xref: /csrg-svn/sys/netns/spp_usrreq.c (revision 37473)
1 /*
2  * Copyright (c) 1984, 1985, 1986, 1987 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  *
17  *	@(#)spp_usrreq.c	7.10 (Berkeley) 04/22/89
18  */
19 
20 #include "param.h"
21 #include "systm.h"
22 #include "dir.h"
23 #include "user.h"
24 #include "malloc.h"
25 #include "mbuf.h"
26 #include "protosw.h"
27 #include "socket.h"
28 #include "socketvar.h"
29 #include "errno.h"
30 
31 #include "../net/if.h"
32 #include "../net/route.h"
33 #include "../netinet/tcp_fsm.h"
34 
35 #include "ns.h"
36 #include "ns_pcb.h"
37 #include "idp.h"
38 #include "idp_var.h"
39 #include "ns_error.h"
40 #include "sp.h"
41 #include "spidp.h"
42 #include "spp_timer.h"
43 #include "spp_var.h"
44 #include "spp_debug.h"
45 
46 /*
47  * SP protocol implementation.
48  */
49 spp_init()
50 {
51 
52 	spp_iss = 1; /* WRONG !! should fish it out of TODR */
53 }
54 struct spidp spp_savesi;
55 int traceallspps = 0;
56 extern int sppconsdebug;
57 int spp_hardnosed;
58 int spp_use_delack = 0;
59 u_short spp_newchecks[50];
60 
61 /*ARGSUSED*/
62 spp_input(m, nsp)
63 	register struct mbuf *m;
64 	register struct nspcb *nsp;
65 {
66 	register struct sppcb *cb;
67 	register struct spidp *si = mtod(m, struct spidp *);
68 	register struct socket *so;
69 	short ostate;
70 	int dropsocket = 0;
71 
72 
73 	sppstat.spps_rcvtotal++;
74 	if (nsp == 0) {
75 		panic("No nspcb in spp_input\n");
76 		return;
77 	}
78 
79 	cb = nstosppcb(nsp);
80 	if (cb == 0) goto bad;
81 
82 	if (m->m_len < sizeof(*si)) {
83 		if ((m = m_pullup(m, sizeof(*si))) == 0) {
84 			sppstat.spps_rcvshort++;
85 			return;
86 		}
87 		si = mtod(m, struct spidp *);
88 	}
89 	si->si_seq = ntohs(si->si_seq);
90 	si->si_ack = ntohs(si->si_ack);
91 	si->si_alo = ntohs(si->si_alo);
92 
93 	so = nsp->nsp_socket;
94 	if (so->so_options & SO_DEBUG || traceallspps) {
95 		ostate = cb->s_state;
96 		spp_savesi = *si;
97 	}
98 	if (so->so_options & SO_ACCEPTCONN) {
99 		struct sppcb *ocb = cb;
100 
101 		so = sonewconn(so);
102 		if (so == 0) {
103 			goto drop;
104 		}
105 		/*
106 		 * This is ugly, but ....
107 		 *
108 		 * Mark socket as temporary until we're
109 		 * committed to keeping it.  The code at
110 		 * ``drop'' and ``dropwithreset'' check the
111 		 * flag dropsocket to see if the temporary
112 		 * socket created here should be discarded.
113 		 * We mark the socket as discardable until
114 		 * we're committed to it below in TCPS_LISTEN.
115 		 */
116 		dropsocket++;
117 		nsp = (struct nspcb *)so->so_pcb;
118 		nsp->nsp_laddr = si->si_dna;
119 		cb = nstosppcb(nsp);
120 		cb->s_mtu = ocb->s_mtu;		/* preserve sockopts */
121 		cb->s_flags = ocb->s_flags;	/* preserve sockopts */
122 		cb->s_flags2 = ocb->s_flags2;	/* preserve sockopts */
123 		cb->s_state = TCPS_LISTEN;
124 	}
125 
126 	/*
127 	 * Packet received on connection.
128 	 * reset idle time and keep-alive timer;
129 	 */
130 	cb->s_idle = 0;
131 	cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
132 
133 	switch (cb->s_state) {
134 
135 	case TCPS_LISTEN:{
136 		struct mbuf *am;
137 		register struct sockaddr_ns *sns;
138 		struct ns_addr laddr;
139 
140 		/*
141 		 * If somebody here was carying on a conversation
142 		 * and went away, and his pen pal thinks he can
143 		 * still talk, we get the misdirected packet.
144 		 */
145 		if (spp_hardnosed && (si->si_did != 0 || si->si_seq != 0)) {
146 			spp_istat.gonawy++;
147 			goto dropwithreset;
148 		}
149 		am = m_get(M_DONTWAIT, MT_SONAME);
150 		if (am == NULL)
151 			goto drop;
152 		am->m_len = sizeof (struct sockaddr_ns);
153 		sns = mtod(am, struct sockaddr_ns *);
154 		sns->sns_len = sizeof(*sns);
155 		sns->sns_family = AF_NS;
156 		sns->sns_addr = si->si_sna;
157 		laddr = nsp->nsp_laddr;
158 		if (ns_nullhost(laddr))
159 			nsp->nsp_laddr = si->si_dna;
160 		if (ns_pcbconnect(nsp, am)) {
161 			nsp->nsp_laddr = laddr;
162 			(void) m_free(am);
163 			spp_istat.noconn++;
164 			goto drop;
165 		}
166 		(void) m_free(am);
167 		spp_template(cb);
168 		dropsocket = 0;		/* committed to socket */
169 		cb->s_did = si->si_sid;
170 		cb->s_rack = si->si_ack;
171 		cb->s_ralo = si->si_alo;
172 #define THREEWAYSHAKE
173 #ifdef THREEWAYSHAKE
174 		cb->s_state = TCPS_SYN_RECEIVED;
175 		cb->s_force = 1 + SPPT_KEEP;
176 		sppstat.spps_accepts++;
177 		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
178 		}
179 		break;
180 	/*
181 	 * This state means that we have heard a response
182 	 * to our acceptance of their connection
183 	 * It is probably logically unnecessary in this
184 	 * implementation.
185 	 */
186 	 case TCPS_SYN_RECEIVED: {
187 		if (si->si_did!=cb->s_sid) {
188 			spp_istat.wrncon++;
189 			goto drop;
190 		}
191 #endif
192 		nsp->nsp_fport =  si->si_sport;
193 		cb->s_timer[SPPT_REXMT] = 0;
194 		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
195 		soisconnected(so);
196 		cb->s_state = TCPS_ESTABLISHED;
197 		sppstat.spps_accepts++;
198 		}
199 		break;
200 
201 	/*
202 	 * This state means that we have gotten a response
203 	 * to our attempt to establish a connection.
204 	 * We fill in the data from the other side,
205 	 * telling us which port to respond to, instead of the well-
206 	 * known one we might have sent to in the first place.
207 	 * We also require that this is a response to our
208 	 * connection id.
209 	 */
210 	case TCPS_SYN_SENT:
211 		if (si->si_did!=cb->s_sid) {
212 			spp_istat.notme++;
213 			goto drop;
214 		}
215 		sppstat.spps_connects++;
216 		cb->s_did = si->si_sid;
217 		cb->s_rack = si->si_ack;
218 		cb->s_ralo = si->si_alo;
219 		cb->s_dport = nsp->nsp_fport =  si->si_sport;
220 		cb->s_timer[SPPT_REXMT] = 0;
221 		cb->s_flags |= SF_ACKNOW;
222 		soisconnected(so);
223 		cb->s_state = TCPS_ESTABLISHED;
224 		/* Use roundtrip time of connection request for initial rtt */
225 		if (cb->s_rtt) {
226 			cb->s_srtt = cb->s_rtt << 3;
227 			cb->s_rttvar = cb->s_rtt << 1;
228 			SPPT_RANGESET(cb->s_rxtcur,
229 			    ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1,
230 			    SPPTV_MIN, SPPTV_REXMTMAX);
231 			    cb->s_rtt = 0;
232 		}
233 	}
234 	if (so->so_options & SO_DEBUG || traceallspps)
235 		spp_trace(SA_INPUT, (u_char)ostate, cb, &spp_savesi, 0);
236 
237 	m->m_len -= sizeof (struct idp);
238 	m->m_pkthdr.len -= sizeof (struct idp);
239 	m->m_data += sizeof (struct idp);
240 
241 	if (spp_reass(cb, si)) {
242 		(void) m_freem(m);
243 	}
244 	if (cb->s_force || (cb->s_flags & (SF_ACKNOW|SF_WIN|SF_RXT)))
245 		(void) spp_output(cb, (struct mbuf *)0);
246 	cb->s_flags &= ~(SF_WIN|SF_RXT);
247 	return;
248 
249 dropwithreset:
250 	if (dropsocket)
251 		(void) soabort(so);
252 	si->si_seq = ntohs(si->si_seq);
253 	si->si_ack = ntohs(si->si_ack);
254 	si->si_alo = ntohs(si->si_alo);
255 	ns_error(dtom(si), NS_ERR_NOSOCK, 0);
256 	if (cb->s_nspcb->nsp_socket->so_options & SO_DEBUG || traceallspps)
257 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
258 	return;
259 
260 drop:
261 bad:
262 	if (cb == 0 || cb->s_nspcb->nsp_socket->so_options & SO_DEBUG ||
263             traceallspps)
264 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
265 	m_freem(m);
266 }
267 
268 int spprexmtthresh = 3;
269 
270 /*
271  * This is structurally similar to the tcp reassembly routine
272  * but its function is somewhat different:  It merely queues
273  * packets up, and suppresses duplicates.
