xref: /csrg-svn/sys/netns/spp_usrreq.c (revision 24615)
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	6.11 (Berkeley) 09/07/85
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 int spp_hardnosed;
45 
46 /*ARGSUSED*/
47 spp_input(m, nsp, ifp)
48 	register struct mbuf *m;
49 	register struct nspcb *nsp;
50 	struct ifnet *ifp;
51 {
52 	register struct sppcb *cb;
53 	register struct spidp *si = mtod(m, struct spidp *);
54 	register struct socket *so;
55 	short ostate;
56 	int dropsocket = 0;
57 
58 
59 	if (nsp == 0) {
60 		panic("No nspcb in spp_input\n");
61 		return;
62 	}
63 
64 	cb = nstosppcb(nsp);
65 	if (cb == 0) goto bad;
66 
67 	if (m->m_len < sizeof(*si)) {
68 		if ((m = m_pullup(m, sizeof(*si))) == 0) {
69 			spp_istat.hdrops++;
70 			return;
71 		}
72 		si = mtod(m, struct spidp *);
73 	}
74 	si->si_seq = ntohs(si->si_seq);
75 	si->si_ack = ntohs(si->si_ack);
76 	si->si_alo = ntohs(si->si_alo);
77 
78 	so = nsp->nsp_socket;
79 	if (so->so_options & SO_DEBUG || traceallspps) {
80 		ostate = cb->s_state;
81 		spp_savesi = *si;
82 	}
83 	if (so->so_options & SO_ACCEPTCONN) {
84 		so = sonewconn(so);
85 		if (so == 0) {
86 			spp_istat.nonucn++;
87 			goto drop;
88 		}
89 		/*
90 		 * This is ugly, but ....
91 		 *
92 		 * Mark socket as temporary until we're
93 		 * committed to keeping it.  The code at
94 		 * ``drop'' and ``dropwithreset'' check the
95 		 * flag dropsocket to see if the temporary
96 		 * socket created here should be discarded.
97 		 * We mark the socket as discardable until
98 		 * we're committed to it below in TCPS_LISTEN.
99 		 */
100 		dropsocket++;
101 		nsp = (struct nspcb *)so->so_pcb;
102 		nsp->nsp_laddr = si->si_dna;
103 		cb = nstosppcb(nsp);
104 		cb->s_state = TCPS_LISTEN;
105 	}
106 
107 	/*
108 	 * Packet received on connection.
109 	 * reset idle time and keep-alive timer;
110 	 */
111 	cb->s_idle = 0;
112 	cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
113 
114 	switch (cb->s_state) {
115 
116 	case TCPS_LISTEN:{
117 		struct mbuf *am;
118 		register struct sockaddr_ns *sns;
119 		struct ns_addr laddr;
120 
121 		/*
122 		 * If somebody here was carying on a conversation
123 		 * and went away, and his pen pal thinks he can
124 		 * still talk, we get the misdirected packet.
125 		 */
126 		if (spp_hardnosed && (si->si_did != 0 || si->si_seq != 0)) {
127 			spp_istat.gonawy++;
128 			goto dropwithreset;
129 		}
130 		am = m_get(M_DONTWAIT, MT_SONAME);
131 		if (am == NULL)
132 			goto drop;
133 		am->m_len = sizeof (struct sockaddr_ns);
134 		sns = mtod(am, struct sockaddr_ns *);
135 		sns->sns_family = AF_NS;
136 		sns->sns_addr = si->si_sna;
137 		laddr = nsp->nsp_laddr;
138 		if (ns_nullhost(laddr))
139 			nsp->nsp_laddr = si->si_dna;
140 		if (ns_pcbconnect(nsp, am)) {
141 			nsp->nsp_laddr = laddr;
142 			(void) m_free(am);
143 			spp_istat.noconn++;
144 			goto drop;
145 		}
146 		(void) m_free(am);
147 		cb->s_state = TCPS_SYN_RECEIVED;
148 		spp_template(cb);
149 		cb->s_did = si->si_sid;
150 		cb->s_rack = si->si_ack;
151 		cb->s_ralo = si->si_alo;
152 		cb->s_flags |= SF_AK;
153 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
154 		dropsocket = 0;		/* committed to socket */
155 		}
156 		break;
157 
158 	/*
159 	 * This state means that we have gotten a response
160 	 * to our attempt to establish a connection.
161 	 * We fill in the data from the other side,
162 	 * telling us which port to respond to, instead of the well-
163 	 * known one we might have sent to in the first place.
164 	 * We also require that this is a response to our
165 	 * connection id.
166 	 */
167 	case TCPS_SYN_SENT:
168 		if (si->si_did!=cb->s_sid) {
169 			spp_istat.notme++;
170 			goto drop;
171 		}
172 		cb->s_did = si->si_sid;
173 		cb->s_rack = si->si_ack;
174 		cb->s_ralo = si->si_alo;
175 		cb->s_dport = nsp->nsp_fport =  si->si_sport;
176 		cb->s_timer[TCPT_REXMT] = 0;
177 		cb->s_flags |= SF_AK;
178 		soisconnected(so);
179 		cb->s_state = TCPS_ESTABLISHED;
180 		break;
181 	/*
182 	 * This state means that we have heard a response
183 	 * to our acceptance of their connection
184 	 * It is probably logically unnecessary in this
185 	 * implementation.
