1 files changed, 231 insertions, 0 deletions
diff --git a/src/common/dns_utils.cpp b/src/common/dns_utils.cpp
new file mode 100644
index 000000000..346761e74
--- /dev/null
+++ b/src/common/dns_utils.cpp
@@ -0,0 +1,231 @@
+// 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 "common/dns_utils.h"
+#include <cstring>
+#include <sstream>
+#include <unbound.h>
+
+namespace tools
+{
+
+// fuck it, I'm tired of dealing with getnameinfo()/inet_ntop/etc
+std::string ipv4_to_string(const char* src)
+{
+  std::stringstream ss;
+  unsigned int bytes[4];
+  for (int i = 0; i < 4; i++)
+  {
+    unsigned char a = src[i];
+    bytes[i] = a;
+  }
+  ss << bytes[0] << "."
+     << bytes[1] << "."
+     << bytes[2] << "."
+     << bytes[3];
+  return ss.str();
+}
+
+// this obviously will need to change, but is here to reflect the above
+// stop-gap measure and to make the tests pass at least...
+std::string ipv6_to_string(const char* src)
+{
+  std::stringstream ss;
+  unsigned int bytes[8];
+  for (int i = 0; i < 8; i++)
+  {
+    unsigned char a = src[i];
+    bytes[i] = a;
+  }
+  ss << bytes[0] << ":"
+     << bytes[1] << ":"
+     << bytes[2] << ":"
+     << bytes[3] << ":"
+     << bytes[4] << ":"
+     << bytes[5] << ":"
+     << bytes[6] << ":"
+     << bytes[7];
+  return ss.str();
+}
+
+// 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;
+};
+
+DNSResolver::DNSResolver() : m_data(new DNSResolverData())
+{
+  // init libunbound context
+  m_data->m_ub_context = ub_ctx_create();
+
+  char empty_string = '\0';
+
+  // look for "/etc/resolv.conf" and "/etc/hosts" or platform equivalent
+  ub_ctx_resolvconf(m_data->m_ub_context, &empty_string);
+  ub_ctx_hosts(m_data->m_ub_context, &empty_string);
+}
+
+DNSResolver::~DNSResolver()
+{
+  if (m_data)
+  {
+    if (m_data->m_ub_context != NULL)
+    {
+      ub_ctx_delete(m_data->m_ub_context);
+    }
+    delete m_data;
+  }
+}
+
+std::vector<std::string> DNSResolver::get_ipv4(const std::string& url)
+{
+  std::vector<std::string> addresses;
+  char urlC[1000];  // waaaay too big, but just in case...
+
+  strncpy(urlC, url.c_str(), 999);
+  urlC[999] = '\0';
+  if (!check_address_syntax(urlC))
+  {
+    return addresses;
+  }
+
+  // destructor takes care of cleanup
+  ub_result_ptr result;
+
+  // call DNS resolver, blocking.  if return value not zero, something went wrong
+  if (!ub_resolve(m_data->m_ub_context, urlC, DNS_TYPE_A, DNS_CLASS_IN, &(result.ptr)))
+  {
+    if (result.ptr->havedata)
+    {
+      for (size_t i=0; result.ptr->data[i] != NULL; i++)
+      {
+        addresses.push_back(ipv4_to_string(result.ptr->data[i]));
+      }
+    }
+  }
+
+  return addresses;
+}
+
+std::vector<std::string> DNSResolver::get_ipv6(const std::string& url)
+{
+  std::vector<std::string> addresses;
+  char urlC[1000];  // waaaay too big, but just in case...
+
+  strncpy(urlC, url.c_str(), 999);
+  urlC[999] = '\0';
+
+  if (!check_address_syntax(urlC))
+  {
+    return addresses;
+  }
+
+  ub_result_ptr result;
+
+  // call DNS resolver, blocking.  if return value not zero, something went wrong
+  if (!ub_resolve(m_data->m_ub_context, urlC, DNS_TYPE_AAAA, DNS_CLASS_IN, &(result.ptr)))
+  {
+    if (result.ptr->havedata)
+    {
+      for (size_t i=0; result.ptr->data[i] != NULL; i++)
+      {
+        addresses.push_back(ipv6_to_string(result.ptr->data[i]));
+      }
+    }
+  }
+
+  return addresses;
+}
+
+std::vector<std::string> DNSResolver::get_txt_record(const std::string& url)
+{
+  std::vector<std::string> records;
+  char urlC[1000];  // waaaay too big, but just in case...
+
+  strncpy(urlC, url.c_str(), 999);
+  urlC[999] = '\0';
+
+  if (!check_address_syntax(urlC))
+  {
+    return records;
+  }
+
+  ub_result_ptr result;
+
+  // call DNS resolver, blocking.  if return value not zero, something went wrong
+  if (!ub_resolve(m_data->m_ub_context, urlC, DNS_TYPE_TXT, DNS_CLASS_IN, &(result.ptr)))
+  {
+    if (result.ptr->havedata)
+    {
+      for (size_t i=0; result.ptr->data[i] != NULL; i++)
+      {
+        records.push_back(result.ptr->data[i]);
+      }
+    }
+  }
+
+  return records;
+}
+
+DNSResolver& DNSResolver::instance()
+{
+  static DNSResolver* staticInstance = NULL;
+  if (staticInstance == NULL)
+  {
+    staticInstance = new DNSResolver();
+  }
+  return *staticInstance;
+}
+
+bool DNSResolver::check_address_syntax(const std::string& addr)
+{
+  // if string doesn't contain a dot, we won't consider it a url for now.
+  if (addr.find(".") == std::string::npos)
+  {
+    return false;
+  }
+  return true;
+}
+
+}  // namespace tools