274  */
275 spp_reass(cb, si)
276 register struct sppcb *cb;
277 register struct spidp *si;
278 {
279 	register struct spidp_q *q;
280 	register struct mbuf *m;
281 	register struct socket *so = cb->s_nspcb->nsp_socket;
282 	char packetp = cb->s_flags & SF_HI;
283 	int incr;
284 	char wakeup = 0;
285 
286 	if (si == SI(0))
287 		goto present;
288 	/*
289 	 * Update our news from them.
290 	 */
291 	if (si->si_cc & SP_SA)
292 		cb->s_flags |= (spp_use_delack ? SF_DELACK : SF_ACKNOW);
293 	if (SSEQ_GT(si->si_alo, cb->s_ralo))
294 		cb->s_flags |= SF_WIN;
295 	if (SSEQ_LEQ(si->si_ack, cb->s_rack)) {
296 		if ((si->si_cc & SP_SP) && cb->s_rack != (cb->s_smax + 1)) {
297 			sppstat.spps_rcvdupack++;
298 			/*
299 			 * If this is a completely duplicate ack
300 			 * and other conditions hold, we assume
301 			 * a packet has been dropped and retransmit
302 			 * it exactly as in tcp_input().
303 			 */
304 			if (si->si_ack != cb->s_rack ||
305 			    si->si_alo != cb->s_ralo)
306 				cb->s_dupacks = 0;
307 			else if (++cb->s_dupacks == spprexmtthresh) {
308 				u_short onxt = cb->s_snxt;
309 				int cwnd = cb->s_cwnd;
310 
311 				cb->s_snxt = si->si_ack;
312 				cb->s_cwnd = CUNIT;
313 				cb->s_force = 1 + SPPT_REXMT;
314 				(void) spp_output(cb, (struct mbuf *)0);
315 				cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
316 				cb->s_rtt = 0;
317 				if (cwnd >= 4 * CUNIT)
318 					cb->s_cwnd = cwnd / 2;
319 				if (SSEQ_GT(onxt, cb->s_snxt))
320 					cb->s_snxt = onxt;
321 				return (1);
322 			}
323 		} else
324 			cb->s_dupacks = 0;
325 		goto update_window;
326 	}
327 	cb->s_dupacks = 0;
328 	/*
329 	 * If our correspondent acknowledges data we haven't sent
330 	 * TCP would drop the packet after acking.  We'll be a little
331 	 * more permissive
332 	 */
333 	if (SSEQ_GT(si->si_ack, (cb->s_smax + 1))) {
334 		sppstat.spps_rcvacktoomuch++;
335 		si->si_ack = cb->s_smax + 1;
336 	}
337 	sppstat.spps_rcvackpack++;
338 	/*
339 	 * If transmit timer is running and timed sequence
340 	 * number was acked, update smoothed round trip time.
341 	 * See discussion of algorithm in tcp_input.c
342 	 */
343 	if (cb->s_rtt && SSEQ_GT(si->si_ack, cb->s_rtseq)) {
344 		sppstat.spps_rttupdated++;
345 		if (cb->s_srtt != 0) {
346 			register short delta;
347 			delta = cb->s_rtt - (cb->s_srtt >> 3);
348 			if ((cb->s_srtt += delta) <= 0)
349 				cb->s_srtt = 1;
350 			if (delta < 0)
351 				delta = -delta;
352 			delta -= (cb->s_rttvar >> 2);
353 			if ((cb->s_rttvar += delta) <= 0)
354 				cb->s_rttvar = 1;
355 		} else {
356 			/*
357 			 * No rtt measurement yet
358 			 */
359 			cb->s_srtt = cb->s_rtt << 3;
360 			cb->s_rttvar = cb->s_rtt << 1;
361 		}
362 		cb->s_rtt = 0;
363 		cb->s_rxtshift = 0;
364 		SPPT_RANGESET(cb->s_rxtcur,
365 			((cb->s_srtt >> 2) + cb->s_rttvar) >> 1,
366 			SPPTV_MIN, SPPTV_REXMTMAX);
367 	}
368 	/*
369 	 * If all outstanding data is acked, stop retransmit
370 	 * timer and remember to restart (more output or persist).
371 	 * If there is more data to be acked, restart retransmit
372 	 * timer, using current (possibly backed-off) value;
373 	 */
374 	if (si->si_ack == cb->s_smax + 1) {
375 		cb->s_timer[SPPT_REXMT] = 0;
376 		cb->s_flags |= SF_RXT;
377 	} else if (cb->s_timer[SPPT_PERSIST] == 0)
378 		cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
379 	/*
380 	 * When new data is acked, open the congestion window.
381 	 * If the window gives us less than ssthresh packets
382 	 * in flight, open exponentially (maxseg at a time).
383 	 * Otherwise open linearly (maxseg^2 / cwnd at a time).
384 	 */
385 	incr = CUNIT;
386 	if (cb->s_cwnd > cb->s_ssthresh)
387 		incr = max(incr * incr / cb->s_cwnd, 1);
388 	cb->s_cwnd = min(cb->s_cwnd + incr, cb->s_cwmx);
389 	/*
390 	 * Trim Acked data from output queue.
391 	 */
392 	while ((m = so->so_snd.sb_mb) != NULL) {
393 		if (SSEQ_LT((mtod(m, struct spidp *))->si_seq, si->si_ack))
394 			sbdroprecord(&so->so_snd);
395 		else
396 			break;
397 	}
398 	sowwakeup(so);
399 	cb->s_rack = si->si_ack;
400 update_window:
401 	if (SSEQ_LT(cb->s_snxt, cb->s_rack))
402 		cb->s_snxt = cb->s_rack;
403 	if (SSEQ_LT(cb->s_swl1, si->si_seq) || cb->s_swl1 == si->si_seq &&
404 	    (SSEQ_LT(cb->s_swl2, si->si_ack) ||
405 	     cb->s_swl2 == si->si_ack && SSEQ_LT(cb->s_ralo, si->si_alo))) {
406 		/* keep track of pure window updates */
407 		if ((si->si_cc & SP_SP) && cb->s_swl2 == si->si_ack
408 		    && SSEQ_LT(cb->s_ralo, si->si_alo)) {
409 			sppstat.spps_rcvwinupd++;
410 			sppstat.spps_rcvdupack--;
411 		}
412 		cb->s_ralo = si->si_alo;
413 		cb->s_swl1 = si->si_seq;
414 		cb->s_swl2 = si->si_ack;
415 		cb->s_swnd = (1 + si->si_alo - si->si_ack);
416 		if (cb->s_swnd > cb->s_smxw)
417 			cb->s_smxw = cb->s_swnd;
418 		cb->s_flags |= SF_WIN;
419 	}
420 	/*
421 	 * If this packet number is higher than that which
422 	 * we have allocated refuse it, unless urgent
423 	 */
424 	if (SSEQ_GT(si->si_seq, cb->s_alo)) {
425 		if (si->si_cc & SP_SP) {
426 			sppstat.spps_rcvwinprobe++;
427 			return (1);
428 		} else
429 			sppstat.spps_rcvpackafterwin++;
430 		if (si->si_cc & SP_OB) {
431 			if (SSEQ_GT(si->si_seq, cb->s_alo + 60)) {
432 				ns_error(dtom(si), NS_ERR_FULLUP, 0);
433 				return (0);
434 			} /* else queue this packet; */
435 		} else {
436 			/*register struct socket *so = cb->s_nspcb->nsp_socket;
437 			if (so->so_state && SS_NOFDREF) {
438 				ns_error(dtom(si), NS_ERR_NOSOCK, 0);
439 				(void)spp_close(cb);
440 			} else
441 				       would crash system*/
442 			spp_istat.notyet++;
443 			ns_error(dtom(si), NS_ERR_FULLUP, 0);
444 			return (0);
445 		}
446 	}
447 	/*
448 	 * If this is a system packet, we don't need to
449 	 * queue it up, and won't update acknowledge #
450 	 */
451 	if (si->si_cc & SP_SP) {
452 		return (1);
453 	}
454 	/*
455 	 * We have already seen this packet, so drop.
