//http://www.saminiir.com/lets-code-tcp-ip-stack-1-ethernet-arp/
//https://openvpn.net/tuntap

#ifdef PLATFORM_LINUX

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/ioctl.h>

#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <linux/if_tun.h>
#include <linux/if.h>

#include "netdev.h"

int fd;

int tap_transmit(const void * p_data, uint16_t p_len)
{
    write(fd,p_data,p_len);
    return 0;
}

int main(int argc, char **argv)
{
    int err;
    char dev[]="tap0";
    struct ifreq ifr;

    if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) {
        printf("Cannot open TUN/TAP dev\n");
        exit(1);
    }


    memset(&ifr, 0, sizeof(ifr));
    ifr.ifr_flags = IFF_TAP | IFF_NO_PI; 
    strncpy(ifr.ifr_name, dev,IFNAMSIZ);

    if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){
        printf("ioctl failed for TAP\n");
         close(fd);
         return err;
    }


    struct netdev net_dev;


    uint8_t mac[6];
    mac[0]=0x7a;
    mac[1]=0xa4;
    mac[2]=0x7b;
    mac[3]=0x72;
    mac[4]=0x56;
    mac[5]=0xa2;

    memcpy(net_dev.hwaddr,mac,6);	                // use mac obtained from device
    net_dev.ip=(192<<0)+(168<<8)+(0<<16)+(20<<24); // 192.168.0.20 // TODO: not hardcode!
    net_dev.transmit=tap_transmit;

    uint8_t buf[1024];

    while(1)
    {
        uint32_t len=read(fd,buf,1024);

        if(len==-1)
        {
            printf("read error: %s \n",strerror(errno));
        }

        printf("read %d bytes\n",len);
        net_incoming(&net_dev,buf);
    }

    return 0;
}


#endif