ref: eb73718c25eede77fa970c837f6c000d84ca8f55
dir: /sys/src/cmd/ip/ipconfig/dhcp.c/
/*
* ipconfig - configure parameters of an ip stack
*/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ip.h>
#include <ndb.h>
#include "ipconfig.h"
#include "../dhcp.h"
enum
{
Taddr,
Taddrs,
Tstr,
Tbyte,
Tulong,
Tvec,
Tnames,
};
typedef struct Option Option;
struct Option
{
char *name;
int type;
};
/*
* I was too lazy to look up the types for each of these
* options. If someone feels like it, please mail me a
* corrected array -- presotto
*/
static Option option[256] =
{
[OBmask] { "ipmask", Taddr },
[OBtimeoff] { "timeoff", Tulong },
[OBrouter] { "ipgw", Taddrs },
[OBtimeserver] { "time", Taddrs },
[OBnameserver] { "name", Taddrs },
[OBdnserver] { "dns", Taddrs },
[OBlogserver] { "log", Taddrs },
[OBcookieserver] { "cookie", Taddrs },
[OBlprserver] { "lpr", Taddrs },
[OBimpressserver] { "impress", Taddrs },
[OBrlserver] { "rl", Taddrs },
[OBhostname] { "sys", Tstr },
[OBbflen] { "bflen", Tulong },
[OBdumpfile] { "dumpfile", Tstr },
[OBdomainname] { "dom", Tstr },
[OBrootserver] { "rootserver", Taddrs },
[OBrootpath] { "rootpath", Tstr },
[OBextpath] { "extpath", Tstr },
[OBipforward] { "ipforward", Taddrs },
[OBnonlocal] { "nonlocal", Taddrs },
[OBpolicyfilter] { "policyfilter", Taddrs },
[OBmaxdatagram] { "maxdatagram", Tulong },
[OBttl] { "ttl", Tulong },
[OBpathtimeout] { "pathtimeout", Taddrs },
[OBpathplateau] { "pathplateau", Taddrs },
[OBmtu] { "mtu", Tulong },
[OBsubnetslocal] { "subnetslocal", Taddrs },
[OBbaddr] { "baddr", Taddrs },
[OBdiscovermask] { "discovermask", Taddrs },
[OBsupplymask] { "supplymask", Taddrs },
[OBdiscoverrouter] { "discoverrouter", Taddrs },
[OBrsserver] { "rs", Taddrs },
[OBstaticroutes] { "staticroutes", Taddrs },
[OBtrailerencap] { "trailerencap", Taddrs },
[OBarptimeout] { "arptimeout", Tulong },
[OBetherencap] { "etherencap", Taddrs },
[OBtcpttl] { "tcpttl", Tulong },
[OBtcpka] { "tcpka", Tulong },
[OBtcpkag] { "tcpkag", Tulong },
[OBnisdomain] { "nisdomain", Tstr },
[OBniserver] { "ni", Taddrs },
[OBntpserver] { "ntp", Taddrs },
[OBnetbiosns] { "netbiosns", Taddrs },
[OBnetbiosdds] { "netbiosdds", Taddrs },
[OBnetbiostype] { "netbiostype", Taddrs },
[OBnetbiosscope] { "netbiosscope", Taddrs },
[OBxfontserver] { "xfont", Taddrs },
[OBxdispmanager] { "xdispmanager", Taddrs },
[OBnisplusdomain] { "nisplusdomain", Tstr },
[OBnisplusserver] { "nisplus", Taddrs },
[OBhomeagent] { "homeagent", Taddrs },
[OBsmtpserver] { "smtp", Taddrs },
[OBpop3server] { "pop3", Taddrs },
[OBnntpserver] { "nntp", Taddrs },
[OBwwwserver] { "www", Taddrs },
[OBfingerserver] { "finger", Taddrs },
[OBircserver] { "irc", Taddrs },
[OBstserver] { "st", Taddrs },
[OBstdaserver] { "stdar", Taddrs },
[ODipaddr] { "ipaddr", Taddr },
[ODlease] { "lease", Tulong },
[ODoverload] { "overload", Taddr },
[ODtype] { "type", Tbyte },
[ODserverid] { "serverid", Taddr },
[ODparams] { "params", Tvec },
[ODmessage] { "message", Tstr },
[ODmaxmsg] { "maxmsg", Tulong },
[ODrenewaltime] { "renewaltime", Tulong },
[ODrebindingtime] { "rebindingtime", Tulong },
[ODvendorclass] { "vendorclass", Tvec },
[ODclientid] { "clientid", Tvec },
[ODtftpserver] { "tftp", Taddr },
[ODbootfile] { "bootfile", Tstr },
[ODdnsdomain] { "dnsdomain", Tnames },
};
static uchar defrequested[] = {
OBmask, OBrouter, OBdnserver, OBhostname, OBdomainname, ODdnsdomain, OBntpserver,
};
static uchar requested[256];
static int nrequested;
static char optmagic[4] = { 0x63, 0x82, 0x53, 0x63 };
static int openlisten(void);
static void dhcprecv(void);
static void dhcpsend(int);
static void dhcptimer(void);
static uchar* optaddaddr(uchar*, int, uchar*);
static uchar* optaddbyte(uchar*, int, int);
static uchar* optaddstr(uchar*, int, char*);
static uchar* optadd(uchar*, int, void*, int);
static uchar* optaddulong(uchar*, int, ulong);
static uchar* optaddvec(uchar*, int, uchar*, int);
static int optgetaddrs(uchar*, int, uchar*, int);
static int optgetp9addrs(uchar*, int, uchar*, int);
static int optgetaddr(uchar*, int, uchar*);
static int optgetbyte(uchar*, int);
static int optgetstr(uchar*, int, char*, int);
static uchar* optget(uchar*, int, int*);
static ulong optgetulong(uchar*, int);
static int optgetvec(uchar*, int, uchar*, int);
static char* optgetx(uchar*, uchar);
static int optgetnames(uchar*, int, char*, int);
static void getoptions(uchar*);
static int parseoptions(uchar *p, int n);
static Bootp* parsebootp(uchar*, int);
void
dhcpinit(void)
{
/* init set of requested dhcp parameters with the default */
nrequested = sizeof defrequested;
memcpy(requested, defrequested, nrequested);
}
static void
removenulladdr(void)
{
fprint(conf.cfd, "remove %I %M", IPnoaddr, IPnoaddr);
atexitdont(removenulladdr);
}
static void
addnulladdr(void)
{
atexit(removenulladdr);
fprint(conf.cfd, "add %I %M", IPnoaddr, IPnoaddr);
}
void
dhcpquery(int needconfig, int startstate)
{
if(needconfig)
addnulladdr();
conf.fd = openlisten();
if(conf.fd < 0){
conf.state = Sinit;
return;
}
notify(catch);
conf.xid = lrand();
conf.starttime = time(0);
conf.state = startstate;
switch(startstate){
case Sselecting:
conf.offered = 0;
dhcpsend(Discover);
break;
case Srenewing:
dhcpsend(Request);
break;
default:
sysfatal("internal error 0");
}
conf.resend = 0;
conf.timeout = time(0) + 4;
while(conf.state != Sbound && conf.state != Sinit){
dhcprecv();
dhcptimer();
}
close(conf.fd);
if(needconfig)
removenulladdr();
}
enum {
/*
* was an hour, needs to be less for the ARM/GS1 until the timer
* code has been cleaned up (pb).
