Net::Gen - generic sockets interface handling
use Net::Gen;
The Net::Gen module provides basic services for handling socket-based communications. It supports no particular protocol family directly, however, so it is of direct use primarily to implementors of other modules. To this end, several housekeeping functions are provided for the use of derived classes, as well as several inheritable methods. The Net::Gen class does inherit from IO::Handle, thus making its methods available. See IO::Handle::METHODS for details on those methods. However, some of those methods are overridden, so be sure to check the methods described below to be sure. (In particular, the fcntl and ioctl methods are overridden.)
Net::Gen
IO::Handle
IO::Handle::METHODS
fcntl
ioctl
Also provided in this distribution are Net::Inet, Net::TCP, Net::TCP::Server, Net::UDP, Net::UNIX, and Net::UNIX::Server, which are layered atop Net::Gen.
Net::Inet
Net::TCP
Net::TCP::Server
Net::UDP
Net::UNIX
Net::UNIX::Server
The public methods are listed alphabetically below. Here is an indication of their functional groupings:
new, new_from_fd, new_from_fh, init, checkparams, open, connect, bind, listen
new
new_from_fd
new_from_fh
init
checkparams
open
connect
bind
listen
setparams, setparam, delparams, delparam, getparams, getparam, param_saver
setparams
setparam
delparams
delparam
getparams
getparam
param_saver
unbind, condition, getsopt, getropt, setsopt, setropt, fcntl, ioctl
unbind
condition
getsopt
getropt
setsopt
setropt
getsockinfo, shutdown, stopio, close
getsockinfo
shutdown
stopio
close
isopen, isconnected, isbound, didlisten, fhvec, getfh, fileno
isopen
isconnected
isbound
didlisten
fhvec
getfh
fileno
send, sendto, put, recv, get, getline, gets, select, accept
send
sendto
put
recv
get
getline
gets
select
accept
format_addr, format_local_addr, format_remote_addr
format_addr
format_local_addr
format_remote_addr
SEND, PRINT, PRINTF, RECV, READLINE, READ, GETC, WRITE, CLOSE, EOF, BINMODE, FILENO, TIEHANDLE
SEND
PRINT
PRINTF
RECV
READLINE
READ
GETC
WRITE
CLOSE
EOF
BINMODE
FILENO
TIEHANDLE
FETCH, STORE, TIESCALAR
FETCH
STORE
TIESCALAR
Any of the keys known to the getparam and setparams methods may be used as an accessor function. See "Known Object Parameters" below, and the related sections in the derived classes. For an example, see blocking, below.
blocking
The descriptions, listed alphabetically:
Usage:
$newobj = $obj->accept;
Returns a new object in the same class as the given object if an accept() call succeeds, and undef otherwise. If the accept() call succeeds, the new object is marked as being open, connected, and bound. This can fail unexpectedly if the listening socket is non-blocking or if the object has a timeout parameter. See the discussion of non-blocking sockets and timeouts in "connect" below.
undef
timeout
$ok = $obj->bind;
Makes a call to the bind() builtin on the filehandle associated with the object. The arguments to bind() are determined from the current parameters of the object. First, if the filehandle has previously been bound or connected, it is closed. Then, if it is not currently open, a call to the open method is made. If all that works (which may be a no-op), then the following list of possible values is tried for the bind() builtin: First, the srcaddrlist object parameter, if its value is an array reference. The elements of the array are tried in order until a bind() succeeds or the list is exhausted. Second, if the srcaddrlist parameter is not set to an array reference, if the srcaddr parameter is a non-null string, it will be used. Finally, if neither srcaddrlist nor srcaddr is suitably set, the AF parameter will be used to construct a sockaddr structure which will be mostly zeroed, and the bind() will be attempted with that. If the bind() fails, undef will be returned at this point. Otherwise, a call to the getsockinfo method will be made, and then the value from a call to the isbound method will be returned.
srcaddrlist
srcaddr
AF
sockaddr
If all that seems too confusing, don't worry. Most clients will never need to do an explicit bind call, anyway. If you're writing a server or a privileged client which does need to bind to a particular local port or address, and you didn't understand the foregoing discussion, you may be in trouble. Don't panic until you've checked the discussion of binding in the derived class you're using, however.
binmode(TIEDFH);
A no-op provided for the tied file handle support of perl 5.005_57. The sockets managed by this module are always set binmode() anyway.
$isblocking = $obj->blocking; $oldblocking = $obj->blocking($newvalue);
The blocking method is an example of an accessor method. The above usage examples are (effectively) equivalent to the following code snippets, respectively:
$isblocking = $obj->getparam('blocking'); $oldblocking = $obj->getparam('blocking'); $obj->setparams({blocking=>$newvalue});
The getparam method call is skipped if the accessor method was called in void context.
$ok = $obj->checkparams;
Verifies that all previous parameter assignments are valid. (Normally called only via the init method, rather than directly.)
$ok = $obj->close; $ok = close(TIEDFH);
The close method is like a call to the shutdown method followed by a call to the stopio method. It is the standard way to close down an object.
$obj->condition;
(Re-)establishes the condition of the associated filehandle after an open() or accept(). (In other words, the open and accept methods call the condition method.) Sets the socket to be autoflushed and marks it binmode(). This method attempts to set the socket blocking or non-blocking, depending on the state of the object's blocking parameter. (It may update that parameter if the socket's state cannot be made to match.) No useful value is returned.
