Import sources from 2011-03-30 iso image

1 files changed, 1689 insertions, 0 deletions

diff --git a/sys/src/cmd/ip/dhcpd/dhcpd.c b/sys/src/cmd/ip/dhcpd/dhcpd.c
new file mode 100755
index 000000000..885c14164
--- /dev/null
+++ b/sys/src/cmd/ip/dhcpd/dhcpd.c
@@ -0,0 +1,1689 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include <bio.h>
+#include <ndb.h>
+#include "dat.h"
+
+/*
+ *	ala rfc2131
+ */
+
+enum {
+	Maxloglen = 1024,
+};
+
+typedef struct Req Req;
+struct Req
+{
+	int	fd;			/* for reply */
+	Bootp	*bp;
+	Udphdr	*up;
+	uchar	*e;			/* end of received message */
+	uchar	*p;			/* options pointer */
+	uchar	*max;			/* max end of reply */
+
+	/* expanded to v6 */
+	uchar	ciaddr[IPaddrlen];
+	uchar	giaddr[IPaddrlen];
+
+	/* parsed options */
+	int	p9request;		/* flag: this is a bootp with plan9 options */
+	int	genrequest;		/* flag: this is a bootp with generic options */
+	int	dhcptype;		/* dhcp message type */
+	int	leasetime;		/* dhcp lease */
+	uchar	ip[IPaddrlen];		/* requested address */
+	uchar	server[IPaddrlen];	/* server address */
+	char	msg[ERRMAX];		/* error message */
+	char	vci[32];		/* vendor class id */
+	char	*id;			/* client id */
+	uchar	requested[32];		/* requested params */
+	uchar	vendorclass[32];
+	char	cputype[32-3];
+
+	Info	gii;			/* about target network */
+	Info	ii;			/* about target system */
+	int	staticbinding;
+
+	uchar buf[2*1024];		/* message buffer */
+};
+
+#define TFTP "/lib/tftpd"
+
+char	*blog = "ipboot";
+char	mysysname[64];
+Ipifc	*ipifcs;
+int	debug;
+int	nobootp;
+long	now;
+int	slowstat, slowdyn;
+char	net[256];
+
+int	pptponly;	/* only answer request that came from the pptp server */
+int	mute, mutestat;
+int	minlease = MinLease;
+int	staticlease = StaticLease;
+
+uvlong	start;
+
+static int v6opts;
+
+/* option magic */
+char plan9opt[4] = { 'p', '9', ' ', ' ' };
+char genericopt[4] = { 0x63, 0x82, 0x53, 0x63 };
+
+/* well known addresses */
+uchar zeros[Maxhwlen];
+
+/* option debug buffer */
+char optbuf[1024];
+char *op;
+char *oe = optbuf + sizeof(optbuf);
+
+char *optname[256] =
+{
+[OBend]			"end",
+[OBpad]			"pad",
+[OBmask]		"mask",
+[OBtimeoff]		"timeoff",
+[OBrouter]		"router",
+[OBtimeserver]		"time",
+[OBnameserver]		"name",
+[OBdnserver]		"dns",
+[OBlogserver]		"log",
+[OBcookieserver]	"cookie",
+[OBlprserver]		"lpr",
+[OBimpressserver]	"impress",
+[OBrlserver]		"rl",
+[OBhostname]		"host",
+[OBbflen]		"bflen",
+[OBdumpfile]		"dumpfile",
+[OBdomainname]		"dom",
+[OBswapserver]		"swap",
+[OBrootpath]		"rootpath",
+[OBextpath]		"extpath",
+[OBipforward]		"ipforward",
+[OBnonlocal]		"nonlocal",
+[OBpolicyfilter]	"policyfilter",
+[OBmaxdatagram]		"maxdatagram",
+[OBttl]			"ttl",
+[OBpathtimeout]		"pathtimeout",
+[OBpathplateau]		"pathplateau",
+[OBmtu]			"mtu",
+[OBsubnetslocal]	"subnetslocal",
+[OBbaddr]		"baddr",
+[OBdiscovermask]	"discovermask",
+[OBsupplymask]		"supplymask",
+[OBdiscoverrouter]	"discoverrouter",
+[OBrsserver]		"rsserver",
+[OBstaticroutes]	"staticroutes",
+[OBtrailerencap]	"trailerencap",
+[OBarptimeout]		"arptimeout",
+[OBetherencap]		"etherencap",
+[OBtcpttl]		"tcpttl",
+[OBtcpka]		"tcpka",
+[OBtcpkag]		"tcpkag",
+[OBnisdomain]		"nisdomain",
+[OBniserver]		"niserver",
+[OBntpserver]		"ntpserver",
+[OBvendorinfo]		"vendorinfo",
+[OBnetbiosns]		"NBns",
+[OBnetbiosdds]		"NBdds",
+[OBnetbiostype]		"NBtype",
+[OBnetbiosscope]	"NBscope",
+[OBxfontserver]		"xfont",
+[OBxdispmanager]	"xdisp",
+[OBnisplusdomain]	"NPdomain",
+[OBnisplusserver]	"NP",
+[OBhomeagent]		"homeagent",
+[OBsmtpserver]		"smtp",
+[OBpop3server]		"pop3",
+[OBnntpserver]		"nntp",
+[OBwwwserver]		"www",
+[OBfingerserver]	"finger",
+[OBircserver]		"ircserver",
+[OBstserver]		"stserver",
+[OBstdaserver]		"stdaserver",
+
+/* dhcp options */
+[ODipaddr]		"ip",
+[ODlease]		"leas",
+[ODoverload]		"overload",
+[ODtype]		"typ",
+[ODserverid]		"sid",
+[ODparams]		"params",
+[ODmessage]		"message",
+[ODmaxmsg]		"maxmsg",
+[ODrenewaltime]		"renewaltime",
+[ODrebindingtime]	"rebindingtime",
+[ODvendorclass]		"vendorclass",
+[ODclientid]		"cid",
+[ODtftpserver]		"tftpserver",
+[ODbootfile]		"bf",
+};
+
+void	addropt(Req*, int, uchar*);
+void	addrsopt(Req*, int, uchar**, int);
+void	arpenter(uchar*, uchar*);
+void	bootp(Req*);
+void	byteopt(Req*, int, uchar);
+void	dhcp(Req*);
