1 files changed, 355 insertions, 0 deletions

diff --git a/usr.sbin/ppp/arp.c b/usr.sbin/ppp/arp.c
new file mode 100644
index 000000000000..b62f940cdb39
--- /dev/null
+++ b/usr.sbin/ppp/arp.c
@@ -0,0 +1,355 @@
+/*
+ * 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