$ok = $obj->connect;
Attempts to establish a connection for the object. [Note the special information for re-trying connects on non-blocking sockets, later in this section.]
First, if the object is currently connected or has been connected since the last time it was opened, its close method is called. Then, if the object is not currently open, its open method is called. If it's not open after that, undef is returned. If it is open, and if either of its srcaddrlist or srcaddr parameters are set to indicate that a bind() is desired, and it is not currently bound, its bind method is called. If the bind method is called and fails, undef is returned. (Most of the foregoing is a no-op for simple clients, so don't panic.)
Next, if the dstaddrlist object parameter is set to an array reference, a call to connect() is made for each element of the list until it succeeds or the list is exhausted. If the dstaddrlist parameter is not an array reference, a single attempt is made to call connect() with the dstaddr object parameter. If no connect() call succeeded, undef is returned. Finally, a call is made to the object's getsockinfo method, and then the value from a call to its isconnected method is returned.
dstaddrlist
dstaddr
Each of the attempts with the connect() builtin is timed out separately. If there is no timeout parameter for the object, and the socket is blocking (which is the default), the timeout period is strictly at the mercy of your operating system. If there is no timeout parameter and the socket is non-blocking, that's effectively the same as having a timeout parameter value of 0. If there is a timeout parameter, the socket is made non-blocking temporarily (see "param_saver" below), and the indicated timeout value will be used to limit the connection attempt. An attempt is made to preserve any meaningful $! values when all connection attempts have failed. In particular, if the timeout parameter is 0, then each failed connect returns without completing the processing of the dstaddrlist object parameter. This is so that the re-try logic for connections in progress will be more useful.
0
If, on entry to the connect method, the object is already marked as having a connection in progress ($obj->isconnecting returns true), then the connection will be re-tried with a timeout of 0 to see whether it has succeeded in the meanwhile. The appropriate success/fail condition for that check will be returned, with no further processing of the dstaddrlist object parameter.
$obj->isconnecting
Note that the derived classes tend to provide additional capabilities which make the connect method easier to use than the above description would indicate.
$ok = $obj->delparam($keyname);
Sugar-coated call to the delparams method.
$ok = $obj->delparams(\@keynames);
Removes the settings for the specified parameters. Uses the setparams method (with undef for the values) to validate that the removal is allowed by the owning object. If the invocation of setparams is successful, then the parameters in question are removed. Returns 1 if all the removals were successful, and undef otherwise.
$ok = $obj->didlisten;
Returns true if the object's listen method has been used successfully, and the object is still bound. If this method has not been overridden by a derived class, the value is undef on failure and the $maxqueue value used for the listen() builtin on success.
$maxqueue
$iseof = $obj->EOF(); $iseof = eof(TIEDFH);
Provided for tied filehandle support. Determines whether select() says that a read would work immediately, and tries it if so. If the read was tried and returned an eof condition, 1 is returned. The return is 0 on read errors or when select() said that a read would block. Note that this interferes with use of the select() built-in, since it has to buffer the read data if the read was successful.
$rval = $obj->fcntl($func, $value);
Returns the result of an fcntl() call on the associated I/O stream.
$data = $TIED_SCALAR;
This is for the support of the TIESCALAR interface. It returns the result of a call to the READLINE method on the underlying object.
$vecstring = $obj->fhvec;
Returns a vector suitable as an argument to the 4-argument select() call. This is for use in doing selects with multiple I/O streams. See also "select".
$fnum = $obj->fileno; $fnum = fileno(TIEDFH);
Returns the actual file descriptor number for the underlying socket. See "getfh" for some restrictions as to the safety of using this.
$string = $obj->format_addr($sockaddr); $string = format_addr Module $sockaddr;
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.
$string = $obj->format_local_addr;
Returns a formatted representation of the local socket address associated with the object.
$string = $obj->format_remote_addr;
Returns a formatted representation of the remote socket address associated with the object.
This is just a sugar-coated way to call the recv method which will work with indirect-object syntax. See "recv" for details.
$char = $obj->GETC; $char = getc(TIEDFH);
This method uses the recv method with a $flags argument of 0 and a $maxlen argument of 1 to emulate the getc() builtin. Like that builtin, it returns a string representing the character read when successful, and undef on eof or errors. This method exists for the support of tied filehandles. It's unreliable for non-blocking sockets.
$fhandle = $obj->getfh;
I've strongly resisted giving people direct access to the filehandle embedded in the object because of the problems of mixing stdio input calls and traditional socket-level I/O. However, if you're sure you can keep things straight, here are the rules under which it's safe to use the embedded filehandle:
stdio
Don't use perl's own stdio calls. Stick to sysread() and recv().
Don't use the object's getline method, since that stores a read-ahead buffer in the object which only the object's own get/recv and getline methods know to return to you. (The object's select method knows about the buffer enough to tell you that a read will succeed if there's saved data, though.) Similarly, avoid the object's EOF method.
Please don't change the state of the socket behind my back. That means no close(), shutdown(), connect(), bind(), or listen() built-ins. Use the corresponding methods instead, or all bets are off. Of course, if you're only using this module to get the connect() or bind() processing, and you're going to discard the object after you've done your I/O, then it's OK to use the built-ins for I/O. Just don't expect my code to know what you did behind my back.
That $fh is a glob ref, by the way, but that doesn't matter for calling the built-in I/O primitives.