+void	fatal(int, char*, ...);
+void	hexopt(Req*, int, char*);
+void	logdhcp(Req*);
+void	logdhcpout(Req *, char *);
+void	longopt(Req*, int, long);
+void	maskopt(Req*, int, uchar*);
+void	miscoptions(Req*, uchar*);
+int	openlisten(char *net);
+void	p9addrsopt(Req *rp, int t, uchar **ip, int i);
+void	parseoptions(Req*);
+void	proto(Req*, int);
+void	rcvdecline(Req*);
+void	rcvdiscover(Req*);
+void	rcvinform(Req*);
+void	rcvrelease(Req*);
+void	rcvrequest(Req*);
+int	readlast(int, uchar*, int);
+char*	readsysname(void);
+void	remrequested(Req*, int);
+void	sendack(Req*, uchar*, int, int);
+void	sendnak(Req*, char*);
+void	sendoffer(Req*, uchar*, int);
+void	stringopt(Req*, int, char*);
+void	termopt(Req*);
+int	validip(uchar*);
+void	vectoropt(Req*, int, uchar*, int);
+void	warning(int, char*, ...);
+
+void
+timestamp(char *tag)
+{
+	uvlong t;
+
+	t = nsec()/1000;
+	syslog(0, blog, "%s %lludµs", tag, t - start);
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: dhcp [-dmnprsSZ] [-f directory] [-M minlease] "
+		"[-x netmtpt] [-Z staticlease] addr n [addr n] ...\n");
+	exits("usage");
+}
+
+void
+main(int argc, char **argv)
+{
+	int i, n, fd;
+	uchar ip[IPaddrlen];
+	Req r;
+
+	setnetmtpt(net, sizeof net, nil);
+
+	fmtinstall('E', eipfmt);
+	fmtinstall('I', eipfmt);
+	fmtinstall('V', eipfmt);
+	fmtinstall('M', eipfmt);
+	ARGBEGIN {
+	case '6':
+		v6opts = 1;
+		break;
+	case 'd':
+		debug = 1;
+		break;
+	case 'f':
+		ndbfile = EARGF(usage());
+		break;
+	case 'm':
+		mute = 1;
+		break;
+	case 'M':
+		minlease = atoi(EARGF(usage()));
+		if(minlease <= 0)
+			minlease = MinLease;
+		break;
+	case 'n':
+		nobootp = 1;
+		break;
+	case 'p':
+		pptponly = 1;
+		break;
+	case 'r':
+		mutestat = 1;
+		break;
+	case 's':
+		slowstat = 1;
+		break;
+	case 'S':
+		slowdyn = 1;
+		break;
+	case 'x':
+		setnetmtpt(net, sizeof net, EARGF(usage()));
+		break;
+	case 'Z':
+		staticlease = atoi(EARGF(usage()));
+		if(staticlease <= 0)
+			staticlease = StaticLease;
+		break;
+	default:
+		usage();
+		break;
+	} ARGEND;
+
+	while(argc > 1){
+		parseip(ip, argv[0]);
+		if(!validip(ip))
+			usage();
+		n = atoi(argv[1]);
+		if(n <= 0)
+			usage();
+		initbinding(ip, n);
+		argc -= 2;
+		argv += 2;
+	}
+
+	/* for debugging */
+	for(i = 0; i < 256; i++)
+		if(optname[i] == 0)
+			optname[i] = smprint("%d", i);
+
+	/* what is my name? */
+	strcpy(mysysname, readsysname());
+
+	/* put process in background */
+	if(!debug)
+	switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
+	case -1:
+		fatal(1, "fork");
+	case 0:
+		break;
+	default:
+		exits(0);
+	}
+
+	if (chdir(TFTP) < 0)
+		warning(1, "can't change directory to %s", TFTP);
+	fd = openlisten(net);
+
+	for(;;){
+		memset(&r, 0, sizeof(r));
+		r.fd = fd;
+		n = readlast(r.fd, r.buf, sizeof(r.buf));
+		if(n < Udphdrsize)
+			fatal(1, "error reading requests");
+		start = nsec()/1000;
+		op = optbuf;
+		*op = 0;
+		proto(&r, n);
+		if(r.id != nil)
+			free(r.id);
+	}
+}
+
+void
+proto(Req *rp, int n)
+{
+	uchar relip[IPaddrlen];
+	char buf[64];
+
+	now = time(0);
+
+	rp->e = rp->buf + n;
+	rp->bp = (Bootp*)rp->buf;
+	rp->up = (Udphdr*)rp->buf;
+	if (ipcmp(rp->up->laddr, IPv4bcast) == 0)
+		ipmove(rp->up->laddr, rp->up->ifcaddr);
+	rp->max = rp->buf + Udphdrsize + MINSUPPORTED - IPUDPHDRSIZE;
+	rp->p = rp->bp->optdata;
+	v4tov6(rp->giaddr, rp->bp->giaddr);
+	v4tov6(rp->ciaddr, rp->bp->ciaddr);
+
+	if(pptponly && rp->bp->htype != 0)
+		return;
+
+	ipifcs = readipifc(net, ipifcs, -1);
+	if(validip(rp->giaddr))
+		ipmove(relip, rp->giaddr);
+	else if(validip(rp->up->raddr))
+		ipmove(relip, rp->up->raddr);
+	else
+		ipmove(relip, rp->up->laddr);
+	if(rp->e < (uchar*)rp->bp->sname){
+		warning(0, "packet too short");
+		return;
+	}
+	if(rp->bp->op != Bootrequest){
+		warning(0, "not bootrequest");
+		return;
+	}
+
+	if(rp->e >= rp->bp->optdata){
+		if(memcmp(rp->bp->optmagic, plan9opt, sizeof(rp->bp->optmagic)) == 0)
+			rp->p9request = 1;
+		if(memcmp(rp->bp->optmagic, genericopt, sizeof(rp->bp->optmagic)) == 0) {
+			rp->genrequest = 1;
+			parseoptions(rp);
+		}
+	}
+	rp->p = rp->bp->optdata;
+
+	/*  If no id is specified, make one from the hardware address
+	 *  of the target.  We assume all zeros is not a hardware address
+	 *  which could be a mistake.
