Enable reading ECN on mvfst client on windows using recvmmsg wrapper …

…path Summary: Previously, none of the read paths supported by QuicClienTransport had support for reaching the ToS field on Windows. This change adds support for reading ToS fields in the `shouldUseWrapperRecvmmsgForBatchRecv` read path on Windows. This facilitates running and testing ECN/L4S in a Windows-only environment. Reviewed By: kvtsoy, sharmafb Differential Revision: D66045131 fbshipit-source-id: 440cf99b5b97d852286630668abac906ea696950
facebook · Nov 21, 2024 · 4569046 · 4569046
1 parent f72ceb8
commit 4569046
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Showing 3 changed files with 39 additions and 5 deletions.
diff --git a/quic/common/udpsocket/QuicAsyncUDPSocket.cpp b/quic/common/udpsocket/QuicAsyncUDPSocket.cpp
@@ -11,6 +11,26 @@
 
 namespace quic {
 
+#if _WIN32
+// Folly netops exposes Windows control messages using the same struct field
+// names used by Linux. This defines macros to use these field names on Windows.
+
+#define FOLLY_CMSG_FIRSTHDR(msg)                 \
+  (((msg)->msg_controllen >= sizeof(WSACMSGHDR)) \
+       ? (LPWSACMSGHDR)(msg)->msg_control        \
+       : (LPWSACMSGHDR)NULL)
+
+#define FOLLY_CMSG_NXTHDR(msg, cmsg)                               \
+  (((cmsg) == NULL)                                                \
+       ? FOLLY_CMSG_FIRSTHDR(msg)                                  \
+       : ((((PUCHAR)(cmsg) + WSA_CMSGHDR_ALIGN((cmsg)->cmsg_len) + \
+            sizeof(WSACMSGHDR)) >                                  \
+           (PUCHAR)((msg)->msg_control) + (msg)->msg_controllen)   \
+              ? (LPWSACMSGHDR)NULL                                 \
+              : (LPWSACMSGHDR)((PUCHAR)(cmsg) +                    \
+                               WSA_CMSGHDR_ALIGN((cmsg)->cmsg_len))))
+#endif
+
 template <typename T, typename>
 T* QuicAsyncUDPSocket::getTypedSocket() const {
   auto sock = dynamic_cast<T*>(this);
@@ -25,7 +45,17 @@ T* QuicAsyncUDPSocket::getTypedSocket() const {
 void QuicAsyncUDPSocket::fromMsg(
     [[maybe_unused]] ReadCallback::OnDataAvailableParams& params,
     [[maybe_unused]] struct msghdr& msg) {
-#ifdef FOLLY_HAVE_MSG_ERRQUEUE
+#ifdef _WIN32
+  PCMSGHDR cmsg = FOLLY_CMSG_FIRSTHDR(&msg);
+  while (cmsg != NULL) {
+    if ((cmsg->cmsg_level == IPPROTO_IP && cmsg->cmsg_type == IP_TOS) ||
+        (cmsg->cmsg_level == IPPROTO_IPV6 && cmsg->cmsg_type == IPV6_TCLASS)) {
+      params.tos = *(PINT)WSA_CMSG_DATA(cmsg);
+      break;
+    }
+    cmsg = FOLLY_CMSG_NXTHDR(&msg, cmsg);
+  }
+#elif defined(FOLLY_HAVE_MSG_ERRQUEUE)
   struct cmsghdr* cmsg;
   uint16_t* grosizeptr;
   for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != nullptr;

diff --git a/quic/common/udpsocket/QuicAsyncUDPSocket.h b/quic/common/udpsocket/QuicAsyncUDPSocket.h
@@ -44,7 +44,11 @@ class QuicAsyncUDPSocket {
       using Timestamp = std::array<struct timespec, 3>;
       std::optional<Timestamp> ts;
       uint8_t tos = 0;
-#ifdef FOLLY_HAVE_MSG_ERRQUEUE
+#ifdef _WIN32
+      // Make control message space for ToS
+      static constexpr size_t kCmsgSpace = CMSG_SPACE(sizeof(INT));
+#elif defined(FOLLY_HAVE_MSG_ERRQUEUE)
+      // Make control message space for GRO, timestamp, and ToS
       static constexpr size_t kCmsgSpace = CMSG_SPACE(sizeof(uint16_t)) +
           CMSG_SPACE(sizeof(Timestamp)) + CMSG_SPACE(sizeof(uint8_t));
 #endif

diff --git a/quic/common/udpsocket/QuicAsyncUDPSocketImpl.cpp b/quic/common/udpsocket/QuicAsyncUDPSocketImpl.cpp
@@ -27,7 +27,7 @@ QuicAsyncUDPSocket::RecvResult QuicAsyncUDPSocketImpl::recvmmsgNetworkData(
   recvmmsgStorage_.resize(numPackets);
   auto& msgs = recvmmsgStorage_.msgs;
   int flags = 0;
-#ifdef FOLLY_HAVE_MSG_ERRQUEUE
+#if defined(FOLLY_HAVE_MSG_ERRQUEUE) || defined(_WIN32)
   bool useGRO = getGRO() > 0;
   bool checkCmsgs = useGRO || getTimestamping() > 0 || getRecvTos();
   std::vector<std::array<
@@ -59,7 +59,7 @@ QuicAsyncUDPSocket::RecvResult QuicAsyncUDPSocketImpl::recvmmsgNetworkData(
     rawAddr->sa_family = address().getFamily();
     msg->msg_name = rawAddr;
     msg->msg_namelen = kAddrLen;
-#ifdef FOLLY_HAVE_MSG_ERRQUEUE
+#if defined(FOLLY_HAVE_MSG_ERRQUEUE) || defined(_WIN32)
     if (checkCmsgs) {
       ::memset(controlVec[i].data(), 0, controlVec[i].size());
       msg->msg_control = controlVec[i].data();
@@ -95,7 +95,7 @@ QuicAsyncUDPSocket::RecvResult QuicAsyncUDPSocketImpl::recvmmsgNetworkData(
       continue;
     }
     QuicAsyncUDPSocket::ReadCallback::OnDataAvailableParams params;
-#ifdef FOLLY_HAVE_MSG_ERRQUEUE
+#if defined(FOLLY_HAVE_MSG_ERRQUEUE) || defined(_WIN32)
     if (checkCmsgs) {
       QuicAsyncUDPSocket::fromMsg(params, msg.msg_hdr);