xref: /csrg-svn/sys/netns/spp_usrreq.c (revision 33637)
1 /*
2  * Copyright (c) 1984, 1985, 1986, 1987 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that this notice is preserved and that due credit is given
7  * to the University of California at Berkeley. The name of the University
8  * may not be used to endorse or promote products derived from this
9  * software without specific prior written permission. This software
10  * is provided ``as is'' without express or implied warranty.
11  *
12  *      @(#)spp_usrreq.c	7.5 (Berkeley) 03/03/88
13  */
14 
15 #include "param.h"
16 #include "systm.h"
17 #include "dir.h"
18 #include "user.h"
19 #include "mbuf.h"
20 #include "protosw.h"
21 #include "socket.h"
22 #include "socketvar.h"
23 #include "errno.h"
24 
25 #include "../net/if.h"
26 #include "../net/route.h"
27 #include "../netinet/tcp_fsm.h"
28 #include "../netinet/tcp_timer.h"
29 
30 #include "ns.h"
31 #include "ns_pcb.h"
32 #include "idp.h"
33 #include "idp_var.h"
34 #include "ns_error.h"
35 #include "sp.h"
36 #include "spidp.h"
37 #include "spp_var.h"
38 #include "spp_debug.h"
39 
40 /*
41  * SP protocol implementation.
42  */
43 spp_init()
44 {
45 
46 	spp_iss = 1; /* WRONG !! should fish it out of TODR */
47 }
48 struct spidp spp_savesi;
49 int traceallspps = 0;
50 extern int sppconsdebug;
51 int spp_hardnosed;
52 int spp_use_delack = 0;
53 
54 /*ARGSUSED*/
55 spp_input(m, nsp, ifp)
56 	register struct mbuf *m;
57 	register struct nspcb *nsp;
58 	struct ifnet *ifp;
59 {
60 	register struct sppcb *cb;
61 	register struct spidp *si = mtod(m, struct spidp *);
62 	register struct socket *so;
63 	short ostate;
64 	int dropsocket = 0;
65 
66 
67 	sppstat.spps_rcvtotal++;
68 	if (nsp == 0) {
69 		panic("No nspcb in spp_input\n");
70 		return;
71 	}
72 
73 	cb = nstosppcb(nsp);
74 	if (cb == 0) goto bad;
75 
76 	if (m->m_len < sizeof(*si)) {
77 		if ((m = m_pullup(m, sizeof(*si))) == 0) {
78 			sppstat.spps_rcvshort++;
79 			return;
80 		}
81 		si = mtod(m, struct spidp *);
82 	}
83 	si->si_seq = ntohs(si->si_seq);
84 	si->si_ack = ntohs(si->si_ack);
85 	si->si_alo = ntohs(si->si_alo);
86 
87 	so = nsp->nsp_socket;
88 	if (so->so_options & SO_DEBUG || traceallspps) {
89 		ostate = cb->s_state;
90 		spp_savesi = *si;
91 	}
92 	if (so->so_options & SO_ACCEPTCONN) {
93 		struct sppcb *ocb = cb;
94 		struct socket *oso = so;
95 		so = sonewconn(so);
96 		if (so == 0) {
97 			goto drop;
98 		}
99 		/*
100 		 * This is ugly, but ....
101 		 *
102 		 * Mark socket as temporary until we're
103 		 * committed to keeping it.  The code at
104 		 * ``drop'' and ``dropwithreset'' check the
105 		 * flag dropsocket to see if the temporary
106 		 * socket created here should be discarded.
107 		 * We mark the socket as discardable until
108 		 * we're committed to it below in TCPS_LISTEN.
109 		 */
110 		dropsocket++;
111 		nsp = (struct nspcb *)so->so_pcb;
112 		nsp->nsp_laddr = si->si_dna;
113 		cb = nstosppcb(nsp);
114 		cb->s_mtu = ocb->s_mtu;		/* preserve sockopts */
115 		cb->s_flags = ocb->s_flags;	/* preserve sockopts */
116 		if (so->so_snd.sb_hiwat != oso->so_snd.sb_hiwat) /*XXX*/
117 			sbreserve(&so->so_snd, oso->so_snd.sb_hiwat);
118 		if (so->so_rcv.sb_hiwat != oso->so_rcv.sb_hiwat) /*XXX*/
119 			sbreserve(&so->so_rcv, oso->so_rcv.sb_hiwat);
120 		cb->s_state = TCPS_LISTEN;
121 	}
122 
123 	/*
124 	 * Packet received on connection.
125 	 * reset idle time and keep-alive timer;
126 	 */
127 	cb->s_idle = 0;
128 	cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
129 
130 	switch (cb->s_state) {
131 
132 	case TCPS_LISTEN:{
133 		struct mbuf *am;
134 		register struct sockaddr_ns *sns;
135 		struct ns_addr laddr;
136 
137 		/*
138 		 * If somebody here was carying on a conversation
139 		 * and went away, and his pen pal thinks he can
140 		 * still talk, we get the misdirected packet.
141 		 */
142 		if (spp_hardnosed && (si->si_did != 0 || si->si_seq != 0)) {
143 			spp_istat.gonawy++;
144 			goto dropwithreset;
145 		}
146 		am = m_get(M_DONTWAIT, MT_SONAME);
147 		if (am == NULL)
148 			goto drop;
149 		am->m_len = sizeof (struct sockaddr_ns);
150 		sns = mtod(am, struct sockaddr_ns *);
151 		sns->sns_family = AF_NS;
152 		sns->sns_addr = si->si_sna;
153 		laddr = nsp->nsp_laddr;
154 		if (ns_nullhost(laddr))
155 			nsp->nsp_laddr = si->si_dna;
156 		if (ns_pcbconnect(nsp, am)) {
157 			nsp->nsp_laddr = laddr;
158 			(void) m_free(am);
159 			spp_istat.noconn++;
160 			goto drop;
161 		}
162 		(void) m_free(am);
163 		spp_template(cb);
164 		dropsocket = 0;		/* committed to socket */
165 		cb->s_did = si->si_sid;
166 		cb->s_rack = si->si_ack;
167 		cb->s_ralo = si->si_alo;
168 #define THREEWAYSHAKE
169 #ifdef THREEWAYSHAKE
170 		cb->s_state = TCPS_SYN_RECEIVED;
171 		cb->s_force = 1 + TCPT_KEEP;
172 		sppstat.spps_accepts++;
173 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
174 		}
175 		break;
176 	/*
177 	 * This state means that we have heard a response
178 	 * to our acceptance of their connection
179 	 * It is probably logically unnecessary in this
180 	 * implementation.
181 	 */
182 	 case TCPS_SYN_RECEIVED: {
183 		if (si->si_did!=cb->s_sid) {
184 			spp_istat.wrncon++;
185 			goto drop;
186 		}
187 #endif
188 		nsp->nsp_fport =  si->si_sport;
189 		cb->s_timer[TCPT_REXMT] = 0;
190 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
191 		soisconnected(so);
192 		cb->s_state = TCPS_ESTABLISHED;
193 		sppstat.spps_accepts++;
194 		}
195 		break;
196 
197 	/*
198 	 * This state means that we have gotten a response
199 	 * to our attempt to establish a connection.
200 	 * We fill in the data from the other side,
201 	 * telling us which port to respond to, instead of the well-
202 	 * known one we might have sent to in the first place.
203 	 * We also require that this is a response to our
204 	 * connection id.
