working on framework. some trials

.gitignore

@@ -2,3 +2,5 @@
 .vscode
 .vs
 build/
+CMakeSettings.json
+

src/forwarder.hpp

+#ifndef UDP_FORWARDER_DYN_FORWARDER_HPP_
+#define UDP_FORWARDER_DYN_FORWARDER_HPP_
+
+#include <unordered_map>
+#include <rlib/sys/sio.hpp>
+
+#include "utils.hpp"
+using std::string;
+
+struct ConnectionMapping {
+    std::unordered_map<string, fd_t> client2server;
+    std::unordered_multimap<fd_t, string> server2client;
+    static string clientInfoAsKey(string ip, uint16_t port) {
+        // Also works for ipv6. We just want to eliminate duplication, rather than make it easy to read. 
+        return ip + "@" + port;
+    }
+};
+
+class Forwarder {
+public:
+    Forwarder(const std::string& inboundConfig, const std::string& outboundConfig) {
+
+    }
+
+
+private:
+};
+
+#endif

src/lib/picosha2.h

+/*
+The MIT License (MIT)
+
+Copyright (C) 2017 okdshin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+#ifndef PICOSHA2_H
+#define PICOSHA2_H
+// picosha2:20140213
+
+#ifndef PICOSHA2_BUFFER_SIZE_FOR_INPUT_ITERATOR
+#define PICOSHA2_BUFFER_SIZE_FOR_INPUT_ITERATOR \
+    1048576  //=1024*1024: default is 1MB memory
+#endif
+
+#include <algorithm>
+#include <cassert>
+#include <iterator>
+#include <sstream>
+#include <vector>
+#include <fstream>
+namespace picosha2 {
+typedef unsigned long word_t;
+typedef unsigned char byte_t;
+
+static const size_t k_digest_size = 32;
+
+namespace detail {
+inline byte_t mask_8bit(byte_t x) { return x & 0xff; }
+
+inline word_t mask_32bit(word_t x) { return x & 0xffffffff; }
+
+const word_t add_constant[64] = {
+    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
+    0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
+    0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
+    0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
+    0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
+    0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2};
+
+const word_t initial_message_digest[8] = {0x6a09e667, 0xbb67ae85, 0x3c6ef372,
+                                          0xa54ff53a, 0x510e527f, 0x9b05688c,
+                                          0x1f83d9ab, 0x5be0cd19};
+
+inline word_t ch(word_t x, word_t y, word_t z) { return (x & y) ^ ((~x) & z); }
+
+inline word_t maj(word_t x, word_t y, word_t z) {
+    return (x & y) ^ (x & z) ^ (y & z);
+}
+
+inline word_t rotr(word_t x, std::size_t n) {
+    assert(n < 32);
+    return mask_32bit((x >> n) | (x << (32 - n)));
+}
+
+inline word_t bsig0(word_t x) { return rotr(x, 2) ^ rotr(x, 13) ^ rotr(x, 22); }
+
+inline word_t bsig1(word_t x) { return rotr(x, 6) ^ rotr(x, 11) ^ rotr(x, 25); }
+
+inline word_t shr(word_t x, std::size_t n) {
+    assert(n < 32);
+    return x >> n;
+}
+
+inline word_t ssig0(word_t x) { return rotr(x, 7) ^ rotr(x, 18) ^ shr(x, 3); }
+
+inline word_t ssig1(word_t x) { return rotr(x, 17) ^ rotr(x, 19) ^ shr(x, 10); }
+
+template <typename RaIter1, typename RaIter2>
+void hash256_block(RaIter1 message_digest, RaIter2 first, RaIter2 last) {
+    assert(first + 64 == last);
+    static_cast<void>(last);  // for avoiding unused-variable warning
+    word_t w[64];
+    std::fill(w, w + 64, 0);
+    for (std::size_t i = 0; i < 16; ++i) {
+        w[i] = (static_cast<word_t>(mask_8bit(*(first + i * 4))) << 24) |
+               (static_cast<word_t>(mask_8bit(*(first + i * 4 + 1))) << 16) |
+               (static_cast<word_t>(mask_8bit(*(first + i * 4 + 2))) << 8) |
+               (static_cast<word_t>(mask_8bit(*(first + i * 4 + 3))));
+    }
+    for (std::size_t i = 16; i < 64; ++i) {
+        w[i] = mask_32bit(ssig1(w[i - 2]) + w[i - 7] + ssig0(w[i - 15]) +
+                          w[i - 16]);
+    }
+
+    word_t a = *message_digest;
+    word_t b = *(message_digest + 1);
+    word_t c = *(message_digest + 2);
+    word_t d = *(message_digest + 3);
+    word_t e = *(message_digest + 4);
+    word_t f = *(message_digest + 5);
+    word_t g = *(message_digest + 6);
+    word_t h = *(message_digest + 7);
+
+    for (std::size_t i = 0; i < 64; ++i) {
+        word_t temp1 = h + bsig1(e) + ch(e, f, g) + add_constant[i] + w[i];
+        word_t temp2 = bsig0(a) + maj(a, b, c);
+        h = g;
+        g = f;
+        f = e;