186 	 */
187 	 case TCPS_SYN_RECEIVED:
188 		if (si->si_did!=cb->s_sid) {
189 			spp_istat.wrncon++;
190 			goto drop;
191 		}
192 		nsp->nsp_fport =  si->si_sport;
193 		cb->s_timer[TCPT_REXMT] = 0;
194 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
195 		soisconnected(so);
196 		cb->s_state = TCPS_ESTABLISHED;
197 	}
198 	if (so->so_options & SO_DEBUG || traceallspps)
199 		spp_trace(SA_INPUT, (u_char)ostate, cb, &spp_savesi, 0);
200 
201 	m->m_len -= sizeof (struct idp);
202 	m->m_off += sizeof (struct idp);
203 
204 	if (spp_reass(cb,si)) {
205 		goto drop;
206 	}
207 	(void) spp_output(cb,(struct mbuf *)0);
208 	return;
209 
210 dropwithreset:
211 	if (dropsocket)
212 		(void) soabort(so);
213 	si->si_seq = ntohs(si->si_seq);
214 	si->si_ack = ntohs(si->si_ack);
215 	si->si_alo = ntohs(si->si_alo);
216 	ns_error(dtom(si), NS_ERR_NOSOCK, 0);
217 	if (cb->s_nspcb->nsp_socket->so_options & SO_DEBUG || traceallspps)
218 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
219 	return;
220 
221 drop:
222 bad:
223 	if (cb == 0 || cb->s_nspcb->nsp_socket->so_options & SO_DEBUG || traceallspps)
224 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
225 	m_freem(m);
226 }
227 
228 /*
229  * This is structurally similar to the tcp reassembly routine
230  * but its function is somewhat different:  It merely queues
231  * packets up, and suppresses duplicates.
232  */
233 spp_reass(cb,si)
234 register struct sppcb *cb;
235 register struct spidp *si;
236 {
237 	register struct spidp_q *q;
238 	register struct mbuf *m;
239 	struct socket *so = cb->s_nspcb->nsp_socket;
240 	struct sockbuf *sb = & (so->so_rcv);
241 	char packetp = cb->s_flags & SF_HI;
242 	char wakeup = 0;
243 
244 
245 	if (si == SI(0))
246 		goto present;
247 	/*
248 	 * Update our news from them.
249 	 */
250 	if (si->si_cc & SP_SA)
251 		cb->s_flags |= SF_DELACK;
252 	if (SSEQ_GT(si->si_ack,cb->s_rack)) {
253 		cb->s_rack = si->si_ack;
254 		cb->s_timer[TCPT_REXMT] = 0;
255 
256 		/*
257 		 * If transmit timer is running and timed sequence
258 		 * number was acked, update smoothed round trip time.
259 		 */
260 		if (cb->s_rtt && SSEQ_GT(si->si_ack, cb->s_rtseq)) {
261 			if (cb->s_srtt == 0)
262 				cb->s_srtt = cb->s_rtt;
263 			else
264 				cb->s_srtt =
265 				    tcp_alpha * cb->s_srtt +
266 				    (1 - tcp_alpha) * cb->s_rtt;
267 			cb->s_rtt = 0;
268 		}
269 	}
270 	if (SSEQ_GT(si->si_alo,cb->s_ralo)) {
271 		cb->s_ralo = si->si_alo;
272 		cb->s_timer[TCPT_PERSIST] = 0;
273 	}
274 	/*
275 	 * If this is a system packet, we don't need to
276 	 * queue it up, and won't update acknowledge #
277 	 */
278 	if (si->si_cc & SP_SP) {
279 		m_freem(dtom(si));
280 		return (0);
281 	}
282 
283 	/*
284 	 * If this packet number has a sequence number less
285 	 * than that of the first packet not yet seen coming
286 	 * from them, this must be a duplicate, so drop.
287 	 */
288 	if (SSEQ_LT(si->si_seq,cb->s_ack)) {
289 		spp_istat.bdreas++;
290 		if (si->si_seq == cb->s_ack-1)
291 			spp_istat.lstdup++;
292 		return (1);
293 	}
294 	/*
295 	 * If this packet number is higher than that which
296 	 * we have allocated refuse it, unless urgent
297 	 */
298 	if (SSEQ_GT(si->si_seq,cb->s_alo) && (!(si->si_cc & SP_OB))) {
299 		spp_istat.notyet++;
300 		return (1);
301 	}
302 	/*
303 	 * If this packet is urgent, inform process
304 	 */
305 	if (si->si_cc & SP_OB) {
306 		cb->s_iobc = ((char *)si)[1 + sizeof(*si)];
307 		sohasoutofband(so);
308 	}
309 
310 	/*
311 	 * Loop through all packets queued up to insert in
312 	 * appropriate sequence.
313 	 */
314 
315 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
316 	    if (si->si_seq == SI(q)->si_seq) return (1); /*duplicate */
317 	    if (SSEQ_LT(si->si_seq,SI(q)->si_seq)) break;
318 	}
319 	insque(si,q->si_prev);
320 
321 present:
322 #define SPINC sizeof(struct sphdr)
323 	/*
324 	 * Loop through all packets queued up to update acknowledge
325 	 * number, and present all acknowledged data to user;
326 	 * If in packet interface mode, show packet headers.
