TEST_IPV6
SYS(out_remove_ipv4, "ip -6 addr add %s dev lo", TEST_IPV6);
SYS_NOFAIL("ip -6 addr del %s dev lo", TEST_IPV6);
SYS(fail, "ip -6 addr add %s/128 nodad dev %s1", TEST_IPV6, TEST_IF_PREFIX);
#define SRC6_REWRITE_IP TEST_IPV6