xref: /csrg-svn/sys/netns/spp_usrreq.c (revision 24330)
1 /*
2  * Copyright (c) 1982 Regents of the University of California.
3  * All rights reserved.  The Berkeley software License Agreement
4  * specifies the terms and conditions for redistribution.
5  *
6  *	@(#)spp_usrreq.c	6.8 (Berkeley) 08/17/85
7  */
8 
9 #include "param.h"
10 #include "dir.h"
11 #include "user.h"
12 #include "mbuf.h"
13 #include "protosw.h"
14 #include "socket.h"
15 #include "socketvar.h"
16 #include "errno.h"
17 
18 #include "../net/if.h"
19 #include "../net/route.h"
20 #include "../netinet/tcp_fsm.h"
21 #include "../netinet/tcp_timer.h"
22 
23 #include "ns.h"
24 #include "ns_pcb.h"
25 #include "idp.h"
26 #include "idp_var.h"
27 #include "ns_error.h"
28 #include "sp.h"
29 #include "spidp.h"
30 #include "spp_var.h"
31 #include "spp_debug.h"
32 
33 /*
34  * SP protocol implementation.
35  */
36 spp_init()
37 {
38 
39 	spp_iss = 1; /* WRONG !! should fish it out of TODR */
40 }
41 struct spidp spp_savesi;
42 int traceallspps = 0;
43 extern int sppconsdebug;
44 
45 int spp_hardnosed;
46 spp_input(m, nsp)
47 	register struct mbuf *m;
48 	register struct nspcb *nsp;
49 {
50 	register struct sppcb *cb;
51 	register struct spidp *si = mtod(m, struct spidp *);
52 	register struct socket *so;
53 	short ostate;
54 	int dropsocket = 0;
55 
56 
57 	if (nsp == 0) {
58 		panic("No nspcb in spp_input\n");
59 		return;
60 	}
61 
62 	cb = nstosppcb(nsp);
63 	if (cb == 0) goto bad;
64 
65 	if (m->m_len < sizeof(*si)) {
66 		if ((m = m_pullup(m, sizeof(*si))) == 0) {
67 			spp_istat.hdrops++;
68 			return;
69 		}
70 		si = mtod(m, struct spidp *);
71 	}
72 	si->si_seq = ntohs(si->si_seq);
73 	si->si_ack = ntohs(si->si_ack);
74 	si->si_alo = ntohs(si->si_alo);
75 
76 	so = nsp->nsp_socket;
77 	if (so->so_options & SO_DEBUG || traceallspps) {
78 		ostate = cb->s_state;
79 		spp_savesi = *si;
80 	}
81 	if (so->so_options & SO_ACCEPTCONN) {
82 		so = sonewconn(so);
83 		if (so == 0) {
84 			spp_istat.nonucn++;
85 			goto drop;
86 		}
87 		/*
88 		 * This is ugly, but ....
89 		 *
90 		 * Mark socket as temporary until we're
91 		 * committed to keeping it.  The code at
92 		 * ``drop'' and ``dropwithreset'' check the
93 		 * flag dropsocket to see if the temporary
94 		 * socket created here should be discarded.
95 		 * We mark the socket as discardable until
96 		 * we're committed to it below in TCPS_LISTEN.
97 		 */
98 		dropsocket++;
99 		nsp = (struct nspcb *)so->so_pcb;
100 		nsp->nsp_laddr = si->si_dna;
101 		cb = nstosppcb(nsp);
102 		cb->s_state = TCPS_LISTEN;
103 	}
104 
105 	/*
106 	 * Packet received on connection.
107 	 * reset idle time and keep-alive timer;
108 	 */
109 	cb->s_idle = 0;
110 	cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
111 
112 	switch (cb->s_state) {
113 
114 	case TCPS_LISTEN:{
115 		struct mbuf *am;
116 		register struct sockaddr_ns *sns;
117 		struct ns_addr laddr;
118 
119 		/*
120 		 * If somebody here was carying on a conversation
121 		 * and went away, and his pen pal thinks he can
122 		 * still talk, we get the misdirected packet.
123 		 */
124 		if (spp_hardnosed && (si->si_did != 0 || si->si_seq != 0)) {
125 			spp_istat.gonawy++;
126 			goto dropwithreset;
127 		}
128 		am = m_get(M_DONTWAIT, MT_SONAME);
129 		if (am == NULL)
130 			goto drop;
131 		am->m_len = sizeof (struct sockaddr_ns);
132 		sns = mtod(am, struct sockaddr_ns *);
133 		sns->sns_family = AF_NS;
134 		sns->sns_addr = si->si_sna;
135 		laddr = nsp->nsp_laddr;
136 		if (ns_nullhost(laddr))
137 			nsp->nsp_laddr = si->si_dna;
138 		if (ns_pcbconnect(nsp, am)) {
139 			nsp->nsp_laddr = laddr;
140 			(void) m_free(am);
141 			spp_istat.noconn++;
142 			goto drop;
143 		}
144 		(void) m_free(am);
145 		cb->s_state = TCPS_SYN_RECEIVED;
146 		spp_template(cb);
147 		cb->s_did = si->si_sid;
148 		cb->s_rack = si->si_ack;
149 		cb->s_ralo = si->si_alo;
150 		cb->s_flags |= SF_AK;
151 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
152 		dropsocket = 0;		/* committed to socket */
153 		}
154 		break;
155 
156 	/*
157 	 * This state means that we have gotten a response
158 	 * to our attempt to establish a connection.
159 	 * We fill in the data from the other side,
160 	 * telling us which port to respond to, instead of the well-
161 	 * known one we might have sent to in the first place.
162 	 * We also require that this is a response to our
163 	 * connection id.
