Monero addres from DNS TXT record implemented, tests pass

Still need to deal with DNSSEC and optional fields in the TXT record.

src/common/dns_utils.cpp

@@ -34,6 +34,22 @@
 namespace tools
 {
 
+// custom smart pointer.
+// TODO: see if std::auto_ptr and the like support custom destructors
+class ub_result_ptr
+{
+public:
+  ub_result_ptr()
+  {
+    ptr = nullptr;
+  }
+  ~ub_result_ptr()
+  {
+    ub_resolve_free(ptr);
+  }
+  ub_result* ptr;
+};
+
 struct DNSResolverData
 {
   ub_ctx* m_ub_context;
@@ -63,20 +79,22 @@ DNSResolver::~DNSResolver()
 
 std::vector<std::string> DNSResolver::get_ipv4(const std::string& url)
 {
-  ub_result* result = NULL;
+  // destructor takes care of cleanup
+  ub_result_ptr result;
+
   std::vector<std::string> retval;
 
   // call DNS resolver, blocking.  if return value not zero, something went wrong
-  if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_A, LDNS_RR_CLASS_IN, &result))
+  if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_A, LDNS_RR_CLASS_IN, &(result.ptr)))
   {
-    if (result->havedata)
+    if (result.ptr->havedata)
     {
-      for (int i=0; result->data[i] != NULL; i++)
+      for (int i=0; result.ptr->data[i] != NULL; i++)
       {
         char as_str[INET_ADDRSTRLEN];
 
         // convert bytes to string, append if no error
-        if (inet_ntop(AF_INET, result->data[i], as_str, sizeof(as_str)))
+        if (inet_ntop(AF_INET, result.ptr->data[i], as_str, sizeof(as_str)))
         {
           retval.push_back(as_str);
         }
@@ -84,27 +102,25 @@ std::vector<std::string> DNSResolver::get_ipv4(const std::string& url)
     }
   }
 
-  // cleanup
-  ub_resolve_free(result);
   return retval;
 }
 
 std::vector<std::string> DNSResolver::get_ipv6(const std::string& url)
 {
-  ub_result* result = NULL;
+  ub_result_ptr result;
   std::vector<std::string> retval;
 
   // call DNS resolver, blocking.  if return value not zero, something went wrong
-  if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_AAAA, LDNS_RR_CLASS_IN, &result))
+  if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_AAAA, LDNS_RR_CLASS_IN, &(result.ptr)))
   {
-    if (result->havedata)
+    if (result.ptr->havedata)
     {
-      for (int i=0; result->data[i] != NULL; i++)
+      for (int i=0; result.ptr->data[i] != NULL; i++)
       {
         char as_str[INET6_ADDRSTRLEN];
 
         // convert bytes to string, append if no error
-        if (inet_ntop(AF_INET6, result->data[i], as_str, sizeof(as_str)))
+        if (inet_ntop(AF_INET6, result.ptr->data[i], as_str, sizeof(as_str)))
         {
           retval.push_back(as_str);
         }
@@ -112,15 +128,22 @@ std::vector<std::string> DNSResolver::get_ipv6(const std::string& url)
     }
   }
 
-  // cleanup
-  ub_resolve_free(result);
   return retval;
 }
 
-std::string DNSResolver::get_payment_address(const std::string& url)
+std::string DNSResolver::get_txt_record(const std::string& url)
 {
-  std::string retval;
+  ub_result_ptr result;
-  return retval;
+
+  // call DNS resolver, blocking.  if return value not zero, something went wrong
+  if (!ub_resolve(m_data->m_ub_context, url.c_str(), LDNS_RR_TYPE_TXT, LDNS_RR_CLASS_IN, &(result.ptr)))
+  {
+    if (result.ptr->havedata)
+    {
+      return std::string(result.ptr->data[0]);
+    }
+  }
+  return std::string();
 }
 