+        e = mask_32bit(d + temp1);
+        d = c;
+        c = b;
+        b = a;
+        a = mask_32bit(temp1 + temp2);
+    }
+    *message_digest += a;
+    *(message_digest + 1) += b;
+    *(message_digest + 2) += c;
+    *(message_digest + 3) += d;
+    *(message_digest + 4) += e;
+    *(message_digest + 5) += f;
+    *(message_digest + 6) += g;
+    *(message_digest + 7) += h;
+    for (std::size_t i = 0; i < 8; ++i) {
+        *(message_digest + i) = mask_32bit(*(message_digest + i));
+    }
+}
+
+}  // namespace detail
+
+template <typename InIter>
+void output_hex(InIter first, InIter last, std::ostream& os) {
+    os.setf(std::ios::hex, std::ios::basefield);
+    while (first != last) {
+        os.width(2);
+        os.fill('0');
+        os << static_cast<unsigned int>(*first);
+        ++first;
+    }
+    os.setf(std::ios::dec, std::ios::basefield);
+}
+
+template <typename InIter>
+void bytes_to_hex_string(InIter first, InIter last, std::string& hex_str) {
+    std::ostringstream oss;
+    output_hex(first, last, oss);
+    hex_str.assign(oss.str());
+}
+
+template <typename InContainer>
+void bytes_to_hex_string(const InContainer& bytes, std::string& hex_str) {
+    bytes_to_hex_string(bytes.begin(), bytes.end(), hex_str);
+}
+
+template <typename InIter>
+std::string bytes_to_hex_string(InIter first, InIter last) {
+    std::string hex_str;
+    bytes_to_hex_string(first, last, hex_str);
+    return hex_str;
+}
+
+template <typename InContainer>
+std::string bytes_to_hex_string(const InContainer& bytes) {
+    std::string hex_str;
+    bytes_to_hex_string(bytes, hex_str);
+    return hex_str;
+}
+
+class hash256_one_by_one {
+   public:
+    hash256_one_by_one() { init(); }
+
+    void init() {
+        buffer_.clear();
+        std::fill(data_length_digits_, data_length_digits_ + 4, 0);
+        std::copy(detail::initial_message_digest,
+                  detail::initial_message_digest + 8, h_);
+    }
+
+    template <typename RaIter>
+    void process(RaIter first, RaIter last) {
+        add_to_data_length(static_cast<word_t>(std::distance(first, last)));
+        std::copy(first, last, std::back_inserter(buffer_));
+        std::size_t i = 0;
+        for (; i + 64 <= buffer_.size(); i += 64) {
+            detail::hash256_block(h_, buffer_.begin() + i,
+                                  buffer_.begin() + i + 64);
+        }
+        buffer_.erase(buffer_.begin(), buffer_.begin() + i);
+    }
+
+    void finish() {
+        byte_t temp[64];
+        std::fill(temp, temp + 64, 0);
+        std::size_t remains = buffer_.size();
+        std::copy(buffer_.begin(), buffer_.end(), temp);
+        temp[remains] = 0x80;
+
+        if (remains > 55) {
+            std::fill(temp + remains + 1, temp + 64, 0);
+            detail::hash256_block(h_, temp, temp + 64);
+            std::fill(temp, temp + 64 - 4, 0);
+        } else {
+            std::fill(temp + remains + 1, temp + 64 - 4, 0);
+        }
+
+        write_data_bit_length(&(temp[56]));
+        detail::hash256_block(h_, temp, temp + 64);
+    }
+
+    template <typename OutIter>
+    void get_hash_bytes(OutIter first, OutIter last) const {
+        for (const word_t* iter = h_; iter != h_ + 8; ++iter) {
+            for (std::size_t i = 0; i < 4 && first != last; ++i) {
+                *(first++) = detail::mask_8bit(
+                    static_cast<byte_t>((*iter >> (24 - 8 * i))));
+            }
+        }
+    }
+
+   private:
+    void add_to_data_length(word_t n) {
+        word_t carry = 0;
+        data_length_digits_[0] += n;
+        for (std::size_t i = 0; i < 4; ++i) {
+            data_length_digits_[i] += carry;
+            if (data_length_digits_[i] >= 65536u) {
+                carry = data_length_digits_[i] >> 16;
+                data_length_digits_[i] &= 65535u;
+            } else {
+                break;
+            }
+        }
+    }
+    void write_data_bit_length(byte_t* begin) {
+        word_t data_bit_length_digits[4];
+        std::copy(data_length_digits_, data_length_digits_ + 4,
+                  data_bit_length_digits);
+
+        // convert byte length to bit length (multiply 8 or shift 3 times left)
+        word_t carry = 0;
+        for (std::size_t i = 0; i < 4; ++i) {
