ref: bd773dee09460f5d77c96f2fe3d34ec5ee0b54ce
dir: /sys/src/cmd/ip/ipconfig/dhcpv6.c/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ip.h>
#include <ndb.h>
#include "ipconfig.h"
enum {
SOLICIT = 1,
ADVERTISE,
REQUEST,
CONFIRM,
RENEW,
REBIND,
REPLY,
RELEASE,
DECLINE,
RECONFIGURE,
INFOREQ,
RELAYFORW,
RELAYREPL,
};
static uchar v6dhcpservers[IPaddrlen] = {
0xff, 0x02, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 1, 0, 2,
};
static uchar sid[256];
static int sidlen;
static int
openlisten(void)
{
int n, fd, cfd;
char data[128], devdir[40];
snprint(data, sizeof(data), "%s/udp!%I!546", conf.mpoint, conf.lladdr);
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");
fprint(cfd, "ignoreadvice");
snprint(data, sizeof(data), "%s/data", devdir);
fd = open(data, ORDWR);
if(fd < 0)
sysfatal("open %s: %r", data);
close(cfd);
return fd;
}
static int
findopt(int id, uchar **sp, uchar *e)
{
uchar *p;
int opt;
int len;
p = *sp;
while(p + 4 <= e) {
opt = (int)p[0] << 8 | p[1];
len = (int)p[2] << 8 | p[3];
p += 4;
if(p + len > e)
break;
if(opt == id){
*sp = p;
return len;
}
p += len;
}
return -1;
}
static int
badstatus(int type, int opt, uchar *p, uchar *e)
{
int len, status;
len = findopt(13, &p, e);
if(len < 0)
return 0;
if(len < 2)
return 1;
status = (int)p[0] << 8 | p[1];
if(status == 0)
return 0;
warning("dhcpv6: bad status in request/response type %x, option %d, status %d: %.*s",
type, opt, status, len - 2, (char*)p + 2);
return status;
}
static int
transaction(int fd, int type, int irt, int retrans, int timeout)
{
union {
Udphdr;
uchar buf[4096];
} ipkt, opkt;
int tra, opt, len, status, sleepfor, jitter;
uchar *p, *e, *x;
ulong t1, apflt;
conf.lease = ~0UL; /* infinity */
tra = lrand() & 0xFFFFFF;
ipmove(opkt.laddr, conf.lladdr);
ipmove(opkt.raddr, v6dhcpservers);
ipmove(opkt.ifcaddr, conf.lladdr);
hnputs(opkt.lport, 546);
hnputs(opkt.rport, 547);
p = opkt.buf + Udphdrsize;
*p++ = type;
*p++ = tra >> 16;
*p++ = tra >> 8;
*p++ = tra >> 0;
/* client identifier */
*p++ = 0x00; *p++ = 0x01;
/* len */
*p++ = conf.duidlen >> 8;
*p++ = conf.duidlen;
memmove(p, conf.duid, conf.duidlen);
p += conf.duidlen;
/* IA for non-temporary address */
len = 12;
if(validv6prefix(conf.laddr))
len += 4 + IPaddrlen+2*4;
*p++ = 0x00; *p++ = 0x03;
*p++ = len >> 8;
*p++ = len;
/* IAID */
*p++ = 0x00; *p++ = 0x00; *p++ = 0x00; *p++ = 0x01;
/* T1, T2 */
*p++ = 0x00; *p++ = 0x00; *p++ = 0x00; *p++ = 0x00;
*p++ = 0x00; *p++ = 0x00; *p++ = 0x00; *p++ = 0x00;
if(len > 12){
*p++ = 0x00; *p++ = 0x05;
*p++ = 0x00; *p++ = IPaddrlen+2*4;
memmove(p, conf.laddr, IPaddrlen);
p += IPaddrlen;
memset(p, 0xFF, 2*4);
