[NET]: Fix multicast device ioctl checks

SIOCADDMULTI/SIOCDELMULTI check whether the driver has a set_multicast_list
method to determine whether it supports multicast. Drivers implementing
secondary unicast support use set_rx_mode however.

Check for both dev->set_multicast_mode and dev->set_rx_mode to determine
multicast capabilities.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -3329,7 +3329,7 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
 			return -EOPNOTSUPP;
 
 		case SIOCADDMULTI:
-			if (!dev->set_multicast_list ||
+			if ((!dev->set_multicast_list && !dev->set_rx_mode) ||
 			    ifr->ifr_hwaddr.sa_family != AF_UNSPEC)
 				return -EINVAL;
 			if (!netif_device_present(dev))
@@ -3338,7 +3338,7 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
 					  dev->addr_len, 1);
 
 		case SIOCDELMULTI:
-			if (!dev->set_multicast_list ||
+			if ((!dev->set_multicast_list && !dev->set_rx_mode) ||
 			    ifr->ifr_hwaddr.sa_family != AF_UNSPEC)
 				return -EINVAL;
 			if (!netif_device_present(dev))