AnyEvent-MP/MP/DataConn.pm

=head1 NAME

AnyEvent::MP::DataConn - create socket connections between nodes

=head1 SYNOPSIS

   use AnyEvent::MP::DataConn;

=head1 DESCRIPTION

This module can be used to create socket connections between the local and
a remote node in the aemp network. The socket can be used freely for any
purpose, and in most cases, this mechanism is a good way to transport big
chunks of binary data.

The connections created by this module use the same security mechanisms
as normal AEMP connections (secure authentication, optional use of TLS),
and in fact, use the same listening port as AEMP connections, so when two
nodes can reach each other via the normal aemp protocol, they can create
data connections as well, no extra ports or firewall rules are required.

The protocol used is, however, not the AEMP transport protocol, so this
will only work between nodes implementing the "aemp-dataconn" protocol
extension.

=head1 FUNCTIONS

=over 4

=cut

package AnyEvent::MP::DataConn;

use common::sense;
use Carp ();
use POSIX ();

use AnyEvent ();
use AnyEvent::Util ();

use AnyEvent::MP;
use AnyEvent::MP::Kernel ();
use AnyEvent::MP::Global ();

our $ID = "a";
our %STATE;

# another node tells us to await a connection
sub _expect {
   my ($id, $port, $timeout, $initfunc, @initdata) = @_;

   $STATE{$id} = {
      id   => $id,
      to   => (AE::timer $timeout, 0, sub {
         $STATE{$id}{done}(undef);
      }),
      done => sub {
         my ($hdl, $error) = @_;

         %{delete $STATE{$id}} = ();

         if (defined $hdl) {
            (AnyEvent::MP::Kernel::load_func $initfunc)->(@initdata, $hdl);
         } else {
            kil $port, AnyEvent::MP::DataConn:: => $error;
         }
      },
   };
}

# AEMP::Transport call for dataconn-connections
sub _inject {
   my ($conn, $error) = @_;

   my $hdl = defined $error ? undef : delete $conn->{hdl};
   my $id = $conn->{local_greeting}{dataconn_id} || $conn->{remote_greeting}{dataconn_id}
      or return;

   $conn->destroy;

   ($STATE{$id} or return)->{done}($hdl, $error);
}

# actively connect to some other node
sub _connect {
   my ($id, $node) = @_;

   my $state = $STATE{$id}
      or return;

   my $addr = $AnyEvent::MP::Global::addr{$node};

   @$addr
      or return $state->{done}(undef, "$node: no listeners found");

   # I love hardcoded constants  !
   $state->{next} = AE::timer 0, 2, sub {
      my $endpoint = shift @$addr
         or return delete $state->{next};

      my ($host, $port) = AnyEvent::Socket::parse_hostport $endpoint
         or return;

      my $transport; $transport = AnyEvent::MP::Transport::mp_connect
         $host, $port,
         protocol => "aemp-dataconn",
         local_greeting => { dataconn_id => $id },
         sub { $transport->destroy }, #TODO: destroys handshaked conenctions too early
      ;
   };
}

=item AnyEvent::MP::DataConn::connect_to $node, $timeout, $initfunc, @initdata, $cb->($handle)

Creates a socket connection between the local node and the node C<$node>
(which can also be specified as a port). One of the nodes must have
listening ports ("binds").

When the connection could be successfully created, the C<$initfunc>
will be called with the given C<@initdata> on the remote node (similar
to C<snd_to_func> or C<spawn>), and the C<AnyEvent::Handle> object
representing the remote connection end as additional argument.

Also, the callback given as last argument will be called with the
AnyEvent::Handle object for the local side.

The AnyEvent::Handle objects will be in a "quiescent" state - you could rip
out the file handle and forget about it, but it is recommended to use it,
as the security settings might have called for a TLS connection. If you
opt to use it, you at least have to set an C<on_error> callback.

In case of any error (timeout etc.), nothing will be called on
the remote side, and the local port will be C<kil>'ed with an C<<
AnyEvent::MP::DataConn => "error message" >> kill reason.

The timeout should be large enough to cover at least four network
round-trips and one message round-trip.

