Bypass data reduction proxy when using VPN

components/data_reduction_proxy/browser/data_reduction_proxy_settings.cc

Index: components/data_reduction_proxy/browser/data_reduction_proxy_settings.cc
diff --git a/components/data_reduction_proxy/browser/data_reduction_proxy_settings.cc b/components/data_reduction_proxy/browser/data_reduction_proxy_settings.cc
index b4299655cc85e30a93f0d9a0960453d96046b4d3..1d1d70f6abbae11a3f675039a8c0eb5a8e8cabfe 100644
--- a/components/data_reduction_proxy/browser/data_reduction_proxy_settings.cc
+++ b/components/data_reduction_proxy/browser/data_reduction_proxy_settings.cc
@@ -24,6 +24,7 @@
 #include "net/base/host_port_pair.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
+#include "net/base/net_util.h"
 #include "net/http/http_network_session.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_fetcher.h"
@@ -36,6 +37,14 @@
 using base::StringPrintf;
 
 namespace {
+// Values of the UMA DataReductionProxy.NetworkChangeEvents histograms.
+// This enum must remain synchronized with the enum of the same
+// name in metrics/histograms/histograms.xml.
+enum DataReductionProxyNetworkChangeEvent {
+  IP_CHANGED = 0, // The client IP address changed.
+  DISABLED_ON_VPN = 1, // The proxy is disabled because a VPN is running.
+  CHANGE_EVENT_COUNT = 2 // This must always be last.
+};
 
 // Key of the UMA DataReductionProxy.StartupState histogram.
 const char kUMAProxyStartupStateHistogram[] =
@@ -44,6 +53,13 @@ const char kUMAProxyStartupStateHistogram[] =
 // Key of the UMA DataReductionProxy.ProbeURL histogram.
 const char kUMAProxyProbeURL[] = "DataReductionProxy.ProbeURL";
 
+// Record a network change event.
+void RecordNetworkChangeEvent(DataReductionProxyNetworkChangeEvent event) {
+  UMA_HISTOGRAM_ENUMERATION("DataReductionProxy.NetworkChangeEvents",
+                            event,
+                            CHANGE_EVENT_COUNT);
+}
+
 int64 GetInt64PrefValue(const base::ListValue& list_value, size_t index) {
   int64 val = 0;
   std::string pref_value;
@@ -70,10 +86,10 @@ DataReductionProxySettings::DataReductionProxySettings(
     DataReductionProxyParams* params)
     : restricted_by_carrier_(false),
       enabled_by_user_(false),
+      disabled_on_vpn_(false),
       prefs_(NULL),
       local_state_prefs_(NULL),
-      url_request_context_getter_(NULL),
-      usage_stats_(NULL) {
+      url_request_context_getter_(NULL) {
   DCHECK(params);
   params_.reset(params);
 }
@@ -312,6 +328,9 @@ void DataReductionProxySettings::OnIPAddressChanged() {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (enabled_by_user_) {
     DCHECK(params_->allowed());
+    RecordNetworkChangeEvent(IP_CHANGED);
+    if (DisableIfVPN())
+      return;
     ProbeWhetherDataReductionProxyIsAvailable();
     WarmProxyConnection();
   }
@@ -360,13 +379,13 @@ void DataReductionProxySettings::MaybeActivateDataReductionProxy(
 
   // Configure use of the data reduction proxy if it is enabled.
   enabled_by_user_= IsDataReductionProxyEnabled();
-  SetProxyConfigs(enabled_by_user_,
+  SetProxyConfigs(enabled_by_user_ && !disabled_on_vpn_,
                   IsDataReductionProxyAlternativeEnabled(),
                   restricted_by_carrier_,
                   at_startup);
 
   // Check if the proxy has been restricted explicitly by the carrier.
-  if (enabled_by_user_) {
+  if (enabled_by_user_ && !disabled_on_vpn_) {
     ProbeWhetherDataReductionProxyIsAvailable();
     WarmProxyConnection();
   }
@@ -426,6 +445,12 @@ void DataReductionProxySettings::RecordStartupState(ProxyStartupState state) {
                             PROXY_STARTUP_STATE_COUNT);
 }
 
+void DataReductionProxySettings::GetNetworkList(
+    net::NetworkInterfaceList* interfaces,
+    int policy) {
+  net::GetNetworkList(interfaces, policy);
+}
+
 void DataReductionProxySettings::ResetParamsForTest(
     DataReductionProxyParams* params) {
   params_.reset(params);
@@ -486,18 +511,6 @@ void DataReductionProxySettings::GetContentLengths(
       local_state->GetInt64(prefs::kDailyHttpContentLengthLastUpdateDate);
 }
 
-// static
-base::string16 DataReductionProxySettings::AuthHashForSalt(
-    int64 salt,
-    const std::string& key) {
-  std::string salted_key =
-      base::StringPrintf("%lld%s%lld",
-                         static_cast<long long>(salt),
-                         key.c_str(),
-                         static_cast<long long>(salt));
-  return base::UTF8ToUTF16(base::MD5String(salted_key));
-}
-
 net::URLFetcher* DataReductionProxySettings::GetBaseURLFetcher(
     const GURL& gurl,
     int load_flags) {
@@ -543,4 +556,36 @@ void DataReductionProxySettings::WarmProxyConnection() {
   warmup_fetcher_->Start();
 }
 
+bool DataReductionProxySettings::DisableIfVPN() {
+  net::NetworkInterfaceList network_interfaces;
+  GetNetworkList(&network_interfaces, 0);
+  // VPNs use a "tun" interface, so the presence of a "tun" interface indicates
+  // a VPN is in use.
+  // TODO(kundaji): Verify this works on Windows.
+  const std::string vpn_interface_name_prefix = "tun";
+  for (size_t i = 0; i < network_interfaces.size(); ++i) {
+    std::string interface_name = network_interfaces[i].name;
+    if (LowerCaseEqualsASCII(
+        interface_name.begin(),
+        interface_name.begin() + vpn_interface_name_prefix.size(),
+        vpn_interface_name_prefix.c_str())) {
+      SetProxyConfigs(false,
+                      IsDataReductionProxyAlternativeEnabled(),
+                      false,
+                      false);
+      disabled_on_vpn_ = true;
+      RecordNetworkChangeEvent(DISABLED_ON_VPN);
+      return true;
+    }
+  }
+  if (disabled_on_vpn_) {
+    SetProxyConfigs(enabled_by_user_,
+                    IsDataReductionProxyAlternativeEnabled(),
+                    restricted_by_carrier_,
+                    false);
+  }
+  disabled_on_vpn_ = false;
+  return false;
+}
+
 }  // namespace data_reduction_proxy