config.c revision 1.2 
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 */
20void
21config_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