$fh
$line = $obj->getline;
This is a simulation of scalar(<$filehandle>) that doesn't let stdio confuse the get/recv method. As such, its return value is not necessarily a complete line when the socket is non-blocking.
scalar(<$filehandle>)
@lines = $obj->getlines;
This is a lot like @lines = <$filehandle>, except that it doesn't let stdio confuse the get/recv method. It's unreliable on non-blocking sockets. It will produce a fatal (but trappable) error if not called in list context. (In other words, it uses the die() builtin when not called in list context.)
@lines = <$filehandle>
$value = $obj->getparam($key, $defval, $def_if_undef); $value = $obj->getparam($key, $defval); $value = $obj->getparam($key);
Returns the current setting for the named parameter (in the current object), or the specified default value if the parameter is not in the object's current parameter list. If the optional $def_if_undef parameter is true, then undefined values will be treated the same as non-existent keys, and thus will return the supplied default value ($defval).
$def_if_undef
$defval
%hash = $obj->getparams(\@keynames, $noundefs); %hash = $obj->getparams(\@keynames); $llen = $obj->getparams(\@keynames, $noundefs); $llen = $obj->getparams(\@keynames);
Returns a hash as a list (not a reference) consisting of the key-value pairs corresponding to the specified keyname list. Only those keys which exist in the current parameter list of the object will be returned. If the $noundefs parameter is present and true, then existing keys with undefined values will be suppressed as with non-existent keys. If called in scalar context, returns the number of values which would have been returned in list context. (This is twice the number of key-value pairs, in case that wasn't clear.)
$noundefs
$optsetting = $obj->getropt($level, $option); $optsetting = $obj->getropt($optname);
Returns the raw value from a call to the getsockopt() builtin. If both the $level and $option arguments are given as numbers, the getsockopt() call will be made even if the given socket option is not registered with the object. Otherwise, the return value for unregistered options will be undef with the value of $! set as described below for the getsopt method.
$level
$option
$line = $obj->gets;
This is a simulation of scalar(<$filehandle>) that doesn't let stdio confuse the get/recv method. (The gets method is just an alias for the getline method, for partial compatibility with the POSIX module.) This method is deprecated. Use the getline method by that name, instead. The gets method may disappear in a future release.
($localsockaddr, $peersockaddr) = $obj->getsockinfo; $peersockaddr = $obj->getsockinfo;
Attempts to determine connection parameters associated with the object. If a getsockname() call on the associated filehandle succeeds, the srcaddr object parameter is set to that returned sockaddr. If a getpeername() call on the associated filehandle succeeds, the dstaddr parameter is set to that returned sockaddr. In scalar context, if both socket addresses were found, the getpeername() value is returned, otherwise undef is returned. In list context, the getsockname() and getpeername() values are returned, unless both are undefined.
Derived classes normally override this method with one which provides friendlier return information appropriate to the derived class, and which establishes more of the object parameters.
@optvals = $obj->getsopt($level, $option); @optvals = $obj->getsopt($optname);
Returns the unpacked values from a call to the getsockopt() builtin. In order to do the unpacking, the socket option must have been registered with the object. See the additional discussion of socket options in "initsockopts" below.
Since registered socket options are known by name as well as by their level and option values, it is possible to make calls using only the option name. If the name is not registered with the object, the return value is the same as that for getsopt $obj -1,-1, which is an empty return array and $! set appropriately (should be EINVAL).
getsopt $obj -1,-1
EINVAL
Examples:
($sotype) = $obj->getsopt('SO_TYPE'); @malinger = $obj->getsopt(SOL_SOCKET, SO_LINGER); ($sodebug) = $obj->getsopt('SOL_SOCKET', 'SO_DEBUG');
return undef unless $self->init;
Verifies that all previous parameter assignments are valid (via checkparams). Returns the incoming object on success, and undef on failure. This method is normally called from the new method appropriate to the class of the created object.
$rval = $obj->ioctl($func, $value);
Returns the result of an ioctl() call on the associated I/O stream.
$ok = $obj->isbound;
Returns true if the object's bind method has been used successfully, and the binding is still in effect. If this method has not been overridden by a derived class, the value is the saved return value of the call to the bind() builtin (if it was called).
$ok = $obj->isconnected;
Returns true if the object's connect method has been used successfully to establish a "session", and that session is still connected. If this method has not been overridden by a derived class, the value is the saved return value of the call to the connect() builtin (if it was called).
$ok = $obj->isconnecting;
Returns true if the object's connect method has been used with a timeout or on a non-blocking socket, and the connect() did not complete. In other words, the failure from the connect() builtin indicated that the operation was still in progress. (A rejected connection or a connection which exceeded the operating system's timeout is said to have completed unsuccessfully, rather than not to have completed.)
$ok = $obj->isopen;
Returns true if the object currently has a socket attached to its associated filehandle, and false otherwise. If this method has not been overridden by a derived class, the value is the saved return value of the call to the socket() builtin (if it was called).
$ok = $obj->listen($maxqueue); $ok = $obj->listen;
Makes a call to the listen() builtin on the filehandle associated with the object. Propagates the return value from listen(). If the $maxqueue parameter is missing, it defaults to the value of the object's maxqueue parameter, or the value of SOMAXCONN. If the SOMAXCONN constant is not available in your configuration, the default value used for the listen method is 5. This method will fail if the object is not bound and cannot be made bound by a simple call to its bind method.
SOMAXCONN
$obj = $classname->new(); $obj = $classname->new(\%parameters);
Returns a newly-initialised object of the given class. If called for a class other than Net::Gen, no validation of the supplied parameters will be performed. (This is so that the derived class can add the parameter validation it needs to the object before allowing validation.)
