1 #include <u.h>
2 #include <sys/socket.h>
3 #include <net/if_arp.h>
4 #include <netinet/ip.h>
5 #include <sys/ioctl.h>
6 #include <libc.h>
7 #include <ip.h>
8 #include <bio.h>
9 #include <ndb.h>
10 #include "dat.h"
11 
12 int bwfd;
13 int wfd;
14 
15 /* */
16 /*	ala rfc2131 */
17 /* */
18 
19 typedef struct Req Req;
20 struct Req
21 {
22 	int	fd;			/* for reply */
23 	Bootp	*bp;
24 	Udphdr	uh;
25 	Udphdr	*up;
26 	uchar	*e;			/* end of received message */
27 	uchar	*p;			/* options pointer */
28 	uchar	*max;			/* max end of reply */
29 
30 	/* expanded to v6 */
31 	uchar	ciaddr[IPaddrlen];
32 	uchar	giaddr[IPaddrlen];
33 
34 	/* parsed options */
35 	int	p9request;		/* true if this is a bootp with plan9 options */
36 	int	genrequest;		/* true if this is a bootp with generic options */
37 	int	dhcptype;		/* dhcp message type */
38 	int	leasetime;		/* dhcp lease */
39 	uchar	ip[IPaddrlen];		/* requested address */
40 	uchar	server[IPaddrlen];	/* server address */
41 	char	msg[ERRMAX];		/* error message */
42 	char	vci[32];		/* vendor class id */
43 	char	*id;			/* client id */
44 	uchar	requested[32];		/* requested params */
45 	uchar	vendorclass[32];
46 	char	cputype[32-3];
47 
48 	Info	gii;			/* about target network */
49 	Info	ii;			/* about target system */
50 	int	staticbinding;
51 
52 	uchar buf[2*1024];		/* message buffer */
53 };
54 
55 #define TFTP "/lib/tftpd"
56 char	*blog = "ipboot";
57 char	mysysname[64];
58 Ipifc	*ipifcs;
59 int	debug;
60 int	nobootp;
61 long	now;
62 int	slow;
63 char	net[256];
64 uchar xmyipaddr[IPaddrlen];
65 
66 int	pptponly;	/* only answer request that came from the pptp server */
67 int	mute;
68 int	minlease = MinLease;
69 
70 ulong	start;
71 
72 /* option magic */
73 char plan9opt[4] = { 'p', '9', ' ', ' ' };
74 char genericopt[4] = { 0x63, 0x82, 0x53, 0x63 };
75 
76 /* well known addresses */
77 uchar zeros[Maxhwlen];
78 
79 /* option debug buffer */
80 char optbuf[1024];
81 char *op;
82 char *oe = optbuf + sizeof(optbuf);
83 
84 char *optname[256] =
85 {
86 [OBend]			"end",
87 [OBpad]			"pad",
88 [OBmask]		"mask",
89 [OBtimeoff]		"timeoff",
90 [OBrouter]		"router",
91 [OBtimeserver]		"time",
92 [OBnameserver]		"name",
93 [OBdnserver]		"dns",
94 [OBlogserver]		"log",
95 [OBcookieserver]	"cookie",
96 [OBlprserver]		"lpr",
97 [OBimpressserver]	"impress",
98 [OBrlserver]		"rl",
99 [OBhostname]		"host",
100 [OBbflen]		"bflen",
101 [OBdumpfile]		"dumpfile",
102 [OBdomainname]		"dom",
103 [OBswapserver]		"swap",
104 [OBrootpath]		"rootpath",
105 [OBextpath]		"extpath",
106 [OBipforward]		"ipforward",
107 [OBnonlocal]		"nonlocal",
108 [OBpolicyfilter]	"policyfilter",
109 [OBmaxdatagram]		"maxdatagram",
110 [OBttl]			"ttl",
111 [OBpathtimeout]		"pathtimeout",
112 [OBpathplateau]		"pathplateau",
113 [OBmtu]			"mtu",
114 [OBsubnetslocal]	"subnetslocal",
115 [OBbaddr]		"baddr",
116 [OBdiscovermask]	"discovermask",
117 [OBsupplymask]		"supplymask",
118 [OBdiscoverrouter]	"discoverrouter",
119 [OBrsserver]		"rsserver",
120 [OBstaticroutes]	"staticroutes",
121 [OBtrailerencap]	"trailerencap",
122 [OBarptimeout]		"arptimeout",
123 [OBetherencap]		"etherencap",
124 [OBtcpttl]		"tcpttl",
125 [OBtcpka]		"tcpka",
126 [OBtcpkag]		"tcpkag",
127 [OBnisdomain]		"nisdomain",
128 [OBniserver]		"niserver",
129 [OBntpserver]		"ntpserver",
130 [OBvendorinfo]		"vendorinfo",
131 [OBnetbiosns]		"NBns",
132 [OBnetbiosdds]		"NBdds",
133 [OBnetbiostype]		"NBtype",
134 [OBnetbiosscope]	"NBscope",
135 [OBxfontserver]		"xfont",
136 [OBxdispmanager]	"xdisp",
137 [OBnisplusdomain]	"NPdomain",
138 [OBnisplusserver]	"NP",
139 [OBhomeagent]		"homeagent",
140 [OBsmtpserver]		"smtp",
141 [OBpop3server]		"pop3",
142 [OBnntpserver]		"nntp",
143 [OBwwwserver]		"www",
144 [OBfingerserver]	"finger",
145 [OBircserver]		"ircserver",
146 [OBstserver]		"stserver",
147 [OBstdaserver]		"stdaserver",
148 
149 /* dhcp options */
150 [ODipaddr]		"ip",
151 [ODlease]		"leas",
152 [ODoverload]		"overload",
153 [ODtype]		"typ",
154 [ODserverid]		"sid",
155 [ODparams]		"params",
156 [ODmessage]		"message",
157 [ODmaxmsg]		"maxmsg",
158 [ODrenewaltime]		"renewaltime",
159 [ODrebindingtime]	"rebindingtime",
160 [ODvendorclass]		"vendorclass",
161 [ODclientid]		"cid",
162 [ODtftpserver]		"tftpserver",
163 [ODbootfile]		"bf"
164 };
165 
166 void	addropt(Req*, int, uchar*);
167 void	addrsopt(Req*, int, uchar**, int);
168 void	arpenter(uchar*, uchar*);
169 void	bootp(Req*);
170 void	byteopt(Req*, int, uchar);
171 void	dhcp(Req*);
172 void	fatal(int, char*, ...);
173 void	hexopt(Req*, int, char*);
174 void	longopt(Req*, int, long);
175 void	maskopt(Req*, int, uchar*);
176 void	miscoptions(Req*, uchar*);
177 int	openlisten(char *net);
178 void	parseoptions(Req*);
179 void	proto(Req*, int);
180 void	rcvdecline(Req*);
181 void	rcvdiscover(Req*);
182 void	rcvinform(Req*);
183 void	rcvrelease(Req*);
184 void	rcvrequest(Req*);
185 char*	readsysname(void);
186 void	remrequested(Req*, int);
187 void	sendack(Req*, uchar*, int, int);
188 void	sendnak(Req*, char*);
189 void	sendoffer(Req*, uchar*, int);
190 void	stringopt(Req*, int, char*);
191 void	termopt(Req*);
192 int	validip(uchar*);
193 void	vectoropt(Req*, int, uchar*, int);
194 void	warning(int, char*, ...);
195 void	logdhcp(Req*);
196 void	logdhcpout(Req *, char *);
197 int	readlast(int, Udphdr*, uchar*, int);
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 [-dmsnp] [-f directory] [-x netmtpt] [-M minlease] addr n [addr n ...]\n");
212 	exits("usage");
213 }
214 
215 void
216 main(int argc, char **argv)
217 {
218 	int i, n, fd;
219 	char *p;
220 	uchar ip[IPaddrlen];
221 	Req r;
222 
223 	fmtinstall('E', eipfmt);