Example: on node1, establish a connection to node2 and send a line of text,
one node2, provide a receiver function.

   # node1, code executes in some port context
   AnyEvent::MP::DataConn::connect_to "node2", 5, "pkg::receiver", 1, sub {
      my ($hdl) = @_;
      warn "connection established, sending line.\n"
      $hdl->push_write ("blabla\n")
   };

   # node2
   sub pkg::receiver {
      my ($one, $hdl) = @_;
      warn "connection established, wait for a line...\n"

      $hdl->push_read (line => sub {
         warn "received a line: $_[1]\n";
         undef $hdl;
      });
   }

=cut

sub connect_to($$$$@) {
   my $cb = pop;
   my ($node, $timeout, $initfunc, @initdata) = @_;

   my $port = $SELF
      or Carp::croak "AnyEvent::MP::DataConn::connect_to must be called in port context";

   $node = node_of $node;

   my $id = (++$ID) . "\@$NODE";

   # damn, why do my simple state hashes resemble objects so quickly
   my $state = $STATE{$id} = {
      id   => (++$ID) . "\@$NODE",
      to   => (AE::timer $timeout, 0, sub {
         $STATE{$id}{done}(undef, "$node: unable to establish connection within $timeout seconds");
      }),
      done => sub {
         my ($hdl, $error) = @_;

         delete $AnyEvent::MP::Global::ON_SETUP{$id};
         %{delete $STATE{$id}} = ();

         if (defined $hdl) {
            $cb->($hdl);
         } else {
            kil $port, AnyEvent::MP::DataConn:: => $error;
         }
      },
   };

   if (AnyEvent::MP::Kernel::port_is_local $node) {
      # teh sucks

      require AnyEvent::Util;
      my ($fh1, $fh2) = AnyEvent::Util::portable_socketpair ()
         or return kil $port, AnyEvent::MP::DataConn:: => "cannot create local socketpair: $!";

      use AnyEvent::Handle;
      my $hdl1 = new AnyEvent::Handle fh => $fh1;
      my $hdl2 = new AnyEvent::Handle fh => $fh2;

      (AnyEvent::MP::Kernel::load_func $initfunc)->(@initdata, $hdl2);
      $cb->($hdl1);

   } else {
      AnyEvent::MP::Kernel::snd_to_func $node,
         AnyEvent::MP::DataConn::_expect:: => $id, $port, $timeout, $initfunc, @initdata;

      $state->{wait} = sub {
         if (my $addr = $AnyEvent::MP::Global::addr{$node}) {
            delete $AnyEvent::MP::Global::ON_SETUP{$id};

            # continue connect
            if (@$addr) {
               # node has listeners, so connect
               _connect $id, $node;
            } else {
               # no listeners, ask it to connect to us
               AnyEvent::MP::Kernel::snd_to_func $node, AnyEvent::MP::DataConn::_connect:: => $id, $NODE;
            }
         } else {
            # wait for the next global setup handshake
            # due to the round-trip at the beginning, this should never be necessary
            $AnyEvent::MP::Global::ON_SETUP{$id} = $state->{wait};
         };
      };

      # we actually have to make sure that the connection arrives after the expect message, and
      # the easiest way to do this is to use an rpc call.
      AnyEvent::MP::Kernel::snd_on $node, port { $state->{wait}() };
   }
}

=back

=head1 SEE ALSO

L<AnyEvent::MP>.

