fix: windows porting - close socket fails

Author: SCLevi

go.work.sum

@@ -1,3 +1,5 @@
+github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
 github.com/spf13/cobra v1.7.0/go.mod h1:uLxZILRyS/50WlhOIKD7W6V5bgeIt+4sICxh6uRMrb0=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/tailscale/hujson v0.0.0-20221223112325-20486734a56a/go.mod h1:DFSS3NAGHthKo1gTlmEcSBiZrRJXi28rLNd/1udP1c8=

libtailscale.exe

@@ -4,6 +4,7 @@
 // or OS+any architecture respectively without needing a special comment
 package platform
 
+//#cgo CFLAGS: -g -Wall
 //#cgo LDFLAGS: -lws2_32
 //#include "errno.h"
 //#include "../socketpair_handler.h"
@@ -15,29 +16,35 @@ import (
 	"unsafe"
 )
 
-func GetSocketPair() ([2]int, error) {
-	var fds [2]int
+func GetSocketPair() ([]syscall.Handle, error) {
+	fds := make([]syscall.Handle, 2)
 	fds_pt := C.get_socket_pair()
-	fds_array := (*[1 << 30]int)(unsafe.Pointer(fds_pt))[:2:2]
-	fds[0] = fds_array[0]
-	fds[1] = fds_array[1]
+	fds_array := (*[2]C.SOCKET)(unsafe.Pointer(fds_pt))[:]
+	fds[0] = syscall.Handle(uintptr(fds_array[0]))
+	fds[1] = syscall.Handle(uintptr(fds_array[1]))
 	return fds, nil
 }
 
-func CloseSocket(fd interface{}) error {
-	fmt.Println("Closing socket", fd.(syscall.Handle))
-	return syscall.Close(fd.(syscall.Handle))
+func CloseSocket(fd syscall.Handle) error {
+	fmt.Println("Closing socket", fd)
+	err := syscall.Close(fd)
+	errCode := syscall.GetLastError()
+	// Handle the error or print it for debugging
+	fmt.Printf("Error closing handle: %v\n", errCode)
+	return err
 }
 
-func ReadSocket(fd interface{}, buf *[256]byte) {
-	syscall.Read(fd.(syscall.Handle), (*buf)[:])
+func ReadSocket(fd syscall.Handle, buf *[256]byte) {
+	fmt.Println("Reading socket", fd)
+	syscall.Read(fd, (*buf)[:])
 }
 
-func SendMessage(fd interface{}, p []byte, connFd int, to syscall.Sockaddr, flags int) error {
-	_, err := syscall.Write(fd.(syscall.Handle), p)
+func SendMessage(fd syscall.Handle, p []byte, connFd int, to syscall.Sockaddr, flags int) error {
+	fmt.Println("Writing socket", fd)
+	_, err := syscall.Write(fd, p)
 	return err
 }
 
-func Shutdown(fd interface{}, how int) error {
-	return syscall.Shutdown(fd.(syscall.Handle), how)
+func Shutdown(fd syscall.Handle, how int) error {
+	return syscall.Shutdown(fd, how)
 }

platform/tailscale_windows.go

@@ -49,6 +49,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include <string.h>
+#include <stdio.h>
 
 #ifdef _WIN32
 # include <ws2tcpip.h>  /* socklen_t, et al (MSVC20xx) */
@@ -76,23 +77,33 @@ static int dumb_socketpair(SOCKET socks[2], int make_overlapped)
        struct sockaddr_in inaddr;
        struct sockaddr addr;
     } a;
+    int iResult;
+    WSADATA wsaData;
+    iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
+    if (iResult != 0) {
+        printf("failed WSA startup");
+        return;
+    }
     SOCKET listener;
     int e;
     socklen_t addrlen = sizeof(a.inaddr);
     DWORD flags = (make_overlapped ? WSA_FLAG_OVERLAPPED : 0);
     int reuse = 1;
-
+    
     if (socks == 0) {
       WSASetLastError(WSAEINVAL);
       return SOCKET_ERROR;
     }
     socks[0] = socks[1] = -1;
-
+    printf("something");
     listener = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
-    if (listener == -1)
+    if (listener == -1) {
+        printf("something2");
+        printf("%d", WSAGetLastError());
         return SOCKET_ERROR;
-
+    }
     memset(&a, 0, sizeof(a));
+    printf("something");
     a.inaddr.sin_family = AF_INET;
     a.inaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
     a.inaddr.sin_port = 0;
@@ -124,17 +135,17 @@ static int dumb_socketpair(SOCKET socks[2], int make_overlapped)
         socks[1] = accept(listener, NULL, NULL);
         if (socks[1] == -1)
             break;
-
+        WSACleanup();
         closesocket(listener);
         return 0;
     }
-
     e = WSAGetLastError();
     closesocket(listener);
     closesocket(socks[0]);
     closesocket(socks[1]);
     WSASetLastError(e);
     socks[0] = socks[1] = -1;
+    WSACleanup();
     return SOCKET_ERROR;
 }
 #else

socketpair.c

@@ -1,4 +1,5 @@
 #ifdef _WIN32
+#include "socketpair_handler.h"
 #include "socketpair.c"
 #include <winsock2.h>
 #include <windows.h>
@@ -7,14 +8,23 @@
 #pragma comment(lib, "ws2_32.lib")
 #endif
 
