Solve the ``first connection'' problem that occurs on

demand-dial links with dynamic IP numbers where the program
that causes the dial bind()s to an interface address that is
subsequently changed after ppp negotiation.

The problem is defeated by adding negotiated addresses to the
tun interface as additional alias addresses and providing a set
of ``iface'' commands for managing the interface.  Libalias is
also required (and what a name clash!) - it happily IP-aliases
the address so that the source is that of the primary (negotiated)
interface and un-IP-aliases it on the way back.

An ``enable iface-alias'' is done implicitly by the -alias command
line switch.  If -alias isn't given, iface-aliasing is disabled by
default and can't be enabled 'till an ``alias enable yes'' is done.
``alias enable no'' silently disables iface-alias.

So, for dynamic-IP-type-connections, running ``ppp -alias -auto blah''
will work for the first connection, although existing bindings will
not survive a disconnect/connect as the TCP peer will be trying to
send to the old IP address - the packets won't route.

It's now a lot easier to add IPXCP to ppp with minor updates to
the new iface.[ch] (if anyone ever gets 'round to it).

It's also now possible to manually add interface aliases with
something like ``iface add 1.2.3.4/24 5.6.7.8''.  This allows
multi-homed ppp links :-)

1 files changed, 431 insertions, 0 deletions

diff --git a/usr.sbin/ppp/iface.c b/usr.sbin/ppp/iface.c
new file mode 100644
index 0000000..c217690
--- /dev/null
+++ b/usr.sbin/ppp/iface.c
@@ -0,0 +1,431 @@
+/*-
+ * Copyright (c) 1998 Brian Somers <brian@Awfulhak.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	$Id:$
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <net/if.h>
+#include <net/if_dl.h>
+#include <net/route.h>
+#include <arpa/inet.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <sys/un.h>
+
+#include <sys/errno.h>
+#include <sys/ioctl.h>
+#include <sys/sysctl.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <termios.h>
+#include <unistd.h>
+
+#include "defs.h"
+#include "command.h"
+#include "mbuf.h"
+#include "log.h"
+#include "id.h"
+#include "timer.h"
+#include "fsm.h"
+#include "iplist.h"
+#include "lqr.h"
+#include "hdlc.h"
+#include "throughput.h"
+#include "slcompress.h"
+#include "filter.h"
+#include "descriptor.h"
+#include "ipcp.h"
+#include "lcp.h"
+#include "ccp.h"
+#include "link.h"
+#include "mp.h"
+#include "bundle.h"
+#include "prompt.h"
+#include "iface.h"
+
+
+static int
+bitsinmask(struct in_addr mask)
+{
+  u_int32_t bitmask, maskaddr;
+  int bits;
+
+  bitmask = 0xffffffff;
+  maskaddr = ntohl(mask.s_addr);
+  for (bits = 32; bits >= 0; bits--) {
+    if (maskaddr == bitmask)
+      break;
+    bitmask &= ~(1 << (32 - bits));
+  }
+
+  return bits;
+}
+
+struct iface *
+iface_Create(const char *name)
+{
+  int mib[6], i, s;
+  size_t needed;
+  char *buf, *ptr, *end, *cp, *lim;
+  struct if_msghdr *ifm;
+  struct ifa_msghdr *ifam;
+  struct sockaddr_dl *dl;
+  struct rt_addrinfo rti;
+  struct iface *iface;
+  struct iface_addr *addr;
+