456 	 */
457 	if (SSEQ_LT(si->si_seq, cb->s_ack)) {
458 		spp_istat.bdreas++;
459 		sppstat.spps_rcvduppack++;
460 		if (si->si_seq == cb->s_ack - 1)
461 			spp_istat.lstdup++;
462 		return (1);
463 	}
464 	/*
465 	 * Loop through all packets queued up to insert in
466 	 * appropriate sequence.
467 	 */
468 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
469 		if (si->si_seq == SI(q)->si_seq) {
470 			sppstat.spps_rcvduppack++;
471 			return (1);
472 		}
473 		if (SSEQ_LT(si->si_seq, SI(q)->si_seq)) {
474 			sppstat.spps_rcvoopack++;
475 			break;
476 		}
477 	}
478 	insque(si, q->si_prev);
479 	/*
480 	 * If this packet is urgent, inform process
481 	 */
482 	if (si->si_cc & SP_OB) {
483 		cb->s_iobc = ((char *)si)[1 + sizeof(*si)];
484 		sohasoutofband(so);
485 		cb->s_oobflags |= SF_IOOB;
486 	}
487 present:
488 #define SPINC sizeof(struct sphdr)
489 	/*
490 	 * Loop through all packets queued up to update acknowledge
491 	 * number, and present all acknowledged data to user;
492 	 * If in packet interface mode, show packet headers.
493 	 */
494 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
495 		  if (SI(q)->si_seq == cb->s_ack) {
496 			cb->s_ack++;
497 			m = dtom(q);
498 			if (SI(q)->si_cc & SP_OB) {
499 				cb->s_oobflags &= ~SF_IOOB;
500 				if (so->so_rcv.sb_cc)
501 					so->so_oobmark = so->so_rcv.sb_cc;
502 				else
503 					so->so_state |= SS_RCVATMARK;
504 			}
505 			q = q->si_prev;
506 			remque(q->si_next);
507 			wakeup = 1;
508 			sppstat.spps_rcvpack++;
509 #ifdef SF_NEWCALL
510 			if (cb->s_flags2 & SF_NEWCALL) {
511 				struct sphdr *sp = mtod(m, struct sphdr *);
512 				u_char dt = sp->sp_dt;
513 				spp_newchecks[4]++;
514 				if (dt != cb->s_rhdr.sp_dt) {
515 					struct mbuf *mm =
516 					   m_getclr(M_DONTWAIT, MT_CONTROL);
517 					spp_newchecks[0]++;
518 					if (mm != NULL) {
519 						u_short *s =
520 							mtod(mm, u_short *);
521 						cb->s_rhdr.sp_dt = dt;
522 						mm->m_len = 5; /*XXX*/
523 						s[0] = 5;
524 						s[1] = 1;
525 						*(u_char *)(&s[2]) = dt;
526 						sbappend(&so->so_rcv, mm);
527 					}
528 				}
529 				if (sp->sp_cc & SP_OB) {
530 					MCHTYPE(m, MT_OOBDATA);
531 					spp_newchecks[1]++;
532 					so->so_oobmark = 0;
533 					so->so_state &= ~SS_RCVATMARK;
534 				}
535 				if (packetp == 0) {
536 					m->m_data += SPINC;
537 					m->m_len -= SPINC;
538 					m->m_pkthdr.len -= SPINC;
539 				}
540 				if ((sp->sp_cc & SP_EM) || packetp) {
541 					sbappendrecord(&so->so_rcv, m);
542 					spp_newchecks[9]++;
543 				} else
544 					sbappend(&so->so_rcv, m);
545 			} else
546 #endif
547 			if (packetp) {
548 				sbappendrecord(&so->so_rcv, m);
549 			} else {
550 				cb->s_rhdr = *mtod(m, struct sphdr *);
551 				m->m_data += SPINC;
552 				m->m_len -= SPINC;
553 				m->m_pkthdr.len -= SPINC;
554 				sbappend(&so->so_rcv, m);
555 			}
556 		  } else
557 			break;
558 	}
559 	if (wakeup) sorwakeup(so);
560 	return (0);
561 }
562 
563 spp_ctlinput(cmd, arg)
564 	int cmd;
565 	caddr_t arg;
566 {
567 	struct ns_addr *na;
568 	extern u_char nsctlerrmap[];
569 	extern spp_abort(), spp_quench();
570 	extern struct nspcb *idp_drop();
571 	struct ns_errp *errp;
572 	struct nspcb *nsp;
573 	struct sockaddr_ns *sns;
574 	int type;
575 
576 	if (cmd < 0 || cmd > PRC_NCMDS)
577 		return;
578 	type = NS_ERR_UNREACH_HOST;
579 
580 	switch (cmd) {
581 
582 	case PRC_ROUTEDEAD:
583 		return;
584 
585 	case PRC_IFDOWN:
586 	case PRC_HOSTDEAD:
587 	case PRC_HOSTUNREACH:
588 		sns = (struct sockaddr_ns *)arg;
589 		if (sns->sns_family != AF_NS)
590 			return;
591 		na = &sns->sns_addr;
592 		break;
593 
594 	default:
595 		errp = (struct ns_errp *)arg;
596 		na = &errp->ns_err_idp.idp_dna;
597 		type = errp->ns_err_num;
598 		type = ntohs((u_short)type);
599 	}
600 	switch (type) {
601 
602 	case NS_ERR_UNREACH_HOST:
603 		ns_pcbnotify(na, (int)nsctlerrmap[cmd], spp_abort, (long) 0);
604 		break;
605 
606 	case NS_ERR_TOO_BIG:
607 	case NS_ERR_NOSOCK:
608 		nsp = ns_pcblookup(na, errp->ns_err_idp.idp_sna.x_port,
609 			NS_WILDCARD);
610 		if (nsp) {
611 			if(nsp->nsp_pcb)
612 				(void) spp_drop((struct sppcb *)nsp->nsp_pcb,
613 						(int)nsctlerrmap[cmd]);
614 			else
615 				(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
616 		}
617 		break;
618 
619 	case NS_ERR_FULLUP:
620 		ns_pcbnotify(na, 0, spp_quench, (long) 0);
621 	}
622 }
623 /*
624  * When a source quench is received, close congestion window
625  * to one packet.  We will gradually open it again as we proceed.
626  */
627 spp_quench(nsp)
628 	struct nspcb *nsp;
629 {
630 	struct sppcb *cb = nstosppcb(nsp);
631 
632 	if (cb)
633 		cb->s_cwnd = CUNIT;
634 }
635 
636 #ifdef notdef
637 int
638 spp_fixmtu(nsp)
639 register struct nspcb *nsp;
640 {
641 	register struct sppcb *cb = (struct sppcb *)(nsp->nsp_pcb);
642 	register struct mbuf *m;
643 	register struct spidp *si;
644 	struct ns_errp *ep;
645 	struct sockbuf *sb;
646 	int badseq, len;
647 	struct mbuf *firstbad, *m0;
648 
649 	if (cb) {
650 		/*
651 		 * The notification that we have sent
652 		 * too much is bad news -- we will
653 		 * have to go through queued up so far
654 		 * splitting ones which are too big and
655 		 * reassigning sequence numbers and checksums.
656 		 * we should then retransmit all packets from
657 		 * one above the offending packet to the last one
658 		 * we had sent (or our allocation)
659 		 * then the offending one so that the any queued
660 		 * data at our destination will be discarded.
