xref: /csrg-svn/sys/netns/spp_usrreq.c (revision 33371)
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	7.4 (Berkeley) 01/20/88
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 		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) {
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, 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 	for (m = so->so_snd.sb_mb; m; m = m->m_act) {
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, oalo;
653 	int error = 0, idle, sendalot;
654 	u_short lookfor = 0;
655 	struct mbuf *mprev;
656 	extern int idpcksum;
657 
658 	if (m0) {
659 		int mtu = cb->s_mtu;
660 		int datalen;
661 		/*
662 		 * Make sure that packet isn't too big.
663 		 */
664 		for (m = m0; m ; m = m->m_next) {
665 			mprev = m;
666 			len += m->m_len;
667 		}
668 		datalen = (cb->s_flags & SF_HO) ?
669 				len - sizeof (struct sphdr) : len;
670 		if (datalen > mtu) {
671 			if (cb->s_flags & SF_PI) {
672 				m_freem(m0);
673 				return (EMSGSIZE);
674 			} else {
675 				int off = 0;
676 				int oldEM = cb->s_cc & SP_EM;
677 
678 				cb->s_cc &= ~SP_EM;
679 				while (len > mtu) {
680 					m = m_copy(m0, off, mtu);
681 					if (m == NULL) {
682 						error = ENOBUFS;
683 						goto bad_copy;
684 					}
685 					error = spp_output(cb, m);
686 					if (error) {
687 					bad_copy:
688 						cb->s_cc |= oldEM;
689 						m_freem(m0);
690 						return(error);
691 					}
692 					m_adj(m0, mtu);
693 					len -= mtu;
694 				}
695 				cb->s_cc |= oldEM;
696 			}
697 		}
698 		/*
699 		 * Force length even, by adding a "garbage byte" if
700 		 * necessary.
701 		 */
702 		if (len & 1) {
703 			m = mprev;
704 			if (m->m_len + m->m_off < MMAXOFF)
705 				m->m_len++;
706 			else {
707 				struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA);
708 
709 				if (m1 == 0) {
710 					m_freem(m0);
711 					return (ENOBUFS);
712 				}
713 				m1->m_len = 1;
714 				m1->m_off = MMAXOFF - 1;
715 				m->m_next = m1;
716 			}
717 		}
718 		m = m_get(M_DONTWAIT, MT_HEADER);
719 		if (m == 0) {
720 			m_freem(m0);
721 			return (ENOBUFS);
722 		}
723 		/*
724 		 * Fill in mbuf with extended SP header
725 		 * and addresses and length put into network format.
726 		 * Long align so prepended ip headers will work on Gould.
727 		 */
728 		m->m_off = MMAXOFF - sizeof (struct spidp) - 2;
729 		m->m_len = sizeof (struct spidp);
730 		m->m_next = m0;
731 		si = mtod(m, struct spidp *);
732 		si->si_i = *cb->s_idp;
733 		si->si_s = cb->s_shdr;
734 		if ((cb->s_flags & SF_PI) && (cb->s_flags & SF_HO)) {
735 			register struct sphdr *sh;
736 			if (m0->m_len < sizeof (*sh)) {
737 				if((m0 = m_pullup(m0, sizeof(*sh))) == NULL) {
738 					(void) m_free(m);
739 					m_freem(m0);
740 					return (EINVAL);
741 				}
742 				m->m_next = m0;
743 			}
744 			sh = mtod(m0, struct sphdr *);
745 			si->si_dt = sh->sp_dt;
746 			si->si_cc |= sh->sp_cc & SP_EM;
747 			m0->m_len -= sizeof (*sh);
748 			m0->m_off += sizeof (*sh);
749 			len -= sizeof (*sh);
750 		}
751 		len += sizeof(*si);
752 		if (cb->s_oobflags & SF_SOOB) {
753 			/*
754 			 * Per jqj@cornell:
755 			 * make sure OB packets convey exactly 1 byte.
756 			 * If the packet is 1 byte or larger, we
757 			 * have already guaranted there to be at least
758 			 * one garbage byte for the checksum, and
759 			 * extra bytes shouldn't hurt!
760 			 */
761 			if (len > sizeof(*si)) {
762 				si->si_cc |= SP_OB;
763 				len = (1 + sizeof(*si));
764 			}
765 		}
766 		si->si_len = htons((u_short)len);
767 		/*
768 		 * queue stuff up for output
769 		 */
770 		sbappendrecord(sb, m);
771 		cb->s_seq++;
772 	}
773 	idle = (cb->s_smax == (cb->s_rack - 1));
774 again:
775 	sendalot = 0;
776 	off = cb->s_snxt - cb->s_rack;
777 	win = MIN(cb->s_swnd, (cb->s_cwnd/CUNIT));
778 
779 	/*
780 	 * If in persist timeout with window of 0, send a probe.
781 	 * Otherwise, if window is small but nonzero
782 	 * and timer expired, send what we can and go into
783 	 * transmit state.
