AnyEvent::Socket - useful IPv4 and IPv6 stuff. also unix domain sockets. and stuff.
use AnyEvent::Socket; tcp_connect "gameserver.deliantra.net", 13327, sub { my ($fh) = @_ or die "gameserver.deliantra.net connect failed: $!"; # enjoy your filehandle }; # a simple tcp server tcp_server undef, 8888, sub { my ($fh, $host, $port) = @_; syswrite $fh, "The internet is full, $host:$port. Go away!\015\012"; };
This module implements various utility functions for handling internet protocol addresses and sockets, in an as transparent and simple way as possible.
All functions documented without AnyEvent::Socket:: prefix are exported by default.
AnyEvent::Socket::
Tries to parse the given dotted quad IPv4 address and return it in octet form (or undef when it isn't in a parsable format). Supports all forms specified by POSIX (e.g. 10.0.0.1, 10.1, 10.0x020304, 0x12345678 or 0377.0377.0377.0377).
10.0.0.1
10.1
10.0x020304
0x12345678
0377.0377.0377.0377
Tries to parse the given IPv6 address and return it in octet form (or undef when it isn't in a parsable format).
Should support all forms specified by RFC 2373 (and additionally all IPv4 forms supported by parse_ipv4). Note that scope-id's are not supported (and will not parse).
This function works similarly to inet_pton AF_INET6, ....
inet_pton AF_INET6, ...
Example:
print unpack "H*", parse_ipv6 "2002:5345::10.0.0.1"; # => 2002534500000000000000000a000001
This fucntion exists mainly for symmetry to the other parse_protocol functions - it takes a hostname and, if it is unix/, it returns a special address token, otherwise undef.
parse_protocol
unix/
undef
The only use for this function is probably to detect whether a hostname matches whatever AnyEvent uses for unix domain sockets.
Combines parse_ipv4 and parse_ipv6 in one function. The address here refers to the host address (not socket address) in network form (binary).
parse_ipv4
parse_ipv6
If the $text is unix/, then this function returns a special token recognised by the other functions in this module to mean "UNIX domain socket".
$text
If the $text to parse is a mapped IPv4 in IPv6 address (:ffff::<ipv4>), then it will be treated as an IPv4 address. If you don't want that, you have to call parse_ipv4 and/or parse_ipv6 manually.
print unpack "H*", parse_address "10.1.2.3"; # => 0a010203
Same as parse_address, but not exported (think Socket::inet_aton but without name resolution).
parse_address
Socket::inet_aton
Works like the builtin function of the same name, except it tries hard to work even on broken platforms (well, that's windows), where getprotobyname is traditionally very unreliable.
Example: get the protocol number for TCP (usually 6)
my $proto = getprotobyname "tcp";
Splitting a string of the form hostname:port is a common problem. Unfortunately, just splitting on the colon makes it hard to specify IPv6 addresses and doesn't support the less common but well standardised [ip literal] syntax.
hostname:port
[ip literal]
This function tries to do this job in a better way, it supports (at least) the following formats, where port can be a numerical port number of a service name, or a name=port string, and the port and :port parts are optional. Also, everywhere where an IP address is supported a hostname or unix domain socket address is also supported (see parse_unix), and strings starting with / will also be interpreted as unix domain sockets.
port
name=port
:port
parse_unix
/
hostname:port e.g. "www.linux.org", "www.x.de:443", "www.x.de:https=443", ipv4:port e.g. "198.182.196.56", "127.1:22" ipv6 e.g. "::1", "affe::1" [ipv4or6]:port e.g. "[::1]", "[10.0.1]:80" [ipv4or6] port e.g. "[127.0.0.1]", "[www.x.org] 17" ipv4or6 port e.g. "::1 443", "10.0.0.1 smtp" unix/:path e.g. "unix/:/path/to/socket" /path e.g. "/path/to/socket"
It also supports defaulting the service name in a simple way by using $default_service if no service was detected. If neither a service was detected nor a default was specified, then this function returns the empty list. The same happens when a parse error was detected, such as a hostname with a colon in it (the function is rather conservative, though).