224 	fmtinstall('I', eipfmt);
225 	fmtinstall('V', eipfmt);
226 	fmtinstall('M', eipfmt);
227 	ARGBEGIN {
228 	case 'm':
229 		mute = 1;
230 		break;
231 	case 'd':
232 		debug = 1;
233 		break;
234 	case 'f':
235 		p = ARGF();
236 		if(p == nil)
237 			usage();
238 		ndbfile = p;
239 		break;
240 	case 's':
241 		slow = 1;
242 		break;
243 	case 'n':
244 		nobootp = 1;
245 		break;
246 	case 'i':
247 		parseip(xmyipaddr,EARGF(usage()));
248 		break;
249 	case 'p':
250 		pptponly = 1;
251 		break;
252 	case 'M':
253 		p = ARGF();
254 		if(p == nil)
255 			usage();
256 		minlease = atoi(p);
257 		if(minlease <= 0)
258 			minlease = MinLease;
259 		break;
260 	} ARGEND;
261 
262 	while(argc > 1){
263 		parseip(ip, argv[0]);
264 		if(!validip(ip))
265 			usage();
266 		n = atoi(argv[1]);
267 		if(n <= 0)
268 			usage();
269 		initbinding(ip, n);
270 		argc -= 2;
271 		argv += 2;
272 	}
273 
274 	/* for debugging */
275 	for(i = 0; i < 256; i++)
276 		if(optname[i] == 0)
277 			optname[i] = smprint("%d", i);
278 
279 	/* what is my name? */
280 	p = readsysname();
281 	strcpy(mysysname, p);
282 
283 	/* put process in background */
284 	if(!debug) switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
285 	case -1:
286 		fatal(1, "fork");
287 	case 0:
288 		break;
289 	default:
290 		exits(0);
291 	}
292 
293 	chdir(TFTP);
294 	fd = openlisten(net);
295 	wfd = fd;
296 	bwfd = fd;
297 #ifdef SO_BINDTODEVICE
298 	if(setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", 5) < 0)
299 		print("setsockopt: %r\n");
300 #endif
301 
302 	for(;;){
303 		memset(&r, 0, sizeof(r));
304 		r.fd = fd;
305 		n = readlast(fd, &r.uh, r.buf, sizeof(r.buf));
306 		if(n < 0)
307 			fatal(1, "error reading requests");
308 		start = nsec()/1000;
309 		op = optbuf;
310 		*op = 0;
311 		proto(&r, n);
312 		if(r.id != nil)
313 			free(r.id);
314 	}
315 }
316 
317 void
318 proto(Req *rp, int n)
319 {
320 	uchar relip[IPaddrlen];
321 	char buf[64];
322 
323 	now = time(0);
324 
325 	rp->e = rp->buf + n;
326 	rp->bp = (Bootp*)rp->buf;
327 	rp->up = &rp->uh;
328 	rp->max = rp->buf + MINSUPPORTED - IPUDPHDRSIZE;
329 	rp->p = rp->bp->optdata;
330 	v4tov6(rp->giaddr, rp->bp->giaddr);
331 	v4tov6(rp->ciaddr, rp->bp->ciaddr);
332 
333 	if(pptponly && rp->bp->htype != 0)
334 		return;
335 
336 	ipifcs = readipifc(net, ipifcs, -1);
337 	if(validip(rp->giaddr))
338 		ipmove(relip, rp->giaddr);
339 	else if(validip(rp->up->raddr))
340 		ipmove(relip, rp->up->raddr);
341 	else
342 		ipmove(relip, xmyipaddr);
343 	ipmove(rp->up->laddr, xmyipaddr);
344 	if(rp->e < (uchar*)rp->bp->sname){
345 		warning(0, "packet too short");
346 		return;
347 	}
348 	if(rp->bp->op != Bootrequest){
349 		warning(0, "not bootrequest");
350 		return;
351 	}
352 
353 	if(rp->e >= rp->bp->optdata){
354 		if(memcmp(rp->bp->optmagic, plan9opt, sizeof(rp->bp->optmagic)) == 0)
355 			rp->p9request = 1;
356 		if(memcmp(rp->bp->optmagic, genericopt, sizeof(rp->bp->optmagic)) == 0) {
357 			rp->genrequest = 1;
358 			parseoptions(rp);
359 		}
360 	}
361 	rp->p = rp->bp->optdata;
362 
363 	/*  If no id is specified, make one from the hardware address
364 	 *  of the target.  We assume all zeros is not a hardware address
365 	 *  which could be a mistake.
366 	 */
367 	if(rp->id == nil){
368 		if(rp->bp->hlen > Maxhwlen){
369 			warning(0, "hlen %d", rp->bp->hlen);
370 			return;
371 		}
372 		if(memcmp(zeros, rp->bp->chaddr, rp->bp->hlen) == 0){
373 			warning(0, "no chaddr");
374 			return;
375 		}
376 		sprint(buf, "hwa%2.2ux_", rp->bp->htype);
377 		rp->id = tohex(buf, rp->bp->chaddr, rp->bp->hlen);
378 	}
379 
380 	/* info about gateway */
381 	if(lookupip(relip, &rp->gii, 1) < 0){
382 		warning(0, "lookupip failed");
383 		return;
384 	}
385 
386 	/* info about target system */
387 	if(lookup(rp->bp, &rp->ii, &rp->gii) == 0)
388 		if(rp->ii.indb && rp->ii.dhcpgroup[0] == 0)
389 			rp->staticbinding = 1;
390 
391 	if(rp->dhcptype)
392 		dhcp(rp);
393 	else
394 		bootp(rp);
395 timestamp("done");
396 }
397 
398 void
399 dhcp(Req *rp)
400 {
401 	logdhcp(rp);
402 
403 	switch(rp->dhcptype){
404 	case Discover:
405 		if(slow)
406 			sleep(500);
407 		rcvdiscover(rp);
408 		break;
409 	case Request:
410 		rcvrequest(rp);
411 		break;
412 	case Decline:
413 		rcvdecline(rp);
414 		break;
415 	case Release:
416 		rcvrelease(rp);
417 		break;
418 	case Inform:
419 		rcvinform(rp);
420 		break;
421 	}
422 }
423 
424 void
425 rcvdiscover(Req *rp)
426 {
427 	Binding *b, *nb;
428 
429 	if(rp->staticbinding){
430 		sendoffer(rp, rp->ii.ipaddr, StaticLease);
431 		return;
432 	}
433 
434 	/*
435 	 *  first look for an outstanding offer
436 	 */
437 	b = idtooffer(rp->id, &rp->gii);
438 
439 	/*
440 	 * rfc2131 says:
441 	 *   If an address is available, the new address
442 	 *   SHOULD be chosen as follows:
443 	 *
444 	 *      o The client's current address as recorded in the client's current
445 	 *        binding, ELSE
446 	 *
447 	 *      o The client's previous address as recorded in the client's (now
448 	 *        expired or released) binding, if that address is in the server's
449 	 *        pool of available addresses and not already allocated, ELSE
450 	 *
451 	 *      o The address requested in the 'Requested IP Address' option, if that
452 	 *        address is valid and not already allocated, ELSE
453 	 *
454 	 *      o A new address allocated from the server's pool of available
455 	 *        addresses; the address is selected based on the subnet from which
456 	 *        the message was received (if 'giaddr' is 0) or on the address of
457 	 *        the relay agent that forwarded the message ('giaddr' when not 0).
