#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#ifdef  _BPF_
#include <sys/param.h>
#endif

#include <sys/types.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <sys/uio.h>

#ifdef _LINUX_

#include <stdio.h>

#ifdef  _GLIBC_

#include <net/if_packet.h>
#include <netinet/if_ether.h>
#include <net/if.h>

#else 

#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/if.h>

#endif /*_GLIBC_*/

#else 

#define MAX_IFS		32

#include <sys/time.h>
#include <net/bpf.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <sys/sysctl.h>
#include <net/route.h>
#include <netinet/if_ether.h>
#include <unistd.h>
#include "ip.h"

#ifdef _BSDRAW_

unsigned short in_cksum (unsigned short*,int);

#endif
#endif /*_LINUX_*/

#ifdef _BPF_

static int
get_ether_addr(u_long ipaddr, u_char *hwaddr)
{
	struct ifreq *ifr, *ifend, *ifp;
	u_long ina, mask;
	struct sockaddr_dl *dla;
	struct ifreq ifreq;
	struct ifconf ifc;
	struct ifreq ifs[MAX_IFS];
	int s;

	s = socket(AF_INET, SOCK_DGRAM, 0);
	if (s < 0)
		perror("socket");

	ifc.ifc_len = sizeof(ifs);
	ifc.ifc_req = ifs;
	if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
		close(s);
		return 0;
	}
	ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
	for (ifr = ifc.ifc_req; ifr < ifend; ) {
		if (ifr->ifr_addr.sa_family == AF_INET) {
			ina = ((struct sockaddr_in *) 
				&ifr->ifr_addr)->sin_addr.s_addr;
			strncpy(ifreq.ifr_name, ifr->ifr_name, 
				sizeof(ifreq.ifr_name));
			if (ioctl(s, SIOCGIFFLAGS, &ifreq) < 0)
				continue;
			if ((ifreq.ifr_flags &
			     (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
					IFF_LOOPBACK|IFF_NOARP))
			     != (IFF_UP|IFF_BROADCAST))
				goto nextif;
			if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0)
				continue;
			mask = ((struct sockaddr_in *)
				&ifreq.ifr_addr)->sin_addr.s_addr;
			if ((ipaddr & mask) != (ina & mask))
				goto nextif;
			break;
		}
nextif:
		ifr = (struct ifreq *) 
		    ((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len);
	}

	if (ifr >= ifend) {
		close(s);
		return 0;
	}
	ifp = ifr;
	for (ifr = ifc.ifc_req; ifr < ifend; ) {
		if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0
		    && ifr->ifr_addr.sa_family == AF_LINK) {
		 	dla = (struct sockaddr_dl *) &ifr->ifr_addr;
			memcpy(hwaddr,LLADDR(dla),dla->sdl_alen);
			close (s);
			return dla->sdl_alen;
		}
		ifr = (struct ifreq *) 
			((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len);
	}
	return 0;
}

#endif /*_BPF_*/
											
void send_eth_packet(int fd,char* eth_device,u_char *pkt,int len,int flag)
{
        int retval;

#ifndef _BPF_

        struct msghdr msg;
	struct sockaddr_pkt spkt;
	struct iovec iov;
	strcpy(spkt.spkt_device, eth_device);
	spkt.spkt_protocol = htons(ETH_P_IP);
	memset(&msg, 0, sizeof(msg));
	msg.msg_name = &spkt;
	msg.msg_namelen = sizeof(spkt);
	msg.msg_iovlen = 1;
	msg.msg_iov = &iov;
	iov.iov_base = pkt;
	iov.iov_len = len;

	retval = sendmsg(fd, &msg, 0);
#else	

#ifdef _BSDRAW_
if(flag){
((struct iphdr *)(pkt + 14))->tot_len = htons(((struct iphdr *)(pkt + 14))->tot_len);        
((struct iphdr *)(pkt + 14))->frag_off = htons(((struct iphdr *)(pkt + 14))->frag_off);        
((struct iphdr *)(pkt + 14))->check = 0;        
((struct iphdr *)(pkt + 14))->check = in_cksum((unsigned short*)(pkt + 14),
                                          4*((struct iphdr *)(pkt + 14))->ihl);                
        }
#endif
        retval = write(fd,pkt,len);
#endif
	if (retval < 0) {
	       croak("send_eth_packet");
	}       
}