$default_service
print join ",", parse_hostport "localhost:443"; # => "localhost,443" print join ",", parse_hostport "localhost", "https"; # => "localhost,https" print join ",", parse_hostport "[::1]"; # => "," (empty list) print join ",", parse_host_port "/tmp/debug.sock"; # => "unix/", "/tmp/debug.sock"
Takes a host (in textual form) and a port and formats in unambigiously in a way that parse_hostport can parse it again. $port can be undef.
parse_hostport
$port
Returns the address family/protocol-family (AF_xxx/PF_xxx, in one value :) of the given host address in network format.
Expects a four octet string representing a binary IPv4 address and returns its textual format. Rarely used, see format_address for a nicer interface.
format_address
Expects a sixteen octet string representing a binary IPv6 address and returns its textual format. Rarely used, see format_address for a nicer interface.
Covnvert a host address in network format (e.g. 4 octets for IPv4 or 16 octets for IPv6) and convert it into textual form.
Returns unix/ for UNIX domain sockets.
This function works similarly to inet_ntop AF_INET || AF_INET6, ..., except it automatically detects the address type.
inet_ntop AF_INET || AF_INET6, ...
Returns undef if it cannot detect the type.
If the $ipn is a mapped IPv4 in IPv6 address (:ffff::<ipv4>), then just the contained IPv4 address will be returned. If you do not want that, you have to call format_ipv6 manually.
$ipn
format_ipv6
print format_address "\x01\x02\x03\x05"; => 1.2.3.5
Same as format_address, but not exported (think inet_ntoa).
inet_ntoa
Works similarly to its Socket counterpart, except that it uses a callback. Use the length to distinguish between ipv4 and ipv6 (4 octets for IPv4, 16 for IPv6), or use format_address to convert it to a more readable format.
Note that resolve_sockaddr, while initially a more complex interface, resolves host addresses, IDNs, service names and SRV records and gives you an ordered list of socket addresses to try and should be preferred over inet_aton.
resolve_sockaddr
inet_aton
Example.
inet_aton "www.google.com", my $cv = AE::cv; say unpack "H*", $_ for $cv->recv; # => d155e363 # => d155e367 etc. inet_aton "ipv6.google.com", my $cv = AE::cv; say unpack "H*", $_ for $cv->recv; # => 20014860a00300000000000000000068
Pack the given port/host combination into a binary sockaddr structure. Handles both IPv4 and IPv6 host addresses, as well as UNIX domain sockets ($host == unix/ and $service == absolute pathname).
$host
$service
my $bind = AnyEvent::Socket::pack_sockaddr 43, v195.234.53.120; bind $socket, $bind or die "bind: $!";
Unpack the given binary sockaddr structure (as used by bind, getpeername etc.) into a $service, $host combination.
$service, $host
For IPv4 and IPv6, $service is the port number and $host the host address in network format (binary).
For UNIX domain sockets, $service is the absolute pathname and $host is a special token that is understood by the other functions in this module (format_address converts it to unix/).
Tries to resolve the given nodename and service name into protocol families and sockaddr structures usable to connect to this node and service in a protocol-independent way. It works remotely similar to the getaddrinfo posix function.
For internet addresses, $node is either an IPv4 or IPv6 address, an internet hostname (DNS domain name or IDN), and $service is either a service name (port name from /etc/services) or a numerical port number. If both $node and $service are names, then SRV records will be consulted to find the real service, otherwise they will be used as-is. If you know that the service name is not in your services database, then you can specify the service in the format name=port (e.g. http=80).
$node
http=80
If a host cannot be found via DNS, then it will be looked up in /etc/hosts (or the file specified via $ENV{PERL_ANYEVENT_HOSTS}). If they are found, the addresses there will be used. The effect is as if entries from /etc/hosts would yield A and AAAA records for the host name unless DNS already had records for them.
$ENV{PERL_ANYEVENT_HOSTS}
A
AAAA
For UNIX domain sockets, $node must be the string unix/ and $service must be the absolute pathname of the socket. In this case, $proto will be ignored.
$proto
$proto must be a protocol name, currently tcp, udp or sctp. The default is currently tcp, but in the future, this function might try to use other protocols such as sctp, depending on the socket type and any SRV records it might find.
tcp
udp
sctp
$family must be either 0 (meaning any protocol is OK), 4 (use only IPv4) or 6 (use only IPv6). The default is influenced by $ENV{PERL_ANYEVENT_PROTOCOLS}.