*/
Maxsleep = 450,
};
void
dhcpwatch(int needconfig)
{
ulong secs, s, t;
if(nodhcpwatch)
return;
switch(rfork(RFPROC|RFFDG|RFNOWAIT|RFNOTEG)){
default:
return;
case 0:
break;
}
dolog = 1; /* log, don't print */
procsetname("dhcpwatch on %s", conf.dev);
/* keep trying to renew the lease */
for(;;){
secs = conf.lease/2;
if(secs < 5)
secs = 5;
/* avoid overflows */
for(s = secs; s > 0; s -= t){
if(s > Maxsleep)
t = Maxsleep;
else
t = s;
sleep(t*1000);
}
if(conf.lease > 0){
/*
* during boot, the starttime can be bogus so avoid
* spurious ipunconfig's
*/
t = time(0) - conf.starttime;
if(t > (3*secs)/2)
t = secs;
if(t >= conf.lease){
conf.lease = 0;
DEBUG("couldn't renew IP lease");
if(!noconfig){
ipunconfig();
needconfig = 1;
}
} else
conf.lease -= t;
}
dhcpquery(needconfig, needconfig? Sselecting: Srenewing);
if(needconfig && conf.state == Sbound){
if(ip4cfg() < 0)
sysfatal("can't start ip: %r");
needconfig = 0;
/*
* leave everything we've learned somewhere that
* other procs can find it.
*/
putndb();
refresh();
}
}
}
static void
dhcptimer(void)
{
ulong now;
now = time(0);
if(now < conf.timeout)
return;
switch(conf.state) {
default:
sysfatal("dhcptimer: unknown state %d", conf.state);
case Sinit:
case Sbound:
break;
case Sselecting:
case Srequesting:
case Srebinding:
dhcpsend(conf.state == Sselecting? Discover: Request);
conf.timeout = now + 4;
if(++conf.resend > 5)
conf.state = Sinit;
break;
case Srenewing:
dhcpsend(Request);
conf.timeout = now + 1;
if(++conf.resend > 3) {
conf.state = Srebinding;
conf.resend = 0;
}
break;
}
}
static void
dhcpsend(int type)
{
Bootp bp;
uchar *p;
int n;
uchar vendor[64];
Udphdr *up = (Udphdr*)bp.udphdr;
memset(&bp, 0, sizeof bp);
hnputs(up->rport, 67);
bp.op = Bootrequest;
hnputl(bp.xid, conf.xid);
hnputs(bp.secs, time(0)-conf.starttime);
hnputs(bp.flags, 0);
memmove(bp.optmagic, optmagic, 4);
if(conf.hwatype >= 0 && conf.hwalen < sizeof bp.chaddr){
memmove(bp.chaddr, conf.hwa, conf.hwalen);
bp.hlen = conf.hwalen;
bp.htype = conf.hwatype;
}
p = bp.optdata;
p = optaddbyte(p, ODtype, type);
p = optadd(p, ODclientid, conf.cid, conf.cidlen);
switch(type) {
default:
sysfatal("dhcpsend: unknown message type: %d", type);
case Discover:
ipmove(up->raddr, IPv4bcast); /* broadcast */
if(*conf.hostname && sendhostname)
p = optaddstr(p, OBhostname, conf.hostname);
if(plan9){
n = snprint((char*)vendor, sizeof vendor,
"plan9_%s", conf.cputype);
p = optaddvec(p, ODvendorclass, vendor, n);
}
p = optaddvec(p, ODparams, requested, nrequested);
if(validip(conf.laddr))
p = optaddaddr(p, ODipaddr, conf.laddr);
break;
case Request:
switch(conf.state){
case Srenewing:
ipmove(up->raddr, conf.server);
v6tov4(bp.ciaddr, conf.laddr);
break;
case Srebinding:
ipmove(up->raddr, IPv4bcast); /* broadcast */
v6tov4(bp.ciaddr, conf.laddr);
break;
case Srequesting:
ipmove(up->raddr, IPv4bcast); /* broadcast */
p = optaddaddr(p, ODipaddr, conf.laddr);
p = optaddaddr(p, ODserverid, conf.server);
break;
}
p = optaddulong(p, ODlease, conf.offered);
if(plan9){
n = snprint((char*)vendor, sizeof vendor,
"plan9_%s", conf.cputype);
p = optaddvec(p, ODvendorclass, vendor, n);
}
p = optaddvec(p, ODparams, requested, nrequested);
if(*conf.hostname && sendhostname)
p = optaddstr(p, OBhostname, conf.hostname);
break;
case Release:
ipmove(up->raddr, conf.server);
v6tov4(bp.ciaddr, conf.laddr);
p = optaddaddr(p, ODipaddr, conf.laddr);
p = optaddaddr(p, ODserverid, conf.server);
break;
}
*p++ = OBend;
n = p - (uchar*)&bp;
USED(n);
/*
* We use a maximum size DHCP packet to survive the
* All_Aboard NAT package from Internet Share. It
* always replies to DHCP requests with a packet of the
* same size, so if the request is too short the reply
* is truncated.
