NetBSD/usr.sbin/amd/libamu/wire.c

/*
 * Copyright (c) 1997 Erez Zadok
 * Copyright (c) 1990 Jan-Simon Pendry
 * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry at Imperial College, London.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      %W% (Berkeley) %G%
 *
 * $Id: wire.c,v 1.1.1.1 1997/07/24 21:20:09 christos Exp $
 *
 */

/*
 * This function returns the subnet (address&netmask) for the primary network
 * interface.  If the resulting address has an entry in the hosts file, the
 * corresponding name is retuned, otherwise the address is returned in
 * standard internet format.
 * As a side-effect, a list of local IP/net address is recorded for use
 * by the islocalnet() function.
 *
 * Derived from original by Paul Anderson (23/4/90)
 * Updates from Dirk Grunwald (11/11/91)
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <am_defs.h>
#include <amu.h>


/*
 * List of locally connected networks
 */
typedef struct addrlist addrlist;
struct addrlist {
  addrlist *ip_next;
  u_long ip_addr;
  u_long ip_mask;
};
static addrlist *localnets = 0;

#if defined(IFF_LOCAL_LOOPBACK) && !defined(IFF_LOOPBACK)
# define IFF_LOOPBACK	IFF_LOCAL_LOOPBACK
#endif /* defined(IFF_LOCAL_LOOPBACK) && !defined(IFF_LOOPBACK) */

#if defined(HAVE_FIELD_STRUCT_IFREQ_IFR_ADDR) && defined(HAVE_FIELD_STRUCT_SOCKADDR_SA_LEN)
# define SIZE(ifr)	(MAX((ifr)->ifr_addr.sa_len, sizeof((ifr)->ifr_addr)) + sizeof(ifr->ifr_name))
#else /* not defined(HAVE_FIELD_STRUCT_IFREQ_IFR_ADDR) && defined(HAVE_FIELD_STRUCT_SOCKADDR_SA_LEN) */
# define SIZE(ifr)	sizeof(*ifr)
#endif /* not defined(HAVE_FIELD_STRUCT_IFREQ_IFR_ADDR) && defined(HAVE_FIELD_STRUCT_SOCKADDR_SA_LEN) */

#define C(x)		((x) & 0xff)
#define GFBUFLEN	1024
#define clist		(ifc.ifc_ifcu.ifcu_req)
#define count		(ifc.ifc_len/sizeof(struct ifreq))


void
getwire(char **name1, char **number1, char **name2, char **number2)
{
  struct hostent *hp;
  struct netent *np;
  struct ifconf ifc;
  struct ifreq *ifr;
  caddr_t cp, cplim;
  u_long address, netmask, subnet;
  char buf[GFBUFLEN], *s;
  int fd = -1;
  u_long net;
  u_long mask;
  u_long subnetshift;
  char netNumberBuf[64];

#ifndef SIOCGIFFLAGS
  /* if cannot get interface flags, return nothing */
  *name1 = strdup("no_subnet_known");
  *number1 = "0.0.0.0";
  *name2 = 0;
  *number2 = 0;
  return;
#endif /* not SIOCGIFFLAGS */

  *name1 = 0;
  *number1 = 0;
  *name2 = 0;
  *number2 = 0;

  /*
   * Get suitable socket
   */
  if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
    goto out;

  /*
   * Fill in ifconf details
   */
  memset(&buf[0], 0, GFBUFLEN);
  ifc.ifc_len = sizeof(buf);
  ifc.ifc_buf = buf;

  /*
   * Get network interface configurations
   */
  if (ioctl(fd, SIOCGIFCONF, (caddr_t) & ifc) < 0)
    goto out;

  /*
   * Upper bound on array
   */
  cplim = buf + ifc.ifc_len;

  /*
   * This is some magic to cope with both "traditional" and the
   * new 4.4BSD-style struct sockaddrs.  The new structure has
   * variable length and a size field to support longer addresses.
   * AF_LINK is a new definition for 4.4BSD.
   */

  /*
   * Scan the list looking for a suitable interface
   */
  for (cp = buf; cp < cplim; cp += SIZE(ifr)) {
    addrlist *al;
    ifr = (struct ifreq *) cp;

    if (ifr->ifr_addr.sa_family != AF_INET)
      continue;
    else
      address = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr;

    /*
     * Get interface flags
     */
    if (ioctl(fd, SIOCGIFFLAGS, (caddr_t) ifr) < 0)
      continue;

    /*
     * If the interface is a loopback, or its not running
     * then ignore it.
     */
#ifdef IFF_LOOPBACK
    if ((ifr->ifr_flags & IFF_LOOPBACK) != 0)
      continue;
#endif /* IFF_LOOPBACK */