$family
0
4
6
$ENV{PERL_ANYEVENT_PROTOCOLS}
$type must be SOCK_STREAM, SOCK_DGRAM or SOCK_SEQPACKET (or undef in which case it gets automatically chosen to be SOCK_STREAM unless $proto is udp).
$type
SOCK_STREAM
SOCK_DGRAM
SOCK_SEQPACKET
The callback will receive zero or more array references that contain $family, $type, $proto for use in socket and a binary $sockaddr for use in connect (or bind).
$family, $type, $proto
socket
$sockaddr
connect
bind
The application should try these in the order given.
resolve_sockaddr "google.com", "http", 0, undef, undef, sub { ... };
This is a convenience function that creates a TCP socket and makes a 100% non-blocking connect to the given $host (which can be a DNS/IDN hostname or a textual IP address, or the string unix/ for UNIX domain sockets) and $service (which can be a numeric port number or a service name, or a servicename=portnumber string, or the pathname to a UNIX domain socket).
servicename=portnumber
If both $host and $port are names, then this function will use SRV records to locate the real target(s).
In either case, it will create a list of target hosts (e.g. for multihomed hosts or hosts with both IPv4 and IPv6 addresses) and try to connect to each in turn.
After the connection is established, then the $connect_cb will be invoked with the socket file handle (in non-blocking mode) as first, and the peer host (as a textual IP address) and peer port as second and third arguments, respectively. The fourth argument is a code reference that you can call if, for some reason, you don't like this connection, which will cause tcp_connect to try the next one (or call your callback without any arguments if there are no more connections). In most cases, you can simply ignore this argument.
$connect_cb
tcp_connect
$cb->($filehandle, $host, $port, $retry)
If the connect is unsuccessful, then the $connect_cb will be invoked without any arguments and $! will be set appropriately (with ENXIO indicating a DNS resolution failure).
$!
ENXIO
The callback will never be invoked before tcp_connect returns, even if tcp_connect was able to connect immediately (e.g. on unix domain sockets).
The file handle is perfect for being plugged into AnyEvent::Handle, but can be used as a normal perl file handle as well.
Unless called in void context, tcp_connect returns a guard object that will automatically cancel the connection attempt when it gets destroyed - in which case the callback will not be invoked. Destroying it does not do anything to the socket after the connect was successful - you cannot "uncall" a callback that has been invoked already.
Sometimes you need to "prepare" the socket before connecting, for example, to bind it to some port, or you want a specific connect timeout that is lower than your kernel's default timeout. In this case you can specify a second callback, $prepare_cb. It will be called with the file handle in not-yet-connected state as only argument and must return the connection timeout value (or 0, undef or the empty list to indicate the default timeout is to be used).
$prepare_cb
Note to the poor Microsoft Windows users: Windows (of course) doesn't correctly signal connection errors, so unless your event library works around this, failed connections will simply hang. The only event libraries that handle this condition correctly are EV and Glib. Additionally, AnyEvent works around this bug with Event and in its pure-perl backend. All other libraries cannot correctly handle this condition. To lessen the impact of this windows bug, a default timeout of 30 seconds will be imposed on windows. Cygwin is not affected.
Simple Example: connect to localhost on port 22.
tcp_connect localhost => 22, sub { my $fh = shift or die "unable to connect: $!"; # do something };
Complex Example: connect to www.google.com on port 80 and make a simple GET request without much error handling. Also limit the connection timeout to 15 seconds.
tcp_connect "www.google.com", "http", sub { my ($fh) = @_ or die "unable to connect: $!"; my $handle; # avoid direct assignment so on_eof has it in scope. $handle = new AnyEvent::Handle fh => $fh, on_error => sub { AE::log error => $_[2]; $_[0]->destroy; }, on_eof => sub { $handle->destroy; # destroy handle AE::log info => "Done."; }; $handle->push_write ("GET / HTTP/1.0\015\012\015\012"); $handle->push_read (line => "\015\012\015\012", sub { my ($handle, $line) = @_; # print response header print "HEADER\n$line\n\nBODY\n"; $handle->on_read (sub { # print response body print $_[0]->rbuf; $_[0]->rbuf = ""; }); }); }, sub { my ($fh) = @_; # could call $fh->bind etc. here 15 };
Example: connect to a UNIX domain socket.