164 	 */
165 	case TCPS_SYN_SENT:
166 		if (si->si_did!=cb->s_sid) {
167 			spp_istat.notme++;
168 			goto drop;
169 		}
170 		cb->s_did = si->si_sid;
171 		cb->s_rack = si->si_ack;
172 		cb->s_ralo = si->si_alo;
173 		cb->s_dport = nsp->nsp_fport =  si->si_sport;
174 		cb->s_timer[TCPT_REXMT] = 0;
175 		cb->s_flags |= SF_AK;
176 		soisconnected(so);
177 		cb->s_state = TCPS_ESTABLISHED;
178 		break;
179 	/*
180 	 * This state means that we have heard a response
181 	 * to our acceptance of their connection
182 	 * It is probably logically unnecessary in this
183 	 * implementation.
184 	 */
185 	 case TCPS_SYN_RECEIVED:
186 		if (si->si_did!=cb->s_sid) {
187 			spp_istat.wrncon++;
188 			goto drop;
189 		}
190 		nsp->nsp_fport =  si->si_sport;
191 		cb->s_timer[TCPT_REXMT] = 0;
192 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
193 		soisconnected(so);
194 		cb->s_state = TCPS_ESTABLISHED;
195 	}
196 	if (so->so_options & SO_DEBUG || traceallspps)
197 		spp_trace(SA_INPUT, (u_char)ostate, cb, &spp_savesi, 0);
198 
199 	m->m_len -= sizeof (struct idp);
200 	m->m_off += sizeof (struct idp);
201 
202 	if (spp_reass(cb,si)) {
203 		goto drop;
204 	}
205 	(void) spp_output(cb,(struct mbuf *)0);
206 	return;
207 
208 dropwithreset:
209 	if (dropsocket)
210 		(void) soabort(so);
211 	si->si_seq = ntohs(si->si_seq);
212 	si->si_ack = ntohs(si->si_ack);
213 	si->si_alo = ntohs(si->si_alo);
214 	ns_error(dtom(si), NS_ERR_NOSOCK, 0);
215 	if (cb->s_nspcb->nsp_socket->so_options & SO_DEBUG || traceallspps)
216 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
217 	return;
218 
219 drop:
220 bad:
221 	if (cb == 0 || cb->s_nspcb->nsp_socket->so_options & SO_DEBUG || traceallspps)
222 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
223 	m_freem(m);
224 }
225 
226 /*
227  * This is structurally similar to the tcp reassembly routine
228  * but its function is somewhat different:  It merely queues
229  * packets up, and suppresses duplicates.
230  */
231 spp_reass(cb,si)
232 register struct sppcb *cb;
233 register struct spidp *si;
234 {
235 	register struct spidp_q *q;
236 	register struct mbuf *m;
237 	struct socket *so = cb->s_nspcb->nsp_socket;
238 	struct sockbuf *sb = & (so->so_rcv);
239 	char packetp = cb->s_flags & SF_HI;
240 	char wakeup = 0;
241 
242 
243 	if (si == SI(0))
244 		goto present;
245 	/*
246 	 * Update our news from them.
247 	 */
248 	if (si->si_cc & SP_SA)
249 		cb->s_flags |= SF_DELACK;
250 	if (SSEQ_GT(si->si_ack,cb->s_rack)) {
251 		cb->s_rack = si->si_ack;
252 		cb->s_timer[TCPT_REXMT] = 0;
253 
254 		/*
255 		 * If transmit timer is running and timed sequence
256 		 * number was acked, update smoothed round trip time.
257 		 */
258 		if (cb->s_rtt && SSEQ_GT(si->si_ack, cb->s_rtseq)) {
259 			if (cb->s_srtt == 0)
260 				cb->s_srtt = cb->s_rtt;
261 			else
262 				cb->s_srtt =
263 				    tcp_alpha * cb->s_srtt +
264 				    (1 - tcp_alpha) * cb->s_rtt;
265 			cb->s_rtt = 0;
266 		}
267 	}
268 	if (SSEQ_GT(si->si_alo,cb->s_ralo)) {
269 		cb->s_ralo = si->si_alo;
270 		cb->s_timer[TCPT_PERSIST] = 0;
271 	}
272 	/*
273 	 * If this is a system packet, we don't need to
274 	 * queue it up, and won't update acknowledge #
275 	 */
276 	if (si->si_cc & SP_SP) {
277 		m_freem(dtom(si));
278 		return (0);
279 	}
280 
281 	/*
282 	 * If this packet number has a sequence number less
283 	 * than that of the first packet not yet seen coming
284 	 * from them, this must be a duplicate, so drop.
285 	 */
286 	if (SSEQ_LT(si->si_seq,cb->s_ack)) {
287 		spp_istat.bdreas++;
288 		if (si->si_seq == cb->s_ack-1)
289 			spp_istat.lstdup++;
290 		return (1);
291 	}
292 	/*
293 	 * If this packet number is higher than that which
294 	 * we have allocated refuse it, unless urgent
295 	 */
296 	if (SSEQ_GT(si->si_seq,cb->s_alo) && (!(si->si_cc & SP_OB))) {
297 		spp_istat.notyet++;
298 		return (1);
299 	}
300 	/*
301 	 * If this packet is urgent, inform process
302 	 */
303 	if (si->si_cc & SP_OB) {
304 		cb->s_iobc = ((char *)si)[1 + sizeof(*si)];
305 		sohasoutofband(so);
306 	}
307 
308 	/*
309 	 * Loop through all packets queued up to insert in
310 	 * appropriate sequence.
311 	 */
312 
313 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
314 	    if (si->si_seq == SI(q)->si_seq) return (1); /*duplicate */
315 	    if (SSEQ_LT(si->si_seq,SI(q)->si_seq)) break;
316 	}
317 	insque(si,q->si_prev);
318 
319 present:
320 #define SPINC sizeof(struct sphdr)
321 	/*
322 	 * Loop through all packets queued up to update acknowledge
323 	 * number, and present all acknowledged data to user;
324 	 * If in packet interface mode, show packet headers.
