[RFC PATCH 0/6] qapi: net: add unix socket type support to netdev backend

[RFC PATCH 0/6] qapi: net: add unix socket type support to netdev backend

[Laurent Vivier]

"-netdev socket" only supports inet sockets.

It's not a complex task to add support for unix sockets, but
the socket netdev parameters are not defined to manage well unix
socket parameters.

As discussed in:

  "socket.c added support for unix domain socket datagram transport"
  https://lore.kernel.org/qemu-devel/1C0E1BC5-904F-46B0-8044-68E43E67BE60@gmail.com/

This series adds support of unix socket type using SocketAddress QAPI structure.

A new netdev backend "socket-ng" is added, that is barely a copy of "socket"
backend but it uses the SocketAddress QAPI to provide socket parameters.
And then it also implement unix sockets (TCP and UDP).

Some examples of CLI syntax:

  for TCP:

  -netdev socket-ng,id=socket0,mode=server,addr.type=inet,addr.host=localhost,addr.port=1234
  -netdev socket-ng,id=socket0,mode=client,addr.type=inet,addr.host=localhost,addr.port=1234

  -netdev socket-ng,id=socket0,mode=dgram,\
          local.type=inet,local.host=localhost,local.port=1234,\
          remote.type=inet,remote.host=localhost,remote.port=1235

  for UNIX:

  -netdev socket-ng,id=socket0,mode=server,addr.type=unix,addr.path=/tmp/qemu0
  -netdev socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/qemu0

  -netdev socket-ng,id=socket0,mode=dgram,\
          local.type=unix,local.path=/tmp/qemu0,\
          remote.type=unix,remote.path=/tmp/qemu1

  for FD:

  -netdev socket-ng,id=socket0,mode=server,addr.type=fd,addr.str=4
  -netdev socket-ng,id=socket0,mode=client,addr.type=fd,addr.str=5

  -netdev socket-ng,id=socket0,mode=dgram,local.type=fd,addr.str=4

CC: Ralph Schmieder <ralph.schmieder@gmail.com>
CC: Stefano Brivio <sbrivio@redhat.com>
CC: Daniel P. Berrangé <berrange@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>

Laurent Vivier (6):
  net: introduce convert_host_port()
  qapi: net: add socket-ng netdev
  net: socket-ng: add unix socket for server and client mode.
  net: socket-ng: make dgram_dst generic
  net: socket-ng: move mcast specific code from
    net_socket_fd_init_dgram()
  net: socket-ng: add unix socket for dgram mode

 hmp-commands.hx        |    2 +-
 include/qemu/sockets.h |    2 +
 net/clients.h          |    3 +
 net/hub.c              |    1 +
 net/meson.build        |    1 +
 net/net.c              |  123 +++--
 net/socket-ng.c        | 1060 ++++++++++++++++++++++++++++++++++++++++
 qapi/net.json          |   41 +-
 8 files changed, 1200 insertions(+), 33 deletions(-)
 create mode 100644 net/socket-ng.c

-- 
2.35.3

[RFC PATCH 1/6] net: introduce convert_host_port()

[Laurent Vivier]

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 include/qemu/sockets.h |  2 ++
 net/net.c              | 62 ++++++++++++++++++++++--------------------
 2 files changed, 34 insertions(+), 30 deletions(-)

diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
index 038faa157f59..47194b9732f8 100644
--- a/include/qemu/sockets.h
+++ b/include/qemu/sockets.h
@@ -47,6 +47,8 @@ void socket_listen_cleanup(int fd, Error **errp);
 int socket_dgram(SocketAddress *remote, SocketAddress *local, Error **errp);
 
 /* Old, ipv4 only bits.  Don't use for new code. */
+int convert_host_port(struct sockaddr_in *saddr, const char *host,
+                      const char *port, Error **errp);
 int parse_host_port(struct sockaddr_in *saddr, const char *str,
                     Error **errp);
 int socket_init(void);
diff --git a/net/net.c b/net/net.c
index a094cf1d2929..58c05c200622 100644
--- a/net/net.c
+++ b/net/net.c
@@ -66,55 +66,57 @@ static QTAILQ_HEAD(, NetClientState) net_clients;
 /***********************************************************/
 /* network device redirectors */
 
-int parse_host_port(struct sockaddr_in *saddr, const char *str,
-                    Error **errp)
+int convert_host_port(struct sockaddr_in *saddr, const char *host,
+                      const char *port, Error **errp)
 {
-    gchar **substrings;
     struct hostent *he;
-    const char *addr, *p, *r;
-    int port, ret = 0;
+    const char *r;
+    long p;
 
     memset(saddr, 0, sizeof(*saddr));
 
-    substrings = g_strsplit(str, ":", 2);
-    if (!substrings || !substrings[0] || !substrings[1]) {
-        error_setg(errp, "host address '%s' doesn't contain ':' "
-                   "separating host from port", str);
-        ret = -1;
-        goto out;
-    }
-
-    addr = substrings[0];
-    p = substrings[1];
-
     saddr->sin_family = AF_INET;
-    if (addr[0] == '\0') {
+    if (host[0] == '\0') {
         saddr->sin_addr.s_addr = 0;
     } else {
-        if (qemu_isdigit(addr[0])) {
-            if (!inet_aton(addr, &saddr->sin_addr)) {
+        if (qemu_isdigit(host[0])) {
+            if (!inet_aton(host, &saddr->sin_addr)) {
                 error_setg(errp, "host address '%s' is not a valid "
-                           "IPv4 address", addr);
-                ret = -1;
-                goto out;
+                           "IPv4 address", host);
+                return -1;
             }
         } else {
-            he = gethostbyname(addr);
+            he = gethostbyname(host);
             if (he == NULL) {
-                error_setg(errp, "can't resolve host address '%s'", addr);
-                ret = -1;
-                goto out;
+                error_setg(errp, "can't resolve host address '%s'", host);
+                return -1;
             }
             saddr->sin_addr = *(struct in_addr *)he->h_addr;
         }
     }
-    port = strtol(p, (char **)&r, 0);
-    if (r == p) {
-        error_setg(errp, "port number '%s' is invalid", p);
+    if (qemu_strtol(port, &r, 0, &p) != 0) {
+        error_setg(errp, "port number '%s' is invalid", port);
+        return -1;
+    }
+    saddr->sin_port = htons(p);
+    return 0;
+}
+
+int parse_host_port(struct sockaddr_in *saddr, const char *str,
+                    Error **errp)
+{
+    gchar **substrings;
+    int ret;
+
+    substrings = g_strsplit(str, ":", 2);
+    if (!substrings || !substrings[0] || !substrings[1]) {
+        error_setg(errp, "host address '%s' doesn't contain ':' "
+                   "separating host from port", str);
         ret = -1;
         goto out;
     }
-    saddr->sin_port = htons(port);
+
+    ret = convert_host_port(saddr, substrings[0], substrings[1], errp);
 
 out:
     g_strfreev(substrings);
-- 
2.35.3

Re: [RFC PATCH 1/6] net: introduce convert_host_port()

[Stefano Brivio]

On Mon,  9 May 2022 19:36:13 +0200
Laurent Vivier <lvivier@redhat.com> wrote:

> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  include/qemu/sockets.h |  2 ++
>  net/net.c              | 62 ++++++++++++++++++++++--------------------
>  2 files changed, 34 insertions(+), 30 deletions(-)
> 
> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
> index 038faa157f59..47194b9732f8 100644
> --- a/include/qemu/sockets.h
> +++ b/include/qemu/sockets.h
> @@ -47,6 +47,8 @@ void socket_listen_cleanup(int fd, Error **errp);
>  int socket_dgram(SocketAddress *remote, SocketAddress *local, Error **errp);
>  
>  /* Old, ipv4 only bits.  Don't use for new code. */
> +int convert_host_port(struct sockaddr_in *saddr, const char *host,
> +                      const char *port, Error **errp);
>  int parse_host_port(struct sockaddr_in *saddr, const char *str,
>                      Error **errp);
>  int socket_init(void);
> diff --git a/net/net.c b/net/net.c
> index a094cf1d2929..58c05c200622 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -66,55 +66,57 @@ static QTAILQ_HEAD(, NetClientState) net_clients;
>  /***********************************************************/
>  /* network device redirectors */
>  
> -int parse_host_port(struct sockaddr_in *saddr, const char *str,
> -                    Error **errp)
> +int convert_host_port(struct sockaddr_in *saddr, const char *host,
> +                      const char *port, Error **errp)
>  {
> -    gchar **substrings;
>      struct hostent *he;
> -    const char *addr, *p, *r;
> -    int port, ret = 0;
> +    const char *r;
> +    long p;
>  
>      memset(saddr, 0, sizeof(*saddr));
>  
> -    substrings = g_strsplit(str, ":", 2);
> -    if (!substrings || !substrings[0] || !substrings[1]) {
> -        error_setg(errp, "host address '%s' doesn't contain ':' "
> -                   "separating host from port", str);
> -        ret = -1;
> -        goto out;
> -    }
> -
> -    addr = substrings[0];
> -    p = substrings[1];
> -
>      saddr->sin_family = AF_INET;
> -    if (addr[0] == '\0') {
> +    if (host[0] == '\0') {
>          saddr->sin_addr.s_addr = 0;
>      } else {
> -        if (qemu_isdigit(addr[0])) {
> -            if (!inet_aton(addr, &saddr->sin_addr)) {
> +        if (qemu_isdigit(host[0])) {
> +            if (!inet_aton(host, &saddr->sin_addr)) {

I was about to observe that this doesn't support IPv6 addresses (which
I guess we'd like to have always in the RFC 3986 form "[address]:port",
as the port is mandatory here), and to propose a small change to bridge
this gap.

Then I realised this is (partially) using GLib, so maybe we want to use
g_network_address_parse() which would, however, give us a
GSocketConnectable object.

At that point, do we want to pass the GsocketConnectable thing around,
or stick to struct sockaddr_in{,6}, filling it here from what GLib
gives us?

-- 
Stefano

Re: [RFC PATCH 1/6] net: introduce convert_host_port()

[Laurent Vivier]

On 10/05/2022 23:24, Stefano Brivio wrote:
> On Mon,  9 May 2022 19:36:13 +0200
> Laurent Vivier <lvivier@redhat.com> wrote:
> 
>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>> ---
>>   include/qemu/sockets.h |  2 ++
>>   net/net.c              | 62 ++++++++++++++++++++++--------------------
>>   2 files changed, 34 insertions(+), 30 deletions(-)
>>
>> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
>> index 038faa157f59..47194b9732f8 100644
>> --- a/include/qemu/sockets.h
>> +++ b/include/qemu/sockets.h
>> @@ -47,6 +47,8 @@ void socket_listen_cleanup(int fd, Error **errp);
>>   int socket_dgram(SocketAddress *remote, SocketAddress *local, Error **errp);
>>   
>>   /* Old, ipv4 only bits.  Don't use for new code. */
>> +int convert_host_port(struct sockaddr_in *saddr, const char *host,
>> +                      const char *port, Error **errp);
>>   int parse_host_port(struct sockaddr_in *saddr, const char *str,
>>                       Error **errp);
>>   int socket_init(void);
>> diff --git a/net/net.c b/net/net.c
>> index a094cf1d2929..58c05c200622 100644
>> --- a/net/net.c
>> +++ b/net/net.c
>> @@ -66,55 +66,57 @@ static QTAILQ_HEAD(, NetClientState) net_clients;
>>   /***********************************************************/
>>   /* network device redirectors */
>>   
>> -int parse_host_port(struct sockaddr_in *saddr, const char *str,
>> -                    Error **errp)
>> +int convert_host_port(struct sockaddr_in *saddr, const char *host,
>> +                      const char *port, Error **errp)
>>   {
>> -    gchar **substrings;
>>       struct hostent *he;
>> -    const char *addr, *p, *r;
>> -    int port, ret = 0;
>> +    const char *r;
>> +    long p;
>>   
>>       memset(saddr, 0, sizeof(*saddr));
>>   
>> -    substrings = g_strsplit(str, ":", 2);
>> -    if (!substrings || !substrings[0] || !substrings[1]) {
>> -        error_setg(errp, "host address '%s' doesn't contain ':' "
>> -                   "separating host from port", str);
>> -        ret = -1;
>> -        goto out;
>> -    }
>> -
>> -    addr = substrings[0];
>> -    p = substrings[1];
>> -
>>       saddr->sin_family = AF_INET;
>> -    if (addr[0] == '\0') {
>> +    if (host[0] == '\0') {
>>           saddr->sin_addr.s_addr = 0;
>>       } else {
>> -        if (qemu_isdigit(addr[0])) {
>> -            if (!inet_aton(addr, &saddr->sin_addr)) {
>> +        if (qemu_isdigit(host[0])) {
>> +            if (!inet_aton(host, &saddr->sin_addr)) {
> 
> I was about to observe that this doesn't support IPv6 addresses (which
> I guess we'd like to have always in the RFC 3986 form "[address]:port",
> as the port is mandatory here), and to propose a small change to bridge
> this gap.
> 
> Then I realised this is (partially) using GLib, so maybe we want to use
> g_network_address_parse() which would, however, give us a
> GSocketConnectable object.
> 
> At that point, do we want to pass the GsocketConnectable thing around,
> or stick to struct sockaddr_in{,6}, filling it here from what GLib
> gives us?
> 

For the new netdev, we should better switch to util/qemu-sockets.c functions that take 
directly a SocketAddress (see socket_connect()).

Thanks,
Laurent

[RFC PATCH 2/6] qapi: net: add socket-ng netdev

[Laurent Vivier]

Copied from socket netdev file and modified to use SocketAddress
to be able to introduce new features like unix socket.

