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This patch fixes a crash that may occur when the routine dev_mc_sync() deletes an address from the list it is currently going through. It saves the pointer to the next element before deleting the current one. The problem may also exist in dev_mc_unsync(). Signed-off-by: Benjamin Thery <benjamin.thery@bull.net> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
262 lines
6.1 KiB
C
262 lines
6.1 KiB
C
/*
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* Linux NET3: Multicast List maintenance.
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*
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* Authors:
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* Tim Kordas <tjk@nostromo.eeap.cwru.edu>
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* Richard Underwood <richard@wuzz.demon.co.uk>
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*
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* Stir fried together from the IP multicast and CAP patches above
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* Alan Cox <Alan.Cox@linux.org>
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*
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* Fixes:
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* Alan Cox : Update the device on a real delete
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* rather than any time but...
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* Alan Cox : IFF_ALLMULTI support.
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* Alan Cox : New format set_multicast_list() calls.
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* Gleb Natapov : Remove dev_mc_lock.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/bitops.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/in.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/if_ether.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/init.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/arp.h>
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/*
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* Device multicast list maintenance.
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*
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* This is used both by IP and by the user level maintenance functions.
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* Unlike BSD we maintain a usage count on a given multicast address so
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* that a casual user application can add/delete multicasts used by
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* protocols without doing damage to the protocols when it deletes the
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* entries. It also helps IP as it tracks overlapping maps.
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*
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* Device mc lists are changed by bh at least if IPv6 is enabled,
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* so that it must be bh protected.
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*
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* We block accesses to device mc filters with netif_tx_lock.
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*/
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/*
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* Delete a device level multicast
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*/
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int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
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{
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int err;
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netif_tx_lock_bh(dev);
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err = __dev_addr_delete(&dev->mc_list, &dev->mc_count,
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addr, alen, glbl);
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if (!err) {
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/*
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* We have altered the list, so the card
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* loaded filter is now wrong. Fix it
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*/
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__dev_set_rx_mode(dev);
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}
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netif_tx_unlock_bh(dev);
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return err;
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}
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/*
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* Add a device level multicast
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*/
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int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
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{
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int err;
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netif_tx_lock_bh(dev);
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err = __dev_addr_add(&dev->mc_list, &dev->mc_count, addr, alen, glbl);
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if (!err)
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__dev_set_rx_mode(dev);
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netif_tx_unlock_bh(dev);
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return err;
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}
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/**
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* dev_mc_sync - Synchronize device's multicast list to another device
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* @to: destination device
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* @from: source device
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*
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* Add newly added addresses to the destination device and release
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* addresses that have no users left. The source device must be
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* locked by netif_tx_lock_bh.
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*
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* This function is intended to be called from the dev->set_multicast_list
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* function of layered software devices.
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*/
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int dev_mc_sync(struct net_device *to, struct net_device *from)
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{
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struct dev_addr_list *da, *next;
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int err = 0;
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netif_tx_lock_bh(to);
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da = from->mc_list;
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while (da != NULL) {
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next = da->next;
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if (!da->da_synced) {
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err = __dev_addr_add(&to->mc_list, &to->mc_count,
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da->da_addr, da->da_addrlen, 0);
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if (err < 0)
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break;
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da->da_synced = 1;
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da->da_users++;
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} else if (da->da_users == 1) {
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__dev_addr_delete(&to->mc_list, &to->mc_count,
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da->da_addr, da->da_addrlen, 0);
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__dev_addr_delete(&from->mc_list, &from->mc_count,
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da->da_addr, da->da_addrlen, 0);
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}
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da = next;
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}
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if (!err)
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__dev_set_rx_mode(to);
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netif_tx_unlock_bh(to);
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return err;
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}
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EXPORT_SYMBOL(dev_mc_sync);
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/**
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* dev_mc_unsync - Remove synchronized addresses from the destination
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* device
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* @to: destination device
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* @from: source device
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*
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* Remove all addresses that were added to the destination device by
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* dev_mc_sync(). This function is intended to be called from the
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* dev->stop function of layered software devices.
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*/
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void dev_mc_unsync(struct net_device *to, struct net_device *from)
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{
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struct dev_addr_list *da, *next;
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netif_tx_lock_bh(from);
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netif_tx_lock_bh(to);
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da = from->mc_list;
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while (da != NULL) {
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next = da->next;
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if (!da->da_synced)
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continue;
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__dev_addr_delete(&to->mc_list, &to->mc_count,
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da->da_addr, da->da_addrlen, 0);
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da->da_synced = 0;
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__dev_addr_delete(&from->mc_list, &from->mc_count,
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da->da_addr, da->da_addrlen, 0);
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da = next;
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}
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__dev_set_rx_mode(to);
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netif_tx_unlock_bh(to);
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netif_tx_unlock_bh(from);
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}
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EXPORT_SYMBOL(dev_mc_unsync);
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#ifdef CONFIG_PROC_FS
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static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
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{
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struct net_device *dev;
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loff_t off = 0;
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read_lock(&dev_base_lock);
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for_each_netdev(dev) {
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if (off++ == *pos)
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return dev;
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}
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return NULL;
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}
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static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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{
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++*pos;
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return next_net_device((struct net_device *)v);
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}
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static void dev_mc_seq_stop(struct seq_file *seq, void *v)
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{
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read_unlock(&dev_base_lock);
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}
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static int dev_mc_seq_show(struct seq_file *seq, void *v)
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{
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struct dev_addr_list *m;
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struct net_device *dev = v;
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netif_tx_lock_bh(dev);
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for (m = dev->mc_list; m; m = m->next) {
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int i;
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seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
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dev->name, m->dmi_users, m->dmi_gusers);
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for (i = 0; i < m->dmi_addrlen; i++)
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seq_printf(seq, "%02x", m->dmi_addr[i]);
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seq_putc(seq, '\n');
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}
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netif_tx_unlock_bh(dev);
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return 0;
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}
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static const struct seq_operations dev_mc_seq_ops = {
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.start = dev_mc_seq_start,
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.next = dev_mc_seq_next,
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.stop = dev_mc_seq_stop,
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.show = dev_mc_seq_show,
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};
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static int dev_mc_seq_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &dev_mc_seq_ops);
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}
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static const struct file_operations dev_mc_seq_fops = {
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.owner = THIS_MODULE,
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.open = dev_mc_seq_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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#endif
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void __init dev_mcast_init(void)
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{
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proc_net_fops_create("dev_mcast", 0, &dev_mc_seq_fops);
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}
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EXPORT_SYMBOL(dev_mc_add);
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EXPORT_SYMBOL(dev_mc_delete);
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