327 	 */
328 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
329 		  if (SI(q)->si_seq == cb->s_ack) {
330 			cb->s_ack++;
331 			m = dtom(q);
332 			if (SI(q)->si_cc & SP_OB) {
333 				if (sb->sb_cc)
334 					so->so_oobmark = sb->sb_cc;
335 				else
336 					so->so_state |= SS_RCVATMARK;
337 			}
338 			q = q->si_prev;
339 			remque(q->si_next);
340 			wakeup = 1;
341 			if (packetp) {
342 				sbappendrecord(sb,m);
343 			} else {
344 				cb->s_rhdr = *mtod(m, struct sphdr *);
345 				m->m_off += SPINC;
346 				m->m_len -= SPINC;
347 				sbappend(sb,m);
348 			}
349 		  } else
350 			break;
351 	}
352 	if (wakeup) sorwakeup(so);
353 	return (0);
354 }
355 
356 spp_ctlinput(cmd, arg)
357 	int cmd;
358 	caddr_t arg;
359 {
360 	struct ns_addr *na;
361 	extern u_char nsctlerrmap[];
362 	extern spp_abort();
363 	extern struct nspcb *idp_drop();
364 	struct ns_errp *errp;
365 	struct nspcb *nsp;
366 	struct sockaddr_ns *sns;
367 	int type;
368 
369 	if (cmd < 0 || cmd > PRC_NCMDS)
370 		return;
371 	type = NS_ERR_UNREACH_HOST;
372 
373 	switch (cmd) {
374 
375 	case PRC_ROUTEDEAD:
376 	case PRC_QUENCH:
377 		break;
378 
379 	case PRC_IFDOWN:
380 	case PRC_HOSTDEAD:
381 	case PRC_HOSTUNREACH:
382 		sns = (struct sockaddr_ns *)arg;
383 		if (sns->sns_family != AF_NS)
384 			return;
385 		na = &sns->sns_addr;
386 		break;
387 
388 	default:
389 		errp = (struct ns_errp *)arg;
390 		na = &errp->ns_err_idp.idp_dna;
391 		type = errp->ns_err_num;
392 		type = ntohs((u_short)type);
393 	}
394 	switch (type) {
395 
396 	case NS_ERR_UNREACH_HOST:
397 		ns_pcbnotify(na, (int)nsctlerrmap[cmd], spp_abort, (long) 0);
398 		break;
399 
400 	case NS_ERR_TOO_BIG:
401 	case NS_ERR_NOSOCK:
402 		nsp = ns_pcblookup(na, errp->ns_err_idp.idp_sna.x_port,
403 			NS_WILDCARD);
404 		if (nsp) {
405 			if(nsp->nsp_pcb)
406 				(void) spp_drop((struct sppcb *)nsp->nsp_pcb,
407 						(int)nsctlerrmap[cmd]);
408 			else
409 				(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
410 		}
411 	}
412 }
413 
414 #ifdef notdef
415 int
416 spp_fixmtu(nsp)
417 register struct nspcb *nsp;
418 {
419 	register struct sppcb *cb = (struct sppcb *)(nsp->nsp_pcb);
420 	register struct mbuf *m;
421 	register struct spidp *si;
422 	struct ns_errp *ep;
423 	struct sockbuf *sb;
424 	int badseq, len;
425 	struct mbuf *firstbad, *m0;
426 
427 	if (cb) {
428 		/*
429 		 * The notification that we have sent
430 		 * too much is bad news -- we will
431 		 * have to go through queued up so far
432 		 * splitting ones which are too big and
433 		 * reassigning sequence numbers and checksums.
434 		 * we should then retransmit all packets from
435 		 * one above the offending packet to the last one
436 		 * we had sent (or our allocation)
437 		 * then the offending one so that the any queued
438 		 * data at our destination will be discarded.
439 		 */
440 		 ep = (struct ns_errp *)nsp->nsp_notify_param;
441 		 sb = &nsp->nsp_socket->so_snd;
442 		 cb->s_mtu = ep->ns_err_param;
443 		 badseq = SI(&ep->ns_err_idp)->si_seq;
444 		 for (m = sb->sb_mb; m; m = m->m_act) {
445 			si = mtod(m, struct spidp *);
446 			if (si->si_seq == badseq)
447 				break;
448 		 }
449 		 if (m == 0) return;
450 		 firstbad = m;
451 		 /*for (;;) {*/
452 			/* calculate length */
453 			for (m0 = m, len = 0; m ; m = m->m_next)
454 				len += m->m_len;
455 			if (len > cb->s_mtu) {
456 			}
457 		/* FINISH THIS
458 		} */
459 	}
460 }
461 #endif
462 
463 int spp_output_cnt = 0;
464 
465 spp_output(cb, m0)
466 	register struct sppcb *cb;
467 	struct mbuf *m0;
468 {
469 	struct socket *so = cb->s_nspcb->nsp_socket;
470 	register struct mbuf *m;
471 	register struct spidp *si = (struct spidp *) 0;
472 	register struct sockbuf *sb = &(so->so_snd);
473 	register int len = 0;
474 	int error = 0;
475 	u_short lookfor = 0;
476 	struct mbuf *mprev;
477 	extern int idpcksum;
478 
479 	if (m0) {
480 		int mtu = cb->s_mtu;
481 		int datalen;
482 		/*
483 		 * Make sure that packet isn't too big.
484 		 */
485 		for (m = m0; m ; m = m->m_next) {
486 			mprev = m;
487 			len += m->m_len;
488 		}
489 		datalen = (cb->s_flags & SF_HO) ?
490 				len - sizeof (struct sphdr) : len;
491 		if (datalen > mtu) {
492 			if (cb->s_flags & SF_PI) {
493 				m_freem(m0);
494 				return (EMSGSIZE);
495 			} else {
496 				int off = 0;
497 				int oldEM = cb->s_cc & SP_EM;
498 
499 				cb->s_cc &= ~SP_EM;
500 				while (len > mtu) {
501 					m = m_copy(m0, off, mtu);
502 					if (m == NULL) {
503 						error = ENOBUFS;
504 						goto bad_copy;
505 					}
506 					error = spp_output(cb, m);
507 					if (error) {
508 					bad_copy:
509 						cb->s_cc |= oldEM;
510 						m_freem(m0);
511 						return(error);
512 					}
513 					m_adj(m0, mtu);
514 					len -= mtu;
515 				}
516 				cb->s_cc |= oldEM;
517 			}
518 		}
519 		/*
520 		 * Force length even, by adding a "garbage byte" if
521 		 * necessary.
522 		 */
523 		if (len & 1) {
524 			m = mprev;
525 			if (m->m_len + m->m_off < MMAXOFF)
526 				m->m_len++;
527 			else {
528 				struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA);
529 
530 				if (m1 == 0) {
531 					m_freem(m0);
532 					return (ENOBUFS);
533 				}
534 				m1->m_len = 1;
535 				m1->m_off = MMAXOFF - 1;
536 				m->m_next = m1;
537 			}
538 		}
539 		m = m_get(M_DONTWAIT, MT_HEADER);
540 		if (m == 0) {
541 			m_freem(m0);
542 			return (ENOBUFS);
543 		}
544 		/*
545 		 * Fill in mbuf with extended SP header
546 		 * and addresses and length put into network format.
