plan9port

fork of plan9port with libvec, libstr and libsdb
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dhcpd.c (33602B)


      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 }