NAME

Net::Inet - Internet socket interface module

SYNOPSIS

use Net::Gen;		# optional
use Net::Inet;

DESCRIPTION

The Net::Inet module provides basic services for handling socket-based communications for the Internet protocol family. It inherits from Net::Gen, and is a base for Net::TCP and Net::UDP.

Public Methods

new

Usage:

$obj = new Net::Inet;
$obj = new Net::Inet $desthost, $destservice;
$obj = new Net::Inet \%parameters;
$obj = new Net::Inet $desthost, $destservice, \%parameters;
$obj = 'Net::Inet'->new();
$obj = 'Net::Inet'->new($desthost, $destservice);
$obj = 'Net::Inet'->new(\%parameters);
$obj = 'Net::Inet'->new($desthost, $destservice, \%parameters);

Returns a newly-initialised object of the given class. If called for a derived class, no validation of the supplied parameters will be performed. (This is so that the derived class can set up the parameter validation it needs in the object before allowing the validation.) Otherwise, it will cause the parameters to be validated by calling its init method. In particular, this means that if both a host and a service are given, then an object will only be returned if a connect() call was successful, or if the object is non-blocking and a connect() call is in progress.

The examples above show the indirect object syntax which many prefer, as well as the guaranteed-to-be-safe static method call. There are occasional problems with the indirect object syntax, which tend to be rather obscure when encountered. See http://www.xray.mpe.mpg.de/mailing-lists/perl-porters/1998-01/msg01674.html for details.

init

Usage:

return undef unless $self->init;
return undef unless $self->init(\%parameters);
return undef unless $self->init($desthost, $destservice);
return undef unless $self->init($desthost, $destservice, \%parameters);

Verifies that all previous parameter assignments are valid (via checkparams). Returns the incoming object on success, and undef on failure. Usually called only via a derived class's init method or its own new call.

bind

Usage:

$ok = $obj->bind;
$ok = $obj->bind($lclhost, $lclservice);
$ok = $obj->bind($lclhost, $lclservice, \%parameters);

Sets up the srcaddrlist object parameter with the specified $lclhost and $lclservice arguments if supplied (via the thishost and thisport object parameters), and then returns the value from the inherited bind method. Changing of parameters is also allowed, mainly for setting debug status or timeouts.

Example:

$ok = $obj->bind(0, 'echo(7)'); # attach to the local TCP echo port

unbind

Usage:

$obj->unbind;

Deletes the thishost and thisport object parameters, and then (assuming that succeeds, which it should) returns the value from the inherited unbind method.

connect

Usage:

$ok = $obj->connect;
$ok = $obj->connect($host, $service);
$ok = $obj->connect($host, $service, \%parameters);

Attempts to establish a connection for the object. If the $host or $service arguments are specified, they will be used to set the desthost and destservice/destport object parameters, with side-effects of setting up the dstaddrlist object parameter. Then, the result of a call to the inherited connect method will be returned. Changing of parameters is also allowed, mainly for setting debug status or timeouts.

format_addr

Usage:

$string = $obj->format_addr($sockaddr);
$string = $obj->format_addr($sockaddr, $numeric_only);
$string = format_addr Module $sockaddr;
$string = format_addr Module $sockaddr, $numeric_only;

Returns a formatted representation of the address. This is a method so that it can be overridden by derived classes. It is used to implement ``pretty-printing'' methods for source and destination addresses. If the $numeric_only argument is true, the address and port number will be used even if they can be resolved to names. Otherwise, the resolved hostname and service name will be used if possible.

format_local_addr

Usage:

$string = $obj->format_local_addr;
$string = $obj->format_local_addr($numeric_only);

Returns a formatted representation of the local socket address associated with the object. A sugar-coated way of calling the format_addr method for the srcaddr object parameter.

format_remote_addr

Usage:

$string = $obj->format_remote_addr;

Returns a formatted representation of the remote socket address associated with the object. A sugar-coated way of calling the format_addr method for the dstaddr object parameter.

getsockinfo

An augmented form of Net::Gen::getsockinfo. Aside from updating more object parameters, it behaves the same as that in the base class. The additional object parameters which get set are lcladdr, lclhost, lclport, lclservice, remaddr, remhost, remport, and remservice. (They are described in "Known Object Parameters" below.)