+	 */
+	if(rp->id == nil){
+		if(rp->bp->hlen > Maxhwlen){
+			warning(0, "hlen %d", rp->bp->hlen);
+			return;
+		}
+		if(memcmp(zeros, rp->bp->chaddr, rp->bp->hlen) == 0){
+			warning(0, "no chaddr");
+			return;
+		}
+		sprint(buf, "hwa%2.2ux_", rp->bp->htype);
+		rp->id = tohex(buf, rp->bp->chaddr, rp->bp->hlen);
+	}
+
+	/* info about gateway */
+	if(lookupip(relip, &rp->gii, 1) < 0){
+		warning(0, "lookupip failed");
+		return;
+	}
+
+	/* info about target system */
+	if(lookup(rp->bp, &rp->ii, &rp->gii) == 0)
+		if(rp->ii.indb && rp->ii.dhcpgroup[0] == 0)
+			rp->staticbinding = 1;
+
+	if(rp->dhcptype)
+		dhcp(rp);
+	else
+		bootp(rp);
+	timestamp("done");
+}
+
+static void
+slowdelay(Req *rp)
+{
+	if(slowstat && rp->staticbinding || slowdyn && !rp->staticbinding)
+		sleep(2000);
+}
+
+void
+dhcp(Req *rp)
+{
+	logdhcp(rp);
+
+	switch(rp->dhcptype){
+	case Discover:
+		slowdelay(rp);
+		rcvdiscover(rp);
+		break;
+	case Request:
+		rcvrequest(rp);
+		break;
+	case Decline:
+		rcvdecline(rp);
+		break;
+	case Release:
+		rcvrelease(rp);
+		break;
+	case Inform:
+		rcvinform(rp);
+		break;
+	}
+}
+
+void
+rcvdiscover(Req *rp)
+{
+	Binding *b, *nb;
+
+	if(rp->staticbinding){
+		sendoffer(rp, rp->ii.ipaddr, (staticlease > minlease? staticlease: minlease));
+		return;
+	}
+
+	/*
+	 *  first look for an outstanding offer
+	 */
+	b = idtooffer(rp->id, &rp->gii);
+
+	/*
+	 * rfc2131 says:
+	 *   If an address is available, the new address
+	 *   SHOULD be chosen as follows:
+	 *
+	 *      o The client's current address as recorded in the client's current
+	 *        binding, ELSE
+	 *
+	 *      o The client's previous address as recorded in the client's (now
+	 *        expired or released) binding, if that address is in the server's
+	 *        pool of available addresses and not already allocated, ELSE
+	 *
+	 *      o The address requested in the 'Requested IP Address' option, if that
+	 *        address is valid and not already allocated, ELSE
+	 *
+	 *      o A new address allocated from the server's pool of available
+	 *        addresses; the address is selected based on the subnet from which
+	 *        the message was received (if 'giaddr' is 0) or on the address of
+	 *        the relay agent that forwarded the message ('giaddr' when not 0).
+	 */
+	if(b == nil){
+		b = idtobinding(rp->id, &rp->gii, 1);
+		if(b && b->boundto && strcmp(b->boundto, rp->id) != 0)
+		if(validip(rp->ip) && samenet(rp->ip, &rp->gii)){
+			nb = iptobinding(rp->ip, 0);
+			if(nb && nb->lease < now)
+				b = nb;
+		}
+	}
+	if(b == nil){
+		warning(0, "!Discover(%s via %I): no binding %I",
+			rp->id, rp->gii.ipaddr, rp->ip);
+		return;
+	}
+	mkoffer(b, rp->id, rp->leasetime);
+	sendoffer(rp, b->ip, b->offer);
+}
+
+void
+rcvrequest(Req *rp)
+{
+	Binding *b;
+
+	if(validip(rp->server)){
+		/* this is a reply to an offer - SELECTING */
+
+		/* check for hard assignment */
+		if(rp->staticbinding){
+			if(forme(rp->server))
+				sendack(rp, rp->ii.ipaddr,
+					(staticlease > minlease? staticlease:
+					minlease), 1);
+			else
+				warning(0, "!Request(%s via %I): for server %I not me",
+					rp->id, rp->gii.ipaddr, rp->server);
+			return;
+		}
+
+		b = idtooffer(rp->id, &rp->gii);
+
+		/* if we don't have an offer, nak */
+		if(b == nil){
+			warning(0, "!Request(%s via %I): no offer",
+				rp->id, rp->gii.ipaddr);
+			if(forme(rp->server))
+				sendnak(rp, "no offer for you");
+			return;
+		}
+
+		/* if not for me, retract offer */
+		if(!forme(rp->server)){
+			b->expoffer = 0;
+			warning(0, "!Request(%s via %I): for server %I not me",
+				rp->id, rp->gii.ipaddr, rp->server);
+			return;
+		}
+
+		/*
+		 *  if the client is confused about what we offered, nak.
+		 *  client really shouldn't be specifying this when selecting
+		 */
+		if(validip(rp->ip) && ipcmp(rp->ip, b->ip) != 0){
+			warning(0, "!Request(%s via %I): requests %I, not %I",
+				rp->id, rp->gii.ipaddr, rp->ip, b->ip);
+			sendnak(rp, "bad ip address option");
+			return;
+		}
+		if(commitbinding(b) < 0){
+			warning(0, "!Request(%s via %I): can't commit %I",
+				rp->id, rp->gii.ipaddr, b->ip);
+			sendnak(rp, "can't commit binding");
+			return;
+		}
+		sendack(rp, b->ip, b->offer, 1);
+	} else if(validip(rp->ip)){
+		/*
+		 *  checking address/net - INIT-REBOOT
+		 *
+		 *  This is a rebooting client that remembers its old
+		 *  address.
+		 */
+		/* check for hard assignment */
+		if(rp->staticbinding){
+			if(memcmp(rp->ip, rp->ii.ipaddr, IPaddrlen) != 0){
+				warning(0, "!Request(%s via %I): %I not valid for %E",
+					rp->id, rp->gii.ipaddr, rp->ip, rp->bp->chaddr);
+				sendnak(rp, "not valid");
+			}
+			sendack(rp, rp->ii.ipaddr, (staticlease > minlease?
+				staticlease: minlease), 1);
+			return;
+		}
+
+		/* make sure the network makes sense */
+		if(!samenet(rp->ip, &rp->gii)){
+			warning(0, "!Request(%s via %I): bad forward of %I",
+				rp->id, rp->gii.ipaddr, rp->ip);
+			sendnak(rp, "wrong network");
+			return;
+		}
+		b = iptobinding(rp->ip, 0);
+		if(b == nil){
+			warning(0, "!Request(%s via %I): no binding for %I",
+				rp->id, rp->gii.ipaddr, rp->ip);
+			return;
+		}
+		if(memcmp(rp->ip, b->ip, IPaddrlen) != 0 || now > b->lease){
+			warning(0, "!Request(%s via %I): %I not valid",
+				rp->id, rp->gii.ipaddr, rp->ip);
+			sendnak(rp, "not valid");
+			return;
+		}
+		b->offer = b->lease - now;
+		sendack(rp, b->ip, b->offer, 1);
+	} else if(validip(rp->ciaddr)){
+		/*
+		 *  checking address - RENEWING or REBINDING
+		 *
+		 *  these states are indistinguishable in our action.  The only
+		 *  difference is how close to lease expiration the client is.
+		 *  If it is really close, it broadcasts the request hoping that
+		 *  some server will answer.
+		 */
+
+		/* check for hard assignment */
+		if(rp->staticbinding){
+			if(ipcmp(rp->ciaddr, rp->ii.ipaddr) != 0){
+				warning(0, "!Request(%s via %I): %I not valid",
+					rp->id, rp->gii.ipaddr, rp->ciaddr);
+				sendnak(rp, "not valid");
+			}
+			sendack(rp, rp->ii.ipaddr, (staticlease > minlease?
