Add listner fd as part of the external connection parameters

include/grpcpp/server_builder_impl.h

@@ -67,6 +67,7 @@ class CallbackGenericService;
 class ExternalConnectionAcceptor {
  public:
   struct NewConnectionParameters {
+    int listener_fd = -1;
     int fd = -1;
     ByteBuffer read_buffer;  // data intended for the grpc server
   };

src/core/lib/iomgr/tcp_server.h

@@ -41,6 +41,7 @@ typedef struct grpc_tcp_server_acceptor {
   unsigned fd_index;
   /* Data when the connection is passed to tcp_server from external. */
   bool external_connection;
+  int listener_fd;
   grpc_byte_buffer* pending_data;
 } grpc_tcp_server_acceptor;
 
@@ -55,7 +56,8 @@ namespace grpc_core {
 class TcpServerFdHandler {
  public:
   virtual ~TcpServerFdHandler() = default;
-  virtual void Handle(int fd, grpc_byte_buffer* pending_read) GRPC_ABSTRACT;
+  virtual void Handle(int listener_fd, int fd,
+                      grpc_byte_buffer* pending_read) GRPC_ABSTRACT;
 
   GRPC_ABSTRACT_BASE_CLASS;
 };

src/core/lib/iomgr/tcp_server_posix.cc

@@ -572,7 +572,7 @@ class ExternalConnectionHandler : public grpc_core::TcpServerFdHandler {
   explicit ExternalConnectionHandler(grpc_tcp_server* s) : s_(s) {}
 
   // TODO(yangg) resolve duplicate code with on_read
-  void Handle(int fd, grpc_byte_buffer* buf) override {
+  void Handle(int listener_fd, int fd, grpc_byte_buffer* buf) override {
     grpc_pollset* read_notifier_pollset;
     grpc_resolved_address addr;
     char* addr_str;
@@ -606,6 +606,7 @@ class ExternalConnectionHandler : public grpc_core::TcpServerFdHandler {
     acceptor->port_index = -1;
     acceptor->fd_index = -1;
     acceptor->external_connection = true;
+    acceptor->listener_fd = listener_fd;
     acceptor->pending_data = buf;
     s_->on_accept_cb(s_->on_accept_cb_arg,
                      grpc_tcp_create(fdobj, s_->channel_args, addr_str),

src/cpp/server/external_connection_acceptor_impl.cc

@@ -71,7 +71,7 @@ void ExternalConnectionAcceptorImpl::HandleNewConnection(
     return;
   }
   if (handler_) {
-    handler_->Handle(p->fd, p->read_buffer.c_buffer());
+    handler_->Handle(p->listener_fd, p->fd, p->read_buffer.c_buffer());
   }
 }
 

test/cpp/end2end/port_sharing_end2end_test.cc

@@ -159,6 +159,8 @@ class TestTcpServer {
     gpr_log(GPR_INFO, "Got incoming connection! from %s", peer);
     gpr_free(peer);
     EXPECT_FALSE(acceptor->external_connection);
+    listener_fd_ = grpc_tcp_server_port_fd(
+        acceptor->from_server, acceptor->port_index, acceptor->fd_index);
     gpr_free(acceptor);
     grpc_tcp_destroy_and_release_fd(tcp, &fd_, &on_fd_released_);
   }
@@ -166,6 +168,7 @@ class TestTcpServer {
   void OnFdReleased(grpc_error* err) {
     EXPECT_EQ(GRPC_ERROR_NONE, err);
     experimental::ExternalConnectionAcceptor::NewConnectionParameters p;
+    p.listener_fd = listener_fd_;
     p.fd = fd_;
     if (queue_data_) {
       char buf[1024];
@@ -176,14 +179,15 @@ class TestTcpServer {
       Slice data(buf, read_bytes);
       p.read_buffer = ByteBuffer(&data, 1);
     }
-    gpr_log(GPR_INFO, "Handing off fd %d with data size %d", fd_,
-            static_cast<int>(p.read_buffer.Length()));
+    gpr_log(GPR_INFO, "Handing off fd %d with data size %d from listener fd %d",
+            fd_, static_cast<int>(p.read_buffer.Length()), listener_fd_);
     connection_acceptor_->HandleNewConnection(&p);
   }
 
   std::mutex mu_;
   bool shutdown_;
 
+  int listener_fd_;
   int fd_;
   bool queue_data_;