325 	 */
326 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
327 		  if (SI(q)->si_seq == cb->s_ack) {
328 			cb->s_ack++;
329 			m = dtom(q);
330 			if (SI(q)->si_cc & SP_OB) {
331 				if (sb->sb_cc)
332 					so->so_oobmark = sb->sb_cc;
333 				else
334 					so->so_state |= SS_RCVATMARK;
335 			}
336 			q = q->si_prev;
337 			remque(q->si_next);
338 			wakeup = 1;
339 			if (packetp) {
340 				sbappendrecord(sb,m);
341 			} else {
342 				cb->s_rhdr = *mtod(m, struct sphdr *);
343 				m->m_off += SPINC;
344 				m->m_len -= SPINC;
345 				sbappend(sb,m);
346 			}
347 		  } else
348 			break;
349 	}
350 	if (wakeup) sorwakeup(so);
351 	return (0);
352 }
353 
354 spp_ctlinput(cmd, arg)
355 	int cmd;
356 	caddr_t arg;
357 {
358 	struct ns_addr *na;
359 	extern u_char nsctlerrmap[];
360 	extern spp_abort();
361 	extern struct nspcb *idp_drop();
362 	struct ns_errp *errp;
363 	struct nspcb *nsp;
364 	int type;
365 
366 	if (cmd < 0 || cmd > PRC_NCMDS)
367 		return;
368 	type = NS_ERR_UNREACH_HOST;
369 
370 	switch (cmd) {
371 
372 	case PRC_ROUTEDEAD:
373 	case PRC_QUENCH:
374 		break;
375 
376 	case PRC_IFDOWN:
377 		na = &((struct sockaddr_ns *)arg)->sns_addr;
378 		break;
379 
380 	case PRC_HOSTDEAD:
381 	case PRC_HOSTUNREACH:
382 		na = (struct ns_addr *)arg;
383 		break;
384 
385 	default:
386 		errp = (struct ns_errp *)arg;
387 		na = &errp->ns_err_idp.idp_dna;
388 		type = errp->ns_err_num;
389 		type = ntohs((u_short)type);
390 	}
391 	switch (type) {
392 
393 	case NS_ERR_UNREACH_HOST:
394 		ns_pcbnotify(na, (int)nsctlerrmap[cmd], spp_abort, (long) 0);
395 		break;
396 
397 	case NS_ERR_TOO_BIG:
398 	case NS_ERR_NOSOCK:
399 		nsp = ns_pcblookup(na, errp->ns_err_idp.idp_sna.x_port,
400 			NS_WILDCARD);
401 		if (nsp) {
402 			if(nsp->nsp_pcb)
403 				(void) spp_drop((struct sppcb *)nsp->nsp_pcb,
404 						(int)nsctlerrmap[cmd]);
405 			else
406 				(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
407 		}
408 	}
409 }
410 
411 #ifdef notdef
412 int
413 spp_fixmtu(nsp)
414 register struct nspcb *nsp;
415 {
416 	register struct sppcb *cb = (struct sppcb *)(nsp->nsp_pcb);
417 	register struct mbuf *m;
418 	register struct spidp *si;
419 	struct ns_errp *ep;
420 	struct sockbuf *sb;
421 	int badseq, len;
422 	struct mbuf *firstbad, *m0;
423 
424 	if (cb) {
425 		/*
426 		 * The notification that we have sent
427 		 * too much is bad news -- we will
428 		 * have to go through queued up so far
429 		 * splitting ones which are too big and
430 		 * reassigning sequence numbers and checksums.
431 		 * we should then retransmit all packets from
432 		 * one above the offending packet to the last one
433 		 * we had sent (or our allocation)
434 		 * then the offending one so that the any queued
435 		 * data at our destination will be discarded.
436 		 */
437 		 ep = (struct ns_errp *)nsp->nsp_notify_param;
438 		 sb = &nsp->nsp_socket->so_snd;
439 		 cb->s_mtu = ep->ns_err_param;
440 		 badseq = SI(&ep->ns_err_idp)->si_seq;
441 		 for (m = sb->sb_mb; m; m = m->m_act) {
442 			si = mtod(m, struct spidp *);
443 			if (si->si_seq == badseq)
444 				break;
445 		 }
446 		 if (m == 0) return;
447 		 firstbad = m;
448 		 /*for (;;) {*/
449 			/* calculate length */
450 			for (m0 = m, len = 0; m ; m = m->m_next)
451 				len += m->m_len;
452 			if (len > cb->s_mtu) {
453 			}
454 		/* FINISH THIS
455 		} */
456 	}
457 }
458 #endif
459 
460 int spp_output_cnt = 0;
461 
462 spp_output(cb, m0)
463 	register struct sppcb *cb;
464 	struct mbuf *m0;
465 {
466 	struct socket *so = cb->s_nspcb->nsp_socket;
467 	register struct mbuf *m;
468 	register struct spidp *si = (struct spidp *) 0;
469 	register struct sockbuf *sb = &(so->so_snd);
470 	register int len = 0;
471 	int mtu = cb->s_mtu;
472 	int error = 0;
473 	u_short lookfor = 0;
474 	struct mbuf *mprev;
475 	extern int idpcksum;
476 
477 	if (m0) {
478 		for (m = m0; m ; m = m->m_next) {
479 			mprev = m;
480 			len += m->m_len;
481 		}
482 		if (len > mtu) {
483 			if (cb->s_flags & SF_PI) {
484 				m_freem(m0);
485 				return (EMSGSIZE);
486 			} else {
487 				int off = 0;
488 				while (len > mtu) {
489 					m = m_copy(m0, off, mtu);
490 					if (m == NULL) {
491 						m_freem(m0);
492 						return (ENOBUFS);
493 					}
494 					error = spp_output(cb, m);
495 					if (error) {
496 						m_freem(m0);
497 						return (error);
498 					}
499 					m_adj(m0, mtu);
500 					len -= mtu;
501 				}
502 			}
503 		}
504 		/*
505 		 * Force length even, by adding a "garbage byte" if
506 		 * necessary.