-int *get_socket_pair() {
+SOCKET *get_socket_pair() {
 		#ifdef _WIN32
-			SOCKET spair[2];
+			SOCKET* spair = (SOCKET*)malloc(2 * sizeof(SOCKET));
+        	if (spair == NULL) {
+            	fprintf(stderr, "Failed to allocate memory for socket pair\n");
+            	return NULL;
+        	}
+
 			spair[0] = 0;
 			spair[1] = 0;
 			if(dumb_socketpair(spair, 1) == SOCKET_ERROR)
 				fprintf(stderr, "Init failed, creating socketpair: %s\n", strerror(errno));
+				free(spair);
 			return spair;
+		#else
+			return NULL;
 		#endif
-		return -1;
+		
+		
 }

socketpair_handler.c

@@ -1,6 +1,8 @@
 #ifndef SOCKET_H
 #define SOCKET_H
 
-int *get_socket_pair();
+#include<winsock2.h>
+
+SOCKET *get_socket_pair();
 
 #endif

socketpair_handler.h

@@ -59,7 +59,7 @@ var listeners struct {
 type listener struct {
 	s  *server
 	ln net.Listener
-	fd int // go side fd of socketpair sent to C
+	fd C.SOCKET // go side fd of socketpair sent to C
 }
 
 // conns tracks all the pipe(2)s allocated via tsnet_dial.
@@ -172,6 +172,7 @@ func TsnetErrmsg(sd C.int, buf *C.char, buflen C.size_t) C.int {
 
 //export TsnetListen
 func TsnetListen(sd C.int, network, addr *C.char, listenerOut *C.int) C.int {
+	fmt.Println("start listening")
 	s, err := getServer(sd)
 	if err != nil {
 		return s.recErr(err)
@@ -187,8 +188,7 @@ func TsnetListen(sd C.int, network, addr *C.char, listenerOut *C.int) C.int {
 	// feed an fd for the connection through the listener. This lets C use
 	// epoll on the tailscale_listener to know if it should call
 	// tailscale_accept, which avoids a blocking call on the far side.
-	var fds [2]int
-	fds, err = platform.GetSocketPair()
+	fds, err := platform.GetSocketPair()
 
 	if err != nil {
 		return s.recErr(err)
@@ -200,9 +200,9 @@ func TsnetListen(sd C.int, network, addr *C.char, listenerOut *C.int) C.int {
 	if listeners.m == nil {
 		listeners.m = map[C.int]*listener{}
 	}
-	listeners.m[fdC] = &listener{s: s, ln: ln, fd: sp}
+	listeners.m[fdC] = &listener{s: s, ln: ln, fd: C.SOCKET(sp)}
 	listeners.mu.Unlock()
-
+	fmt.Println("listener setup")
 	cleanup := func() {
 		// If fdC is closed on the C side, then we end up calling
 		// into cleanup twice. Be careful to avoid syscall.Close
@@ -252,7 +252,7 @@ func TsnetListen(sd C.int, network, addr *C.char, listenerOut *C.int) C.int {
 				netConn.Close()
 				// fallthrough to close connFd, then continue Accept()ing
 			}
-			platform.CloseSocket(int(connFd)) // now owned by recvmsg
+			//platform.CloseSocket(connFd) // now owned by recvmsg
 		}
 	}()
 
@@ -263,9 +263,8 @@ func TsnetListen(sd C.int, network, addr *C.char, listenerOut *C.int) C.int {
 func newConn(s *server, netConn net.Conn, connOut *C.int) error {
 
 	// TODO https://github.com/ncm/selectable-socketpair/blob/master/socketpair.c
-	var fds [2]int
 	var err error
-	fds, err = platform.GetSocketPair()
+	fds, err := platform.GetSocketPair()
 	if err != nil {
 		return err
 	}
@@ -300,7 +299,7 @@ func newConn(s *server, netConn net.Conn, connOut *C.int) error {
 		defer connCleanup()
 		var b [1 << 16]byte
 		io.CopyBuffer(r, netConn, b[:])
-		platform.Shutdown(int(r.Fd()), syscall.SHUT_WR)
+		platform.Shutdown(syscall.Handle(r.Fd()), syscall.SHUT_WR)
 		if cr, ok := netConn.(interface{ CloseRead() error }); ok {
 			cr.CloseRead()
 		}
@@ -309,7 +308,7 @@ func newConn(s *server, netConn net.Conn, connOut *C.int) error {
 		defer connCleanup()
 		var b [1 << 16]byte
 		io.CopyBuffer(netConn, r, b[:])
-		platform.Shutdown(int(r.Fd()), syscall.SHUT_RD)
+		platform.Shutdown(syscall.Handle(r.Fd()), syscall.SHUT_RD)
 		if cw, ok := netConn.(interface{ CloseWrite() error }); ok {
 			cw.CloseWrite()
 		}