Re: [Qemu-devel] [PATCH v2] net: add the support for -netdev socket, listen

[Zhi Yong Wu]

On Fri, Feb 24, 2012 at 11:05 PM, Anthony Liguori <address@hidden> wrote:
> On 02/18/2012 03:19 AM, address@hidden wrote:
>>
>> From: Zhi Yong Wu<address@hidden>
>>
>> The -net socket,listen option does not work with the newer -netdev
>> syntax:
>> http://lists.gnu.org/archive/html/qemu-devel/2011-11/msg01508.html
>>
>> This patch makes it work now.
>>
>> Signed-off-by: Zhi Yong Wu<address@hidden>
>> ---
>>  net.c        |   26 +++++++++++++++++++++
>>  net.h        |    2 +
>>  net/socket.c |   72
>> +++++++++++++++++++++++++++++++++++++++++++++-------------
>>  3 files changed, 84 insertions(+), 16 deletions(-)
>>
>> diff --git a/net.c b/net.c
>> index c34474f..60e7b35 100644
>> --- a/net.c
>> +++ b/net.c
>> @@ -190,6 +190,32 @@ static ssize_t
>> qemu_deliver_packet_iov(VLANClientState *sender,
>>                                         int iovcnt,
>>                                         void *opaque);
>>
>> +VLANClientState *qemu_lookup_net_client(VLANState *vlan,
>> +                                        const char *name)
>> +{
>> +    VLANClientState *vc = NULL;
>> +
>> +    if (vlan) {
>> +        QTAILQ_FOREACH(vc,&vlan->clients, next) {
>>
>> +            if (!strcmp(vc->name, name)) {
>> +                break;
>> +            }
>> +        }
>> +    } else {
>> +        QTAILQ_FOREACH(vc,&non_vlan_clients, next) {
>>
>> +            if (!strcmp(vc->name, name)) {
>> +                break;
>> +            }
>> +        }
>> +    }
>> +
>> +    if (!vc) {
>> +        return NULL;
>> +    }
>> +
>> +    return vc;
>> +}
>> +
>>  VLANClientState *qemu_new_net_client(NetClientInfo *info,
>>                                       VLANState *vlan,
>>                                       VLANClientState *peer,
>> diff --git a/net.h b/net.h
>> index 75a8c15..7f73160 100644
>> --- a/net.h
>> +++ b/net.h
>> @@ -90,6 +90,8 @@ struct VLANState {
>>
>>  VLANState *qemu_find_vlan(int id, int allocate);
>>  VLANClientState *qemu_find_netdev(const char *id);
>> +VLANClientState *qemu_lookup_net_client(VLANState *vlan,
>> +                                        const char *name);
>>  VLANClientState *qemu_new_net_client(NetClientInfo *info,
>>                                       VLANState *vlan,
>>                                       VLANClientState *peer,
>> diff --git a/net/socket.c b/net/socket.c
>> index d4c2002..3ecee59 100644
>> --- a/net/socket.c
>> +++ b/net/socket.c
>> @@ -43,6 +43,7 @@ typedef struct NetSocketState {
>>  } NetSocketState;
>>
>>  typedef struct NetSocketListenState {
>> +    VLANClientState *nc;
>>      VLANState *vlan;
>>      char *model;
>>      char *name;
>> @@ -247,7 +248,8 @@ static NetClientInfo net_dgram_socket_info = {
>>  static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>>                                                  const char *model,
>>                                                  const char *name,
>> -                                                int fd, int is_connected)
>> +                                                int fd, int is_connected,
>> +                                                int is_listen)
>>  {
>>      struct sockaddr_in saddr;
>>      int newfd;
>> @@ -286,15 +288,28 @@ static NetSocketState
>> *net_socket_fd_init_dgram(VLANState *vlan,
>>          }
>>      }
>>
>> -    nc = qemu_new_net_client(&net_dgram_socket_info, vlan, NULL, model,
>> name);
>> +
>> +    if (!is_listen || (is_listen&&  !is_connected)) {
>>
>> +        nc = qemu_new_net_client(&net_dgram_socket_info,
>> +                                 vlan, NULL, model, name);
>> +    } else {
>> +        nc = qemu_lookup_net_client(vlan, name);
>> +        if (!nc) {
>> +            goto err;
>> +        }
>> +    }
>> +
>> +    s = DO_UPCAST(NetSocketState, nc, nc);
>> +
>> +    if (is_listen&&  !is_connected) {
>>
>> +        return s;
>> +    }
>>
>>      snprintf(nc->info_str, sizeof(nc->info_str),
>>              "socket: fd=%d (%s mcast=%s:%d)",
>>              fd, is_connected ? "cloned" : "",
>>              inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
>>
>> -    s = DO_UPCAST(NetSocketState, nc, nc);
>> -
>>      s->fd = fd;
>>
>>      qemu_set_fd_handler(s->fd, net_socket_send_dgram, NULL, s);
>> @@ -325,16 +340,29 @@ static NetClientInfo net_socket_info = {
