contrib/ipfilter/ipsend/arp.c

   1 /*
   2  * arp.c (C) 1995-1998 Darren Reed
   3  *
   4  * See the IPFILTER.LICENCE file for details on licencing.
   5  */
   6 #if defined(__sgi) && (IRIX > 602)
   7 # include <sys/ptimers.h>
   8 #endif
   9 #include <stdio.h>
  10 #include <errno.h>
  11 #include <sys/types.h>
  12 #include <sys/socket.h>
  13 #if !defined(ultrix) && !defined(hpux)
  14 #include <sys/sockio.h>
  15 #endif
  16 #include <sys/ioctl.h>
  17 #include <netdb.h>
  18 #include <netinet/in.h>
  19 #include <net/if.h>
  20 #include <netinet/if_ether.h>
  21 #ifndef ultrix
  22 #include <net/if_arp.h>
  23 #endif
  24 #include <netinet/in.h>
  25 #include <netinet/ip_var.h>
  26 #include <netinet/tcp.h>
  27 #include "ipsend.h"
  28 #include "iplang/iplang.h"
  29
  30 #if !defined(lint)
  31 static const char sccsid[] = "@(#)arp.c 1.4 1/11/96 (C)1995 Darren Reed";
  32 static const char rcsid[] = "@(#)$Id: arp.c,v 2.1.4.4 2002/12/06 11:40:35 darrenr Exp $";
  33 #endif
  34
  35
  36 /*
  37  * lookup host and return
  38  * its IP address in address
  39  * (4 bytes)
  40  */
  41 int     resolve(host, address)
  42 char    *host, *address;
  43 {
  44         struct  hostent *hp;
  45         u_long  add;
  46
  47         add = inet_addr(host);
  48         if (add == -1)
  49             {
  50                 if (!(hp = gethostbyname(host)))
  51                     {
  52                         fprintf(stderr, "unknown host: %s\n", host);
  53                         return -1;
  54                     }
  55                 bcopy((char *)hp->h_addr, (char *)address, 4);
  56                 return 0;
  57         }
  58         bcopy((char*)&add, address, 4);
  59         return 0;
  60 }
  61
  62 /*
  63  * ARP for the MAC address corresponding
  64  * to the IP address.  This taken from
  65  * some BSD program, I cant remember which.
  66  */
  67 int     arp(ip, ether)
  68 char    *ip;
  69 char    *ether;
  70 {
  71         static  int     sfd = -1;
  72         static  char    ethersave[6], ipsave[4];
  73         struct  arpreq  ar;
  74         struct  sockaddr_in     *sin, san;
  75         struct  hostent *hp;
  76         int     fd;
  77
  78 #ifdef  IPSEND
  79         if (arp_getipv4(ip, ether) == 0)
  80                 return 0;
  81 #endif
  82         if (!bcmp(ipsave, ip, 4)) {
  83                 bcopy(ethersave, ether, 6);
  84                 return 0;
  85         }
  86         fd = -1;
  87         bzero((char *)&ar, sizeof(ar));
  88         sin = (struct sockaddr_in *)&ar.arp_pa;
  89         sin->sin_family = AF_INET;
  90         bcopy(ip, (char *)&sin->sin_addr.s_addr, 4);
  91 #ifndef hpux
  92         if ((hp = gethostbyaddr(ip, 4, AF_INET)))
  93                 if (!(ether_hostton(hp->h_name, ether)))
  94                         goto savearp;
  95 #endif
  96
  97         if (sfd == -1)
  98                 if ((sfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
  99                     {
 100                         perror("arp: socket");
 101                         return -1;
 102                     }
 103 tryagain:
 104         if (ioctl(sfd, SIOCGARP, (caddr_t)&ar) == -1)
 105             {
 106                 if (fd == -1)
 107                     {
 108                         bzero((char *)&san, sizeof(san));
 109                         san.sin_family = AF_INET;
 110                         san.sin_port = htons(1);
 111                         bcopy(ip, &san.sin_addr.s_addr, 4);
 112                         fd = socket(AF_INET, SOCK_DGRAM, 0);
 113                         (void) sendto(fd, ip, 4, 0,
 114                                       (struct sockaddr *)&san, sizeof(san));
 115                         sleep(1);
 116                         (void) close(fd);
 117                         goto tryagain;
 118                     }
 119                 fprintf(stderr, "(%s):", inet_ntoa(sin->sin_addr));
 120                 if (errno != ENXIO)
 121                         perror("SIOCGARP");
 122                 return -1;
 123             }
 124
 125         bcopy(ar.arp_ha.sa_data, ether, 6);
 126 savearp:
 127         bcopy(ether, ethersave, 6);
 128         bcopy(ip, ipsave, 4);
 129         return 0;
 130 }