"udp" and "mcast" are squashed into dgram, multicast is detected
according to the IP address type.
"listen" and "connect" modes are changed to "server" and "client".

As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field
of Netdev structure collides with "type" field of SocketAddress),
we detect socket-ng backend and use directly visit_type_Netdev() to
parse the backend parameters.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>

net: socket-ng: replace mode=unicast/multicast by mode=dgram

The multicast mode is detected according to the remote
address type.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 hmp-commands.hx |   2 +-
 net/clients.h   |   3 +
 net/hub.c       |   1 +
 net/meson.build |   1 +
 net/net.c       |  61 ++++
 net/socket-ng.c | 890 ++++++++++++++++++++++++++++++++++++++++++++++++
 qapi/net.json   |  41 ++-
 7 files changed, 996 insertions(+), 3 deletions(-)
 create mode 100644 net/socket-ng.c

diff --git a/hmp-commands.hx b/hmp-commands.hx
index 03e6a73d1f55..74f7c9585ac3 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1269,7 +1269,7 @@ ERST
     {
         .name       = "netdev_add",
         .args_type  = "netdev:O",
-        .params     = "[user|tap|socket|vde|bridge|hubport|netmap|vhost-user],id=str[,prop=value][,...]",
+        .params     = "[user|tap|socket|socket-ng|vde|bridge|hubport|netmap|vhost-user],id=str[,prop=value][,...]",
         .help       = "add host network device",
         .cmd        = hmp_netdev_add,
         .command_completion = netdev_add_completion,
diff --git a/net/clients.h b/net/clients.h
index 92f9b59aedce..8c71a3ba8e97 100644
--- a/net/clients.h
+++ b/net/clients.h
@@ -40,6 +40,9 @@ int net_init_hubport(const Netdev *netdev, const char *name,
 int net_init_socket(const Netdev *netdev, const char *name,
                     NetClientState *peer, Error **errp);
 
+int net_init_socket_ng(const Netdev *netdev, const char *name,
+                       NetClientState *peer, Error **errp);
+
 int net_init_tap(const Netdev *netdev, const char *name,
                  NetClientState *peer, Error **errp);
 
diff --git a/net/hub.c b/net/hub.c
index 1375738bf121..8f9607bfe3dc 100644
--- a/net/hub.c
+++ b/net/hub.c
@@ -313,6 +313,7 @@ void net_hub_check_clients(void)
             case NET_CLIENT_DRIVER_USER:
             case NET_CLIENT_DRIVER_TAP:
             case NET_CLIENT_DRIVER_SOCKET:
+            case NET_CLIENT_DRIVER_SOCKET_NG:
             case NET_CLIENT_DRIVER_VDE:
             case NET_CLIENT_DRIVER_VHOST_USER:
                 has_host_dev = 1;
diff --git a/net/meson.build b/net/meson.build
index c965e83b264b..92a8cde119d2 100644
--- a/net/meson.build
+++ b/net/meson.build
@@ -13,6 +13,7 @@ softmmu_ss.add(files(
   'net.c',
   'queue.c',
   'socket.c',
+  'socket-ng.c',
   'util.c',
 ))
 
diff --git a/net/net.c b/net/net.c
index 58c05c200622..cbc0ff3784b7 100644
--- a/net/net.c
+++ b/net/net.c
@@ -54,6 +54,7 @@
 #include "net/colo-compare.h"
 #include "net/filter.h"
 #include "qapi/string-output-visitor.h"
+#include "qapi/qobject-input-visitor.h"
 
 /* Net bridge is currently not supported for W32. */
 #if !defined(_WIN32)
@@ -63,6 +64,16 @@
 static VMChangeStateEntry *net_change_state_entry;
 static QTAILQ_HEAD(, NetClientState) net_clients;
 
+typedef struct NetdevQueueEntry {
+    Netdev *nd;
+    Location loc;
+    QSIMPLEQ_ENTRY(NetdevQueueEntry) entry;
+} NetdevQueueEntry;
+
+typedef QSIMPLEQ_HEAD(, NetdevQueueEntry) NetdevQueue;
+
+static NetdevQueue nd_queue = QSIMPLEQ_HEAD_INITIALIZER(nd_queue);
+
 /***********************************************************/
 /* network device redirectors */
 
@@ -1003,6 +1014,7 @@ static int (* const net_client_init_fun[NET_CLIENT_DRIVER__MAX])(
 #endif
         [NET_CLIENT_DRIVER_TAP]       = net_init_tap,
         [NET_CLIENT_DRIVER_SOCKET]    = net_init_socket,
+        [NET_CLIENT_DRIVER_SOCKET_NG]  = net_init_socket_ng,
 #ifdef CONFIG_VDE
         [NET_CLIENT_DRIVER_VDE]       = net_init_vde,
 #endif
@@ -1085,6 +1097,7 @@ void show_netdevs(void)
     int idx;
     const char *available_netdevs[] = {
         "socket",
+        "socket-ng",
         "hubport",
         "tap",
 #ifdef CONFIG_SLIRP
@@ -1559,6 +1572,19 @@ int net_init_clients(Error **errp)
 
     QTAILQ_INIT(&net_clients);
 
+    while (!QSIMPLEQ_EMPTY(&nd_queue)) {
+        NetdevQueueEntry *nd = QSIMPLEQ_FIRST(&nd_queue);
+
+        QSIMPLEQ_REMOVE_HEAD(&nd_queue, entry);
+        loc_push_restore(&nd->loc);
+        if (net_client_init1(nd->nd, true, errp) < 0) {
+            return -1;
+        }
+        loc_pop(&nd->loc);
+        qapi_free_Netdev(nd->nd);
+        g_free(nd);
+    }
+
     if (qemu_opts_foreach(qemu_find_opts("netdev"),
                           net_init_netdev, NULL, errp)) {
         return -1;
@@ -1575,8 +1601,43 @@ int net_init_clients(Error **errp)
     return 0;
 }
 
