implement Ether; include "sys.m";	sys: Sys; include "ether.m"; init(){	sys = load Sys Sys->PATH;} parse(s: string): array of byte{	a := array[Eaddrlen] of byte;	for(i := 0; i < len a; i++){		n: int;		(n, s) = hex(s);		if(n < 0){			sys->werrstr("invalid ether address");			return nil;		}		a[i] = byte n;		if(s != nil && s[0] == ':')			s = s[1:];	}	return a;} hex(s: string): (int, string){	n := 0;	for(i := 0; i < len s && i < 2; i++){		if((c := s[i]) >= '0' && c <= '9')			c -= '0';		else if(c >= 'a' && c <= 'f')			c += 10 - 'a';		else if(c >= 'A' && c <= 'F')			c += 10 - 'A';		else if(c == ':')			break;		else			return (-1, s);		n = (n<<4) | c;	}	if(i == 0)		return (-1, s);	return (n, s[i:]);} text(a: array of byte): string{	if(len a < Eaddrlen)		return "<invalid>";	return sys->sprint("%.2ux%.2ux%.2ux%.2ux%.2ux%.2ux",		int a[0], int a[1], int a[2], int a[3], int a[4], int a[5]);} addressof(dev: string): array of byte{	if(dev != nil && dev[0] != '/')		dev = "/net/"+dev;	fd := sys->open(dev+"/addr", Sys->OREAD);	if(fd == nil)		return nil;	buf := array[64] of byte;	n := sys->read(fd, buf, len buf);	if(n <= 0)		return nil;	if(n > 0 && buf[n-1] == byte '\n')		n--;	return parse(string buf[0:n]);} eqaddr(a: array of byte, b: array of byte): int{	if(len a != len b)		return 0;	for(i := 0; i < len a; i++)		if(a[i] != b[i])			return 0;	return 1;}