205 	 */
206 	case TCPS_SYN_SENT:
207 		if (si->si_did!=cb->s_sid) {
208 			spp_istat.notme++;
209 			goto drop;
210 		}
211 		sppstat.spps_connects++;
212 		cb->s_did = si->si_sid;
213 		cb->s_rack = si->si_ack;
214 		cb->s_ralo = si->si_alo;
215 		cb->s_dport = nsp->nsp_fport =  si->si_sport;
216 		cb->s_timer[TCPT_REXMT] = 0;
217 		cb->s_flags |= SF_ACKNOW;
218 		soisconnected(so);
219 		cb->s_state = TCPS_ESTABLISHED;
220 		/* Use roundtrip time of connection request for initial rtt */
221 		if (cb->s_rtt) {
222 			cb->s_srtt = cb->s_rtt << 3;
223 			cb->s_rttvar = cb->s_rtt << 1;
224 			TCPT_RANGESET(cb->s_rxtcur,
225 			    ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1,
226 			    TCPTV_MIN, TCPTV_REXMTMAX);
227 			    cb->s_rtt = 0;
228 		}
229 	}
230 	if (so->so_options & SO_DEBUG || traceallspps)
231 		spp_trace(SA_INPUT, (u_char)ostate, cb, &spp_savesi, 0);
232 
233 	m->m_len -= sizeof (struct idp);
234 	m->m_off += sizeof (struct idp);
235 
236 	if (spp_reass(cb, si)) {
237 		(void) m_freem(m);
238 	}
239 	if (cb->s_force || (cb->s_flags & (SF_ACKNOW|SF_WIN|SF_RXT)))
240 		(void) spp_output(cb, (struct mbuf *)0);
241 	cb->s_flags &= ~(SF_WIN|SF_RXT);
242 	return;
243 
244 dropwithreset:
245 	if (dropsocket)
246 		(void) soabort(so);
247 	si->si_seq = ntohs(si->si_seq);
248 	si->si_ack = ntohs(si->si_ack);
249 	si->si_alo = ntohs(si->si_alo);
250 	ns_error(dtom(si), NS_ERR_NOSOCK, 0);
251 	if (cb->s_nspcb->nsp_socket->so_options & SO_DEBUG || traceallspps)
252 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
253 	return;
254 
255 drop:
256 bad:
257 	if (cb == 0 || cb->s_nspcb->nsp_socket->so_options & SO_DEBUG ||
258             traceallspps)
259 		spp_trace(SA_DROP, (u_char)ostate, cb, &spp_savesi, 0);
260 	m_freem(m);
261 }
262 
263 int spprexmtthresh = 3;
264 
265 /*
266  * This is structurally similar to the tcp reassembly routine
267  * but its function is somewhat different:  It merely queues
268  * packets up, and suppresses duplicates.
269  */
270 spp_reass(cb, si)
271 register struct sppcb *cb;
272 register struct spidp *si;
273 {
274 	register struct spidp_q *q;
275 	register struct mbuf *m;
276 	register struct socket *so = cb->s_nspcb->nsp_socket;
277 	char packetp = cb->s_flags & SF_HI;
278 	int incr;
279 	char wakeup = 0;
280 
281 	if (si == SI(0))
282 		goto present;
283 	/*
284 	 * Update our news from them.
285 	 */
286 	if (si->si_cc & SP_SA)
287 		cb->s_flags |= (spp_use_delack ? SF_DELACK : SF_ACKNOW);
288 	if (SSEQ_GT(si->si_alo, cb->s_ralo))
289 		cb->s_flags |= SF_WIN;
290 	if (SSEQ_LEQ(si->si_ack, cb->s_rack)) {
291 		if ((si->si_cc & SP_SP) && cb->s_rack != (cb->s_smax + 1)) {
292 			sppstat.spps_rcvdupack++;
293 			/*
294 			 * If this is a completely duplicate ack
295 			 * and other conditions hold, we assume
296 			 * a packet has been dropped and retransmit
297 			 * it exactly as in tcp_input().
298 			 */
299 			if (si->si_ack != cb->s_rack ||
300 			    si->si_alo != cb->s_ralo)
301 				cb->s_dupacks = 0;
302 			else if (++cb->s_dupacks == spprexmtthresh) {
303 				u_short onxt = cb->s_snxt;
304 				int cwnd = cb->s_cwnd;
305 
306 				cb->s_snxt = si->si_ack;
307 				cb->s_cwnd = CUNIT;
308 				cb->s_force = 1 + TCPT_REXMT;
309 				(void) spp_output(cb, (struct mbuf *)0);
310 				cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
311 				cb->s_rtt = 0;
312 				if (cwnd >= 4 * CUNIT)
313 					cb->s_cwnd = cwnd / 2;
314 				if (SSEQ_GT(onxt, cb->s_snxt))
315 					cb->s_snxt = onxt;
316 				return (1);
317 			}
318 		} else
319 			cb->s_dupacks = 0;
320 		goto update_window;
321 	}
322 	cb->s_dupacks = 0;
323 	/*
324 	 * If our correspondent acknowledges data we haven't sent
325 	 * TCP would drop the packet after acking.  We'll be a little
326 	 * more permissive
327 	 */
328 	if (SSEQ_GT(si->si_ack, (cb->s_smax + 1))) {
329 		sppstat.spps_rcvacktoomuch++;
330 		si->si_ack = cb->s_smax + 1;
331 	}
332 	sppstat.spps_rcvackpack++;
333 	/*
334 	 * If transmit timer is running and timed sequence
335 	 * number was acked, update smoothed round trip time.
336 	 * See discussion of algorithm in tcp_input.c
337 	 */
338 	if (cb->s_rtt && SSEQ_GT(si->si_ack, cb->s_rtseq)) {
339 		sppstat.spps_rttupdated++;
340 		if (cb->s_srtt != 0) {
341 			register short delta;
342 			delta = cb->s_rtt - (cb->s_srtt >> 3);
343 			if ((cb->s_srtt += delta) <= 0)
344 				cb->s_srtt = 1;
345 			if (delta < 0)
346 				delta = -delta;
347 			delta -= (cb->s_rttvar >> 2);
348 			if ((cb->s_rttvar += delta) <= 0)
349 				cb->s_rttvar = 1;
350 		} else {
351 			/*
352 			 * No rtt measurement yet
353 			 */
354 			cb->s_srtt = cb->s_rtt << 3;
355 			cb->s_rttvar = cb->s_rtt << 1;
356 		}
357 		cb->s_rtt = 0;
358 		cb->s_rxtshift = 0;
359 		TCPT_RANGESET(cb->s_rxtcur,
360 			((cb->s_srtt >> 2) + cb->s_rttvar) >> 1,
361 			TCPTV_MIN, TCPTV_REXMTMAX);
362 	}
363 	/*
364 	 * If all outstanding data is acked, stop retransmit
365 	 * timer and remember to restart (more output or persist).
366 	 * If there is more data to be acked, restart retransmit
367 	 * timer, using current (possibly backed-off) value;
368 	 */
369 	if (si->si_ack == cb->s_smax + 1) {
370 		cb->s_timer[TCPT_REXMT] = 0;
371 		cb->s_flags |= SF_RXT;
372 	} else if (cb->s_timer[TCPT_PERSIST] == 0)
373 		cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
374 	/*
375 	 * When new data is acked, open the congestion window.
376 	 * If the window gives us less than ssthresh packets
377 	 * in flight, open exponentially (maxseg at a time).
378 	 * Otherwise open linearly (maxseg^2 / cwnd at a time).
379 	 */
380 	incr = CUNIT;
381 	if (cb->s_cwnd > cb->s_ssthresh)
382 		incr = MAX(incr * incr / cb->s_cwnd, 1);
383 	cb->s_cwnd = MIN(cb->s_cwnd + incr, cb->s_cwmx);
384 	/*
385 	 * Trim Acked data from output queue.