784 	 */
785 	if (cb->s_force == 1 + TCPT_PERSIST) {
786 		if (win != 0) {
787 			cb->s_timer[TCPT_PERSIST] = 0;
788 			cb->s_rxtshift = 0;
789 		}
790 	}
791 	span = cb->s_seq - cb->s_rack;
792 	len = MIN(span, win) - off;
793 
794 	if (len < 0) {
795 		/*
796 		 * Window shrank after we went into it.
797 		 * If window shrank to 0, cancel pending
798 		 * restransmission and pull s_snxt back
799 		 * to (closed) window.  We will enter persist
800 		 * state below.  If the widndow didn't close completely,
801 		 * just wait for an ACK.
802 		 */
803 		len = 0;
804 		if (win == 0) {
805 			cb->s_timer[TCPT_REXMT] = 0;
806 			cb->s_snxt = cb->s_rack;
807 		}
808 	}
809 	if (len > 1)
810 		sendalot = 1;
811 	rcv_win = sbspace(&so->so_rcv);
812 
813 	/*
814 	 * Send if we owe peer an ACK.
815 	 */
816 	if (cb->s_oobflags & SF_SOOB) {
817 		/*
818 		 * must transmit this out of band packet
819 		 */
820 		cb->s_oobflags &= ~ SF_SOOB;
821 		sendalot = 1;
822 		sppstat.spps_sndurg++;
823 		goto found;
824 	}
825 	if (cb->s_flags & SF_ACKNOW)
826 		goto send;
827 	if (cb->s_state < TCPS_ESTABLISHED)
828 		goto send;
829 	/*
830 	 * Silly window can't happen in spp.
831 	 * Code from tcp deleted.
832 	 */
833 	if (len)
834 		goto send;
835 	/*
836 	 * Compare available window to amount of window
837 	 * known to peer (as advertised window less
838 	 * next expected input.)  If the difference is at least two
839 	 * packets or at least 35% of the mximum possible window,
840 	 * then want to send a window update to peer.
841 	 */
842 	if (rcv_win > 0) {
843 		u_short delta =  1 + cb->s_alo - cb->s_ack;
844 		int adv = rcv_win - (delta * cb->s_mtu);
845 
846 		if ((so->so_rcv.sb_cc == 0 && adv >= (2 * cb->s_mtu)) ||
847 		    (100 * adv / so->so_rcv.sb_hiwat >= 35)) {
848 			sppstat.spps_sndwinup++;
849 			cb->s_flags |= SF_ACKNOW;
850 			goto send;
851 		}
852 
853 	}
854 	/*
855 	 * Many comments from tcp_output.c are appropriate here
856 	 * including . . .
857 	 * If send window is too small, there is data to transmit, and no
858 	 * retransmit or persist is pending, then go to persist state.
859 	 * If nothing happens soon, send when timer expires:
860 	 * if window is nonzero, transmit what we can,
861 	 * otherwise send a probe.
862 	 */
863 	if (so->so_snd.sb_cc && cb->s_timer[TCPT_REXMT] == 0 &&
864 		cb->s_timer[TCPT_PERSIST] == 0) {
865 			cb->s_rxtshift = 0;
866 			spp_setpersist(cb);
867 	}
868 	/*
869 	 * No reason to send a packet, just return.
870 	 */
871 	cb->s_outx = 1;
872 	return (0);
873 
874 send:
875 	/*
876 	 * Find requested packet.
877 	 */
878 	si = 0;
879 	if (len > 0) {
880 		cb->s_want = cb->s_snxt;
881 		for (m = sb->sb_mb; m; m = m->m_act) {
882 			si = mtod(m, struct spidp *);
883 			if (SSEQ_LEQ(cb->s_snxt, si->si_seq))
884 				break;
885 		}
886 	found:
887 		if (si) {
888 			if (si->si_seq == cb->s_snxt)
889 					cb->s_snxt++;
890 				else
891 					sppstat.spps_sndvoid++, si = 0;
892 		}
893 	}
894 	/*
895 	 * update window
896 	 */
897 	if (rcv_win < 0)
898 		rcv_win = 0;
899 	oalo = alo = cb->s_ack - 1 + (rcv_win / ((short)cb->s_mtu));
900 	if (SSEQ_LT(alo, cb->s_alo))
901 		alo = cb->s_alo;
902 
903 	if (si) {
904 		/*
905 		 * must make a copy of this packet for
906 		 * idp_output to monkey with
907 		 */
908 		m = m_copy(dtom(si), 0, (int)M_COPYALL);
909 		if (m == NULL) {
910 			return (ENOBUFS);
911 		}
912 		m0 = m;
913 		si = mtod(m, struct spidp *);
914 		if (SSEQ_LT(si->si_seq, cb->s_smax))
915 			sppstat.spps_sndrexmitpack++;
916 		else
917 			sppstat.spps_sndpack++;
918 	} else if (cb->s_force || cb->s_flags & SF_ACKNOW) {
919 		/*
920 		 * Must send an acknowledgement or a probe
921 		 */
922 		if (cb->s_force)
923 			sppstat.spps_sndprobe++;
924 		if (cb->s_flags & SF_ACKNOW)
925 			sppstat.spps_sndacks++;
926 		m = m_get(M_DONTWAIT, MT_HEADER);
927 		if (m == 0) {
928 			return (ENOBUFS);
929 		}
930 		/*
931 		 * Fill in mbuf with extended SP header
932 		 * and addresses and length put into network format.
