[PATCH] driver_nl80211: set_country fix

[Johannes Berg]

On Sun, 2013-06-23 at 16:07 +0300, Igal Chernobelsky wrote:
> Regulatory domain setting may take some time.
> Getting reg domain info immediately after reg domain setting returns
> invalid reg domain data. Loop is added to read reg domain info back and
> to compare set country. If read country does not match, fail to 1 sec sleep
> and retry get/compare again.
> 
> Signed-off-by: Igal Chernobelsky <igalc at ti.com>
> ---
>  src/drivers/driver_nl80211.c |   53 +++++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 52 insertions(+), 1 deletions(-)
> 
> diff --git a/src/drivers/driver_nl80211.c b/src/drivers/driver_nl80211.c
> index f705a0c..cc5084b 100644
> --- a/src/drivers/driver_nl80211.c
> +++ b/src/drivers/driver_nl80211.c
> @@ -2689,6 +2689,37 @@ static void wpa_driver_nl80211_event_receive(int sock, void *eloop_ctx,
>  }
>  
> 
> +static int get_country_handler(struct nl_msg *msg, void *arg)
> +{
> +	char * alpha2 = (char *) arg;
> +	struct nlattr *tb_msg[NL80211_ATTR_MAX + 1];
> +	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
> +
> +	nla_parse(tb_msg, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
> +		  genlmsg_attrlen(gnlh, 0), NULL);
> +	if (!tb_msg[NL80211_ATTR_REG_ALPHA2]) {
> +		wpa_printf(MSG_DEBUG, "nl80211: No country information "
> +			   "available");
> +		return NL_SKIP;
> +	}
> +	os_memcpy(alpha2, nla_data(tb_msg[NL80211_ATTR_REG_ALPHA2]), 3);
> +	return NL_SKIP;
> +}
> +
> +static int nl80211_get_country(struct wpa_driver_nl80211_data *drv,
> +				char *alpha2)
> +{
> +	struct nl_msg *msg;
> +
> +	msg = nlmsg_alloc();
> +	if (!msg)
> +		return -ENOMEM;
> +
> +	nl80211_cmd(drv, msg, 0, NL80211_CMD_GET_REG);
> +	return send_and_recv_msgs(drv, msg, get_country_handler, alpha2);
> +}
> +
> +
>  /**
>   * wpa_driver_nl80211_set_country - ask nl80211 to set the regulatory domain
>   * @priv: driver_nl80211 private data
> @@ -2703,7 +2734,10 @@ static int wpa_driver_nl80211_set_country(void *priv, const char *alpha2_arg)
>  	struct i802_bss *bss = priv;
>  	struct wpa_driver_nl80211_data *drv = bss->drv;
>  	char alpha2[3];
> +	char alpha2_res[3];
>  	struct nl_msg *msg;
> +	int count;
> +	int ret;
>  
>  	msg = nlmsg_alloc();
>  	if (!msg)
> @@ -2718,7 +2752,24 @@ static int wpa_driver_nl80211_set_country(void *priv, const char *alpha2_arg)
>  	NLA_PUT_STRING(msg, NL80211_ATTR_REG_ALPHA2, alpha2);
>  	if (send_and_recv_msgs(drv, msg, NULL, NULL))
>  		return -EINVAL;
> -	return 0;
> +
> +	/* Validate coutry setting and retry up to 3 times if not match */
> +	for (count = 0; count < 3; count++) {
> +		os_memset(alpha2_res, 0, sizeof(alpha2));
> +		ret = nl80211_get_country(drv, alpha2_res);
> +		if (ret)
> +			return ret;
> +		if (os_strncmp(alpha2, alpha2_res, 3)) {
> +			wpa_printf(MSG_DEBUG, "wpa_driver_nl80211_set_country:"
> +					"retry country set after delay");
> +			os_sleep(1, 0);
> +		} else {
> +			/* contry set is completed */
> +			return 0;
> +		}
> +	}
> +	wpa_printf(MSG_ERROR, "wpa_driver_nl80211_set_country: failed");
> +	return -EINVAL;

I don't think this is really a failure -- if you request a country but
the kernel already has one it might create an intersection etc. Might
want to even abort the loop in that case.

johannes