[RFC PATCH v2 0/8] qapi: net: add unix socket type support to netdev backend

[RFC PATCH v2 0/8] 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.

Two new netdev backends, "stream" and "dgram" are added, that are barely a copy of "socket"
backend but they use the SocketAddress QAPI to provide socket parameters.
And then they also implement unix sockets (TCP and UDP).

Some examples of CLI syntax:

  for TCP:

  -netdev stream,id=socket0,addr.type=inet,addr.host=localhost,addr.port=1234
  -netdev stream,id=socket0,server=off,addr.type=inet,addr.host=localhost,addr.port=1234

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

  for UNIX:

  -netdev stream,id=socket0,addr.type=unix,addr.path=/tmp/qemu0
  -netdev stream,id=socket0,server=off,addr.type=unix,addr.path=/tmp/qemu0

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

  for FD:

  -netdev stream,id=socket0,addr.type=fd,addr.str=4
  -netdev stream,id=socket0,server=off,addr.type=fd,addr.str=5

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

v2:
  - use "stream" and "dgram" rather than "socket-ng,mode=stream"
    and ""socket-ng,mode=dgram"
  - extract code to bypass qemu_opts_parse_noisily() to
    a new patch
  - do not ignore EINVAL (Stefano)
  - fix "-net" option

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 (7):
  net: introduce convert_host_port()
  qapi: net: introduce a way to bypass qemu_opts_parse_noisily()
  qapi: net: add stream and dgram netdevs
  net: stream: add unix socket
  net: dgram: make dgram_dst generic
  net: dgram: move mcast specific code from net_socket_fd_init_dgram()
  net: dgram: add unix socket

Stefano Brivio (1):
  net: stream: Don't ignore EINVAL on netdev socket connection

 hmp-commands.hx        |   2 +-
 include/qemu/sockets.h |   2 +
 net/clients.h          |   6 +
 net/dgram.c            | 706 +++++++++++++++++++++++++++++++++++++++++
 net/hub.c              |   2 +
 net/meson.build        |   2 +
 net/net.c              | 138 ++++++--
 net/stream.c           | 516 ++++++++++++++++++++++++++++++
 qapi/net.json          |  38 ++-
 9 files changed, 1379 insertions(+), 33 deletions(-)
 create mode 100644 net/dgram.c
 create mode 100644 net/stream.c

-- 
2.35.3

[RFC PATCH v2 1/8] 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

[RFC PATCH v2 2/8] qapi: net: introduce a way to bypass qemu_opts_parse_noisily()

[Laurent Vivier]

As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field
of Netdev structure can collides with "type" field of SocketAddress),
we introduce a way to bypass qemu_opts_parse_noisily() and use directly
visit_type_Netdev() to parse the backend parameters.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 net/net.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/net/net.c b/net/net.c
index 58c05c200622..2aab7167316c 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 +64,17 @@
 static VMChangeStateEntry *net_change_state_entry;
 static QTAILQ_HEAD(, NetClientState) net_clients;
 
+typedef struct NetdevQueueEntry {
+    bool is_netdev;
+    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 */
 
@@ -1559,6 +1571,19 @@ 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, nd->is_netdev, 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 +1600,37 @@ int net_init_clients(Error **errp)
     return 0;
 }
 
+/*
+ * netdev_is_modern() returns true when the backend needs to bypass
+ * qemu_opts_parse_noisily()
+ */
+static bool netdev_is_modern(const char *optarg)
+{
+    return false;
+}
+
 int net_client_parse(QemuOptsList *opts_list, const char *optarg)
 {
+    if (netdev_is_modern(optarg)) {
+            /*
+             * We need to bypass qemu_opts_parse_noisily() to accept
+             * new style object like addr.type=inet in SocketAddress
+             */
+            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);
+            nd->is_netdev = strcmp(opts_list->name, "netdev") == 0;
+
+            QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry);
+            return 0;
+    }
+
     if (!qemu_opts_parse_noisily(opts_list, optarg, true)) {
         return -1;
     }
-- 
2.35.3

Re: [RFC PATCH v2 2/8] qapi: net: introduce a way to bypass qemu_opts_parse_noisily()

[Markus Armbruster]

Laurent Vivier <lvivier@redhat.com> writes:

> As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field
> of Netdev structure can collides with "type" field of SocketAddress),

To remember how this works, I have to write a more verbose version of
the above.  Why not post it then, so here goes.

qemu_init() passes the argument of -netdev, -nic, and -net to
net_client_parse().

net_client_parse() parses with qemu_opts_parse_noisily(), passing
QemuOptsList qemu_netdev_opts for -netdev, qemu_nic_opts for -nic, and
qemu_net_opts for -net.  Their desc[] are all empty, which means any
keys are accepted.  The result of the parse (a QemuOpts) is stored in
the QemuOptsList.

Note that QemuOpts is flat by design.  In some places, we layer non-flat
on top using dotted keys convention, but not here.

net_init_clients() iterates over the stored QemuOpts, and passes them to
net_init_netdev(), net_param_nic(), or net_init_client(), respectively.

These functions pass the QemuOpts to net_client_init().  They also do
other things with the QemuOpts, which we can ignore here.

net_client_init() uses the opts visitor to convert the (flat) QemOpts to
a (non-flat) QAPI object Netdev.  Netdev is also the argument of QMP
command netdev_add.

The opts visitor was an early attempt to support QAPI in
(QemuOpts-based) CLI.  It restricts QAPI types to a certain shape; see
commit eb7ee2cbeb "qapi: introduce OptsVisitor".

A more modern way to support QAPI is qobject_input_visitor_new_str().
It uses keyval_parse() instead of QemuOpts for KEY=VALUE,... syntax, and
it also supports JSON syntax.  The former isn't quite as expressive as
JSON, but it's a lot closer than QemuOpts + opts visitor.

> we introduce a way to bypass qemu_opts_parse_noisily() and use directly
> visit_type_Netdev() to parse the backend parameters.

This commit paves the way to use of the modern way instead.

> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  net/net.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 54 insertions(+)
>
> diff --git a/net/net.c b/net/net.c
> index 58c05c200622..2aab7167316c 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 +64,17 @@
>  static VMChangeStateEntry *net_change_state_entry;
>  static QTAILQ_HEAD(, NetClientState) net_clients;
>  
> +typedef struct NetdevQueueEntry {
> +    bool is_netdev;
> +    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 */
>  
> @@ -1559,6 +1571,19 @@ 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, nd->is_netdev, errp) < 0) {

I think you need to loc_pop() here.

> +            return -1;
> +        }

Since the only caller passes &error_fatal, I'd be tempted to ditch the
@errp argument, and simply do

           net_client_init1(nd->nd, nd->is_netdev, &error_fatal);

It's what we do for -blockdev, -device, and -object.

> +        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 +1600,37 @@ int net_init_clients(Error **errp)
>      return 0;
>  }
>  
> +/*
> + * netdev_is_modern() returns true when the backend needs to bypass
> + * qemu_opts_parse_noisily()
> + */
> +static bool netdev_is_modern(const char *optarg)
> +{
> +    return false;
> +}
> +
>  int net_client_parse(QemuOptsList *opts_list, const char *optarg)
>  {
> +    if (netdev_is_modern(optarg)) {
> +            /*
> +             * We need to bypass qemu_opts_parse_noisily() to accept
> +             * new style object like addr.type=inet in SocketAddress
> +             */

I'm not sure this will makes sense to future readers.

What about "Use modern, more expressive syntax"?

> +            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);
> +            nd->is_netdev = strcmp(opts_list->name, "netdev") == 0;
> +
> +            QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry);
> +            return 0;
> +    }

Matches what we do for -blockdev, except we additionally have
nd->is_netdev.  We need it for calling net_client_init1().

If netdev_is_modern(optarg), then the only use of parameter @opts_list
is opts_list->name in the initialization of nd->is_netdev.

There's a bit of code smell, I'm afraid.

I believe @is_netdev needs to be true for -netdev, -nic, and netdev_add;
false for -net.

Will we ever use the modern syntax with -net?

Any chance we can deprecate -net?

> +
>      if (!qemu_opts_parse_noisily(opts_list, optarg, true)) {
>          return -1;
>      }

Re: [RFC PATCH v2 2/8] qapi: net: introduce a way to bypass qemu_opts_parse_noisily()

[Laurent Vivier]

On 13/05/2022 13:21, Markus Armbruster wrote:
> Laurent Vivier <lvivier@redhat.com> writes:
> 
>> As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field
>> of Netdev structure can collides with "type" field of SocketAddress),
> 
> To remember how this works, I have to write a more verbose version of
> the above.  Why not post it then, so here goes.
> 
> qemu_init() passes the argument of -netdev, -nic, and -net to
> net_client_parse().
> 
> net_client_parse() parses with qemu_opts_parse_noisily(), passing
> QemuOptsList qemu_netdev_opts for -netdev, qemu_nic_opts for -nic, and
> qemu_net_opts for -net.  Their desc[] are all empty, which means any
> keys are accepted.  The result of the parse (a QemuOpts) is stored in
> the QemuOptsList.
> 
> Note that QemuOpts is flat by design.  In some places, we layer non-flat
> on top using dotted keys convention, but not here.
> 
> net_init_clients() iterates over the stored QemuOpts, and passes them to
> net_init_netdev(), net_param_nic(), or net_init_client(), respectively.
> 
> These functions pass the QemuOpts to net_client_init().  They also do
> other things with the QemuOpts, which we can ignore here.
> 
> net_client_init() uses the opts visitor to convert the (flat) QemOpts to
> a (non-flat) QAPI object Netdev.  Netdev is also the argument of QMP
> command netdev_add.
> 
> The opts visitor was an early attempt to support QAPI in
> (QemuOpts-based) CLI.  It restricts QAPI types to a certain shape; see
> commit eb7ee2cbeb "qapi: introduce OptsVisitor".
> 
> A more modern way to support QAPI is qobject_input_visitor_new_str().
> It uses keyval_parse() instead of QemuOpts for KEY=VALUE,... syntax, and
> it also supports JSON syntax.  The former isn't quite as expressive as
> JSON, but it's a lot closer than QemuOpts + opts visitor.
> 
>> we introduce a way to bypass qemu_opts_parse_noisily() and use directly
>> visit_type_Netdev() to parse the backend parameters.
> 
> This commit paves the way to use of the modern way instead.

I'm going to copy your analysis to the commit message of the patch.

> 
>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>> ---
>>   net/net.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 54 insertions(+)
>>
>> diff --git a/net/net.c b/net/net.c
>> index 58c05c200622..2aab7167316c 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 +64,17 @@
>>   static VMChangeStateEntry *net_change_state_entry;
>>   static QTAILQ_HEAD(, NetClientState) net_clients;
>>   
>> +typedef struct NetdevQueueEntry {
>> +    bool is_netdev;
>> +    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 */
>>   
>> @@ -1559,6 +1571,19 @@ 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, nd->is_netdev, errp) < 0) {
> 
> I think you need to loc_pop() here.
> 
>> +            return -1;
>> +        }
> 
> Since the only caller passes &error_fatal, I'd be tempted to ditch the
> @errp argument, and simply do
> 
>             net_client_init1(nd->nd, nd->is_netdev, &error_fatal);
> 
> It's what we do for -blockdev, -device, and -object.

I've added a patch to remove the @errp from the net_init_clients() arguments.

