Merge pull request #34 from neuroscr/master

Reverse DNS support

include/llarp/dns_dotlokilookup.hpp

@@ -17,7 +17,9 @@ struct dotLokiLookup
 {
   /// for timers (MAYBEFIXME? maybe we decouple this, yes pls have a generic
   /// passed in)
+  // we can use DNSc for access to the logic
   struct llarp_logic *logic;
+
   /// which ip tracker to use
   struct dns_iptracker *ip_tracker;
 

include/llarp/handlers/tun.hpp

@@ -80,6 +80,10 @@ namespace llarp
       static void
       handleTickTun(void* u);
 
+      /// get a service address for ip address
+      service::Address
+      ObtainAddrForIP(huint32_t ip);
+
      protected:
       typedef llarp::util::CoDelQueue<
           net::IPv4Packet, net::IPv4Packet::GetTime, net::IPv4Packet::PutTime,
@@ -92,6 +96,7 @@ namespace llarp
       /// return true if we have a remote loki address for this ip address
       bool
       HasRemoteForIP(huint32_t ipv4) const;
+
       /// get ip address for service address unconditionally
       huint32_t
       ObtainIPForAddr(const service::Address& addr);

include/llarp/net.hpp

@@ -76,7 +76,7 @@ namespace llarp
 
     constexpr bool operator <(huint32_t x) const { return h < x.h; }
     constexpr bool operator ==(huint32_t x) const { return h == x.h; }
-    
+
     struct Hash
     {
       inline size_t
@@ -272,7 +272,7 @@ namespace llarp
   {
     // network order
     sockaddr_in6 _addr;
-    sockaddr_in _addr4;  // why do we even have this?
+    sockaddr_in _addr4;  // why do we even have this? favor cpu over memory
     ~Addr(){};
 
     Addr(){};

llarp/dns_dotlokilookup.cpp

@@ -43,7 +43,8 @@ llarp_dotlokilookup_checkQuery(void *u, uint64_t orig, uint64_t left)
   if(!dll)
   {
     llarp::LogError("DNSd dotLokiLookup is not configured");
-    // FIXME: send 404
+    write404_dnss_response(qr->from, qr->request);
+    delete qr;
     return;
   }
 
@@ -56,7 +57,7 @@ llarp_dotlokilookup_checkQuery(void *u, uint64_t orig, uint64_t left)
   {
     llarp::LogWarn("Could not base32 decode address: ",
                    qr->request->question.name);
-    // FIXME: send 404
+    write404_dnss_response(qr->from, qr->request);
     delete qr;
     return;
   }
@@ -64,7 +65,9 @@ llarp_dotlokilookup_checkQuery(void *u, uint64_t orig, uint64_t left)
   auto itr = loki_tld_lookup_cache.find(addr.ToString());
   if(itr != loki_tld_lookup_cache.end())
   {
+    llarp::LogDebug("Found in .loki lookup cache");
     writesend_dnss_response(itr->second->returnThis, qr->from, qr->request);
+    delete qr;
     return;
   }
 
@@ -93,13 +96,16 @@ llarp_dotlokilookup_checkQuery(void *u, uint64_t orig, uint64_t left)
     if(!routerHiddenServiceContext)
     {
       llarp::LogWarn("dotLokiLookup user isnt a service::Context: ", dll->user);
+      write404_dnss_response(qr->from, qr->request);
+      delete qr;
       return;
     }
     bool mapResult = routerHiddenServiceContext->MapAddressAll(
         addr, free_private->hostResult);
     if(!mapResult)
     {
-      // FIXME: send 404
+      llarp::LogWarn("dotLokiLookup failed to map address");
+      write404_dnss_response(qr->from, qr->request);
       delete qr;
       return;
     }
@@ -129,22 +135,158 @@ llarp_dotlokilookup_checkQuery(void *u, uint64_t orig, uint64_t left)
   delete qr;
 }
 
