xref: /plan9/sys/src/cmd/ip/dhcpd/dhcpd.c (revision 8deabd962e84f51c67a12f970084955d97d8a8f2)
1 #include <u.h>
2 #include <libc.h>
3 #include <ip.h>
4 #include <bio.h>
5 #include <ndb.h>
6 #include "dat.h"
7 
8 /*
9  *	ala rfc2131
10  */
11 
12 enum {
13 	Maxloglen = 1024,
14 };
15 
16 typedef struct Req Req;
17 struct Req
18 {
19 	int	fd;			/* for reply */
20 	Bootp	*bp;
21 	Udphdr	*up;
22 	uchar	*e;			/* end of received message */
23 	uchar	*p;			/* options pointer */
24 	uchar	*max;			/* max end of reply */
25 
26 	/* expanded to v6 */
27 	uchar	ciaddr[IPaddrlen];
28 	uchar	giaddr[IPaddrlen];
29 
30 	/* parsed options */
31 	int	p9request;		/* flag: this is a bootp with plan9 options */
32 	int	genrequest;		/* flag: this is a bootp with generic options */
33 	int	dhcptype;		/* dhcp message type */
34 	int	leasetime;		/* dhcp lease */
35 	uchar	ip[IPaddrlen];		/* requested address */
36 	uchar	server[IPaddrlen];	/* server address */
37 	char	msg[ERRMAX];		/* error message */
38 	char	vci[32];		/* vendor class id */
39 	char	*id;			/* client id */
40 	uchar	requested[32];		/* requested params */
41 	uchar	vendorclass[32];
42 	char	cputype[32-3];
43 
44 	Info	gii;			/* about target network */
45 	Info	ii;			/* about target system */
46 	int	staticbinding;
47 
48 	uchar buf[2*1024];		/* message buffer */
49 };
50 
51 #define TFTP "/lib/tftpd"
52 
53 char	*blog = "ipboot";
54 char	mysysname[64];
55 Ipifc	*ipifcs;
56 int	debug;
57 int	nobootp;
58 long	now;
59 int	slowstat, slowdyn;
60 char	net[256];
61 
62 int	pptponly;	/* only answer request that came from the pptp server */
63 int	mute, mutestat;
64 int	minlease = MinLease;
65 int	staticlease = StaticLease;
66 
67 ulong	start;
68 
69 static int v6opts;
70 
71 /* option magic */
72 char plan9opt[4] = { 'p', '9', ' ', ' ' };
73 char genericopt[4] = { 0x63, 0x82, 0x53, 0x63 };
74 
75 /* well known addresses */
76 uchar zeros[Maxhwlen];
77 
78 /* option debug buffer */
79 char optbuf[1024];
80 char *op;
81 char *oe = optbuf + sizeof(optbuf);
82 
83 char *optname[256] =
84 {
85 [OBend]			"end",
86 [OBpad]			"pad",
87 [OBmask]		"mask",
88 [OBtimeoff]		"timeoff",
89 [OBrouter]		"router",
90 [OBtimeserver]		"time",
91 [OBnameserver]		"name",
92 [OBdnserver]		"dns",
93 [OBlogserver]		"log",
94 [OBcookieserver]	"cookie",
95 [OBlprserver]		"lpr",
96 [OBimpressserver]	"impress",
97 [OBrlserver]		"rl",
98 [OBhostname]		"host",
99 [OBbflen]		"bflen",
100 [OBdumpfile]		"dumpfile",
101 [OBdomainname]		"dom",
102 [OBswapserver]		"swap",
103 [OBrootpath]		"rootpath",
104 [OBextpath]		"extpath",
105 [OBipforward]		"ipforward",
106 [OBnonlocal]		"nonlocal",
107 [OBpolicyfilter]	"policyfilter",
108 [OBmaxdatagram]		"maxdatagram",
109 [OBttl]			"ttl",
110 [OBpathtimeout]		"pathtimeout",
111 [OBpathplateau]		"pathplateau",
112 [OBmtu]			"mtu",
113 [OBsubnetslocal]	"subnetslocal",
114 [OBbaddr]		"baddr",
115 [OBdiscovermask]	"discovermask",
116 [OBsupplymask]		"supplymask",
117 [OBdiscoverrouter]	"discoverrouter",
118 [OBrsserver]		"rsserver",
119 [OBstaticroutes]	"staticroutes",
120 [OBtrailerencap]	"trailerencap",
121 [OBarptimeout]		"arptimeout",
122 [OBetherencap]		"etherencap",
123 [OBtcpttl]		"tcpttl",
124 [OBtcpka]		"tcpka",
125 [OBtcpkag]		"tcpkag",
126 [OBnisdomain]		"nisdomain",
127 [OBniserver]		"niserver",
128 [OBntpserver]		"ntpserver",
129 [OBvendorinfo]		"vendorinfo",
130 [OBnetbiosns]		"NBns",
131 [OBnetbiosdds]		"NBdds",
132 [OBnetbiostype]		"NBtype",
133 [OBnetbiosscope]	"NBscope",
134 [OBxfontserver]		"xfont",
135 [OBxdispmanager]	"xdisp",
136 [OBnisplusdomain]	"NPdomain",
137 [OBnisplusserver]	"NP",
138 [OBhomeagent]		"homeagent",
139 [OBsmtpserver]		"smtp",
140 [OBpop3server]		"pop3",
141 [OBnntpserver]		"nntp",
142 [OBwwwserver]		"www",
143 [OBfingerserver]	"finger",
144 [OBircserver]		"ircserver",
145 [OBstserver]		"stserver",
146 [OBstdaserver]		"stdaserver",
147 
148 /* dhcp options */
149 [ODipaddr]		"ip",
150 [ODlease]		"leas",
151 [ODoverload]		"overload",
152 [ODtype]		"typ",
153 [ODserverid]		"sid",
154 [ODparams]		"params",
155 [ODmessage]		"message",
156 [ODmaxmsg]		"maxmsg",
157 [ODrenewaltime]		"renewaltime",
158 [ODrebindingtime]	"rebindingtime",
159 [ODvendorclass]		"vendorclass",
160 [ODclientid]		"cid",
161 [ODtftpserver]		"tftpserver",
162 [ODbootfile]		"bf",
163 };
164 
165 void	addropt(Req*, int, uchar*);
166 void	addrsopt(Req*, int, uchar**, int);
167 void	arpenter(uchar*, uchar*);
168 void	bootp(Req*);
169 void	byteopt(Req*, int, uchar);
170 void	dhcp(Req*);
171 void	fatal(int, char*, ...);
172 void	hexopt(Req*, int, char*);
173 void	logdhcp(Req*);
174 void	logdhcpout(Req *, char *);
175 void	longopt(Req*, int, long);
176 void	maskopt(Req*, int, uchar*);
177 void	miscoptions(Req*, uchar*);
178 int	openlisten(char *net);
179 void	p9addrsopt(Req *rp, int t, uchar **ip, int i);
180 void	parseoptions(Req*);
181 void	proto(Req*, int);
182 void	rcvdecline(Req*);
183 void	rcvdiscover(Req*);
184 void	rcvinform(Req*);
185 void	rcvrelease(Req*);
186 void	rcvrequest(Req*);
187 int	readlast(int, uchar*, int);
188 char*	readsysname(void);
189 void	remrequested(Req*, int);
190 void	sendack(Req*, uchar*, int, int);
191 void	sendnak(Req*, char*);
192 void	sendoffer(Req*, uchar*, int);
193 void	stringopt(Req*, int, char*);
194 void	termopt(Req*);
195 int	validip(uchar*);
196 void	vectoropt(Req*, int, uchar*, int);
197 void	warning(int, char*, ...);
198 
199 void
200 timestamp(char *tag)
201 {
202 	ulong t;
203 
204 	t = nsec()/1000;
205 	syslog(0, blog, "%s %lud", tag, t - start);
206 }
207 
208 void
209 usage(void)
210 {
211 	fprint(2, "usage: dhcp [-dmnprsSZ] [-f directory] [-M minlease] "
212 		"[-x netmtpt] [-Z staticlease] addr n [addr n] ...\n");
213 	exits("usage");
214 }
215 
216 void
217 main(int argc, char **argv)
218 {
219 	int i, n, fd;
220 	uchar ip[IPaddrlen];
221 	Req r;
222 
223 	setnetmtpt(net, sizeof net, nil);
224 
225 	fmtinstall('E', eipfmt);
226 	fmtinstall('I', eipfmt);
