File: /usr/src/linux/net/core/dev_mcast.c
1 /*
2 * Linux NET3: Multicast List maintenance.
3 *
4 * Authors:
5 * Tim Kordas <tjk@nostromo.eeap.cwru.edu>
6 * Richard Underwood <richard@wuzz.demon.co.uk>
7 *
8 * Stir fried together from the IP multicast and CAP patches above
9 * Alan Cox <Alan.Cox@linux.org>
10 *
11 * Fixes:
12 * Alan Cox : Update the device on a real delete
13 * rather than any time but...
14 * Alan Cox : IFF_ALLMULTI support.
15 * Alan Cox : New format set_multicast_list() calls.
16 * Gleb Natapov : Remove dev_mc_lock.
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24 #include <linux/config.h>
25 #include <asm/uaccess.h>
26 #include <asm/system.h>
27 #include <asm/bitops.h>
28 #include <linux/types.h>
29 #include <linux/kernel.h>
30 #include <linux/sched.h>
31 #include <linux/string.h>
32 #include <linux/mm.h>
33 #include <linux/socket.h>
34 #include <linux/sockios.h>
35 #include <linux/in.h>
36 #include <linux/errno.h>
37 #include <linux/interrupt.h>
38 #include <linux/if_ether.h>
39 #include <linux/inet.h>
40 #include <linux/netdevice.h>
41 #include <linux/etherdevice.h>
42 #include <linux/proc_fs.h>
43 #include <linux/init.h>
44 #include <net/ip.h>
45 #include <net/route.h>
46 #include <linux/skbuff.h>
47 #include <net/sock.h>
48 #include <net/arp.h>
49
50
51 /*
52 * Device multicast list maintenance.
53 *
54 * This is used both by IP and by the user level maintenance functions.
55 * Unlike BSD we maintain a usage count on a given multicast address so
56 * that a casual user application can add/delete multicasts used by
57 * protocols without doing damage to the protocols when it deletes the
58 * entries. It also helps IP as it tracks overlapping maps.
59 *
60 * Device mc lists are changed by bh at least if IPv6 is enabled,
61 * so that it must be bh protected.
62 *
63 * We block accesses to device mc filters with dev->xmit_lock.
64 */
65
66 /*
67 * Update the multicast list into the physical NIC controller.
68 */
69
70 static void __dev_mc_upload(struct net_device *dev)
71 {
72 /* Don't do anything till we up the interface
73 * [dev_open will call this function so the list will
74 * stay sane]
75 */
76
77 if (!(dev->flags&IFF_UP))
78 return;
79
80 /*
81 * Devices with no set multicast or which have been
82 * detached don't get set.
83 */
84
85 if (dev->set_multicast_list == NULL ||
86 !netif_device_present(dev))
87 return;
88
89 dev->set_multicast_list(dev);
90 }
91
92 void dev_mc_upload(struct net_device *dev)
93 {
94 spin_lock_bh(&dev->xmit_lock);
95 __dev_mc_upload(dev);
96 spin_unlock_bh(&dev->xmit_lock);
97 }
98
99 /*
100 * Delete a device level multicast
101 */
102
103 int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
104 {
105 int err = 0;
106 struct dev_mc_list *dmi, **dmip;
107
108 spin_lock_bh(&dev->xmit_lock);
109
110 for (dmip = &dev->mc_list; (dmi = *dmip) != NULL; dmip = &dmi->next) {
111 /*
112 * Find the entry we want to delete. The device could
113 * have variable length entries so check these too.
114 */
115 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
116 alen == dmi->dmi_addrlen) {
117 if (glbl) {
118 int old_glbl = dmi->dmi_gusers;
119 dmi->dmi_gusers = 0;
120 if (old_glbl == 0)
121 break;
122 }
123 if (--dmi->dmi_users)
124 goto done;
125
126 /*
127 * Last user. So delete the entry.