p += 2*4;
}
/* IA for prefix delegation */
len = 12;
if(validv6prefix(conf.v6pref))
len += 4 + 2*4+1+IPaddrlen;
*p++ = 0x00; *p++ = 0x19;
*p++ = len >> 8;
*p++ = len;
/* IAID */
*p++ = 0x00; *p++ = 0x00; *p++ = 0x00; *p++ = 0x02; /* lies */
/* T1, T2 */
*p++ = 0x00; *p++ = 0x00; *p++ = 0x00; *p++ = 0x00;
*p++ = 0x00; *p++ = 0x00; *p++ = 0x00; *p++ = 0x00;
if(len > 12){
*p++ = 0x00; *p++ = 0x1a;
*p++ = 0x00; *p++ = 2*4+1+IPaddrlen;
*p++ = conf.preflt >> 24;
*p++ = conf.preflt >> 16;
*p++ = conf.preflt >> 8;
*p++ = conf.preflt;
*p++ = conf.validlt >> 24;
*p++ = conf.validlt >> 16;
*p++ = conf.validlt >> 8;
*p++ = conf.validlt;
*p++ = conf.prefixlen;
ipmove(p, conf.v6pref);
p += IPaddrlen;
}
/* Option Request */
*p++ = 0x00; *p++ = 0x06;
*p++ = 0x00; *p++ = 0x02;
*p++ = 0x00; *p++ = 0x17; /* DNS servers */
/* server identifier */
if(sidlen > 0
&& type != SOLICIT && type != CONFIRM && type != REBIND){
*p++ = 0x00; *p++ = 0x02;
/* len */
*p++ = sidlen >> 8;
*p++ = sidlen;;
memmove(p, sid, sidlen);
p += sidlen;
}
len = -1;
for(sleepfor = irt; timeout > 0; sleepfor <<= 1){
DEBUG("sending dhcpv6 request %x", opkt.buf[Udphdrsize]);
jitter = sleepfor / 10;
if(jitter > 1)
sleepfor += nrand(jitter);
alarm(sleepfor);
if(len < 0)
write(fd, opkt.buf, p - opkt.buf);
len = read(fd, ipkt.buf, sizeof(ipkt.buf));
timeout += alarm(0);
timeout -= sleepfor;
if(len == 0)
break;
if(len < 0){
if(--retrans == 0)
break;
continue;
}
if(len < Udphdrsize+4)
continue;
if(ipkt.buf[Udphdrsize+1] != ((tra>>16)&0xFF)
|| ipkt.buf[Udphdrsize+2] != ((tra>>8)&0xFF)
|| ipkt.buf[Udphdrsize+3] != ((tra>>0)&0xFF))
continue;
DEBUG("got dhcpv6 reply %x from %I on %I", ipkt.buf[Udphdrsize+0], ipkt.raddr, ipkt.ifcaddr);
type |= (int)ipkt.buf[Udphdrsize+0]<<8;
switch(type){
case ADVERTISE << 8 | SOLICIT:
case REPLY << 8 | REQUEST:
case REPLY << 8 | RENEW:
case REPLY << 8 | REBIND:
goto Response;
default:
return -1;
}
}
return -1;
Response:
for(p = ipkt.buf + Udphdrsize + 4, e = ipkt.buf + len; p < e; p = x) {
if (p+4 > e)
return -1;
opt = (int)p[0] << 8 | p[1];
len = (int)p[2] << 8 | p[3];
p += 4;
x = p+len;
if (x > e)
return -1;
DEBUG("got dhcpv6 option %d: [%d] %.*H", opt, len, len, p);
switch(opt){
case 1: /* client identifier */
continue;
case 2: /* server identifier */
if(len < 1 || len > sizeof(sid))
break;
sidlen = len;
memmove(sid, p, sidlen);
continue;
case 3: /* IA for non-temporary address */
if(p+12 > x)
break;
t1 = (ulong)p[4] << 24 |
(ulong)p[5] << 16 |
(ulong)p[6] << 8 |
(ulong)p[7];
/* skip IAID, T1, T2 */
p += 12;
status = badstatus(type, opt, p, x);
if(status != 0)
return -status;
/* IA Addresss */
