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//
// DNS.cpp
//
// $Id: //poco/1.4/Net/src/DNS.cpp#10 $
//
// Library: Net
// Package: NetCore
// Module: DNS
//
// Copyright (c) 2005-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
#include "Poco/Net/DNS.h"
#include "Poco/Net/NetException.h"
#include "Poco/Net/SocketAddress.h"
#include "Poco/Environment.h"
#include "Poco/NumberFormatter.h"
#include "Poco/AtomicCounter.h"
#include <cstring>
using Poco::FastMutex;
using Poco::Environment;
using Poco::NumberFormatter;
using Poco::IOException;
namespace
{
class NetworkInitializer
{
public:
NetworkInitializer()
{
Poco::Net::initializeNetwork();
}
~NetworkInitializer()
{
Poco::Net::uninitializeNetwork();
}
};
}
namespace Poco {
namespace Net {
HostEntry DNS::hostByName(const std::string& hostname)
{
NetworkInitializer networkInitializer;
#if defined(POCO_HAVE_IPv6) || defined(POCO_HAVE_ADDRINFO)
struct addrinfo* pAI;
struct addrinfo hints;
std::memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_CANONNAME | AI_ADDRCONFIG;
int rc = getaddrinfo(hostname.c_str(), NULL, &hints, &pAI);
if (rc == 0)
{
HostEntry result(pAI);
freeaddrinfo(pAI);
return result;
}
else
{
aierror(rc, hostname);
}
#elif defined(POCO_VXWORKS)
int addr = hostGetByName(const_cast<char*>(hostname.c_str()));
if (addr != ERROR)
{
return HostEntry(hostname, IPAddress(&addr, sizeof(addr)));
}
#else
struct hostent* he = gethostbyname(hostname.c_str());
if (he)
{
return HostEntry(he);
}
#endif
error(lastError(), hostname); // will throw an appropriate exception
throw NetException(); // to silence compiler
}
HostEntry DNS::hostByAddress(const IPAddress& address)
{
NetworkInitializer networkInitializer;
#if defined(POCO_HAVE_IPv6) || defined(POCO_HAVE_ADDRINFO)
SocketAddress sa(address, 0);
static char fqname[1024];
int rc = getnameinfo(sa.addr(), sa.length(), fqname, sizeof(fqname), NULL, 0, NI_NAMEREQD);
if (rc == 0)
{
struct addrinfo* pAI;
struct addrinfo hints;
std::memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_CANONNAME | AI_ADDRCONFIG;
rc = getaddrinfo(fqname, NULL, &hints, &pAI);
if (rc == 0)
{
HostEntry result(pAI);
freeaddrinfo(pAI);
return result;
}
else
{
aierror(rc, address.toString());
}
}
else
{
aierror(rc, address.toString());
}
#elif defined(POCO_VXWORKS)
char name[MAXHOSTNAMELEN + 1];
if (hostGetByAddr(*reinterpret_cast<const int*>(address.addr()), name) == OK)
{
return HostEntry(std::string(name), address);
}
#else
struct hostent* he = gethostbyaddr(reinterpret_cast<const char*>(address.addr()), address.length(), address.af());
if (he)
{
return HostEntry(he);
}
#endif
int err = lastError();
error(err, address.toString()); // will throw an appropriate exception
throw NetException(); // to silence compiler
}
HostEntry DNS::resolve(const std::string& address)
{
NetworkInitializer networkInitializer;
IPAddress ip;
if (IPAddress::tryParse(address, ip))
return hostByAddress(ip);
else
return hostByName(address);
}
IPAddress DNS::resolveOne(const std::string& address)
{
NetworkInitializer networkInitializer;
const HostEntry& entry = resolve(address);
if (!entry.addresses().empty())
return entry.addresses()[0];
else
throw NoAddressFoundException(address);
}
HostEntry DNS::thisHost()
{
return hostByName(hostName());
}
void DNS::flushCache()
{
}
std::string DNS::hostName()
{
NetworkInitializer networkInitializer;
char buffer[256];
int rc = gethostname(buffer, sizeof(buffer));
if (rc == 0)
return std::string(buffer);
else
throw NetException("Cannot get host name");
}
int DNS::lastError()
{
#if defined(_WIN32)
return GetLastError();
#elif defined(POCO_VXWORKS)
return errno;
#else
return h_errno;
#endif
}
void DNS::error(int code, const std::string& arg)
{
switch (code)
{
case POCO_ESYSNOTREADY:
throw NetException("Net subsystem not ready");
case POCO_ENOTINIT:
throw NetException("Net subsystem not initialized");
case POCO_HOST_NOT_FOUND:
throw HostNotFoundException(arg);
case POCO_TRY_AGAIN:
throw DNSException("Temporary DNS error while resolving", arg);
case POCO_NO_RECOVERY:
throw DNSException("Non recoverable DNS error while resolving", arg);
case POCO_NO_DATA:
throw NoAddressFoundException(arg);
default:
throw IOException(NumberFormatter::format(code));
}
}
void DNS::aierror(int code, const std::string& arg)
{
#if defined(POCO_HAVE_IPv6)
switch (code)
{
case EAI_AGAIN:
throw DNSException("Temporary DNS error while resolving", arg);
case EAI_FAIL:
throw DNSException("Non recoverable DNS error while resolving", arg);
#if !defined(_WIN32) // EAI_NODATA and EAI_NONAME have the same value
case EAI_NODATA:
throw NoAddressFoundException(arg);
#endif
case EAI_NONAME:
throw HostNotFoundException(arg);
#if defined(EAI_SYSTEM)
case EAI_SYSTEM:
error(lastError(), arg);
break;
#endif
#if defined(_WIN32)
case WSANO_DATA: // may happen on XP
throw HostNotFoundException(arg);
#endif
default:
throw DNSException("EAI", NumberFormatter::format(code));
}
#endif // POCO_HAVE_IPv6
}
#if defined(_WIN32)
static Poco::AtomicCounter initializeCount;
#endif
void initializeNetwork()
{
#if defined(_WIN32)
if (++initializeCount == 1)
{
WORD version = MAKEWORD(2, 2);
WSADATA data;
if (WSAStartup(version, &data) != 0)
throw NetException("Failed to initialize network subsystem");
}
#endif // _WIN32
}
void uninitializeNetwork()
{
#if defined(_WIN32)
if (--initializeCount == 0)
{
WSACleanup();
}
#endif // _WIN32
}
} } // namespace Poco::Net