386 	 */
387 	while ((m = so->so_snd.sb_mb) != NULL) {
388 		if (SSEQ_LT((mtod(m, struct spidp *))->si_seq, si->si_ack))
389 			sbdroprecord(&so->so_snd);
390 		else
391 			break;
392 	}
393 	if ((so->so_snd.sb_flags & SB_WAIT) || so->so_snd.sb_sel)
394 		 sowwakeup(so);
395 	cb->s_rack = si->si_ack;
396 update_window:
397 	if (SSEQ_LT(cb->s_snxt, cb->s_rack))
398 		cb->s_snxt = cb->s_rack;
399 	if (SSEQ_LT(cb->s_swl1, si->si_seq) || cb->s_swl1 == si->si_seq &&
400 	    (SSEQ_LT(cb->s_swl2, si->si_ack) ||
401 	     cb->s_swl2 == si->si_ack && SSEQ_LT(cb->s_ralo, si->si_alo))) {
402 		/* keep track of pure window updates */
403 		if ((si->si_cc & SP_SP) && cb->s_swl2 == si->si_ack
404 		    && SSEQ_LT(cb->s_ralo, si->si_alo)) {
405 			sppstat.spps_rcvwinupd++;
406 			sppstat.spps_rcvdupack--;
407 		}
408 		cb->s_ralo = si->si_alo;
409 		cb->s_swl1 = si->si_seq;
410 		cb->s_swl2 = si->si_ack;
411 		cb->s_swnd = (1 + si->si_alo - si->si_ack);
412 		if (cb->s_swnd > cb->s_smxw)
413 			cb->s_smxw = cb->s_swnd;
414 		cb->s_flags |= SF_WIN;
415 	}
416 	/*
417 	 * If this packet number is higher than that which
418 	 * we have allocated refuse it, unless urgent
419 	 */
420 	if (SSEQ_GT(si->si_seq, cb->s_alo)) {
421 		if (si->si_cc & SP_SP) {
422 			sppstat.spps_rcvwinprobe++;
423 			return (1);
424 		} else
425 			sppstat.spps_rcvpackafterwin++;
426 		if (si->si_cc & SP_OB) {
427 			if (SSEQ_GT(si->si_seq, cb->s_alo + 60)) {
428 				ns_error(dtom(si), NS_ERR_FULLUP, 0);
429 				return (0);
430 			} /* else queue this packet; */
431 		} else {
432 			/*register struct socket *so = cb->s_nspcb->nsp_socket;
433 			if (so->so_state && SS_NOFDREF) {
434 				ns_error(dtom(si), NS_ERR_NOSOCK, 0);
435 				(void)spp_close(cb);
436 			} else
437 				       would crash system*/
438 			spp_istat.notyet++;
439 			ns_error(dtom(si), NS_ERR_FULLUP, 0);
440 			return (0);
441 		}
442 	}
443 	/*
444 	 * If this is a system packet, we don't need to
445 	 * queue it up, and won't update acknowledge #
446 	 */
447 	if (si->si_cc & SP_SP) {
448 		return (1);
449 	}
450 	/*
451 	 * We have already seen this packet, so drop.
452 	 */
453 	if (SSEQ_LT(si->si_seq, cb->s_ack)) {
454 		spp_istat.bdreas++;
455 		sppstat.spps_rcvduppack++;
456 		if (si->si_seq == cb->s_ack - 1)
457 			spp_istat.lstdup++;
458 		return (1);
459 	}
460 	/*
461 	 * Loop through all packets queued up to insert in
462 	 * appropriate sequence.
463 	 */
464 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
465 		if (si->si_seq == SI(q)->si_seq) {
466 			sppstat.spps_rcvduppack++;
467 			return (1);
468 		}
469 		if (SSEQ_LT(si->si_seq, SI(q)->si_seq)) {
470 			sppstat.spps_rcvoopack++;
471 			break;
472 		}
473 	}
474 	insque(si, q->si_prev);
475 	/*
476 	 * If this packet is urgent, inform process
477 	 */
478 	if (si->si_cc & SP_OB) {
479 		cb->s_iobc = ((char *)si)[1 + sizeof(*si)];
480 		sohasoutofband(so);
481 		cb->s_oobflags |= SF_IOOB;
482 	}
483 present:
484 #define SPINC sizeof(struct sphdr)
485 	/*
486 	 * Loop through all packets queued up to update acknowledge
487 	 * number, and present all acknowledged data to user;
488 	 * If in packet interface mode, show packet headers.
489 	 */
490 	for (q = cb->s_q.si_next; q!=&cb->s_q; q = q->si_next) {
491 		  if (SI(q)->si_seq == cb->s_ack) {
492 			cb->s_ack++;
493 			m = dtom(q);
494 			if (SI(q)->si_cc & SP_OB) {
495 				cb->s_oobflags &= ~SF_IOOB;
496 				if (so->so_rcv.sb_cc)
497 					so->so_oobmark = so->so_rcv.sb_cc;
498 				else
499 					so->so_state |= SS_RCVATMARK;
500 			}
501 			q = q->si_prev;
502 			remque(q->si_next);
503 			wakeup = 1;
504 			sppstat.spps_rcvpack++;
505 			if (packetp) {
506 				sbappendrecord(&so->so_rcv, m);
507 			} else {
508 				cb->s_rhdr = *mtod(m, struct sphdr *);
509 				m->m_off += SPINC;
510 				m->m_len -= SPINC;
511 				sbappend(&so->so_rcv, m);
512 			}
513 		  } else
514 			break;
515 	}
516 	if (wakeup) sorwakeup(so);
517 	return (0);
518 }
519 
520 spp_ctlinput(cmd, arg)
521 	int cmd;
522 	caddr_t arg;
523 {
524 	struct ns_addr *na;
525 	extern u_char nsctlerrmap[];
526 	extern spp_abort(), spp_quench();
527 	extern struct nspcb *idp_drop();
528 	struct ns_errp *errp;
529 	struct nspcb *nsp;
530 	struct sockaddr_ns *sns;
531 	int type;
532 
533 	if (cmd < 0 || cmd > PRC_NCMDS)
534 		return;
535 	type = NS_ERR_UNREACH_HOST;
536 
537 	switch (cmd) {
538 
539 	case PRC_ROUTEDEAD:
540 		return;
541 
542 	case PRC_IFDOWN:
543 	case PRC_HOSTDEAD:
544 	case PRC_HOSTUNREACH:
545 		sns = (struct sockaddr_ns *)arg;
546 		if (sns->sns_family != AF_NS)
547 			return;
548 		na = &sns->sns_addr;
549 		break;
550 
551 	default:
552 		errp = (struct ns_errp *)arg;
553 		na = &errp->ns_err_idp.idp_dna;
554 		type = errp->ns_err_num;
555 		type = ntohs((u_short)type);
556 	}
557 	switch (type) {
558 
559 	case NS_ERR_UNREACH_HOST:
560 		ns_pcbnotify(na, (int)nsctlerrmap[cmd], spp_abort, (long) 0);
561 		break;
562 
563 	case NS_ERR_TOO_BIG:
564 	case NS_ERR_NOSOCK:
565 		nsp = ns_pcblookup(na, errp->ns_err_idp.idp_sna.x_port,
566 			NS_WILDCARD);
567 		if (nsp) {
568 			if(nsp->nsp_pcb)
569 				(void) spp_drop((struct sppcb *)nsp->nsp_pcb,
570 						(int)nsctlerrmap[cmd]);
571 			else
572 				(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
573 		}
574 		break;
575 
576 	case NS_ERR_FULLUP:
577 		ns_pcbnotify(na, 0, spp_quench, (long) 0);
578 	}
579 }
580 /*
581  * When a source quench is received, close congestion window
582  * to one packet.  We will gradually open it again as we proceed.
583  */
584 spp_quench(nsp)
585 	struct nspcb *nsp;
586 {
587 	struct sppcb *cb = nstosppcb(nsp);
588 
589 	if (cb)
590 		cb->s_cwnd = CUNIT;
591 }
592 
593 #ifdef notdef
594 int
595 spp_fixmtu(nsp)
596 register struct nspcb *nsp;
597 {
598 	register struct sppcb *cb = (struct sppcb *)(nsp->nsp_pcb);
599 	register struct mbuf *m;
600 	register struct spidp *si;
601 	struct ns_errp *ep;
602 	struct sockbuf *sb;
603 	int badseq, len;
604 	struct mbuf *firstbad, *m0;
605 
606 	if (cb) {
607 		/*
608 		 * The notification that we have sent
609 		 * too much is bad news -- we will
610 		 * have to go through queued up so far
611 		 * splitting ones which are too big and
612 		 * reassigning sequence numbers and checksums.
613 		 * we should then retransmit all packets from
614 		 * one above the offending packet to the last one
615 		 * we had sent (or our allocation)
616 		 * then the offending one so that the any queued
617 		 * data at our destination will be discarded.
618 		 */
619 		 ep = (struct ns_errp *)nsp->nsp_notify_param;
620 		 sb = &nsp->nsp_socket->so_snd;
621 		 cb->s_mtu = ep->ns_err_param;
622 		 badseq = SI(&ep->ns_err_idp)->si_seq;
623 		 for (m = sb->sb_mb; m; m = m->m_act) {
624 			si = mtod(m, struct spidp *);
625 			if (si->si_seq == badseq)
626 				break;
627 		 }
628 		 if (m == 0) return;
629 		 firstbad = m;
630 		 /*for (;;) {*/
631 			/* calculate length */
632 			for (m0 = m, len = 0; m ; m = m->m_next)
633 				len += m->m_len;
634 			if (len > cb->s_mtu) {
635 			}
636 		/* FINISH THIS
637 		} */
638 	}
639 }
640 #endif
641 
642 spp_output(cb, m0)
643 	register struct sppcb *cb;
644 	struct mbuf *m0;
645 {
646 	struct socket *so = cb->s_nspcb->nsp_socket;
647 	register struct mbuf *m;
648 	register struct spidp *si = (struct spidp *) 0;
649 	register struct sockbuf *sb = &so->so_snd;
650 	int len = 0, win, rcv_win;
651 	short span, off;
652 	u_short alo;
653 	int error = 0, idle, sendalot;
654 	struct mbuf *mprev;
655 	extern int idpcksum;
656 
657 	if (m0) {
658 		int mtu = cb->s_mtu;
659 		int datalen;
660 		/*
661 		 * Make sure that packet isn't too big.
662 		 */
663 		for (m = m0; m ; m = m->m_next) {
664 			mprev = m;
665 			len += m->m_len;
666 		}
667 		datalen = (cb->s_flags & SF_HO) ?
668 				len - sizeof (struct sphdr) : len;
669 		if (datalen > mtu) {
670 			if (cb->s_flags & SF_PI) {
671 				m_freem(m0);
672 				return (EMSGSIZE);
673 			} else {
674 				int oldEM = cb->s_cc & SP_EM;
675 
676 				cb->s_cc &= ~SP_EM;
677 				while (len > mtu) {
678 					m = m_copy(m0, 0, mtu);
679 					if (m == NULL) {
680 						error = ENOBUFS;
681 						goto bad_copy;
682 					}
683 					error = spp_output(cb, m);
684 					if (error) {
685 					bad_copy:
686 						cb->s_cc |= oldEM;
687 						m_freem(m0);
688 						return(error);
689 					}
690 					m_adj(m0, mtu);
691 					len -= mtu;
692 				}
693 				cb->s_cc |= oldEM;
694 			}
695 		}
696 		/*
697 		 * Force length even, by adding a "garbage byte" if
698 		 * necessary.
699 		 */
700 		if (len & 1) {
701 			m = mprev;
702 			if (m->m_len + m->m_off < MMAXOFF)
703 				m->m_len++;
704 			else {
705 				struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA);
706 
707 				if (m1 == 0) {
708 					m_freem(m0);
709 					return (ENOBUFS);
710 				}
711 				m1->m_len = 1;
712 				m1->m_off = MMAXOFF - 1;
713 				m->m_next = m1;
714 			}
715 		}
716 		m = m_get(M_DONTWAIT, MT_HEADER);
717 		if (m == 0) {
718 			m_freem(m0);
719 			return (ENOBUFS);
720 		}
721 		/*
722 		 * Fill in mbuf with extended SP header
723 		 * and addresses and length put into network format.
724 		 * Long align so prepended ip headers will work on Gould.
725 		 */
726 		m->m_off = MMAXOFF - sizeof (struct spidp) - 2;
727 		m->m_len = sizeof (struct spidp);
728 		m->m_next = m0;
729 		si = mtod(m, struct spidp *);
730 		si->si_i = *cb->s_idp;
731 		si->si_s = cb->s_shdr;
732 		if ((cb->s_flags & SF_PI) && (cb->s_flags & SF_HO)) {
733 			register struct sphdr *sh;
734 			if (m0->m_len < sizeof (*sh)) {
735 				if((m0 = m_pullup(m0, sizeof(*sh))) == NULL) {
736 					(void) m_free(m);
737 					m_freem(m0);
738 					return (EINVAL);
739 				}
740 				m->m_next = m0;
741 			}
742 			sh = mtod(m0, struct sphdr *);
743 			si->si_dt = sh->sp_dt;
744 			si->si_cc |= sh->sp_cc & SP_EM;
745 			m0->m_len -= sizeof (*sh);
746 			m0->m_off += sizeof (*sh);
747 			len -= sizeof (*sh);
748 		}
749 		len += sizeof(*si);
750 		if (cb->s_oobflags & SF_SOOB) {
751 			/*
752 			 * Per jqj@cornell:
753 			 * make sure OB packets convey exactly 1 byte.
754 			 * If the packet is 1 byte or larger, we
755 			 * have already guaranted there to be at least
756 			 * one garbage byte for the checksum, and
757 			 * extra bytes shouldn't hurt!
758 			 */
759 			if (len > sizeof(*si)) {
760 				si->si_cc |= SP_OB;
761 				len = (1 + sizeof(*si));
762 			}
763 		}
764 		si->si_len = htons((u_short)len);
765 		/*
766 		 * queue stuff up for output
767 		 */
768 		sbappendrecord(sb, m);
769 		cb->s_seq++;
770 	}
771 	idle = (cb->s_smax == (cb->s_rack - 1));
772 again:
773 	sendalot = 0;
774 	off = cb->s_snxt - cb->s_rack;
775 	win = MIN(cb->s_swnd, (cb->s_cwnd/CUNIT));
776 
777 	/*
778 	 * If in persist timeout with window of 0, send a probe.
779 	 * Otherwise, if window is small but nonzero
780 	 * and timer expired, send what we can and go into
781 	 * transmit state.
782 	 */
783 	if (cb->s_force == 1 + TCPT_PERSIST) {
784 		if (win != 0) {
785 			cb->s_timer[TCPT_PERSIST] = 0;
786 			cb->s_rxtshift = 0;
787 		}
788 	}
789 	span = cb->s_seq - cb->s_rack;
790 	len = MIN(span, win) - off;
791 
792 	if (len < 0) {
793 		/*
794 		 * Window shrank after we went into it.
795 		 * If window shrank to 0, cancel pending
796 		 * restransmission and pull s_snxt back
797 		 * to (closed) window.  We will enter persist
798 		 * state below.  If the widndow didn't close completely,
799 		 * just wait for an ACK.
800 		 */
801 		len = 0;
802 		if (win == 0) {
803 			cb->s_timer[TCPT_REXMT] = 0;
804 			cb->s_snxt = cb->s_rack;
805 		}
806 	}
807 	if (len > 1)
808 		sendalot = 1;
809 	rcv_win = sbspace(&so->so_rcv);
810 
811 	/*
812 	 * Send if we owe peer an ACK.
813 	 */
814 	if (cb->s_oobflags & SF_SOOB) {
815 		/*
816 		 * must transmit this out of band packet
817 		 */
818 		cb->s_oobflags &= ~ SF_SOOB;
819 		sendalot = 1;
820 		sppstat.spps_sndurg++;
821 		goto found;
822 	}
823 	if (cb->s_flags & SF_ACKNOW)
824 		goto send;
825 	if (cb->s_state < TCPS_ESTABLISHED)
826 		goto send;
827 	/*
828 	 * Silly window can't happen in spp.
829 	 * Code from tcp deleted.
830 	 */
831 	if (len)
832 		goto send;
833 	/*
834 	 * Compare available window to amount of window
835 	 * known to peer (as advertised window less
836 	 * next expected input.)  If the difference is at least two
837 	 * packets or at least 35% of the mximum possible window,
838 	 * then want to send a window update to peer.
839 	 */
840 	if (rcv_win > 0) {
841 		u_short delta =  1 + cb->s_alo - cb->s_ack;
842 		int adv = rcv_win - (delta * cb->s_mtu);
843 
844 		if ((so->so_rcv.sb_cc == 0 && adv >= (2 * cb->s_mtu)) ||
845 		    (100 * adv / so->so_rcv.sb_hiwat >= 35)) {
846 			sppstat.spps_sndwinup++;
847 			cb->s_flags |= SF_ACKNOW;
848 			goto send;
849 		}
850 
851 	}
852 	/*
853 	 * Many comments from tcp_output.c are appropriate here
854 	 * including . . .
855 	 * If send window is too small, there is data to transmit, and no
856 	 * retransmit or persist is pending, then go to persist state.
857 	 * If nothing happens soon, send when timer expires:
858 	 * if window is nonzero, transmit what we can,
859 	 * otherwise send a probe.
860 	 */
861 	if (so->so_snd.sb_cc && cb->s_timer[TCPT_REXMT] == 0 &&
862 		cb->s_timer[TCPT_PERSIST] == 0) {
863 			cb->s_rxtshift = 0;
864 			spp_setpersist(cb);
865 	}
866 	/*
867 	 * No reason to send a packet, just return.
868 	 */
869 	cb->s_outx = 1;
870 	return (0);
871 
872 send:
873 	/*
874 	 * Find requested packet.
875 	 */
876 	si = 0;
877 	if (len > 0) {
878 		cb->s_want = cb->s_snxt;
879 		for (m = sb->sb_mb; m; m = m->m_act) {
880 			si = mtod(m, struct spidp *);
881 			if (SSEQ_LEQ(cb->s_snxt, si->si_seq))
882 				break;
883 		}
884 	found:
885 		if (si) {
886 			if (si->si_seq == cb->s_snxt)
887 					cb->s_snxt++;
888 				else
889 					sppstat.spps_sndvoid++, si = 0;
890 		}
891 	}
892 	/*
893 	 * update window
894 	 */
895 	if (rcv_win < 0)
896 		rcv_win = 0;
897 	alo = cb->s_ack - 1 + (rcv_win / ((short)cb->s_mtu));
898 	if (SSEQ_LT(alo, cb->s_alo))
899 		alo = cb->s_alo;
900 
901 	if (si) {
902 		/*
903 		 * must make a copy of this packet for
904 		 * idp_output to monkey with
905 		 */
906 		m = m_copy(dtom(si), 0, (int)M_COPYALL);
907 		if (m == NULL) {
908 			return (ENOBUFS);
909 		}
910 		m0 = m;
911 		si = mtod(m, struct spidp *);
912 		if (SSEQ_LT(si->si_seq, cb->s_smax))
913 			sppstat.spps_sndrexmitpack++;
914 		else
915 			sppstat.spps_sndpack++;
916 	} else if (cb->s_force || cb->s_flags & SF_ACKNOW) {
917 		/*
918 		 * Must send an acknowledgement or a probe
919 		 */
920 		if (cb->s_force)
921 			sppstat.spps_sndprobe++;
922 		if (cb->s_flags & SF_ACKNOW)
923 			sppstat.spps_sndacks++;
924 		m = m_get(M_DONTWAIT, MT_HEADER);
925 		if (m == 0) {
926 			return (ENOBUFS);
927 		}
928 		/*
929 		 * Fill in mbuf with extended SP header
930 		 * and addresses and length put into network format.
931 		 * Allign beginning of packet to long to prepend
932 		 * ifp's on loopback, or NSIP encaspulation for fussy cpu's.
933 		 */
934 		m->m_off = MMAXOFF - sizeof (struct spidp) - 2;
935 		m->m_len = sizeof (*si);
936 		m->m_next = 0;
937 		si = mtod(m, struct spidp *);
938 		si->si_i = *cb->s_idp;
939 		si->si_s = cb->s_shdr;
940 		si->si_seq = cb->s_smax + 1;
941 		si->si_len = htons(sizeof (*si));
942 		si->si_cc |= SP_SP;
943 	} else {
944 		cb->s_outx = 3;
945 		if (so->so_options & SO_DEBUG || traceallspps)
946 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
947 		return (0);
948 	}
949 	/*
950 	 * Stuff checksum and output datagram.
951 	 */
952 	if ((si->si_cc & SP_SP) == 0) {
953 		if (cb->s_force != (1 + TCPT_PERSIST) ||
954 		    cb->s_timer[TCPT_PERSIST] == 0) {
955 			/*
956 			 * If this is a new packet and we are not currently
957 			 * timing anything, time this one.
958 			 */
959 			if (SSEQ_LT(cb->s_smax, si->si_seq)) {
960 				cb->s_smax = si->si_seq;
961 				if (cb->s_rtt == 0) {
962 					sppstat.spps_segstimed++;
963 					cb->s_rtseq = si->si_seq;
964 					cb->s_rtt = 1;
965 				}
966 			}
967 			/*
968 			 * Set rexmt timer if not currently set,
969 			 * Initial value for retransmit timer is smoothed
970 			 * round-trip time + 2 * round-trip time variance.
971 			 * Initialize shift counter which is used for backoff
972 			 * of retransmit time.
973 			 */
974 			if (cb->s_timer[TCPT_REXMT] == 0 &&
975 			    cb->s_snxt != cb->s_rack) {
976 				cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
977 				if (cb->s_timer[TCPT_PERSIST]) {
978 					cb->s_timer[TCPT_PERSIST] = 0;
979 					cb->s_rxtshift = 0;
980 				}
981 			}
982 		} else if (SSEQ_LT(cb->s_smax, si->si_seq)) {
983 			cb->s_smax = si->si_seq;
984 		}
985 	} else if (cb->s_state < TCPS_ESTABLISHED) {
986 		if (cb->s_rtt == 0)
987 			cb->s_rtt = 1; /* Time initial handshake */
988 		if (cb->s_timer[TCPT_REXMT] == 0)
989 			cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
990 	}
991 	{
992 		/*
993 		 * Do not request acks when we ack their data packets or
994 		 * when we do a gratuitous window update.
995 		 */
996 		if (((si->si_cc & SP_SP) == 0) || cb->s_force)
997 				si->si_cc |= SP_SA;
998 		si->si_seq = htons(si->si_seq);
999 		si->si_alo = htons(alo);
1000 		si->si_ack = htons(cb->s_ack);
1001 
1002 		if (idpcksum) {
1003 			si->si_sum = 0;
1004 			len = ntohs(si->si_len);
1005 			if (len & 1)
1006 				len++;
1007 			si->si_sum = ns_cksum(dtom(si), len);
1008 		} else
1009 			si->si_sum = 0xffff;
1010 
1011 		cb->s_outx = 4;
1012 		if (so->so_options & SO_DEBUG || traceallspps)
1013 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
1014 
1015 		if (so->so_options & SO_DONTROUTE)
1016 			error = ns_output(m, (struct route *)0, NS_ROUTETOIF);
1017 		else
1018 			error = ns_output(m, &cb->s_nspcb->nsp_route, 0);
1019 	}
1020 	if (error) {
1021 		return (error);
1022 	}
1023 	sppstat.spps_sndtotal++;
1024 	/*
1025 	 * Data sent (as far as we can tell).
1026 	 * If this advertises a larger window than any other segment,
1027 	 * then remember the size of the advertized window.
1028 	 * Any pending ACK has now been sent.
1029 	 */
1030 	cb->s_force = 0;
1031 	cb->s_flags &= ~(SF_ACKNOW|SF_DELACK);
1032 	if (SSEQ_GT(alo, cb->s_alo))
1033 		cb->s_alo = alo;
1034 	if (sendalot)
1035 		goto again;
1036 	cb->s_outx = 5;
1037 	return (0);
1038 }
1039 
1040 int spp_do_persist_panics = 0;
1041 
1042 spp_setpersist(cb)
1043 	register struct sppcb *cb;
1044 {
1045 	register t = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1046 	extern int spp_backoff[];
1047 
1048 	if (cb->s_timer[TCPT_REXMT] && spp_do_persist_panics)
1049 		panic("spp_output REXMT");
1050 	/*
1051 	 * Start/restart persistance timer.