227 	fmtinstall('V', eipfmt);
228 	fmtinstall('M', eipfmt);
229 	ARGBEGIN {
230 	case '6':
231 		v6opts = 1;
232 		break;
233 	case 'd':
234 		debug = 1;
235 		break;
236 	case 'f':
237 		ndbfile = EARGF(usage());
238 		break;
239 	case 'm':
240 		mute = 1;
241 		break;
242 	case 'M':
243 		minlease = atoi(EARGF(usage()));
244 		if(minlease <= 0)
245 			minlease = MinLease;
246 		break;
247 	case 'n':
248 		nobootp = 1;
249 		break;
250 	case 'p':
251 		pptponly = 1;
252 		break;
253 	case 'r':
254 		mutestat = 1;
255 		break;
256 	case 's':
257 		slowstat = 1;
258 		break;
259 	case 'S':
260 		slowdyn = 1;
261 		break;
262 	case 'x':
263 		setnetmtpt(net, sizeof net, EARGF(usage()));
264 		break;
265 	case 'Z':
266 		staticlease = atoi(EARGF(usage()));
267 		if(staticlease <= 0)
268 			staticlease = StaticLease;
269 		break;
270 	default:
271 		usage();
272 		break;
273 	} ARGEND;
274 
275 	while(argc > 1){
276 		parseip(ip, argv[0]);
277 		if(!validip(ip))
278 			usage();
279 		n = atoi(argv[1]);
280 		if(n <= 0)
281 			usage();
282 		initbinding(ip, n);
283 		argc -= 2;
284 		argv += 2;
285 	}
286 
287 	/* for debugging */
288 	for(i = 0; i < 256; i++)
289 		if(optname[i] == 0)
290 			optname[i] = smprint("%d", i);
291 
292 	/* what is my name? */
293 	strcpy(mysysname, readsysname());
294 
295 	/* put process in background */
296 	if(!debug)
297 	switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
298 	case -1:
299 		fatal(1, "fork");
300 	case 0:
301 		break;
302 	default:
303 		exits(0);
304 	}
305 
306 	chdir(TFTP);
307 	fd = openlisten(net);
308 
309 	for(;;){
310 		memset(&r, 0, sizeof(r));
311 		r.fd = fd;
312 		n = readlast(r.fd, r.buf, sizeof(r.buf));
313 		if(n < Udphdrsize)
314 			fatal(1, "error reading requests");
315 		start = nsec()/1000;
316 		op = optbuf;
317 		*op = 0;
318 		proto(&r, n);
319 		if(r.id != nil)
320 			free(r.id);
321 	}
322 }
323 
324 void
325 proto(Req *rp, int n)
326 {
327 	uchar relip[IPaddrlen];
328 	char buf[64];
329 
330 	now = time(0);
331 
332 	rp->e = rp->buf + n;
333 	rp->bp = (Bootp*)rp->buf;
334 	rp->up = (Udphdr*)rp->buf;
335 	if (ipcmp(rp->up->laddr, IPv4bcast) == 0)
336 		ipmove(rp->up->laddr, rp->up->ifcaddr);
337 	rp->max = rp->buf + Udphdrsize + MINSUPPORTED - IPUDPHDRSIZE;
338 	rp->p = rp->bp->optdata;
339 	v4tov6(rp->giaddr, rp->bp->giaddr);
340 	v4tov6(rp->ciaddr, rp->bp->ciaddr);
341 
342 	if(pptponly && rp->bp->htype != 0)
343 		return;
344 
345 	ipifcs = readipifc(net, ipifcs, -1);
346 	if(validip(rp->giaddr))
347 		ipmove(relip, rp->giaddr);
348 	else if(validip(rp->up->raddr))
349 		ipmove(relip, rp->up->raddr);
350 	else
351 		ipmove(relip, rp->up->laddr);
352 	if(rp->e < (uchar*)rp->bp->sname){
353 		warning(0, "packet too short");
354 		return;
355 	}
356 	if(rp->bp->op != Bootrequest){
357 		warning(0, "not bootrequest");
358 		return;
359 	}
360 
361 	if(rp->e >= rp->bp->optdata){
362 		if(memcmp(rp->bp->optmagic, plan9opt, sizeof(rp->bp->optmagic)) == 0)
363 			rp->p9request = 1;
364 		if(memcmp(rp->bp->optmagic, genericopt, sizeof(rp->bp->optmagic)) == 0) {
365 			rp->genrequest = 1;
366 			parseoptions(rp);
367 		}
368 	}
369 	rp->p = rp->bp->optdata;
370 
371 	/*  If no id is specified, make one from the hardware address
372 	 *  of the target.  We assume all zeros is not a hardware address
373 	 *  which could be a mistake.
374 	 */
375 	if(rp->id == nil){
376 		if(rp->bp->hlen > Maxhwlen){
377 			warning(0, "hlen %d", rp->bp->hlen);
378 			return;
379 		}
380 		if(memcmp(zeros, rp->bp->chaddr, rp->bp->hlen) == 0){
381 			warning(0, "no chaddr");
382 			return;
383 		}
384 		sprint(buf, "hwa%2.2ux_", rp->bp->htype);
385 		rp->id = tohex(buf, rp->bp->chaddr, rp->bp->hlen);
386 	}
387 
388 	/* info about gateway */
389 	if(lookupip(relip, &rp->gii, 1) < 0){
390 		warning(0, "lookupip failed");
391 		return;
392 	}
393 
394 	/* info about target system */
395 	if(lookup(rp->bp, &rp->ii, &rp->gii) == 0)
396 		if(rp->ii.indb && rp->ii.dhcpgroup[0] == 0)
397 			rp->staticbinding = 1;
398 
399 	if(rp->dhcptype)
400 		dhcp(rp);
401 	else
402 		bootp(rp);
403 timestamp("done");
404 }
405 
406 static void
407 slowdelay(Req *rp)
408 {
409 	if(slowstat && rp->staticbinding || slowdyn && !rp->staticbinding)
410 		sleep(2000);
411 }
412 
413 void
414 dhcp(Req *rp)
415 {
416 	logdhcp(rp);
417 
418 	switch(rp->dhcptype){
419 	case Discover:
420 		slowdelay(rp);
421 		rcvdiscover(rp);
422 		break;
423 	case Request:
424 		rcvrequest(rp);
425 		break;
426 	case Decline:
427 		rcvdecline(rp);
428 		break;
429 	case Release:
430 		rcvrelease(rp);
431 		break;
432 	case Inform:
433 		rcvinform(rp);
434 		break;
435 	}
436 }
437 
438 void
439 rcvdiscover(Req *rp)
440 {
441 	Binding *b, *nb;
442 
443 	if(rp->staticbinding){
444 		sendoffer(rp, rp->ii.ipaddr, (staticlease > minlease? staticlease: minlease));
445 		return;
446 	}
447 
448 	/*
449 	 *  first look for an outstanding offer
450 	 */
451 	b = idtooffer(rp->id, &rp->gii);
452 
453 	/*
454 	 * rfc2131 says:
455 	 *   If an address is available, the new address
456 	 *   SHOULD be chosen as follows:
457 	 *
458 	 *      o The client's current address as recorded in the client's current
459 	 *        binding, ELSE
460 	 *
461 	 *      o The client's previous address as recorded in the client's (now
462 	 *        expired or released) binding, if that address is in the server's
463 	 *        pool of available addresses and not already allocated, ELSE
464 	 *
465 	 *      o The address requested in the 'Requested IP Address' option, if that
466 	 *        address is valid and not already allocated, ELSE
467 	 *
468 	 *      o A new address allocated from the server's pool of available
469 	 *        addresses; the address is selected based on the subnet from which
470 	 *        the message was received (if 'giaddr' is 0) or on the address of
471 	 *        the relay agent that forwarded the message ('giaddr' when not 0).