$obj = $classname->new_from_fh(*FH); $obj = $classname->new_from_fh(\*FH); $obj = $classname->new_from_fd(fileno($fh));
Returns a newly-initialised object of the given class, open on a newly-dup()ed copy of the given filehandle or file descriptor. As many of the standard object parameters as possible will be determined from the passed filehandle. This is determined (in part) by calling the corresponding new, init, and getsockinfo methods for the new object.
Only real filehandles or file descriptor numbers are allowed as arguments. This method makes no attempt to resolve filehandle names. Yes, despite having two names, there's really just one method.
$ok = $obj->open;
Makes a call to the socket() builtin, using the current object parameters to determine the desired protocol family, socket type, and protocol number. If the object was already open, its stopio method will be called before socket() is called again. The object parameters consulted (and possibly updated) are PF, AF, proto, type, and blocking. Returns true if the socket() call results in an open filehandle, undef otherwise.
PF
proto
type
my $savedstuff = $obj->param_saver(@param_names); my $savedstuff = $obj->paramSaver(@param_names);
Saves the values (or lack thereof) for the indicated parameter names by wrapping them (and the original object) in an object blessed into an alternate package. When this `saver' object is destroyed (typically because the `my' variable went out of scope), the previous values of the parameters for the original object will be restored. This allows for temporary changes to an object's parameter settings without the worry of whether an inopportune die() will prevent the restoration of the original settings.
An example (from the connect method):
my $saveblocking = $self->param_saver('blocking');
(This is used when there is a timeout parameter for the object.)
See "put" for details, as this method is just an alias for the put method. The PRINT alias is for the support of tied filehandles.
$ok = $obj->PRINTF($format, @args); $ok = printf TIEDFH $format, @args;
This method uses the sprintf() builtin and the PRINT method to send the @args values to the filehandle associated with the object, using the $format format string. It exists for the support of tied filehandles.
$ok = $obj->put(@whatever); $ok = put $obj @whatever;
This method uses the print() builtin to send the @whatever arguments to the filehandle associated with the object. That filehandle is always marked for autoflushing by the open method, so the method is in effect equivalent to this:
$ok = $obj->send(join($, , @whatever) . $\ , 0);
However, since multiple fwrite() calls are sometimes involved in the actual use of print(), this method can be more efficient than the above code sample for large strings in the argument list. It's a bad idea except on stream sockets (SOCK_STREAM) though, since the record boundaries are unpredictable through stdio. It's also a bad idea on non-blocking sockets, since the amount of data actually written to the socket is unknown. This method makes no attempt to trap SIGPIPE.
SOCK_STREAM
SIGPIPE
$numread = $obj->READ($buffer, $maxlen); $numread = $obj->READ($buffer, $maxlen, $offset); $numread = read(TIEDFH, $buffer, $maxlen); $numread = read(TIEDFH, $buffer, $maxlen, $offset);
This method uses the recv method (with a flags argument of 0) to emulate the read() and sysread() builtins. This is specifically for the support of tied filehandles. Like the emulated builtins, this method returns the number of bytes successfully read, or undef on error.
$line = $obj->READLINE; @lines = $obj->READLINE; $line = readline(TIEDFH); # or $line = <TIEDFH>; @lines = readline(TIEDFH); # or @lines = <TIEDFH>;
This method supports the use of the <> (or readline()) operator on tied filehandles. In scalar context, it uses the getline method. In list context, it reads all remaining input on the socket (until eof, which makes this unsuitable for connectionless socket types such as UDP), and splits it into lines based on the current value of the $/ variable. The return value is unreliable for non-blocking sockets.
$from = $obj->RECV($buffer, $maxlen, $flags); $from = $obj->RECV($buffer, $maxlen); $from = $obj->RECV($buffer);
This method calls the recv() method with the arguments and return rearranged to match the recv() builtin. This is for the support of tied filehandles.
$record = $obj->recv($maxlen, $flags, $whence); $record = $obj->recv($maxlen, $flags); $record = $obj->recv($maxlen); $record = $obj->recv;
This method calls the recv() builtin, and returns a buffer (if one is received) or undef on eof or error. If an eof is seen on the socket (as checked with its ckeof method), then $! will be 0 on return. If the $whence argument is supplied, it will be filled in with the sending socket address if possible. If the $flags argument is not supplied, it defaults to 0. If the $maxlen argument is not supplied, it is defaulted to the receive buffer size of the associated filehandle (if known), or the preferred blocksize of the associated filehandle (if known, which it usually won't be), or 8192.
ckeof
$whence
$flags
$maxlen
($nfound, $timeleft, $rbool, $wbool, $xbool) = $obj->select($doread, $dowrite, $doxcept, $timeout); $nfound = $obj->select($doread, $dowrite, $doxcept, $timeout);
Issues a 4-argument select() call for the associated I/O stream. All arguments are optional. The $timeout argument is the same as the fourth argument to the select() builtin. The first three are booleans, used to determine whether the method should include the object's I/O stream in the corresponding parameter to the select() call. The return in list context is the standard two values from select(), follwed by booleans indicating whether the actual select() call found reading, writing, or exception to be true. In scalar context, the routine returns only the count of the number of matching conditions. This is probably only useful when you're checking just one of the three possible conditions.
