#include <netinet/ip.h>
#include <netinet/ether.h>

#include "utils.h"
#include "g_vxlan.h"

void g_vxlan_set_packet_dir(struct g_vxlan *hdr, int dir_is_e2i)
{
    hdr->dir_is_e2i = (!!dir_is_e2i);
}

void g_vxlan_set_chain_index(struct g_vxlan *hdr, int chain_index)
{
    hdr->chain_index = (0x1f & chain_index);
}

void g_vxlan_set_traffic_type(struct g_vxlan *hdr, int traffic_is_decrypted)
{
    hdr->traffic_is_decrypted = (!!traffic_is_decrypted);
}

int g_vxlan_get_packet_dir(struct g_vxlan *hdr)
{
    return (!!hdr->dir_is_e2i);
}

int g_vxlan_get_chain_index(struct g_vxlan *hdr)
{
    return hdr->chain_index;
}

int g_vxlan_get_traffic_type(struct g_vxlan *hdr)
{
    return (!!hdr->traffic_is_decrypted);
}

// return  0 : success
// return -1 : error
int g_vxlan_decode(struct g_vxlan **g_vxlan_hdr, const char *raw_data, int raw_len)
{
    if (raw_len <= (int)(sizeof(struct ethhdr) + sizeof(struct ip) + sizeof(struct udp_hdr) + sizeof(struct g_vxlan)))
    {
        return -1;
    }

    struct ethhdr *eth_hdr = (struct ethhdr *)raw_data;
    if (eth_hdr->h_proto != htons(ETH_P_IP))
    {
        return -1;
    }

    struct ip *ip_hdr = (struct ip *)((char *)eth_hdr + sizeof(struct ethhdr));
    if (ip_hdr->ip_p != IPPROTO_UDP)
    {
        return -1;
    }

    struct udp_hdr *udp_hdr = (struct udp_hdr *)((char *)ip_hdr + sizeof(struct ip));
    if (udp_hdr->uh_dport != htons(4789))
    {
        return -1;
    }

    *g_vxlan_hdr = (struct g_vxlan *)((char *)udp_hdr + sizeof(struct udp_hdr));

    return 0;
}