IP4_ADDR_VETH1
SYS(fail_close_client_ns, "ip -4 addr add " IP4_ADDR_VETH1 "/24 dev veth1");
cfg->tunnel_client_addr = IP4_ADDR_VETH1;
"ip -4 addr add " IP4_ADDR_VETH1 "/24 dev veth1");
.tunnel_client_addr = IP4_ADDR_VETH1,