int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid, uint8_t type,
uint8_t **opt, size_t *optlen);
-void dhcp_packet_append_ip_headers(DHCPPacket *packet, uint16_t len);
+uint16_t dhcp_packet_checksum(void *buf, int len);
+
+void dhcp_packet_append_ip_headers(DHCPPacket *packet, be32_t source_addr,
+ uint16_t source, be32_t destination_addr,
+ uint16_t destination, uint16_t len);
int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum);