diff mbox series

[v9,08/16] net: stream: add unix socket

Message ID 20220926195048.487915-9-lvivier@redhat.com (mailing list archive)
State New, archived
Headers show
Series qapi: net: add unix socket type support to netdev backend | expand

Commit Message

Laurent Vivier Sept. 26, 2022, 7:50 p.m. UTC 
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
---
 net/stream.c    | 108 +++++++++++++++++++++++++++++++++++++++++++++---
 qapi/net.json   |   2 +-
 qemu-options.hx |   1 +
 3 files changed, 105 insertions(+), 6 deletions(-)

Comments

David Gibson Sept. 28, 2022, 6:12 a.m. UTC | #1 
On Mon, Sep 26, 2022 at 09:50:40PM +0200, Laurent Vivier wrote:
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
> ---
>  net/stream.c    | 108 +++++++++++++++++++++++++++++++++++++++++++++---
>  qapi/net.json   |   2 +-
>  qemu-options.hx |   1 +
>  3 files changed, 105 insertions(+), 6 deletions(-)
> 
> diff --git a/net/stream.c b/net/stream.c
> index 3fb899df5d2d..02967c284efc 100644
> --- a/net/stream.c
> +++ b/net/stream.c
> @@ -235,7 +235,7 @@ static NetStreamState *net_stream_fd_init_stream(NetClientState *peer,
>  static void net_stream_accept(void *opaque)
>  {
>      NetStreamState *s = opaque;
> -    struct sockaddr_in saddr;
> +    struct sockaddr_storage saddr;
>      socklen_t len;
>      int fd;
>  
> @@ -253,9 +253,27 @@ static void net_stream_accept(void *opaque)
>      s->fd = fd;
>      s->nc.link_down = false;
>      net_stream_connect(s);
> -    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
> -             "connection from %s:%d",
> -             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
> +    switch (saddr.ss_family) {
> +    case AF_INET: {
> +        struct sockaddr_in *saddr_in = (struct sockaddr_in *)&saddr;
> +
> +        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
> +                 "connection from %s:%d",
> +                 inet_ntoa(saddr_in->sin_addr), ntohs(saddr_in->sin_port));

So, here you print the address from which the connection has come -
the remote address.

> +        break;
> +    }
> +    case AF_UNIX: {
> +        struct sockaddr_un saddr_un;
> +
> +        len = sizeof(saddr_un);
> +        getsockname(s->listen_fd, (struct sockaddr *)&saddr_un, &len);
> +        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
> +                 "connect from %s", saddr_un.sun_path);

Here you print the bound address - the local address.  Does that make
sense?  I mean, in almost every occasion the remote Unix socket will
be anonymous, so it probably doesn't make sense to display that, but
is the bound address actually a useful substitute?

Maybe it should just be "connect from Unix socket".

> +        break;
> +    }
> +    default:
> +        g_assert_not_reached();
> +    }
>  }
>  
>  static int net_stream_server_init(NetClientState *peer,
> @@ -295,6 +313,43 @@ static int net_stream_server_init(NetClientState *peer,
>          }
>          break;
>      }
> +    case SOCKET_ADDRESS_TYPE_UNIX: {
> +        struct sockaddr_un saddr_un;
> +
> +        ret = unlink(addr->u.q_unix.path);
> +        if (ret < 0 && errno != ENOENT) {
> +            error_setg_errno(errp, errno, "failed to unlink socket %s",
> +                             addr->u.q_unix.path);
> +            return -1;
> +        }
> +
> +        saddr_un.sun_family = PF_UNIX;
> +        ret = snprintf(saddr_un.sun_path, sizeof(saddr_un.sun_path), "%s",
> +                       addr->u.q_unix.path);
> +        if (ret < 0 || ret >= sizeof(saddr_un.sun_path)) {
> +            error_setg(errp, "UNIX socket path '%s' is too long",
> +                       addr->u.q_unix.path);
> +            error_append_hint(errp, "Path must be less than %zu bytes\n",
> +                              sizeof(saddr_un.sun_path));
> +            return -1;
> +        }

Not necessarily in scope here, but I do wonder if we want a common
helper to convert the QAPI SocketAddress to a struct sockaddr, which
supports both inet and Unix - and one day IPv6, one hopes - with all
the appropriate error handling.