*/
if(write(conf.fd, &bp, sizeof bp) != sizeof bp)
warning("dhcpsend: write failed: %r");
}
static void
dhcprecv(void)
{
int i, n, type;
ulong lease;
char err[ERRMAX];
uchar buf[8000], vopts[256], taddr[IPaddrlen];
Bootp *bp;
memset(buf, 0, sizeof buf);
alarm(1000);
n = read(conf.fd, buf, sizeof buf);
alarm(0);
if(n < 0){
rerrstr(err, sizeof err);
if(strstr(err, "interrupt") == nil)
warning("dhcprecv: bad read: %s", err);
else
DEBUG("dhcprecv: read timed out");
return;
}
bp = parsebootp(buf, n);
if(bp == 0) {
DEBUG("parsebootp failed: dropping packet");
return;
}
type = optgetbyte(bp->optdata, ODtype);
switch(type) {
default:
warning("dhcprecv: unknown type: %d", type);
break;
case Offer:
DEBUG("got offer from %V ", bp->siaddr);
if(conf.state != Sselecting)
break;
lease = optgetulong(bp->optdata, ODlease);
if(lease == 0){
/*
* The All_Aboard NAT package from Internet Share
* doesn't give a lease time, so we have to assume one.
*/
warning("Offer with %lud lease, using %d", lease, MinLease);
lease = MinLease;
}
DEBUG("lease=%lud ", lease);
if(!optgetaddr(bp->optdata, ODserverid, conf.server)) {
warning("Offer from server with invalid serverid");
break;
}
v4tov6(conf.laddr, bp->yiaddr);
memmove(conf.sname, bp->sname, sizeof conf.sname);
conf.sname[sizeof conf.sname-1] = 0;
DEBUG("server=%I sname=%s", conf.server, conf.sname);
conf.offered = lease;
conf.state = Srequesting;
dhcpsend(Request);
conf.resend = 0;
conf.timeout = time(0) + 4;
break;
case Ack:
DEBUG("got ack from %V ", bp->siaddr);
if (conf.state != Srequesting && conf.state != Srenewing &&
conf.state != Srebinding)
break;
/* ignore a bad lease */
lease = optgetulong(bp->optdata, ODlease);
if(lease == 0){
/*
* The All_Aboard NAT package from Internet Share
* doesn't give a lease time, so we have to assume one.
*/
warning("Ack with %lud lease, using %d", lease, MinLease);
lease = MinLease;
}
DEBUG("lease=%lud ", lease);
/* address and mask */
if(!validip(conf.laddr) || !Oflag)
v4tov6(conf.laddr, bp->yiaddr);
if(!validip(conf.mask) || !Oflag){
if(!optgetaddr(bp->optdata, OBmask, conf.mask))
ipmove(conf.mask, IPnoaddr);
if(ipcmp(conf.mask, IPv4bcast) == 0)
ipmove(conf.mask, IPnoaddr);
}
DEBUG("ipaddr=%I ipmask=%M ", conf.laddr, conf.mask);
/*
* get a router address either from the router option
* or from the router that forwarded the dhcp packet
*/
if(validip(conf.gaddr) && Oflag) {
DEBUG("ipgw=%I ", conf.gaddr);
} else if(optgetaddr(bp->optdata, OBrouter, conf.gaddr)){
DEBUG("ipgw=%I ", conf.gaddr);
} else if(memcmp(bp->giaddr, IPnoaddr+IPv4off, IPv4addrlen)!=0){
v4tov6(conf.gaddr, bp->giaddr);
DEBUG("giaddr=%I ", conf.gaddr);
}
/* get dns servers */
memset(conf.dns, 0, sizeof conf.dns);
n = optgetaddrs(bp->optdata, OBdnserver, conf.dns,
sizeof conf.dns/IPaddrlen);
for(i = 0; i < n; i++)
DEBUG("dns=%I ", conf.dns + i*IPaddrlen);
/* get ntp servers */
memset(conf.ntp, 0, sizeof conf.ntp);
n = optgetaddrs(bp->optdata, OBntpserver, conf.ntp,
sizeof conf.ntp/IPaddrlen);
for(i = 0; i < n; i++)
DEBUG("ntp=%I ", conf.ntp + i*IPaddrlen);
/* get names */