> 
>> +        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 +1600,37 @@ int net_init_clients(Error **errp)
>>       return 0;
>>   }
>>   
>> +/*
>> + * netdev_is_modern() returns true when the backend needs to bypass
>> + * qemu_opts_parse_noisily()
>> + */
>> +static bool netdev_is_modern(const char *optarg)
>> +{
>> +    return false;
>> +}
>> +
>>   int net_client_parse(QemuOptsList *opts_list, const char *optarg)
>>   {
>> +    if (netdev_is_modern(optarg)) {
>> +            /*
>> +             * We need to bypass qemu_opts_parse_noisily() to accept
>> +             * new style object like addr.type=inet in SocketAddress
>> +             */
> 
> I'm not sure this will makes sense to future readers.
> 
> What about "Use modern, more expressive syntax"?

Done.

> 
>> +            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);
>> +            nd->is_netdev = strcmp(opts_list->name, "netdev") == 0;
>> +
>> +            QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry);
>> +            return 0;
>> +    }
> 
> Matches what we do for -blockdev, except we additionally have
> nd->is_netdev.  We need it for calling net_client_init1().
> 
> If netdev_is_modern(optarg), then the only use of parameter @opts_list
> is opts_list->name in the initialization of nd->is_netdev.
> 
> There's a bit of code smell, I'm afraid.

I don't see what is the problem.

> 
> I believe @is_netdev needs to be true for -netdev, -nic, and netdev_add;
> false for -net.
> 
> Will we ever use the modern syntax with -net?

Yes, I think we should support the same syntax with -netdev and -net.

My first iteration was to pass is_netdev=true to net_client_init1() and Stefano reported a 
problem with "-net" with things like that:

     -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

> 
> Any chance we can deprecate -net?

Who can decide of that?

> 
>> +
>>       if (!qemu_opts_parse_noisily(opts_list, optarg, true)) {
>>           return -1;
>>       }
> 

Thanks,
Laurent

Re: [RFC PATCH v2 2/8] qapi: net: introduce a way to bypass qemu_opts_parse_noisily()

[Markus Armbruster]

Laurent Vivier <lvivier@redhat.com> writes:

> On 13/05/2022 13:21, Markus Armbruster wrote:
>> Laurent Vivier <lvivier@redhat.com> writes:
>> 
>>> As qemu_opts_parse_noisily() flattens the QAPI structures ("type" field
>>> of Netdev structure can collides with "type" field of SocketAddress),
>> 
>> To remember how this works, I have to write a more verbose version of
>> the above.  Why not post it then, so here goes.
>> 
>> qemu_init() passes the argument of -netdev, -nic, and -net to
>> net_client_parse().
>> 
>> net_client_parse() parses with qemu_opts_parse_noisily(), passing
>> QemuOptsList qemu_netdev_opts for -netdev, qemu_nic_opts for -nic, and
>> qemu_net_opts for -net.  Their desc[] are all empty, which means any
>> keys are accepted.  The result of the parse (a QemuOpts) is stored in
>> the QemuOptsList.
>> 
>> Note that QemuOpts is flat by design.  In some places, we layer non-flat
>> on top using dotted keys convention, but not here.
>> 
>> net_init_clients() iterates over the stored QemuOpts, and passes them to
>> net_init_netdev(), net_param_nic(), or net_init_client(), respectively.
>> 
>> These functions pass the QemuOpts to net_client_init().  They also do
>> other things with the QemuOpts, which we can ignore here.
>> 
>> net_client_init() uses the opts visitor to convert the (flat) QemOpts to
>> a (non-flat) QAPI object Netdev.  Netdev is also the argument of QMP
>> command netdev_add.
>> 
>> The opts visitor was an early attempt to support QAPI in
>> (QemuOpts-based) CLI.  It restricts QAPI types to a certain shape; see
>> commit eb7ee2cbeb "qapi: introduce OptsVisitor".
>> 
>> A more modern way to support QAPI is qobject_input_visitor_new_str().
>> It uses keyval_parse() instead of QemuOpts for KEY=VALUE,... syntax, and
>> it also supports JSON syntax.  The former isn't quite as expressive as
>> JSON, but it's a lot closer than QemuOpts + opts visitor.
>> 
>>> we introduce a way to bypass qemu_opts_parse_noisily() and use directly
>>> visit_type_Netdev() to parse the backend parameters.
>> 
>> This commit paves the way to use of the modern way instead.
>
> I'm going to copy your analysis to the commit message of the patch.

Go right ahead :)

>>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>>> ---
>>>   net/net.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>   1 file changed, 54 insertions(+)
>>>
>>> diff --git a/net/net.c b/net/net.c
>>> index 58c05c200622..2aab7167316c 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 +64,17 @@
>>>   static VMChangeStateEntry *net_change_state_entry;
>>>   static QTAILQ_HEAD(, NetClientState) net_clients;
>>>   
>>> +typedef struct NetdevQueueEntry {
>>> +    bool is_netdev;
>>> +    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 */
>>>   
>>> @@ -1559,6 +1571,19 @@ 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, nd->is_netdev, errp) < 0) {
>> 
>> I think you need to loc_pop() here.
>> 
>>> +            return -1;
>>> +        }
>> 
>> Since the only caller passes &error_fatal, I'd be tempted to ditch the
>> @errp argument, and simply do
>> 
>>             net_client_init1(nd->nd, nd->is_netdev, &error_fatal);
>> 
>> It's what we do for -blockdev, -device, and -object.
>
> I've added a patch to remove the @errp from the net_init_clients() arguments.
>
>> 
>>> +        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 +1600,37 @@ int net_init_clients(Error **errp)
>>>       return 0;
>>>   }
>>>   
>>> +/*
>>> + * netdev_is_modern() returns true when the backend needs to bypass
>>> + * qemu_opts_parse_noisily()
>>> + */
>>> +static bool netdev_is_modern(const char *optarg)
>>> +{
>>> +    return false;
>>> +}
>>> +
>>>   int net_client_parse(QemuOptsList *opts_list, const char *optarg)
>>>   {
>>> +    if (netdev_is_modern(optarg)) {
>>> +            /*
>>> +             * We need to bypass qemu_opts_parse_noisily() to accept
>>> +             * new style object like addr.type=inet in SocketAddress
>>> +             */
>> 
>> I'm not sure this will makes sense to future readers.
>> 
>> What about "Use modern, more expressive syntax"?
>
> Done.
>
>> 
>>> +            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);
>>> +            nd->is_netdev = strcmp(opts_list->name, "netdev") == 0;
>>> +
>>> +            QSIMPLEQ_INSERT_TAIL(&nd_queue, nd, entry);
>>> +            return 0;
>>> +    }
>> 
>> Matches what we do for -blockdev, except we additionally have
>> nd->is_netdev.  We need it for calling net_client_init1().
>> 
>> If netdev_is_modern(optarg), then the only use of parameter @opts_list
>> is opts_list->name in the initialization of nd->is_netdev.
>> 
>> There's a bit of code smell, I'm afraid.
>
> I don't see what is the problem.

The function's signature

    int net_client_parse(QemuOptsList *opts_list, const char *optarg)

suggests we're parsing @optarg into @opts_list.

We do only if !netdev_is_modern(optarg).  In other words, the function's
actual behavior doesn't match reasonable expectations based on
signature.  A function comment would mitigate.

If nd->is_netdev wasn't needed, we could code all this just like
-blockdev.  I think that would be simpler.

>> I believe @is_netdev needs to be true for -netdev, -nic, and netdev_add;
>> false for -net.
>> 
>> Will we ever use the modern syntax with -net?
>
> Yes, I think we should support the same syntax with -netdev and -net.
>
> My first iteration was to pass is_netdev=true to net_client_init1() and Stefano reported a 
> problem with "-net" with things like that:
>
>      -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
>
>> 
>> Any chance we can deprecate -net?
>
> Who can decide of that?

Thomas, I think you've done some work to replace use cases of -net.  Do
you know what's left?

>>> +
>>>       if (!qemu_opts_parse_noisily(opts_list, optarg, true)) {
>>>           return -1;
>>>       }
>> 
>
> Thanks,
> Laurent

[RFC PATCH v2 3/8] qapi: net: add stream and dgram netdevs

[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 netdev, multicast is detected
according to the IP address type.
"listen" and "connect" modes are managed by stream netdev. An optional
parameter "server" defines the mode (server by default)

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 hmp-commands.hx |   2 +-
 net/clients.h   |   6 +
 net/dgram.c     | 630 ++++++++++++++++++++++++++++++++++++++++++++++++
 net/hub.c       |   2 +
 net/meson.build |   2 +
 net/net.c       |  24 +-
 net/stream.c    | 425 ++++++++++++++++++++++++++++++++
 qapi/net.json   |  38 ++-
 8 files changed, 1125 insertions(+), 4 deletions(-)
 create mode 100644 net/dgram.c
 create mode 100644 net/stream.c