$ok = $obj->send($buffer, $flags, $destsockaddr); $ok = $obj->send($buffer, $flags); $ok = $obj->send($buffer);
This method calls the send() builtin (three- or four-argument form). The $flags parameter is defaulted to 0 if not supplied. If the $destsockaddr value is missing or undefined, and the socket is connected ($obj->isconnected returns true), then the three-argument form of the send() builtin will be used. Otherwise, the $destsockaddr parameter will be defaulted from the last recv() peer address for the same kind of message (depending on whether MSG_OOB is set in the $flags parameter). A defined $destsockaddr will result in a four-argument send() call. The return value from the send() builtin is returned. This method makes no attempt to trap SIGPIPE.
$destsockaddr
$obj->isconnected
MSG_OOB
$ok = $obj->sendto($buffer, $destsockaddr, $flags); $ok = $obj->sendto($buffer, $destsockaddr);
This method calls the send() builtin (four-argument form). The $flags parameter is defaulted to 0 if not supplied. The return value from the send() builtin is returned. This method makes no attempt to trap SIGPIPE.
$ok = $obj->setparam($key, $value, $newonly, $checkup); $ok = $obj->setparam($key, $value, $newonly); $ok = $obj->setparam($key, $value);
Sets a single new parameter. Uses the setparams method, and has the same rules for the handling of the $newonly and $checkup parameters. Returns 1 if the set was successful, and undef otherwise.
$newonly
$checkup
$ok = $obj->setparams(\%newparams, $newonly, $checkup); $ok = $obj->setparams(\%newparams, $newonly); $ok = $obj->setparams(\%newparams);
Sets new parameters from the given hashref, with validation. This is done in a loop over the key, value pairs from the newparams parameter. The precise nature of the validation depends on the $newonly and $checkup parameters (which are optional), but in all cases the keys to be set are checked against those registered with the object. If the $newonly parameter is negative, the value from the hashref will only be set if there is not already a defined value associated with that key, but the skipping of the setting of the value is silent. If the $newonly parameter is not negative or if there is no existing defined value, if the $checkup parameter is false then the setting of the new value is skipped if the new value is identical to the old value. If those checks don't cause the setting of a new value to be skipped, then if the $newonly parameter is positive and there is already a defined value for the specified key, a warning will be issued and the new value will not be set.
newparams
If none of the above checks cause the setting of a new value to be skipped, but if the specified key has a validation routine, that routine will be called with the given object, the current key, and the proposed new value as parameters. It is allowed for the validation routine to alter the new-value argument to change what will be set. (This is useful when changing a hostname to be in canonical form, for example.) If the validation routine returns a non-null string, that will be used to issue a warning, and the new value will not be set. If the validation routine returns a null string (or if there is no validation routine), the new value will (finally) get set for the given key.
The setparams method returns 1 if all parameters were successfully set, and undef otherwise.
$ok = $obj->setropt($level, $option, $rawvalue); $ok = $obj->setropt($optname, $rawvalue);
Returns the result from a call to the setsockopt() builtin. If the $level and $option arguments are both given as numbers, the setsockopt() call will be made even if the option is not registered with the object. Otherwise, unregistered options will fail as for the setsopt method, below.
$ok = $obj->setsopt($level, $option, @optvalues); $ok = $obj->setsopt($optname, @optvalues);
Returns the result from a call to the setsockopt() builtin. In order to be able to pack the @optvalues, the option must be registered with the object, just as described in "getsopt" above.
@optvalues
$ok = $obj->shutdown($how); $ok = $obj->shutdown;
Calls the shutdown() builtin on the filehandle associated with the object. This method is a no-op, returning 1, if the filehandle is not connected. The $how parameter is as per the shutdown() builtin, which in turn should be as described in the shutdown(2) manpage. If the $how parameter is not present, it is assumed to be SHUT_RDWR (which is 2 on most UNIX systems).
$how
SHUT_RDWR
Returns 1 if it has nothing to do, otherwise propagates the return from the shutdown() builtin.
$ok = $obj->stopio;
Calls the close() builtin on the filehandle associated with the object, unless that filehandle is already closed. Returns 1 or the return value from the close() builtin. This method is primarily for the use of server modules which need to avoid shutdown calls at inappropriate times. This method calls the delparams method for the keys of srcaddr and dstaddr.
$TIED_SCALAR = $data;
Provided for the support of tied scalars. Results in a call to the put method, unless there's exactly one arg and it's undef. In that case, since this normally results from undef $TIED_SCALAR, it's ignored.
undef $TIED_SCALAR
tie *FH, $package, @options or die; print FH $out_data; print $in_data while defined($in_data = <FH>); untie *FH;
Tieing of a filehandle to a network handle is supported by this base However, this method only succeeds if the related call to the new method returns an object for which the isconnected method returns true. Thus, the most useful example is in Net::UDP.
tie $x, $package, @options or die; $x = $out_data; print $in_data while defined($in_data = $x); untie $x;
Tieing of scalars to a network handle is supported by this base class. However, this method only succeeds if the related call to the new method returns an object for which the isconnected method returns true. Thus, the useful examples are in Net::TCP and Net::UDP.
$obj->unbind;
Removes any saved binding for the object. Unless the object is currently connected, this will result in a call to its close method, in order to ensure that any previous binding is removed. Even if the object is connected, the srcaddrlist object parameter is removed (via the object's delparams method). The return value from this method is indeterminate.
$was = $obj->wasconnected;
Returns true if the object has had a successful connect() completion since it was last opened. Returns false after a close() or on a new object. Also returns true if $obj->isconnecting is true.
