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318 lines
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C++

// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2012-2017 OpenVPN Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License Version 3
// as published by the Free Software Foundation.
//
// This program 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program in the COPYING file.
// If not, see <http://www.gnu.org/licenses/>.
// Generic, cross-platform tun interface that drives a TunBuilderBase API.
// Fully supports IPv6. To make this work on a given platform, define
// a TunBuilderBase for the platform.
#ifndef OPENVPN_TUN_BUILDER_CLIENT_H
#define OPENVPN_TUN_BUILDER_CLIENT_H
#include <memory>
#include <openvpn/tun/client/tunprop.hpp>
#include <openvpn/tun/persist/tunpersist.hpp>
#include <openvpn/common/scoped_fd.hpp>
#include <openvpn/tun/tunio.hpp>
namespace openvpn {
namespace TunBuilderClient {
OPENVPN_EXCEPTION(tun_builder_error);
// struct used to pass received tun packets
struct PacketFrom
{
typedef std::unique_ptr<PacketFrom> SPtr;
BufferAllocated buf;
};
// our TunPersist class, specialized for Unix file descriptors
typedef TunPersistTemplate<ScopedFD> TunPersist;
// A simplified tun interface where pre-existing
// socket is provided.
template <typename ReadHandler>
class Tun : public TunIO<ReadHandler, PacketFrom, openvpn_io::posix::stream_descriptor>
{
typedef TunIO<ReadHandler, PacketFrom, openvpn_io::posix::stream_descriptor> Base;
public:
typedef RCPtr<Tun> Ptr;
Tun(openvpn_io::io_context& io_context,
const int socket,
const bool retain_sd_arg,
const bool tun_prefix_arg,
ReadHandler read_handler_arg,
const Frame::Ptr& frame_arg,
const SessionStats::Ptr& stats_arg)
: Base(read_handler_arg, frame_arg, stats_arg)
{
Base::stream = new openvpn_io::posix::stream_descriptor(io_context, socket);
Base::name_ = "tun";
Base::retain_stream = retain_sd_arg;
Base::tun_prefix = tun_prefix_arg;
}
~Tun() { Base::stop(); }
};
// A factory for the Client class
class ClientConfig : public TunClientFactory
{
public:
typedef RCPtr<ClientConfig> Ptr;
TunProp::Config tun_prop;
int n_parallel; // number of parallel async reads on tun socket
bool retain_sd;
bool tun_prefix;
Frame::Ptr frame;
SessionStats::Ptr stats;
EmulateExcludeRouteFactory::Ptr eer_factory;
TunPersist::Ptr tun_persist;
TunBuilderBase* builder;
static Ptr new_obj()
{
return new ClientConfig;
}
TunClient::Ptr new_tun_client_obj(openvpn_io::io_context& io_context,
TunClientParent& parent,
TransportClient* transcli) override;
void finalize(const bool disconnected) override
{
if (disconnected)
tun_persist.reset();
}
private:
ClientConfig()
: n_parallel(8), retain_sd(false), tun_prefix(false), builder(nullptr) {}
};
// The tun interface
class Client : public TunClient
{
friend class ClientConfig; // calls constructor
friend class TunIO<Client*, PacketFrom, openvpn_io::posix::stream_descriptor>; // calls tun_read_handler
typedef Tun<Client*> TunImpl;
public:
virtual void tun_start(const OptionList& opt, TransportClient& transcli, CryptoDCSettings&) override
{
if (!impl)
{
halt = false;
if (config->tun_persist)
tun_persist = config->tun_persist; // long-term persistent
else
tun_persist.reset(new TunPersist(false, config->retain_sd, config->builder)); // short-term
try {
int sd = -1;
const IP::Addr server_addr = transcli.server_endpoint_addr();
// Check if persisted tun session matches properties of to-be-created session
if (tun_persist->use_persisted_tun(server_addr, config->tun_prop, opt))
{
sd = tun_persist->obj();
state = tun_persist->state();
OPENVPN_LOG("TunPersist: reused tun context");
// indicate reconnection with persisted state
config->builder->tun_builder_establish_lite();
}
else
{
TunBuilderBase* tb = config->builder;
// reset target tun builder object
if (!tb->tun_builder_new())
throw tun_builder_error("tun_builder_new failed");
// notify parent
parent.tun_pre_tun_config();
// configure the tun builder
TunProp::configure_builder(tb, state.get(), config->stats.get(), server_addr,
config->tun_prop, opt, config->eer_factory.get(), false);
// start tun
sd = tb->tun_builder_establish();
}
if (sd == -1)
{
parent.tun_error(Error::TUN_IFACE_CREATE, "cannot acquire tun interface socket");
return;
}
// persist state
if (tun_persist->persist_tun_state(sd, state))
OPENVPN_LOG("TunPersist: saving tun context:" << std::endl << tun_persist->options());
impl.reset(new TunImpl(io_context,
sd,
true,
config->tun_prefix,
this,
config->frame,
config->stats
));
impl->start(config->n_parallel);
// signal that we are connected
parent.tun_connected();
}
catch (const std::exception& e)
{
if (tun_persist)
tun_persist->close();
stop();
parent.tun_error(Error::TUN_SETUP_FAILED, e.what());
}
}
}
virtual bool tun_send(BufferAllocated& buf) override
{
return send(buf);
}
virtual std::string tun_name() const override
{
if (impl)
return impl->name();
else
return "UNDEF_TUN";
}
virtual std::string vpn_ip4() const override
{
if (state->vpn_ip4_addr.specified())
return state->vpn_ip4_addr.to_string();
else
return "";
}
virtual std::string vpn_ip6() const override
{
if (state->vpn_ip6_addr.specified())
return state->vpn_ip6_addr.to_string();
else
return "";
}
virtual std::string vpn_gw4() const override
{
if (state->vpn_ip4_gw.specified())
return state->vpn_ip4_gw.to_string();
else
return "";
}
virtual std::string vpn_gw6() const override
{
if (state->vpn_ip6_gw.specified())
return state->vpn_ip6_gw.to_string();
else
return "";
}
virtual void set_disconnect() override
{
if (tun_persist)
tun_persist->set_disconnect();
}
virtual void stop() override { stop_(); }
virtual ~Client() { stop_(); }
private:
Client(openvpn_io::io_context& io_context_arg,
ClientConfig* config_arg,
TunClientParent& parent_arg)
: io_context(io_context_arg),
config(config_arg),
parent(parent_arg),
halt(false),
state(new TunProp::State())
{
}
bool send(Buffer& buf)
{
if (impl)
return impl->write(buf);
else
return false;
}
void tun_read_handler(PacketFrom::SPtr& pfp) // called by TunImpl
{
parent.tun_recv(pfp->buf);
}
void tun_error_handler(const Error::Type errtype, // called by TunImpl
const openvpn_io::error_code* error)
{
}
void stop_()
{
if (!halt)
{
halt = true;
// stop tun
if (impl)
impl->stop();
tun_persist.reset();
}
}
openvpn_io::io_context& io_context;
TunPersist::Ptr tun_persist; // owns the tun socket descriptor
ClientConfig::Ptr config;
TunClientParent& parent;
TunImpl::Ptr impl;
bool halt;
TunProp::State::Ptr state;
};
inline TunClient::Ptr ClientConfig::new_tun_client_obj(openvpn_io::io_context& io_context,
TunClientParent& parent,
TransportClient* transcli)
{
return TunClient::Ptr(new Client(io_context, this, parent));
}
}
}
#endif