933 		 * Allign beginning of packet to long to prepend
934 		 * ifp's on loopback, or NSIP encaspulation for fussy cpu's.
935 		 */
936 		m->m_off = MMAXOFF - sizeof (struct spidp) - 2;
937 		m->m_len = sizeof (*si);
938 		m->m_next = 0;
939 		si = mtod(m, struct spidp *);
940 		si->si_i = *cb->s_idp;
941 		si->si_s = cb->s_shdr;
942 		si->si_seq = cb->s_smax + 1;
943 		si->si_len = htons(sizeof (*si));
944 		si->si_cc |= SP_SP;
945 	} else {
946 		cb->s_outx = 3;
947 		if (so->so_options & SO_DEBUG || traceallspps)
948 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
949 		return (0);
950 	}
951 	/*
952 	 * Stuff checksum and output datagram.
953 	 */
954 	if ((si->si_cc & SP_SP) == 0) {
955 		if (cb->s_force != (1 + TCPT_PERSIST) ||
956 		    cb->s_timer[TCPT_PERSIST] == 0) {
957 			/*
958 			 * If this is a new packet and we are not currently
959 			 * timing anything, time this one.
960 			 */
961 			if (SSEQ_LT(cb->s_smax, si->si_seq)) {
962 				cb->s_smax = si->si_seq;
963 				if (cb->s_rtt == 0) {
964 					sppstat.spps_segstimed++;
965 					cb->s_rtseq = si->si_seq;
966 					cb->s_rtt = 1;
967 				}
968 			}
969 			/*
970 			 * Set rexmt timer if not currently set,
971 			 * Initial value for retransmit timer is smoothed
972 			 * round-trip time + 2 * round-trip time variance.
973 			 * Initialize shift counter which is used for backoff
974 			 * of retransmit time.
975 			 */
976 			if (cb->s_timer[TCPT_REXMT] == 0 &&
977 			    cb->s_snxt != cb->s_rack) {
978 				cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
979 				if (cb->s_timer[TCPT_PERSIST]) {
980 					cb->s_timer[TCPT_PERSIST] = 0;
981 					cb->s_rxtshift = 0;
982 				}
983 			}
984 		} else if (SSEQ_LT(cb->s_smax, si->si_seq)) {
985 			cb->s_smax = si->si_seq;
986 		}
987 	} else if (cb->s_state < TCPS_ESTABLISHED) {
988 		if (cb->s_rtt == 0)
989 			cb->s_rtt = 1; /* Time initial handshake */
990 		if (cb->s_timer[TCPT_REXMT] == 0)
991 			cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
992 	}
993 	{
994 		/*
995 		 * Do not request acks when we ack their data packets or
996 		 * when we do a gratuitous window update.
997 		 */
998 		if (((si->si_cc & SP_SP) == 0) || cb->s_force)
999 				si->si_cc |= SP_SA;
1000 		si->si_seq = htons(si->si_seq);
1001 		si->si_alo = htons(alo);
1002 		si->si_ack = htons(cb->s_ack);
1003 
1004 		if (idpcksum) {
1005 			si->si_sum = 0;
1006 			len = ntohs(si->si_len);
1007 			if (len & 1)
1008 				len++;
1009 			si->si_sum = ns_cksum(dtom(si), len);
1010 		} else
1011 			si->si_sum = 0xffff;
1012 
1013 		cb->s_outx = 4;
1014 		if (so->so_options & SO_DEBUG || traceallspps)
1015 			spp_trace(SA_OUTPUT, cb->s_state, cb, si, 0);
1016 
1017 		if (so->so_options & SO_DONTROUTE)
1018 			error = ns_output(m, (struct route *)0, NS_ROUTETOIF);
1019 		else
1020 			error = ns_output(m, &cb->s_nspcb->nsp_route, 0);
1021 	}
1022 	if (error) {
1023 		return (error);
1024 	}
1025 	sppstat.spps_sndtotal++;
1026 	/*
1027 	 * Data sent (as far as we can tell).
1028 	 * If this advertises a larger window than any other segment,
1029 	 * then remember the size of the advertized window.
1030 	 * Any pending ACK has now been sent.
1031 	 */
1032 	cb->s_force = 0;
1033 	cb->s_flags &= ~(SF_ACKNOW|SF_DELACK);
1034 	if (SSEQ_GT(alo, cb->s_alo))
1035 		cb->s_alo = alo;
1036 	if (sendalot)
1037 		goto again;
1038 	cb->s_outx = 5;
1039 	return (0);
1040 }
1041 
1042 int spp_do_persist_panics = 0;
1043 
1044 spp_setpersist(cb)
1045 	register struct sppcb *cb;
1046 {
1047 	register t = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1048 	extern int spp_backoff[];
1049 
1050 	if (cb->s_timer[TCPT_REXMT] && spp_do_persist_panics)
1051 		panic("spp_output REXMT");
1052 	/*
1053 	 * Start/restart persistance timer.
