xref: /plan9/sys/src/cmd/ip/dhcpd/dhcpd.c (revision 282e677fa45fb578cdb8bc2c412ac084c367776e)
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 typedef struct Req Req;
13 struct Req
14 {
15 	int	fd;			/* for reply */
16 	Bootp	*bp;
17 	OUdphdr	*up;
18 	uchar	*e;			/* end of received message */
19 	uchar	*p;			/* options pointer */
20 	uchar	*max;			/* max end of reply */
21 
22 	/* expanded to v6 */
23 	uchar	ciaddr[IPaddrlen];
24 	uchar	giaddr[IPaddrlen];
25 
26 	/* parsed options */
27 	int	p9request;		/* true if this is a bootp with plan9 options */
28 	int	genrequest;		/* true if this is a bootp with generic options */
29 	int	dhcptype;		/* dhcp message type */
30 	int	leasetime;		/* dhcp lease */
31 	uchar	ip[IPaddrlen];		/* requested address */
32 	uchar	server[IPaddrlen];	/* server address */
33 	char	msg[ERRMAX];		/* error message */
34 	char	vci[32];		/* vendor class id */
35 	char	*id;			/* client id */
36 	uchar	requested[32];		/* requested params */
37 	uchar	vendorclass[32];
38 	char	cputype[32-3];
39 
40 	Info	gii;			/* about target network */
41 	Info	ii;			/* about target system */
42 	int	staticbinding;
43 
44 	uchar buf[2*1024];		/* message buffer */
45 };
46 
47 #define TFTP "/lib/tftpd"
48 char	*blog = "ipboot";
49 char	mysysname[64];
50 Ipifc	*ipifcs;
51 int	debug;
52 int	nobootp;
53 long	now;
54 int	slow;
55 char	net[256];
56 
57 int	pptponly;	// only answer request that came from the pptp server
58 int	mute;
59 int	minlease = MinLease;
60 
61 ulong	start;
62 
63 /* option magic */
64 char plan9opt[4] = { 'p', '9', ' ', ' ' };
65 char genericopt[4] = { 0x63, 0x82, 0x53, 0x63 };
66 
67 /* well known addresses */
68 uchar zeros[Maxhwlen];
69 
70 /* option debug buffer */
71 char optbuf[1024];
72 char *op;
73 char *oe = optbuf + sizeof(optbuf);
74 
75 char *optname[256] =
76 {
77 [OBend]			"end",
78 [OBpad]			"pad",
79 [OBmask]		"mask",
80 [OBtimeoff]		"timeoff",
81 [OBrouter]		"router",
82 [OBtimeserver]		"time",
83 [OBnameserver]		"name",
84 [OBdnserver]		"dns",
85 [OBlogserver]		"log",
86 [OBcookieserver]	"cookie",
87 [OBlprserver]		"lpr",
88 [OBimpressserver]	"impress",
89 [OBrlserver]		"rl",
90 [OBhostname]		"host",
91 [OBbflen]		"bflen",
92 [OBdumpfile]		"dumpfile",
93 [OBdomainname]		"dom",
94 [OBswapserver]		"swap",
95 [OBrootpath]		"rootpath",
96 [OBextpath]		"extpath",
97 [OBipforward]		"ipforward",
98 [OBnonlocal]		"nonlocal",
99 [OBpolicyfilter]	"policyfilter",
100 [OBmaxdatagram]		"maxdatagram",
101 [OBttl]			"ttl",
102 [OBpathtimeout]		"pathtimeout",
103 [OBpathplateau]		"pathplateau",
104 [OBmtu]			"mtu",
105 [OBsubnetslocal]	"subnetslocal",
106 [OBbaddr]		"baddr",
107 [OBdiscovermask]	"discovermask",
108 [OBsupplymask]		"supplymask",
109 [OBdiscoverrouter]	"discoverrouter",
110 [OBrsserver]		"rsserver",
111 [OBstaticroutes]	"staticroutes",
112 [OBtrailerencap]	"trailerencap",
113 [OBarptimeout]		"arptimeout",
114 [OBetherencap]		"etherencap",
115 [OBtcpttl]		"tcpttl",
116 [OBtcpka]		"tcpka",
117 [OBtcpkag]		"tcpkag",
118 [OBnisdomain]		"nisdomain",
119 [OBniserver]		"niserver",
120 [OBntpserver]		"ntpserver",
121 [OBvendorinfo]		"vendorinfo",
122 [OBnetbiosns]		"NBns",
123 [OBnetbiosdds]		"NBdds",
124 [OBnetbiostype]		"NBtype",
125 [OBnetbiosscope]	"NBscope",
126 [OBxfontserver]		"xfont",
127 [OBxdispmanager]	"xdisp",
128 [OBnisplusdomain]	"NPdomain",
129 [OBnisplusserver]	"NP",
130 [OBhomeagent]		"homeagent",
131 [OBsmtpserver]		"smtp",
132 [OBpop3server]		"pop3",
133 [OBnntpserver]		"nntp",
134 [OBwwwserver]		"www",
135 [OBfingerserver]	"finger",
136 [OBircserver]		"ircserver",
137 [OBstserver]		"stserver",
138 [OBstdaserver]		"stdaserver",
139 
140 /* dhcp options */
141 [ODipaddr]		"ip",
142 [ODlease]		"leas",
143 [ODoverload]		"overload",
144 [ODtype]		"typ",
145 [ODserverid]		"sid",
146 [ODparams]		"params",
147 [ODmessage]		"message",
148 [ODmaxmsg]		"maxmsg",
149 [ODrenewaltime]		"renewaltime",
150 [ODrebindingtime]	"rebindingtime",
151 [ODvendorclass]		"vendorclass",
152 [ODclientid]		"cid",
153 [ODtftpserver]		"tftpserver",
154 [ODbootfile]		"bf",
155 };
156 
157 void	addropt(Req*, int, uchar*);
158 void	addrsopt(Req*, int, uchar**, int);
159 void	arpenter(uchar*, uchar*);
160 void	bootp(Req*);
161 void	byteopt(Req*, int, uchar);
162 void	dhcp(Req*);
163 void	fatal(int, char*, ...);
164 void	hexopt(Req*, int, char*);
165 void	longopt(Req*, int, long);
166 void	maskopt(Req*, int, uchar*);
167 void	miscoptions(Req*, uchar*);
168 int	openlisten(char *net);
169 void	parseoptions(Req*);
170 void	proto(Req*, int);
171 void	rcvdecline(Req*);
172 void	rcvdiscover(Req*);
173 void	rcvinform(Req*);
174 void	rcvrelease(Req*);
175 void	rcvrequest(Req*);
176 char*	readsysname(void);
177 void	remrequested(Req*, int);
178 void	sendack(Req*, uchar*, int, int);
179 void	sendnak(Req*, char*);
180 void	sendoffer(Req*, uchar*, int);
181 void	stringopt(Req*, int, char*);
182 void	termopt(Req*);
183 int	validip(uchar*);
184 void	vectoropt(Req*, int, uchar*, int);
185 void	warning(int, char*, ...);
186 void	logdhcp(Req*);
187 void	logdhcpout(Req *, char *);
188 int	readlast(int, uchar*, int);
189 
190 void
191 timestamp(char *tag)
192 {
193 	ulong t;
194 
195 	t = nsec()/1000;
196 	syslog(0, blog, "%s %lud", tag, t - start);
197 }
198 
199 void
200 usage(void)
201 {
202 	fprint(2, "usage: dhcp [-dmsnp] [-f directory] [-x netmtpt] [-M minlease] addr n [addr n ...]\n");
203 	exits("usage");
204 }
205 
206 void
207 main(int argc, char **argv)
208 {
209 	int i, n, fd;
210 	char *p;
211 	uchar ip[IPaddrlen];
212 	Req r;
213 
214 	setnetmtpt(net, sizeof(net), nil);
