Merge pull request #94 from djs55/diagnostics-vsock

diagnostics: bind also on a vsock port

alpine/packages/diagnostics/main.go

@@ -10,6 +10,7 @@ import (
 	"path"
 	"strings"
 	"time"
+	"github.com/djs55/vsock"
 )
 
 func run(timeout time.Duration, w *tar.Writer, command string, args ...string) {
@@ -108,6 +109,12 @@ func main() {
 	} else {
 		listeners = append(listeners, ip)
 	}
+	vsock, err := vsock.Listen(uint(62374))
+	if err != nil {
+		log.Printf("Failed to bind to vsock port 62374: %#v", err)
+	} else {
+		listeners = append(listeners, vsock)
+	}
 
 	for _, l := range listeners {
 		go func(l net.Listener) {

alpine/packages/diagnostics/vendor/github.com/djs55/vsock/vsock.go

@@ -0,0 +1,171 @@
+package vsock
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"os"
+	"syscall"
+	"time"
+)
+
+/* No way to teach net or syscall about vsock sockaddr, so go right to C */
+
+/*
+#include <sys/socket.h>
+
+struct sockaddr_vm {
+	sa_family_t svm_family;
+	unsigned short svm_reserved1;
+	unsigned int svm_port;
+	unsigned int svm_cid;
+	unsigned char svm_zero[sizeof(struct sockaddr) -
+		sizeof(sa_family_t) - sizeof(unsigned short) -
+		sizeof(unsigned int) - sizeof(unsigned int)];
+};
+
+int bind_sockaddr_vm(int fd, const struct sockaddr_vm *sa_vm) {
+    return bind(fd, (const struct sockaddr*)sa_vm, sizeof(*sa_vm));
+}
+int connect_sockaddr_vm(int fd, const struct sockaddr_vm *sa_vm) {
+    return connect(fd, (const struct sockaddr*)sa_vm, sizeof(*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);
+}
+*/
+import "C"
+
+const (
+	AF_VSOCK       = 40
+	VSOCK_CID_ANY  = 4294967295 /* 2^32-1 */
+	VSOCK_CID_SELF = 3
+)
+
+// Listen returns a net.Listener which can accept connections on the given
+// vhan port.
+func Listen(port uint) (net.Listener, error) {
+	accept_fd, err := syscall.Socket(AF_VSOCK, syscall.SOCK_STREAM, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	sa := C.struct_sockaddr_vm{}
+	sa.svm_family = AF_VSOCK
+	sa.svm_port = C.uint(port)
+	sa.svm_cid = VSOCK_CID_ANY
+
+	if ret := C.bind_sockaddr_vm(C.int(accept_fd), &sa); ret != 0 {
+		return nil, errors.New(fmt.Sprintf("failed bind vsock connection to %08x.%08x, returned %d", sa.svm_cid, sa.svm_port, ret))
+	}
+
+	err = syscall.Listen(accept_fd, syscall.SOMAXCONN)
+	if err != nil {
+		return nil, err
+	}
+	return &vsockListener{accept_fd, port}, nil
+}
+
+// Conn is a vsock connection which support half-close.
+type Conn interface {
+	net.Conn
+	CloseRead() error
+	CloseWrite() error
+}
+
+type vsockListener struct {
+	accept_fd int
+	port      uint
+}
+
+func (v *vsockListener) Accept() (net.Conn, error) {
+	var accept_sa C.struct_sockaddr_vm
+	var accept_sa_len C.socklen_t
+
+	accept_sa_len = C.sizeof_struct_sockaddr_vm
+	fd, err := C.accept_vm(C.int(v.accept_fd), &accept_sa, &accept_sa_len)
+	if err != nil {
+		return nil, err
+	}
+	return newVsockConn(uintptr(fd), v.port)
+}
+
+func (v *vsockListener) Close() error {
+	// Note this won't cause the Accept to unblock.
+	return syscall.Close(v.accept_fd)
+}
+
+type VsockAddr struct {
+	Port uint
+}
+
+func (a VsockAddr) Network() string {
+	return "vsock"
+}
+
+func (a VsockAddr) String() string {
+	return fmt.Sprintf("%08x", a.Port)
+}
+
+func (v *vsockListener) Addr() net.Addr {
+	return VsockAddr{Port: v.port}
+}
+
+// a wrapper around FileConn which supports CloseRead and CloseWrite
+type vsockConn struct {
+	vsock  *os.File
+	fd     uintptr
+	local  VsockAddr
+	remote VsockAddr
+}
+
+type VsockConn struct {
+	vsockConn
+}
+
+func newVsockConn(fd uintptr, localPort uint) (*VsockConn, error) {
+	vsock := os.NewFile(fd, fmt.Sprintf("vsock:%d", fd))
+	local := VsockAddr{Port: localPort}
+	remote := VsockAddr{Port: uint(0)} // FIXME
+	return &VsockConn{vsockConn{vsock: vsock, fd: fd, local: local, remote: remote}}, nil
+}
+
+func (v *VsockConn) LocalAddr() net.Addr {
+	return v.local
+}
+
+func (v *VsockConn) RemoteAddr() net.Addr {
+	return v.remote
+}
+
+func (v *VsockConn) CloseRead() error {
+	return syscall.Shutdown(int(v.fd), syscall.SHUT_RD)
+}
+
+func (v *VsockConn) CloseWrite() error {
+	return syscall.Shutdown(int(v.fd), syscall.SHUT_WR)
+}
+
+func (v *VsockConn) Close() error {
+	return v.vsock.Close()
+}
+
+func (v *VsockConn) Read(buf []byte) (int, error) {
+	return v.vsock.Read(buf)
+}
+
+func (v *VsockConn) Write(buf []byte) (int, error) {
+	return v.vsock.Write(buf)
+}
+
+func (v *VsockConn) SetDeadline(t time.Time) error {
+	return nil // FIXME
+}
+
+func (v *VsockConn) SetReadDeadline(t time.Time) error {
+	return nil // FIXME
+}
+
+func (v *VsockConn) SetWriteDeadline(t time.Time) error {
+	return nil // FIXME
+}

alpine/packages/diagnostics/vendor/manifest

@@ -0,0 +1,13 @@
+{
+	"version": 0,
+	"dependencies": [
+		{
+			"importpath": "github.com/djs55/vsock",
+			"repository": "ssh://github.com/djs55/vsock",
+			"vcs": "git",
+			"revision": "7ea787de194e9a251ea746cf37f464c1e6cb822a",
+			"branch": "master",
+			"notests": true
+		}
+	]
+}