472 	 */
473 	if(b == nil){
474 		b = idtobinding(rp->id, &rp->gii, 1);
475 		if(b && b->boundto && strcmp(b->boundto, rp->id) != 0)
476 		if(validip(rp->ip) && samenet(rp->ip, &rp->gii)){
477 			nb = iptobinding(rp->ip, 0);
478 			if(nb && nb->lease < now)
479 				b = nb;
480 		}
481 	}
482 	if(b == nil){
483 		warning(0, "!Discover(%s via %I): no binding %I",
484 			rp->id, rp->gii.ipaddr, rp->ip);
485 		return;
486 	}
487 	mkoffer(b, rp->id, rp->leasetime);
488 	sendoffer(rp, b->ip, b->offer);
489 }
490 
491 void
492 rcvrequest(Req *rp)
493 {
494 	Binding *b;
495 
496 	if(validip(rp->server)){
497 		/* this is a reply to an offer - SELECTING */
498 
499 		/* check for hard assignment */
500 		if(rp->staticbinding){
501 			if(forme(rp->server))
502 				sendack(rp, rp->ii.ipaddr,
503 					(staticlease > minlease? staticlease:
504 					minlease), 1);
505 			else
506 				warning(0, "!Request(%s via %I): for server %I not me",
507 					rp->id, rp->gii.ipaddr, rp->server);
508 			return;
509 		}
510 
511 		b = idtooffer(rp->id, &rp->gii);
512 
513 		/* if we don't have an offer, nak */
514 		if(b == nil){
515 			warning(0, "!Request(%s via %I): no offer",
516 				rp->id, rp->gii.ipaddr);
517 			if(forme(rp->server))
518 				sendnak(rp, "no offer for you");
519 			return;
520 		}
521 
522 		/* if not for me, retract offer */
523 		if(!forme(rp->server)){
524 			b->expoffer = 0;
525 			warning(0, "!Request(%s via %I): for server %I not me",
526 				rp->id, rp->gii.ipaddr, rp->server);
527 			return;
528 		}
529 
530 		/*
531 		 *  if the client is confused about what we offered, nak.
532 		 *  client really shouldn't be specifying this when selecting
533 		 */
534 		if(validip(rp->ip) && ipcmp(rp->ip, b->ip) != 0){
535 			warning(0, "!Request(%s via %I): requests %I, not %I",
536 				rp->id, rp->gii.ipaddr, rp->ip, b->ip);
537 			sendnak(rp, "bad ip address option");
538 			return;
539 		}
540 		if(commitbinding(b) < 0){
541 			warning(0, "!Request(%s via %I): can't commit %I",
542 				rp->id, rp->gii.ipaddr, b->ip);
543 			sendnak(rp, "can't commit binding");
544 			return;
545 		}
546 		sendack(rp, b->ip, b->offer, 1);
547 	} else if(validip(rp->ip)){
548 		/*
549 		 *  checking address/net - INIT-REBOOT
550 		 *
551 		 *  This is a rebooting client that remembers its old
552 		 *  address.
553 		 */
554 		/* check for hard assignment */
555 		if(rp->staticbinding){
556 			if(memcmp(rp->ip, rp->ii.ipaddr, IPaddrlen) != 0){
557 				warning(0, "!Request(%s via %I): %I not valid for %E",
558 					rp->id, rp->gii.ipaddr, rp->ip, rp->bp->chaddr);
559 				sendnak(rp, "not valid");
560 			}
561 			sendack(rp, rp->ii.ipaddr, (staticlease > minlease?
562 				staticlease: minlease), 1);
563 			return;
564 		}
565 
566 		/* make sure the network makes sense */
567 		if(!samenet(rp->ip, &rp->gii)){
568 			warning(0, "!Request(%s via %I): bad forward of %I",
569 				rp->id, rp->gii.ipaddr, rp->ip);
570 			sendnak(rp, "wrong network");
571 			return;
572 		}
573 		b = iptobinding(rp->ip, 0);
574 		if(b == nil){
575 			warning(0, "!Request(%s via %I): no binding for %I",
576 				rp->id, rp->gii.ipaddr, rp->ip);
577 			return;
578 		}
579 		if(memcmp(rp->ip, b->ip, IPaddrlen) != 0 || now > b->lease){
580 			warning(0, "!Request(%s via %I): %I not valid",
581 				rp->id, rp->gii.ipaddr, rp->ip);
582 			sendnak(rp, "not valid");
583 			return;
584 		}
585 		b->offer = b->lease - now;
586 		sendack(rp, b->ip, b->offer, 1);
587 	} else if(validip(rp->ciaddr)){
588 		/*
589 		 *  checking address - RENEWING or REBINDING
590 		 *
591 		 *  these states are indistinguishable in our action.  The only
592 		 *  difference is how close to lease expiration the client is.
593 		 *  If it is really close, it broadcasts the request hoping that
594 		 *  some server will answer.
595 		 */
596 
597 		/* check for hard assignment */
598 		if(rp->staticbinding){
599 			if(ipcmp(rp->ciaddr, rp->ii.ipaddr) != 0){
600 				warning(0, "!Request(%s via %I): %I not valid",
601 					rp->id, rp->gii.ipaddr, rp->ciaddr);
602 				sendnak(rp, "not valid");
603 			}
604 			sendack(rp, rp->ii.ipaddr, (staticlease > minlease?
