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config.c revision 1.5 
      1 /*	$NetBSD: config.c,v 1.5 1995/10/09 03:51:37 thorpej Exp $	*/
      2 
      3 /*
      4  * The mrouted program is covered by the license in the accompanying file
      5  * named "LICENSE".  Use of the mrouted program represents acceptance of
      6  * the terms and conditions listed in that file.
      7  *
      8  * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
      9  * Leland Stanford Junior University.
     10  */
     11 
     12 
     13 #include "defs.h"
     14 
     15 
     16 /*
     17  * Query the kernel to find network interfaces that are multicast-capable
     18  * and install them in the uvifs array.
     19  */
     20 void config_vifs_from_kernel()
     21 {
     22     struct ifreq ifbuf[32];
     23     struct ifreq *ifrp, *ifend;
     24     struct ifconf ifc;
     25     register struct uvif *v;
     26     register vifi_t vifi;
     27     int n;
     28     u_int32_t addr, mask, subnet;
     29     short flags;
     30 
     31     ifc.ifc_buf = (char *)ifbuf;
     32     ifc.ifc_len = sizeof(ifbuf);
     33     if (ioctl(udp_socket, SIOCGIFCONF, (char *)&ifc) < 0)
     34 	log(LOG_ERR, errno, "ioctl SIOCGIFCONF");
     35 
     36     ifrp = (struct ifreq *)ifbuf;
     37     ifend = (struct ifreq *)((char *)ifbuf + ifc.ifc_len);
     38     /*
     39      * Loop through all of the interfaces.
     40      */
     41     for (; ifrp < ifend; ifrp = (struct ifreq *)((char *)ifrp + n)) {
     42 	struct ifreq ifr;
     43 #if BSD >= 199006
     44 	n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
     45 	if (n < sizeof(*ifrp))
     46 	    n = sizeof(*ifrp);
     47 #else
     48 	n = sizeof(*ifrp);
     49 #endif
     50 	/*
     51 	 * Ignore any interface for an address family other than IP.
     52 	 */
     53 	if (ifrp->ifr_addr.sa_family != AF_INET)
     54 	    continue;
     55 
     56 	addr = ((struct sockaddr_in *)&ifrp->ifr_addr)->sin_addr.s_addr;
     57 
     58 	/*
     59 	 * Need a template to preserve address info that is
     60 	 * used below to locate the next entry.  (Otherwise,
     61 	 * SIOCGIFFLAGS stomps over it because the requests
     62 	 * are returned in a union.)
     63 	 */
     64 	bcopy(ifrp->ifr_name, ifr.ifr_name, sizeof(ifr.ifr_name));
     65 
     66 	/*
     67 	 * Ignore loopback interfaces and interfaces that do not support
     68 	 * multicast.
     69 	 */
     70 	if (ioctl(udp_socket, SIOCGIFFLAGS, (char *)&ifr) < 0)
     71 	    log(LOG_ERR, errno, "ioctl SIOCGIFFLAGS for %s", ifr.ifr_name);
     72 	flags = ifr.ifr_flags;
     73 	if ((flags & (IFF_LOOPBACK|IFF_MULTICAST)) != IFF_MULTICAST) continue;
     74 
     75 	/*
     76 	 * Ignore any interface whose address and mask do not define a
     77 	 * valid subnet number, or whose address is of the form {subnet,0}
     78 	 * or {subnet,-1}.
     79 	 */
     80 	if (ioctl(udp_socket, SIOCGIFNETMASK, (char *)&ifr) < 0)
     81 	    log(LOG_ERR, errno, "ioctl SIOCGIFNETMASK for %s", ifr.ifr_name);
     82 	mask = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
     83 	subnet = addr & mask;
     84 	if (!inet_valid_subnet(subnet, mask) ||
     85 	    addr == subnet ||
     86 	    addr == (subnet | ~mask)) {
     87 	    log(LOG_WARNING, 0,
     88 		"ignoring %s, has invalid address (%s) and/or mask (%s)",
     89 		ifr.ifr_name, inet_fmt(addr, s1), inet_fmt(mask, s2));
     90 	    continue;
     91 	}
     92 
     93 	/*
     94 	 * Ignore any interface that is connected to the same subnet as
     95 	 * one already installed in the uvifs array.
     96 	 */
     97 	for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
     98 	    if ((addr & v->uv_subnetmask) == v->uv_subnet ||
     99 		(v->uv_subnet & mask) == subnet) {
    100 		log(LOG_WARNING, 0, "ignoring %s, same subnet as %s",
    101 					ifr.ifr_name, v->uv_name);
    102 		break;
    103 	    }
    104 	}
    105 	if (vifi != numvifs) continue;
    106 
    107 	/*
    108 	 * If there is room in the uvifs array, install this interface.
    109 	 */
    110 	if (numvifs == MAXVIFS) {
    111 	    log(LOG_WARNING, 0, "too many vifs, ignoring %s", ifr.ifr_name);
    112 	    continue;
    113 	}
    114 	v  = &uvifs[numvifs];
    115 	v->uv_flags       = 0;
    116 	v->uv_metric      = DEFAULT_METRIC;
    117 	v->uv_rate_limit  = DEFAULT_PHY_RATE_LIMIT;
    118 	v->uv_threshold   = DEFAULT_THRESHOLD;
    119 	v->uv_lcl_addr    = addr;
    120 	v->uv_rmt_addr    = 0;
    121 	v->uv_subnet      = subnet;
    122 	v->uv_subnetmask  = mask;
    123 	v->uv_subnetbcast = subnet | ~mask;
    124 	strncpy(v->uv_name, ifr.ifr_name, IFNAMSIZ);
    125 	v->uv_groups      = NULL;
    126 	v->uv_neighbors   = NULL;
    127 	v->uv_acl         = NULL;
    128 	v->uv_addrs	  = NULL;
    129 
    130 	log(LOG_INFO,0,"installing %s (%s on subnet %s) as vif #%u - rate=%d",
    131 	    v->uv_name, inet_fmt(addr, s1), inet_fmts(subnet, mask, s2),
    132 	    numvifs, v->uv_rate_limit);
    133 
    134 	++numvifs;
    135 
    136 	/*
    137 	 * If the interface is not yet up, set the vifs_down flag to
    138 	 * remind us to check again later.
    139 	 */
    140 	if (!(flags & IFF_UP)) {
    141 	    v->uv_flags |= VIFF_DOWN;
    142 	    vifs_down = TRUE;
    143 	}
    144     }
    145 }
    146