mirror of
https://github.com/OpenVPN/openvpn3.git
synced 2024-09-20 20:13:05 +02:00
662bf7833e
Triple DES, and other 64-bit block-size ciphers vulnerable to "Sweet32" birthday attack (CVE-2016-6329). Limit such cipher keys to no more than 64 MB of data encrypted/decrypted. While our overall goal is to limit data-limited keys to 64 MB, we trigger a renegotiation at 48 MB to compensate for possible delays in renegotiation and rollover to the new key. This client-side implementation extends data limit protection to the entire session, even when the server doesn't implement data limits. This capability is advertised to servers via the a peer info setting: IV_BS64DL=1 meaning "Block-Size 64-bit Data Limit". The "1" indicates the implementation version. The implementation currently has some limitations: * Keys are renegotiated at a maximum rate of once per 5 seconds to reduce the likelihood of loss of synchronization between peers. * The maximum renegotiation rate may be further extended if the peer delays rollover from the old to new key after renegotiation. Added N_KEY_LIMIT_RENEG stats counter to count the number of data-limit-triggered renegotiations. Added new stats counter KEY_STATE_ERROR which roughly corresponds to the OpenVPN 2.x error "TLS Error: local/remote TLS keys are out of sync". Prevously, the TLS ack/retransmit timeout was hardcoded to 2 seconds. Now we lower the default to 1 second and make it variable using the (pushable) "tls-timeout" directive. Additionally, the tls-timeout directive can be specified in milliseconds instead of seconds by using the "tls-timeout-ms" form of the directive. Made the "become primary" time duration configurable via the (pushable) "become-primary" directive which accepts a number-of-seconds parameter. become-primary indicates the time delay between renegotiation and rollover to the new key for encryption/transmission. become-primary defaults to the handshake-window which in turn defaults to 60 seconds. Incremented core version to 3.0.20.
648 lines
16 KiB
C++
648 lines
16 KiB
C++
// OpenVPN -- An application to securely tunnel IP networks
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// over a single port, with support for SSL/TLS-based
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// session authentication and key exchange,
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// packet encryption, packet authentication, and
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// packet compression.
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//
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// Copyright (C) 2012-2015 OpenVPN Technologies, Inc.
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License Version 3
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// as published by the Free Software Foundation.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program in the COPYING file.
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// If not, see <http://www.gnu.org/licenses/>.
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// OpenVPN protocol implementation for client-instance object on server
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#ifndef OPENVPN_SERVER_SERVPROTO_H
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#define OPENVPN_SERVER_SERVPROTO_H
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#include <utility> // for std::move
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#include <openvpn/common/size.hpp>
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#include <openvpn/common/exception.hpp>
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#include <openvpn/common/rc.hpp>
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#include <openvpn/common/unicode.hpp>
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#include <openvpn/common/abort.hpp>
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#include <openvpn/common/link.hpp>
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#include <openvpn/buffer/bufstream.hpp>
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#include <openvpn/time/asiotimer.hpp>
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#include <openvpn/time/coarsetime.hpp>
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#include <openvpn/crypto/cryptodc.hpp>
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#include <openvpn/ssl/proto.hpp>
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#include <openvpn/transport/server/transbase.hpp>
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#include <openvpn/tun/server/tunbase.hpp>
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#include <openvpn/server/manage.hpp>
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#ifdef OPENVPN_DEBUG_SERVPROTO
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#define OPENVPN_LOG_SERVPROTO(x) OPENVPN_LOG(x)
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#else
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#define OPENVPN_LOG_SERVPROTO(x)
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#endif
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namespace openvpn {
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class ServerProto
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{
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typedef ProtoContext Base;
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typedef Link<TransportClientInstanceSend, TransportClientInstanceRecv> TransportLink;
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typedef Link<TunClientInstanceSend, TunClientInstanceRecv> TunLink;
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typedef Link<ManClientInstanceSend, ManClientInstanceRecv> ManLink;
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public:
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class Session;
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class Factory : public TransportClientInstanceFactory
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{
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public:
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typedef RCPtr<Factory> Ptr;
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typedef Base::Config ProtoConfig;
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Factory(asio::io_context& io_context_arg,
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const Base::Config& c)
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: io_context(io_context_arg)
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{
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if (c.tls_auth_enabled())
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preval.reset(new Base::TLSAuthPreValidate(c, true));
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}
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virtual TransportClientInstanceRecv::Ptr new_client_instance();
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virtual bool validate_initial_packet(const Buffer& net_buf)
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{
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if (preval)
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{
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const bool ret = preval->validate(net_buf);
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if (!ret)
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stats->error(Error::TLS_AUTH_FAIL);
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return ret;
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}
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else
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return true;
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}
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ProtoConfig::Ptr clone_proto_config() const
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{
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return new ProtoConfig(*proto_context_config);
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}
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asio::io_context& io_context;
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ProtoConfig::Ptr proto_context_config;
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ManClientInstanceFactory::Ptr man_factory;
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TunClientInstanceFactory::Ptr tun_factory;
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SessionStats::Ptr stats;
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private:
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Base::TLSAuthPreValidate::Ptr preval;
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};
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// This is the main server-side client instance object
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class Session : Base, // OpenVPN protocol implementation
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public TransportLink, // Transport layer
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public TunLink, // Tun/routing layer