+  s = socket(AF_INET, SOCK_DGRAM, 0);
+  if (s < 0) {
+    fprintf(stderr, "iface_Create: socket(): %s\n", strerror(errno));
+    return NULL;
+  }
+
+  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) {
+    fprintf(stderr, "clean: sysctl: estimate: %s\n",
+              strerror(errno));
+    close(s);
+    return NULL;
+  }
+
+  if ((buf = (char *)malloc(needed)) == NULL) {
+    close(s);
+    return NULL;
+  }
+
+  if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
+    free(buf);
+    close(s);
+    return NULL;
+  }
+
+  ptr = buf;
+  end = buf + needed;
+  iface = NULL;
+
+  while (ptr < end && iface == NULL) {
+    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 */
+    if (!strncmp(name, dl->sdl_data, dl->sdl_nlen)) {
+      iface = (struct iface *)malloc(sizeof *iface);
+      if (iface == NULL) {
+        fprintf(stderr, "iface_Create: malloc: %s\n", strerror(errno));
+        return NULL;
+      }
+      iface->name = strdup(name);
+      iface->flags = ifm->ifm_flags;
+      iface->index = ifm->ifm_index;
+      iface->in_addrs = 0;
+      iface->in_addr = NULL;
+    }
+    ptr += ifm->ifm_msglen;				/* First ifa_msghdr */
+    for (; ptr < end; ptr += ifam->ifam_msglen) {
+      ifam = (struct ifa_msghdr *)ptr;			/* Next if address */
+
+      if (ifam->ifam_type != RTM_NEWADDR)		/* finished this if */
+        break;
+
+      if (iface == NULL)				/* Keep wading */
+        continue;
+
+      /* Found an address ! */
+
+      if (ifam->ifam_addrs & (1 << RTAX_IFA)) {
+        /* *And* it's configured ! */
+        rti.rti_addrs = ifam->ifam_addrs;
+        lim = (char *)ifam + ifam->ifam_msglen;
+        cp = (char *)(ifam + 1);
+        memset(rti.rti_info, '\0', sizeof(rti.rti_info));
+        for (i = 0; i < RTAX_MAX && cp < lim; i++) {
+          if ((rti.rti_addrs & (1 << i)) == 0)
+            continue;
+          rti.rti_info[i] = (struct sockaddr *)cp;
+#define ROUNDUP(x) \
+          ((x) > 0 ? (1 + (((x) - 1) | (sizeof(long) - 1))) : sizeof(long))
+          cp += ROUNDUP(rti.rti_info[i]->sa_len);
+        }
+
+        if (rti.rti_info[RTAX_IFA] &&
+            rti.rti_info[RTAX_IFA]->sa_family == AF_INET) {
+          /* Record the iface address rti */
+
+          addr = (struct iface_addr *)realloc
+            (iface->in_addr, (iface->in_addrs + 1) * sizeof iface->in_addr[0]);
+          if (addr == NULL)
+            break;
+          iface->in_addr = addr;
+
+          addr += iface->in_addrs;
+          iface->in_addrs++;
+
+          addr->ifa.s_addr = ((struct sockaddr_in *)rti.rti_info[RTAX_IFA])->
+            sin_addr.s_addr;
+          addr->brd.s_addr = rti.rti_info[RTAX_BRD] ?
+            ((struct sockaddr_in *)rti.rti_info[RTAX_BRD])->sin_addr.s_addr :
+            INADDR_ANY;
+          addr->mask.s_addr = rti.rti_info[RTAX_NETMASK] ?
+            ((struct sockaddr_in *)rti.rti_info[RTAX_NETMASK])->sin_addr.s_addr:
+            INADDR_ANY;
+
+          addr->bits = bitsinmask(addr->mask);
+        }
+      }
+    }
+  }
+
+  free(buf);
+  close(s);
+
+  return iface;
+}
+
+static void