+static bool netdev_is_socket_ng(const char *optarg)
+{
+    static QemuOptsList dummy_opts = {
+        .name = "netdev",
+        .implied_opt_name = "type",
+        .head = QTAILQ_HEAD_INITIALIZER(dummy_opts.head),
+        .desc = { { } },
+    };
+    QemuOpts *opts = qemu_opts_parse(&dummy_opts, optarg, true, &error_fatal);
+    bool is_socket_ng = strcmp(qemu_opt_get(opts, "type"), "socket-ng") == 0;
+
+    qemu_opts_reset(&dummy_opts);
+
+    return is_socket_ng;
+}
+
 int net_client_parse(QemuOptsList *opts_list, const char *optarg)
 {
+    if (netdev_is_socket_ng(optarg)) {
+            /*
+             * socket-ng must accept new style object SocketAddress
+             * like addr.type=inet, ...
+             */
+            Visitor *v;
+            NetdevQueueEntry *nd;
+
+            v = qobject_input_visitor_new_str(optarg, "type",
+                                              &error_fatal);
+            nd = g_new(NetdevQueueEntry, 1);
+            visit_type_Netdev(v, NULL, &nd->nd, &error_fatal);
+            visit_free(v);
+            loc_save(&nd->loc);
+
+            QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry);
+            return 0;
+    }
+
     if (!qemu_opts_parse_noisily(opts_list, optarg, true)) {
         return -1;
     }
diff --git a/net/socket-ng.c b/net/socket-ng.c
new file mode 100644
index 000000000000..0876a4930389
--- /dev/null
+++ b/net/socket-ng.c
@@ -0,0 +1,890 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu/osdep.h"
+
+#include "net/net.h"
+#include "clients.h"
+#include "monitor/monitor.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "qemu/option.h"
+#include "qemu/sockets.h"
+#include "qemu/iov.h"
+#include "qemu/main-loop.h"
+#include "qemu/cutils.h"
+
+typedef struct NetSocketNGState {
+    NetClientState nc;
+    int listen_fd;
+    int fd;
+    SocketReadState rs;
+    unsigned int send_index;      /* number of bytes sent (only SOCK_STREAM) */
+  /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
+    struct sockaddr_in dgram_dst;
+    IOHandler *send_fn;           /* differs between SOCK_STREAM/SOCK_DGRAM */
+    bool read_poll;               /* waiting to receive data? */
+    bool write_poll;              /* waiting to transmit data? */
+} NetSocketNGState;
+
+static void net_socket_accept(void *opaque);
+static void net_socket_writable(void *opaque);
+
+static void net_socket_update_fd_handler(NetSocketNGState *s)
+{
+    qemu_set_fd_handler(s->fd,
+                        s->read_poll ? s->send_fn : NULL,
+                        s->write_poll ? net_socket_writable : NULL,
+                        s);
+}
+
+static void net_socket_read_poll(NetSocketNGState *s, bool enable)
+{
+    s->read_poll = enable;
+    net_socket_update_fd_handler(s);
+}
+
+static void net_socket_write_poll(NetSocketNGState *s, bool enable)
+{
+    s->write_poll = enable;
+    net_socket_update_fd_handler(s);
+}
+
+static void net_socket_writable(void *opaque)
+{
+    NetSocketNGState *s = opaque;
+
+    net_socket_write_poll(s, false);
+
+    qemu_flush_queued_packets(&s->nc);
+}
+
+static ssize_t net_socket_receive(NetClientState *nc, const uint8_t *buf,
+                                  size_t size)
+{
+    NetSocketNGState *s = DO_UPCAST(NetSocketNGState, nc, nc);
+    uint32_t len = htonl(size);
+    struct iovec iov[] = {
+        {
+            .iov_base = &len,
+            .iov_len  = sizeof(len),
+        }, {
+            .iov_base = (void *)buf,
+            .iov_len  = size,
+        },
+    };
+    size_t remaining;
+    ssize_t ret;
+
+    remaining = iov_size(iov, 2) - s->send_index;
+    ret = iov_send(s->fd, iov, 2, s->send_index, remaining);
+
+    if (ret == -1 && errno == EAGAIN) {
+        ret = 0; /* handled further down */
+    }
+    if (ret == -1) {
+        s->send_index = 0;
+        return -errno;
+    }
+    if (ret < (ssize_t)remaining) {
+        s->send_index += ret;
+        net_socket_write_poll(s, true);
+        return 0;
+    }
+    s->send_index = 0;
+    return size;
+}
+
+static ssize_t net_socket_receive_dgram(NetClientState *nc,
+                                        const uint8_t *buf, size_t size)
+{
+    NetSocketNGState *s = DO_UPCAST(NetSocketNGState, nc, nc);
+    ssize_t ret;
+
+    do {
+        if (s->dgram_dst.sin_family != AF_UNIX) {
+            ret = sendto(s->fd, buf, size, 0,
+                         (struct sockaddr *)&s->dgram_dst,
+                         sizeof(s->dgram_dst));
+        } else {
+            ret = send(s->fd, buf, size, 0);
+        }
+    } while (ret == -1 && errno == EINTR);
+
+    if (ret == -1 && errno == EAGAIN) {
+        net_socket_write_poll(s, true);
+        return 0;
+    }
+    return ret;
+}
+
+static void net_socket_send_completed(NetClientState *nc, ssize_t len)
+{
+    NetSocketNGState *s = DO_UPCAST(NetSocketNGState, nc, nc);
+
+    if (!s->read_poll) {
+        net_socket_read_poll(s, true);
+    }
+}
+
+static void net_socket_rs_finalize(SocketReadState *rs)
+{
+    NetSocketNGState *s = container_of(rs, NetSocketNGState, rs);
+
+    if (qemu_send_packet_async(&s->nc, rs->buf,
+                               rs->packet_len,
+                               net_socket_send_completed) == 0) {
+        net_socket_read_poll(s, false);
+    }
+}
+
+static void net_socket_send(void *opaque)
+{
+    NetSocketNGState *s = opaque;
+    int size;
+    int ret;
+    uint8_t buf1[NET_BUFSIZE];
+    const uint8_t *buf;
+
+    size = recv(s->fd, buf1, sizeof(buf1), 0);
+    if (size < 0) {
+        if (errno != EWOULDBLOCK) {
+            goto eoc;
+        }
+    } else if (size == 0) {
+        /* end of connection */
+    eoc:
+        net_socket_read_poll(s, false);
+        net_socket_write_poll(s, false);
+        if (s->listen_fd != -1) {
+            qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
+        }
+        closesocket(s->fd);
+
+        s->fd = -1;
+        net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
+        s->nc.link_down = true;
+        memset(s->nc.info_str, 0, sizeof(s->nc.info_str));
+
+        return;
+    }
+    buf = buf1;
+
+    ret = net_fill_rstate(&s->rs, buf, size);
+
+    if (ret == -1) {
+        goto eoc;
+    }
+}
+
+static void net_socket_send_dgram(void *opaque)
+{
+    NetSocketNGState *s = opaque;
+    int size;
+
+    size = recv(s->fd, s->rs.buf, sizeof(s->rs.buf), 0);
+    if (size < 0) {
+        return;
+    }
+    if (size == 0) {
+        /* end of connection */
+        net_socket_read_poll(s, false);
+        net_socket_write_poll(s, false);
+        return;
+    }
+    if (qemu_send_packet_async(&s->nc, s->rs.buf, size,
+                               net_socket_send_completed) == 0) {
+        net_socket_read_poll(s, false);
+    }
+}
+
+static int net_socket_mcast_create(struct sockaddr_in *mcastaddr,
+                                   struct in_addr *localaddr,
+                                   Error **errp)
+{
+    struct ip_mreq imr;
+    int fd;
+    int val, ret;
+#ifdef __OpenBSD__
+    unsigned char loop;
+#else
+    int loop;
+#endif
+
+    if (!IN_MULTICAST(ntohl(mcastaddr->sin_addr.s_addr))) {
+        error_setg(errp, "specified mcastaddr %s (0x%08x) "
+                   "does not contain a multicast address",
+                   inet_ntoa(mcastaddr->sin_addr),
+                   (int)ntohl(mcastaddr->sin_addr.s_addr));
+        return -1;
+    }
+
+    fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
+    if (fd < 0) {
+        error_setg_errno(errp, errno, "can't create datagram socket");
+        return -1;
+    }
+
+    /*
+     * Allow multiple sockets to bind the same multicast ip and port by setting
+     * SO_REUSEADDR. This is the only situation where SO_REUSEADDR should be set
+     * on windows. Use socket_set_fast_reuse otherwise as it sets SO_REUSEADDR
+     * only on posix systems.
+     */
+    val = 1;
+    ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+    if (ret < 0) {
+        error_setg_errno(errp, errno,
+                         "can't set socket option SO_REUSEADDR");
+        goto fail;
+    }
+
+    ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
+    if (ret < 0) {
+        error_setg_errno(errp, errno, "can't bind ip=%s to socket",
+                         inet_ntoa(mcastaddr->sin_addr));
+        goto fail;
+    }
+
+    /* Add host to multicast group */
+    imr.imr_multiaddr = mcastaddr->sin_addr;
+    if (localaddr) {
+        imr.imr_interface = *localaddr;
+    } else {
+        imr.imr_interface.s_addr = htonl(INADDR_ANY);
+    }
+
+    ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+                     &imr, sizeof(struct ip_mreq));
+    if (ret < 0) {
+        error_setg_errno(errp, errno,
+                         "can't add socket to multicast group %s",
+                         inet_ntoa(imr.imr_multiaddr));
+        goto fail;
+    }
+
+    /* Force mcast msgs to loopback (eg. several QEMUs in same host */
+    loop = 1;
+    ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP,
+                     &loop, sizeof(loop));
+    if (ret < 0) {
+        error_setg_errno(errp, errno,
+                         "can't force multicast message to loopback");
+        goto fail;
+    }
+
+    /* If a bind address is given, only send packets from that address */
+    if (localaddr != NULL) {
+        ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF,
+                         localaddr, sizeof(*localaddr));
+        if (ret < 0) {
+            error_setg_errno(errp, errno,
+                             "can't set the default network send interface");
+            goto fail;
+        }
+    }
+
+    qemu_socket_set_nonblock(fd);
+    return fd;
+fail:
+    if (fd >= 0) {
+        closesocket(fd);
+    }
+    return -1;
+}
+
+static void net_socket_cleanup(NetClientState *nc)
+{
+    NetSocketNGState *s = DO_UPCAST(NetSocketNGState, nc, nc);
+    if (s->fd != -1) {
+        net_socket_read_poll(s, false);
+        net_socket_write_poll(s, false);
+        close(s->fd);
+        s->fd = -1;
+    }
+    if (s->listen_fd != -1) {
+        qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
+        closesocket(s->listen_fd);
+        s->listen_fd = -1;
+    }
+}
+
+static NetClientInfo net_dgram_socket_info = {
+    .type = NET_CLIENT_DRIVER_SOCKET_NG,
+    .size = sizeof(NetSocketNGState),
+    .receive = net_socket_receive_dgram,
+    .cleanup = net_socket_cleanup,
+};
+
+static NetSocketNGState *net_socket_fd_init_dgram(NetClientState *peer,
+                                                const char *model,
+                                                const char *name,
+                                                int fd, int is_fd,
+                                                SocketAddress *mcast,
+                                                Error **errp)
+{
+    struct sockaddr_in saddr;
+    int newfd;
+    NetClientState *nc;
+    NetSocketNGState *s;
+    SocketAddress *sa;
+    SocketAddressType sa_type;
+
+    sa = socket_local_address(fd, errp);
+    if (!sa) {
+        return NULL;
+    }
+    sa_type = sa->type;
+    qapi_free_SocketAddress(sa);
+
+    /*
+     * fd passed: multicast: "learn" dgram_dst address from bound address and
+     * save it. Because this may be "shared" socket from a "master" process,
+     * datagrams would be recv() by ONLY ONE process: we must "clone" this
+     * dgram socket --jjo
+     */
+
+    if (is_fd && mcast != NULL) {
+            if (convert_host_port(&saddr, mcast->u.inet.host,
+                                  mcast->u.inet.port, errp) < 0) {
+                goto err;
+            }
+            /* must be bound */
+            if (saddr.sin_addr.s_addr == 0) {
+                error_setg(errp, "can't setup multicast destination address");
+                goto err;
+            }
+            /* clone dgram socket */
+            newfd = net_socket_mcast_create(&saddr, NULL, errp);
+            if (newfd < 0) {
+                goto err;
+            }
+            /* clone newfd to fd, close newfd */
+            dup2(newfd, fd);
+            close(newfd);
+
+    }
+
+    nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
+
+    s = DO_UPCAST(NetSocketNGState, nc, nc);
+
+    s->fd = fd;
+    s->listen_fd = -1;
+    s->send_fn = net_socket_send_dgram;
+    net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
+    net_socket_read_poll(s, true);
+
+    /* mcast: save bound address as dst */
+    if (is_fd && mcast != NULL) {
+        s->dgram_dst = saddr;
+        snprintf(nc->info_str, sizeof(nc->info_str),
+                 "socket-ng: fd=%d (cloned mcast=%s:%d)",
+                 fd, inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+    } else {
+        if (sa_type == SOCKET_ADDRESS_TYPE_UNIX) {
+            s->dgram_dst.sin_family = AF_UNIX;
+        }
+
+        snprintf(nc->info_str, sizeof(nc->info_str),
+                 "socket-ng: fd=%d %s", fd, SocketAddressType_str(sa_type));
+    }
+
+    return s;
+
+err:
+    closesocket(fd);
+    return NULL;
+}
+
+static void net_socket_connect(void *opaque)
+{
+    NetSocketNGState *s = opaque;
+    s->send_fn = net_socket_send;
+    net_socket_read_poll(s, true);
+}
+
+static NetClientInfo net_socket_info = {
+    .type = NET_CLIENT_DRIVER_SOCKET_NG,
+    .size = sizeof(NetSocketNGState),
+    .receive = net_socket_receive,
+    .cleanup = net_socket_cleanup,
+};
+
+static NetSocketNGState *net_socket_fd_init_stream(NetClientState *peer,
+                                                 const char *model,
+                                                 const char *name,
+                                                 int fd, int is_connected)
+{
+    NetClientState *nc;
+    NetSocketNGState *s;
+
+    nc = qemu_new_net_client(&net_socket_info, peer, model, name);
+
+    snprintf(nc->info_str, sizeof(nc->info_str), "socket-ng: fd=%d", fd);
+
+    s = DO_UPCAST(NetSocketNGState, nc, nc);
+
+    s->fd = fd;
+    s->listen_fd = -1;
+    net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
+
+    /* Disable Nagle algorithm on TCP sockets to reduce latency */
+    socket_set_nodelay(fd);
+
+    if (is_connected) {
+        net_socket_connect(s);
+    } else {
+        qemu_set_fd_handler(s->fd, NULL, net_socket_connect, s);
+    }
+    return s;
+}
+
+static void net_socket_accept(void *opaque)
+{
+    NetSocketNGState *s = opaque;
+    struct sockaddr_in saddr;
+    socklen_t len;
+    int fd;
+
+    for (;;) {
+        len = sizeof(saddr);
+        fd = qemu_accept(s->listen_fd, (struct sockaddr *)&saddr, &len);
+        if (fd < 0 && errno != EINTR) {
+            return;
+        } else if (fd >= 0) {
+            qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
+            break;
+        }
+    }
+
+    s->fd = fd;
+    s->nc.link_down = false;
+    net_socket_connect(s);
+    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
+             "socket-ng: connection from %s:%d",
+             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+}
+
+static int net_socketng_listen_init(NetClientState *peer,
+                                    const char *model,
+                                    const char *name,
+                                    SocketAddress *addr,
+                                    Error **errp)
+{
+    NetClientState *nc;
+    NetSocketNGState *s;
+    int fd, ret;
+
+    switch (addr->type) {
+    case SOCKET_ADDRESS_TYPE_INET: {
+        struct sockaddr_in saddr_in;
+
+        if (convert_host_port(&saddr_in, addr->u.inet.host, addr->u.inet.port,
+                              errp) < 0) {
+            return -1;
+        }
+
+        fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
+        if (fd < 0) {
+            error_setg_errno(errp, errno, "can't create stream socket");
+            return -1;
+        }
+        qemu_socket_set_nonblock(fd);
+
+        socket_set_fast_reuse(fd);
+
+        ret = bind(fd, (struct sockaddr *)&saddr_in, sizeof(saddr_in));
+        if (ret < 0) {
+            error_setg_errno(errp, errno, "can't bind ip=%s to socket",
+                             inet_ntoa(saddr_in.sin_addr));
+            closesocket(fd);
+            return -1;
+        }
+        break;
+    }
+    case SOCKET_ADDRESS_TYPE_UNIX: {
+        error_setg(errp, "only support inet type");
+        return -1;
+    }
+    case SOCKET_ADDRESS_TYPE_FD:
+        fd = monitor_fd_param(monitor_cur(), addr->u.fd.str, errp);
+        if (fd == -1) {
+            return -1;
+        }
+        ret = qemu_socket_try_set_nonblock(fd);
+        if (ret < 0) {
+            error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
+                             name, fd);
+            return -1;
+        }
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    ret = listen(fd, 0);
+    if (ret < 0) {
+        error_setg_errno(errp, errno, "can't listen on socket");
+        closesocket(fd);
+        return -1;
+    }
+
+    nc = qemu_new_net_client(&net_socket_info, peer, model, name);
+    s = DO_UPCAST(NetSocketNGState, nc, nc);
+    s->fd = -1;
+    s->listen_fd = fd;
+    s->nc.link_down = true;
+    net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
+
+    qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
+    return 0;
+}
+
+static int net_socketng_connect_init(NetClientState *peer,
+                                   const char *model,
+                                   const char *name,
+                                   SocketAddress *addr,
+                                   Error **errp)
+{
+    NetSocketNGState *s;
+    int fd, connected, ret;
+    gchar *info_str;
+
+    switch (addr->type) {
+    case SOCKET_ADDRESS_TYPE_INET: {
+        struct sockaddr_in saddr_in;
+
+        if (convert_host_port(&saddr_in, addr->u.inet.host, addr->u.inet.port,
+                              errp) < 0) {
+            return -1;
+        }
+
+        fd = qemu_socket(PF_INET, 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_in, sizeof(saddr_in));
+            if (ret < 0) {
+                if (errno == EINTR || errno == EWOULDBLOCK) {
+                    /* continue */
+                } else if (errno == EINPROGRESS ||
+                           errno == EALREADY ||
+                           errno == EINVAL) {
+                    break;
+                } else {
+                    error_setg_errno(errp, errno, "can't connect socket");
+                    closesocket(fd);
+                    return -1;
+                }
+            } else {
+                connected = 1;
+                break;
+            }
+        }
+        info_str = g_strdup_printf("socket-ng: connect to %s:%d",
+                                   inet_ntoa(saddr_in.sin_addr),
+                                   ntohs(saddr_in.sin_port));
+        break;
+    }
+    case SOCKET_ADDRESS_TYPE_FD:
+        fd = monitor_fd_param(monitor_cur(), addr->u.fd.str, errp);
+        if (fd == -1) {
+            return -1;
+        }
+        ret = qemu_socket_try_set_nonblock(fd);
+        if (ret < 0) {
+            error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
+                             name, fd);
+            return -1;
+        }
+        connected = 1;
+        info_str = g_strdup_printf("socket-ng: connect to fd %d", fd);
+        break;
+    default:
+        error_setg(errp, "only support inet or fd type");
+        return -1;
+    }
+
+    s = net_socket_fd_init_stream(peer, model, name, fd, connected);
+
+    pstrcpy(s->nc.info_str, sizeof(s->nc.info_str), info_str);
+    g_free(info_str);
+
+    return 0;
+}
+
+static int net_socketng_mcast_init(NetClientState *peer,
+                                 const char *model,
+                                 const char *name,
+                                 SocketAddress *remote,
+                                 SocketAddress *local,
+                                 Error **errp)
+{
+    NetSocketNGState *s;
+    int fd, ret;
+    struct sockaddr_in saddr;
+
+    if (remote->type != SOCKET_ADDRESS_TYPE_INET) {
+        error_setg(errp, "multicast only support inet type");
+        return -1;
+    }
+
+    if (convert_host_port(&saddr, remote->u.inet.host, remote->u.inet.port,
+                          errp) < 0) {
+        return -1;
+    }
+
+    if (!local) {
+        fd = net_socket_mcast_create(&saddr, NULL, errp);
+        if (fd < 0) {
+            return -1;
+        }
+    } else {
+        switch (local->type) {
+        case SOCKET_ADDRESS_TYPE_INET: {
+            struct in_addr localaddr;
+
+            if (inet_aton(local->u.inet.host, &localaddr) == 0) {
+                error_setg(errp, "localaddr '%s' is not a valid IPv4 address",
+                           local->u.inet.host);
+                return -1;
+            }
+
+            fd = net_socket_mcast_create(&saddr, &localaddr, errp);
+            if (fd < 0) {
+                return -1;
+            }
+            break;
+        }
+        case SOCKET_ADDRESS_TYPE_FD:
+            fd = monitor_fd_param(monitor_cur(), local->u.fd.str, errp);
+            if (fd == -1) {
+                return -1;
+            }
+            ret = qemu_socket_try_set_nonblock(fd);
+            if (ret < 0) {
+                error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
+                                 name, fd);
+                return -1;
+            }
+            break;
+        default:
+            error_setg(errp, "only support inet or fd type for local");
+            return -1;
+        }
+    }
+
+    s = net_socket_fd_init_dgram(peer, model, name, fd,
+                                 local->type == SOCKET_ADDRESS_TYPE_FD,
+                                 remote, errp);
+    if (!s) {
+        return -1;
+    }
+
+    s->dgram_dst = saddr;
+
+    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
+             "socket-ng: mcast=%s:%d",
+             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+    return 0;
+
+}
+
+static int net_socketng_udp_init(NetClientState *peer,
+                                 const char *model,
+                                 const char *name,
+                                 SocketAddress *remote,
+                                 SocketAddress *local,
+                                 Error **errp)
+{
+    NetSocketNGState *s;
+    int fd, ret;
+    struct sockaddr_in raddr_in;
+    gchar *info_str;
+
+    if (remote) {
+        if (local->type == SOCKET_ADDRESS_TYPE_FD) {
+            error_setg(errp, "don't set remote with local.fd");
+            return -1;
+        }
+        if (remote->type != local->type) {
+            error_setg(errp, "remote and local types must be the same");
+            return -1;
+        }
+    } else {
+        if (local->type != SOCKET_ADDRESS_TYPE_FD) {
+            error_setg(errp, "type=inet and mode=unicast require "
+                             "remote parameter");
+            return -1;
+        }
+    }
+
+    switch (local->type) {
+    case SOCKET_ADDRESS_TYPE_INET: {
+        struct sockaddr_in laddr_in;
+
+        if (convert_host_port(&laddr_in, local->u.inet.host, local->u.inet.port,
+                              errp) < 0) {
+            return -1;
+        }
+
+        if (convert_host_port(&raddr_in, remote->u.inet.host,
+                              remote->u.inet.port, errp) < 0) {
+            return -1;
+        }
+
+        fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
+        if (fd < 0) {
+            error_setg_errno(errp, errno, "can't create datagram socket");
+            return -1;
+        }
+
+        ret = socket_set_fast_reuse(fd);
+        if (ret < 0) {
+            error_setg_errno(errp, errno,
+                             "can't set socket option SO_REUSEADDR");
+            closesocket(fd);
+            return -1;
+        }
+        ret = bind(fd, (struct sockaddr *)&laddr_in, sizeof(laddr_in));
+        if (ret < 0) {
+            error_setg_errno(errp, errno, "can't bind ip=%s to socket",
+                             inet_ntoa(laddr_in.sin_addr));
+            closesocket(fd);
+            return -1;
+        }
+        qemu_socket_set_nonblock(fd);
+
+        info_str = g_strdup_printf("socket-ng: udp=%s:%d/%s:%d",
+                 inet_ntoa(laddr_in.sin_addr), ntohs(laddr_in.sin_port),
+                 inet_ntoa(raddr_in.sin_addr), ntohs(raddr_in.sin_port));
+
+        break;
+    }
+    case SOCKET_ADDRESS_TYPE_FD:
+        fd = monitor_fd_param(monitor_cur(), local->u.fd.str, errp);
+        if (fd == -1) {
+            return -1;
+        }
+        ret = qemu_socket_try_set_nonblock(fd);
+        if (ret < 0) {
+            error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
+                             name, fd);
+            return -1;
+        }
+        break;
+    default:
+        error_setg(errp, "only support inet or fd type for local");
+        return -1;
+    }
+
+    s = net_socket_fd_init_dgram(peer, model, name, fd, 0, NULL, errp);
+    if (!s) {
+        return -1;
+    }
+
+    if (remote) {
+        s->dgram_dst = raddr_in;
+
+        pstrcpy(s->nc.info_str, sizeof(s->nc.info_str), info_str);
+        g_free(info_str);
+    }
+    return 0;
+}
+
+static int net_socketng_dgram_init(NetClientState *peer,
+                                 const char *model,
+                                 const char *name,
+                                 SocketAddress *remote,
+                                 SocketAddress *local,
+                                 Error **errp)
+{
+    /* detect multicast address */
+    if (remote && remote->type == SOCKET_ADDRESS_TYPE_INET) {
+        struct sockaddr_in mcastaddr;
+
+        if (convert_host_port(&mcastaddr, remote->u.inet.host,
+                              remote->u.inet.port, errp) < 0) {
+            return -1;
+        }
+
+        if (IN_MULTICAST(ntohl(mcastaddr.sin_addr.s_addr))) {
+            return net_socketng_mcast_init(peer, model, name, remote, local,
+                                           errp);
+        }
+    }
+    /* unicast address */
+    if (!local) {
+        error_setg(errp, "mode=dgram requires local= parameter");
+        return -1;
+    }
+    return net_socketng_udp_init(peer, model, name, remote, local, errp);
+}
+
+int net_init_socket_ng(const Netdev *netdev, const char *name,
+                    NetClientState *peer, Error **errp)
+{
+    const NetdevSocketNGOptions *sock;
+
+    assert(netdev->type == NET_CLIENT_DRIVER_SOCKET_NG);
+    sock = &netdev->u.socket_ng;
+
+    switch (sock->mode) {
+    case NETDEV_SOCKETNG_MODE_DGRAM:
+        return net_socketng_dgram_init(peer, "socket", name, sock->remote,
+                                       sock->local, errp);
+    case NETDEV_SOCKETNG_MODE_SERVER:
+        if (!sock->has_addr) {
+            error_setg(errp, "mode=server requires addr parameter");
+            return -1;
+        }
+        if (sock->has_remote || sock->has_local) {
+            error_setg(errp,
+                 "local and remote parameters cannot be used with mode=server");
+            return -1;
+        }
+        return net_socketng_listen_init(peer, "socket", name, sock->addr, errp);
+    case NETDEV_SOCKETNG_MODE_CLIENT:
+        if (!sock->has_addr) {
+            error_setg(errp, "mode=client requires addr parameter");
+            return -1;
+        }
+        if (sock->has_remote || sock->has_local) {
+            error_setg(errp,
+                 "local and remote parameters cannot be used with mode=client");
+            return -1;
+        }
+        return net_socketng_connect_init(peer, "socket", name, sock->addr,
+                                         errp);
+    default:
+        g_assert_not_reached();
+    }
+
+    g_assert_not_reached();
+}
diff --git a/qapi/net.json b/qapi/net.json
index b92f3f5fb444..2b31101e6641 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -7,6 +7,7 @@
 ##
 