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public ManLink // Management layer
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{
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friend class Factory; // calls constructor
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typedef Base::PacketType PacketType;
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using Base::now;
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using Base::stat;
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public:
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typedef RCPtr<Session> Ptr;
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virtual bool defined() const
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{
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return defined_();
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}
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virtual TunClientInstanceRecv* override_tun(TunClientInstanceSend* tun)
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{
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TunLink::send.reset(tun);
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return this;
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}
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virtual void start(const TransportClientInstanceSend::Ptr& parent,
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const PeerAddr::Ptr& addr,
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const int local_peer_id)
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{
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TransportLink::send = parent;
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peer_addr = addr;
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// init OpenVPN protocol handshake
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Base::update_now();
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Base::reset();
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Base::set_local_peer_id(local_peer_id);
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Base::start();
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Base::flush(true);
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// coarse wakeup range
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housekeeping_schedule.init(Time::Duration::binary_ms(512), Time::Duration::binary_ms(1024));
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}
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virtual PeerStats stats_poll()
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{
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if (TransportLink::send)
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return TransportLink::send->stats_poll();
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else
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return PeerStats();
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}
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virtual void stop()
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{
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if (!halt)
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{
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halt = true;
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housekeeping_timer.cancel();
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// deliver final peer stats to management layer
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if (TransportLink::send && ManLink::send)
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{
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if (TransportLink::send->stats_pending())
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ManLink::send->stats_notify(TransportLink::send->stats_poll(), true);
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}
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Base::pre_destroy();
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Base::reset_dc_factory();
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if (TransportLink::send)
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{
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TransportLink::send->stop();
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TransportLink::send.reset();
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}
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if (TunLink::send)
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{
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TunLink::send->stop();
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TunLink::send.reset();
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}
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if (ManLink::send)
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{
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ManLink::send->stop();
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ManLink::send.reset();
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}
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}
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}
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// called with OpenVPN-encapsulated packets from transport layer
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virtual bool transport_recv(BufferAllocated& buf)
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{
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bool ret = false;
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try {
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OPENVPN_LOG_SERVPROTO("Transport RECV[" << buf.size() << "] " << client_endpoint_render() << ' ' << Base::dump_packet(buf));
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// update current time
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Base::update_now();
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// get packet type
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Base::PacketType pt = Base::packet_type(buf);
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// process packet
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if (pt.is_data())
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{
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// data packet
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ret = Base::data_decrypt(pt, buf);
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if (buf.size())
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{
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#ifdef OPENVPN_PACKET_LOG
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log_packet(buf, false);
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#endif
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// make packet appear as incoming on tun interface
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if (true) // fixme: was tun
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{
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OPENVPN_LOG_SERVPROTO("TUN SEND[" << buf.size() << ']');
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// fixme -- code me
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}
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}
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// do a lightweight flush
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Base::flush(false);
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}
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else if (pt.is_control())
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{
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// control packet
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ret = Base::control_net_recv(pt, std::move(buf));
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// do a full flush
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Base::flush(true);
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}
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// schedule housekeeping wakeup
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set_housekeeping_timer();
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}
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catch (const std::exception& e)
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{
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error(e);
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ret = false;
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}
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return ret;
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}
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// called with cleartext IP packets from routing layer
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virtual void tun_recv(BufferAllocated& buf)
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{
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// fixme -- code me
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}
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// Return true if keepalive parameter(s) are enabled.