$nwritten = $obj->WRITE($buf, $len); $nwritten = $obj->WRITE($buf, $len, $offset); $nwritten = syswrite(TIEDFH, $buf, $len); $nwritten = syswrite(TIEDFH, $buf, $len, $offset);
This method exists for support of syswrite() on tied filehandles. It calls the syswrite() builtin on the underlying filehandle with the same parameters.
Yes, I know that Perl doesn't really have protected methods as such. However, these are the methods which are only useful for implementing derived classes, and not for the general user.
$wasiteof = $obj->ckeof;
After a 0-length read in the get() routine, it calls this method to determine whether such a 0-length read meant EOF. The default method supplied here checks for non-blocking sockets (if necessary), and for a SOCK_STREAM socket. If EOF_NONBLOCK is true, or if the VAL_O_NONBLOCK flag was not set in the fcntl() flags for the socket, or if the error code was not VAL_EAGAIN, and the socket is of type SOCK_STREAM, then this method returns true. It returns a false value otherwise. This method is overridable for classes like Net::Dnet, which support SOCK_SEQPACKET and need to make a protocol-family-specific check to tell a 0-length packet from EOF.
VAL_O_NONBLOCK
Net::Dnet
SOCK_SEQPACKET
$classname->initsockopts($level, \%optiondesc);
Given a prototype optiondesc hash ref, updates it to include all the data needed for the values it can find, and deletes the ones it can't. For example, here's a single entry from such a prototype optiondesc:
'SO_LINGER' => ['II'],
Given that, and the $level of SOL_SOCKET, and the incoming class name of Net::Gen, initsockopts will attempt to evaluate SO_LINGER in package Net::Gen, and if it succeeds it will fill out the rest of the information in the associated array ref, and add another key to the hash ref for the value of SO_LINGER (which is 128 on my system). If it can't evaluate that psuedo-constant, it will simply delete that entry from the referenced hash. Assuming a successful evaluation of this entry, the resulting entries would look like this:
SOL_SOCKET
initsockopts
SO_LINGER
'SO_LINGER' => ['II', SO_LINGER+0, SOL_SOCKET+0, 2], SO_LINGER+0 => ['II', SO_LINGER+0, SOL_SOCKET+0, 2],
(All right, so the expressions would be known values, but maybe you get the idea.)
A completed optiondesc hash is a set of key-value pairs where the value is an array ref with the following elements:
[pack template, option value, option level, pack array len]
Such a completed optiondesc is one of the required arguments to the register_options method (see below).
register_options
$obj->register_options($levelname, $level, \%optiondesc);
This method attaches the socket options specified by the given option descriptions hash ref and the given level (as text and as a number) to the object. The registered set of socket options is in fact a hashref of hashrefs, where the keys are the level names and level numbers, and the values are the optiondesc hash refs which get registered.
Example:
$self->register_options('SOL_SOCKET', SOL_SOCKET+0, \%sockopts);
$obj->register_param_handlers(\@keynames, \@keyhandlers); $obj->register_param_handlers(\%key_handler_pairs);
This method registers the referenced keynames (if they haven't already been registered), and establishes the referenced keyhandlers as validation routines for those keynames. Each element of the keyhandlers array must be a code reference. When the setparams method invokes the handler, it will be called with three arguments: the target object, the keyname in question, and the proposed new value (which may be undef, especially if being called from the delparams method). See the other discussion of validation routines in the setparams method description, above.
$obj->register_param_keys(\@keynames);
This method registers the referenced keynames as valid parameters for setparams and the like for this object. The new methods can store arbitrary parameter values, but the init method will later ensure that all those keys eventually got registered. This out-of-order setup is allowed because of possible cross-dependencies between the various parameters, so they have to be set before they can be validated (in some cases).
$value = $obj->_accessor($what); $oldvalue = $obj->_accessor($what, $newvalue);
This method implements the use of the known parameter keys as get/set methods. It's used by the customised AUTOLOAD to generate such accessor functions as they're referenced. See "blocking" above for an example.
These are the socket options known to the Net::Gen module itself:
SO_ACCEPTCONN, SO_BROADCAST, SO_DEBUG, SO_DONTROUTE, SO_ERROR, SO_EXPANDED_RIGHTS, SO_FAMILY, SO_KEEPALIVE, SO_LINGER, SO_OOBINLINE, SO_PAIRABLE, SO_RCVBUF, SO_RCVLOWAT, SO_RCVTIMEO, SO_REUSEADDR, SO_REUSEPORT, SO_SNDBUF, SO_SNDLOWAT, SO_SNDTIMEO, SO_STATE, SO_TYPE, SO_USELOOPBACK, SO_XSE
SO_ACCEPTCONN
SO_BROADCAST
SO_DEBUG
SO_DONTROUTE
SO_ERROR
SO_EXPANDED_RIGHTS
SO_FAMILY
SO_KEEPALIVE
SO_OOBINLINE
SO_PAIRABLE
SO_RCVBUF
SO_RCVLOWAT
SO_RCVTIMEO
SO_REUSEADDR
SO_REUSEPORT
SO_SNDBUF
SO_SNDLOWAT
SO_SNDTIMEO
SO_STATE
SO_TYPE
SO_USELOOPBACK
SO_XSE
These are the object parameters registered by the Net::Gen module itself:
Address family (will default from PF, and vice versa).
