wext: handle mode switches correctly for mac80211

Since mac80211 requires that the device be !IFF_UP to change the mode
(and I think the old prism54 fullmac driver does too), do that.  This
shouldn't harm fullmac devices since they can handle mode switches on
the fly and usually don't care about up/down that much.

diff --git a/src/drivers/driver_wext.c b/src/drivers/driver_wext.c
index 1226b94..c9d7399 100644 (file)
--- a/src/drivers/driver_wext.c
+++ b/src/drivers/driver_wext.c
@@ -2151,17 +2151,54 @@ int wpa_driver_wext_set_mode(void *priv, int mode)
 {
        struct wpa_driver_wext_data *drv = priv;
        struct iwreq iwr;
-       int ret = 0;
+       int ret = -1, flags;
+       unsigned int new_mode = mode ? IW_MODE_ADHOC : IW_MODE_INFRA;
 
        os_memset(&iwr, 0, sizeof(iwr));
        os_strlcpy(iwr.ifr_name, drv->ifname, IFNAMSIZ);
-       iwr.u.mode = mode ? IW_MODE_ADHOC : IW_MODE_INFRA;
+       iwr.u.mode = new_mode;
+       if (ioctl(drv->ioctl_sock, SIOCSIWMODE, &iwr) == 0) {
+               ret = 0;
+               goto done;
+       }
 
-       if (ioctl(drv->ioctl_sock, SIOCSIWMODE, &iwr) < 0) {
+       if (errno != EBUSY) {
                perror("ioctl[SIOCSIWMODE]");
-               ret = -1;
+               goto done;
+       }
+
+       /* mac80211 doesn't allow mode changes while the device is up, so if
+        * the device isn't in the mode we're about to change to, take device
+        * down, try to set the mode again, and bring it back up.
+        */
+       if (ioctl(drv->ioctl_sock, SIOCGIWMODE, &iwr) < 0) {
+               perror("ioctl[SIOCGIWMODE]");
+               goto done;
+       }
+
+       if (iwr.u.mode == new_mode) {
+               ret = 0;
+               goto done;
+       }
+
+       if (wpa_driver_wext_get_ifflags(drv, &flags) == 0) {
+               (void) wpa_driver_wext_set_ifflags(drv, flags & ~IFF_UP);
+
+               /* Try to set the mode again while the interface is down */
+               iwr.u.mode = new_mode;
+               if (ioctl(drv->ioctl_sock, SIOCSIWMODE, &iwr) < 0)
+                       perror("ioctl[SIOCSIWMODE]");
+               else
+                       ret = 0;
+
+               /* Ignore return value of get_ifflags to ensure that the device
+                * is always up like it was before this function was called.
+                */
+               (void) wpa_driver_wext_get_ifflags(drv, &flags);
+               (void) wpa_driver_wext_set_ifflags(drv, flags | IFF_UP);
        }
 
+done:
        return ret;
 }