+				staticlease: minlease), 1);
+			return;
+		}
+
+		/* make sure the network makes sense */
+		if(!samenet(rp->ciaddr, &rp->gii)){
+			warning(0, "!Request(%s via %I): bad forward of %I",
+				rp->id, rp->gii.ipaddr, rp->ip);
+			sendnak(rp, "wrong network");
+			return;
+		}
+		b = iptobinding(rp->ciaddr, 0);
+		if(b == nil){
+			warning(0, "!Request(%s via %I): no binding for %I",
+				rp->id, rp->gii.ipaddr, rp->ciaddr);
+			return;
+		}
+		if(ipcmp(rp->ciaddr, b->ip) != 0){
+			warning(0, "!Request(%I via %s): %I not valid",
+				rp->id, rp->gii.ipaddr, rp->ciaddr);
+			sendnak(rp, "invalid ip address");
+			return;
+		}
+		mkoffer(b, rp->id, rp->leasetime);
+		if(commitbinding(b) < 0){
+			warning(0, "!Request(%s via %I): can't commit %I",
+				rp->id, rp->gii.ipaddr, b->ip);
+			sendnak(rp, "can't commit binding");
+			return;
+		}
+		sendack(rp, b->ip, b->offer, 1);
+	}
+}
+
+void
+rcvdecline(Req *rp)
+{
+	Binding *b;
+	char buf[64];
+
+	if(rp->staticbinding)
+		return;
+
+	b = idtooffer(rp->id, &rp->gii);
+	if(b == nil){
+		warning(0, "!Decline(%s via %I): no binding",
+			rp->id, rp->gii.ipaddr);
+		return;
+	}
+
+	/* mark ip address as in use */
+	snprint(buf, sizeof(buf), "declined by %s", rp->id);
+	mkoffer(b, buf, 0x7fffffff);
+	commitbinding(b);
+}
+
+void
+rcvrelease(Req *rp)
+{
+	Binding *b;
+
+	if(rp->staticbinding)
+		return;
+
+	b = idtobinding(rp->id, &rp->gii, 0);
+	if(b == nil){
+		warning(0, "!Release(%s via %I): no binding",
+			rp->id, rp->gii.ipaddr);
+		return;
+	}
+	if(strcmp(rp->id, b->boundto) != 0){
+		warning(0, "!Release(%s via %I): invalid release of %I",
+			rp->id, rp->gii.ipaddr, rp->ip);
+		return;
+	}
+	warning(0, "Release(%s via %I): releasing %I", b->boundto, rp->gii.ipaddr, b->ip);
+	if(releasebinding(b, rp->id) < 0)
+		warning(0, "release: couldn't release");
+}
+
+void
+rcvinform(Req *rp)
+{
+	Binding *b;
+
+	if(rp->staticbinding){
+		sendack(rp, rp->ii.ipaddr, 0, 0);
+		return;
+	}
+
+	b = iptobinding(rp->ciaddr, 0);
+	if(b == nil){
+		warning(0, "!Inform(%s via %I): no binding for %I",
+			rp->id, rp->gii.ipaddr, rp->ip);
+		return;
+	}
+	sendack(rp, b->ip, 0, 0);
+}
+
+int
+setsiaddr(uchar *siaddr, uchar *saddr, uchar *laddr)
+{
+	if(ipcmp(saddr, IPnoaddr) != 0){
+		v6tov4(siaddr, saddr);
+		return 0;
+	} else {
+		v6tov4(siaddr, laddr);
+		return 1;
+	}
+}
+
+int
+ismuted(Req *rp)
+{
+	return mute || (mutestat && rp->staticbinding);
+}
+
+void
+sendoffer(Req *rp, uchar *ip, int offer)
+{
+	int n;
+	ushort flags;
+	Bootp *bp;
+	Udphdr *up;
+
+	bp = rp->bp;
+	up = rp->up;
+
+	/*
+	 *  set destination
+	 */
+	flags = nhgets(bp->flags);
+	if(validip(rp->giaddr)){
+		ipmove(up->raddr, rp->giaddr);
+		hnputs(up->rport, 67);
+	} else if(flags & Fbroadcast){
+		ipmove(up->raddr, IPv4bcast);
+		hnputs(up->rport, 68);
+	} else {
+		ipmove(up->raddr, ip);
+		if(bp->htype == 1)
+			arpenter(up->raddr, bp->chaddr);
+		hnputs(up->rport, 68);
+	}
+
+	/*
+	 *  fill in standard bootp part
+	 */
+	bp->op = Bootreply;
+	bp->hops = 0;
+	hnputs(bp->secs, 0);
+	memset(bp->ciaddr, 0, sizeof(bp->ciaddr));
+	v6tov4(bp->giaddr, rp->giaddr);
+	v6tov4(bp->yiaddr, ip);
+	setsiaddr(bp->siaddr, rp->ii.tftp, up->laddr);
+	strncpy(bp->sname, mysysname, sizeof(bp->sname));
+	strncpy(bp->file, rp->ii.bootf, sizeof(bp->file));
+
+	/*
+	 *  set options
+	 */
+	byteopt(rp, ODtype, Offer);
+	longopt(rp, ODlease, offer);
+	addropt(rp, ODserverid, up->laddr);
+	miscoptions(rp, ip);
+	termopt(rp);
+
+	logdhcpout(rp, "Offer");
+
+	/*
+	 *  send
+	 */
+	n = rp->p - rp->buf;
+	if(!ismuted(rp) && write(rp->fd, rp->buf, n) != n)
+		warning(0, "offer: write failed: %r");
+}
+
+void
+sendack(Req *rp, uchar *ip, int offer, int sendlease)
+{
+	int n;
+	ushort flags;
+	Bootp *bp;
+	Udphdr *up;
+
+	bp = rp->bp;
+	up = rp->up;
+
+	/*
+	 *  set destination
+	 */
+	flags = nhgets(bp->flags);
+	if(validip(rp->giaddr)){
+		ipmove(up->raddr, rp->giaddr);
+		hnputs(up->rport, 67);
+	} else if(flags & Fbroadcast){
+		ipmove(up->raddr, IPv4bcast);
+		hnputs(up->rport, 68);
+	} else {
+		ipmove(up->raddr, ip);
+		if(bp->htype == 1)
+			arpenter(up->raddr, bp->chaddr);
+		hnputs(up->rport, 68);
+	}
+
+	/*
+	 *  fill in standard bootp part
+	 */
+	bp->op = Bootreply;
+	bp->hops = 0;
+	hnputs(bp->secs, 0);
+	v6tov4(bp->giaddr, rp->giaddr);
+	v6tov4(bp->yiaddr, ip);
+	setsiaddr(bp->siaddr, rp->ii.tftp, up->laddr);
+	strncpy(bp->sname, mysysname, sizeof(bp->sname));