215 
216 	fmtinstall('E', eipfmt);
217 	fmtinstall('I', eipfmt);
218 	fmtinstall('V', eipfmt);
219 	fmtinstall('M', eipfmt);
220 	ARGBEGIN {
221 	case 'm':
222 		mute = 1;
223 		break;
224 	case 'd':
225 		debug = 1;
226 		break;
227 	case 'f':
228 		p = ARGF();
229 		if(p == nil)
230 			usage();
231 		ndbfile = p;
232 		break;
233 	case 's':
234 		slow = 1;
235 		break;
236 	case 'n':
237 		nobootp = 1;
238 		break;
239 	case 'p':
240 		pptponly = 1;
241 		break;
242 	case 'x':
243 		p = ARGF();
244 		if(p == nil)
245 			usage();
246 		setnetmtpt(net, sizeof(net), p);
247 		break;
248 	case 'M':
249 		p = ARGF();
250 		if(p == nil)
251 			usage();
252 		minlease = atoi(p);
253 		if(minlease <= 0)
254 			minlease = MinLease;
255 		break;
256 	} ARGEND;
257 
258 	while(argc > 1){
259 		parseip(ip, argv[0]);
260 		if(!validip(ip))
261 			usage();
262 		n = atoi(argv[1]);
263 		if(n <= 0)
264 			usage();
265 		initbinding(ip, n);
266 		argc -= 2;
267 		argv += 2;
268 	}
269 
270 	/* for debugging */
271 	for(i = 0; i < 256; i++)
272 		if(optname[i] == 0)
273 			optname[i] = smprint("%d", i);
274 
275 	/* what is my name? */
276 	p = readsysname();
277 	strcpy(mysysname, p);
278 
279 	/* put process in background */
280 	if(!debug) switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
281 	case -1:
282 		fatal(1, "fork");
283 	case 0:
284 		break;
285 	default:
286 		exits(0);
287 	}
288 
289 	chdir(TFTP);
290 	fd = openlisten(net);
291 
292 	for(;;){
293 		memset(&r, 0, sizeof(r));
294 		r.fd = fd;
295 		n = readlast(r.fd, r.buf, sizeof(r.buf));
296 		if(n < OUdphdrsize)
297 			fatal(1, "error reading requests");
298 		start = nsec()/1000;
299 		op = optbuf;
300 		*op = 0;
301 		proto(&r, n);
302 		if(r.id != nil)
303 			free(r.id);
304 	}
305 }
306 
307 void
308 proto(Req *rp, int n)
309 {
310 	uchar relip[IPaddrlen];
311 	char buf[64];
312 
313 	now = time(0);
314 
315 	rp->e = rp->buf + n;
316 	rp->bp = (Bootp*)rp->buf;
317 	rp->up = (OUdphdr*)rp->buf;
318 	rp->max = rp->buf + OUdphdrsize + MINSUPPORTED - IPUDPHDRSIZE;
319 	rp->p = rp->bp->optdata;
320 	v4tov6(rp->giaddr, rp->bp->giaddr);
321 	v4tov6(rp->ciaddr, rp->bp->ciaddr);
322 
323 	if(pptponly && rp->bp->htype != 0)
324 		return;
325 
326 	ipifcs = readipifc(net, ipifcs, -1);
327 	if(validip(rp->giaddr))
328 		ipmove(relip, rp->giaddr);
329 	else if(validip(rp->up->raddr))
330 		ipmove(relip, rp->up->raddr);
331 	else
332 		ipmove(relip, rp->up->laddr);
333 	if(rp->e < (uchar*)rp->bp->sname){
334 		warning(0, "packet too short");
335 		return;
336 	}
337 	if(rp->bp->op != Bootrequest){
338 		warning(0, "not bootrequest");
339 		return;
340 	}
341 
342 	if(rp->e >= rp->bp->optdata){
343 		if(memcmp(rp->bp->optmagic, plan9opt, sizeof(rp->bp->optmagic)) == 0)
344 			rp->p9request = 1;
345 		if(memcmp(rp->bp->optmagic, genericopt, sizeof(rp->bp->optmagic)) == 0) {
346 			rp->genrequest = 1;
347 			parseoptions(rp);
348 		}
349 	}
350 	rp->p = rp->bp->optdata;
351 
352 	/*  If no id is specified, make one from the hardware address
353 	 *  of the target.  We assume all zeros is not a hardware address
354 	 *  which could be a mistake.
355 	 */
356 	if(rp->id == nil){
357 		if(rp->bp->hlen > Maxhwlen){
358 			warning(0, "hlen %d", rp->bp->hlen);
359 			return;
360 		}
361 		if(memcmp(zeros, rp->bp->chaddr, rp->bp->hlen) == 0){
362 			warning(0, "no chaddr");
363 			return;
364 		}
365 		sprint(buf, "hwa%2.2ux_", rp->bp->htype);
366 		rp->id = tohex(buf, rp->bp->chaddr, rp->bp->hlen);
367 	}
368 
369 	/* info about gateway */
370 	if(lookupip(relip, &rp->gii, 1) < 0){
371 		warning(0, "lookupip failed");
372 		return;
373 	}
374 
375 	/* info about target system */
376 	if(lookup(rp->bp, &rp->ii, &rp->gii) == 0)
377 		if(rp->ii.indb && rp->ii.dhcpgroup[0] == 0)
378 			rp->staticbinding = 1;
379 
380 	if(rp->dhcptype)
381 		dhcp(rp);
382 	else
383 		bootp(rp);
384 timestamp("done");
385 }
386 
387 void
388 dhcp(Req *rp)
389 {
390 	logdhcp(rp);
391 
392 	switch(rp->dhcptype){
393 	case Discover:
394 		if(slow)
395 			sleep(500);
396 		rcvdiscover(rp);
397 		break;
398 	case Request:
399 		rcvrequest(rp);
400 		break;
401 	case Decline:
402 		rcvdecline(rp);
403 		break;
404 	case Release:
405 		rcvrelease(rp);
406 		break;
407 	case Inform:
408 		rcvinform(rp);
409 		break;
410 	}
411 }
412 
413 void
414 rcvdiscover(Req *rp)
415 {
416 	Binding *b, *nb;
417 
418 	if(rp->staticbinding){
419 		sendoffer(rp, rp->ii.ipaddr, StaticLease);
420 		return;
421 	}
422 
423 	/*
424 	 *  first look for an outstanding offer
425 	 */
426 	b = idtooffer(rp->id, &rp->gii);
427 
428 	/*
429 	 * rfc2131 says:
430 	 *   If an address is available, the new address
431 	 *   SHOULD be chosen as follows:
432 	 *
433 	 *      o The client's current address as recorded in the client's current
434 	 *        binding, ELSE
435 	 *
436 	 *      o The client's previous address as recorded in the client's (now
437 	 *        expired or released) binding, if that address is in the server's
438 	 *        pool of available addresses and not already allocated, ELSE
439 	 *
440 	 *      o The address requested in the 'Requested IP Address' option, if that
441 	 *        address is valid and not already allocated, ELSE
442 	 *
443 	 *      o A new address allocated from the server's pool of available
444 	 *        addresses; the address is selected based on the subnet from which
445 	 *        the message was received (if 'giaddr' is 0) or on the address of
446 	 *        the relay agent that forwarded the message ('giaddr' when not 0).
