Add support for UNIX datagram sockets to AsyncUDPSocket

Summary:
Add support for AF_UNIX datagram sockets in AsyncUDPSocket class.
For UNIX sockets, the third argument to the socket() call should be 0,
and getPort() throws. Fix these instances.

Reviewed By: yfeldblum

Differential Revision: D15073543

fbshipit-source-id: 14627d256a7f15104cbc22bc4b5ce03694c90405

folly/io/async/AsyncUDPSocket.cpp

@@ -56,8 +56,10 @@ AsyncUDPSocket::~AsyncUDPSocket() {
 }
 
 void AsyncUDPSocket::bind(const folly::SocketAddress& address) {
-  NetworkSocket socket =
-      netops::socket(address.getFamily(), SOCK_DGRAM, IPPROTO_UDP);
+  NetworkSocket socket = netops::socket(
+      address.getFamily(),
+      SOCK_DGRAM,
+      address.getFamily() != AF_UNIX ? IPPROTO_UDP : 0);
   if (socket == NetworkSocket()) {
     throw AsyncSocketException(
         AsyncSocketException::NOT_OPEN,
@@ -171,7 +173,7 @@ void AsyncUDPSocket::bind(const folly::SocketAddress& address) {
   // attach to EventHandler
   EventHandler::changeHandlerFD(fd_);
 
-  if (address.getPort() != 0) {
+  if (address.getFamily() == AF_UNIX || address.getPort() != 0) {
     localAddress_ = address;
   } else {
     localAddress_.setFromLocalAddress(fd_);

folly/io/async/test/AsyncUDPSocketTest.cpp

@@ -27,6 +27,7 @@
 #include <folly/portability/GMock.h>
 #include <folly/portability/GTest.h>
 #include <folly/portability/Sockets.h>
+#include <folly/portability/Unistd.h>
 
 using folly::AsyncTimeout;
 using folly::AsyncUDPServerSocket;
@@ -612,6 +613,19 @@ TEST_F(AsyncUDPSocketTest, TestBound) {
   EXPECT_TRUE(socket.isBound());
 }
 
+TEST_F(AsyncUDPSocketTest, TestBoundUnixSocket) {
+  const auto kTmpUnixSocketPath{"/tmp/tmp_unix_socket"};
+  AsyncUDPSocket socket(&evb_);
+  EXPECT_FALSE(socket.isBound());
+  SCOPE_EXIT {
+    ::unlink(kTmpUnixSocketPath);
+  };
+  ::unlink(kTmpUnixSocketPath);
+  socket.bind(folly::SocketAddress::makeFromPath(kTmpUnixSocketPath));
+  EXPECT_TRUE(socket.isBound());
+  socket.close();
+}
+
 TEST_F(AsyncUDPSocketTest, TestAttachAfterDetachEvbWithReadCallback) {
   socket_->resumeRead(&readCb);
   EXPECT_TRUE(socket_->isHandlerRegistered());