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/*
* linklocal - print ipv6 link-local or 6to4 address of a mac address.
* eui is ieee's extended unique identifier, per rfc2373.
*/
#include <u.h>
#include <libc.h>
#include <ip.h>
enum {
Mac0mcast = 1<<0, /* multicast address */
Mac0localadm = 1<<1, /* locally-administered address, */
V60globaladm = 1<<1, /* but ipv6 reverses the meaning */
};
static char *v4_6to4;
static void
usage(void)
{
fprint(2, "usage: %s [-t ipv4] ether...\n", argv0);
exits("usage");
}
void
ea2eui64(uchar *lla, uchar *ea)
{
*lla++ = *ea++ ^ V60globaladm; /* oui (company id) */
*lla++ = *ea++; /* " */
*lla++ = *ea++; /* " */
*lla++ = 0xFF; /* mac-48 in eui-64 (sic) */
*lla++ = 0xFE; /* " */
*lla++ = *ea++; /* manufacturer-assigned */
*lla++ = *ea++; /* " */
*lla = *ea; /* " */
}
void
eaip26to4(uchar *lla, uchar *ea, uchar *ipv4)
{
*lla++ = 0x20; /* 6to4 address */
*lla++ = 0x02; /* " */
memmove(lla, ipv4, IPv4addrlen);
lla += IPv4addrlen;
memset(lla, 0, 2);
ea2eui64(lla + 2, ea);
}
void
ea2lla(uchar *lla, uchar *ea)
{
*lla++ = 0xFE; /* link-local v6 */
*lla++ = 0x80; /* " */
memset(lla, 0, 6);
ea2eui64(lla + 6, ea);
}
static void
process(char *ether)
{
uchar ethaddr[6], ipaddr[IPaddrlen], ipv4[IPv4addrlen];
if (parseether(ethaddr, ether) < 0)
sysfatal("%s: not an ether address", ether);
if (v4_6to4) {
v4parseip(ipv4, v4_6to4);
eaip26to4(ipaddr, ethaddr, ipv4);
} else
ea2lla(ipaddr, ethaddr);
print("%I\n", ipaddr);
}
void
main(int argc, char *argv[])
{
int i;
ARGBEGIN {
case 't':
v4_6to4 = EARGF(usage());
break;
default:
usage();
break;
} ARGEND
fmtinstall('I', eipfmt);
if (argc <= 0)
usage();
for (i = 0; i < argc; i++)
process(argv[i]);
exits(0);
}
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