| 1 |
=head1 NAME |
| 2 |
|
| 3 |
AnyEvent::MP::Transport - actual transport protocol |
| 4 |
|
| 5 |
=head1 SYNOPSIS |
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|
| 7 |
use AnyEvent::MP::Transport; |
| 8 |
|
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=head1 DESCRIPTION |
| 10 |
|
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This is the superclass for MP transports, most of which is considered an |
| 12 |
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; |
| 28 |
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 |
| 44 |
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 and fh 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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@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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@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_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 = $self); |
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|
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#$arg{tls_ctx} ||= { sslv2 => 0, sslv3 => 0, tlsv1 => 1, verify => 1 }; |
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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->{"tls"} = "1.0" |
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if $arg{tls_ctx}; |
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$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 => $2) : (), |
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@kv |
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}; |
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|
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# read nonce |
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$self->{hdl}->push_read (line => sub { |
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my $rgreeting2 = $_[1]; |
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|
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if ($self->{tls_ctx} and 1 == int $self->{remote_greeting}{tls}) { |
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$self->{tls} = $lgreeting2 lt $rgreeting2 ? "connect" : "accept"; |
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$self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx}); |
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} |
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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 |
| 315 |
CR LF pair, or a single ASCII LF (recommended). |
| 316 |
|
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=head2 GREETING |
| 318 |
|
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The first line contains strings separated (not ended) by C<;> |
| 320 |
characters. The first seven strings are fixed by the protocol, the |
| 321 |
remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;> |
| 322 |
characters themselves. |
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|
| 324 |
The seven fixed strings are: |
| 325 |
|
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=over 4 |
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|
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=item C<aemp> |
| 329 |
|
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The constant C<aemp> to identify the protocol. |
| 331 |
|
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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>. |
| 335 |
|
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=item minimum protocol version |
| 337 |
|
| 338 |
The minimum protocol version supported by this end, currently C<0>. |
| 339 |
|
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=item a token uniquely identifying the current node instance |
| 341 |
|
| 342 |
This is a string that must change between restarts. It usually contains |
| 343 |
things like the current time, the (OS) process id or similar values, but |
| 344 |
no meaning of the contents are assumed. |
| 345 |
|
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=item the node endpoint descriptors |
| 347 |
|
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for public nodes, this is a comma-separated list of protocol endpoints, |
| 349 |
i.e., the noderef. For slave nodes, this is a unique identifier. |
| 350 |
|
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=item the acceptable authentication methods |
| 352 |
|
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A comma-separated list of authentication methods supported by the |
| 354 |
node. Note that AnyEvent::MP supports a C<hex_secret> authentication |
| 355 |
method that accepts a cleartext password (hex-encoded), but will not use |
| 356 |
this auth method itself. |
| 357 |
|
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The receiving side should choose the first auth method it supports. |
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|
| 360 |
=item the acceptable framing formats |
| 361 |
|
| 362 |
A comma-separated list of packet encoding/framign formats understood. The |
| 363 |
receiving side should choose the first framing format it supports for |
| 364 |
sending packets (which might be different from the format it has to accept). |
| 365 |
|
| 366 |
=back |
| 367 |
|
| 368 |
The remaining arguments are C<KEY=VALUE> pairs. The following key-value |
| 369 |
pairs are known at this time: |
| 370 |
|
| 371 |
=over 4 |
| 372 |
|
| 373 |
=item provider=<module-version> |
| 374 |
|
| 375 |
The software provider for this implementation. For AnyEvent::MP, this is |
| 376 |
C<AE-0.0> or whatever version it currently is at. |
| 377 |
|
| 378 |
=item peeraddr=<host>:<port> |
| 379 |
|
| 380 |
The peer address (socket address of the other side) as seen locally, in the same format |
| 381 |
as noderef endpoints. |
| 382 |
|
| 383 |
=item tls=<major>.<minor> |
| 384 |
|
| 385 |
Indicates that the other side supports TLS (version should be 1.0) and |
| 386 |
wishes to do a TLS handshake. |
| 387 |
|
| 388 |
=back |
| 389 |
|
| 390 |
After this greeting line there will be a second line containing a |
| 391 |
cryptographic nonce, i.e. random data of high quality. To keep the |
| 392 |
protocol text-only, these are usually 32 base64-encoded octets, but |
| 393 |
it could be anything that doesn't contain any ASCII CR or ASCII LF |
| 394 |
characters. |
| 395 |
|
| 396 |
Example of the two lines of greeting: |
| 397 |
|
| 398 |
aemp;0;0;e7d.4a76f48f;10.0.0.1:4040;hmac_md6_64_256,hex_secret;json,storable;provider=AE-0.0;peeraddr=127.0.0.1:1235 |
| 399 |
XntegV2Guvss0qNn7phCPnoU87xqxV+4Mqm/5y4iQm6a |
| 400 |
|
| 401 |
=head2 TLS handshake |
| 402 |
|
| 403 |
If, after the handshake, both sides indicate interest in TLS, then the |
| 404 |
connection I<must> use TLS, or fail. |
| 405 |
|
| 406 |
Both sides compare their nonces, and the side who sent the lower nonce |
| 407 |
value ("string" comparison on the raw octet values) becomes the client, |
| 408 |
and the one with the higher nonce the server. |
| 409 |
|
| 410 |
=head2 AUTHENTICATION PHASE |
| 411 |
|
| 412 |
After the greeting is received (and the optional TLS handshake), |
| 413 |
the authentication phase begins, which consists of sending a single |
| 414 |
C<;>-separated line with three fixed strings and any number of |
| 415 |
C<KEY=VALUE> pairs. |
| 416 |
|
| 417 |
The three fixed strings are: |
| 418 |
|
| 419 |
=over 4 |
| 420 |
|
| 421 |
=item the authentication method chosen |
| 422 |
|
| 423 |
This must be one of the methods offered by the other side in the greeting. |
| 424 |
|
| 425 |
=item the authentication data |
| 426 |
|
| 427 |
The authentication data itself, usually base64 or hex-encoded data. |
| 428 |
|
| 429 |
=item the framing protocol chosen |
| 430 |
|
| 431 |
This must be one of the framing protocols offered by the other side in the |
| 432 |
greeting. Each side must accept the choice of the other side. |
| 433 |
|
| 434 |
=back |
| 435 |
|
| 436 |
Example (the actual reply matching the previous example): |
| 437 |
|
| 438 |
hmac_md6_64_256;wIlLedBY956UCGSISG9mBZRDTG8xUi73/sVse2DSQp0;json |
| 439 |
|
| 440 |
=head2 DATA PHASE |
| 441 |
|
| 442 |
After this, packets get exchanged using the chosen framing protocol. It is |
| 443 |
quite possible that both sides use a different framing protocol. |
| 444 |
|
| 445 |
=head1 SEE ALSO |
| 446 |
|
| 447 |
L<AnyEvent>. |
| 448 |
|
| 449 |
=head1 AUTHOR |
| 450 |
|
| 451 |
Marc Lehmann <schmorp@schmorp.de> |
| 452 |
http://home.schmorp.de/ |
| 453 |
|
| 454 |
=cut |
| 455 |
|
| 456 |
1 |
| 457 |
|
