xref: /csrg-svn/sys/netns/spp_usrreq.c (revision 44507)
1 /*
2  * Copyright (c) 1984, 1985, 1986, 1987 Regents of the University of California.
3  * All rights reserved.
4  *
5  * %sccs.include.redist.c%
6  *
7  *	@(#)spp_usrreq.c	7.14 (Berkeley) 06/28/90
8  */
9 
10 #include "param.h"
11 #include "systm.h"
12 #include "user.h"
13 #include "malloc.h"
14 #include "mbuf.h"
15 #include "protosw.h"
16 #include "socket.h"
17 #include "socketvar.h"
18 #include "errno.h"
19 
20 #include "../net/if.h"
21 #include "../net/route.h"
22 #include "../netinet/tcp_fsm.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_timer.h"
32 #include "spp_var.h"
33 #include "spp_debug.h"
34 
35 /*
36  * SP protocol implementation.
37  */
38 spp_init()
39 {
40 
41 	spp_iss = 1; /* WRONG !! should fish it out of TODR */
42 }
43 struct spidp spp_savesi;
44 int traceallspps = 0;
45 extern int sppconsdebug;
46 int spp_hardnosed;
47 int spp_use_delack = 0;
48 u_short spp_newchecks[50];
49 
50 /*ARGSUSED*/
51 spp_input(m, nsp)
52 	register struct mbuf *m;
53 	register struct nspcb *nsp;
54 {
55 	register struct sppcb *cb;
56 	register struct spidp *si = mtod(m, struct spidp *);
57 	register struct socket *so;
58 	short ostate;
59 	int dropsocket = 0;
60 
61 
62 	sppstat.spps_rcvtotal++;
63 	if (nsp == 0) {
64 		panic("No nspcb in spp_input\n");
65 		return;
66 	}
67 
68 	cb = nstosppcb(nsp);
69 	if (cb == 0) goto bad;
70 
71 	if (m->m_len < sizeof(*si)) {
72 		if ((m = m_pullup(m, sizeof(*si))) == 0) {
73 			sppstat.spps_rcvshort++;
74 			return;
75 		}
76 		si = mtod(m, struct spidp *);
77 	}
78 	si->si_seq = ntohs(si->si_seq);
79 	si->si_ack = ntohs(si->si_ack);
80 	si->si_alo = ntohs(si->si_alo);
81 
82 	so = nsp->nsp_socket;
83 	if (so->so_options & SO_DEBUG || traceallspps) {
84 		ostate = cb->s_state;
85 		spp_savesi = *si;
86 	}
87 	if (so->so_options & SO_ACCEPTCONN) {
88 		struct sppcb *ocb = cb;
89 
90 		so = sonewconn(so, 0);
91 		if (so == 0) {
92 			goto drop;
93 		}
94 		/*
95 		 * This is ugly, but ....
96 		 *
97 		 * Mark socket as temporary until we're
98 		 * committed to keeping it.  The code at
99 		 * ``drop'' and ``dropwithreset'' check the
100 		 * flag dropsocket to see if the temporary
101 		 * socket created here should be discarded.
102 		 * We mark the socket as discardable until
103 		 * we're committed to it below in TCPS_LISTEN.
104 		 */
105 		dropsocket++;
106 		nsp = (struct nspcb *)so->so_pcb;
107 		nsp->nsp_laddr = si->si_dna;
108 		cb = nstosppcb(nsp);
109 		cb->s_mtu = ocb->s_mtu;		/* preserve sockopts */
110 		cb->s_flags = ocb->s_flags;	/* preserve sockopts */
111 		cb->s_flags2 = ocb->s_flags2;	/* preserve sockopts */
112 		cb->s_state = TCPS_LISTEN;
113 	}
114 
115 	/*
116 	 * Packet received on connection.
117 	 * reset idle time and keep-alive timer;
118 	 */
119 	cb->s_idle = 0;
120 	cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
121 
122 	switch (cb->s_state) {
123 
124 	case TCPS_LISTEN:{
125 		struct mbuf *am;
126 		register struct sockaddr_ns *sns;
127 		struct ns_addr laddr;
128 
129 		/*
130 		 * If somebody here was carying on a conversation
131 		 * and went away, and his pen pal thinks he can
132 		 * still talk, we get the misdirected packet.
133 		 */
134 		if (spp_hardnosed && (si->si_did != 0 || si->si_seq != 0)) {
135 			spp_istat.gonawy++;
136 			goto dropwithreset;
137 		}
138 		am = m_get(M_DONTWAIT, MT_SONAME);
139 		if (am == NULL)
140 			goto drop;
141 		am->m_len = sizeof (struct sockaddr_ns);
142 		sns = mtod(am, struct sockaddr_ns *);
143 		sns->sns_len = sizeof(*sns);
144 		sns->sns_family = AF_NS;
145 		sns->sns_addr = si->si_sna;
146 		laddr = nsp->nsp_laddr;
147 		if (ns_nullhost(laddr))
148 			nsp->nsp_laddr = si->si_dna;
149 		if (ns_pcbconnect(nsp, am)) {
150 			nsp->nsp_laddr = laddr;
151 			(void) m_free(am);
152 			spp_istat.noconn++;
153 			goto drop;
154 		}
155 		(void) m_free(am);
156 		spp_template(cb);
157 		dropsocket = 0;		/* committed to socket */
158 		cb->s_did = si->si_sid;
159 		cb->s_rack = si->si_ack;
160 		cb->s_ralo = si->si_alo;
161 #define THREEWAYSHAKE
162 #ifdef THREEWAYSHAKE
163 		cb->s_state = TCPS_SYN_RECEIVED;
164 		cb->s_force = 1 + SPPT_KEEP;
165 		sppstat.spps_accepts++;
166 		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
167 		}
168 		break;
169 	/*
170 	 * This state means that we have heard a response
171 	 * to our acceptance of their connection
172 	 * It is probably logically unnecessary in this
173 	 * implementation.
174 	 */
175 	 case TCPS_SYN_RECEIVED: {
176 		if (si->si_did!=cb->s_sid) {
177 			spp_istat.wrncon++;
178 			goto drop;
179 		}
180 #endif
181 		nsp->nsp_fport =  si->si_sport;
182 		cb->s_timer[SPPT_REXMT] = 0;
183 		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
184 		soisconnected(so);
185 		cb->s_state = TCPS_ESTABLISHED;
186 		sppstat.spps_accepts++;
187 		}
188 		break;
189 
190 	/*
191 	 * This state means that we have gotten a response
192 	 * to our attempt to establish a connection.
193 	 * We fill in the data from the other side,
194 	 * telling us which port to respond to, instead of the well-
195 	 * known one we might have sent to in the first place.
196 	 * We also require that this is a response to our
197 	 * connection id.