1054 	 */
1055 	TCPT_RANGESET(cb->s_timer[TCPT_PERSIST],
1056 	    t*spp_backoff[cb->s_rxtshift],
1057 	    TCPTV_PERSMIN, TCPTV_PERSMAX);
1058 	if (cb->s_rxtshift < TCP_MAXRXTSHIFT)
1059 		cb->s_rxtshift++;
1060 }
1061 /*ARGSUSED*/
1062 spp_ctloutput(req, so, level, name, value)
1063 	int req;
1064 	struct socket *so;
1065 	int name;
1066 	struct mbuf **value;
1067 {
1068 	register struct mbuf *m;
1069 	struct nspcb *nsp = sotonspcb(so);
1070 	register struct sppcb *cb;
1071 	int mask, error = 0;
1072 
1073 	if (level != NSPROTO_SPP) {
1074 		/* This will have to be changed when we do more general
1075 		   stacking of protocols */
1076 		return (idp_ctloutput(req, so, level, name, value));
1077 	}
1078 	if (nsp == NULL) {
1079 		error = EINVAL;
1080 		goto release;
1081 	} else
1082 		cb = nstosppcb(nsp);
1083 
1084 	switch (req) {
1085 
1086 	case PRCO_GETOPT:
1087 		if (value == NULL)
1088 			return (EINVAL);
1089 		m = m_get(M_DONTWAIT, MT_DATA);
1090 		if (m == NULL)
1091 			return (ENOBUFS);
1092 		switch (name) {
1093 
1094 		case SO_HEADERS_ON_INPUT:
1095 			mask = SF_HI;
1096 			goto get_flags;
1097 
1098 		case SO_HEADERS_ON_OUTPUT:
1099 			mask = SF_HO;
1100 		get_flags:
1101 			m->m_len = sizeof(short);
1102 			m->m_off = MMAXOFF - sizeof(short);
1103 			*mtod(m, short *) = cb->s_flags & mask;
1104 			break;
1105 
1106 		case SO_MTU:
1107 			m->m_len = sizeof(u_short);
1108 			m->m_off = MMAXOFF - sizeof(short);
1109 			*mtod(m, short *) = cb->s_mtu;
1110 			break;
1111 
1112 		case SO_LAST_HEADER:
1113 			m->m_len = sizeof(struct sphdr);
1114 			m->m_off = MMAXOFF - sizeof(struct sphdr);
1115 			*mtod(m, struct sphdr *) = cb->s_rhdr;
1116 			break;
1117 
1118 		case SO_DEFAULT_HEADERS:
1119 			m->m_len = sizeof(struct spidp);
1120 			m->m_off = MMAXOFF - sizeof(struct sphdr);
1121 			*mtod(m, struct sphdr *) = cb->s_shdr;
1122 			break;
1123 
1124 		default:
1125 			error = EINVAL;
1126 		}
1127 		*value = m;
1128 		break;
1129 
1130 	case PRCO_SETOPT:
1131 		if (value == 0 || *value == 0) {
1132 			error = EINVAL;
1133 			break;
1134 		}
1135 		switch (name) {
1136 			int *ok;
1137 
1138 		case SO_HEADERS_ON_INPUT:
1139 			mask = SF_HI;
1140 			goto set_head;
1141 
1142 		case SO_HEADERS_ON_OUTPUT:
1143 			mask = SF_HO;
1144 		set_head:
1145 			if (cb->s_flags & SF_PI) {
1146 				ok = mtod(*value, int *);
1147 				if (*ok)
1148 					cb->s_flags |= mask;
1149 				else
1150 					cb->s_flags &= ~mask;
1151 			} else error = EINVAL;
1152 			break;
1153 
1154 		case SO_MTU:
1155 			cb->s_mtu = *(mtod(*value, u_short *));
1156 			break;
1157 
1158 		case SO_DEFAULT_HEADERS:
1159 			{
1160 				register struct sphdr *sp
1161 						= mtod(*value, struct sphdr *);
1162 				cb->s_dt = sp->sp_dt;
1163 				cb->s_cc = sp->sp_cc & SP_EM;
1164 			}
1165 			break;
1166 
1167 		default:
1168 			error = EINVAL;
1169 		}
1170 		m_freem(*value);
1171 		break;
1172 	}
1173 	release:
1174 		return (error);
1175 }
1176 
1177 /*ARGSUSED*/
1178 spp_usrreq(so, req, m, nam, rights)
1179 	struct socket *so;
1180 	int req;
1181 	struct mbuf *m, *nam, *rights;
1182 {
1183 	struct nspcb *nsp = sotonspcb(so);
1184 	register struct sppcb *cb;
1185 	int s = splnet();
1186 	int error = 0, ostate;
1187 	struct mbuf *mm;
1188 	register struct sockbuf *sb;
1189 
1190 	if (req == PRU_CONTROL)
1191                 return (ns_control(so, (int)m, (caddr_t)nam,
1192 			(struct ifnet *)rights));
1193 	if (rights && rights->m_len) {
