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Up to [LON-CAPA] / loncom / auth

- Bug 6876
  If node switched to from balancer can't connect to lond on user's
  homeserver, then session is switched to another node in the original list
  of usable nodes sent by the balancer.

# The LearningOnline Network
# Switch Servers Handler
#
# $Id: switchserver.pm,v 1.43 2018/11/28 05:05:30 raeburn Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#

package Apache::switchserver;

use strict;
use Apache::Constants qw(:common);
use Apache::lonnet;
use Apache::lonmenu;
use Digest::MD5 qw(md5_hex);
use CGI::Cookie();
use Apache::lonlocal;
use LONCAPA qw(:DEFAULT :match);

sub init_env {
    my ($r) = @_;
    
    if (-e $env{'user.environment'}) {
	return  $env{'user.environment'};
    }
    my $requrl=$r->uri;
    my $handle= &Apache::lonnet::check_for_valid_session($r);
    if ($handle ne '') {
	return undef;
    }
    my $lonidsdir=$r->dir_config('lonIDsDir');
    &Apache::lonnet::transfer_profile_to_env($lonidsdir,$handle);

    return $r->dir_config('lonIDsDir')."/$handle.id";
}

sub do_redirect {
    my ($r,$url,$only_body,$extra_text) = @_;
    $r->send_http_header;
    my $start_page = 
	&Apache::loncommon::start_page('Switching Server ...',undef,
				       {'redirect'       => [0.5,$url],
					'only_body'      => $only_body,});
    my $end_page   = &Apache::loncommon::end_page();
    $r->print($start_page.$extra_text.$end_page);
    unless ($env{'user.name'} eq 'public' && ($env{'user.domain'} eq 'public')) {
        $r->register_cleanup(\&flush_course_logs);
    }
    return OK;
}

sub flush_course_logs {
    &Apache::lonnet::flushcourselogs();
    return OK;
}

sub handler {
    my ($r) = @_;
    
    my $handle=&init_env($r);
    if (!defined($handle)) { return FORBIDDEN; }

    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
				['otherserver','role','origurl','symb']);

    my $switch_to=&Apache::lonnet::hostname($env{'form.otherserver'});
    if (! $env{'form.otherserver'}) {
	$env{'form.otherserver'} =	
	    &Apache::lonnet::find_existing_session($env{'user.domain'},
						   $env{'user.name'});
	if (! $env{'form.otherserver'}) {
	    $env{'form.otherserver'} = 
		&Apache::lonnet::spareserver(30000,undef,1);
	}
	$switch_to=&Apache::lonnet::hostname($env{'form.otherserver'});
    }

    if (!defined($switch_to)) { return FORBIDDEN; }

    my $protocol = 'http';
    if ($env{'form.otherserver'}) {
        if ($Apache::lonnet::protocol{$env{'form.otherserver'}} eq 'https') {
            $protocol = $Apache::lonnet::protocol{$env{'form.otherserver'}};
        }
    }

    if ($env{'user.name'} eq 'public'
	&& $env{'user.domain'} eq 'public') {
	my $url = $protocol.'://'.$switch_to.$r->uri;
        unlink($handle);
        #expire the cookie
        my $c = new CGI::Cookie(-name    => 'lonPubID',
                                -value   => '',
                                -expires => '-10y',);
        $r->header_out('Set-cookie' => $c);
	return &do_redirect($r,$url,1)
    }

    my $skip_canhost_check = '';
    if ($env{'form.role'}) {
        if (!exists($env{'user.role.'.$env{'form.role'}})) {
            delete($env{'form.role'});
        } else {
            my $now = time;
            my ($start,$end) = split(/\./,$env{'user.role.'.$env{'form.role'}});
            if (($start && $start > $now) || ($end && $end < $now)) {
                delete($env{'form.role'});
            } elsif ($env{'form.role'} eq 'au./'.$env{'user.domain'}.'/') {
                if (&Apache::lonnet::homeserver($env{'user.name'},$env{'user.domain'}) eq $env{'form.otherserver'}) {
                    $skip_canhost_check = 1;
                }
            } elsif ($env{'form.role'} =~ m{^[ac]a\./($match_domain)/($match_username)$}) {
                my ($audom,$auname) = ($1,$2);
                if (&Apache::lonnet::homeserver($auname,$audom) eq $env{'form.otherserver'}) {
                    if ((&Apache::lonnet::will_trust('othcoau',$audom,$env{'user.domain'})) &&
                        (&Apache::lonnet::will_trust('coremau',$env{'user.domain'},$audom))) {                             
                        $skip_canhost_check = 1;
                    }
                }
            }
        }
    }