198 	 */
199 	case TCPS_SYN_SENT:
200 		if (si->si_did!=cb->s_sid) {
201 			spp_istat.notme++;
202 			goto drop;
203 		}
204 		sppstat.spps_connects++;
205 		cb->s_did = si->si_sid;
206 		cb->s_rack = si->si_ack;
207 		cb->s_ralo = si->si_alo;
208 		cb->s_dport = nsp->nsp_fport =  si->si_sport;
209 		cb->s_timer[SPPT_REXMT] = 0;
210 		cb->s_flags |= SF_ACKNOW;
211 		soisconnected(so);
212 		cb->s_state = TCPS_ESTABLISHED;
213 		/* Use roundtrip time of connection request for initial rtt */
214 		if (cb->s_rtt) {
215 			cb->s_srtt = cb->s_rtt << 3;
216 			cb->s_rttvar = cb->s_rtt << 1;
217 			SPPT_RANGESET(cb->s_rxtcur,
218 			    ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1,
219 			    SPPTV_MIN, SPPTV_REXMTMAX);
220 			    cb->s_rtt = 0;
221 		}
222 	}
223 	if (so->so_options & SO_DEBUG || traceallspps)
224 		spp_trace(SA_INPUT, (u_char)ostate, cb, &spp_savesi, 0);
225 
226 	m->m_len -= sizeof (struct idp);
227 	m->m_pkthdr.len -= sizeof (struct idp);
228 	m->m_data += sizeof (struct idp);
229 
230 	if (spp_reass(cb, si)) {
231 		(void) 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 + 1)) {
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 + SPPT_REXMT;
303 				(void) spp_output(cb, (struct mbuf *)0);
304 				cb->s_timer[SPPT_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 		SPPT_RANGESET(cb->s_rxtcur,
354 			((cb->s_srtt >> 2) + cb->s_rttvar) >> 1,
355 			SPPTV_MIN, SPPTV_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[SPPT_REXMT] = 0;
365 		cb->s_flags |= SF_RXT;
366 	} else if (cb->s_timer[SPPT_PERSIST] == 0)
367 		cb->s_timer[SPPT_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 	while ((m = so->so_snd.sb_mb) != NULL) {
382 		if (SSEQ_LT((mtod(m, struct spidp *))->si_seq, si->si_ack))
383 			sbdroprecord(&so->so_snd);
384 		else
385 			break;
386 	}
387 	sowwakeup(so);
388 	cb->s_rack = si->si_ack;
389 update_window:
390 	if (SSEQ_LT(cb->s_snxt, cb->s_rack))
391 		cb->s_snxt = cb->s_rack;
392 	if (SSEQ_LT(cb->s_swl1, si->si_seq) || cb->s_swl1 == si->si_seq &&
393 	    (SSEQ_LT(cb->s_swl2, si->si_ack) ||
394 	     cb->s_swl2 == si->si_ack && SSEQ_LT(cb->s_ralo, si->si_alo))) {
395 		/* keep track of pure window updates */
396 		if ((si->si_cc & SP_SP) && cb->s_swl2 == si->si_ack
397 		    && SSEQ_LT(cb->s_ralo, si->si_alo)) {
398 			sppstat.spps_rcvwinupd++;
399 			sppstat.spps_rcvdupack--;
400 		}
401 		cb->s_ralo = si->si_alo;
402 		cb->s_swl1 = si->si_seq;
403 		cb->s_swl2 = si->si_ack;
404 		cb->s_swnd = (1 + si->si_alo - si->si_ack);
405 		if (cb->s_swnd > cb->s_smxw)
406 			cb->s_smxw = cb->s_swnd;
407 		cb->s_flags |= SF_WIN;
408 	}
409 	/*
410 	 * If this packet number is higher than that which
411 	 * we have allocated refuse it, unless urgent
412 	 */
413 	if (SSEQ_GT(si->si_seq, cb->s_alo)) {
414 		if (si->si_cc & SP_SP) {
415 			sppstat.spps_rcvwinprobe++;
416 			return (1);
417 		} else
418 			sppstat.spps_rcvpackafterwin++;
419 		if (si->si_cc & SP_OB) {
420 			if (SSEQ_GT(si->si_seq, cb->s_alo + 60)) {
421 				ns_error(dtom(si), NS_ERR_FULLUP, 0);
422 				return (0);
423 			} /* else queue this packet; */
424 		} else {
425 			/*register struct socket *so = cb->s_nspcb->nsp_socket;
426 			if (so->so_state && SS_NOFDREF) {
427 				ns_error(dtom(si), NS_ERR_NOSOCK, 0);
428 				(void)spp_close(cb);
429 			} else
430 				       would crash system*/
431 			spp_istat.notyet++;
432 			ns_error(dtom(si), NS_ERR_FULLUP, 0);
433 			return (0);
434 		}
435 	}
436 	/*
437 	 * If this is a system packet, we don't need to
438 	 * queue it up, and won't update acknowledge #
439 	 */
440 	if (si->si_cc & SP_SP) {
441 		return (1);
442 	}
443 	/*
444 	 * We have already seen this packet, so drop.
445 	 */
446 	if (SSEQ_LT(si->si_seq, cb->s_ack)) {
447 		spp_istat.bdreas++;
448 		sppstat.spps_rcvduppack++;
449 		if (si->si_seq == cb->s_ack - 1)
450 			spp_istat.lstdup++;
451 		return (1);
452 	}
453 	/*
454 	 * Loop through all packets queued up to insert in
455 	 * appropriate sequence.
456 	 */
457 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
458 		if (si->si_seq == SI(q)->si_seq) {
459 			sppstat.spps_rcvduppack++;
460 			return (1);
461 		}
462 		if (SSEQ_LT(si->si_seq, SI(q)->si_seq)) {
463 			sppstat.spps_rcvoopack++;
464 			break;
465 		}
466 	}
467 	insque(si, q->si_prev);
468 	/*
469 	 * If this packet is urgent, inform process
470 	 */
471 	if (si->si_cc & SP_OB) {
472 		cb->s_iobc = ((char *)si)[1 + sizeof(*si)];
473 		sohasoutofband(so);
474 		cb->s_oobflags |= SF_IOOB;
475 	}
476 present:
477 #define SPINC sizeof(struct sphdr)
478 	/*
479 	 * Loop through all packets queued up to update acknowledge
480 	 * number, and present all acknowledged data to user;
481 	 * If in packet interface mode, show packet headers.