1194 		error = EINVAL;
1195 		goto release;
1196 	}
1197 	if (nsp == NULL) {
1198 		if (req != PRU_ATTACH) {
1199 			error = EINVAL;
1200 			goto release;
1201 		}
1202 	} else
1203 		cb = nstosppcb(nsp);
1204 
1205 	ostate = cb ? cb->s_state : 0;
1206 
1207 	switch (req) {
1208 
1209 	case PRU_ATTACH:
1210 		if (nsp != NULL) {
1211 			error = EISCONN;
1212 			break;
1213 		}
1214 		error = ns_pcballoc(so, &nspcb);
1215 		if (error)
1216 			break;
1217 		error = soreserve(so, 3072, 3072);
1218 		if (error)
1219 			break;
1220 		nsp = sotonspcb(so);
1221 
1222 		mm = m_getclr(M_DONTWAIT, MT_PCB);
1223 		sb = &so->so_snd;
1224 
1225 		if (mm == NULL) {
1226 			error = ENOBUFS;
1227 			break;
1228 		}
1229 		cb = mtod(mm, struct sppcb *);
1230 		mm = m_getclr(M_DONTWAIT, MT_HEADER);
1231 		if (mm == NULL) {
1232 			m_free(dtom(m));
1233 			error = ENOBUFS;
1234 			break;
1235 		}
1236 		cb->s_idp = mtod(mm, struct idp *);
1237 		cb->s_state = TCPS_LISTEN;
1238 		cb->s_smax = -1;
1239 		cb->s_swl1 = -1;
1240 		cb->s_q.si_next = cb->s_q.si_prev = &cb->s_q;
1241 		cb->s_nspcb = nsp;
1242 		cb->s_mtu = 576 - sizeof (struct spidp);
1243 		cb->s_cwnd = sbspace(sb) * CUNIT / cb->s_mtu;
1244 		cb->s_ssthresh = cb->s_cwnd;
1245 		cb->s_cwmx = sb->sb_mbmax * CUNIT /
1246 				(2 * sizeof (struct spidp));
1247 		/* Above is recomputed when connecting to account
1248 		   for changed buffering or mtu's */
1249 		cb->s_rtt = TCPTV_SRTTBASE;
1250 		cb->s_rttvar = TCPTV_SRTTDFLT << 2;
1251 		TCPT_RANGESET(cb->s_rxtcur,
1252 		    ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
1253 		    TCPTV_MIN, TCPTV_REXMTMAX);
1254 		nsp->nsp_pcb = (caddr_t) cb;
1255 		break;
1256 
1257 	case PRU_DETACH:
1258 		if (nsp == NULL) {
1259 			error = ENOTCONN;
1260 			break;
1261 		}
1262 		if (cb->s_state > TCPS_LISTEN)
1263 			cb = spp_disconnect(cb);
1264 		else
1265 			cb = spp_close(cb);
1266 		break;
1267 
1268 	case PRU_BIND:
1269 		error = ns_pcbbind(nsp, nam);
1270 		break;
1271 
1272 	case PRU_LISTEN:
1273 		if (nsp->nsp_lport == 0)
1274 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1275 		if (error == 0)
1276 			cb->s_state = TCPS_LISTEN;
1277 		break;
1278 
1279 	/*
1280 	 * Initiate connection to peer.
1281 	 * Enter SYN_SENT state, and mark socket as connecting.
1282 	 * Start keep-alive timer, setup prototype header,
1283 	 * Send initial system packet requesting connection.
1284 	 */
1285 	case PRU_CONNECT:
1286 		if (nsp->nsp_lport == 0) {
1287 			error = ns_pcbbind(nsp, (struct mbuf *)0);
1288 			if (error)
1289 				break;
1290 		}
1291 		error = ns_pcbconnect(nsp, nam);
1292 		if (error)
1293 			break;
1294 		soisconnecting(so);
1295 		sppstat.spps_connattempt++;
1296 		cb->s_state = TCPS_SYN_SENT;
1297 		cb->s_did = 0;
1298 		spp_template(cb);
1299 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
1300 		cb->s_force = 1 + TCPTV_KEEP;
1301 		/*
1302 		 * Other party is required to respond to
1303 		 * the port I send from, but he is not
1304 		 * required to answer from where I am sending to,
1305 		 * so allow wildcarding.
1306 		 * original port I am sending to is still saved in
1307 		 * cb->s_dport.
1308 		 */
1309 		nsp->nsp_fport = 0;
1310 		error = spp_output(cb, (struct mbuf *) 0);
1311 		break;
1312 
1313 	case PRU_CONNECT2:
1314 		error = EOPNOTSUPP;
1315 		break;
1316 
1317 	/*
1318 	 * We may decide later to implement connection closing
1319 	 * handshaking at the spp level optionally.
