what have i done?

include/insane_dns/constants.h

@@ -1,6 +1,6 @@
 /*
  *  Global constants file.
- *  Copyright (C) 2023  Brett Terpstra
+ *  Copyright (C) 2023  Brett Terpstra, Et al
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -24,7 +24,35 @@
  *          | Magic Number Constants |
  * --------------------------------------------
  */
-/** DNS header data offset. This is the first byte that isn't a header value (should be question label length octet) */
+
-static constexpr size_t DNS_HEADER_END = 12;
+static constexpr size_t PACKET_BUFFER_SIZE = 65535;
+
+/*
+ * These structs are used in combination with templates to create a form of polymorphism which has significantly reduced the code reuse.
+ * The data set within these structures are specific to the protocol they implement. UDP is exactly as specified in the RFC spec
+ * TCP is what I observed from wireshark (+2 byte offset)
+ */
+struct DNS_UDP_INFO_t
+{
+    /** DNS header data offset. This is the first byte that isn't a header value (should be question label length octet) */
+    size_t HEADER_END = 12;
+    /** DNS questions count data offset. In the standard header this is 4 bytes in */
+    size_t QUESTIONS_BEGIN = 4;
+    /** DNS answer count data offset. */
+    size_t ANSWERS_BEGIN = 6;
+};
+
+/*
+ * The TCP version appears to use a 2 byte unsigned short to represent length. This struct accounts for that.
+ */
+struct DNS_TCP_INFO_t
+{
+    size_t HEADER_END = 14;
+    size_t QUESTIONS_BEGIN = 6;
+    size_t ANSWERS_BEGIN = 8;
+};
+
+static constexpr DNS_UDP_INFO_t DNS_UDP_INFO;
+static constexpr DNS_TCP_INFO_t DNS_TCP_INFO;
 
 #endif //INSANE_DNS_CONSTANTS_H

include/insane_dns/util.h

@@ -1,7 +1,7 @@
 /*
- *  BLT Memory Util for parsing DNS packets.
+ *  BLT Memory Util for parsing DNS packets / BLT + ASIO simple packet sender.
  *  This software is unlikely to become part of BLT main but is provided under the BLT license (GPL 3).
- *  Copyright (C) 2023  Brett Terpstra
+ *  Copyright (C) 2023  Brett Terpstra, Et al
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -21,6 +21,14 @@
 #define INSANE_DNS_UTIL_H
 
 #include <insane_dns/constants.h>
+#include <type_traits>
+#include <asio.hpp>
+#include <cstdint>
+#include <functional>
+#include <blt/std/memory.h>
+
+using asio::ip::udp;
+using asio::ip::tcp;
 
 namespace blt
 {
@@ -28,20 +36,17 @@ namespace blt
     /**
      * Basic parser for processing strings of bytes received from UDP sockets. This class provides a simple interface for efficiently copying the
      * big endian bytes from the network into the little endian bytes required by x86 processors. The class also provides basic safety guarantees
-     * in that the program will halt execution if reading the bytes would overflow the internal buffer.
+     * in the sense that the program will halt execution if reading the bytes would overflow the internal buffer.
      */
     class byte_reader
     {
         private:
             unsigned char* _data;
             const size_t _size;
-            mutable size_t _current_byte = DNS_HEADER_END;
+            mutable size_t _current_byte;
         public:
-            explicit byte_reader(unsigned char* data, size_t size, bool tcp = false): _data(data), _size(size)
+            explicit byte_reader(unsigned char* data, size_t size, size_t start_offset): _data(data), _size(size), _current_byte(start_offset)
-            {
+            {}
-                if (tcp)
-                    _current_byte += 2;
-            }
             