diff --git a/hmp-commands.hx b/hmp-commands.hx
index 03e6a73d1f55..172dbab1dfed 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|stream|dgram|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..c1b51d79b147 100644
--- a/net/clients.h
+++ b/net/clients.h
@@ -40,6 +40,12 @@ 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_stream(const Netdev *netdev, const char *name,
+                    NetClientState *peer, Error **errp);
+
+int net_init_dgram(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/dgram.c b/net/dgram.c
new file mode 100644
index 000000000000..aa4240501ed0
--- /dev/null
+++ b/net/dgram.c
@@ -0,0 +1,630 @@
+/*
+ * 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 NetDgramState {
+    NetClientState nc;
+    int listen_fd;
+    int fd;
+    SocketReadState rs;
+  /* 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? */
+} NetDgramState;
+
+static void net_dgram_accept(void *opaque);
+static void net_dgram_writable(void *opaque);
+
+static void net_dgram_update_fd_handler(NetDgramState *s)
+{
+    qemu_set_fd_handler(s->fd,
+                        s->read_poll ? s->send_fn : NULL,
+                        s->write_poll ? net_dgram_writable : NULL,
+                        s);
+}
+
+static void net_dgram_read_poll(NetDgramState *s, bool enable)
+{
+    s->read_poll = enable;
+    net_dgram_update_fd_handler(s);
+}
+
+static void net_dgram_write_poll(NetDgramState *s, bool enable)
+{
+    s->write_poll = enable;
+    net_dgram_update_fd_handler(s);
+}
+
+static void net_dgram_writable(void *opaque)
+{
+    NetDgramState *s = opaque;
+
+    net_dgram_write_poll(s, false);
+
+    qemu_flush_queued_packets(&s->nc);
+}
+
+static ssize_t net_dgram_receive_dgram(NetClientState *nc,
+                                       const uint8_t *buf, size_t size)
+{
+    NetDgramState *s = DO_UPCAST(NetDgramState, 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_dgram_write_poll(s, true);
+        return 0;
+    }
+    return ret;
+}
+
+static void net_dgram_send_completed(NetClientState *nc, ssize_t len)
+{
+    NetDgramState *s = DO_UPCAST(NetDgramState, nc, nc);
+
+    if (!s->read_poll) {
+        net_dgram_read_poll(s, true);
+    }
+}
+
+static void net_dgram_rs_finalize(SocketReadState *rs)
+{
+    NetDgramState *s = container_of(rs, NetDgramState, rs);
+
+    if (qemu_send_packet_async(&s->nc, rs->buf,
+                               rs->packet_len,
+                               net_dgram_send_completed) == 0) {
+        net_dgram_read_poll(s, false);
+    }
+}
+
+static void net_dgram_send(void *opaque)
+{
+    NetDgramState *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_dgram_read_poll(s, false);
+        net_dgram_write_poll(s, false);
+        if (s->listen_fd != -1) {
+            qemu_set_fd_handler(s->listen_fd, net_dgram_accept, NULL, s);
+        }
+        closesocket(s->fd);
+
+        s->fd = -1;
+        net_socket_rs_init(&s->rs, net_dgram_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_dgram_send_dgram(void *opaque)
+{
+    NetDgramState *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_dgram_read_poll(s, false);
+        net_dgram_write_poll(s, false);
+        return;
+    }
+    if (qemu_send_packet_async(&s->nc, s->rs.buf, size,
+                               net_dgram_send_completed) == 0) {
+        net_dgram_read_poll(s, false);
+    }
+}
+
+static int net_dgram_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_dgram_cleanup(NetClientState *nc)
+{
+    NetDgramState *s = DO_UPCAST(NetDgramState, nc, nc);
+    if (s->fd != -1) {
+        net_dgram_read_poll(s, false);
+        net_dgram_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_DGRAM,
+    .size = sizeof(NetDgramState),
+    .receive = net_dgram_receive_dgram,
+    .cleanup = net_dgram_cleanup,
+};
+
+static NetDgramState *net_dgram_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;
+    NetDgramState *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_dgram_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(NetDgramState, nc, nc);
+
+    s->fd = fd;
+    s->listen_fd = -1;
+    s->send_fn = net_dgram_send_dgram;
+    net_socket_rs_init(&s->rs, net_dgram_rs_finalize, false);
+    net_dgram_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),
+                 "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), "fd=%d %s", fd,
+                 SocketAddressType_str(sa_type));
+    }
+
+    return s;
+
+err:
+    closesocket(fd);
+    return NULL;
+}
+
+static void net_dgram_connect(void *opaque)
+{
+    NetDgramState *s = opaque;
+    s->send_fn = net_dgram_send;
+    net_dgram_read_poll(s, true);
+}
+
+static void net_dgram_accept(void *opaque)
+{
+    NetDgramState *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_dgram_connect(s);
+    snprintf(s->nc.info_str, sizeof(s->nc.info_str), "connection from %s:%d",
+             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+}
+
+static int net_dgram_mcast_init(NetClientState *peer,
+                                const char *model,
+                                const char *name,
+                                SocketAddress *remote,
+                                SocketAddress *local,
+                                Error **errp)
+{
+    NetDgramState *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_dgram_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_dgram_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_dgram_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), "mcast=%s:%d",
+             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+    return 0;
+
+}
+
+static int net_dgram_udp_init(NetClientState *peer,
+                              const char *model,
+                              const char *name,
+                              SocketAddress *remote,
+                              SocketAddress *local,
+                              Error **errp)
+{
+    NetDgramState *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 requires 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("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_dgram_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_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_dgram_mcast_init(peer, model, name, remote, local,
+                                           errp);
+        }
+    }
+    /* unicast address */
+    if (!local) {
+        error_setg(errp, "dgram requires local= parameter");
+        return -1;
+    }
+    return net_dgram_udp_init(peer, model, name, remote, local, errp);
+}
+
+int net_init_dgram(const Netdev *netdev, const char *name,
+                   NetClientState *peer, Error **errp)
+{
+    const NetdevDgramOptions *sock;
+
+    assert(netdev->type == NET_CLIENT_DRIVER_DGRAM);
+    sock = &netdev->u.dgram;
+
+    return net_dgram_init(peer, "dgram", name, sock->remote, sock->local,
+                          errp);
+}
diff --git a/net/hub.c b/net/hub.c
index 1375738bf121..67ca53485638 100644
--- a/net/hub.c
+++ b/net/hub.c
@@ -313,6 +313,8 @@ 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_STREAM:
+            case NET_CLIENT_DRIVER_DGRAM:
             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..2c8358baadb3 100644
--- a/net/meson.build
+++ b/net/meson.build
@@ -13,6 +13,8 @@ softmmu_ss.add(files(
   'net.c',
   'queue.c',
   'socket.c',
+  'stream.c',
+  'dgram.c',
   'util.c',
 ))
 
diff --git a/net/net.c b/net/net.c
index 2aab7167316c..fd6b30a10c57 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1015,6 +1015,8 @@ 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_STREAM]    = net_init_stream,
+        [NET_CLIENT_DRIVER_DGRAM]     = net_init_dgram,
 #ifdef CONFIG_VDE
         [NET_CLIENT_DRIVER_VDE]       = net_init_vde,
 #endif
@@ -1097,6 +1099,8 @@ void show_netdevs(void)
     int idx;
     const char *available_netdevs[] = {
         "socket",
+        "stream",
+        "dgram",
         "hubport",
         "tap",
 #ifdef CONFIG_SLIRP
@@ -1606,7 +1610,25 @@ int net_init_clients(Error **errp)
  */
 static bool netdev_is_modern(const char *optarg)
 {
-    return false;
+    static QemuOptsList dummy_opts = {
+        .name = "netdev",
+        .implied_opt_name = "type",
+        .head = QTAILQ_HEAD_INITIALIZER(dummy_opts.head),
+        .desc = { { } },
+    };
+    const char *netdev;
+    QemuOpts *opts;
+    bool is_modern;
+
+    opts = qemu_opts_parse(&dummy_opts, optarg, true, &error_fatal);
+    netdev = qemu_opt_get(opts, "type");
+
+    is_modern = strcmp(netdev, "stream") == 0 ||
+                strcmp(netdev, "dgram") == 0;
+
+    qemu_opts_reset(&dummy_opts);
+
+    return is_modern;
 }
 
 int net_client_parse(QemuOptsList *opts_list, const char *optarg)
diff --git a/net/stream.c b/net/stream.c
new file mode 100644
index 000000000000..fdc97ee43a56
--- /dev/null
+++ b/net/stream.c
@@ -0,0 +1,425 @@
+/*
+ * 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 NetStreamState {
+    NetClientState nc;
+    int listen_fd;
+    int fd;
+    SocketReadState rs;
+    unsigned int send_index;      /* number of bytes sent*/
+    IOHandler *send_fn;
+    bool read_poll;               /* waiting to receive data? */
+    bool write_poll;              /* waiting to transmit data? */
+} NetStreamState;
+
+static void net_stream_accept(void *opaque);
+static void net_stream_writable(void *opaque);
+
+static void net_stream_update_fd_handler(NetStreamState *s)
+{
+    qemu_set_fd_handler(s->fd,
+                        s->read_poll ? s->send_fn : NULL,
+                        s->write_poll ? net_stream_writable : NULL,
+                        s);
+}
+
+static void net_stream_read_poll(NetStreamState *s, bool enable)
+{
+    s->read_poll = enable;
+    net_stream_update_fd_handler(s);
+}
+
+static void net_stream_write_poll(NetStreamState *s, bool enable)
+{
+    s->write_poll = enable;
+    net_stream_update_fd_handler(s);
+}
+
+static void net_stream_writable(void *opaque)
+{
+    NetStreamState *s = opaque;
+
+    net_stream_write_poll(s, false);
+
+    qemu_flush_queued_packets(&s->nc);
+}
+
+static ssize_t net_stream_receive(NetClientState *nc, const uint8_t *buf,
+                                  size_t size)
+{
+    NetStreamState *s = DO_UPCAST(NetStreamState, 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_stream_write_poll(s, true);
+        return 0;
+    }
+    s->send_index = 0;
+    return size;
+}
+
+static void net_stream_send_completed(NetClientState *nc, ssize_t len)
+{
+    NetStreamState *s = DO_UPCAST(NetStreamState, nc, nc);
+
+    if (!s->read_poll) {
+        net_stream_read_poll(s, true);
+    }
+}
+
+static void net_stream_rs_finalize(SocketReadState *rs)
+{
+    NetStreamState *s = container_of(rs, NetStreamState, rs);
+
+    if (qemu_send_packet_async(&s->nc, rs->buf,
+                               rs->packet_len,
+                               net_stream_send_completed) == 0) {
+        net_stream_read_poll(s, false);
+    }
+}
+
+static void net_stream_send(void *opaque)
+{
+    NetStreamState *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_stream_read_poll(s, false);
+        net_stream_write_poll(s, false);
+        if (s->listen_fd != -1) {
+            qemu_set_fd_handler(s->listen_fd, net_stream_accept, NULL, s);
+        }
+        closesocket(s->fd);
+
+        s->fd = -1;
+        net_socket_rs_init(&s->rs, net_stream_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_stream_cleanup(NetClientState *nc)
+{
+    NetStreamState *s = DO_UPCAST(NetStreamState, nc, nc);
+    if (s->fd != -1) {
+        net_stream_read_poll(s, false);
+        net_stream_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 void net_stream_connect(void *opaque)
+{
+    NetStreamState *s = opaque;
+    s->send_fn = net_stream_send;
+    net_stream_read_poll(s, true);
+}
+
+static NetClientInfo net_stream_info = {
+    .type = NET_CLIENT_DRIVER_STREAM,
+    .size = sizeof(NetStreamState),
+    .receive = net_stream_receive,
+    .cleanup = net_stream_cleanup,
+};
+
+static NetStreamState *net_stream_fd_init_stream(NetClientState *peer,
+                                                 const char *model,
+                                                 const char *name,
+                                                 int fd, int is_connected)
+{
+    NetClientState *nc;
+    NetStreamState *s;
+
+    nc = qemu_new_net_client(&net_stream_info, peer, model, name);
+
+    snprintf(nc->info_str, sizeof(nc->info_str), "fd=%d", fd);
+
+    s = DO_UPCAST(NetStreamState, nc, nc);
+
+    s->fd = fd;
+    s->listen_fd = -1;
+    net_socket_rs_init(&s->rs, net_stream_rs_finalize, false);
+
+    /* Disable Nagle algorithm on TCP sockets to reduce latency */
+    socket_set_nodelay(fd);
+
+    if (is_connected) {
+        net_stream_connect(s);
+    } else {
+        qemu_set_fd_handler(s->fd, NULL, net_stream_connect, s);
+    }
+    return s;
+}
+
+static void net_stream_accept(void *opaque)
+{
+    NetStreamState *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_stream_connect(s);
+    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
+             "connection from %s:%d",
+             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+}
+
+static int net_stream_server_init(NetClientState *peer,
+                                  const char *model,
+                                  const char *name,
+                                  SocketAddress *addr,
+                                  Error **errp)
+{
+    NetClientState *nc;
+    NetStreamState *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_stream_info, peer, model, name);
+    s = DO_UPCAST(NetStreamState, nc, nc);
+    s->fd = -1;
+    s->listen_fd = fd;
+    s->nc.link_down = true;
+    net_socket_rs_init(&s->rs, net_stream_rs_finalize, false);
+
+    qemu_set_fd_handler(s->listen_fd, net_stream_accept, NULL, s);
+    return 0;
+}
+
+static int net_stream_client_init(NetClientState *peer,
+                                  const char *model,
+                                  const char *name,
+                                  SocketAddress *addr,
+                                  Error **errp)
+{
+    NetStreamState *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("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("connect to fd %d", fd);
+        break;
+    default:
+        error_setg(errp, "only support inet or fd type");
+        return -1;
+    }
+
+    s = net_stream_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;
+}
+
+int net_init_stream(const Netdev *netdev, const char *name,
+                    NetClientState *peer, Error **errp)
+{
+    const NetdevStreamOptions *sock;
+
+    assert(netdev->type == NET_CLIENT_DRIVER_STREAM);
+    sock = &netdev->u.stream;
+
+    if (!sock->has_server || sock->server) {
+        return net_stream_server_init(peer, "stream", name, sock->addr, errp);
+    }
+    return net_stream_client_init(peer, "stream", name, sock->addr, errp);
+}
diff --git a/qapi/net.json b/qapi/net.json
index b92f3f5fb444..eef288886e1b 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -7,6 +7,7 @@
 ##
 