There are also various accessor methods for the object parameters. See "Public Methods" in Net::Gen (where it talks about Accessors) for calling details. See "Known Object Parameters" below for those defined by this class.

Protected Methods

[See the note in "Protected Methods" in Net::Gen about my definition of protected methods in Perl.]

None.

Known Socket Options

These are the socket options known to the Net::Inet module itself:

IP_HDRINCL IP_RECVDSTADDR IP_RECVOPTS IP_RECVRETOPTS IP_TOS IP_TTL IP_ADD_MEMBERSHIP IP_DROP_MEMBERSHIP IP_MULTICAST_IF IP_MULTICAST_LOOP IP_MULTICAST_TTL IP_OPTIONS IP_RETOPTS

Known Object Parameters

These are the object parameters registered by the Net::Inet module itself:

IPproto

The name of the Internet protocol in use on the socket associated with the object. Set as a side-effect of setting the proto object parameter, and vice versa.

proto

Used the same way as with Net::Gen, but has a handler attached to keep it in sync with IPproto.

thishost

The source host name or address to use for the bind method. When used in conjunction with the thisservice or thisport object parameter, causes the srcaddrlist object parameter to be set, which is how it affects the bind() action. This parameter is validated, and must be either a valid internet address or a hostname for which an address can be found. If a hostname is given, and multiple addresses are found for it, then each address will be entered into the srcaddrlist array reference.

desthost

The destination host name or address to use for the connect method. When used in conjunction with the destservice or destport object parameter, causes the dstaddrlist object parameter to be set, which is how it affects the connect() action. This parameter is validated, and must be either a valid internet address or a hostname for which an address can be found. If a hostname is given, and multiple addresses are found for it, then each address will be entered into the dstaddrlist array reference, in order. This allows the connect method to attempt a connection to each address, as per RFC 1123.

thisservice

The source service name (or number) to use for the bind method. An attempt will be made to translate the supplied service name with getservbyname(). If that succeeds, or if it fails but the supplied value was strictly numeric, the port number will be set in the thisport object parameter. If the supplied value is not numeric and can't be translated, the attempt to set the value will fail. Otherwise, this causes the srcaddrlist object parameter to be updated, in preparation for an invocation of the bind method (possibly implicitly from the connect method).

thisport

The source service number (or name) to use for the bind method. An attempt will be made to translate the supplied service name with getservbyname() if it is not strictly numeric. If that succeeds, the given name will be set in the thisservice parameter, and the resolved port number will be set in the thisport object parameter. If the supplied value is strictly numeric, and a call to getservbyport can resolve a name for the service, the thisservice parameter will be updated appropriately. If the supplied value is not numeric and can't be translated, the attempt to set the value will fail. Otherwise, this causes the srcaddrlist object parameter to be updated, in preparation for an invocation of the bind method (possibly implicitly from the connect method).

destservice

The destination service name (or number) to use for the connect method. An attempt will be made to translate the supplied service name with getservbyname(). If that succeeds, or if it fails but the supplied value was strictly numeric, the port number will be set in the destport object parameter. If the supplied value is not numeric and can't be translated, the attempt to set the value will fail. Otherwise, if the desthost parameter has a defined value, this causes the dstaddrlist object parameter to be updated, in preparation for an invocation of the connect method.

destport

The destination service number (or name) to use for the connect method. An attempt will be made to translate the supplied service name with getservbyname() if it is not strictly numeric. If that succeeds, the given name will be set in the destservice parameter, and the resolved port number will be set in the destport parameter. If the supplied value is strictly numeric, and a call to getservbyport can resolve a name for the service, the destservice parameter will be updated appropriately. If the supplied value is not numeric and can't be translated, the attempt to set the value will fail. Otherwise, if the desthost parameter has a defined value, this causes the dstaddrlist object parameter to be updated, in preparation for an invocation of the connect method.

lcladdr

The local IP address stashed by the getsockinfo method after a successful bind() or connect() call.

