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config.c revision 1.6 
      1 /*	$NetBSD: config.c,v 1.6 1995/12/10 10:06:58 mycroft 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
     21 config_vifs_from_kernel()
     22 {
     23     struct ifreq ifbuf[32];
     24     struct ifreq *ifrp, *ifend;
     25     struct ifconf ifc;
     26     register struct uvif *v;
     27     register vifi_t vifi;
     28     int n;
     29     u_int32_t addr, mask, subnet;
     30     short flags;
     31 
     32     ifc.ifc_buf = (char *)ifbuf;
     33     ifc.ifc_len = sizeof(ifbuf);
     34     if (ioctl(udp_socket, SIOCGIFCONF, (char *)&ifc) < 0)
     35 	log(LOG_ERR, errno, "ioctl SIOCGIFCONF");
     36 
     37     ifrp = (struct ifreq *)ifbuf;
     38     ifend = (struct ifreq *)((char *)ifbuf + ifc.ifc_len);
     39     /*
     40      * Loop through all of the interfaces.
     41      */
     42     for (; ifrp < ifend; ifrp = (struct ifreq *)((char *)ifrp + n)) {
     43 	struct ifreq ifr;
     44 #if BSD >= 199006
     45 	n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
     46 	if (n < sizeof(*ifrp))
     47 	    n = sizeof(*ifrp);
     48 #else
     49 	n = sizeof(*ifrp);
     50 #endif
     51 	/*
     52 	 * Ignore any interface for an address family other than IP.
     53 	 */
     54 	if (ifrp->ifr_addr.sa_family != AF_INET)
     55 	    continue;
     56 
     57 	addr = ((struct sockaddr_in *)&ifrp->ifr_addr)->sin_addr.s_addr;
     58 
     59 	/*
     60 	 * Need a template to preserve address info that is
     61 	 * used below to locate the next entry.  (Otherwise,
     62 	 * SIOCGIFFLAGS stomps over it because the requests
     63 	 * are returned in a union.)
     64 	 */
     65 	bcopy(ifrp->ifr_name, ifr.ifr_name, sizeof(ifr.ifr_name));
     66 
     67 	/*
     68 	 * Ignore loopback interfaces and interfaces that do not support
     69 	 * multicast.
     70 	 */
     71 	if (ioctl(udp_socket, SIOCGIFFLAGS, (char *)&ifr) < 0)
     72 	    log(LOG_ERR, errno, "ioctl SIOCGIFFLAGS for %s", ifr.ifr_name);
     73 	flags = ifr.ifr_flags;
     74 	if ((flags & (IFF_LOOPBACK|IFF_MULTICAST)) != IFF_MULTICAST) continue;
     75 
     76 	/*
     77 	 * Ignore any interface whose address and mask do not define a
     78 	 * valid subnet number, or whose address is of the form {subnet,0}
     79 	 * or {subnet,-1}.
     80 	 */
     81 	if (ioctl(udp_socket, SIOCGIFNETMASK, (char *)&ifr) < 0)
     82 	    log(LOG_ERR, errno, "ioctl SIOCGIFNETMASK for %s", ifr.ifr_name);
     83 	mask = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
     84 	subnet = addr & mask;
     85 	if (!inet_valid_subnet(subnet, mask) ||
     86 	    addr == subnet ||
     87 	    addr == (subnet | ~mask)) {
     88 	    log(LOG_WARNING, 0,
     89 		"ignoring %s, has invalid address (%s) and/or mask (%s)",
     90 		ifr.ifr_name, inet_fmt(addr, s1), inet_fmt(mask, s2));
     91 	    continue;
     92 	}
     93 
     94 	/*
     95 	 * Ignore any interface that is connected to the same subnet as
     96 	 * one already installed in the uvifs array.
     97 	 */
     98 	for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
     99 	    if ((addr & v->uv_subnetmask) == v->uv_subnet ||
    100 		(v->uv_subnet & mask) == subnet) {
    101 		log(LOG_WARNING, 0, "ignoring %s, same subnet as %s",
    102 					ifr.ifr_name, v->uv_name);
    103 		break;
    104 	    }
    105 	}
    106 	if (vifi != numvifs) continue;
    107 
    108 	/*
    109 	 * If there is room in the uvifs array, install this interface.
    110 	 */
    111 	if (numvifs == MAXVIFS) {
    112 	    log(LOG_WARNING, 0, "too many vifs, ignoring %s", ifr.ifr_name);
    113 	    continue;
    114 	}
    115 	v  = &uvifs[numvifs];
    116 	v->uv_flags       = 0;
    117 	v->uv_metric      = DEFAULT_METRIC;
    118 	v->uv_rate_limit  = DEFAULT_PHY_RATE_LIMIT;
    119 	v->uv_threshold   = DEFAULT_THRESHOLD;
    120 	v->uv_lcl_addr    = addr;
    121 	v->uv_rmt_addr    = 0;
    122 	v->uv_subnet      = subnet;
    123 	v->uv_subnetmask  = mask;
    124 	v->uv_subnetbcast = subnet | ~mask;
    125 	strncpy(v->uv_name, ifr.ifr_name, IFNAMSIZ);
    126 	v->uv_groups      = NULL;
    127 	v->uv_neighbors   = NULL;
    128 	v->uv_acl         = NULL;
    129 	v->uv_addrs	  = NULL;
    130 
    131 	log(LOG_INFO,0,"installing %s (%s on subnet %s) as vif #%u - rate=%d",
    132 	    v->uv_name, inet_fmt(addr, s1), inet_fmts(subnet, mask, s2),
    133 	    numvifs, v->uv_rate_limit);
    134 
    135 	++numvifs;
    136 
    137 	/*
    138 	 * If the interface is not yet up, set the vifs_down flag to
    139 	 * remind us to check again later.
    140 	 */
    141 	if (!(flags & IFF_UP)) {
    142 	    v->uv_flags |= VIFF_DOWN;
    143 	    vifs_down = TRUE;
    144 	}
    145     }
    146 }
    147