+	strncpy(bp->file, rp->ii.bootf, sizeof(bp->file));
+
+	/*
+	 *  set options
+	 */
+	byteopt(rp, ODtype, Ack);
+	if(sendlease){
+		longopt(rp, ODlease, offer);
+	}
+	addropt(rp, ODserverid, up->laddr);
+	miscoptions(rp, ip);
+	termopt(rp);
+
+	logdhcpout(rp, "Ack");
+
+	/*
+	 *  send
+	 */
+	n = rp->p - rp->buf;
+	if(!ismuted(rp) && write(rp->fd, rp->buf, n) != n)
+		warning(0, "ack: write failed: %r");
+}
+
+void
+sendnak(Req *rp, char *msg)
+{
+	int n;
+	Bootp *bp;
+	Udphdr *up;
+
+	bp = rp->bp;
+	up = rp->up;
+
+	/*
+	 *  set destination (always broadcast)
+	 */
+	if(validip(rp->giaddr)){
+		ipmove(up->raddr, rp->giaddr);
+		hnputs(up->rport, 67);
+	} else {
+		ipmove(up->raddr, IPv4bcast);
+		hnputs(up->rport, 68);
+	}
+
+	/*
+	 *  fill in standard bootp part
+	 */
+	bp->op = Bootreply;
+	bp->hops = 0;
+	hnputs(bp->secs, 0);
+	v6tov4(bp->giaddr, rp->giaddr);
+	memset(bp->ciaddr, 0, sizeof(bp->ciaddr));
+	memset(bp->yiaddr, 0, sizeof(bp->yiaddr));
+	memset(bp->siaddr, 0, sizeof(bp->siaddr));
+
+	/*
+	 *  set options
+	 */
+	byteopt(rp, ODtype, Nak);
+	addropt(rp, ODserverid, up->laddr);
+	if(msg)
+		stringopt(rp, ODmessage, msg);
+	if(strncmp(rp->id, "id", 2) == 0)
+		hexopt(rp, ODclientid, rp->id+2);
+	termopt(rp);
+
+	logdhcpout(rp, "Nak");
+
+	/*
+	 *  send nak
+	 */
+	n = rp->p - rp->buf;
+	if(!ismuted(rp) && write(rp->fd, rp->buf, n) != n)
+		warning(0, "nak: write failed: %r");
+}
+
+void
+bootp(Req *rp)
+{
+	int n;
+	Bootp *bp;
+	Udphdr *up;
+	ushort flags;
+	Iplifc *lifc;
+	Info *iip;
+
+	warning(0, "bootp %s %I->%I from %s via %I, file %s",
+		rp->genrequest? "generic": (rp->p9request? "p9": ""),
+		rp->up->raddr, rp->up->laddr,
+		rp->id, rp->gii.ipaddr,
+		rp->bp->file);
+
+	if(nobootp)
+		return;
+
+	bp = rp->bp;
+	up = rp->up;
+	iip = &rp->ii;
+
+	if(rp->staticbinding == 0){
+		warning(0, "bootp from unknown %s via %I", rp->id, rp->gii.ipaddr);
+		return;
+	}
+
+	/* ignore if not for us */
+	if(*bp->sname){
+		if(strcmp(bp->sname, mysysname) != 0){
+			bp->sname[20] = 0;
+			warning(0, "bootp for server %s", bp->sname);
+			return;
+		}
+	} else
+		slowdelay(rp);
+
+	/* ignore if we don't know what file to load */
+	if(*bp->file == 0){
+		if(rp->genrequest && *iip->bootf2) /* if not plan 9 & have alternate file... */
+			strncpy(bp->file, iip->bootf2, sizeof(bp->file));
+		else if(*iip->bootf)
+			strncpy(bp->file, iip->bootf, sizeof(bp->file));
+		else if(*bp->sname) /* if we were asked, respond no matter what */
+			bp->file[0] = '\0';
+		else {
+			warning(0, "no bootfile for %I", iip->ipaddr);
+			return;
+		}
+	}
+
+	/* ignore if the file is unreadable */
+	if((!rp->genrequest) && bp->file[0] && access(bp->file, 4) < 0){
+		warning(0, "inaccessible bootfile1 %s", bp->file);
+		return;
+	}
+
+	bp->op = Bootreply;
+	v6tov4(bp->yiaddr, iip->ipaddr);
+	if(rp->p9request){
+		warning(0, "p9bootp: %I", iip->ipaddr);
+		memmove(bp->optmagic, plan9opt, 4);
+		if(iip->gwip == 0)
+			v4tov6(iip->gwip, bp->giaddr);
+		rp->p += sprint((char*)rp->p, "%V %I %I %I", iip->ipmask+IPv4off, iip->fsip,
+				iip->auip, iip->gwip);
+		sprint(optbuf, "%s", (char*)(bp->optmagic));
+	} else if(rp->genrequest){
+		warning(0, "genericbootp: %I", iip->ipaddr);
+		memmove(bp->optmagic, genericopt, 4);
+		miscoptions(rp, iip->ipaddr);
+		termopt(rp);
+	} else if(iip->vendor[0] != 0) {
+		warning(0, "bootp vendor field: %s", iip->vendor);
+		memset(rp->p, 0, 128-4);
+		rp->p += sprint((char*)bp->optmagic, "%s", iip->vendor);
+	} else {
+		memset(rp->p, 0, 128-4);
+		rp->p += 128-4;
+	}
+
+	/*
+	 *  set destination
+	 */
+	flags = nhgets(bp->flags);
+	if(validip(rp->giaddr)){
+		ipmove(up->raddr, rp->giaddr);
+		hnputs(up->rport, 67);
+	} else if(flags & Fbroadcast){
+		ipmove(up->raddr, IPv4bcast);
+		hnputs(up->rport, 68);
+	} else {
+		v4tov6(up->raddr, bp->yiaddr);
+		if(bp->htype == 1)
+			arpenter(up->raddr, bp->chaddr);
+		hnputs(up->rport, 68);
+	}
+
+	/*
+	 *  select best local address if destination is directly connected
+	 */
+	lifc = findlifc(up->raddr);
+	if(lifc)
+		ipmove(up->laddr, lifc->ip);
+
+	/*
+	 *  our identity
+	 */
+	strncpy(bp->sname, mysysname, sizeof(bp->sname));
+
+	/*
+	 *  set tftp server
+	 */
+	setsiaddr(bp->siaddr, iip->tftp, up->laddr);
+	if(rp->genrequest && *iip->bootf2)
+		setsiaddr(bp->siaddr, iip->tftp2, up->laddr);
+
+	/*
+	 * RFC 1048 says that we must pad vendor field with
+	 * zeros until we have a 64 byte field.
