hostapd: Check the bridge if ioctl SIOCBRADDIF fails

If ioctl() returns EBUSY on the command SIOCBRADDIF, the interface might
have already been added to the bridge by an external operation (e.g.,
netifd in OpenWrt), and linux_br_add_if() should not indicate an error.

Check whether the interface is correctly brigded when ioctl()
returns EBUSY and if so, report success.

Signed-off-by: Michael-CY Lee <michael-cy.lee@mediatek.com>

diff --git a/src/drivers/linux_ioctl.c b/src/drivers/linux_ioctl.c
index 7edb9df2edd49a3bfafec49ef1b0307ebc99cb6e..29abc0c59e8383ec17240b57a6852869982238ba 100644 (file)
--- a/src/drivers/linux_ioctl.c
+++ b/src/drivers/linux_ioctl.c
@@ -161,11 +161,20 @@ int linux_br_add_if(int sock, const char *brname, const char *ifname)
        ifr.ifr_ifindex = ifindex;
        if (ioctl(sock, SIOCBRADDIF, &ifr) < 0) {
                int saved_errno = errno;
+               char in_br[IFNAMSIZ];
 
                wpa_printf(MSG_DEBUG, "Could not add interface %s into bridge "
                           "%s: %s", ifname, brname, strerror(errno));
                errno = saved_errno;
-               return -1;
+
+               /* If ioctl() returns EBUSY when adding an interface into the
+                * bridge, the interface might have already been added by an
+                * external operation, so check whether the interface is
+                * currently on the right bridge and ignore the error if it is.
+                */
+               if (errno != EBUSY || linux_br_get(in_br, ifname) != 0 ||
+                   os_strcmp(in_br, brname) != 0)
+                       return -1;
        }
 
        return 0;