482 	 */
483 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
484 		  if (SI(q)->si_seq == cb->s_ack) {
485 			cb->s_ack++;
486 			m = dtom(q);
487 			if (SI(q)->si_cc & SP_OB) {
488 				cb->s_oobflags &= ~SF_IOOB;
489 				if (so->so_rcv.sb_cc)
490 					so->so_oobmark = so->so_rcv.sb_cc;
491 				else
492 					so->so_state |= SS_RCVATMARK;
493 			}
494 			q = q->si_prev;
495 			remque(q->si_next);
496 			wakeup = 1;
497 			sppstat.spps_rcvpack++;
498 #ifdef SF_NEWCALL
499 			if (cb->s_flags2 & SF_NEWCALL) {
500 				struct sphdr *sp = mtod(m, struct sphdr *);
501 				u_char dt = sp->sp_dt;
502 				spp_newchecks[4]++;
503 				if (dt != cb->s_rhdr.sp_dt) {
504 					struct mbuf *mm =
505 					   m_getclr(M_DONTWAIT, MT_CONTROL);
506 					spp_newchecks[0]++;
507 					if (mm != NULL) {
508 						u_short *s =
509 							mtod(mm, u_short *);
510 						cb->s_rhdr.sp_dt = dt;
511 						mm->m_len = 5; /*XXX*/
512 						s[0] = 5;
513 						s[1] = 1;
514 						*(u_char *)(&s[2]) = dt;
515 						sbappend(&so->so_rcv, mm);
516 					}
517 				}
518 				if (sp->sp_cc & SP_OB) {
519 					MCHTYPE(m, MT_OOBDATA);
520 					spp_newchecks[1]++;
521 					so->so_oobmark = 0;
522 					so->so_state &= ~SS_RCVATMARK;
523 				}
524 				if (packetp == 0) {
525 					m->m_data += SPINC;
526 					m->m_len -= SPINC;
527 					m->m_pkthdr.len -= SPINC;
528 				}
529 				if ((sp->sp_cc & SP_EM) || packetp) {
530 					sbappendrecord(&so->so_rcv, m);
531 					spp_newchecks[9]++;
532 				} else
533 					sbappend(&so->so_rcv, m);
534 			} else
535 #endif
536 			if (packetp) {
537 				sbappendrecord(&so->so_rcv, m);
538 			} else {
539 				cb->s_rhdr = *mtod(m, struct sphdr *);
540 				m->m_data += SPINC;
541 				m->m_len -= SPINC;
542 				m->m_pkthdr.len -= SPINC;
543 				sbappend(&so->so_rcv, m);
544 			}
545 		  } else
546 			break;
547 	}
548 	if (wakeup) sorwakeup(so);
549 	return (0);
550 }
551 
552 spp_ctlinput(cmd, arg)
553 	int cmd;
554 	caddr_t arg;
555 {
556 	struct ns_addr *na;
557 	extern u_char nsctlerrmap[];
558 	extern spp_abort(), spp_quench();
559 	extern struct nspcb *idp_drop();
560 	struct ns_errp *errp;
561 	struct nspcb *nsp;
562 	struct sockaddr_ns *sns;
563 	int type;
564 
565 	if (cmd < 0 || cmd > PRC_NCMDS)
566 		return;
567 	type = NS_ERR_UNREACH_HOST;
568 
569 	switch (cmd) {
570 
571 	case PRC_ROUTEDEAD:
572 		return;
573 
574 	case PRC_IFDOWN:
575 	case PRC_HOSTDEAD:
576 	case PRC_HOSTUNREACH:
577 		sns = (struct sockaddr_ns *)arg;
578 		if (sns->sns_family != AF_NS)
579 			return;
580 		na = &sns->sns_addr;
581 		break;
582 
583 	default:
584 		errp = (struct ns_errp *)arg;
585 		na = &errp->ns_err_idp.idp_dna;
586 		type = errp->ns_err_num;
587 		type = ntohs((u_short)type);
588 	}
589 	switch (type) {
590 
591 	case NS_ERR_UNREACH_HOST:
592 		ns_pcbnotify(na, (int)nsctlerrmap[cmd], spp_abort, (long) 0);
593 		break;
594 
595 	case NS_ERR_TOO_BIG:
596 	case NS_ERR_NOSOCK:
597 		nsp = ns_pcblookup(na, errp->ns_err_idp.idp_sna.x_port,
598 			NS_WILDCARD);
599 		if (nsp) {
600 			if(nsp->nsp_pcb)
601 				(void) spp_drop((struct sppcb *)nsp->nsp_pcb,
602 						(int)nsctlerrmap[cmd]);
603 			else
604 				(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
605 		}
606 		break;
607 
608 	case NS_ERR_FULLUP:
609 		ns_pcbnotify(na, 0, spp_quench, (long) 0);
610 	}
611 }
612 /*
613  * When a source quench is received, close congestion window
614  * to one packet.  We will gradually open it again as we proceed.
615  */
616 spp_quench(nsp)
617 	struct nspcb *nsp;
618 {
619 	struct sppcb *cb = nstosppcb(nsp);
620 
621 	if (cb)
622 		cb->s_cwnd = CUNIT;
623 }
624 
625 #ifdef notdef
626 int
627 spp_fixmtu(nsp)
628 register struct nspcb *nsp;
629 {
630 	register struct sppcb *cb = (struct sppcb *)(nsp->nsp_pcb);
631 	register struct mbuf *m;
632 	register struct spidp *si;
633 	struct ns_errp *ep;
634 	struct sockbuf *sb;
635 	int badseq, len;
636 	struct mbuf *firstbad, *m0;
637 
638 	if (cb) {
639 		/*
640 		 * The notification that we have sent
641 		 * too much is bad news -- we will
642 		 * have to go through queued up so far
643 		 * splitting ones which are too big and
644 		 * reassigning sequence numbers and checksums.
645 		 * we should then retransmit all packets from
646 		 * one above the offending packet to the last one
647 		 * we had sent (or our allocation)
648 		 * then the offending one so that the any queued
649 		 * data at our destination will be discarded.
650 		 */
651 		 ep = (struct ns_errp *)nsp->nsp_notify_param;
652 		 sb = &nsp->nsp_socket->so_snd;
653 		 cb->s_mtu = ep->ns_err_param;
654 		 badseq = SI(&ep->ns_err_idp)->si_seq;
655 		 for (m = sb->sb_mb; m; m = m->m_act) {
656 			si = mtod(m, struct spidp *);
657 			if (si->si_seq == badseq)
658 				break;
659 		 }
660 		 if (m == 0) return;
661 		 firstbad = m;
662 		 /*for (;;) {*/
663 			/* calculate length */
664 			for (m0 = m, len = 0; m ; m = m->m_next)
665 				len += m->m_len;
666 			if (len > cb->s_mtu) {
667 			}
668 		/* FINISH THIS
669 		} */
670 	}
671 }
672 #endif
673 
674 spp_output(cb, m0)
675 	register struct sppcb *cb;
676 	struct mbuf *m0;
677 {
678 	struct socket *so = cb->s_nspcb->nsp_socket;
679 	register struct mbuf *m;
680 	register struct spidp *si = (struct spidp *) 0;
681 	register struct sockbuf *sb = &so->so_snd;
682 	int len = 0, win, rcv_win;
683 	short span, off, recordp = 0;
684 	u_short alo;
685 	int error = 0, sendalot;
686 #ifdef notdef
687 	int idle;
688 #endif
689 	struct mbuf *mprev;
690 	extern int idpcksum;
691 
692 	if (m0) {
693 		int mtu = cb->s_mtu;
694 		int datalen;
695 		/*
696 		 * Make sure that packet isn't too big.
697 		 */
698 		for (m = m0; m ; m = m->m_next) {
699 			mprev = m;
700 			len += m->m_len;
701 			if (m->m_flags & M_EOR)
702 				recordp = 1;
703 		}
704 		datalen = (cb->s_flags & SF_HO) ?
705 				len - sizeof (struct sphdr) : len;
706 		if (datalen > mtu) {
707 			if (cb->s_flags & SF_PI) {
708 				m_freem(m0);
709 				return (EMSGSIZE);
710 			} else {
711 				int oldEM = cb->s_cc & SP_EM;
712 
713 				cb->s_cc &= ~SP_EM;
714 				while (len > mtu) {
715 					/*
716 					 * Here we are only being called
717 					 * from usrreq(), so it is OK to
718 					 * block.
719 					 */
720 					m = m_copym(m0, 0, mtu, M_WAIT);
721 					if (cb->s_flags & SF_NEWCALL) {
722 					    struct mbuf *mm = m;
723 					    spp_newchecks[7]++;
724 					    while (mm) {
725 						mm->m_flags &= ~M_EOR;
726 						mm = mm->m_next;
727 					    }
728 					}
729 					error = spp_output(cb, m);
730 					if (error) {
731 						cb->s_cc |= oldEM;
732 						m_freem(m0);
733 						return(error);
734 					}
735 					m_adj(m0, mtu);
736 					len -= mtu;
737 				}
738 				cb->s_cc |= oldEM;
739 			}
740 		}
741 		/*
742 		 * Force length even, by adding a "garbage byte" if
743 		 * necessary.
744 		 */
745 		if (len & 1) {
746 			m = mprev;
747 			if (M_TRAILINGSPACE(m) >= 1)
748 				m->m_len++;
749 			else {
750 				struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA);
751 
752 				if (m1 == 0) {
753 					m_freem(m0);
754 					return (ENOBUFS);
755 				}
756 				m1->m_len = 1;
757 				*(mtod(m1, u_char *)) = 0;
758 				m->m_next = m1;
759 			}
760 		}
761 		m = m_gethdr(M_DONTWAIT, MT_HEADER);
762 		if (m == 0) {
763 			m_freem(m0);
764 			return (ENOBUFS);
765 		}
766 		/*
767 		 * Fill in mbuf with extended SP header
768 		 * and addresses and length put into network format.