 { 'include': 'common.json' }
+{ 'include': 'sockets.json' }
 
 ##
 # @set_link:
@@ -452,6 +453,37 @@
     '*vhostdev':     'str',
     '*queues':       'int' } }
 
+##
+# @NetdevStreamOptions:
+#
+# Configuration info for stream socket netdev
+#
+# @addr: socket address to listen on (server=true)
+#        or connect to (server=false)
+# @server: create server socket (default: true)
+#
+# Since: 7.1
+##
+{ 'struct': 'NetdevStreamOptions',
+  'data': {
+    'addr':   'SocketAddress',
+    '*server': 'bool' } }
+
+##
+# @NetdevDgramOptions:
+#
+# Configuration info for datagram socket netdev.
+#
+# @remote: remote address
+# @local: local address
+#
+# Since: 7.1
+##
+{ 'struct': 'NetdevDgramOptions',
+  'data': {
+    '*local':  'SocketAddress',
+    '*remote': 'SocketAddress' } }
+
 ##
 # @NetClientDriver:
 #
@@ -462,8 +494,8 @@
 #        @vhost-vdpa since 5.1
 ##
 { 'enum': 'NetClientDriver',
-  'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'vde',
-            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
+  'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'stream', 'dgram',
+            'vde', 'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
 
 ##
 # @Netdev:
@@ -487,6 +519,8 @@
     'tap':      'NetdevTapOptions',
     'l2tpv3':   'NetdevL2TPv3Options',
     'socket':   'NetdevSocketOptions',
+    'stream':   'NetdevStreamOptions',
+    'dgram':    'NetdevDgramOptions',
     'vde':      'NetdevVdeOptions',
     'bridge':   'NetdevBridgeOptions',
     'hubport':  'NetdevHubPortOptions',
-- 
2.35.3

Re: [RFC PATCH v2 3/8] qapi: net: add stream and dgram netdevs

[Markus Armbruster]

Laurent Vivier <lvivier@redhat.com> writes:

> 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 netdev, multicast is detected
> according to the IP address type.
> "listen" and "connect" modes are managed by stream netdev. An optional
> parameter "server" defines the mode (server by default)
>
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  hmp-commands.hx |   2 +-
>  net/clients.h   |   6 +
>  net/dgram.c     | 630 ++++++++++++++++++++++++++++++++++++++++++++++++
>  net/hub.c       |   2 +
>  net/meson.build |   2 +
>  net/net.c       |  24 +-
>  net/stream.c    | 425 ++++++++++++++++++++++++++++++++
>  qapi/net.json   |  38 ++-
>  8 files changed, 1125 insertions(+), 4 deletions(-)
>  create mode 100644 net/dgram.c
>  create mode 100644 net/stream.c
>
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 03e6a73d1f55..172dbab1dfed 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|stream|dgram|vde|bridge|hubport|netmap|vhost-user],id=str[,prop=value][,...]",
>          .help       = "add host network device",
>          .cmd        = hmp_netdev_add,
>          .command_completion = netdev_add_completion,

Does qemu-options.hx need an update, too?

> diff --git a/net/clients.h b/net/clients.h
> index 92f9b59aedce..c1b51d79b147 100644
> --- a/net/clients.h
> +++ b/net/clients.h
> @@ -40,6 +40,12 @@ 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_stream(const Netdev *netdev, const char *name,
> +                    NetClientState *peer, Error **errp);
> +
> +int net_init_dgram(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/dgram.c b/net/dgram.c
> new file mode 100644
> index 000000000000..aa4240501ed0
> --- /dev/null
> +++ b/net/dgram.c
> @@ -0,0 +1,630 @@
> +/*
> + * 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.
> + */

Blank line here, please.

Why not GPLv2+?

> +#include "qemu/osdep.h"

[...]

> diff --git a/net/net.c b/net/net.c
> index 2aab7167316c..fd6b30a10c57 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -1015,6 +1015,8 @@ 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_STREAM]    = net_init_stream,
> +        [NET_CLIENT_DRIVER_DGRAM]     = net_init_dgram,
>  #ifdef CONFIG_VDE
>          [NET_CLIENT_DRIVER_VDE]       = net_init_vde,
>  #endif
> @@ -1097,6 +1099,8 @@ void show_netdevs(void)
>      int idx;
>      const char *available_netdevs[] = {
>          "socket",
> +        "stream",
> +        "dgram",
>          "hubport",
>          "tap",
>  #ifdef CONFIG_SLIRP
> @@ -1606,7 +1610,25 @@ int net_init_clients(Error **errp)
>   */
>  static bool netdev_is_modern(const char *optarg)
>  {
> -    return false;
> +    static QemuOptsList dummy_opts = {
> +        .name = "netdev",
> +        .implied_opt_name = "type",
> +        .head = QTAILQ_HEAD_INITIALIZER(dummy_opts.head),
> +        .desc = { { } },
> +    };
> +    const char *netdev;
> +    QemuOpts *opts;
> +    bool is_modern;
> +
> +    opts = qemu_opts_parse(&dummy_opts, optarg, true, &error_fatal);
> +    netdev = qemu_opt_get(opts, "type");
> +
> +    is_modern = strcmp(netdev, "stream") == 0 ||
> +                strcmp(netdev, "dgram") == 0;

Crashes when user neglects to pass "type".
> +
> +    qemu_opts_reset(&dummy_opts);
> +
> +    return is_modern;
>  }

Reminder: netdev_is_modern() governs whether to use QemuOpts + opts
visitor or qobject_input_visitor_new_str().

To decide, it uses QemuOpts with a dummy QemuOptsList.

Since we parse errors are fatal here, new syntax must also parse fine as
QemuOpts.  Undesirable, I think.

Cleaner, I think:

    args = keyval_parse(optarg, "type", NULL, NULL);
    if (!args) {
        return false;
    }
    type = qdict_get_try_str(args, "type");
    return !g_strcmp0(type, "dgram") || !g_strcmp0(type, "stream");

Not even compile-tested.

Still probematic: syntax error reporting.  When keyval_parse() fails
here, we use QemuOpts, and therefore get QemuOpts syntax errors.  I fear
that could be quite confusing.

>  
>  int net_client_parse(QemuOptsList *opts_list, const char *optarg)
> diff --git a/net/stream.c b/net/stream.c
> new file mode 100644
> index 000000000000..fdc97ee43a56
> --- /dev/null
> +++ b/net/stream.c
> @@ -0,0 +1,425 @@
> +/*
> + * 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.
> + */

Blank line here, please.

Why not GPLv2+?

> +#include "qemu/osdep.h"

[...]

> diff --git a/qapi/net.json b/qapi/net.json
> index b92f3f5fb444..eef288886e1b 100644
> --- a/qapi/net.json
> +++ b/qapi/net.json
> @@ -7,6 +7,7 @@
>  ##
>  
>  { 'include': 'common.json' }
> +{ 'include': 'sockets.json' }
>  
>  ##
>  # @set_link:
> @@ -452,6 +453,37 @@
>      '*vhostdev':     'str',
>      '*queues':       'int' } }
>  
> +##
> +# @NetdevStreamOptions:
> +#
> +# Configuration info for stream socket netdev
> +#
> +# @addr: socket address to listen on (server=true)
> +#        or connect to (server=false)
> +# @server: create server socket (default: true)
> +#
> +# Since: 7.1
> +##
> +{ 'struct': 'NetdevStreamOptions',
> +  'data': {
> +    'addr':   'SocketAddress',
> +    '*server': 'bool' } }
> +
> +##
> +# @NetdevDgramOptions:
> +#
> +# Configuration info for datagram socket netdev.
> +#
> +# @remote: remote address
> +# @local: local address

Defaults?

> +#
> +# Since: 7.1
> +##
> +{ 'struct': 'NetdevDgramOptions',
> +  'data': {
> +    '*local':  'SocketAddress',
> +    '*remote': 'SocketAddress' } }
> +
>  ##
>  # @NetClientDriver:
>  #
> @@ -462,8 +494,8 @@
>  #        @vhost-vdpa since 5.1
>  ##
>  { 'enum': 'NetClientDriver',
> -  'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'vde',
> -            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
> +  'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'stream', 'dgram',
> +            'vde', 'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }

Long lines.
>  
>  ##
>  # @Netdev:
> @@ -487,6 +519,8 @@
>      'tap':      'NetdevTapOptions',
>      'l2tpv3':   'NetdevL2TPv3Options',
>      'socket':   'NetdevSocketOptions',
> +    'stream':   'NetdevStreamOptions',
> +    'dgram':    'NetdevDgramOptions',
>      'vde':      'NetdevVdeOptions',
>      'bridge':   'NetdevBridgeOptions',
>      'hubport':  'NetdevHubPortOptions',

Re: [RFC PATCH v2 3/8] qapi: net: add stream and dgram netdevs

[Laurent Vivier]

On 13/05/2022 13:44, Markus Armbruster wrote:
> Laurent Vivier <lvivier@redhat.com> writes:
> 
>> 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 netdev, multicast is detected
>> according to the IP address type.
>> "listen" and "connect" modes are managed by stream netdev. An optional
>> parameter "server" defines the mode (server by default)
>>
>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>> ---
>>   hmp-commands.hx |   2 +-
>>   net/clients.h   |   6 +
>>   net/dgram.c     | 630 ++++++++++++++++++++++++++++++++++++++++++++++++
>>   net/hub.c       |   2 +
>>   net/meson.build |   2 +
>>   net/net.c       |  24 +-
>>   net/stream.c    | 425 ++++++++++++++++++++++++++++++++
>>   qapi/net.json   |  38 ++-
>>   8 files changed, 1125 insertions(+), 4 deletions(-)
>>   create mode 100644 net/dgram.c
>>   create mode 100644 net/stream.c
>>
>> diff --git a/hmp-commands.hx b/hmp-commands.hx
>> index 03e6a73d1f55..172dbab1dfed 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|stream|dgram|vde|bridge|hubport|netmap|vhost-user],id=str[,prop=value][,...]",
>>           .help       = "add host network device",
>>           .cmd        = hmp_netdev_add,
>>           .command_completion = netdev_add_completion,
> 
> Does qemu-options.hx need an update, too?

Done

> 
>> diff --git a/net/clients.h b/net/clients.h
>> index 92f9b59aedce..c1b51d79b147 100644
>> --- a/net/clients.h
>> +++ b/net/clients.h
>> @@ -40,6 +40,12 @@ 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_stream(const Netdev *netdev, const char *name,
>> +                    NetClientState *peer, Error **errp);
>> +
>> +int net_init_dgram(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/dgram.c b/net/dgram.c
>> new file mode 100644
>> index 000000000000..aa4240501ed0
>> --- /dev/null
>> +++ b/net/dgram.c
>> @@ -0,0 +1,630 @@
>> +/*
>> + * 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.
>> + */
> 
> Blank line here, please.
> 
> Why not GPLv2+?

