/*
 * QEMU System Emulator
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "net/tap.h"

#include <sys/stat.h>
#include <sys/ethernet.h>
#include <sys/sockio.h>
#include <netinet/arp.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h> // must come after ip.h
#include <netinet/udp.h>
#include <netinet/tcp.h>
#include <net/if.h>
#include <syslog.h>
#include <stropts.h>

ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
{
    struct strbuf sbuf;
    int f = 0;

    sbuf.maxlen = maxlen;
    sbuf.buf = (char *)buf;

    return getmsg(tapfd, NULL, &sbuf, &f) >= 0 ? sbuf.len : -1;
}

#define TUNNEWPPA       (('T'<<16) | 0x0001)
/*
 * Allocate TAP device, returns opened fd.
 * Stores dev name in the first arg(must be large enough).
 */
static int tap_alloc(char *dev, size_t dev_size)
{
    int tap_fd, if_fd, ppa = -1;
    static int ip_fd = 0;
    char *ptr;

    static int arp_fd = 0;
    int ip_muxid, arp_muxid;
    struct strioctl  strioc_if, strioc_ppa;
    int link_type = I_PLINK;;
    struct lifreq ifr;
    char actual_name[32] = "";

    memset(&ifr, 0x0, sizeof(ifr));

    if( *dev ){
       ptr = dev;
       while( *ptr && !qemu_isdigit((int)*ptr) ) ptr++;
       ppa = atoi(ptr);
    }

    /* Check if IP device was opened */
    if( ip_fd )
       close(ip_fd);

    TFR(ip_fd = open("/dev/udp", O_RDWR, 0));
    if (ip_fd < 0) {
       syslog(LOG_ERR, "Can't open /dev/ip (actually /dev/udp)");
       return -1;
    }

    TFR(tap_fd = open("/dev/tap", O_RDWR, 0));
    if (tap_fd < 0) {
       syslog(LOG_ERR, "Can't open /dev/tap");
       return -1;
    }

    /* Assign a new PPA and get its unit number. */
    strioc_ppa.ic_cmd = TUNNEWPPA;
    strioc_ppa.ic_timout = 0;
    strioc_ppa.ic_len = sizeof(ppa);
    strioc_ppa.ic_dp = (char *)&ppa;
    if ((ppa = ioctl (tap_fd, I_STR, &strioc_ppa)) < 0)
       syslog (LOG_ERR, "Can't assign new interface");

    TFR(if_fd = open("/dev/tap", O_RDWR, 0));
    if (if_fd < 0) {
       syslog(LOG_ERR, "Can't open /dev/tap (2)");
       return -1;
    }
    if(ioctl(if_fd, I_PUSH, "ip") < 0){
       syslog(LOG_ERR, "Can't push IP module");
       return -1;
    }

    if (ioctl(if_fd, SIOCGLIFFLAGS, &ifr) < 0)
	syslog(LOG_ERR, "Can't get flags\n");

    snprintf (actual_name, 32, "tap%d", ppa);
    pstrcpy(ifr.lifr_name, sizeof(ifr.lifr_name), actual_name);

    ifr.lifr_ppa = ppa;
    /* Assign ppa according to the unit number returned by tun device */

    if (ioctl (if_fd, SIOCSLIFNAME, &ifr) < 0)
        syslog (LOG_ERR, "Can't set PPA %d", ppa);
    if (ioctl(if_fd, SIOCGLIFFLAGS, &ifr) <0)
        syslog (LOG_ERR, "Can't get flags\n");
    /* Push arp module to if_fd */
    if (ioctl (if_fd, I_PUSH, "arp") < 0)
        syslog (LOG_ERR, "Can't push ARP module (2)");

    /* Push arp module to ip_fd */
    if (ioctl (ip_fd, I_POP, NULL) < 0)
        syslog (LOG_ERR, "I_POP failed\n");
    if (ioctl (ip_fd, I_PUSH, "arp") < 0)
        syslog (LOG_ERR, "Can't push ARP module (3)\n");
    /* Open arp_fd */
    TFR(arp_fd = open ("/dev/tap", O_RDWR, 0));
    if (arp_fd < 0)
       syslog (LOG_ERR, "Can't open %s\n", "/dev/tap");

    /* Set ifname to arp */
    strioc_if.ic_cmd = SIOCSLIFNAME;
    strioc_if.ic_timout = 0;
    strioc_if.ic_len = sizeof(ifr);
    strioc_if.ic_dp = (char *)&ifr;
    if (ioctl(arp_fd, I_STR, &strioc_if) < 0){
        syslog (LOG_ERR, "Can't set ifname to arp\n");
    }

    if((ip_muxid = ioctl(ip_fd, I_LINK, if_fd)) < 0){
       syslog(LOG_ERR, "Can't link TAP device to IP");
       return -1;
    }

    if ((arp_muxid = ioctl (ip_fd, link_type, arp_fd)) < 0)
        syslog (LOG_ERR, "Can't link TAP device to ARP");

    close (if_fd);

    memset(&ifr, 0x0, sizeof(ifr));
    pstrcpy(ifr.lifr_name, sizeof(ifr.lifr_name), actual_name);
    ifr.lifr_ip_muxid  = ip_muxid;
    ifr.lifr_arp_muxid = arp_muxid;

    if (ioctl (ip_fd, SIOCSLIFMUXID, &ifr) < 0)
    {
      ioctl (ip_fd, I_PUNLINK , arp_muxid);
      ioctl (ip_fd, I_PUNLINK, ip_muxid);
      syslog (LOG_ERR, "Can't set multiplexor id");
    }

    snprintf(dev, dev_size, "tap%d", ppa);
    return tap_fd;
}

int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)
{
    char  dev[10]="";
    int fd;
    if( (fd = tap_alloc(dev, sizeof(dev))) < 0 ){
       fprintf(stderr, "Cannot allocate TAP device\n");
       return -1;
    }
    pstrcpy(ifname, ifname_size, dev);
    fcntl(fd, F_SETFL, O_NONBLOCK);
    return fd;
}

int tap_set_sndbuf(int fd, QemuOpts *opts)
{
    return 0;
}

int tap_probe_vnet_hdr(int fd)
{
    return 0;
}

int tap_probe_has_ufo(int fd)
{
    return 0;
}

void tap_fd_set_offload(int fd, int csum, int tso4,
                        int tso6, int ecn, int ufo)
{
}