447 	 */
448 	if(b == nil){
449 		b = idtobinding(rp->id, &rp->gii, 1);
450 		if(b && b->boundto && strcmp(b->boundto, rp->id) != 0)
451 		if(validip(rp->ip) && samenet(rp->ip, &rp->gii)){
452 			nb = iptobinding(rp->ip, 0);
453 			if(nb && nb->lease < now)
454 				b = nb;
455 		}
456 	}
457 	if(b == nil){
458 		warning(0, "!Discover(%s via %I): no binding %I",
459 			rp->id, rp->gii.ipaddr, rp->ip);
460 		return;
461 	}
462 	mkoffer(b, rp->id, rp->leasetime);
463 	sendoffer(rp, b->ip, b->offer);
464 }
465 
466 void
467 rcvrequest(Req *rp)
468 {
469 	Binding *b;
470 
471 	if(validip(rp->server)){
472 		/* this is a reply to an offer - SELECTING */
473 
474 		/* check for hard assignment */
475 		if(rp->staticbinding){
476 			if(forme(rp->server))
477 				sendack(rp, rp->ii.ipaddr, StaticLease, 1);
478 			else
479 				warning(0, "!Request(%s via %I): for server %I not me",
480 					rp->id, rp->gii.ipaddr, rp->server);
481 			return;
482 		}
483 
484 		b = idtooffer(rp->id, &rp->gii);
485 
486 		/* if we don't have an offer, nak */
487 		if(b == nil){
488 			warning(0, "!Request(%s via %I): no offer",
489 				rp->id, rp->gii.ipaddr);
490 			if(forme(rp->server))
491 				sendnak(rp, "no offer for you");
492 			return;
493 		}
494 
495 		/* if not for me, retract offer */
496 		if(!forme(rp->server)){
497 			b->expoffer = 0;
498 			warning(0, "!Request(%s via %I): for server %I not me",
499 				rp->id, rp->gii.ipaddr, rp->server);
500 			return;
501 		}
502 
503 		/*
504 		 *  if the client is confused about what we offered, nak.
505 		 *  client really shouldn't be specifying this when selecting
506 		 */
507 		if(validip(rp->ip) && ipcmp(rp->ip, b->ip) != 0){
508 			warning(0, "!Request(%s via %I): requests %I, not %I",
509 				rp->id, rp->gii.ipaddr, rp->ip, b->ip);
510 			sendnak(rp, "bad ip address option");
511 			return;
512 		}
513 		if(commitbinding(b) < 0){
514 			warning(0, "!Request(%s via %I): can't commit %I",
515 				rp->id, rp->gii.ipaddr, b->ip);
516 			sendnak(rp, "can't commit binding");
517 			return;
518 		}
519 		sendack(rp, b->ip, b->offer, 1);
520 	} else if(validip(rp->ip)){
521 		/*
522 		 *  checking address/net - INIT-REBOOT
523 		 *
524 		 *  This is a rebooting client that remembers its old
525 		 *  address.
526 		 */
527 		/* check for hard assignment */
528 		if(rp->staticbinding){
529 			if(memcmp(rp->ip, rp->ii.ipaddr, IPaddrlen) != 0){
530 				warning(0, "!Request(%s via %I): %I not valid for %E",
531 					rp->id, rp->gii.ipaddr, rp->ip, rp->bp->chaddr);
532 				sendnak(rp, "not valid");
533 			}
534 			sendack(rp, rp->ii.ipaddr, StaticLease, 1);
535 			return;
536 		}
537 
538 		/* make sure the network makes sense */
539 		if(!samenet(rp->ip, &rp->gii)){
540 			warning(0, "!Request(%s via %I): bad forward of %I",
541 				rp->id, rp->gii.ipaddr, rp->ip);
542 			sendnak(rp, "wrong network");
543 			return;
544 		}
545 		b = iptobinding(rp->ip, 0);
546 		if(b == nil){
547 			warning(0, "!Request(%s via %I): no binding for %I for",
548 				rp->id, rp->gii.ipaddr, rp->ip);
549 			return;
550 		}
551 		if(memcmp(rp->ip, b->ip, IPaddrlen) != 0 || now > b->lease){
552 			warning(0, "!Request(%s via %I): %I not valid",
553 				rp->id, rp->gii.ipaddr, rp->ip);
554 			sendnak(rp, "not valid");
555 			return;
556 		}
557 		b->offer = b->lease - now;
558 		sendack(rp, b->ip, b->offer, 1);
559 	} else if(validip(rp->ciaddr)){
560 		/*
561 		 *  checking address - RENEWING or REBINDING
562 		 *
563 		 *  these states are indistinguishable in our action.  The only
564 		 *  difference is how close to lease expiration the client is.
565 		 *  If it is really close, it broadcasts the request hoping that
566 		 *  some server will answer.
