Socket

# NAME

Socket, sockaddr_in, sockaddr_un, inet_aton, inet_ntoa - load the C socket.h defines and structure manipulators

# SYNOPSIS

        use Socket;
        $proto = getprotobyname('udp');
        socket(Socket_Handle, PF_INET, SOCK_DGRAM, $proto);
        $iaddr = gethostbyname('hishost.com');
        $port = getservbyname('time', 'udp');
        $sin = sockaddr_in($port, $iaddr);
        send(Socket_Handle, 0, 0, $sin);
        $proto = getprotobyname('tcp');
        socket(Socket_Handle, PF_INET, SOCK_STREAM, $proto);
        $port = getservbyname('smtp');
        $sin = sockaddr_in($port,inet_aton("127.1"));
        $sin = sockaddr_in(7,inet_aton("localhost"));
        $sin = sockaddr_in(7,INADDR_LOOPBACK);
        connect(Socket_Handle,$sin);
        ($port, $iaddr) = sockaddr_in(getpeername(Socket_Handle));
        $peer_host = gethostbyaddr($iaddr, AF_INET);
        $peer_addr = inet_ntoa($iaddr);
        $proto = getprotobyname('tcp');
        socket(Socket_Handle, PF_UNIX, SOCK_STREAM, $proto);
        unlink('/tmp/usock');
        $sun = sockaddr_un('/tmp/usock');
        connect(Socket_Handle,$sun);

# DESCRIPTION

This module is just a translation of the C socket.h file. Unlike the old mechanism of requiring a translated socket.ph file, this uses the h2xs program (see the Perl source distribution) and your native C compiler. This means that it has a far more likely chance of getting the numbers right. This includes all of the commonly used pound-defines like AF_INET, SOCK_STREAM, etc.

In addition, some structure manipulation functions are available:

inet_aton HOSTNAME
  Takes a string giving the name of a host, and translates that to the 4-byte string (structure). Takes arguments of both the 'rtfm.mit.edu' type and '18.181.0.24'. If the host name cannot be resolved, returns undef.

inet_ntoa IP_ADDRESS
  Takes a four byte ip address (as returned by inet_aton() ) and translates it into a string of the form 'd.d.d.d' where the 'd's are numbers less than 256 (the normal readable four dotted number notation for internet addresses).

INADDR_ANY
  Note: does not return a number, but a packed string.

  Returns the 4-byte wildcard ip address which specifies any of the hosts ip addresses. (A particular machine can have more than one ip address, each address corresponding to a particular network interface. This wildcard address allows you to bind to all of them simultaneously.) Normally equivalent to inet_aton('0.0.0.0').

INADDR_LOOPBACK
  Note - does not return a number.

  Returns the 4-byte loopback address. Normally equivalent to inet_aton('localhost').

INADDR_NONE
  Note - does not return a number.

  Returns the 4-byte invalid ip address. Normally equivalent to inet_aton('255.255.255.255').

sockaddr_in PORT, ADDRESS

sockaddr_in SOCKADDR_IN
  In an array context, unpacks its SOCKADDR_IN argument and returns an array consisting of (PORT, ADDRESS). In a scalar context, packs its (PORT, ADDRESS) arguments as a SOCKADDR_IN and returns it. If this is confusing, use pack_sockaddr_in() and unpack_sockaddr_in() explicitly.

pack_sockaddr_in PORT, IP_ADDRESS
  Takes two arguments, a port number and a 4 byte IP_ADDRESS (as returned by inet_aton() ). Returns the sockaddr_in structure with those arguments packed in with AF_INET filled in. For internet domain sockets, this structure is normally what you need for the arguments in bind() , connect() , and send() , and is also returned by getpeername() , getsockname() and recv() .

unpack_sockaddr_in SOCKADDR_IN
  Takes a sockaddr_in structure (as returned by pack_sockaddr_in() ) and returns an array of two elements: the port and the 4-byte ip-address. Will croak if the structure does not have AF_INET in the right place.

sockaddr_un PATHNAME

sockaddr_un SOCKADDR_UN
  In an array context, unpacks its SOCKADDR_UN argument and returns an array consisting of (PATHNAME). In a scalar context, packs its PATHANE arguments as a SOCKADDR_UN and returns it. If this is confusing, use pack_sockaddr_un() and unpack_sockaddr_un() explicitly. These are only supported if your system has <sys/un.h>.

pack_sockaddr_un PATH
  Takes one argument, a pathname. Returns the sockaddr_un structure with that path packed in with AF_UNIX filled in. For unix domain sockets, this structure is normally what you need for the arguments in bind() , connect() , and send() , and is also returned by getpeername() , getsockname() and recv() .

unpack_sockaddr_un SOCKADDR_UN
  Takes a sockaddr_un structure (as returned by pack_sockaddr_un() ) and returns the pathname. Will croak if the structure does not have AF_UNIX in the right place.