#ifndef __ETH_UDP_H__
#define __ETH_UDP_H__

#include "stdint.h"

#define UDP_CHECKSUM_ENABLE 1

struct udp_cfg_s {
    char *mac_src;
    char *mac_dst;
    char *ip_src;
    char *ip_dst;
    char *port_src;
    char *port_dst;
};

struct udp_header_s {
    uint8_t preamble[2];         // fixed 55 D5
    /* MAC */
    uint8_t mac_dst[6];
    uint8_t mac_src[6];
    uint8_t ip_type[2];          // 08 00 for IPv4 type
    /* IP */
    uint8_t ver_head_length;     // 0x45 for IPv4 and head length is 5*4=20 bytes
    uint8_t tos;                 // type of service, normal 0
    uint8_t ip_total_length[2];  // 28 + user data length, e.g. 00 20 for 32 bytes
    uint8_t id[2];
    uint8_t offset[2];
    uint8_t ttl;                 // time to live, normal 0x80
    uint8_t prototal;            // 0x11 for UDP prototal
    uint8_t ip_checksum[2];      // normal 00 00
    uint8_t ip_src[4];           // e.g. C0 A8 02 18 is for 192.168.2.24
    uint8_t ip_dst[4];           // e.g. C0 A8 02 20 is for 192.168.2.32
    /* UDP */
    uint8_t port_src[2];         // e.g. 26 E5 is for 9957
    uint8_t port_dst[2];         // e.g. 0E D3 is for 3795
    uint8_t udp_total_length[2]; // 8 + user data length, e.g. 00 0C for 12 bytes
    uint8_t udp_checksum[2];
};

#ifdef __cplusplus
extern "C" {
#endif

int udp_create_default(struct udp_cfg_s *cfg, struct udp_header_s *udp);
uint32_t *udp_copy_header(uint32_t *dst, struct udp_header_s *udp);
uint16_t udp_pack_data(struct udp_header_s *udp, uint16_t length);

#ifdef __cplusplus
}
#endif

#endif /* __ETH_UDP_H__ */