Add UDP socket buffer size options to HQServerParams

Summary:
Add udpSendBufferSize and udpRecvBufferSize parameters to HQServerParams
to allow configuring SO_SNDBUF and SO_RCVBUF socket options on the underlying
QUIC server sockets. This enables tuning buffer sizes for high-throughput
scenarios without requiring custom socket factory implementations.

Reviewed By: kvtsoy

Differential Revision: D91237656

fbshipit-source-id: 9287e5367778c974bd9c08652fb65767350b6350

Author: afrind

proxygen/httpserver/samples/hq/HQParams.h

@@ -82,6 +82,9 @@ struct HQServerParams : public HQBaseParams {
   size_t serverThreads{0};
   std::string ccpConfig;
   folly::Optional<int64_t> rateLimitPerThread;
+  // UDP socket buffer sizes (0 = use system default)
+  size_t udpSendBufferSize{0};
+  size_t udpRecvBufferSize{0};
 };
 
 struct HQClientParams : public HQBaseParams {

proxygen/httpserver/samples/hq/HQServer.cpp

@@ -10,6 +10,7 @@
 
 #include <ostream>
 
+#include <folly/io/SocketOptionMap.h>
 #include <quic/common/udpsocket/FollyQuicAsyncUDPSocket.h>
 #include <string>
 #include <vector>
@@ -285,6 +286,22 @@ HQServer::HQServer(
   server_->setSupportedVersion(params_.quicVersions);
   server_->setFizzContext(std::move(fizzCtx));
 
+  // Apply UDP socket buffer size options if specified
+  folly::SocketOptionMap socketOptions;
+  if (params_.udpRecvBufferSize > 0) {
+    socketOptions[{
+        SOL_SOCKET, SO_RCVBUF, folly::SocketOptionKey::ApplyPos::POST_BIND}] =
+        static_cast<int>(params_.udpRecvBufferSize);
+  }
+  if (params_.udpSendBufferSize > 0) {
+    socketOptions[{
+        SOL_SOCKET, SO_SNDBUF, folly::SocketOptionKey::ApplyPos::POST_BIND}] =
+        static_cast<int>(params_.udpSendBufferSize);
+  }
+  if (!socketOptions.empty()) {
+    server_->setSocketOptions(socketOptions);
+  }
+
   if (params_.rateLimitPerThread) {
     server_->setRateLimit(
         [rateLimitPerThread = params_.rateLimitPerThread.value()]() {