apply all sockopts to listening sockets

Summary:
We want all socket options to be applied to the listen sockets too.

The old code here that only applied SO_KEEPALIVE is a bit superstitious.
Not all options will be inherited by accept()ed sockets, but that's
fine.  We set them again post-accept().

Applying all these options to the listening sockets will fix at least
one long standing bug, which is that QoS is not set correctly for the
first few packets in a flow.  This also will let us do the right thing
when we gain the ability to set TCP_MAXSEG in D1741753.

Test Plan: fbmake runtests & canary in prod

Reviewed By: afrind@fb.com, davejwatson@fb.com

Subscribers: jsedgwick, satadru, trunkagent, fugalh, exa, folly-diffs@, agartrell

FB internal diff: D1745182

Tasks: 2911597

Signature: t1:1745182:1418860157:045680a91b153482bcd4a014894fb28059955d06

diff --git a/folly/wangle/acceptor/Acceptor.cpp b/folly/wangle/acceptor/Acceptor.cpp
index 15807809a7c5d8175ebffdcd2160c9ca94e880a8..2d31e7196a2e5ac04ef506996311ba19047b8e23 100644 (file)
--- a/folly/wangle/acceptor/Acceptor.cpp
+++ b/folly/wangle/acceptor/Acceptor.cpp
@@ -190,13 +190,13 @@ Acceptor::init(AsyncServerSocket* serverSocket,
 
   if (serverSocket) {
     serverSocket->addAcceptCallback(this, eventBase);
-    // SO_KEEPALIVE is the only setting that is inherited by accepted
-    // connections so only apply this setting
-    for (const auto& option: socketOptions_) {
-      if (option.first.level == SOL_SOCKET &&
-          option.first.optname == SO_KEEPALIVE && option.second == 1) {
-        serverSocket->setKeepAliveEnabled(true);
-        break;
+
+    for (auto& fd : serverSocket->getSockets()) {
+      if (fd < 0) {
+        continue;
+      }
+      for (const auto& opt: socketOptions_) {
+        opt.first.apply(fd, opt.second);
       }
     }
   }