tcp_connect "unix/", "/tmp/.X11-unix/X0", sub { ... }
Create and bind a stream socket to the given host address and port, set the SO_REUSEADDR flag (if applicable) and call listen. Unlike the name implies, this function can also bind on UNIX domain sockets.
listen
For internet sockets, $host must be an IPv4 or IPv6 address (or undef, in which case it binds either to 0 or to ::, depending on whether IPv4 or IPv6 is the preferred protocol, and maybe to both in future versions, as applicable).
::
To bind to the IPv4 wildcard address, use 0, to bind to the IPv6 wildcard address, use ::.
The port is specified by $service, which must be either a service name or a numeric port number (or 0 or undef, in which case an ephemeral port will be used).
For UNIX domain sockets, $host must be unix/ and $service must be the absolute pathname of the socket. This function will try to unlink the socket before it tries to bind to it, and will try to unlink it after it stops using it. See SECURITY CONSIDERATIONS, below.
unlink
For each new connection that could be accepted, call the $accept_cb->($fh, $host, $port) with the file handle (in non-blocking mode) as first, and the peer host and port as second and third arguments (see tcp_connect for details).
accept
$accept_cb->($fh, $host, $port)
Croaks on any errors it can detect before the listen.
If called in non-void context, then this function returns a guard object whose lifetime it tied to the TCP server: If the object gets destroyed, the server will be stopped (but existing accepted connections will not be affected).
Regardless, when the function returns to the caller, the socket is bound and in listening state.
If you need more control over the listening socket, you can provide a $prepare_cb->($fh, $host, $port), which is called just before the listen () call, with the listen file handle as first argument, and IP address and port number of the local socket endpoint as second and third arguments.
$prepare_cb->($fh, $host, $port)
listen ()
It should return the length of the listen queue (or 0 for the default).
Note to IPv6 users: RFC-compliant behaviour for IPv6 sockets listening on :: is to bind to both IPv6 and IPv4 addresses by default on dual-stack hosts. Unfortunately, only GNU/Linux seems to implement this properly, so if you want both IPv4 and IPv6 listening sockets you should create the IPv6 socket first and then attempt to bind on the IPv4 socket, but ignore any EADDRINUSE errors.
EADDRINUSE
Example: bind on some TCP port on the local machine and tell each client to go away.
tcp_server undef, undef, sub { my ($fh, $host, $port) = @_; syswrite $fh, "The internet is full, $host:$port. Go away!\015\012"; }, sub { my ($fh, $thishost, $thisport) = @_; AE::log info => "Bound to $thishost, port $thisport."; };
Example: bind a server on a unix domain socket.
tcp_server "unix/", "/tmp/mydir/mysocket", sub { my ($fh) = @_; };
Enables (or disables) the TCP_NODELAY socket option (also known as Nagle's algorithm). Returns false on error, true otherwise.
TCP_NODELAY
Sets the tcp congestion avoidance algorithm (via the TCP_CONGESTION socket option). The default is OS-specific, but is usually reno. Typical other available choices include cubic, lp, bic, highspeed, htcp, hybla, illinois, scalable, vegas, veno, westwood and yeah.
TCP_CONGESTION
reno
cubic
lp
bic
highspeed
htcp
hybla
illinois
scalable
vegas
veno
westwood
yeah
This module is quite powerful, with with power comes the ability to abuse as well: If you accept "hostnames" and ports from untrusted sources, then note that this can be abused to delete files (host=unix/). This is not really a problem with this module, however, as blindly accepting any address and protocol and trying to bind a server or connect to it is harmful in general.
Marc Lehmann <schmorp@schmorp.de> http://anyevent.schmorp.de
To install AnyEvent, copy and paste the appropriate command in to your terminal.
cpanm
cpanm AnyEvent
CPAN shell
perl -MCPAN -e shell install AnyEvent
For more information on module installation, please visit the detailed CPAN module installation guide.