605 				staticlease: minlease), 1);
606 			return;
607 		}
608 
609 		/* make sure the network makes sense */
610 		if(!samenet(rp->ciaddr, &rp->gii)){
611 			warning(0, "!Request(%s via %I): bad forward of %I",
612 				rp->id, rp->gii.ipaddr, rp->ip);
613 			sendnak(rp, "wrong network");
614 			return;
615 		}
616 		b = iptobinding(rp->ciaddr, 0);
617 		if(b == nil){
618 			warning(0, "!Request(%s via %I): no binding for %I",
619 				rp->id, rp->gii.ipaddr, rp->ciaddr);
620 			return;
621 		}
622 		if(ipcmp(rp->ciaddr, b->ip) != 0){
623 			warning(0, "!Request(%I via %s): %I not valid",
624 				rp->id, rp->gii.ipaddr, rp->ciaddr);
625 			sendnak(rp, "invalid ip address");
626 			return;
627 		}
628 		mkoffer(b, rp->id, rp->leasetime);
629 		if(commitbinding(b) < 0){
630 			warning(0, "!Request(%s via %I): can't commit %I",
631 				rp->id, rp->gii.ipaddr, b->ip);
632 			sendnak(rp, "can't commit binding");
633 			return;
634 		}
635 		sendack(rp, b->ip, b->offer, 1);
636 	}
637 }
638 
639 void
640 rcvdecline(Req *rp)
641 {
642 	Binding *b;
643 	char buf[64];
644 
645 	if(rp->staticbinding)
646 		return;
647 
648 	b = idtooffer(rp->id, &rp->gii);
649 	if(b == nil){
650 		warning(0, "!Decline(%s via %I): no binding",
651 			rp->id, rp->gii.ipaddr);
652 		return;
653 	}
654 
655 	/* mark ip address as in use */
656 	snprint(buf, sizeof(buf), "declined by %s", rp->id);
657 	mkoffer(b, buf, 0x7fffffff);
658 	commitbinding(b);
659 }
660 
661 void
662 rcvrelease(Req *rp)
663 {
664 	Binding *b;
665 
666 	if(rp->staticbinding)
667 		return;
668 
669 	b = idtobinding(rp->id, &rp->gii, 0);
670 	if(b == nil){
671 		warning(0, "!Release(%s via %I): no binding",
672 			rp->id, rp->gii.ipaddr);
673 		return;
674 	}
675 	if(strcmp(rp->id, b->boundto) != 0){
676 		warning(0, "!Release(%s via %I): invalid release of %I",
677 			rp->id, rp->gii.ipaddr, rp->ip);
678 		return;
679 	}
680 	warning(0, "Release(%s via %I): releasing %I", b->boundto, rp->gii.ipaddr, b->ip);
681 	if(releasebinding(b, rp->id) < 0)
682 		warning(0, "release: couldn't release");
683 }
684 
685 void
686 rcvinform(Req *rp)
687 {
688 	Binding *b;
689 
690 	if(rp->staticbinding){
691 		sendack(rp, rp->ii.ipaddr, 0, 0);
692 		return;
693 	}
694 
695 	b = iptobinding(rp->ciaddr, 0);
696 	if(b == nil){
697 		warning(0, "!Inform(%s via %I): no binding for %I",
698 			rp->id, rp->gii.ipaddr, rp->ip);
699 		return;
700 	}
701 	sendack(rp, b->ip, 0, 0);
702 }
703 
704 int
705 setsiaddr(uchar *siaddr, uchar *saddr, uchar *laddr)
706 {
707 	if(ipcmp(saddr, IPnoaddr) != 0){
708 		v6tov4(siaddr, saddr);
709 		return 0;
710 	} else {
711 		v6tov4(siaddr, laddr);
712 		return 1;
713 	}
714 }
715 
716 int
717 ismuted(Req *rp)
718 {
719 	return mute || (mutestat && rp->staticbinding);
720 }
721 
722 void
723 sendoffer(Req *rp, uchar *ip, int offer)
724 {
725 	int n;
726 	ushort flags;
727 	Bootp *bp;
728 	Udphdr *up;
729 
730 	bp = rp->bp;
731 	up = rp->up;
732 
733 	/*
734 	 *  set destination
735 	 */
736 	flags = nhgets(bp->flags);
737 	if(validip(rp->giaddr)){
738 		ipmove(up->raddr, rp->giaddr);
739 		hnputs(up->rport, 67);
740 	} else if(flags & Fbroadcast){
741 		ipmove(up->raddr, IPv4bcast);
742 		hnputs(up->rport, 68);
743 	} else {
744 		ipmove(up->raddr, ip);
745 		if(bp->htype == 1)
746 			arpenter(up->raddr, bp->chaddr);
747 		hnputs(up->rport, 68);
748 	}
749 
750 	/*
751 	 *  fill in standard bootp part
752 	 */
753 	bp->op = Bootreply;
754 	bp->hops = 0;
755 	hnputs(bp->secs, 0);
756 	memset(bp->ciaddr, 0, sizeof(bp->ciaddr));
757 	v6tov4(bp->giaddr, rp->giaddr);
758 	v6tov4(bp->yiaddr, ip);
759 	setsiaddr(bp->siaddr, rp->ii.tftp, up->laddr);
760 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
761 	strncpy(bp->file, rp->ii.bootf, sizeof(bp->file));
762 
763 	/*
764 	 *  set options
765 	 */
766 	byteopt(rp, ODtype, Offer);
767 	longopt(rp, ODlease, offer);
768 	addropt(rp, ODserverid, up->laddr);
769 	miscoptions(rp, ip);
770 	termopt(rp);
771 
772 	logdhcpout(rp, "Offer");
773 
774 	/*
775 	 *  send
776 	 */
777 	n = rp->p - rp->buf;
778 	if(!ismuted(rp) && write(rp->fd, rp->buf, n) != n)
779 		warning(0, "offer: write failed: %r");
780 }
781 
782 void
783 sendack(Req *rp, uchar *ip, int offer, int sendlease)
784 {
785 	int n;
786 	ushort flags;
787 	Bootp *bp;
788 	Udphdr *up;
789 
790 	bp = rp->bp;
791 	up = rp->up;
792 
793 	/*
794 	 *  set destination
795 	 */
796 	flags = nhgets(bp->flags);
797 	if(validip(rp->giaddr)){
798 		ipmove(up->raddr, rp->giaddr);
799 		hnputs(up->rport, 67);
800 	} else if(flags & Fbroadcast){
801 		ipmove(up->raddr, IPv4bcast);
802 		hnputs(up->rport, 68);
803 	} else {
804 		ipmove(up->raddr, ip);
805 		if(bp->htype == 1)
806 			arpenter(up->raddr, bp->chaddr);
807 		hnputs(up->rport, 68);
808 	}
809 
810 	/*
811 	 *  fill in standard bootp part
812 	 */
813 	bp->op = Bootreply;
814 	bp->hops = 0;
815 	hnputs(bp->secs, 0);
816 	v6tov4(bp->giaddr, rp->giaddr);
817 	v6tov4(bp->yiaddr, ip);
818 	setsiaddr(bp->siaddr, rp->ii.tftp, up->laddr);
819 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