507 		 */
508 		if (len & 1) {
509 			m = mprev;
510 			if (m->m_len + m->m_off < MMAXOFF)
511 				m->m_len++;
512 			else {
513 				struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA);
514 
515 				if (m1 == 0) {
516 					m_freem(m0);
517 					return (ENOBUFS);
518 				}
519 				m1->m_len = 1;
520 				m1->m_off = MMAXOFF - 1;
521 				m->m_next = m1;
522 			}
523 		}
524 		m = m_get(M_DONTWAIT, MT_HEADER);
525 		if (m == 0) {
526 			m_freem(m0);
527 			return (ENOBUFS);
528 		}
529 
530 		/*
531 		 * Fill in mbuf with extended SP header
532 		 * and addresses and length put into network format.
533 		 */
534 		m->m_off = MMAXOFF - sizeof (struct spidp);
535 		m->m_len = sizeof (struct spidp);
536 		m->m_next = m0;
537 		si = mtod(m, struct spidp *);
538 		*si = cb->s_shdr;
539 		if ((cb->s_flags & SF_PI) && (cb->s_flags & SF_HO)) {
540 			register struct sphdr *sh;
541 			if (m0->m_len < sizeof (*sh)) {
542 				if((m0 = m_pullup(m0, sizeof(*sh))) == NULL) {
543 					(void) m_free(m);
544 					m_freem(m0);
545 					return (EINVAL);
546 				}
547 				m->m_next = m0;
548 			}
549 			sh = mtod(m0, struct sphdr *);
550 			si->si_dt = sh->sp_dt;
551 			si->si_cc |= sh->sp_cc & SP_EM;
552 			m0->m_len -= sizeof (*sh);
553 			m0->m_off += sizeof (*sh);
554 			len -= sizeof (*sh);
555 		}
556 		len += sizeof(*si);
557 		if (cb->s_oobflags & SF_SOOB) {
558 			/*
559 			 * Per jqj@cornell:
560 			 * make sure OB packets convey exactly 1 byte.
561 			 * If the packet is 1 byte or larger, we
562 			 * have already guaranted there to be at least
563 			 * one garbage byte for the checksum, and
564 			 * extra bytes shouldn't hurt!
565 			 */
566 			if (len > sizeof(*si)) {
567 				si->si_cc |= SP_OB;
568 				len = (1 + sizeof(*si));
569 			}
570 		}
571 		si->si_len = htons((u_short)len);
572 		/*
573 		 * queue stuff up for output
574 		 */
575 		sbappendrecord(sb,m);
576 		cb->s_seq++;
577 	}
578 	/*
579 	 * update window
580 	 */
581 	{
582 		register struct sockbuf *sb2 = &so->so_rcv;
583 		int credit = ((sb2->sb_mbmax - sb2->sb_mbcnt) / cb->s_mtu);
584 		int alo = cb->s_ack + credit;
585 
586 		if (cb->s_alo < alo)
587 			cb->s_alo = alo;
588 	}
589 
590 	if (cb->s_oobflags & SF_SOOB) {
591 		/*
592 		 * must transmit this out of band packet
593 		 */
594 		cb->s_oobflags &= ~ SF_SOOB;
595 	} else {
596 		/*
597 		 * Decide what to transmit:
598 		 * If we have a new packet, send that
599 		 * (So long as it is in our allocation)
600 		 * If it is time to retransmit a packet,
601 		 * send that.
602 		 * Otherwise, see if it time to bang on them
603 		 * to ask for our current allocation.
604 		 */
605 		if (SSEQ_LT(cb->s_snt, cb->s_ralo))
606 			lookfor = cb->s_snt + 1;
607 		else if (cb->s_force == (1+TCPT_REXMT)) {
608 			lookfor = cb->s_rack;
609 		} else if (SSEQ_LT(cb->s_ralo, cb->s_seq)) {
610 			lookfor = 0;
611 			if (cb->s_timer[TCPT_PERSIST] == 0) {
612 				spp_setpersist(cb);
613 				/* tcp has cb->s_rxtshift = 0; here */
614 			}
615 		}
616 		m = sb->sb_mb;
617 		while (m) {
618 			si = mtod(m, struct spidp *);
619 			m = m->m_act;
620 			if (SSEQ_LT(si->si_seq, cb->s_rack)) {
621 				if ((sb->sb_flags & SB_WAIT)
622 				     || so->so_snd.sb_sel)
623 					 sowwakeup(so);
624 				sbdroprecord(sb);
625 				si = 0;
626 				continue;
627 			}
628 			if (SSEQ_LT(si->si_seq, lookfor))
629 				continue;
630 			break;
631 		}
632 		if (si && (si->si_seq != lookfor))
633 			si = 0;
634 	}
635 	cb->s_want = lookfor;
636 
637 	if (si) {
638 		/*
639 		 * must make a copy of this packet for
640 		 * idp_output to monkey with
641 		 */
642 		 m = m_copy(dtom(si), 0, (int)M_COPYALL);
643 		 if (m == NULL)
644 			return (ENOBUFS);
645 		 m0 = m;
646 		 si = mtod(m, struct spidp *);
647 	} else if (cb->s_force || cb->s_flags & SF_AK) {
648 		/*
649 		 * Must send an acknowledgement or a probe
650 		 */
651 		m = m_get(M_DONTWAIT, MT_HEADER);
652 		if (m == 0)
653 			return (ENOBUFS);
654 		/*
655 		 * Fill in mbuf with extended SP header
656 		 * and addresses and length put into network format.
657 		 */
658 		m->m_off = MMAXOFF - sizeof (struct spidp);
659 		m->m_len = sizeof (*si);
660 		m->m_next = 0;
661 		si = mtod(m, struct spidp *);
662 		*si = cb->s_shdr;
663 		si->si_seq = cb->s_snt + 1;
664 		si->si_len = htons(sizeof (*si));
665 		si->si_cc |= SP_SP;
666 		cb->s_flags &= ~SF_AK;
667 	}
668 	/*
669 	 * Stuff checksum and output datagram.