+            word_t before_val = data_bit_length_digits[i];
+            data_bit_length_digits[i] <<= 3;
+            data_bit_length_digits[i] |= carry;
+            data_bit_length_digits[i] &= 65535u;
+            carry = (before_val >> (16 - 3)) & 65535u;
+        }
+
+        // write data_bit_length
+        for (int i = 3; i >= 0; --i) {
+            (*begin++) = static_cast<byte_t>(data_bit_length_digits[i] >> 8);
+            (*begin++) = static_cast<byte_t>(data_bit_length_digits[i]);
+        }
+    }
+    std::vector<byte_t> buffer_;
+    word_t data_length_digits_[4];  // as 64bit integer (16bit x 4 integer)
+    word_t h_[8];
+};
+
+inline void get_hash_hex_string(const hash256_one_by_one& hasher,
+                                std::string& hex_str) {
+    byte_t hash[k_digest_size];
+    hasher.get_hash_bytes(hash, hash + k_digest_size);
+    return bytes_to_hex_string(hash, hash + k_digest_size, hex_str);
+}
+
+inline std::string get_hash_hex_string(const hash256_one_by_one& hasher) {
+    std::string hex_str;
+    get_hash_hex_string(hasher, hex_str);
+    return hex_str;
+}
+
+namespace impl {
+template <typename RaIter, typename OutIter>
+void hash256_impl(RaIter first, RaIter last, OutIter first2, OutIter last2, int,
+                  std::random_access_iterator_tag) {
+    hash256_one_by_one hasher;
+    // hasher.init();
+    hasher.process(first, last);
+    hasher.finish();
+    hasher.get_hash_bytes(first2, last2);
+}
+
+template <typename InputIter, typename OutIter>
+void hash256_impl(InputIter first, InputIter last, OutIter first2,
+                  OutIter last2, int buffer_size, std::input_iterator_tag) {
+    std::vector<byte_t> buffer(buffer_size);
+    hash256_one_by_one hasher;
+    // hasher.init();
+    while (first != last) {
+        int size = buffer_size;
+        for (int i = 0; i != buffer_size; ++i, ++first) {
+            if (first == last) {
+                size = i;
+                break;
+            }
+            buffer[i] = *first;
+        }
+        hasher.process(buffer.begin(), buffer.begin() + size);
+    }
+    hasher.finish();
+    hasher.get_hash_bytes(first2, last2);
+}
+}
+
+template <typename InIter, typename OutIter>
+void hash256(InIter first, InIter last, OutIter first2, OutIter last2,
+             int buffer_size = PICOSHA2_BUFFER_SIZE_FOR_INPUT_ITERATOR) {
+    picosha2::impl::hash256_impl(
+        first, last, first2, last2, buffer_size,
+        typename std::iterator_traits<InIter>::iterator_category());
+}
+
+template <typename InIter, typename OutContainer>
+void hash256(InIter first, InIter last, OutContainer& dst) {
+    hash256(first, last, dst.begin(), dst.end());
+}
+
+template <typename InContainer, typename OutIter>
+void hash256(const InContainer& src, OutIter first, OutIter last) {
+    hash256(src.begin(), src.end(), first, last);
+}
+
+template <typename InContainer, typename OutContainer>
+void hash256(const InContainer& src, OutContainer& dst) {
+    hash256(src.begin(), src.end(), dst.begin(), dst.end());
+}
+
+template <typename InIter>
+void hash256_hex_string(InIter first, InIter last, std::string& hex_str) {
+    byte_t hashed[k_digest_size];
+    hash256(first, last, hashed, hashed + k_digest_size);
+    std::ostringstream oss;
+    output_hex(hashed, hashed + k_digest_size, oss);
+    hex_str.assign(oss.str());
+}
+
+template <typename InIter>
+std::string hash256_hex_string(InIter first, InIter last) {
+    std::string hex_str;
+    hash256_hex_string(first, last, hex_str);
+    return hex_str;
+}
+
+inline void hash256_hex_string(const std::string& src, std::string& hex_str) {
+    hash256_hex_string(src.begin(), src.end(), hex_str);
+}
+
+template <typename InContainer>
+void hash256_hex_string(const InContainer& src, std::string& hex_str) {
+    hash256_hex_string(src.begin(), src.end(), hex_str);
+}
+
+template <typename InContainer>
+std::string hash256_hex_string(const InContainer& src) {
+    return hash256_hex_string(src.begin(), src.end());
+}
+template<typename OutIter>void hash256(std::ifstream& f, OutIter first, OutIter last){
+    hash256(std::istreambuf_iterator<char>(f), std::istreambuf_iterator<char>(), first,last);
+
+}
+}// namespace picosha2
+#endif  // PICOSHA2_H