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

1

Revision:	1.8
Committed:	Tue Dec 1 11:59:48 2009 UTC (14 years, 6 months ago) by root
Branch:	MAIN
CVS Tags:	rel-1_28, rel-1_29, rel-1_24, rel-1_26, rel-1_27, rel-1_30
Changes since 1.7:	+2 -1 lines
Log Message:	* empty log message *
#	Content
1	=head1 NAME
2
3	AnyEvent::MP::DataConn - create socket connections between nodes
4
5	=head1 SYNOPSIS
6
7	use AnyEvent::MP::DataConn;
8
9	=head1 DESCRIPTION
10
11	This module can be used to create socket connections between the local and
12	a remote node in the aemp network. The socket can be used freely for any
13	purpose, and in most cases, this mechanism is a good way to transport big
14	chunks of binary data.
15
16	The connections created by this module use the same security mechanisms
17	as normal AEMP connections (secure authentication, optional use of TLS),
18	and in fact, use the same listening port as AEMP connections, so when two
19	nodes can reach each other via the normal aemp protocol, they can create
20	data connections as well, no extra ports or firewall rules are required.
21
22	The protocol used is, however, not the AEMP transport protocol, so this
23	will only work between nodes implementing the "aemp-dataconn" protocol
24	extension.
25
26	=head1 FUNCTIONS
27
28	=over 4
29
30	=cut
31
32	package AnyEvent::MP::DataConn;
33
34	use common::sense;
35	use Carp ();
36	use POSIX ();
37
38	use AnyEvent ();
39	use AnyEvent::Util ();
40
41	use AnyEvent::MP;
42	use AnyEvent::MP::Kernel ();
43	use AnyEvent::MP::Global ();
44
45	our $ID = "a";
46	our %STATE;
47
48	# another node tells us to await a connection
49	sub _expect {
50	my ($id, $port, $timeout, $initfunc, @initdata) = @_;
51
52	$STATE{$id} = {
53	id => $id,
54	to => (AE::timer $timeout, 0, sub {
55	$STATE{$id}{done}(undef);
56	}),
57	done => sub {
58	my ($hdl, $error) = @_;
59
60	%{delete $STATE{$id}} = ();
61
62	if (defined $hdl) {
63	(AnyEvent::MP::Kernel::load_func $initfunc)->(@initdata, $hdl);
64	} else {
65	kil $port, AnyEvent::MP::DataConn:: => $error;
66	}
67	},
68	};
69	}
70
71	# AEMP::Transport call for dataconn-connections
72	sub _inject {
73	my ($conn, $error) = @_;
74
75	my $hdl = defined $error ? undef : delete $conn->{hdl};
76	my $id = $conn->{local_greeting}{dataconn_id} \|\| $conn->{remote_greeting}{dataconn_id}
77	or return;
78
79	$conn->destroy;
80
81	($STATE{$id} or return)->{done}($hdl, $error);
82	}
83
84	# actively connect to some other node
85	sub _connect {
86	my ($id, $node) = @_;
87
88	my $state = $STATE{$id}
89	or return;
90
91	my $addr = $AnyEvent::MP::Global::addr{$node};
92
93	@$addr
94	or return $state->{done}(undef, "$node: no listeners found");
95
96	# I love hardcoded constants !
97	$state->{next} = AE::timer 0, 2, sub {
98	my $endpoint = shift @$addr
99	or return delete $state->{next};
100
101	my ($host, $port) = AnyEvent::Socket::parse_hostport $endpoint
102	or return;
103
104	my $transport; $transport = AnyEvent::MP::Transport::mp_connect
105	$host, $port,
106	protocol => "aemp-dataconn",
107	local_greeting => { dataconn_id => $id },
108	sub { $transport->destroy }, #TODO: destroys handshaked conenctions too early
109	;
110	};
111	}
112
113	=item AnyEvent::MP::DataConn::connect_to $node, $timeout, $initfunc, @initdata, $cb->($handle)
114
115	Creates a socket connection between the local node and the node C<$node>
116	(which can also be specified as a port). One of the nodes must have
117	listening ports ("binds").
118
119	When the connection could be successfully created, the C<$initfunc>
120	will be called with the given C<@initdata> on the remote node (similar
121	to C<snd_to_func> or C<spawn>), and the C<AnyEvent::Handle> object
122	representing the remote connection end as additional argument.
123