670 	 */
671 	if (si) {
672 		/*
673 		 * If we are almost out of allocation
674 		 * or one of the timers has gone off
675 		 * request an ack.
676 		 */
677 		if (SSEQ_GEQ(cb->s_seq, cb->s_ralo))
678 			si->si_cc |= SP_SA;
679 		if (cb->s_force) {
680 			si->si_cc |= SP_SA;
681 			cb->s_force = 0;
682 		}
683 		/*
684 		 * If this is a new packet (and not a system packet),
685 		 * and we are not currently timing anything,
686 		 * time this one and ask for an ack.
687 		 */
688 		if (SSEQ_LT(cb->s_snt, si->si_seq) && (!(si->si_cc & SP_SP))) {
689 			cb->s_snt = si->si_seq;
690 			if (cb->s_rtt == 0) {
691 				cb->s_rtseq = si->si_seq;
692 				cb->s_rtt = 1;
693 				si->si_cc |= SP_SA;
694 			}
695 			/*
696 			 * If the retransmit timer has not been set
697 			 * and this is a real packet
698 			 * then start the retransmit timer
699 			 */
700 			if (cb->s_timer[TCPT_REXMT] == 0) {
701 				TCPT_RANGESET(cb->s_timer[TCPT_REXMT],
702 					tcp_beta * cb->s_srtt, TCPTV_MIN,
703 					TCPTV_MAX);
704 				cb->s_rxtshift = 0;
705 			}
706 		}
707 		si->si_seq = htons(si->si_seq);
708 		si->si_alo = htons(cb->s_alo);
709 		si->si_ack = htons(cb->s_ack);
710 
711 		if (idpcksum) {
712 			si->si_sum = 0;
713 			len = ntohs(si->si_len);
714 			if (len & 1)
715 				len++;
716 			si->si_sum = ns_cksum(dtom(si), len);
717 		} else
718 			si->si_sum = 0xffff;
719 
720 		if (so->so_options & SO_DEBUG || traceallspps)
721 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
722 		spp_output_cnt++;
723 		if (so->so_options & SO_DONTROUTE)
724 			error = ns_output(m, (struct route *)0, NS_ROUTETOIF);
725 		else
726 			error = ns_output(m, &cb->s_nspcb->nsp_route, 0);
727 		if (traceallspps && sppconsdebug) {
728 			printf("spp_out: %x\n", error);
729 		}
730 		return (error);
731 	}
732 	if (so->so_options & SO_DEBUG || traceallspps)
733 		spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
734 	return (error);
735 }
736 
737 /*ARGSUSED*/
738 spp_ctloutput(req, so, level, name, value)
739 	int req;
740 	struct socket *so;
741 	int name;
742 	struct mbuf **value;
743 {
744 	register struct mbuf *m;
745 	struct nspcb *nsp = sotonspcb(so);
746 	register struct sppcb *cb;
747 	int mask, error = 0;
748 
749 	if (level != NSPROTO_SPP) {
750 		/* This will have to be changed when we do more general
751 		   stacking of protocols */
752 		return (idp_ctloutput(req, so, level, name, value));
753 	}
754 	if (nsp == NULL) {
755 		error = EINVAL;
756 		goto release;
757 	} else
758 		cb = nstosppcb(nsp);
759 
760 	switch (req) {
761 
762 	case PRCO_GETOPT:
763 		if (value == NULL)
764 			return (EINVAL);
765 		m = m_get(M_DONTWAIT, MT_DATA);
766 		if (m == NULL)
767 			return (ENOBUFS);
768 		switch (name) {
769 
770 		case SO_HEADERS_ON_INPUT:
771 			mask = SF_HI;
772 			goto get_flags;
773 
774 		case SO_HEADERS_ON_OUTPUT:
775 			mask = SF_HO;
776 		get_flags:
777 			m->m_len = sizeof(short);
778 			m->m_off = MMAXOFF - sizeof(short);
779 			*mtod(m, short *) = cb->s_flags & mask;
780 			break;
781 
782 		case SO_LAST_HEADER:
783 			m->m_len = sizeof(struct sphdr);
784 			m->m_off = MMAXOFF - sizeof(struct sphdr);
785 			*mtod(m, struct sphdr *) = cb->s_rhdr;
786 			break;
787 
788 		case SO_DEFAULT_HEADERS:
789 			m->m_len = sizeof(struct spidp);
790 			m->m_off = MMAXOFF - sizeof(struct sphdr);
791 			*mtod(m, struct sphdr *) = cb->s_shdr.si_s;
792 		}
793 		*value = m;
794 		break;
795 
796 	case PRCO_SETOPT:
797 		switch (name) {
798 			int *ok;
799 
800 		case SO_HEADERS_ON_INPUT:
801 			mask = SF_HI;
802 			goto set_head;
803 
804 		case SO_HEADERS_ON_OUTPUT:
805 			mask = SF_HO;
806 		set_head:
807 			if (value && *value) {
808 				ok = mtod(*value, int *);
809 				if (*ok)
810 					cb->s_flags |= mask;
811 				else
812 					cb->s_flags &= ~mask;
813 			} else error = EINVAL;
814 			break;
815 
816 		case SO_DEFAULT_HEADERS:
817 			{
818 				register struct sphdr *sp
819 						= mtod(*value, struct sphdr *);