 DNSResolver& DNSResolver::instance()

src/common/dns_utils.h

@@ -82,17 +82,15 @@ public:
    std::vector<std::string> get_ipv6(const std::string& url);
 
   /**
-   * @brief gets a monero address from the TXT record of the DNS query response
+   * @brief gets a TXT record from a DNS query for the supplied URL;
-   *
+   * if no TXT record present returns an empty string.
-   * returns a monero address string from the TXT record associated with URL
-   * if no TXT record present, or no valid monero address in TXT,
-   * returns an empty string.
    *
    * @param url A string containing a URL to query for
    *
-   * @return 
+   * @return A string containing a TXT record; or an empty string
    */
-  std::string get_payment_address(const std::string& url);
+  // TODO: modify this to accomodate DNSSEC
+  std::string get_txt_record(const std::string& url);
 
   /**
    * @brief Gets the singleton instance of DNSResolver

src/wallet/wallet2.cpp

@@ -47,6 +47,7 @@ using namespace epee;
 #include "serialization/binary_utils.h"
 #include "cryptonote_protocol/blobdatatype.h"
 #include "crypto/electrum-words.h"
+#include "common/dns_utils.h"
 
 extern "C"
 {
@@ -751,6 +752,7 @@ void wallet2::add_unconfirmed_tx(const cryptonote::transaction& tx, uint64_t cha
   utd.m_sent_time = time(NULL);
   utd.m_tx = tx;
 }
+
 //----------------------------------------------------------------------------------------------------
 void wallet2::transfer(const std::vector<cryptonote::tx_destination_entry>& dsts, size_t fake_outputs_count,
                        uint64_t unlock_time, uint64_t fee, const std::vector<uint8_t>& extra, cryptonote::transaction& tx, pending_tx& ptx)
@@ -815,6 +817,58 @@ std::vector<std::vector<cryptonote::tx_destination_entry>> split_amounts(
 }
 } // anonymous namespace
 
+/**
+ * @brief gets a monero address from the TXT record of a DNS entry
+ *
+ * gets the monero address from the TXT record of the DNS entry associated
+ * with <url>.  If this lookup fails, or the TXT record does not contain an
+ * XMR address in the correct format, returns an empty string.  <dnssec_valid>
+ * will be set true or false according to whether or not the DNS query passes
+ * DNSSEC validation.
+ *
+ * @param url the url to look up
+ * @param dnssec_valid return-by-reference for DNSSEC status of query
+ *
+ * @return a monero address (as a string) or an empty string
+ */
+std::string wallet2::address_from_url(const std::string& url, bool& dnssec_valid)
+{
+  // TODO: update this correctly once DNSResolver::get_txt_record() supports it.
+  dnssec_valid = false;
+  // get txt record
+  std::string txt = tools::DNSResolver::instance().get_txt_record(url);
+
+  if (txt.size())
+  {
+    return address_from_txt_record(txt);
+  }
+  return std::string();
+}
+
+//----------------------------------------------------------------------------------------------------
+std::string wallet2::address_from_txt_record(const std::string& s)
+{
+  // make sure the txt record has "oa1:xmr" and find it
+  auto pos = s.find("oa1:xmr");
+
+  // search from there to find "recipient_address="
+  pos = s.find("recipient_address=", pos);
+
+  pos += 18; // move past "recipient_address="
+
+  // find the next semicolon
+  auto pos2 = s.find(";", pos);
+  if (pos2 != std::string::npos)
+  {
+    // length of address == 95, we can at least validate that much here
+    if (pos2 - pos == 95)
+    {
+      return s.substr(pos, 95);
+    }
+  }
+  return std::string();
+}
+
 //----------------------------------------------------------------------------------------------------
 // take a pending tx and actually send it to the daemon
 void wallet2::commit_tx(pending_tx& ptx)

src/wallet/wallet2.h

@@ -196,6 +196,9 @@ namespace tools
 
     static bool parse_payment_id(const std::string& payment_id_str, crypto::hash& payment_id);
 
