xref: /csrg-svn/sys/netns/spp_usrreq.c (revision 32597)
1 /*
2  * Copyright (c) 1984, 1985, 1986, 1987 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	7.3 (Berkeley) 11/05/87
7  */
8 
9 #include "param.h"
10 #include "systm.h"
11 #include "dir.h"
12 #include "user.h"
13 #include "mbuf.h"
14 #include "protosw.h"
15 #include "socket.h"
16 #include "socketvar.h"
17 #include "errno.h"
18 
19 #include "../net/if.h"
20 #include "../net/route.h"
21 #include "../netinet/tcp_fsm.h"
22 #include "../netinet/tcp_timer.h"
23 
24 #include "ns.h"
25 #include "ns_pcb.h"
26 #include "idp.h"
27 #include "idp_var.h"
28 #include "ns_error.h"
29 #include "sp.h"
30 #include "spidp.h"
31 #include "spp_var.h"
32 #include "spp_debug.h"
33 
34 /*
35  * SP protocol implementation.
36  */
37 spp_init()
38 {
39 
40 	spp_iss = 1; /* WRONG !! should fish it out of TODR */
41 }
42 struct spidp spp_savesi;
43 int traceallspps = 0;
44 extern int sppconsdebug;
45 int spp_hardnosed;
46 int spp_use_delack = 0;
47 
48 /*ARGSUSED*/
49 spp_input(m, nsp, ifp)
50 	register struct mbuf *m;
51 	register struct nspcb *nsp;
52 	struct ifnet *ifp;
53 {
54 	register struct sppcb *cb;
55 	register struct spidp *si = mtod(m, struct spidp *);
56 	register struct socket *so;
57 	short ostate;
58 	int dropsocket = 0;
59 
60 
61 	sppstat.spps_rcvtotal++;
62 	if (nsp == 0) {
63 		panic("No nspcb in spp_input\n");
64 		return;
65 	}
66 
67 	cb = nstosppcb(nsp);
68 	if (cb == 0) goto bad;
69 
70 	if (m->m_len < sizeof(*si)) {
71 		if ((m = m_pullup(m, sizeof(*si))) == 0) {
72 			sppstat.spps_rcvshort++;
73 			return;
74 		}
75 		si = mtod(m, struct spidp *);
76 	}
77 	si->si_seq = ntohs(si->si_seq);
78 	si->si_ack = ntohs(si->si_ack);
79 	si->si_alo = ntohs(si->si_alo);
80 
81 	so = nsp->nsp_socket;
82 	if (so->so_options & SO_DEBUG || traceallspps) {
83 		ostate = cb->s_state;
84 		spp_savesi = *si;
85 	}
86 	if (so->so_options & SO_ACCEPTCONN) {
87 		struct sppcb *ocb = cb;
88 		struct socket *oso = so;
89 		so = sonewconn(so);
90 		if (so == 0) {
91 			goto drop;
92 		}
93 		/*
94 		 * This is ugly, but ....
95 		 *
96 		 * Mark socket as temporary until we're
97 		 * committed to keeping it.  The code at
98 		 * ``drop'' and ``dropwithreset'' check the
99 		 * flag dropsocket to see if the temporary
100 		 * socket created here should be discarded.
101 		 * We mark the socket as discardable until
102 		 * we're committed to it below in TCPS_LISTEN.
103 		 */
104 		dropsocket++;
105 		nsp = (struct nspcb *)so->so_pcb;
106 		nsp->nsp_laddr = si->si_dna;
107 		cb = nstosppcb(nsp);
108 		cb->s_mtu = ocb->s_mtu;		/* preserve sockopts */
109 		cb->s_flags = ocb->s_flags;	/* preserve sockopts */
110 		if (so->so_snd.sb_hiwat != oso->so_snd.sb_hiwat) /*XXX*/
111 			sbreserve(&so->so_snd, oso->so_snd.sb_hiwat);
112 		if (so->so_rcv.sb_hiwat != oso->so_rcv.sb_hiwat) /*XXX*/
113 			sbreserve(&so->so_rcv, oso->so_rcv.sb_hiwat);
114 		cb->s_state = TCPS_LISTEN;
115 	}
116 
117 	/*
118 	 * Packet received on connection.
119 	 * reset idle time and keep-alive timer;
120 	 */
121 	cb->s_idle = 0;
122 	cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
123 
124 	switch (cb->s_state) {
125 
126 	case TCPS_LISTEN:{
127 		struct mbuf *am;
128 		register struct sockaddr_ns *sns;
129 		struct ns_addr laddr;
130 
131 		/*
132 		 * If somebody here was carying on a conversation
133 		 * and went away, and his pen pal thinks he can
134 		 * still talk, we get the misdirected packet.
135 		 */
136 		if (spp_hardnosed && (si->si_did != 0 || si->si_seq != 0)) {
137 			spp_istat.gonawy++;
138 			goto dropwithreset;
139 		}
140 		am = m_get(M_DONTWAIT, MT_SONAME);
141 		if (am == NULL)
142 			goto drop;
143 		am->m_len = sizeof (struct sockaddr_ns);
144 		sns = mtod(am, struct sockaddr_ns *);
145 		sns->sns_family = AF_NS;
146 		sns->sns_addr = si->si_sna;
147 		laddr = nsp->nsp_laddr;
148 		if (ns_nullhost(laddr))
149 			nsp->nsp_laddr = si->si_dna;
150 		if (ns_pcbconnect(nsp, am)) {
151 			nsp->nsp_laddr = laddr;
152 			(void) m_free(am);
153 			spp_istat.noconn++;
154 			goto drop;
155 		}
156 		(void) m_free(am);
157 		spp_template(cb);
158 		dropsocket = 0;		/* committed to socket */
159 		cb->s_did = si->si_sid;
160 		cb->s_rack = si->si_ack;
161 		cb->s_ralo = si->si_alo;
162 #define THREEWAYSHAKE
163 #ifdef THREEWAYSHAKE
164 		cb->s_state = TCPS_SYN_RECEIVED;
165 		cb->s_force = 1 + TCPT_KEEP;
166 		sppstat.spps_accepts++;
167 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
168 		}
169 		break;
170 	/*
171 	 * This state means that we have heard a response
172 	 * to our acceptance of their connection
173 	 * It is probably logically unnecessary in this
174 	 * implementation.
175 	 */
176 	 case TCPS_SYN_RECEIVED: {
177 		if (si->si_did!=cb->s_sid) {
178 			spp_istat.wrncon++;
179 			goto drop;
180 		}
181 #endif
182 		nsp->nsp_fport =  si->si_sport;
183 		cb->s_timer[TCPT_REXMT] = 0;
184 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
185 		soisconnected(so);
186 		cb->s_state = TCPS_ESTABLISHED;
187 		sppstat.spps_accepts++;
188 		}
189 		break;
190 
191 	/*
192 	 * This state means that we have gotten a response
193 	 * to our attempt to establish a connection.
194 	 * We fill in the data from the other side,
195 	 * telling us which port to respond to, instead of the well-
196 	 * known one we might have sent to in the first place.
197 	 * We also require that this is a response to our
198 	 * connection id.