458 	 */
459 	if(b == nil){
460 		b = idtobinding(rp->id, &rp->gii, 1);
461 		if(b && b->boundto && strcmp(b->boundto, rp->id) != 0)
462 		if(validip(rp->ip) && samenet(rp->ip, &rp->gii)){
463 			nb = iptobinding(rp->ip, 0);
464 			if(nb && nb->lease < now)
465 				b = nb;
466 		}
467 	}
468 	if(b == nil){
469 		warning(0, "!Discover(%s via %I): no binding %I",
470 			rp->id, rp->gii.ipaddr, rp->ip);
471 		return;
472 	}
473 	mkoffer(b, rp->id, rp->leasetime);
474 	sendoffer(rp, b->ip, b->offer);
475 }
476 
477 void
478 rcvrequest(Req *rp)
479 {
480 	Binding *b;
481 
482 	if(validip(rp->server)){
483 		/* this is a reply to an offer - SELECTING */
484 
485 		/* check for hard assignment */
486 		if(rp->staticbinding){
487 			if(forme(rp->server))
488 				sendack(rp, rp->ii.ipaddr, StaticLease, 1);
489 			else
490 				warning(0, "!Request(%s via %I): for server %I not me",
491 					rp->id, rp->gii.ipaddr, rp->server);
492 			return;
493 		}
494 
495 		b = idtooffer(rp->id, &rp->gii);
496 
497 		/* if we don't have an offer, nak */
498 		if(b == nil){
499 			warning(0, "!Request(%s via %I): no offer",
500 				rp->id, rp->gii.ipaddr);
501 			if(forme(rp->server))
502 				sendnak(rp, "no offer for you");
503 			return;
504 		}
505 
506 		/* if not for me, retract offer */
507 		if(!forme(rp->server)){
508 			b->expoffer = 0;
509 			warning(0, "!Request(%s via %I): for server %I not me",
510 				rp->id, rp->gii.ipaddr, rp->server);
511 			return;
512 		}
513 
514 		/*
515 		 *  if the client is confused about what we offered, nak.
516 		 *  client really shouldn't be specifying this when selecting
517 		 */
518 		if(validip(rp->ip) && ipcmp(rp->ip, b->ip) != 0){
519 			warning(0, "!Request(%s via %I): requests %I, not %I",
520 				rp->id, rp->gii.ipaddr, rp->ip, b->ip);
521 			sendnak(rp, "bad ip address option");
522 			return;
523 		}
524 		if(commitbinding(b) < 0){
525 			warning(0, "!Request(%s via %I): can't commit %I",
526 				rp->id, rp->gii.ipaddr, b->ip);
527 			sendnak(rp, "can't commit binding");
528 			return;
529 		}
530 		sendack(rp, b->ip, b->offer, 1);
531 	} else if(validip(rp->ip)){
532 		/*
533 		 *  checking address/net - INIT-REBOOT
534 		 *
535 		 *  This is a rebooting client that remembers its old
536 		 *  address.
537 		 */
538 		/* check for hard assignment */
539 		if(rp->staticbinding){
540 			if(memcmp(rp->ip, rp->ii.ipaddr, IPaddrlen) != 0){
541 				warning(0, "!Request(%s via %I): %I not valid for %E",
542 					rp->id, rp->gii.ipaddr, rp->ip, rp->bp->chaddr);
543 				sendnak(rp, "not valid");
544 			}
545 			sendack(rp, rp->ii.ipaddr, StaticLease, 1);
546 			return;
547 		}
548 
549 		/* make sure the network makes sense */
550 		if(!samenet(rp->ip, &rp->gii)){
551 			warning(0, "!Request(%s via %I): bad forward of %I",
552 				rp->id, rp->gii.ipaddr, rp->ip);
553 			sendnak(rp, "wrong network");
554 			return;
555 		}
556 		b = iptobinding(rp->ip, 0);
557 		if(b == nil){
558 			warning(0, "!Request(%s via %I): no binding for %I for",
559 				rp->id, rp->gii.ipaddr, rp->ip);
560 			return;
561 		}
562 		if(memcmp(rp->ip, b->ip, IPaddrlen) != 0 || now > b->lease){
563 			warning(0, "!Request(%s via %I): %I not valid",
564 				rp->id, rp->gii.ipaddr, rp->ip);
565 			sendnak(rp, "not valid");
566 			return;
567 		}
568 		b->offer = b->lease - now;
569 		sendack(rp, b->ip, b->offer, 1);
570 	} else if(validip(rp->ciaddr)){
571 		/*
572 		 *  checking address - RENEWING or REBINDING
573 		 *
574 		 *  these states are indistinguishable in our action.  The only
575 		 *  difference is how close to lease expiration the client is.
576 		 *  If it is really close, it broadcasts the request hoping that
577 		 *  some server will answer.