769 		 */
770 		MH_ALIGN(m, sizeof (struct spidp));
771 		m->m_len = sizeof (struct spidp);
772 		m->m_next = m0;
773 		si = mtod(m, struct spidp *);
774 		si->si_i = *cb->s_idp;
775 		si->si_s = cb->s_shdr;
776 		if ((cb->s_flags & SF_PI) && (cb->s_flags & SF_HO)) {
777 			register struct sphdr *sh;
778 			if (m0->m_len < sizeof (*sh)) {
779 				if((m0 = m_pullup(m0, sizeof(*sh))) == NULL) {
780 					(void) m_free(m);
781 					m_freem(m0);
782 					return (EINVAL);
783 				}
784 				m->m_next = m0;
785 			}
786 			sh = mtod(m0, struct sphdr *);
787 			si->si_dt = sh->sp_dt;
788 			si->si_cc |= sh->sp_cc & SP_EM;
789 			m0->m_len -= sizeof (*sh);
790 			m0->m_data += sizeof (*sh);
791 			len -= sizeof (*sh);
792 		}
793 		len += sizeof(*si);
794 		if ((cb->s_flags2 & SF_NEWCALL) && recordp) {
795 			si->si_cc  |= SP_EM;
796 			spp_newchecks[8]++;
797 		}
798 		if (cb->s_oobflags & SF_SOOB) {
799 			/*
800 			 * Per jqj@cornell:
801 			 * make sure OB packets convey exactly 1 byte.
802 			 * If the packet is 1 byte or larger, we
803 			 * have already guaranted there to be at least
804 			 * one garbage byte for the checksum, and
805 			 * extra bytes shouldn't hurt!
806 			 */
807 			if (len > sizeof(*si)) {
808 				si->si_cc |= SP_OB;
809 				len = (1 + sizeof(*si));
810 			}
811 		}
812 		si->si_len = htons((u_short)len);
813 		m->m_pkthdr.len = ((len - 1) | 1) + 1;
814 		/*
815 		 * queue stuff up for output
816 		 */
817 		sbappendrecord(sb, m);
818 		cb->s_seq++;
819 	}
820 #ifdef notdef
821 	idle = (cb->s_smax == (cb->s_rack - 1));
822 #endif
823 again:
824 	sendalot = 0;
825 	off = cb->s_snxt - cb->s_rack;
826 	win = min(cb->s_swnd, (cb->s_cwnd/CUNIT));
827 
828 	/*
829 	 * If in persist timeout with window of 0, send a probe.
830 	 * Otherwise, if window is small but nonzero
831 	 * and timer expired, send what we can and go into
832 	 * transmit state.
833 	 */
834 	if (cb->s_force == 1 + SPPT_PERSIST) {
835 		if (win != 0) {
836 			cb->s_timer[SPPT_PERSIST] = 0;
837 			cb->s_rxtshift = 0;
838 		}
839 	}
840 	span = cb->s_seq - cb->s_rack;
841 	len = min(span, win) - off;
842 
843 	if (len < 0) {
844 		/*
845 		 * Window shrank after we went into it.
846 		 * If window shrank to 0, cancel pending
847 		 * restransmission and pull s_snxt back
848 		 * to (closed) window.  We will enter persist
849 		 * state below.  If the widndow didn't close completely,
850 		 * just wait for an ACK.
851 		 */
852 		len = 0;
853 		if (win == 0) {
854 			cb->s_timer[SPPT_REXMT] = 0;
855 			cb->s_snxt = cb->s_rack;
856 		}
857 	}
858 	if (len > 1)
859 		sendalot = 1;
860 	rcv_win = sbspace(&so->so_rcv);
861 
862 	/*
863 	 * Send if we owe peer an ACK.
864 	 */
865 	if (cb->s_oobflags & SF_SOOB) {
866 		/*
867 		 * must transmit this out of band packet
868 		 */
869 		cb->s_oobflags &= ~ SF_SOOB;
870 		sendalot = 1;
871 		sppstat.spps_sndurg++;
872 		goto found;
873 	}
874 	if (cb->s_flags & SF_ACKNOW)
875 		goto send;
876 	if (cb->s_state < TCPS_ESTABLISHED)
877 		goto send;
878 	/*
879 	 * Silly window can't happen in spp.
880 	 * Code from tcp deleted.
881 	 */
882 	if (len)
883 		goto send;
884 	/*
885 	 * Compare available window to amount of window
886 	 * known to peer (as advertised window less
887 	 * next expected input.)  If the difference is at least two
888 	 * packets or at least 35% of the mximum possible window,
889 	 * then want to send a window update to peer.
890 	 */
891 	if (rcv_win > 0) {
892 		u_short delta =  1 + cb->s_alo - cb->s_ack;
893 		int adv = rcv_win - (delta * cb->s_mtu);
894 
895 		if ((so->so_rcv.sb_cc == 0 && adv >= (2 * cb->s_mtu)) ||
896 		    (100 * adv / so->so_rcv.sb_hiwat >= 35)) {
897 			sppstat.spps_sndwinup++;
898 			cb->s_flags |= SF_ACKNOW;
899 			goto send;
900 		}
901 
902 	}
903 	/*
904 	 * Many comments from tcp_output.c are appropriate here
905 	 * including . . .
906 	 * If send window is too small, there is data to transmit, and no
907 	 * retransmit or persist is pending, then go to persist state.
908 	 * If nothing happens soon, send when timer expires:
909 	 * if window is nonzero, transmit what we can,
910 	 * otherwise send a probe.
911 	 */
912 	if (so->so_snd.sb_cc && cb->s_timer[SPPT_REXMT] == 0 &&
913 		cb->s_timer[SPPT_PERSIST] == 0) {
914 			cb->s_rxtshift = 0;
915 			spp_setpersist(cb);
916 	}
917 	/*
918 	 * No reason to send a packet, just return.
919 	 */
920 	cb->s_outx = 1;
921 	return (0);
922 
923 send:
924 	/*
925 	 * Find requested packet.
926 	 */
927 	si = 0;
928 	if (len > 0) {
929 		cb->s_want = cb->s_snxt;
930 		for (m = sb->sb_mb; m; m = m->m_act) {
931 			si = mtod(m, struct spidp *);
932 			if (SSEQ_LEQ(cb->s_snxt, si->si_seq))
933 				break;
934 		}
935 	found:
936 		if (si) {
937 			if (si->si_seq == cb->s_snxt)
938 					cb->s_snxt++;
939 				else
940 					sppstat.spps_sndvoid++, si = 0;
941 		}
942 	}
943 	/*
944 	 * update window
945 	 */
946 	if (rcv_win < 0)
947 		rcv_win = 0;
948 	alo = cb->s_ack - 1 + (rcv_win / ((short)cb->s_mtu));
949 	if (SSEQ_LT(alo, cb->s_alo))
950 		alo = cb->s_alo;
951 
952 	if (si) {
953 		/*
954 		 * must make a copy of this packet for
955 		 * idp_output to monkey with
956 		 */
957 		m = m_copy(dtom(si), 0, (int)M_COPYALL);
958 		if (m == NULL) {
959 			return (ENOBUFS);
960 		}
961 		si = mtod(m, struct spidp *);
962 		if (SSEQ_LT(si->si_seq, cb->s_smax))
963 			sppstat.spps_sndrexmitpack++;
964 		else
965 			sppstat.spps_sndpack++;
966 	} else if (cb->s_force || cb->s_flags & SF_ACKNOW) {
967 		/*
968 		 * Must send an acknowledgement or a probe
969 		 */
970 		if (cb->s_force)
971 			sppstat.spps_sndprobe++;
972 		if (cb->s_flags & SF_ACKNOW)
973 			sppstat.spps_sndacks++;
974 		m = m_gethdr(M_DONTWAIT, MT_HEADER);
975 		if (m == 0)
976 			return (ENOBUFS);
977 		/*
978 		 * Fill in mbuf with extended SP header
979 		 * and addresses and length put into network format.