199 	 */
200 	case TCPS_SYN_SENT:
201 		if (si->si_did!=cb->s_sid) {
202 			spp_istat.notme++;
203 			goto drop;
204 		}
205 		sppstat.spps_connects++;
206 		cb->s_did = si->si_sid;
207 		cb->s_rack = si->si_ack;
208 		cb->s_ralo = si->si_alo;
209 		cb->s_dport = nsp->nsp_fport =  si->si_sport;
210 		cb->s_timer[TCPT_REXMT] = 0;
211 		cb->s_flags |= SF_ACKNOW;
212 		soisconnected(so);
213 		cb->s_state = TCPS_ESTABLISHED;
214 		/* Use roundtrip time of connection request for initial rtt */
215 		if (cb->s_rtt) {
216 			cb->s_srtt = cb->s_rtt << 3;
217 			cb->s_rttvar = cb->s_rtt << 1;
218 			TCPT_RANGESET(cb->s_rxtcur,
219 			    ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1,
220 			    TCPTV_MIN, TCPTV_REXMTMAX);
221 			    cb->s_rtt = 0;
222 		}
223 	}
224 	if (so->so_options & SO_DEBUG || traceallspps)
225 		spp_trace(SA_INPUT, (u_char)ostate, cb, &spp_savesi, 0);
226 
227 	m->m_len -= sizeof (struct idp);
228 	m->m_off += sizeof (struct idp);
229 
230 	if (spp_reass(cb, si)) {
231 		m_freem(m);
232 	}
233 	if (cb->s_force || (cb->s_flags & (SF_ACKNOW|SF_WIN|SF_RXT)))
234 		(void) spp_output(cb, (struct mbuf *)0);
235 	cb->s_flags &= ~(SF_WIN|SF_RXT);
236 	return;
237 
238 dropwithreset:
239 	if (dropsocket)
240 		(void) soabort(so);
241 	si->si_seq = ntohs(si->si_seq);
242 	si->si_ack = ntohs(si->si_ack);
243 	si->si_alo = ntohs(si->si_alo);
244 	ns_error(dtom(si), NS_ERR_NOSOCK, 0);
245 	if (cb->s_nspcb->nsp_socket->so_options & SO_DEBUG || traceallspps)
246 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
247 	return;
248 
249 drop:
250 bad:
251 	if (cb == 0 || cb->s_nspcb->nsp_socket->so_options & SO_DEBUG ||
252             traceallspps)
253 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
254 	m_freem(m);
255 }
256 
257 int spprexmtthresh = 3;
258 
259 /*
260  * This is structurally similar to the tcp reassembly routine
261  * but its function is somewhat different:  It merely queues
262  * packets up, and suppresses duplicates.
263  */
264 spp_reass(cb, si)
265 register struct sppcb *cb;
266 register struct spidp *si;
267 {
268 	register struct spidp_q *q;
269 	register struct mbuf *m;
270 	register struct socket *so = cb->s_nspcb->nsp_socket;
271 	char packetp = cb->s_flags & SF_HI;
272 	int incr;
273 	char wakeup = 0;
274 
275 	if (si == SI(0))
276 		goto present;
277 	/*
278 	 * Update our news from them.
279 	 */
280 	if (si->si_cc & SP_SA)
281 		cb->s_flags |= (spp_use_delack ? SF_DELACK : SF_ACKNOW);
282 	if (SSEQ_GT(si->si_alo, cb->s_ralo))
283 		cb->s_flags |= SF_WIN;
284 	if (SSEQ_LEQ(si->si_ack, cb->s_rack)) {
285 		if ((si->si_cc & SP_SP) && cb->s_rack != cb->s_smax) {
286 			sppstat.spps_rcvdupack++;
287 			/*
288 			 * If this is a completely duplicate ack
289 			 * and other conditions hold, we assume
290 			 * a packet has been dropped and retransmit
291 			 * it exactly as in tcp_input().
292 			 */
293 			if (si->si_ack != cb->s_rack ||
294 			    si->si_alo != cb->s_ralo)
295 				cb->s_dupacks = 0;
296 			else if (++cb->s_dupacks == spprexmtthresh) {
297 				u_short onxt = cb->s_snxt;
298 				int cwnd = cb->s_cwnd;
299 
300 				cb->s_snxt = si->si_ack;
301 				cb->s_cwnd = CUNIT;
302 				cb->s_force = 1 + TCPT_REXMT;
303 				(void) spp_output(cb, 0);
304 				cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
305 				cb->s_rtt = 0;
306 				if (cwnd >= 4 * CUNIT)
307 					cb->s_cwnd = cwnd / 2;
308 				if (SSEQ_GT(onxt, cb->s_snxt))
309 					cb->s_snxt = onxt;
310 				return (1);
311 			}
312 		} else
313 			cb->s_dupacks = 0;
314 		goto update_window;
315 	}
316 	cb->s_dupacks = 0;
317 	/*
318 	 * If our correspondent acknowledges data we haven't sent
319 	 * TCP would drop the packet after acking.  We'll be a little
320 	 * more permissive
321 	 */
322 	if (SSEQ_GT(si->si_ack, (cb->s_smax + 1))) {
323 		sppstat.spps_rcvacktoomuch++;
324 		si->si_ack = cb->s_smax + 1;
325 	}
326 	sppstat.spps_rcvackpack++;
327 	/*
328 	 * If transmit timer is running and timed sequence
329 	 * number was acked, update smoothed round trip time.
330 	 * See discussion of algorithm in tcp_input.c
331 	 */
332 	if (cb->s_rtt && SSEQ_GT(si->si_ack, cb->s_rtseq)) {
333 		sppstat.spps_rttupdated++;
334 		if (cb->s_srtt != 0) {
335 			register short delta;
336 			delta = cb->s_rtt - (cb->s_srtt >> 3);
337 			if ((cb->s_srtt += delta) <= 0)
338 				cb->s_srtt = 1;
339 			if (delta < 0)
340 				delta = -delta;
341 			delta -= (cb->s_rttvar >> 2);
342 			if ((cb->s_rttvar += delta) <= 0)
343 				cb->s_rttvar = 1;
344 		} else {
345 			/*
346 			 * No rtt measurement yet
347 			 */
348 			cb->s_srtt = cb->s_rtt << 3;
349 			cb->s_rttvar = cb->s_rtt << 1;
350 		}
351 		cb->s_rtt = 0;
352 		cb->s_rxtshift = 0;
353 		TCPT_RANGESET(cb->s_rxtcur,
354 			((cb->s_srtt >> 2) + cb->s_rttvar) >> 1,
355 			TCPTV_MIN, TCPTV_REXMTMAX);
356 	}
357 	/*
358 	 * If all outstanding data is acked, stop retransmit
359 	 * timer and remember to restart (more output or persist).
360 	 * If there is more data to be acked, restart retransmit
361 	 * timer, using current (possibly backed-off) value;
362 	 */
363 	if (si->si_ack == cb->s_smax + 1) {
364 		cb->s_timer[TCPT_REXMT] = 0;
365 		cb->s_flags |= SF_RXT;
366 	} else if (cb->s_timer[TCPT_PERSIST] == 0)
367 		cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
368 	/*
369 	 * When new data is acked, open the congestion window.
370 	 * If the window gives us less than ssthresh packets
371 	 * in flight, open exponentially (maxseg at a time).
372 	 * Otherwise open linearly (maxseg^2 / cwnd at a time).
373 	 */
374 	incr = CUNIT;
375 	if (cb->s_cwnd > cb->s_ssthresh)
376 		incr = MAX(incr * incr / cb->s_cwnd, 1);
377 	cb->s_cwnd = MIN(cb->s_cwnd + incr, cb->s_cwmx);
378 	/*
379 	 * Trim Acked data from output queue.