547 		 */
548 		m->m_off = MMAXOFF - sizeof (struct spidp);
549 		m->m_len = sizeof (struct spidp);
550 		m->m_next = m0;
551 		si = mtod(m, struct spidp *);
552 		*si = cb->s_shdr;
553 		if ((cb->s_flags & SF_PI) && (cb->s_flags & SF_HO)) {
554 			register struct sphdr *sh;
555 			if (m0->m_len < sizeof (*sh)) {
556 				if((m0 = m_pullup(m0, sizeof(*sh))) == NULL) {
557 					(void) m_free(m);
558 					m_freem(m0);
559 					return (EINVAL);
560 				}
561 				m->m_next = m0;
562 			}
563 			sh = mtod(m0, struct sphdr *);
564 			si->si_dt = sh->sp_dt;
565 			si->si_cc |= sh->sp_cc & SP_EM;
566 			m0->m_len -= sizeof (*sh);
567 			m0->m_off += sizeof (*sh);
568 			len -= sizeof (*sh);
569 		}
570 		len += sizeof(*si);
571 		if (cb->s_oobflags & SF_SOOB) {
572 			/*
573 			 * Per jqj@cornell:
574 			 * make sure OB packets convey exactly 1 byte.
575 			 * If the packet is 1 byte or larger, we
576 			 * have already guaranted there to be at least
577 			 * one garbage byte for the checksum, and
578 			 * extra bytes shouldn't hurt!
579 			 */
580 			if (len > sizeof(*si)) {
581 				si->si_cc |= SP_OB;
582 				len = (1 + sizeof(*si));
583 			}
584 		}
585 		si->si_len = htons((u_short)len);
586 		/*
587 		 * queue stuff up for output
588 		 */
589 		sbappendrecord(sb,m);
590 		cb->s_seq++;
591 	}
592 	/*
593 	 * update window
594 	 */
595 	{
596 		register struct sockbuf *sb2 = &so->so_rcv;
597 		int credit = ((sb2->sb_mbmax - sb2->sb_mbcnt) / cb->s_mtu);
598 		int alo = cb->s_ack + credit;
599 
600 		if (cb->s_alo < alo)
601 			cb->s_alo = alo;
602 	}
603 
604 	if (cb->s_oobflags & SF_SOOB) {
605 		/*
606 		 * must transmit this out of band packet
607 		 */
608 		cb->s_oobflags &= ~ SF_SOOB;
609 	} else {
610 		/*
611 		 * Decide what to transmit:
612 		 * If we have a new packet, send that
613 		 * (So long as it is in our allocation)
614 		 * If it is time to retransmit a packet,
615 		 * send that.
616 		 * Otherwise, see if it time to bang on them
617 		 * to ask for our current allocation.
618 		 */
619 		if (SSEQ_LT(cb->s_snt, cb->s_ralo))
620 			lookfor = cb->s_snt + 1;
621 		else if (cb->s_force == (1+TCPT_REXMT)) {
622 			lookfor = cb->s_rack;
623 		} else if (SSEQ_LT(cb->s_ralo, cb->s_seq)) {
624 			lookfor = 0;
625 			if (cb->s_timer[TCPT_PERSIST] == 0) {
626 				spp_setpersist(cb);
627 				/* tcp has cb->s_rxtshift = 0; here */
628 			}
629 		}
630 		m = sb->sb_mb;
631 		while (m) {
632 			si = mtod(m, struct spidp *);
633 			m = m->m_act;
634 			if (SSEQ_LT(si->si_seq, cb->s_rack)) {
635 				if ((sb->sb_flags & SB_WAIT)
636 				     || so->so_snd.sb_sel)
637 					 sowwakeup(so);
638 				sbdroprecord(sb);
639 				si = 0;
640 				continue;
641 			}
642 			if (SSEQ_LT(si->si_seq, lookfor))
643 				continue;
644 			break;
645 		}
646 		if (si && (si->si_seq != lookfor))
647 			si = 0;
648 	}
649 	cb->s_want = lookfor;
650 
651 	if (si) {
652 		/*
653 		 * must make a copy of this packet for
654 		 * idp_output to monkey with
655 		 */
656 		 m = m_copy(dtom(si), 0, (int)M_COPYALL);
657 		 if (m == NULL)
658 			return (ENOBUFS);
659 		 m0 = m;
660 		 si = mtod(m, struct spidp *);
661 	} else if (cb->s_force || cb->s_flags & SF_AK) {
662 		/*
663 		 * Must send an acknowledgement or a probe
664 		 */
665 		m = m_get(M_DONTWAIT, MT_HEADER);
666 		if (m == 0)
667 			return (ENOBUFS);
668 		/*
669 		 * Fill in mbuf with extended SP header
670 		 * and addresses and length put into network format.
671 		 */
672 		m->m_off = MMAXOFF - sizeof (struct spidp);
673 		m->m_len = sizeof (*si);
674 		m->m_next = 0;
675 		si = mtod(m, struct spidp *);
676 		*si = cb->s_shdr;
677 		si->si_seq = cb->s_snt + 1;
678 		si->si_len = htons(sizeof (*si));
679 		si->si_cc |= SP_SP;
680 		cb->s_flags &= ~SF_AK;
681 	}
682 	/*
683 	 * Stuff checksum and output datagram.
684 	 */
685 	if (si) {
686 		/*
687 		 * If we are almost out of allocation
688 		 * or one of the timers has gone off
689 		 * request an ack.
690 		 */
691 		if (SSEQ_GEQ(cb->s_seq, cb->s_ralo))
692 			si->si_cc |= SP_SA;
693 		if (cb->s_force) {
694 			si->si_cc |= SP_SA;
695 			cb->s_force = 0;
696 		}
697 		/*
698 		 * If this is a new packet (and not a system packet),
699 		 * and we are not currently timing anything,
700 		 * time this one and ask for an ack.
