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=head1 NAME |
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|
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AnyEvent::MP::Transport - actual transport protocol |
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|
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=head1 SYNOPSIS |
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|
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use AnyEvent::MP::Transport; |
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|
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=head1 DESCRIPTION |
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|
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This is the superclass for MP transports, most of which is considered an |
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implementation detail. |
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|
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See the "PROTOCOL" section below if you want to write another client for |
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this protocol. |
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|
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=head1 FUNCTIONS/METHODS |
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|
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=over 4 |
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|
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=cut |
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|
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package AnyEvent::MP::Transport; |
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|
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use common::sense; |
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|
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use Scalar::Util; |
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use MIME::Base64 (); |
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use Storable (); |
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use JSON::XS (); |
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|
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use AE (); |
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use AnyEvent::Socket (); |
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use AnyEvent::Handle (); |
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|
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use base Exporter::; |
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|
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our $VERSION = '0.0'; |
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our $PROTOCOL_VERSION = 0; |
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|
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=item $listener = mp_listener $host, $port, <constructor-args>, $cb->($transport) |
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|
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Creates a listener on the given host/port using |
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C<AnyEvent::Socket::tcp_server>. |
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|
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See C<new>, below, for constructor arguments. |
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|
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Defaults for peerhost, peerport, fh and tls are provided. |
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|
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=cut |
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|
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sub mp_server($$@) { |
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my $cb = pop; |
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my ($host, $port, @args) = @_; |
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|
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AnyEvent::Socket::tcp_server $host, $port, sub { |
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my ($fh, $host, $port) = @_; |
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|
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$cb->(new AnyEvent::MP::Transport |
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fh => $fh, |
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peerhost => $host, |
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peerport => $port, |
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tls => "accept", |
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@args, |
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); |
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} |
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} |
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|
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=item $guard = mp_connect $host, $port, <constructor-args>, $cb->($transport) |
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|
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=cut |
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|
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sub mp_connect { |
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my $cb = pop; |
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my ($host, $port, @args) = @_; |
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|
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AnyEvent::Socket::tcp_connect $host, $port, sub { |
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my ($fh, $nhost, $nport) = @_; |
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|
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return $cb->() unless $fh; |
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|
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$cb->(new AnyEvent::MP::Transport |
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fh => $fh, |
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peername => $host, |
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peerhost => $nhost, |
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peerport => $nport, |
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tls => "accept", |
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@args, |
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); |
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} |
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} |
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|
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=item new AnyEvent::MP::Transport |
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|
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# immediately starts negotiation |
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my $transport = new AnyEvent::MP::Transport |
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# mandatory |
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fh => $filehandle, |
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local_id => $identifier, |
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on_recv => sub { receive-callback }, |
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on_error => sub { error-callback }, |
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|
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# optional |
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secret => "shared secret", |
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on_eof => sub { clean-close-callback }, |
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on_connect => sub { successful-connect-callback }, |
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greeting => { key => value }, |
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|
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# tls support |
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tls => "accept|connect", |
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tls_ctx => AnyEvent::TLS, |
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peername => $peername, # for verification |
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; |
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|
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=cut |
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|
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our @FRAMINGS = qw(json storable); # the framing types we accept and send, in order of preference |
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our @AUTH_SND = qw(hmac_md6_64_256); # auth types we send |
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our @AUTH_RCV = (@AUTH_SND, qw(hex_secret)); # auth types we accept |
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|
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#AnyEvent::Handle::register_write_type mp_record => sub { |
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#}; |
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|
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sub new { |
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my ($class, %arg) = @_; |
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|
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my $self = bless \%arg, $class; |
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|
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$self->{queue} = []; |
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|
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{ |
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Scalar::Util::weaken (my $self = $self); |
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|
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if (exists $arg{connect}) { |
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$arg{tls} ||= "connect"; |
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$arg{tls_ctx} ||= { sslv2 => 0, sslv3 => 0, tlsv1 => 1, verify => 1 }; |
