// Taken from ax25-tools 0.0.10-rc4 kissattach.c
// SPDX-License-Identifier: GPL-2.0-only
#include <stdio.h>
#define __USE_XOPEN
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>
#include <fcntl.h>
#include <signal.h>
#include <ctype.h>
#include <netdb.h>
#include <syslog.h>
#include <errno.h>

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

#include <net/if.h>
#include <netax25/ax25.h>
#include <netrose/rose.h>

#include <netax25/daemon.h>
#include <netax25/axlib.h>
#include <netax25/ttyutils.h>


static int setifcall(int fd, char *name)
{
    char call[7];

    if (ax25_aton_entry(name, call) == -1)
        return FALSE;

    if (ioctl(fd, SIOCSIFHWADDR, call) != 0) {
        close(fd);
        perror("SIOCSIFHWADDR");
        return FALSE;
    }

    return TRUE;
}


static int startiface(char *dev, int mtu, int allow_broadcast)
{
    struct ifreq ifr;
    int fd;

    if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket");
        return FALSE;
    }

    strcpy(ifr.ifr_name, dev);

    ifr.ifr_mtu = mtu;

    if (ioctl(fd, SIOCSIFMTU, &ifr) < 0) {
        perror("SIOCSIFMTU");
        return FALSE;
    }

    if (ioctl(fd, SIOCGIFFLAGS, &ifr) < 0) {
        perror("SIOCGIFFLAGS");
        return FALSE;
    }

    ifr.ifr_flags &= IFF_NOARP;
    ifr.ifr_flags |= IFF_UP;
    ifr.ifr_flags |= IFF_RUNNING;
    if (allow_broadcast)
        ifr.ifr_flags |= IFF_BROADCAST; /* samba broadcasts are a pain.. */
    else
        ifr.ifr_flags &= ~(IFF_BROADCAST); /* samba broadcasts are a pain.. */

    if (ioctl(fd, SIOCSIFFLAGS, &ifr) < 0) {
        perror("SIOCSIFFLAGS");
        return FALSE;
    }

    close(fd);

    return TRUE;
}

int32_t kissattach(
        char *callsign,
        int32_t speed,
        int32_t mtu,
        char *kttyname,
        int32_t allow_broadcast)
{
    int  fd;
    int  disc = N_AX25;
    char dev[64];

    if ((fd = open(kttyname, O_RDONLY | O_NONBLOCK)) == -1) {
        perror("open");
        return 0;
    }

    if (speed != 0 && !tty_speed(fd, speed))
        return 0;

    if (ioctl(fd, TIOCSETD, &disc) == -1) {
        //Error setting line discipline
        perror("TIOCSETD");
        fprintf(stderr, "Are you sure you have enabled %s support in the kernel\n",
                disc == N_AX25 ? "MKISS" : "6PACK");
        fprintf(stderr, "or, if you made it a module, that the module is loaded?\n");
        return 0;
    }

    if (ioctl(fd, SIOCGIFNAME, dev) == -1) {
        perror("SIOCGIFNAME");
        return 0;
    }

    if (!setifcall(fd, callsign))
        return 0;

    /* Now set the encapsulation */
    int v = 4;
    if (ioctl(fd, SIOCSIFENCAP, &v) == -1) {
        perror("SIOCSIFENCAP");
        return 0;
    }

    /* ax25 ifaces should not really need to have an IP address assigned to */
    if (!startiface(dev, mtu, allow_broadcast))
        return 0;

    return 1;
}