661 		 */
662 		 ep = (struct ns_errp *)nsp->nsp_notify_param;
663 		 sb = &nsp->nsp_socket->so_snd;
664 		 cb->s_mtu = ep->ns_err_param;
665 		 badseq = SI(&ep->ns_err_idp)->si_seq;
666 		 for (m = sb->sb_mb; m; m = m->m_act) {
667 			si = mtod(m, struct spidp *);
668 			if (si->si_seq == badseq)
669 				break;
670 		 }
671 		 if (m == 0) return;
672 		 firstbad = m;
673 		 /*for (;;) {*/
674 			/* calculate length */
675 			for (m0 = m, len = 0; m ; m = m->m_next)
676 				len += m->m_len;
677 			if (len > cb->s_mtu) {
678 			}
679 		/* FINISH THIS
680 		} */
681 	}
682 }
683 #endif
684 
685 spp_output(cb, m0)
686 	register struct sppcb *cb;
687 	struct mbuf *m0;
688 {
689 	struct socket *so = cb->s_nspcb->nsp_socket;
690 	register struct mbuf *m;
691 	register struct spidp *si = (struct spidp *) 0;
692 	register struct sockbuf *sb = &so->so_snd;
693 	int len = 0, win, rcv_win;
694 	short span, off, recordp = 0;
695 	u_short alo;
696 	int error = 0, sendalot;
697 #ifdef notdef
698 	int idle;
699 #endif
700 	struct mbuf *mprev;
701 	extern int idpcksum;
702 
703 	if (m0) {
704 		int mtu = cb->s_mtu;
705 		int datalen;
706 		/*
707 		 * Make sure that packet isn't too big.
708 		 */
709 		for (m = m0; m ; m = m->m_next) {
710 			mprev = m;
711 			len += m->m_len;
712 			if (m->m_flags & M_EOR)
713 				recordp = 1;
714 		}
715 		datalen = (cb->s_flags & SF_HO) ?
716 				len - sizeof (struct sphdr) : len;
717 		if (datalen > mtu) {
718 			if (cb->s_flags & SF_PI) {
719 				m_freem(m0);
720 				return (EMSGSIZE);
721 			} else {
722 				int oldEM = cb->s_cc & SP_EM;
723 
724 				cb->s_cc &= ~SP_EM;
725 				while (len > mtu) {
726 					/*
727 					 * Here we are only being called
728 					 * from usrreq(), so it is OK to
729 					 * block.
730 					 */
731 					m = m_copym(m0, 0, mtu, M_WAIT);
732 					if (cb->s_flags & SF_NEWCALL) {
733 					    struct mbuf *mm = m;
734 					    spp_newchecks[7]++;
735 					    while (mm) {
736 						mm->m_flags &= ~M_EOR;
737 						mm = mm->m_next;
738 					    }
739 					}
740 					error = spp_output(cb, m);
741 					if (error) {
742 						cb->s_cc |= oldEM;
743 						m_freem(m0);
744 						return(error);
745 					}
746 					m_adj(m0, mtu);
747 					len -= mtu;
748 				}
749 				cb->s_cc |= oldEM;
750 			}
751 		}
752 		/*
753 		 * Force length even, by adding a "garbage byte" if
754 		 * necessary.
755 		 */
756 		if (len & 1) {
757 			m = mprev;
758 			if (M_TRAILINGSPACE(m) >= 1)
759 				m->m_len++;
760 			else {
761 				struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA);
762 
763 				if (m1 == 0) {
764 					m_freem(m0);
765 					return (ENOBUFS);
766 				}
767 				m1->m_len = 1;
768 				*(mtod(m1, u_char *)) = 0;
769 				m->m_next = m1;
770 			}
771 		}
772 		m = m_gethdr(M_DONTWAIT, MT_HEADER);
773 		if (m == 0) {
774 			m_freem(m0);
775 			return (ENOBUFS);
776 		}
777 		/*
778 		 * Fill in mbuf with extended SP header
779 		 * and addresses and length put into network format.
780 		 */
781 		MH_ALIGN(m, sizeof (struct spidp));
782 		m->m_len = sizeof (struct spidp);
783 		m->m_next = m0;
784 		si = mtod(m, struct spidp *);
785 		si->si_i = *cb->s_idp;
786 		si->si_s = cb->s_shdr;
787 		if ((cb->s_flags & SF_PI) && (cb->s_flags & SF_HO)) {
788 			register struct sphdr *sh;
789 			if (m0->m_len < sizeof (*sh)) {
790 				if((m0 = m_pullup(m0, sizeof(*sh))) == NULL) {
791 					(void) m_free(m);
792 					m_freem(m0);
793 					return (EINVAL);
794 				}
795 				m->m_next = m0;
796 			}
797 			sh = mtod(m0, struct sphdr *);
798 			si->si_dt = sh->sp_dt;
799 			si->si_cc |= sh->sp_cc & SP_EM;
800 			m0->m_len -= sizeof (*sh);
801 			m0->m_data += sizeof (*sh);
802 			len -= sizeof (*sh);
803 		}
804 		len += sizeof(*si);
805 		if ((cb->s_flags2 & SF_NEWCALL) && recordp) {
806 			si->si_cc  |= SP_EM;
807 			spp_newchecks[8]++;
808 		}
809 		if (cb->s_oobflags & SF_SOOB) {
810 			/*
811 			 * Per jqj@cornell:
812 			 * make sure OB packets convey exactly 1 byte.
813 			 * If the packet is 1 byte or larger, we
814 			 * have already guaranted there to be at least
815 			 * one garbage byte for the checksum, and
816 			 * extra bytes shouldn't hurt!
817 			 */
818 			if (len > sizeof(*si)) {
819 				si->si_cc |= SP_OB;
820 				len = (1 + sizeof(*si));
821 			}
822 		}
823 		si->si_len = htons((u_short)len);
824 		m->m_pkthdr.len = ((len - 1) | 1) + 1;
825 		/*
826 		 * queue stuff up for output
827 		 */
828 		sbappendrecord(sb, m);
829 		cb->s_seq++;
830 	}
831 #ifdef notdef
832 	idle = (cb->s_smax == (cb->s_rack - 1));
833 #endif
834 again:
835 	sendalot = 0;
836 	off = cb->s_snxt - cb->s_rack;
837 	win = min(cb->s_swnd, (cb->s_cwnd/CUNIT));
838 
839 	/*
840 	 * If in persist timeout with window of 0, send a probe.
841 	 * Otherwise, if window is small but nonzero
842 	 * and timer expired, send what we can and go into
843 	 * transmit state.
844 	 */
845 	if (cb->s_force == 1 + SPPT_PERSIST) {
846 		if (win != 0) {
847 			cb->s_timer[SPPT_PERSIST] = 0;
848 			cb->s_rxtshift = 0;
849 		}
850 	}
851 	span = cb->s_seq - cb->s_rack;
852 	len = min(span, win) - off;
853 
854 	if (len < 0) {
855 		/*
856 		 * Window shrank after we went into it.
857 		 * If window shrank to 0, cancel pending
858 		 * restransmission and pull s_snxt back
859 		 * to (closed) window.  We will enter persist
860 		 * state below.  If the widndow didn't close completely,
861 		 * just wait for an ACK.
862 		 */
863 		len = 0;
864 		if (win == 0) {
865 			cb->s_timer[SPPT_REXMT] = 0;
866 			cb->s_snxt = cb->s_rack;
867 		}
868 	}
869 	if (len > 1)
870 		sendalot = 1;
871 	rcv_win = sbspace(&so->so_rcv);
872 
873 	/*
874 	 * Send if we owe peer an ACK.
875 	 */
876 	if (cb->s_oobflags & SF_SOOB) {
877 		/*
878 		 * must transmit this out of band packet
879 		 */
880 		cb->s_oobflags &= ~ SF_SOOB;
881 		sendalot = 1;
882 		sppstat.spps_sndurg++;
883 		goto found;
884 	}
885 	if (cb->s_flags & SF_ACKNOW)
886 		goto send;
887 	if (cb->s_state < TCPS_ESTABLISHED)
888 		goto send;
889 	/*
890 	 * Silly window can't happen in spp.
891 	 * Code from tcp deleted.
892 	 */
893 	if (len)
894 		goto send;
895 	/*
896 	 * Compare available window to amount of window
897 	 * known to peer (as advertised window less
898 	 * next expected input.)  If the difference is at least two
899 	 * packets or at least 35% of the mximum possible window,
900 	 * then want to send a window update to peer.
