Bypass data reduction proxy if response not via it

The change verifies that a request sent to the data reduction
proxy has a corresponding response that contains the data
reduction proxy's Via header.

BUG=335633

Review URL: https://codereview.chromium.org/144653007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249184 0039d316-1c4b-4281-b951-d872f2087c98

net/http/http_network_layer_unittest.cc

@@ -99,7 +99,8 @@ class HttpNetworkLayerTest : public PlatformTest {
                       const std::string& bad_proxy2) {
     const ProxyRetryInfoMap& retry_info = proxy_service_->proxy_retry_info();
     ASSERT_EQ(proxy_count, retry_info.size());
-    ASSERT_TRUE(retry_info.find(bad_proxy) != retry_info.end());
+    if (proxy_count > 0)
+      ASSERT_TRUE(retry_info.find(bad_proxy) != retry_info.end());
     if (proxy_count > 1)
       ASSERT_TRUE(retry_info.find(bad_proxy2) != retry_info.end());
   }
@@ -135,7 +136,7 @@ class HttpNetworkLayerTest : public PlatformTest {
       MockRead data_reads[],
       int data_reads_size,
       std::string method,
-      std::string content,
+      std::string content_of_retry,
       bool retry_expected,
       unsigned int expected_retry_info_size) {
     std::string trailer =
@@ -160,8 +161,8 @@ class HttpNetworkLayerTest : public PlatformTest {
     size_t data_reads2_index = 0;
     data_reads2[data_reads2_index++] = MockRead("HTTP/1.0 200 OK\r\n"
                                                 "Server: not-proxy\r\n\r\n");
-    if (!content.empty())
-      data_reads2[data_reads2_index++] = MockRead(content.c_str());
+    if (!content_of_retry.empty())
+      data_reads2[data_reads2_index++] = MockRead(content_of_retry.c_str());
     data_reads2[data_reads2_index++] = MockRead(SYNCHRONOUS, OK);
 
     MockWrite data_writes2[] = {
@@ -174,7 +175,7 @@ class HttpNetworkLayerTest : public PlatformTest {
     // Expect that we get "content" and not "Bypass message", and that there's
     // a "not-proxy" "Server:" header in the final response.
     if (retry_expected) {
-      ExecuteRequestExpectingContentAndHeader(method, content,
+      ExecuteRequestExpectingContentAndHeader(method, content_of_retry,
                                               "server", "not-proxy");
     } else {
       ExecuteRequestExpectingContentAndHeader(method, "Bypass message", "", "");
@@ -621,7 +622,8 @@ TEST_F(HttpNetworkLayerTest, ServerFallbackWithProxyTimedBypass) {
   MockRead data_reads[] = {
     MockRead("HTTP/1.1 200 OK\r\n"
              "Connection: keep-alive\r\n"
-             "Chrome-Proxy: bypass=86400\r\n\r\n"),
+             "Chrome-Proxy: bypass=86400\r\n"
+             "Via: 1.1 Chrome Compression Proxy\r\n\r\n"),
     MockRead("Bypass message"),
     MockRead(SYNCHRONOUS, OK),
   };
@@ -632,6 +634,63 @@ TEST_F(HttpNetworkLayerTest, ServerFallbackWithProxyTimedBypass) {
             (*proxy_service_->proxy_retry_info().begin()).second.current_delay);
 }
 
+TEST_F(HttpNetworkLayerTest, ServerFallbackWithWrongViaHeader) {
+  // Verify that a Via header that lacks the Chrome-Proxy induces proxy fallback
+  // to a second proxy, if configured.
+  std::string chrome_proxy = GetChromeProxy();
+  ConfigureTestDependencies(ProxyService::CreateFixedFromPacResult(
+      "PROXY " + chrome_proxy + "; PROXY good:8080"));
+
+  MockRead data_reads[] = {
+    MockRead("HTTP/1.1 200 OK\r\n"
+             "Connection: keep-alive\r\n"
+             "Via: 1.0 some-other-proxy\r\n\r\n"),
+    MockRead("Bypass message"),
+    MockRead(SYNCHRONOUS, OK),
+  };
+
+  TestProxyFallbackWithMockReads(chrome_proxy, std::string(), data_reads,
+                                 arraysize(data_reads), 1u);
+}
+
+TEST_F(HttpNetworkLayerTest, ServerFallbackWithNoViaHeader) {
+  // Verify that the lack of a Via header induces proxy fallback to a second
+  // proxy, if configured.
+  std::string chrome_proxy = GetChromeProxy();
+  ConfigureTestDependencies(ProxyService::CreateFixedFromPacResult(
+      "PROXY " + chrome_proxy + "; PROXY good:8080"));
+
+  MockRead data_reads[] = {
+    MockRead("HTTP/1.1 200 OK\r\n"
+             "Connection: keep-alive\r\n\r\n"),
+    MockRead("Bypass message"),
+    MockRead(SYNCHRONOUS, OK),
+  };
+
+  TestProxyFallbackWithMockReads(chrome_proxy, std::string(), data_reads,
+                                 arraysize(data_reads), 1u);
+}
+
+TEST_F(HttpNetworkLayerTest, NoServerFallbackWithChainedViaHeader) {
+  // Verify that Chrome will not be induced to bypass the Chrome proxy when
+  // the Chrome Proxy via header is present, even if that header is chained.
+  std::string chrome_proxy = GetChromeProxy();
+  ConfigureTestDependencies(ProxyService::CreateFixedFromPacResult(
+      "PROXY " + chrome_proxy + "; PROXY good:8080"));
+
+  MockRead data_reads[] = {
+    MockRead("HTTP/1.1 200 OK\r\n"
+             "Connection: keep-alive\r\n"
+             "Via: 1.1 Chrome Compression Proxy, 1.0 some-other-proxy\r\n\r\n"),
+    MockRead("Bypass message"),
+    MockRead(SYNCHRONOUS, OK),
+  };
+
+  TestProxyFallbackByMethodWithMockReads(chrome_proxy, std::string(),
+                                         data_reads, arraysize(data_reads),
+                                         "GET", std::string(), false, 0);
+}
+
 #if defined(DATA_REDUCTION_FALLBACK_HOST)
 TEST_F(HttpNetworkLayerTest, ServerFallbackWithProxyTimedBypassAll) {
   // Verify that a Chrome-Proxy: block=<seconds> header bypasses a
@@ -646,7 +705,8 @@ TEST_F(HttpNetworkLayerTest, ServerFallbackWithProxyTimedBypassAll) {
   MockRead data_reads[] = {
     MockRead("HTTP/1.1 200 OK\r\n"
              "Connection: keep-alive\r\n"
-             "Chrome-Proxy: block=86400\r\n\r\n"),
+             "Chrome-Proxy: block=86400\r\n"
+             "Via: 1.1 Chrome Compression Proxy\r\n\r\n"),
     MockRead("Bypass message"),
     MockRead(SYNCHRONOUS, OK),
   };

