356 lines
9.2 KiB
C
356 lines
9.2 KiB
C
/*
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* sys-bsd.c - System-dependent procedures for setting up
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* PPP interfaces on bsd-4.4-ish systems (including 386BSD, NetBSD, etc.)
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*
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* Copyright (c) 1989 Carnegie Mellon University.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by Carnegie Mellon University. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* $Id: arp.c,v 1.26 1998/01/23 22:29:16 brian Exp $
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*
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*/
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/*
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* TODO:
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*/
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <net/if_dl.h>
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#include <netinet/in.h>
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#include <net/if_types.h>
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#include <netinet/if_ether.h>
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#include <arpa/inet.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/errno.h>
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#include <sys/ioctl.h>
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#include <sys/sysctl.h>
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#include <sys/uio.h>
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#include <unistd.h>
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#include "command.h"
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#include "mbuf.h"
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#include "log.h"
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#include "id.h"
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#include "route.h"
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#include "arp.h"
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#ifdef DEBUG
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/*
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* To test the proxy arp stuff, just
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*
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* cc -o arp-test -DDEBUG arp.c
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*
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*/
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#define LogIsKept(x) 1
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#define LogPrintf fprintf
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#undef LogDEBUG
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#define LogDEBUG stderr
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#undef LogERROR
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#define LogERROR stderr
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#undef LogPHASE
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#define LogPHASE stdout
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#define ID0socket socket
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#define ID0ioctl ioctl
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#endif
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static int rtm_seq;
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static int get_ether_addr(int, struct in_addr, struct sockaddr_dl *);
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/*
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* SET_SA_FAMILY - set the sa_family field of a struct sockaddr,
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* if it exists.
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*/
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#define SET_SA_FAMILY(addr, family) \
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memset((char *) &(addr), '\0', sizeof(addr)); \
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addr.sa_family = (family); \
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addr.sa_len = sizeof(addr);
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#if RTM_VERSION >= 3
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/*
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* sifproxyarp - Make a proxy ARP entry for the peer.
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*/
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static struct {
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struct rt_msghdr hdr;
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struct sockaddr_inarp dst;
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struct sockaddr_dl hwa;
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char extra[128];
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} arpmsg;
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static int arpmsg_valid;
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int
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sifproxyarp(int unit, struct in_addr hisaddr)
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{
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int routes;
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/*
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* Get the hardware address of an interface on the same subnet as our local
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* address.
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*/
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memset(&arpmsg, 0, sizeof arpmsg);
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if (!get_ether_addr(unit, hisaddr, &arpmsg.hwa)) {
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LogPrintf(LogERROR, "Cannot determine ethernet address for proxy ARP\n");
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return 0;
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}
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routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET);
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if (routes < 0) {
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LogPrintf(LogERROR, "sifproxyarp: opening routing socket: %s\n",
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strerror(errno));
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return 0;
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}
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arpmsg.hdr.rtm_type = RTM_ADD;
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arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC;
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arpmsg.hdr.rtm_version = RTM_VERSION;
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arpmsg.hdr.rtm_seq = ++rtm_seq;
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arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY;
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arpmsg.hdr.rtm_inits = RTV_EXPIRE;
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arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp);
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arpmsg.dst.sin_family = AF_INET;
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arpmsg.dst.sin_addr.s_addr = hisaddr.s_addr;
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arpmsg.dst.sin_other = SIN_PROXY;
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arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg
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+ arpmsg.hwa.sdl_len;
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if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
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LogPrintf(LogERROR, "Add proxy arp entry: %s\n", strerror(errno));
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close(routes);
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return 0;
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}
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close(routes);
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arpmsg_valid = 1;
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return 1;
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}
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/*
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* cifproxyarp - Delete the proxy ARP entry for the peer.
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*/
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int
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cifproxyarp(int unit, struct in_addr hisaddr)
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{
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int routes;
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if (!arpmsg_valid)
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return 0;
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arpmsg_valid = 0;
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arpmsg.hdr.rtm_type = RTM_DELETE;
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arpmsg.hdr.rtm_seq = ++rtm_seq;
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routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET);
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if (routes < 0) {
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LogPrintf(LogERROR, "sifproxyarp: opening routing socket: %s\n",
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strerror(errno));
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return 0;
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}
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if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) {
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LogPrintf(LogERROR, "Delete proxy arp entry: %s\n", strerror(errno));
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close(routes);
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return 0;
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}
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close(routes);
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return 1;
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}
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#else /* RTM_VERSION */
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/*
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* sifproxyarp - Make a proxy ARP entry for the peer.
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*/
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int
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sifproxyarp(int unit, struct in_addr hisaddr)
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{
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struct arpreq arpreq;
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struct {
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struct sockaddr_dl sdl;
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char space[128];
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} dls;
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memset(&arpreq, '\0', sizeof arpreq);
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/*
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* Get the hardware address of an interface on the same subnet as our local
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* address.
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*/
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if (!get_ether_addr(unit, hisaddr, &dls.sdl)) {
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LogPrintf(LOG_PHASE_BIT, "Cannot determine ethernet address for proxy ARP\n");
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return 0;
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}
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arpreq.arp_ha.sa_len = sizeof(struct sockaddr);
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arpreq.arp_ha.sa_family = AF_UNSPEC;
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memcpy(arpreq.arp_ha.sa_data, LLADDR(&dls.sdl), dls.sdl.sdl_alen);
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SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
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((struct sockaddr_in *) & arpreq.arp_pa)->sin_addr.s_addr = hisaddr.s_addr;
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arpreq.arp_flags = ATF_PERM | ATF_PUBL;
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if (ID0ioctl(unit, SIOCSARP, (caddr_t) & arpreq) < 0) {
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LogPrintf(LogERROR, "sifproxyarp: ioctl(SIOCSARP): %s\n", strerror(errno));
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return 0;
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}
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return 1;
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}
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/*
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* cifproxyarp - Delete the proxy ARP entry for the peer.