I've kept the original text copied from net/socket.c, but I can move this to GPL2+

> 
>> +#include "qemu/osdep.h"
> 
> [...]
> 
>> diff --git a/net/net.c b/net/net.c
>> index 2aab7167316c..fd6b30a10c57 100644
>> --- a/net/net.c
>> +++ b/net/net.c
>> @@ -1015,6 +1015,8 @@ 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_STREAM]    = net_init_stream,
>> +        [NET_CLIENT_DRIVER_DGRAM]     = net_init_dgram,
>>   #ifdef CONFIG_VDE
>>           [NET_CLIENT_DRIVER_VDE]       = net_init_vde,
>>   #endif
>> @@ -1097,6 +1099,8 @@ void show_netdevs(void)
>>       int idx;
>>       const char *available_netdevs[] = {
>>           "socket",
>> +        "stream",
>> +        "dgram",
>>           "hubport",
>>           "tap",
>>   #ifdef CONFIG_SLIRP
>> @@ -1606,7 +1610,25 @@ int net_init_clients(Error **errp)
>>    */
>>   static bool netdev_is_modern(const char *optarg)
>>   {
>> -    return false;
>> +    static QemuOptsList dummy_opts = {
>> +        .name = "netdev",
>> +        .implied_opt_name = "type",
>> +        .head = QTAILQ_HEAD_INITIALIZER(dummy_opts.head),
>> +        .desc = { { } },
>> +    };
>> +    const char *netdev;
>> +    QemuOpts *opts;
>> +    bool is_modern;
>> +
>> +    opts = qemu_opts_parse(&dummy_opts, optarg, true, &error_fatal);
>> +    netdev = qemu_opt_get(opts, "type");
>> +
>> +    is_modern = strcmp(netdev, "stream") == 0 ||
>> +                strcmp(netdev, "dgram") == 0;
> 
> Crashes when user neglects to pass "type".

I think "type" is always passed because of the '.implied_opt_name = "type"'. Am I wrong?


>> +
>> +    qemu_opts_reset(&dummy_opts);
>> +
>> +    return is_modern;
>>   }
> 
> Reminder: netdev_is_modern() governs whether to use QemuOpts + opts
> visitor or qobject_input_visitor_new_str().
> 
> To decide, it uses QemuOpts with a dummy QemuOptsList.
> 
> Since we parse errors are fatal here, new syntax must also parse fine as
> QemuOpts.  Undesirable, I think.
> 
> Cleaner, I think:
> 
>      args = keyval_parse(optarg, "type", NULL, NULL);
>      if (!args) {
>          return false;
>      }
>      type = qdict_get_try_str(args, "type");
>      return !g_strcmp0(type, "dgram") || !g_strcmp0(type, "stream");
> 
> Not even compile-tested.

ok, I try that.

> Still probematic: syntax error reporting.  When keyval_parse() fails
> here, we use QemuOpts, and therefore get QemuOpts syntax errors.  I fear
> that could be quite confusing.
> 
>>   
>>   int net_client_parse(QemuOptsList *opts_list, const char *optarg)
>> diff --git a/net/stream.c b/net/stream.c
>> new file mode 100644
>> index 000000000000..fdc97ee43a56
>> --- /dev/null
>> +++ b/net/stream.c
>> @@ -0,0 +1,425 @@
>> +/*
>> + * 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.
>> + */
> 
> Blank line here, please.
> 
> Why not GPLv2+?

As above.

> 
>> +#include "qemu/osdep.h"
> 
> [...]
> 
>> diff --git a/qapi/net.json b/qapi/net.json
>> index b92f3f5fb444..eef288886e1b 100644
>> --- a/qapi/net.json
>> +++ b/qapi/net.json
>> @@ -7,6 +7,7 @@
>>   ##
>>   
>>   { 'include': 'common.json' }
>> +{ 'include': 'sockets.json' }
>>   
>>   ##
>>   # @set_link:
>> @@ -452,6 +453,37 @@
>>       '*vhostdev':     'str',
>>       '*queues':       'int' } }
>>   
>> +##
>> +# @NetdevStreamOptions:
>> +#
>> +# Configuration info for stream socket netdev
>> +#
>> +# @addr: socket address to listen on (server=true)
>> +#        or connect to (server=false)
>> +# @server: create server socket (default: true)
>> +#
>> +# Since: 7.1
>> +##
>> +{ 'struct': 'NetdevStreamOptions',
>> +  'data': {
>> +    'addr':   'SocketAddress',
>> +    '*server': 'bool' } }
>> +
>> +##
>> +# @NetdevDgramOptions:
>> +#
>> +# Configuration info for datagram socket netdev.
>> +#
>> +# @remote: remote address
>> +# @local: local address
> 
> Defaults?

We can't have a default because for multicast default is remoTe, and for unicast default 
is local.

> 
>> +#
>> +# Since: 7.1
>> +##
>> +{ 'struct': 'NetdevDgramOptions',
>> +  'data': {
>> +    '*local':  'SocketAddress',
>> +    '*remote': 'SocketAddress' } }
>> +
>>   ##
>>   # @NetClientDriver:
>>   #
>> @@ -462,8 +494,8 @@
>>   #        @vhost-vdpa since 5.1
>>   ##
>>   { 'enum': 'NetClientDriver',
>> -  'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'vde',
>> -            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
>> +  'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'stream', 'dgram',
>> +            'vde', 'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
> 
> Long lines.

ok

>>   
>>   ##
>>   # @Netdev:
>> @@ -487,6 +519,8 @@
>>       'tap':      'NetdevTapOptions',
>>       'l2tpv3':   'NetdevL2TPv3Options',
>>       'socket':   'NetdevSocketOptions',
>> +    'stream':   'NetdevStreamOptions',
>> +    'dgram':    'NetdevDgramOptions',
>>       'vde':      'NetdevVdeOptions',
>>       'bridge':   'NetdevBridgeOptions',
>>       'hubport':  'NetdevHubPortOptions',
> 

Thanks,
Laurent

Re: [RFC PATCH v2 3/8] qapi: net: add stream and dgram netdevs

[Markus Armbruster]

Laurent Vivier <lvivier@redhat.com> writes:

> On 13/05/2022 13:44, Markus Armbruster wrote:
>> Laurent Vivier <lvivier@redhat.com> writes:
>> 
>>> 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 netdev, multicast is detected
>>> according to the IP address type.
>>> "listen" and "connect" modes are managed by stream netdev. An optional
>>> parameter "server" defines the mode (server by default)
>>>
>>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>>> ---
>>>   hmp-commands.hx |   2 +-
>>>   net/clients.h   |   6 +
>>>   net/dgram.c     | 630 ++++++++++++++++++++++++++++++++++++++++++++++++
>>>   net/hub.c       |   2 +
>>>   net/meson.build |   2 +
>>>   net/net.c       |  24 +-
>>>   net/stream.c    | 425 ++++++++++++++++++++++++++++++++
>>>   qapi/net.json   |  38 ++-
>>>   8 files changed, 1125 insertions(+), 4 deletions(-)
>>>   create mode 100644 net/dgram.c
>>>   create mode 100644 net/stream.c
>>>
>>> diff --git a/hmp-commands.hx b/hmp-commands.hx
>>> index 03e6a73d1f55..172dbab1dfed 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|stream|dgram|vde|bridge|hubport|netmap|vhost-user],id=str[,prop=value][,...]",
>>>           .help       = "add host network device",
>>>           .cmd        = hmp_netdev_add,
>>>           .command_completion = netdev_add_completion,
>> 
>> Does qemu-options.hx need an update, too?
>
> Done
>
>> 
>>> diff --git a/net/clients.h b/net/clients.h
>>> index 92f9b59aedce..c1b51d79b147 100644
>>> --- a/net/clients.h
>>> +++ b/net/clients.h
>>> @@ -40,6 +40,12 @@ 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_stream(const Netdev *netdev, const char *name,
>>> +                    NetClientState *peer, Error **errp);
>>> +
>>> +int net_init_dgram(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/dgram.c b/net/dgram.c
>>> new file mode 100644
>>> index 000000000000..aa4240501ed0
>>> --- /dev/null
>>> +++ b/net/dgram.c
>>> @@ -0,0 +1,630 @@
>>> +/*
>>> + * 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.
>>> + */
>> 
>> Blank line here, please.
>> 
>> Why not GPLv2+?
>
> I've kept the original text copied from net/socket.c, but I can move this to GPL2+

If the file's contents is derived from net/socket.c, copying the
legalese from there makes sense.

>>> +#include "qemu/osdep.h"
>> 
>> [...]
>> 
>>> diff --git a/net/net.c b/net/net.c
>>> index 2aab7167316c..fd6b30a10c57 100644
>>> --- a/net/net.c
>>> +++ b/net/net.c
>>> @@ -1015,6 +1015,8 @@ 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_STREAM]    = net_init_stream,
>>> +        [NET_CLIENT_DRIVER_DGRAM]     = net_init_dgram,
>>>   #ifdef CONFIG_VDE
>>>           [NET_CLIENT_DRIVER_VDE]       = net_init_vde,
>>>   #endif
>>> @@ -1097,6 +1099,8 @@ void show_netdevs(void)
>>>       int idx;
>>>       const char *available_netdevs[] = {
>>>           "socket",
>>> +        "stream",
>>> +        "dgram",
>>>           "hubport",
>>>           "tap",
>>>   #ifdef CONFIG_SLIRP
>>> @@ -1606,7 +1610,25 @@ int net_init_clients(Error **errp)
>>>    */
>>>   static bool netdev_is_modern(const char *optarg)
>>>   {
>>> -    return false;
>>> +    static QemuOptsList dummy_opts = {
>>> +        .name = "netdev",
>>> +        .implied_opt_name = "type",
>>> +        .head = QTAILQ_HEAD_INITIALIZER(dummy_opts.head),
>>> +        .desc = { { } },
>>> +    };
>>> +    const char *netdev;
>>> +    QemuOpts *opts;
>>> +    bool is_modern;
>>> +
>>> +    opts = qemu_opts_parse(&dummy_opts, optarg, true, &error_fatal);
>>> +    netdev = qemu_opt_get(opts, "type");
>>> +
>>> +    is_modern = strcmp(netdev, "stream") == 0 ||
>>> +                strcmp(netdev, "dgram") == 0;
>> 
>> Crashes when user neglects to pass "type".
>
> I think "type" is always passed because of the '.implied_opt_name = "type"'. Am I wrong?

.implied_opt_name = "type" lets you shorten "type=T,..." to "T,...".  It
doesn't make key "type" mandatory.  "-netdev id=foo" is still permitted.
Even "-netdev ''" is.

>>> +
>>> +    qemu_opts_reset(&dummy_opts);
>>> +
>>> +    return is_modern;
>>>   }
>> 
>> Reminder: netdev_is_modern() governs whether to use QemuOpts + opts
>> visitor or qobject_input_visitor_new_str().
>> 
>> To decide, it uses QemuOpts with a dummy QemuOptsList.
>> 
>> Since we parse errors are fatal here, new syntax must also parse fine as
>> QemuOpts.  Undesirable, I think.
>> 
>> Cleaner, I think:
>> 
>>      args = keyval_parse(optarg, "type", NULL, NULL);
>>      if (!args) {
>>          return false;
>>      }
>>      type = qdict_get_try_str(args, "type");
>>      return !g_strcmp0(type, "dgram") || !g_strcmp0(type, "stream");
>> 
>> Not even compile-tested.
>
> ok, I try that.
>
>> Still probematic: syntax error reporting.  When keyval_parse() fails
>> here, we use QemuOpts, and therefore get QemuOpts syntax errors.  I fear
>> that could be quite confusing.
>> 
>>>   
>>>   int net_client_parse(QemuOptsList *opts_list, const char *optarg)
>>> diff --git a/net/stream.c b/net/stream.c
>>> new file mode 100644
>>> index 000000000000..fdc97ee43a56
>>> --- /dev/null
>>> +++ b/net/stream.c
>>> @@ -0,0 +1,425 @@
>>> +/*
>>> + * 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.
>>> + */
>> 
>> Blank line here, please.
>> 
>> Why not GPLv2+?
>
> As above.
>
>> 
>>> +#include "qemu/osdep.h"
>> 
>> [...]
>> 
>>> diff --git a/qapi/net.json b/qapi/net.json
>>> index b92f3f5fb444..eef288886e1b 100644
>>> --- a/qapi/net.json
>>> +++ b/qapi/net.json
>>> @@ -7,6 +7,7 @@
>>>   ##
>>>   
>>>   { 'include': 'common.json' }
>>> +{ 'include': 'sockets.json' }
>>>   
>>>   ##
>>>   # @set_link:
>>> @@ -452,6 +453,37 @@
>>>       '*vhostdev':     'str',
>>>       '*queues':       'int' } }
>>>   
>>> +##
>>> +# @NetdevStreamOptions:
>>> +#
>>> +# Configuration info for stream socket netdev
>>> +#
>>> +# @addr: socket address to listen on (server=true)
>>> +#        or connect to (server=false)
>>> +# @server: create server socket (default: true)
>>> +#
>>> +# Since: 7.1
>>> +##
>>> +{ 'struct': 'NetdevStreamOptions',
>>> +  'data': {
>>> +    'addr':   'SocketAddress',
>>> +    '*server': 'bool' } }
>>> +
>>> +##
>>> +# @NetdevDgramOptions:
>>> +#
>>> +# Configuration info for datagram socket netdev.
>>> +#
>>> +# @remote: remote address
>>> +# @local: local address
>> 
>> Defaults?
>
> We can't have a default because for multicast default is remoTe, and for unicast default 
> is local.