1320 	 * here is the hook to do it:
1321 	 */
1322 	case PRU_DISCONNECT:
1323 		cb = spp_disconnect(cb);
1324 		break;
1325 
1326 	/*
1327 	 * Accept a connection.  Essentially all the work is
1328 	 * done at higher levels; just return the address
1329 	 * of the peer, storing through addr.
1330 	 */
1331 	case PRU_ACCEPT: {
1332 		struct sockaddr_ns *sns = mtod(nam, struct sockaddr_ns *);
1333 
1334 		nam->m_len = sizeof (struct sockaddr_ns);
1335 		sns->sns_family = AF_NS;
1336 		sns->sns_addr = nsp->nsp_faddr;
1337 		break;
1338 		}
1339 
1340 	case PRU_SHUTDOWN:
1341 		socantsendmore(so);
1342 		cb = spp_usrclosed(cb);
1343 		if (cb)
1344 			error = spp_output(cb, (struct mbuf *) 0);
1345 		break;
1346 
1347 	/*
1348 	 * After a receive, possibly send acknowledgment
1349 	 * updating allocation.
1350 	 */
1351 	case PRU_RCVD:
1352 		cb->s_flags |= SF_RVD;
1353 		(void) spp_output(cb, (struct mbuf *) 0);
1354 		cb->s_flags &= ~SF_RVD;
1355 		break;
1356 
1357 	case PRU_ABORT:
1358 		(void) spp_drop(cb, ECONNABORTED);
1359 		break;
1360 
1361 	case PRU_SENSE:
1362 	case PRU_CONTROL:
1363 		m = NULL;
1364 		error = EOPNOTSUPP;
1365 		break;
1366 
1367 	case PRU_RCVOOB:
1368 		if ((cb->s_oobflags & SF_IOOB) || so->so_oobmark ||
1369 		    (so->so_state & SS_RCVATMARK)) {
1370 			m->m_len = 1;
1371 			*mtod(m, caddr_t) = cb->s_iobc;
1372 			break;
1373 		}
1374 		error = EINVAL;
1375 		break;
1376 
1377 	case PRU_SENDOOB:
1378 		if (sbspace(&so->so_snd) < -512) {
1379 			error = ENOBUFS;
1380 			break;
1381 		}
1382 		cb->s_oobflags |= SF_SOOB;
1383 		/* fall into */
1384 	case PRU_SEND:
1385 		error = spp_output(cb, m);
1386 		m = NULL;
1387 		break;
1388 
1389 	case PRU_SOCKADDR:
1390 		ns_setsockaddr(nsp, nam);
1391 		break;
1392 
1393 	case PRU_PEERADDR:
1394 		ns_setpeeraddr(nsp, nam);
1395 		break;
1396 
1397 	case PRU_SLOWTIMO:
1398 		cb = spp_timers(cb, (int)nam);
1399 		req |= ((int)nam) << 8;
1400 		break;
1401 
1402 	case PRU_FASTTIMO:
1403 	case PRU_PROTORCV:
1404 	case PRU_PROTOSEND:
1405 		error =  EOPNOTSUPP;
1406 		break;
1407 
1408 	default:
1409 		panic("sp_usrreq");
1410 	}
1411 	if (cb && (so->so_options & SO_DEBUG || traceallspps))
1412 		spp_trace(SA_USER, (u_char)ostate, cb, (struct spidp *)0, req);
1413 release:
1414 	if (m != NULL)
1415 		m_freem(m);
1416 	splx(s);
1417 	return (error);
1418 }
1419 
1420 spp_usrreq_sp(so, req, m, nam, rights)
1421 	struct socket *so;
1422 	int req;
1423 	struct mbuf *m, *nam, *rights;
1424 {
1425 	int error = spp_usrreq(so, req, m, nam, rights);
1426 
1427 	if (req == PRU_ATTACH && error == 0) {
1428 		struct nspcb *nsp = sotonspcb(so);
1429 		((struct sppcb *)nsp->nsp_pcb)->s_flags |=
1430 					(SF_HI | SF_HO | SF_PI);
1431 	}
1432 	return (error);
1433 }
1434 
1435 /*
1436  * Create template to be used to send spp packets on a connection.
1437  * Called after host entry created, fills
1438  * in a skeletal spp header (choosing connection id),
1439  * minimizing the amount of work necessary when the connection is used.