             /**
              * Read the next byte in the data stream then increment the internal counter by 1
@@ -109,7 +114,71 @@ namespace blt
                 return &_data[_current_byte];
             }
     };
-
+    
+    namespace network
+    {
+        /**
+         * Sends a simple UDP message to the provided host on the DNS port and outputs the response into the out buffer
+         * @param host host to send the message to
+         * @param in buffer to send
+         * @param in_size size of buffer
+         * @param out buffer to write to
+         * @param out_size size of data that was written. Make sure `out` has enough room for the packet.
+         */
+        void sendUDPMessage(const std::string& host, const unsigned char*& in, size_t in_size, blt::scoped_buffer<unsigned char>& out,
+                            size_t& out_size)
+        {
+            asio::io_context io_context;
+            udp::endpoint receiver_endpoint(asio::ip::address::from_string(host), 53);
+            
+            udp::socket socket(io_context);
+            socket.open(udp::v4());
+            
+            socket.send_to(asio::const_buffers_1(in, in_size), receiver_endpoint);
+            
+            udp::endpoint sender_endpoint;
+            out_size = socket.receive_from(asio::buffer(out.data(), out.size()), sender_endpoint);
+        }
+        
+        /**
+         * Sends a simple TCP message to the provided host on the DNS port and outputs the response into the out buffer
+         * @param host host to send the message to
+         * @param in buffer to send
+         * @param in_size size of buffer
+         * @param out buffer to write to
+         * @param out_size size of data that was written. Make sure `out` has enough room for the packet.
+         */
+        void sendTCPMessage(const std::string& host, const unsigned char*& in, size_t in_size, blt::scoped_buffer<unsigned char>& out,
+                            size_t& out_size)
+        {
+            asio::io_context io_context;
+            tcp::resolver resolver(io_context);
+            tcp::resolver::results_type endpoints = resolver.resolve(host, "53");
+            
+            tcp::socket socket(io_context);
+            asio::connect(socket, endpoints);
+            
+            asio::write(socket, asio::buffer(in, in_size));
+            
+            out_size = socket.read_some(asio::buffer(out.data(), out.size()));
+        }
+    }
+    
 }
 
 #endif //INSANE_DNS_UTIL_H
+
+// these are no longer used, but I am keeping them around because they are useful and were not added to git
+
+//    template<class T>
+//    struct is_byte_ptr_type : std::integral_constant<bool,
+//            std::is_same_v<T, std::int8_t*> || std::is_same_v<T, std::uint8_t*> ||
+//            std::is_same_v<T, unsigned char*> || std::is_same_v<T, char*> || std::is_same_v<T, signed char*>>
+//    {
+//    };
+//
+//    template<typename T>
+//    inline constexpr bool is_byte_ptr_type_v = is_byte_ptr_type<T>::value;
+//
+//    template<typename IN, typename OUT>
+//    using messageFunction = std::function<void(const std::string&, const IN&, size_t, OUT&, size_t&)>;

libraries/BLT

@@ -1 +1 @@
-Subproject commit 16ba4ed192f877d1ea6c9e81c22cb2b04b2014f5
+Subproject commit 55c497475e15b9a4ff0ac319c2997bd1869c4454

src/ip.h

@@ -6,11 +6,10 @@
 #define INSANE_DNS_IP_H
 
 #include <blt/std/string.h>
+#include <blt/compatibility.h>
 #include <blt/std/assert.h>
-#include <asio.hpp>
 
-using asio::ip::udp;
+#include <asio.hpp>
-using asio::ip::tcp;
 
 struct IPAddress
 {
@@ -34,33 +33,68 @@ struct IPAddress
     }
 };
 
-template<typename IN, typename OUT>
+struct bind_address
-void sendUDPMessage(const std::string& host, const IN& in, size_t in_size, OUT& out, size_t& out_size)
 {
-    asio::io_context io_context;
+    unsigned short int port;
-    udp::endpoint receiver_endpoint(asio::ip::address::from_string(host), 53);
+    bool use_v4 = true;
-    
+    bool use_v6 = true;
-    udp::socket socket(io_context);
+    // if these are empty it will use ASIO default
-    socket.open(udp::v4());
+    std::string IP_V4;
-    
+    std::string IP_V6;
-    socket.send_to(asio::const_buffers_1(in, in_size), receiver_endpoint);
+};
-    
+
-    udp::endpoint sender_endpoint;
+// using a template instead of a macro. Are you proud of me dad?
-    out_size = socket.receive_from(asio::buffer(out), sender_endpoint);
+template<typename RET, typename V4, typename V6>
+inline RET BLT_INTERNAL_ENDPOINT(const bind_address& address, V4 v4, V6 v6)
+{
+    // this is an ugly mess. Ignore it.
+    BLT_ASSERT(address.use_v4 || address.use_v6);
+    if (address.use_v6)
+    {
+        if (address.IP_V6.empty())
+            return {v6, address.port};
+        else
+            return {asio::ip::address::from_string(address.IP_V6), address.port};
+    }
+    if (address.use_v4)
+    {
+        if (address.IP_V4.empty())
+            return {v4, address.port};
+        else
+            return {asio::ip::address::from_string(address.IP_V4), address.port};
+    }
+    // suppress compiler warnings. Also, could do std::exit() but this is more fun :3
+    return {asio::ip::address::from_string("Unreachable Code"), 42069};
 }
 