+iface_addr_Zap(const char *name, struct iface_addr *addr)
+{
+  struct ifaliasreq ifra;
+  struct sockaddr_in *me, *peer;
+  int s;
+
+  s = ID0socket(AF_INET, SOCK_DGRAM, 0);
+  if (s < 0)
+    log_Printf(LogERROR, "iface_addr_Zap: socket(): %s\n", strerror(errno));
+  else {
+    memset(&ifra, '\0', sizeof ifra);
+    strncpy(ifra.ifra_name, name, sizeof ifra.ifra_name - 1);
+    me = (struct sockaddr_in *)&ifra.ifra_addr;
+    peer = (struct sockaddr_in *)&ifra.ifra_broadaddr;
+    me->sin_family = peer->sin_family = AF_INET;
+    me->sin_len = peer->sin_len = sizeof(struct sockaddr_in);
+    me->sin_addr = addr->ifa;
+    peer->sin_addr = addr->brd;
+    if (ID0ioctl(s, SIOCDIFADDR, &ifra) < 0)
+      log_Printf(LogWARN, "iface_addr_Zap: ioctl(SIOCDIFADDR, %s): %s\n",
+                 inet_ntoa(addr->ifa), strerror(errno));
+    close(s);
+  }
+}
+
+void
+iface_inClear(struct iface *iface, int how)
+{
+  int n, addrs;
+
+  addrs = n = how == IFACE_CLEAR_ALL ? 0 : 1;
+  for (; n < iface->in_addrs; n++)
+    iface_addr_Zap(iface->name, iface->in_addr + n);
+
+  iface->in_addrs = addrs;
+  /* Don't bother realloc()ing - we have little to gain */
+}
+
+int
+iface_inAdd(struct iface *iface, struct in_addr ifa, struct in_addr mask,
+            struct in_addr brd, int how)
+{
+  int slot, s;
+  struct ifaliasreq ifra;
+  struct sockaddr_in *me, *peer, *msk;
+  struct iface_addr *addr;
+
+  for (slot = 0; slot < iface->in_addrs; slot++)
+    if (iface->in_addr[slot].ifa.s_addr == ifa.s_addr) {
+      if (how & IFACE_FORCE_ADD)
+        break;
+      else
+        /* errno = EEXIST; */
+        return 0;
+    }
+
+  addr = (struct iface_addr *)realloc
+    (iface->in_addr, (iface->in_addrs + 1) * sizeof iface->in_addr[0]);
+  if (addr == NULL) {
+    log_Printf(LogERROR, "iface_inAdd: realloc: %s\n", strerror(errno));
+    return 0;
+  }
+  iface->in_addr = addr;
+
+  s = ID0socket(AF_INET, SOCK_DGRAM, 0);
+  if (s < 0) {
+    log_Printf(LogERROR, "iface_inAdd: socket(): %s\n", strerror(errno));
+    return 0;
+  }
+
+  memset(&ifra, '\0', sizeof ifra);
+  strncpy(ifra.ifra_name, iface->name, sizeof ifra.ifra_name - 1);
+
+  me = (struct sockaddr_in *)&ifra.ifra_addr;
+  msk = (struct sockaddr_in *)&ifra.ifra_mask;
+  peer = (struct sockaddr_in *)&ifra.ifra_broadaddr;
+
+  me->sin_family = msk->sin_family = peer->sin_family = AF_INET;
+  me->sin_len = msk->sin_len = peer->sin_len = sizeof(struct sockaddr_in);
+
+  me->sin_addr = ifa;
+  msk->sin_addr = mask;
+  peer->sin_addr = brd;
+
+  /*
+   * Note: EEXIST is sometimes returned, despite the route actually being
+   *       added !
+   */
+  if (ID0ioctl(s, SIOCAIFADDR, &ifra) < 0 && errno != EEXIST) {
+    log_Printf(LogERROR, "iface_inAdd: ioctl(SIOCAIFADDR): %s\n",
+               strerror(errno));
+    close(s);
+    return 0;
+  }
+  close(s);
+
+  if (slot == iface->in_addrs) {
+    /* We're adding a new interface address */
+
+    if (how & IFACE_ADD_FIRST) {
+      /* Stuff it at the start of our list */
+      slot = 0;
+      bcopy(iface->in_addr, iface->in_addr + 1,
+            iface->in_addrs * sizeof iface->in_addr[0]);