Well, the members are optional, so there must be some default behavior,
which may or may not correspond to a single default value.  Regardless,
what happens when a member is absent ought to be documented.
>> 
>>> +#
>>> +# Since: 7.1
>>> +##
>>> +{ 'struct': 'NetdevDgramOptions',
>>> +  'data': {
>>> +    '*local':  'SocketAddress',
>>> +    '*remote': 'SocketAddress' } }
>>> +
>>>   ##
>>>   # @NetClientDriver:
>>>   #
>>> @@ -462,8 +494,8 @@
>>>   #        @vhost-vdpa since 5.1
>>>   ##
>>>   { 'enum': 'NetClientDriver',
>>> -  'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'vde',
>>> -            'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
>>> +  'data': [ 'none', 'nic', 'user', 'tap', 'l2tpv3', 'socket', 'stream', 'dgram',
>>> +            'vde', 'bridge', 'hubport', 'netmap', 'vhost-user', 'vhost-vdpa' ] }
>> 
>> Long lines.
>
> ok
>
>>>   
>>>   ##
>>>   # @Netdev:
>>> @@ -487,6 +519,8 @@
>>>       'tap':      'NetdevTapOptions',
>>>       'l2tpv3':   'NetdevL2TPv3Options',
>>>       'socket':   'NetdevSocketOptions',
>>> +    'stream':   'NetdevStreamOptions',
>>> +    'dgram':    'NetdevDgramOptions',
>>>       'vde':      'NetdevVdeOptions',
>>>       'bridge':   'NetdevBridgeOptions',
>>>       'hubport':  'NetdevHubPortOptions',
>> 
>
> Thanks,
> Laurent

You're welcome!

Re: [RFC PATCH v2 3/8] qapi: net: add stream and dgram netdevs

[Laurent Vivier]

On 15/06/2022 13:46, Markus Armbruster wrote:
> Laurent Vivier <lvivier@redhat.com> writes:
> 
>> On 13/05/2022 13:44, Markus Armbruster wrote:
>>> Laurent Vivier <lvivier@redhat.com> writes:
>>>
>>>> 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 netdev, multicast is detected
>>>> according to the IP address type.
>>>> "listen" and "connect" modes are managed by stream netdev. An optional
>>>> parameter "server" defines the mode (server by default)
>>>>
>>>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>>>> ---
>>>>    hmp-commands.hx |   2 +-
>>>>    net/clients.h   |   6 +
>>>>    net/dgram.c     | 630 ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>    net/hub.c       |   2 +
>>>>    net/meson.build |   2 +
>>>>    net/net.c       |  24 +-
>>>>    net/stream.c    | 425 ++++++++++++++++++++++++++++++++
>>>>    qapi/net.json   |  38 ++-
>>>>    8 files changed, 1125 insertions(+), 4 deletions(-)
>>>>    create mode 100644 net/dgram.c
>>>>    create mode 100644 net/stream.c
>>>>
...
>>>> diff --git a/net/net.c b/net/net.c
>>>> index 2aab7167316c..fd6b30a10c57 100644
>>>> --- a/net/net.c
>>>> +++ b/net/net.c
>>>> @@ -1015,6 +1015,8 @@ 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_STREAM]    = net_init_stream,
>>>> +        [NET_CLIENT_DRIVER_DGRAM]     = net_init_dgram,
>>>>    #ifdef CONFIG_VDE
>>>>            [NET_CLIENT_DRIVER_VDE]       = net_init_vde,
>>>>    #endif
>>>> @@ -1097,6 +1099,8 @@ void show_netdevs(void)
>>>>        int idx;
>>>>        const char *available_netdevs[] = {
>>>>            "socket",
>>>> +        "stream",
>>>> +        "dgram",
>>>>            "hubport",
>>>>            "tap",
>>>>    #ifdef CONFIG_SLIRP
>>>> @@ -1606,7 +1610,25 @@ int net_init_clients(Error **errp)
>>>>     */
>>>>    static bool netdev_is_modern(const char *optarg)
>>>>    {
>>>> -    return false;
>>>> +    static QemuOptsList dummy_opts = {
>>>> +        .name = "netdev",
>>>> +        .implied_opt_name = "type",
>>>> +        .head = QTAILQ_HEAD_INITIALIZER(dummy_opts.head),
>>>> +        .desc = { { } },
>>>> +    };
>>>> +    const char *netdev;
>>>> +    QemuOpts *opts;
>>>> +    bool is_modern;
>>>> +
>>>> +    opts = qemu_opts_parse(&dummy_opts, optarg, true, &error_fatal);
>>>> +    netdev = qemu_opt_get(opts, "type");
>>>> +
>>>> +    is_modern = strcmp(netdev, "stream") == 0 ||
>>>> +                strcmp(netdev, "dgram") == 0;
>>>
>>> Crashes when user neglects to pass "type".
>>
>> I think "type" is always passed because of the '.implied_opt_name = "type"'. Am I wrong?
> 
> .implied_opt_name = "type" lets you shorten "type=T,..." to "T,...".  It
> doesn't make key "type" mandatory.  "-netdev id=foo" is still permitted.
> Even "-netdev ''" is.


In fact type is checked before by QAPI definition:

{ 'union': 'Netdev',
   'base': { 'id': 'str', 'type': 'NetClientDriver' },
   'discriminator': 'type',
...

As it's the discriminator it must be there.

   $ qemu-system-x86_64 -netdev id=foo
   qemu-system-x86_64: -netdev id=foo: Parameter 'type' is missing

...
>>>> diff --git a/qapi/net.json b/qapi/net.json
>>>> index b92f3f5fb444..eef288886e1b 100644
>>>> --- a/qapi/net.json
>>>> +++ b/qapi/net.json
>>>> @@ -7,6 +7,7 @@
>>>>    ##
>>>>    
>>>>    { 'include': 'common.json' }
>>>> +{ 'include': 'sockets.json' }
>>>>    
>>>>    ##
>>>>    # @set_link:
>>>> @@ -452,6 +453,37 @@
>>>>        '*vhostdev':     'str',
>>>>        '*queues':       'int' } }
>>>>    
>>>> +##
>>>> +# @NetdevStreamOptions:
>>>> +#
>>>> +# Configuration info for stream socket netdev
>>>> +#
>>>> +# @addr: socket address to listen on (server=true)
>>>> +#        or connect to (server=false)
>>>> +# @server: create server socket (default: true)
>>>> +#
>>>> +# Since: 7.1
>>>> +##
>>>> +{ 'struct': 'NetdevStreamOptions',
>>>> +  'data': {
>>>> +    'addr':   'SocketAddress',
>>>> +    '*server': 'bool' } }
>>>> +
>>>> +##
>>>> +# @NetdevDgramOptions:
>>>> +#
>>>> +# Configuration info for datagram socket netdev.
>>>> +#
>>>> +# @remote: remote address
>>>> +# @local: local address
>>>
>>> Defaults?
>>
>> We can't have a default because for multicast default is remoTe, and for unicast default
>> is local.
> 
> Well, the members are optional, so there must be some default behavior,
> which may or may not correspond to a single default value.  Regardless,
> what happens when a member is absent ought to be documented.

The code checks there is at least one of these options and reports an error if not.

if remote address is present and it's a multicast address, local address is optional.

otherwise local address is required and remote address is optional.
I've updated qemu-options.hx with that syntax.

Thanks,
Laurent

Re: [RFC PATCH v2 3/8] qapi: net: add stream and dgram netdevs

[Markus Armbruster]

Laurent Vivier <lvivier@redhat.com> writes:

> On 15/06/2022 13:46, Markus Armbruster wrote:
>> Laurent Vivier <lvivier@redhat.com> writes:
>> 
>>> On 13/05/2022 13:44, Markus Armbruster wrote:
>>>> Laurent Vivier <lvivier@redhat.com> writes:
>>>>
>>>>> 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 netdev, multicast is detected
>>>>> according to the IP address type.
>>>>> "listen" and "connect" modes are managed by stream netdev. An optional
>>>>> parameter "server" defines the mode (server by default)
>>>>>
>>>>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>>>>> ---
>>>>>    hmp-commands.hx |   2 +-
>>>>>    net/clients.h   |   6 +
>>>>>    net/dgram.c     | 630 ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>    net/hub.c       |   2 +
>>>>>    net/meson.build |   2 +
>>>>>    net/net.c       |  24 +-
>>>>>    net/stream.c    | 425 ++++++++++++++++++++++++++++++++
>>>>>    qapi/net.json   |  38 ++-
>>>>>    8 files changed, 1125 insertions(+), 4 deletions(-)
>>>>>    create mode 100644 net/dgram.c
>>>>>    create mode 100644 net/stream.c
>>>>>
> ...
>>>>> diff --git a/net/net.c b/net/net.c
>>>>> index 2aab7167316c..fd6b30a10c57 100644
>>>>> --- a/net/net.c
>>>>> +++ b/net/net.c
>>>>> @@ -1015,6 +1015,8 @@ 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_STREAM]    = net_init_stream,
>>>>> +        [NET_CLIENT_DRIVER_DGRAM]     = net_init_dgram,
>>>>>    #ifdef CONFIG_VDE
>>>>>            [NET_CLIENT_DRIVER_VDE]       = net_init_vde,
>>>>>    #endif
>>>>> @@ -1097,6 +1099,8 @@ void show_netdevs(void)
>>>>>        int idx;
>>>>>        const char *available_netdevs[] = {
>>>>>            "socket",
>>>>> +        "stream",
>>>>> +        "dgram",
>>>>>            "hubport",
>>>>>            "tap",
>>>>>    #ifdef CONFIG_SLIRP
>>>>> @@ -1606,7 +1610,25 @@ int net_init_clients(Error **errp)
>>>>>     */
>>>>>    static bool netdev_is_modern(const char *optarg)
>>>>>    {
>>>>> -    return false;
>>>>> +    static QemuOptsList dummy_opts = {
>>>>> +        .name = "netdev",
>>>>> +        .implied_opt_name = "type",
>>>>> +        .head = QTAILQ_HEAD_INITIALIZER(dummy_opts.head),
>>>>> +        .desc = { { } },
>>>>> +    };
>>>>> +    const char *netdev;
>>>>> +    QemuOpts *opts;
>>>>> +    bool is_modern;
>>>>> +
>>>>> +    opts = qemu_opts_parse(&dummy_opts, optarg, true, &error_fatal);
>>>>> +    netdev = qemu_opt_get(opts, "type");
>>>>> +
>>>>> +    is_modern = strcmp(netdev, "stream") == 0 ||
>>>>> +                strcmp(netdev, "dgram") == 0;
>>>>
>>>> Crashes when user neglects to pass "type".
>>>
>>> I think "type" is always passed because of the '.implied_opt_name = "type"'. Am I wrong?
>> 
>> .implied_opt_name = "type" lets you shorten "type=T,..." to "T,...".  It
>> doesn't make key "type" mandatory.  "-netdev id=foo" is still permitted.
>> Even "-netdev ''" is.
>
>
> In fact type is checked before by QAPI definition:
>
> { 'union': 'Netdev',
>    'base': { 'id': 'str', 'type': 'NetClientDriver' },
>    'discriminator': 'type',
> ...
>
> As it's the discriminator it must be there.
>
>    $ qemu-system-x86_64 -netdev id=foo
>    qemu-system-x86_64: -netdev id=foo: Parameter 'type' is missing