1052 	 */
1053 	TCPT_RANGESET(cb->s_timer[TCPT_PERSIST],
1054 	    t*spp_backoff[cb->s_rxtshift],
1055 	    TCPTV_PERSMIN, TCPTV_PERSMAX);
1056 	if (cb->s_rxtshift < TCP_MAXRXTSHIFT)
1057 		cb->s_rxtshift++;
1058 }
1059 /*ARGSUSED*/
1060 spp_ctloutput(req, so, level, name, value)
1061 	int req;
1062 	struct socket *so;
1063 	int name;
1064 	struct mbuf **value;
1065 {
1066 	register struct mbuf *m;
1067 	struct nspcb *nsp = sotonspcb(so);
1068 	register struct sppcb *cb;
1069 	int mask, error = 0;
1070 
1071 	if (level != NSPROTO_SPP) {
1072 		/* This will have to be changed when we do more general
1073 		   stacking of protocols */
1074 		return (idp_ctloutput(req, so, level, name, value));
1075 	}
1076 	if (nsp == NULL) {
1077 		error = EINVAL;
1078 		goto release;
1079 	} else
1080 		cb = nstosppcb(nsp);
1081 
1082 	switch (req) {
1083 
1084 	case PRCO_GETOPT:
1085 		if (value == NULL)
1086 			return (EINVAL);
1087 		m = m_get(M_DONTWAIT, MT_DATA);
1088 		if (m == NULL)
1089 			return (ENOBUFS);
1090 		switch (name) {
1091 
1092 		case SO_HEADERS_ON_INPUT:
1093 			mask = SF_HI;
1094 			goto get_flags;
1095 
1096 		case SO_HEADERS_ON_OUTPUT:
1097 			mask = SF_HO;
1098 		get_flags:
1099 			m->m_len = sizeof(short);
1100 			m->m_off = MMAXOFF - sizeof(short);
1101 			*mtod(m, short *) = cb->s_flags & mask;
1102 			break;
1103 
1104 		case SO_MTU:
1105 			m->m_len = sizeof(u_short);
1106 			m->m_off = MMAXOFF - sizeof(short);
1107 			*mtod(m, short *) = cb->s_mtu;
1108 			break;
1109 
1110 		case SO_LAST_HEADER:
1111 			m->m_len = sizeof(struct sphdr);
1112 			m->m_off = MMAXOFF - sizeof(struct sphdr);
1113 			*mtod(m, struct sphdr *) = cb->s_rhdr;
1114 			break;
1115 
1116 		case SO_DEFAULT_HEADERS:
1117 			m->m_len = sizeof(struct spidp);
1118 			m->m_off = MMAXOFF - sizeof(struct sphdr);
1119 			*mtod(m, struct sphdr *) = cb->s_shdr;
1120 			break;
1121 
1122 		default:
1123 			error = EINVAL;
1124 		}
1125 		*value = m;
1126 		break;
1127 
1128 	case PRCO_SETOPT:
1129 		if (value == 0 || *value == 0) {
1130 			error = EINVAL;
1131 			break;
1132 		}
1133 		switch (name) {
1134 			int *ok;
1135 
1136 		case SO_HEADERS_ON_INPUT:
1137 			mask = SF_HI;
1138 			goto set_head;
1139 
1140 		case SO_HEADERS_ON_OUTPUT:
1141 			mask = SF_HO;
1142 		set_head:
1143 			if (cb->s_flags & SF_PI) {
1144 				ok = mtod(*value, int *);
1145 				if (*ok)
1146 					cb->s_flags |= mask;
1147 				else
1148 					cb->s_flags &= ~mask;
1149 			} else error = EINVAL;
1150 			break;
1151 
1152 		case SO_MTU:
1153 			cb->s_mtu = *(mtod(*value, u_short *));
1154 			break;
1155 
1156 		case SO_DEFAULT_HEADERS:
1157 			{
1158 				register struct sphdr *sp
1159 						= mtod(*value, struct sphdr *);
1160 				cb->s_dt = sp->sp_dt;
1161 				cb->s_cc = sp->sp_cc & SP_EM;
1162 			}
1163 			break;
1164 
1165 		default:
1166 			error = EINVAL;
1167 		}
1168 		m_freem(*value);
1169 		break;
1170 	}
1171 	release:
1172 		return (error);
1173 }
1174 
1175 /*ARGSUSED*/
1176 spp_usrreq(so, req, m, nam, rights)
1177 	struct socket *so;
1178 	int req;
1179 	struct mbuf *m, *nam, *rights;
1180 {
1181 	struct nspcb *nsp = sotonspcb(so);
1182 	register struct sppcb *cb;
1183 	int s = splnet();
1184 	int error = 0, ostate;
1185 	struct mbuf *mm;
1186 	register struct sockbuf *sb;
1187 
1188 	if (req == PRU_CONTROL)
1189                 return (ns_control(so, (int)m, (caddr_t)nam,
1190 			(struct ifnet *)rights));
1191 	if (rights && rights->m_len) {
1192 		error = EINVAL;
1193 		goto release;
1194 	}
1195 	if (nsp == NULL) {
1196 		if (req != PRU_ATTACH) {
1197 			error = EINVAL;
1198 			goto release;
1199 		}
1200 	} else
1201 		cb = nstosppcb(nsp);
1202 
1203 	ostate = cb ? cb->s_state : 0;
1204 
1205 	switch (req) {
1206 
1207 	case PRU_ATTACH:
1208 		if (nsp != NULL) {
1209 			error = EISCONN;
1210 			break;
1211 		}
1212 		error = ns_pcballoc(so, &nspcb);
1213 		if (error)
1214 			break;
1215 		error = soreserve(so, 3072, 3072);
1216 		if (error)
1217 			break;
1218 		nsp = sotonspcb(so);
1219 
1220 		mm = m_getclr(M_DONTWAIT, MT_PCB);
1221 		sb = &so->so_snd;
1222 
1223 		if (mm == NULL) {
1224 			error = ENOBUFS;
1225 			break;
1226 		}
1227 		cb = mtod(mm, struct sppcb *);
1228 		mm = m_getclr(M_DONTWAIT, MT_HEADER);
1229 		if (mm == NULL) {
1230 			m_free(dtom(m));
1231 			error = ENOBUFS;
1232 			break;
1233 		}
1234 		cb->s_idp = mtod(mm, struct idp *);
1235 		cb->s_state = TCPS_LISTEN;
1236 		cb->s_smax = -1;
1237 		cb->s_swl1 = -1;
1238 		cb->s_q.si_next = cb->s_q.si_prev = &cb->s_q;
1239 		cb->s_nspcb = nsp;
1240 		cb->s_mtu = 576 - sizeof (struct spidp);
1241 		cb->s_cwnd = sbspace(sb) * CUNIT / cb->s_mtu;
1242 		cb->s_ssthresh = cb->s_cwnd;
1243 		cb->s_cwmx = sb->sb_mbmax * CUNIT /
1244 				(2 * sizeof (struct spidp));
1245 		/* Above is recomputed when connecting to account
1246 		   for changed buffering or mtu's */
1247 		cb->s_rtt = TCPTV_SRTTBASE;
1248 		cb->s_rttvar = TCPTV_SRTTDFLT << 2;
1249 		TCPT_RANGESET(cb->s_rxtcur,
1250 		    ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
1251 		    TCPTV_MIN, TCPTV_REXMTMAX);
1252 		nsp->nsp_pcb = (caddr_t) cb;
1253 		break;
1254 
1255 	case PRU_DETACH:
1256 		if (nsp == NULL) {
1257 			error = ENOTCONN;
1258 			break;
1259 		}
1260 		if (cb->s_state > TCPS_LISTEN)
1261 			cb = spp_disconnect(cb);
1262 		else
1263 			cb = spp_close(cb);
1264 		break;
1265 
1266 	case PRU_BIND:
1267 		error = ns_pcbbind(nsp, nam);
1268 		break;
1269 
1270 	case PRU_LISTEN:
1271 		if (nsp->nsp_lport == 0)
1272 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1273 		if (error == 0)
1274 			cb->s_state = TCPS_LISTEN;
1275 		break;
1276 
1277 	/*
1278 	 * Initiate connection to peer.
1279 	 * Enter SYN_SENT state, and mark socket as connecting.