> +
> +        fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
> +        if (fd < 0) {
> +            error_setg_errno(errp, errno, "can't create stream socket");
> +            return -1;
> +        }
> +        qemu_socket_set_nonblock(fd);
> +
> +        ret = bind(fd, (struct sockaddr *)&saddr_un, sizeof(saddr_un));
> +        if (ret < 0) {
> +            error_setg_errno(errp, errno, "can't create socket with path: %s",
> +                             saddr_un.sun_path);
> +            closesocket(fd);
> +            return -1;
> +        }
> +        break;
> +    }
>      case SOCKET_ADDRESS_TYPE_FD:
>          fd = monitor_fd_param(monitor_cur(), addr->u.fd.str, errp);
>          if (fd == -1) {
> @@ -380,6 +435,49 @@ static int net_stream_client_init(NetClientState *peer,
>                                     ntohs(saddr_in.sin_port));
>          break;
>      }
> +    case SOCKET_ADDRESS_TYPE_UNIX: {
> +        struct sockaddr_un saddr_un;
> +
> +        saddr_un.sun_family = PF_UNIX;
> +        ret = snprintf(saddr_un.sun_path, sizeof(saddr_un.sun_path), "%s",
> +                       addr->u.q_unix.path);
> +        if (ret < 0 || ret >= sizeof(saddr_un.sun_path)) {
> +            error_setg(errp, "UNIX socket path '%s' is too long",
> +                       addr->u.q_unix.path);
> +            error_append_hint(errp, "Path must be less than %zu bytes\n",
> +                              sizeof(saddr_un.sun_path));
> +            return -1;
> +        }
> +
> +        fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
> +        if (fd < 0) {
> +            error_setg_errno(errp, errno, "can't create stream socket");
> +            return -1;
> +        }
> +        qemu_socket_set_nonblock(fd);
> +
> +        connected = 0;
> +        for (;;) {
> +            ret = connect(fd, (struct sockaddr *)&saddr_un, sizeof(saddr_un));
> +            if (ret < 0) {
> +                if (errno == EINTR || errno == EWOULDBLOCK) {
> +                    /* continue */
> +                } else if (errno == EAGAIN ||
> +                           errno == EALREADY) {
> +                    break;
> +                } else {
> +                    error_setg_errno(errp, errno, "can't connect socket");
> +                    closesocket(fd);
> +                    return -1;
> +                }
> +            } else {
> +                connected = 1;
> +                break;
> +            }
> +        }
> +        info_str = g_strdup_printf(" connect to %s", saddr_un.sun_path);
> +        break;
> +    }
>      case SOCKET_ADDRESS_TYPE_FD:
>          fd = monitor_fd_param(monitor_cur(), addr->u.fd.str, errp);
>          if (fd == -1) {
> @@ -395,7 +493,7 @@ static int net_stream_client_init(NetClientState *peer,
>          info_str = g_strdup_printf("connect to fd %d", fd);
>          break;
>      default:
> -        error_setg(errp, "only support inet or fd type");
> +        error_setg(errp, "only support inet, unix or fd type");
>          return -1;
>      }
>  
> diff --git a/qapi/net.json b/qapi/net.json
> index e02e8001a000..bb96701a49a7 100644
> --- a/qapi/net.json
> +++ b/qapi/net.json
> @@ -583,7 +583,7 @@
>  #        or connect to (server=false)
>  # @server: create server socket (default: true)
>  #
> -# Only SocketAddress types 'inet' and 'fd' are supported.
> +# Only SocketAddress types 'unix', 'inet' and 'fd' are supported.
>  #
>  # Since: 7.1
>  ##
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 8c765f345da8..7a34022ac651 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2735,6 +2735,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
>      "                configure a network backend to connect to another network\n"
>      "                using an UDP tunnel\n"
>      "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port\n"
> +    "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path\n"
>      "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=h\n"
>      "                configure a network backend to connect to another network\n"
>      "                using a socket connection in stream mode.\n"
Laurent Vivier Oct. 5, 2022, 1:38 p.m. UTC | #2 
On 9/28/22 08:12, David Gibson wrote:
>> @@ -253,9 +253,27 @@ static void net_stream_accept(void *opaque)
>>       s->fd = fd;
>>       s->nc.link_down = false;
>>       net_stream_connect(s);
>> -    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
>> -             "connection from %s:%d",
>> -             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
>> +    switch (saddr.ss_family) {
>> +    case AF_INET: {
>> +        struct sockaddr_in *saddr_in = (struct sockaddr_in *)&saddr;
>> +
>> +        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
>> +                 "connection from %s:%d",
>> +                 inet_ntoa(saddr_in->sin_addr), ntohs(saddr_in->sin_port));
> So, here you print the address from which the connection has come -
> the remote address.
> 
>> +        break;
>> +    }
>> +    case AF_UNIX: {
>> +        struct sockaddr_un saddr_un;
>> +
>> +        len = sizeof(saddr_un);
>> +        getsockname(s->listen_fd, (struct sockaddr *)&saddr_un, &len);
>> +        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
>> +                 "connect from %s", saddr_un.sun_path);
> Here you print the bound address - the local address.  Does that make
> sense?  I mean, in almost every occasion the remote Unix socket will
> be anonymous, so it probably doesn't make sense to display that, but
> is the bound address actually a useful substitute?
> 
> Maybe it should just be "connect from Unix socket".
> 