820 	strncpy(bp->file, rp->ii.bootf, sizeof(bp->file));
821 
822 	/*
823 	 *  set options
824 	 */
825 	byteopt(rp, ODtype, Ack);
826 	if(sendlease){
827 		longopt(rp, ODlease, offer);
828 	}
829 	addropt(rp, ODserverid, up->laddr);
830 	miscoptions(rp, ip);
831 	termopt(rp);
832 
833 	logdhcpout(rp, "Ack");
834 
835 	/*
836 	 *  send
837 	 */
838 	n = rp->p - rp->buf;
839 	if(!ismuted(rp) && write(rp->fd, rp->buf, n) != n)
840 		warning(0, "ack: write failed: %r");
841 }
842 
843 void
844 sendnak(Req *rp, char *msg)
845 {
846 	int n;
847 	Bootp *bp;
848 	Udphdr *up;
849 
850 	bp = rp->bp;
851 	up = rp->up;
852 
853 	/*
854 	 *  set destination (always broadcast)
855 	 */
856 	if(validip(rp->giaddr)){
857 		ipmove(up->raddr, rp->giaddr);
858 		hnputs(up->rport, 67);
859 	} else {
860 		ipmove(up->raddr, IPv4bcast);
861 		hnputs(up->rport, 68);
862 	}
863 
864 	/*
865 	 *  fill in standard bootp part
866 	 */
867 	bp->op = Bootreply;
868 	bp->hops = 0;
869 	hnputs(bp->secs, 0);
870 	v6tov4(bp->giaddr, rp->giaddr);
871 	memset(bp->ciaddr, 0, sizeof(bp->ciaddr));
872 	memset(bp->yiaddr, 0, sizeof(bp->yiaddr));
873 	memset(bp->siaddr, 0, sizeof(bp->siaddr));
874 
875 	/*
876 	 *  set options
877 	 */
878 	byteopt(rp, ODtype, Nak);
879 	addropt(rp, ODserverid, up->laddr);
880 	if(msg)
881 		stringopt(rp, ODmessage, msg);
882 	if(strncmp(rp->id, "id", 2) == 0)
883 		hexopt(rp, ODclientid, rp->id+2);
884 	termopt(rp);
885 
886 	logdhcpout(rp, "Nak");
887 
888 	/*
889 	 *  send nak
890 	 */
891 	n = rp->p - rp->buf;
892 	if(!ismuted(rp) && write(rp->fd, rp->buf, n) != n)
893 		warning(0, "nak: write failed: %r");
894 }
895 
896 void
897 bootp(Req *rp)
898 {
899 	int n;
900 	Bootp *bp;
901 	Udphdr *up;
902 	ushort flags;
903 	Iplifc *lifc;
904 	Info *iip;
905 
906 	warning(0, "bootp %s %I->%I from %s via %I, file %s",
907 		rp->genrequest? "generic": (rp->p9request? "p9": ""),
908 		rp->up->raddr, rp->up->laddr,
909 		rp->id, rp->gii.ipaddr,
910 		rp->bp->file);
911 
912 	if(nobootp)
913 		return;
914 
915 	bp = rp->bp;
916 	up = rp->up;
917 	iip = &rp->ii;
918 
919 	if(rp->staticbinding == 0){
920 		warning(0, "bootp from unknown %s via %I", rp->id, rp->gii.ipaddr);
921 		return;
922 	}
923 
924 	/* ignore if not for us */
925 	if(*bp->sname){
926 		if(strcmp(bp->sname, mysysname) != 0){
927 			bp->sname[20] = 0;
928 			warning(0, "bootp for server %s", bp->sname);
929 			return;
930 		}
931 	} else
932 		slowdelay(rp);
933 
934 	/* ignore if we don't know what file to load */
935 	if(*bp->file == 0){
936 		if(rp->genrequest && *iip->bootf2) /* if not plan 9 & have alternate file... */
937 			strncpy(bp->file, iip->bootf2, sizeof(bp->file));
938 		else if(*iip->bootf)
939 			strncpy(bp->file, iip->bootf, sizeof(bp->file));
940 		else if(*bp->sname) /* if we were asked, respond no matter what */
941 			bp->file[0] = '\0';
942 		else {
943 			warning(0, "no bootfile for %I", iip->ipaddr);
944 			return;
945 		}
946 	}
947 
948 	/* ignore if the file is unreadable */
949 	if((!rp->genrequest) && bp->file[0] && access(bp->file, 4) < 0){
950 		warning(0, "inaccessible bootfile1 %s", bp->file);
951 		return;
952 	}
953 
954 	bp->op = Bootreply;
955 	v6tov4(bp->yiaddr, iip->ipaddr);
956 	if(rp->p9request){
957 		warning(0, "p9bootp: %I", iip->ipaddr);
958 		memmove(bp->optmagic, plan9opt, 4);
959 		if(iip->gwip == 0)
960 			v4tov6(iip->gwip, bp->giaddr);
961 		rp->p += sprint((char*)rp->p, "%V %I %I %I", iip->ipmask+IPv4off, iip->fsip,
962 				iip->auip, iip->gwip);
963 		sprint(optbuf, "%s", (char*)(bp->optmagic));
964 	} else if(rp->genrequest){
965 		warning(0, "genericbootp: %I", iip->ipaddr);
966 		memmove(bp->optmagic, genericopt, 4);
967 		miscoptions(rp, iip->ipaddr);
968 		termopt(rp);
969 	} else if(iip->vendor[0] != 0) {
970 		warning(0, "bootp vendor field: %s", iip->vendor);
971 		memset(rp->p, 0, 128-4);
972 		rp->p += sprint((char*)bp->optmagic, "%s", iip->vendor);
973 	} else {
974 		memset(rp->p, 0, 128-4);
975 		rp->p += 128-4;
976 	}
977 
978 	/*
979 	 *  set destination
980 	 */
981 	flags = nhgets(bp->flags);
982 	if(validip(rp->giaddr)){
983 		ipmove(up->raddr, rp->giaddr);
984 		hnputs(up->rport, 67);
985 	} else if(flags & Fbroadcast){
986 		ipmove(up->raddr, IPv4bcast);
987 		hnputs(up->rport, 68);
988 	} else {
989 		v4tov6(up->raddr, bp->yiaddr);
990 		if(bp->htype == 1)
991 			arpenter(up->raddr, bp->chaddr);
992 		hnputs(up->rport, 68);
993 	}
994 
995 	/*
996 	 *  select best local address if destination is directly connected
997 	 */
998 	lifc = findlifc(up->raddr);
999 	if(lifc)
1000 		ipmove(up->laddr, lifc->ip);
1001 
1002 	/*
1003 	 *  our identity
1004 	 */
1005 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
1006 
1007 	/*
1008 	 *  set tftp server
1009 	 */
1010 	setsiaddr(bp->siaddr, iip->tftp, up->laddr);
1011 	if(rp->genrequest && *iip->bootf2)
1012 		setsiaddr(bp->siaddr, iip->tftp2, up->laddr);
1013 
1014 	/*
1015 	 * RFC 1048 says that we must pad vendor field with
1016 	 * zeros until we have a 64 byte field.
