/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
  /*
   * Copyright (c) 1994, 1995, 1996, 1997, 1998
   *	The Regents of the University of California.  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.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed by the Computer Systems
   *	Engineering Group at Lawrence Berkeley Laboratory.
   * 4. Neither the name of the University nor of the Laboratory 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.
   */
  
  #ifdef HAVE_CONFIG_H
  #include <config.h>
  #endif
  
  #include <sys/param.h>
  #include <sys/ioctl.h>
  #include <sys/socket.h>
  #ifdef HAVE_SYS_SOCKIO_H
  #include <sys/sockio.h>
  #endif
  #include <sys/time.h>				/* concession to AIX */
  
  struct mbuf;		/* Squelch compiler warnings on some platforms for */
  struct rtentry;		/* declarations in <net/if.h> */
  #include <net/if.h>
  #include <netinet/in.h>
  
  #include <ctype.h>
  #include <errno.h>
  #include <memory.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  #ifdef HAVE_LIMITS_H
  #include <limits.h>
  #else
  #define INT_MAX		2147483647
  #endif
  
  #include "pcap-int.h"
  
  #ifdef HAVE_OS_PROTO_H
  #include "os-proto.h"
  #endif
  
  /*
   * This is fun.
   *
   * In older BSD systems, socket addresses were fixed-length, and
   * "sizeof (struct sockaddr)" gave the size of the structure.
   * All addresses fit within a "struct sockaddr".
   *
   * In newer BSD systems, the socket address is variable-length, and
   * there's an "sa_len" field giving the length of the structure;
   * this allows socket addresses to be longer than 2 bytes of family
   * and 14 bytes of data.
   *
   * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553
   * variant of the old BSD scheme (with "struct sockaddr_storage" rather
   * than "struct sockaddr"), and some use the new BSD scheme.
   *
   * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
   * macro that determines the size based on the address family.  Other
   * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
   * but not in the final version).
   *
   * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have
   * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the
   * address in an entry returned by SIOCGIFCONF.
   */
  #ifndef SA_LEN
  #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
  #define SA_LEN(addr)	((addr)->sa_len)
  #else /* HAVE_STRUCT_SOCKADDR_SA_LEN */
  #define SA_LEN(addr)	(sizeof (struct sockaddr))
  #endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
  #endif /* SA_LEN */
  
  /*
   * This is also fun.
   *
   * There is no ioctl that returns the amount of space required for all
   * the data that SIOCGIFCONF could return, and if a buffer is supplied
   * that's not large enough for all the data SIOCGIFCONF could return,
   * on at least some platforms it just returns the data that'd fit with
   * no indication that there wasn't enough room for all the data, much
   * less an indication of how much more room is required.
   *
   * The only way to ensure that we got all the data is to pass a buffer
   * large enough that the amount of space in the buffer *not* filled in
   * is greater than the largest possible entry.
   *
   * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption
   * that no address is more than 255 bytes (on systems where the "sa_len"
   * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the
   * case, and addresses are unlikely to be bigger than that in any case).
   */
  #define MAX_SA_LEN	255
  
  /*
   * Get a list of all interfaces that are up and that we can open.
   * Returns -1 on error, 0 otherwise.
   * The list, as returned through "alldevsp", may be null if no interfaces
   * were up and could be opened.
   *
   * This is the implementation used on platforms that have SIOCGIFCONF but
   * don't have any other mechanism for getting a list of interfaces.
   *
   * XXX - or platforms that have other, better mechanisms but for which
   * we don't yet have code to use that mechanism; I think there's a better
   * way on Linux, for example, but if that better way is "getifaddrs()",
   * we already have that.
   */
  int
  pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf,
      int (*check_usable)(const char *), get_if_flags_func get_flags_func)
  {
  	register int fd;
  	register struct ifreq *ifrp, *ifend, *ifnext;
  	size_t n;
  	struct ifconf ifc;
  	char *buf = NULL;
  	unsigned buf_size;
  #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
  	char *p, *q;
  #endif
  	struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;
  	struct sockaddr *netmask, *broadaddr, *dstaddr;
  	size_t netmask_size, broadaddr_size, dstaddr_size;
  	int ret = 0;
  