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} |
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|
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$arg{secret} = AnyEvent::MP::Base::default_secret () |
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unless exists $arg{secret}; |
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|
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$self->{hdl} = new AnyEvent::Handle |
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fh => delete $arg{fh}, |
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rbuf_max => 64 * 1024, |
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autocork => 1, |
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no_delay => 1, |
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on_error => sub { |
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$self->error ($_[2]); |
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}, |
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peername => delete $arg{peername}, |
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; |
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|
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my $secret = $arg{secret}; |
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my $greeting_kv = $self->{greeting} ||= {}; |
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$greeting_kv->{"tls1.0"} ||= $arg{tls} |
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if exists $arg{tls} && $arg{tls_ctx}; |
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$greeting_kv->{provider} = "AE-$VERSION"; |
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$greeting_kv->{peeraddr} = AnyEvent::Socket::format_hostport $self->{peerhost}, $self->{peerport}; |
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|
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# send greeting |
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my $lgreeting1 = "aemp;$PROTOCOL_VERSION;$PROTOCOL_VERSION" # version, min |
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. ";$AnyEvent::MP::Base::UNIQ" |
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. ";$AnyEvent::MP::Base::NODE" |
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. ";" . (join ",", @AUTH_RCV) |
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. ";" . (join ",", @FRAMINGS) |
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. (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv); |
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my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Base::nonce (33), ""; |
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|
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$self->{hdl}->push_write ("$lgreeting1\012$lgreeting2\012"); |
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|
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# expect greeting |
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$self->{hdl}->push_read (line => sub { |
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my $rgreeting1 = $_[1]; |
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|
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my ($aemp, $version, $version_min, $uniq, $rnode, $auths, $framings, @kv) = split /;/, $rgreeting1; |
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|
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if ($aemp ne "aemp") { |
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return $self->error ("unparsable greeting"); |
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} elsif ($version_min > $PROTOCOL_VERSION) { |
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return $self->error ("version mismatch (we: $PROTOCOL_VERSION, they: $version_min .. $version)"); |
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} |
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|
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my $s_auth; |
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for my $auth_ (split /,/, $auths) { |
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if (grep $auth_ eq $_, @AUTH_SND) { |
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$s_auth = $auth_; |
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last; |
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} |
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} |
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|
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defined $s_auth |
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or return $self->error ("$auths: no common auth type supported"); |
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|
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die unless $s_auth eq "hmac_md6_64_256"; # hardcoded atm. |
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|
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my $s_framing; |
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for my $framing_ (split /,/, $framings) { |
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if (grep $framing_ eq $_, @FRAMINGS) { |
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$s_framing = $framing_; |
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last; |
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} |
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} |
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|
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defined $s_framing |
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or return $self->error ("$framings: no common framing method supported"); |
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|
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$self->{remote_uniq} = $uniq; |
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$self->{remote_node} = $rnode; |
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|
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$self->{remote_greeting} = { |
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map /^([^=]+)(?:=(.*))?/ ? ($1 => $2) : (), |
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@kv |
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}; |
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|
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if (exists $self->{tls} and $self->{tls_ctx} and exists $self->{remote_greeting}{"tls1.0"}) { |
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if ($self->{tls} ne $self->{remote_greeting}{"tls1.0"}) { |
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return $self->error ("TLS server/client mismatch"); |
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} |
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$self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx}); |
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} |
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|
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# read nonce |
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$self->{hdl}->push_read (line => sub { |
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my $rgreeting2 = $_[1]; |
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|
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# auth |
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require Digest::MD6; |
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require Digest::HMAC_MD6; |
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|
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my $key = Digest::MD6::md6_hex ($secret); |
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my $lauth = Digest::HMAC_MD6::hmac_md6_base64 ($key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256); |
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|
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my $rauth = |
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$s_auth eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_base64 ($key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256) |
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: $s_auth eq "hex_secret" ? unpack "H*", $secret |
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: die; |
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|
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$lauth ne $rauth # echo attack? |
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or return $self->error ("authentication error"); |
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|
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$self->{hdl}->push_write ("$s_auth;$lauth;$s_framing\012"); |
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|
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$self->{hdl}->rbuf_max (64); # enough for 44 reply bytes or so |
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$self->{hdl}->push_read (line => sub { |
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my ($hdl, $rline) = @_; |
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|
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my ($auth_method, $rauth2, $r_framing) = split /;/, $rline; |
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|
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if ($rauth2 ne $rauth) { |
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return $self->error ("authentication failure/shared secret mismatch"); |
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} |
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|
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$self->{s_framing} = $s_framing; |
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|
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$hdl->rbuf_max (undef); |
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my $queue = delete $self->{queue}; # we are connected |
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|