I agree the needed information is "connected" and type "unix".

But I think more information we can put here can be useful for a debugging purpose.

Thanks,
Laurent
David Gibson Oct. 6, 2022, 12:39 a.m. UTC | #3 
On Wed, Oct 05, 2022 at 03:38:09PM +0200, Laurent Vivier wrote:
> On 9/28/22 08:12, David Gibson wrote:
> > > @@ -253,9 +253,27 @@ static void net_stream_accept(void *opaque)
> > >       s->fd = fd;
> > >       s->nc.link_down = false;
> > >       net_stream_connect(s);
> > > -    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
> > > -             "connection from %s:%d",
> > > -             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
> > > +    switch (saddr.ss_family) {
> > > +    case AF_INET: {
> > > +        struct sockaddr_in *saddr_in = (struct sockaddr_in *)&saddr;
> > > +
> > > +        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
> > > +                 "connection from %s:%d",
> > > +                 inet_ntoa(saddr_in->sin_addr), ntohs(saddr_in->sin_port));
> > So, here you print the address from which the connection has come -
> > the remote address.
> > 
> > > +        break;
> > > +    }
> > > +    case AF_UNIX: {
> > > +        struct sockaddr_un saddr_un;
> > > +
> > > +        len = sizeof(saddr_un);
> > > +        getsockname(s->listen_fd, (struct sockaddr *)&saddr_un, &len);
> > > +        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
> > > +                 "connect from %s", saddr_un.sun_path);
> > Here you print the bound address - the local address.  Does that make
> > sense?  I mean, in almost every occasion the remote Unix socket will
> > be anonymous, so it probably doesn't make sense to display that, but
> > is the bound address actually a useful substitute?
> > 
> > Maybe it should just be "connect from Unix socket".
> > 
> 
> I agree the needed information is "connected" and type "unix".
> 
> But I think more information we can put here can be useful for a debugging purpose.

Fair enough.  I feel like "connect from" is still possible
misleading.  Maybe "connect via"?  Or even "connection to Unix socket %s"?
diff mbox series

Patch

diff --git a/net/stream.c b/net/stream.c
index 3fb899df5d2d..02967c284efc 100644
--- a/net/stream.c
+++ b/net/stream.c
@@ -235,7 +235,7 @@  static NetStreamState *net_stream_fd_init_stream(NetClientState *peer,
 static void net_stream_accept(void *opaque)
 {
     NetStreamState *s = opaque;
-    struct sockaddr_in saddr;
+    struct sockaddr_storage saddr;
     socklen_t len;
     int fd;
 
@@ -253,9 +253,27 @@  static void net_stream_accept(void *opaque)
     s->fd = fd;
     s->nc.link_down = false;
     net_stream_connect(s);
-    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
-             "connection from %s:%d",
-             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+    switch (saddr.ss_family) {
+    case AF_INET: {
+        struct sockaddr_in *saddr_in = (struct sockaddr_in *)&saddr;
+
+        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
+                 "connection from %s:%d",
+                 inet_ntoa(saddr_in->sin_addr), ntohs(saddr_in->sin_port));
+        break;
+    }
+    case AF_UNIX: {
+        struct sockaddr_un saddr_un;
+
+        len = sizeof(saddr_un);
+        getsockname(s->listen_fd, (struct sockaddr *)&saddr_un, &len);
+        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
+                 "connect from %s", saddr_un.sun_path);
+        break;
+    }
+    default:
+        g_assert_not_reached();
+    }
 }
 