901 	 */
902 	if (rcv_win > 0) {
903 		u_short delta =  1 + cb->s_alo - cb->s_ack;
904 		int adv = rcv_win - (delta * cb->s_mtu);
905 
906 		if ((so->so_rcv.sb_cc == 0 && adv >= (2 * cb->s_mtu)) ||
907 		    (100 * adv / so->so_rcv.sb_hiwat >= 35)) {
908 			sppstat.spps_sndwinup++;
909 			cb->s_flags |= SF_ACKNOW;
910 			goto send;
911 		}
912 
913 	}
914 	/*
915 	 * Many comments from tcp_output.c are appropriate here
916 	 * including . . .
917 	 * If send window is too small, there is data to transmit, and no
918 	 * retransmit or persist is pending, then go to persist state.
919 	 * If nothing happens soon, send when timer expires:
920 	 * if window is nonzero, transmit what we can,
921 	 * otherwise send a probe.
922 	 */
923 	if (so->so_snd.sb_cc && cb->s_timer[SPPT_REXMT] == 0 &&
924 		cb->s_timer[SPPT_PERSIST] == 0) {
925 			cb->s_rxtshift = 0;
926 			spp_setpersist(cb);
927 	}
928 	/*
929 	 * No reason to send a packet, just return.
930 	 */
931 	cb->s_outx = 1;
932 	return (0);
933 
934 send:
935 	/*
936 	 * Find requested packet.
937 	 */
938 	si = 0;
939 	if (len > 0) {
940 		cb->s_want = cb->s_snxt;
941 		for (m = sb->sb_mb; m; m = m->m_act) {
942 			si = mtod(m, struct spidp *);
943 			if (SSEQ_LEQ(cb->s_snxt, si->si_seq))
944 				break;
945 		}
946 	found:
947 		if (si) {
948 			if (si->si_seq == cb->s_snxt)
949 					cb->s_snxt++;
950 				else
951 					sppstat.spps_sndvoid++, si = 0;
952 		}
953 	}
954 	/*
955 	 * update window
956 	 */
957 	if (rcv_win < 0)
958 		rcv_win = 0;
959 	alo = cb->s_ack - 1 + (rcv_win / ((short)cb->s_mtu));
960 	if (SSEQ_LT(alo, cb->s_alo))
961 		alo = cb->s_alo;
962 
963 	if (si) {
964 		/*
965 		 * must make a copy of this packet for
966 		 * idp_output to monkey with
967 		 */
968 		m = m_copy(dtom(si), 0, (int)M_COPYALL);
969 		if (m == NULL) {
970 			return (ENOBUFS);
971 		}
972 		si = mtod(m, struct spidp *);
973 		if (SSEQ_LT(si->si_seq, cb->s_smax))
974 			sppstat.spps_sndrexmitpack++;
975 		else
976 			sppstat.spps_sndpack++;
977 	} else if (cb->s_force || cb->s_flags & SF_ACKNOW) {
978 		/*
979 		 * Must send an acknowledgement or a probe
980 		 */
981 		if (cb->s_force)
982 			sppstat.spps_sndprobe++;
983 		if (cb->s_flags & SF_ACKNOW)
984 			sppstat.spps_sndacks++;
985 		m = m_gethdr(M_DONTWAIT, MT_HEADER);
986 		if (m == 0)
987 			return (ENOBUFS);
988 		/*
989 		 * Fill in mbuf with extended SP header
990 		 * and addresses and length put into network format.
991 		 */
992 		MH_ALIGN(m, sizeof (struct spidp));
993 		m->m_len = sizeof (*si);
994 		m->m_pkthdr.len = sizeof (*si);
995 		si = mtod(m, struct spidp *);
996 		si->si_i = *cb->s_idp;
997 		si->si_s = cb->s_shdr;
998 		si->si_seq = cb->s_smax + 1;
999 		si->si_len = htons(sizeof (*si));
1000 		si->si_cc |= SP_SP;
1001 	} else {
1002 		cb->s_outx = 3;
1003 		if (so->so_options & SO_DEBUG || traceallspps)
1004 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
1005 		return (0);
1006 	}
1007 	/*
1008 	 * Stuff checksum and output datagram.
1009 	 */
1010 	if ((si->si_cc & SP_SP) == 0) {
1011 		if (cb->s_force != (1 + SPPT_PERSIST) ||
1012 		    cb->s_timer[SPPT_PERSIST] == 0) {
1013 			/*
1014 			 * If this is a new packet and we are not currently
1015 			 * timing anything, time this one.
1016 			 */
1017 			if (SSEQ_LT(cb->s_smax, si->si_seq)) {
1018 				cb->s_smax = si->si_seq;
1019 				if (cb->s_rtt == 0) {
1020 					sppstat.spps_segstimed++;
1021 					cb->s_rtseq = si->si_seq;
1022 					cb->s_rtt = 1;
1023 				}
1024 			}
1025 			/*
1026 			 * Set rexmt timer if not currently set,
1027 			 * Initial value for retransmit timer is smoothed
1028 			 * round-trip time + 2 * round-trip time variance.
1029 			 * Initialize shift counter which is used for backoff
1030 			 * of retransmit time.
1031 			 */
1032 			if (cb->s_timer[SPPT_REXMT] == 0 &&
1033 			    cb->s_snxt != cb->s_rack) {
1034 				cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
1035 				if (cb->s_timer[SPPT_PERSIST]) {
1036 					cb->s_timer[SPPT_PERSIST] = 0;
1037 					cb->s_rxtshift = 0;
1038 				}
1039 			}
1040 		} else if (SSEQ_LT(cb->s_smax, si->si_seq)) {
1041 			cb->s_smax = si->si_seq;
1042 		}
1043 	} else if (cb->s_state < TCPS_ESTABLISHED) {
1044 		if (cb->s_rtt == 0)
1045 			cb->s_rtt = 1; /* Time initial handshake */
1046 		if (cb->s_timer[SPPT_REXMT] == 0)
1047 			cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
1048 	}
1049 	{
1050 		/*
1051 		 * Do not request acks when we ack their data packets or
1052 		 * when we do a gratuitous window update.
1053 		 */
1054 		if (((si->si_cc & SP_SP) == 0) || cb->s_force)
1055 				si->si_cc |= SP_SA;
1056 		si->si_seq = htons(si->si_seq);
1057 		si->si_alo = htons(alo);
1058 		si->si_ack = htons(cb->s_ack);
1059 
1060 		if (idpcksum) {
1061 			si->si_sum = 0;
1062 			len = ntohs(si->si_len);
1063 			if (len & 1)
1064 				len++;
1065 			si->si_sum = ns_cksum(m, len);
1066 		} else
1067 			si->si_sum = 0xffff;
1068 
1069 		cb->s_outx = 4;
1070 		if (so->so_options & SO_DEBUG || traceallspps)
1071 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
1072 
1073 		if (so->so_options & SO_DONTROUTE)
1074 			error = ns_output(m, (struct route *)0, NS_ROUTETOIF);
1075 		else
1076 			error = ns_output(m, &cb->s_nspcb->nsp_route, 0);
1077 	}
1078 	if (error) {
1079 		return (error);
1080 	}
1081 	sppstat.spps_sndtotal++;
1082 	/*
1083 	 * Data sent (as far as we can tell).
1084 	 * If this advertises a larger window than any other segment,
1085 	 * then remember the size of the advertized window.
1086 	 * Any pending ACK has now been sent.
1087 	 */
1088 	cb->s_force = 0;
1089 	cb->s_flags &= ~(SF_ACKNOW|SF_DELACK);
1090 	if (SSEQ_GT(alo, cb->s_alo))
1091 		cb->s_alo = alo;
1092 	if (sendalot)
1093 		goto again;
1094 	cb->s_outx = 5;
1095 	return (0);
1096 }
1097 
1098 int spp_do_persist_panics = 0;
1099 
1100 spp_setpersist(cb)
1101 	register struct sppcb *cb;
1102 {
1103 	register t = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1104 	extern int spp_backoff[];
1105 
1106 	if (cb->s_timer[SPPT_REXMT] && spp_do_persist_panics)
1107 		panic("spp_output REXMT");
1108 	/*
1109 	 * Start/restart persistance timer.