+	 */
+	n = rp->p - rp->bp->optdata;
+	if(n < 64-4) {
+		memset(rp->p, 0, (64-4)-n);
+		rp->p += (64-4)-n;
+	}
+
+	/*
+	 *  send
+	 */
+	n = rp->p - rp->buf;
+	if(!ismuted(rp) && write(rp->fd, rp->buf, n) != n)
+		warning(0, "bootp: write failed: %r");
+
+	warning(0, "bootp via %I: file %s xid(%ux)flag(%ux)ci(%V)gi(%V)yi(%V)si(%V) %s",
+			up->raddr, bp->file, nhgetl(bp->xid), nhgets(bp->flags),
+			bp->ciaddr, bp->giaddr, bp->yiaddr, bp->siaddr,
+			optbuf);
+}
+
+void
+parseoptions(Req *rp)
+{
+	int n, c, code;
+	uchar *o, *p;
+
+	p = rp->p;
+
+	while(p < rp->e){
+		code = *p++;
+		if(code == 255)
+			break;
+		if(code == 0)
+			continue;
+
+		/* ignore anything that's too long */
+		n = *p++;
+		o = p;
+		p += n;
+		if(p > rp->e)
+			return;
+
+		switch(code){
+		case ODipaddr:	/* requested ip address */
+			if(n == IPv4addrlen)
+				v4tov6(rp->ip, o);
+			break;
+		case ODlease:	/* requested lease time */
+			rp->leasetime = nhgetl(o);
+			if(rp->leasetime > MaxLease || rp->leasetime < 0)
+				rp->leasetime = MaxLease;
+			break;
+		case ODtype:
+			c = *o;
+			if(c < 10 && c > 0)
+				rp->dhcptype = c;
+			break;
+		case ODserverid:
+			if(n == IPv4addrlen)
+				v4tov6(rp->server, o);
+			break;
+		case ODmessage:
+			if(n > sizeof rp->msg-1)
+				n = sizeof rp->msg-1;
+			memmove(rp->msg, o, n);
+			rp->msg[n] = 0;
+			break;
+		case ODmaxmsg:
+			c = nhgets(o);
+			c -= 28;
+			c += Udphdrsize;
+			if(c > 0)
+				rp->max = rp->buf + c;
+			break;
+		case ODclientid:
+			if(n <= 1)
+				break;
+			rp->id = toid( o, n);
+			break;
+		case ODparams:
+			if(n > sizeof(rp->requested))
+				n = sizeof(rp->requested);
+			memmove(rp->requested, o, n);
+			break;
+		case ODvendorclass:
+			if(n >= sizeof(rp->vendorclass))
+				n = sizeof(rp->vendorclass)-1;
+			memmove(rp->vendorclass, o, n);
+			rp->vendorclass[n] = 0;
+			if(strncmp((char*)rp->vendorclass, "p9-", 3) == 0)
+				strcpy(rp->cputype, (char*)rp->vendorclass+3);
+			break;
+		case OBend:
+			return;
+		}
+	}
+}
+
+void
+remrequested(Req *rp, int opt)
+{
+	uchar *p;
+
+	p = memchr(rp->requested, opt, sizeof(rp->requested));
+	if(p != nil)
+		*p = OBpad;
+}
+
+void
+miscoptions(Req *rp, uchar *ip)
+{
+	int i, j, na;
+	uchar x[2*IPaddrlen], vopts[Maxoptlen];
+	uchar *op, *omax;
+	uchar *addrs[2];
+	char *p;
+	char *attr[100], **a;
+	Ndbtuple *t;
+
+	addrs[0] = x;
+	addrs[1] = x+IPaddrlen;
+
+	/* always supply these */
+	maskopt(rp, OBmask, rp->gii.ipmask);
+	if(validip(rp->gii.gwip)){
+		remrequested(rp, OBrouter);
+		addropt(rp, OBrouter, rp->gii.gwip);
+	} else if(validip(rp->giaddr)){
+		remrequested(rp, OBrouter);
+		addropt(rp, OBrouter, rp->giaddr);
+	}
+
+	/*
+	 * OBhostname for the HP4000M switches
+	 * (this causes NT to log infinite errors - tough shit)
+	 */
+	if(*rp->ii.domain){
+		remrequested(rp, OBhostname);
+		stringopt(rp, OBhostname, rp->ii.domain);
+	}
+	if(*rp->ii.rootpath)
+		stringopt(rp, OBrootpath, rp->ii.rootpath);
+
+	/* figure out what we need to lookup */
+	na = 0;
+	a = attr;
+	if(*rp->ii.domain == 0)
+		a[na++] = "dom";
+	for(i = 0; i < sizeof(rp->requested); i++)
+		switch(rp->requested[i]){
+		case OBrouter:
+			a[na++] = "@ipgw";
+			break;
+		case OBdnserver:
+			a[na++] = "@dns";
+			break;
+		case OBnetbiosns:
+			a[na++] = "@wins";
+			break;
+		case OBsmtpserver:
+			a[na++] = "@smtp";
+			break;
+		case OBpop3server:
+			a[na++] = "@pop3";
+			break;
+		case OBwwwserver:
+			a[na++] = "@www";
+			break;
+		case OBntpserver:
+			a[na++] = "@ntp";
+			break;
+		case OBtimeserver:
+			a[na++] = "@time";
+			break;
+		}
+	if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0
+	|| strncmp((char*)rp->vendorclass, "p9-", 3) == 0){
+		a[na++] = "@fs";
+		a[na++] = "@auth";
+	}
+	t = lookupinfo(ip, a, na);
+
+	/* lookup anything we might be missing */
+	if(*rp->ii.domain == 0)
+		lookupname(rp->ii.domain, t);
+
+	/* add any requested ones that we know about */
+	for(i = 0; i < sizeof(rp->requested); i++)
+		switch(rp->requested[i]){
+		case OBrouter:
+			j = lookupserver("ipgw", addrs, t);
+			addrsopt(rp, OBrouter, addrs, j);
+			break;
+		case OBdnserver:
+			j = lookupserver("dns", addrs, t);
+			addrsopt(rp, OBdnserver, addrs, j);
+			break;
+		case OBhostname:
+			if(*rp->ii.domain)
+				stringopt(rp, OBhostname, rp->ii.domain);
+			break;
+		case OBdomainname:
+			p = strchr(rp->ii.domain, '.');
+			if(p)
+				stringopt(rp, OBdomainname, p+1);
+			break;
+		case OBnetbiosns:
+			j = lookupserver("wins", addrs, t);
+			addrsopt(rp, OBnetbiosns, addrs, j);
+			break;
+		case OBnetbiostype:
+			/* p-node: peer to peer WINS queries */