701 		 */
702 		if (SSEQ_LT(cb->s_snt, si->si_seq) && (!(si->si_cc & SP_SP))) {
703 			cb->s_snt = si->si_seq;
704 			if (cb->s_rtt == 0) {
705 				cb->s_rtseq = si->si_seq;
706 				cb->s_rtt = 1;
707 				si->si_cc |= SP_SA;
708 			}
709 			/*
710 			 * If the retransmit timer has not been set
711 			 * and this is a real packet
712 			 * then start the retransmit timer
713 			 */
714 			if (cb->s_timer[TCPT_REXMT] == 0) {
715 				TCPT_RANGESET(cb->s_timer[TCPT_REXMT],
716 					tcp_beta * cb->s_srtt, TCPTV_MIN,
717 					TCPTV_MAX);
718 				cb->s_rxtshift = 0;
719 			}
720 		}
721 		si->si_seq = htons(si->si_seq);
722 		si->si_alo = htons(cb->s_alo);
723 		si->si_ack = htons(cb->s_ack);
724 
725 		if (idpcksum) {
726 			si->si_sum = 0;
727 			len = ntohs(si->si_len);
728 			if (len & 1)
729 				len++;
730 			si->si_sum = ns_cksum(dtom(si), len);
731 		} else
732 			si->si_sum = 0xffff;
733 
734 		if (so->so_options & SO_DEBUG || traceallspps)
735 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
736 		spp_output_cnt++;
737 		if (so->so_options & SO_DONTROUTE)
738 			error = ns_output(m, (struct route *)0, NS_ROUTETOIF);
739 		else
740 			error = ns_output(m, &cb->s_nspcb->nsp_route, 0);
741 		if (traceallspps && sppconsdebug) {
742 			printf("spp_out: %x\n", error);
743 		}
744 		return (error);
745 	}
746 	if (so->so_options & SO_DEBUG || traceallspps)
747 		spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
748 	return (error);
749 }
750 
751 /*ARGSUSED*/
752 spp_ctloutput(req, so, level, name, value)
753 	int req;
754 	struct socket *so;
755 	int name;
756 	struct mbuf **value;
757 {
758 	register struct mbuf *m;
759 	struct nspcb *nsp = sotonspcb(so);
760 	register struct sppcb *cb;
761 	int mask, error = 0;
762 
763 	if (level != NSPROTO_SPP) {
764 		/* This will have to be changed when we do more general
765 		   stacking of protocols */
766 		return (idp_ctloutput(req, so, level, name, value));
767 	}
768 	if (nsp == NULL) {
769 		error = EINVAL;
770 		goto release;
771 	} else
772 		cb = nstosppcb(nsp);
773 
774 	switch (req) {
775 
776 	case PRCO_GETOPT:
777 		if (value == NULL)
778 			return (EINVAL);
779 		m = m_get(M_DONTWAIT, MT_DATA);
780 		if (m == NULL)
781 			return (ENOBUFS);
782 		switch (name) {
783 
784 		case SO_HEADERS_ON_INPUT:
785 			mask = SF_HI;
786 			goto get_flags;
787 
788 		case SO_HEADERS_ON_OUTPUT:
789 			mask = SF_HO;
790 		get_flags:
791 			m->m_len = sizeof(short);
792 			m->m_off = MMAXOFF - sizeof(short);
793 			*mtod(m, short *) = cb->s_flags & mask;
794 			break;
795 
796 		case SO_MTU:
797 			m->m_len = sizeof(u_short);
798 			m->m_off = MMAXOFF - sizeof(short);
799 			*mtod(m, short *) = cb->s_mtu;
800 			break;
801 
802 		case SO_LAST_HEADER:
803 			m->m_len = sizeof(struct sphdr);
804 			m->m_off = MMAXOFF - sizeof(struct sphdr);
805 			*mtod(m, struct sphdr *) = cb->s_rhdr;
806 			break;
807 
808 		case SO_DEFAULT_HEADERS:
809 			m->m_len = sizeof(struct spidp);
810 			m->m_off = MMAXOFF - sizeof(struct sphdr);
811 			*mtod(m, struct sphdr *) = cb->s_shdr.si_s;
812 		}
813 		*value = m;
814 		break;
815 
816 	case PRCO_SETOPT:
817 		if (value == 0 || *value == 0) {
818 			error = EINVAL;
819 			break;
820 		}
821 		switch (name) {
822 			int *ok;
823 
824 		case SO_HEADERS_ON_INPUT:
825 			mask = SF_HI;
826 			goto set_head;
827 
828 		case SO_HEADERS_ON_OUTPUT:
829 			mask = SF_HO;
830 		set_head:
831 			if (cb->s_flags & SF_PI) {
832 				ok = mtod(*value, int *);
833 				if (*ok)
834 					cb->s_flags |= mask;
835 				else
836 					cb->s_flags &= ~mask;
837 			} else error = EINVAL;
838 			break;
839 
840 		case SO_MTU:
841 			cb->s_mtu = *(mtod(*value, u_short *));
842 			break;
843 
844 		case SO_DEFAULT_HEADERS:
845 			{
846 				register struct sphdr *sp
847 						= mtod(*value, struct sphdr *);
848 				cb->s_dt = sp->sp_dt;
849 				cb->s_cc = sp->sp_cc & SP_EM;
850 			}
