#define ip6_addr_set_solicitednode(ip6addr, if_id) do{(ip6addr)->addr[0] = PP_HTONL(0xff020000UL); \
(ip6addr)->addr[1] = 0; \
(ip6addr)->addr[2] = PP_HTONL(0x00000001UL); \
(ip6addr)->addr[3] = (PP_HTONL(0xff000000UL) | (if_id)); \
ip6_addr_clear_zone(ip6addr); }while(0)