OpenBSD-4.6/usr.sbin/ppp/ppp/arp.c
/*
* sys-bsd.c - System-dependent procedures for setting up
* PPP interfaces on bsd-4.4-ish systems (including 386BSD, NetBSD, etc.)
*
* 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.
*
* $OpenBSD: arp.c,v 1.16 2009/07/02 16:08:29 claudio Exp $
*
*/
/*
* TODO:
*/
#include <sys/param.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/route.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <sys/un.h>
#include <errno.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sysctl.h>
#include <termios.h>
#include <unistd.h>
#include "layer.h"
#include "mbuf.h"
#include "log.h"
#include "id.h"
#include "timer.h"
#include "fsm.h"
#include "defs.h"
#include "iplist.h"
#include "throughput.h"
#include "slcompress.h"
#include "lqr.h"
#include "hdlc.h"
#include "ncpaddr.h"
#include "ipcp.h"
#include "ipv6cp.h"
#include "descriptor.h"
#include "lcp.h"
#include "ccp.h"
#include "link.h"
#include "mp.h"
#include "ncp.h"
#include "filter.h"
#ifndef NORADIUS
#include "radius.h"
#endif
#include "bundle.h"
#include "iface.h"
#include "arp.h"
/*
* 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); \
addr.sa_len = sizeof(addr);
#if RTM_VERSION >= 3
/*
* arp_SetProxy - Make a proxy ARP entry for the peer.
*/
static struct {
struct rt_msghdr hdr;
struct sockaddr_inarp dst;
struct sockaddr_dl hwa;
char extra[128];
} arpmsg;
static int
arp_ProxySub(struct bundle *bundle, struct in_addr addr, int add, int s)
{
int routes;
/*
* Get the hardware address of an interface on the same subnet as our local
* address.
*/
memset(&arpmsg, 0, sizeof arpmsg);
if (!arp_EtherAddr(s, addr, &arpmsg.hwa, 0)) {
log_Printf(LogWARN, "%s: Cannot determine ethernet address for proxy ARP\n",
inet_ntoa(addr));
return 0;
}
routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET);
if (routes < 0) {
log_Printf(LogERROR, "arp_SetProxy: opening routing socket: %s\n",
strerror(errno));
return 0;
}
arpmsg.hdr.rtm_type = add ? RTM_ADD : RTM_DELETE;
arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC;
arpmsg.hdr.rtm_version = RTM_VERSION;
arpmsg.hdr.rtm_seq = ++bundle->routing_seq;
arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY;
arpmsg.hdr.rtm_inits = RTV_EXPIRE;
arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp);
arpmsg.dst.sin_family = AF_INET;
arpmsg.dst.sin_addr.s_addr = addr.s_addr;
arpmsg.dst.sin_other = SIN_PROXY;
arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg
+ arpmsg.hwa.sdl_len;
if (ID0write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0 &&
!(!add && errno == ESRCH)) {
log_Printf(LogERROR, "%s proxy arp entry %s: %s\n",
add ? "Add" : "Delete", inet_ntoa(addr), strerror(errno));
close(routes);
return 0;
}
close(routes);
return 1;
}
int
arp_SetProxy(struct bundle *bundle, struct in_addr addr, int s)
{
return (arp_ProxySub(bundle, addr, 1, s));
}
/*
* arp_ClearProxy - Delete the proxy ARP entry for the peer.
*/
int
arp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s)
{
return (arp_ProxySub(bundle, addr, 0, s));
}
#else /* RTM_VERSION */
/*
* arp_SetProxy - Make a proxy ARP entry for the peer.
*/
int
arp_SetProxy(struct bundle *bundle, struct in_addr addr, int s)
{
struct arpreq arpreq;
struct {
struct sockaddr_dl sdl;
char space[128];
} dls;
memset(&arpreq, '\0', sizeof arpreq);
/*
* Get the hardware address of an interface on the same subnet as our local
* address.
*/
if (!arp_EtherAddr(s, addr, &dls.sdl, 1)) {
log_Printf(LOG_PHASE_BIT, "Cannot determine ethernet address for "
"proxy ARP\n");
return 0;
}
arpreq.arp_ha.sa_len = sizeof(struct sockaddr);
arpreq.arp_ha.sa_family = AF_UNSPEC;
memcpy(arpreq.arp_ha.sa_data, LLADDR(&dls.sdl), dls.sdl.sdl_alen);
SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr;
arpreq.arp_flags = ATF_PERM | ATF_PUBL;
if (ID0ioctl(s, SIOCSARP, (caddr_t) & arpreq) < 0) {
log_Printf(LogERROR, "arp_SetProxy: ioctl(SIOCSARP): %s\n",
strerror(errno));
return 0;
}
return 1;
}
/*
* arp_ClearProxy - Delete the proxy ARP entry for the peer.
*/
int
arp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s)
{
struct arpreq arpreq;
memset(&arpreq, '\0', sizeof arpreq);
SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr;
if (ID0ioctl(s, SIOCDARP, (caddr_t) & arpreq) < 0) {
log_Printf(LogERROR, "arp_ClearProxy: ioctl(SIOCDARP): %s\n",
strerror(errno));
return 0;
}
return 1;
}
#endif /* RTM_VERSION */
/*
* arp_EtherAddr - get the hardware address of an interface on the
* the same subnet as ipaddr.
*/
int
arp_EtherAddr(int s, struct in_addr ipaddr, struct sockaddr_dl *hwaddr,
int verbose)
{
struct sockaddr_dl *dl = NULL;
struct ifaddrs *ifa, *ifap;
int skip = 1;
if (getifaddrs(&ifap) != 0) {
log_Printf(LogERROR, "arp_EtherAddr: getifaddrs: %s\n", strerror(errno));
return 0;
}
for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
if (ifa->ifa_addr->sa_family == AF_LINK) {
dl = (struct sockaddr_dl *)ifa->ifa_addr;
skip = (ifa->ifa_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT |
IFF_NOARP | IFF_LOOPBACK)) != (IFF_UP | IFF_BROADCAST);
continue;
}
if (skip)
/* Skip unusable interface */
continue;
/* Found a candidate. Do the addresses match ? */
if (log_IsKept(LogDEBUG))
log_Printf(LogDEBUG, "%.*s interface is a candidate for proxy\n",
dl->sdl_nlen, dl->sdl_data);
if (ifa->ifa_addr->sa_family == AF_INET) {
struct sockaddr_in *addr, *netmask;
addr = (struct sockaddr_in *)ifa->ifa_addr;
netmask = (struct sockaddr_in *)ifa->ifa_netmask;
if (log_IsKept(LogDEBUG)) {
char a[16];
strncpy(a, inet_ntoa(netmask->sin_addr), sizeof a - 1);
a[sizeof a - 1] = '\0';
log_Printf(LogDEBUG, "Check addr %s, mask %s\n",
inet_ntoa(addr->sin_addr), a);
}
if ((addr->sin_addr.s_addr & netmask->sin_addr.s_addr) ==
(ipaddr.s_addr & netmask->sin_addr.s_addr)) {
log_Printf(verbose ? LogPHASE : LogDEBUG,
"Found interface %.*s for %s\n", dl->sdl_nlen,
dl->sdl_data, inet_ntoa(ipaddr));
memcpy(hwaddr, dl, dl->sdl_len);
freeifaddrs(ifap);
return 1;
}
}
}
freeifaddrs(ifap);
return 0;
}