851 		}
852 		m_freem(*value);
853 		break;
854 	}
855 	release:
856 		return (error);
857 }
858 
859 /*ARGSUSED*/
860 spp_usrreq(so, req, m, nam, rights)
861 	struct socket *so;
862 	int req;
863 	struct mbuf *m, *nam, *rights;
864 {
865 	struct nspcb *nsp = sotonspcb(so);
866 	register struct sppcb *cb;
867 	int s = splnet();
868 	int error = 0, ostate;
869 
870 	if (req == PRU_CONTROL)
871                 return (ns_control(so, (int)m, (caddr_t)nam,
872 			(struct ifnet *)rights));
873 	if (rights && rights->m_len) {
874 		error = EINVAL;
875 		goto release;
876 	}
877 	if (nsp == NULL) {
878 		if (req != PRU_ATTACH) {
879 			error = EINVAL;
880 			goto release;
881 		}
882 	} else
883 		cb = nstosppcb(nsp);
884 
885 	ostate = cb ? cb->s_state : 0;
886 
887 	switch (req) {
888 
889 	case PRU_ATTACH:
890 		if (nsp != NULL) {
891 			error = EISCONN;
892 			break;
893 		}
894 		error = ns_pcballoc(so, &nspcb);
895 		if (error)
896 			break;
897 		error = soreserve(so, 2048, 2048);
898 		if (error)
899 			break;
900 		nsp = sotonspcb(so);
901 		{
902 			struct mbuf *mm = m_getclr(M_DONTWAIT,MT_PCB);
903 
904 			if (mm == NULL) {
905 				error = ENOBUFS;
906 				break;
907 			}
908 			cb = mtod(mm, struct sppcb *);
909 			cb->s_state = TCPS_LISTEN;
910 			cb->s_snt = -1;
911 			cb->s_q.si_next = cb->s_q.si_prev = &cb->s_q;
912 			cb->s_nspcb = nsp;
913 			nsp->nsp_pcb = (caddr_t) cb;
914 		}
915 		break;
916 
917 	case PRU_DETACH:
918 		if (nsp == NULL) {
919 			error = ENOTCONN;
920 			break;
921 		}
922 		if (cb->s_state > TCPS_LISTEN)
923 			cb = spp_disconnect(cb);
924 		else
925 			cb = spp_close(cb);
926 		break;
927 
928 	case PRU_BIND:
929 		error = ns_pcbbind(nsp, nam);
930 		break;
931 
932 	case PRU_LISTEN:
933 		if (nsp->nsp_lport == 0)
934 			error = ns_pcbbind(nsp, (struct mbuf *)0);
935 		if (error == 0)
936 			cb->s_state = TCPS_LISTEN;
937 		break;
938 
939 	/*
940 	 * Initiate connection to peer.
941 	 * Enter SYN_SENT state, and mark socket as connecting.
942 	 * Start keep-alive timer, setup prototype header,
943 	 * Send initial system packet requesting connection.
944 	 */
945 	case PRU_CONNECT:
946 		if (nsp->nsp_lport == 0) {
947 			error = ns_pcbbind(nsp, (struct mbuf *)0);
948 			if (error)
949 				break;
950 		}
951 		error = ns_pcbconnect(nsp, nam);
952 		if (error)
953 			break;
954 		soisconnecting(so);
955 		cb->s_state = TCPS_SYN_SENT;
956 		cb->s_did = 0;
957 		spp_template(cb);
958 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
959 		cb->s_force = 1 + TCPTV_KEEP;
960 		/*
961 		 * Other party is required to respond to
962 		 * the port I send from, but he is not
963 		 * required to answer from where I am sending to,
964 		 * so allow wildcarding.
965 		 * original port I am sending to is still saved in
966 		 * cb->s_dport.
967 		 */
968 		nsp->nsp_fport = 0;
969 		error = spp_output(cb, (struct mbuf *) 0);
970 		break;
971 
972 	case PRU_CONNECT2:
973 		error = EOPNOTSUPP;
974 		break;
975 
976 	/*
977 	 * We may decide later to implement connection closing
978 	 * handshaking at the spp level optionally.
979 	 * here is the hook to do it:
980 	 */
981 	case PRU_DISCONNECT:
982 		cb = spp_disconnect(cb);
983 		break;
984 
985 	/*
986 	 * Accept a connection.  Essentially all the work is
987 	 * done at higher levels; just return the address
988 	 * of the peer, storing through addr.
989 	 */
990 	case PRU_ACCEPT: {
991 		struct sockaddr_ns *sns = mtod(nam, struct sockaddr_ns *);
992 
993 		nam->m_len = sizeof (struct sockaddr_ns);
994 		sns->sns_family = AF_NS;
995 		sns->sns_addr = nsp->nsp_faddr;
996 		break;
997 		}
998 
999 	case PRU_SHUTDOWN:
1000 		socantsendmore(so);
1001 		cb = spp_usrclosed(cb);
1002 		if (cb)
1003 			error = spp_output(cb, (struct mbuf *) 0);
1004 		break;
1005 
1006 	/*
1007 	 * After a receive, possibly send acknowledgment
1008 	 * updating allocation.
