[Libguestfs] [PATCH libnbd 2/2] api: Add support for AF_VSOCK.
Richard W.M. Jones
rjones at redhat.com
Fri Oct 18 15:39:13 UTC 2019
This adds a new API for connecting to AF_VSOCK protocol
(https://wiki.qemu.org/Features/VirtioVsock).
For example:
nbd_connect_vsock (nbd, 2, 10809);
There is no test of this feature because it only works between guest
and host. You cannot start a server and client on the host and talk
between them, which is what we'd need to write a sane test.
---
configure.ac | 2 ++
fuse/nbdfuse.c | 26 +++++++++++++++++++
fuse/nbdfuse.pod | 8 ++++++
generator/generator | 51 ++++++++++++++++++++++++++++++++++++--
generator/states-connect.c | 22 ++++++++++++++++
lib/connect.c | 20 +++++++++++++++
lib/internal.h | 3 +++
7 files changed, 130 insertions(+), 2 deletions(-)
diff --git a/configure.ac b/configure.ac
index a84580d..95ffca7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -77,6 +77,8 @@ AC_CHECK_HEADERS([\
stdatomic.h \
sys/endian.h])
+AC_CHECK_HEADERS([linux/vm_sockets.h], [], [], [#include <sys/socket.h>])
+
dnl Check for functions, all optional.
AC_CHECK_FUNCS([\
execvpe])
diff --git a/fuse/nbdfuse.c b/fuse/nbdfuse.c
index 75bb0be..c0aee79 100644
--- a/fuse/nbdfuse.c
+++ b/fuse/nbdfuse.c
@@ -24,6 +24,7 @@
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
+#include <inttypes.h>
#include <string.h>
#include <getopt.h>
#include <limits.h>
@@ -97,6 +98,7 @@ usage (FILE *fp, int exitcode)
" nbdfuse MOUNTPOINT[/FILENAME] --fd N\n"
" nbdfuse MOUNTPOINT[/FILENAME] --tcp HOST PORT\n"
" nbdfuse MOUNTPOINT[/FILENAME] --unix SOCKET\n"
+" nbdfuse MOUNTPOINT[/FILENAME] --vsock CID PORT\n"
"\n"
"Please read the nbdfuse(1) manual page for full usage.\n"
"\n"
@@ -139,6 +141,7 @@ main (int argc, char *argv[])
MODE_SOCKET_ACTIVATION,
MODE_TCP,
MODE_UNIX,
+ MODE_VSOCK,
} mode = MODE_URI;
enum {
HELP_OPTION = CHAR_MAX + 1,
@@ -161,6 +164,7 @@ main (int argc, char *argv[])
{ NULL }
};
int c, fd, r;
+ uint32_t cid, port;
int64_t ssize;
const char *s;
struct fuse_args fuse_args = FUSE_ARGS_INIT (0, NULL);
@@ -262,6 +266,10 @@ main (int argc, char *argv[])
mode = MODE_UNIX;
optind++;
}
+ else if (strcmp (argv[optind], "--vsock") == 0) {
+ mode = MODE_VSOCK;
+ optind++;
+ }
/* This is undocumented, but allow either URI or --uri URI. */
else if (strcmp (argv[optind], "--uri") == 0) {
mode = MODE_URI;
@@ -289,6 +297,7 @@ main (int argc, char *argv[])
usage (stderr, EXIT_FAILURE);
break;
case MODE_TCP:
+ case MODE_VSOCK:
if (argc - optind != 2)
usage (stderr, EXIT_FAILURE);
break;
@@ -357,6 +366,23 @@ main (int argc, char *argv[])
exit (EXIT_FAILURE);
}
break;
+
+ case MODE_VSOCK:
+ if (sscanf (argv[optind], "%" SCNu32, &cid) != 1) {
+ fprintf (stderr, "%s: could not parse vsock cid: %s\n\n",
+ argv[0], argv[optind]);
+ exit (EXIT_FAILURE);
+ }
+ if (sscanf (argv[optind+1], "%" SCNu32, &port) != 1) {
+ fprintf (stderr, "%s: could not parse vsock port: %s\n\n",
+ argv[0], argv[optind]);
+ exit (EXIT_FAILURE);
+ }
+ if (nbd_connect_vsock (nbd, cid, port) == -1) {
+ fprintf (stderr, "%s\n", nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
+ break;
}
ssize = nbd_get_size (nbd);
diff --git a/fuse/nbdfuse.pod b/fuse/nbdfuse.pod
index 3187822..3a7401c 100644
--- a/fuse/nbdfuse.pod
+++ b/fuse/nbdfuse.pod
@@ -19,6 +19,8 @@ Other modes:
nbdfuse MOUNTPOINT[/FILENAME] --unix SOCKET
+ nbdfuse MOUNTPOINT[/FILENAME] --vsock CID PORT
+
=head1 DESCRIPTION
nbdfuse presents a Network Block Device as a local file inside a FUSE
@@ -230,6 +232,11 @@ unencrypted TCP socket. See also L<nbd_connect_tcp(3)>.