124	Also, the callback given as last argument will be called with the
125	AnyEvent::Handle object for the local side.
126
127	The AnyEvent::Handle objects will be in a "quiescent" state - you could rip
128	out the file handle and forget about it, but it is recommended to use it,
129	as the security settings might have called for a TLS connection. If you
130	opt to use it, you at least have to set an C<on_error> callback.
131
132	In case of any error (timeout etc.), nothing will be called on
133	the remote side, and the local port will be C<kil>'ed with an C<<
134	AnyEvent::MP::DataConn => "error message" >> kill reason.
135
136	The timeout should be large enough to cover at least four network
137	round-trips and one message round-trip.
138
139	Example: on node1, establish a connection to node2 and send a line of text,
140	one node2, provide a receiver function.
141
142	# node1, code executes in some port context
143	AnyEvent::MP::DataConn::connect_to "node2", 5, "pkg::receiver", 1, sub {
144	my ($hdl) = @_;
145	warn "connection established, sending line.\n"
146	$hdl->push_write ("blabla\n")
147	};
148
149	# node2
150	sub pkg::receiver {
151	my ($one, $hdl) = @_;
152	warn "connection established, wait for a line...\n"
153
154	$hdl->push_read (line => sub {
155	warn "received a line: $_[1]\n";
156	undef $hdl;
157	});
158	}
159
160	=cut
161
162	sub connect_to($$$$@) {
163	my $cb = pop;
164	my ($node, $timeout, $initfunc, @initdata) = @_;
165
166	my $port = $SELF
167	or Carp::croak "AnyEvent::MP::DataConn::connect_to must be called in port context";
168
169	$node = node_of $node;
170
171	my $id = (++$ID) . "\@$NODE";
172
173	# damn, why do my simple state hashes resemble objects so quickly
174	my $state = $STATE{$id} = {
175	id => (++$ID) . "\@$NODE",
176	to => (AE::timer $timeout, 0, sub {
177	$STATE{$id}{done}(undef, "$node: unable to establish connection within $timeout seconds");
178	}),
179	done => sub {
180	my ($hdl, $error) = @_;
181
182	delete $AnyEvent::MP::Global::ON_SETUP{$id};
183	%{delete $STATE{$id}} = ();
184
185	if (defined $hdl) {
186	$cb->($hdl);
187	} else {
188	kil $port, AnyEvent::MP::DataConn:: => $error;
189	}
190	},
191	};
192
193	if (AnyEvent::MP::Kernel::port_is_local $node) {
194	# teh sucks
195
196	require AnyEvent::Util;
197	my ($fh1, $fh2) = AnyEvent::Util::portable_socketpair ()
198	or return kil $port, AnyEvent::MP::DataConn:: => "cannot create local socketpair: $!";
199
200	use AnyEvent::Handle;
201	my $hdl1 = new AnyEvent::Handle fh => $fh1;
202	my $hdl2 = new AnyEvent::Handle fh => $fh2;
203
204	(AnyEvent::MP::Kernel::load_func $initfunc)->(@initdata, $hdl2);
205	$cb->($hdl1);
206
207	} else {
208	AnyEvent::MP::Kernel::snd_to_func $node,
209	AnyEvent::MP::DataConn::_expect:: => $id, $port, $timeout, $initfunc, @initdata;
210
211	$state->{wait} = sub {
212	if (my $addr = $AnyEvent::MP::Global::addr{$node}) {
213	delete $AnyEvent::MP::Global::ON_SETUP{$id};
214
215	# continue connect
216	if (@$addr) {
217	# node has listeners, so connect
218	_connect $id, $node;
219	} else {
220	# no listeners, ask it to connect to us
221	AnyEvent::MP::Kernel::snd_to_func $node, AnyEvent::MP::DataConn::_connect:: => $id, $NODE;
222	}
223	} else {
224	# wait for the next global setup handshake
225	# due to the round-trip at the beginning, this should never be necessary
226	$AnyEvent::MP::Global::ON_SETUP{$id} = $state->{wait};
227	};
228	};
229
230	# we actually have to make sure that the connection arrives after the expect message, and
231	# the easiest way to do this is to use an rpc call.
232	AnyEvent::MP::Kernel::snd_on $node, port { $state->{wait}() };
233	}
234	}
235
236	=back
237
238	=head1 SEE ALSO
239
240	L<AnyEvent::MP>.
241
242	=head1 AUTHOR
243
244	Marc Lehmann <schmorp@schmorp.de>
245	http://home.schmorp.de/
246
247	=cut
248
249	1
250