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*/
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int
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cifproxyarp(int unit, struct in_addr hisaddr)
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{
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struct arpreq arpreq;
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memset(&arpreq, '\0', sizeof arpreq);
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SET_SA_FAMILY(arpreq.arp_pa, AF_INET);
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((struct sockaddr_in *) & arpreq.arp_pa)->sin_addr.s_addr = hisaddr.s_addr;
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if (ID0ioctl(unit, SIOCDARP, (caddr_t) & arpreq) < 0) {
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LogPrintf(LogERROR, "cifproxyarp: ioctl(SIOCDARP): %s\n", strerror(errno));
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return 0;
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}
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return 1;
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}
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#endif /* RTM_VERSION */
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/*
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* get_ether_addr - get the hardware address of an interface on the
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* the same subnet as ipaddr.
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*/
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static int
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get_ether_addr(int s, struct in_addr ipaddr, struct sockaddr_dl *hwaddr)
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{
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int mib[6], sa_len, skip, b;
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size_t needed;
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char *buf, *ptr, *end;
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struct if_msghdr *ifm;
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struct ifa_msghdr *ifam;
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struct sockaddr *sa;
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struct sockaddr_dl *dl;
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struct sockaddr_in *ifa, *mask;
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mib[0] = CTL_NET;
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mib[1] = PF_ROUTE;
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mib[2] = 0;
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mib[3] = 0;
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mib[4] = NET_RT_IFLIST;
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mib[5] = 0;
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if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) {
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LogPrintf(LogERROR, "get_ether_addr: sysctl: estimate: %s\n",
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strerror(errno));
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return 0;
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}
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if ((buf = malloc(needed)) == NULL)
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return 0;
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if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
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free(buf);
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return 0;
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}
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end = buf + needed;
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ptr = buf;
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while (ptr < end) {
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ifm = (struct if_msghdr *)ptr; /* On if_msghdr */
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if (ifm->ifm_type != RTM_IFINFO)
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break;
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dl = (struct sockaddr_dl *)(ifm + 1); /* Single _dl at end */
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skip = (ifm->ifm_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT |
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IFF_NOARP | IFF_LOOPBACK)) != (IFF_UP | IFF_BROADCAST);
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ptr += ifm->ifm_msglen; /* First ifa_msghdr */
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while (ptr < end) {
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ifam = (struct ifa_msghdr *)ptr; /* Next ifa_msghdr (alias) */
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if (ifam->ifam_type != RTM_NEWADDR) /* finished ? */
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break;
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sa = (struct sockaddr *)(ifam+1); /* pile of sa's at end */
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ptr += ifam->ifam_msglen;
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if (skip || (ifam->ifam_addrs & (RTA_NETMASK|RTA_IFA)) !=
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(RTA_NETMASK|RTA_IFA))
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continue;
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/* Found a candidate. Do the addresses match ? */
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if (LogIsKept(LogDEBUG) &&
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ptr == (char *)ifm + ifm->ifm_msglen + ifam->ifam_msglen)
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LogPrintf(LogDEBUG, "%.*s interface is a candidate for proxy\n",
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dl->sdl_nlen, dl->sdl_data);
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b = 1;
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ifa = mask = NULL;
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while (b < (RTA_NETMASK|RTA_IFA) && sa < (struct sockaddr *)ptr) {
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switch (b) {
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case RTA_IFA:
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ifa = (struct sockaddr_in *)sa;
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break;
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case RTA_NETMASK:
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/*
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* Careful here ! this sockaddr doesn't have sa_family set to
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* AF_INET, and is only 8 bytes big ! I have no idea why !
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*/
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mask = (struct sockaddr_in *)sa;
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break;
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}
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if (ifam->ifam_addrs & b) {
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#define ALN sizeof(ifa->sin_addr.s_addr)
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sa_len = sa->sa_len > 0 ? ((sa->sa_len-1)|(ALN-1))+1 : ALN;
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sa = (struct sockaddr *)((char *)sa + sa_len);
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}
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b <<= 1;
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}
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if (LogIsKept(LogDEBUG)) {
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char a[16];
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strncpy(a, inet_ntoa(mask->sin_addr), sizeof a - 1);
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a[sizeof a - 1] = '\0';
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LogPrintf(LogDEBUG, "Check addr %s, mask %s\n",
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inet_ntoa(ifa->sin_addr), a);
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}
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if (ifa->sin_family == AF_INET &&
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(ifa->sin_addr.s_addr & mask->sin_addr.s_addr) ==
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(ipaddr.s_addr & mask->sin_addr.s_addr)) {
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LogPrintf(LogPHASE, "Found interface %.*s for proxy arp\n",
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dl->sdl_alen, dl->sdl_data);
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memcpy(hwaddr, dl, dl->sdl_len);
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free(buf);
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return 1;
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}
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}
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}
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free(buf);
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return 0;
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}
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#ifdef DEBUG
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int
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main(int argc, char **argv)
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{
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struct in_addr ipaddr;
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int s, f;
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s = socket(AF_INET, SOCK_DGRAM, 0);
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for (f = 1; f < argc; f++) {
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if (inet_aton(argv[f], &ipaddr))
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sifproxyarp(s, ipaddr);
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}
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close(s);
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}
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#endif
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