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      1 /*	$NetBSD: config.c,v 1.13 2003/05/16 22:59:50 dsl 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 #include "defs.h"
     13 #include <net/if.h>
     14 #include <ifaddrs.h>
     15 
     16 
     17 /*
     18  * Query the kernel to find network interfaces that are multicast-capable
     19  * and install them in the uvifs array.
     20  */
     21 void
     22 config_vifs_from_kernel(void)
     23 {
     24     struct ifaddrs *ifa, *ifap;
     25     struct uvif *v;
     26     vifi_t vifi;
     27     u_int32_t addr, mask, subnet;
     28     short flags;
     29 
     30     if (getifaddrs(&ifap) < 0)
     31 	logit(LOG_ERR, errno, "getifaddrs");
     32 
     33     for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
     34 	/*
     35 	 * Ignore any interface for an address family other than IP.
     36 	 */
     37 	if (ifa->ifa_addr->sa_family != AF_INET)
     38 	    continue;
     39 
     40 	addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr;
     41 
     42 	/*
     43 	 * Ignore loopback interfaces and interfaces that do not support
     44 	 * multicast.
     45 	 */
     46 	flags = ifa->ifa_flags;
     47 	if ((flags & (IFF_LOOPBACK|IFF_MULTICAST)) != IFF_MULTICAST)
     48 	    continue;
     49 
     50 	/*
     51 	 * Ignore any interface whose address and mask do not define a
     52 	 * valid subnet number, or whose address is of the form {subnet,0}
     53 	 * or {subnet,-1}.
     54 	 */
     55 	mask = ((struct sockaddr_in *)ifa->ifa_netmask)->sin_addr.s_addr;
     56 	subnet = addr & mask;
     57 	if (!inet_valid_subnet(subnet, mask) ||
     58 	    addr == subnet ||
     59 	    addr == (subnet | ~mask)) {
     60 	    logit(LOG_WARNING, 0,
     61 		"ignoring %s, has invalid address (%s) and/or mask (%s)",
     62 		ifa->ifa_name, inet_fmt(addr),
     63 		inet_fmt(mask));
     64 	    continue;
     65 	}
     66 
     67 	/*
     68 	 * Ignore any interface that is connected to the same subnet as
     69 	 * one already installed in the uvifs array.
     70 	 */
     71 	for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
     72 	    if ((addr & v->uv_subnetmask) == v->uv_subnet ||
     73 		(v->uv_subnet & mask) == subnet) {
     74 		logit(LOG_WARNING, 0, "ignoring %s, same subnet as %s",
     75 		    ifa->ifa_name, v->uv_name);
     76 		break;
     77 	    }
     78 	}
     79 	if (vifi != numvifs)
     80 	    continue;
     81 
     82 	/*
     83 	 * If there is room in the uvifs array, install this interface.
     84 	 */
     85 	if (numvifs == MAXVIFS) {
     86 	    logit(LOG_WARNING, 0, "too many vifs, ignoring %s", ifa->ifa_name);
     87 	    continue;
     88 	}
     89 	v  = &uvifs[numvifs];
     90 	v->uv_flags       = 0;
     91 	v->uv_metric      = DEFAULT_METRIC;
     92 	v->uv_rate_limit  = DEFAULT_PHY_RATE_LIMIT;
     93 	v->uv_threshold   = DEFAULT_THRESHOLD;
     94 	v->uv_lcl_addr    = addr;
     95 	v->uv_rmt_addr    = 0;
     96 	v->uv_subnet      = subnet;
     97 	v->uv_subnetmask  = mask;
     98 	v->uv_subnetbcast = subnet | ~mask;
     99 	strlcpy(v->uv_name, ifa->ifa_name, sizeof(v->uv_name));
    100 	v->uv_groups      = NULL;
    101 	v->uv_neighbors   = NULL;
    102 	v->uv_acl         = NULL;
    103 	v->uv_addrs	  = NULL;
    104 
    105 	logit(LOG_INFO,0,"installing %s (%s on subnet %s) as vif #%u - rate=%d",
    106 	    v->uv_name, inet_fmt(addr),
    107 	    inet_fmts(subnet, mask),
    108 	    numvifs, v->uv_rate_limit);
    109 
    110 	++numvifs;
    111 
    112 	/*
    113 	 * If the interface is not yet up, set the vifs_down flag to
    114 	 * remind us to check again later.
    115 	 */
    116 	if (!(flags & IFF_UP)) {
    117 	    v->uv_flags |= VIFF_DOWN;
    118 	    vifs_down = TRUE;
    119 	}
    120     }
    121 
    122     freeifaddrs(ifap);
    123 }
    124