820 				cb->s_dt = sp->sp_dt;
821 				cb->s_cc = sp->sp_cc & SP_EM;
822 			}
823 		}
824 		if (value && *value)
825 			m_freem(*value);
826 		break;
827 	}
828 	release:
829 		return (error);
830 }
831 
832 /*ARGSUSED*/
833 spp_usrreq(so, req, m, nam, rights)
834 	struct socket *so;
835 	int req;
836 	struct mbuf *m, *nam, *rights;
837 {
838 	struct nspcb *nsp = sotonspcb(so);
839 	register struct sppcb *cb;
840 	int s = splnet();
841 	int error = 0, ostate;
842 
843 	if (req == PRU_CONTROL)
844                 return (ns_control(so, (int)m, (caddr_t)nam,
845 			(struct ifnet *)rights));
846 	if (rights && rights->m_len) {
847 		error = EINVAL;
848 		goto release;
849 	}
850 	if (nsp == NULL) {
851 		if (req != PRU_ATTACH) {
852 			error = EINVAL;
853 			goto release;
854 		}
855 	} else
856 		cb = nstosppcb(nsp);
857 
858 	ostate = cb ? cb->s_state : 0;
859 
860 	switch (req) {
861 
862 	case PRU_ATTACH:
863 		if (nsp != NULL) {
864 			error = EISCONN;
865 			break;
866 		}
867 		error = ns_pcballoc(so, &nspcb);
868 		if (error)
869 			break;
870 		error = soreserve(so, 2048, 2048);
871 		if (error)
872 			break;
873 		nsp = sotonspcb(so);
874 		{
875 			struct mbuf *mm = m_getclr(M_DONTWAIT,MT_PCB);
876 
877 			if (mm == NULL) {
878 				error = ENOBUFS;
879 				break;
880 			}
881 			cb = mtod(mm, struct sppcb *);
882 			cb->s_state = TCPS_LISTEN;
883 			cb->s_snt = -1;
884 			cb->s_q.si_next = cb->s_q.si_prev = &cb->s_q;
885 			cb->s_nspcb = nsp;
886 			nsp->nsp_pcb = (caddr_t) cb;
887 		}
888 		break;
889 
890 	case PRU_DETACH:
891 		if (nsp == NULL) {
892 			error = ENOTCONN;
893 			break;
894 		}
895 		if (cb->s_state > TCPS_LISTEN)
896 			cb = spp_disconnect(cb);
897 		else
898 			cb = spp_close(cb);
899 		break;
900 
901 	case PRU_BIND:
902 		error = ns_pcbbind(nsp, nam);
903 		break;
904 
905 	case PRU_LISTEN:
906 		if (nsp->nsp_lport == 0)
907 			error = ns_pcbbind(nsp, (struct mbuf *)0);
908 		if (error == 0)
909 			cb->s_state = TCPS_LISTEN;
910 		break;
911 
912 	/*
913 	 * Initiate connection to peer.
914 	 * Enter SYN_SENT state, and mark socket as connecting.
915 	 * Start keep-alive timer, setup prototype header,
916 	 * Send initial system packet requesting connection.
917 	 */
918 	case PRU_CONNECT:
919 		if (nsp->nsp_lport == 0) {
920 			error = ns_pcbbind(nsp, (struct mbuf *)0);
921 			if (error)
922 				break;
923 		}
924 		error = ns_pcbconnect(nsp, nam);
925 		if (error)
926 			break;
927 		soisconnecting(so);
928 		cb->s_state = TCPS_SYN_SENT;
929 		cb->s_did = 0;
930 		spp_template(cb);
931 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
932 		cb->s_force = 1 + TCPTV_KEEP;
933 		/*
934 		 * Other party is required to respond to
935 		 * the port I send from, but he is not
936 		 * required to answer from where I am sending to,
937 		 * so allow wildcarding.
938 		 * original port I am sending to is still saved in
939 		 * cb->s_dport.
940 		 */
941 		nsp->nsp_fport = 0;
942 		error = spp_output(cb, (struct mbuf *) 0);
943 		break;
944 
945 	case PRU_CONNECT2:
946 		error = EOPNOTSUPP;
947 		break;
948 
949 	/*
950 	 * We may decide later to implement connection closing
951 	 * handshaking at the spp level optionally.
952 	 * here is the hook to do it:
953 	 */
954 	case PRU_DISCONNECT:
955 		cb = spp_disconnect(cb);
956 		break;
957 
958 	/*
959 	 * Accept a connection.  Essentially all the work is
960 	 * done at higher levels; just return the address
961 	 * of the peer, storing through addr.
962 	 */
963 	case PRU_ACCEPT: {
964 		struct sockaddr_ns *sns = mtod(nam, struct sockaddr_ns *);
965 
966 		nam->m_len = sizeof (struct sockaddr_ns);
967 		sns->sns_family = AF_NS;
968 		sns->sns_addr = nsp->nsp_faddr;
969 		break;
970 		}
971 
972 	case PRU_SHUTDOWN:
973 		socantsendmore(so);
974 		cb = spp_usrclosed(cb);
975 		if (cb)
976 			error = spp_output(cb, (struct mbuf *) 0);
977 		break;
978 
979 	/*
980 	 * After a receive, possibly send acknowledgment
981 	 * updating allocation.