128 */
129 *dmip = dmi->next;
130 dev->mc_count--;
131
132 kfree(dmi);
133
134 /*
135 * We have altered the list, so the card
136 * loaded filter is now wrong. Fix it
137 */
138 __dev_mc_upload(dev);
139
140 spin_unlock_bh(&dev->xmit_lock);
141 return 0;
142 }
143 }
144 err = -ENOENT;
145 done:
146 spin_unlock_bh(&dev->xmit_lock);
147 return err;
148 }
149
150 /*
151 * Add a device level multicast
152 */
153
154 int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
155 {
156 int err = 0;
157 struct dev_mc_list *dmi, *dmi1;
158
159 dmi1 = (struct dev_mc_list *)kmalloc(sizeof(*dmi), GFP_ATOMIC);
160
161 spin_lock_bh(&dev->xmit_lock);
162 for (dmi = dev->mc_list; dmi != NULL; dmi = dmi->next) {
163 if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
164 dmi->dmi_addrlen == alen) {
165 if (glbl) {
166 int old_glbl = dmi->dmi_gusers;
167 dmi->dmi_gusers = 1;
168 if (old_glbl)
169 goto done;
170 }
171 dmi->dmi_users++;
172 goto done;
173 }
174 }
175
176 if ((dmi = dmi1) == NULL) {
177 spin_unlock_bh(&dev->xmit_lock);
178 return -ENOMEM;
179 }
180 memcpy(dmi->dmi_addr, addr, alen);
181 dmi->dmi_addrlen = alen;
182 dmi->next = dev->mc_list;
183 dmi->dmi_users = 1;
184 dmi->dmi_gusers = glbl ? 1 : 0;
185 dev->mc_list = dmi;
186 dev->mc_count++;
187
188 __dev_mc_upload(dev);
189
190 spin_unlock_bh(&dev->xmit_lock);
191 return 0;
192
193 done:
194 spin_unlock_bh(&dev->xmit_lock);
195 if (dmi1)
196 kfree(dmi1);
197 return err;
198 }
199
200 /*
201 * Discard multicast list when a device is downed
202 */
203
204 void dev_mc_discard(struct net_device *dev)
205 {
206 spin_lock_bh(&dev->xmit_lock);
207
208 while (dev->mc_list != NULL) {
209 struct dev_mc_list *tmp = dev->mc_list;
210 dev->mc_list = tmp->next;
211 if (tmp->dmi_users > tmp->dmi_gusers)
212 printk("dev_mc_discard: multicast leakage! dmi_users=%d\n", tmp->dmi_users);
213 kfree(tmp);
214 }
215 dev->mc_count = 0;
216
217 spin_unlock_bh(&dev->xmit_lock);
218 }
219
220 #ifdef CONFIG_PROC_FS
221 static int dev_mc_read_proc(char *buffer, char **start, off_t offset,
222 int length, int *eof, void *data)
223 {
224 off_t pos = 0, begin = 0;
225 struct dev_mc_list *m;
226 int len = 0;
227 struct net_device *dev;
228
229 read_lock(&dev_base_lock);
230 for (dev = dev_base; dev; dev = dev->next) {
231 spin_lock_bh(&dev->xmit_lock);
232 for (m = dev->mc_list; m; m = m->next) {
233 int i;
234
235 len += sprintf(buffer+len,"%-4d %-15s %-5d %-5d ", dev->ifindex,
236 dev->name, m->dmi_users, m->dmi_gusers);
237
238 for (i = 0; i < m->dmi_addrlen; i++)
239 len += sprintf(buffer+len, "%02x", m->dmi_addr[i]);
240
241 len += sprintf(buffer+len, "\n");
242
243 pos = begin + len;
244 if (pos < offset) {
245 len = 0;
246 begin = pos;
247 }
248 if (pos > offset + length) {
249 spin_unlock_bh(&dev->xmit_lock);
250 goto done;
251 }
252 }
253 spin_unlock_bh(&dev->xmit_lock);
254 }
255 *eof = 1;
256
257 done:
258 read_unlock(&dev_base_lock);
259 *start = buffer + (offset - begin);
260 len -= (offset - begin);
261 if (len > length)
262 len = length;
263 if (len < 0)
264 len = 0;
265 return len;
266 }
267 #endif
268
269 void __init dev_mcast_init(void)
270 {
271 #ifdef CONFIG_PROC_FS
272 create_proc_read_entry("net/dev_mcast", 0, 0, dev_mc_read_proc, NULL);
273 #endif
274 }
275
276