It does crash for me:

    (gdb) bt
    #0  0x00007ffff4d25dcb in __strcmp_avx2 () at /lib64/libc.so.6
    #1  0x0000555555b4574b in netdev_is_modern (optarg=0x7fffffffe2ae "id=foo")
        at ../net/net.c:1626
    #2  0x0000555555b457ad in net_client_parse
        (opts_list=0x555556563780 <qemu_netdev_opts>, optarg=0x7fffffffe2ae "id=foo") at ../net/net.c:1636
    #3  0x0000555555ad98de in qemu_init (argc=3, argv=0x7fffffffdf08, envp=0x0)
        at ../softmmu/vl.c:2901
    #4  0x0000555555842c01 in qemu_main (argc=3, argv=0x7fffffffdf08, envp=0x0)
        at ../softmmu/main.c:35
    #5  0x0000555555842c37 in main (argc=3, argv=0x7fffffffdf08)
        at ../softmmu/main.c:45
    (gdb) up
    #1  0x0000555555b4574b in netdev_is_modern (optarg=0x7fffffffe2ae "id=foo")
        at ../net/net.c:1626
    1626	    is_modern = strcmp(netdev, "stream") == 0 ||
    (gdb) p netdev
    $1 = 0x0

This is

     https://github.com/patchew-project/qemu tags/patchew/20220512080932.735962-1-lvivier@redhat.com 

I suspect you tested with your v3, which doesn't crash for me, either.

[...]

Re: [RFC PATCH v2 3/8] qapi: net: add stream and dgram netdevs

[Laurent Vivier]

On 20/06/2022 13:22, Markus Armbruster wrote:
> Laurent Vivier <lvivier@redhat.com> writes:
> 
>> On 15/06/2022 13:46, Markus Armbruster wrote:
>>> Laurent Vivier <lvivier@redhat.com> writes:
>>>
>>>> On 13/05/2022 13:44, Markus Armbruster wrote:
>>>>> Laurent Vivier <lvivier@redhat.com> writes:
>>>>>
>>>>>> 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 netdev, multicast is detected
>>>>>> according to the IP address type.
>>>>>> "listen" and "connect" modes are managed by stream netdev. An optional
>>>>>> parameter "server" defines the mode (server by default)
>>>>>>
>>>>>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>>>>>> ---
>>>>>>     hmp-commands.hx |   2 +-
>>>>>>     net/clients.h   |   6 +
>>>>>>     net/dgram.c     | 630 ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>>     net/hub.c       |   2 +
>>>>>>     net/meson.build |   2 +
>>>>>>     net/net.c       |  24 +-
>>>>>>     net/stream.c    | 425 ++++++++++++++++++++++++++++++++
>>>>>>     qapi/net.json   |  38 ++-
>>>>>>     8 files changed, 1125 insertions(+), 4 deletions(-)
>>>>>>     create mode 100644 net/dgram.c
>>>>>>     create mode 100644 net/stream.c
>>>>>>
>> ...
>>>>>> diff --git a/net/net.c b/net/net.c
>>>>>> index 2aab7167316c..fd6b30a10c57 100644
>>>>>> --- a/net/net.c
>>>>>> +++ b/net/net.c
>>>>>> @@ -1015,6 +1015,8 @@ 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_STREAM]    = net_init_stream,
>>>>>> +        [NET_CLIENT_DRIVER_DGRAM]     = net_init_dgram,
>>>>>>     #ifdef CONFIG_VDE
>>>>>>             [NET_CLIENT_DRIVER_VDE]       = net_init_vde,
>>>>>>     #endif
>>>>>> @@ -1097,6 +1099,8 @@ void show_netdevs(void)
>>>>>>         int idx;
>>>>>>         const char *available_netdevs[] = {
>>>>>>             "socket",
>>>>>> +        "stream",
>>>>>> +        "dgram",
>>>>>>             "hubport",
>>>>>>             "tap",
>>>>>>     #ifdef CONFIG_SLIRP
>>>>>> @@ -1606,7 +1610,25 @@ int net_init_clients(Error **errp)
>>>>>>      */
>>>>>>     static bool netdev_is_modern(const char *optarg)
>>>>>>     {
>>>>>> -    return false;
>>>>>> +    static QemuOptsList dummy_opts = {
>>>>>> +        .name = "netdev",
>>>>>> +        .implied_opt_name = "type",
>>>>>> +        .head = QTAILQ_HEAD_INITIALIZER(dummy_opts.head),
>>>>>> +        .desc = { { } },
>>>>>> +    };
>>>>>> +    const char *netdev;
>>>>>> +    QemuOpts *opts;
>>>>>> +    bool is_modern;
>>>>>> +
>>>>>> +    opts = qemu_opts_parse(&dummy_opts, optarg, true, &error_fatal);
>>>>>> +    netdev = qemu_opt_get(opts, "type");
>>>>>> +
>>>>>> +    is_modern = strcmp(netdev, "stream") == 0 ||
>>>>>> +                strcmp(netdev, "dgram") == 0;
>>>>>
>>>>> Crashes when user neglects to pass "type".
>>>>
>>>> I think "type" is always passed because of the '.implied_opt_name = "type"'. Am I wrong?
>>>
>>> .implied_opt_name = "type" lets you shorten "type=T,..." to "T,...".  It
>>> doesn't make key "type" mandatory.  "-netdev id=foo" is still permitted.
>>> Even "-netdev ''" is.
>>
>>
>> In fact type is checked before by QAPI definition:
>>
>> { 'union': 'Netdev',
>>     'base': { 'id': 'str', 'type': 'NetClientDriver' },
>>     'discriminator': 'type',
>> ...
>>
>> As it's the discriminator it must be there.
>>
>>     $ qemu-system-x86_64 -netdev id=foo
>>     qemu-system-x86_64: -netdev id=foo: Parameter 'type' is missing
> 
> It does crash for me:
> 
>      (gdb) bt
>      #0  0x00007ffff4d25dcb in __strcmp_avx2 () at /lib64/libc.so.6
>      #1  0x0000555555b4574b in netdev_is_modern (optarg=0x7fffffffe2ae "id=foo")
>          at ../net/net.c:1626
>      #2  0x0000555555b457ad in net_client_parse
>          (opts_list=0x555556563780 <qemu_netdev_opts>, optarg=0x7fffffffe2ae "id=foo") at ../net/net.c:1636
>      #3  0x0000555555ad98de in qemu_init (argc=3, argv=0x7fffffffdf08, envp=0x0)
>          at ../softmmu/vl.c:2901
>      #4  0x0000555555842c01 in qemu_main (argc=3, argv=0x7fffffffdf08, envp=0x0)
>          at ../softmmu/main.c:35
>      #5  0x0000555555842c37 in main (argc=3, argv=0x7fffffffdf08)
>          at ../softmmu/main.c:45
>      (gdb) up
>      #1  0x0000555555b4574b in netdev_is_modern (optarg=0x7fffffffe2ae "id=foo")
>          at ../net/net.c:1626
>      1626	    is_modern = strcmp(netdev, "stream") == 0 ||
>      (gdb) p netdev
>      $1 = 0x0
> 
> This is
> 
>       https://github.com/patchew-project/qemu tags/patchew/20220512080932.735962-1-lvivier@redhat.com
> 
> I suspect you tested with your v3, which doesn't crash for me, either.
> 

Yes, thank you. So this is fixed now :)

Laurent

[RFC PATCH v2 4/8] net: stream: Don't ignore EINVAL on netdev socket connection

[Laurent Vivier]

From: Stefano Brivio <sbrivio@redhat.com>

Other errors are treated as failure by net_stream_client_init(),
but if connect() returns EINVAL, we'll fail silently. Remove the
related exception.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
[lvivier: applied to net/stream.c]
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 net/stream.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/stream.c b/net/stream.c
index fdc97ee43a56..12fc26b9f4c7 100644
--- a/net/stream.c
+++ b/net/stream.c
@@ -365,8 +365,7 @@ static int net_stream_client_init(NetClientState *peer,
                 if (errno == EINTR || errno == EWOULDBLOCK) {
                     /* continue */
                 } else if (errno == EINPROGRESS ||
-                           errno == EALREADY ||
-                           errno == EINVAL) {
+                           errno == EALREADY) {
                     break;
                 } else {
                     error_setg_errno(errp, errno, "can't connect socket");
-- 
2.35.3

Re: [RFC PATCH v2 4/8] net: stream: Don't ignore EINVAL on netdev socket connection

[Daniel P. Berrangé]

On Thu, May 12, 2022 at 10:09:28AM +0200, Laurent Vivier wrote:
> From: Stefano Brivio <sbrivio@redhat.com>
> 
> Other errors are treated as failure by net_stream_client_init(),
> but if connect() returns EINVAL, we'll fail silently. Remove the
> related exception.
> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
> [lvivier: applied to net/stream.c]
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  net/stream.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


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 :|

[RFC PATCH v2 5/8] net: stream: add unix socket

[Laurent Vivier]

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 net/stream.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 99 insertions(+), 7 deletions(-)

diff --git a/net/stream.c b/net/stream.c
index 12fc26b9f4c7..dca50508ed84 100644
--- a/net/stream.c
+++ b/net/stream.c
@@ -234,7 +234,7 @@ static NetStreamState *net_stream_fd_init_stream(NetClientState *peer,
 static void net_stream_accept(void *opaque)
 {
     NetStreamState *s = opaque;
-    struct sockaddr_in saddr;
+    struct sockaddr_storage saddr;
     socklen_t len;
     int fd;
 
