drop received packet if it is not received on the correct interface
drop received packet if it is not received on the correct interface

gebart/libcoap,thecodemaiden/libcoap-fork,sgso/libcoap,authmillenon/libcoap,fredericgermain/libcoap,nmacs/libcoap,fredericgermain/libcoap,gebart/libcoap,nmacs/libcoap,RIOT-OS/libcoap,gebart/libcoap,nmacs/libcoap,fredericgermain/libcoap,RIOT-OS/libcoap,sgso/libcoap,sgso/libcoap,authmillenon/libcoap,thecodemaiden/libcoap-fork,authmillenon/libcoap