 { 'include': 'common.json' }
+{ 'include': 'sockets.json' }
 
 ##
 # @set_link:
@@ -452,6 +453,40 @@
     '*vhostdev':     'str',
     '*queues':       'int' } }
 
+##
+# @NetdevSocketNGMode:
+#
+# @dgram: UDP mode
+#
+# @server: TCP server mode
+#
+# @client: TCP client mode
+#
+# Legacy NetdevSocketOptions only accepts one of:
+# "fd", "udp", "mcast" and "udp".
+# we map:
+#   "udp", "mcast" -> "dgram"
+#   "listen"       -> "server"
+#   "connect"      -> "client"
+#
+# Since: 7.1
+#
+##
+{ 'enum': 'NetdevSocketNGMode',
+  'data':  [ 'dgram', 'server', 'client' ] }
+
+##
+# @NetdevSocketNGOptions:
+#
+# Since: 7.1
+##
+{ 'struct': 'NetdevSocketNGOptions',
+  'data': {
+    'mode':    'NetdevSocketNGMode',
+    '*addr':   'SocketAddress',
+    '*remote': 'SocketAddress',
+    '*local':  'SocketAddress' } }
+
 ##
 # @NetClientDriver:
 #
@@ -463,7 +498,8 @@
 ##
 { 'enum': 'NetClientDriver',
   'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'vde',
-            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
+            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa',
+            'socket-ng' ] }
 
 ##
 # @Netdev:
@@ -492,7 +528,8 @@
     'hubport':  'NetdevHubPortOptions',
     'netmap':   'NetdevNetmapOptions',
     'vhost-user': 'NetdevVhostUserOptions',
-    'vhost-vdpa': 'NetdevVhostVDPAOptions' } }
+    'vhost-vdpa': 'NetdevVhostVDPAOptions',
+    'socket-ng': 'NetdevSocketNGOptions' } }
 
 ##
 # @RxState:
-- 
2.35.3

Re: [RFC PATCH 2/6] qapi: net: add socket-ng netdev

[Stefano Brivio]

On Mon,  9 May 2022 19:36:14 +0200
Laurent Vivier <lvivier@redhat.com> wrote:

> Copied from socket netdev file and modified to use SocketAddress
> to be able to introduce new features like unix socket.
> 
> "udp" and "mcast" are squashed into dgram, multicast is detected
> according to the IP address type.
> "listen" and "connect" modes are changed to "server" and "client".
> 
> As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field
> of Netdev structure collides with "type" field of SocketAddress),
> we detect socket-ng backend and use directly visit_type_Netdev() to
> parse the backend parameters.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> 
> net: socket-ng: replace mode=unicast/multicast by mode=dgram
> 
> The multicast mode is detected according to the remote
> address type.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  hmp-commands.hx |   2 +-
>  net/clients.h   |   3 +
>  net/hub.c       |   1 +
>  net/meson.build |   1 +
>  net/net.c       |  61 ++++
>  net/socket-ng.c | 890 ++++++++++++++++++++++++++++++++++++++++++++++++
>  qapi/net.json   |  41 ++-
>  7 files changed, 996 insertions(+), 3 deletions(-)
>  create mode 100644 net/socket-ng.c
> 
> [...]
>
> +static int net_socketng_connect_init(NetClientState *peer,
> +                                   const char *model,
> +                                   const char *name,
> +                                   SocketAddress *addr,
> +                                   Error **errp)
> +{
> +    NetSocketNGState *s;
> +    int fd, connected, ret;
> +    gchar *info_str;
> +
> +    switch (addr->type) {
> +    case SOCKET_ADDRESS_TYPE_INET: {
> +        struct sockaddr_in saddr_in;
> +
> +        if (convert_host_port(&saddr_in, addr->u.inet.host, addr->u.inet.port,
> +                              errp) < 0) {
> +            return -1;
> +        }
> +
> +        fd = qemu_socket(PF_INET, 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_in, sizeof(saddr_in));
> +            if (ret < 0) {
> +                if (errno == EINTR || errno == EWOULDBLOCK) {
> +                    /* continue */
> +                } else if (errno == EINPROGRESS ||
> +                           errno == EALREADY ||
> +                           errno == EINVAL) {

I guess we should report failure and close the socket on EINVAL, there
are no chances the connection will eventually succeed. I actually
proposed this change (after some debugging frustration) in my quick and
dirty series to get AF_UNIX sockets working:

	https://lore.kernel.org/all/a6d475147682de1fe3b14eb325f4247e013e8440.1619190878.git.sbrivio@redhat.com/

> +                    break;
> +                } else {
> +                    error_setg_errno(errp, errno, "can't connect socket");
> +                    closesocket(fd);
> +                    return -1;
> +                }
>
> [...]
>
> diff --git a/qapi/net.json b/qapi/net.json
> index b92f3f5fb444..2b31101e6641 100644
> --- a/qapi/net.json
> +++ b/qapi/net.json
> @@ -7,6 +7,7 @@
>  ##
>  
>  { 'include': 'common.json' }
> +{ 'include': 'sockets.json' }
>  
>  ##
>  # @set_link:
> @@ -452,6 +453,40 @@
>      '*vhostdev':     'str',
>      '*queues':       'int' } }
>  
> +##
> +# @NetdevSocketNGMode:
> +#
> +# @dgram: UDP mode
> +#
> +# @server: TCP server mode
> +#
> +# @client: TCP client mode
> +#
> +# Legacy NetdevSocketOptions only accepts one of:
> +# "fd", "udp", "mcast" and "udp".
> +# we map:
> +#   "udp", "mcast" -> "dgram"
> +#   "listen"       -> "server"
> +#   "connect"      -> "client"
> +#
> +# Since: 7.1
> +#
> +##
> +{ 'enum': 'NetdevSocketNGMode',
> +  'data':  [ 'dgram', 'server', 'client' ] }
> +
> +##
> +# @NetdevSocketNGOptions:
> +#
> +# Since: 7.1
> +##
> +{ 'struct': 'NetdevSocketNGOptions',
> +  'data': {
> +    'mode':    'NetdevSocketNGMode',
> +    '*addr':   'SocketAddress',
> +    '*remote': 'SocketAddress',
> +    '*local':  'SocketAddress' } }
> +
>  ##
>  # @NetClientDriver:
>  #
> @@ -463,7 +498,8 @@
>  ##
>  { 'enum': 'NetClientDriver',
>    'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'vde',
> -            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
> +            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa',
> +            'socket-ng' ] }

I don't know if this is an issue, but I couldn't figure out the reason
for this difference either:

- with the old socket option, I can pass something like:

    -net socket,fd=5 -net nic,model=virtio

  and frames are sent to/received from socket number 5 (which I
  pre-opened)

- with the new option, and something like:

    -netdev socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/test.socket -net nic,model=virtio,id=hostnet0

  I get a connection on the socket, but the virtio-net device is not
  connected to it (no frames received/sent).

  However, if instead of "-net nic" I pass this:

    -device virtio-net-pci,netdev=socket0

  everything works.