578 		 */
579 
580 		/* check for hard assignment */
581 		if(rp->staticbinding){
582 			if(ipcmp(rp->ciaddr, rp->ii.ipaddr) != 0){
583 				warning(0, "!Request(%s via %I): %I not valid",
584 					rp->id, rp->gii.ipaddr, rp->ciaddr);
585 				sendnak(rp, "not valid");
586 			}
587 			sendack(rp, rp->ii.ipaddr, StaticLease, 1);
588 			return;
589 		}
590 
591 		/* make sure the network makes sense */
592 		if(!samenet(rp->ciaddr, &rp->gii)){
593 			warning(0, "!Request(%s via %I): bad forward of %I",
594 				rp->id, rp->gii.ipaddr, rp->ip);
595 			sendnak(rp, "wrong network");
596 			return;
597 		}
598 		b = iptobinding(rp->ciaddr, 0);
599 		if(b == nil){
600 			warning(0, "!Request(%s via %I): no binding for %I",
601 				rp->id, rp->gii.ipaddr, rp->ciaddr);
602 			return;
603 		}
604 		if(ipcmp(rp->ciaddr, b->ip) != 0){
605 			warning(0, "!Request(%I via %s): %I not valid",
606 				rp->id, rp->gii.ipaddr, rp->ciaddr);
607 			sendnak(rp, "invalid ip address");
608 			return;
609 		}
610 		mkoffer(b, rp->id, rp->leasetime);
611 		if(commitbinding(b) < 0){
612 			warning(0, "!Request(%s via %I): can't commit %I",
613 				rp->id, rp->gii.ipaddr, b->ip);
614 			sendnak(rp, "can't commit binding");
615 			return;
616 		}
617 		sendack(rp, b->ip, b->offer, 1);
618 	}
619 }
620 
621 void
622 rcvdecline(Req *rp)
623 {
624 	Binding *b;
625 	char buf[64];
626 
627 	if(rp->staticbinding)
628 		return;
629 
630 	b = idtooffer(rp->id, &rp->gii);
631 	if(b == nil){
632 		warning(0, "!Decline(%s via %I): no binding",
633 			rp->id, rp->gii.ipaddr);
634 		return;
635 	}
636 
637 	/* mark ip address as in use */
638 	snprint(buf, sizeof(buf), "declined by %s", rp->id);
639 	mkoffer(b, buf, 0x7fffffff);
640 	commitbinding(b);
641 }
642 
643 void
644 rcvrelease(Req *rp)
645 {
646 	Binding *b;
647 
648 	if(rp->staticbinding)
649 		return;
650 
651 	b = idtobinding(rp->id, &rp->gii, 0);
652 	if(b == nil){
653 		warning(0, "!Release(%s via %I): no binding",
654 			rp->id, rp->gii.ipaddr);
655 		return;
656 	}
657 	if(strcmp(rp->id, b->boundto) != 0){
658 		warning(0, "!Release(%s via %I): invalid release of %I",
659 			rp->id, rp->gii.ipaddr, rp->ip);
660 		return;
661 	}
662 	warning(0, "Release(%s via %I): releasing %I", b->boundto, rp->gii.ipaddr, b->ip);
663 	if(releasebinding(b, rp->id) < 0)
664 		warning(0, "release: couldn't release");
665 }
666 
667 void
668 rcvinform(Req *rp)
669 {
670 	Binding *b;
671 
672 	if(rp->staticbinding){
673 		sendack(rp, rp->ii.ipaddr, 0, 0);
674 		return;
675 	}
676 
677 	b = iptobinding(rp->ciaddr, 0);
678 	if(b == nil){
679 		warning(0, "!Inform(%s via %I): no binding for %I",
680 			rp->id, rp->gii.ipaddr, rp->ip);
681 		return;
682 	}
683 	sendack(rp, b->ip, 0, 0);
684 }
685 
686 int
687 setsiaddr(uchar *siaddr, uchar *saddr, uchar *laddr)
688 {
689 	if(ipcmp(saddr, IPnoaddr) != 0){
690 		v6tov4(siaddr, saddr);
691 		return 0;
692 	} else {
693 		v6tov4(siaddr, laddr);
694 		return 1;
695 	}
696 }
697 
698 void
699 sendoffer(Req *rp, uchar *ip, int offer)
700 {
701 	int n;
702 	int fd;
703 	ushort flags;
704 	Bootp *bp;
705 	Udphdr *up;
706 
707 	bp = rp->bp;
708 	up = rp->up;
709 
710 	/*
711 	 *  set destination
712 	 */
713 	flags = nhgets(bp->flags);
714 	fd = wfd;
715 	if(validip(rp->giaddr)){
716 		ipmove(up->raddr, rp->giaddr);
717 		hnputs(up->rport, 67);
718 	} else if(flags & Fbroadcast){
719 		fd = bwfd;
720 		ipmove(up->raddr, IPv4bcast);
721 		hnputs(up->rport, 68);
722 	} else {
723 		ipmove(up->raddr, ip);
724 		if(bp->htype == 1)
725 			arpenter(up->raddr, bp->chaddr);
726 		hnputs(up->rport, 68);
727 	}
728 
729 	/*
730 	 *  fill in standard bootp part
731 	 */
732 	bp->op = Bootreply;
733 	bp->hops = 0;
734 	hnputs(bp->secs, 0);
735 	memset(bp->ciaddr, 0, sizeof(bp->ciaddr));
736 	v6tov4(bp->giaddr, rp->giaddr);
737 	v6tov4(bp->yiaddr, ip);
738 	setsiaddr(bp->siaddr, rp->ii.tftp, up->laddr);
739 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
740 	strncpy(bp->file, rp->ii.bootf, sizeof(bp->file));
741 
742 	/*
743 	 *  set options
744 	 */
745 	byteopt(rp, ODtype, Offer);
746 	longopt(rp, ODlease, offer);
747 	addropt(rp, ODserverid, up->laddr);
748 	miscoptions(rp, ip);
749 	termopt(rp);
750 
751 	logdhcpout(rp, "Offer");
752 
753 	/*
754 	 *  send
755 	 */
756 	n = rp->p - rp->buf;
757 	if(!mute && udpwrite(fd, rp->up, rp->buf, n) != n)
758 		warning(0, "offer: write failed: %r");
759 }
760 
761 void
762 sendack(Req *rp, uchar *ip, int offer, int sendlease)
763 {
764 	int n, fd;
765 	ushort flags;
766 	Bootp *bp;
767 	Udphdr *up;
768 
769 	bp = rp->bp;
770 	up = rp->up;
771 
772 	/*
773 	 *  set destination
774 	 */
775 	fd = wfd;
776 	flags = nhgets(bp->flags);
777 	if(validip(rp->giaddr)){
778 		ipmove(up->raddr, rp->giaddr);
779 		hnputs(up->rport, 67);
780 	} else if(flags & Fbroadcast){
781 		fd = bwfd;
782 		ipmove(up->raddr, IPv4bcast);
783 		hnputs(up->rport, 68);
784 	} else {
785 		ipmove(up->raddr, ip);
786 		if(bp->htype == 1)
787 			arpenter(up->raddr, bp->chaddr);
788 		hnputs(up->rport, 68);
789 	}
790 
791 	/*
792 	 *  fill in standard bootp part
793 	 */
794 	bp->op = Bootreply;
795 	bp->hops = 0;
796 	hnputs(bp->secs, 0);
797 	v6tov4(bp->giaddr, rp->giaddr);
798 	v6tov4(bp->yiaddr, ip);
