From 467c6a09964df702e5a09ed4112c2475fc9048ea Mon Sep 17 00:00:00 2001
From: Steven Dwy <yoplitein+git@gmail.com>
Date: Mon, 16 Mar 2020 05:04:40 -0700
Subject: [PATCH] resolveHost: Check expected address family on returned
 address

The code as is never checks the requested address family when doing a DNS query,
so resolving an IPv6 only host with AddressFamily.INET would still return an IPv6.
---
 source/vibe/core/net.d                        | 12 ++++--
 .../pull-218-resolvehost-dns-address-family.d | 39 +++++++++++++++++++
 2 files changed, 47 insertions(+), 4 deletions(-)
 create mode 100644 tests/pull-218-resolvehost-dns-address-family.d

diff --git a/source/vibe/core/net.d b/source/vibe/core/net.d
index c8b2727..8295a0f 100644
--- a/source/vibe/core/net.d
+++ b/source/vibe/core/net.d
@@ -58,10 +58,14 @@ NetworkAddress resolveHost(string host, ushort address_family, bool use_dns = tr
 			cb => eventDriver.dns.lookupHost(host, cb),
 			(cb, id) => eventDriver.dns.cancelLookup(id),
 			(DNSLookupID, DNSStatus status, scope RefAddress[] addrs) {
-				if (status == DNSStatus.ok && addrs.length > 0) {
-					try res = NetworkAddress(addrs[0]);
-					catch (Exception e) { logDiagnostic("Failed to store address from DNS lookup: %s", e.msg); }
-					success = true;
+				if (status == DNSStatus.ok) {
+					foreach (addr; addrs) {
+						if (address_family != AddressFamily.UNSPEC && addr.addressFamily != address_family) continue;
+						try res = NetworkAddress(addr);
+						catch (Exception e) { logDiagnostic("Failed to store address from DNS lookup: %s", e.msg); }
+						success = true;
+						break;
+					}
 				}
 			}
 		);
diff --git a/tests/pull-218-resolvehost-dns-address-family.d b/tests/pull-218-resolvehost-dns-address-family.d
new file mode 100644
index 0000000..7d978fb
--- /dev/null
+++ b/tests/pull-218-resolvehost-dns-address-family.d
@@ -0,0 +1,39 @@
+/+ dub.sdl:
+    name "test"
+    dependency "vibe-core" path=".."
++/
+module test;
+
+import std.socket: AddressFamily;
+
+import vibe.core.core;
+import vibe.core.net;
+
+void main()
+{
+    runTask({
+        scope(exit) exitEventLoop();
+
+        auto addr = resolveHost("ip6.me", AddressFamily.INET);
+        assert(addr.family == AddressFamily.INET);
+
+        addr = resolveHost("ip6.me", AddressFamily.INET6);
+        assert(addr.family == AddressFamily.INET6);
+
+        try
+        {
+            resolveHost("ip4only.me", AddressFamily.INET6);
+            assert(false);
+        }
+        catch(Exception) {}
+
+        try
+        {
+            resolveHost("ip6only.me", AddressFamily.INET);
+            assert(false);
+        }
+        catch(Exception) {}
+    });
+
+    runEventLoop();
+}