567 		 */
568 
569 		/* check for hard assignment */
570 		if(rp->staticbinding){
571 			if(ipcmp(rp->ciaddr, rp->ii.ipaddr) != 0){
572 				warning(0, "!Request(%s via %I): %I not valid",
573 					rp->id, rp->gii.ipaddr, rp->ciaddr);
574 				sendnak(rp, "not valid");
575 			}
576 			sendack(rp, rp->ii.ipaddr, StaticLease, 1);
577 			return;
578 		}
579 
580 		/* make sure the network makes sense */
581 		if(!samenet(rp->ciaddr, &rp->gii)){
582 			warning(0, "!Request(%s via %I): bad forward of %I",
583 				rp->id, rp->gii.ipaddr, rp->ip);
584 			sendnak(rp, "wrong network");
585 			return;
586 		}
587 		b = iptobinding(rp->ciaddr, 0);
588 		if(b == nil){
589 			warning(0, "!Request(%s via %I): no binding for %I",
590 				rp->id, rp->gii.ipaddr, rp->ciaddr);
591 			return;
592 		}
593 		if(ipcmp(rp->ciaddr, b->ip) != 0){
594 			warning(0, "!Request(%I via %s): %I not valid",
595 				rp->id, rp->gii.ipaddr, rp->ciaddr);
596 			sendnak(rp, "invalid ip address");
597 			return;
598 		}
599 		mkoffer(b, rp->id, rp->leasetime);
600 		if(commitbinding(b) < 0){
601 			warning(0, "!Request(%s via %I): can't commit %I",
602 				rp->id, rp->gii.ipaddr, b->ip);
603 			sendnak(rp, "can't commit binding");
604 			return;
605 		}
606 		sendack(rp, b->ip, b->offer, 1);
607 	}
608 }
609 
610 void
611 rcvdecline(Req *rp)
612 {
613 	Binding *b;
614 	char buf[64];
615 
616 	if(rp->staticbinding)
617 		return;
618 
619 	b = idtooffer(rp->id, &rp->gii);
620 	if(b == nil){
621 		warning(0, "!Decline(%s via %I): no binding",
622 			rp->id, rp->gii.ipaddr);
623 		return;
624 	}
625 
626 	/* mark ip address as in use */
627 	snprint(buf, sizeof(buf), "declined by %s", rp->id);
628 	mkoffer(b, buf, 0x7fffffff);
629 	commitbinding(b);
630 }
631 
632 void
633 rcvrelease(Req *rp)
634 {
635 	Binding *b;
636 
637 	if(rp->staticbinding)
638 		return;
639 
640 	b = idtobinding(rp->id, &rp->gii, 0);
641 	if(b == nil){
642 		warning(0, "!Release(%s via %I): no binding",
643 			rp->id, rp->gii.ipaddr);
644 		return;
645 	}
646 	if(strcmp(rp->id, b->boundto) != 0){
647 		warning(0, "!Release(%s via %I): invalid release of %I",
648 			rp->id, rp->gii.ipaddr, rp->ip);
649 		return;
650 	}
651 	warning(0, "Release(%s via %I): releasing %I", b->boundto, rp->gii.ipaddr, b->ip);
652 	if(releasebinding(b, rp->id) < 0)
653 		warning(0, "release: couldn't release");
654 }
655 
656 void
657 rcvinform(Req *rp)
658 {
659 	Binding *b;
660 
661 	if(rp->staticbinding){
662 		sendack(rp, rp->ii.ipaddr, 0, 0);
663 		return;
664 	}
665 
666 	b = iptobinding(rp->ciaddr, 0);
667 	if(b == nil){
668 		warning(0, "!Inform(%s via %I): no binding for %I",
669 			rp->id, rp->gii.ipaddr, rp->ip);
670 		return;
671 	}
672 	sendack(rp, b->ip, 0, 0);
673 }
674 
675 int
676 setsiaddr(uchar *siaddr, uchar *saddr, uchar *laddr)
677 {
678 	if(ipcmp(saddr, IPnoaddr) != 0){
679 		v6tov4(siaddr, saddr);
680 		return 0;
681 	} else {
682 		v6tov4(siaddr, laddr);
683 		return 1;
684 	}
685 }
686 
687 void
688 sendoffer(Req *rp, uchar *ip, int offer)
689 {
690 	int n;
691 	ushort flags;
692 	Bootp *bp;
693 	OUdphdr *up;
694 
695 	bp = rp->bp;
696 	up = rp->up;
697 
698 	/*
699 	 *  set destination
700 	 */
701 	flags = nhgets(bp->flags);
702 	if(validip(rp->giaddr)){
703 		ipmove(up->raddr, rp->giaddr);
704 		hnputs(up->rport, 67);
705 	} else if(flags & Fbroadcast){
706 		ipmove(up->raddr, IPv4bcast);
707 		hnputs(up->rport, 68);
708 	} else {
709 		ipmove(up->raddr, ip);
710 		if(bp->htype == 1)
711 			arpenter(up->raddr, bp->chaddr);
712 		hnputs(up->rport, 68);
713 	}
714 
715 	/*
716 	 *  fill in standard bootp part
717 	 */
718 	bp->op = Bootreply;
719 	bp->hops = 0;
720 	hnputs(bp->secs, 0);
721 	memset(bp->ciaddr, 0, sizeof(bp->ciaddr));
722 	v6tov4(bp->giaddr, rp->giaddr);
723 	v6tov4(bp->yiaddr, ip);
724 	setsiaddr(bp->siaddr, rp->ii.tftp, up->laddr);
725 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
726 	strncpy(bp->file, rp->ii.bootf, sizeof(bp->file));
727 
728 	/*
729 	 *  set options
730 	 */
731 	byteopt(rp, ODtype, Offer);
732 	longopt(rp, ODlease, offer);
733 	addropt(rp, ODserverid, up->laddr);
734 	miscoptions(rp, ip);
735 	termopt(rp);
736 
737 	logdhcpout(rp, "Offer");
738 
739 	/*
740 	 *  send
741 	 */
742 	n = rp->p - rp->buf;
743 	if(!mute && write(rp->fd, rp->buf, n) != n)
744 		warning(0, "offer: write failed: %r");
745 }
746 
747 void
748 sendack(Req *rp, uchar *ip, int offer, int sendlease)
749 {
750 	int n;
751 	ushort flags;
752 	Bootp *bp;
753 	OUdphdr *up;
754 
755 	bp = rp->bp;
756 	up = rp->up;
757 
758 	/*
759 	 *  set destination
760 	 */
761 	flags = nhgets(bp->flags);
762 	if(validip(rp->giaddr)){
763 		ipmove(up->raddr, rp->giaddr);
764 		hnputs(up->rport, 67);
765 	} else if(flags & Fbroadcast){
766 		ipmove(up->raddr, IPv4bcast);
767 		hnputs(up->rport, 68);
768 	} else {
769 		ipmove(up->raddr, ip);
770 		if(bp->htype == 1)
771 			arpenter(up->raddr, bp->chaddr);
772 		hnputs(up->rport, 68);
773 	}
774 
775 	/*
776 	 *  fill in standard bootp part
777 	 */
778 	bp->op = Bootreply;
779 	bp->hops = 0;
780 	hnputs(bp->secs, 0);
781 	v6tov4(bp->giaddr, rp->giaddr);
782 	v6tov4(bp->yiaddr, ip);