if(optgetstr(bp->optdata, OBhostname,
conf.hostname, sizeof conf.hostname))
DEBUG("hostname=%s ", conf.hostname);
if(optgetstr(bp->optdata, OBdomainname,
conf.domainname, sizeof conf.domainname))
DEBUG("domainname=%s ", conf.domainname);
if(optgetnames(bp->optdata, ODdnsdomain,
conf.dnsdomain, sizeof conf.dnsdomain))
DEBUG("dnsdomain=%s ", conf.dnsdomain);
/* get anything else we asked for */
getoptions(bp->optdata);
/* get plan9-specific options */
n = optgetvec(bp->optdata, OBvendorinfo, vopts, sizeof vopts-1);
if(n > 0 && parseoptions(vopts, n) == 0){
if(validip(conf.fs) && Oflag)
n = 1;
else {
n = optgetp9addrs(vopts, OP9fs, conf.fs, 2);
if (n == 0)
n = optgetaddrs(vopts, OP9fsv4,
conf.fs, 2);
}
for(i = 0; i < n; i++)
DEBUG("fs=%I ", conf.fs + i*IPaddrlen);
if(validip(conf.auth) && Oflag)
n = 1;
else {
n = optgetp9addrs(vopts, OP9auth, conf.auth, 2);
if (n == 0)
n = optgetaddrs(vopts, OP9authv4,
conf.auth, 2);
}
for(i = 0; i < n; i++)
DEBUG("auth=%I ", conf.auth + i*IPaddrlen);
n = optgetp9addrs(vopts, OP9ipaddr, taddr, 1);
if (n > 0)
ipmove(conf.laddr, taddr);
n = optgetp9addrs(vopts, OP9ipmask, taddr, 1);
if (n > 0)
ipmove(conf.mask, taddr);
n = optgetp9addrs(vopts, OP9ipgw, taddr, 1);
if (n > 0)
ipmove(conf.gaddr, taddr);
DEBUG("new ipaddr=%I new ipmask=%M new ipgw=%I",
conf.laddr, conf.mask, conf.gaddr);
}
conf.lease = lease;
conf.state = Sbound;
DEBUG("server=%I sname=%s", conf.server, conf.sname);
break;
case Nak:
conf.state = Sinit;
warning("recved dhcpnak on %s", conf.mpoint);
break;
}
}
static int
openlisten(void)
{
int n, fd, cfd;
char data[128], devdir[40];
if (validip(conf.laddr) &&
(conf.state == Srenewing || conf.state == Srebinding))
sprint(data, "%s/udp!%I!68", conf.mpoint, conf.laddr);
else
sprint(data, "%s/udp!*!68", conf.mpoint);
for (n = 0; (cfd = announce(data, devdir)) < 0; n++) {
if(!noconfig)
sysfatal("can't announce for dhcp: %r");
/* might be another client - wait and try again */
warning("can't announce %s: %r", data);
sleep(jitter());
if(n > 10)
return -1;
}
if(fprint(cfd, "headers") < 0)
sysfatal("can't set header mode: %r");
sprint(data, "%s/data", devdir);
fd = open(data, ORDWR);
if(fd < 0)
sysfatal("open %s: %r", data);
close(cfd);
return fd;
}
static uchar*
optadd(uchar *p, int op, void *d, int n)
{
p[0] = op;
p[1] = n;
memmove(p+2, d, n);
return p+n+2;
}
static uchar*
optaddbyte(uchar *p, int op, int b)
{
p[0] = op;
p[1] = 1;
p[2] = b;
return p+3;
}
static uchar*
optaddulong(uchar *p, int op, ulong x)
{
p[0] = op;
p[1] = 4;
hnputl(p+2, x);
return p+6;
}
static uchar *
optaddaddr(uchar *p, int op, uchar *ip)
{
p[0] = op;
p[1] = 4;
v6tov4(p+2, ip);
return p+6;
}
/* add dhcp option op with value v of length n to dhcp option array p */
static uchar *
optaddvec(uchar *p, int op, uchar *v, int n)
{
p[0] = op;
p[1] = n;
memmove(p+2, v, n);
return p+2+n;
}
static uchar *
optaddstr(uchar *p, int op, char *v)
{
int n;
n = strlen(v);
p[0] = op;
p[1] = n;
memmove(p+2, v, n);
return p+2+n;
}
/*
* parse p, looking for option `op'. if non-nil, np points to minimum length.