799 	setsiaddr(bp->siaddr, rp->ii.tftp, up->laddr);
800 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
801 	strncpy(bp->file, rp->ii.bootf, sizeof(bp->file));
802 
803 	/*
804 	 *  set options
805 	 */
806 	byteopt(rp, ODtype, Ack);
807 	if(sendlease){
808 		longopt(rp, ODlease, offer);
809 	}
810 	addropt(rp, ODserverid, up->laddr);
811 	miscoptions(rp, ip);
812 	termopt(rp);
813 
814 	logdhcpout(rp, "Ack");
815 
816 	/*
817 	 *  send
818 	 */
819 	n = rp->p - rp->buf;
820 	if(!mute && udpwrite(fd, rp->up, rp->buf, n) != n)
821 		warning(0, "ack: write failed: %r");
822 }
823 
824 void
825 sendnak(Req *rp, char *msg)
826 {
827 	int n, fd;
828 	Bootp *bp;
829 	Udphdr *up;
830 
831 	bp = rp->bp;
832 	up = rp->up;
833 
834 	/*
835 	 *  set destination (always broadcast)
836 	 */
837 	fd = wfd;
838 	if(validip(rp->giaddr)){
839 		ipmove(up->raddr, rp->giaddr);
840 		hnputs(up->rport, 67);
841 	} else {
842 		fd = bwfd;
843 		ipmove(up->raddr, IPv4bcast);
844 		hnputs(up->rport, 68);
845 	}
846 
847 	/*
848 	 *  fill in standard bootp part
849 	 */
850 	bp->op = Bootreply;
851 	bp->hops = 0;
852 	hnputs(bp->secs, 0);
853 	v6tov4(bp->giaddr, rp->giaddr);
854 	memset(bp->ciaddr, 0, sizeof(bp->ciaddr));
855 	memset(bp->yiaddr, 0, sizeof(bp->yiaddr));
856 	memset(bp->siaddr, 0, sizeof(bp->siaddr));
857 
858 	/*
859 	 *  set options
860 	 */
861 	byteopt(rp, ODtype, Nak);
862 	addropt(rp, ODserverid, up->laddr);
863 	if(msg)
864 		stringopt(rp, ODmessage, msg);
865 	if(strncmp(rp->id, "id", 2) == 0)
866 		hexopt(rp, ODclientid, rp->id+2);
867 	termopt(rp);
868 
869 	logdhcpout(rp, "Nak");
870 
871 	/*
872 	 *  send nak
873 	 */
874 	n = rp->p - rp->buf;
875 	if(!mute && udpwrite(fd, rp->up, rp->buf, n) != n)
876 		warning(0, "nak: write failed: %r");
877 }
878 
879 void
880 bootp(Req *rp)
881 {
882 	int n, fd;
883 	Bootp *bp;
884 	Udphdr *up;
885 	ushort flags;
886 	Iplifc *lifc;
887 	Info *iip;
888 
889 	warning(0, "bootp %s %I->%I from %s via %I, file %s",
890 		rp->genrequest ? "generic" : (rp->p9request ? "p9" : ""),
891 		rp->up->raddr, rp->up->laddr,
892 		rp->id, rp->gii.ipaddr,
893 		rp->bp->file);
894 
895 	if(nobootp)
896 		return;
897 
898 	bp = rp->bp;
899 	up = rp->up;
900 	iip = &rp->ii;
901 
902 	if(rp->staticbinding == 0){
903 		warning(0, "bootp from unknown %s via %I", rp->id, rp->gii.ipaddr);
904 		return;
905 	}
906 
907 	/* ignore if not for us */
908 	if(*bp->sname){
909 		if(strcmp(bp->sname, mysysname) != 0){
910 			bp->sname[20] = 0;
911 			warning(0, "bootp for server %s", bp->sname);
912 			return;
913 		}
914 	} else if(slow)
915 		sleep(500);
916 
917 	/* ignore if we don't know what file to load */
918 	if(*bp->file == 0){
919 		if(rp->genrequest && *iip->bootf2)	/* if not plan 9 and we have an alternate file... */
920 			strncpy(bp->file, iip->bootf2, sizeof(bp->file));
921 		else if(*iip->bootf)
922 			strncpy(bp->file, iip->bootf, sizeof(bp->file));
923 		else if(*bp->sname)		/* if we were asked, respond no matter what */
924 			bp->file[0] = '\0';
925 		else {
926 			warning(0, "no bootfile for %I", iip->ipaddr);
927 			return;
928 		}
929 	}
930 
931 	/* ignore if the file is unreadable */
932 	if((!rp->genrequest) && bp->file[0] && access(bp->file, 4) < 0){
933 		warning(0, "inaccessible bootfile1 %s", bp->file);
934 		return;
935 	}
936 
937 	bp->op = Bootreply;
938 	v6tov4(bp->yiaddr, iip->ipaddr);
939 	if(rp->p9request){
940 		warning(0, "p9bootp: %I", iip->ipaddr);
941 		memmove(bp->optmagic, plan9opt, 4);
942 		if(iip->gwip == 0)
943 			v4tov6(iip->gwip, bp->giaddr);
944 		rp->p += sprint((char*)rp->p, "%V %I %I %I", iip->ipmask+IPv4off, iip->fsip,
945 				iip->auip, iip->gwip);
946 		sprint(optbuf, "%s", (char*)(bp->optmagic));
947 	} else if(rp->genrequest){
948 		warning(0, "genericbootp: %I", iip->ipaddr);
949 		memmove(bp->optmagic, genericopt, 4);
950 		miscoptions(rp, iip->ipaddr);
951 		termopt(rp);
952 	} else if(iip->vendor[0] != 0) {
953 		warning(0, "bootp vendor field: %s", iip->vendor);
954 		memset(rp->p, 0, 128-4);
955 		rp->p += sprint((char*)bp->optmagic, "%s", iip->vendor);
956 	} else {
957 		memset(rp->p, 0, 128-4);
958 		rp->p += 128-4;
959 	}
960 
961 	/*
962 	 *  set destination
963 	 */
964 	fd = wfd;
965 	flags = nhgets(bp->flags);
966 	if(validip(rp->giaddr)){
967 		ipmove(up->raddr, rp->giaddr);
968 		hnputs(up->rport, 67);
969 	} else if(flags & Fbroadcast){
970 		fd = bwfd;
971 		ipmove(up->raddr, IPv4bcast);
972 		hnputs(up->rport, 68);
973 	} else {
974 		v4tov6(up->raddr, bp->yiaddr);
975 		if(bp->htype == 1)
976 			arpenter(up->raddr, bp->chaddr);
977 		hnputs(up->rport, 68);
978 	}
979 
980 	/*
981 	 *  select best local address if destination is directly connected
982 	 */
983 	lifc = findlifc(up->raddr);
984 	if(lifc)
985 		ipmove(up->laddr, lifc->ip);
986 
987 	/*
988 	 *  our identity
989 	 */
990 	strncpy(bp->sname, mysysname, sizeof(bp->sname));
991 
992 	/*
993 	 *  set tftp server
994 	 */
995 	setsiaddr(bp->siaddr, iip->tftp, up->laddr);
996 	if(rp->genrequest && *iip->bootf2)
997 		setsiaddr(bp->siaddr, iip->tftp2, up->laddr);
998 
999 	/*
1000 	 * RFC 1048 says that we must pad vendor field with
1001 	 * zeros until we have a 64 byte field.