src/lib/wepoll.h

+/*
+ * wepoll - epoll for Windows
+ * https://github.com/piscisaureus/wepoll
+ *
+ * Copyright 2012-2020, Bert Belder <bertbelder@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef WEPOLL_H_
+#define WEPOLL_H_
+
+#ifndef WEPOLL_EXPORT
+#define WEPOLL_EXPORT
+#endif
+
+#include <stdint.h>
+
+enum EPOLL_EVENTS {
+  EPOLLIN      = (int) (1U <<  0),
+  EPOLLPRI     = (int) (1U <<  1),
+  EPOLLOUT     = (int) (1U <<  2),
+  EPOLLERR     = (int) (1U <<  3),
+  EPOLLHUP     = (int) (1U <<  4),
+  EPOLLRDNORM  = (int) (1U <<  6),
+  EPOLLRDBAND  = (int) (1U <<  7),
+  EPOLLWRNORM  = (int) (1U <<  8),
+  EPOLLWRBAND  = (int) (1U <<  9),
+  EPOLLMSG     = (int) (1U << 10), /* Never reported. */
+  EPOLLRDHUP   = (int) (1U << 13),
+  EPOLLONESHOT = (int) (1U << 31)
+};
+
+#define EPOLLIN      (1U <<  0)
+#define EPOLLPRI     (1U <<  1)
+#define EPOLLOUT     (1U <<  2)
+#define EPOLLERR     (1U <<  3)
+#define EPOLLHUP     (1U <<  4)
+#define EPOLLRDNORM  (1U <<  6)
+#define EPOLLRDBAND  (1U <<  7)
+#define EPOLLWRNORM  (1U <<  8)
+#define EPOLLWRBAND  (1U <<  9)
+#define EPOLLMSG     (1U << 10)
+#define EPOLLRDHUP   (1U << 13)
+#define EPOLLONESHOT (1U << 31)
+
+#define EPOLL_CTL_ADD 1
+#define EPOLL_CTL_MOD 2
+#define EPOLL_CTL_DEL 3
+
+typedef void* HANDLE;
+typedef uintptr_t SOCKET;
+
+typedef union epoll_data {
+  void* ptr;
+  int fd;
+  uint32_t u32;
+  uint64_t u64;
+  SOCKET sock; /* Windows specific */
+  HANDLE hnd;  /* Windows specific */
+} epoll_data_t;
+
+struct epoll_event {
+  uint32_t events;   /* Epoll events and flags */
+  epoll_data_t data; /* User data variable */
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+WEPOLL_EXPORT HANDLE epoll_create(int size);
+WEPOLL_EXPORT HANDLE epoll_create1(int flags);
+
+WEPOLL_EXPORT int epoll_close(HANDLE ephnd);
+
+WEPOLL_EXPORT int epoll_ctl(HANDLE ephnd,
+                            int op,
+                            SOCKET sock,
+                            struct epoll_event* event);
+
+WEPOLL_EXPORT int epoll_wait(HANDLE ephnd,
+                             struct epoll_event* events,
+                             int maxevents,
+                             int timeout);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* WEPOLL_H_ */

