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arp.c
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arp.c
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/*
* arp.c
*
* ARP cache routines.
*
* Copyright (c) 1999 Dug Song <dugsong@monkey.org>
*
* $Id: arp.c,v 1.8 2001/03/15 08:32:58 dugsong Exp $
*/
#include "config.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#ifdef BSD
#include <sys/sysctl.h>
#include <net/if_dl.h>
#include <net/route.h>
#ifdef __FreeBSD__ /* XXX */
#define ether_addr_octet octet
#endif
#else /* !BSD */
#include <sys/ioctl.h>
#ifndef __linux__
#include <sys/sockio.h>
#endif
#endif /* !BSD */
#include <net/if.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "arp.h"
#ifdef BSD
int
arp_cache_lookup(in_addr_t ip, struct ether_addr *ether, const char* linf)
{
int mib[6];
size_t len;
char *buf, *next, *end;
struct rt_msghdr *rtm;
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
mib[0] = CTL_NET;
mib[1] = AF_ROUTE;
mib[2] = 0;
mib[3] = AF_INET;
mib[4] = NET_RT_FLAGS;
mib[5] = RTF_LLINFO;
if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
return (-1);
if ((buf = (char *)malloc(len)) == NULL)
return (-1);
if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
free(buf);
return (-1);
}
end = buf + len;
for (next = buf ; next < end ; next += rtm->rtm_msglen) {
rtm = (struct rt_msghdr *)next;
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin + 1);
if (sin->sin_addr.s_addr == ip && sdl->sdl_alen) {
memcpy(ether->ether_addr_octet, LLADDR(sdl),
ETHER_ADDR_LEN);
free(buf);
return (0);
}
}
free(buf);
return (-1);
}
#else /* !BSD */
#ifndef ETHER_ADDR_LEN /* XXX - Solaris */
#define ETHER_ADDR_LEN 6
#endif
int
arp_cache_lookup(in_addr_t ip, struct ether_addr *ether, const char* lif)
{
int sock;
struct arpreq ar;
struct sockaddr_in *sin;
memset((char *)&ar, 0, sizeof(ar));
#ifdef __linux__
strncpy(ar.arp_dev, lif, strlen(lif));
#endif
sin = (struct sockaddr_in *)&ar.arp_pa;
sin->sin_family = AF_INET;
sin->sin_addr.s_addr = ip;
if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
return (-1);
}
if (ioctl(sock, SIOCGARP, (caddr_t)&ar) == -1) {
close(sock);
return (-1);
}
close(sock);
memcpy(ether->ether_addr_octet, ar.arp_ha.sa_data, ETHER_ADDR_LEN);
/* was the request complete? */
return ((ar.arp_flags & ATF_COM) ? 0 : -1);
}
#endif /* !BSD */