1280 	 * Start keep-alive timer, setup prototype header,
1281 	 * Send initial system packet requesting connection.
1282 	 */
1283 	case PRU_CONNECT:
1284 		if (nsp->nsp_lport == 0) {
1285 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1286 			if (error)
1287 				break;
1288 		}
1289 		error = ns_pcbconnect(nsp, nam);
1290 		if (error)
1291 			break;
1292 		soisconnecting(so);
1293 		sppstat.spps_connattempt++;
1294 		cb->s_state = TCPS_SYN_SENT;
1295 		cb->s_did = 0;
1296 		spp_template(cb);
1297 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
1298 		cb->s_force = 1 + TCPTV_KEEP;
1299 		/*
1300 		 * Other party is required to respond to
1301 		 * the port I send from, but he is not
1302 		 * required to answer from where I am sending to,
1303 		 * so allow wildcarding.
1304 		 * original port I am sending to is still saved in
1305 		 * cb->s_dport.
1306 		 */
1307 		nsp->nsp_fport = 0;
1308 		error = spp_output(cb, (struct mbuf *) 0);
1309 		break;
1310 
1311 	case PRU_CONNECT2:
1312 		error = EOPNOTSUPP;
1313 		break;
1314 
1315 	/*
1316 	 * We may decide later to implement connection closing
1317 	 * handshaking at the spp level optionally.
1318 	 * here is the hook to do it:
1319 	 */
1320 	case PRU_DISCONNECT:
1321 		cb = spp_disconnect(cb);
1322 		break;
1323 
1324 	/*
1325 	 * Accept a connection.  Essentially all the work is
1326 	 * done at higher levels; just return the address
1327 	 * of the peer, storing through addr.
1328 	 */
1329 	case PRU_ACCEPT: {
1330 		struct sockaddr_ns *sns = mtod(nam, struct sockaddr_ns *);
1331 
1332 		nam->m_len = sizeof (struct sockaddr_ns);
1333 		sns->sns_family = AF_NS;
1334 		sns->sns_addr = nsp->nsp_faddr;
1335 		break;
1336 		}
1337 
1338 	case PRU_SHUTDOWN:
1339 		socantsendmore(so);
1340 		cb = spp_usrclosed(cb);
1341 		if (cb)
1342 			error = spp_output(cb, (struct mbuf *) 0);
1343 		break;
1344 
1345 	/*
1346 	 * After a receive, possibly send acknowledgment
1347 	 * updating allocation.
1348 	 */
1349 	case PRU_RCVD:
1350 		cb->s_flags |= SF_RVD;
1351 		(void) spp_output(cb, (struct mbuf *) 0);
1352 		cb->s_flags &= ~SF_RVD;
1353 		break;
1354 
1355 	case PRU_ABORT:
1356 		(void) spp_drop(cb, ECONNABORTED);
1357 		break;
1358 
1359 	case PRU_SENSE:
1360 	case PRU_CONTROL:
1361 		m = NULL;
1362 		error = EOPNOTSUPP;
1363 		break;
1364 
1365 	case PRU_RCVOOB:
1366 		if ((cb->s_oobflags & SF_IOOB) || so->so_oobmark ||
1367 		    (so->so_state & SS_RCVATMARK)) {
1368 			m->m_len = 1;
1369 			*mtod(m, caddr_t) = cb->s_iobc;
1370 			break;
1371 		}
1372 		error = EINVAL;
1373 		break;
1374 
1375 	case PRU_SENDOOB:
1376 		if (sbspace(&so->so_snd) < -512) {
1377 			error = ENOBUFS;
1378 			break;
1379 		}
1380 		cb->s_oobflags |= SF_SOOB;
1381 		/* fall into */
1382 	case PRU_SEND:
1383 		error = spp_output(cb, m);
1384 		m = NULL;
1385 		break;
1386 
1387 	case PRU_SOCKADDR:
1388 		ns_setsockaddr(nsp, nam);
1389 		break;
1390 
1391 	case PRU_PEERADDR:
1392 		ns_setpeeraddr(nsp, nam);
1393 		break;
1394 
1395 	case PRU_SLOWTIMO:
1396 		cb = spp_timers(cb, (int)nam);
1397 		req |= ((int)nam) << 8;
1398 		break;
1399 
1400 	case PRU_FASTTIMO:
1401 	case PRU_PROTORCV:
1402 	case PRU_PROTOSEND:
1403 		error =  EOPNOTSUPP;
1404 		break;
1405 
1406 	default:
1407 		panic("sp_usrreq");
1408 	}
1409 	if (cb && (so->so_options & SO_DEBUG || traceallspps))
1410 		spp_trace(SA_USER, (u_char)ostate, cb, (struct spidp *)0, req);
1411 release:
1412 	if (m != NULL)
1413 		m_freem(m);
1414 	splx(s);
1415 	return (error);
1416 }
1417 
1418 spp_usrreq_sp(so, req, m, nam, rights)
1419 	struct socket *so;
1420 	int req;
1421 	struct mbuf *m, *nam, *rights;
1422 {
1423 	int error = spp_usrreq(so, req, m, nam, rights);
1424 
1425 	if (req == PRU_ATTACH && error == 0) {
1426 		struct nspcb *nsp = sotonspcb(so);
1427 		((struct sppcb *)nsp->nsp_pcb)->s_flags |=
1428 					(SF_HI | SF_HO | SF_PI);
1429 	}
1430 	return (error);
1431 }
1432 
1433 /*
1434  * Create template to be used to send spp packets on a connection.
1435  * Called after host entry created, fills
1436  * in a skeletal spp header (choosing connection id),
1437  * minimizing the amount of work necessary when the connection is used.
1438  */
1439 spp_template(cb)
1440 	register struct sppcb *cb;
1441 {
1442 	register struct nspcb *nsp = cb->s_nspcb;
1443 	register struct idp *idp = cb->s_idp;
1444 	register struct sockbuf *sb = &(nsp->nsp_socket->so_snd);
1445 
1446 	idp->idp_pt = NSPROTO_SPP;
1447 	idp->idp_sna = nsp->nsp_laddr;
1448 	idp->idp_dna = nsp->nsp_faddr;
1449 	cb->s_sid = htons(spp_iss);
1450 	spp_iss += SPP_ISSINCR/2;
1451 	cb->s_alo = 1;
1452 	cb->s_cwnd = (sbspace(sb) * CUNIT) / cb->s_mtu;
1453 	cb->s_ssthresh = cb->s_cwnd; /* Try to expand fast to full complement
1454 					of large packets */
1455 	cb->s_cwmx = (sb->sb_mbmax * CUNIT) / (2 * sizeof(struct spidp));
1456 	cb->s_cwmx = MAX(cb->s_cwmx, cb->s_cwnd);
1457 		/* But allow for lots of little packets as well */
1458 }
1459 
1460 /*
1461  * Close a SPIP control block:
1462  *	discard spp control block itself
1463  *	discard ns protocol control block
1464  *	wake up any sleepers
1465  */
1466 struct sppcb *
1467 spp_close(cb)
1468 	register struct sppcb *cb;
1469 {
1470 	register struct spidp_q *s;
1471 	struct nspcb *nsp = cb->s_nspcb;
1472 	struct socket *so = nsp->nsp_socket;
1473 	register struct mbuf *m;
1474 
1475 	s = cb->s_q.si_next;
1476 	while (s != &(cb->s_q)) {
1477 		s = s->si_next;
1478 		m = dtom(s->si_prev);
1479 		remque(s->si_prev);
1480 		m_freem(m);
1481 	}
1482 	(void) m_free(dtom(cb->s_idp));
1483 	(void) m_free(dtom(cb));
1484 	nsp->nsp_pcb = 0;
1485 	soisdisconnected(so);
1486 	ns_pcbdetach(nsp);
1487 	sppstat.spps_closed++;
1488 	return ((struct sppcb *)0);
1489 }
1490 /*
1491  *	Someday we may do level 3 handshaking
1492  *	to close a connection or send a xerox style error.
1493  *	For now, just close.
