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/*
* Copyright (c) 2020 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <hicn/transport/portability/c_portability.h>
#include <hicn/transport/utils/branch_prediction.h>
#include <hicn/transport/utils/log.h>
#include <hicn/transport/utils/string_utils.h>
#include <asio.hpp>
#include <chrono>
#include <sstream>
#include <string>
#include "forwarder_interface.h"
#define RETRY_INTERVAL 300
namespace transport {
static constexpr char server_header[] = "server";
static constexpr char prefix_header[] = "prefix";
static constexpr char port_header[] = "port";
using OnForwarderConfiguredCallback = std::function<void(bool)>;
class ForwarderConfig {
public:
using ListenerRetrievedCallback = std::function<void(std::error_code)>;
template <typename Callback>
ForwarderConfig(asio::io_service& io_service, Callback&& callback)
: forwarder_interface_(io_service),
resolver_(io_service),
retx_count_(0),
timer_(io_service),
hicn_listen_port_(~0),
listener_retrieved_callback_(std::forward<Callback>(callback)) {}
void close() {
timer_.cancel();
resolver_.cancel();
forwarder_interface_.close();
}
void tryToConnectToForwarder() {
doTryToConnectToForwarder(std::make_error_code(std::errc(0)));
}
void doTryToConnectToForwarder(std::error_code ec) {
if (!ec) {
// ec == 0 --> timer expired
int ret = forwarder_interface_.connectToForwarder();
if (ret < 0) {
// We were not able to connect to the local forwarder. Do not give up
// and retry.
TRANSPORT_LOG_ERROR
<< "Could not connect to local forwarder. Retrying.";
timer_.expires_from_now(std::chrono::milliseconds(RETRY_INTERVAL));
timer_.async_wait(std::bind(&ForwarderConfig::doTryToConnectToForwarder,
this, std::placeholders::_1));
} else {
timer_.cancel();
retx_count_ = 0;
doGetMainListener(std::make_error_code(std::errc(0)));
}
} else {
TRANSPORT_LOG_ERROR
<< "Timer for re-trying forwarder connection canceled.";
}
}
void doGetMainListener(std::error_code ec) {
if (!ec) {
// ec == 0 --> timer expired
int ret = forwarder_interface_.getMainListenerPort();
if (ret <= 0) {
// Since without the main listener of the forwarder the proxy cannot
// work, we can stop the program here until we get the listener port.
TRANSPORT_LOG_ERROR
<< "Could not retrieve main listener port from the forwarder. "
"Retrying.";
timer_.expires_from_now(std::chrono::milliseconds(RETRY_INTERVAL));
timer_.async_wait(std::bind(&ForwarderConfig::doGetMainListener, this,
std::placeholders::_1));
} else {
timer_.cancel();
retx_count_ = 0;
hicn_listen_port_ = uint16_t(ret);
listener_retrieved_callback_(std::make_error_code(std::errc(0)));
}
} else {
TRANSPORT_LOG_ERROR
<< "Timer for retrieving main hicn listener canceled.";
}
}
template <typename Callback>
TRANSPORT_ALWAYS_INLINE bool parseHicnHeader(std::string& header,
Callback&& callback) {
std::stringstream ss(header);
route_info_t* ret = new route_info_t();
std::string port_string;
while (ss.good()) {
std::string substr;
getline(ss, substr, ',');
if (TRANSPORT_EXPECT_FALSE(substr.empty())) {
continue;
}
utils::trim(substr);
auto it = std::find_if(substr.begin(), substr.end(),
[](int ch) { return ch == '='; });
if (it != std::end(substr)) {
auto key = std::string(substr.begin(), it);
auto value = std::string(it + 1, substr.end());
if (key == server_header) {
ret->remote_addr = value;
} else if (key == prefix_header) {
auto it = std::find_if(value.begin(), value.end(),
[](int ch) { return ch == '/'; });
if (it != std::end(value)) {
ret->route_addr = std::string(value.begin(), it);
ret->route_len = std::stoul(std::string(it + 1, value.end()));
} else {
return false;
}
} else if (key == port_header) {
ret->remote_port = std::stoul(value);
port_string = value;
} else {
// Header not recognized
return false;
}
}
}
/*
* Resolve server address
*/
auto results =
resolver_.resolve({ret->remote_addr, port_string,
asio::ip::resolver_query_base::numeric_service});
#if ((ASIO_VERSION / 100 % 1000) < 12)
asio::ip::udp::resolver::iterator end;
auto& it = results;
while (it != end) {
#else
for (auto it = results.begin(); it != results.end(); it++) {
#endif
if (it->endpoint().address().is_v4()) {
// Use this v4 address to configure the forwarder.
ret->remote_addr = it->endpoint().address().to_string();
ret->family = AF_INET;
std::string _prefix = ret->route_addr;
forwarder_interface_.createFaceAndRoute(
RouteInfoPtr(ret), [callback = std::forward<Callback>(callback),
configured_prefix = std::move(_prefix)](
uint32_t route_id, bool result) {
callback(result, configured_prefix);
});
return true;
}
#if ((ASIO_VERSION / 100 % 1000) < 12)
it++;
#endif
}
return false;
}
private:
ForwarderInterface forwarder_interface_;
asio::ip::udp::resolver resolver_;
std::uint32_t retx_count_;
asio::steady_timer timer_;
uint16_t hicn_listen_port_;
ListenerRetrievedCallback listener_retrieved_callback_;
}; // namespace transport
} // namespace transport
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