DST_MAC
MAP_FLAG(LOC_MAC, DST_MAC);
COPY_FIELD(LOC_MAC, loc_mac, DST_MAC);
MAP_FILTER_TO_MCDI_FLAG(LOC_MAC, DST_MAC, encap_type);
uint64_t smac = SRC_MAC, dmac = DST_MAC;
"ip -4 neigh add " DST_ADDR " lladdr " DST_MAC " dev " RX_NAME);