980 		 */
981 		MH_ALIGN(m, sizeof (struct spidp));
982 		m->m_len = sizeof (*si);
983 		m->m_pkthdr.len = sizeof (*si);
984 		si = mtod(m, struct spidp *);
985 		si->si_i = *cb->s_idp;
986 		si->si_s = cb->s_shdr;
987 		si->si_seq = cb->s_smax + 1;
988 		si->si_len = htons(sizeof (*si));
989 		si->si_cc |= SP_SP;
990 	} else {
991 		cb->s_outx = 3;
992 		if (so->so_options & SO_DEBUG || traceallspps)
993 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
994 		return (0);
995 	}
996 	/*
997 	 * Stuff checksum and output datagram.
998 	 */
999 	if ((si->si_cc & SP_SP) == 0) {
1000 		if (cb->s_force != (1 + SPPT_PERSIST) ||
1001 		    cb->s_timer[SPPT_PERSIST] == 0) {
1002 			/*
1003 			 * If this is a new packet and we are not currently
1004 			 * timing anything, time this one.
1005 			 */
1006 			if (SSEQ_LT(cb->s_smax, si->si_seq)) {
1007 				cb->s_smax = si->si_seq;
1008 				if (cb->s_rtt == 0) {
1009 					sppstat.spps_segstimed++;
1010 					cb->s_rtseq = si->si_seq;
1011 					cb->s_rtt = 1;
1012 				}
1013 			}
1014 			/*
1015 			 * Set rexmt timer if not currently set,
1016 			 * Initial value for retransmit timer is smoothed
1017 			 * round-trip time + 2 * round-trip time variance.
1018 			 * Initialize shift counter which is used for backoff
1019 			 * of retransmit time.
1020 			 */
1021 			if (cb->s_timer[SPPT_REXMT] == 0 &&
1022 			    cb->s_snxt != cb->s_rack) {
1023 				cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
1024 				if (cb->s_timer[SPPT_PERSIST]) {
1025 					cb->s_timer[SPPT_PERSIST] = 0;
1026 					cb->s_rxtshift = 0;
1027 				}
1028 			}
1029 		} else if (SSEQ_LT(cb->s_smax, si->si_seq)) {
1030 			cb->s_smax = si->si_seq;
1031 		}
1032 	} else if (cb->s_state < TCPS_ESTABLISHED) {
1033 		if (cb->s_rtt == 0)
1034 			cb->s_rtt = 1; /* Time initial handshake */
1035 		if (cb->s_timer[SPPT_REXMT] == 0)
1036 			cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
1037 	}
1038 	{
1039 		/*
1040 		 * Do not request acks when we ack their data packets or
1041 		 * when we do a gratuitous window update.
1042 		 */
1043 		if (((si->si_cc & SP_SP) == 0) || cb->s_force)
1044 				si->si_cc |= SP_SA;
1045 		si->si_seq = htons(si->si_seq);
1046 		si->si_alo = htons(alo);
1047 		si->si_ack = htons(cb->s_ack);
1048 
1049 		if (idpcksum) {
1050 			si->si_sum = 0;
1051 			len = ntohs(si->si_len);
1052 			if (len & 1)
1053 				len++;
1054 			si->si_sum = ns_cksum(m, len);
1055 		} else
1056 			si->si_sum = 0xffff;
1057 
1058 		cb->s_outx = 4;
1059 		if (so->so_options & SO_DEBUG || traceallspps)
1060 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
1061 
1062 		if (so->so_options & SO_DONTROUTE)
1063 			error = ns_output(m, (struct route *)0, NS_ROUTETOIF);
1064 		else
1065 			error = ns_output(m, &cb->s_nspcb->nsp_route, 0);
1066 	}
1067 	if (error) {
1068 		return (error);
1069 	}
1070 	sppstat.spps_sndtotal++;
1071 	/*
1072 	 * Data sent (as far as we can tell).
1073 	 * If this advertises a larger window than any other segment,
1074 	 * then remember the size of the advertized window.
1075 	 * Any pending ACK has now been sent.
1076 	 */
1077 	cb->s_force = 0;
1078 	cb->s_flags &= ~(SF_ACKNOW|SF_DELACK);
1079 	if (SSEQ_GT(alo, cb->s_alo))
1080 		cb->s_alo = alo;
1081 	if (sendalot)
1082 		goto again;
1083 	cb->s_outx = 5;
1084 	return (0);
1085 }
1086 
1087 int spp_do_persist_panics = 0;
1088 
1089 spp_setpersist(cb)
1090 	register struct sppcb *cb;
1091 {
1092 	register t = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1093 	extern int spp_backoff[];
1094 
1095 	if (cb->s_timer[SPPT_REXMT] && spp_do_persist_panics)
1096 		panic("spp_output REXMT");
1097 	/*
1098 	 * Start/restart persistance timer.
1099 	 */
1100 	SPPT_RANGESET(cb->s_timer[SPPT_PERSIST],
1101 	    t*spp_backoff[cb->s_rxtshift],
1102 	    SPPTV_PERSMIN, SPPTV_PERSMAX);
1103 	if (cb->s_rxtshift < SPP_MAXRXTSHIFT)
1104 		cb->s_rxtshift++;
1105 }
1106 /*ARGSUSED*/
1107 spp_ctloutput(req, so, level, name, value)
1108 	int req;
1109 	struct socket *so;
1110 	int name;
1111 	struct mbuf **value;
1112 {
1113 	register struct mbuf *m;
1114 	struct nspcb *nsp = sotonspcb(so);
1115 	register struct sppcb *cb;
1116 	int mask, error = 0;
1117 
1118 	if (level != NSPROTO_SPP) {
1119 		/* This will have to be changed when we do more general
1120 		   stacking of protocols */
1121 		return (idp_ctloutput(req, so, level, name, value));
1122 	}
1123 	if (nsp == NULL) {
1124 		error = EINVAL;
1125 		goto release;
1126 	} else
1127 		cb = nstosppcb(nsp);
1128 
1129 	switch (req) {
1130 
1131 	case PRCO_GETOPT:
1132 		if (value == NULL)
1133 			return (EINVAL);
1134 		m = m_get(M_DONTWAIT, MT_DATA);
1135 		if (m == NULL)
1136 			return (ENOBUFS);
1137 		switch (name) {
1138 
1139 		case SO_HEADERS_ON_INPUT:
1140 			mask = SF_HI;
1141 			goto get_flags;
1142 
1143 		case SO_HEADERS_ON_OUTPUT:
1144 			mask = SF_HO;
1145 		get_flags:
1146 			m->m_len = sizeof(short);
1147 			*mtod(m, short *) = cb->s_flags & mask;
1148 			break;
1149 
1150 		case SO_MTU:
1151 			m->m_len = sizeof(u_short);
1152 			*mtod(m, short *) = cb->s_mtu;
1153 			break;
1154 
1155 		case SO_LAST_HEADER:
1156 			m->m_len = sizeof(struct sphdr);
1157 			*mtod(m, struct sphdr *) = cb->s_rhdr;
1158 			break;
1159 
1160 		case SO_DEFAULT_HEADERS:
1161 			m->m_len = sizeof(struct spidp);
1162 			*mtod(m, struct sphdr *) = cb->s_shdr;
1163 			break;
1164 
1165 		default:
1166 			error = EINVAL;
1167 		}
1168 		*value = m;
1169 		break;
1170 
1171 	case PRCO_SETOPT:
1172 		if (value == 0 || *value == 0) {
1173 			error = EINVAL;
1174 			break;
1175 		}
1176 		switch (name) {
1177 			int *ok;
1178 
1179 		case SO_HEADERS_ON_INPUT:
1180 			mask = SF_HI;
1181 			goto set_head;
1182 
1183 		case SO_HEADERS_ON_OUTPUT:
1184 			mask = SF_HO;
1185 		set_head:
1186 			if (cb->s_flags & SF_PI) {
1187 				ok = mtod(*value, int *);
1188 				if (*ok)
1189 					cb->s_flags |= mask;
1190 				else
1191 					cb->s_flags &= ~mask;
1192 			} else error = EINVAL;
1193 			break;
1194 
1195 		case SO_MTU:
1196 			cb->s_mtu = *(mtod(*value, u_short *));
1197 			break;
1198 
1199 #ifdef SF_NEWCALL
1200 		case SO_NEWCALL:
1201 			ok = mtod(*value, int *);
1202 			if (*ok) {
1203 				cb->s_flags2 |= SF_NEWCALL;
1204 				spp_newchecks[5]++;
1205 			} else {
1206 				cb->s_flags2 &= ~SF_NEWCALL;
1207 				spp_newchecks[6]++;
1208 			}
1209 			break;
1210 #endif
1211 
1212 		case SO_DEFAULT_HEADERS:
1213 			{
1214 				register struct sphdr *sp
1215 						= mtod(*value, struct sphdr *);
1216 				cb->s_dt = sp->sp_dt;
1217 				cb->s_cc = sp->sp_cc & SP_EM;
1218 			}
1219 			break;
1220 
1221 		default:
1222 			error = EINVAL;
1223 		}
1224 		m_freem(*value);
1225 		break;
1226 	}
1227 	release:
1228 		return (error);
1229 }
1230 
1231 /*ARGSUSED*/
1232 spp_usrreq(so, req, m, nam, controlp)
1233 	struct socket *so;
1234 	int req;
1235 	struct mbuf *m, *nam, *controlp;
1236 {
1237 	struct nspcb *nsp = sotonspcb(so);
1238 	register struct sppcb *cb;
1239 	int s = splnet();
1240 	int error = 0, ostate;
1241 	struct mbuf *mm;
1242 	register struct sockbuf *sb;
1243 
1244 	if (req == PRU_CONTROL)
1245                 return (ns_control(so, (int)m, (caddr_t)nam,
1246 			(struct ifnet *)controlp));
1247 	if (nsp == NULL) {
1248 		if (req != PRU_ATTACH) {
1249 			error = EINVAL;
1250 			goto release;
1251 		}
1252 	} else
1253 		cb = nstosppcb(nsp);
1254 
1255 	ostate = cb ? cb->s_state : 0;
1256 
1257 	switch (req) {
1258 
1259 	case PRU_ATTACH:
1260 		if (nsp != NULL) {
1261 			error = EISCONN;
1262 			break;
1263 		}
1264 		error = ns_pcballoc(so, &nspcb);
1265 		if (error)
1266 			break;
1267 		if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
1268 			error = soreserve(so, (u_long) 3072, (u_long) 3072);
1269 			if (error)
1270 				break;
1271 		}
1272 		nsp = sotonspcb(so);
1273 
1274 		mm = m_getclr(M_DONTWAIT, MT_PCB);
1275 		sb = &so->so_snd;
1276 
1277 		if (mm == NULL) {
1278 			error = ENOBUFS;
1279 			break;
1280 		}
1281 		cb = mtod(mm, struct sppcb *);
1282 		mm = m_getclr(M_DONTWAIT, MT_HEADER);
1283 		if (mm == NULL) {
1284 			(void) m_free(dtom(m));
1285 			error = ENOBUFS;
1286 			break;
1287 		}
1288 		cb->s_idp = mtod(mm, struct idp *);
1289 		cb->s_state = TCPS_LISTEN;
1290 		cb->s_smax = -1;
1291 		cb->s_swl1 = -1;
1292 		cb->s_q.si_next = cb->s_q.si_prev = &cb->s_q;
1293 		cb->s_nspcb = nsp;
1294 		cb->s_mtu = 576 - sizeof (struct spidp);
1295 		cb->s_cwnd = sbspace(sb) * CUNIT / cb->s_mtu;
1296 		cb->s_ssthresh = cb->s_cwnd;
1297 		cb->s_cwmx = sbspace(sb) * CUNIT /
1298 				(2 * sizeof (struct spidp));
1299 		/* Above is recomputed when connecting to account
1300 		   for changed buffering or mtu's */
1301 		cb->s_rtt = SPPTV_SRTTBASE;
1302 		cb->s_rttvar = SPPTV_SRTTDFLT << 2;
1303 		SPPT_RANGESET(cb->s_rxtcur,
1304 		    ((SPPTV_SRTTBASE >> 2) + (SPPTV_SRTTDFLT << 2)) >> 1,
1305 		    SPPTV_MIN, SPPTV_REXMTMAX);
1306 		nsp->nsp_pcb = (caddr_t) cb;
1307 		break;
1308 
1309 	case PRU_DETACH:
1310 		if (nsp == NULL) {
1311 			error = ENOTCONN;
1312 			break;
1313 		}
1314 		if (cb->s_state > TCPS_LISTEN)
1315 			cb = spp_disconnect(cb);
1316 		else
1317 			cb = spp_close(cb);
1318 		break;
1319 
1320 	case PRU_BIND:
1321 		error = ns_pcbbind(nsp, nam);
1322 		break;
1323 
1324 	case PRU_LISTEN:
1325 		if (nsp->nsp_lport == 0)
1326 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1327 		if (error == 0)
1328 			cb->s_state = TCPS_LISTEN;
1329 		break;
1330 
1331 	/*
1332 	 * Initiate connection to peer.
1333 	 * Enter SYN_SENT state, and mark socket as connecting.
1334 	 * Start keep-alive timer, setup prototype header,
1335 	 * Send initial system packet requesting connection.
1336 	 */
1337 	case PRU_CONNECT:
1338 		if (nsp->nsp_lport == 0) {
1339 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1340 			if (error)
1341 				break;
1342 		}
1343 		error = ns_pcbconnect(nsp, nam);
1344 		if (error)
1345 			break;
1346 		soisconnecting(so);
1347 		sppstat.spps_connattempt++;
1348 		cb->s_state = TCPS_SYN_SENT;
1349 		cb->s_did = 0;
1350 		spp_template(cb);
1351 		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
1352 		cb->s_force = 1 + SPPTV_KEEP;
1353 		/*
1354 		 * Other party is required to respond to
1355 		 * the port I send from, but he is not
1356 		 * required to answer from where I am sending to,
1357 		 * so allow wildcarding.
1358 		 * original port I am sending to is still saved in
1359 		 * cb->s_dport.
1360 		 */
1361 		nsp->nsp_fport = 0;
1362 		error = spp_output(cb, (struct mbuf *) 0);
1363 		break;
1364 
1365 	case PRU_CONNECT2:
1366 		error = EOPNOTSUPP;
1367 		break;
1368 
1369 	/*
1370 	 * We may decide later to implement connection closing
1371 	 * handshaking at the spp level optionally.
1372 	 * here is the hook to do it:
1373 	 */
1374 	case PRU_DISCONNECT:
1375 		cb = spp_disconnect(cb);
1376 		break;
1377 
1378 	/*
1379 	 * Accept a connection.  Essentially all the work is
1380 	 * done at higher levels; just return the address
1381 	 * of the peer, storing through addr.
1382 	 */
1383 	case PRU_ACCEPT: {
1384 		struct sockaddr_ns *sns = mtod(nam, struct sockaddr_ns *);
1385 
1386 		nam->m_len = sizeof (struct sockaddr_ns);
1387 		sns->sns_family = AF_NS;
1388 		sns->sns_addr = nsp->nsp_faddr;
1389 		break;
1390 		}
1391 
1392 	case PRU_SHUTDOWN:
1393 		socantsendmore(so);
1394 		cb = spp_usrclosed(cb);
1395 		if (cb)
1396 			error = spp_output(cb, (struct mbuf *) 0);
1397 		break;
1398 
1399 	/*
1400 	 * After a receive, possibly send acknowledgment
1401 	 * updating allocation.
1402 	 */
1403 	case PRU_RCVD:
1404 		cb->s_flags |= SF_RVD;
1405 		(void) spp_output(cb, (struct mbuf *) 0);
1406 		cb->s_flags &= ~SF_RVD;
1407 		break;
1408 
1409 	case PRU_ABORT:
1410 		(void) spp_drop(cb, ECONNABORTED);
1411 		break;
1412 
1413 	case PRU_SENSE:
1414 	case PRU_CONTROL:
1415 		m = NULL;
1416 		error = EOPNOTSUPP;
1417 		break;
1418 
1419 	case PRU_RCVOOB:
1420 		if ((cb->s_oobflags & SF_IOOB) || so->so_oobmark ||
1421 		    (so->so_state & SS_RCVATMARK)) {
1422 			m->m_len = 1;
1423 			*mtod(m, caddr_t) = cb->s_iobc;
1424 			break;
1425 		}
1426 		error = EINVAL;
1427 		break;
1428 
1429 	case PRU_SENDOOB:
1430 		if (sbspace(&so->so_snd) < -512) {
1431 			error = ENOBUFS;
1432 			break;
1433 		}
1434 		cb->s_oobflags |= SF_SOOB;
1435 		/* fall into */
1436 	case PRU_SEND:
1437 		if (controlp) {
1438 			u_short *p = mtod(controlp, u_short *);
1439 			spp_newchecks[2]++;
1440 			if ((p[0] == 5) && p[1] == 1) { /* XXXX, for testing */
1441 				cb->s_shdr.sp_dt = *(u_char *)(&p[2]);
1442 				spp_newchecks[3]++;
1443 			}
1444 			m_freem(controlp);
1445 		}
1446 		controlp = NULL;
1447 		error = spp_output(cb, m);
1448 		m = NULL;
1449 		break;
1450 
1451 	case PRU_SOCKADDR:
1452 		ns_setsockaddr(nsp, nam);
1453 		break;
1454 
1455 	case PRU_PEERADDR:
1456 		ns_setpeeraddr(nsp, nam);
1457 		break;
1458 
1459 	case PRU_SLOWTIMO:
1460 		cb = spp_timers(cb, (int)nam);
1461 		req |= ((int)nam) << 8;
1462 		break;
1463 
1464 	case PRU_FASTTIMO:
1465 	case PRU_PROTORCV:
1466 	case PRU_PROTOSEND:
1467 		error =  EOPNOTSUPP;
1468 		break;
1469 
1470 	default:
1471 		panic("sp_usrreq");
1472 	}
1473 	if (cb && (so->so_options & SO_DEBUG || traceallspps))
1474 		spp_trace(SA_USER, (u_char)ostate, cb, (struct spidp *)0, req);
1475 release:
1476 	if (controlp != NULL)
1477 		m_freem(controlp);
1478 	if (m != NULL)
1479 		m_freem(m);
1480 	splx(s);
1481 	return (error);
1482 }
1483 
1484 spp_usrreq_sp(so, req, m, nam, controlp)
1485 	struct socket *so;
1486 	int req;
1487 	struct mbuf *m, *nam, *controlp;
1488 {
1489 	int error = spp_usrreq(so, req, m, nam, controlp);
1490 
1491 	if (req == PRU_ATTACH && error == 0) {
1492 		struct nspcb *nsp = sotonspcb(so);
1493 		((struct sppcb *)nsp->nsp_pcb)->s_flags |=
1494 					(SF_HI | SF_HO | SF_PI);
1495 	}
1496 	return (error);
1497 }
1498 
1499 /*
1500  * Create template to be used to send spp packets on a connection.
1501  * Called after host entry created, fills
1502  * in a skeletal spp header (choosing connection id),
1503  * minimizing the amount of work necessary when the connection is used.
1504  */
1505 spp_template(cb)
1506 	register struct sppcb *cb;
1507 {
1508 	register struct nspcb *nsp = cb->s_nspcb;
1509 	register struct idp *idp = cb->s_idp;
1510 	register struct sockbuf *sb = &(nsp->nsp_socket->so_snd);
1511 
1512 	idp->idp_pt = NSPROTO_SPP;
1513 	idp->idp_sna = nsp->nsp_laddr;
1514 	idp->idp_dna = nsp->nsp_faddr;
1515 	cb->s_sid = htons(spp_iss);
1516 	spp_iss += SPP_ISSINCR/2;
1517 	cb->s_alo = 1;
1518 	cb->s_cwnd = (sbspace(sb) * CUNIT) / cb->s_mtu;
1519 	cb->s_ssthresh = cb->s_cwnd; /* Try to expand fast to full complement
1520 					of large packets */
1521 	cb->s_cwmx = (sbspace(sb) * CUNIT) / (2 * sizeof(struct spidp));
1522 	cb->s_cwmx = max(cb->s_cwmx, cb->s_cwnd);
1523 		/* But allow for lots of little packets as well */
1524 }
1525 
1526 /*
1527  * Close a SPIP control block:
1528  *	discard spp control block itself
1529  *	discard ns protocol control block
1530  *	wake up any sleepers
1531  */
1532 struct sppcb *
1533 spp_close(cb)
1534 	register struct sppcb *cb;
1535 {
1536 	register struct spidp_q *s;
1537 	struct nspcb *nsp = cb->s_nspcb;
1538 	struct socket *so = nsp->nsp_socket;
1539 	register struct mbuf *m;
1540 
1541 	s = cb->s_q.si_next;
1542 	while (s != &(cb->s_q)) {
1543 		s = s->si_next;
1544 		m = dtom(s->si_prev);
1545 		remque(s->si_prev);
1546 		m_freem(m);
1547 	}
1548 	(void) m_free(dtom(cb->s_idp));
1549 	(void) m_free(dtom(cb));
1550 	nsp->nsp_pcb = 0;
1551 	soisdisconnected(so);
1552 	ns_pcbdetach(nsp);
1553 	sppstat.spps_closed++;
1554 	return ((struct sppcb *)0);
1555 }
1556 /*
1557  *	Someday we may do level 3 handshaking
1558  *	to close a connection or send a xerox style error.
1559  *	For now, just close.
1560  */
1561 struct sppcb *
1562 spp_usrclosed(cb)
1563 	register struct sppcb *cb;
1564 {
1565 	return (spp_close(cb));
1566 }
1567 struct sppcb *
1568 spp_disconnect(cb)
1569 	register struct sppcb *cb;
1570 {
1571 	return (spp_close(cb));
1572 }
1573 /*
1574  * Drop connection, reporting
1575  * the specified error.
1576  */
1577 struct sppcb *
1578 spp_drop(cb, errno)
1579 	register struct sppcb *cb;
1580 	int errno;
1581 {
1582 	struct socket *so = cb->s_nspcb->nsp_socket;
1583 
1584 	/*
1585 	 * someday, in the xerox world
1586 	 * we will generate error protocol packets
1587 	 * announcing that the socket has gone away.