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virtual bool is_keepalive_enabled() const
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{
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return Base::is_keepalive_enabled();
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}
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// Disable keepalive for rest of session, but fetch
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// the keepalive parameters (in seconds).
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virtual void disable_keepalive(unsigned int& keepalive_ping,
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unsigned int& keepalive_timeout)
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{
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Base::disable_keepalive(keepalive_ping, keepalive_timeout);
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}
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// override the data channel factory
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virtual void override_dc_factory(const CryptoDCFactory::Ptr& dc_factory)
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{
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Base::dc_settings().set_factory(dc_factory);
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}
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virtual ~Session()
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{
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// fatal error if destructor called while Session is active
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if (defined_())
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std::abort();
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}
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private:
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Session(asio::io_context& io_context_arg,
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const Factory& factory,
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ManClientInstanceFactory::Ptr man_factory_arg,
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TunClientInstanceFactory::Ptr tun_factory_arg)
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: Base(factory.clone_proto_config(), factory.stats),
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io_context(io_context_arg),
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halt(false),
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did_push(false),
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did_client_halt_restart(false),
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housekeeping_timer(io_context_arg),
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disconnect_at(Time::infinite()),
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stats(factory.stats),
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man_factory(man_factory_arg),
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tun_factory(tun_factory_arg)
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{}
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bool defined_() const
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{
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return !halt && TransportLink::send;
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}
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// proto base class calls here for control channel network sends
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virtual void control_net_send(const Buffer& net_buf)
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{
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OPENVPN_LOG_SERVPROTO("Transport SEND[" << net_buf.size() << "] " << client_endpoint_render() << ' ' << Base::dump_packet(net_buf));
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if (TransportLink::send)
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{
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if (TransportLink::send->transport_send_const(net_buf))
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Base::update_last_sent();
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}
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}
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// Called on server with credentials and peer info provided by client.
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// Should be overriden by derived class if credentials are required.
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virtual void server_auth(const std::string& username,
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const SafeString& password,
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const std::string& peer_info,
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const AuthCert::Ptr& auth_cert)
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{
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constexpr size_t MAX_USERNAME_SIZE = 256;
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constexpr size_t MAX_PASSWORD_SIZE = 256;
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if (get_management())
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{
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AuthCreds::Ptr auth_creds(new AuthCreds(Unicode::utf8_printable(username, MAX_USERNAME_SIZE|Unicode::UTF8_FILTER),
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Unicode::utf8_printable(password, MAX_PASSWORD_SIZE|Unicode::UTF8_FILTER),
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Unicode::utf8_printable(peer_info, Unicode::UTF8_FILTER|Unicode::UTF8_PASS_FMT)));
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ManLink::send->auth_request(auth_creds, auth_cert, peer_addr);
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}
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}
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// proto base class calls here for app-level control-channel messages received
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virtual void control_recv(BufferPtr&& app_bp)
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{
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const std::string msg = Unicode::utf8_printable(Base::template read_control_string<std::string>(*app_bp),
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Unicode::UTF8_FILTER);
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if (msg == "PUSH_REQUEST")
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{
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if (!did_push)
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{
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did_push = true;
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if (get_management())
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ManLink::send->push_request(Base::conf_ptr());
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else
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{
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auth_failed("no management provider", false);
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}
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}
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}