-- 
Stefano

Re: [RFC PATCH 2/6] qapi: net: add socket-ng netdev

[Laurent Vivier]

On 10/05/2022 23:24, Stefano Brivio wrote:
...
> I don't know if this is an issue, but I couldn't figure out the reason
> for this difference either:
> 
> - with the old socket option, I can pass something like:
> 
>      -net socket,fd=5 -net nic,model=virtio
> 
>    and frames are sent to/received from socket number 5 (which I
>    pre-opened)
> 
> - with the new option, and something like:
> 
>      -netdev socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/test.socket -net nic,model=virtio,id=hostnet0
> 
>    I get a connection on the socket, but the virtio-net device is not
>    connected to it (no frames received/sent).
> 
>    However, if instead of "-net nic" I pass this:
> 
>      -device virtio-net-pci,netdev=socket0
> 
>    everything works.
> 

I think the problem is with the hub.

When it works:

     -net socket,udp=localhost:1235,localaddr=localhost:1234 \
     -net nic,model=virtio,macaddr=9a:2b:2c:2d:2e:2f

     (qemu) info network
     hub 0
      \ hub0port1: virtio-net-pci.0: 
index=0,type=nic,model=virtio-net-pci,macaddr=9a:2b:2c:2d:2e:2f
      \ hub0port0: #net039: index=0,type=socket,socket: udp=127.0.0.1:1235

When it doesn't work (with the upcoming new syntax...):

     -net dgram,id=socket0,local.type=inet,local.host=localhost,local.port=1234,\
                           remote.type=inet,remote.host=localhost,remote.port=1235
     -net nic,model=virtio,macaddr=9a:2b:2c:2d:2e:2f

     (qemu) info network
     hub 0
      \ hub0port0: virtio-net-pci.0: 
index=0,type=nic,model=virtio-net-pci,macaddr=9a:2b:2c:2d:2e:2f
     socket0: index=0,type=dgram,udp=127.0.0.1:1234/127.0.0.1:1235

We can see socket0 is not linked to the hub (hub0port0)

With "-device" it works because it doesn't use the hub but the netdev id:

     -device virtio-net,mac=9a:2b:2c:2d:2e:2f,netdev=socket0

     virtio-net-pci.0: index=0,type=nic,model=virtio-net-pci,macaddr=9a:2b:2c:2d:2e:f
      \ socket0: index=0,type=dgram,udp=127.0.0.1:1234/127.0.0.1:1235


I'm investigating...

Thanks,
Laurent

[RFC PATCH 3/6] net: socket-ng: add unix socket for server and client mode.

[Laurent Vivier]

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 net/socket-ng.c | 109 ++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 101 insertions(+), 8 deletions(-)

diff --git a/net/socket-ng.c b/net/socket-ng.c
index 0876a4930389..2c70440a2b57 100644
--- a/net/socket-ng.c
+++ b/net/socket-ng.c
@@ -382,7 +382,6 @@ static NetSocketNGState *net_socket_fd_init_dgram(NetClientState *peer,
             /* clone newfd to fd, close newfd */
             dup2(newfd, fd);
             close(newfd);
-
     }
 
     nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
@@ -463,7 +462,7 @@ static NetSocketNGState *net_socket_fd_init_stream(NetClientState *peer,
 static void net_socket_accept(void *opaque)
 {
     NetSocketNGState *s = opaque;
-    struct sockaddr_in saddr;
+    struct sockaddr_storage saddr;
     socklen_t len;
     int fd;
 
@@ -481,9 +480,27 @@ static void net_socket_accept(void *opaque)
     s->fd = fd;
     s->nc.link_down = false;
     net_socket_connect(s);
-    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
-             "socket-ng: 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),
+                 "socket-ng: 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),
+                 "socket-ng: connect from %s", saddr_un.sun_path);
+        break;
+    }
+    default:
+        g_assert_not_reached();
+    }
 }
 
 static int net_socketng_listen_init(NetClientState *peer,
@@ -524,8 +541,40 @@ static int net_socketng_listen_init(NetClientState *peer,
         break;
     }
     case SOCKET_ADDRESS_TYPE_UNIX: {
-        error_setg(errp, "only support inet type");
-        return -1;
+        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));
+        }
+
+        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);
@@ -612,6 +661,50 @@ static int net_socketng_connect_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));
+        }
+
+        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 ||
+                           errno == EINVAL) {
+                    break;
+                } else {
+                    error_setg_errno(errp, errno, "can't connect socket");
+                    closesocket(fd);
+                    return -1;
+                }
+            } else {
+                connected = 1;
+                break;
+            }
+        }
+        info_str = g_strdup_printf("socket-ng: 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) {
@@ -627,7 +720,7 @@ static int net_socketng_connect_init(NetClientState *peer,
         info_str = g_strdup_printf("socket-ng: 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;
     }
 
-- 
2.35.3

[RFC PATCH 4/6] net: socket-ng: make dgram_dst generic

[Laurent Vivier]

dgram_dst is a sockaddr_in structure. To be able to use it with
unix socket, use a pointer to a generic sockaddr structure.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 net/socket-ng.c | 76 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 46 insertions(+), 30 deletions(-)

diff --git a/net/socket-ng.c b/net/socket-ng.c
index 2c70440a2b57..0056924dc02b 100644
--- a/net/socket-ng.c
+++ b/net/socket-ng.c
@@ -40,8 +40,8 @@ typedef struct NetSocketNGState {
     int fd;
     SocketReadState rs;
     unsigned int send_index;      /* number of bytes sent (only SOCK_STREAM) */
-  /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
-    struct sockaddr_in dgram_dst;
+                     /* contains destination iff connectionless (SOCK_DGRAM) */
+    struct sockaddr *dgram_dst;
     IOHandler *send_fn;           /* differs between SOCK_STREAM/SOCK_DGRAM */
     bool read_poll;               /* waiting to receive data? */
     bool write_poll;              /* waiting to transmit data? */
@@ -122,10 +122,9 @@ static ssize_t net_socket_receive_dgram(NetClientState *nc,
     ssize_t ret;
 
     do {
-        if (s->dgram_dst.sin_family != AF_UNIX) {
-            ret = sendto(s->fd, buf, size, 0,
-                         (struct sockaddr *)&s->dgram_dst,
-                         sizeof(s->dgram_dst));
+        if (s->dgram_dst) {
+            ret = sendto(s->fd, buf, size, 0, s->dgram_dst,
+                         sizeof(struct sockaddr_in));
         } else {
             ret = send(s->fd, buf, size, 0);
         }
@@ -327,6 +326,8 @@ static void net_socket_cleanup(NetClientState *nc)
         closesocket(s->listen_fd);
         s->listen_fd = -1;
     }
+    g_free(s->dgram_dst);
+    s->dgram_dst = NULL;
 }
 
 static NetClientInfo net_dgram_socket_info = {
@@ -343,7 +344,7 @@ static NetSocketNGState *net_socket_fd_init_dgram(NetClientState *peer,
                                                 SocketAddress *mcast,
                                                 Error **errp)
 {
-    struct sockaddr_in saddr;
+    struct sockaddr_in *saddr = NULL;
     int newfd;
     NetClientState *nc;
     NetSocketNGState *s;
@@ -365,17 +366,19 @@ static NetSocketNGState *net_socket_fd_init_dgram(NetClientState *peer,
      */
 
     if (is_fd && mcast != NULL) {
-            if (convert_host_port(&saddr, mcast->u.inet.host,
-                                  mcast->u.inet.port, errp) < 0) {
+            saddr = g_new(struct sockaddr_in, 1);
+
+            if (convert_host_port(saddr, mcast->u.inet.host, mcast->u.inet.port,
+                                  errp) < 0) {
                 goto err;
             }
             /* must be bound */
-            if (saddr.sin_addr.s_addr == 0) {
+            if (saddr->sin_addr.s_addr == 0) {
                 error_setg(errp, "can't setup multicast destination address");
                 goto err;
             }
             /* clone dgram socket */
-            newfd = net_socket_mcast_create(&saddr, NULL, errp);
+            newfd = net_socket_mcast_create(saddr, NULL, errp);
             if (newfd < 0) {
                 goto err;
             }
@@ -395,16 +398,13 @@ static NetSocketNGState *net_socket_fd_init_dgram(NetClientState *peer,
     net_socket_read_poll(s, true);
 
     /* mcast: save bound address as dst */
-    if (is_fd && mcast != NULL) {
-        s->dgram_dst = saddr;
+    if (saddr) {
+        g_assert(s->dgram_dst == NULL);
+        s->dgram_dst = (struct sockaddr *)saddr;
         snprintf(nc->info_str, sizeof(nc->info_str),
                  "socket-ng: fd=%d (cloned mcast=%s:%d)",
-                 fd, inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+                 fd, inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port));
     } else {
-        if (sa_type == SOCKET_ADDRESS_TYPE_UNIX) {
-            s->dgram_dst.sin_family = AF_UNIX;
-        }
-
         snprintf(nc->info_str, sizeof(nc->info_str),
                  "socket-ng: fd=%d %s", fd, SocketAddressType_str(sa_type));
     }
@@ -412,6 +412,7 @@ static NetSocketNGState *net_socket_fd_init_dgram(NetClientState *peer,
     return s;
 
 err:
+    g_free(saddr);
     closesocket(fd);
     return NULL;
 }
@@ -741,21 +742,24 @@ static int net_socketng_mcast_init(NetClientState *peer,
 {
     NetSocketNGState *s;
     int fd, ret;
-    struct sockaddr_in saddr;
+    struct sockaddr_in *saddr;
 
     if (remote->type != SOCKET_ADDRESS_TYPE_INET) {
         error_setg(errp, "multicast only support inet type");
         return -1;
     }
 
-    if (convert_host_port(&saddr, remote->u.inet.host, remote->u.inet.port,
+    saddr = g_new(struct sockaddr_in, 1);
+    if (convert_host_port(saddr, remote->u.inet.host, remote->u.inet.port,
                           errp) < 0) {
+        g_free(saddr);
         return -1;
     }
 
     if (!local) {
-        fd = net_socket_mcast_create(&saddr, NULL, errp);
+        fd = net_socket_mcast_create(saddr, NULL, errp);
         if (fd < 0) {
+            g_free(saddr);
             return -1;
         }
     } else {
@@ -764,13 +768,15 @@ static int net_socketng_mcast_init(NetClientState *peer,
             struct in_addr localaddr;
 
             if (inet_aton(local->u.inet.host, &localaddr) == 0) {
+                g_free(saddr);
                 error_setg(errp, "localaddr '%s' is not a valid IPv4 address",
                            local->u.inet.host);
                 return -1;
             }
 
-            fd = net_socket_mcast_create(&saddr, &localaddr, errp);
+            fd = net_socket_mcast_create(saddr, &localaddr, errp);
             if (fd < 0) {
+                g_free(saddr);
                 return -1;
             }
             break;
@@ -778,16 +784,19 @@ static int net_socketng_mcast_init(NetClientState *peer,
         case SOCKET_ADDRESS_TYPE_FD:
             fd = monitor_fd_param(monitor_cur(), local->u.fd.str, errp);
             if (fd == -1) {
+                g_free(saddr);
                 return -1;
             }
             ret = qemu_socket_try_set_nonblock(fd);
             if (ret < 0) {
+                g_free(saddr);
                 error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
                                  name, fd);
                 return -1;
             }
             break;
         default:
+            g_free(saddr);
             error_setg(errp, "only support inet or fd type for local");
             return -1;
         }
@@ -797,14 +806,17 @@ static int net_socketng_mcast_init(NetClientState *peer,
                                  local->type == SOCKET_ADDRESS_TYPE_FD,
                                  remote, errp);
     if (!s) {
+        g_free(saddr);
         return -1;
     }
 
-    s->dgram_dst = saddr;
+    g_assert(s->dgram_dst == NULL);
+    s->dgram_dst = (struct sockaddr *)saddr;
 
     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
              "socket-ng: mcast=%s:%d",
-             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+             inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port));
+
     return 0;
 
 }
@@ -818,8 +830,8 @@ static int net_socketng_udp_init(NetClientState *peer,
 {
     NetSocketNGState *s;
     int fd, ret;
-    struct sockaddr_in raddr_in;
     gchar *info_str;
+    struct sockaddr *dgram_dst;
 
     if (remote) {
         if (local->type == SOCKET_ADDRESS_TYPE_FD) {
@@ -840,7 +852,7 @@ static int net_socketng_udp_init(NetClientState *peer,
 
     switch (local->type) {
     case SOCKET_ADDRESS_TYPE_INET: {
-        struct sockaddr_in laddr_in;
+        struct sockaddr_in laddr_in, raddr_in;
 
         if (convert_host_port(&laddr_in, local->u.inet.host, local->u.inet.port,
                               errp) < 0) {
@@ -874,9 +886,12 @@ static int net_socketng_udp_init(NetClientState *peer,
         }
         qemu_socket_set_nonblock(fd);
 
+        dgram_dst = g_malloc(sizeof(raddr_in));
+        memcpy(dgram_dst, &raddr_in, sizeof(raddr_in));
+
         info_str = g_strdup_printf("socket-ng: udp=%s:%d/%s:%d",
-                 inet_ntoa(laddr_in.sin_addr), ntohs(laddr_in.sin_port),
-                 inet_ntoa(raddr_in.sin_addr), ntohs(raddr_in.sin_port));
+                        inet_ntoa(laddr_in.sin_addr), ntohs(laddr_in.sin_port),
+                        inet_ntoa(raddr_in.sin_addr), ntohs(raddr_in.sin_port));
 
         break;
     }
@@ -903,13 +918,14 @@ static int net_socketng_udp_init(NetClientState *peer,
     }
 
     if (remote) {
-        s->dgram_dst = raddr_in;
+        g_assert(s->dgram_dst == NULL);
+        s->dgram_dst = dgram_dst;
 
         pstrcpy(s->nc.info_str, sizeof(s->nc.info_str), info_str);
         g_free(info_str);
     }
     return 0;
-}
+};
 
 static int net_socketng_dgram_init(NetClientState *peer,
                                  const char *model,
-- 
2.35.3

Re: [RFC PATCH 4/6] net: socket-ng: make dgram_dst generic

[Stefano Brivio]

On Mon,  9 May 2022 19:36:16 +0200
Laurent Vivier <lvivier@redhat.com> wrote:

> dgram_dst is a sockaddr_in structure. To be able to use it with
> unix socket, use a pointer to a generic sockaddr structure.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  net/socket-ng.c | 76 ++++++++++++++++++++++++++++++-------------------
>  1 file changed, 46 insertions(+), 30 deletions(-)
> 
> diff --git a/net/socket-ng.c b/net/socket-ng.c
> index 2c70440a2b57..0056924dc02b 100644
> --- a/net/socket-ng.c
> +++ b/net/socket-ng.c
>
> [...]
>
> @@ -903,13 +918,14 @@ static int net_socketng_udp_init(NetClientState *peer,
>      }
>  
>      if (remote) {
> -        s->dgram_dst = raddr_in;
> +        g_assert(s->dgram_dst == NULL);
> +        s->dgram_dst = dgram_dst;
>  
>          pstrcpy(s->nc.info_str, sizeof(s->nc.info_str), info_str);
>          g_free(info_str);
>      }
>      return 0;
> -}
> +};

Stray semicolon (I guess not reported by gcc without -pedantic).