783 	setsiaddr(bp->siaddr, rp->ii.tftp, up->laddr);
784 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
785 	strncpy(bp->file, rp->ii.bootf, sizeof(bp->file));
786 
787 	/*
788 	 *  set options
789 	 */
790 	byteopt(rp, ODtype, Ack);
791 	if(sendlease){
792 		longopt(rp, ODlease, offer);
793 	}
794 	addropt(rp, ODserverid, up->laddr);
795 	miscoptions(rp, ip);
796 	termopt(rp);
797 
798 	logdhcpout(rp, "Ack");
799 
800 	/*
801 	 *  send
802 	 */
803 	n = rp->p - rp->buf;
804 	if(!mute && write(rp->fd, rp->buf, n) != n)
805 		warning(0, "ack: write failed: %r");
806 }
807 
808 void
809 sendnak(Req *rp, char *msg)
810 {
811 	int n;
812 	Bootp *bp;
813 	OUdphdr *up;
814 
815 	bp = rp->bp;
816 	up = rp->up;
817 
818 	/*
819 	 *  set destination (always broadcast)
820 	 */
821 	if(validip(rp->giaddr)){
822 		ipmove(up->raddr, rp->giaddr);
823 		hnputs(up->rport, 67);
824 	} else {
825 		ipmove(up->raddr, IPv4bcast);
826 		hnputs(up->rport, 68);
827 	}
828 
829 	/*
830 	 *  fill in standard bootp part
831 	 */
832 	bp->op = Bootreply;
833 	bp->hops = 0;
834 	hnputs(bp->secs, 0);
835 	v6tov4(bp->giaddr, rp->giaddr);
836 	memset(bp->ciaddr, 0, sizeof(bp->ciaddr));
837 	memset(bp->yiaddr, 0, sizeof(bp->yiaddr));
838 	memset(bp->siaddr, 0, sizeof(bp->siaddr));
839 
840 	/*
841 	 *  set options
842 	 */
843 	byteopt(rp, ODtype, Nak);
844 	addropt(rp, ODserverid, up->laddr);
845 	if(msg)
846 		stringopt(rp, ODmessage, msg);
847 	if(strncmp(rp->id, "id", 2) == 0)
848 		hexopt(rp, ODclientid, rp->id+2);
849 	termopt(rp);
850 
851 	logdhcpout(rp, "Nak");
852 
853 	/*
854 	 *  send nak
855 	 */
856 	n = rp->p - rp->buf;
857 	if(!mute && write(rp->fd, rp->buf, n) != n)
858 		warning(0, "nak: write failed: %r");
859 }
860 
861 void
862 bootp(Req *rp)
863 {
864 	int n;
865 	Bootp *bp;
866 	OUdphdr *up;
867 	ushort flags;
868 	Iplifc *lifc;
869 	Info *iip;
870 
871 	warning(0, "bootp %s %I->%I from %s via %I, file %s",
872 		rp->genrequest ? "generic" : (rp->p9request ? "p9" : ""),
873 		rp->up->raddr, rp->up->laddr,
874 		rp->id, rp->gii.ipaddr,
875 		rp->bp->file);
876 
877 	if(nobootp)
878 		return;
879 
880 	bp = rp->bp;
881 	up = rp->up;
882 	iip = &rp->ii;
883 
884 	if(rp->staticbinding == 0){
885 		warning(0, "bootp from unknown %s via %I", rp->id, rp->gii.ipaddr);
886 		return;
887 	}
888 
889 	/* ignore if not for us */
890 	if(*bp->sname){
891 		if(strcmp(bp->sname, mysysname) != 0){
892 			bp->sname[20] = 0;
893 			warning(0, "bootp for server %s", bp->sname);
894 			return;
895 		}
896 	} else if(slow)
897 		sleep(500);
898 
899 	/* ignore if we don't know what file to load */
900 	if(*bp->file == 0){
901 		if(rp->genrequest && *iip->bootf2)	/* if not plan 9 and we have an alternate file... */
902 			strncpy(bp->file, iip->bootf2, sizeof(bp->file));
903 		else if(*iip->bootf)
904 			strncpy(bp->file, iip->bootf, sizeof(bp->file));
905 		else if(*bp->sname)		/* if we were asked, respond no matter what */
906 			bp->file[0] = '\0';
907 		else {
908 			warning(0, "no bootfile for %I", iip->ipaddr);
909 			return;
910 		}
911 	}
912 
913 	/* ignore if the file is unreadable */
914 	if((!rp->genrequest) && bp->file[0] && access(bp->file, 4) < 0){
915 		warning(0, "inaccessible bootfile1 %s", bp->file);
916 		return;
917 	}
918 
919 	bp->op = Bootreply;
920 	v6tov4(bp->yiaddr, iip->ipaddr);
921 	if(rp->p9request){
922 		warning(0, "p9bootp: %I", iip->ipaddr);
923 		memmove(bp->optmagic, plan9opt, 4);
924 		if(iip->gwip == 0)
925 			v4tov6(iip->gwip, bp->giaddr);
926 		rp->p += sprint((char*)rp->p, "%V %I %I %I", iip->ipmask+IPv4off, iip->fsip,
927 				iip->auip, iip->gwip);
928 		sprint(optbuf, "%s", (char*)(bp->optmagic));
929 	} else if(rp->genrequest){
930 		warning(0, "genericbootp: %I", iip->ipaddr);
931 		memmove(bp->optmagic, genericopt, 4);
932 		miscoptions(rp, iip->ipaddr);
933 		termopt(rp);
934 	} else if(iip->vendor[0] != 0) {
935 		warning(0, "bootp vendor field: %s", iip->vendor);
936 		memset(rp->p, 0, 128-4);
937 		rp->p += sprint((char*)bp->optmagic, "%s", iip->vendor);
938 	} else {
939 		memset(rp->p, 0, 128-4);
940 		rp->p += 128-4;
941 	}
942 
943 	/*
944 	 *  set destination
945 	 */
946 	flags = nhgets(bp->flags);
947 	if(validip(rp->giaddr)){
948 		ipmove(up->raddr, rp->giaddr);
949 		hnputs(up->rport, 67);
950 	} else if(flags & Fbroadcast){
951 		ipmove(up->raddr, IPv4bcast);
952 		hnputs(up->rport, 68);
953 	} else {
954 		v4tov6(up->raddr, bp->yiaddr);
955 		if(bp->htype == 1)
956 			arpenter(up->raddr, bp->chaddr);
957 		hnputs(up->rport, 68);
958 	}
959 
960 	/*
961 	 *  select best local address if destination is directly connected
962 	 */
963 	lifc = findlifc(up->raddr);
964 	if(lifc)
965 		ipmove(up->laddr, lifc->ip);
966 
967 	/*
968 	 *  our identity
969 	 */
970 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
971 
972 	/*
973 	 *  set tftp server
974 	 */
975 	setsiaddr(bp->siaddr, iip->tftp, up->laddr);
976 	if(rp->genrequest && *iip->bootf2)
977 		setsiaddr(bp->siaddr, iip->tftp2, up->laddr);
978 
979 	/*
980 	 * RFC 1048 says that we must pad vendor field with
981 	 * zeros until we have a 64 byte field.