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else
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{
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OPENVPN_LOG("Unrecognized client request: " << msg);
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}
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}
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virtual void auth_failed(const std::string& reason,
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const bool tell_client)
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{
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push_halt_restart_msg(HaltRestart::AUTH_FAILED, reason, tell_client);
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}
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virtual void set_fwmark(const unsigned int fwmark)
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{
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if (TunLink::send)
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TunLink::send->set_fwmark(fwmark);
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}
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virtual void push_reply(std::vector<BufferPtr>&& push_msgs,
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const std::vector<IP::Route>& rtvec,
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const unsigned int initial_fwmark)
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{
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if (halt)
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return;
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if (get_tun())
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{
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Base::init_data_channel();
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if (initial_fwmark)
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TunLink::send->set_fwmark(initial_fwmark);
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TunLink::send->add_routes(rtvec);
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for (auto &msg : push_msgs)
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{
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msg->null_terminate();
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Base::control_send(std::move(msg));
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}
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Base::flush(true);
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set_housekeeping_timer();
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}
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else
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{
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auth_failed("no tun provider", false);
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}
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}
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virtual void push_halt_restart_msg(const HaltRestart::Type type,
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const std::string& reason,
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const bool tell_client)
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{
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if (halt || did_client_halt_restart)
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return;
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Base::update_now();
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BufferPtr buf(new BufferAllocated(128, BufferAllocated::GROW));
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BufferStreamOut os(*buf);
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std::string ts;
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switch (type)
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{
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case HaltRestart::HALT:
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ts = "HALT";
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os << "HALT,";
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if (tell_client && !reason.empty())
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os << reason;
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else
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os << "client was disconnected from server";
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break;
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case HaltRestart::RESTART:
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ts = "RESTART";
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os << "RESTART,";
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if (tell_client && !reason.empty())
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os << reason;
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else
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os << "server requested a client reconnect";
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break;
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case HaltRestart::RESTART_PASSIVE:
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ts = "RESTART_PASSIVE";
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os << "RESTART,[P]:";
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if (tell_client && !reason.empty())
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os << reason;
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else
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os << "server requested a client reconnect";
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break;
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case HaltRestart::RESTART_PSID:
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ts = "RESTART_PSID";
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os << "RESTART,[P]:";
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if (tell_client && !reason.empty())
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os << reason;
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else
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os << "server requested a client reconnect";
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break;
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case HaltRestart::AUTH_FAILED:
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ts = "AUTH_FAILED";
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os << ts;
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if (tell_client && !reason.empty())
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os << ',' << reason;
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break;
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case HaltRestart::RAW:
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{
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const size_t pos = reason.find_first_of(',');
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if (pos != std::string::npos)
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ts = reason.substr(0, pos);
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else
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ts = reason;
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os << reason;
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break;
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}
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}
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OPENVPN_LOG("Disconnect: " << ts << ' ' << reason);
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if (type != HaltRestart::RESTART_PASSIVE)
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{
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did_client_halt_restart = true;
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disconnect_in(Time::Duration::seconds(1));
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}
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buf->null_terminate();
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Base::control_send(std::move(buf));
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Base::flush(true);
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set_housekeeping_timer();
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}
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virtual void post_info(BufferPtr&& info)
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{
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if (halt)
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return;
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Base::update_now();
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info->null_terminate();
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Base::control_send(std::move(info));
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Base::flush(true);
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set_housekeeping_timer();
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}
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virtual void stats_notify(const PeerStats& ps, const bool final)
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{
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if (ManLink::send)
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ManLink::send->stats_notify(ps, final);
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}
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virtual void float_notify(const PeerAddr::Ptr& addr)
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{
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if (ManLink::send)
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ManLink::send->float_notify(addr);
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}
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virtual void data_limit_notify(const int key_id,
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const DataLimit::Mode cdl_mode,
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const DataLimit::State cdl_status)
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{
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Base::update_now();
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Base::data_limit_notify(key_id, cdl_mode, cdl_status);
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Base::flush(true);
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set_housekeeping_timer();
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}
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bool get_management()
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{
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if (!ManLink::send)
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{
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if (man_factory)
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ManLink::send = man_factory->new_obj(this);
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}
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return bool(ManLink::send);
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}
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bool get_tun()
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{
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if (!TunLink::send)
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{
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if (tun_factory)
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TunLink::send = tun_factory->new_obj(this);
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}
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return bool(TunLink::send);
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}
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void disconnect_in(const Time::Duration& dur)
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{
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disconnect_at = now() + dur;
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}
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void housekeeping_callback(const asio::error_code& e)
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{
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try {
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if (!e && !halt)
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|
{
|
|
// update current time
|
|
Base::update_now();
|
|
|
|
housekeeping_schedule.reset();
|
|
Base::housekeeping();
|
|
if (Base::invalidated())
|
|
invalidation_error(Base::invalidation_reason());
|
|
else if (now() >= disconnect_at)
|
|
error("disconnect triggered");
|
|
else
|
|
set_housekeeping_timer();
|
|
}
|
|
}
|
|
catch (const std::exception& e)
|
|
{
|
|
error(e);
|
|
}
|
|
}
|
|
|
|
void set_housekeeping_timer()
|
|
{
|
|
Time next = Base::next_housekeeping();
|
|
next.min(disconnect_at);
|
|
if (!housekeeping_schedule.similar(next))
|
|
{
|
|
if (!next.is_infinite())
|
|
{
|
|
next.max(now());
|
|
housekeeping_schedule.reset(next);
|
|
housekeeping_timer.expires_at(next);
|
|
housekeeping_timer.async_wait([self=Ptr(this)](const asio::error_code& error)
|
|
{
|
|
self->housekeeping_callback(error);
|
|
});
|
|
}
|
|
else
|
|
{
|
|
housekeeping_timer.cancel();
|
|
}
|
|
}
|
|
}
|
|
|
|
std::string client_endpoint_render()
|
|
{
|
|
if (TransportLink::send)
|
|
return TransportLink::send->transport_info();
|
|
else
|
|
return "";
|
|
}
|
|
|
|
void error(const std::string& error)
|
|
{
|
|
OPENVPN_LOG("ServerProto: " << error);
|
|
stop();
|
|
}
|
|
|
|
void error(const std::exception& e)
|
|
{
|
|
error(e.what());
|
|
}
|
|
|
|
void error()
|
|
{
|
|
stop();
|
|
}
|
|
|
|
void invalidation_error(const Error::Type err)
|
|
{
|
|
switch (err)
|
|
{
|
|
case Error::KEV_NEGOTIATE_ERROR:
|
|
case Error::KEEPALIVE_TIMEOUT:
|
|
error();
|
|
break;
|
|
default:
|
|
error(std::string("Session invalidated: ") + Error::name(err));
|
|
break;
|
|
}
|
|
}
|
|
|
|
asio::io_context& io_context;
|
|
bool halt;
|
|
bool did_push;
|
|
bool did_client_halt_restart;
|
|
|
|
PeerAddr::Ptr peer_addr;
|
|
|
|
CoarseTime housekeeping_schedule;
|
|
AsioTimer housekeeping_timer;
|
|
|
|
Time disconnect_at;
|
|
|
|
SessionStats::Ptr stats;
|
|
|
|
ManClientInstanceFactory::Ptr man_factory;
|
|
TunClientInstanceFactory::Ptr tun_factory;
|
|
};
|
|
};
|
|
|
|
inline TransportClientInstanceRecv::Ptr ServerProto::Factory::new_client_instance()
|
|
{
|
|
return new Session(io_context, *this, man_factory, tun_factory);
|
|
}
|
|
}
|
|
|
|
#endif
|