1110 	 */
1111 	SPPT_RANGESET(cb->s_timer[SPPT_PERSIST],
1112 	    t*spp_backoff[cb->s_rxtshift],
1113 	    SPPTV_PERSMIN, SPPTV_PERSMAX);
1114 	if (cb->s_rxtshift < SPP_MAXRXTSHIFT)
1115 		cb->s_rxtshift++;
1116 }
1117 /*ARGSUSED*/
1118 spp_ctloutput(req, so, level, name, value)
1119 	int req;
1120 	struct socket *so;
1121 	int name;
1122 	struct mbuf **value;
1123 {
1124 	register struct mbuf *m;
1125 	struct nspcb *nsp = sotonspcb(so);
1126 	register struct sppcb *cb;
1127 	int mask, error = 0;
1128 
1129 	if (level != NSPROTO_SPP) {
1130 		/* This will have to be changed when we do more general
1131 		   stacking of protocols */
1132 		return (idp_ctloutput(req, so, level, name, value));
1133 	}
1134 	if (nsp == NULL) {
1135 		error = EINVAL;
1136 		goto release;
1137 	} else
1138 		cb = nstosppcb(nsp);
1139 
1140 	switch (req) {
1141 
1142 	case PRCO_GETOPT:
1143 		if (value == NULL)
1144 			return (EINVAL);
1145 		m = m_get(M_DONTWAIT, MT_DATA);
1146 		if (m == NULL)
1147 			return (ENOBUFS);
1148 		switch (name) {
1149 
1150 		case SO_HEADERS_ON_INPUT:
1151 			mask = SF_HI;
1152 			goto get_flags;
1153 
1154 		case SO_HEADERS_ON_OUTPUT:
1155 			mask = SF_HO;
1156 		get_flags:
1157 			m->m_len = sizeof(short);
1158 			*mtod(m, short *) = cb->s_flags & mask;
1159 			break;
1160 
1161 		case SO_MTU:
1162 			m->m_len = sizeof(u_short);
1163 			*mtod(m, short *) = cb->s_mtu;
1164 			break;
1165 
1166 		case SO_LAST_HEADER:
1167 			m->m_len = sizeof(struct sphdr);
1168 			*mtod(m, struct sphdr *) = cb->s_rhdr;
1169 			break;
1170 
1171 		case SO_DEFAULT_HEADERS:
1172 			m->m_len = sizeof(struct spidp);
1173 			*mtod(m, struct sphdr *) = cb->s_shdr;
1174 			break;
1175 
1176 		default:
1177 			error = EINVAL;
1178 		}
1179 		*value = m;
1180 		break;
1181 
1182 	case PRCO_SETOPT:
1183 		if (value == 0 || *value == 0) {
1184 			error = EINVAL;
1185 			break;
1186 		}
1187 		switch (name) {
1188 			int *ok;
1189 
1190 		case SO_HEADERS_ON_INPUT:
1191 			mask = SF_HI;
1192 			goto set_head;
1193 
1194 		case SO_HEADERS_ON_OUTPUT:
1195 			mask = SF_HO;
1196 		set_head:
1197 			if (cb->s_flags & SF_PI) {
1198 				ok = mtod(*value, int *);
1199 				if (*ok)
1200 					cb->s_flags |= mask;
1201 				else
1202 					cb->s_flags &= ~mask;
1203 			} else error = EINVAL;
1204 			break;
1205 
1206 		case SO_MTU:
1207 			cb->s_mtu = *(mtod(*value, u_short *));
1208 			break;
1209 
1210 #ifdef SF_NEWCALL
1211 		case SO_NEWCALL:
1212 			ok = mtod(*value, int *);
1213 			if (*ok) {
1214 				cb->s_flags2 |= SF_NEWCALL;
1215 				spp_newchecks[5]++;
1216 			} else {
1217 				cb->s_flags2 &= ~SF_NEWCALL;
1218 				spp_newchecks[6]++;
1219 			}
1220 			break;
1221 #endif
1222 
1223 		case SO_DEFAULT_HEADERS:
1224 			{
1225 				register struct sphdr *sp
1226 						= mtod(*value, struct sphdr *);
1227 				cb->s_dt = sp->sp_dt;
1228 				cb->s_cc = sp->sp_cc & SP_EM;
1229 			}
1230 			break;
1231 
1232 		default:
1233 			error = EINVAL;
1234 		}
1235 		m_freem(*value);
1236 		break;
1237 	}
1238 	release:
1239 		return (error);
1240 }
1241 
1242 /*ARGSUSED*/
1243 spp_usrreq(so, req, m, nam, rights, controlp)
1244 	struct socket *so;
1245 	int req;
1246 	struct mbuf *m, *nam, *rights, *controlp;
1247 {
1248 	struct nspcb *nsp = sotonspcb(so);
1249 	register struct sppcb *cb;
1250 	int s = splnet();
1251 	int error = 0, ostate;
1252 	struct mbuf *mm;
1253 	register struct sockbuf *sb;
1254 
1255 	if (req == PRU_CONTROL)
1256                 return (ns_control(so, (int)m, (caddr_t)nam,
1257 			(struct ifnet *)rights));
1258 	if (rights && rights->m_len) {
1259 		error = EINVAL;
1260 		goto release;
1261 	}
1262 	if (nsp == NULL) {
1263 		if (req != PRU_ATTACH) {
1264 			error = EINVAL;
1265 			goto release;
1266 		}
1267 	} else
1268 		cb = nstosppcb(nsp);
1269 
1270 	ostate = cb ? cb->s_state : 0;
1271 
1272 	switch (req) {
1273 
1274 	case PRU_ATTACH:
1275 		if (nsp != NULL) {
1276 			error = EISCONN;
1277 			break;
1278 		}
1279 		error = ns_pcballoc(so, &nspcb);
1280 		if (error)
1281 			break;
1282 		if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
1283 			error = soreserve(so, (u_long) 3072, (u_long) 3072);
1284 			if (error)
1285 				break;
1286 		}
1287 		nsp = sotonspcb(so);
1288 
1289 		mm = m_getclr(M_DONTWAIT, MT_PCB);
1290 		sb = &so->so_snd;
1291 
1292 		if (mm == NULL) {
1293 			error = ENOBUFS;
1294 			break;
1295 		}
1296 		cb = mtod(mm, struct sppcb *);
1297 		mm = m_getclr(M_DONTWAIT, MT_HEADER);
1298 		if (mm == NULL) {
1299 			(void) m_free(dtom(m));
1300 			error = ENOBUFS;
1301 			break;
1302 		}
1303 		cb->s_idp = mtod(mm, struct idp *);
1304 		cb->s_state = TCPS_LISTEN;
1305 		cb->s_smax = -1;
1306 		cb->s_swl1 = -1;
1307 		cb->s_q.si_next = cb->s_q.si_prev = &cb->s_q;
1308 		cb->s_nspcb = nsp;
1309 		cb->s_mtu = 576 - sizeof (struct spidp);
1310 		cb->s_cwnd = sbspace(sb) * CUNIT / cb->s_mtu;
1311 		cb->s_ssthresh = cb->s_cwnd;
1312 		cb->s_cwmx = sbspace(sb) * CUNIT /
1313 				(2 * sizeof (struct spidp));
1314 		/* Above is recomputed when connecting to account
1315 		   for changed buffering or mtu's */
1316 		cb->s_rtt = SPPTV_SRTTBASE;
1317 		cb->s_rttvar = SPPTV_SRTTDFLT << 2;
1318 		SPPT_RANGESET(cb->s_rxtcur,
1319 		    ((SPPTV_SRTTBASE >> 2) + (SPPTV_SRTTDFLT << 2)) >> 1,
1320 		    SPPTV_MIN, SPPTV_REXMTMAX);
1321 		nsp->nsp_pcb = (caddr_t) cb;
1322 		break;
1323 
1324 	case PRU_DETACH:
1325 		if (nsp == NULL) {
1326 			error = ENOTCONN;
1327 			break;
1328 		}
1329 		if (cb->s_state > TCPS_LISTEN)
1330 			cb = spp_disconnect(cb);
1331 		else
1332 			cb = spp_close(cb);
1333 		break;
1334 
1335 	case PRU_BIND:
1336 		error = ns_pcbbind(nsp, nam);
1337 		break;
1338 
1339 	case PRU_LISTEN:
1340 		if (nsp->nsp_lport == 0)
1341 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1342 		if (error == 0)
1343 			cb->s_state = TCPS_LISTEN;
1344 		break;
1345 
1346 	/*
1347 	 * Initiate connection to peer.