380 	 */
381 	for (m = so->so_snd.sb_mb; m; m = m->m_act) {
382 		if (SSEQ_LT((mtod(m, struct spidp *))->si_seq, si->si_ack))
383 			sbdroprecord(&so->so_snd);
384 		else
385 			break;
386 	}
387 	if ((so->so_snd.sb_flags & SB_WAIT) || so->so_snd.sb_sel)
388 		 sowwakeup(so);
389 	cb->s_rack = si->si_ack;
390 update_window:
391 	if (SSEQ_LT(cb->s_snxt, cb->s_rack))
392 		cb->s_snxt = cb->s_rack;
393 	if (SSEQ_LT(cb->s_swl1, si->si_seq) || cb->s_swl1 == si->si_seq &&
394 	    (SSEQ_LT(cb->s_swl2, si->si_ack) ||
395 	     cb->s_swl2 == si->si_ack && SSEQ_LT(cb->s_ralo, si->si_alo))) {
396 		/* keep track of pure window updates */
397 		if ((si->si_cc & SP_SP) && cb->s_swl2 == si->si_ack
398 		    && SSEQ_LT(cb->s_ralo, si->si_alo)) {
399 			sppstat.spps_rcvwinupd++;
400 			sppstat.spps_rcvdupack--;
401 		}
402 		cb->s_ralo = si->si_alo;
403 		cb->s_swl1 = si->si_seq;
404 		cb->s_swl2 = si->si_ack;
405 		cb->s_swnd = (1 + si->si_alo - si->si_ack);
406 		if (cb->s_swnd > cb->s_smxw)
407 			cb->s_smxw = cb->s_swnd;
408 		cb->s_flags |= SF_WIN;
409 	}
410 	/*
411 	 * If this packet number is higher than that which
412 	 * we have allocated refuse it, unless urgent
413 	 */
414 	if (SSEQ_GT(si->si_seq, cb->s_alo)) {
415 		if (si->si_cc & SP_SP) {
416 			sppstat.spps_rcvwinprobe++;
417 			return (1);
418 		} else
419 			sppstat.spps_rcvpackafterwin++;
420 		if (si->si_cc & SP_OB) {
421 			if (SSEQ_GT(si->si_seq, cb->s_alo + 60)) {
422 				ns_error(dtom(si), NS_ERR_FULLUP, 0);
423 				return (0);
424 			} /* else queue this packet; */
425 		} else {
426 			/*register struct socket *so = cb->s_nspcb->nsp_socket;
427 			if (so->so_state && SS_NOFDREF) {
428 				ns_error(dtom(si), NS_ERR_NOSOCK, 0);
429 				(void)spp_close(cb);
430 			} else
431 				       would crash system*/
432 			spp_istat.notyet++;
433 			ns_error(dtom(si), NS_ERR_FULLUP, 0);
434 			return (0);
435 		}
436 	}
437 	/*
438 	 * If this is a system packet, we don't need to
439 	 * queue it up, and won't update acknowledge #
440 	 */
441 	if (si->si_cc & SP_SP) {
442 		return (1);
443 	}
444 	/*
445 	 * We have already seen this packet, so drop.
446 	 */
447 	if (SSEQ_LT(si->si_seq, cb->s_ack)) {
448 		spp_istat.bdreas++;
449 		sppstat.spps_rcvduppack++;
450 		if (si->si_seq == cb->s_ack - 1)
451 			spp_istat.lstdup++;
452 		return (1);
453 	}
454 	/*
455 	 * Loop through all packets queued up to insert in
456 	 * appropriate sequence.
457 	 */
458 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
459 		if (si->si_seq == SI(q)->si_seq) {
460 			sppstat.spps_rcvduppack++;
461 			return (1);
462 		}
463 		if (SSEQ_LT(si->si_seq, SI(q)->si_seq)) {
464 			sppstat.spps_rcvoopack++;
465 			break;
466 		}
467 	}
468 	insque(si, q->si_prev);
469 	/*
470 	 * If this packet is urgent, inform process
471 	 */
472 	if (si->si_cc & SP_OB) {
473 		cb->s_iobc = ((char *)si)[1 + sizeof(*si)];
474 		sohasoutofband(so);
475 		cb->s_oobflags |= SF_IOOB;
476 	}
477 present:
478 #define SPINC sizeof(struct sphdr)
479 	/*
480 	 * Loop through all packets queued up to update acknowledge
481 	 * number, and present all acknowledged data to user;
482 	 * If in packet interface mode, show packet headers.
483 	 */
484 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
485 		  if (SI(q)->si_seq == cb->s_ack) {
486 			cb->s_ack++;
487 			m = dtom(q);
488 			if (SI(q)->si_cc & SP_OB) {
489 				cb->s_oobflags &= ~SF_IOOB;
490 				if (so->so_rcv.sb_cc)
491 					so->so_oobmark = so->so_rcv.sb_cc;
492 				else
493 					so->so_state |= SS_RCVATMARK;
494 			}
495 			q = q->si_prev;
496 			remque(q->si_next);
497 			wakeup = 1;
498 			sppstat.spps_rcvpack++;
499 			if (packetp) {
500 				sbappendrecord(&so->so_rcv, m);
501 			} else {
502 				cb->s_rhdr = *mtod(m, struct sphdr *);
503 				m->m_off += SPINC;
504 				m->m_len -= SPINC;
505 				sbappend(&so->so_rcv, m);
506 			}
507 		  } else
508 			break;
509 	}
510 	if (wakeup) sorwakeup(so);
511 	return (0);
512 }
513 
514 spp_ctlinput(cmd, arg)
515 	int cmd;
516 	caddr_t arg;
517 {
518 	struct ns_addr *na;
519 	extern u_char nsctlerrmap[];
520 	extern spp_abort(), spp_quench();
521 	extern struct nspcb *idp_drop();
522 	struct ns_errp *errp;
523 	struct nspcb *nsp;
524 	struct sockaddr_ns *sns;
525 	int type;
526 
527 	if (cmd < 0 || cmd > PRC_NCMDS)
528 		return;
529 	type = NS_ERR_UNREACH_HOST;
530 
531 	switch (cmd) {
532 
533 	case PRC_ROUTEDEAD:
534 		return;
535 
536 	case PRC_IFDOWN:
537 	case PRC_HOSTDEAD:
538 	case PRC_HOSTUNREACH:
539 		sns = (struct sockaddr_ns *)arg;
540 		if (sns->sns_family != AF_NS)
541 			return;
542 		na = &sns->sns_addr;
543 		break;
544 
545 	default:
546 		errp = (struct ns_errp *)arg;
547 		na = &errp->ns_err_idp.idp_dna;
548 		type = errp->ns_err_num;
549 		type = ntohs((u_short)type);
550 	}
551 	switch (type) {
552 
553 	case NS_ERR_UNREACH_HOST:
554 		ns_pcbnotify(na, (int)nsctlerrmap[cmd], spp_abort, (long) 0);
555 		break;
556 
557 	case NS_ERR_TOO_BIG:
558 	case NS_ERR_NOSOCK:
559 		nsp = ns_pcblookup(na, errp->ns_err_idp.idp_sna.x_port,
560 			NS_WILDCARD);
561 		if (nsp) {
562 			if(nsp->nsp_pcb)
563 				(void) spp_drop((struct sppcb *)nsp->nsp_pcb,
564 						(int)nsctlerrmap[cmd]);
565 			else
566 				(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
567 		}
568 		break;
569 
570 	case NS_ERR_FULLUP:
571 		ns_pcbnotify(na, 0, spp_quench, (long) 0);
572 	}
573 }
574 /*
575  * When a source quench is received, close congestion window
576  * to one packet.  We will gradually open it again as we proceed.
577  */
578 spp_quench(nsp)
579 	struct nspcb *nsp;
580 {
581 	struct sppcb *cb = nstosppcb(nsp);
582 
583 	if (cb)
584 		cb->s_cwnd = CUNIT;
585 }
586 
587 #ifdef notdef
588 int
589 spp_fixmtu(nsp)
590 register struct nspcb *nsp;
591 {
592 	register struct sppcb *cb = (struct sppcb *)(nsp->nsp_pcb);
593 	register struct mbuf *m;
594 	register struct spidp *si;
595 	struct ns_errp *ep;
596 	struct sockbuf *sb;
597 	int badseq, len;
598 	struct mbuf *firstbad, *m0;
599 
600 	if (cb) {
601 		/*
602 		 * The notification that we have sent
603 		 * too much is bad news -- we will
604 		 * have to go through queued up so far
605 		 * splitting ones which are too big and
606 		 * reassigning sequence numbers and checksums.
607 		 * we should then retransmit all packets from
608 		 * one above the offending packet to the last one
609 		 * we had sent (or our allocation)
610 		 * then the offending one so that the any queued
611 		 * data at our destination will be discarded.
