![Pavel Emelyanov](/assets/img/avatar_default.png)
With the net namespaces many code leaved the __init section, thus making the kernel occupy more memory than it did before. Since we have a config option that prohibits the namespace creation, the functions that initialize/finalize some netns stuff are simply not needed and can be freed after the boot. Currently, this is almost not noticeable, since few calls are no longer in __init, but when the namespaces will be merged it will be possible to free more code. I propose to use the __net_init, __net_exit and __net_initdata "attributes" for functions/variables that are not used if the CONFIG_NET_NS is not set to save more space in memory. The exiting functions cannot just reside in the __exit section, as noticed by David, since the init section will have references on it and the compilation will fail due to modpost checks. These references can exist, since the init namespace never dies and the exit callbacks are never called. So I introduce the __exit_refok attribute just like it is already done with the __init_refok. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
300 lines
6.9 KiB
C
300 lines
6.9 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/net_namespace.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 *net = seq->private;
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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(net, 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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struct seq_file *seq;
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int res;
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res = seq_open(file, &dev_mc_seq_ops);
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if (!res) {
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seq = file->private_data;
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seq->private = get_proc_net(inode);
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if (!seq->private) {
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seq_release(inode, file);
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res = -ENXIO;
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}
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}
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return res;
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}
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static int dev_mc_seq_release(struct inode *inode, struct file *file)
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{
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struct seq_file *seq = file->private_data;
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struct net *net = seq->private;
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put_net(net);
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return seq_release(inode, file);
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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 = dev_mc_seq_release,
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};
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#endif
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static int __net_init dev_mc_net_init(struct net *net)
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{
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if (!proc_net_fops_create(net, "dev_mcast", 0, &dev_mc_seq_fops))
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return -ENOMEM;
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return 0;
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}
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static void __net_exit dev_mc_net_exit(struct net *net)
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{
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proc_net_remove(net, "dev_mcast");
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}
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static struct pernet_operations __net_initdata dev_mc_net_ops = {
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.init = dev_mc_net_init,
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.exit = dev_mc_net_exit,
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};
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void __init dev_mcast_init(void)
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{
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register_pernet_subsys(&dev_mc_net_ops);
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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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