lclhost

The local hostname stashed by the getsockinfo method after a successful bind() or connect(), as resolved from the lcladdr object parameter.

lclport

The local port number stashed by the getsockinfo method after a successful bind() or connect() call.

lclservice

The local service name stashed by the getsockinfo method after a successful bind() or connect(), as resolved from the lclport object parameter.

remaddr

The remote IP address stashed by the getsockinfo method after a successful connect() call.

remhost

The remote hostname stashed by the getsockinfo method after a successful connect() call, as resolved from the remaddr object parameter.

remport

The remote port number stashed by the getsockinfo method after a successful connect() call.

remservice

The remote service name stashed by the getsockinfo method after a successful connect() call, as resolved from the remport object parameter.

Non-Method Subroutines

inet_aton

Usage:

$in_addr = inet_aton('192.0.2.1');

Returns the packed AF_INET address in network order, if it is validly formed, or undef on error. This used to be a separate implementation in this package, but is now inherited from the Socket module.

inet_addr

A synonym for inet_aton() (for old fogeys like me who forget about the new name). (Yes, I know it's different in C, but in Perl there's no need to propagate the old inet_addr() braindamage of being unable to handle "255.255.255.255", so I didn't.)

inet_ntoa

Usage:

$addr_string = inet_ntoa($in_addr);

Returns the ASCII representation of the AF_INET address provided (if possible), or undef on error. This used to be a separate implementation in this package, but is now inherited from the Socket module.

htonl

htons

ntohl

ntohs

About as those who are used to them might expect, I think. However, these versions will return lists in list context, and will complain if given a multi-element list in scalar context.

[For those who don't know what these are, and who don't have documentation on them in their existing system documentation, these functions convert data between 'host' and 'network' byte ordering, for 'short' or 'long' network data. (This should explain the 'h', 'n', 's', and 'l' letters in the names.) Long network data means 32-bit quantities, such as IP addresses, and short network data means 16-bit quantities, such as IP port numbers. You'd only need to use these functions if you're not using the methods from this package to build your packed 'sockaddr' structures or to unpack their data after a connect() or accept().]

pack_sockaddr_in

Usage:

$connect_address = pack_sockaddr_in($family, $port, $in_addr);
$connect_address = pack_sockaddr_in($port, $in_addr);

Returns the packed struct sockaddr_in corresponding to the provided $family, $port, and $in_addr arguments. The $family and $port arguments must be numbers, and the $in_addr argument must be a packed struct in_addr such as the trailing elements from perl's gethostent() return list. This differs from the implementation in the Socket module in that the $family argument is available (though optional). The $family argument defaults to AF_INET.

unpack_sockaddr_in

Usage:

($family, $port, $in_addr) = unpack_sockaddr_in($connected_address);

Returns the address family, port, and packed struct in_addr from the supplied packed struct sockaddr_in. This is the inverse of pack_sockaddr_in(). This differs from the implementation in the Socket module in that the $family value from the socket address is returned (and might not be AF_INET).

INADDR_UNSPEC_GROUP

INADDR_ALLHOSTS_GROUP

INADDR_ALLRTRS_GROUP

INADDR_MAX_LOCAL_GROUP

Constant routines returning the unspecified local, all hosts, all routers, or the maximum possible local IP multicast group address, respectively. These routines return results in the form of a packed struct inaddr much like the INADDR_ANY result described in "INADDR_ANY" in Socket.

IN_CLASSA

IN_CLASSB

IN_CLASSC

IN_CLASSD

IN_MULTICAST

IN_EXPERIMENTAL

IN_BADCLASS

Usage:

$boolean = IN_EXPERIMENTAL(INADDR_ALLHOSTS_GROUP);
$boolean = IN_CLASSA(0x7f000001);

These routines return the network class information for the supplied IP address. Of these, only IN_BADCLASS() and IN_MULTICAST() are really useful in today's Internet, since the advent of CIDR (classless Internet domain routing). In particular, IN_EXPERIMENTAL() is at the mercy of your vendor's definition. The first example above will be true only on older systems, which almost certainly don't support IP multicast anyway. The argument to any of these functions can be either a packed struct inaddr such as that returned by inet_ntoa() or unpack_sockaddr_in(), or an integer (or integer expression) giving an IP address in host byte order.