+    static std::string address_from_url(const std::string& url, bool& dnssec_valid);
+
+    static std::string address_from_txt_record(const std::string& s);
   private:
     bool store_keys(const std::string& keys_file_name, const std::string& password);
     void load_keys(const std::string& keys_file_name, const std::string& password);

tests/unit_tests/address_from_url.cpp

@@ -0,0 +1,102 @@
+// Copyright (c) 2014, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. 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.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// 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 HOLDER 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.
+
+// FIXME: move this into a full wallet2 unit test suite, if possible
+
+#include "gtest/gtest.h"
+
+#include "wallet/wallet2.h"
+#include <string>
+
+TEST(AddressFromTXT, Success)
+{
+  std::string addr = "46BeWrHpwXmHDpDEUmZBWZfoQpdc6HaERCNmx1pEYL2rAcuwufPN9rXHHtyUA4QVy66qeFQkn6sfK8aHYjA3jk3o1Bv16em";
+
+  std::string txtr = "oa1:xmr";
+  txtr += " recipient_address=";
+  txtr += addr;
+  txtr += ";";
+
+  std::string res = tools::wallet2::address_from_txt_record(txtr);
+
+  EXPECT_STREQ(addr.c_str(), res.c_str());
+
+  std::string txtr2 = "foobar";
+
+  txtr2 += txtr;
+
+  txtr2 += "more foobar";
+
+  res = tools::wallet2::address_from_txt_record(txtr2);
+
+  EXPECT_STREQ(addr.c_str(), res.c_str());
+
+  std::string txtr3 = "foobar oa1:xmr tx_description=\"Donation for Monero Development Fund\"; ";
+  txtr3 += "recipient_address=";
+  txtr3 += addr;
+  txtr3 += "; foobar";
+
+  res = tools::wallet2::address_from_txt_record(txtr3);
+
+  EXPECT_STREQ(addr.c_str(), res.c_str());
+}
+
+TEST(AddressFromTXT, Failure)
+{
+  std::string txtr = "oa1:xmr recipient_address=not a real address";
+
+  std::string res = tools::wallet2::address_from_txt_record(txtr);
+
+  ASSERT_STREQ("", res.c_str());
+
+  txtr += ";";
+
+  res = tools::wallet2::address_from_txt_record(txtr);
+  ASSERT_STREQ("", res.c_str());
+}
+
+TEST(AddressFromURL, Success)
+{
+  std::string addr = "46BeWrHpwXmHDpDEUmZBWZfoQpdc6HaERCNmx1pEYL2rAcuwufPN9rXHHtyUA4QVy66qeFQkn6sfK8aHYjA3jk3o1Bv16em";
+  
+  bool dnssec_result = false;
+  std::string res = tools::wallet2::address_from_url("donate.monero.cc", dnssec_result);
+
+  EXPECT_STREQ(addr.c_str(), res.c_str());
+}
+
+TEST(AddressFromURL, Failure)
+{
+  bool dnssec_result = false;
+
+  std::string res = tools::wallet2::address_from_url("example.invalid", dnssec_result);
+
+  ASSERT_FALSE(dnssec_result);
+
+  ASSERT_STREQ("", res.c_str());
+}

tests/unit_tests/dns_resolver.cpp

@@ -1,3 +1,33 @@
+// Copyright (c) 2014, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. 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.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// 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 HOLDER 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.
+
+#include <iostream>
+
 #include "gtest/gtest.h"
 
 #include "common/dns_utils.h"
@@ -63,3 +93,12 @@ TEST(DNSResolver, IPv6Failure)
 
   ASSERT_EQ(0, ips.size());
 }
+
+TEST(DNSResolver, GetTXTRecord)
+{
+
+  std::string txt = tools::DNSResolver::instance().get_txt_record("donate.monero.cc");
+  std::cout << "TXT record for donate.monero.cc: " << txt << std::endl;
+
+  EXPECT_STRNE("", txt.c_str());
+}