net/http/http_network_transaction.cc

@@ -62,6 +62,7 @@
 #include "url/gurl.h"
 
 #if defined(SPDY_PROXY_AUTH_ORIGIN)
+#include <algorithm>
 #include "net/proxy/proxy_server.h"
 #endif
 
@@ -118,6 +119,30 @@ base::Value* NetLogSSLVersionFallbackCallback(
   return dict;
 }
 
+#if defined(SPDY_PROXY_AUTH_ORIGIN)
+// Returns true if |response_headers| contains the data reduction proxy Via
+// header value.
+bool IsChromeProxyResponse(const net::HttpResponseHeaders* response_headers) {
+  if (!response_headers) {
+    return false;
+  }
+  const char kDataReductionProxyViaValue[] = "1.1 Chrome Compression Proxy";
+  size_t value_len = strlen(kDataReductionProxyViaValue);
+  void* iter = NULL;
+  std::string temp;
+  while (response_headers->EnumerateHeader(&iter, "Via", &temp)) {
+    std::string::const_iterator it =
+        std::search(temp.begin(), temp.end(),
+                    kDataReductionProxyViaValue,
+                    kDataReductionProxyViaValue + value_len,
+                    base::CaseInsensitiveCompareASCII<char>());
+    if (it != temp.end())
+      return true;
+  }
+  return false;
+}
+#endif
+
 }  // namespace
 
 //-----------------------------------------------------------------------------
@@ -1018,14 +1043,16 @@ int HttpNetworkTransaction::DoReadHeadersComplete(int result) {
 #endif
 
     if (chrome_proxy_used || chrome_fallback_proxy_used) {
-      if (response_.headers->GetChromeProxyInfo(&chrome_proxy_info)) {
+      if (!IsChromeProxyResponse(response_.headers.get())) {
+        proxy_bypass_event = ProxyService::MISSING_VIA_HEADER;
+      } else if (response_.headers->GetChromeProxyInfo(&chrome_proxy_info)) {
         if (chrome_proxy_info.bypass_duration < TimeDelta::FromMinutes(30))
           proxy_bypass_event = ProxyService::SHORT_BYPASS;
         else
           proxy_bypass_event = ProxyService::LONG_BYPASS;
       } else {
         // Additionally, fallback if a 500, 502 or 503 is returned via the data
-        // reduction proxy. This is conservative, as the 500, 501 or 502 might
+        // reduction proxy. This is conservative, as the 500, 502 or 503 might
         // have been generated by the origin, and not the proxy.
         if (response_.headers->response_code() == HTTP_INTERNAL_SERVER_ERROR ||
             response_.headers->response_code() == HTTP_BAD_GATEWAY ||

net/proxy/proxy_service.h

@@ -286,6 +286,9 @@ class NET_EXPORT ProxyService : public NetworkChangeNotifier::IPAddressObserver,
     // Bypass the proxy because of any other error.
     ERROR_BYPASS,
 
+    // Bypass the proxy because responses appear not to be coming via it.
+    MISSING_VIA_HEADER,
+
     // This must always be last.
     BYPASS_EVENT_TYPE_MAX
   };

tools/metrics/histograms/histograms.xml

@@ -23265,6 +23265,7 @@ other types of suffix sets.
   <int value="1" label="Long bypass"/>
   <int value="2" label="Bypass due to internal server error"/>
   <int value="3" label="Bypass due to other error"/>
+  <int value="4" label="Bypass due to missing via header"/>
 </enum>
 
 <enum name="DataReductionProxyProbeURLFetchResult" type="int">