Set to 0 when a socket has been marked as non-blocking, and to 1 otherwise. If it's undef, it'll be treated as though it were set to 1. The use of anything which even looks like stdio calls on non-blocking sockets as at your own risk. If you don't know how to work with non-blocking sockets already, the results of trying them may surprise you.
The result of getpeername(), or an ephemeral proposed connect() address.
A reference to an array of socket addresses to try for connect().
An override of the default maximum queue depth parameter for listen(). This will be used if the $maxqueue argument to listen() is not supplied.
This parameter is set true to keep the connect method from really calling the connect() built-in if the socket has not had an source address specified and it is not bound. This is used by the Net::UNIX and Net::UDP modules to keep from exercising a bug in some socket implementations with respect to how datagram sockets are handled. (This was specifically done in response to quirks of Solaris 2.5.1.) Instead, the connect method simply sets the dstaddr object parameter, which the send method will respect.
Protocol family for this object. Will default from AF, and vice versa.
The protocol to pass to the socket() call (often defaulted to 0).
A boolean, indicating whether the bind method should do a setsockopt() call to set SO_REUSEADDR to 1.
A boolean, indicating whether the bind method should do a setsockopt() call to set SO_REUSEPORT to 1.
The result of getsockname(), or an ephemeral proposed bind() address.
A reference to an array of socket addresses to try for bind().
The maximum time to wait for connect() or accept() attempts to succeed. See the discussion of timeouts and non-blocking sockets in "connect" above.
The socket type to create (SOCK_STREAM, SOCK_DGRAM, etc.)
SOCK_DGRAM
$connect_address = pack_sockaddr($family, $fam_addr);
Returns a packed struct sockaddr corresponding to the provided $family (which must be a number) and the address-family-specific $fam_addr (pre-packed).
struct sockaddr
($family, $fam_addr) = unpack_sockaddr($packed_address);
The inverse of pack_sockaddr().
Various socket-related errno values. See ":errnos" for the list. These routines will always be defined, but they will return 0 if the corresponding error symbol was not found on your system.
errno
Returns a boolean value depending on whether a read from a non-blocking socket can distinguish an end-of-file condition from a no-data-available condition. This corresponds to the value available from the Config module as $Config::Config{'d_eofnblk'}), except that EOF_NONBLOCK is always defined.
Config
$Config::Config{'d_eofnblk'}
EOF_NONBLOCK
Gives the integer return value found by the Configure script for a read() system call on a non-blocking socket which has no data available. This is similar to the string representation of the value available from the Config module as $Config::Config{'rd_nodata'}.
$Config::Config{'rd_nodata'}
Gives the value of the error symbol found by the Configure script which is set by a non-blocking filehandle when no data is available. This differs from the value available from the Config module ($Config::Config{'eagain'}) in that the latter is a string, typically "EAGAIN".
$Config::Config{'eagain'}
"EAGAIN"
Gives the value found by the Configure script for setting a filehandle non-blocking. The value available from the Config module is a string representing the value found ($Config::Config{'o_nonblock'}), whereas the value from VAL_O_NONBLOCK is an integer, suitable for passing to sysopen() or for eventual use in fcntl().
$Config::Config{'o_nonblock'}
None.