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$self->connected; |
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|
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$hdl->push_write ($self->{s_framing} => $_) |
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for @$queue; |
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|
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my $rmsg; $rmsg = sub { |
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$_[0]->push_read ($r_framing => $rmsg); |
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|
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AnyEvent::MP::Base::_inject ($_[1]); |
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}; |
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$hdl->push_read ($r_framing => $rmsg); |
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}); |
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}); |
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}); |
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} |
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|
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$self |
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} |
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|
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sub error { |
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my ($self, $msg) = @_; |
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|
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if ($self->{node} && $self->{node}{transport} == $self) { |
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$self->{node}->clr_transport; |
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} |
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$AnyEvent::MP::Base::WARN->("$self->{peerhost}:$self->{peerport}: $msg"); |
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$self->destroy; |
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} |
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|
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sub connected { |
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my ($self) = @_; |
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|
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my $node = AnyEvent::MP::Base::add_node ($self->{remote_node}); |
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Scalar::Util::weaken ($self->{node} = $node); |
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$node->set_transport ($self); |
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} |
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|
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sub send { |
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$_[0]{hdl}->push_write ($_[0]{s_framing} => $_[1]); |
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} |
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|
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sub destroy { |
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my ($self) = @_; |
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|
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$self->{hdl}->destroy |
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if $self->{hdl}; |
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} |
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|
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sub DESTROY { |
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my ($self) = @_; |
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|
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$self->destroy; |
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} |
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|
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=back |
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|
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=head1 PROTOCOL |
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|
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The protocol is relatively simple, and consists of three phases which are |
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symmetrical for both sides: greeting (followed by optionally switching to |
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TLS mode), authentication and packet exchange. |
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|
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the protocol is designed to allow both full-text and binary streams. |
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|
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The greeting consists of two text lines that are ended by either an ASCII |
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CR LF pair, or a single ASCII LF (recommended). |
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|
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=head2 GREETING |
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|
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The first line contains strings seperated (not ended) by C<;> |
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characters. The first seven strings are fixed by the protocol, the |
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remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;> |
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characters themselves. |
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|
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The seven fixed strings are: |
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|
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=over 4 |
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|
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=item C<aemp> |
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|
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The constant C<aemp> to identify the protocol. |
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|
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=item protocol version |
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|
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The (maximum) protocol version supported by this end, currently C<0>. |
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|
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=item minimum protocol version |
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|
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The minimum protocol version supported by this end, currently C<0>. |
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|
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=item a token uniquely identifying the current node instance |
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|
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This is a string that must change between restarts. It usually contains |
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things like the current time, the (OS) process id or similar values, but |
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no meaning of the contents are assumed. |
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|
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=item the node endpoint descriptors |
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|
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for public nodes, this is a comma-separated list of protocol endpoints, |
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i.e., the noderef. For slave nodes, this is a unique identifier. |
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|
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=item the acceptable authentication methods |
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|
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A comma-separated list of authentication methods supported by the |
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node. Note that AnyEvent::MP supports a C<hex_secret> authentication |
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method that accepts a cleartext password (hex-encoded), but will not use |
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this auth method itself. |
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|
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The receiving side should choose the first auth method it supports. |
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|
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=item the acceptable framing formats |
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|
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A comma-separated list of packet encoding/framign formats understood. The |
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receiving side should choose the first framing format it supports for |
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sending packets (which might be different from the format it has to accept). |
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|
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. ";$self->{peerhost};$self->{peerport}" |
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. (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv); |
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my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Base::nonce (33), ""; |
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=head1 SEE ALSO |
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|
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L<AnyEvent>. |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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|
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=cut |
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|
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1 |
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|
