458 in_pcbnotify(&tcb, sa, 0, zeroin_addr, 0, cmd, notify);
459 }
460
461 /*
462 * When a source quench is received, close congestion window
463 * to one segment. We will gradually open it again as we proceed.
464 */
465 void
466 tcp_quench(inp, errno)
467 struct inpcb *inp;
468 int errno;
469 {
470 struct tcpcb *tp = intotcpcb(inp);
471
472 if (tp)
473 tp->snd_cwnd = tp->t_maxseg;
474 }
475
476 #if 1
477 /*
478 * When `need fragmentation' ICMP is received, update our idea of the MSS
479 * based on the new value in the route. Also nudge TCP to send something,
480 * since we know the packet we just sent was dropped.
481 * This duplicates some code in the tcp_mss() function in tcp_input.c.
482 */
483 void
484 tcp_mtudisc(inp, errno)
485 struct inpcb *inp;
486 int errno;
487 {
488 struct tcpcb *tp = intotcpcb(inp);
489 struct rtentry *rt;
490 struct rmxp_tao *taop;
491 struct socket *so = inp->inp_socket;
492 int offered;
493 int mss;
494
495 if (tp) {
496 rt = tcp_rtlookup(inp);
497 if (!rt || !rt->rt_rmx.rmx_mtu) {
498 tp->t_maxopd = tp->t_maxseg = tcp_mssdflt;
499 return;
500 }
501 taop = rmx_taop(rt->rt_rmx);
502 offered = taop->tao_mssopt;
503 mss = rt->rt_rmx.rmx_mtu - sizeof(struct tcpiphdr);
504 if (offered)
505 mss = min(mss, offered);
506 /*
507 * XXX - The above conditional probably violates the TCP
508 * spec. The problem is that, since we don't know the
509 * other end's MSS, we are supposed to use a conservative
510 * default. But, if we do that, then MTU discovery will
511 * never actually take place, because the conservative
512 * default is much less than the MTUs typically seen
513 * on the Internet today. For the moment, we'll sweep
514 * this under the carpet.
515 *
516 * The conservative default might not actually be a problem
517 * if the only case this occurs is when sending an initial
518 * SYN with options and data to a host we've never talked
519 * to before. Then, they will reply with an MSS value which
520 * will get recorded and the new parameters should get
521 * recomputed. For Further Study.
522 */
523 if (tp->t_maxopd <= mss)
524 return;
525 tp->t_maxopd = mss;
526
527 if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
528 (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP)
529 mss -= TCPOLEN_TSTAMP_APPA;
530 if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC &&
531 (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC)
532 mss -= TCPOLEN_CC_APPA;
533 #if (MCLBYTES & (MCLBYTES - 1)) == 0
534 if (mss > MCLBYTES)
535 mss &= ~(MCLBYTES-1);
536 #else
537 if (mss > MCLBYTES)
538 mss = mss / MCLBYTES * MCLBYTES;
539 #endif
540 if (so->so_snd.sb_hiwat < mss)
541 mss = so->so_snd.sb_hiwat;
542
543 tp->t_maxseg = mss;
544
545 tcpstat.tcps_mturesent++;
546 tp->t_rtt = 0;
547 tp->snd_nxt = tp->snd_una;
548 tcp_output(tp);
549 }
550 }
551 #endif
552
553 /*
554 * Look-up the routing entry to the peer of this inpcb. If no route
555 * is found and it cannot be allocated the return NULL. This routine
556 * is called by TCP routines that access the rmx structure and by tcp_mss
557 * to get the interface MTU.
558 */
559 struct rtentry *
560 tcp_rtlookup(inp)
561 struct inpcb *inp;
562 {
563 struct route *ro;
564 struct rtentry *rt;
565
566 ro = &inp->inp_route;
567 rt = ro->ro_rt;
568 if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
569 /* No route yet, so try to acquire one */
570 if (inp->inp_faddr.s_addr != INADDR_ANY) {
571 ro->ro_dst.sa_family = AF_INET;
572 ro->ro_dst.sa_len = sizeof(ro->ro_dst);
573 ((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
574 inp->inp_faddr;
575 rtalloc(ro);
576 rt = ro->ro_rt;
577 }
578 }
579 return rt;
580 }
581
582 /*
583 * Return a pointer to the cached information about the remote host.
584 * The cached information is stored in the protocol specific part of
585 * the route metrics.
586 */
587 struct rmxp_tao *
588 tcp_gettaocache(inp)
589 struct inpcb *inp;
590 {
591 struct rtentry *rt = tcp_rtlookup(inp);
592
593 /* Make sure this is a host route and is up. */
594 if (rt == NULL ||
595 (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST))
596 return NULL;
597
598 return rmx_taop(rt->rt_rmx);
599 }
600
601 /*
602 * Clear all the TAO cache entries, called from tcp_init.
603 *
604 * XXX
605 * This routine is just an empty one, because we assume that the routing
606 * routing tables are initialized at the same time when TCP, so there is
607 * nothing in the cache left over.
608 */
609 static void
610 tcp_cleartaocache(void)
611 { }