1017 	 */
1018 	n = rp->p - rp->bp->optdata;
1019 	if(n < 64-4) {
1020 		memset(rp->p, 0, (64-4)-n);
1021 		rp->p += (64-4)-n;
1022 	}
1023 
1024 	/*
1025 	 *  send
1026 	 */
1027 	n = rp->p - rp->buf;
1028 	if(!ismuted(rp) && write(rp->fd, rp->buf, n) != n)
1029 		warning(0, "bootp: write failed: %r");
1030 
1031 	warning(0, "bootp via %I: file %s xid(%ux)flag(%ux)ci(%V)gi(%V)yi(%V)si(%V) %s",
1032 			up->raddr, bp->file, nhgetl(bp->xid), nhgets(bp->flags),
1033 			bp->ciaddr, bp->giaddr, bp->yiaddr, bp->siaddr,
1034 			optbuf);
1035 }
1036 
1037 void
1038 parseoptions(Req *rp)
1039 {
1040 	int n, c, code;
1041 	uchar *o, *p;
1042 
1043 	p = rp->p;
1044 
1045 	while(p < rp->e){
1046 		code = *p++;
1047 		if(code == 255)
1048 			break;
1049 		if(code == 0)
1050 			continue;
1051 
1052 		/* ignore anything that's too long */
1053 		n = *p++;
1054 		o = p;
1055 		p += n;
1056 		if(p > rp->e)
1057 			return;
1058 
1059 		switch(code){
1060 		case ODipaddr:	/* requested ip address */
1061 			if(n == IPv4addrlen)
1062 				v4tov6(rp->ip, o);
1063 			break;
1064 		case ODlease:	/* requested lease time */
1065 			rp->leasetime = nhgetl(o);
1066 			if(rp->leasetime > MaxLease || rp->leasetime < 0)
1067 				rp->leasetime = MaxLease;
1068 			break;
1069 		case ODtype:
1070 			c = *o;
1071 			if(c < 10 && c > 0)
1072 				rp->dhcptype = c;
1073 			break;
1074 		case ODserverid:
1075 			if(n == IPv4addrlen)
1076 				v4tov6(rp->server, o);
1077 			break;
1078 		case ODmessage:
1079 			if(n > sizeof rp->msg-1)
1080 				n = sizeof rp->msg-1;
1081 			memmove(rp->msg, o, n);
1082 			rp->msg[n] = 0;
1083 			break;
1084 		case ODmaxmsg:
1085 			c = nhgets(o);
1086 			c -= 28;
1087 			c += Udphdrsize;
1088 			if(c > 0)
1089 				rp->max = rp->buf + c;
1090 			break;
1091 		case ODclientid:
1092 			if(n <= 1)
1093 				break;
1094 			rp->id = toid( o, n);
1095 			break;
1096 		case ODparams:
1097 			if(n > sizeof(rp->requested))
1098 				n = sizeof(rp->requested);
1099 			memmove(rp->requested, o, n);
1100 			break;
1101 		case ODvendorclass:
1102 			if(n >= sizeof(rp->vendorclass))
1103 				n = sizeof(rp->vendorclass)-1;
1104 			memmove(rp->vendorclass, o, n);
1105 			rp->vendorclass[n] = 0;
1106 			if(strncmp((char*)rp->vendorclass, "p9-", 3) == 0)
1107 				strcpy(rp->cputype, (char*)rp->vendorclass+3);
1108 			break;
1109 		case OBend:
1110 			return;
1111 		}
1112 	}
1113 }
1114 
1115 void
1116 remrequested(Req *rp, int opt)
1117 {
1118 	uchar *p;
1119 
1120 	p = memchr(rp->requested, opt, sizeof(rp->requested));
1121 	if(p != nil)
1122 		*p = OBpad;
1123 }
1124 
1125 void
1126 miscoptions(Req *rp, uchar *ip)
1127 {
1128 	int i, j, na;
1129 	uchar x[2*IPaddrlen], vopts[Maxoptlen];
1130 	uchar *op, *omax;
1131 	uchar *addrs[2];
1132 	char *p;
1133 	char *attr[100], **a;
1134 	Ndbtuple *t;
1135 
1136 	addrs[0] = x;
1137 	addrs[1] = x+IPaddrlen;
1138 
1139 	/* always supply these */
1140 	maskopt(rp, OBmask, rp->gii.ipmask);
1141 	if(validip(rp->gii.gwip)){
1142 		remrequested(rp, OBrouter);
1143 		addropt(rp, OBrouter, rp->gii.gwip);
1144 	} else if(validip(rp->giaddr)){
1145 		remrequested(rp, OBrouter);
1146 		addropt(rp, OBrouter, rp->giaddr);
1147 	}
1148 
1149 	/*
1150 	 * OBhostname for the HP4000M switches
1151 	 * (this causes NT to log infinite errors - tough shit)
1152 	 */
1153 	if(*rp->ii.domain){
1154 		remrequested(rp, OBhostname);
1155 		stringopt(rp, OBhostname, rp->ii.domain);
1156 	}
1157 	if(*rp->ii.rootpath)
1158 		stringopt(rp, OBrootpath, rp->ii.rootpath);
1159 
1160 	/* figure out what we need to lookup */
1161 	na = 0;
1162 	a = attr;
1163 	if(*rp->ii.domain == 0)
1164 		a[na++] = "dom";
1165 	for(i = 0; i < sizeof(rp->requested); i++)
1166 		switch(rp->requested[i]){
1167 		case OBrouter:
1168 			a[na++] = "@ipgw";
1169 			break;
1170 		case OBdnserver:
1171 			a[na++] = "@dns";
1172 			break;
1173 		case OBnetbiosns:
1174 			a[na++] = "@wins";
1175 			break;
1176 		case OBsmtpserver:
1177 			a[na++] = "@smtp";
1178 			break;
1179 		case OBpop3server:
1180 			a[na++] = "@pop3";
1181 			break;
1182 		case OBwwwserver:
1183 			a[na++] = "@www";
1184 			break;
1185 		case OBntpserver:
1186 			a[na++] = "@ntp";
1187 			break;
1188 		case OBtimeserver:
1189 			a[na++] = "@time";
1190 			break;
1191 		}
1192 	if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0
1193 	|| strncmp((char*)rp->vendorclass, "p9-", 3) == 0){
1194 		a[na++] = "@fs";
1195 		a[na++] = "@auth";
1196 	}
1197 	t = lookupinfo(ip, a, na);
1198 
1199 	/* lookup anything we might be missing */
1200 	if(*rp->ii.domain == 0)
1201 		lookupname(rp->ii.domain, t);
1202 
1203 	/* add any requested ones that we know about */
1204 	for(i = 0; i < sizeof(rp->requested); i++)
1205 		switch(rp->requested[i]){
1206 		case OBrouter:
1207 			j = lookupserver("ipgw", addrs, t);
1208 			addrsopt(rp, OBrouter, addrs, j);
1209 			break;
1210 		case OBdnserver:
1211 			j = lookupserver("dns", addrs, t);
1212 			addrsopt(rp, OBdnserver, addrs, j);
1213 			break;
1214 		case OBhostname:
1215 			if(*rp->ii.domain)
1216 				stringopt(rp, OBhostname, rp->ii.domain);
1217 			break;
1218 		case OBdomainname:
1219 			p = strchr(rp->ii.domain, '.');
1220 			if(p)
1221 				stringopt(rp, OBdomainname, p+1);
1222 			break;
1223 		case OBnetbiosns:
1224 			j = lookupserver("wins", addrs, t);
1225 			addrsopt(rp, OBnetbiosns, addrs, j);
1226 			break;
1227 		case OBnetbiostype:
1228 			/* p-node: peer to peer WINS queries */
1229 			byteopt(rp, OBnetbiostype, 0x2);
1230 			break;
1231 		case OBsmtpserver:
1232 			j = lookupserver("smtp", addrs, t);
1233 			addrsopt(rp, OBsmtpserver, addrs, j);
1234 			break;
1235 		case OBpop3server:
1236 			j = lookupserver("pop3", addrs, t);
1237 			addrsopt(rp, OBpop3server, addrs, j);
1238 			break;
1239 		case OBwwwserver:
1240 			j = lookupserver("www", addrs, t);
1241 			addrsopt(rp, OBwwwserver, addrs, j);
1242 			break;
1243 		case OBntpserver:
1244 			j = lookupserver("ntp", addrs, t);
1245 			addrsopt(rp, OBntpserver, addrs, j);
1246 			break;
1247 		case OBtimeserver:
1248 			j = lookupserver("time", addrs, t);
1249 			addrsopt(rp, OBtimeserver, addrs, j);
1250 			break;
1251 		case OBttl:
1252 			byteopt(rp, OBttl, 255);
1253 			break;
1254 		}
1255 
1256 	/* add plan9 specific options */
1257 	if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0
1258 	|| strncmp((char*)rp->vendorclass, "p9-", 3) == 0){
1259 		/* point to temporary area */
1260 		op = rp->p;
1261 		omax = rp->max;
1262 		/* stash encoded options in vopts */
1263 		rp->p = vopts;
1264 		rp->max = vopts + sizeof(vopts) - 1;
1265 
1266 		/* emit old v4 addresses first to make sure that they fit */
1267 		addrsopt(rp, OP9fsv4, addrs, lookupserver("fs", addrs, t));
1268 		addrsopt(rp, OP9authv4, addrs, lookupserver("auth", addrs, t));
1269 
1270 		p9addrsopt(rp, OP9fs, addrs, lookupserver("fs", addrs, t));
1271 		p9addrsopt(rp, OP9auth, addrs, lookupserver("auth", addrs, t));
1272 		p9addrsopt(rp, OP9ipaddr, addrs, lookupserver("ip", addrs, t));
1273 		p9addrsopt(rp, OP9ipmask, addrs, lookupserver("ipmask", addrs, t));
1274 		p9addrsopt(rp, OP9ipgw, addrs, lookupserver("ipgw", addrs, t));
1275 
1276 		/* point back to packet, encapsulate vopts into packet */
1277 		j = rp->p - vopts;
1278 		rp->p = op;
1279 		rp->max = omax;
1280 		vectoropt(rp, OBvendorinfo, vopts, j);
1281 	}
1282 
1283 	ndbfree(t);
1284 }
1285 
1286 int
1287 openlisten(char *net)
1288 {
1289 	int fd, cfd;
1290 	char data[128], devdir[40];
1291 
1292 	sprint(data, "%s/udp!*!bootp", net);
1293 	cfd = announce(data, devdir);
1294 	if(cfd < 0)
1295 		fatal(1, "can't announce");
1296 	if(fprint(cfd, "headers") < 0)
1297 		fatal(1, "can't set header mode");
1298 
1299 	sprint(data, "%s/data", devdir);
1300 	fd = open(data, ORDWR);
1301 	if(fd < 0)
1302 		fatal(1, "open udp data");
1303 	return fd;
1304 }
1305 
1306 void
1307 fatal(int syserr, char *fmt, ...)