982 	 */
983 	n = rp->p - rp->bp->optdata;
984 	if(n < 64-4) {
985 		memset(rp->p, 0, (64-4)-n);
986 		rp->p += (64-4)-n;
987 	}
988 
989 	/*
990 	 *  send
991 	 */
992 	n = rp->p - rp->buf;
993 	if(!mute && write(rp->fd, rp->buf, n) != n)
994 		warning(0, "bootp: write failed: %r");
995 
996 	warning(0, "bootp via %I: file %s xid(%ux)flag(%ux)ci(%V)gi(%V)yi(%V)si(%V) %s",
997 			up->raddr, bp->file, nhgetl(bp->xid), nhgets(bp->flags),
998 			bp->ciaddr, bp->giaddr, bp->yiaddr, bp->siaddr,
999 			optbuf);
1000 }
1001 
1002 void
1003 parseoptions(Req *rp)
1004 {
1005 	int n, c, code;
1006 	uchar *o, *p;
1007 
1008 	p = rp->p;
1009 
1010 	while(p < rp->e){
1011 		code = *p++;
1012 		if(code == 255)
1013 			break;
1014 		if(code == 0)
1015 			continue;
1016 
1017 		/* ignore anything that's too long */
1018 		n = *p++;
1019 		o = p;
1020 		p += n;
1021 		if(p > rp->e)
1022 			return;
1023 
1024 		switch(code){
1025 		case ODipaddr:	/* requested ip address */
1026 			if(n == IPv4addrlen)
1027 				v4tov6(rp->ip, o);
1028 			break;
1029 		case ODlease:	/* requested lease time */
1030 			rp->leasetime = nhgetl(o);
1031 			if(rp->leasetime > MaxLease || rp->leasetime < 0)
1032 				rp->leasetime = MaxLease;
1033 			break;
1034 		case ODtype:
1035 			c = *o;
1036 			if(c < 10 && c > 0)
1037 				rp->dhcptype = c;
1038 			break;
1039 		case ODserverid:
1040 			if(n == IPv4addrlen)
1041 				v4tov6(rp->server, o);
1042 			break;
1043 		case ODmessage:
1044 			if(n > sizeof rp->msg-1)
1045 				n = sizeof rp->msg-1;
1046 			memmove(rp->msg, o, n);
1047 			rp->msg[n] = 0;
1048 			break;
1049 		case ODmaxmsg:
1050 			c = nhgets(o);
1051 			c -= 28;
1052 			c += OUdphdrsize;
1053 			if(c > 0)
1054 				rp->max = rp->buf + c;
1055 			break;
1056 		case ODclientid:
1057 			if(n <= 1)
1058 				break;
1059 			rp->id = toid( o, n);
1060 			break;
1061 		case ODparams:
1062 			if(n > sizeof(rp->requested))
1063 				n = sizeof(rp->requested);
1064 			memmove(rp->requested, o, n);
1065 			break;
1066 		case ODvendorclass:
1067 			if(n >= sizeof(rp->vendorclass))
1068 				n = sizeof(rp->vendorclass)-1;
1069 			memmove(rp->vendorclass, o, n);
1070 			rp->vendorclass[n] = 0;
1071 			if(strncmp((char*)rp->vendorclass, "p9-", 3) == 0)
1072 				strcpy(rp->cputype, (char*)rp->vendorclass+3);
1073 			break;
1074 		case OBend:
1075 			return;
1076 		}
1077 	}
1078 }
1079 
1080 void
1081 remrequested(Req *rp, int opt)
1082 {
1083 	uchar *p;
1084 
1085 	p = memchr(rp->requested, opt, sizeof(rp->requested));
1086 	if(p != nil)
1087 		*p = OBpad;
1088 }
1089 
1090 void
1091 miscoptions(Req *rp, uchar *ip)
1092 {
1093 	char *p;
1094 	int i, j;
1095 	uchar *addrs[2];
1096 	uchar x[2*IPaddrlen];
1097 	uchar vopts[64];
1098 	uchar *op, *omax;
1099 	char *attr[100], **a;
1100 	int na;
1101 	Ndbtuple *t;
1102 
1103 	addrs[0] = x;
1104 	addrs[1] = x+IPaddrlen;
1105 
1106 	/* always supply these */
1107 	maskopt(rp, OBmask, rp->gii.ipmask);
1108 	if(validip(rp->gii.gwip)){
1109 		remrequested(rp, OBrouter);
1110 		addropt(rp, OBrouter, rp->gii.gwip);
1111 	} else if(validip(rp->giaddr)){
1112 		remrequested(rp, OBrouter);
1113 		addropt(rp, OBrouter, rp->giaddr);
1114 	}
1115 
1116 	// OBhostname for the HP4000M switches
1117 	// (this causes NT to log infinite errors - tough shit )
1118 	if(*rp->ii.domain){
1119 		remrequested(rp, OBhostname);
1120 		stringopt(rp, OBhostname, rp->ii.domain);
1121 	}
1122 	if(*rp->ii.rootpath)
1123 		stringopt(rp, OBrootpath, rp->ii.rootpath);
1124 
1125 	/* figure out what we need to lookup */
1126 	na = 0;
1127 	a = attr;
1128 	if(*rp->ii.domain == 0)
1129 		a[na++] = "dom";
1130 	for(i = 0; i < sizeof(rp->requested); i++)
1131 		switch(rp->requested[i]){
1132 		case OBrouter:
1133 			a[na++] = "@ipgw";
1134 			break;
1135 		case OBdnserver:
1136 			a[na++] = "@dns";
1137 			break;
1138 		case OBnetbiosns:
1139 			a[na++] = "@wins";
1140 			break;
1141 		case OBsmtpserver:
1142 			a[na++] = "@smtp";
1143 			break;
1144 		case OBpop3server:
1145 			a[na++] = "@pop3";
1146 			break;
1147 		case OBwwwserver:
1148 			a[na++] = "@www";
1149 			break;
1150 		case OBntpserver:
1151 			a[na++] = "@ntp";
1152 			break;
1153 		case OBtimeserver:
1154 			a[na++] = "@time";
1155 			break;
1156 		}
1157 	if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0
1158 	|| strncmp((char*)rp->vendorclass, "p9-", 3) == 0){
1159 		a[na++] = "@fs";
1160 		a[na++] = "@auth";
1161 	}
1162 	t = lookupinfo(ip, a, na);
1163 
1164 	/* lookup anything we might be missing */
1165 	if(*rp->ii.domain == 0)
1166 		lookupname(rp->ii.domain, t);
1167 
1168 	/* add any requested ones that we know about */
1169 	for(i = 0; i < sizeof(rp->requested); i++)
1170 		switch(rp->requested[i]){
1171 		case OBrouter:
1172 			j = lookupserver("ipgw", addrs, t);
1173 			addrsopt(rp, OBrouter, addrs, j);