1440  */
1441 spp_template(cb)
1442 	register struct sppcb *cb;
1443 {
1444 	register struct nspcb *nsp = cb->s_nspcb;
1445 	register struct idp *idp = cb->s_idp;
1446 	register struct sockbuf *sb = &(nsp->nsp_socket->so_snd);
1447 
1448 	idp->idp_pt = NSPROTO_SPP;
1449 	idp->idp_sna = nsp->nsp_laddr;
1450 	idp->idp_dna = nsp->nsp_faddr;
1451 	cb->s_sid = htons(spp_iss);
1452 	spp_iss += SPP_ISSINCR/2;
1453 	cb->s_alo = 1;
1454 	cb->s_cwnd = (sbspace(sb) * CUNIT) / cb->s_mtu;
1455 	cb->s_ssthresh = cb->s_cwnd; /* Try to expand fast to full complement
1456 					of large packets */
1457 	cb->s_cwmx = (sb->sb_mbmax * CUNIT) / (2 * sizeof(struct spidp));
1458 	cb->s_cwmx = MAX(cb->s_cwmx, cb->s_cwnd);
1459 		/* But allow for lots of little packets as well */
1460 }
1461 
1462 /*
1463  * Close a SPIP control block:
1464  *	discard spp control block itself
1465  *	discard ns protocol control block
1466  *	wake up any sleepers
1467  */
1468 struct sppcb *
1469 spp_close(cb)
1470 	register struct sppcb *cb;
1471 {
1472 	register struct spidp_q *s;
1473 	struct nspcb *nsp = cb->s_nspcb;
1474 	struct socket *so = nsp->nsp_socket;
1475 	register struct mbuf *m;
1476 
1477 	s = cb->s_q.si_next;
1478 	while (s != &(cb->s_q)) {
1479 		s = s->si_next;
1480 		m = dtom(s->si_prev);
1481 		remque(s->si_prev);
1482 		m_freem(m);
1483 	}
1484 	(void) m_free(dtom(cb->s_idp));
1485 	(void) m_free(dtom(cb));
1486 	nsp->nsp_pcb = 0;
1487 	soisdisconnected(so);
1488 	ns_pcbdetach(nsp);
1489 	sppstat.spps_closed++;
1490 	return ((struct sppcb *)0);
1491 }
1492 /*
1493  *	Someday we may do level 3 handshaking
1494  *	to close a connection or send a xerox style error.
1495  *	For now, just close.
1496  */
1497 struct sppcb *
1498 spp_usrclosed(cb)
1499 	register struct sppcb *cb;
1500 {
1501 	return (spp_close(cb));
1502 }
1503 struct sppcb *
1504 spp_disconnect(cb)
1505 	register struct sppcb *cb;
1506 {
1507 	return (spp_close(cb));
1508 }
1509 /*
1510  * Drop connection, reporting
1511  * the specified error.
1512  */
1513 struct sppcb *
1514 spp_drop(cb, errno)
1515 	register struct sppcb *cb;
1516 	int errno;
1517 {
1518 	struct socket *so = cb->s_nspcb->nsp_socket;
1519 
1520 	/*
1521 	 * someday, in the xerox world
1522 	 * we will generate error protocol packets
1523 	 * announcing that the socket has gone away.
1524 	 */
1525 	if (TCPS_HAVERCVDSYN(cb->s_state)) {
1526 		sppstat.spps_drops++;
1527 		cb->s_state = TCPS_CLOSED;
1528 		/*(void) tcp_output(cb);*/
1529 	} else
1530 		sppstat.spps_conndrops++;
1531 	so->so_error = errno;
1532 	return (spp_close(cb));
1533 }
1534 
1535 spp_abort(nsp)
1536 	struct nspcb *nsp;
1537 {
1538 
1539 	(void) spp_close((struct sppcb *)nsp->nsp_pcb);
1540 }
1541 
1542 long	spp_backoff[TCP_MAXRXTSHIFT+1] =
1543     { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
1544 /*
1545  * Fast timeout routine for processing delayed acks
1546  */
1547 spp_fasttimo()
1548 {
1549 	register struct nspcb *nsp;
1550 	register struct sppcb *cb;
1551 	int s = splnet();
1552 
1553 	nsp = nspcb.nsp_next;
1554 	if (nsp)
1555 	for (; nsp != &nspcb; nsp = nsp->nsp_next)
1556 		if ((cb = (struct sppcb *)nsp->nsp_pcb) &&
1557 		    (cb->s_flags & SF_DELACK)) {
1558 			cb->s_flags &= ~SF_DELACK;
1559 			cb->s_flags |= SF_ACKNOW;
1560 			sppstat.spps_delack++;
1561 			(void) spp_output(cb, (struct mbuf *) 0);
1562 		}
1563 	splx(s);
1564 }
1565 
1566 /*
1567  * spp protocol timeout routine called every 500 ms.
1568  * Updates the timers in all active pcb's and
1569  * causes finite state machine actions if timers expire.
1570  */
1571 spp_slowtimo()
1572 {
1573 	register struct nspcb *ip, *ipnxt;
1574 	register struct sppcb *cb;
1575 	int s = splnet();
1576 	register int i;
1577 
1578 	/*
1579 	 * Search through tcb's and update active timers.