1348 	 * Enter SYN_SENT state, and mark socket as connecting.
1349 	 * Start keep-alive timer, setup prototype header,
1350 	 * Send initial system packet requesting connection.
1351 	 */
1352 	case PRU_CONNECT:
1353 		if (nsp->nsp_lport == 0) {
1354 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1355 			if (error)
1356 				break;
1357 		}
1358 		error = ns_pcbconnect(nsp, nam);
1359 		if (error)
1360 			break;
1361 		soisconnecting(so);
1362 		sppstat.spps_connattempt++;
1363 		cb->s_state = TCPS_SYN_SENT;
1364 		cb->s_did = 0;
1365 		spp_template(cb);
1366 		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
1367 		cb->s_force = 1 + SPPTV_KEEP;
1368 		/*
1369 		 * Other party is required to respond to
1370 		 * the port I send from, but he is not
1371 		 * required to answer from where I am sending to,
1372 		 * so allow wildcarding.
1373 		 * original port I am sending to is still saved in
1374 		 * cb->s_dport.
1375 		 */
1376 		nsp->nsp_fport = 0;
1377 		error = spp_output(cb, (struct mbuf *) 0);
1378 		break;
1379 
1380 	case PRU_CONNECT2:
1381 		error = EOPNOTSUPP;
1382 		break;
1383 
1384 	/*
1385 	 * We may decide later to implement connection closing
1386 	 * handshaking at the spp level optionally.
1387 	 * here is the hook to do it:
1388 	 */
1389 	case PRU_DISCONNECT:
1390 		cb = spp_disconnect(cb);
1391 		break;
1392 
1393 	/*
1394 	 * Accept a connection.  Essentially all the work is
1395 	 * done at higher levels; just return the address
1396 	 * of the peer, storing through addr.
1397 	 */
1398 	case PRU_ACCEPT: {
1399 		struct sockaddr_ns *sns = mtod(nam, struct sockaddr_ns *);
1400 
1401 		nam->m_len = sizeof (struct sockaddr_ns);
1402 		sns->sns_family = AF_NS;
1403 		sns->sns_addr = nsp->nsp_faddr;
1404 		break;
1405 		}
1406 
1407 	case PRU_SHUTDOWN:
1408 		socantsendmore(so);
1409 		cb = spp_usrclosed(cb);
1410 		if (cb)
1411 			error = spp_output(cb, (struct mbuf *) 0);
1412 		break;
1413 
1414 	/*
1415 	 * After a receive, possibly send acknowledgment
1416 	 * updating allocation.
1417 	 */
1418 	case PRU_RCVD:
1419 		cb->s_flags |= SF_RVD;
1420 		(void) spp_output(cb, (struct mbuf *) 0);
1421 		cb->s_flags &= ~SF_RVD;
1422 		break;
1423 
1424 	case PRU_ABORT:
1425 		(void) spp_drop(cb, ECONNABORTED);
1426 		break;
1427 
1428 	case PRU_SENSE:
1429 	case PRU_CONTROL:
1430 		m = NULL;
1431 		error = EOPNOTSUPP;
1432 		break;
1433 
1434 	case PRU_RCVOOB:
1435 		if ((cb->s_oobflags & SF_IOOB) || so->so_oobmark ||
1436 		    (so->so_state & SS_RCVATMARK)) {
1437 			m->m_len = 1;
1438 			*mtod(m, caddr_t) = cb->s_iobc;
1439 			break;
1440 		}
1441 		error = EINVAL;
1442 		break;
1443 
1444 	case PRU_SENDOOB:
1445 		if (sbspace(&so->so_snd) < -512) {
1446 			error = ENOBUFS;
1447 			break;
1448 		}
1449 		cb->s_oobflags |= SF_SOOB;
1450 		/* fall into */
1451 	case PRU_SEND:
1452 		if (controlp) {
1453 			u_short *p = mtod(controlp, u_short *);
1454 			spp_newchecks[2]++;
1455 			if ((p[0] == 5) && p[1] == 1) { /* XXXX, for testing */
1456 				cb->s_shdr.sp_dt = *(u_char *)(&p[2]);
1457 				spp_newchecks[3]++;
1458 			}
1459 		}
1460 		error = spp_output(cb, m);
1461 		m = NULL;
1462 		break;
1463 
1464 	case PRU_SOCKADDR:
1465 		ns_setsockaddr(nsp, nam);
1466 		break;
1467 
1468 	case PRU_PEERADDR:
1469 		ns_setpeeraddr(nsp, nam);
1470 		break;
1471 
1472 	case PRU_SLOWTIMO:
1473 		cb = spp_timers(cb, (int)nam);
1474 		req |= ((int)nam) << 8;
1475 		break;
1476 
1477 	case PRU_FASTTIMO:
1478 	case PRU_PROTORCV:
1479 	case PRU_PROTOSEND:
1480 		error =  EOPNOTSUPP;
1481 		break;
1482 
1483 	default:
1484 		panic("sp_usrreq");
1485 	}
1486 	if (cb && (so->so_options & SO_DEBUG || traceallspps))
1487 		spp_trace(SA_USER, (u_char)ostate, cb, (struct spidp *)0, req);
1488 release:
1489 	if (m != NULL)
1490 		m_freem(m);
1491 	splx(s);
1492 	return (error);
1493 }
1494 
1495 spp_usrreq_sp(so, req, m, nam, rights, controlp)
1496 	struct socket *so;
1497 	int req;
1498 	struct mbuf *m, *nam, *rights, *controlp;
1499 {
1500 	int error = spp_usrreq(so, req, m, nam, rights, controlp);
1501 
1502 	if (req == PRU_ATTACH && error == 0) {
1503 		struct nspcb *nsp = sotonspcb(so);
1504 		((struct sppcb *)nsp->nsp_pcb)->s_flags |=
1505 					(SF_HI | SF_HO | SF_PI);
1506 	}
1507 	return (error);
1508 }
1509 
1510 /*
1511  * Create template to be used to send spp packets on a connection.
1512  * Called after host entry created, fills
1513  * in a skeletal spp header (choosing connection id),
1514  * minimizing the amount of work necessary when the connection is used.
1515  */
1516 spp_template(cb)
1517 	register struct sppcb *cb;
1518 {
1519 	register struct nspcb *nsp = cb->s_nspcb;
1520 	register struct idp *idp = cb->s_idp;
1521 	register struct sockbuf *sb = &(nsp->nsp_socket->so_snd);
1522 
1523 	idp->idp_pt = NSPROTO_SPP;
1524 	idp->idp_sna = nsp->nsp_laddr;
1525 	idp->idp_dna = nsp->nsp_faddr;
1526 	cb->s_sid = htons(spp_iss);
1527 	spp_iss += SPP_ISSINCR/2;
1528 	cb->s_alo = 1;
1529 	cb->s_cwnd = (sbspace(sb) * CUNIT) / cb->s_mtu;
1530 	cb->s_ssthresh = cb->s_cwnd; /* Try to expand fast to full complement
1531 					of large packets */
1532 	cb->s_cwmx = (sbspace(sb) * CUNIT) / (2 * sizeof(struct spidp));
1533 	cb->s_cwmx = max(cb->s_cwmx, cb->s_cwnd);
1534 		/* But allow for lots of little packets as well */
1535 }
1536 
1537 /*
1538  * Close a SPIP control block:
1539  *	discard spp control block itself
1540  *	discard ns protocol control block
1541  *	wake up any sleepers
1542  */
1543 struct sppcb *
1544 spp_close(cb)
1545 	register struct sppcb *cb;
1546 {
1547 	register struct spidp_q *s;
1548 	struct nspcb *nsp = cb->s_nspcb;
1549 	struct socket *so = nsp->nsp_socket;
1550 	register struct mbuf *m;
1551 
1552 	s = cb->s_q.si_next;
1553 	while (s != &(cb->s_q)) {
1554 		s = s->si_next;
1555 		m = dtom(s->si_prev);
1556 		remque(s->si_prev);
1557 		m_freem(m);
1558 	}
1559 	(void) m_free(dtom(cb->s_idp));
1560 	(void) m_free(dtom(cb));
1561 	nsp->nsp_pcb = 0;
1562 	soisdisconnected(so);
1563 	ns_pcbdetach(nsp);
1564 	sppstat.spps_closed++;
1565 	return ((struct sppcb *)0);
1566 }
1567 /*
1568  *	Someday we may do level 3 handshaking
1569  *	to close a connection or send a xerox style error.