1002 	 */
1003 	n = rp->p - rp->bp->optdata;
1004 	if(n < 64-4) {
1005 		memset(rp->p, 0, (64-4)-n);
1006 		rp->p += (64-4)-n;
1007 	}
1008 
1009 	/*
1010 	 *  send
1011 	 */
1012 	n = rp->p - rp->buf;
1013 	if(!mute && udpwrite(fd, rp->up, rp->buf, n) != n)
1014 		warning(0, "bootp: write failed: %r");
1015 
1016 	warning(0, "bootp via %I: file %s xid(%ux)flag(%ux)ci(%V)gi(%V)yi(%V)si(%V) %s",
1017 			up->raddr, bp->file, nhgetl(bp->xid), nhgets(bp->flags),
1018 			bp->ciaddr, bp->giaddr, bp->yiaddr, bp->siaddr,
1019 			optbuf);
1020 }
1021 
1022 void
1023 parseoptions(Req *rp)
1024 {
1025 	int n, c, code;
1026 	uchar *o, *p;
1027 
1028 	p = rp->p;
1029 
1030 	while(p < rp->e){
1031 		code = *p++;
1032 		if(code == 255)
1033 			break;
1034 		if(code == 0)
1035 			continue;
1036 
1037 		/* ignore anything that's too long */
1038 		n = *p++;
1039 		o = p;
1040 		p += n;
1041 		if(p > rp->e)
1042 			return;
1043 
1044 		switch(code){
1045 		case ODipaddr:	/* requested ip address */
1046 			if(n == IPv4addrlen)
1047 				v4tov6(rp->ip, o);
1048 			break;
1049 		case ODlease:	/* requested lease time */
1050 			rp->leasetime = nhgetl(o);
1051 			if(rp->leasetime > MaxLease || rp->leasetime < 0)
1052 				rp->leasetime = MaxLease;
1053 			break;
1054 		case ODtype:
1055 			c = *o;
1056 			if(c < 10 && c > 0)
1057 				rp->dhcptype = c;
1058 			break;
1059 		case ODserverid:
1060 			if(n == IPv4addrlen)
1061 				v4tov6(rp->server, o);
1062 			break;
1063 		case ODmessage:
1064 			if(n > sizeof rp->msg-1)
1065 				n = sizeof rp->msg-1;
1066 			memmove(rp->msg, o, n);
1067 			rp->msg[n] = 0;
1068 			break;
1069 		case ODmaxmsg:
1070 			c = nhgets(o);
1071 			c -= 28;
1072 			if(c > 0)
1073 				rp->max = rp->buf + c;
1074 			break;
1075 		case ODclientid:
1076 			if(n <= 1)
1077 				break;
1078 			rp->id = toid( o, n);
1079 			break;
1080 		case ODparams:
1081 			if(n > sizeof(rp->requested))
1082 				n = sizeof(rp->requested);
1083 			memmove(rp->requested, o, n);
1084 			break;
1085 		case ODvendorclass:
1086 			if(n >= sizeof(rp->vendorclass))
1087 				n = sizeof(rp->vendorclass)-1;
1088 			memmove(rp->vendorclass, o, n);
1089 			rp->vendorclass[n] = 0;
1090 			if(strncmp((char*)rp->vendorclass, "p9-", 3) == 0)
1091 				strcpy(rp->cputype, (char*)rp->vendorclass+3);
1092 			break;
1093 		case OBend:
1094 			return;
1095 		}
1096 	}
1097 }
1098 
1099 void
1100 remrequested(Req *rp, int opt)
1101 {
1102 	uchar *p;
1103 
1104 	p = memchr(rp->requested, opt, sizeof(rp->requested));
1105 	if(p != nil)
1106 		*p = OBpad;
1107 }
1108 
1109 void
1110 miscoptions(Req *rp, uchar *ip)
1111 {
1112 	char *p;
1113 	int i, j;
1114 	uchar *addrs[2];
1115 	uchar x[2*IPaddrlen];
1116 	uchar vopts[64];
1117 	uchar *op, *omax;
1118 	char *attr[100], **a;
1119 	int na;
1120 	Ndbtuple *t;
1121 
1122 	addrs[0] = x;
1123 	addrs[1] = x+IPaddrlen;
1124 
1125 	/* always supply these */
1126 	maskopt(rp, OBmask, rp->gii.ipmask);
1127 	if(validip(rp->gii.gwip)){
1128 		remrequested(rp, OBrouter);
1129 		addropt(rp, OBrouter, rp->gii.gwip);
1130 	} else if(validip(rp->giaddr)){
1131 		remrequested(rp, OBrouter);
1132 		addropt(rp, OBrouter, rp->giaddr);
1133 	}
1134 
1135 	/* OBhostname for the HP4000M switches */
1136 	/* (this causes NT to log infinite errors - tough shit ) */
1137 	if(*rp->ii.domain){
1138 		remrequested(rp, OBhostname);
1139 		stringopt(rp, OBhostname, rp->ii.domain);
1140 	}
1141 	if(*rp->ii.rootpath)
1142 		stringopt(rp, OBrootpath, rp->ii.rootpath);
1143 
1144 	/* figure out what we need to lookup */
1145 	na = 0;
1146 	a = attr;
1147 	if(*rp->ii.domain == 0)
1148 		a[na++] = "dom";
1149 	for(i = 0; i < sizeof(rp->requested); i++)
1150 		switch(rp->requested[i]){
1151 		case OBrouter:
1152 			a[na++] = "@ipgw";
1153 			break;
1154 		case OBdnserver:
1155 			a[na++] = "@dns";
1156 			break;
1157 		case OBnetbiosns:
1158 			a[na++] = "@wins";
1159 			break;
1160 		case OBsmtpserver:
1161 			a[na++] = "@smtp";
1162 			break;
1163 		case OBpop3server:
1164 			a[na++] = "@pop3";
1165 			break;
1166 		case OBwwwserver:
1167 			a[na++] = "@www";
1168 			break;
1169 		case OBntpserver:
1170 			a[na++] = "@ntp";
1171 			break;
1172 		case OBtimeserver:
1173 			a[na++] = "@time";
1174 			break;
1175 		}
1176 	if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0
1177 	|| strncmp((char*)rp->vendorclass, "p9-", 3) == 0){
1178 		a[na++] = "@fs";
1179 		a[na++] = "@auth";
1180 	}
1181 	t = lookupinfo(ip, a, na);
1182 
1183 	/* lookup anything we might be missing */
1184 	if(*rp->ii.domain == 0)
1185 		lookupname(rp->ii.domain, t);
1186 
1187 	/* add any requested ones that we know about */
1188 	for(i = 0; i < sizeof(rp->requested); i++)
1189 		switch(rp->requested[i]){
1190 		case OBrouter:
1191 			j = lookupserver("ipgw", addrs, t);
1192 			addrsopt(rp, OBrouter, addrs, j);
1193 			break;
1194 		case OBdnserver:
1195 			j = lookupserver("dns", addrs, t);
1196 			addrsopt(rp, OBdnserver, addrs, j);
1197 			break;
1198 		case OBhostname:
1199 			if(*rp->ii.domain)