    unless ($skip_canhost_check) {
        my $canhost = 1;
        my $uprimary_id = &Apache::lonnet::domain($env{'user.domain'},'primary');
        my $uint_dom = &Apache::lonnet::internet_dom($uprimary_id);
        my @intdoms;
        my $internet_names = &Apache::lonnet::get_internet_names($env{'form.otherserver'});
        if (ref($internet_names) eq 'ARRAY') {
            @intdoms = @{$internet_names};
        }
        unless ($uint_dom ne '' && grep(/^\Q$uint_dom\E$/,@intdoms)) {
            my $serverhomeID = &Apache::lonnet::get_server_homeID($switch_to);
            my $serverhomedom = &Apache::lonnet::host_domain($serverhomeID);
            my %defdomdefaults = &Apache::lonnet::get_domain_defaults($serverhomedom);
            my %udomdefaults = &Apache::lonnet::get_domain_defaults($env{'user.domain'});
            my $remoterev = &Apache::lonnet::get_server_loncaparev($env{'user.domain'},$env{'form.otherserver'});
            $canhost = 
                &Apache::lonnet::can_host_session($env{'user.domain'},
                                                  $env{'form.otherserver'},
                                                  $remoterev,
                                                  $udomdefaults{'remotesessions'},
                                                  $defdomdefaults{'hostedsessions'});
        }
        unless ($canhost) { return FORBIDDEN; }
    }

    #remove session env, and log event
    if (unlink($handle)) {
        if ($env{'user.linkedenv'} ne '') {
            my $lonidsdir=$r->dir_config('lonIDsDir');
            if (($env{'user.linkedenv'} =~ /^[a-f0-9]+_linked$/) &&
                (-l "$lonidsdir/$env{'user.linkedenv'}.id") &&
                (readlink("$lonidsdir/$env{'user.linkedenv'}.id") eq $handle)) {
                unlink("$lonidsdir/$env{'user.linkedenv'}.id");
            }
        }
    }
    my $now = time;
    my %temp=('switchserver' => $now.':'.$env{'form.otherserver'},
	      $env{'form.role'});
    &Apache::lonnet::put('email_status',\%temp);
    my $logmsg = "Switch Server to $env{'form.otherserver'}";
    if ($env{'form.role'}) {
        $logmsg .= " with role: $env{'form.role'}";
    } elsif (($env{'form.lti.reqcrs'}) && ($env{'form.lti.reqrole'} eq 'cc')) {
        $logmsg .= " to create new LTI course";
    } elsif ($env{'form.lti.selfenrollrole'}) {
        $logmsg .= " to selfenroll with role: $env{'form.lti.selfenrollrole'}";
    } else {
        $logmsg .= " (no role)";
    }
    $logmsg .= ' '.$ENV{'REMOTE_ADDR'};
    &Apache::lonnet::log($env{'user.domain'},$env{'user.name'},
			 $env{'user.home'},$logmsg);

    &Apache::loncommon::content_type($r,'text/html');

    #expire the cookies
    my %cookies=CGI::Cookie->parse($r->header_in('Cookie'));
    foreach my $name (keys(%cookies)) {
        next unless ($name =~ /^lon(|S|Link|Pub)ID$/);
        my $c = new CGI::Cookie(-name    => $name,
                                -value   => '',
                                -expires => '-10y',);
        $r->headers_out->add('Set-cookie' => $c);
    }
    if ($r->header_only) {
	$r->send_http_header;
	return OK;
    }
# -------------------------------------------------------- Menu script and info
	   
# ---------------------------------------------------------------- Get handover

    my $newcookieid;
    my ($is_balancer,$posshost,$setcookie,$offloadto,$dom_balancers) =
        &Apache::lonnet::check_loadbalancing($env{'user.name'},$env{'user.domain'});
    if ($is_balancer && $setcookie && $env{'form.otherserver'}) {

