findroot.xpl

OpenCDN内容分发系统

<?xml version="1.0"?>
<!DOCTYPE methoddef SYSTEM "rpc-method.dtd">
<methoddef>
<name>FindRoot</name>
<version>1.1</version>
<signature>string struct</signature>
<help>
Description:
  Lets the Origin to poll FirstHop Transit candidates by UDP probing,
  in order to find the best root for distribution. It is invocated
  by RRDM as a FirstHop has to be found, and the result is communicated
  back to it

Accepts a struct containing:
   KEY               VALUE
   FH_n_r            array    FirstHop candidates
   FH_FP_r           array    their footprints
   FH_po_r           array    their ports
   AuthToken         int      token to authenticate method caller

Returns a struct containing:
   KEY               VALUE
   ret_code          int       numeric return code
   ret_val           string    message string
   index             string    Locates the best within the list
</help>
<code language="perl">
<![CDATA[
#!/usr/bin/perl
##############################################################################
#
#   Sub Name:         FindRoot
#
#   Description:      Lets the Origin to poll FirstHop Transit candidates
#                     by UDP probing, in order to find the best root for
#                     distribution. It is invocated by RRDM is a FirstHop
#                     has to be found, and the result is communicated
#                     back to it
#
# Accepts a struct containing:
#   KEY               VALUE
#   FH_n_r            array    FirstHop candidates
#   FH_FP_r           array    their footprints
#   FH_po_r           array    their ports
#   AuthToken         int      token to authenticate method caller
#
# Returns a struct containing:
#   KEY               VALUE
#   ret_code          int      numeric return code
#   ret_val           string   message string
#   index             string   Locates the best within the list
#
##############################################################################
sub FindRoot {

  use CommLib qw(node_log DBF_access find_best);

  require "$Origin::opt_c";
  OriginConfig->import(qw($origin_address));

  my $arg_r    = pop @_;
  my $FH_n_r   = $$arg_r{FH_n_r};
  my $FH_FP_r  = $$arg_r{FH_FP_r};
  my $FH_po_r  = $$arg_r{FH_po_r};
  my $hisToken = $$arg_r{AuthToken};

  my ($ret_code, $ret_val) = ('200', 'Origin did probed FirstHop candidates');
  my ($auth_token, $hr, $index) = (undef, undef, '');

  node_log ("FindRoot entered: FH_n, FH_FP, FH_po: @$FH_n_r, @$FH_FP_r, @$FH_po_r",
             1, 'o');

  $hr = DBF_access ("$Origin::origin_db", ['AuthToken'], 'r', 'o');

  if ( %$hr ) {
    $auth_token = $$hr{'AuthToken'};
  } else {
    $ret_code = '408';
    $ret_val  = 'Unable to retrieve AuthToken from DB_File';
    node_log ("FindRoot: $ret_code $ret_val", 1, 'o');
  }

  unless ( $ret_code ) {                   # sucessfull retrieval

    if ( $hisToken ne $auth_token ) {      # RRDM impostor unauthorized

      node_log ("$origin_address: FindRoot request unauthorized", 1, 'o');
      $ret_code  = '401';
      $ret_val   = 'Unauthorized';

    } else {                               # Caller authorized. Go on

      $index = find_best ($FH_n_r, $FH_po_r, $FH_FP_r, '',
                           $origin_address, '0', 'o');
    }
  }

  return { ret_code  => $ret_code,
           ret_val   => $ret_val,
           index     => $index };
}
__END__
]]></code>
</methoddef>