982 	 */
983 	case PRU_RCVD:
984 		(void) spp_output(cb, (struct mbuf *) 0);
985 		break;
986 
987 	case PRU_SEND:
988 		error = spp_output(cb, m);
989 		m = NULL;
990 		break;
991 
992 	case PRU_ABORT:
993 		(void) spp_drop(cb, ECONNABORTED);
994 		break;
995 
996 	case PRU_SENSE:
997 	case PRU_CONTROL:
998 		m = NULL;
999 		error = EOPNOTSUPP;
1000 		break;
1001 
1002 	case PRU_RCVOOB:
1003 		if ( ! (cb->s_oobflags & SF_IOOB) ) {
1004 			error = EWOULDBLOCK;
1005 			break;
1006 		}
1007 		m->m_len = 1;
1008 		*mtod(m, caddr_t) = cb->s_iobc;
1009 		cb->s_oobflags &= ~ SF_IOOB;
1010 		break;
1011 
1012 	case PRU_SENDOOB:
1013 		if (sbspace(&so->so_snd) < -512) {
1014 			m_freem(m);
1015 			error = ENOBUFS;
1016 			break;
1017 		}
1018 		cb->s_oobflags |= SF_SOOB;
1019 		error = spp_output(cb, m);
1020 		m = NULL;
1021 		cb->s_oobflags &= ~SF_SOOB;
1022 		break;
1023 
1024 	case PRU_SOCKADDR:
1025 		ns_setsockaddr(nsp, nam);
1026 		break;
1027 
1028 	case PRU_PEERADDR:
1029 		ns_setpeeraddr(nsp, nam);
1030 		break;
1031 
1032 	case PRU_SLOWTIMO:
1033 		cb = spp_timers(cb, (int)nam);
1034 		break;
1035 
1036 	case PRU_FASTTIMO:
1037 	case PRU_PROTORCV:
1038 	case PRU_PROTOSEND:
1039 		error =  EOPNOTSUPP;
1040 		break;
1041 
1042 	default:
1043 		panic("sp_usrreq");
1044 	}
1045 	if (cb && (so->so_options & SO_DEBUG || traceallspps))
1046 		spp_trace(SA_USER, (u_char)ostate, cb, (struct spidp *)0, req);
1047 release:
1048 	if (m != NULL)
1049 		m_freem(m);
1050 	splx(s);
1051 	return (error);
1052 }
1053 
1054 spp_usrreq_sp(so, req, m, nam, rights)
1055 	struct socket *so;
1056 	int req;
1057 	struct mbuf *m, *nam, *rights;
1058 {
1059 	int error = spp_usrreq(so, req, m, nam, rights);
1060 
1061 	if (req == PRU_ATTACH && error == 0) {
1062 		struct nspcb *nsp = sotonspcb(so);
1063 		((struct sppcb *)nsp->nsp_pcb)->s_flags |=
1064 					(SF_HI | SF_HO | SF_PI);
1065 	}
1066 	return (error);
1067 }
1068 
1069 /*
1070  * Create template to be used to send spp packets on a connection.
1071  * Called after host entry created, fills
1072  * in a skeletal spp header (choosing connection id),
1073  * minimizing the amount of work necessary when the connection is used.
1074  */
1075 spp_template(cb)
1076 	struct sppcb *cb;
1077 {
1078 	register struct nspcb *nsp = cb->s_nspcb;
1079 	register struct spidp *n = &(cb->s_shdr);
1080 
1081 	cb->s_mtu = 1024;
1082 	n->si_pt = NSPROTO_SPP;
1083 	n->si_sna = nsp->nsp_laddr;
1084 	n->si_dna = nsp->nsp_faddr;
1085 	n->si_sid = htons(spp_iss);
1086 	spp_iss += SPP_ISSINCR/2;
1087 	n->si_alo = 1;
1088 }
1089 
1090 /*
1091  * Close a SPIP control block:
1092  *	discard spp control block itself
1093  *	discard ns protocol control block
1094  *	wake up any sleepers
1095  */
1096 struct sppcb *
1097 spp_close(cb)
1098 	register struct sppcb *cb;
1099 {
1100 	register struct spidp_q *s;
1101 	struct nspcb *nsp = cb->s_nspcb;
1102 	struct socket *so = nsp->nsp_socket;
1103 	register struct mbuf *m;
1104 
1105 	s = cb->s_q.si_next;
1106 	while (s != &(cb->s_q)) {
1107 		s = s->si_next;
1108 		m = dtom(s->si_prev);
1109 		remque(s->si_prev);
1110 		m_freem(m);
1111 	}
1112 	(void) m_free(dtom(cb));
1113 	nsp->nsp_pcb = 0;
1114 	soisdisconnected(so);
1115 	ns_pcbdetach(nsp);
1116 	return ((struct sppcb *)0);
1117 }
1118 /*
1119  *	Someday we may do level 3 handshaking
1120  *	to close a connection or send a xerox style error.
1121  *	For now, just close.
1122  */
1123 struct sppcb *
1124 spp_usrclosed(cb)
1125 	register struct sppcb *cb;
1126 {
1127 	return (spp_close(cb));
1128 }
1129 struct sppcb *
1130 spp_disconnect(cb)
1131 	register struct sppcb *cb;
1132 {
1133 	return (spp_close(cb));
1134 }
1135 /*
1136  * Drop connection, reporting
1137  * the specified error.
1138  */
1139 struct sppcb *
1140 spp_drop(cb, errno)
1141 	register struct sppcb *cb;
1142 	int errno;
1143 {
1144 	struct socket *so = cb->s_nspcb->nsp_socket;
1145 
1146 	/*
1147 	 * someday, in the xerox world
1148 	 * we will generate error protocol packets
1149 	 * announcing that the socket has gone away.
1150 	 */
1151 	/*if (TCPS_HAVERCVDSYN(tp->t_state)) {
1152 		tp->t_state = TCPS_CLOSED;
1153 		(void) tcp_output(tp);
1154 	}*/
1155 	so->so_error = errno;
1156 	return (spp_close(cb));
1157 }
1158 
1159 spp_abort(nsp)
1160 	struct nspcb *nsp;
1161 {
1162 
1163 	(void) spp_close((struct sppcb *)nsp->nsp_pcb);
1164 }
1165 
1166 spp_setpersist(cb)
1167 	register struct sppcb *cb;
1168 {
1169 
1170 	/*if (cb->s_timer[TCPT_REXMT])
1171 		panic("spp_output REXMT");*/
1172 	/*
1173 	 * Start/restart persistance timer.