+std::vector< std::string >
+split(std::string str)
+{
+  size_t pos = 0;
+  std::string token;
+  std::string s(str);
+  std::vector< std::string > tokens;
+  while((pos = s.find(".")) != std::string::npos)
+  {
+    token = s.substr(0, pos);
+    // llarp::LogInfo("token [", token, "]");
+    tokens.push_back(token);
+    s.erase(0, pos + 1);
+  }
+  token = s.substr(0, pos);
+  tokens.push_back(token);
+  // llarp::LogInfo("token [", token, "]");
+  return tokens;
+}
+
+struct reverse_handler_iter_context
+{
+  std::string lName;
+  const struct sockaddr *from;
+  const struct dnsd_question_request *request;
+};
+
+bool
+ReverseHandlerIter(struct llarp::service::Context::endpoint_iter *endpointCfg)
+{
+  reverse_handler_iter_context *context =
+      (reverse_handler_iter_context *)endpointCfg->user;
+  // llarp::LogInfo("context ", context->request->question.name);
+  // llarp::LogInfo("Checking ", lName);
+  llarp::handlers::TunEndpoint *tunEndpoint =
+      (llarp::handlers::TunEndpoint *)endpointCfg->endpoint;
+  if(!tunEndpoint)
+  {
+    llarp::LogError("No tunnel endpoint found");
+    return true;  // still continue
+  }
+  // llarp::LogInfo("for ", tunEndpoint->tunif.ifaddr);
+  std::string checkStr(tunEndpoint->tunif.ifaddr);
+  std::vector< std::string > tokensSearch = split(context->lName);
+  std::vector< std::string > tokensCheck  = split(checkStr);
+
+  // well the tunif is just one ip on a network range...
+  // support "b._dns-sd._udp.0.0.200.10.in-addr.arpa"
+  size_t searchTokens  = tokensSearch.size();
+  std::string searchIp = tokensSearch[searchTokens - 3] + "."
+      + tokensSearch[searchTokens - 4] + "." + tokensSearch[searchTokens - 5]
+      + "." + tokensSearch[searchTokens - 6];
+  std::string checkIp = tokensCheck[0] + "." + tokensCheck[1] + "."
+      + tokensCheck[2] + "." + tokensCheck[3];
+  llarp::LogDebug(searchIp, " vs ", checkIp);
+
+  llarp::IPRange range = llarp::iprange_ipv4(
+      stoi(tokensCheck[0]), stoi(tokensCheck[1]), stoi(tokensCheck[2]),
+      stoi(tokensCheck[3]), tunEndpoint->tunif.netmask);  // create range
+  // hack atm to work around limitations in ipaddr_ipv4_bits and llarp::IPRange
+  llarp::huint32_t searchIPv4_fixed = llarp::ipaddr_ipv4_bits(
+      stoi(tokensSearch[searchTokens - 6]),
+      stoi(tokensSearch[searchTokens - 5]),
+      stoi(tokensSearch[searchTokens - 4]),
+      stoi(tokensSearch[searchTokens
+                        - 3]));  // create ip (llarp::Addr is untrustworthy atm)
+  llarp::huint32_t searchIPv4_search = llarp::ipaddr_ipv4_bits(
+      stoi(tokensSearch[searchTokens - 3]),
+      stoi(tokensSearch[searchTokens - 4]),
+      stoi(tokensSearch[searchTokens - 5]),
+      stoi(tokensSearch[searchTokens
+                        - 6]));  // create ip (llarp::Addr is untrustworthy atm)
+
+  // bool inRange = range.Contains(searchAddr.xtohl());
+  bool inRange = range.Contains(searchIPv4_search);
+
+  llarp::Addr searchAddr(searchIp);
+  llarp::Addr checkAddr(checkIp);
+  llarp::LogDebug(searchAddr, " vs ", range.ToString(), " = ",
+                  inRange ? "inRange" : "not match");
+
+  if(inRange)
+  {
+    llarp::service::Address addr =
+        tunEndpoint->ObtainAddrForIP(searchIPv4_fixed);
+    if(addr.ToString()
+       == "yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy.loki")
+    {
+      write404_dnss_response(context->from,
+                             (dnsd_question_request *)context->request);
+    }
+    else
+    {
+      writesend_dnss_revresponse(addr.ToString(), context->from,
+                                 (dnsd_question_request *)context->request);
+    }
+    return false;
+  }
+  return true;  // we don't do anything with the result yet
+}
+
 dnsd_query_hook_response *
 llarp_dotlokilookup_handler(std::string name, const struct sockaddr *from,
                             struct dnsd_question_request *const request)
 {
   dnsd_query_hook_response *response = new dnsd_query_hook_response;
-  // dotLokiLookup *dll                 = (dotLokiLookup
-  // *)request->context->user;
-  response->dontLookUp       = false;
-  response->dontSendResponse = false;
-  response->returnThis       = nullptr;
+  response->dontLookUp               = false;
+  response->dontSendResponse         = false;
+  response->returnThis               = nullptr;
   llarp::LogDebug("Hooked ", name);
   std::string lName = name;
   std::transform(lName.begin(), lName.end(), lName.begin(), ::tolower);
+  // llarp::LogDebug("Transformed ", lName);
+
+  // 253.0.200.10.in-addr.arpa
+  if(lName.find(".in-addr.arpa") != std::string::npos)
+  {
+    // llarp::LogDebug("Checking ", lName);
+    dotLokiLookup *dll = (dotLokiLookup *)request->context->user;
+    llarp::service::Context *routerHiddenServiceContext =
+        (llarp::service::Context *)dll->user;
+    if(!routerHiddenServiceContext)
+    {
+      llarp::LogWarn("dotLokiLookup user isnt a service::Context: ", dll->user);
+      return response;
+    }
+    // llarp::LogDebug("Starting rev iter for ", lName);
+    // which range?
+    // for each tun interface
+    struct reverse_handler_iter_context context;
+    context.lName   = lName;
+    context.from    = from;
+    context.request = request;
 