612 		 */
613 		 ep = (struct ns_errp *)nsp->nsp_notify_param;
614 		 sb = &nsp->nsp_socket->so_snd;
615 		 cb->s_mtu = ep->ns_err_param;
616 		 badseq = SI(&ep->ns_err_idp)->si_seq;
617 		 for (m = sb->sb_mb; m; m = m->m_act) {
618 			si = mtod(m, struct spidp *);
619 			if (si->si_seq == badseq)
620 				break;
621 		 }
622 		 if (m == 0) return;
623 		 firstbad = m;
624 		 /*for (;;) {*/
625 			/* calculate length */
626 			for (m0 = m, len = 0; m ; m = m->m_next)
627 				len += m->m_len;
628 			if (len > cb->s_mtu) {
629 			}
630 		/* FINISH THIS
631 		} */
632 	}
633 }
634 #endif
635 
636 spp_output(cb, m0)
637 	register struct sppcb *cb;
638 	struct mbuf *m0;
639 {
640 	struct socket *so = cb->s_nspcb->nsp_socket;
641 	register struct mbuf *m;
642 	register struct spidp *si = (struct spidp *) 0;
643 	register struct sockbuf *sb = &so->so_snd;
644 	int len = 0, win, rcv_win;
645 	short span, off;
646 	u_short alo, oalo;
647 	int error = 0, idle, sendalot;
648 	u_short lookfor = 0;
649 	struct mbuf *mprev;
650 	extern int idpcksum;
651 
652 	if (m0) {
653 		int mtu = cb->s_mtu;
654 		int datalen;
655 		/*
656 		 * Make sure that packet isn't too big.
657 		 */
658 		for (m = m0; m ; m = m->m_next) {
659 			mprev = m;
660 			len += m->m_len;
661 		}
662 		datalen = (cb->s_flags & SF_HO) ?
663 				len - sizeof (struct sphdr) : len;
664 		if (datalen > mtu) {
665 			if (cb->s_flags & SF_PI) {
666 				m_freem(m0);
667 				return (EMSGSIZE);
668 			} else {
669 				int off = 0;
670 				int oldEM = cb->s_cc & SP_EM;
671 
672 				cb->s_cc &= ~SP_EM;
673 				while (len > mtu) {
674 					m = m_copy(m0, off, mtu);
675 					if (m == NULL) {
676 						error = ENOBUFS;
677 						goto bad_copy;
678 					}
679 					error = spp_output(cb, m);
680 					if (error) {
681 					bad_copy:
682 						cb->s_cc |= oldEM;
683 						m_freem(m0);
684 						return(error);
685 					}
686 					m_adj(m0, mtu);
687 					len -= mtu;
688 				}
689 				cb->s_cc |= oldEM;
690 			}
691 		}
692 		/*
693 		 * Force length even, by adding a "garbage byte" if
694 		 * necessary.
695 		 */
696 		if (len & 1) {
697 			m = mprev;
698 			if (m->m_len + m->m_off < MMAXOFF)
699 				m->m_len++;
700 			else {
701 				struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA);
702 
703 				if (m1 == 0) {
704 					m_freem(m0);
705 					return (ENOBUFS);
706 				}
707 				m1->m_len = 1;
708 				m1->m_off = MMAXOFF - 1;
709 				m->m_next = m1;
710 			}
711 		}
712 		m = m_get(M_DONTWAIT, MT_HEADER);
713 		if (m == 0) {
714 			m_freem(m0);
715 			return (ENOBUFS);
716 		}
717 		/*
718 		 * Fill in mbuf with extended SP header
719 		 * and addresses and length put into network format.
720 		 * Long align so prepended ip headers will work on Gould.
721 		 */
722 		m->m_off = MMAXOFF - sizeof (struct spidp) - 2;
723 		m->m_len = sizeof (struct spidp);
724 		m->m_next = m0;
725 		si = mtod(m, struct spidp *);
726 		si->si_i = *cb->s_idp;
727 		si->si_s = cb->s_shdr;
728 		if ((cb->s_flags & SF_PI) && (cb->s_flags & SF_HO)) {
729 			register struct sphdr *sh;
730 			if (m0->m_len < sizeof (*sh)) {
731 				if((m0 = m_pullup(m0, sizeof(*sh))) == NULL) {
732 					(void) m_free(m);
733 					m_freem(m0);
734 					return (EINVAL);
735 				}
736 				m->m_next = m0;
737 			}
738 			sh = mtod(m0, struct sphdr *);
739 			si->si_dt = sh->sp_dt;
740 			si->si_cc |= sh->sp_cc & SP_EM;
741 			m0->m_len -= sizeof (*sh);
742 			m0->m_off += sizeof (*sh);
743 			len -= sizeof (*sh);
744 		}
745 		len += sizeof(*si);
746 		if (cb->s_oobflags & SF_SOOB) {
747 			/*
748 			 * Per jqj@cornell:
749 			 * make sure OB packets convey exactly 1 byte.
750 			 * If the packet is 1 byte or larger, we
751 			 * have already guaranted there to be at least
752 			 * one garbage byte for the checksum, and
753 			 * extra bytes shouldn't hurt!
754 			 */
755 			if (len > sizeof(*si)) {
756 				si->si_cc |= SP_OB;
757 				len = (1 + sizeof(*si));
758 			}
759 		}
760 		si->si_len = htons((u_short)len);
761 		/*
762 		 * queue stuff up for output
763 		 */
764 		sbappendrecord(sb, m);
765 		cb->s_seq++;
766 	}
767 	idle = (cb->s_smax == (cb->s_rack - 1));
768 again:
769 	sendalot = 0;
770 	off = cb->s_snxt - cb->s_rack;
771 	win = MIN(cb->s_swnd, (cb->s_cwnd/CUNIT));
772 
773 	/*
774 	 * If in persist timeout with window of 0, send a probe.
775 	 * Otherwise, if window is small but nonzero
776 	 * and timer expired, send what we can and go into
777 	 * transmit state.
778 	 */
779 	if (cb->s_force == 1 + TCPT_PERSIST) {
780 		if (win != 0) {
781 			cb->s_timer[TCPT_PERSIST] = 0;
782 			cb->s_rxtshift = 0;
783 		}
784 	}
785 	span = cb->s_seq - cb->s_rack;
786 	len = MIN(span, win) - off;
787 
788 	if (len < 0) {
789 		/*
790 		 * Window shrank after we went into it.
791 		 * If window shrank to 0, cancel pending
792 		 * restransmission and pull s_snxt back
793 		 * to (closed) window.  We will enter persist
794 		 * state below.  If the widndow didn't close completely,
795 		 * just wait for an ACK.
796 		 */
797 		len = 0;
798 		if (win == 0) {
799 			cb->s_timer[TCPT_REXMT] = 0;
800 			cb->s_snxt = cb->s_rack;
801 		}
802 	}
803 	if (len > 1)
804 		sendalot = 1;
805 	rcv_win = sbspace(&so->so_rcv);
806 
807 	/*
808 	 * Send if we owe peer an ACK.
809 	 */
810 	if (cb->s_oobflags & SF_SOOB) {
811 		/*
812 		 * must transmit this out of band packet
813 		 */
814 		cb->s_oobflags &= ~ SF_SOOB;
815 		sendalot = 1;
816 		sppstat.spps_sndurg++;
817 		goto found;
818 	}
819 	if (cb->s_flags & SF_ACKNOW)
820 		goto send;
821 	if (cb->s_state < TCPS_ESTABLISHED)
822 		goto send;
823 	/*
824 	 * Silly window can't happen in spp.
825 	 * Code from tcp deleted.
826 	 */
827 	if (len)
828 		goto send;
829 	/*
830 	 * Compare available window to amount of window
831 	 * known to peer (as advertised window less
832 	 * next expected input.)  If the difference is at least two
833 	 * packets or at least 35% of the mximum possible window,
834 	 * then want to send a window update to peer.
835 	 */
836 	if (rcv_win > 0) {
837 		u_short delta =  1 + cb->s_alo - cb->s_ack;
838 		int adv = rcv_win - (delta * cb->s_mtu);
839 
840 		if ((so->so_rcv.sb_cc == 0 && adv >= (2 * cb->s_mtu)) ||
841 		    (100 * adv / so->so_rcv.sb_hiwat >= 35)) {
842 			sppstat.spps_sndwinup++;
843 			cb->s_flags |= SF_ACKNOW;
844 			goto send;
845 		}
846 
847 	}
848 	/*
849 	 * Many comments from tcp_output.c are appropriate here
850 	 * including . . .