IPOPT_CLASS

IPOPT_COPIED

IPOPT_NUMBER

Usage:

$optnum = IPOPT_NUMBER($option);

These routines extract information from IP option numbers, as per the information on IP options in RFC 791.

...

Other constants which relate to parts of IP or ICMP headers or vendor-defined socket options, as listed in "Exports" below.

Exports

default

INADDR_ALLHOSTS_GROUP INADDR_ALLRTRS_GROUP INADDR_ANY INADDR_BROADCAST INADDR_LOOPBACK INADDR_MAX_LOCAL_GROUP INADDR_NONE INADDR_UNSPEC_GROUP IPPORT_RESERVED IPPORT_USERRESERVED IPPORT_DYNAMIC IPPROTO_EGP IPPROTO_EON IPPROTO_GGP IPPROTO_HELLO IPPROTO_ICMP IPPROTO_IDP IPPROTO_IGMP IPPROTO_IP IPPROTO_IPIP IPPROTO_MAX IPPROTO_PUP IPPROTO_RAW IPPROTO_RSVP IPPROTO_TCP IPPROTO_TP IPPROTO_UDP htonl htons inet_addr inet_aton inet_ntoa ntohl ntohs

exportable

DEFTTL ICMP_ADVLENMIN ICMP_ECHO ICMP_ECHOREPLY ICMP_INFOTYPE ICMP_IREQ ICMP_IREQREPLY ICMP_MASKLEN ICMP_MASKREPLY ICMP_MASKREQ ICMP_MAXTYPE ICMP_MINLEN ICMP_PARAMPROB ICMP_REDIRECT ICMP_REDIRECT_HOST ICMP_REDIRECT_NET ICMP_REDIRECT_TOSHOST ICMP_REDIRECT_TOSNET ICMP_SOURCEQUENCH ICMP_TIMXCEED ICMP_TIMXCEED_INTRANS ICMP_TIMXCEED_REASS ICMP_TSLEN ICMP_TSTAMP ICMP_TSTAMPREPLY ICMP_UNREACH ICMP_UNREACH_HOST ICMP_UNREACH_NEEDFRAG ICMP_UNREACH_NET ICMP_UNREACH_PORT ICMP_UNREACH_PROTOCOL ICMP_UNREACH_SRCFAIL IN_BADCLASS IN_CLASSA IN_CLASSA_HOST IN_CLASSA_MAX IN_CLASSA_NET IN_CLASSA_NSHIFT IN_CLASSA_SUBHOST IN_CLASSA_SUBNET IN_CLASSA_SUBNSHIFT IN_CLASSB IN_CLASSB_HOST IN_CLASSB_MAX IN_CLASSB_NET IN_CLASSB_NSHIFT IN_CLASSB_SUBHOST IN_CLASSB_SUBNET IN_CLASSB_SUBNSHIFT IN_CLASSC IN_CLASSC_HOST IN_CLASSC_MAX IN_CLASSC_NET IN_CLASSC_NSHIFT IN_CLASSD IN_CLASSD_HOST IN_CLASSD_NET IN_CLASSD_NSHIFT IN_EXPERIMENTAL IN_LOOPBACKNET IN_MULTICAST IPFRAGTTL IPOPT_CIPSO IPOPT_CLASS IPOPT_CONTROL IPOPT_COPIED IPOPT_DEBMEAS IPOPT_EOL IPOPT_LSRR IPOPT_MINOFF IPOPT_NOP IPOPT_NUMBER IPOPT_OFFSET IPOPT_OLEN IPOPT_OPTVAL IPOPT_RESERVED1 IPOPT_RESERVED2 IPOPT_RIPSO_AUX IPOPT_RR IPOPT_SATID IPOPT_SECURITY IPOPT_SECUR_CONFID IPOPT_SECUR_EFTO IPOPT_SECUR_MMMM IPOPT_SECUR_RESTR IPOPT_SECUR_SECRET IPOPT_SECUR_TOPSECRET IPOPT_SECUR_UNCLASS IPOPT_SSRR IPOPT_TS IPOPT_TS_PRESPEC IPOPT_TS_TSANDADDR IPOPT_TS_TSONLY IPPORT_TIMESERVER IPTOS_LOWDELAY IPTOS_PREC_CRITIC_ECP IPTOS_PREC_FLASH IPTOS_PREC_FLASHOVERRIDE IPTOS_PREC_IMMEDIATE IPTOS_PREC_INTERNETCONTROL IPTOS_PREC_NETCONTROL IPTOS_PREC_PRIORITY IPTOS_PREC_ROUTINE IPTOS_RELIABILITY IPTOS_THROUGHPUT IPTTLDEC IPVERSION IP_ADD_MEMBERSHIP IP_DEFAULT_MULTICAST_LOOP IP_DEFAULT_MULTICAST_TTL IP_DF IP_DROP_MEMBERSHIP IP_HDRINCL IP_MAXPACKET IP_MAX_MEMBERSHIPS IP_MF IP_MSS IP_MULTICAST_IF IP_MULTICAST_LOOP IP_MULTICAST_TTL IP_OPTIONS IP_RECVDSTADDR IP_RECVOPTS IP_RECVRETOPTS IP_RETOPTS IP_TOS IP_TTL MAXTTL MAX_IPOPTLEN MINTTL SUBNETSHIFT pack_sockaddr_in unpack_sockaddr_in

