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#include "EXTERN.h"
#include "perl.h"
#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/route.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#define ROUNDUP(a) \
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
#define MAX_IFS 32
static int
dev_name(u_int32_t ipaddr, u_char *name)
{
struct ifreq *ifr, *ifend;
#ifdef HAVE_SOCKADDR_SA_LEN
register int n;
#endif
u_long ina,mask,pdst;
struct sockaddr_dl *dla;
struct ifreq ifreq;
struct ifconf ifc;
struct ifreq ifs[MAX_IFS];
int s,len,ppp;
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) {
ppp = 0;
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))
goto nextif;
if (ifreq.ifr_flags & IFF_POINTOPOINT) ppp = 1;
if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0)
continue;
mask = ((struct sockaddr_in *)
&ifreq.ifr_addr)->sin_addr.s_addr;
if ((ipaddr & mask) ^ (ina & mask)) {
if(!ppp) {
goto nextif;
}
else {
if (ioctl(s, SIOCGIFDSTADDR, &ifreq) < 0)
continue;
pdst = ((struct sockaddr_in *)
&ifreq.ifr_addr)->sin_addr.s_addr;
if (pdst ^ ipaddr) goto nextif;
}
}
break;
}
nextif:
#ifdef HAVE_SOCKADDR_SA_LEN
n = ifr->ifr_addr.sa_len + sizeof(ifr->ifr_name);
if (n < sizeof(*ifr))
{
ifr = ifr + 1;
}
else
{
ifr = (struct ifreq *)((char *)ifr + n);
}
#else
ifr = ifr + 1;
#endif
}
if (ifr >= ifend) {
close(s);
return 0;
}
close(s);
len = strlen(ifr->ifr_name);
memcpy(name,ifr->ifr_name,len);
return len;
}
int
ip_rt_dev(u_int32_t addr,u_char *name)
{
size_t needed;
int mib[6], rlen, seqno;
char *buf, *next, *lim,i;
register struct rt_msghdr *rtm;
struct sockaddr *sa ;
struct sockaddr_in *sin;
u_int32_t devip = 0,dest,mask,gate,local;
char *cp;
local = htonl(0x7f000001);
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = 0;
mib[4] = NET_RT_DUMP;
mib[5] = 0;
if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0){
croak("route-sysctl-estimate");
}
if ((buf = malloc(needed)) == NULL){
croak("malloc");
}
if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0){
croak("route-sysctl-get");
}
lim = buf + needed;
for (next = buf; next < lim; next += rtm->rtm_msglen) {
rtm = (struct rt_msghdr *)next;
sa = (struct sockaddr *)(rtm + 1);
cp = (char*)sa;
if (sa->sa_family != AF_INET)
continue;
dest = mask = gate = 0;
for (i = 1; i; i <<= 1)
if (i & rtm->rtm_addrs) {
sa = (struct sockaddr *)cp;
switch (i) {
case RTA_DST:
sin = (struct sockaddr_in*)sa;
dest = sin->sin_addr.s_addr;
break;
case RTA_GATEWAY:
if(rtm->rtm_flags & RTF_GATEWAY){
sin = (struct sockaddr_in*)sa;
gate = sin->sin_addr.s_addr;
}
break;
case RTA_NETMASK:
sin = (struct sockaddr_in*)sa;
mask = sin->sin_addr.s_addr;
break;
}
ADVANCE(cp, sa);
}
if(!(rtm->rtm_flags & RTF_LLINFO) && (rtm->rtm_flags & RTF_HOST))
mask = 0xffffffff;
if(!mask && dest && (dest != local)) continue;
if(!dest) mask = 0;
if(dest == local) {
dest = htonl(0x7f000000); mask = htonl(0xff000000);
}
if(!((mask & addr) ^ dest)){
switch (gate) {
case 0:
devip = addr;
break;
default:
devip = gate;
}
}
}
free(buf);
return dev_name(devip,name);
}
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