1174 			break;
1175 		case OBdnserver:
1176 			j = lookupserver("dns", addrs, t);
1177 			addrsopt(rp, OBdnserver, addrs, j);
1178 			break;
1179 		case OBhostname:
1180 			if(*rp->ii.domain)
1181 				stringopt(rp, OBhostname, rp->ii.domain);
1182 			break;
1183 		case OBdomainname:
1184 			p = strchr(rp->ii.domain, '.');
1185 			if(p)
1186 				stringopt(rp, OBdomainname, p+1);
1187 			break;
1188 		case OBnetbiosns:
1189 			j = lookupserver("wins", addrs, t);
1190 			addrsopt(rp, OBnetbiosns, addrs, j);
1191 			break;
1192 		case OBnetbiostype:
1193 			/* p-node: peer to peer WINS queries */
1194 			byteopt(rp, OBnetbiostype, 0x2);
1195 			break;
1196 		case OBsmtpserver:
1197 			j = lookupserver("smtp", addrs, t);
1198 			addrsopt(rp, OBsmtpserver, addrs, j);
1199 			break;
1200 		case OBpop3server:
1201 			j = lookupserver("pop3", addrs, t);
1202 			addrsopt(rp, OBpop3server, addrs, j);
1203 			break;
1204 		case OBwwwserver:
1205 			j = lookupserver("www", addrs, t);
1206 			addrsopt(rp, OBwwwserver, addrs, j);
1207 			break;
1208 		case OBntpserver:
1209 			j = lookupserver("ntp", addrs, t);
1210 			addrsopt(rp, OBntpserver, addrs, j);
1211 			break;
1212 		case OBtimeserver:
1213 			j = lookupserver("time", addrs, t);
1214 			addrsopt(rp, OBtimeserver, addrs, j);
1215 			break;
1216 		case OBttl:
1217 			byteopt(rp, OBttl, 255);
1218 			break;
1219 		}
1220 
1221 	// add plan9 specific options
1222 	if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0
1223 	|| strncmp((char*)rp->vendorclass, "p9-", 3) == 0){
1224 		// point to temporary area
1225 		op = rp->p;
1226 		omax = rp->max;
1227 		rp->p = vopts;
1228 		rp->max = vopts + sizeof(vopts) - 1;
1229 
1230 		j = lookupserver("fs", addrs, t);
1231 		addrsopt(rp, OP9fs, addrs, j);
1232 		j = lookupserver("auth", addrs, t);
1233 		addrsopt(rp, OP9auth, addrs, j);
1234 
1235 		// point back
1236 		j = rp->p - vopts;
1237 		rp->p = op;
1238 		rp->max = omax;
1239 		vectoropt(rp, OBvendorinfo, vopts, j);
1240 	}
1241 
1242 	ndbfree(t);
1243 }
1244 
1245 int
1246 openlisten(char *net)
1247 {
1248 	int fd, cfd;
1249 	char data[128];
1250 	char devdir[40];
1251 
1252 	sprint(data, "%s/udp!*!bootp", net);
1253 	cfd = announce(data, devdir);
1254 	if(cfd < 0)
1255 		fatal(1, "can't announce");
1256 	if(fprint(cfd, "headers") < 0)
1257 		fatal(1, "can't set header mode");
1258 	fprint(cfd, "oldheaders");
1259 
1260 	sprint(data, "%s/data", devdir);
1261 
1262 	fd = open(data, ORDWR);
1263 	if(fd < 0)
1264 		fatal(1, "open udp data");
1265 	return fd;
1266 }
1267 
1268 void
1269 fatal(int syserr, char *fmt, ...)
1270 {
1271 	char buf[ERRMAX];
1272 	va_list arg;
1273 
1274 	va_start(arg, fmt);
1275 	vseprint(buf, buf+sizeof(buf), fmt, arg);
1276 	va_end(arg);
1277 	if(syserr)
1278 		syslog(1, blog, "%s: %r", buf);
1279 	else
1280 		syslog(1, blog, "%s", buf);
1281 	exits(buf);
1282 }
1283 
1284 extern void
1285 warning(int syserr, char *fmt, ...)
1286 {
1287 	char buf[256];
1288 	va_list arg;
1289 
1290 	va_start(arg, fmt);
1291 	vseprint(buf, buf+sizeof(buf), fmt, arg);
1292 	va_end(arg);
1293 	if(syserr){
1294 		syslog(0, blog, "%s: %r", buf);
1295 		if(debug)
1296 			fprint(2, "%s: %r\n", buf);
1297 	} else {
1298 		syslog(0, blog, "%s", buf);
1299 		if(debug)
1300 			fprint(2, "%s\n", buf);
1301 	}
1302 }
1303 
1304 char*
1305 readsysname(void)
1306 {
1307 	static char name[128];
1308 	char *p;
1309 	int n, fd;
1310 
1311 	fd = open("/dev/sysname", OREAD);
1312 	if(fd >= 0){
1313 		n = read(fd, name, sizeof(name)-1);
1314 		close(fd);
1315 		if(n > 0){
1316 			name[n] = 0;
1317 			return name;
1318 		}
1319 	}
1320 	p = getenv("sysname");
1321 	if(p == nil || *p == 0)
1322 		return "unknown";
1323 	return p;
1324 }
1325 
1326 extern int
1327 validip(uchar *ip)
1328 {
1329 	if(ipcmp(ip, IPnoaddr) == 0)
1330 		return 0;
1331 	if(ipcmp(ip, v4prefix) == 0)
1332 		return 0;
1333 	return 1;
1334 }
1335 
1336 void
1337 longopt(Req *rp, int t, long v)
1338 {
1339 	if(rp->p + 6 > rp->max)
1340 		return;
1341 	*rp->p++ = t;
1342 	*rp->p++ = 4;
1343 	hnputl(rp->p, v);
1344 	rp->p += 4;
1345 
1346 	op = seprint(op, oe, "%s(%ld)", optname[t], v);
1347 }
1348 
1349 void
1350 addropt(Req *rp, int t, uchar *ip)
1351 {
1352 	if(rp->p + 6 > rp->max)
1353 		return;
1354 	*rp->p++ = t;
1355 	*rp->p++ = 4;
1356 	memmove(rp->p, ip+IPv4off, 4);
1357 	rp->p += 4;
1358 
1359 	op = seprint(op, oe, "%s(%I)", optname[t], ip);
1360 }
1361 
1362 void
1363 maskopt(Req *rp, int t, uchar *ip)
1364 {
1365 	if(rp->p + 6 > rp->max)
1366 		return;
1367 	*rp->p++ = t;
1368 	*rp->p++ = 4;
1369 	memmove(rp->p, ip+IPv4off, 4);
1370 	rp->p += 4;
1371 
1372 	op = seprint(op, oe, "%s(%M)", optname[t], ip);
1373 }
1374 
1375 void
1376 addrsopt(Req *rp, int t, uchar **ip, int i)
1377 {
1378 	if(i <= 0)
1379 		return;
1380 	if(rp->p + 2 + 4*i > rp->max)
