Python socket.IPV6_MULTICAST_LOOP Examples

def _create_ipv6_sockets(loopback_enabled):
    # Open a multicast send socket, with IP_MULTICAST_LOOP enabled or disabled as requested.
    intf_name = find_ethernet_interface()
    intf_index = socket.if_nametoindex(intf_name)
    mcast_address = "ff02::abcd:99"
    port = 30000
    group = (mcast_address, port)
    txsock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    txsock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    txsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_IF, intf_index)
    if loopback_enabled:
        txsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 1)
    else:
        txsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 0)
    txsock.connect(group)
    # Open a multicast receive socket and join the group
    rxsock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    req = struct.pack("=16si", socket.inet_pton(socket.AF_INET6, mcast_address), intf_index)
    if platform.system() == "Darwin":
        rxsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, req)
    else:
        rxsock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_ADD_MEMBERSHIP, req)
    rxsock.bind(("::", port))
    return (txsock, rxsock) 

def _init_advertiser(self):
        sock = _find_sock()
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, struct.pack('@I', 1))
        sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, struct.pack('@I', 1))
        if sock.family == socket.AF_INET6:
            sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, struct.pack('@I', 1))
        sock.bind(('', self.port))

        addrs = _resolve_addrs(self.addresses, None, self.ignore_unavailable, (sock.family,))

        for fam,to,orig_fam,orig_addr in addrs:
            try:
                _multicast_join_group(sock, orig_fam, orig_addr)
            except socket.error:
                if not self.ignore_unavailable:
                    raise

        self._sock = sock 

def create_socket_ipv6_tx_mcast(self, multicast_address, port, loopback):
        if self._interface_index is None:
            self.warning("Could not create IPv6 multicast TX socket: unknown interface index")
            return None
        try:
            sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
        except IOError as err:
            self.warning("Could not create IPv6 UDP socket: %s", err)
            return None
        self.enable_addr_and_port_reuse(sock)
        try:
            sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_IF, self._interface_index)
        except IOError as err:
            self.warning("Could not set IPv6 multicast interface index %d: %s",
                         self._interface_index, err)
            return None
        try:
            loop_value = 1 if loopback else 0
            sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, loop_value)
        except IOError as err:
            self.warning("Could not set IPv6 multicast loopback value %d: %s", loop_value, err)
            return None
        try:
            scoped_ipv6_multicast_address = (
                str(multicast_address) + '%' + self.physical_interface_name)
            sock_addr = socket.getaddrinfo(scoped_ipv6_multicast_address, port,
                                           socket.AF_INET6, socket.SOCK_DGRAM)[0][4]
            sock.connect(sock_addr)
        except (IOError, OSError) as err:
            self.warning("Could not connect UDP socket to address %s port %d: %s",
                         scoped_ipv6_multicast_address, port, err)
            return None
        return sock 

def ipv6Multicast(host='::1', maddr=maddr):
    haddr = socket.getaddrinfo(host, maddr[1], socket.AF_INET6, socket.SOCK_DGRAM)[0][-1]
    maddr = socket.getaddrinfo(maddr[0], maddr[1], socket.AF_INET6, socket.SOCK_DGRAM)[0][-1]

    sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)

    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    if hasattr(socket, "SO_REUSEPORT"):
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)

    sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 1)
    sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, 5)

    ifn = haddr[3] or if_nametoindex('lo0')
    ifn = struct.pack("I", ifn)
    sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_IF, ifn)

    group = socket.inet_pton(socket.AF_INET6, maddr[0]) + ifn
    sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, group)

    sock.bind(haddr)
    sock.setblocking(False)

    return sock, maddr

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ Main 
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

def init_v6(self):
        idx = socket.if_nametoindex(self.interface.name)
        self.multicast_address = (WSD_MCAST_GRP_V6, WSD_UDP_PORT, 0x575C, idx)

        # v6: member_request = { multicast_addr, intf_idx }
        mreq = (
            socket.inet_pton(self.family, WSD_MCAST_GRP_V6) +
            struct.pack('@I', idx))
        self.recv_socket.setsockopt(
            socket.IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, mreq)
        self.recv_socket.setsockopt(
            socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 1)

        # bind to network interface, i.e. scope and handle OS differences,
        # see Stevens: Unix Network Programming, Section 21.6, last paragraph
        try:
            self.recv_socket.bind((WSD_MCAST_GRP_V6, WSD_UDP_PORT, 0, idx))
        except OSError:
            self.recv_socket.bind(('::', 0, 0, idx))

        self.send_socket.setsockopt(
            socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 0)
        self.send_socket.setsockopt(
            socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, args.hoplimit)
        self.send_socket.setsockopt(
            socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_IF, idx)

        self.transport_address = '[{0}]'.format(self.address)
        self.listen_address = (self.address, WSD_HTTP_PORT, 0, idx) 

def set_ipv6_multicast_loopback(sock, loopback):
    """Sets IPv6 multicast loopback mode on the specified UDP socket.

