Here is all available options for SOL_SOCKET.
For example, after creating your socket with
$sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname("tcp"));
$opt=array(
SO_BROADCAST,
SO_DONTROUTE,
SO_DEBUG,
SO_ERROR,
SO_FREE,
SO_KEEPALIVE,
SO_LINGER,
SO_NOSERVER,
SO_OOBINLINE,
SO_RCVBUF,
SO_RCVLOWAT,
SO_RCVTIMEO,
SO_REUSEADDR,
SO_SNDBUF,
SO_SNDLOWAT,
SO_SNDTIMEO,
SO_TYPE);
foreach ($opt as $value) {
var_dump(socket_get_option($sock, SOL_SOCKET, $value));
}