-- 
Stefano

[RFC PATCH 5/6] net: socket-ng: move mcast specific code from net_socket_fd_init_dgram()

[Laurent Vivier]

It is less complex to manage special cases directly in
net_socketng_mcast_init() and net_socketng_udp_init().

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 net/socket-ng.c | 144 ++++++++++++++++++++++++------------------------
 1 file changed, 73 insertions(+), 71 deletions(-)

diff --git a/net/socket-ng.c b/net/socket-ng.c
index 0056924dc02b..aabdd0eed381 100644
--- a/net/socket-ng.c
+++ b/net/socket-ng.c
@@ -340,52 +340,11 @@ static NetClientInfo net_dgram_socket_info = {
 static NetSocketNGState *net_socket_fd_init_dgram(NetClientState *peer,
                                                 const char *model,
                                                 const char *name,
-                                                int fd, int is_fd,
-                                                SocketAddress *mcast,
+                                                int fd,
                                                 Error **errp)
 {
-    struct sockaddr_in *saddr = NULL;
-    int newfd;
     NetClientState *nc;
     NetSocketNGState *s;
-    SocketAddress *sa;
-    SocketAddressType sa_type;
-
-    sa = socket_local_address(fd, errp);
-    if (!sa) {
-        return NULL;
-    }
-    sa_type = sa->type;
-    qapi_free_SocketAddress(sa);
-
-    /*
-     * fd passed: multicast: "learn" dgram_dst address from bound address and
-     * save it. Because this may be "shared" socket from a "master" process,
-     * datagrams would be recv() by ONLY ONE process: we must "clone" this
-     * dgram socket --jjo
-     */
-
-    if (is_fd && mcast != NULL) {
-            saddr = g_new(struct sockaddr_in, 1);
-
-            if (convert_host_port(saddr, mcast->u.inet.host, mcast->u.inet.port,
-                                  errp) < 0) {
-                goto err;
-            }
-            /* must be bound */
-            if (saddr->sin_addr.s_addr == 0) {
-                error_setg(errp, "can't setup multicast destination address");
-                goto err;
-            }
-            /* clone dgram socket */
-            newfd = net_socket_mcast_create(saddr, NULL, errp);
-            if (newfd < 0) {
-                goto err;
-            }
-            /* clone newfd to fd, close newfd */
-            dup2(newfd, fd);
-            close(newfd);
-    }
 
     nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
 
@@ -397,24 +356,7 @@ static NetSocketNGState *net_socket_fd_init_dgram(NetClientState *peer,
     net_socket_rs_init(&s->rs, net_socket_rs_finalize, false);
     net_socket_read_poll(s, true);
 
-    /* mcast: save bound address as dst */
-    if (saddr) {
-        g_assert(s->dgram_dst == NULL);
-        s->dgram_dst = (struct sockaddr *)saddr;
-        snprintf(nc->info_str, sizeof(nc->info_str),
-                 "socket-ng: fd=%d (cloned mcast=%s:%d)",
-                 fd, inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port));
-    } else {
-        snprintf(nc->info_str, sizeof(nc->info_str),
-                 "socket-ng: fd=%d %s", fd, SocketAddressType_str(sa_type));
-    }
-
     return s;
-
-err:
-    g_free(saddr);
-    closesocket(fd);
-    return NULL;
 }
 
 static void net_socket_connect(void *opaque)
@@ -743,6 +685,7 @@ static int net_socketng_mcast_init(NetClientState *peer,
     NetSocketNGState *s;
     int fd, ret;
     struct sockaddr_in *saddr;
+    gchar *info_str;
 
     if (remote->type != SOCKET_ADDRESS_TYPE_INET) {
         error_setg(errp, "multicast only support inet type");
@@ -762,6 +705,9 @@ static int net_socketng_mcast_init(NetClientState *peer,
             g_free(saddr);
             return -1;
         }
+        info_str = g_strdup_printf("socket-ng: mcast=%s:%d",
+                                   inet_ntoa(saddr->sin_addr),
+                                   ntohs(saddr->sin_port));
     } else {
         switch (local->type) {
         case SOCKET_ADDRESS_TYPE_INET: {
@@ -779,9 +725,14 @@ static int net_socketng_mcast_init(NetClientState *peer,
                 g_free(saddr);
                 return -1;
             }
+            info_str = g_strdup_printf("socket-ng: mcast=%s:%d",
+                                       inet_ntoa(saddr->sin_addr),
+                                       ntohs(saddr->sin_port));
             break;
         }
-        case SOCKET_ADDRESS_TYPE_FD:
+        case SOCKET_ADDRESS_TYPE_FD: {
+            int newfd;
+
             fd = monitor_fd_param(monitor_cur(), local->u.fd.str, errp);
             if (fd == -1) {
                 g_free(saddr);
@@ -794,7 +745,46 @@ static int net_socketng_mcast_init(NetClientState *peer,
                                  name, fd);
                 return -1;
             }
+
+            /*
+             * fd passed: multicast: "learn" dgram_dst address from bound
+             * address and save it. Because this may be "shared" socket from a
+             * "master" process, datagrams would be recv() by ONLY ONE process:
+             * we must "clone" this dgram socket --jjo
+             */
+
+            saddr = g_new(struct sockaddr_in, 1);
+
+            if (convert_host_port(saddr, local->u.inet.host, local->u.inet.port,
+                                  errp) < 0) {
+                g_free(saddr);
+                closesocket(fd);
+                return -1;
+            }
+
+            /* must be bound */
+            if (saddr->sin_addr.s_addr == 0) {
+                error_setg(errp, "can't setup multicast destination address");
+                g_free(saddr);
+                closesocket(fd);
+                return -1;
+            }
+            /* clone dgram socket */
+            newfd = net_socket_mcast_create(saddr, NULL, errp);
+            if (newfd < 0) {
+                g_free(saddr);
+                closesocket(fd);
+                return -1;
+            }
+            /* clone newfd to fd, close newfd */
+            dup2(newfd, fd);
+            close(newfd);
+
+            info_str = g_strdup_printf("socket-ng: fd=%d (cloned mcast=%s:%d)",
+                                       fd, inet_ntoa(saddr->sin_addr),
+                                       ntohs(saddr->sin_port));
             break;
+        }
         default:
             g_free(saddr);
             error_setg(errp, "only support inet or fd type for local");
@@ -802,9 +792,7 @@ static int net_socketng_mcast_init(NetClientState *peer,
         }
     }
 
-    s = net_socket_fd_init_dgram(peer, model, name, fd,
-                                 local->type == SOCKET_ADDRESS_TYPE_FD,
-                                 remote, errp);
+    s = net_socket_fd_init_dgram(peer, model, name, fd, errp);
     if (!s) {
         g_free(saddr);
         return -1;
@@ -813,9 +801,8 @@ static int net_socketng_mcast_init(NetClientState *peer,
     g_assert(s->dgram_dst == NULL);
     s->dgram_dst = (struct sockaddr *)saddr;
 
-    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
-             "socket-ng: mcast=%s:%d",
-             inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port));
+    pstrcpy(s->nc.info_str, sizeof(s->nc.info_str), info_str);
+    g_free(info_str);
 
     return 0;
 
@@ -895,7 +882,10 @@ static int net_socketng_udp_init(NetClientState *peer,
 
         break;
     }
-    case SOCKET_ADDRESS_TYPE_FD:
+    case SOCKET_ADDRESS_TYPE_FD: {
+        SocketAddress *sa;
+        SocketAddressType sa_type;
+
         fd = monitor_fd_param(monitor_cur(), local->u.fd.str, errp);
         if (fd == -1) {
             return -1;
@@ -906,23 +896,35 @@ static int net_socketng_udp_init(NetClientState *peer,
                              name, fd);
             return -1;
         }
+
+        sa = socket_local_address(fd, errp);
+        if (sa) {
+            sa_type = sa->type;
+            qapi_free_SocketAddress(sa);
+
+            info_str = g_strdup_printf("socket: fd=%d %s", fd,
+                                       SocketAddressType_str(sa_type));
+        } else {
+            info_str = g_strdup_printf("socket: fd=%d", fd);
+        }
         break;
+    }
     default:
         error_setg(errp, "only support inet or fd type for local");
         return -1;
     }
 
-    s = net_socket_fd_init_dgram(peer, model, name, fd, 0, NULL, errp);
+    s = net_socket_fd_init_dgram(peer, model, name, fd, errp);
     if (!s) {
         return -1;
     }
 
+    pstrcpy(s->nc.info_str, sizeof(s->nc.info_str), info_str);
+    g_free(info_str);
+
     if (remote) {
         g_assert(s->dgram_dst == NULL);
         s->dgram_dst = dgram_dst;
-
-        pstrcpy(s->nc.info_str, sizeof(s->nc.info_str), info_str);
-        g_free(info_str);
     }
     return 0;
 };
-- 
2.35.3

[RFC PATCH 6/6] net: socket-ng: add unix socket for dgram mode

[Laurent Vivier]

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 net/socket-ng.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 62 insertions(+), 3 deletions(-)

diff --git a/net/socket-ng.c b/net/socket-ng.c
index aabdd0eed381..d4457f4bc63b 100644
--- a/net/socket-ng.c
+++ b/net/socket-ng.c
@@ -123,8 +123,15 @@ static ssize_t net_socket_receive_dgram(NetClientState *nc,
 
     do {
         if (s->dgram_dst) {
-            ret = sendto(s->fd, buf, size, 0, s->dgram_dst,
-                         sizeof(struct sockaddr_in));
+            socklen_t len;
+
+            if (s->dgram_dst->sa_family == AF_INET) {
+                len = sizeof(struct sockaddr_in);
+            } else {
+                len = sizeof(struct sockaddr_un);
+            }
+
+            ret = sendto(s->fd, buf, size, 0, s->dgram_dst, len);
         } else {
             ret = send(s->fd, buf, size, 0);
         }
@@ -831,7 +838,7 @@ static int net_socketng_udp_init(NetClientState *peer,
         }
     } else {
         if (local->type != SOCKET_ADDRESS_TYPE_FD) {
-            error_setg(errp, "type=inet and mode=unicast require "
+            error_setg(errp, "type=inet or unix and mode=unicast require "
                              "remote parameter");
             return -1;
         }
@@ -882,6 +889,58 @@ static int net_socketng_udp_init(NetClientState *peer,
 
         break;
     }
+    case SOCKET_ADDRESS_TYPE_UNIX: {
+        struct sockaddr_un laddr_un, raddr_un;
+
+        ret = unlink(local->u.q_unix.path);
+        if (ret < 0 && errno != ENOENT) {
+            error_setg_errno(errp, errno, "failed to unlink socket %s",
+                             local->u.q_unix.path);
+            return -1;
+        }
+
+        laddr_un.sun_family = PF_UNIX;
+        ret = snprintf(laddr_un.sun_path, sizeof(laddr_un.sun_path), "%s",
+                       local->u.q_unix.path);
+        if (ret < 0 || ret >= sizeof(laddr_un.sun_path)) {
+            error_setg(errp, "UNIX socket path '%s' is too long",
+                       local->u.q_unix.path);
+            error_append_hint(errp, "Path must be less than %zu bytes\n",
+                              sizeof(laddr_un.sun_path));
+        }
+
+        raddr_un.sun_family = PF_UNIX;
+        ret = snprintf(raddr_un.sun_path, sizeof(raddr_un.sun_path), "%s",
+                       remote->u.q_unix.path);
+        if (ret < 0 || ret >= sizeof(raddr_un.sun_path)) {
+            error_setg(errp, "UNIX socket path '%s' is too long",
+                       remote->u.q_unix.path);
+            error_append_hint(errp, "Path must be less than %zu bytes\n",
+                              sizeof(raddr_un.sun_path));
+        }
+
+        fd = qemu_socket(PF_UNIX, SOCK_DGRAM, 0);
+        if (fd < 0) {
+            error_setg_errno(errp, errno, "can't create datagram socket");
+            return -1;
+        }
+
+        ret = bind(fd, (struct sockaddr *)&laddr_un, sizeof(laddr_un));
+        if (ret < 0) {
+            error_setg_errno(errp, errno, "can't bind unix=%s to socket",
+                             laddr_un.sun_path);
+            closesocket(fd);
+            return -1;
+        }
+        qemu_socket_set_nonblock(fd);
+
+        dgram_dst = g_malloc(sizeof(raddr_un));
+        memcpy(dgram_dst, &raddr_un, sizeof(raddr_un));
+
+        info_str = g_strdup_printf("socket-ng: udp=%s:%s",
+                                   laddr_un.sun_path, raddr_un.sun_path);
+        break;
+    }
     case SOCKET_ADDRESS_TYPE_FD: {
         SocketAddress *sa;
         SocketAddressType sa_type;
-- 
2.35.3

Re: [RFC PATCH 0/6] qapi: net: add unix socket type support to netdev backend

[Daniel P. Berrangé]

On Mon, May 09, 2022 at 07:36:12PM +0200, Laurent Vivier wrote:
> "-netdev socket" only supports inet sockets.
> 
> It's not a complex task to add support for unix sockets, but
> the socket netdev parameters are not defined to manage well unix
> socket parameters.
> 
> As discussed in:
> 
>   "socket.c added support for unix domain socket datagram transport"
>   https://lore.kernel.org/qemu-devel/1C0E1BC5-904F-46B0-8044-68E43E67BE60@gmail.com/
> 
> This series adds support of unix socket type using SocketAddress QAPI structure.
> 
> A new netdev backend "socket-ng" is added, that is barely a copy of "socket"
> backend but it uses the SocketAddress QAPI to provide socket parameters.
> And then it also implement unix sockets (TCP and UDP).