+    }
+
+    iface->in_addrs++;
+  } else if (how & IFACE_ADD_FIRST) {
+    /* Shift it up to the first slot */
+    bcopy(iface->in_addr, iface->in_addr + 1, slot * sizeof iface->in_addr[0]);
+    slot = 0;
+  }
+
+  iface->in_addr[slot].ifa = ifa;
+  iface->in_addr[slot].mask = mask;
+  iface->in_addr[slot].brd = brd;
+  iface->in_addr[slot].bits = bitsinmask(iface->in_addr[slot].mask);
+
+  return 1;
+}
+
+int
+iface_inDelete(struct iface *iface, struct in_addr ip)
+{
+  int n;
+
+  for (n = 0; n < iface->in_addrs; n++)
+    if (iface->in_addr[n].ifa.s_addr == ip.s_addr) {
+      iface_addr_Zap(iface->name, iface->in_addr + n);
+      bcopy(iface->in_addr + n + 1, iface->in_addr + n,
+            (iface->in_addrs - n - 1) * sizeof iface->in_addr[0]);
+      iface->in_addrs--;
+      return 1;
+    }
+
+  return 0;
+}
+
+void
+iface_Destroy(struct iface *iface)
+{
+  /*
+   * iface_Clear(iface, IFACE_CLEAR_ALL) must be called manually
+   * if that's what the user wants.  It's better to leave the interface
+   * allocated so that existing connections can continue to work.
+   */
+
+  if (iface != NULL) {
+    free(iface->name);
+    free(iface->in_addr);
+    free(iface);
+  }
+}
+
+#define if_entry(x) { IFF_##x, #x }
+
+struct {
+  int flag;
+  const char *value;
+} if_flags[] = {
+  if_entry(UP),
+  if_entry(BROADCAST),
+  if_entry(DEBUG),
+  if_entry(LOOPBACK),
+  if_entry(POINTOPOINT),
+  if_entry(RUNNING),
+  if_entry(NOARP),
+  if_entry(PROMISC),
+  if_entry(ALLMULTI),
+  if_entry(OACTIVE),
+  if_entry(SIMPLEX),
+  if_entry(LINK0),
+  if_entry(LINK1),
+  if_entry(LINK2),
+  if_entry(MULTICAST),
+  { 0, "???" }
+};
+
+int
+iface_Show(struct cmdargs const *arg)
+{
+  struct iface *iface = arg->bundle->iface, *current;
+  int f, flags;
+
+  current = iface_Create(iface->name);
+  flags = iface->flags = current->flags;
+  iface_Destroy(current);
+
+  prompt_Printf(arg->prompt, "%s (idx %d) <", iface->name, iface->index);
+  for (f = 0; f < sizeof if_flags / sizeof if_flags[0]; f++)
+    if ((if_flags[f].flag & flags) || (!if_flags[f].flag && flags)) {
+      prompt_Printf(arg->prompt, "%s%s", flags == iface->flags ? "" : ",",
+                    if_flags[f].value);
+      flags &= ~if_flags[f].flag;
+    }
+  prompt_Printf(arg->prompt, "> has %d address%s:\n", iface->in_addrs,
+                iface->in_addrs == 1 ? "" : "es");
+
+  for (f = 0; f < iface->in_addrs; f++) {
+    prompt_Printf(arg->prompt, "  %s", inet_ntoa(iface->in_addr[f].ifa));
+    if (iface->in_addr[f].bits >= 0)
+      prompt_Printf(arg->prompt, "/%d", iface->in_addr[f].bits);
+    if (iface->flags & IFF_POINTOPOINT)
+      prompt_Printf(arg->prompt, " -> %s", inet_ntoa(iface->in_addr[f].brd));
+    else if (iface->flags & IFF_BROADCAST)
+      prompt_Printf(arg->prompt, " broadcast %s",
+                    inet_ntoa(iface->in_addr[f].brd));
+    if (iface->in_addr[f].bits < 0)
+      prompt_Printf(arg->prompt, " (mask %s)",
+                    inet_ntoa(iface->in_addr[f].mask));
+    prompt_Printf(arg->prompt, "\n");
+  }
+
+  return 0;
+}