1200 				stringopt(rp, OBhostname, rp->ii.domain);
1201 			break;
1202 		case OBdomainname:
1203 			p = strchr(rp->ii.domain, '.');
1204 			if(p)
1205 				stringopt(rp, OBdomainname, p+1);
1206 			break;
1207 		case OBnetbiosns:
1208 			j = lookupserver("wins", addrs, t);
1209 			addrsopt(rp, OBnetbiosns, addrs, j);
1210 			break;
1211 		case OBnetbiostype:
1212 			/* p-node: peer to peer WINS queries */
1213 			byteopt(rp, OBnetbiostype, 0x2);
1214 			break;
1215 		case OBsmtpserver:
1216 			j = lookupserver("smtp", addrs, t);
1217 			addrsopt(rp, OBsmtpserver, addrs, j);
1218 			break;
1219 		case OBpop3server:
1220 			j = lookupserver("pop3", addrs, t);
1221 			addrsopt(rp, OBpop3server, addrs, j);
1222 			break;
1223 		case OBwwwserver:
1224 			j = lookupserver("www", addrs, t);
1225 			addrsopt(rp, OBwwwserver, addrs, j);
1226 			break;
1227 		case OBntpserver:
1228 			j = lookupserver("ntp", addrs, t);
1229 			addrsopt(rp, OBntpserver, addrs, j);
1230 			break;
1231 		case OBtimeserver:
1232 			j = lookupserver("time", addrs, t);
1233 			addrsopt(rp, OBtimeserver, addrs, j);
1234 			break;
1235 		case OBttl:
1236 			byteopt(rp, OBttl, 255);
1237 			break;
1238 		}
1239 
1240 	/* add plan9 specific options */
1241 	if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0
1242 	|| strncmp((char*)rp->vendorclass, "p9-", 3) == 0){
1243 		/* point to temporary area */
1244 		op = rp->p;
1245 		omax = rp->max;
1246 		rp->p = vopts;
1247 		rp->max = vopts + sizeof(vopts) - 1;
1248 
1249 		j = lookupserver("fs", addrs, t);
1250 		addrsopt(rp, OP9fs, addrs, j);
1251 		j = lookupserver("auth", addrs, t);
1252 		addrsopt(rp, OP9auth, addrs, j);
1253 
1254 		/* point back */
1255 		j = rp->p - vopts;
1256 		rp->p = op;
1257 		rp->max = omax;
1258 		vectoropt(rp, OBvendorinfo, vopts, j);
1259 	}
1260 
1261 	ndbfree(t);
1262 }
1263 
1264 int
1265 openlisten(char *net)
1266 {
1267 	int fd;
1268 	char data[128];
1269 	char devdir[40];
1270 	int yes;
1271 
1272 	sprint(data, "udp!*!bootps");
1273 	fd = announce(data, devdir);
1274 	if(fd < 0)
1275 		fatal(1, "can't announce");
1276 	yes = 1;
1277 	if(setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &yes, sizeof yes) < 0)
1278 		fatal(1, "can't broadcast");
1279 	return fd;
1280 }
1281 
1282 void
1283 fatal(int syserr, char *fmt, ...)
1284 {
1285 	char buf[ERRMAX];
1286 	va_list arg;
1287 
1288 	va_start(arg, fmt);
1289 	vseprint(buf, buf+sizeof(buf), fmt, arg);
1290 	va_end(arg);
1291 	if(syserr)
1292 		syslog(1, blog, "%s: %r", buf);
1293 	else
1294 		syslog(1, blog, "%s", buf);
1295 	exits(buf);
1296 }
1297 
1298 extern void
1299 warning(int syserr, char *fmt, ...)
1300 {
1301 	char buf[256];
1302 	va_list arg;
1303 
1304 	va_start(arg, fmt);
1305 	vseprint(buf, buf+sizeof(buf), fmt, arg);
1306 	va_end(arg);
1307 	if(syserr){
1308 		syslog(0, blog, "%s: %r", buf);
1309 		if(debug)
1310 			fprint(2, "%s: %r\n", buf);
1311 	} else {
1312 		syslog(0, blog, "%s", buf);
1313 		if(debug)
1314 			fprint(2, "%s\n", buf);
1315 	}
1316 }
1317 
1318 char*
1319 readsysname(void)
1320 {
1321 	static char name[128];
1322 	char *p;
1323 	int n, fd;
1324 
1325 	fd = open("/dev/sysname", OREAD);
1326 	if(fd >= 0){
1327 		n = read(fd, name, sizeof(name)-1);
1328 		close(fd);
1329 		if(n > 0){
1330 			name[n] = 0;
1331 			return name;
1332 		}
1333 	}
1334 	p = getenv("sysname");
1335 	if(p == nil || *p == 0)
1336 		return "unknown";
1337 	return p;
1338 }
1339 
1340 extern int
1341 validip(uchar *ip)
1342 {
1343 	if(ipcmp(ip, IPnoaddr) == 0)
1344 		return 0;
1345 	if(ipcmp(ip, v4prefix) == 0)
1346 		return 0;
1347 	return 1;
1348 }
1349 
1350 void
1351 longopt(Req *rp, int t, long v)
1352 {
1353 	if(rp->p + 6 > rp->max)
1354 		return;
1355 	*rp->p++ = t;
1356 	*rp->p++ = 4;
1357 	hnputl(rp->p, v);
1358 	rp->p += 4;
1359 
1360 	op = seprint(op, oe, "%s(%ld)", optname[t], v);
1361 }
1362 
1363 void
1364 addropt(Req *rp, int t, uchar *ip)
1365 {
1366 	if(rp->p + 6 > rp->max)
1367 		return;
1368 	*rp->p++ = t;
1369 	*rp->p++ = 4;
1370 	memmove(rp->p, ip+IPv4off, 4);
1371 	rp->p += 4;
1372 
1373 	op = seprint(op, oe, "%s(%I)", optname[t], ip);
1374 }
1375 
1376 void
1377 maskopt(Req *rp, int t, uchar *ip)
1378 {
1379 	if(rp->p + 6 > rp->max)
1380 		return;
1381 	*rp->p++ = t;
1382 	*rp->p++ = 4;
1383 	memmove(rp->p, ip+IPv4off, 4);
1384 	rp->p += 4;
1385 
1386 	op = seprint(op, oe, "%s(%M)", optname[t], ip);
1387 }
1388 
1389 void
1390 addrsopt(Req *rp, int t, uchar **ip, int i)
1391 {
1392 	if(i <= 0)
1393 		return;
1394 	if(rp->p + 2 + 4*i > rp->max)
1395 		return;
1396 	*rp->p++ = t;
1397 	*rp->p++ = 4*i;
1398 	op = seprint(op, oe, "%s(", optname[t]);
1399 	while(i-- > 0){
1400 		v6tov4(rp->p, *ip);
1401 		rp->p += 4;
1402 		op = seprint(op, oe, "%I", *ip);
1403 		ip++;
1404 		if(i > 0)
1405 			op = seprint(op, oe, " ");
1406 	}
1407 	op = seprint(op, oe, ")");
1408 }
1409 
1410 void
1411 byteopt(Req *rp, int t, uchar v)
1412 {
1413 	if(rp->p + 3 > rp->max)
1414 		return;
1415 	*rp->p++ = t;
