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-rwxr-xr-xsrc/cmd/ip/dhcpd/dhcpd.c1632
1 files changed, 1632 insertions, 0 deletions
diff --git a/src/cmd/ip/dhcpd/dhcpd.c b/src/cmd/ip/dhcpd/dhcpd.c
new file mode 100755
index 00000000..3b0873c2
--- /dev/null
+++ b/src/cmd/ip/dhcpd/dhcpd.c
@@ -0,0 +1,1632 @@
+#include <u.h>
+#include <sys/socket.h>
+#include <net/if_arp.h>
+#include <netinet/ip.h>
+#include <sys/ioctl.h>
+#include <libc.h>
+#include <ip.h>
+#include <bio.h>
+#include <ndb.h>
+#include "dat.h"
+
+int bwfd;
+int wfd;
+
+//
+// ala rfc2131
+//
+
+typedef struct Req Req;
+struct Req
+{
+ int fd; /* for reply */
+ Bootp *bp;
+ Udphdr uh;
+ 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; /* true if this is a bootp with plan9 options */
+ int genrequest; /* true if 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 slow;
+char net[256];
+uchar xmyipaddr[IPaddrlen];
+
+int pptponly; // only answer request that came from the pptp server
+int mute;
+int minlease = MinLease;
+
+ulong start;
+
+/* 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 longopt(Req*, int, long);
+void maskopt(Req*, int, uchar*);
+void miscoptions(Req*, uchar*);
+int openlisten(char *net);
+void parseoptions(Req*);
+void proto(Req*, int);
+void rcvdecline(Req*);
+void rcvdiscover(Req*);
+void rcvinform(Req*);
+void rcvrelease(Req*);
+void rcvrequest(Req*);
+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 logdhcp(Req*);
+void logdhcpout(Req *, char *);
+int readlast(int, Udphdr*, uchar*, int);
+
+void
+timestamp(char *tag)
+{
+ ulong t;
+
+ t = nsec()/1000;
+ syslog(0, blog, "%s %lud", tag, t - start);
+}
+
+void
+usage(void)
+{
+ fprint(2, "usage: dhcp [-dmsnp] [-f directory] [-x netmtpt] [-M minlease] addr n [addr n ...]\n");
+ exits("usage");
+}
+
+void
+main(int argc, char **argv)
+{
+ int i, n, fd;
+ char *p;
+ uchar ip[IPaddrlen];
+ Req r;
+
+ fmtinstall('E', eipfmt);
+ fmtinstall('I', eipfmt);
+ fmtinstall('V', eipfmt);
+ fmtinstall('M', eipfmt);
+ ARGBEGIN {
+ case 'm':
+ mute = 1;
+ break;
+ case 'd':
+ debug = 1;
+ break;
+ case 'f':
+ p = ARGF();
+ if(p == nil)
+ usage();
+ ndbfile = p;
+ break;
+ case 's':
+ slow = 1;
+ break;
+ case 'n':
+ nobootp = 1;
+ break;
+ case 'i':
+ parseip(xmyipaddr,EARGF(usage()));
+ break;
+ case 'p':
+ pptponly = 1;
+ break;
+ case 'M':
+ p = ARGF();
+ if(p == nil)
+ usage();
+ minlease = atoi(p);
+ if(minlease <= 0)
+ minlease = MinLease;
+ 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? */
+ p = readsysname();
+ strcpy(mysysname, p);
+
+ /* put process in background */
+ if(!debug) switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
+ case -1:
+ fatal(1, "fork");
+ case 0:
+ break;
+ default:
+ exits(0);
+ }
+
+ chdir(TFTP);
+ fd = openlisten(net);
+ wfd = fd;
+ bwfd = fd;
+ if(setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", 5) < 0)
+ print("setsockopt: %r\n");
+
+ for(;;){
+ memset(&r, 0, sizeof(r));
+ r.fd = fd;
+ n = readlast(fd, &r.uh, r.buf, sizeof(r.buf));
+ if(n < 0)
+ 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 = &rp->uh;
+ rp->max = rp->buf + 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, xmyipaddr);
+ ipmove(rp->up->laddr, xmyipaddr);
+ 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");
+}
+
+void
+dhcp(Req *rp)
+{
+ logdhcp(rp);
+
+ switch(rp->dhcptype){
+ case Discover:
+ if(slow)
+ sleep(500);
+ 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);
+ 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, 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, 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 for",
+ 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, 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;
+ }
+}
+
+void
+sendoffer(Req *rp, uchar *ip, int offer)
+{
+ int n;
+ int fd;
+ ushort flags;
+ Bootp *bp;
+ Udphdr *up;
+
+ bp = rp->bp;
+ up = rp->up;
+
+ /*
+ * set destination
+ */
+ flags = nhgets(bp->flags);
+ fd = wfd;
+ if(validip(rp->giaddr)){
+ ipmove(up->raddr, rp->giaddr);
+ hnputs(up->rport, 67);
+ } else if(flags & Fbroadcast){
+ fd = bwfd;
+ 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;
+print("OFFER: %I %I %d %d\n", rp->up->laddr, rp->up->raddr, nhgets(rp->up->lport), nhgets(rp->up->rport));
+ if(!mute && udpwrite(fd, rp->up, rp->buf, n) != n)
+ warning(0, "offer: write failed: %r");
+}
+
+void
+sendack(Req *rp, uchar *ip, int offer, int sendlease)