    /* if the interface is not UP or not RUNNING, skip it */
    if ((ifr->ifr_flags & IFF_RUNNING) == 0 ||
	(ifr->ifr_flags & IFF_UP) == 0)
      continue;

    /*
     * Get the netmask of this interface
     */
    if (ioctl(fd, SIOCGIFNETMASK, (caddr_t) ifr) < 0)
      continue;

    netmask = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr;

    /*
     * Add interface to local network list
     */
    al = ALLOC(struct addrlist);
    al->ip_addr = address;
    al->ip_mask = netmask;
    al->ip_next = localnets;
    localnets = al;

    /*
     * Figure out the subnet's network address
     */
    subnet = address & netmask;

#ifdef IN_CLASSA
    subnet = htonl(subnet);

    if (IN_CLASSA(subnet)) {
      mask = IN_CLASSA_NET;
      subnetshift = 8;
    } else if (IN_CLASSB(subnet)) {
      mask = IN_CLASSB_NET;
      subnetshift = 8;
    } else {
      mask = IN_CLASSC_NET;
      subnetshift = 4;
    }

    /*
     * If there are more bits than the standard mask
     * would suggest, subnets must be in use.
     * Guess at the subnet mask, assuming reasonable
     * width subnet fields.
     * XXX: Or-in at least 1 byte's worth of 1s to make
     * sure the top bits remain set.
     */
    while (subnet & ~mask)
      mask = (mask >> subnetshift) | 0xff000000;

    net = subnet & mask;
    while ((mask & 1) == 0)
      mask >>= 1, net >>= 1;

    /*
     * Now get a usable name.
     * First use the network database,
     * then the host database,
     * and finally just make a dotted quad.
     */
    np = getnetbyaddr(net, AF_INET);

    /* the network address has been masked off */
    if ((subnet & 0xffffff) == 0) {
      sprintf(netNumberBuf, "%lu", C(subnet >> 24));
    } else if ((subnet & 0xffff) == 0) {
      sprintf(netNumberBuf, "%lu.%lu",
	      C(subnet >> 24), C(subnet >> 16));
    } else if ((subnet & 0xff) == 0) {
      sprintf(netNumberBuf, "%lu.%lu.%lu",
	      C(subnet >> 24), C(subnet >> 16),
	      C(subnet >> 8));
    } else {
      sprintf(netNumberBuf, "%lu.%lu.%lu.%lu",
	      C(subnet >> 24), C(subnet >> 16),
	      C(subnet >> 8), C(subnet));
    }
    if (!*number1) {
      *number1 = strdup(netNumberBuf);
    } else if (!*number2) {
      *number2 = strdup(netNumberBuf);
    } else {
      plog(XLOG_INFO, "Another unused interface discovered: netnumber %s", netNumberBuf);
    }
#else /* not IN_CLASSA */
    /* This is probably very wrong. */
    np = getnetbyaddr(subnet, AF_INET);
#endif /* not IN_CLASSA */

    if (np)
      s = np->n_name;
    else {
      subnet = address & netmask;
      hp = gethostbyaddr((char *) &subnet, 4, AF_INET);
      if (hp)
	s = (char *) hp->h_name;
      else
	s = inet_dquad(buf, subnet);
    }
    if (!*name1) {
      *name1 = strdup(s);
    } else if (!*name2) {
      *name2 = strdup(s);
    } else {
      plog(XLOG_INFO, "Another unused interface discovered: netname %s", s);
    }
  }

out:
  if (fd >= 0)
    (void) close(fd);
  if (!*name1)
    *name1 = strdup(NO_SUBNET);
  if (!*number1)
    *number1 = "0.0.0.0";
  if (!*name2)
    *name2 = strdup(NO_SUBNET);
  if (!*number2)
    *number2 = "0.0.0.0";
}


/*
 * Make a dotted quad from a 32bit IP address
 * addr is in network byte order.
 * sizeof(buf) needs to be at least 16.
 */
char *
inet_dquad(char *buf, u_long addr)
{
  addr = ntohl(addr);
  sprintf(buf, "%ld.%ld.%ld.%ld",
	  ((addr >> 24) & 0xff),
	  ((addr >> 16) & 0xff),
	  ((addr >> 8) & 0xff),
	  ((addr >> 0) & 0xff));
  return buf;
}


/*
 * Determine whether a network is on a local network
 * (addr) is in network byte order.
 */
int
islocalnet(u_long addr)
{
  addrlist *al;
#ifdef DEBUG
  char buf[16];
#endif /* DEBUG */

  for (al = localnets; al; al = al->ip_next)
    if (((addr ^ al->ip_addr) & al->ip_mask) == 0)
      return TRUE;

#ifdef DEBUG
    plog(XLOG_INFO, "%s is on a remote network", inet_dquad(buf, addr));
#endif /* DEBUG */

  return FALSE;
}