So pulling in the QAPI from patch 2

   { 'enum': 'NetdevSocketNGMode',
     'data':  [ 'dgram', 'server', 'client' ] }

   { 'struct': 'NetdevSocketNGOptions',
     'data': {
       'mode':    'NetdevSocketNGMode',
       '*addr':   'SocketAddress',
       '*remote': 'SocketAddress',
       '*local':  'SocketAddress' } }

> Some examples of CLI syntax:
> 
>   for TCP:
> 
>   -netdev socket-ng,id=socket0,mode=server,addr.type=inet,addr.host=localhost,addr.port=1234
>   -netdev socket-ng,id=socket0,mode=client,addr.type=inet,addr.host=localhost,addr.port=1234
> 
>   -netdev socket-ng,id=socket0,mode=dgram,\
>           local.type=inet,local.host=localhost,local.port=1234,\
>           remote.type=inet,remote.host=localhost,remote.port=1235
> 
>   for UNIX:
> 
>   -netdev socket-ng,id=socket0,mode=server,addr.type=unix,addr.path=/tmp/qemu0
>   -netdev socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/qemu0
> 
>   -netdev socket-ng,id=socket0,mode=dgram,\
>           local.type=unix,local.path=/tmp/qemu0,\
>           remote.type=unix,remote.path=/tmp/qemu1
> 
>   for FD:
> 
>   -netdev socket-ng,id=socket0,mode=server,addr.type=fd,addr.str=4
>   -netdev socket-ng,id=socket0,mode=client,addr.type=fd,addr.str=5
> 
>   -netdev socket-ng,id=socket0,mode=dgram,local.type=fd,addr.str=4

                                                          ^^^ local.str=4

I notice that in all these examples, mode=client/server always use
the 'addr' field, and mode=dgram always uses the 'local'/'remote'
fields. IOW, there is almost no commonality between the dgram scenario
and the stream scenario, which feels sub-optimal.

Two alternatives come to mind

 - mode=client could use 'remote' and mode=server could use 'local',
   removing the 'addr' field entirely

 - Have completely separate backends, ie '-netdev stream' for
   client/server TCP/UNIX sockets, and '-netdev dgram' for UDP
   sockets, removing 'mode' field.

I'd have a slight preference for the second, since I'm not thrilled
by the 'socket-ng' name :-) 

With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [RFC PATCH 0/6] qapi: net: add unix socket type support to netdev backend

[Stefano Brivio]

On Tue, 10 May 2022 09:26:39 +0100
Daniel P. Berrangé <berrange@redhat.com> wrote:

> On Mon, May 09, 2022 at 07:36:12PM +0200, Laurent Vivier wrote:
> > "-netdev socket" only supports inet sockets.
> > 
> > It's not a complex task to add support for unix sockets, but
> > the socket netdev parameters are not defined to manage well unix
> > socket parameters.
> > 
> > As discussed in:
> > 
> >   "socket.c added support for unix domain socket datagram transport"
> >   https://lore.kernel.org/qemu-devel/1C0E1BC5-904F-46B0-8044-68E43E67BE60@gmail.com/
> > 
> > This series adds support of unix socket type using SocketAddress QAPI structure.
> > 
> > A new netdev backend "socket-ng" is added, that is barely a copy of "socket"
> > backend but it uses the SocketAddress QAPI to provide socket parameters.
> > And then it also implement unix sockets (TCP and UDP).  
> 
> So pulling in the QAPI from patch 2
> 
>    { 'enum': 'NetdevSocketNGMode',
>      'data':  [ 'dgram', 'server', 'client' ] }
> 
>    { 'struct': 'NetdevSocketNGOptions',
>      'data': {
>        'mode':    'NetdevSocketNGMode',
>        '*addr':   'SocketAddress',
>        '*remote': 'SocketAddress',
>        '*local':  'SocketAddress' } }
> 
> > Some examples of CLI syntax:
> > 
> >   for TCP:
> > 
> >   -netdev socket-ng,id=socket0,mode=server,addr.type=inet,addr.host=localhost,addr.port=1234
> >   -netdev socket-ng,id=socket0,mode=client,addr.type=inet,addr.host=localhost,addr.port=1234
> > 
> >   -netdev socket-ng,id=socket0,mode=dgram,\
> >           local.type=inet,local.host=localhost,local.port=1234,\
> >           remote.type=inet,remote.host=localhost,remote.port=1235
> > 
> >   for UNIX:
> > 
> >   -netdev socket-ng,id=socket0,mode=server,addr.type=unix,addr.path=/tmp/qemu0
> >   -netdev socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/qemu0
> > 
> >   -netdev socket-ng,id=socket0,mode=dgram,\
> >           local.type=unix,local.path=/tmp/qemu0,\
> >           remote.type=unix,remote.path=/tmp/qemu1
> > 
> >   for FD:
> > 
> >   -netdev socket-ng,id=socket0,mode=server,addr.type=fd,addr.str=4
> >   -netdev socket-ng,id=socket0,mode=client,addr.type=fd,addr.str=5
> > 
> >   -netdev socket-ng,id=socket0,mode=dgram,local.type=fd,addr.str=4  
> 
>                                                           ^^^ local.str=4
> 
> I notice that in all these examples, mode=client/server always use
> the 'addr' field, and mode=dgram always uses the 'local'/'remote'
> fields. IOW, there is almost no commonality between the dgram scenario
> and the stream scenario, which feels sub-optimal.
> 
> Two alternatives come to mind
> 
>  - mode=client could use 'remote' and mode=server could use 'local',
>    removing the 'addr' field entirely

To me, "mode is client, address is x" sounds more intuitive than "mode
is client, remote is x". I mean, of course it's the remote address --
that's a bit redundant.

>  - Have completely separate backends, ie '-netdev stream' for
>    client/server TCP/UNIX sockets, and '-netdev dgram' for UDP
>    sockets, removing 'mode' field.

...this won't work, though, because UNIX domain sockets can be
stream-oriented or datagram-oriented.

-- 
Stefano

Re: [RFC PATCH 0/6] qapi: net: add unix socket type support to netdev backend

[Daniel P. Berrangé]

On Tue, May 10, 2022 at 10:59:08AM +0200, Stefano Brivio wrote:
> On Tue, 10 May 2022 09:26:39 +0100
> Daniel P. Berrangé <berrange@redhat.com> wrote:
> 
> > On Mon, May 09, 2022 at 07:36:12PM +0200, Laurent Vivier wrote:
> > > "-netdev socket" only supports inet sockets.
> > > 
> > > It's not a complex task to add support for unix sockets, but
> > > the socket netdev parameters are not defined to manage well unix
> > > socket parameters.
> > > 
> > > As discussed in:
> > > 
> > >   "socket.c added support for unix domain socket datagram transport"
> > >   https://lore.kernel.org/qemu-devel/1C0E1BC5-904F-46B0-8044-68E43E67BE60@gmail.com/
> > > 
> > > This series adds support of unix socket type using SocketAddress QAPI structure.
> > > 
> > > A new netdev backend "socket-ng" is added, that is barely a copy of "socket"
> > > backend but it uses the SocketAddress QAPI to provide socket parameters.
> > > And then it also implement unix sockets (TCP and UDP).  
> > 
> > So pulling in the QAPI from patch 2
> > 
> >    { 'enum': 'NetdevSocketNGMode',
> >      'data':  [ 'dgram', 'server', 'client' ] }
> > 
> >    { 'struct': 'NetdevSocketNGOptions',
> >      'data': {
> >        'mode':    'NetdevSocketNGMode',
> >        '*addr':   'SocketAddress',
> >        '*remote': 'SocketAddress',
> >        '*local':  'SocketAddress' } }
> > 
> > > Some examples of CLI syntax:
> > > 
> > >   for TCP:
> > > 
> > >   -netdev socket-ng,id=socket0,mode=server,addr.type=inet,addr.host=localhost,addr.port=1234
> > >   -netdev socket-ng,id=socket0,mode=client,addr.type=inet,addr.host=localhost,addr.port=1234
> > > 
> > >   -netdev socket-ng,id=socket0,mode=dgram,\
> > >           local.type=inet,local.host=localhost,local.port=1234,\
> > >           remote.type=inet,remote.host=localhost,remote.port=1235
> > > 
> > >   for UNIX:
> > > 
> > >   -netdev socket-ng,id=socket0,mode=server,addr.type=unix,addr.path=/tmp/qemu0
> > >   -netdev socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/qemu0
> > > 
> > >   -netdev socket-ng,id=socket0,mode=dgram,\
> > >           local.type=unix,local.path=/tmp/qemu0,\
> > >           remote.type=unix,remote.path=/tmp/qemu1
> > > 
> > >   for FD:
> > > 
> > >   -netdev socket-ng,id=socket0,mode=server,addr.type=fd,addr.str=4
> > >   -netdev socket-ng,id=socket0,mode=client,addr.type=fd,addr.str=5
> > > 
> > >   -netdev socket-ng,id=socket0,mode=dgram,local.type=fd,addr.str=4  
> > 
> >                                                           ^^^ local.str=4
> > 
> > I notice that in all these examples, mode=client/server always use
> > the 'addr' field, and mode=dgram always uses the 'local'/'remote'
> > fields. IOW, there is almost no commonality between the dgram scenario
> > and the stream scenario, which feels sub-optimal.
> > 
> > Two alternatives come to mind
> > 
> >  - mode=client could use 'remote' and mode=server could use 'local',
> >    removing the 'addr' field entirely
> 
> To me, "mode is client, address is x" sounds more intuitive than "mode
> is client, remote is x". I mean, of course it's the remote address --
> that's a bit redundant.
> 
> >  - Have completely separate backends, ie '-netdev stream' for
> >    client/server TCP/UNIX sockets, and '-netdev dgram' for UDP
> >    sockets, removing 'mode' field.
> 
> ...this won't work, though, because UNIX domain sockets can be
> stream-oriented or datagram-oriented.

Sure it can work, both the 'stream' and 'dgram' backends would
allow the full range of addr types as they're independant config
dimensions


    -netdev stream,server=no,addr.type=inet,addr.host=localhost,addr.port=1234
    -netdev stream,server=no,addr.type=unix,addr.path=/some/stream/sock


    -netdev dgram,id=ndev0,\
            local.type=inet,local.host=localhost,local.port=1234,\
            remote.type=inet,remote.host=localhost,remote.port=1235
    -netdev dgram,id=ndev0,\
            local.type=unix,local.path=/some/dgram/sock0,
            remote.type=unix,remote.path=/some/dgram/sock1


With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [RFC PATCH 0/6] qapi: net: add unix socket type support to netdev backend

[Stefano Brivio]

On Tue, 10 May 2022 10:22:48 +0100
Daniel P. Berrangé <berrange@redhat.com> wrote:

