1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226
|
/*
* proxyarp.c - set up or clear proxyarp routing on a device.
*
* This code was taken from pppd-2.2.0e, with some revisions copied
* from pppd-2.2.0f.
*
* Copyright (c) 1989 Carnegie Mellon University.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by Carnegie Mellon University. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include "diald.h"
/* This is in netdevice.h. However, this compile will fail miserably if
you attempt to include netdevice.h because it has so many references
to __memcpy functions which it should not attempt to do. So, since I
really don't use it, but it must be defined, define it now. */
#ifndef MAX_ADDR_LEN
#define MAX_ADDR_LEN 7
#endif
#include <net/if.h>
#include <net/if_arp.h>
/* #include <net/route.h> */
extern int sockfd; /* socket for doing interface ioctls */
#define MAX_IFS 100
#define FLAGS_GOOD (IFF_UP | IFF_BROADCAST)
#define FLAGS_MASK (IFF_UP | IFF_BROADCAST | \
IFF_POINTOPOINT | IFF_LOOPBACK | IFF_NOARP)
/*
* SET_SA_FAMILY - set the sa_family field of a struct sockaddr,
* if it exists.
*/
#define SET_SA_FAMILY(addr, family) \
memset ((char *) &(addr), '\0', sizeof(addr)); \
addr.sa_family = (family);
/*
* Make a string representation of a network IP address.
*/
char * ip_ntoa(unsigned int ipaddr)
{
static char b[64];
ipaddr = ntohl(ipaddr);
sprintf(b, "%d.%d.%d.%d",
(u_char)(ipaddr >> 24),
(u_char)(ipaddr >> 16),
(u_char)(ipaddr >> 8),
(u_char)(ipaddr));
return b;
}
/*
* get_ether_addr - get the hardware address of an interface on the
* the same subnet as ipaddr.
*/
static int get_ether_addr (unsigned int ipaddr, struct sockaddr *hwaddr)
{
struct ifreq *ifr, *ifend;
unsigned int ina, mask;
struct ifreq ifreq;
struct ifconf ifc;
struct ifreq ifs[MAX_IFS];
ifc.ifc_len = sizeof(ifs);
ifc.ifc_req = ifs;
if (ioctl(sockfd, SIOCGIFCONF, &ifc) < 0)
{
syslog(LOG_ERR, "ioctl(SIOCGIFCONF): %m");
return 0;
}
if (debug&DEBUG_PROXYARP)
syslog(LOG_INFO, "proxy arp: scanning %d interfaces for IP %s",
ifc.ifc_len / sizeof(struct ifreq), ip_ntoa(ipaddr));
/*
* Scan through looking for an interface with an Internet
* address on the same subnet as `ipaddr'.
*/
ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
for (ifr = ifc.ifc_req; ifr < ifend; ifr++)
{
if (ifr->ifr_addr.sa_family == AF_INET)
{
ina = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr;
strncpy(ifreq.ifr_name, ifr->ifr_name, sizeof(ifreq.ifr_name));
if (debug&DEBUG_PROXYARP)
syslog(LOG_INFO, "proxy arp: examining interface %s",
ifreq.ifr_name);
/*
* Check that the interface is up, and not point-to-point
* nor loopback.
*/
if (ioctl(sockfd, SIOCGIFFLAGS, &ifreq) < 0)
{
continue;
}
if (((ifreq.ifr_flags ^ FLAGS_GOOD) & FLAGS_MASK) != 0)
{
continue;
}
/*
* Get its netmask and check that it's on the right subnet.
*/
if (ioctl(sockfd, SIOCGIFNETMASK, &ifreq) < 0)
{
continue;
}
mask = ((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr.s_addr;
if (debug&DEBUG_PROXYARP)
syslog(LOG_INFO, "proxy arp: interface addr %s mask %lx",
ip_ntoa(ina), ntohl(mask));
if (((ipaddr ^ ina) & mask) != 0)
{
continue;
}
break;
}
}
if (ifr >= ifend)
{
return 0;
}
syslog(LOG_INFO, "found interface %s for proxy arp", ifreq.ifr_name);
/*
* Now get the hardware address.
*/
memset (&ifreq.ifr_hwaddr, 0, sizeof (struct sockaddr));
if (ioctl (sockfd, SIOCGIFHWADDR, &ifreq) < 0)
{
syslog(LOG_ERR, "SIOCGIFHWADDR(%s): %m", ifreq.ifr_name);
return 0;
}
memcpy (hwaddr,
&ifreq.ifr_hwaddr,
sizeof (struct sockaddr));
if (debug&DEBUG_PROXYARP)
syslog(LOG_INFO,
"proxy arp: found hwaddr %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x",
(int) ((unsigned char *) &hwaddr->sa_data)[0],
(int) ((unsigned char *) &hwaddr->sa_data)[1],
(int) ((unsigned char *) &hwaddr->sa_data)[2],
(int) ((unsigned char *) &hwaddr->sa_data)[3],
(int) ((unsigned char *) &hwaddr->sa_data)[4],
(int) ((unsigned char *) &hwaddr->sa_data)[5],
(int) ((unsigned char *) &hwaddr->sa_data)[6],
(int) ((unsigned char *) &hwaddr->sa_data)[7]);
return 1;
}
/*
* set_proxyarp - Make a proxy ARP entry for the peer.
*/
int set_proxyarp (unsigned int his_adr)
{
struct arpreq arpreq;
memset (&arpreq, '\0', sizeof(arpreq));
/*
* Get the hardware address of an interface on the same subnet
* as our local address.
*/
if (!get_ether_addr(his_adr, &arpreq.arp_ha)) {
syslog(LOG_ERR, "Cannot determine ethernet address for proxy ARP");
return 0;
}
SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
((struct sockaddr_in *) &arpreq.arp_pa)->sin_addr.s_addr = his_adr;
arpreq.arp_flags = ATF_PERM | ATF_PUBL;
if (ioctl(sockfd, SIOCSARP, (caddr_t)&arpreq) < 0) {
syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
return 0;
}
return 1;
}
/*
* clear_proxyarp - Delete the proxy ARP entry for the peer.
*/
int clear_proxyarp (unsigned int his_adr)
{
struct arpreq arpreq;
memset (&arpreq, '\0', sizeof(arpreq));
SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
arpreq.arp_flags = ATF_PERM | ATF_PUBL;
((struct sockaddr_in *) &arpreq.arp_pa)->sin_addr.s_addr = his_adr;
if (ioctl(sockfd, SIOCDARP, (caddr_t)&arpreq) < 0) {
syslog(LOG_WARNING, "ioctl(SIOCDARP): %m");
return 0;
}
return 1;
}
|