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/*
* arp.c (C) 1995-1998 Darren Reed
*
* Redistribution and use in source and binary forms are permitted
* provided that this notice is preserved and due credit is given
* to the original author and the contributors.
*/
#if !defined(lint)
static const char sccsid[] = "@(#)arp.c 1.4 1/11/96 (C)1995 Darren Reed";
static const char rcsid[] = "@(#)$Id: arp.c,v 2.1 1999/08/04 17:31:03 darrenr Exp $";
#endif
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#if !defined(ultrix) && !defined(hpux)
#include <sys/sockio.h>
#endif
#include <sys/ioctl.h>
#include <netdb.h>
#include <netinet/in.h>
#include <net/if.h>
#include <netinet/if_ether.h>
#ifndef ultrix
#include <net/if_arp.h>
#endif
#include <netinet/in.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include "ipsend.h"
#include "iplang/iplang.h"
/*
* lookup host and return
* its IP address in address
* (4 bytes)
*/
int resolve(host, address)
char *host, *address;
{
struct hostent *hp;
u_long add;
add = inet_addr(host);
if (add == -1)
{
if (!(hp = gethostbyname(host)))
{
fprintf(stderr, "unknown host: %s\n", host);
return -1;
}
bcopy((char *)hp->h_addr, (char *)address, 4);
return 0;
}
bcopy((char*)&add, address, 4);
return 0;
}
/*
* ARP for the MAC address corresponding
* to the IP address. This taken from
* some BSD program, I cant remember which.
*/
int arp(ip, ether)
char *ip;
char *ether;
{
static int sfd = -1;
static char ethersave[6], ipsave[4];
struct arpreq ar;
struct sockaddr_in *sin, san;
struct hostent *hp;
int fd;
#ifdef IPSEND
if (arp_getipv4(ip, ether) == 0)
return 0;
#endif
if (!bcmp(ipsave, ip, 4)) {
bcopy(ethersave, ether, 6);
return 0;
}
fd = -1;
bzero((char *)&ar, sizeof(ar));
sin = (struct sockaddr_in *)&ar.arp_pa;
sin->sin_family = AF_INET;
bcopy(ip, (char *)&sin->sin_addr.s_addr, 4);
#ifndef hpux
if ((hp = gethostbyaddr(ip, 4, AF_INET)))
if (!(ether_hostton(hp->h_name, ether)))
goto savearp;
#endif
if (sfd == -1)
if ((sfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
{
perror("arp: socket");
return -1;
}
tryagain:
if (ioctl(sfd, SIOCGARP, (caddr_t)&ar) == -1)
{
if (fd == -1)
{
bzero((char *)&san, sizeof(san));
san.sin_family = AF_INET;
san.sin_port = htons(1);
bcopy(ip, &san.sin_addr.s_addr, 4);
fd = socket(AF_INET, SOCK_DGRAM, 0);
(void) sendto(fd, ip, 4, 0,
(struct sockaddr *)&san, sizeof(san));
sleep(1);
(void) close(fd);
goto tryagain;
}
fprintf(stderr, "(%s):", inet_ntoa(sin->sin_addr));
if (errno != ENXIO)
perror("SIOCGARP");
return -1;
}
bcopy(ar.arp_ha.sa_data, ether, 6);
savearp:
bcopy(ether, ethersave, 6);
bcopy(ip, ipsave, 4);
return 0;
}
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