From 035ecdc9e285ad2fd9ccf51e4ed2ac01b53dc3d1 Mon Sep 17 00:00:00 2001
From: peterbell10 <peterbell10@live.co.uk>
Date: Thu, 15 Jun 2017 10:03:49 +0100
Subject: Replace evdns with getaddrinfo and getnameinfo (#3766)

---
 src/OSSupport/IPLookup.cpp | 91 +++++++++++++++++++---------------------------
 1 file changed, 38 insertions(+), 53 deletions(-)

(limited to 'src/OSSupport/IPLookup.cpp')

diff --git a/src/OSSupport/IPLookup.cpp b/src/OSSupport/IPLookup.cpp
index 2722d4722..7b543793d 100644
--- a/src/OSSupport/IPLookup.cpp
+++ b/src/OSSupport/IPLookup.cpp
@@ -5,8 +5,9 @@
 
 #include "Globals.h"
 #include "IPLookup.h"
-#include <event2/dns.h>
+#include <event2/util.h>
 #include "NetworkSingleton.h"
+#include "GetAddressInfoError.h"
 
 
 
@@ -15,8 +16,9 @@
 ////////////////////////////////////////////////////////////////////////////////
 // cIPLookup:
 
-cIPLookup::cIPLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks):
-	m_Callbacks(a_Callbacks)
+cIPLookup::cIPLookup(const AString & a_IP, cNetwork::cResolveNameCallbacksPtr a_Callbacks):
+	m_Callbacks(a_Callbacks),
+	m_IP(a_IP)
 {
 	ASSERT(a_Callbacks != nullptr);
 }
@@ -25,68 +27,58 @@ cIPLookup::cIPLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks):
 
 
 
-bool cIPLookup::Lookup(const AString & a_IP)
+void cIPLookup::Lookup(const AString & a_IP, cNetwork::cResolveNameCallbacksPtr a_Callbacks)
 {
-	// Parse the IP address string into a sockaddr structure:
-	m_IP = a_IP;
-	sockaddr_storage sa;
-	int salen = static_cast<int>(sizeof(sa));
-	memset(&sa, 0, sizeof(sa));
-	if (evutil_parse_sockaddr_port(a_IP.c_str(), reinterpret_cast<sockaddr *>(&sa), &salen) != 0)
-	{
-		LOGD("Failed to parse IP address \"%s\".", a_IP.c_str());
-		return false;
-	}
+	cIPLookupPtr Lookup{ new cIPLookup(a_IP, std::move(a_Callbacks)) };  // Cannot use std::make_shared here, constructor is not accessible
 
-	// Call the proper resolver based on the address family:
-	// Note that there's no need to store the evdns_request handle returned, LibEvent frees it on its own.
-	switch (sa.ss_family)
+	// Note the Lookup object is owned solely by this lambda which is destroyed after it runs
+	cNetworkSingleton::Get().GetLookupThread().ScheduleLookup([=]()
 	{
-		case AF_INET:
-		{
-			sockaddr_in * sa4 = reinterpret_cast<sockaddr_in *>(&sa);
-			evdns_base_resolve_reverse(cNetworkSingleton::Get().GetDNSBase(), &(sa4->sin_addr), 0, Callback, this);
-			break;
-		}
-		case AF_INET6:
-		{
-			sockaddr_in6 * sa6 = reinterpret_cast<sockaddr_in6 *>(&sa);
-			evdns_base_resolve_reverse_ipv6(cNetworkSingleton::Get().GetDNSBase(), &(sa6->sin6_addr), 0, Callback, this);
-			break;
-		}
-		default:
+		sockaddr_storage sa;
+		int salen = sizeof(sa);
+		memset(&sa, 0, sizeof(sa));
+
+		int ErrCode = evutil_parse_sockaddr_port(Lookup->m_IP.c_str(), reinterpret_cast<sockaddr *>(&sa), &salen);
+
+		if (ErrCode != 0)
 		{
-			LOGWARNING("%s: Unknown address family: %d", __FUNCTION__, sa.ss_family);
-			ASSERT(!"Unknown address family");
-			return false;
+			LOGD("Failed to parse IP address \"%s\".", Lookup->m_IP.c_str());
+			Lookup->Callback(ErrCode, nullptr);
+			return;
 		}
-	}  // switch (address family)
-	return true;
+
+		char Hostname[NI_MAXHOST];
+		char ServInfo[NI_MAXSERV];
+
+		ErrCode = getnameinfo(
+			reinterpret_cast<sockaddr *>(&sa),
+			static_cast<socklen_t>(salen),
+			Hostname, sizeof(Hostname),
+			ServInfo, sizeof(ServInfo),
+			0
+		);
+		Lookup->Callback(ErrCode, Hostname);
+	});
 }
 
 
 
 
 
-void cIPLookup::Callback(int a_Result, char a_Type, int a_Count, int a_Ttl, void * a_Addresses, void * a_Self)
+void cIPLookup::Callback(int a_Result, const char * a_Address)
 {
-	// Get the Self class:
-	cIPLookup * Self = reinterpret_cast<cIPLookup *>(a_Self);
-	ASSERT(Self != nullptr);
-
 	// Call the proper callback based on the event received:
-	if ((a_Result != 0) || (a_Addresses == nullptr))
+	if ((a_Result != 0) || (a_Address == nullptr))
 	{
 		// An error has occurred, notify the error callback:
-		Self->m_Callbacks->OnError(a_Result, evutil_socket_error_to_string(a_Result));
+		m_Callbacks->OnError(a_Result, ErrorString(a_Result));
 	}
 	else
 	{
 		// Call the success handler:
-		Self->m_Callbacks->OnNameResolved(*(reinterpret_cast<char **>(a_Addresses)), Self->m_IP);
-		Self->m_Callbacks->OnFinished();
+		m_Callbacks->OnNameResolved(a_Address, m_IP);
+		m_Callbacks->OnFinished();
 	}
-	cNetworkSingleton::Get().RemoveIPLookup(Self);
 }
 
 
@@ -101,14 +93,7 @@ bool cNetwork::IPToHostName(
 	cNetwork::cResolveNameCallbacksPtr a_Callbacks
 )
 {
-	auto res = std::make_shared<cIPLookup>(a_Callbacks);
-	cNetworkSingleton::Get().AddIPLookup(res);
-	if (!res->Lookup(a_IP))
-	{
-		// Lookup failed early on, remove the object completely:
-		cNetworkSingleton::Get().RemoveIPLookup(res.get());
-		return false;
-	}
+	cIPLookup::Lookup(a_IP, std::move(a_Callbacks));
 	return true;
 }
 
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