1416 	*rp->p++ = 1;
1417 	*rp->p++ = v;
1418 
1419 	op = seprint(op, oe, "%s(%d)", optname[t], v);
1420 }
1421 
1422 void
1423 termopt(Req *rp)
1424 {
1425 	if(rp->p + 1 > rp->max)
1426 		return;
1427 	*rp->p++ = OBend;
1428 }
1429 
1430 void
1431 stringopt(Req *rp, int t, char *str)
1432 {
1433 	int n;
1434 
1435 	n = strlen(str);
1436 	if(n > 255)
1437 		n = 255;
1438 	if(rp->p+n+2 > rp->max)
1439 		return;
1440 	*rp->p++ = t;
1441 	*rp->p++ = n;
1442 	memmove(rp->p, str, n);
1443 	rp->p += n;
1444 
1445 	op = seprint(op, oe, "%s(%s)", optname[t], str);
1446 }
1447 
1448 void
1449 vectoropt(Req *rp, int t, uchar *v, int n)
1450 {
1451 	int i;
1452 
1453 	if(n > 255)
1454 		n = 255;
1455 	if(rp->p+n+2 > rp->max)
1456 		return;
1457 	*rp->p++ = t;
1458 	*rp->p++ = n;
1459 	memmove(rp->p, v, n);
1460 	rp->p += n;
1461 
1462 	op = seprint(op, oe, "%s(", optname[t]);
1463 	if(n > 0)
1464 		op = seprint(op, oe, "%ud", 0);
1465 	for(i = 1; i < n; i++)
1466 		op = seprint(op, oe, " %ud", v[i]);
1467 }
1468 
1469 int
1470 fromhex(int x)
1471 {
1472 	if(x >= '0' && x <= '9')
1473 		return x - '0';
1474 	return x - 'a';
1475 }
1476 
1477 void
1478 hexopt(Req *rp, int t, char *str)
1479 {
1480 	int n;
1481 
1482 	n = strlen(str);
1483 	n /= 2;
1484 	if(n > 255)
1485 		n = 255;
1486 	if(rp->p+n+2 > rp->max)
1487 		return;
1488 	*rp->p++ = t;
1489 	*rp->p++ = n;
1490 	while(n-- > 0){
1491 		*rp->p++ = (fromhex(str[0])<<4)|fromhex(str[1]);
1492 		str += 2;
1493 	}
1494 
1495 	op = seprint(op, oe, "%s(%s)", optname[t], str);
1496 }
1497 
1498 /*
1499  * What a crock it is to do this for real.
1500  * A giant hairy mess of ioctls that differ from
1501  * system to system.  Don't get sucked in.
1502  * This need not be fast.
1503  */
1504 void
1505 arpenter(uchar *ip, uchar *ether)
1506 {
1507 	int pid;
1508 	char xip[100], xether[100];
1509 
1510 	switch(pid=fork()){
1511 	case -1:
1512 		break;
1513 	default:
1514 		waitpid();
1515 		break;
1516 	case 0:
1517 		snprint(xip, sizeof xip, "%I", ip);
1518 		snprint(xether, sizeof xether, "%#E", ether);
1519 		execl("arp", "arp", "-s", xip, xether, "temp", nil);
1520 		_exits("execl");
1521 	}
1522 /*
1523 	for comfort - ah, the good old days
1524 
1525 	int f;
1526 	char buf[256];
1527 
1528 	sprint(buf, "%s/arp", net);
1529 	f = open(buf, OWRITE);
1530 	if(f < 0){
1531 		syslog(debug, blog, "open %s: %r", buf);
1532 		return;
1533 	}
1534 	fprint(f, "add ether %I %E", ip, ether);
1535 	close(f);
1536 */
1537 }
1538 
1539 char *dhcpmsgname[] =
1540 {
1541 	[Discover]	"Discover",
1542 	[Offer]		"Offer",
1543 	[Request]	"Request",
1544 	[Decline]	"Decline",
1545 	[Ack]		"Ack",
1546 	[Nak]		"Nak",
1547 	[Release]	"Release",
1548 	[Inform]	"Inform"
1549 };
1550 
1551 void
1552 logdhcp(Req *rp)
1553 {
1554 	char buf[4096];
1555 	char *p, *e;
1556 	int i;
1557 
1558 	p = buf;
1559 	e = buf + sizeof(buf);
1560 	if(rp->dhcptype > 0 && rp->dhcptype <= Inform)
1561 		p = seprint(p, e, "%s(", dhcpmsgname[rp->dhcptype]);
1562 	else
1563 		p = seprint(p, e, "%d(", rp->dhcptype);
1564 	p = seprint(p, e, "%I->%I) xid(%ux)flag(%ux)", rp->up->raddr, rp->up->laddr,
1565 		nhgetl(rp->bp->xid), nhgets(rp->bp->flags));
1566 	if(rp->bp->htype == 1)
1567 		p = seprint(p, e, "ea(%E)", rp->bp->chaddr);
1568 	if(validip(rp->ciaddr))
1569 		p = seprint(p, e, "ci(%I)", rp->ciaddr);
1570 	if(validip(rp->giaddr))
1571 		p = seprint(p, e, "gi(%I)", rp->giaddr);
1572 	if(validip(rp->ip))
1573 		p = seprint(p, e, "ip(%I)", rp->ip);
1574 	if(rp->id != nil)
1575 		p = seprint(p, e, "id(%s)", rp->id);
1576 	if(rp->leasetime)
1577 		p = seprint(p, e, "leas(%d)", rp->leasetime);
1578 	if(validip(rp->server))
1579 		p = seprint(p, e, "sid(%I)", rp->server);
1580 	p = seprint(p, e, "need(");
1581 	for(i = 0; i < sizeof(rp->requested); i++)
1582 		if(rp->requested[i] != 0)
1583 			p = seprint(p, e, "%s ", optname[rp->requested[i]]);
1584 	p = seprint(p, e, ")");
1585 
1586 	USED(p);
1587 	syslog(0, blog, "%s", buf);
1588 }
1589 
1590 void
1591 logdhcpout(Req *rp, char *type)
1592 {
1593 	syslog(0, blog, "%s(%I->%I)id(%s)ci(%V)gi(%V)yi(%V)si(%V) %s",
1594 		type, rp->up->laddr, rp->up->raddr, rp->id,
1595 		rp->bp->ciaddr, rp->bp->giaddr, rp->bp->yiaddr, rp->bp->siaddr, optbuf);
1596 }
1597 
1598 /*
1599  *  if we get behind, it's useless to try answering since the sender
1600  *  will probably have retransmitted with a differnt sequence number.
1601  *  So dump all the last message in the queue.
1602  */
1603 void ding(void *x, char *msg)
1604 {
1605 	USED(x);
1606 
1607 	if(strstr(msg, "alarm"))
1608 		noted(NCONT);
1609 	else
1610 		noted(NDFLT);
1611 }
1612 
1613 int
1614 readlast(int fd, Udphdr *hdr, uchar *buf, int len)
1615 {
1616 	int lastn, n;
1617 
1618 	notify(ding);
1619 
1620 	lastn = 0;
1621 	for(;;){
1622 		alarm(20);
1623 		n = udpread(fd, hdr, buf, len);
1624 		alarm(0);
1625 		if(n < 0){
1626 			if(lastn > 0)
1627 				return lastn;
1628 			break;
1629 		}
1630 		lastn = n;
1631 	}
1632 	return udpread(fd, hdr, buf, len);
1633 }