851 	 * If send window is too small, there is data to transmit, and no
852 	 * retransmit or persist is pending, then go to persist state.
853 	 * If nothing happens soon, send when timer expires:
854 	 * if window is nonzero, transmit what we can,
855 	 * otherwise send a probe.
856 	 */
857 	if (so->so_snd.sb_cc && cb->s_timer[TCPT_REXMT] == 0 &&
858 		cb->s_timer[TCPT_PERSIST] == 0) {
859 			cb->s_rxtshift = 0;
860 			spp_setpersist(cb);
861 	}
862 	/*
863 	 * No reason to send a packet, just return.
864 	 */
865 	cb->s_outx = 1;
866 	return (0);
867 
868 send:
869 	/*
870 	 * Find requested packet.
871 	 */
872 	si = 0;
873 	if (len > 0) {
874 		cb->s_want = cb->s_snxt;
875 		for (m = sb->sb_mb; m; m = m->m_act) {
876 			si = mtod(m, struct spidp *);
877 			if (SSEQ_LEQ(cb->s_snxt, si->si_seq))
878 				break;
879 		}
880 	found:
881 		if (si) {
882 			if (si->si_seq == cb->s_snxt)
883 					cb->s_snxt++;
884 				else
885 					sppstat.spps_sndvoid++, si = 0;
886 		}
887 	}
888 	/*
889 	 * update window
890 	 */
891 	if (rcv_win < 0)
892 		rcv_win = 0;
893 	oalo = alo = cb->s_ack - 1 + (rcv_win / ((short)cb->s_mtu));
894 	if (SSEQ_LT(alo, cb->s_alo))
895 		alo = cb->s_alo;
896 
897 	if (si) {
898 		/*
899 		 * must make a copy of this packet for
900 		 * idp_output to monkey with
901 		 */
902 		m = m_copy(dtom(si), 0, (int)M_COPYALL);
903 		if (m == NULL) {
904 			return (ENOBUFS);
905 		}
906 		m0 = m;
907 		si = mtod(m, struct spidp *);
908 		if (SSEQ_LT(si->si_seq, cb->s_smax))
909 			sppstat.spps_sndrexmitpack++;
910 		else
911 			sppstat.spps_sndpack++;
912 	} else if (cb->s_force || cb->s_flags & SF_ACKNOW) {
913 		/*
914 		 * Must send an acknowledgement or a probe
915 		 */
916 		if (cb->s_force)
917 			sppstat.spps_sndprobe++;
918 		if (cb->s_flags & SF_ACKNOW)
919 			sppstat.spps_sndacks++;
920 		m = m_get(M_DONTWAIT, MT_HEADER);
921 		if (m == 0) {
922 			return (ENOBUFS);
923 		}
924 		/*
925 		 * Fill in mbuf with extended SP header
926 		 * and addresses and length put into network format.
927 		 * Allign beginning of packet to long to prepend
928 		 * ifp's on loopback, or NSIP encaspulation for fussy cpu's.
929 		 */
930 		m->m_off = MMAXOFF - sizeof (struct spidp) - 2;
931 		m->m_len = sizeof (*si);
932 		m->m_next = 0;
933 		si = mtod(m, struct spidp *);
934 		si->si_i = *cb->s_idp;
935 		si->si_s = cb->s_shdr;
936 		si->si_seq = cb->s_smax + 1;
937 		si->si_len = htons(sizeof (*si));
938 		si->si_cc |= SP_SP;
939 	} else {
940 		cb->s_outx = 3;
941 		if (so->so_options & SO_DEBUG || traceallspps)
942 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
943 		return (0);
944 	}
945 	/*
946 	 * Stuff checksum and output datagram.
947 	 */
948 	if ((si->si_cc & SP_SP) == 0) {
949 		if (cb->s_force != (1 + TCPT_PERSIST) ||
950 		    cb->s_timer[TCPT_PERSIST] == 0) {
951 			/*
952 			 * If this is a new packet and we are not currently
953 			 * timing anything, time this one.
954 			 */
955 			if (SSEQ_LT(cb->s_smax, si->si_seq)) {
956 				cb->s_smax = si->si_seq;
957 				if (cb->s_rtt == 0) {
958 					sppstat.spps_segstimed++;
959 					cb->s_rtseq = si->si_seq;
960 					cb->s_rtt = 1;
961 				}
962 			}
963 			/*
964 			 * Set rexmt timer if not currently set,
965 			 * Initial value for retransmit timer is smoothed
966 			 * round-trip time + 2 * round-trip time variance.
967 			 * Initialize shift counter which is used for backoff
968 			 * of retransmit time.
969 			 */
970 			if (cb->s_timer[TCPT_REXMT] == 0 &&
971 			    cb->s_snxt != cb->s_rack) {
972 				cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
973 				if (cb->s_timer[TCPT_PERSIST]) {
974 					cb->s_timer[TCPT_PERSIST] = 0;
975 					cb->s_rxtshift = 0;
976 				}
977 			}
978 		} else if (SSEQ_LT(cb->s_smax, si->si_seq)) {
979 			cb->s_smax = si->si_seq;
980 		}
981 	} else if (cb->s_state < TCPS_ESTABLISHED) {
982 		if (cb->s_rtt == 0)
983 			cb->s_rtt = 1; /* Time initial handshake */
984 		if (cb->s_timer[TCPT_REXMT] == 0)
985 			cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
986 	}
987 	{
988 		/*
989 		 * Do not request acks when we ack their data packets or
990 		 * when we do a gratuitous window update.
991 		 */
992 		if (((si->si_cc & SP_SP) == 0) || cb->s_force)
993 				si->si_cc |= SP_SA;
994 		si->si_seq = htons(si->si_seq);
995 		si->si_alo = htons(alo);
996 		si->si_ack = htons(cb->s_ack);
997 
998 		if (idpcksum) {
999 			si->si_sum = 0;
1000 			len = ntohs(si->si_len);
1001 			if (len & 1)
1002 				len++;
1003 			si->si_sum = ns_cksum(dtom(si), len);
1004 		} else
1005 			si->si_sum = 0xffff;
1006 
1007 		cb->s_outx = 4;
1008 		if (so->so_options & SO_DEBUG || traceallspps)
1009 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
1010 
1011 		if (so->so_options & SO_DONTROUTE)
1012 			error = ns_output(m, (struct route *)0, NS_ROUTETOIF);
1013 		else
1014 			error = ns_output(m, &cb->s_nspcb->nsp_route, 0);
1015 	}
1016 	if (error) {
1017 		return (error);
1018 	}
1019 	sppstat.spps_sndtotal++;
1020 	/*
1021 	 * Data sent (as far as we can tell).
1022 	 * If this advertises a larger window than any other segment,
1023 	 * then remember the size of the advertized window.
1024 	 * Any pending ACK has now been sent.
1025 	 */
1026 	cb->s_force = 0;
1027 	cb->s_flags &= ~(SF_ACKNOW|SF_DELACK);
1028 	if (SSEQ_GT(alo, cb->s_alo))
1029 		cb->s_alo = alo;
1030 	if (sendalot)
1031 		goto again;
1032 	cb->s_outx = 5;
1033 	return (0);
1034 }
1035 
1036 int spp_do_persist_panics = 0;
1037 
1038 spp_setpersist(cb)
1039 	register struct sppcb *cb;
1040 {
1041 	register t = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1042 	extern int spp_backoff[];
1043 
1044 	if (cb->s_timer[TCPT_REXMT] && spp_do_persist_panics)
1045 		panic("spp_output REXMT");
1046 	/*
1047 	 * Start/restart persistance timer.
