arp.c revision 170268 
1/*	$FreeBSD: head/contrib/ipfilter/ipsend/arp.c 170268 2007-06-04 02:54:36Z darrenr $	*/
2
3/*
4 * arp.c (C) 1995-1998 Darren Reed
5 *
6 * See the IPFILTER.LICENCE file for details on licencing.
7 */
8#if !defined(lint)
9static const char sccsid[] = "@(#)arp.c	1.4 1/11/96 (C)1995 Darren Reed";
10static const char rcsid[] = "@(#)$Id: arp.c,v 2.8.2.2 2007/02/17 12:41:50 darrenr Exp $";
11#endif
12#include <sys/types.h>
13#include <sys/socket.h>
14#if !defined(ultrix) && !defined(hpux) && !defined(__hpux) && !defined(__osf__) && !defined(_AIX51)
15# include <sys/sockio.h>
16#endif
17#include <sys/ioctl.h>
18#include <netinet/in_systm.h>
19#include <netinet/in.h>
20#ifdef __osf__
21# include "radix_ipf_local.h"
22#endif
23#include <net/if.h>
24#include <netinet/if_ether.h>
25#ifndef	ultrix
26# include <net/if_arp.h>
27#endif
28#include <netinet/in.h>
29#include <netinet/ip.h>
30#include <netinet/ip_var.h>
31#include <netinet/tcp.h>
32#include <stdio.h>
33#include <errno.h>
34#include <netdb.h>
35#include "ipsend.h"
36#include "iplang/iplang.h"
37
38
39/*
40 * lookup host and return
41 * its IP address in address
42 * (4 bytes)
43 */
44int	resolve(host, address)
45char	*host, *address;
46{
47        struct	hostent	*hp;
48        u_long	add;
49
50	add = inet_addr(host);
51	if (add == -1)
52	    {
53		if (!(hp = gethostbyname(host)))
54		    {
55			fprintf(stderr, "unknown host: %s\n", host);
56			return -1;
57		    }
58		bcopy((char *)hp->h_addr, (char *)address, 4);
59		return 0;
60	}
61	bcopy((char*)&add, address, 4);
62	return 0;
63}
64
65/*
66 * ARP for the MAC address corresponding
67 * to the IP address.  This taken from
68 * some BSD program, I cant remember which.
69 */
70int	arp(ip, ether)
71char	*ip;
72char	*ether;
73{
74	static	int	sfd = -1;
75	static	char	ethersave[6], ipsave[4];
76	struct	arpreq	ar;
77	struct	sockaddr_in	*sin, san;
78	struct	hostent	*hp;
79	int	fd;
80
81#ifdef	IPSEND
82	if (arp_getipv4(ip, ether) == 0)
83		return 0;
84#endif
85	if (!bcmp(ipsave, ip, 4)) {
86		bcopy(ethersave, ether, 6);
87		return 0;
88	}
89	fd = -1;
90	bzero((char *)&ar, sizeof(ar));
91	sin = (struct sockaddr_in *)&ar.arp_pa;
92	sin->sin_family = AF_INET;
93	bcopy(ip, (char *)&sin->sin_addr.s_addr, 4);
94#ifndef	hpux
95	if ((hp = gethostbyaddr(ip, 4, AF_INET)))
96# if SOLARIS && (SOLARIS2 >= 10)
97		if (!(ether_hostton(hp->h_name, (struct ether_addr *)ether)))
98# else
99		if (!(ether_hostton(hp->h_name, ether)))
100# endif
101			goto savearp;
102#endif
103
104	if (sfd == -1)
105		if ((sfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
106		    {
107			perror("arp: socket");
108			return -1;
109		    }
110tryagain:
111	if (ioctl(sfd, SIOCGARP, (caddr_t)&ar) == -1)
112	    {
113		if (fd == -1)
114		    {
115			bzero((char *)&san, sizeof(san));
116			san.sin_family = AF_INET;
117			san.sin_port = htons(1);
118			bcopy(ip, &san.sin_addr.s_addr, 4);
119			fd = socket(AF_INET, SOCK_DGRAM, 0);
120			(void) sendto(fd, ip, 4, 0,
121				      (struct sockaddr *)&san, sizeof(san));
122			sleep(1);
123			(void) close(fd);
124			goto tryagain;
125		    }
126		fprintf(stderr, "(%s):", inet_ntoa(sin->sin_addr));
127		if (errno != ENXIO)
128			perror("SIOCGARP");
129		return -1;
130	    }
131
132	if ((ar.arp_ha.sa_data[0] == 0) && (ar.arp_ha.sa_data[1] == 0) &&
133	    (ar.arp_ha.sa_data[2] == 0) && (ar.arp_ha.sa_data[3] == 0) &&
134	    (ar.arp_ha.sa_data[4] == 0) && (ar.arp_ha.sa_data[5] == 0)) {
135		fprintf(stderr, "(%s):", inet_ntoa(sin->sin_addr));
136		return -1;
137	}
138
139	bcopy(ar.arp_ha.sa_data, ether, 6);
140savearp:
141	bcopy(ether, ethersave, 6);
142	bcopy(ip, ipsave, 4);
143	return 0;
144}
145