int mac_disc(unsigned int addr,unsigned char * eth_mac){

#ifndef _BPF_

struct arpreq
  {
    struct sockaddr arp_pa;		
    struct sockaddr arp_ha;		
    int arp_flags;			
    struct sockaddr arp_netmask;
    char arp_dev[16];
  } req;
int fd;
fd = socket(AF_INET,SOCK_DGRAM,0);
memset((char*)&req,0,sizeof(req));
req.arp_pa.sa_family = AF_INET;
*(unsigned int*)(req.arp_pa.sa_data+2) = htonl(addr);
if(ioctl(fd,SIOCGARP,&req) < 0){
close(fd);
return 0;
}
memcpy(eth_mac, req.arp_ha.sa_data, ETH_ALEN);
close(fd);
return 1;

#else
        
	int mib[6],found;
	size_t needed;
	char *lim, *buf, *next;
	struct rt_msghdr *rtm;
	struct sockaddr_inarp *sin;
	struct sockaddr_dl *sdl;
	extern int h_errno;
        mib[0] = CTL_NET;
	mib[1] = PF_ROUTE;
	mib[2] = 0;
	mib[3] = AF_INET;
	mib[4] = NET_RT_FLAGS;
	mib[5] = RTF_LLINFO;
	found = 0;
	if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
		perror("route-sysctl-estimate");
	if ((buf = (char*)malloc(needed)) == NULL)
		perror("malloc");
	if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
		perror("actual retrieval of routing table");
	lim = buf + needed;
	for (next = buf; next < lim; next += rtm->rtm_msglen) {
		rtm = (struct rt_msghdr *)next;
		sin = (struct sockaddr_inarp *)(rtm + 1);
		sdl = (struct sockaddr_dl *)(sin + 1);
			if (addr != ntohl(sin->sin_addr.s_addr))
				continue;
			found = 1;
		}
	if(!found){
	return 0;
	} else {
	       memcpy(eth_mac,LLADDR(sdl),sdl->sdl_alen);
	return 1;    
	}
#endif
}


int
tap(char *dev,unsigned int *my_eth_ip,unsigned char *my_eth_mac)
{
	
	int fd,v,s;				
	struct ifreq ifr;   
        (void)strcpy(ifr.ifr_name, dev);
#ifndef _BPF_
	
        if ((fd = socket(AF_INET, SOCK_PACKET, htons(ETH_P_ALL))) < 0) {
            croak("(tap) SOCK_PACKET allocation problems [fatal]");
	}
#else
        if ((fd = bpf_open()) < 0) croak("(tap) fd < 0");
        v = 32768;      
        (void) ioctl(fd, BIOCSBLEN, (caddr_t)&v);
        if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) {
            croak("(tap) BIOCSETIF problems [fatal]");
        }
        s = socket(AF_INET,SOCK_DGRAM,0);
	if (ioctl(s, SIOCGIFADDR, &ifr) < 0) {
#endif													    	

#ifndef _BPF_
        if (ioctl(fd, SIOCGIFADDR, &ifr) < 0) {

        close(fd);
	    croak("(tap) Can't get interface IP address");
#else
        close(fd);
        close(s);
#endif
	    croak("(tap) Can't get interface IP address");
	}
	
*my_eth_ip = ntohl(((struct sockaddr_in*)&ifr.ifr_addr)->sin_addr.s_addr);

#ifndef _BPF_

if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
	close(fd);
	croak("(tap) Can't get interface HW address");
	}
	memcpy(my_eth_mac, ifr.ifr_hwaddr.sa_data,ETH_ALEN);
#else
        close(s);
if (!get_ether_addr(((struct sockaddr_in*)&ifr.ifr_addr)->sin_addr.s_addr,
     my_eth_mac)) {
     croak("(tap) Can't get interface HW address");
     }
#endif
return fd;
}