  	/*
  	 * Create a socket from which to fetch the list of interfaces.
  	 */
  	fd = socket(AF_INET, SOCK_DGRAM, 0);
  	if (fd < 0) {
  		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
  		    errno, "socket");
  		return (-1);
  	}
  
  	/*
  	 * Start with an 8K buffer, and keep growing the buffer until
  	 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"
  	 * bytes left over in the buffer or we fail to get the
  	 * interface list for some reason other than EINVAL (which is
  	 * presumed here to mean "buffer is too small").
  	 */
  	buf_size = 8192;
  	for (;;) {
  		/*
  		 * Don't let the buffer size get bigger than INT_MAX.
  		 */
  		if (buf_size > INT_MAX) {
  			(void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
  			    "interface information requires more than %u bytes",
  			    INT_MAX);
  			(void)close(fd);
  			return (-1);
  		}
  		buf = malloc(buf_size);
  		if (buf == NULL) {
  			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
  			    errno, "malloc");
  			(void)close(fd);
  			return (-1);
  		}
  
  		ifc.ifc_len = buf_size;
  		ifc.ifc_buf = buf;
  		memset(buf, 0, buf_size);
  		if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0
  		    && errno != EINVAL) {
  			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
  			    errno, "SIOCGIFCONF");
  			(void)close(fd);
  			free(buf);
  			return (-1);
  		}
  		if (ifc.ifc_len < (int)buf_size &&
  		    (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)
  			break;
  		free(buf);
  		buf_size *= 2;
  	}
  
  	ifrp = (struct ifreq *)buf;
  	ifend = (struct ifreq *)(buf + ifc.ifc_len);
  
  	for (; ifrp < ifend; ifrp = ifnext) {
  		/*
  		 * XXX - what if this isn't an IPv4 address?  Can
  		 * we still get the netmask, etc. with ioctls on
  		 * an IPv4 socket?
  		 *
  		 * The answer is probably platform-dependent, and
  		 * if the answer is "no" on more than one platform,
  		 * the way you work around it is probably platform-
  		 * dependent as well.
  		 */
  		n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);
  		if (n < sizeof(*ifrp))
  			ifnext = ifrp + 1;
  		else
  			ifnext = (struct ifreq *)((char *)ifrp + n);
  
  		/*
  		 * XXX - The 32-bit compatibility layer for Linux on IA-64
  		 * is slightly broken. It correctly converts the structures
  		 * to and from kernel land from 64 bit to 32 bit but
  		 * doesn't update ifc.ifc_len, leaving it larger than the
  		 * amount really used. This means we read off the end
  		 * of the buffer and encounter an interface with an
  		 * "empty" name. Since this is highly unlikely to ever
  		 * occur in a valid case we can just finish looking for
  		 * interfaces if we see an empty name.
  		 */
  		if (!(*ifrp->ifr_name))
  			break;
  
  		/*
  		 * Skip entries that begin with "dummy".
  		 * XXX - what are these?  Is this Linux-specific?
  		 * Are there platforms on which we shouldn't do this?
  		 */
  		if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)
  			continue;
  
  		/*
  		 * Can we capture on this device?
  		 */
  		if (!(*check_usable)(ifrp->ifr_name)) {
  			/*
  			 * No.
  			 */
  			continue;
  		}
  
  		/*
  		 * Get the flags for this interface.
  		 */
  		strncpy(ifrflags.ifr_name, ifrp->ifr_name,
  		    sizeof(ifrflags.ifr_name));
  		if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
  			if (errno == ENXIO)
  				continue;
  			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
  			    errno, "SIOCGIFFLAGS: %.*s",
  			    (int)sizeof(ifrflags.ifr_name),
  			    ifrflags.ifr_name);
  			ret = -1;
  			break;
  		}
  
  		/*
  		 * Get the netmask for this address on this interface.
  		 */
  		strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,
  		    sizeof(ifrnetmask.ifr_name));
  		memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,
  		    sizeof(ifrnetmask.ifr_addr));
  		if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {
  			if (errno == EADDRNOTAVAIL) {
  				/*
  				 * Not available.
  				 */
  				netmask = NULL;
  				netmask_size = 0;
  			} else {
  				pcap_fmt_errmsg_for_errno(errbuf,
  				    PCAP_ERRBUF_SIZE, errno,
  				    "SIOCGIFNETMASK: %.*s",
  				    (int)sizeof(ifrnetmask.ifr_name),
  				    ifrnetmask.ifr_name);
  				ret = -1;
  				break;
  			}
  		} else {
  			netmask = &ifrnetmask.ifr_addr;
  			netmask_size = SA_LEN(netmask);
  		}
  