 static int net_stream_server_init(NetClientState *peer,
@@ -295,6 +313,43 @@  static int net_stream_server_init(NetClientState *peer,
         }
         break;
     }
+    case SOCKET_ADDRESS_TYPE_UNIX: {
+        struct sockaddr_un saddr_un;
+
+        ret = unlink(addr->u.q_unix.path);
+        if (ret < 0 && errno != ENOENT) {
+            error_setg_errno(errp, errno, "failed to unlink socket %s",
+                             addr->u.q_unix.path);
+            return -1;
+        }
+
+        saddr_un.sun_family = PF_UNIX;
+        ret = snprintf(saddr_un.sun_path, sizeof(saddr_un.sun_path), "%s",
+                       addr->u.q_unix.path);
+        if (ret < 0 || ret >= sizeof(saddr_un.sun_path)) {
+            error_setg(errp, "UNIX socket path '%s' is too long",
+                       addr->u.q_unix.path);
+            error_append_hint(errp, "Path must be less than %zu bytes\n",
+                              sizeof(saddr_un.sun_path));
+            return -1;
+        }
+
+        fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
+        if (fd < 0) {
+            error_setg_errno(errp, errno, "can't create stream socket");
+            return -1;
+        }
+        qemu_socket_set_nonblock(fd);
+
+        ret = bind(fd, (struct sockaddr *)&saddr_un, sizeof(saddr_un));
+        if (ret < 0) {
+            error_setg_errno(errp, errno, "can't create socket with path: %s",
+                             saddr_un.sun_path);
+            closesocket(fd);
+            return -1;
+        }
+        break;
+    }
     case SOCKET_ADDRESS_TYPE_FD:
         fd = monitor_fd_param(monitor_cur(), addr->u.fd.str, errp);
         if (fd == -1) {
@@ -380,6 +435,49 @@  static int net_stream_client_init(NetClientState *peer,
                                    ntohs(saddr_in.sin_port));
         break;
     }
+    case SOCKET_ADDRESS_TYPE_UNIX: {
+        struct sockaddr_un saddr_un;
+
+        saddr_un.sun_family = PF_UNIX;
+        ret = snprintf(saddr_un.sun_path, sizeof(saddr_un.sun_path), "%s",
+                       addr->u.q_unix.path);
+        if (ret < 0 || ret >= sizeof(saddr_un.sun_path)) {
+            error_setg(errp, "UNIX socket path '%s' is too long",
+                       addr->u.q_unix.path);
+            error_append_hint(errp, "Path must be less than %zu bytes\n",
+                              sizeof(saddr_un.sun_path));
+            return -1;
+        }
+
+        fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
+        if (fd < 0) {
+            error_setg_errno(errp, errno, "can't create stream socket");
+            return -1;
+        }
+        qemu_socket_set_nonblock(fd);
+
+        connected = 0;
+        for (;;) {
+            ret = connect(fd, (struct sockaddr *)&saddr_un, sizeof(saddr_un));
+            if (ret < 0) {
+                if (errno == EINTR || errno == EWOULDBLOCK) {
+                    /* continue */
+                } else if (errno == EAGAIN ||
+                           errno == EALREADY) {
+                    break;
+                } else {
+                    error_setg_errno(errp, errno, "can't connect socket");
+                    closesocket(fd);
+                    return -1;
+                }
+            } else {
+                connected = 1;
+                break;
+            }
+        }
+        info_str = g_strdup_printf(" connect to %s", saddr_un.sun_path);
+        break;
+    }
     case SOCKET_ADDRESS_TYPE_FD:
         fd = monitor_fd_param(monitor_cur(), addr->u.fd.str, errp);
         if (fd == -1) {
@@ -395,7 +493,7 @@  static int net_stream_client_init(NetClientState *peer,
         info_str = g_strdup_printf("connect to fd %d", fd);
         break;
     default:
-        error_setg(errp, "only support inet or fd type");
+        error_setg(errp, "only support inet, unix or fd type");
         return -1;
     }
 
diff --git a/qapi/net.json b/qapi/net.json
index e02e8001a000..bb96701a49a7 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -583,7 +583,7 @@ 
 #        or connect to (server=false)
 # @server: create server socket (default: true)
 #
-# Only SocketAddress types 'inet' and 'fd' are supported.
+# Only SocketAddress types 'unix', 'inet' and 'fd' are supported.
 #
 # Since: 7.1
 ##
diff --git a/qemu-options.hx b/qemu-options.hx
index 8c765f345da8..7a34022ac651 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2735,6 +2735,7 @@  DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
     "                configure a network backend to connect to another network\n"
     "                using an UDP tunnel\n"
     "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port\n"
+    "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path\n"
     "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=h\n"
     "                configure a network backend to connect to another network\n"
     "                using a socket connection in stream mode.\n"