NA0
NA0.a_family = RIP_AF_AUTH;
NA0.a_type = RIP_AUTH_PW;
memcpy(NA0.au.au_pw, passwd, RIP_AUTH_PW_LEN);
NA0.a_family = RIP_AF_AUTH;
NA0.a_type = RIP_AUTH_MD5;
NA0.au.a_md5.md5_keyid = (int8_t)keyid;
NA0.au.a_md5.md5_auth_len = RIP_AUTH_MD5_KEY_LEN;
NA0.au.a_md5.md5_seqno = 0;
NA0.au.a_md5.md5_pkt_len = htons(cc);