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Alexey Dobriyan <adobriyan@gmail.com> writes:
> Subject: ICMP sockets destruction vs ICMP packets oops
> After icmp_sk_exit() nuked ICMP sockets, we get an interrupt.
> icmp_reply() wants ICMP socket.
>
> Steps to reproduce:
>
> launch shell in new netns
> move real NIC to netns
> setup routing
> ping -i 0
> exit from shell
>
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
> IP: [<ffffffff803fce17>] icmp_sk+0x17/0x30
> PGD 17f3cd067 PUD 17f3ce067 PMD 0
> Oops: 0000 [1] PREEMPT SMP DEBUG_PAGEALLOC
> CPU 0
> Modules linked in: usblp usbcore
> Pid: 0, comm: swapper Not tainted 2.6.26-rc6-netns-ct #4
> RIP: 0010:[<ffffffff803fce17>] [<ffffffff803fce17>] icmp_sk+0x17/0x30
> RSP: 0018:ffffffff8057fc30 EFLAGS: 00010286
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff81017c7db900
> RDX: 0000000000000034 RSI: ffff81017c7db900 RDI: ffff81017dc41800
> RBP: ffffffff8057fc40 R08: 0000000000000001 R09: 000000000000a815
> R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff8057fd28
> R13: ffffffff8057fd00 R14: ffff81017c7db938 R15: ffff81017dc41800
> FS: 0000000000000000(0000) GS:ffffffff80525000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> CR2: 0000000000000000 CR3: 000000017fcda000 CR4: 00000000000006e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Process swapper (pid: 0, threadinfo ffffffff8053a000, task ffffffff804fa4a0)
> Stack: 0000000000000000 ffff81017c7db900 ffffffff8057fcf0 ffffffff803fcfe4
> ffffffff804faa38 0000000000000246 0000000000005a40 0000000000000246
> 000000000001ffff ffff81017dd68dc0 0000000000005a40 0000000055342436
> Call Trace:
> <IRQ> [<ffffffff803fcfe4>] icmp_reply+0x44/0x1e0
> [<ffffffff803d3a0a>] ? ip_route_input+0x23a/0x1360
> [<ffffffff803fd645>] icmp_echo+0x65/0x70
> [<ffffffff803fd300>] icmp_rcv+0x180/0x1b0
> [<ffffffff803d6d84>] ip_local_deliver+0xf4/0x1f0
> [<ffffffff803d71bb>] ip_rcv+0x33b/0x650
> [<ffffffff803bb16a>] netif_receive_skb+0x27a/0x340
> [<ffffffff803be57d>] process_backlog+0x9d/0x100
> [<ffffffff803bdd4d>] net_rx_action+0x18d/0x250
> [<ffffffff80237be5>] __do_softirq+0x75/0x100
> [<ffffffff8020c97c>] call_softirq+0x1c/0x30
> [<ffffffff8020f085>] do_softirq+0x65/0xa0
> [<ffffffff80237af7>] irq_exit+0x97/0xa0
> [<ffffffff8020f198>] do_IRQ+0xa8/0x130
> [<ffffffff80212ee0>] ? mwait_idle+0x0/0x60
> [<ffffffff8020bc46>] ret_from_intr+0x0/0xf
> <EOI> [<ffffffff80212f2c>] ? mwait_idle+0x4c/0x60
> [<ffffffff80212f23>] ? mwait_idle+0x43/0x60
> [<ffffffff8020a217>] ? cpu_idle+0x57/0xa0
> [<ffffffff8040f380>] ? rest_init+0x70/0x80
> Code: 10 5b 41 5c 41 5d 41 5e c9 c3 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 53
> 48 83 ec 08 48 8b 9f 78 01 00 00 e8 2b c7 f1 ff 89 c0 <48> 8b 04 c3 48 83 c4 08
> 5b c9 c3 66 66 66 66 66 2e 0f 1f 84 00
> RIP [<ffffffff803fce17>] icmp_sk+0x17/0x30
> RSP <ffffffff8057fc30>
> CR2: 0000000000000000
> ---[ end trace ea161157b76b33e8 ]---
> Kernel panic - not syncing: Aiee, killing interrupt handler!
Receiving packets while we are cleaning up a network namespace is a
racy proposition. It is possible when the packet arrives that we have
removed some but not all of the state we need to fully process it. We
have the choice of either playing wack-a-mole with the cleanup routines
or simply dropping packets when we don't have a network namespace to
handle them.
Since the check looks inexpensive in netif_receive_skb let's just
drop the incoming packets.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Make release_net/hold_net noop for performance-hungry people. This is a debug
staff and should be used in the debug mode only.
Add check for net != NULL in hold/release calls. This will be required
later on.
[ Added minor simplifications suggested by Brian Haley. -DaveM ]
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add the elastic array of void * pointer to the struct net.
The access rules are simple:
1. register the ops with register_pernet_gen_device to get
the id of your private pointer
2. call net_assign_generic() to put the private data on the
struct net (most preferably this should be done in the
->init callback of the ops registered)
3. do not store any private reference on the net_generic array;
4. do not change this pointer while the net is alive;
5. use the net_generic() to get the pointer.
