On Wed, Mar 07, 2012 at 06:48:03AM +0800, Amos Kong wrote:
> Introduce tcp_client_start() by moving original code in
> tcp_start_outgoing_migration().
>
> Signed-off-by: Amos Kong <akong@xxxxxxxxxx>
> ---
> net.c | 41 +++++++++++++++++++++++++++++++++++++++++
> qemu_socket.h | 1 +
> 2 files changed, 42 insertions(+), 0 deletions(-)
>
> diff --git a/net.c b/net.c
> index e90ff23..9afb0d1 100644
> --- a/net.c
> +++ b/net.c
> @@ -127,6 +127,47 @@ int tcp_server_start(const char *str, int *fd)
> return ret;
> }
>
> +int tcp_client_start(const char *str, int *fd)
> +{
> + struct sockaddr_in saddr;
> + int ret;
> +
> + *fd = -1;
> + 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);
> +
> + for (;;) {
> + ret = connect(*fd, (struct sockaddr *)&saddr, sizeof(saddr));
> + if (ret < 0) {
> + ret = -socket_error();
> + if (ret == -EINPROGRESS) {
> + break;
The previous implementation and your next patch seem to be expecting a break on
-EWOULDBLOCK/-EAGAIN as well. Was the behavior changed on purpose? I'm not
sure what the proper handling is for -EAGAIN: whether a non-blocking connect()
can eventually succeed or not. I suspect that it's not, but that previously we
treated it synonymously with -EINPROGRESS, then eventually got an error via
getsockopt() before failing the migration. If so, we're now changing the
behavior to retry until successful, but given the man page entry I don't
think that's a good idea since you might block indefinitely:
EAGAIN No more free local ports or insufficient
entries in the routing cache. For AF_INET
see the description of
/proc/sys/net/ipv4/ip_local_port_range
ip(7) for information on how to increase
the number of local ports.
> +#ifdef _WIN32
> + } else if (ret == -WSAEALREADY || ret == -WSAEINVAL) {
> + break;
> +#endif
> + } else if (ret != -EINTR && ret != -EWOULDBLOCK) {
> + perror("connect");
> + closesocket(*fd);
> + return ret;
> + }
> + } else {
> + break;
> + }
> + }
> +
> + return ret;
> +}
> +
> 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 d612793..9246578 100644
> --- a/qemu_socket.h
> +++ b/qemu_socket.h
> @@ -55,6 +55,7 @@ int unix_connect_opts(QemuOpts *opts);
> int unix_connect(const char *path);
>
> int tcp_server_start(const char *str, int *fd);
> +int tcp_client_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);
>
>
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