1009 	 */
1010 	case PRU_RCVD:
1011 		(void) spp_output(cb, (struct mbuf *) 0);
1012 		break;
1013 
1014 	case PRU_SEND:
1015 		error = spp_output(cb, m);
1016 		m = NULL;
1017 		break;
1018 
1019 	case PRU_ABORT:
1020 		(void) spp_drop(cb, ECONNABORTED);
1021 		break;
1022 
1023 	case PRU_SENSE:
1024 	case PRU_CONTROL:
1025 		m = NULL;
1026 		error = EOPNOTSUPP;
1027 		break;
1028 
1029 	case PRU_RCVOOB:
1030 		if ( ! (cb->s_oobflags & SF_IOOB) ) {
1031 			error = EWOULDBLOCK;
1032 			break;
1033 		}
1034 		m->m_len = 1;
1035 		*mtod(m, caddr_t) = cb->s_iobc;
1036 		cb->s_oobflags &= ~ SF_IOOB;
1037 		break;
1038 
1039 	case PRU_SENDOOB:
1040 		if (sbspace(&so->so_snd) < -512) {
1041 			m_freem(m);
1042 			error = ENOBUFS;
1043 			break;
1044 		}
1045 		cb->s_oobflags |= SF_SOOB;
1046 		error = spp_output(cb, m);
1047 		m = NULL;
1048 		cb->s_oobflags &= ~SF_SOOB;
1049 		break;
1050 
1051 	case PRU_SOCKADDR:
1052 		ns_setsockaddr(nsp, nam);
1053 		break;
1054 
1055 	case PRU_PEERADDR:
1056 		ns_setpeeraddr(nsp, nam);
1057 		break;
1058 
1059 	case PRU_SLOWTIMO:
1060 		cb = spp_timers(cb, (int)nam);
1061 		break;
1062 
1063 	case PRU_FASTTIMO:
1064 	case PRU_PROTORCV:
1065 	case PRU_PROTOSEND:
1066 		error =  EOPNOTSUPP;
1067 		break;
1068 
1069 	default:
1070 		panic("sp_usrreq");
1071 	}
1072 	if (cb && (so->so_options & SO_DEBUG || traceallspps))
1073 		spp_trace(SA_USER, (u_char)ostate, cb, (struct spidp *)0, req);
1074 release:
1075 	if (m != NULL)
1076 		m_freem(m);
1077 	splx(s);
1078 	return (error);
1079 }
1080 
1081 spp_usrreq_sp(so, req, m, nam, rights)
1082 	struct socket *so;
1083 	int req;
1084 	struct mbuf *m, *nam, *rights;
1085 {
1086 	int error = spp_usrreq(so, req, m, nam, rights);
1087 
1088 	if (req == PRU_ATTACH && error == 0) {
1089 		struct nspcb *nsp = sotonspcb(so);
1090 		((struct sppcb *)nsp->nsp_pcb)->s_flags |=
1091 					(SF_HI | SF_HO | SF_PI);
1092 	}
1093 	return (error);
1094 }
1095 
1096 /*
1097  * Create template to be used to send spp packets on a connection.
1098  * Called after host entry created, fills
1099  * in a skeletal spp header (choosing connection id),
1100  * minimizing the amount of work necessary when the connection is used.
1101  */
1102 spp_template(cb)
1103 	struct sppcb *cb;
1104 {
1105 	register struct nspcb *nsp = cb->s_nspcb;
1106 	register struct spidp *n = &(cb->s_shdr);
1107 
1108 	cb->s_mtu = 576 - sizeof (struct spidp);
1109 	n->si_pt = NSPROTO_SPP;
1110 	n->si_sna = nsp->nsp_laddr;
1111 	n->si_dna = nsp->nsp_faddr;
1112 	n->si_sid = htons(spp_iss);
1113 	spp_iss += SPP_ISSINCR/2;
1114 	n->si_alo = 1;
1115 }
1116 
1117 /*
1118  * Close a SPIP control block:
1119  *	discard spp control block itself
1120  *	discard ns protocol control block
1121  *	wake up any sleepers
1122  */
1123 struct sppcb *
1124 spp_close(cb)
1125 	register struct sppcb *cb;
1126 {
1127 	register struct spidp_q *s;
1128 	struct nspcb *nsp = cb->s_nspcb;
1129 	struct socket *so = nsp->nsp_socket;
1130 	register struct mbuf *m;
1131 
1132 	s = cb->s_q.si_next;
1133 	while (s != &(cb->s_q)) {
1134 		s = s->si_next;
1135 		m = dtom(s->si_prev);
1136 		remque(s->si_prev);
1137 		m_freem(m);
1138 	}
1139 	(void) m_free(dtom(cb));
1140 	nsp->nsp_pcb = 0;
1141 	soisdisconnected(so);
1142 	ns_pcbdetach(nsp);
1143 	return ((struct sppcb *)0);
1144 }
1145 /*
1146  *	Someday we may do level 3 handshaking
1147  *	to close a connection or send a xerox style error.
1148  *	For now, just close.
1149  */
1150 struct sppcb *
1151 spp_usrclosed(cb)
1152 	register struct sppcb *cb;
1153 {
1154 	return (spp_close(cb));
1155 }
1156 struct sppcb *
1157 spp_disconnect(cb)
1158 	register struct sppcb *cb;
1159 {
1160 	return (spp_close(cb));
1161 }
1162 /*
1163  * Drop connection, reporting
1164  * the specified error.
1165  */
1166 struct sppcb *
1167 spp_drop(cb, errno)
1168 	register struct sppcb *cb;
1169 	int errno;
1170 {
1171 	struct socket *so = cb->s_nspcb->nsp_socket;
1172 
1173 	/*
1174 	 * someday, in the xerox world
1175 	 * we will generate error protocol packets
1176 	 * announcing that the socket has gone away.
1177 	 */
1178 	/*if (TCPS_HAVERCVDSYN(tp->t_state)) {
1179 		tp->t_state = TCPS_CLOSED;
1180 		(void) tcp_output(tp);
1181 	}*/
1182 	so->so_error = errno;
1183 	return (spp_close(cb));
1184 }
1185 
1186 spp_abort(nsp)
1187 	struct nspcb *nsp;
1188 {
1189 
1190 	(void) spp_close((struct sppcb *)nsp->nsp_pcb);
1191 }
1192 
1193 spp_setpersist(cb)
1194 	register struct sppcb *cb;
1195 {
1196 
1197 	/*if (cb->s_timer[TCPT_REXMT])
1198 		panic("spp_output REXMT");*/
1199 	/*
1200 	 * Start/restart persistance timer.