Select Unix mode. Connect to an NBD server on a Unix domain socket.
See also L<nbd_connect_unix(3)>.
+=item B<--vsock> CID PORT
+
+Select vsock mode. Connect to an NBD server on a C<AF_VSOCK> socket.
+See also L<nbd_connect_vsock(3)>.
+
=back
=head1 NOTES
@@ -294,6 +301,7 @@ L<nbd_connect_socket(3)>,
L<nbd_connect_systemd_socket_activation(3)>,
L<nbd_connect_tcp(3)>,
L<nbd_connect_unix(3)>,
+L<nbd_connect_vsock(3)>,
L<libguestfs(3)>,
L<guestfish(1)>,
L<guestmount(1)>,
diff --git a/generator/generator b/generator/generator
index 54a8eb7..89dd52a 100755
--- a/generator/generator
+++ b/generator/generator
@@ -93,6 +93,7 @@ type external_event =
| CmdCreate (* [nbd_create] function called *)
| CmdConnectSockAddr (* [nbd_aio_connect] function called *)
| CmdConnectUnix (* [nbd_aio_connect_unix] *)
+ | CmdConnectVSock (* [nbd_aio_connect_vsock] *)
| CmdConnectTCP (* [nbd_aio_connect_tcp] *)
| CmdConnectCommand (* [nbd_aio_connect_command] *)
| CmdConnectSA (* [nbd_aio_connect_systemd_socket_activation]*)
@@ -169,6 +170,7 @@ let rec state_machine = [
external_events = [ CmdCreate, "";
CmdConnectSockAddr, "CONNECT.START";
CmdConnectUnix, "CONNECT_UNIX.START";
+ CmdConnectVSock, "CONNECT_VSOCK.START";
CmdConnectTCP, "CONNECT_TCP.START";
CmdConnectCommand, "CONNECT_COMMAND.START";
CmdConnectSA, "CONNECT_SA.START";
@@ -177,6 +179,7 @@ let rec state_machine = [
Group ("CONNECT", connect_state_machine);
Group ("CONNECT_UNIX", connect_unix_state_machine);
+ Group ("CONNECT_VSOCK", connect_vsock_state_machine);
Group ("CONNECT_TCP", connect_tcp_state_machine);
Group ("CONNECT_COMMAND", connect_command_state_machine);
Group ("CONNECT_SA", connect_sa_state_machine);
@@ -236,6 +239,16 @@ and connect_unix_state_machine = [
};
]
+(* State machine implementing [nbd_aio_connect_vsock]. *)
+and connect_vsock_state_machine = [
+ State {
+ default_state with
+ name = "START";
+ comment = "Connect to an AF_VSOCK socket";
+ external_events = [];
+ };
+]
+
(* State machine implementing [nbd_aio_connect_tcp]. *)
and connect_tcp_state_machine = [
State {
@@ -1491,6 +1504,20 @@ when the connection has been made.";
example = Some "examples/fetch-first-sector.c";
};
+ "connect_vsock", {
+ default_call with
+ args = [ UInt32 "cid"; UInt32 "port" ]; ret = RErr;
+ permitted_states = [ Created ];
+ shortdesc = "connect to NBD server over AF_VSOCK protocol";
+ longdesc = "\
+Connect (synchronously) over the C<AF_VSOCK> protocol from a
+virtual machine to an NBD server, usually running on the host. The
+C<cid> and C<port> parameters specify the server address. Usually
+C<cid> should be C<2> (to connect to the host), and C<port> might be
+C<10809> or another port number assigned to you by the host
+administrator. This call returns when the connection has been made.";
+ };
+
"connect_tcp", {
default_call with
args = [ String "hostname"; String "port" ]; ret = RErr;
@@ -2148,6 +2175,22 @@ on the connection.";
example = Some "examples/aio-connect-read.c";
};
+ "aio_connect_vsock", {
+ default_call with
+ args = [ UInt32 "cid"; UInt32 "port" ]; ret = RErr;
+ permitted_states = [ Created ];
+ shortdesc = "connect to the NBD server over AF_VSOCK socket";
+ longdesc = "\
+Begin connecting to the NBD server over the C<AF_VSOCK>
+protocol to the server C<cid:port>. Parameters behave as documented in
+L<nbd_connect_vsock(3)>.
+
+You can check if the connection is still connecting by calling
+L<nbd_aio_is_connecting(3)>, or if it has connected to the server
+and completed the NBD handshake by calling L<nbd_aio_is_ready(3)>,
+on the connection.";
+ };
+
"aio_connect_tcp", {
default_call with
args = [ String "hostname"; String "port" ]; ret = RErr;
@@ -2793,6 +2836,8 @@ let first_version = [
"aio_connect_systemd_socket_activation", (1, 2);
"connect_socket", (1, 2);
"aio_connect_socket", (1, 2);
+ "connect_vsock", (1, 2);
+ "aio_connect_vsock", (1, 2);
(* These calls are proposed for a future version of libnbd, but
* have not been added to any released version so far.
