forked from luck/tmp_suning_uos_patched
077130c0cf
The problem: proc_net files remember which network namespace the are against but do not remember hold a reference count (as that would pin the network namespace). So we currently have a small window where the reference count on a network namespace may be incremented when opening a /proc file when it has already gone to zero. To fix this introduce maybe_get_net and get_proc_net. maybe_get_net increments the network namespace reference count only if it is greater then zero, ensuring we don't increment a reference count after it has gone to zero. get_proc_net handles all of the magic to go from a proc inode to the network namespace instance and call maybe_get_net on it. PROC_NET the old accessor is removed so that we don't get confused and use the wrong helper function. Then I fix up the callers to use get_proc_net and handle the case case where get_proc_net returns NULL. In that case I return -ENXIO because effectively the network namespace has already gone away so the files we are trying to access don't exist anymore. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> 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 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 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 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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