* return nil if option is too small, else ptr to opt, and
* store actual length via np if non-nil.
*/
static uchar*
optget(uchar *p, int op, int *np)
{
int len, code;
while ((code = *p++) != OBend) {
if(code == OBpad)
continue;
len = *p++;
if(code != op) {
p += len;
continue;
}
if(np != nil){
if(*np > len)
return 0;
*np = len;
}
return p;
}
return 0;
}
static int
optgetbyte(uchar *p, int op)
{
int len;
len = 1;
p = optget(p, op, &len);
if(p == nil)
return 0;
return *p;
}
static ulong
optgetulong(uchar *p, int op)
{
int len;
len = 4;
p = optget(p, op, &len);
if(p == nil)
return 0;
return nhgetl(p);
}
static int
optgetaddr(uchar *p, int op, uchar *ip)
{
int len;
len = 4;
p = optget(p, op, &len);
if(p == nil)
return 0;
v4tov6(ip, p);
return 1;
}
/* expect at most n addresses; ip[] only has room for that many */
static int
optgetaddrs(uchar *p, int op, uchar *ip, int n)
{
int len, i;
len = 4;
p = optget(p, op, &len);
if(p == nil)
return 0;
len /= IPv4addrlen;
if(len > n)
len = n;
for(i = 0; i < len; i++)
v4tov6(&ip[i*IPaddrlen], &p[i*IPv4addrlen]);
return i;
}
/* expect at most n addresses; ip[] only has room for that many */
static int
optgetp9addrs(uchar *ap, int op, uchar *ip, int n)
{
int len, i, slen, addrs;
char *p;
len = 1; /* minimum bytes needed */
p = (char *)optget(ap, op, &len);
if(p == nil)
return 0;
addrs = *p++; /* first byte is address count */
for (i = 0; i < n && i < addrs && len > 0; i++) {
slen = strlen(p) + 1;
if (parseip(&ip[i*IPaddrlen], p) == -1)
fprint(2, "%s: bad address %s\n", argv0, p);
DEBUG("got plan 9 option %d addr %I (%s)",
op, &ip[i*IPaddrlen], p);
p += slen;
len -= slen;
}
return addrs;
}
static int
optgetvec(uchar *p, int op, uchar *v, int n)
{
int len;
len = 1;
p = optget(p, op, &len);
if(p == nil)
return 0;
if(len > n)
len = n;
memmove(v, p, len);
return len;
}
static int
optgetstr(uchar *p, int op, char *s, int n)
{
int len;
len = 1;
p = optget(p, op, &len);
if(p == nil)
return 0;
if(len >= n)
len = n-1;
memmove(s, p, len);
s[len] = 0;
return len;
}
static int
optgetnames(uchar *p, int op, char *s, int n)
{
uchar buf[256];
int nbuf, len;
for(nbuf=0;;p+=len,nbuf+=len){
len = 1;
p = optget(p, op, &len);
if(p == nil)
break;
if(nbuf+len > sizeof(buf))
return 0;
memmove(buf+nbuf, p, len);
}
if((len = gnames(s, n, buf, nbuf)) < 0){
memset(s, 0, n);
return 0;
}
return len;
}
int
addoption(char *opt)
{
int i;
Option *o;
if(opt == nil)
return -1;
for(o = option; o < &option[nelem(option)]; o++)
if(o->name && strcmp(opt, o->name) == 0){
i = o - option;
if(memchr(requested, i, nrequested) == 0 &&
nrequested < nelem(requested))
requested[nrequested++] = i;
return 0;
}
return -1;
}