1580 	 */
1581 	ip = nspcb.nsp_next;
1582 	if (ip == 0) {
1583 		splx(s);
1584 		return;
1585 	}
1586 	while (ip != &nspcb) {
1587 		cb = nstosppcb(ip);
1588 		ipnxt = ip->nsp_next;
1589 		if (cb == 0)
1590 			goto tpgone;
1591 		for (i = 0; i < TCPT_NTIMERS; i++) {
1592 			if (cb->s_timer[i] && --cb->s_timer[i] == 0) {
1593 				(void) spp_usrreq(cb->s_nspcb->nsp_socket,
1594 				    PRU_SLOWTIMO, (struct mbuf *)0,
1595 				    (struct mbuf *)i, (struct mbuf *)0);
1596 				if (ipnxt->nsp_prev != ip)
1597 					goto tpgone;
1598 			}
1599 		}
1600 		cb->s_idle++;
1601 		if (cb->s_rtt)
1602 			cb->s_rtt++;
1603 tpgone:
1604 		ip = ipnxt;
1605 	}
1606 	spp_iss += SPP_ISSINCR/PR_SLOWHZ;		/* increment iss */
1607 	splx(s);
1608 }
1609 /*
1610  * SPP timer processing.
1611  */
1612 struct sppcb *
1613 spp_timers(cb, timer)
1614 	register struct sppcb *cb;
1615 	int timer;
1616 {
1617 	long rexmt;
1618 	int win;
1619 
1620 	cb->s_force = 1 + timer;
1621 	switch (timer) {
1622 
1623 	/*
1624 	 * 2 MSL timeout in shutdown went off.  TCP deletes connection
1625 	 * control block.
1626 	 */
1627 	case TCPT_2MSL:
1628 		printf("spp: TCPT_2MSL went off for no reason\n");
1629 		cb->s_timer[timer] = 0;
1630 		break;
1631 
1632 	/*
1633 	 * Retransmission timer went off.  Message has not
1634 	 * been acked within retransmit interval.  Back off
1635 	 * to a longer retransmit interval and retransmit one packet.
1636 	 */
1637 	case TCPT_REXMT:
1638 		if (++cb->s_rxtshift > TCP_MAXRXTSHIFT) {
1639 			cb->s_rxtshift = TCP_MAXRXTSHIFT;
1640 			sppstat.spps_timeoutdrop++;
1641 			cb = spp_drop(cb, ETIMEDOUT);
1642 			break;
1643 		}
1644 		sppstat.spps_rexmttimeo++;
1645 		rexmt = ((cb->s_srtt >> 2) + cb->s_rttvar) >> 1;
1646 		rexmt *= spp_backoff[cb->s_rxtshift];
1647 		TCPT_RANGESET(cb->s_rxtcur, rexmt, TCPTV_MIN, TCPTV_REXMTMAX);
1648 		cb->s_timer[TCPT_REXMT] = cb->s_rxtcur;
1649 		/*
1650 		 * If we have backed off fairly far, our srtt
1651 		 * estimate is probably bogus.  Clobber it
1652 		 * so we'll take the next rtt measurement as our srtt;
1653 		 * move the current srtt into rttvar to keep the current
1654 		 * retransmit times until then.
1655 		 */
1656 		if (cb->s_rxtshift > TCP_MAXRXTSHIFT / 4 ) {
1657 			cb->s_rttvar += (cb->s_srtt >> 2);
1658 			cb->s_srtt = 0;
1659 		}
1660 		cb->s_snxt = cb->s_rack;
1661 		/*
1662 		 * If timing a packet, stop the timer.
1663 		 */
1664 		cb->s_rtt = 0;
1665 		/*
1666 		 * See very long discussion in tcp_timer.c about congestion
1667 		 * window and sstrhesh
1668 		 */
1669 		win = MIN(cb->s_swnd, (cb->s_cwnd/CUNIT)) / 2;
1670 		if (win < 2)
1671 			win = 2;
1672 		cb->s_cwnd = CUNIT;
1673 		cb->s_ssthresh = win;
1674 		(void) spp_output(cb, (struct mbuf *) 0);
1675 		break;
1676 
1677 	/*
1678 	 * Persistance timer into zero window.
1679 	 * Force a probe to be sent.
1680 	 */
1681 	case TCPT_PERSIST:
1682 		sppstat.spps_persisttimeo++;
1683 		spp_setpersist(cb);
1684 		(void) spp_output(cb, (struct mbuf *) 0);
1685 		break;
1686 
1687 	/*
1688 	 * Keep-alive timer went off; send something
1689 	 * or drop connection if idle for too long.
1690 	 */
1691 	case TCPT_KEEP:
1692 		sppstat.spps_keeptimeo++;
1693 		if (cb->s_state < TCPS_ESTABLISHED)
1694 			goto dropit;
1695 		if (cb->s_nspcb->nsp_socket->so_options & SO_KEEPALIVE) {
1696 		    	if (cb->s_idle >= TCPTV_MAXIDLE)
1697 				goto dropit;
1698 			sppstat.spps_keepprobe++;
1699 			(void) spp_output(cb, (struct mbuf *) 0);
1700 		} else
1701 			cb->s_idle = 0;
1702 		cb->s_timer[TCPT_KEEP] = TCPTV_KEEP;
1703 		break;
1704 	dropit:
1705 		sppstat.spps_keepdrops++;
1706 		cb = spp_drop(cb, ETIMEDOUT);
1707 		break;
1708 	}
1709 	return (cb);
1710 }
1711 int SppcbSize = sizeof (struct sppcb);
1712 int NspcbSize = sizeof (struct nspcb);
1713