1381 		return;
1382 	*rp->p++ = t;
1383 	*rp->p++ = 4*i;
1384 	op = seprint(op, oe, "%s(", optname[t]);
1385 	while(i-- > 0){
1386 		v6tov4(rp->p, *ip);
1387 		rp->p += 4;
1388 		op = seprint(op, oe, "%I", *ip);
1389 		ip++;
1390 		if(i > 0)
1391 			op = seprint(op, oe, " ");
1392 	}
1393 	op = seprint(op, oe, ")");
1394 }
1395 
1396 void
1397 byteopt(Req *rp, int t, uchar v)
1398 {
1399 	if(rp->p + 3 > rp->max)
1400 		return;
1401 	*rp->p++ = t;
1402 	*rp->p++ = 1;
1403 	*rp->p++ = v;
1404 
1405 	op = seprint(op, oe, "%s(%d)", optname[t], v);
1406 }
1407 
1408 void
1409 termopt(Req *rp)
1410 {
1411 	if(rp->p + 1 > rp->max)
1412 		return;
1413 	*rp->p++ = OBend;
1414 }
1415 
1416 void
1417 stringopt(Req *rp, int t, char *str)
1418 {
1419 	int n;
1420 
1421 	n = strlen(str);
1422 	if(n > 255)
1423 		n = 255;
1424 	if(rp->p+n+2 > rp->max)
1425 		return;
1426 	*rp->p++ = t;
1427 	*rp->p++ = n;
1428 	memmove(rp->p, str, n);
1429 	rp->p += n;
1430 
1431 	op = seprint(op, oe, "%s(%s)", optname[t], str);
1432 }
1433 
1434 void
1435 vectoropt(Req *rp, int t, uchar *v, int n)
1436 {
1437 	int i;
1438 
1439 	if(n > 255)
1440 		n = 255;
1441 	if(rp->p+n+2 > rp->max)
1442 		return;
1443 	*rp->p++ = t;
1444 	*rp->p++ = n;
1445 	memmove(rp->p, v, n);
1446 	rp->p += n;
1447 
1448 	op = seprint(op, oe, "%s(", optname[t]);
1449 	if(n > 0)
1450 		op = seprint(op, oe, "%ud", 0);
1451 	for(i = 1; i < n; i++)
1452 		op = seprint(op, oe, " %ud", v[i]);
1453 }
1454 
1455 int
1456 fromhex(int x)
1457 {
1458 	if(x >= '0' && x <= '9')
1459 		return x - '0';
1460 	return x - 'a';
1461 }
1462 
1463 void
1464 hexopt(Req *rp, int t, char *str)
1465 {
1466 	int n;
1467 
1468 	n = strlen(str);
1469 	n /= 2;
1470 	if(n > 255)
1471 		n = 255;
1472 	if(rp->p+n+2 > rp->max)
1473 		return;
1474 	*rp->p++ = t;
1475 	*rp->p++ = n;
1476 	while(n-- > 0){
1477 		*rp->p++ = (fromhex(str[0])<<4)|fromhex(str[1]);
1478 		str += 2;
1479 	}
1480 
1481 	op = seprint(op, oe, "%s(%s)", optname[t], str);
1482 }
1483 
1484 void
1485 arpenter(uchar *ip, uchar *ether)
1486 {
1487 	int f;
1488 	char buf[256];
1489 
1490 	/* brazil */
1491 	sprint(buf, "%s/arp", net);
1492 	f = open(buf, OWRITE);
1493 	if(f < 0){
1494 		syslog(debug, blog, "open %s: %r", buf);
1495 		return;
1496 	}
1497 	fprint(f, "add ether %I %E", ip, ether);
1498 	close(f);
1499 }
1500 
1501 char *dhcpmsgname[] =
1502 {
1503 	[Discover]	"Discover",
1504 	[Offer]		"Offer",
1505 	[Request]	"Request",
1506 	[Decline]	"Decline",
1507 	[Ack]		"Ack",
1508 	[Nak]		"Nak",
1509 	[Release]	"Release",
1510 	[Inform]	"Inform",
1511 };
1512 
1513 void
1514 logdhcp(Req *rp)
1515 {
1516 	char buf[4096];
1517 	char *p, *e;
1518 	int i;
1519 
1520 	p = buf;
1521 	e = buf + sizeof(buf);
1522 	if(rp->dhcptype > 0 && rp->dhcptype <= Inform)
1523 		p = seprint(p, e, "%s(", dhcpmsgname[rp->dhcptype]);
1524 	else
1525 		p = seprint(p, e, "%d(", rp->dhcptype);
1526 	p = seprint(p, e, "%I->%I) xid(%ux)flag(%ux)", rp->up->raddr, rp->up->laddr,
1527 		nhgetl(rp->bp->xid), nhgets(rp->bp->flags));
1528 	if(rp->bp->htype == 1)
1529 		p = seprint(p, e, "ea(%E)", rp->bp->chaddr);
1530 	if(validip(rp->ciaddr))
1531 		p = seprint(p, e, "ci(%I)", rp->ciaddr);
1532 	if(validip(rp->giaddr))
1533 		p = seprint(p, e, "gi(%I)", rp->giaddr);
1534 	if(validip(rp->ip))
1535 		p = seprint(p, e, "ip(%I)", rp->ip);
1536 	if(rp->id != nil)
1537 		p = seprint(p, e, "id(%s)", rp->id);
1538 	if(rp->leasetime)
1539 		p = seprint(p, e, "leas(%d)", rp->leasetime);
1540 	if(validip(rp->server))
1541 		p = seprint(p, e, "sid(%I)", rp->server);
1542 	p = seprint(p, e, "need(");
1543 	for(i = 0; i < sizeof(rp->requested); i++)
1544 		if(rp->requested[i] != 0)
1545 			p = seprint(p, e, "%s ", optname[rp->requested[i]]);
1546 	p = seprint(p, e, ")");
1547 
1548 	USED(p);
1549 	syslog(0, blog, "%s", buf);
1550 }
1551 
1552 void
1553 logdhcpout(Req *rp, char *type)
1554 {
1555 	syslog(0, blog, "%s(%I-%I)id(%s)ci(%V)gi(%V)yi(%V)si(%V) %s",
1556 		type, rp->up->laddr, rp->up->raddr, rp->id,
1557 		rp->bp->ciaddr, rp->bp->giaddr, rp->bp->yiaddr, rp->bp->siaddr, optbuf);
1558 }
1559 
1560 /*
1561  *  if we get behind, it's useless to try answering since the sender
1562  *  will probably have retransmitted with a differnt sequence number.
1563  *  So dump all the last message in the queue.
1564  */
1565 void ding(void*, char *msg)
1566 {
1567 	if(strstr(msg, "alarm"))
1568 		noted(NCONT);
1569 	else
1570 		noted(NDFLT);
1571 }
1572 
1573 int
1574 readlast(int fd, uchar *buf, int len)
1575 {
1576 	int lastn, n;
1577 
1578 	notify(ding);
1579 
1580 	lastn = 0;
1581 	for(;;){
1582 		alarm(20);
1583 		n = read(fd, buf, len);
1584 		alarm(0);
1585 		if(n < 0){
1586 			if(lastn > 0)
1587 				return lastn;
1588 			break;
1589 		}
1590 		lastn = n;
1591 	}
1592 	return read(fd, buf, len);
1593 }
1594