+			byteopt(rp, OBnetbiostype, 0x2);
+			break;
+		case OBsmtpserver:
+			j = lookupserver("smtp", addrs, t);
+			addrsopt(rp, OBsmtpserver, addrs, j);
+			break;
+		case OBpop3server:
+			j = lookupserver("pop3", addrs, t);
+			addrsopt(rp, OBpop3server, addrs, j);
+			break;
+		case OBwwwserver:
+			j = lookupserver("www", addrs, t);
+			addrsopt(rp, OBwwwserver, addrs, j);
+			break;
+		case OBntpserver:
+			j = lookupserver("ntp", addrs, t);
+			addrsopt(rp, OBntpserver, addrs, j);
+			break;
+		case OBtimeserver:
+			j = lookupserver("time", addrs, t);
+			addrsopt(rp, OBtimeserver, addrs, j);
+			break;
+		case OBttl:
+			byteopt(rp, OBttl, 255);
+			break;
+		}
+
+	/* add plan9 specific options */
+	if(strncmp((char*)rp->vendorclass, "plan9_", 6) == 0
+	|| strncmp((char*)rp->vendorclass, "p9-", 3) == 0){
+		/* point to temporary area */
+		op = rp->p;
+		omax = rp->max;
+		/* stash encoded options in vopts */
+		rp->p = vopts;
+		rp->max = vopts + sizeof(vopts) - 1;
+
+		/* emit old v4 addresses first to make sure that they fit */
+		addrsopt(rp, OP9fsv4, addrs, lookupserver("fs", addrs, t));
+		addrsopt(rp, OP9authv4, addrs, lookupserver("auth", addrs, t));
+
+		p9addrsopt(rp, OP9fs, addrs, lookupserver("fs", addrs, t));
+		p9addrsopt(rp, OP9auth, addrs, lookupserver("auth", addrs, t));
+		p9addrsopt(rp, OP9ipaddr, addrs, lookupserver("ip", addrs, t));
+		p9addrsopt(rp, OP9ipmask, addrs, lookupserver("ipmask", addrs, t));
+		p9addrsopt(rp, OP9ipgw, addrs, lookupserver("ipgw", addrs, t));
+
+		/* point back to packet, encapsulate vopts into packet */
+		j = rp->p - vopts;
+		rp->p = op;
+		rp->max = omax;
+		vectoropt(rp, OBvendorinfo, vopts, j);
+	}
+
+	ndbfree(t);
+}
+
+int
+openlisten(char *net)
+{
+	int fd, cfd;
+	char data[128], devdir[40];
+
+	sprint(data, "%s/udp!*!bootp", net);
+	cfd = announce(data, devdir);
+	if(cfd < 0)
+		fatal(1, "can't announce");
+	if(fprint(cfd, "headers") < 0)
+		fatal(1, "can't set header mode");
+
+	sprint(data, "%s/data", devdir);
+	fd = open(data, ORDWR);
+	if(fd < 0)
+		fatal(1, "open udp data");
+	return fd;
+}
+
+void
+fatal(int syserr, char *fmt, ...)
+{
+	char buf[Maxloglen];
+	va_list arg;
+
+	va_start(arg, fmt);
+	vseprint(buf, buf+sizeof(buf), fmt, arg);
+	va_end(arg);
+	if(syserr)
+		syslog(1, blog, "%s: %r", buf);
+	else
+		syslog(1, blog, "%s", buf);
+	exits(buf);
+}
+
+void
+warning(int syserr, char *fmt, ...)
+{
+	char buf[Maxloglen];
+	va_list arg;
+
+	va_start(arg, fmt);
+	vseprint(buf, buf+sizeof(buf), fmt, arg);
+	va_end(arg);
+	if(syserr){
+		syslog(0, blog, "%s: %r", buf);
+		if(debug)
+			fprint(2, "%s: %r\n", buf);
+	} else {
+		syslog(0, blog, "%s", buf);
+		if(debug)
+			fprint(2, "%s\n", buf);
+	}
+}
+
+char*
+readsysname(void)
+{
+	static char name[128];
+	char *p;
+	int n, fd;
+
+	fd = open("/dev/sysname", OREAD);
+	if(fd >= 0){
+		n = read(fd, name, sizeof(name)-1);
+		close(fd);
+		if(n > 0){
+			name[n] = 0;
+			return name;
+		}
+	}
+	p = getenv("sysname");
+	if(p == nil || *p == 0)
+		return "unknown";
+	return p;
+}
+
+extern int
+validip(uchar *ip)
+{
+	if(ipcmp(ip, IPnoaddr) == 0)
+		return 0;
+	if(ipcmp(ip, v4prefix) == 0)
+		return 0;
+	return 1;
+}
+
+void
+longopt(Req *rp, int t, long v)
+{
+	if(rp->p + 6 > rp->max)
+		return;
+	*rp->p++ = t;
+	*rp->p++ = 4;
+	hnputl(rp->p, v);
+	rp->p += 4;
+
+	op = seprint(op, oe, "%s(%ld)", optname[t], v);
+}
+
+void
+addropt(Req *rp, int t, uchar *ip)
+{
+	if(rp->p + 6 > rp->max)
+		return;
+	if (!isv4(ip)) {
+		if (debug)
+			warning(0, "not a v4 %s server: %I", optname[t], ip);
+		return;
+	}
+	*rp->p++ = t;
+	*rp->p++ = 4;
+	memmove(rp->p, ip+IPv4off, 4);
+	rp->p += 4;
+
+	op = seprint(op, oe, "%s(%I)", optname[t], ip);
+}
+
+void
+maskopt(Req *rp, int t, uchar *ip)
+{
+	if(rp->p + 6 > rp->max)
+		return;
+	*rp->p++ = t;
+	*rp->p++ = 4;
+	memmove(rp->p, ip+IPv4off, 4);
+	rp->p += 4;
+
+	op = seprint(op, oe, "%s(%M)", optname[t], ip);
+}
+
+void
+addrsopt(Req *rp, int t, uchar **ip, int i)
+{
+	int v4s, n;
+
+	if(i <= 0)
+		return;
+	if(rp->p + 2 + 4*i > rp->max)
+		return;
+	v4s = 0;
+	for(n = i; n-- > 0; )
+		if (isv4(ip[n]))
+			v4s++;
+	if (v4s <= 0) {
+		if (debug)
+			warning(0, "no v4 %s servers", optname[t]);
+		return;
+	}
+	*rp->p++ = t;
+	*rp->p++ = 4*v4s;
+	op = seprint(op, oe, " %s(", optname[t]);
+	while(i-- > 0){
+		if (!isv4(*ip)) {
+			op = seprint(op, oe, " skipping %I ", *ip);
+			continue;
+		}
+		v6tov4(rp->p, *ip);
+		rp->p += 4;
+		op = seprint(op, oe, "%I", *ip);
+		ip++;
+		if(i > 0)
+			op = seprint(op, oe, " ");
+	}
+	op = seprint(op, oe, ")");
+}
+
+void