-template<typename IN, typename OUT>
+/**
-void sendTCPMessage(const std::string& host, const IN& in, size_t in_size, OUT& out, size_t& out_size){
+ * Convert a bind_address into a ASIO UDP endpoint
-    asio::io_context io_context;
+ * @param address address to convert
-    tcp::resolver resolver(io_context);
+ * @return ASIO UDP endpoint
-    tcp::resolver::results_type endpoints = resolver.resolve(host, "53");
+ */
-    
+inline asio::ip::udp::endpoint toUDPEndpoint(const bind_address& address)
-    tcp::socket socket(io_context);
+{
-    asio::connect(socket, endpoints);
+    auto v4 = asio::ip::udp::v4();
-    
+    auto v6 = asio::ip::udp::v6();
-    asio::write(socket, asio::buffer(in, in_size));
+    return BLT_INTERNAL_ENDPOINT<asio::ip::udp::endpoint>(address, v4, v6);
-    
-    out_size = socket.read_some(asio::buffer(out));
 }
 
+/**
+ * Convert a bind_address into a ASIO TCP endpoint
+ * @param address address to convert
+ * @return ASIO TCP endpoint
+ */
+inline asio::ip::tcp::endpoint toTCPEndpoint(const bind_address& address)
+{
+    auto v4 = asio::ip::tcp::v4();
+    auto v6 = asio::ip::tcp::v6();
+    return BLT_INTERNAL_ENDPOINT<asio::ip::tcp::endpoint>(address, v4, v6);
+}
+
+struct request_info
+{
+    size_t number_of_bytes;
+    size_t number_of_answers;
+};
+
 #endif //INSANE_DNS_IP_H

src/main.cpp

@@ -28,6 +28,12 @@
 /** What port to run the server on */
 static constexpr unsigned short int SERVER_PORT = 5555;
 
+/**
+ * How should we bind to the local machine? By default this will use IPv4 and IPv6 with the default ASIO endpoint.
+ * Only change this if you really need to and know what you are doing.
+ */
+static constexpr bind_address address{SERVER_PORT};
+
 /** should we strictly match results? ie block `*wikipedia.org*` or just `wikipedia.org`? */
 static constexpr bool STRICT_MATCHING = false;
 
@@ -60,13 +66,14 @@ static const std::unordered_set<std::string> DISALLOWED_DOMAINS{
  */
 // these features were planned but not added because I realized you guys won't care or give extra marks which broke my obsession with it
 // so uhh don't change em otherwise the code will break :3
+// as it is im still adding new features and stuff (TCP) and messing with the code trying to get it cleaner
 
 /** true -> only match A records ; false -> match any named record (configure with NON_STRICT_REPLACE_ALL) */
 static constexpr bool STRICT_FILTERING = true;
 /** true -> match all records ; false -> match only records we might want to replace (A, AAAA, CNAME) */
 static constexpr bool NON_STRICT_REPLACE_ALL = true;
 
-// was going to add TCP and ad blocking support
+// was going to add ~~TCP~~ (this is now a thing for full DIG support. "can you dig it, sucka!?") and ad blocking support
 // that also isn't going to happen now.
 /** list of web address to download the ad block lists from */
 static BLT_CPP20_CONSTEXPR std::vector<std::string> BLOCK_LISTS{};
@@ -107,8 +114,8 @@ class question
         friend send_buffer;
     private:
         std::string domain;
-        uint16_t QTYPE;
+        uint16_t QTYPE = 0;
-        uint16_t QCLASS;
+        uint16_t QCLASS = 0;
     public:
         explicit question(const blt::byte_reader& reader)
         {
@@ -327,75 +334,89 @@ void process_answers(std::vector<answer>& answers)
     }
 }
 
