1/*	$FreeBSD: stable/11/contrib/ipfilter/ipsend/arp.c 363769 2020-08-02 04:25:36Z cy $	*/
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[] = "@(#)$Id$";
11#endif
12#include <sys/types.h>
13#include <sys/socket.h>
14# include <sys/sockio.h>
15#include <sys/ioctl.h>
16#include <netinet/in_systm.h>
17#include <netinet/in.h>
18#include <net/if.h>
19#include <netinet/if_ether.h>
20# include <net/if_arp.h>
21#include <netinet/in.h>
22#include <netinet/ip.h>
23#include <netinet/ip_var.h>
24#include <netinet/tcp.h>
25#include <stdio.h>
26#include <errno.h>
27#include <netdb.h>
28#include "ipsend.h"
29#include "iplang/iplang.h"
30
31
32/*
33 * lookup host and return
34 * its IP address in address
35 * (4 bytes)
36 */
37int	resolve(host, address)
38	char	*host, *address;
39{
40        struct	hostent	*hp;
41        u_long	add;
42
43	add = inet_addr(host);
44	if (add == -1)
45	    {
46		if (!(hp = gethostbyname(host)))
47		    {
48			fprintf(stderr, "unknown host: %s\n", host);
49			return -1;
50		    }
51		bcopy((char *)hp->h_addr, (char *)address, 4);
52		return 0;
53	}
54	bcopy((char*)&add, address, 4);
55	return 0;
56}
57
58/*
59 * ARP for the MAC address corresponding
60 * to the IP address.  This taken from
61 * some BSD program, I cant remember which.
62 */
63int	arp(ip, ether)
64	char	*ip;
65	char	*ether;
66{
67	static	int	sfd = -1;
68	static	char	ethersave[6], ipsave[4];
69	struct	arpreq	ar;
70	struct	sockaddr_in	*sin, san;
71	struct	hostent	*hp;
72	int	fd;
73
74#ifdef	IPSEND
75	if (arp_getipv4(ip, ether) == 0)
76		return 0;
77#endif
78	if (!bcmp(ipsave, ip, 4)) {
79		bcopy(ethersave, ether, 6);
80		return 0;
81	}
82	fd = -1;
83	bzero((char *)&ar, sizeof(ar));
84	sin = (struct sockaddr_in *)&ar.arp_pa;
85	sin->sin_family = AF_INET;
86	bcopy(ip, (char *)&sin->sin_addr.s_addr, 4);
87	if ((hp = gethostbyaddr(ip, 4, AF_INET)))
88# if SOLARIS && (SOLARIS2 >= 10)
89		if (!(ether_hostton(hp->h_name, (struct ether_addr *)ether)))
90# else
91		if (!(ether_hostton(hp->h_name, ether)))
92# endif
93			goto savearp;
94
95	if (sfd == -1)
96		if ((sfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
97		    {
98			perror("arp: socket");
99			return -1;
100		    }
101tryagain:
102	if (ioctl(sfd, SIOCGARP, (caddr_t)&ar) == -1)
103	    {
104		if (fd == -1)
105		    {
106			bzero((char *)&san, sizeof(san));
107			san.sin_family = AF_INET;
108			san.sin_port = htons(1);
109			bcopy(ip, &san.sin_addr.s_addr, 4);
110			fd = socket(AF_INET, SOCK_DGRAM, 0);
111			(void) sendto(fd, ip, 4, 0,
112				      (struct sockaddr *)&san, sizeof(san));
113			sleep(1);
114			(void) close(fd);
115			goto tryagain;
116		    }
117		fprintf(stderr, "(%s):", inet_ntoa(sin->sin_addr));
118		if (errno != ENXIO)
119			perror("SIOCGARP");
120		return -1;
121	    }
122
123	if ((ar.arp_ha.sa_data[0] == 0) && (ar.arp_ha.sa_data[1] == 0) &&
124	    (ar.arp_ha.sa_data[2] == 0) && (ar.arp_ha.sa_data[3] == 0) &&
125	    (ar.arp_ha.sa_data[4] == 0) && (ar.arp_ha.sa_data[5] == 0)) {
126		fprintf(stderr, "(%s):", inet_ntoa(sin->sin_addr));
127		return -1;
128	}
129
130	bcopy(ar.arp_ha.sa_data, ether, 6);
131savearp:
132	bcopy(ether, ethersave, 6);
133	bcopy(ip, ipsave, 4);
134	return 0;
135}
136