+p9addrsopt(Req *rp, int t, uchar **ip, int i)
+{
+	char *pkt, *payload;
+
+	if(i <= 0 || !v6opts)
+		return;
+	pkt = (char *)rp->p;
+	*pkt++ = t;			/* option */
+	pkt++;				/* fill in payload length below */
+	payload = pkt;
+	*pkt++ = i;			/* plan 9 address count */
+	op = seprint(op, oe, " %s(", optname[t]);
+	while(i-- > 0){
+		pkt = seprint(pkt, (char *)rp->max, "%I", *ip);
+		if ((uchar *)pkt+1 >= rp->max) {
+			op = seprint(op, oe, "<out of mem1>)");
+			return;
+		}
+		pkt++;			/* leave NUL as terminator */
+		op = seprint(op, oe, "%I", *ip);
+		ip++;
+		if(i > 0)
+			op = seprint(op, oe, " ");
+	}
+	if ((uchar *)pkt - rp->p > 0377) {
+		op = seprint(op, oe, "<out of mem2>)");
+		return;
+	}
+	op = seprint(op, oe, ")");
+	rp->p[1] = pkt - payload;	/* payload length */
+	rp->p = (uchar *)pkt;
+}
+
+void
+byteopt(Req *rp, int t, uchar v)
+{
+	if(rp->p + 3 > rp->max)
+		return;
+	*rp->p++ = t;
+	*rp->p++ = 1;
+	*rp->p++ = v;
+
+	op = seprint(op, oe, "%s(%d)", optname[t], v);
+}
+
+void
+termopt(Req *rp)
+{
+	if(rp->p + 1 > rp->max)
+		return;
+	*rp->p++ = OBend;
+}
+
+void
+stringopt(Req *rp, int t, char *str)
+{
+	int n;
+
+	n = strlen(str);
+	if(n > 255)
+		n = 255;
+	if(rp->p+n+2 > rp->max)
+		return;
+	*rp->p++ = t;
+	*rp->p++ = n;
+	memmove(rp->p, str, n);
+	rp->p += n;
+
+	op = seprint(op, oe, "%s(%s)", optname[t], str);
+}
+
+void
+vectoropt(Req *rp, int t, uchar *v, int n)
+{
+	int i;
+
+	if(n > 255) {
+		n = 255;
+		op = seprint(op, oe, "vectoropt len %d > 255 ", n);
+	}
+	if(rp->p+n+2 > rp->max)
+		return;
+	*rp->p++ = t;
+	*rp->p++ = n;
+	memmove(rp->p, v, n);
+	rp->p += n;
+
+	op = seprint(op, oe, "%s(", optname[t]);
+	if(n > 0)
+		op = seprint(op, oe, "%ud", v[0]);
+	for(i = 1; i < n; i++)
+		op = seprint(op, oe, " %ud", v[i]);
+	op = seprint(op, oe, ")");
+}
+
+int
+fromhex(int x)
+{
+	if(x >= '0' && x <= '9')
+		return x - '0';
+	return x - 'a';
+}
+
+void
+hexopt(Req *rp, int t, char *str)
+{
+	int n;
+
+	n = strlen(str);
+	n /= 2;
+	if(n > 255)
+		n = 255;
+	if(rp->p+n+2 > rp->max)
+		return;
+	*rp->p++ = t;
+	*rp->p++ = n;
+	while(n-- > 0){
+		*rp->p++ = (fromhex(str[0])<<4)|fromhex(str[1]);
+		str += 2;
+	}
+
+	op = seprint(op, oe, "%s(%s)", optname[t], str);
+}
+
+void
+arpenter(uchar *ip, uchar *ether)
+{
+	int f;
+	char buf[256];
+
+	sprint(buf, "%s/arp", net);
+	f = open(buf, OWRITE);
+	if(f < 0){
+		syslog(debug, blog, "open %s: %r", buf);
+		return;
+	}
+	fprint(f, "add ether %I %E", ip, ether);
+	close(f);
+}
+
+char *dhcpmsgname[] =
+{
+	[Discover]	"Discover",
+	[Offer]		"Offer",
+	[Request]	"Request",
+	[Decline]	"Decline",
+	[Ack]		"Ack",
+	[Nak]		"Nak",
+	[Release]	"Release",
+	[Inform]	"Inform",
+};
+
+void
+logdhcp(Req *rp)
+{
+	char buf[4096];
+	char *p, *e;
+	int i;
+
+	p = buf;
+	e = buf + sizeof(buf);
+	if(rp->dhcptype > 0 && rp->dhcptype <= Inform)
+		p = seprint(p, e, "%s(", dhcpmsgname[rp->dhcptype]);
+	else
+		p = seprint(p, e, "%d(", rp->dhcptype);
+	p = seprint(p, e, "%I->%I) xid(%ux)flag(%ux)", rp->up->raddr, rp->up->laddr,
+		nhgetl(rp->bp->xid), nhgets(rp->bp->flags));
+	if(rp->bp->htype == 1)
+		p = seprint(p, e, "ea(%E)", rp->bp->chaddr);
+	if(validip(rp->ciaddr))
+		p = seprint(p, e, "ci(%I)", rp->ciaddr);
+	if(validip(rp->giaddr))
+		p = seprint(p, e, "gi(%I)", rp->giaddr);
+	if(validip(rp->ip))
+		p = seprint(p, e, "ip(%I)", rp->ip);
+	if(rp->id != nil)
+		p = seprint(p, e, "id(%s)", rp->id);
+	if(rp->leasetime)
+		p = seprint(p, e, "leas(%d)", rp->leasetime);
+	if(validip(rp->server))
+		p = seprint(p, e, "sid(%I)", rp->server);
+	p = seprint(p, e, "need(");
+	for(i = 0; i < sizeof(rp->requested); i++)
+		if(rp->requested[i] != 0)
+			p = seprint(p, e, "%s ", optname[rp->requested[i]]);
+	p = seprint(p, e, ")");
+
+	USED(p);
+	syslog(0, blog, "%s", buf);
+}
+
+void
+logdhcpout(Req *rp, char *type)
+{
+	syslog(0, blog, "%s(%I-%I)id(%s)ci(%V)gi(%V)yi(%V)si(%V) %s",
+		type, rp->up->laddr, rp->up->raddr, rp->id,
+		rp->bp->ciaddr, rp->bp->giaddr, rp->bp->yiaddr, rp->bp->siaddr, optbuf);
+}
+
+/*
+ *  if we get behind, it's useless to try answering since the sender
+ *  will probably have retransmitted with a differnt sequence number.
+ *  So dump all but the last message in the queue.
+ */
+void
+ding(void*, char *msg)
+{
+	if(strstr(msg, "alarm"))
+		noted(NCONT);
+	else
+		noted(NDFLT);
+}
+
+int
+readlast(int fd, uchar *buf, int len)
+{
+	int lastn, n;
+
+	notify(ding);
+
+	lastn = 0;
+	for(;;){
+		alarm(20);
+		n = read(fd, buf, len);
+		alarm(0);
+		if(n < 0){
+			if(lastn > 0)
+				return lastn;
+			break;
+		}
+		lastn = n;
+	}
+	return read(fd, buf, len);
+}