NAT64_MIN_PORT
pg->base_port = NAT64_MIN_PORT + 64 * pg_idx;
if (port < NAT64_MIN_PORT)
port -= NAT64_MIN_PORT;
if (pg->base_port == NAT64_MIN_PORT)
idx = (pg->base_port - NAT64_MIN_PORT) / 64;
idx->port = NAT64_MIN_PORT;
pg_idx = (idx->port - NAT64_MIN_PORT) / 64;
idx.port = NAT64_MIN_PORT;
idx.port < NAT64_MIN_PORT) {