1494  */
1495 struct sppcb *
1496 spp_usrclosed(cb)
1497 	register struct sppcb *cb;
1498 {
1499 	return (spp_close(cb));
1500 }
1501 struct sppcb *
1502 spp_disconnect(cb)
1503 	register struct sppcb *cb;
1504 {
1505 	return (spp_close(cb));
1506 }
1507 /*
1508  * Drop connection, reporting
1509  * the specified error.
1510  */
1511 struct sppcb *
1512 spp_drop(cb, errno)
1513 	register struct sppcb *cb;
1514 	int errno;
1515 {
1516 	struct socket *so = cb->s_nspcb->nsp_socket;
1517 
1518 	/*
1519 	 * someday, in the xerox world
1520 	 * we will generate error protocol packets
1521 	 * announcing that the socket has gone away.
1522 	 */
1523 	if (TCPS_HAVERCVDSYN(cb->s_state)) {
1524 		sppstat.spps_drops++;
1525 		cb->s_state = TCPS_CLOSED;
1526 		/*(void) tcp_output(cb);*/
1527 	} else
1528 		sppstat.spps_conndrops++;
1529 	so->so_error = errno;
1530 	return (spp_close(cb));
1531 }
1532 
1533 spp_abort(nsp)
1534 	struct nspcb *nsp;
1535 {
1536 
1537 	(void) spp_close((struct sppcb *)nsp->nsp_pcb);
1538 }
1539 
1540 int	spp_backoff[TCP_MAXRXTSHIFT+1] =
1541     { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
1542 /*
1543  * Fast timeout routine for processing delayed acks
1544  */
1545 spp_fasttimo()
1546 {
1547 	register struct nspcb *nsp;
1548 	register struct sppcb *cb;
1549 	int s = splnet();
1550 
1551 	nsp = nspcb.nsp_next;
1552 	if (nsp)
1553 	for (; nsp != &nspcb; nsp = nsp->nsp_next)
1554 		if ((cb = (struct sppcb *)nsp->nsp_pcb) &&
1555 		    (cb->s_flags & SF_DELACK)) {
1556 			cb->s_flags &= ~SF_DELACK;
1557 			cb->s_flags |= SF_ACKNOW;
1558 			sppstat.spps_delack++;
1559 			(void) spp_output(cb, (struct mbuf *) 0);
1560 		}
1561 	splx(s);
1562 }
1563 
1564 /*
1565  * spp protocol timeout routine called every 500 ms.
1566  * Updates the timers in all active pcb's and
1567  * causes finite state machine actions if timers expire.
1568  */
1569 spp_slowtimo()
1570 {
1571 	register struct nspcb *ip, *ipnxt;
1572 	register struct sppcb *cb;
1573 	int s = splnet();
1574 	register int i;
1575 
1576 	/*
1577 	 * Search through tcb's and update active timers.
1578 	 */
1579 	ip = nspcb.nsp_next;
1580 	if (ip == 0) {
1581 		splx(s);
1582 		return;
1583 	}
1584 	while (ip != &nspcb) {
1585 		cb = nstosppcb(ip);
1586 		ipnxt = ip->nsp_next;
1587 		if (cb == 0)
1588 			goto tpgone;
1589 		for (i = 0; i < TCPT_NTIMERS; i++) {
1590 			if (cb->s_timer[i] && --cb->s_timer[i] == 0) {
1591 				(void) spp_usrreq(cb->s_nspcb->nsp_socket,
1592 				    PRU_SLOWTIMO, (struct mbuf *)0,
1593 				    (struct mbuf *)i, (struct mbuf *)0);
1594 				if (ipnxt->nsp_prev != ip)
1595 					goto tpgone;
1596 			}
1597 		}
1598 		cb->s_idle++;
1599 		if (cb->s_rtt)
1600 			cb->s_rtt++;
1601 tpgone:
1602 		ip = ipnxt;
1603 	}
1604 	spp_iss += SPP_ISSINCR/PR_SLOWHZ;		/* increment iss */
1605 	splx(s);
1606 }
1607 /*
1608  * SPP timer processing.
1609  */
1610 struct sppcb *
1611 spp_timers(cb, timer)
1612 	register struct sppcb *cb;
1613 	int timer;
1614 {
1615 	long rexmt;
1616 	int win;
1617 
1618 	cb->s_force = 1 + timer;
1619 	switch (timer) {
1620 
1621 	/*
1622 	 * 2 MSL timeout in shutdown went off.  TCP deletes connection
1623 	 * control block.
1624 	 */
1625 	case TCPT_2MSL:
1626 		printf("spp: TCPT_2MSL went off for no reason\n");
1627 		cb->s_timer[timer] = 0;
1628 		break;
1629 
1630 	/*
1631 	 * Retransmission timer went off.  Message has not
1632 	 * been acked within retransmit interval.  Back off
1633 	 * to a longer retransmit interval and retransmit one packet.
1634 	 */
1635 	case TCPT_REXMT:
1636 		if (++cb->s_rxtshift > TCP_MAXRXTSHIFT) {
1637 			cb->s_rxtshift = TCP_MAXRXTSHIFT;
1638 			sppstat.spps_timeoutdrop++;
1639 			cb = spp_drop(cb, ETIMEDOUT);
1640 			break;
1641 		}
1642 		sppstat.spps_rexmttimeo++;
1643 		rexmt = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1644 		rexmt *= spp_backoff[cb->s_rxtshift];
1645 		TCPT_RANGESET(cb->s_rxtcur, rexmt, TCPTV_MIN, TCPTV_REXMTMAX);
1646 		cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
1647 		/*
1648 		 * If we have backed off fairly far, our srtt
1649 		 * estimate is probably bogus.  Clobber it
1650 		 * so we'll take the next rtt measurement as our srtt;
1651 		 * move the current srtt into rttvar to keep the current
1652 		 * retransmit times until then.
1653 		 */
1654 		if (cb->s_rxtshift > TCP_MAXRXTSHIFT / 4 ) {
1655 			cb->s_rttvar += (cb->s_srtt >> 2);
1656 			cb->s_srtt = 0;
1657 		}
1658 		cb->s_snxt = cb->s_rack;
1659 		/*
1660 		 * If timing a packet, stop the timer.
1661 		 */
1662 		cb->s_rtt = 0;
1663 		/*
1664 		 * See very long discussion in tcp_timer.c about congestion
1665 		 * window and sstrhesh
1666 		 */
1667 		win = MIN(cb->s_swnd, (cb->s_cwnd/CUNIT)) / 2;
1668 		if (win < 2)
1669 			win = 2;
1670 		cb->s_cwnd = CUNIT;
1671 		cb->s_ssthresh = win * CUNIT;
1672 		(void) spp_output(cb, (struct mbuf *) 0);
1673 		break;
1674 
1675 	/*
1676 	 * Persistance timer into zero window.
1677 	 * Force a probe to be sent.
1678 	 */
1679 	case TCPT_PERSIST:
1680 		sppstat.spps_persisttimeo++;
1681 		spp_setpersist(cb);
1682 		(void) spp_output(cb, (struct mbuf *) 0);
1683 		break;
1684 
1685 	/*
1686 	 * Keep-alive timer went off; send something
1687 	 * or drop connection if idle for too long.
1688 	 */
1689 	case TCPT_KEEP:
1690 		sppstat.spps_keeptimeo++;
1691 		if (cb->s_state < TCPS_ESTABLISHED)
1692 			goto dropit;
1693 		if (cb->s_nspcb->nsp_socket->so_options & SO_KEEPALIVE) {
1694 		    	if (cb->s_idle >= TCPTV_MAXIDLE)
1695 				goto dropit;
1696 			sppstat.spps_keepprobe++;
1697 			(void) spp_output(cb, (struct mbuf *) 0);
1698 		} else
1699 			cb->s_idle = 0;
1700 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
1701 		break;
1702 	dropit:
1703 		sppstat.spps_keepdrops++;
1704 		cb = spp_drop(cb, ETIMEDOUT);
1705 		break;
1706 	}
1707 	return (cb);
1708 }
1709 #ifndef lint
1710 int SppcbSize = sizeof (struct sppcb);
1711 int NspcbSize = sizeof (struct nspcb);
1712 #endif lint
1713