vsudd: Add support for Hyper-V sockets

- If a GUID is passed in use AF_HYPERV else AFVSOCK

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

alpine/packages/vsudd/main.go

@@ -8,6 +8,7 @@ import (
 	"net"
 	"os"
 	"strconv"
+	"strings"
 	"syscall"
 	"time"
 )
@@ -15,6 +16,7 @@ import (
 /* No way to teach net or syscall about vsock sockaddr, so go right to C */
 
 /*
+#include <stdio.h>
 #include <sys/socket.h>
 #include "include/uapi/linux/vm_sockets.h"
 int bind_sockaddr_vm(int fd, const struct sockaddr_vm *sa_vm) {
@@ -26,18 +28,40 @@ int connect_sockaddr_vm(int fd, const struct sockaddr_vm *sa_vm) {
 int accept_vm(int fd, struct sockaddr_vm *sa_vm, socklen_t *sa_vm_len) {
     return accept4(fd, (struct sockaddr *)sa_vm, sa_vm_len, 0);
 }
+
+struct sockaddr_hv {
+	unsigned short shv_family;
+	unsigned short reserved;
+	unsigned char  shv_vm_id[16];
+	unsigned char  shv_service_id[16];
+};
+int bind_sockaddr_hv(int fd, const struct sockaddr_hv *sa_hv) {
+    return bind(fd, (const struct sockaddr*)sa_hv, sizeof(*sa_hv));
+}
+int connect_sockaddr_hv(int fd, const struct sockaddr_hv *sa_hv) {
+    return connect(fd, (const struct sockaddr*)sa_hv, sizeof(*sa_hv));
+}
+int accept_hv(int fd, struct sockaddr_hv *sa_hv, socklen_t *sa_hv_len) {
+    return accept4(fd, (struct sockaddr *)sa_hv, sa_hv_len, 0);
+}
 */
 import "C"
 
+type GUID [16]byte
+
 const (
 	AF_VSOCK      = 40
 	VSOCK_CID_ANY = 4294967295 /* 2^32-1 */
+
+	AF_HYPERV     = 42
+	SHV_PROTO_RAW = 1
 )
 
 var (
 	portstr string
 	sock    string
 	detach  bool
+	SHV_VMID_GUEST = GUID{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
 )
 
 func init() {
@@ -66,11 +90,69 @@ func main() {
 		syscall.Dup2(int(fd), int(os.Stderr.Fd()))
 	}
 
-	port, err := strconv.ParseUint(portstr, 10, 32)
+	if strings.Contains(portstr, "-") {
-	if err != nil {
+		guid, err := guidFromString(portstr)
-		log.Fatalln("Can't convert %s to a uint.", portstr, err)
+		if err != nil {
+			log.Fatalln("Failed to parse GUID", portstr, err)
+		}
+		hvsockListen(guid)
+	} else {
+		port, err := strconv.ParseUint(portstr, 10, 32)
+		if err != nil {
+			log.Fatalln("Can't convert %s to a uint.", portstr, err)
+		}
+		vsockListen(uint(port))
+	}
+}
+
+func hvsockListen(port GUID) {
+	accept_fd, err := syscall.Socket(AF_HYPERV, syscall.SOCK_STREAM, SHV_PROTO_RAW)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	sa := C.struct_sockaddr_hv{}
+	sa.shv_family = AF_HYPERV
+	sa.reserved = 0
+	/* TODO: Turn this into a function */
+	for i := 0; i < 16; i++ {
+		sa.shv_vm_id[i] = C.uchar(SHV_VMID_GUEST[i])
+	}
+	for i := 0; i < 16; i++ {
+		sa.shv_service_id[i] = C.uchar(port[i])
+	}
+
+	if ret := C.bind_sockaddr_hv(C.int(accept_fd), &sa); ret != 0 {
+		log.Fatal(fmt.Sprintf("failed bind hvsock connection to %s.%s, returned %d",
+			SHV_VMID_GUEST.toString(), port.toString(), ret))
+	}
+
+	err = syscall.Listen(accept_fd, syscall.SOMAXCONN)
+	if err != nil {
+		log.Fatalln("Failed to listen to VSOCK", err)
+	}
+
+	log.Printf("Listening on fd %d", accept_fd)
+
+	connid := 0
+
+	for {
+		var accept_sa C.struct_sockaddr_hv
+		var accept_sa_len C.socklen_t
+
+		connid++
+		accept_sa_len = C.sizeof_struct_sockaddr_hv
+		fd, err := C.accept_hv(C.int(accept_fd), &accept_sa, &accept_sa_len)
+		if err != nil {
+			log.Fatalln("Error accepting connection", err)
+		}
+
+		accept_vm_id := guidFromC(accept_sa.shv_vm_id)
+		accept_svc_id := guidFromC(accept_sa.shv_service_id)
+		log.Printf("%d Accepted connection on fd %d from %s.%s",
+			connid, fd, accept_vm_id.toString(), accept_svc_id.toString())
+		go handleOne(connid, int(fd))
 	}
-	vsockListen(uint(port))
 }
 
 func vsockListen(port uint) {
@@ -186,3 +268,33 @@ func handleOne(connid int, fd int) {
 	totalWritten := <-w
 	log.Println(connid, "Done. read:", totalRead, "written:", totalWritten)
 }
+
+func (g *GUID) toString() string {
+	/* XXX This assume little endian */
+	return fmt.Sprintf("%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+		g[3], g[2], g[1], g[0],
+		g[5], g[4],
+		g[7], g[6],
+		g[8], g[9],
+		g[10], g[11], g[12], g[13], g[14], g[15])
+}
+
+func guidFromString(s string) (GUID, error) {
+	var g GUID
+	var err error
+	_, err = fmt.Sscanf(s, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+		&g[3], &g[2], &g[1], &g[0],
+		&g[5], &g[4],
+		&g[7], &g[6],
+		&g[8], &g[9],
+		&g[10], &g[11], &g[12], &g[13], &g[14], &g[15])
+	return g, err
+}
+
+func guidFromC(cg [16]C.uchar) GUID {
+       var g GUID
+       for i := 0; i < 16; i++ {
+               g[i] = byte(cg[i])
+       }
+       return g
+}