@@ -3151,7 +3196,7 @@ end = struct
let all_external_events =
[NotifyRead; NotifyWrite;
CmdCreate;
- CmdConnectSockAddr; CmdConnectUnix; CmdConnectTCP;
+ CmdConnectSockAddr; CmdConnectUnix; CmdConnectVSock; CmdConnectTCP;
CmdConnectCommand; CmdConnectSA; CmdConnectSocket;
CmdIssue]
@@ -3161,6 +3206,7 @@ let string_of_external_event = function
| CmdCreate -> "CmdCreate"
| CmdConnectSockAddr -> "CmdConnectSockAddr"
| CmdConnectUnix -> "CmdConnectUnix"
+ | CmdConnectVSock -> "CmdConnectVSock"
| CmdConnectTCP -> "CmdConnectTCP"
| CmdConnectCommand -> "CmdConnectCommand"
| CmdConnectSA -> "CmdConnectSA"
@@ -3173,6 +3219,7 @@ let c_string_of_external_event = function
| CmdCreate -> "cmd_create"
| CmdConnectSockAddr -> "cmd_connect_sockaddr"
| CmdConnectUnix -> "cmd_connect_unix"
+ | CmdConnectVSock -> "cmd_connect_vsock"
| CmdConnectTCP -> "cmd_connect_tcp"
| CmdConnectCommand -> "cmd_connect_command"
| CmdConnectSA -> "cmd_connect_sa"
@@ -3624,7 +3671,7 @@ let generate_lib_states_run_c () =
| NotifyWrite -> pr " r |= LIBNBD_AIO_DIRECTION_WRITE;\n"
| CmdCreate
| CmdConnectSockAddr
- | CmdConnectUnix | CmdConnectTCP
+ | CmdConnectUnix | CmdConnectVSock | CmdConnectTCP
| CmdConnectCommand | CmdConnectSA | CmdConnectSocket
| CmdIssue -> ()
) events;
diff --git a/generator/states-connect.c b/generator/states-connect.c
index d62b0f5..e4658a7 100644
--- a/generator/states-connect.c
+++ b/generator/states-connect.c
@@ -37,6 +37,10 @@
#include <sys/socket.h>
#include <sys/un.h>
+#ifdef HAVE_LINUX_VM_SOCKETS_H
+#include <linux/vm_sockets.h>
+#endif
+
/* Disable Nagle's algorithm on the socket, but don't fail. */
static void
disable_nagle (int sock)
@@ -118,6 +122,24 @@ STATE_MACHINE {
SET_NEXT_STATE (%^CONNECT.START);
return 0;
+ CONNECT_VSOCK.START:
+#ifdef AF_VSOCK
+ struct sockaddr_vm svm = {
+ .svm_family = AF_VSOCK,
+ .svm_cid = h->svm_cid,
+ .svm_port = h->svm_port,
+ };
+ const socklen_t len = sizeof svm;
+
+ memcpy (&h->connaddr, &svm, len);
+ h->connaddrlen = len;
+ SET_NEXT_STATE (%^CONNECT.START);
+ return 0;
+#else
+ set_error (ENOTSUP, "AF_VSOCK protocol is not supported");
+ SET_NEXT_STATE (%.DEAD);
+#endif
+
CONNECT_TCP.START:
int r;
diff --git a/lib/connect.c b/lib/connect.c
index a0ef5f1..d8bb121 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -92,6 +92,16 @@ nbd_unlocked_connect_unix (struct nbd_handle *h, const char *unixsocket)
return wait_until_connected (h);
}
+/* Connect to a vsock. */
+int
+nbd_unlocked_connect_vsock (struct nbd_handle *h, uint32_t cid, uint32_t port)
+{
+ if (nbd_unlocked_aio_connect_vsock (h, cid, port) == -1)
+ return -1;
+
+ return wait_until_connected (h);
+}
+
/* Connect to a TCP port. */
int
nbd_unlocked_connect_tcp (struct nbd_handle *h,
@@ -388,6 +398,16 @@ nbd_unlocked_aio_connect_unix (struct nbd_handle *h, const char *unixsocket)
return nbd_internal_run (h, cmd_connect_unix);
}
+int
+nbd_unlocked_aio_connect_vsock (struct nbd_handle *h,
+ uint32_t cid, uint32_t port)
+{
+ h->svm_cid = cid;
+ h->svm_port = port;
+
+ return nbd_internal_run (h, cmd_connect_vsock);
+}
+
int
nbd_unlocked_aio_connect_tcp (struct nbd_handle *h,
const char *hostname, const char *port)
diff --git a/lib/internal.h b/lib/internal.h
index 6433183..ba053c2 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -197,6 +197,9 @@ struct nbd_handle {
/* When connecting to Unix domain socket. */
char *unixsocket;
+ /* When connecting to a vsock. */
+ uint32_t svm_cid, svm_port;
+
/* When connecting to TCP ports, these fields are used. */
char *hostname, *port;
struct addrinfo hints;
--
2.23.0
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