src/protocols/base.hpp

+#ifndef UDP_FORWARDER_PROT_BASE_HPP_
+#define UDP_FORWARDER_PROT_BASE_HPP_ 1
+
+#include <rlib/class_decorator.hpp>
+#include <string>
+using std::string;
+
+namespace Protocols {
+	class BaseHandler : rlib::noncopyable {
+		BaseHandler(string outboundConfig) {
+			loadConfig(outboundConfig);
+		}
+		virtual ~BaseOutboundHandler = default;
+
+		// Interfaces
+		virtual loadConfig(string config) = 0;
+		virtual handleMessage(string binaryMessage) = 0;
+	};
+
+	class BaseListener : rlib::noncopyable {
+		BaseListener(string inboundConfig) {
+			loadConfig(inboundConfig);
+		}
+		virtual loadConfig(string config) = 0;
+		virtual listenForever(BaseHandler *nextHop) = 0;
+	};
+}
+
+#endif
+
+
+

src/protocols/misc.hpp

+#ifndef UDP_FORWARDER_PROT_PLAIN_HPP_
+#define UDP_FORWARDER_PROT_PLAIN_HPP_ 1
+
+#include <protocols/base.hpp>
+#include <rlib/sys/sio.hpp>
+#include <rlib/string.hpp>
+
+namespace Protocols {
+	class MiscInboundListener : public BaseListener {
+	public:
+		virtual loadConfig(string config) override {
+			auto ar = rlib::string(config).split('@'); // Also works for ipv6.
+			if (ar.size() != 4)
+				throw std::invalid_argument("Wrong parameter string for protocol 'misc'. Example:    plain@fe00:1e10:ce95:1@1080-3080@MyPassword");
+			listenAddr = ar[1];
+			// listenPort = ar[2].as<uint16_t>();
+			psk = ar[3];
+
+
+		}
+		virtual listenForever(BaseHandler* nextHop) override {
+
+		}
+
+	private:
+		string listenAddr;
+		uint16_t listenPort;
+		string psk;
+	};
+
+	class MiscOutboundListener : public BaseListener {
+
+	};
+
+	class MiscOutboundHandler : public BaseHandler {
+
+	};
+}
+
+#endif
+
+

src/protocols/plain.hpp

+#ifndef UDP_FORWARDER_PROT_PLAIN_HPP_
+#define UDP_FORWARDER_PROT_PLAIN_HPP_ 1
+
+#include <protocols/base.hpp>
+#include <rlib/sys/sio.hpp>
+#include <rlib/string.hpp>
+
+namespace Protocols {
+	class PlainInboundListener : public BaseListener {
+	public:
+		virtual loadConfig(string config) override {
+			auto ar = rlib::string(config).split('@'); // Also works for ipv6.
+			if (ar.size() != 3)
+				throw std::invalid_argument("Wrong parameter string for protocol 'plain'. Example:    plain@fe00:1e10:ce95:1@10809");
+			auto listenAddr = ar[1];
+			auto listenPort = ar[2].as<uint16_t>();
+
+			listenFd = rlib::quick_listen(listenAddr, listenPort, true);
+		}
+		virtual listenForever(BaseHandler* nextHop) override {
+
+		}
+
+	private:
+		fd_t listenFd;
+	};
+
+	using PlainOutboundListener = PlainInboundListener;
+
+	class PlainOutboundHandler {
+
+	};
+}
+
+#endif
+
+
+

src/utils.hpp

+#ifndef UDP_FORWARDER_DYN_UTILs_HPP_
+#define UDP_FORWARDER_DYN_UTILs_HPP_ 1
+
+#include <rlib/sys/os.hpp>
+
+#if RLIB_OS_ID == OS_LINUX
+#include <sys/epoll.h>
+#elif RLIB_OS_ID == OS_WINDOWS
+#include <wepoll.h>
+#endif
+
+inline void epoll_add_fd(fd_t epollFd, fd_t fd) {
+    epoll_event event {
+        .events = EPOLLIN,
+        .data = {
+                .fd = fd,
+        }
+    };
+    auto ret1 = epoll_ctl(epollFd, EPOLL_CTL_ADD, fd, &event);
+    if(ret1 == -1)
+        throw std::runtime_error("epoll_ctl failed.");
+}
+inline void epoll_del_fd(fd_t epollFd, fd_t fd) {
+    epoll_event event {
+        .events = EPOLLIN,
+        .data = {
+                .fd = fd,
+        }
+    };
+    auto ret1 = epoll_ctl(epollFd, EPOLL_CTL_DEL, fd, &event); // Can be nullptr since linux 2.6.9
+    if(ret1 == -1)
+        throw std::runtime_error("epoll_ctl failed.");
+}
+
+
+
+#endif
+