@@ -252,9 +252,27 @@ static void net_stream_accept(void *opaque)
     s->fd = fd;
     s->nc.link_down = false;
     net_stream_connect(s);
-    snprintf(s->nc.info_str, sizeof(s->nc.info_str),
-             "connection from %s:%d",
-             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+    switch (saddr.ss_family) {
+    case AF_INET: {
+        struct sockaddr_in *saddr_in = (struct sockaddr_in *)&saddr;
+
+        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
+                 "connection from %s:%d",
+                 inet_ntoa(saddr_in->sin_addr), ntohs(saddr_in->sin_port));
+        break;
+    }
+    case AF_UNIX: {
+        struct sockaddr_un saddr_un;
+
+        len = sizeof(saddr_un);
+        getsockname(s->listen_fd, (struct sockaddr *)&saddr_un, &len);
+        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
+                 "connect from %s", saddr_un.sun_path);
+        break;
+    }
+    default:
+        g_assert_not_reached();
+    }
 }
 
 static int net_stream_server_init(NetClientState *peer,
@@ -295,8 +313,40 @@ static int net_stream_server_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);
@@ -382,6 +432,48 @@ static int net_stream_client_init(NetClientState *peer,
                                    ntohs(saddr_in.sin_port));
         break;
     }
+    case SOCKET_ADDRESS_TYPE_UNIX: {
+        struct sockaddr_un saddr_un;
+
+        saddr_un.sun_family = PF_UNIX;
+        ret = snprintf(saddr_un.sun_path, sizeof(saddr_un.sun_path), "%s",
+                       addr->u.q_unix.path);
+        if (ret < 0 || ret >= sizeof(saddr_un.sun_path)) {
+            error_setg(errp, "UNIX socket path '%s' is too long",
+                       addr->u.q_unix.path);
+            error_append_hint(errp, "Path must be less than %zu bytes\n",
+                              sizeof(saddr_un.sun_path));
+        }
+
+        fd = qemu_socket(PF_UNIX, SOCK_STREAM, 0);
+        if (fd < 0) {
+            error_setg_errno(errp, errno, "can't create stream socket");
+            return -1;
+        }
+        qemu_socket_set_nonblock(fd);
+
+        connected = 0;
+        for (;;) {
+            ret = connect(fd, (struct sockaddr *)&saddr_un, sizeof(saddr_un));
+            if (ret < 0) {
+                if (errno == EINTR || errno == EWOULDBLOCK) {
+                    /* continue */
+                } else if (errno == EAGAIN ||
+                           errno == EALREADY) {
+                    break;
+                } else {
+                    error_setg_errno(errp, errno, "can't connect socket");
+                    closesocket(fd);
+                    return -1;
+                }
+            } else {
+                connected = 1;
+                break;
+            }
+        }
+        info_str = g_strdup_printf(" connect to %s", saddr_un.sun_path);
+        break;
+    }
     case SOCKET_ADDRESS_TYPE_FD:
         fd = monitor_fd_param(monitor_cur(), addr->u.fd.str, errp);
         if (fd == -1) {
@@ -397,7 +489,7 @@ static int net_stream_client_init(NetClientState *peer,
         info_str = g_strdup_printf("connect to fd %d", fd);
         break;
     default:
-        error_setg(errp, "only support inet or fd type");
+        error_setg(errp, "only support inet, unix or fd type");
         return -1;
     }
 
-- 
2.35.3

[RFC PATCH v2 6/8] net: dgram: 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/dgram.c | 76 +++++++++++++++++++++++++++++++----------------------
 1 file changed, 45 insertions(+), 31 deletions(-)

diff --git a/net/dgram.c b/net/dgram.c
index aa4240501ed0..16b4d4c94c81 100644
--- a/net/dgram.c
+++ b/net/dgram.c
@@ -39,9 +39,8 @@ typedef struct NetDgramState {
     int listen_fd;
     int fd;
     SocketReadState rs;
-  /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
-    struct sockaddr_in dgram_dst;
-    IOHandler *send_fn;           /* differs between SOCK_STREAM/SOCK_DGRAM */
+    struct sockaddr *dgram_dst; /* contains destination iff connectionless */
+    IOHandler *send_fn;
     bool read_poll;               /* waiting to receive data? */
     bool write_poll;              /* waiting to transmit data? */
 } NetDgramState;
@@ -85,10 +84,9 @@ static ssize_t net_dgram_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);
         }
@@ -289,6 +287,8 @@ static void net_dgram_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 = {
@@ -305,7 +305,7 @@ static NetDgramState *net_dgram_fd_init_dgram(NetClientState *peer,
                                               SocketAddress *mcast,
                                               Error **errp)
 {
-    struct sockaddr_in saddr;
+    struct sockaddr_in *saddr = NULL;
     int newfd;
     NetClientState *nc;
     NetDgramState *s;
@@ -327,24 +327,25 @@ static NetDgramState *net_dgram_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_dgram_mcast_create(&saddr, NULL, errp);
+            newfd = net_dgram_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);
@@ -358,16 +359,13 @@ static NetDgramState *net_dgram_fd_init_dgram(NetClientState *peer,
     net_dgram_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),
                  "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), "fd=%d %s", fd,
                  SocketAddressType_str(sa_type));
     }
@@ -375,6 +373,7 @@ static NetDgramState *net_dgram_fd_init_dgram(NetClientState *peer,
     return s;
 
 err:
+    g_free(saddr);
     closesocket(fd);
     return NULL;
 }
@@ -420,21 +419,24 @@ static int net_dgram_mcast_init(NetClientState *peer,
 {
     NetDgramState *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_dgram_mcast_create(&saddr, NULL, errp);
+        fd = net_dgram_mcast_create(saddr, NULL, errp);
         if (fd < 0) {
+            g_free(saddr);
             return -1;
         }
     } else {
@@ -443,13 +445,15 @@ static int net_dgram_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_dgram_mcast_create(&saddr, &localaddr, errp);
+            fd = net_dgram_mcast_create(saddr, &localaddr, errp);
             if (fd < 0) {
+                g_free(saddr);
                 return -1;
             }
             break;
@@ -457,16 +461,19 @@ static int net_dgram_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;
         }
@@ -476,13 +483,16 @@ static int net_dgram_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), "mcast=%s:%d",
-             inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+             inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port));
+
     return 0;
 
 }
@@ -496,8 +506,8 @@ static int net_dgram_udp_init(NetClientState *peer,
 {
     NetDgramState *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) {
@@ -517,7 +527,7 @@ static int net_dgram_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) {
@@ -551,9 +561,12 @@ static int net_dgram_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("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;
     }
@@ -580,7 +593,8 @@ static int net_dgram_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);
-- 
2.35.3

[RFC PATCH v2 7/8] net: dgram: move mcast specific code from net_socket_fd_init_dgram()

[Laurent Vivier]

It is less complex to manage special cases directly in
net_dgram_mcast_init() and net_dgram_udp_init().

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 net/dgram.c | 143 +++++++++++++++++++++++++++-------------------------
 1 file changed, 73 insertions(+), 70 deletions(-)

diff --git a/net/dgram.c b/net/dgram.c
index 16b4d4c94c81..c0cf0410792e 100644
--- a/net/dgram.c
+++ b/net/dgram.c
@@ -301,52 +301,11 @@ static NetClientInfo net_dgram_socket_info = {
 static NetDgramState *net_dgram_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;
     NetDgramState *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_dgram_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);
 
@@ -358,24 +317,7 @@ static NetDgramState *net_dgram_fd_init_dgram(NetClientState *peer,
     net_socket_rs_init(&s->rs, net_dgram_rs_finalize, false);
     net_dgram_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),
-                 "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), "fd=%d %s", fd,
-                 SocketAddressType_str(sa_type));
-    }
-
     return s;
-
-err:
-    g_free(saddr);
-    closesocket(fd);
-    return NULL;
 }
 
 static void net_dgram_connect(void *opaque)
@@ -420,6 +362,7 @@ static int net_dgram_mcast_init(NetClientState *peer,
     NetDgramState *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");
@@ -439,6 +382,9 @@ static int net_dgram_mcast_init(NetClientState *peer,
             g_free(saddr);
             return -1;
         }
+        info_str = g_strdup_printf("mcast=%s:%d",
+                                   inet_ntoa(saddr->sin_addr),
+                                   ntohs(saddr->sin_port));
     } else {
         switch (local->type) {
         case SOCKET_ADDRESS_TYPE_INET: {
@@ -456,9 +402,14 @@ static int net_dgram_mcast_init(NetClientState *peer,
                 g_free(saddr);
                 return -1;
             }
+            info_str = g_strdup_printf("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);
@@ -471,7 +422,46 @@ static int net_dgram_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_dgram_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("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");
@@ -479,9 +469,7 @@ static int net_dgram_mcast_init(NetClientState *peer,
         }
     }
 
-    s = net_dgram_fd_init_dgram(peer, model, name, fd,
-                                 local->type == SOCKET_ADDRESS_TYPE_FD,
-                                 remote, errp);
+    s = net_dgram_fd_init_dgram(peer, model, name, fd, errp);
     if (!s) {
         g_free(saddr);
         return -1;
@@ -490,8 +478,8 @@ static int net_dgram_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), "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;
 
@@ -570,7 +558,10 @@ static int net_dgram_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;
@@ -581,23 +572,35 @@ static int net_dgram_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("fd=%d %s", fd,
+                                       SocketAddressType_str(sa_type));
+        } else {
+            info_str = g_strdup_printf("fd=%d", fd);
+        }
         break;
+    }
     default:
         error_setg(errp, "only support inet or fd type for local");
         return -1;
     }
 
-    s = net_dgram_fd_init_dgram(peer, model, name, fd, 0, NULL, errp);
+    s = net_dgram_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 v2 8/8] net: dgram: add unix socket

[Laurent Vivier]

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

diff --git a/net/dgram.c b/net/dgram.c
index c0cf0410792e..9f20bdbc163c 100644
--- a/net/dgram.c
+++ b/net/dgram.c
@@ -85,8 +85,15 @@ static ssize_t net_dgram_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);
         }
@@ -508,7 +515,7 @@ static int net_dgram_udp_init(NetClientState *peer,
         }
     } else {
         if (local->type != SOCKET_ADDRESS_TYPE_FD) {
-            error_setg(errp, "type=inet requires remote parameter");
+            error_setg(errp, "type=inet or unix require remote parameter");
             return -1;
         }
     }
@@ -558,6 +565,58 @@ static int net_dgram_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("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 v2 0/8] qapi: net: add unix socket type support to netdev backend

[Stefano Brivio]

On Thu, 12 May 2022 10:09:24 +0200
Laurent Vivier <lvivier@redhat.com> 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.
> 
> Two new netdev backends, "stream" and "dgram" are added, that are barely a copy of "socket"
> backend but they use the SocketAddress QAPI to provide socket parameters.
> And then they also implement unix sockets (TCP and UDP).
> 
> Some examples of CLI syntax:
> 
>   for TCP:
> 
>   -netdev stream,id=socket0,addr.type=inet,addr.host=localhost,addr.port=1234
>   -netdev stream,id=socket0,server=off,addr.type=inet,addr.host=localhost,addr.port=1234
> 
>   -netdev dgram,id=socket0,\
>           local.type=inet,local.host=localhost,local.port=1234,\
>           remote.type=inet,remote.host=localhost,remote.port=1235
> 
>   for UNIX:
> 
>   -netdev stream,id=socket0,addr.type=unix,addr.path=/tmp/qemu0
>   -netdev stream,id=socket0,server=off,addr.type=unix,addr.path=/tmp/qemu0
> 
>   -netdev dgram,id=socket0,\
>           local.type=unix,local.path=/tmp/qemu0,\
>           remote.type=unix,remote.path=/tmp/qemu1
> 
>   for FD:
> 
>   -netdev stream,id=socket0,addr.type=fd,addr.str=4
>   -netdev stream,id=socket0,server=off,addr.type=fd,addr.str=5
> 
>   -netdev dgram,id=socket0,local.type=fd,addr.str=4
> 
> v2:
>   - use "stream" and "dgram" rather than "socket-ng,mode=stream"
>     and ""socket-ng,mode=dgram"
>   - extract code to bypass qemu_opts_parse_noisily() to
>     a new patch
>   - do not ignore EINVAL (Stefano)
>   - fix "-net" option
> 
> 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 (7):
>   net: introduce convert_host_port()
>   qapi: net: introduce a way to bypass qemu_opts_parse_noisily()
>   qapi: net: add stream and dgram netdevs
>   net: stream: add unix socket
>   net: dgram: make dgram_dst generic
>   net: dgram: move mcast specific code from net_socket_fd_init_dgram()
>   net: dgram: add unix socket
> 
> Stefano Brivio (1):
>   net: stream: Don't ignore EINVAL on netdev socket connection

Except for 4/8:
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>

Except for 6/8 to 8/8:
Tested-by: Stefano Brivio <sbrivio@redhat.com>

-- 
Stefano