+{
+ int n, fd;
+ ushort flags;
+ Bootp *bp;
+ Udphdr *up;
+
+ bp = rp->bp;
+ up = rp->up;
+
+ /*
+ * set destination
+ */
+ fd = wfd;
+ flags = nhgets(bp->flags);
+ if(validip(rp->giaddr)){
+ ipmove(up->raddr, rp->giaddr);
+ hnputs(up->rport, 67);
+ } else if(flags & Fbroadcast){
+ fd = bwfd;
+ 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(!mute && udpwrite(fd, rp->up, rp->buf, n) != n)
+ warning(0, "ack: write failed: %r");
+}
+
+void
+sendnak(Req *rp, char *msg)
+{
+ int n, fd;
+ Bootp *bp;
+ Udphdr *up;
+
+ bp = rp->bp;
+ up = rp->up;
+
+ /*
+ * set destination (always broadcast)
+ */
+ fd = wfd;
+ if(validip(rp->giaddr)){
+ ipmove(up->raddr, rp->giaddr);
+ hnputs(up->rport, 67);
+ } else {
+ fd = bwfd;
+ 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(!mute && udpwrite(fd, rp->up, rp->buf, n) != n)
+ warning(0, "nak: write failed: %r");
+}
+
+void
+bootp(Req *rp)
+{
+ int n, fd;
+ 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 if(slow)
+ sleep(500);
+
+ /* ignore if we don't know what file to load */
+ if(*bp->file == 0){
+ if(rp->genrequest && *iip->bootf2) /* if not plan 9 and we have an 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
+ */
+ fd = wfd;
+ flags = nhgets(bp->flags);
+ if(validip(rp->giaddr)){
+ ipmove(up->raddr, rp->giaddr);
+ hnputs(up->rport, 67);
+ } else if(flags & Fbroadcast){
+ fd = bwfd;
+ 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(!mute && udpwrite(fd, rp->up, 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;
+ 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)
+{
+ char *p;
+ int i, j;
+ uchar *addrs[2];
+ uchar x[2*IPaddrlen];
+ uchar vopts[64];
+ uchar *op, *omax;
+ char *attr[100], **a;
+ int na;
+ 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;
+ rp->p = vopts;
+ rp->max = vopts + sizeof(vopts) - 1;
+
+ j = lookupserver("fs", addrs, t);
+ addrsopt(rp, OP9fs, addrs, j);
+ j = lookupserver("auth", addrs, t);
+ addrsopt(rp, OP9auth, addrs, j);
+
+ // point back
+ j = rp->p - vopts;
+ rp->p = op;
+ rp->max = omax;
+ vectoropt(rp, OBvendorinfo, vopts, j);
+ }
+
+ ndbfree(t);
+}
+
+int
+openlisten(char *net)
+{
+ int fd;
+ char data[128];
+ char devdir[40];
+ int yes;
+
+ sprint(data, "udp!*!bootps");
+ fd = announce(data, devdir);
+ if(fd < 0)
+ fatal(1, "can't announce");
+ yes = 1;
+ if(setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &yes, sizeof yes) < 0)
+ fatal(1, "can't broadcast");
+ return fd;
+}
+
+void
+fatal(int syserr, char *fmt, ...)
+{
+ char buf[ERRMAX];
+ 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);
+}
+
+extern void
+warning(int syserr, char *fmt, ...)
+{
+ char buf[256];
+ 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;
+ *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)
+{
+ if(i <= 0)
+ return;
+ if(rp->p + 2 + 4*i > rp->max)
+ return;
+ *rp->p++ = t;
+ *rp->p++ = 4*i;
+ op = seprint(op, oe, "%s(", optname[t]);
+ while(i-- > 0){
+ 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
+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;
+ 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", 0);
+ for(i = 1; i < n; i++)
+ op = seprint(op, oe, " %ud", v[i]);
+}
+
+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);
+}
+
+/*
+ * What a crock it is to do this for real.
+ * A giant hairy mess of ioctls that differ from
+ * system to system. Don't get sucked in.
+ * This need not be fast.
+ */
+void
+arpenter(uchar *ip, uchar *ether)
+{
+ int pid;
+ char xip[100], xether[100];
+
+ switch(pid=fork()){
+ case -1:
+ break;
+ default:
+ waitpid();
+ break;
+ case 0:
+ snprint(xip, sizeof xip, "%I", ip);
+ snprint(xether, sizeof xether, "%#E", ether);
+ execl("arp", "arp", "-s", xip, xether, "temp", nil);
+ _exits("execl");
+ }
+/*
+ for comfort - ah, the good old days
+
+ 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 the last message in the queue.
+ */
+void ding(void *x, char *msg)
+{
+ USED(x);
+
+ if(strstr(msg, "alarm"))
+ noted(NCONT);
+ else
+ noted(NDFLT);
+}
+
+int
+readlast(int fd, Udphdr *hdr, uchar *buf, int len)
+{
+ int lastn, n;
+
+ notify(ding);
+
+ lastn = 0;
+ for(;;){
+ alarm(20);
+ n = udpread(fd, hdr, buf, len);
+ alarm(0);
+ if(n < 0){
+ if(lastn > 0)
+ return lastn;
+ break;
+ }
+ lastn = n;
+ }
+ return udpread(fd, hdr, buf, len);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-02 21:43:42 +0000