1048 	 */
1049 	TCPT_RANGESET(cb->s_timer[TCPT_PERSIST],
1050 	    t*spp_backoff[cb->s_rxtshift],
1051 	    TCPTV_PERSMIN, TCPTV_PERSMAX);
1052 	if (cb->s_rxtshift < TCP_MAXRXTSHIFT)
1053 		cb->s_rxtshift++;
1054 }
1055 /*ARGSUSED*/
1056 spp_ctloutput(req, so, level, name, value)
1057 	int req;
1058 	struct socket *so;
1059 	int name;
1060 	struct mbuf **value;
1061 {
1062 	register struct mbuf *m;
1063 	struct nspcb *nsp = sotonspcb(so);
1064 	register struct sppcb *cb;
1065 	int mask, error = 0;
1066 
1067 	if (level != NSPROTO_SPP) {
1068 		/* This will have to be changed when we do more general
1069 		   stacking of protocols */
1070 		return (idp_ctloutput(req, so, level, name, value));
1071 	}
1072 	if (nsp == NULL) {
1073 		error = EINVAL;
1074 		goto release;
1075 	} else
1076 		cb = nstosppcb(nsp);
1077 
1078 	switch (req) {
1079 
1080 	case PRCO_GETOPT:
1081 		if (value == NULL)
1082 			return (EINVAL);
1083 		m = m_get(M_DONTWAIT, MT_DATA);
1084 		if (m == NULL)
1085 			return (ENOBUFS);
1086 		switch (name) {
1087 
1088 		case SO_HEADERS_ON_INPUT:
1089 			mask = SF_HI;
1090 			goto get_flags;
1091 
1092 		case SO_HEADERS_ON_OUTPUT:
1093 			mask = SF_HO;
1094 		get_flags:
1095 			m->m_len = sizeof(short);
1096 			m->m_off = MMAXOFF - sizeof(short);
1097 			*mtod(m, short *) = cb->s_flags & mask;
1098 			break;
1099 
1100 		case SO_MTU:
1101 			m->m_len = sizeof(u_short);
1102 			m->m_off = MMAXOFF - sizeof(short);
1103 			*mtod(m, short *) = cb->s_mtu;
1104 			break;
1105 
1106 		case SO_LAST_HEADER:
1107 			m->m_len = sizeof(struct sphdr);
1108 			m->m_off = MMAXOFF - sizeof(struct sphdr);
1109 			*mtod(m, struct sphdr *) = cb->s_rhdr;
1110 			break;
1111 
1112 		case SO_DEFAULT_HEADERS:
1113 			m->m_len = sizeof(struct spidp);
1114 			m->m_off = MMAXOFF - sizeof(struct sphdr);
1115 			*mtod(m, struct sphdr *) = cb->s_shdr;
1116 			break;
1117 
1118 		default:
1119 			error = EINVAL;
1120 		}
1121 		*value = m;
1122 		break;
1123 
1124 	case PRCO_SETOPT:
1125 		if (value == 0 || *value == 0) {
1126 			error = EINVAL;
1127 			break;
1128 		}
1129 		switch (name) {
1130 			int *ok;
1131 
1132 		case SO_HEADERS_ON_INPUT:
1133 			mask = SF_HI;
1134 			goto set_head;
1135 
1136 		case SO_HEADERS_ON_OUTPUT:
1137 			mask = SF_HO;
1138 		set_head:
1139 			if (cb->s_flags & SF_PI) {
1140 				ok = mtod(*value, int *);
1141 				if (*ok)
1142 					cb->s_flags |= mask;
1143 				else
1144 					cb->s_flags &= ~mask;
1145 			} else error = EINVAL;
1146 			break;
1147 
1148 		case SO_MTU:
1149 			cb->s_mtu = *(mtod(*value, u_short *));
1150 			break;
1151 
1152 		case SO_DEFAULT_HEADERS:
1153 			{
1154 				register struct sphdr *sp
1155 						= mtod(*value, struct sphdr *);
1156 				cb->s_dt = sp->sp_dt;
1157 				cb->s_cc = sp->sp_cc & SP_EM;
1158 			}
1159 			break;
1160 
1161 		default:
1162 			error = EINVAL;
1163 		}
1164 		m_freem(*value);
1165 		break;
1166 	}
1167 	release:
1168 		return (error);
1169 }
1170 
1171 /*ARGSUSED*/
1172 spp_usrreq(so, req, m, nam, rights)
1173 	struct socket *so;
1174 	int req;
1175 	struct mbuf *m, *nam, *rights;
1176 {
1177 	struct nspcb *nsp = sotonspcb(so);
1178 	register struct sppcb *cb;
1179 	int s = splnet();
1180 	int error = 0, ostate;
1181 	struct mbuf *mm;
1182 	register struct sockbuf *sb;
1183 
1184 	if (req == PRU_CONTROL)
1185                 return (ns_control(so, (int)m, (caddr_t)nam,
1186 			(struct ifnet *)rights));
1187 	if (rights && rights->m_len) {
1188 		error = EINVAL;
1189 		goto release;
1190 	}
1191 	if (nsp == NULL) {
1192 		if (req != PRU_ATTACH) {
1193 			error = EINVAL;
1194 			goto release;
1195 		}
1196 	} else
1197 		cb = nstosppcb(nsp);
1198 
1199 	ostate = cb ? cb->s_state : 0;
1200 
1201 	switch (req) {
1202 
1203 	case PRU_ATTACH:
1204 		if (nsp != NULL) {
1205 			error = EISCONN;
1206 			break;
1207 		}
1208 		error = ns_pcballoc(so, &nspcb);
1209 		if (error)
1210 			break;
1211 		error = soreserve(so, 3072, 3072);
1212 		if (error)
1213 			break;
1214 		nsp = sotonspcb(so);
1215 
1216 		mm = m_getclr(M_DONTWAIT, MT_PCB);
1217 		sb = &so->so_snd;
1218 
1219 		if (mm == NULL) {
1220 			error = ENOBUFS;
1221 			break;
1222 		}
1223 		cb = mtod(mm, struct sppcb *);
1224 		mm = m_getclr(M_DONTWAIT, MT_HEADER);
1225 		if (mm == NULL) {
1226 			m_free(dtom(m));
1227 			error = ENOBUFS;
1228 			break;
1229 		}
1230 		cb->s_idp = mtod(mm, struct idp *);
1231 		cb->s_state = TCPS_LISTEN;
1232 		cb->s_smax = -1;
1233 		cb->s_swl1 = -1;
1234 		cb->s_q.si_next = cb->s_q.si_prev = &cb->s_q;
1235 		cb->s_nspcb = nsp;
1236 		cb->s_mtu = 576 - sizeof (struct spidp);
1237 		cb->s_cwnd = sbspace(sb) * CUNIT / cb->s_mtu;
1238 		cb->s_ssthresh = cb->s_cwnd;
1239 		cb->s_cwmx = sb->sb_mbmax * CUNIT /
1240 				(2 * sizeof (struct spidp));
1241 		/* Above is recomputed when connecting to account
1242 		   for changed buffering or mtu's */
1243 		cb->s_rtt = TCPTV_SRTTBASE;
1244 		cb->s_rttvar = TCPTV_SRTTDFLT << 2;
1245 		TCPT_RANGESET(cb->s_rxtcur,
1246 		    ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
1247 		    TCPTV_MIN, TCPTV_REXMTMAX);
1248 		nsp->nsp_pcb = (caddr_t) cb;
1249 		break;
1250 
1251 	case PRU_DETACH:
1252 		if (nsp == NULL) {
1253 			error = ENOTCONN;
1254 			break;
1255 		}
1256 		if (cb->s_state > TCPS_LISTEN)
1257 			cb = spp_disconnect(cb);
1258 		else
1259 			cb = spp_close(cb);
1260 		break;
1261 
1262 	case PRU_BIND:
1263 		error = ns_pcbbind(nsp, nam);
1264 		break;
1265 
1266 	case PRU_LISTEN:
1267 		if (nsp->nsp_lport == 0)
1268 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1269 		if (error == 0)
1270 			cb->s_state = TCPS_LISTEN;
1271 		break;
1272 
1273 	/*
1274 	 * Initiate connection to peer.
1275 	 * Enter SYN_SENT state, and mark socket as connecting.
1276 	 * Start keep-alive timer, setup prototype header,
1277 	 * Send initial system packet requesting connection.
