DHCP_SYNC_HMAC_LEN
u_int8_t hmac[2][DHCP_SYNC_HMAC_LEN];
memcpy(hmac[0], hdr->sh_hmac, DHCP_SYNC_HMAC_LEN);
explicit_bzero(hdr->sh_hmac, DHCP_SYNC_HMAC_LEN);
if (bcmp(hmac[0], hmac[1], DHCP_SYNC_HMAC_LEN) != 0)
u_int8_t sh_hmac[DHCP_SYNC_HMAC_LEN];