Subversion Repositories planix.SVN

/*
 * 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);
}