1278 	 */
1279 	case PRU_CONNECT:
1280 		if (nsp->nsp_lport == 0) {
1281 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1282 			if (error)
1283 				break;
1284 		}
1285 		error = ns_pcbconnect(nsp, nam);
1286 		if (error)
1287 			break;
1288 		soisconnecting(so);
1289 		sppstat.spps_connattempt++;
1290 		cb->s_state = TCPS_SYN_SENT;
1291 		cb->s_did = 0;
1292 		spp_template(cb);
1293 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
1294 		cb->s_force = 1 + TCPTV_KEEP;
1295 		/*
1296 		 * Other party is required to respond to
1297 		 * the port I send from, but he is not
1298 		 * required to answer from where I am sending to,
1299 		 * so allow wildcarding.
1300 		 * original port I am sending to is still saved in
1301 		 * cb->s_dport.
1302 		 */
1303 		nsp->nsp_fport = 0;
1304 		error = spp_output(cb, (struct mbuf *) 0);
1305 		break;
1306 
1307 	case PRU_CONNECT2:
1308 		error = EOPNOTSUPP;
1309 		break;
1310 
1311 	/*
1312 	 * We may decide later to implement connection closing
1313 	 * handshaking at the spp level optionally.
1314 	 * here is the hook to do it:
1315 	 */
1316 	case PRU_DISCONNECT:
1317 		cb = spp_disconnect(cb);
1318 		break;
1319 
1320 	/*
1321 	 * Accept a connection.  Essentially all the work is
1322 	 * done at higher levels; just return the address
1323 	 * of the peer, storing through addr.
1324 	 */
1325 	case PRU_ACCEPT: {
1326 		struct sockaddr_ns *sns = mtod(nam, struct sockaddr_ns *);
1327 
1328 		nam->m_len = sizeof (struct sockaddr_ns);
1329 		sns->sns_family = AF_NS;
1330 		sns->sns_addr = nsp->nsp_faddr;
1331 		break;
1332 		}
1333 
1334 	case PRU_SHUTDOWN:
1335 		socantsendmore(so);
1336 		cb = spp_usrclosed(cb);
1337 		if (cb)
1338 			error = spp_output(cb, (struct mbuf *) 0);
1339 		break;
1340 
1341 	/*
1342 	 * After a receive, possibly send acknowledgment
1343 	 * updating allocation.
1344 	 */
1345 	case PRU_RCVD:
1346 		cb->s_flags |= SF_RVD;
1347 		(void) spp_output(cb, (struct mbuf *) 0);
1348 		cb->s_flags &= ~SF_RVD;
1349 		break;
1350 
1351 	case PRU_ABORT:
1352 		(void) spp_drop(cb, ECONNABORTED);
1353 		break;
1354 
1355 	case PRU_SENSE:
1356 	case PRU_CONTROL:
1357 		m = NULL;
1358 		error = EOPNOTSUPP;
1359 		break;
1360 
1361 	case PRU_RCVOOB:
1362 		if ((cb->s_oobflags & SF_IOOB) || so->so_oobmark ||
1363 		    (so->so_state & SS_RCVATMARK)) {
1364 			m->m_len = 1;
1365 			*mtod(m, caddr_t) = cb->s_iobc;
1366 			break;
1367 		}
1368 		error = EINVAL;
1369 		break;
1370 
1371 	case PRU_SENDOOB:
1372 		if (sbspace(&so->so_snd) < -512) {
1373 			error = ENOBUFS;
1374 			break;
1375 		}
1376 		cb->s_oobflags |= SF_SOOB;
1377 		/* fall into */
1378 	case PRU_SEND:
1379 		error = spp_output(cb, m);
1380 		m = NULL;
1381 		break;
1382 
1383 	case PRU_SOCKADDR:
1384 		ns_setsockaddr(nsp, nam);
1385 		break;
1386 
1387 	case PRU_PEERADDR:
1388 		ns_setpeeraddr(nsp, nam);
1389 		break;
1390 
1391 	case PRU_SLOWTIMO:
1392 		cb = spp_timers(cb, (int)nam);
1393 		req |= ((int)nam) << 8;
1394 		break;
1395 
1396 	case PRU_FASTTIMO:
1397 	case PRU_PROTORCV:
1398 	case PRU_PROTOSEND:
1399 		error =  EOPNOTSUPP;
1400 		break;
1401 
1402 	default:
1403 		panic("sp_usrreq");
1404 	}
1405 	if (cb && (so->so_options & SO_DEBUG || traceallspps))
1406 		spp_trace(SA_USER, (u_char)ostate, cb, (struct spidp *)0, req);
1407 release:
1408 	if (m != NULL)
1409 		m_freem(m);
1410 	splx(s);
1411 	return (error);
1412 }
1413 
1414 spp_usrreq_sp(so, req, m, nam, rights)
1415 	struct socket *so;
1416 	int req;
1417 	struct mbuf *m, *nam, *rights;
1418 {
1419 	int error = spp_usrreq(so, req, m, nam, rights);
1420 
1421 	if (req == PRU_ATTACH && error == 0) {
1422 		struct nspcb *nsp = sotonspcb(so);
1423 		((struct sppcb *)nsp->nsp_pcb)->s_flags |=
1424 					(SF_HI | SF_HO | SF_PI);
1425 	}
1426 	return (error);
1427 }
1428 
1429 /*
1430  * Create template to be used to send spp packets on a connection.
1431  * Called after host entry created, fills
1432  * in a skeletal spp header (choosing connection id),
1433  * minimizing the amount of work necessary when the connection is used.
1434  */
1435 spp_template(cb)
1436 	register struct sppcb *cb;
1437 {
1438 	register struct nspcb *nsp = cb->s_nspcb;
1439 	register struct idp *idp = cb->s_idp;
1440 	register struct sockbuf *sb = &(nsp->nsp_socket->so_snd);
1441 
1442 	idp->idp_pt = NSPROTO_SPP;
1443 	idp->idp_sna = nsp->nsp_laddr;
1444 	idp->idp_dna = nsp->nsp_faddr;
1445 	cb->s_sid = htons(spp_iss);
1446 	spp_iss += SPP_ISSINCR/2;
1447 	cb->s_alo = 1;
1448 	cb->s_cwnd = (sbspace(sb) * CUNIT) / cb->s_mtu;
1449 	cb->s_ssthresh = cb->s_cwnd; /* Try to expand fast to full complement
1450 					of large packets */
1451 	cb->s_cwmx = (sb->sb_mbmax * CUNIT) / (2 * sizeof(struct spidp));
1452 	cb->s_cwmx = MAX(cb->s_cwmx, cb->s_cwnd);
1453 		/* But allow for lots of little packets as well */
1454 }
1455 
1456 /*
1457  * Close a SPIP control block:
1458  *	discard spp control block itself
1459  *	discard ns protocol control block
1460  *	wake up any sleepers
1461  */
1462 struct sppcb *
1463 spp_close(cb)
1464 	register struct sppcb *cb;
1465 {
1466 	register struct spidp_q *s;
1467 	struct nspcb *nsp = cb->s_nspcb;
1468 	struct socket *so = nsp->nsp_socket;
1469 	register struct mbuf *m;
1470 
1471 	s = cb->s_q.si_next;
1472 	while (s != &(cb->s_q)) {
1473 		s = s->si_next;
1474 		m = dtom(s->si_prev);
1475 		remque(s->si_prev);
1476 		m_freem(m);
1477 	}
1478 	(void) m_free(dtom(cb->s_idp));
1479 	(void) m_free(dtom(cb));
1480 	nsp->nsp_pcb = 0;
1481 	soisdisconnected(so);
1482 	ns_pcbdetach(nsp);
1483 	sppstat.spps_closed++;
1484 	return ((struct sppcb *)0);
1485 }
1486 /*
1487  *	Someday we may do level 3 handshaking
1488  *	to close a connection or send a xerox style error.
1489  *	For now, just close.