> On Tue, May 10, 2022 at 10:59:08AM +0200, Stefano Brivio wrote:
> > On Tue, 10 May 2022 09:26:39 +0100
> > Daniel P. Berrangé <berrange@redhat.com> wrote:
> >   
> > > On Mon, May 09, 2022 at 07:36:12PM +0200, Laurent Vivier wrote:  
> > > > "-netdev socket" only supports inet sockets.
> > > > 
> > > > It's not a complex task to add support for unix sockets, but
> > > > the socket netdev parameters are not defined to manage well unix
> > > > socket parameters.
> > > > 
> > > > As discussed in:
> > > > 
> > > >   "socket.c added support for unix domain socket datagram transport"
> > > >   https://lore.kernel.org/qemu-devel/1C0E1BC5-904F-46B0-8044-68E43E67BE60@gmail.com/
> > > > 
> > > > This series adds support of unix socket type using SocketAddress QAPI structure.
> > > > 
> > > > A new netdev backend "socket-ng" is added, that is barely a copy of "socket"
> > > > backend but it uses the SocketAddress QAPI to provide socket parameters.
> > > > And then it also implement unix sockets (TCP and UDP).    
> > > 
> > > So pulling in the QAPI from patch 2
> > > 
> > >    { 'enum': 'NetdevSocketNGMode',
> > >      'data':  [ 'dgram', 'server', 'client' ] }
> > > 
> > >    { 'struct': 'NetdevSocketNGOptions',
> > >      'data': {
> > >        'mode':    'NetdevSocketNGMode',
> > >        '*addr':   'SocketAddress',
> > >        '*remote': 'SocketAddress',
> > >        '*local':  'SocketAddress' } }
> > >   
> > > > Some examples of CLI syntax:
> > > > 
> > > >   for TCP:
> > > > 
> > > >   -netdev socket-ng,id=socket0,mode=server,addr.type=inet,addr.host=localhost,addr.port=1234
> > > >   -netdev socket-ng,id=socket0,mode=client,addr.type=inet,addr.host=localhost,addr.port=1234
> > > > 
> > > >   -netdev socket-ng,id=socket0,mode=dgram,\
> > > >           local.type=inet,local.host=localhost,local.port=1234,\
> > > >           remote.type=inet,remote.host=localhost,remote.port=1235
> > > > 
> > > >   for UNIX:
> > > > 
> > > >   -netdev socket-ng,id=socket0,mode=server,addr.type=unix,addr.path=/tmp/qemu0
> > > >   -netdev socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/qemu0
> > > > 
> > > >   -netdev socket-ng,id=socket0,mode=dgram,\
> > > >           local.type=unix,local.path=/tmp/qemu0,\
> > > >           remote.type=unix,remote.path=/tmp/qemu1
> > > > 
> > > >   for FD:
> > > > 
> > > >   -netdev socket-ng,id=socket0,mode=server,addr.type=fd,addr.str=4
> > > >   -netdev socket-ng,id=socket0,mode=client,addr.type=fd,addr.str=5
> > > > 
> > > >   -netdev socket-ng,id=socket0,mode=dgram,local.type=fd,addr.str=4    
> > > 
> > >                                                           ^^^ local.str=4
> > > 
> > > I notice that in all these examples, mode=client/server always use
> > > the 'addr' field, and mode=dgram always uses the 'local'/'remote'
> > > fields. IOW, there is almost no commonality between the dgram scenario
> > > and the stream scenario, which feels sub-optimal.
> > > 
> > > Two alternatives come to mind
> > > 
> > >  - mode=client could use 'remote' and mode=server could use 'local',
> > >    removing the 'addr' field entirely  
> > 
> > To me, "mode is client, address is x" sounds more intuitive than "mode
> > is client, remote is x". I mean, of course it's the remote address --
> > that's a bit redundant.
> >   
> > >  - Have completely separate backends, ie '-netdev stream' for
> > >    client/server TCP/UNIX sockets, and '-netdev dgram' for UDP
> > >    sockets, removing 'mode' field.  

Well, this ^^^ is one thing ('-netdev stream' for UNIX sockets),

> > ...this won't work, though, because UNIX domain sockets can be
> > stream-oriented or datagram-oriented.  
> 
> Sure it can work, both the 'stream' and 'dgram' backends would
> allow the full range of addr types as they're independant config
> dimensions
> 
> 
>     -netdev stream,server=no,addr.type=inet,addr.host=localhost,addr.port=1234
>     -netdev stream,server=no,addr.type=unix,addr.path=/some/stream/sock
> 
> 
>     -netdev dgram,id=ndev0,\
>             local.type=inet,local.host=localhost,local.port=1234,\
>             remote.type=inet,remote.host=localhost,remote.port=1235
>     -netdev dgram,id=ndev0,\
>             local.type=unix,local.path=/some/dgram/sock0,
>             remote.type=unix,remote.path=/some/dgram/sock1

...and this ('-netdev dgram' for UNIX sockets) is another one. :)

Indeed they're independent though, so I also prefer this version (with
the details Laurent just provided).

-- 
Stefano

Re: [RFC PATCH 0/6] qapi: net: add unix socket type support to netdev backend

[Ralph Schmieder]

[-- Attachment #1: Type: text/plain, Size: 4901 bytes --]

This looks very promising to me as it provides the flexibility needed for
all the permutations.  Thanks for looking into it!

On Tue, May 10, 2022 at 11:22 AM Daniel P. Berrangé <berrange@redhat.com>
wrote:

> On Tue, May 10, 2022 at 10:59:08AM +0200, Stefano Brivio wrote:
> > On Tue, 10 May 2022 09:26:39 +0100
> > Daniel P. Berrangé <berrange@redhat.com> wrote:
> >
> > > On Mon, May 09, 2022 at 07:36:12PM +0200, Laurent Vivier wrote:
> > > > "-netdev socket" only supports inet sockets.
> > > >
> > > > It's not a complex task to add support for unix sockets, but
> > > > the socket netdev parameters are not defined to manage well unix
> > > > socket parameters.
> > > >
> > > > As discussed in:
> > > >
> > > >   "socket.c added support for unix domain socket datagram transport"
> > > >
> https://lore.kernel.org/qemu-devel/1C0E1BC5-904F-46B0-8044-68E43E67BE60@gmail.com/
> > > >
> > > > This series adds support of unix socket type using SocketAddress
> QAPI structure.
> > > >
> > > > A new netdev backend "socket-ng" is added, that is barely a copy of
> "socket"
> > > > backend but it uses the SocketAddress QAPI to provide socket
> parameters.
> > > > And then it also implement unix sockets (TCP and UDP).
> > >
> > > So pulling in the QAPI from patch 2
> > >
> > >    { 'enum': 'NetdevSocketNGMode',
> > >      'data':  [ 'dgram', 'server', 'client' ] }
> > >
> > >    { 'struct': 'NetdevSocketNGOptions',
> > >      'data': {
> > >        'mode':    'NetdevSocketNGMode',
> > >        '*addr':   'SocketAddress',
> > >        '*remote': 'SocketAddress',
> > >        '*local':  'SocketAddress' } }
> > >
> > > > Some examples of CLI syntax:
> > > >
> > > >   for TCP:
> > > >
> > > >   -netdev
> socket-ng,id=socket0,mode=server,addr.type=inet,addr.host=localhost,addr.port=1234
> > > >   -netdev
> socket-ng,id=socket0,mode=client,addr.type=inet,addr.host=localhost,addr.port=1234
> > > >
> > > >   -netdev socket-ng,id=socket0,mode=dgram,\
> > > >           local.type=inet,local.host=localhost,local.port=1234,\
> > > >           remote.type=inet,remote.host=localhost,remote.port=1235
> > > >
> > > >   for UNIX:
> > > >
> > > >   -netdev
> socket-ng,id=socket0,mode=server,addr.type=unix,addr.path=/tmp/qemu0
> > > >   -netdev
> socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/qemu0
> > > >
> > > >   -netdev socket-ng,id=socket0,mode=dgram,\
> > > >           local.type=unix,local.path=/tmp/qemu0,\
> > > >           remote.type=unix,remote.path=/tmp/qemu1
> > > >
> > > >   for FD:
> > > >
> > > >   -netdev socket-ng,id=socket0,mode=server,addr.type=fd,addr.str=4
> > > >   -netdev socket-ng,id=socket0,mode=client,addr.type=fd,addr.str=5
> > > >
> > > >   -netdev socket-ng,id=socket0,mode=dgram,local.type=fd,addr.str=4
> > >
> > >                                                           ^^^
> local.str=4
> > >
> > > I notice that in all these examples, mode=client/server always use
> > > the 'addr' field, and mode=dgram always uses the 'local'/'remote'
> > > fields. IOW, there is almost no commonality between the dgram scenario
> > > and the stream scenario, which feels sub-optimal.
> > >
> > > Two alternatives come to mind
> > >
> > >  - mode=client could use 'remote' and mode=server could use 'local',
> > >    removing the 'addr' field entirely
> >
> > To me, "mode is client, address is x" sounds more intuitive than "mode
> > is client, remote is x". I mean, of course it's the remote address --
> > that's a bit redundant.
> >
> > >  - Have completely separate backends, ie '-netdev stream' for
> > >    client/server TCP/UNIX sockets, and '-netdev dgram' for UDP
> > >    sockets, removing 'mode' field.
> >
> > ...this won't work, though, because UNIX domain sockets can be
> > stream-oriented or datagram-oriented.
>
> Sure it can work, both the 'stream' and 'dgram' backends would
> allow the full range of addr types as they're independant config
> dimensions
>
>
>     -netdev
> stream,server=no,addr.type=inet,addr.host=localhost,addr.port=1234
>     -netdev stream,server=no,addr.type=unix,addr.path=/some/stream/sock
>
>
>     -netdev dgram,id=ndev0,\
>             local.type=inet,local.host=localhost,local.port=1234,\
>             remote.type=inet,remote.host=localhost,remote.port=1235
>     -netdev dgram,id=ndev0,\
>             local.type=unix,local.path=/some/dgram/sock0,
>             remote.type=unix,remote.path=/some/dgram/sock1
>
>
> With regards,
> Daniel
> --
> |: https://berrange.com      -o-
> https://www.flickr.com/photos/dberrange :|
> |: https://libvirt.org         -o-
> https://fstop138.berrange.com :|
> |: https://entangle-photo.org    -o-
> https://www.instagram.com/dberrange :|
>
>

-- 
Ralph Schmieder
Holtzstr. 2
76135 Karlsruhe
Germany
ralph.schmieder@gmail.com

[-- Attachment #2: Type: text/html, Size: 7266 bytes --]

Re: [RFC PATCH 0/6] qapi: net: add unix socket type support to netdev backend

[Laurent Vivier]

On 10/05/2022 10:26, Daniel P. Berrangé wrote:
> On Mon, May 09, 2022 at 07:36:12PM +0200, Laurent Vivier wrote:
>> "-netdev socket" only supports inet sockets.
>>
>> It's not a complex task to add support for unix sockets, but
>> the socket netdev parameters are not defined to manage well unix
>> socket parameters.
>>
>> As discussed in:
>>
>>    "socket.c added support for unix domain socket datagram transport"
>>    https://lore.kernel.org/qemu-devel/1C0E1BC5-904F-46B0-8044-68E43E67BE60@gmail.com/
>>
>> This series adds support of unix socket type using SocketAddress QAPI structure.
>>
>> A new netdev backend "socket-ng" is added, that is barely a copy of "socket"
>> backend but it uses the SocketAddress QAPI to provide socket parameters.
>> And then it also implement unix sockets (TCP and UDP).
> 
> So pulling in the QAPI from patch 2
> 
>     { 'enum': 'NetdevSocketNGMode',
>       'data':  [ 'dgram', 'server', 'client' ] }
> 
>     { 'struct': 'NetdevSocketNGOptions',
>       'data': {
>         'mode':    'NetdevSocketNGMode',
>         '*addr':   'SocketAddress',
>         '*remote': 'SocketAddress',
>         '*local':  'SocketAddress' } }
> 
>> Some examples of CLI syntax:
>>
>>    for TCP:
>>
>>    -netdev socket-ng,id=socket0,mode=server,addr.type=inet,addr.host=localhost,addr.port=1234
>>    -netdev socket-ng,id=socket0,mode=client,addr.type=inet,addr.host=localhost,addr.port=1234
>>
>>    -netdev socket-ng,id=socket0,mode=dgram,\
>>            local.type=inet,local.host=localhost,local.port=1234,\
>>            remote.type=inet,remote.host=localhost,remote.port=1235
>>
>>    for UNIX:
>>
>>    -netdev socket-ng,id=socket0,mode=server,addr.type=unix,addr.path=/tmp/qemu0
>>    -netdev socket-ng,id=socket0,mode=client,addr.type=unix,addr.path=/tmp/qemu0
>>
>>    -netdev socket-ng,id=socket0,mode=dgram,\
>>            local.type=unix,local.path=/tmp/qemu0,\
>>            remote.type=unix,remote.path=/tmp/qemu1
>>
>>    for FD:
>>
>>    -netdev socket-ng,id=socket0,mode=server,addr.type=fd,addr.str=4
>>    -netdev socket-ng,id=socket0,mode=client,addr.type=fd,addr.str=5
>>
>>    -netdev socket-ng,id=socket0,mode=dgram,local.type=fd,addr.str=4
> 
>                                                            ^^^ local.str=4
> 
> I notice that in all these examples, mode=client/server always use
> the 'addr' field, and mode=dgram always uses the 'local'/'remote'
> fields. IOW, there is almost no commonality between the dgram scenario
> and the stream scenario, which feels sub-optimal.
> 
> Two alternatives come to mind
> 
>   - mode=client could use 'remote' and mode=server could use 'local',
>     removing the 'addr' field entirely
> 
>   - Have completely separate backends, ie '-netdev stream' for
>     client/server TCP/UNIX sockets, and '-netdev dgram' for UDP
>     sockets, removing 'mode' field.
> 
> I'd have a slight preference for the second, since I'm not thrilled
> by the 'socket-ng' name :-)

It seems reasonable, I'm going to update my series in this way:

    { 'struct': 'NetdevStreamOptions',
      'data': {
        'addr':   'SocketAddress' } }

    { 'struct': 'NetdevDgramOptions',
      'data': {
       '*local':   'SocketAddress',
       '*remote':   'SocketAddress' } }

Both parameters are optional because:
multicast needs 'remote' for the multicast address and optionally a local for source 
address or fd.
unicast needs both, except for fd where local provides fd and remote is needed only if 
local is not an fd.

    { 'union': 'Netdev',
      'base': { 'id': 'str', 'type': 'NetClientDriver' },
      'discriminator': 'type',
      'data': {
      ...
      'stream': 'NetdevStreamOptions',
      'dgram': 'NetdevDgramOptions' } }

Thanks,
Laurent