1308 {
1309 	char buf[Maxloglen];
1310 	va_list arg;
1311 
1312 	va_start(arg, fmt);
1313 	vseprint(buf, buf+sizeof(buf), fmt, arg);
1314 	va_end(arg);
1315 	if(syserr)
1316 		syslog(1, blog, "%s: %r", buf);
1317 	else
1318 		syslog(1, blog, "%s", buf);
1319 	exits(buf);
1320 }
1321 
1322 void
1323 warning(int syserr, char *fmt, ...)
1324 {
1325 	char buf[Maxloglen];
1326 	va_list arg;
1327 
1328 	va_start(arg, fmt);
1329 	vseprint(buf, buf+sizeof(buf), fmt, arg);
1330 	va_end(arg);
1331 	if(syserr){
1332 		syslog(0, blog, "%s: %r", buf);
1333 		if(debug)
1334 			fprint(2, "%s: %r\n", buf);
1335 	} else {
1336 		syslog(0, blog, "%s", buf);
1337 		if(debug)
1338 			fprint(2, "%s\n", buf);
1339 	}
1340 }
1341 
1342 char*
1343 readsysname(void)
1344 {
1345 	static char name[128];
1346 	char *p;
1347 	int n, fd;
1348 
1349 	fd = open("/dev/sysname", OREAD);
1350 	if(fd >= 0){
1351 		n = read(fd, name, sizeof(name)-1);
1352 		close(fd);
1353 		if(n > 0){
1354 			name[n] = 0;
1355 			return name;
1356 		}
1357 	}
1358 	p = getenv("sysname");
1359 	if(p == nil || *p == 0)
1360 		return "unknown";
1361 	return p;
1362 }
1363 
1364 extern int
1365 validip(uchar *ip)
1366 {
1367 	if(ipcmp(ip, IPnoaddr) == 0)
1368 		return 0;
1369 	if(ipcmp(ip, v4prefix) == 0)
1370 		return 0;
1371 	return 1;
1372 }
1373 
1374 void
1375 longopt(Req *rp, int t, long v)
1376 {
1377 	if(rp->p + 6 > rp->max)
1378 		return;
1379 	*rp->p++ = t;
1380 	*rp->p++ = 4;
1381 	hnputl(rp->p, v);
1382 	rp->p += 4;
1383 
1384 	op = seprint(op, oe, "%s(%ld)", optname[t], v);
1385 }
1386 
1387 void
1388 addropt(Req *rp, int t, uchar *ip)
1389 {
1390 	if(rp->p + 6 > rp->max)
1391 		return;
1392 	if (!isv4(ip)) {
1393 		if (debug)
1394 			warning(0, "not a v4 %s server: %I", optname[t], ip);
1395 		return;
1396 	}
1397 	*rp->p++ = t;
1398 	*rp->p++ = 4;
1399 	memmove(rp->p, ip+IPv4off, 4);
1400 	rp->p += 4;
1401 
1402 	op = seprint(op, oe, "%s(%I)", optname[t], ip);
1403 }
1404 
1405 void
1406 maskopt(Req *rp, int t, uchar *ip)
1407 {
1408 	if(rp->p + 6 > rp->max)
1409 		return;
1410 	*rp->p++ = t;
1411 	*rp->p++ = 4;
1412 	memmove(rp->p, ip+IPv4off, 4);
1413 	rp->p += 4;
1414 
1415 	op = seprint(op, oe, "%s(%M)", optname[t], ip);
1416 }
1417 
1418 void
1419 addrsopt(Req *rp, int t, uchar **ip, int i)
1420 {
1421 	int v4s, n;
1422 
1423 	if(i <= 0)
1424 		return;
1425 	if(rp->p + 2 + 4*i > rp->max)
1426 		return;
1427 	v4s = 0;
1428 	for(n = i; n-- > 0; )
1429 		if (isv4(ip[n]))
1430 			v4s++;
1431 	if (v4s <= 0) {
1432 		if (debug)
1433 			warning(0, "no v4 %s servers", optname[t]);
1434 		return;
1435 	}
1436 	*rp->p++ = t;
1437 	*rp->p++ = 4*v4s;
1438 	op = seprint(op, oe, " %s(", optname[t]);
1439 	while(i-- > 0){
1440 		if (!isv4(*ip)) {
1441 			op = seprint(op, oe, " skipping %I ", *ip);
1442 			continue;
1443 		}
1444 		v6tov4(rp->p, *ip);
1445 		rp->p += 4;
1446 		op = seprint(op, oe, "%I", *ip);
1447 		ip++;
1448 		if(i > 0)
1449 			op = seprint(op, oe, " ");
1450 	}
1451 	op = seprint(op, oe, ")");
1452 }
1453 
1454 void
1455 p9addrsopt(Req *rp, int t, uchar **ip, int i)
1456 {
1457 	char *pkt, *payload;
1458 
1459 	if(i <= 0 || !v6opts)
1460 		return;
1461 	pkt = (char *)rp->p;
1462 	*pkt++ = t;			/* option */
1463 	pkt++;				/* fill in payload length below */
1464 	payload = pkt;
1465 	*pkt++ = i;			/* plan 9 address count */
1466 	op = seprint(op, oe, " %s(", optname[t]);
1467 	while(i-- > 0){
1468 		pkt = seprint(pkt, (char *)rp->max, "%I", *ip);
1469 		if ((uchar *)pkt+1 >= rp->max) {
1470 			op = seprint(op, oe, "<out of mem1>)");
1471 			return;
1472 		}
1473 		pkt++;			/* leave NUL as terminator */
1474 		op = seprint(op, oe, "%I", *ip);
1475 		ip++;
1476 		if(i > 0)
1477 			op = seprint(op, oe, " ");
1478 	}
1479 	if ((uchar *)pkt - rp->p > 0377) {
1480 		op = seprint(op, oe, "<out of mem2>)");
1481 		return;
1482 	}
1483 	op = seprint(op, oe, ")");
1484 	rp->p[1] = pkt - payload;	/* payload length */
1485 	rp->p = (uchar *)pkt;
1486 }
1487 
1488 void
1489 byteopt(Req *rp, int t, uchar v)
1490 {
1491 	if(rp->p + 3 > rp->max)
1492 		return;
1493 	*rp->p++ = t;
1494 	*rp->p++ = 1;
1495 	*rp->p++ = v;
1496 
1497 	op = seprint(op, oe, "%s(%d)", optname[t], v);
1498 }
1499 
1500 void
1501 termopt(Req *rp)
1502 {
1503 	if(rp->p + 1 > rp->max)