tags

The following :tags are in %EXPORT_TAGS, with the associated exportable values as listed:

:sockopts

IP_HDRINCL IP_RECVDSTADDR IP_RECVOPTS IP_RECVRETOPTS IP_TOS IP_TTL IP_ADD_MEMBERSHIP IP_DROP_MEMBERSHIP IP_MULTICAST_IF IP_MULTICAST_LOOP IP_MULTICAST_TTL IP_OPTIONS IP_RETOPTS

:routines

pack_sockaddr_in unpack_sockaddr_in inet_ntoa inet_aton inet_addr htonl ntohl htons ntohs ICMP_INFOTYPE IN_BADCLASS IN_EXPERIMENTAL IN_MULTICAST IPOPT_CLASS IPOPT_COPIED IPOPT_NUMBER

:icmpvalues

ICMP_ADVLENMIN ICMP_ECHO ICMP_ECHOREPLY ICMP_IREQ ICMP_IREQREPLY ICMP_MASKLEN ICMP_MASKREPLY ICMP_MASKREQ ICMP_MAXTYPE ICMP_MINLEN ICMP_PARAMPROB ICMP_REDIRECT ICMP_REDIRECT_HOST ICMP_REDIRECT_NET ICMP_REDIRECT_TOSHOST ICMP_REDIRECT_TOSNET ICMP_SOURCEQUENCH ICMP_TIMXCEED ICMP_TIMXCEED_INTRANS ICMP_TIMXCEED_REASS ICMP_TSLEN ICMP_TSTAMP ICMP_TSTAMPREPLY ICMP_UNREACH ICMP_UNREACH_HOST ICMP_UNREACH_NEEDFRAG ICMP_UNREACH_NET ICMP_UNREACH_PORT ICMP_UNREACH_PROTOCOL ICMP_UNREACH_SRCFAIL

:ipoptions

IPOPT_CIPSO IPOPT_CONTROL IPOPT_DEBMEAS IPOPT_EOL IPOPT_LSRR IPOPT_MINOFF IPOPT_NOP IPOPT_OFFSET IPOPT_OLEN IPOPT_OPTVAL IPOPT_RESERVED1 IPOPT_RESERVED2 IPOPT_RIPSO_AUX IPOPT_RR IPOPT_SATID IPOPT_SECURITY IPOPT_SECUR_CONFID IPOPT_SECUR_EFTO IPOPT_SECUR_MMMM IPOPT_SECUR_RESTR IPOPT_SECUR_SECRET IPOPT_SECUR_TOPSECRET IPOPT_SECUR_UNCLASS IPOPT_SSRR IPOPT_TS IPOPT_TS_PRESPEC IPOPT_TS_TSANDADDR IPOPT_TS_TSONLY MAX_IPOPTLEN