1174 	 */
1175 	TCPT_RANGESET(cb->s_timer[TCPT_PERSIST],
1176 	    ((int)(tcp_beta * cb->s_srtt)) << cb->s_rxtshift,
1177 	    TCPTV_PERSMIN, TCPTV_MAX);
1178 	cb->s_rxtshift++;
1179 	if (cb->s_rxtshift >= TCP_MAXRXTSHIFT)
1180 		cb->s_rxtshift = 0;
1181 }
1182 /*
1183  * Fast timeout routine for processing delayed acks
1184  */
1185 int spp_ftcnt;
1186 spp_fasttimo()
1187 {
1188 	register struct nspcb *nsp;
1189 	register struct sppcb *cb;
1190 	int s = splnet();
1191 
1192 	nsp = nspcb.nsp_next;
1193 	spp_ftcnt++;
1194 	if (nsp)
1195 	for (; nsp != &nspcb; nsp = nsp->nsp_next)
1196 		if ((cb = (struct sppcb *)nsp->nsp_pcb) &&
1197 		    (cb->s_flags & SF_DELACK)) {
1198 			cb->s_flags &= ~SF_DELACK;
1199 			cb->s_flags |= SF_AK;
1200 			(void) spp_output(cb, (struct mbuf *) 0);
1201 		}
1202 	splx(s);
1203 }
1204 
1205 /*
1206  * spp protocol timeout routine called every 500 ms.
1207  * Updates the timers in all active pcb's and
1208  * causes finite state machine actions if timers expire.
1209  */
1210 spp_slowtimo()
1211 {
1212 	register struct nspcb *ip, *ipnxt;
1213 	register struct sppcb *cb;
1214 	int s = splnet();
1215 	register int i;
1216 
1217 	/*
1218 	 * Search through tcb's and update active timers.
1219 	 */
1220 	ip = nspcb.nsp_next;
1221 	if (ip == 0) {
1222 		splx(s);
1223 		return;
1224 	}
1225 	while (ip != &nspcb) {
1226 		cb = nstosppcb(ip);
1227 		ipnxt = ip->nsp_next;
1228 		if (cb == 0)
1229 			goto tpgone;
1230 		for (i = 0; i < TCPT_NTIMERS; i++) {
1231 			if (cb->s_timer[i] && --cb->s_timer[i] == 0) {
1232 				(void) spp_usrreq(cb->s_nspcb->nsp_socket,
1233 				    PRU_SLOWTIMO, (struct mbuf *)0,
1234 				    (struct mbuf *)i, (struct mbuf *)0);
1235 				if (ipnxt->nsp_prev != ip)
1236 					goto tpgone;
1237 			}
1238 		}
1239 		cb->s_idle++;
1240 		if (cb->s_rtt)
1241 			cb->s_rtt++;
1242 tpgone:
1243 		ip = ipnxt;
1244 	}
1245 	spp_iss += SPP_ISSINCR/PR_SLOWHZ;		/* increment iss */
1246 	splx(s);
1247 }
1248 
1249 float	spp_backoff[TCP_MAXRXTSHIFT] =
1250     { 1.0, 1.2, 1.4, 1.7, 2.0, 3.0, 5.0, 8.0, 16.0, 32.0 };
1251 extern int tcpexprexmtbackoff;
1252 /*
1253  * TCP timer processing.
1254  */
1255 struct sppcb *
1256 spp_timers(cb, timer)
1257 	register struct sppcb *cb;
1258 	int timer;
1259 {
1260 
1261 	cb->s_force = 1 + timer;
1262 	switch (timer) {
1263 
1264 	/*
1265 	 * 2 MSL timeout in shutdown went off.  Delete connection
1266 	 * control block.
1267 	 */
1268 	case TCPT_2MSL:
1269 		cb = spp_close(cb);
1270 		break;
1271 
1272 	/*
1273 	 * Retransmission timer went off.  Message has not
1274 	 * been acked within retransmit interval.  Back off
1275 	 * to a longer retransmit interval and retransmit all
1276 	 * unacknowledged messages in the window.
1277 	 */
1278 	case TCPT_REXMT:
1279 		cb->s_rxtshift++;
1280 		if (cb->s_rxtshift > TCP_MAXRXTSHIFT) {
1281 			cb = spp_drop(cb, ETIMEDOUT);
1282 			break;
1283 		}
1284 		(void) spp_output(cb, (struct mbuf *) 0);
1285 		TCPT_RANGESET(cb->s_timer[TCPT_REXMT],
1286 		    (int)cb->s_srtt, TCPTV_MIN, TCPTV_MAX);
1287 		if (tcpexprexmtbackoff) {
1288 			TCPT_RANGESET(cb->s_timer[TCPT_REXMT],
1289 			    cb->s_timer[TCPT_REXMT] << cb->s_rxtshift,
1290 			    TCPTV_MIN, TCPTV_MAX);
1291 		} else {
1292 			TCPT_RANGESET(cb->s_timer[TCPT_REXMT],
1293 			    cb->s_timer[TCPT_REXMT] *
1294 			        spp_backoff[cb->s_rxtshift - 1],
1295 			    TCPTV_MIN, TCPTV_MAX);
1296 		}
1297 		break;
1298 
1299 	/*
1300 	 * Persistance timer into zero window.
1301 	 * Force a probe to be sent.
1302 	 */
1303 	case TCPT_PERSIST:
1304 		(void) spp_output(cb, (struct mbuf *) 0);
1305 		spp_setpersist(cb);
1306 		break;
1307 
1308 	/*
1309 	 * Keep-alive timer went off; send something
1310 	 * or drop connection if idle for too long.
1311 	 */
1312 	case TCPT_KEEP:
1313 		if (cb->s_state < TCPS_ESTABLISHED)
1314 			goto dropit;
1315 		if (cb->s_nspcb->nsp_socket->so_options & SO_KEEPALIVE) {
1316 		    	if (cb->s_idle >= TCPTV_MAXIDLE)
1317 				goto dropit;
1318 			(void) spp_output(cb, (struct mbuf *) 0);
1319 		} else
1320 			cb->s_idle = 0;
1321 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
1322 		break;
1323 	dropit:
1324 		cb = spp_drop(cb, ETIMEDOUT);
1325 		break;
1326 	}
1327 	return (cb);
1328 }
1329