+template<typename T, typename INFO, typename MESSENGER>
+request_info handle_forward_request(MESSENGER messenger, const INFO& info, const T& input_recv_buffer, size_t bytes, T& forward_recv_buffer)
+{
+    // get the number of questions
+    uint16_t questions; // yes I made this part of my library just for this :3
+    blt::mem::fromBytes(&input_recv_buffer[info.QUESTIONS_BEGIN], questions); // i hate little endian
+    
+    BLT_INFO("Bytes received: %d with %d questions", bytes, questions);
+    
+    // forward to google.
+    size_t out_bytes;
+    auto data = input_recv_buffer.data();
+    messenger(DNS_SERVER_IP(), data, bytes, forward_recv_buffer, out_bytes);
+    
+    uint16_t num_of_answers;
+    blt::mem::fromBytes(&forward_recv_buffer[info.ANSWERS_BEGIN], num_of_answers);
+    
+    return {out_bytes, num_of_answers};
+}
+
+template<typename T, typename INFO>
+void handle_response(const INFO& info, send_buffer& return_send_buffer, request_info rq_info, T& forward_recv_buffer)
+{
+    blt::byte_reader reader(forward_recv_buffer.data(), forward_recv_buffer.size(), info.HEADER_END);
+    
+    BLT_INFO("Bytes answered: %d with %d answers", rq_info.number_of_bytes, rq_info.number_of_answers);
+    
+    // no one actually does multiple questions. trying to do it in dig is not easy
+    // and the standard isn't really designed for this (how do we handle if one question errors but the other doesn't? there is only
+    // one return code.)
+    question q(reader);
+    std::vector<answer> answers;
+    for (size_t i = 0; i < rq_info.number_of_answers; i++)
+    {
+        answer a(reader);
+        answers.push_back(std::move(a));
+    }
+    
+    BLT_INFO("DOMAIN: %s", q().c_str());
+    if (STRICT_MATCHING && BLT_CONTAINS(DISALLOWED_DOMAINS, q()))
+        process_answers(answers);
+    else if (!STRICT_MATCHING)
+    {
+        // linear search the domains for contains. Maybe find a better way to do this.
+        for (const auto& v : DISALLOWED_DOMAINS)
+            if (blt::string::contains(q(), v))
+                process_answers(answers);
+    }
+    
+    return_send_buffer.write(forward_recv_buffer.data(), info.HEADER_END);
+    auto question_offset = return_send_buffer.size();
+    return_send_buffer.write(q);
+    for (const answer& a : answers)
+    {
+        BLT_TRACE("Writing answer with type of %d", a.type());
+        a.reset(question_offset);
+        return_send_buffer.write(a);
+    }
+    return_send_buffer.write(reader.from(), rq_info.number_of_bytes - reader.last());
+}
+
 void run_udp_server()
 {
     try
     {
         asio::io_context io_context;
         
-        //udp::socket socket(io_context, udp::endpoint(udp::v6(), 5555));
+        udp::socket socket(io_context, toUDPEndpoint(address));
-        udp::socket socket(io_context, udp::endpoint(asio::ip::address::from_string("::1"), SERVER_PORT));
         
-        std::array<unsigned char, 65535> recv_buf{};
+        blt::scoped_buffer<unsigned char> input_recv_buffer{PACKET_BUFFER_SIZE};
-        std::array<unsigned char, 65535> mod_recv_buf{};
+        blt::scoped_buffer<unsigned char> forward_recv_buffer{PACKET_BUFFER_SIZE};
         while (true)
         {
             udp::endpoint remote_endpoint;
-            size_t bytes = socket.receive_from(asio::buffer(recv_buf), remote_endpoint);
+            size_t bytes = socket.receive_from(asio::buffer(input_recv_buffer.data(), input_recv_buffer.size()), remote_endpoint);
             
-            // get the number of questions
+            auto rq_info = handle_forward_request(blt::network::sendUDPMessage, DNS_UDP_INFO, input_recv_buffer, bytes, forward_recv_buffer);
-            uint16_t questions; // yes I made this part of my library just for this :3
-            blt::mem::fromBytes(&recv_buf[4], questions); // i hate little endian
             
-            BLT_INFO("Bytes received: %d with %d questions", bytes, questions);
+            send_buffer return_send_buffer;
-            
+            handle_response(DNS_UDP_INFO, return_send_buffer, rq_info, forward_recv_buffer);
-            // forward to google.
-            size_t out_bytes;
-            sendUDPMessage(DNS_SERVER_IP(), recv_buf.data(), bytes, mod_recv_buf, out_bytes);
-            
-            uint16_t num_of_answers;
-            blt::mem::fromBytes(&mod_recv_buf[6], num_of_answers);
-            
-            blt::byte_reader reader(mod_recv_buf.data(), mod_recv_buf.size());
-            
-            BLT_INFO("Bytes answered: %d with %d answers", out_bytes, num_of_answers);
-            
-            // no one actually does multiple questions. trying to do it in dig is not easy
-            // and the standard isn't really designed for this (how do we handle if one question errors but the other doesn't? there is only
-            // one return code.)
-            question q(reader);
-            std::vector<answer> answers;
-            for (int i = 0; i < num_of_answers; i++)
-            {
-                answer a(reader);
-                answers.push_back(std::move(a));
-            }
-            
-            BLT_INFO("DOMAIN: %s", q().c_str());
-            if (STRICT_MATCHING && BLT_CONTAINS(DISALLOWED_DOMAINS, q()))
-                process_answers(answers);
-            else if (!STRICT_MATCHING)
-            {
-                // linear search the domains for contains. Maybe find a better way to do this.
-                for (const auto& v : DISALLOWED_DOMAINS)
-                    if (blt::string::contains(q(), v))
-                        process_answers(answers);
-            }
-            
-            send_buffer send;
-            send.write(mod_recv_buf.data(), 12);
-            auto question_offset = send.size();
-            send.write(q);
-            for (const answer& a : answers)
-            {
-                BLT_TRACE("Writing answer with type of %d", a.type());
-                a.reset(question_offset);
-                send.write(a);
-            }
-            send.write(reader.from(), out_bytes - reader.last());
             