1588 	 */
1589 	if (TCPS_HAVERCVDSYN(cb->s_state)) {
1590 		sppstat.spps_drops++;
1591 		cb->s_state = TCPS_CLOSED;
1592 		/*(void) tcp_output(cb);*/
1593 	} else
1594 		sppstat.spps_conndrops++;
1595 	so->so_error = errno;
1596 	return (spp_close(cb));
1597 }
1598 
1599 spp_abort(nsp)
1600 	struct nspcb *nsp;
1601 {
1602 
1603 	(void) spp_close((struct sppcb *)nsp->nsp_pcb);
1604 }
1605 
1606 int	spp_backoff[SPP_MAXRXTSHIFT+1] =
1607     { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
1608 /*
1609  * Fast timeout routine for processing delayed acks
1610  */
1611 spp_fasttimo()
1612 {
1613 	register struct nspcb *nsp;
1614 	register struct sppcb *cb;
1615 	int s = splnet();
1616 
1617 	nsp = nspcb.nsp_next;
1618 	if (nsp)
1619 	for (; nsp != &nspcb; nsp = nsp->nsp_next)
1620 		if ((cb = (struct sppcb *)nsp->nsp_pcb) &&
1621 		    (cb->s_flags & SF_DELACK)) {
1622 			cb->s_flags &= ~SF_DELACK;
1623 			cb->s_flags |= SF_ACKNOW;
1624 			sppstat.spps_delack++;
1625 			(void) spp_output(cb, (struct mbuf *) 0);
1626 		}
1627 	splx(s);
1628 }
1629 
1630 /*
1631  * spp protocol timeout routine called every 500 ms.
1632  * Updates the timers in all active pcb's and
1633  * causes finite state machine actions if timers expire.
1634  */
1635 spp_slowtimo()
1636 {
1637 	register struct nspcb *ip, *ipnxt;
1638 	register struct sppcb *cb;
1639 	int s = splnet();
1640 	register int i;
1641 
1642 	/*
1643 	 * Search through tcb's and update active timers.
1644 	 */
1645 	ip = nspcb.nsp_next;
1646 	if (ip == 0) {
1647 		splx(s);
1648 		return;
1649 	}
1650 	while (ip != &nspcb) {
1651 		cb = nstosppcb(ip);
1652 		ipnxt = ip->nsp_next;
1653 		if (cb == 0)
1654 			goto tpgone;
1655 		for (i = 0; i < SPPT_NTIMERS; i++) {
1656 			if (cb->s_timer[i] && --cb->s_timer[i] == 0) {
1657 				(void) spp_usrreq(cb->s_nspcb->nsp_socket,
1658 				    PRU_SLOWTIMO, (struct mbuf *)0,
1659 				    (struct mbuf *)i, (struct mbuf *)0,
1660 				    (struct mbuf *)0);
1661 				if (ipnxt->nsp_prev != ip)
1662 					goto tpgone;
1663 			}
1664 		}
1665 		cb->s_idle++;
1666 		if (cb->s_rtt)
1667 			cb->s_rtt++;
1668 tpgone:
1669 		ip = ipnxt;
1670 	}
1671 	spp_iss += SPP_ISSINCR/PR_SLOWHZ;		/* increment iss */
1672 	splx(s);
1673 }
1674 /*
1675  * SPP timer processing.
1676  */
1677 struct sppcb *
1678 spp_timers(cb, timer)
1679 	register struct sppcb *cb;
1680 	int timer;
1681 {
1682 	long rexmt;
1683 	int win;
1684 
1685 	cb->s_force = 1 + timer;
1686 	switch (timer) {
1687 
1688 	/*
1689 	 * 2 MSL timeout in shutdown went off.  TCP deletes connection
1690 	 * control block.
1691 	 */
1692 	case SPPT_2MSL:
1693 		printf("spp: SPPT_2MSL went off for no reason\n");
1694 		cb->s_timer[timer] = 0;
1695 		break;
1696 
1697 	/*
1698 	 * Retransmission timer went off.  Message has not
1699 	 * been acked within retransmit interval.  Back off
1700 	 * to a longer retransmit interval and retransmit one packet.
1701 	 */
1702 	case SPPT_REXMT:
1703 		if (++cb->s_rxtshift > SPP_MAXRXTSHIFT) {
1704 			cb->s_rxtshift = SPP_MAXRXTSHIFT;
1705 			sppstat.spps_timeoutdrop++;
1706 			cb = spp_drop(cb, ETIMEDOUT);
1707 			break;
1708 		}
1709 		sppstat.spps_rexmttimeo++;
1710 		rexmt = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1711 		rexmt *= spp_backoff[cb->s_rxtshift];
1712 		SPPT_RANGESET(cb->s_rxtcur, rexmt, SPPTV_MIN, SPPTV_REXMTMAX);
1713 		cb->s_timer[SPPT_REXMT] = cb->s_rxtcur;
1714 		/*
1715 		 * If we have backed off fairly far, our srtt
1716 		 * estimate is probably bogus.  Clobber it
1717 		 * so we'll take the next rtt measurement as our srtt;
1718 		 * move the current srtt into rttvar to keep the current
1719 		 * retransmit times until then.
1720 		 */
1721 		if (cb->s_rxtshift > SPP_MAXRXTSHIFT / 4 ) {
1722 			cb->s_rttvar += (cb->s_srtt >> 2);
1723 			cb->s_srtt = 0;
1724 		}
1725 		cb->s_snxt = cb->s_rack;
1726 		/*
1727 		 * If timing a packet, stop the timer.
1728 		 */
1729 		cb->s_rtt = 0;
1730 		/*
1731 		 * See very long discussion in tcp_timer.c about congestion
1732 		 * window and sstrhesh
1733 		 */
1734 		win = min(cb->s_swnd, (cb->s_cwnd/CUNIT)) / 2;
1735 		if (win < 2)
1736 			win = 2;
1737 		cb->s_cwnd = CUNIT;
1738 		cb->s_ssthresh = win * CUNIT;
1739 		(void) spp_output(cb, (struct mbuf *) 0);
1740 		break;
1741 
1742 	/*
1743 	 * Persistance timer into zero window.
1744 	 * Force a probe to be sent.
1745 	 */
1746 	case SPPT_PERSIST:
1747 		sppstat.spps_persisttimeo++;
1748 		spp_setpersist(cb);
1749 		(void) spp_output(cb, (struct mbuf *) 0);
1750 		break;
1751 
1752 	/*
1753 	 * Keep-alive timer went off; send something
1754 	 * or drop connection if idle for too long.
1755 	 */
1756 	case SPPT_KEEP:
1757 		sppstat.spps_keeptimeo++;
1758 		if (cb->s_state < TCPS_ESTABLISHED)
1759 			goto dropit;
1760 		if (cb->s_nspcb->nsp_socket->so_options & SO_KEEPALIVE) {
1761 		    	if (cb->s_idle >= SPPTV_MAXIDLE)
1762 				goto dropit;
1763 			sppstat.spps_keepprobe++;
1764 			(void) spp_output(cb, (struct mbuf *) 0);
1765 		} else
1766 			cb->s_idle = 0;
1767 		cb->s_timer[SPPT_KEEP] = SPPTV_KEEP;
1768 		break;
1769 	dropit:
1770 		sppstat.spps_keepdrops++;
1771 		cb = spp_drop(cb, ETIMEDOUT);
1772 		break;
1773 	}
1774 	return (cb);
1775 }
1776 #ifndef lint
1777 int SppcbSize = sizeof (struct sppcb);
1778 int NspcbSize = sizeof (struct nspcb);
1779 #endif lint
1780