        # Set a balancer cookie unless browser already sent LON-CAPA load balancer
        # cookie which points at the target server
        my ($found_server,$balancer_cookie) = &Apache::lonnet::check_for_balancer_cookie($r,1);

        unless (($found_server eq $env{'form.otherserver'}) &&
                ($balancer_cookie =~ /^\Q$env{'user.domain'}\E_\Q$env{'user.name'}\E_/)) {
            my @hosts = &Apache::lonnet::current_machine_ids();
            my $desthost = $env{'form.otherserver'};
            unless (grep(/^\Q$desthost\E$/,@hosts)) {
                my $balancedir=$r->dir_config('lonBalanceDir');
                $newcookieid = &md5_hex(&md5_hex($now.{}.rand().$$));
                my $cookie = $env{'user.domain'}.'_'.$env{'user.name'}.'_'.$newcookieid;
                my $balcookie = "balanceID=$cookie; path=/; HttpOnly;";
                if (open(my $fh,'>',"$balancedir/$cookie.id")) {
                    print $fh $env{'form.otherserver'};
                    close($fh);
                }
                $r->headers_out->add('Set-cookie' => $balcookie);
            }
        }
    }

    my %info=('ip'            => $ENV{'REMOTE_ADDR'},
              'domain'        => $env{'user.domain'},
              'username'      => $env{'user.name'},
              'home'          => $env{'user.home'},
              'role'          => $env{'form.role'},
              'server'        => $r->dir_config('lonHostID'),
              'balancer'      => $is_balancer,
              'dom_balancers' => $dom_balancers,
              'offloadto'     => '');
    if (ref($offloadto) eq 'HASH') {
        foreach my $key (keys(%{$offloadto})) {
            if (ref($offloadto->{$key}) eq 'ARRAY') {
                $info{'offloadto'} .= $key.'='.join(',',@{$offloadto->{$key}}).'&';
            }
        }
        $info{'offloadto'} =~ s/\&$//;
    } elsif (ref($offloadto) eq 'ARRAY') {
        $info{'offloadto'} = join(',',@{$offloadto});
    }
    if ($newcookieid) {
        $info{'balcookie'} = $newcookieid;
    }
    if ($env{'form.origurl'}) {
        $info{'origurl'} = $env{'form.origurl'};
    }
    if ($env{'form.symb'}) {
        $info{'symb'} = $env{'form.symb'};
    }
    if ($env{'request.sso.login'}) {
	$info{'sso.login'} = $env{'request.sso.login'};
    }
    if ($env{'request.sso.reloginserver'}) {
        $info{'sso.reloginserver'} = $env{'request.sso.reloginserver'};
    }
    if ($env{'request.lti.login'}) {
        $info{'lti.login'} = $env{'request.lti.login'};
    }
    if ($env{'request.lti.uri'}) {
        $info{'lti.uri'} = $env{'request.lti.uri'};
    }
    if ($env{'request.lti.reqcrs'}) {
        $info{'lti.reqcrs'} = $env{'request.lti.reqcrs'};
    }
    if ($env{'request.lti.reqrole'}) {
        $info{'lti.reqrole'} = $env{'request.lti.reqrole'};
    }
    if ($env{'request.lti.selfenrollrole'}) {
        $info{'lti.selfenrollrole'} = $env{'request.lti.selfenrollrole'};
    }
    if ($env{'request.lti.sourcecrs'}) {
        $info{'lti.sourcecrs'} = $env{'request.lti.sourcecrs'};
    }
    if ($env{'request.lti.passbackid'}) {
        $info{'lti.passbackid'} = $env{'request.lti.passbackid'};
    }
    if ($env{'request.lti.passbackurl'}) {
        $info{'lti.passbackurl'} = $env{'request.lti.passbackurl'};
    }
    if ($env{'request.lti.rosterid'}) {
        $info{'lti.rosterid'} = $env{'request.lti.rosterid'};
    }
    if ($env{'request.lti.rosterurl'}) {
        $info{'lti.rosterurl'} = $env{'request.lti.rosterurl'};
    }
    if ($env{'request.lti.target'}) {
        $info{'lti.target'} = $env{'request.lti.target'};
    }
    my $token = &Apache::lonnet::tmpput(\%info,$env{'form.otherserver'});
    my $url =$protocol.'://'.$switch_to.'/adm/login?'.
	'domain='.$env{'user.domain'}.
	'&amp;username='.$env{'user.name'}.
	'&amp;token='.$token;
# --------------------------------------------------------------- Screen Output
    return &do_redirect($r, $url, 0);
}

1;
__END__