NAME

IO::Socket::IP - Use IPv4 and IPv6 sockets in a protocol-independent way

SYNOPSIS

 use IO::Socket::IP;

 my $sock = IO::Socket::IP->new(
    PeerHost    => "www.google.com",
    PeerService => "www",
 ) or die "Cannot construct socket - $@";

 printf "Now connected to %s:%s\n", $sock->peerhost_service;

 ...

DESCRIPTION

This module provides a protocol-independent way to use IPv4 and IPv6 sockets. It allows new connections to be made by specifying the hostname and service name or port number. It allows for connections to be accepted by sockets listening on local ports, by service name or port number.

It uses Socket::GetAddrInfo's getaddrinfo function to convert hostname/service name pairs into sets of possible addresses to connect to. This allows it to work for IPv6 where the system supports it, while still falling back to IPv4-only on systems which don't.

It provides an API which, for most typical cases, should be a drop-in replacement for IO::Socket::INET; most constructor arguments and methods are provided in a compatible way.

CONSTRUCTOR

$sock = IO::Socket::IP->new( %args )

Creates a new IO::Socket::IP object. If any arguments are passed it will be configured to contain a newly created socket handle, and be configured according to the argmuents. The recognised arguments are:

Type => INT

The socket type (e.g. SOCK_STREAM, SOCK_DGRAM). Will be inferred by getaddrinfo from the service name if not supplied.

Proto => INT

IP protocol for the socket connection. Will be inferred by getaddrinfo from the service name, or by the kernel from the socket type, if not supplied.

PeerHost => STRING

PeerService => STRING

Hostname and service name for the peer to connect() to. The service name may be given as a port number, as a decimal string.

For symmetry with the accessor methods and compatibility with IO::Socket::INET, PeerAddr and PeerPort are accepted as synonyms respectively.

Listen => INT

Puts the socket into listening mode where new connections can be accepted using the accept method.

LocalHost => STRING

LocalService => STRING

Hostname and service name for the local address to bind() to.

For symmetry with the accessor methods and compatibility with IO::Socket::INET, LocalAddr and LocalPort are accepted as synonyms respectively.

ReuseAddr => BOOL

If true, set the SO_REUSEADDR sockopt

ReusePort => BOOL

If true, set the SO_REUSEPORT sockopt (not all OSes implement this sockopt)

Broadcast => BOOL

If true, set the SO_BROADCAST sockopt

If the constructor fails, it will set $@ to an appropriate error message; this may be from $! or it may be some other string; not every failure necessarily has an associated errno value.

If either LocalHost or PeerHost (or their ...Addr synonyms) have any of the following special forms, they are split to imply both the hostname and service name:

 hostname.example.org:port    # DNS name
 10.0.0.1:port                # IPv4 address
 [fe80::123]:port             # IPv6 address

In each case, port is passed to the LocalService or PeerService argument.

Either of LocalService or PeerService (or their ...Port synonyms) can be either a service name, a decimal number, or a string containing both a service name and number, in the form

 name(number)

In this case, the name will be tried first, but if the resolver does not understand it then the port number will be used instead.

$sock = IO::Socket::IP->new( $peeraddr )

As a special case, if the constructor is passed a single argument (as opposed to an even-sized list of key/value pairs), it is taken to be the value of the PeerAddr parameter. The example in the SYNOPSIS section may also therefore be written as

 my $sock = IO::Socket::IP->new( "www.google.com:www" )
    or die "Cannot construct socket - $@";

METHODS

( $host, $service ) = $sock->sockhost_service( $numeric )

Return the hostname and service name for the local endpoint (that is, the socket address given by the sockname method).

If $numeric is true, these will be given in numeric form rather than being resolved into names.

This method is used to implement the following for convenience wrappers. If both host and service names are required, this method is preferrable to the following wrappers, because it will call getnameinfo(3) only once.

$addr = $sock->sockhost

Return the numeric form of the local address

$port = $sock->sockport

Return the numeric form of the local port number

$host = $sock->sockhostname

Return the resolved name of the local address

$service = $sock->sockservice

Return the resolved name of the local port number

( $host, $service ) = $sock->peerhost_service( $numeric )

Similar to the sockhost_service method, but instead returns the hostname and service name for the peer endpoint (that is, the socket address given by the peername method).

$addr = $sock->peerhost

Return the numeric form of the peer address

$port = $sock->peerport

Return the numeric form of the peer port number

$host = $sock->peerhostname

Return the resolved name of the peer address

$service = $sock->peerservice

Return the resolved name of the peer port number

TODO

• Cache the returns from sockhost_service and peerhost_service to avoid double-lookup overhead in such code as

    printf "Peer is %s:%d\n", $sock->peerhost, $sock->peerport;

• Implement constructor args Timeout, Blocking and maybe Domain. Except that Domain is harder because IO::Socket wants to dispatch to subclasses based on it. Maybe Family might be a better name?

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>

cpanm IO::Socket::IP

perl -MCPAN -e shell
install IO::Socket::IP