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-rw-r--r--src/arp.c317
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diff --git a/src/arp.c b/src/arp.c
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+/*
+ * 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.
+ *
+ * $FreeBSD: src/usr.sbin/ppp/arp.c,v 1.46.26.1 2010/12/21 17:10:29 kensmith 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 <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 routes;
+
+ /*
+ * Get the hardware address of an interface on the same subnet as our local
+ * address.
+ */
+
+ memset(&arpmsg, 0, sizeof arpmsg);
+ if (!arp_EtherAddr(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)
+{
+ return (arp_ProxySub(bundle, addr, 1));
+}
+
+/*
+ * arp_ClearProxy - Delete the proxy ARP entry for the peer.
+ */
+int
+arp_ClearProxy(struct bundle *bundle, struct in_addr addr)
+{
+ return (arp_ProxySub(bundle, addr, 0));
+}
+
+#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(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(struct in_addr ipaddr, struct sockaddr_dl *hwaddr,
+ int verbose)
+{
+ int mib[6], skip;
+ size_t needed;
+ char *buf, *ptr, *end;
+ struct if_msghdr *ifm;
+ struct ifa_msghdr *ifam;
+ struct sockaddr_dl *dl;
+ struct sockaddr *sa[RTAX_MAX];
+
+ 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) {
+ log_Printf(LogERROR, "arp_EtherAddr: 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;
+ 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 (log_IsKept(LogDEBUG) &&
+ ptr == (char *)ifm + ifm->ifm_msglen + ifam->ifam_msglen)
+ log_Printf(LogDEBUG, "%.*s interface is a candidate for proxy\n",
+ dl->sdl_nlen, dl->sdl_data);
+
+ iface_ParseHdr(ifam, sa);
+
+ if (sa[RTAX_IFA]->sa_family == AF_INET) {
+ struct sockaddr_in *ifa, *netmask;
+
+ ifa = (struct sockaddr_in *)sa[RTAX_IFA];
+ netmask = (struct sockaddr_in *)sa[RTAX_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(ifa->sin_addr), a);
+ }
+
+ if ((ifa->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);
+ free(buf);
+ return 1;
+ }
+ }
+ }
+ }
+ free(buf);
+
+ return 0;
+}
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