Return a distinct error from ERR_NAME_NOT_RESOLVED when the call to getaddrinfo() has unexpectedly failed.

For example when the system returns WSA_NOT_ENOUGH_MEMORY, we will now show ERR_NAME_RESOLUTION_FAILED rather than ERR_NAME_NOT_RESOLVED.
This allows propagating the error to the user, rather than simply showing them say the linkdoctor page as if the domain they entered was incorrect.

The data shows that a small number of users are getting these sorts of unexpected failures, and I want to get more visibility into it. By having a separate error code we can track how often this actually floats up onto an error page (as opposed to just errors on non-essential background requests).

On Linux we also see EAI_AGAIN with some frequency. My theory is that these occur when you DNS resolve immediately after the network change notification was broadcast (since I can repro this 100% on my laptop). If this is in fact the major cause, then once I land this new error we should NOT see an influx of ERR_NAME_RESOLUTION_FAILED in Net.ErrorCodesForMainFrame.

Review URL: http://codereview.chromium.org/3781005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@62705 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 19 insertions, 5 deletions

diff --git a/net/base/host_resolver_impl.cc b/net/base/host_resolver_impl.cc
index ffacb22..70f946f 100644
--- a/net/base/host_resolver_impl.cc
+++ b/net/base/host_resolver_impl.cc
@@ -487,7 +487,7 @@ class HostResolverImpl::Job
     // Ideally the following code would be part of host_resolver_proc.cc,
     // however it isn't safe to call NetworkChangeNotifier from worker
     // threads. So we do it here on the IO thread instead.
-    if (error_ == ERR_NAME_NOT_RESOLVED && NetworkChangeNotifier::IsOffline())
+    if (error_ != OK && NetworkChangeNotifier::IsOffline())
       error_ = ERR_INTERNET_DISCONNECTED;
 
     base::TimeDelta job_duration = base::TimeTicks::Now() - start_time_;
diff --git a/net/base/host_resolver_proc.cc b/net/base/host_resolver_proc.cc
index c2235c3..f33195c 100644
--- a/net/base/host_resolver_proc.cc
+++ b/net/base/host_resolver_proc.cc
@@ -235,13 +235,24 @@ int SystemHostResolverProc(const std::string& host,
   }
 
   if (err) {
-    if (os_error) {
 #if defined(OS_WIN)
-      *os_error = WSAGetLastError();
-#else
+    err = WSAGetLastError();
+#endif
+
+    // Return the OS error to the caller.
+    if (os_error)
       *os_error = err;
+
+    // If the call to getaddrinfo() failed because of a system error, report
+    // it separately from ERR_NAME_NOT_RESOLVED.
+#if defined(OS_WIN)
+    if (err != WSAHOST_NOT_FOUND && err != WSANO_DATA)
+      return ERR_NAME_RESOLUTION_FAILED;
+#elif defined(OS_POSIX)
+    if (err != EAI_NONAME && err != EAI_NODATA)
+      return ERR_NAME_RESOLUTION_FAILED;
 #endif
-    }
+
     return ERR_NAME_NOT_RESOLVED;
   }
 
diff --git a/net/base/net_error_list.h b/net/base/net_error_list.h
index 018cd77..d7ae9d1 100644
--- a/net/base/net_error_list.h
+++ b/net/base/net_error_list.h
@@ -205,6 +205,9 @@ NET_ERROR(SSL_CLIENT_AUTH_CERT_NO_PRIVATE_KEY, -135)
 // The certificate presented by the HTTPS Proxy was invalid.
 NET_ERROR(PROXY_CERTIFICATE_INVALID, -136)
 
+// An error occurred when trying to do a name resolution (DNS).
+NET_ERROR(NAME_RESOLUTION_FAILED, -137)
+
 // Certificate error codes
 //
 // The values of certificate error codes must be consecutive.