1201 	 */
1202 	TCPT_RANGESET(cb->s_timer[TCPT_PERSIST],
1203 	    ((int)(tcp_beta * cb->s_srtt)) << cb->s_rxtshift,
1204 	    TCPTV_PERSMIN, TCPTV_MAX);
1205 	cb->s_rxtshift++;
1206 	if (cb->s_rxtshift >= TCP_MAXRXTSHIFT)
1207 		cb->s_rxtshift = 0;
1208 }
1209 /*
1210  * Fast timeout routine for processing delayed acks
1211  */
1212 int spp_ftcnt;
1213 spp_fasttimo()
1214 {
1215 	register struct nspcb *nsp;
1216 	register struct sppcb *cb;
1217 	int s = splnet();
1218 
1219 	nsp = nspcb.nsp_next;
1220 	spp_ftcnt++;
1221 	if (nsp)
1222 	for (; nsp != &nspcb; nsp = nsp->nsp_next)
1223 		if ((cb = (struct sppcb *)nsp->nsp_pcb) &&
1224 		    (cb->s_flags & SF_DELACK)) {
1225 			cb->s_flags &= ~SF_DELACK;
1226 			cb->s_flags |= SF_AK;
1227 			(void) spp_output(cb, (struct mbuf *) 0);
1228 		}
1229 	splx(s);
1230 }
1231 
1232 /*
1233  * spp protocol timeout routine called every 500 ms.
1234  * Updates the timers in all active pcb's and
1235  * causes finite state machine actions if timers expire.
1236  */
1237 spp_slowtimo()
1238 {
1239 	register struct nspcb *ip, *ipnxt;
1240 	register struct sppcb *cb;
1241 	int s = splnet();
1242 	register int i;
1243 
1244 	/*
1245 	 * Search through tcb's and update active timers.
1246 	 */
1247 	ip = nspcb.nsp_next;
1248 	if (ip == 0) {
1249 		splx(s);
1250 		return;
1251 	}
1252 	while (ip != &nspcb) {
1253 		cb = nstosppcb(ip);
1254 		ipnxt = ip->nsp_next;
1255 		if (cb == 0)
1256 			goto tpgone;
1257 		for (i = 0; i < TCPT_NTIMERS; i++) {
1258 			if (cb->s_timer[i] && --cb->s_timer[i] == 0) {
1259 				(void) spp_usrreq(cb->s_nspcb->nsp_socket,
1260 				    PRU_SLOWTIMO, (struct mbuf *)0,
1261 				    (struct mbuf *)i, (struct mbuf *)0);
1262 				if (ipnxt->nsp_prev != ip)
1263 					goto tpgone;
1264 			}
1265 		}
1266 		cb->s_idle++;
1267 		if (cb->s_rtt)
1268 			cb->s_rtt++;
1269 tpgone:
1270 		ip = ipnxt;
1271 	}
1272 	spp_iss += SPP_ISSINCR/PR_SLOWHZ;		/* increment iss */
1273 	splx(s);
1274 }
1275 
1276 float	spp_backoff[TCP_MAXRXTSHIFT] =
1277     { 1.0, 1.2, 1.4, 1.7, 2.0, 3.0, 5.0, 8.0, 16.0, 32.0 };
1278 int sppexprexmtbackoff = 0;
1279 /*
1280  * SPP timer processing.
1281  */
1282 struct sppcb *
1283 spp_timers(cb, timer)
1284 	register struct sppcb *cb;
1285 	int timer;
1286 {
1287 
1288 	cb->s_force = 1 + timer;
1289 	switch (timer) {
1290 
1291 	/*
1292 	 * 2 MSL timeout in shutdown went off.  Delete connection
1293 	 * control block.
1294 	 */
1295 	case TCPT_2MSL:
1296 		cb = spp_close(cb);
1297 		break;
1298 
1299 	/*
1300 	 * Retransmission timer went off.  Message has not
1301 	 * been acked within retransmit interval.  Back off
1302 	 * to a longer retransmit interval and retransmit all
1303 	 * unacknowledged messages in the window.
1304 	 */
1305 	case TCPT_REXMT:
1306 		cb->s_rxtshift++;
1307 		if (cb->s_rxtshift > TCP_MAXRXTSHIFT) {
1308 			cb = spp_drop(cb, ETIMEDOUT);
1309 			break;
1310 		}
1311 		(void) spp_output(cb, (struct mbuf *) 0);
1312 		TCPT_RANGESET(cb->s_timer[TCPT_REXMT],
1313 		    (int)cb->s_srtt, TCPTV_MIN, TCPTV_MAX);
1314 		if (sppexprexmtbackoff) {
1315 			TCPT_RANGESET(cb->s_timer[TCPT_REXMT],
1316 			    cb->s_timer[TCPT_REXMT] << cb->s_rxtshift,
1317 			    TCPTV_MIN, TCPTV_MAX);
1318 		} else {
1319 			TCPT_RANGESET(cb->s_timer[TCPT_REXMT],
1320 			    cb->s_timer[TCPT_REXMT] *
1321 			        spp_backoff[cb->s_rxtshift - 1],
1322 			    TCPTV_MIN, TCPTV_MAX);
1323 		}
1324 		break;
1325 
1326 	/*
1327 	 * Persistance timer into zero window.
1328 	 * Force a probe to be sent.
1329 	 */
1330 	case TCPT_PERSIST:
1331 		(void) spp_output(cb, (struct mbuf *) 0);
1332 		spp_setpersist(cb);
1333 		break;
1334 
1335 	/*
1336 	 * Keep-alive timer went off; send something
1337 	 * or drop connection if idle for too long.
1338 	 */
1339 	case TCPT_KEEP:
1340 		if (cb->s_state < TCPS_ESTABLISHED)
1341 			goto dropit;
1342 		if (cb->s_nspcb->nsp_socket->so_options & SO_KEEPALIVE) {
1343 		    	if (cb->s_idle >= TCPTV_MAXIDLE)
1344 				goto dropit;
1345 			(void) spp_output(cb, (struct mbuf *) 0);
1346 		} else
1347 			cb->s_idle = 0;
1348 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
1349 		break;
1350 	dropit:
1351 		cb = spp_drop(cb, ETIMEDOUT);
1352 		break;
1353 	}
1354 	return (cb);
1355 }
1356