  		/*
  		 * Get the broadcast address for this address on this
  		 * interface (if any).
  		 */
  		if (ifrflags.ifr_flags & IFF_BROADCAST) {
  			strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,
  			    sizeof(ifrbroadaddr.ifr_name));
  			memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,
  			    sizeof(ifrbroadaddr.ifr_addr));
  			if (ioctl(fd, SIOCGIFBRDADDR,
  			    (char *)&ifrbroadaddr) < 0) {
  				if (errno == EADDRNOTAVAIL) {
  					/*
  					 * Not available.
  					 */
  					broadaddr = NULL;
  					broadaddr_size = 0;
  				} else {
  					pcap_fmt_errmsg_for_errno(errbuf,
  					    PCAP_ERRBUF_SIZE, errno,
  					    "SIOCGIFBRDADDR: %.*s",
  					    (int)sizeof(ifrbroadaddr.ifr_name),
  					    ifrbroadaddr.ifr_name);
  					ret = -1;
  					break;
  				}
  			} else {
  				broadaddr = &ifrbroadaddr.ifr_broadaddr;
  				broadaddr_size = SA_LEN(broadaddr);
  			}
  		} else {
  			/*
  			 * Not a broadcast interface, so no broadcast
  			 * address.
  			 */
  			broadaddr = NULL;
  			broadaddr_size = 0;
  		}
  
  		/*
  		 * Get the destination address for this address on this
  		 * interface (if any).
  		 */
  		if (ifrflags.ifr_flags & IFF_POINTOPOINT) {
  			strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,
  			    sizeof(ifrdstaddr.ifr_name));
  			memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,
  			    sizeof(ifrdstaddr.ifr_addr));
  			if (ioctl(fd, SIOCGIFDSTADDR,
  			    (char *)&ifrdstaddr) < 0) {
  				if (errno == EADDRNOTAVAIL) {
  					/*
  					 * Not available.
  					 */
  					dstaddr = NULL;
  					dstaddr_size = 0;
  				} else {
  					pcap_fmt_errmsg_for_errno(errbuf,
  					    PCAP_ERRBUF_SIZE, errno,
  					    "SIOCGIFDSTADDR: %.*s",
  					    (int)sizeof(ifrdstaddr.ifr_name),
  					    ifrdstaddr.ifr_name);
  					ret = -1;
  					break;
  				}
  			} else {
  				dstaddr = &ifrdstaddr.ifr_dstaddr;
  				dstaddr_size = SA_LEN(dstaddr);
  			}
  		} else {
  			/*
  			 * Not a point-to-point interface, so no destination
  			 * address.
  			 */
  			dstaddr = NULL;
  			dstaddr_size = 0;
  		}
  
  #if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)
  		/*
  		 * If this entry has a colon followed by a number at
  		 * the end, it's a logical interface.  Those are just
  		 * the way you assign multiple IP addresses to a real
  		 * interface, so an entry for a logical interface should
  		 * be treated like the entry for the real interface;
  		 * we do that by stripping off the ":" and the number.
  		 */
  		p = strchr(ifrp->ifr_name, ':');
  		if (p != NULL) {
  			/*
  			 * We have a ":"; is it followed by a number?
  			 */
  			q = p + 1;
  			while (isdigit((unsigned char)*q))
  				q++;
  			if (*q == '\0') {
  				/*
  				 * All digits after the ":" until the end.
  				 * Strip off the ":" and everything after
  				 * it.
  				 */
  				*p = '\0';
  			}
  		}
  #endif
  
  		/*
  		 * Add information for this address to the list.
  		 */
  		if (add_addr_to_if(devlistp, ifrp->ifr_name,
  		    ifrflags.ifr_flags, get_flags_func,
  		    &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr),
  		    netmask, netmask_size, broadaddr, broadaddr_size,
  		    dstaddr, dstaddr_size, errbuf) < 0) {
  			ret = -1;
  			break;
  		}
  	}
  	free(buf);
  	(void)close(fd);
  
  	return (ret);
  }