if(findopt(5, &p, x) < IPaddrlen + 2*4)
break;
ipmove(conf.laddr, p);
memset(conf.mask, 0xFF, IPaddrlen);
p += IPaddrlen;
/* preferred lifetime of IA Address */
apflt = (ulong)p[0] << 24 |
(ulong)p[1] << 16 |
(ulong)p[2] << 8 |
(ulong)p[3];
/* adjust lease */
if(t1 != 0 && t1 < conf.lease)
conf.lease = t1;
if(apflt != 0 && apflt < conf.lease)
conf.lease = apflt;
continue;
case 13: /* status */
status = badstatus(type, opt, p - 4, x);
if(status != 0)
return -status;
continue;
case 23: /* dns servers */
if(len % IPaddrlen)
break;
addaddrs(conf.dns, sizeof(conf.dns), p, len);
continue;
case 25: /* IA for prefix delegation */
if(p+12 > x)
break;
t1 = (ulong)p[4] << 24 |
(ulong)p[5] << 16 |
(ulong)p[6] << 8 |
(ulong)p[7];
/* skip IAID, T1, T2 */
p += 12;
status = badstatus(type, opt, p, x);
if(status != 0){
if(type == (ADVERTISE << 8 | SOLICIT))
continue;
return -status;
}
/* IA Prefix */
if(findopt(26, &p, x) < 2*4+1+IPaddrlen)
break;
conf.preflt = (ulong)p[0] << 24 |
(ulong)p[1] << 16 |
(ulong)p[2] << 8 |
(ulong)p[3];
conf.validlt = (ulong)p[4] << 24 |
(ulong)p[5] << 16 |
(ulong)p[6] << 8 |
(ulong)p[7];
p += 8;
if(conf.preflt > conf.validlt)
break;
conf.prefixlen = *p++ & 127;
genipmask(conf.v6mask, conf.prefixlen);
maskip(p, conf.v6mask, conf.v6pref);
/* adjust lease */
if(t1 != 0 && t1 < conf.lease)
conf.lease = t1;
if(conf.preflt != 0 && conf.preflt < conf.lease)
conf.lease = conf.preflt;
continue;
default:
DEBUG("unknown dhcpv6 option: %d", opt);
continue;
}
warning("dhcpv6: malformed option %d: [%d] %.*H", opt, len, len, x-len);
}
return 0;
}
int
dhcpv6query(int renew)
{
int fd;
if(!renew){
ipmove(conf.laddr, IPnoaddr);
ipmove(conf.v6pref, IPnoaddr);
ipmove(conf.v6mask, IPnoaddr);
conf.prefixlen = 0;
conf.preflt = 0;
conf.validlt = 0;
conf.autoflag = 0;
conf.onlink = 0;
}
if(conf.duidlen <= 0)
return -1;
fd = openlisten();
if(fd < 0)
return -1;
if(renew){
if(!validv6prefix(conf.laddr))
goto fail;
/*
* the standard says 600 seconds for maxtimeout,
* but this seems ridiculous. better start over.
*/
if(transaction(fd, RENEW, 10*1000, 0, 30*1000) < 0){
if(!validv6prefix(conf.laddr))
goto fail;
if(transaction(fd, REBIND, 10*1000, 0, 30*1000) < 0)
goto fail;
}
} else {
/*
* the standard says SOL_MAX_RT is 3600 seconds,
* but it is better to fail quickly here and wait
* for the next router advertisement.
*/
if(transaction(fd, SOLICIT, 1000, 0, 10*1000) < 0)
goto fail;
if(!validv6prefix(conf.laddr))
goto fail;
if(transaction(fd, REQUEST, 1000, 10, 30*1000) < 0)
goto fail;
}
if(!validv6prefix(conf.laddr))
goto fail;
close(fd);
return 0;
fail:
close(fd);
return -1;
}