>>  static NetSocketState *net_socket_fd_init_stream(VLANState *vlan,
>>                                                   const char *model,
>>                                                   const char *name,
>> -                                                 int fd, int
>> is_connected)
>> +                                                 int fd, int
>> is_connected,
>> +                                                 int is_listen)
>>  {
>>      VLANClientState *nc;
>>      NetSocketState *s;
>>
>> -    nc = qemu_new_net_client(&net_socket_info, vlan, NULL, model, name);
>> +    if (!is_listen || (is_listen&&  !is_connected)) {
>>
>> +        nc = qemu_new_net_client(&net_socket_info, vlan, NULL, model,
>> name);
>> +    } else {
>> +        nc = qemu_lookup_net_client(vlan, name);
>> +        if (!nc) {
>> +            return NULL;
>> +        }
>> +    }
>> +
>> +    s = DO_UPCAST(NetSocketState, nc, nc);
>> +
>> +    if (is_listen&&  !is_connected) {
>>
>> +        return s;
>> +    }
>>
>>      snprintf(nc->info_str, sizeof(nc->info_str), "socket: fd=%d", fd);
>>
>> -    s = DO_UPCAST(NetSocketState, nc, nc);
>>
>>      s->fd = fd;
>>
>> @@ -348,7 +376,8 @@ static NetSocketState
>> *net_socket_fd_init_stream(VLANState *vlan,
>>
>>  static NetSocketState *net_socket_fd_init(VLANState *vlan,
>>                                            const char *model, const char
>> *name,
>> -                                          int fd, int is_connected)
>> +                                          int fd, int is_connected,
>> +                                          int is_listen)
>>  {
>>      int so_type = -1, optlen=sizeof(so_type);
>>
>> @@ -361,13 +390,16 @@ static NetSocketState *net_socket_fd_init(VLANState
>> *vlan,
>>      }
>>      switch(so_type) {
>>      case SOCK_DGRAM:
>> -        return net_socket_fd_init_dgram(vlan, model, name, fd,
>> is_connected);
>> +        return net_socket_fd_init_dgram(vlan, model,
>> +                                        name, fd, is_connected,
>> is_listen);
>>      case SOCK_STREAM:
>> -        return net_socket_fd_init_stream(vlan, model, name, fd,
>> is_connected);
>> +        return net_socket_fd_init_stream(vlan, model,
>> +                                         name, fd, is_connected,
>> is_listen);
>>      default:
>>          /* who knows ... this could be a eg. a pty, do warn and continue
>> as stream */
>>          fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not
>> SOCK_DGRAM or SOCK_STREAM\n", so_type, fd);
>> -        return net_socket_fd_init_stream(vlan, model, name, fd,
>> is_connected);
>> +        return net_socket_fd_init_stream(vlan, model,
>> +                                         name, fd, is_connected,
>> is_listen);
>>      }
>>      return NULL;
>>  }
>> @@ -389,14 +421,17 @@ static void net_socket_accept(void *opaque)
>>              break;
>>          }
>>      }
>> -    s1 = net_socket_fd_init(s->vlan, s->model, s->name, fd, 1);
>> +
>> +    s1 = net_socket_fd_init(s->vlan, s->model, s->name, fd, 1, 1);
>>      if (s1) {
>>          snprintf(s1->nc.info_str, sizeof(s1->nc.info_str),
>>                   "socket: connection from %s:%d",
>>                   inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
>> +        s1->nc.link_down = false;
>
>
> I find this to be a little odd.  Nothing else uses link_down link this.  Why
> are you setting this flag?
s1->nc.link_down = false this mean that the link are re-up. In current
upstream, the option -netdev socket,listen can not work. The reason is
that when network card is created, it will look for its peer net
client. Because socket is still in listen state, its net client object
will not be created until this socket accept the client's request.
This will cause that network card fails to look for its peer net
client. This is the root reason for the option -netdev socket,listen
can not work.

In this patch, the net client object for socket is created in advance
when socket is in listen state. This void that network card fail to
look for its peer net client object. As you've known, at the moment,
the client request has not arrived, and the socket is still in listen
state, so the link state is set to down state to reject packet
trasmission. When the client request arrives, socket accept its
request, and the link state is re-set to up state, data packets can be
trasmitted now.

>
> Regards,
>
> Anthony Liguori
>



-- 
Regards,

Zhi Yong Wu