1490  */
1491 struct sppcb *
1492 spp_usrclosed(cb)
1493 	register struct sppcb *cb;
1494 {
1495 	return (spp_close(cb));
1496 }
1497 struct sppcb *
1498 spp_disconnect(cb)
1499 	register struct sppcb *cb;
1500 {
1501 	return (spp_close(cb));
1502 }
1503 /*
1504  * Drop connection, reporting
1505  * the specified error.
1506  */
1507 struct sppcb *
1508 spp_drop(cb, errno)
1509 	register struct sppcb *cb;
1510 	int errno;
1511 {
1512 	struct socket *so = cb->s_nspcb->nsp_socket;
1513 
1514 	/*
1515 	 * someday, in the xerox world
1516 	 * we will generate error protocol packets
1517 	 * announcing that the socket has gone away.
1518 	 */
1519 	if (TCPS_HAVERCVDSYN(cb->s_state)) {
1520 		sppstat.spps_drops++;
1521 		cb->s_state = TCPS_CLOSED;
1522 		/*(void) tcp_output(cb);*/
1523 	} else
1524 		sppstat.spps_conndrops++;
1525 	so->so_error = errno;
1526 	return (spp_close(cb));
1527 }
1528 
1529 spp_abort(nsp)
1530 	struct nspcb *nsp;
1531 {
1532 
1533 	(void) spp_close((struct sppcb *)nsp->nsp_pcb);
1534 }
1535 
1536 long	spp_backoff[TCP_MAXRXTSHIFT+1] =
1537     { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
1538 /*
1539  * Fast timeout routine for processing delayed acks
1540  */
1541 spp_fasttimo()
1542 {
1543 	register struct nspcb *nsp;
1544 	register struct sppcb *cb;
1545 	int s = splnet();
1546 
1547 	nsp = nspcb.nsp_next;
1548 	if (nsp)
1549 	for (; nsp != &nspcb; nsp = nsp->nsp_next)
1550 		if ((cb = (struct sppcb *)nsp->nsp_pcb) &&
1551 		    (cb->s_flags & SF_DELACK)) {
1552 			cb->s_flags &= ~SF_DELACK;
1553 			cb->s_flags |= SF_ACKNOW;
1554 			sppstat.spps_delack++;
1555 			(void) spp_output(cb, (struct mbuf *) 0);
1556 		}
1557 	splx(s);
1558 }
1559 
1560 /*
1561  * spp protocol timeout routine called every 500 ms.
1562  * Updates the timers in all active pcb's and
1563  * causes finite state machine actions if timers expire.
1564  */
1565 spp_slowtimo()
1566 {
1567 	register struct nspcb *ip, *ipnxt;
1568 	register struct sppcb *cb;
1569 	int s = splnet();
1570 	register int i;
1571 
1572 	/*
1573 	 * Search through tcb's and update active timers.
1574 	 */
1575 	ip = nspcb.nsp_next;
1576 	if (ip == 0) {
1577 		splx(s);
1578 		return;
1579 	}
1580 	while (ip != &nspcb) {
1581 		cb = nstosppcb(ip);
1582 		ipnxt = ip->nsp_next;
1583 		if (cb == 0)
1584 			goto tpgone;
1585 		for (i = 0; i < TCPT_NTIMERS; i++) {
1586 			if (cb->s_timer[i] && --cb->s_timer[i] == 0) {
1587 				(void) spp_usrreq(cb->s_nspcb->nsp_socket,
1588 				    PRU_SLOWTIMO, (struct mbuf *)0,
1589 				    (struct mbuf *)i, (struct mbuf *)0);
1590 				if (ipnxt->nsp_prev != ip)
1591 					goto tpgone;
1592 			}
1593 		}
1594 		cb->s_idle++;
1595 		if (cb->s_rtt)
1596 			cb->s_rtt++;
1597 tpgone:
1598 		ip = ipnxt;
1599 	}
1600 	spp_iss += SPP_ISSINCR/PR_SLOWHZ;		/* increment iss */
1601 	splx(s);
1602 }
1603 /*
1604  * SPP timer processing.
1605  */
1606 struct sppcb *
1607 spp_timers(cb, timer)
1608 	register struct sppcb *cb;
1609 	int timer;
1610 {
1611 	long rexmt;
1612 	int win;
1613 
1614 	cb->s_force = 1 + timer;
1615 	switch (timer) {
1616 
1617 	/*
1618 	 * 2 MSL timeout in shutdown went off.  TCP deletes connection
1619 	 * control block.
1620 	 */
1621 	case TCPT_2MSL:
1622 		printf("spp: TCPT_2MSL went off for no reason\n");
1623 		cb->s_timer[timer] = 0;
1624 		break;
1625 
1626 	/*
1627 	 * Retransmission timer went off.  Message has not
1628 	 * been acked within retransmit interval.  Back off
1629 	 * to a longer retransmit interval and retransmit one packet.
1630 	 */
1631 	case TCPT_REXMT:
1632 		if (++cb->s_rxtshift > TCP_MAXRXTSHIFT) {
1633 			cb->s_rxtshift = TCP_MAXRXTSHIFT;
1634 			sppstat.spps_timeoutdrop++;
1635 			cb = spp_drop(cb, ETIMEDOUT);
1636 			break;
1637 		}
1638 		sppstat.spps_rexmttimeo++;
1639 		rexmt = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1640 		rexmt *= spp_backoff[cb->s_rxtshift];
1641 		TCPT_RANGESET(cb->s_rxtcur, rexmt, TCPTV_MIN, TCPTV_REXMTMAX);
1642 		cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
1643 		/*
1644 		 * If we have backed off fairly far, our srtt
1645 		 * estimate is probably bogus.  Clobber it
1646 		 * so we'll take the next rtt measurement as our srtt;
1647 		 * move the current srtt into rttvar to keep the current
1648 		 * retransmit times until then.
1649 		 */
1650 		if (cb->s_rxtshift > TCP_MAXRXTSHIFT / 4 ) {
1651 			cb->s_rttvar += (cb->s_srtt >> 2);
1652 			cb->s_srtt = 0;
1653 		}
1654 		cb->s_snxt = cb->s_rack;
1655 		/*
1656 		 * If timing a packet, stop the timer.
1657 		 */
1658 		cb->s_rtt = 0;
1659 		/*
1660 		 * See very long discussion in tcp_timer.c about congestion
1661 		 * window and sstrhesh
1662 		 */
1663 		win = MIN(cb->s_swnd, (cb->s_cwnd/CUNIT)) / 2;
1664 		if (win < 2)
1665 			win = 2;
1666 		cb->s_cwnd = CUNIT;
1667 		cb->s_ssthresh = win;
1668 		(void) spp_output(cb, (struct mbuf *) 0);
1669 		break;
1670 
1671 	/*
1672 	 * Persistance timer into zero window.
1673 	 * Force a probe to be sent.
1674 	 */
1675 	case TCPT_PERSIST:
1676 		sppstat.spps_persisttimeo++;
1677 		spp_setpersist(cb);
1678 		(void) spp_output(cb, (struct mbuf *) 0);
1679 		break;
1680 
1681 	/*
1682 	 * Keep-alive timer went off; send something
1683 	 * or drop connection if idle for too long.
1684 	 */
1685 	case TCPT_KEEP:
1686 		sppstat.spps_keeptimeo++;
1687 		if (cb->s_state < TCPS_ESTABLISHED)
1688 			goto dropit;
1689 		if (cb->s_nspcb->nsp_socket->so_options & SO_KEEPALIVE) {
1690 		    	if (cb->s_idle >= TCPTV_MAXIDLE)
1691 				goto dropit;
1692 			sppstat.spps_keepprobe++;
1693 			(void) spp_output(cb, (struct mbuf *) 0);
1694 		} else
1695 			cb->s_idle = 0;
1696 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
1697 		break;
1698 	dropit:
1699 		sppstat.spps_keepdrops++;
1700 		cb = spp_drop(cb, ETIMEDOUT);
1701 		break;
1702 	}
1703 	return (cb);
1704 }
1705 int SppcbSize = sizeof (struct sppcb);
1706 int NspcbSize = sizeof (struct nspcb);
1707