    This isn't used in MAAS under normal circumstances, but it is useful for
    testing.

    :param sock: An opened IPv6 UDP socket.
    :param loopback: If True, will set up the socket to loop back transmitted
        multicast to the receive path.
    """
    sock.setsockopt(
        socket.IPPROTO_IPV6,
        socket.IPV6_MULTICAST_LOOP,
        struct.pack("I", 1 if loopback else 0),
    ) 

def new_socket(interface_number=None, interface_name=None):
    """
    Create a new socket for a given interface_number. 
    interface_name and interface_number have to be for the same interface 

    """
    #Default is IPv4
    address_family = socket.AF_INET

    intf = None #The interface used to transmit data

    if interface_number is None: 
        #No ipv6 interface given. Stay in ipv4 
        intf = socket.gethostbyname(socket.gethostname())
    else: #IPv6 
        intf = int(interface_number)
        address_family = socket.AF_INET6

    #Create socket 
    s = socket.socket(address_family, socket.SOCK_DGRAM)

    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    # SO_REUSEADDR should be equivalent to SO_REUSEPORT for
    # multicast UDP sockets (p 731, "TCP/IP Illustrated,
    # Volume 2"), but some BSD-derived systems require
    # SO_REUSEPORT to be specified explicity.  Also, not all
    # versions of Python have SO_REUSEPORT available.
    # Catch OSError and socket.error for kernel versions <3.9 because lacking
    # SO_REUSEPORT support.
    try:
        reuseport = socket.SO_REUSEPORT
    except AttributeError:
        pass
    else:
        try:
            s.setsockopt(socket.SOL_SOCKET, reuseport, 1)
        except (OSError, socket.error) as err:
            # OSError on python 3, socket.error on python 2
            if not err.errno == errno.ENOPROTOOPT:
                raise


    # OpenBSD needs the ttl and loop values for the IP_MULTICAST_TTL and
    # IP_MULTICAST_LOOP socket options as an unsigned char.
    if address_family is socket.AF_INET: 
        ttl = struct.pack(b'B', 255)
        s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
        loop = struct.pack(b'B', 1)
        s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, loop)
    
    else: #IPv6
        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, 255)
        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 1)

    if interface_name is "awdl0" and platform.system() == 'Darwin':
        s.setsockopt(socket.SOL_SOCKET, 0x1104, 1)

    #Bind the Socket
    s.bind(('', _MDNS_PORT))
    return s 

def new_socket(interface_number=None, interface_name=None):
    """
    Create a new socket for a given interface_number. 
    interface_name and interface_number have to be for the same interface 

    """
    #Default is IPv4
    address_family = socket.AF_INET

    intf = None #The interface used to transmit data

    if interface_number is None: 
        #No ipv6 interface given. Stay in ipv4 
        intf = socket.gethostbyname(socket.gethostname())
    else: #IPv6 
        intf = int(interface_number)
        address_family = socket.AF_INET6

    #Create socket 
    s = socket.socket(address_family, socket.SOCK_DGRAM)

    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    # SO_REUSEADDR should be equivalent to SO_REUSEPORT for
    # multicast UDP sockets (p 731, "TCP/IP Illustrated,
    # Volume 2"), but some BSD-derived systems require
    # SO_REUSEPORT to be specified explicity.  Also, not all
    # versions of Python have SO_REUSEPORT available.
    # Catch OSError and socket.error for kernel versions <3.9 because lacking
    # SO_REUSEPORT support.
    try:
        reuseport = socket.SO_REUSEPORT
    except AttributeError:
        pass
    else:
        try:
            s.setsockopt(socket.SOL_SOCKET, reuseport, 1)
        except (OSError, socket.error) as err:
            # OSError on python 3, socket.error on python 2
            if not err.errno == errno.ENOPROTOOPT:
                raise


    # OpenBSD needs the ttl and loop values for the IP_MULTICAST_TTL and
    # IP_MULTICAST_LOOP socket options as an unsigned char.
    if address_family is socket.AF_INET: 
        ttl = struct.pack(b'B', 255)
        s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
        loop = struct.pack(b'B', 1)
        s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, loop)
    
    else: #IPv6
        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, 255)
        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_LOOP, 1)

    if interface_name is "awdl0" and platform.system() == 'Darwin':
        s.setsockopt(socket.SOL_SOCKET, 0x1104, 1)

    #Bind the Socket
    s.bind(('', _MDNS_PORT))
    return s