-  // FIXME: probably should just read the last 5 bytes
-  if(lName.find(".loki") != std::string::npos)
+    struct llarp::service::Context::endpoint_iter i;
+    i.user   = &context;
+    i.index  = 0;
+    i.visit  = &ReverseHandlerIter;
+    bool res = routerHiddenServiceContext->iterate(i);
+    if(!res)
+    {
+      llarp::LogInfo("Reverse is ours");
+      response->dontSendResponse = true;  // should have already sent it
+    }
+    else
+    {
+      llarp::LogInfo("Reverse is not ours");
+    }
+  }
+  else if((lName.length() > 5 && lName.substr(lName.length() - 5, 5) == ".loki")
+          || (lName.length() > 6
+              && lName.substr(lName.length() - 6, 6) == ".loki."))
   {
     llarp::LogInfo("Detect Loki Lookup for ", lName);
     auto cache_check = loki_tld_lookup_cache.find(lName);
@@ -179,7 +321,7 @@ llarp_dotlokilookup_handler(std::string name, const struct sockaddr *from,
     llarp_logic_call_later(request->context->client.logic,
                            {2000, qr, &llarp_dotlokilookup_checkQuery});
 
-    response->dontSendResponse = true;
+    response->dontSendResponse = true;  // will send it shortly
   }
   return response;
 }

llarp/handlers/tun.cpp

@@ -134,6 +134,7 @@ namespace llarp
       }
       llarp::LogInfo(Name() + " map ", addr.ToString(), " to ",
                      inet_ntoa({nip.n}));
+
       m_IPToAddr.insert(std::make_pair(ip, addr));
       m_AddrToIP.insert(std::make_pair(addr, ip));
       MarkIPActiveForever(ip);
@@ -351,6 +352,22 @@ namespace llarp
       return true;
     }
 
+    service::Address
+    TunEndpoint::ObtainAddrForIP(huint32_t ip)
+    {
+      auto itr = m_IPToAddr.find(ip);
+      if(itr == m_IPToAddr.end())
+      {
+        // not found
+        // llarp::Addr test(ip); // "/", test,
+        service::Address addr;
+        llarp::LogWarn(" not found in tun map. Sending ", addr.ToString());
+        return addr;
+      }
+      // found
+      return itr->second;
+    }
+
     huint32_t
     TunEndpoint::ObtainIPForAddr(const service::Address &addr)
     {

llarp/service/context.cpp

@@ -64,8 +64,8 @@ namespace llarp
       while(itr != m_Endpoints.end())
       {
         i.endpoint = itr->second.get();
-        i.visit(&i);
-
+        if(!i.visit(&i))
+          return false;
         // advance
         i.index++;
         itr++;
@@ -136,7 +136,7 @@ namespace llarp
     }
 
     bool
-    MappAddressAllIter(struct Context::endpoint_iter *endpointCfg)
+    MapAddressAllIter(struct Context::endpoint_iter *endpointCfg)
     {
       Context::mapAddressAll_context *context =
           (Context::mapAddressAll_context *)endpointCfg->user;
@@ -145,7 +145,7 @@ namespace llarp
       if(!tunEndpoint)
       {
         llarp::LogError("No tunnel endpoint found");
-        return false;
+        return true;  // still continue
       }
       return tunEndpoint->MapAddress(context->serviceAddr,
                                      context->localPrivateIpAddr.xtohl());
@@ -162,7 +162,7 @@ namespace llarp
       struct Context::endpoint_iter i;
       i.user  = &context;
       i.index = 0;
-      i.visit = &MappAddressAllIter;
+      i.visit = &MapAddressAllIter;
       return this->iterate(i);
     }
 

test/net_unittest.cpp

@@ -5,12 +5,25 @@ struct NetTest : public ::testing::Test
 {
 };
 
-TEST_F(NetTest, TestRangeContains)
+TEST_F(NetTest, TestRangeContains8)
 {
   ASSERT_TRUE(llarp::iprange_ipv4(10, 0, 0, 0, 8)
                   .Contains(llarp::ipaddr_ipv4_bits(10, 40, 11, 6)));
 }
 
+TEST_F(NetTest, TestRangeContains24)
+{
+  ASSERT_TRUE(llarp::iprange_ipv4(10, 200, 0, 1, 24)
+                  .Contains(llarp::ipaddr_ipv4_bits(10, 200, 0, 253)));
+}
+
+TEST_F(NetTest, TestRangeContainsFail)
+{
+  ASSERT_TRUE(!llarp::iprange_ipv4(192, 168, 0, 1, 24)
+                  .Contains(llarp::ipaddr_ipv4_bits(10, 200, 0, 253)));
+}
+
+
 TEST_F(NetTest, TestIPv4Netmask)
 {
   ASSERT_TRUE(llarp::xhtonl(llarp::netmask_ipv4_bits(8))