Re: [Qemu-devel] [PATCH v3 1/9] net: introduce tcp_server_start()

[Michael Roth <mdroth@linux.vnet.ibm.com>]

On Wed, Mar 07, 2012 at 06:47:45AM +0800, Amos Kong wrote:
> Introduce tcp_server_start() by moving original code in
> tcp_start_incoming_migration().
> 
> Signed-off-by: Amos Kong <akong@redhat.com>
> ---
>  net.c         |   28 ++++++++++++++++++++++++++++
>  qemu_socket.h |    2 ++
>  2 files changed, 30 insertions(+), 0 deletions(-)
> 
> diff --git a/net.c b/net.c
> index c34474f..e90ff23 100644
> --- a/net.c
> +++ b/net.c
> @@ -99,6 +99,34 @@ static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)
>      return 0;
>  }
> 
> +int tcp_server_start(const char *str, int *fd)
> +{
> +    int val, ret;
> +    struct sockaddr_in saddr;
> +
> +    if (parse_host_port(&saddr, str) < 0) {
> +        error_report("invalid host/port combination: %s", str);
> +        return -EINVAL;
> +    }
> +
> +    *fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
> +    if (fd < 0) {
> +        perror("socket");
> +        return -1;
> +    }
> +    socket_set_nonblock(*fd);
> +
> +    /* allow fast reuse */
> +    val = 1;
> +    setsockopt(*fd, SOL_SOCKET, SO_REUSEADDR, (const char *)&val, sizeof(val));
> +
> +    ret = bind(*fd, (struct sockaddr *)&saddr, sizeof(saddr));
> +    if (ret < 0) {
> +        closesocket(*fd);
> +    }
> +    return ret;
> +}
> +

I would combine this with patch 2, since it provides context for why
this function is being added. Would also do the same for 3 and 4.

I see client the client implementation you need to pass fd back by
reference since ret can be set to EINPROGRESS/EWOULDBLOCK on success,
but here it looks like fd is only value if ret=0, so might as well just
pass back the fd as the function return value.

Also, is there any reason we can't re-use
qemu-sockets.c:inet_listen()/qemu-sockets.c:inet_connect()? AFAICT they
serve the same purpose, and already include some of the work from your
PATCH #6.

>  int parse_host_port(struct sockaddr_in *saddr, const char *str)
>  {
>      char buf[512];
> diff --git a/qemu_socket.h b/qemu_socket.h
> index fe4cf6c..d612793 100644
> --- a/qemu_socket.h
> +++ b/qemu_socket.h
> @@ -54,6 +54,8 @@ int unix_listen(const char *path, char *ostr, int olen);
>  int unix_connect_opts(QemuOpts *opts);
>  int unix_connect(const char *path);
> 
> +int tcp_server_start(const char *str, int *fd);
> +
>  /* Old, ipv4 only bits.  Don't use for new code. */
>  int parse_host_port(struct sockaddr_in *saddr, const char *str);
>  int socket_init(void);
> 
>