1570  *	For now, just close.
1571  */
1572 struct sppcb *
1573 spp_usrclosed(cb)
1574 	register struct sppcb *cb;
1575 {
1576 	return (spp_close(cb));
1577 }
1578 struct sppcb *
1579 spp_disconnect(cb)
1580 	register struct sppcb *cb;
1581 {
1582 	return (spp_close(cb));
1583 }
1584 /*
1585  * Drop connection, reporting
1586  * the specified error.
1587  */
1588 struct sppcb *
1589 spp_drop(cb, errno)
1590 	register struct sppcb *cb;
1591 	int errno;
1592 {
1593 	struct socket *so = cb->s_nspcb->nsp_socket;
1594 
1595 	/*
1596 	 * someday, in the xerox world
1597 	 * we will generate error protocol packets
1598 	 * announcing that the socket has gone away.
1599 	 */
1600 	if (TCPS_HAVERCVDSYN(cb->s_state)) {
1601 		sppstat.spps_drops++;
1602 		cb->s_state = TCPS_CLOSED;
1603 		/*(void) tcp_output(cb);*/
1604 	} else
1605 		sppstat.spps_conndrops++;
1606 	so->so_error = errno;
1607 	return (spp_close(cb));
1608 }
1609 
1610 spp_abort(nsp)
1611 	struct nspcb *nsp;
1612 {
1613 
1614 	(void) spp_close((struct sppcb *)nsp->nsp_pcb);
1615 }
1616 
1617 int	spp_backoff[SPP_MAXRXTSHIFT+1] =
1618     { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
1619 /*
1620  * Fast timeout routine for processing delayed acks
1621  */
1622 spp_fasttimo()
1623 {
1624 	register struct nspcb *nsp;
1625 	register struct sppcb *cb;
1626 	int s = splnet();
1627 
1628 	nsp = nspcb.nsp_next;
1629 	if (nsp)
1630 	for (; nsp != &nspcb; nsp = nsp->nsp_next)
1631 		if ((cb = (struct sppcb *)nsp->nsp_pcb) &&
1632 		    (cb->s_flags & SF_DELACK)) {
1633 			cb->s_flags &= ~SF_DELACK;
1634 			cb->s_flags |= SF_ACKNOW;
1635 			sppstat.spps_delack++;
1636 			(void) spp_output(cb, (struct mbuf *) 0);
1637 		}
1638 	splx(s);
1639 }
1640 
1641 /*
1642  * spp protocol timeout routine called every 500 ms.
1643  * Updates the timers in all active pcb's and
1644  * causes finite state machine actions if timers expire.
1645  */
1646 spp_slowtimo()
1647 {
1648 	register struct nspcb *ip, *ipnxt;
1649 	register struct sppcb *cb;
1650 	int s = splnet();
1651 	register int i;
1652 
1653 	/*
1654 	 * Search through tcb's and update active timers.
1655 	 */
1656 	ip = nspcb.nsp_next;
1657 	if (ip == 0) {
1658 		splx(s);
1659 		return;
1660 	}
1661 	while (ip != &nspcb) {
1662 		cb = nstosppcb(ip);
1663 		ipnxt = ip->nsp_next;
1664 		if (cb == 0)
1665 			goto tpgone;
1666 		for (i = 0; i < SPPT_NTIMERS; i++) {
1667 			if (cb->s_timer[i] && --cb->s_timer[i] == 0) {
1668 				(void) spp_usrreq(cb->s_nspcb->nsp_socket,
1669 				    PRU_SLOWTIMO, (struct mbuf *)0,
1670 				    (struct mbuf *)i, (struct mbuf *)0,
1671 				    (struct mbuf *)0);
1672 				if (ipnxt->nsp_prev != ip)
1673 					goto tpgone;
1674 			}
1675 		}
1676 		cb->s_idle++;
1677 		if (cb->s_rtt)
1678 			cb->s_rtt++;
1679 tpgone:
1680 		ip = ipnxt;
1681 	}
1682 	spp_iss += SPP_ISSINCR/PR_SLOWHZ;		/* increment iss */
1683 	splx(s);
1684 }
1685 /*
1686  * SPP timer processing.
1687  */
1688 struct sppcb *
1689 spp_timers(cb, timer)
1690 	register struct sppcb *cb;
1691 	int timer;
1692 {
1693 	long rexmt;
1694 	int win;
1695 
1696 	cb->s_force = 1 + timer;
1697 	switch (timer) {
1698 
1699 	/*
1700 	 * 2 MSL timeout in shutdown went off.  TCP deletes connection
1701 	 * control block.
1702 	 */
1703 	case SPPT_2MSL:
1704 		printf("spp: SPPT_2MSL went off for no reason\n");
1705 		cb->s_timer[timer] = 0;
1706 		break;
1707 
1708 	/*
1709 	 * Retransmission timer went off.  Message has not
1710 	 * been acked within retransmit interval.  Back off
1711 	 * to a longer retransmit interval and retransmit one packet.
1712 	 */
1713 	case SPPT_REXMT:
1714 		if (++cb->s_rxtshift > SPP_MAXRXTSHIFT) {
1715 			cb->s_rxtshift = SPP_MAXRXTSHIFT;
1716 			sppstat.spps_timeoutdrop++;
1717 			cb = spp_drop(cb, ETIMEDOUT);
1718 			break;
1719 		}
1720 		sppstat.spps_rexmttimeo++;
1721 		rexmt = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1722 		rexmt *= spp_backoff[cb->s_rxtshift];
1723 		SPPT_RANGESET(cb->s_rxtcur, rexmt, SPPTV_MIN, SPPTV_REXMTMAX);
1724 		cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
1725 		/*
1726 		 * If we have backed off fairly far, our srtt
1727 		 * estimate is probably bogus.  Clobber it
1728 		 * so we'll take the next rtt measurement as our srtt;
1729 		 * move the current srtt into rttvar to keep the current
1730 		 * retransmit times until then.
1731 		 */
1732 		if (cb->s_rxtshift > SPP_MAXRXTSHIFT / 4 ) {
1733 			cb->s_rttvar += (cb->s_srtt >> 2);
1734 			cb->s_srtt = 0;
1735 		}
1736 		cb->s_snxt = cb->s_rack;
1737 		/*
1738 		 * If timing a packet, stop the timer.
1739 		 */
1740 		cb->s_rtt = 0;
1741 		/*
1742 		 * See very long discussion in tcp_timer.c about congestion
1743 		 * window and sstrhesh
1744 		 */
1745 		win = min(cb->s_swnd, (cb->s_cwnd/CUNIT)) / 2;
1746 		if (win < 2)
1747 			win = 2;
1748 		cb->s_cwnd = CUNIT;
1749 		cb->s_ssthresh = win * CUNIT;
1750 		(void) spp_output(cb, (struct mbuf *) 0);
1751 		break;
1752 
1753 	/*
1754 	 * Persistance timer into zero window.
1755 	 * Force a probe to be sent.
1756 	 */
1757 	case SPPT_PERSIST:
1758 		sppstat.spps_persisttimeo++;
1759 		spp_setpersist(cb);
1760 		(void) spp_output(cb, (struct mbuf *) 0);
1761 		break;
1762 
1763 	/*
1764 	 * Keep-alive timer went off; send something
1765 	 * or drop connection if idle for too long.
1766 	 */
1767 	case SPPT_KEEP:
1768 		sppstat.spps_keeptimeo++;
1769 		if (cb->s_state < TCPS_ESTABLISHED)
1770 			goto dropit;
1771 		if (cb->s_nspcb->nsp_socket->so_options & SO_KEEPALIVE) {
1772 		    	if (cb->s_idle >= SPPTV_MAXIDLE)
1773 				goto dropit;
1774 			sppstat.spps_keepprobe++;
1775 			(void) spp_output(cb, (struct mbuf *) 0);
1776 		} else
1777 			cb->s_idle = 0;
1778 		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
1779 		break;
1780 	dropit:
1781 		sppstat.spps_keepdrops++;
1782 		cb = spp_drop(cb, ETIMEDOUT);
1783 		break;
1784 	}
1785 	return (cb);
1786 }
1787 #ifndef lint
1788 int SppcbSize = sizeof (struct sppcb);
1789 int NspcbSize = sizeof (struct nspcb);
1790 #endif lint
1791