ref: 34f5a8333090c5090e1d0b6ddbaf900d64340eea
dir: /sys/src/cmd/ip/linklocal.c/
/* * 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); }