static char*
optgetx(uchar *p, uchar opt)
{
int i, n;
ulong x;
char *s, *ns;
char str[256];
uchar ip[IPaddrlen], ips[16*IPaddrlen], vec[256];
Option *o;
o = &option[opt];
if(o->name == nil)
return nil;
s = nil;
switch(o->type){
case Taddr:
if(optgetaddr(p, opt, ip))
s = smprint("%s=%I", o->name, ip);
break;
case Taddrs:
n = optgetaddrs(p, opt, ips, 16);
if(n > 0)
s = smprint("%s=%I", o->name, ips);
for(i = 1; i < n; i++){
ns = smprint("%s %s=%I", s, o->name, &ips[i*IPaddrlen]);
free(s);
s = ns;
}
break;
case Tulong:
x = optgetulong(p, opt);
if(x != 0)
s = smprint("%s=%lud", o->name, x);
break;
case Tbyte:
x = optgetbyte(p, opt);
if(x != 0)
s = smprint("%s=%lud", o->name, x);
break;
case Tstr:
if(optgetstr(p, opt, str, sizeof str))
s = smprint("%s=%s", o->name, str);
break;
case Tvec:
n = optgetvec(p, opt, vec, sizeof vec);
if(n > 0)
s = smprint("%s=%.*H", o->name, n, vec);
break;
}
return s;
}
static void
getoptions(uchar *p)
{
int i;
char *s, *t;
for(i = nelem(defrequested); i < nrequested; i++){
s = optgetx(p, requested[i]);
if(s != nil)
DEBUG("%s ", s);
if(ndboptions == nil)
ndboptions = smprint("\t%s", s);
else{
t = ndboptions;
ndboptions = smprint("\t%s%s", s, ndboptions);
free(t);
}
free(s);
}
}
/*
* sanity check options area
* - options don't overflow packet
* - options end with an OBend
*/
static int
parseoptions(uchar *p, int n)
{
int code, len, nin = n;
while (n > 0) {
code = *p++;
n--;
if(code == OBend)
return 0;
if(code == OBpad)
continue;
if(n == 0) {
warning("parseoptions: bad option: 0x%ux: truncated: "
"opt length = %d", code, nin);
return -1;
}
len = *p++;
n--;
DEBUG("parseoptions: %s(%d) len %d, bytes left %d",
option[code].name, code, len, n);
if(len > n) {
warning("parseoptions: bad option: 0x%ux: %d > %d: "
"opt length = %d", code, len, n, nin);
return -1;
}
p += len;
n -= len;
}
/* make sure packet ends with an OBend after all the optget code */
*p = OBend;
return 0;
}
/*
* sanity check received packet:
* - magic is dhcp magic
* - options don't overflow packet
*/
static Bootp*
parsebootp(uchar *p, int n)
{
Bootp *bp;
bp = (Bootp*)p;
if(n < bp->optmagic - p) {
warning("parsebootp: short bootp packet");
return nil;
}
if(conf.xid != nhgetl(bp->xid)) /* not meant for us */
return nil;
if(bp->op != Bootreply) {
warning("parsebootp: bad op %d", bp->op);
return nil;
}
n -= bp->optmagic - p;
p = bp->optmagic;
if(n < 4) {
warning("parsebootp: no option data");
return nil;
}
if(memcmp(optmagic, p, 4) != 0) {
warning("parsebootp: bad opt magic %ux %ux %ux %ux",
p[0], p[1], p[2], p[3]);
return nil;
}
p += 4;
n -= 4;
DEBUG("parsebootp: new packet");
if(parseoptions(p, n) < 0)
return nil;
return bp;
}