Bug 1581637 - Part 5 - Add Http3 prefs. r=mayhemer

Differential Revision: https://phabricator.services.mozilla.com/D46651

--HG--
extra : moz-landing-system : lando

mobile/android/app/mobile.js

@@ -98,6 +98,9 @@ pref("network.http.max-persistent-connections-per-proxy", 20);
 pref("network.http.spdy.push-allowance", 32768);
 pref("network.http.spdy.default-hpack-buffer", 4096); // 4k
 
+// http3
+pref("network.http.http3.default-qpack-table-size", 4096); // 4k
+
 // See bug 545869 for details on why these are set the way they are
 pref("network.buffer.cache.count", 24);
 pref("network.buffer.cache.size",  16384);

modules/libpref/init/all.js

@@ -1406,6 +1406,14 @@ pref("network.http.spdy.default-hpack-buffer", 65536); // 64k
 pref("network.http.spdy.websockets", true);
 pref("network.http.spdy.enable-hpack-dump", false);
 
+// Http3 parameters
+pref("network.http.http3.enabled", false);
+// Http3 qpack table size.
+pref("network.http.http3.default-qpack-table-size", 65536); // 64k
+// Maximal number of streams that can be blocked on waiting for qpack
+// instructions.
+pref("network.http.http3.default-max-stream-blocked", 10);
+
 // alt-svc allows separation of transport routing from
 // the origin host without using a proxy.
 pref("network.http.altsvc.enabled", true);

netwerk/protocol/http/nsHttpHandler.cpp

@@ -280,6 +280,9 @@ nsHttpHandler::nsHttpHandler()
       mBug1563538(true),
       mBug1563695(true),
       mBug1556491(true),
+      mHttp3Enabled(true),
+      mQpackTableSize(4096),
+      mHttp3MaxBlockedStreams(10),
       mMaxHttpResponseHeaderSize(393216),
       mFocusedWindowTransactionRatio(0.9f),
       mSpeculativeConnectEnabled(false),
@@ -1917,6 +1920,28 @@ void nsHttpHandler::PrefsChanged(const char* pref) {
     }
   }
 
+  if (PREF_CHANGED(HTTP_PREF("http3.enabled"))) {
+    rv = Preferences::GetBool(HTTP_PREF("http3.enabled"), &cVar);
+    if (NS_SUCCEEDED(rv)) {
+      mHttp3Enabled = cVar;
+    }
+  }
+
+  if (PREF_CHANGED(HTTP_PREF("http3.default-qpack-table-size"))) {
+    rv = Preferences::GetInt(HTTP_PREF("http3.default-qpack-table-size"), &val);
+    if (NS_SUCCEEDED(rv)) {
+      mQpackTableSize = val;
+    }
+  }
+
+  if (PREF_CHANGED(HTTP_PREF("http3.default-max-stream-blocked"))) {
+    rv = Preferences::GetInt(HTTP_PREF("http3.default-max-stream-blocked"),
+                             &val);
+    if (NS_SUCCEEDED(rv)) {
+      mHttp3MaxBlockedStreams = clamped(val, 0, 0xffff);
+    }
+  }
+
   // Enable HTTP response timeout if TCP Keepalives are disabled.
   mResponseTimeoutEnabled =
       !mTCPKeepaliveShortLivedEnabled && !mTCPKeepaliveLongLivedEnabled;

netwerk/protocol/http/nsHttpHandler.h

@@ -439,6 +439,12 @@ class nsHttpHandler final : public nsIHttpProtocolHandler,
   bool IsHttp3VersionSupportedHex(const nsACString& version);
   nsCString Http3Version() { return kHttp3Version; }
 
+  bool IsHttp3Enabled() const { return mHttp3Enabled; }
+  uint32_t DefaultQpackTableSize() const { return mQpackTableSize; }
+  uint16_t DefaultHttp3MaxBlockedStreams() const {
+    return (uint16_t)mHttp3MaxBlockedStreams;
+  }
+
   uint32_t MaxHttpResponseHeaderSize() const {
     return mMaxHttpResponseHeaderSize;
   }
@@ -689,6 +695,13 @@ class nsHttpHandler final : public nsIHttpProtocolHandler,
   Atomic<bool, Relaxed> mBug1563695;
   Atomic<bool, Relaxed> mBug1556491;
 
+  Atomic<bool, Relaxed> mHttp3Enabled;
+  // Http3 parameters
+  Atomic<uint32_t, Relaxed> mQpackTableSize;
+  Atomic<uint32_t, Relaxed>
+      mHttp3MaxBlockedStreams;  // uint16_t is enough here, but Atomic only
+                                // supports uint32_t or uint64_t.
+
   // The max size (in bytes) for received Http response header.
   uint32_t mMaxHttpResponseHeaderSize;