AF_APPLETALK AF_CCITT AF_CHAOS AF_CTF AF_DATAKIT AF_DECnet AF_DLI AF_ECMA AF_HYLINK AF_IMPLINK AF_INET AF_ISO AF_LAST AF_LAT AF_LINK AF_LOCAL AF_NETMAN AF_NS AF_OSI AF_PUP AF_ROUTE AF_SNA AF_UNIX AF_UNSPEC AF_USER AF_WAN AF_X25 EADDRINUSE EADDRNOTAVAIL EAFNOSUPPORT EAGAIN EALREADY EBADF EBADMSG ECONNABORTED ECONNREFUSED ECONNRESET EDESTADDRREQ EHOSTDOWN EHOSTUNREACH EINPROGRESS EINVAL EISCONN EMSGSIZE ENETDOWN ENETRESET ENETUNREACH ENOBUFS ENODATA ENOENT ENOPROTOOPT ENOSR ENOSTR ENOTCONN ENOTSOCK EOF_NONBLOCK EOPNOTSUPP EPFNOSUPPORT EPROTO EPROTONOSUPPORT EPROTOTYPE ESHUTDOWN ESOCKTNOSUPPORT ETIME ETIMEDOUT ETOOMANYREFS EWOULDBLOCK pack_sockaddr PF_APPLETALK PF_CCITT PF_CHAOS PF_CTF PF_DATAKIT PF_DECnet PF_DLI PF_ECMA PF_HYLINK PF_IMPLINK PF_INET PF_ISO PF_LAST PF_LAT PF_LINK PF_LOCAL PF_NETMAN PF_NS PF_OSI PF_PUP PF_ROUTE PF_SNA PF_UNIX PF_UNSPEC PF_USER PF_WAN PF_X25 RD_NODATA SHUT_RD SHUT_RDWR SHUT_WR SOCK_DGRAM SOCK_RAW SOCK_RDM SOCK_SEQPACKET SOCK_STREAM SOL_SOCKET SOMAXCONN SO_ACCEPTCONN SO_BROADCAST SO_DEBUG SO_DONTROUTE SO_ERROR SO_EXPANDED_RIGHTS SO_FAMILY SO_KEEPALIVE SO_LINGER SO_OOBINLINE SO_PAIRABLE SO_RCVBUF SO_RCVLOWAT SO_RCVTIMEO SO_REUSEADDR SO_REUSEPORT SO_SNDBUF SO_SNDLOWAT SO_SNDTIMEO SO_STATE SO_TYPE SO_USELOOPBACK SO_XSE unpack_sockaddr VAL_EAGAIN VAL_O_NONBLOCK
AF_APPLETALK
AF_CCITT
AF_CHAOS
AF_CTF
AF_DATAKIT
AF_DECnet
AF_DLI
AF_ECMA
AF_HYLINK
AF_IMPLINK
AF_INET
AF_ISO
AF_LAST
AF_LAT
AF_LINK
AF_LOCAL
AF_NETMAN
AF_NS
AF_OSI
AF_PUP
AF_ROUTE
AF_SNA
AF_UNIX
AF_UNSPEC
AF_USER
AF_WAN
AF_X25
EADDRINUSE
EADDRNOTAVAIL
EAFNOSUPPORT
EAGAIN
EALREADY
EBADF
EBADMSG
ECONNABORTED
ECONNREFUSED
ECONNRESET
EDESTADDRREQ
EHOSTDOWN
EHOSTUNREACH
EINPROGRESS
EISCONN
EMSGSIZE
ENETDOWN
ENETRESET
ENETUNREACH
ENOBUFS
ENODATA
ENOENT
ENOPROTOOPT
ENOSR
ENOSTR
ENOTCONN
ENOTSOCK
EOPNOTSUPP
EPFNOSUPPORT
EPROTO
EPROTONOSUPPORT
EPROTOTYPE
ESHUTDOWN
ESOCKTNOSUPPORT
ETIME
ETIMEDOUT
ETOOMANYREFS
EWOULDBLOCK
pack_sockaddr
PF_APPLETALK
PF_CCITT
PF_CHAOS
PF_CTF
PF_DATAKIT
PF_DECnet
PF_DLI
PF_ECMA
PF_HYLINK
PF_IMPLINK
PF_INET
PF_ISO
PF_LAST
PF_LAT
PF_LINK
PF_LOCAL
PF_NETMAN
PF_NS
PF_OSI
PF_PUP
PF_ROUTE
PF_SNA
PF_UNIX
PF_UNSPEC
PF_USER
PF_WAN
PF_X25
RD_NODATA
SHUT_RD
SHUT_WR
SOCK_RAW
SOCK_RDM
unpack_sockaddr
VAL_EAGAIN
The following :tags are available for grouping exported items together:
AF_APPLETALK AF_CCITT AF_CHAOS AF_CTF AF_DATAKIT AF_DECnet AF_DLI AF_ECMA AF_HYLINK AF_IMPLINK AF_INET AF_ISO AF_LAST AF_LAT AF_LINK AF_LOCAL AF_NETMAN AF_NS AF_OSI AF_PUP AF_ROUTE AF_SNA AF_UNIX AF_UNSPEC AF_USER AF_WAN AF_X25
EADDRINUSE EADDRNOTAVAIL EAFNOSUPPORT EAGAIN EALREADY EBADF EBADMSG ECONNABORTED ECONNREFUSED ECONNRESET EDESTADDRREQ EHOSTDOWN EHOSTUNREACH EINPROGRESS EINVAL EISCONN EMSGSIZE ENETDOWN ENETRESET ENETUNREACH ENOBUFS ENODATA ENOENT ENOPROTOOPT ENOSR ENOSTR ENOTCONN ENOTSOCK EOPNOTSUPP EPFNOSUPPORT EPROTO EPROTONOSUPPORT EPROTOTYPE ESHUTDOWN ESOCKTNOSUPPORT ETIME ETIMEDOUT ETOOMANYREFS EWOULDBLOCK
The union of the :af and :pf tags.
:af
:pf
EOF_NONBLOCK RD_NODATA VAL_EAGAIN VAL_O_NONBLOCK
PF_APPLETALK PF_CCITT PF_CHAOS PF_CTF PF_DATAKIT PF_DECnet PF_DLI PF_ECMA PF_HYLINK PF_IMPLINK PF_INET PF_ISO PF_LAST PF_LAT PF_LINK PF_LOCAL PF_NETMAN PF_NS PF_OSI PF_PUP PF_ROUTE PF_SNA PF_UNIX PF_UNSPEC PF_USER PF_WAN PF_X25
pack_sockaddr unpack_sockaddr
SHUT_RD SHUT_WR SHUT_RDWR
SO_ACCEPTCONN SO_BROADCAST SO_DEBUG SO_DONTROUTE SO_ERROR SO_EXPANDED_RIGHTS SO_FAMILY SO_KEEPALIVE SO_LINGER SO_OOBINLINE SO_PAIRABLE SO_RCVBUF SO_RCVLOWAT SO_RCVTIMEO SO_REUSEADDR SO_REUSEPORT SO_SNDBUF SO_SNDLOWAT SO_SNDTIMEO SO_STATE SO_TYPE SO_USELOOPBACK SO_XSE
SOL_SOCKET SOCK_STREAM SOCK_DGRAM SOCK_RAW SOCK_RDM SOCK_SEQPACKET
All of the above.
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.
Net::Inet(3), Net::UNIX(3), Net::Dnet(3)
Spider Boardman <spidb@cpan.org>
To install Net::TCP, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Net::TCP
CPAN shell
perl -MCPAN -e shell install Net::TCP
For more information on module installation, please visit the detailed CPAN module installation guide.