dns

cmake-build-debug/.ninja_log

@@ -33,3 +33,29 @@
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cmake-build-debug/Testing/Temporary/LastTest.log

@@ -1,3 +1,3 @@
-Start testing: Oct 25 16:56 EDT
+Start testing: Oct 25 21:44 EDT
 ----------------------------------------------------------
-End testing: Oct 25 16:56 EDT
+End testing: Oct 25 21:44 EDT

src/ip.h

@@ -15,16 +15,15 @@ using asio::ip::tcp;
 struct IPAddress
 {
     unsigned char octets[4];
+    std::string asString;
     
-    constexpr IPAddress(const std::string& str)
+    constexpr IPAddress(std::string str)
     {
         auto data = blt::string::split(str, '.');
         BLT_ASSERT(data.size() == 4);
         for (size_t i = 0; i < data.size(); i++)
-        {
             octets[i] = static_cast<unsigned char>(std::stoul(data[i]));
-            BLT_TRACE("%d", octets[i]);
+        asString = std::move(str);
-        }
     }
     
     constexpr IPAddress(unsigned char oct[4])

src/main.cpp

@@ -25,8 +25,10 @@
  */
 // should we strictly match results? ie block *wikipedia.org* or just wikipedia.org?
 static constexpr bool STRICT_MATCHING = false;
-// true -> only match A records ; false -> match any named record (A, AAAA, CNAME)
+// true -> only match A records ; false -> match any named record (configure with NON_STRICT_REPLACE_ALL)
 static constexpr bool STRICT_FILTERING = false;
+// true -> match all records ; false -> match only records we might want to replace (A, AAAA, CNAME)
+static constexpr bool NON_STRICT_REPLACE_ALL = true;
 
 // DNS server to use for forwarding to / resolving DNS requests
 static inline constexpr std::string DNS_SERVER_IP()
@@ -42,6 +44,7 @@ static inline constexpr IPAddress REPLACEMENT_IP()
 
 static const std::unordered_set<std::string> DISALLOWED_DOMAINS{
         "en.wikipedia.org",
+        "tpgc.me",
         "zombo.com"
 };
 
@@ -158,11 +161,12 @@ class answer
 {
         friend send_buffer;
     private:
-        uint16_t NAME = 0;
+        mutable uint16_t NAME = 0;
         uint16_t TYPE = 0;
         uint16_t CLASS = 0;
         uint32_t TTL = 0;
         uint16_t RDLENGTH = 0;
+        bool requires_reset = false;
         unsigned char* RDATA = nullptr;
     public:
         explicit answer(const byte_reader& reader)
@@ -183,12 +187,34 @@ class answer
             return TYPE;
         }
         
-        void substitute(const IPAddress& addr)
+        inline void substitute(const IPAddress& addr)
         {
+            BLT_DEBUG("Substituting with replacement address '%s'", REPLACEMENT_IP().asString.c_str());
             BLT_ASSERT(RDLENGTH == 4);
             std::memcpy(RDATA, addr.octets, 4);
         }
         
+        inline void setARecord(const IPAddress& addr)
+        {
+            BLT_DEBUG("Setting to A record");
+            NAME = 0;
+            NAME |= (0b11 << 14);
+            requires_reset = true;
+            BLT_INFO(NAME);
+            delete[] RDATA;
+            RDATA = new unsigned char[4];
+            RDLENGTH = 4;
+            TYPE = 1;
+            CLASS = 1;
+            substitute(addr);
+        }
+        
+        inline void reset(size_t offset) const
+        {
+            auto i16 = static_cast<uint16_t>(offset) & (~(0b11 << 14));
+            NAME |= i16;
+        }
+        
         // rule of 5
         answer(const answer& answer) = delete;
         
@@ -207,6 +233,7 @@ class answer
         
         answer& operator=(answer&& move)
         {
+            NAME = 0;
             NAME = move.NAME;
             TYPE = move.TYPE;
             CLASS = move.CLASS;
@@ -233,7 +260,6 @@ class send_buffer
         
         void write(unsigned char* data, size_t size) const
         {
-            BLT_TRACE(size);
             std::memcpy(&internal_data[write_index], data, size);
             write_index += size;
         }
@@ -301,17 +327,24 @@ class send_buffer
         }
 };
 
-bool shouldReplace(const answer& a)
+inline bool shouldReplace(const answer& a)
 {
-    return a.type() == 1;
+    // a records will be handled in either case, check for others like AAAA or CNAME
+    // TODO: add enums to this + a way to add custom types
+    return NON_STRICT_REPLACE_ALL || a.type() == 28 || a.type() == 5;
 }
 
 void process_answers(std::vector<answer>& answers)
 {
     for (auto& a : answers)
     {
-        if (shouldReplace(a))
+        if (a.type() == 1)
+        {
             a.substitute(REPLACEMENT_IP());
+        } else if (!STRICT_FILTERING && shouldReplace(a))
+        {
+            a.setARecord(REPLACEMENT_IP());
+        }
     }
 }
 
@@ -363,6 +396,7 @@ int main()
                 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);
@@ -370,10 +404,14 @@ int main()
             
             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);
-            BLT_TRACE("%d - %d = %d", out_bytes, reader2.last(), out_bytes - reader2.last());
+            }
             send.write(reader2.from(), out_bytes - reader2.last());
             
             asio::error_code ignored_error;