1504 		return;
1505 	*rp->p++ = OBend;
1506 }
1507 
1508 void
1509 stringopt(Req *rp, int t, char *str)
1510 {
1511 	int n;
1512 
1513 	n = strlen(str);
1514 	if(n > 255)
1515 		n = 255;
1516 	if(rp->p+n+2 > rp->max)
1517 		return;
1518 	*rp->p++ = t;
1519 	*rp->p++ = n;
1520 	memmove(rp->p, str, n);
1521 	rp->p += n;
1522 
1523 	op = seprint(op, oe, "%s(%s)", optname[t], str);
1524 }
1525 
1526 void
1527 vectoropt(Req *rp, int t, uchar *v, int n)
1528 {
1529 	int i;
1530 
1531 	if(n > 255) {
1532 		n = 255;
1533 		op = seprint(op, oe, "vectoropt len %d > 255 ", n);
1534 	}
1535 	if(rp->p+n+2 > rp->max)
1536 		return;
1537 	*rp->p++ = t;
1538 	*rp->p++ = n;
1539 	memmove(rp->p, v, n);
1540 	rp->p += n;
1541 
1542 	op = seprint(op, oe, "%s(", optname[t]);
1543 	if(n > 0)
1544 		op = seprint(op, oe, "%ud", v[0]);
1545 	for(i = 1; i < n; i++)
1546 		op = seprint(op, oe, " %ud", v[i]);
1547 	op = seprint(op, oe, ")");
1548 }
1549 
1550 int
1551 fromhex(int x)
1552 {
1553 	if(x >= '0' && x <= '9')
1554 		return x - '0';
1555 	return x - 'a';
1556 }
1557 
1558 void
1559 hexopt(Req *rp, int t, char *str)
1560 {
1561 	int n;
1562 
1563 	n = strlen(str);
1564 	n /= 2;
1565 	if(n > 255)
1566 		n = 255;
1567 	if(rp->p+n+2 > rp->max)
1568 		return;
1569 	*rp->p++ = t;
1570 	*rp->p++ = n;
1571 	while(n-- > 0){
1572 		*rp->p++ = (fromhex(str[0])<<4)|fromhex(str[1]);
1573 		str += 2;
1574 	}
1575 
1576 	op = seprint(op, oe, "%s(%s)", optname[t], str);
1577 }
1578 
1579 void
1580 arpenter(uchar *ip, uchar *ether)
1581 {
1582 	int f;
1583 	char buf[256];
1584 
1585 	sprint(buf, "%s/arp", net);
1586 	f = open(buf, OWRITE);
1587 	if(f < 0){
1588 		syslog(debug, blog, "open %s: %r", buf);
1589 		return;
1590 	}
1591 	fprint(f, "add ether %I %E", ip, ether);
1592 	close(f);
1593 }
1594 
1595 char *dhcpmsgname[] =
1596 {
1597 	[Discover]	"Discover",
1598 	[Offer]		"Offer",
1599 	[Request]	"Request",
1600 	[Decline]	"Decline",
1601 	[Ack]		"Ack",
1602 	[Nak]		"Nak",
1603 	[Release]	"Release",
1604 	[Inform]	"Inform",
1605 };
1606 
1607 void
1608 logdhcp(Req *rp)
1609 {
1610 	char buf[4096];
1611 	char *p, *e;
1612 	int i;
1613 
1614 	p = buf;
1615 	e = buf + sizeof(buf);
1616 	if(rp->dhcptype > 0 && rp->dhcptype <= Inform)
1617 		p = seprint(p, e, "%s(", dhcpmsgname[rp->dhcptype]);
1618 	else
1619 		p = seprint(p, e, "%d(", rp->dhcptype);
1620 	p = seprint(p, e, "%I->%I) xid(%ux)flag(%ux)", rp->up->raddr, rp->up->laddr,
1621 		nhgetl(rp->bp->xid), nhgets(rp->bp->flags));
1622 	if(rp->bp->htype == 1)
1623 		p = seprint(p, e, "ea(%E)", rp->bp->chaddr);
1624 	if(validip(rp->ciaddr))
1625 		p = seprint(p, e, "ci(%I)", rp->ciaddr);
1626 	if(validip(rp->giaddr))
1627 		p = seprint(p, e, "gi(%I)", rp->giaddr);
1628 	if(validip(rp->ip))
1629 		p = seprint(p, e, "ip(%I)", rp->ip);
1630 	if(rp->id != nil)
1631 		p = seprint(p, e, "id(%s)", rp->id);
1632 	if(rp->leasetime)
1633 		p = seprint(p, e, "leas(%d)", rp->leasetime);
1634 	if(validip(rp->server))
1635 		p = seprint(p, e, "sid(%I)", rp->server);
1636 	p = seprint(p, e, "need(");
1637 	for(i = 0; i < sizeof(rp->requested); i++)
1638 		if(rp->requested[i] != 0)
1639 			p = seprint(p, e, "%s ", optname[rp->requested[i]]);
1640 	p = seprint(p, e, ")");
1641 
1642 	USED(p);
1643 	syslog(0, blog, "%s", buf);
1644 }
1645 
1646 void
1647 logdhcpout(Req *rp, char *type)
1648 {
1649 	syslog(0, blog, "%s(%I-%I)id(%s)ci(%V)gi(%V)yi(%V)si(%V) %s",
1650 		type, rp->up->laddr, rp->up->raddr, rp->id,
1651 		rp->bp->ciaddr, rp->bp->giaddr, rp->bp->yiaddr, rp->bp->siaddr, optbuf);
1652 }
1653 
1654 /*
1655  *  if we get behind, it's useless to try answering since the sender
1656  *  will probably have retransmitted with a differnt sequence number.
1657  *  So dump all but the last message in the queue.
1658  */
1659 void
1660 ding(void*, char *msg)
1661 {
1662 	if(strstr(msg, "alarm"))
1663 		noted(NCONT);
1664 	else
1665 		noted(NDFLT);
1666 }
1667 
1668 int
1669 readlast(int fd, uchar *buf, int len)
1670 {
1671 	int lastn, n;
1672 
1673 	notify(ding);
1674 
1675 	lastn = 0;
1676 	for(;;){
1677 		alarm(20);
1678 		n = read(fd, buf, len);
1679 		alarm(0);
1680 		if(n < 0){
1681 			if(lastn > 0)
1682 				return lastn;
1683 			break;
1684 		}
1685 		lastn = n;
1686 	}
1687 	return read(fd, buf, len);
1688 }
1689