freebsd-dev/usr.sbin/ppp/arp.c
Brian Somers 4147817ab9 Fix error message.
Don't complicate the test compilation mentioned at the start of
the file.
1998-01-24 00:03:14 +00:00

356 lines
9.2 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 1.26 1998/01/23 22:29:16 brian Exp $
*
*/
/*
* TODO:
*/
#include <sys/param.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/route.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <net/if_types.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>
#include <sys/uio.h>
#include <unistd.h>
#include "command.h"
#include "mbuf.h"
#include "log.h"
#include "id.h"
#include "route.h"
#include "arp.h"
#ifdef DEBUG
/*
* To test the proxy arp stuff, just
*
* cc -o arp-test -DDEBUG arp.c
*
*/
#define LogIsKept(x) 1
#define LogPrintf fprintf
#undef LogDEBUG
#define LogDEBUG stderr
#undef LogERROR
#define LogERROR stderr
#undef LogPHASE
#define LogPHASE stdout
#define ID0socket socket
#define ID0ioctl ioctl
#endif
static int rtm_seq;
static int get_ether_addr(int, struct in_addr, 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, struct in_addr 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.s_addr;
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, struct in_addr 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, struct in_addr 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.s_addr;
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, struct in_addr 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.s_addr;
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.
*/
static int
get_ether_addr(int s, struct in_addr ipaddr, struct sockaddr_dl *hwaddr)
{
int mib[6], sa_len, skip, b;
size_t needed;
char *buf, *ptr, *end;
struct if_msghdr *ifm;
struct ifa_msghdr *ifam;
struct sockaddr *sa;
struct sockaddr_dl *dl;
struct sockaddr_in *ifa, *mask;
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0;
mib[3] = 0;
mib[4] = NET_RT_IFLIST;
mib[5] = 0;
if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
LogPrintf(LogERROR, "get_ether_addr: sysctl: estimate: %s\n",
strerror(errno));
return 0;
}
if ((buf = malloc(needed)) == NULL)
return 0;
if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
free(buf);
return 0;
}
end = buf + needed;
ptr = buf;
while (ptr < end) {
ifm = (struct if_msghdr *)ptr; /* On if_msghdr */
if (ifm->ifm_type != RTM_IFINFO)
break;
dl = (struct sockaddr_dl *)(ifm + 1); /* Single _dl at end */
skip = (ifm->ifm_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT |
IFF_NOARP | IFF_LOOPBACK)) != (IFF_UP | IFF_BROADCAST);
ptr += ifm->ifm_msglen; /* First ifa_msghdr */
while (ptr < end) {
ifam = (struct ifa_msghdr *)ptr; /* Next ifa_msghdr (alias) */
if (ifam->ifam_type != RTM_NEWADDR) /* finished ? */
break;
sa = (struct sockaddr *)(ifam+1); /* pile of sa's at end */
ptr += ifam->ifam_msglen;
if (skip || (ifam->ifam_addrs & (RTA_NETMASK|RTA_IFA)) !=
(RTA_NETMASK|RTA_IFA))
continue;
/* Found a candidate. Do the addresses match ? */
if (LogIsKept(LogDEBUG) &&
ptr == (char *)ifm + ifm->ifm_msglen + ifam->ifam_msglen)
LogPrintf(LogDEBUG, "%.*s interface is a candidate for proxy\n",
dl->sdl_nlen, dl->sdl_data);
b = 1;
ifa = mask = NULL;
while (b < (RTA_NETMASK|RTA_IFA) && sa < (struct sockaddr *)ptr) {
switch (b) {
case RTA_IFA:
ifa = (struct sockaddr_in *)sa;
break;
case RTA_NETMASK:
/*
* Careful here ! this sockaddr doesn't have sa_family set to
* AF_INET, and is only 8 bytes big ! I have no idea why !
*/
mask = (struct sockaddr_in *)sa;
break;
}
if (ifam->ifam_addrs & b) {
#define ALN sizeof(ifa->sin_addr.s_addr)
sa_len = sa->sa_len > 0 ? ((sa->sa_len-1)|(ALN-1))+1 : ALN;
sa = (struct sockaddr *)((char *)sa + sa_len);
}
b <<= 1;
}
if (LogIsKept(LogDEBUG)) {
char a[16];
strncpy(a, inet_ntoa(mask->sin_addr), sizeof a - 1);
a[sizeof a - 1] = '\0';
LogPrintf(LogDEBUG, "Check addr %s, mask %s\n",
inet_ntoa(ifa->sin_addr), a);
}
if (ifa->sin_family == AF_INET &&
(ifa->sin_addr.s_addr & mask->sin_addr.s_addr) ==
(ipaddr.s_addr & mask->sin_addr.s_addr)) {
LogPrintf(LogPHASE, "Found interface %.*s for proxy arp\n",
dl->sdl_alen, dl->sdl_data);
memcpy(hwaddr, dl, dl->sdl_len);
free(buf);
return 1;
}
}
}
free(buf);
return 0;
}
#ifdef DEBUG
int
main(int argc, char **argv)
{
struct in_addr ipaddr;
int s, f;
s = socket(AF_INET, SOCK_DGRAM, 0);
for (f = 1; f < argc; f++) {
if (inet_aton(argv[f], &ipaddr))
sifproxyarp(s, ipaddr);
}
close(s);
}
#endif