             asio::error_code ignored_error;
-            socket.send_to(send.buffer(), remote_endpoint, 0, ignored_error);
+            socket.send_to(return_send_buffer.buffer(), remote_endpoint, 0, ignored_error);
         }
     }
     catch (std::exception& e)
@@ -410,74 +431,28 @@ void run_tcp_server()
     {
         asio::io_context io_context;
         
-        tcp::acceptor acceptor(io_context, tcp::endpoint(asio::ip::address::from_string("::1"), SERVER_PORT));
+        tcp::acceptor acceptor(io_context, toTCPEndpoint(address));
         
-        std::array<unsigned char, 65535> recv_buf{};
+        blt::scoped_buffer<unsigned char> input_recv_buffer{PACKET_BUFFER_SIZE};
-        std::array<unsigned char, 65535> mod_recv_buf{};
+        blt::scoped_buffer<unsigned char> forward_recv_buffer{PACKET_BUFFER_SIZE};
         while (true)
         {
             tcp::socket socket(io_context);
             acceptor.accept(socket);
             
             asio::error_code error;
-            size_t bytes = socket.read_some(asio::buffer(recv_buf), error);
+            size_t bytes = socket.read_some(asio::buffer(input_recv_buffer.data(), input_recv_buffer.size()), error);
             if (error == asio::error::eof)
                 break;
             else if (error)
                 throw asio::system_error(error);
             
-            // get the number of questions
+            auto rq_info = handle_forward_request(blt::network::sendTCPMessage, DNS_TCP_INFO, input_recv_buffer, bytes, forward_recv_buffer);
-            uint16_t questions; // yes I made this part of my library just for this :3
-            blt::mem::fromBytes(&recv_buf[6], questions); // i hate little endian
             
-            BLT_INFO("TCP Bytes received: %d with %d questions", bytes, questions);
+            send_buffer return_send_buffer;
+            handle_response(DNS_TCP_INFO, return_send_buffer, rq_info, forward_recv_buffer);
             
-            // forward to google.
+            asio::write(socket, return_send_buffer.buffer());
-            size_t out_bytes;
-            sendTCPMessage(DNS_SERVER_IP(), recv_buf.data(), bytes, mod_recv_buf, out_bytes);
-            
-            uint16_t num_of_answers;
-            blt::mem::fromBytes(&mod_recv_buf[8], num_of_answers);
-            
-            blt::byte_reader reader(mod_recv_buf.data(), mod_recv_buf.size(), true);
-            
-            BLT_INFO("TCP Bytes answered: %d with %d answers", out_bytes, num_of_answers);
-            
-            // no one actually does multiple questions. trying to do it in dig is not easy
-            // and the standard isn't really designed for this (how do we handle if one question errors but the other doesn't? there is only
-            // one return code.)
-            question q(reader);
-            std::vector<answer> answers;
-            for (int i = 0; i < num_of_answers; i++)
-            {
-                answer a(reader);
-                answers.push_back(std::move(a));
-            }
-            
-            BLT_INFO("TCP DOMAIN: %s", q().c_str());
-            if (STRICT_MATCHING && BLT_CONTAINS(DISALLOWED_DOMAINS, q()))
-                process_answers(answers);
-            else if (!STRICT_MATCHING)
-            {
-                // linear search the domains for contains. Maybe find a better way to do this.
-                for (const auto& v : DISALLOWED_DOMAINS)
-                    if (blt::string::contains(q(), v))
-                        process_answers(answers);
-            }
-            
-            send_buffer send;
-            send.write(mod_recv_buf.data(), 12);
-            auto question_offset = send.size();
-            send.write(q);
-            for (const answer& a : answers)
-            {
-                BLT_TRACE("TCP Writing answer with type of %d", a.type());
-                a.reset(question_offset);
-                send.write(a);
-            }
-            send.write(reader.from(), out_bytes - reader.last());
-            
-            asio::write(socket, send.buffer());
         }
     }
     catch (std::exception& e)