freebsd-dev/usr.sbin/ppp/arp.c
Brian Somers 70ee81ff6b Cosmetic (style):
sizeof(var) -> sizeof var
  sizeof type -> sizeof(type)

Suggested by: J Wunsch <j@uriah.heep.sax.de>
1997-12-24 09:29:17 +00:00

315 lines
7.8 KiB
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.
*
* $Id: arp.c,v 1.19 1997/12/23 22:38:51 brian Exp $
*
*/
/*
* TODO:
*/
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <net/if.h>
#ifdef __FreeBSD__
#include <net/if_var.h>
#endif
#include <net/route.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <net/if_types.h>
#include <netinet/in_var.h>
#include <netinet/if_ether.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/uio.h>
#include <unistd.h>
#include "command.h"
#include "mbuf.h"
#include "log.h"
#include "id.h"
#include "arp.h"
static int rtm_seq;
static int get_ether_addr(int, u_long, struct sockaddr_dl *);
/*
* 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
/*
* sifproxyarp - 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 arpmsg_valid;
int
sifproxyarp(int unit, u_long hisaddr)
{
int routes;
/*
* Get the hardware address of an interface on the same subnet as our local
* address.
*/
memset(&arpmsg, 0, sizeof arpmsg);
if (!get_ether_addr(unit, hisaddr, &arpmsg.hwa)) {
LogPrintf(LogERROR, "Cannot determine ethernet address for proxy ARP\n");
return 0;
}
routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET);
if (routes < 0) {
LogPrintf(LogERROR, "sifproxyarp: opening routing socket: %s\n",
strerror(errno));
return 0;
}
arpmsg.hdr.rtm_type = RTM_ADD;
arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC;
arpmsg.hdr.rtm_version = RTM_VERSION;
arpmsg.hdr.rtm_seq = ++rtm_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 = hisaddr;
arpmsg.dst.sin_other = SIN_PROXY;
arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg
+ arpmsg.hwa.sdl_len;
if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
LogPrintf(LogERROR, "Add proxy arp entry: %s\n", strerror(errno));
close(routes);
return 0;
}
close(routes);
arpmsg_valid = 1;
return 1;
}
/*
* cifproxyarp - Delete the proxy ARP entry for the peer.
*/
int
cifproxyarp(int unit, u_long hisaddr)
{
int routes;
if (!arpmsg_valid)
return 0;
arpmsg_valid = 0;
arpmsg.hdr.rtm_type = RTM_DELETE;
arpmsg.hdr.rtm_seq = ++rtm_seq;
routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET);
if (routes < 0) {
LogPrintf(LogERROR, "sifproxyarp: opening routing socket: %s\n",
strerror(errno));
return 0;
}
if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
LogPrintf(LogERROR, "Delete proxy arp entry: %s\n", strerror(errno));
close(routes);
return 0;
}
close(routes);
return 1;
}
#else /* RTM_VERSION */
/*
* sifproxyarp - Make a proxy ARP entry for the peer.
*/
int
sifproxyarp(int unit, u_long hisaddr)
{
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 (!get_ether_addr(unit, hisaddr, &dls.sdl)) {
LogPrintf(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 = hisaddr;
arpreq.arp_flags = ATF_PERM | ATF_PUBL;
if (ID0ioctl(unit, SIOCSARP, (caddr_t) & arpreq) < 0) {
LogPrintf(LogERROR, "sifproxyarp: ioctl(SIOCSARP): %s\n", strerror(errno));
return 0;
}
return 1;
}
/*
* cifproxyarp - Delete the proxy ARP entry for the peer.
*/
int
cifproxyarp(int unit, u_long hisaddr)
{
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 = hisaddr;
if (ID0ioctl(unit, SIOCDARP, (caddr_t) & arpreq) < 0) {
LogPrintf(LogERROR, "cifproxyarp: ioctl(SIOCDARP): %s\n", strerror(errno));
return 0;
}
return 1;
}
#endif /* RTM_VERSION */
/*
* get_ether_addr - get the hardware address of an interface on the
* the same subnet as ipaddr.
*/
#define MAX_IFS 32
static int
get_ether_addr(int s, u_long ipaddr, struct sockaddr_dl *hwaddr)
{
struct ifreq *ifr, *ifend, *ifp;
u_long ina, mask;
struct sockaddr_dl *dla;
struct ifreq ifreq;
struct ifconf ifc;
struct ifreq ifs[MAX_IFS];
ifc.ifc_len = sizeof ifs;
ifc.ifc_req = ifs;
if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
LogPrintf(LogERROR, "get_ether_addr: ioctl(SIOCGIFCONF): %s\n",
strerror(errno));
return 0;
}
/*
* Scan through looking for an interface with an Internet address on the
* same subnet as `ipaddr'.
*/
ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
for (ifr = ifc.ifc_req; ifr < ifend;) {
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 - 1);
ifreq.ifr_name[sizeof ifreq.ifr_name - 1] = '\0';
/*
* Check that the interface is up, and not point-to-point or loopback.
*/
if (ioctl(s, SIOCGIFFLAGS, &ifreq) < 0)
continue;
if ((ifreq.ifr_flags &
(IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT | IFF_LOOPBACK | IFF_NOARP))
!= (IFF_UP | IFF_BROADCAST))
goto nextif;
/*
* Get its netmask and check that it's on the right subnet.
*/
if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0)
continue;
mask = ((struct sockaddr_in *) & ifreq.ifr_addr)->sin_addr.s_addr;
if ((ipaddr & mask) != (ina & mask))
goto nextif;
break;
}
nextif:
ifr = (struct ifreq *) ((char *) &ifr->ifr_addr + ifr->ifr_addr.sa_len);
}
if (ifr >= ifend)
return 0;
LogPrintf(LogPHASE, "Found interface %s for proxy arp\n", ifr->ifr_name);
/*
* Now scan through again looking for a link-level address for this
* interface.
*/
ifp = ifr;
for (ifr = ifc.ifc_req; ifr < ifend;) {
if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0
&& ifr->ifr_addr.sa_family == AF_LINK) {
/*
* Found the link-level address - copy it out
*/
dla = (struct sockaddr_dl *) & ifr->ifr_addr;
memcpy(hwaddr, dla, dla->sdl_len);
return 1;
}
ifr = (struct ifreq *) ((char *) &ifr->ifr_addr + ifr->ifr_addr.sa_len);
}
return 0;
}
#ifdef DEBUG
int
main()
{
u_long ipaddr;
int s;
s = socket(AF_INET, SOCK_DGRAM, 0);
ipaddr = inet_addr("192.168.1.32");
sifproxyarp(s, ipaddr);
close(s);
}
#endif