:iptosvalues

IPTOS_LOWDELAY IPTOS_PREC_CRITIC_ECP IPTOS_PREC_FLASH IPTOS_PREC_FLASHOVERRIDE IPTOS_PREC_IMMEDIATE IPTOS_PREC_INTERNETCONTROL IPTOS_PREC_NETCONTROL IPTOS_PREC_PRIORITY IPTOS_PREC_ROUTINE IPTOS_RELIABILITY IPTOS_THROUGHPUT

:protocolvalues

DEFTTL INADDR_ALLHOSTS_GROUP INADDR_ALLRTRS_GROUP INADDR_ANY INADDR_BROADCAST INADDR_LOOPBACK INADDR_MAX_LOCAL_GROUP INADDR_NONE INADDR_UNSPEC_GROUP IN_LOOPBACKNET IPPORT_RESERVED IPPORT_USERRESERVED IPPORT_DYNAMIC IPPROTO_EGP IPPROTO_EON IPPROTO_GGP IPPROTO_HELLO IPPROTO_ICMP IPPROTO_IDP IPPROTO_IGMP IPPROTO_IP IPPROTO_IPIP IPPROTO_MAX IPPROTO_PUP IPPROTO_RAW IPPROTO_RSVP IPPROTO_TCP IPPROTO_TP IPPROTO_UDP IPFRAGTTL IPTTLDEC IPVERSION IP_DF IP_MAXPACKET IP_MF IP_MSS MAXTTL MAX_IPOPTLEN MINTTL

:ipmulticast

IP_ADD_MEMBERSHIP IP_DEFAULT_MULTICAST_LOOP IP_DEFAULT_MULTICAST_TTL IP_DROP_MEMBERSHIP IP_MAX_MEMBERSHIPS IP_MULTICAST_IF IP_MULTICAST_LOOP IP_MULTICAST_TTL

:deprecated

IN_CLASSA_HOST IN_CLASSA_MAX IN_CLASSA_NET IN_CLASSA_NSHIFT IN_CLASSA_SUBHOST IN_CLASSA_SUBNET IN_CLASSA_SUBNSHIFT IN_CLASSB_HOST IN_CLASSB_MAX IN_CLASSB_NET IN_CLASSB_NSHIFT IN_CLASSB_SUBHOST IN_CLASSB_SUBNET IN_CLASSB_SUBNSHIFT IN_CLASSC_HOST IN_CLASSC_MAX IN_CLASSC_NET IN_CLASSC_NSHIFT IN_CLASSD_HOST IN_CLASSD_NET IN_CLASSD_NSHIFT IN_CLASSA IN_CLASSB IN_CLASSC IN_CLASSD IPPORT_TIMESERVER SUBNETSHIFT

:ALL

All of the above exportable items.

NOTES

Anywhere a service or port argument is used above, the allowed syntax is either a service name, a port number, or a service name with a caller-supplied default port number. Examples are 'echo', 7, and 'echo(7)', respectively. For a service argument, a bare port number must be translatable into a service name with getservbyport() or an error will result. A service name must be translatable into a port with getservbyname() or an error will result. However, a service name with a default port number will succeed (by using the supplied default) even if the translation with getservbyname() fails.

For example:

$obj->setparam('destservice', 'http(80)');

This always succeeds, although if your /etc/services file (or equivalent for non-UNIX systems) maps "http" to something other than port 80, you'll get that other port.

For a contrasting example:

$obj->setparam('destservice', 80);

This will fail, despite the numeric value, if your /etc/services file (or equivalent) is behind the times and has no mapping to a service name for port 80.

THREADING STATUS

This module has been tested with threaded perls, and should be as thread-safe as perl itself. (As of 5.005_03 and 5.005_57, that's not all that safe just yet.) It also works with interpreter-based threads ('ithreads') in more recent perl releases.

SEE ALSO

Net::Gen(3), Net::TCP(3), Net::UDP(3)

AUTHOR

Spider Boardman <spidb@cpan.org>