When adding a new pointer, I copy the old array, replace it
with a new one and schedule the old for kfree after an RCU
grace period.
Since the net_generic explores the net->gen array inside rcu
read section and once set the net->gen->ptr[x] pointer never
changes, this grants us a safe access to generic pointers.
Quoting Paul: "... RCU is protecting -only- the net_generic
structure that net_generic() is traversing, and the [pointer]
returned by net_generic() is protected by a reference counter
in the upper-level struct net."
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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To make some per-net generic pointers, we need some way to address
them, i.e. - IDs. This is simple IDA-based IDs generator for pernet
subsystems.
Addressing questions about potential checkpoint/restart problems:
these IDs are "lite-offsets" within the net structure and are by no
means supposed to be exported to the userspace.
Since it will be used in the nearest future by devices only (tun,
vlan, tunnels, bridge, etc), I make it resemble the functionality
of register_pernet_device().
The new ids is stored in the *id pointer _before_ calling the init
callback to make this id available in this callback.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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According to the overall struct net design, it will be
filled with DCCP-related members.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This does not look good, but there is no other choice. The compilation
without CONFIG_NET is broken and can not be fixed with ease.
After that there is no need for the following commits:
1567ca7eec7664b8be3b07755ac59dc1b1ec76cb
3edf8fa5ccf10688a9280b5cbca8ed3947c42866
2d38f9a4f8d2ebdc799f03eecf82345825495711
Revert them.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There's already some stuff on the struct net, that should better
be folded into netns_core structure. I'm making the per-proto inuse
counter be per-net also, which is also a candidate for this, so
introduce this structure and populate it a bit.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Introduce an inline net_eq() to compare two namespaces.
Without CONFIG_NET_NS, since no namespace other than &init_net
exists, it is always 1.
We do not need to convert 1) inline vs inline and
2) inline vs &init_net comparisons.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
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Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.
The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.
The proposed fix is to turn /proc/net into a symlink, which points
to /proc/self/net, which in turn shows what previously was in
/proc/net - the network-related info, from the net namespace the
appropriate task lives in.
# ls -l /proc/net
lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net
In other words - this behaves like /proc/mounts, but unlike
"mounts", "net" is not a file, but a directory.
Changes from v2:
* Fixed discrepancy of /proc/net nlink count and selinux labeling
screwup pointed out by Stephen.
To get the correct nlink count the ->getattr callback for /proc/net
is overridden to read one from the net->proc_net entry.
To make selinux still work the net->proc_net entry is initialized
properly, i.e. with the "net" name and the proc_net parent.
Selinux fixes are
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Changes from v1:
* Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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In fact all we want is per-netns set of rules, however doing that will
unnecessary complicate routines such as ipt_hook()/ipt_do_table, so
make full xt_table array per-netns.
Every user stubbed with init_net for a while.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Move static rules_ops & rules_mod_lock to the struct net, register the
pernet subsys to init them and enjoy the fact that the core rules
infrastructure works in the namespace.
Real IPv4 fib rules virtualization requires fib tables support in the
namespace and will be done seriously later in the patchset.
Acked-by: Benjamin Thery <benjamin.thery@bull.net>
Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Like the ipv4 part, this patch adds an ipv6 structure in the net
structure to aggregate the different resources to make ipv6 per
namespace.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The ipv4 will store its parameters inside this structure.
This one is empty now, but it will be eventually filled.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Recently David Miller and Herbert Xu pointed out that struct net becomes
overbloated and un-maintainable. There are two solutions:
- provide a pointer to a network subsystem definition from struct net.
This costs an additional dereferrence
- place sub-system definition into the structure itself. This will speedup
run-time access at the cost of recompilation time
The second approach looks better for us. Other sub-systems will follow.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Just move the variable on the struct net and adjust
its usage.
Others sysctls from sys.net.core table are more
difficult to virtualize (i.e. make them per-namespace),
but I'll look at them as well a bit later.
Signed-off-by: Pavel Emelyanov <xemul@oenvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Making them per-namespace is required for the following
two reasons:
First, some ctl values have a per-namespace meaning.
Second, making them writable from the sub-namespace
is an isolation hole.
So I introduce the pernet operations to create these
tables. For init_net I use the existing statically
declared tables, for sub-namespace they are duplicated
and the write bits are removed from the mode.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This is the core.
* add the ctl_table_header on the struct net;
* make the unix_sysctl_register and _unregister clone the table;
* moves calls to them into per-net init and exit callbacks;
* move the .data pointer in the proper place.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This will make all the sub-namespaces always use the
default value (10) and leave the tuning via sysctl
to the init namespace only.
Per-namespace tuning is coming.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The user interface is: register_net_sysctl_table and
unregister_net_sysctl_table. Very much like the current
interface except there is a network namespace parameter.
With this any sysctl registered with register_net_sysctl_table
will only show up to tasks in the same network namespace.
All other sysctls continue to be globally visible.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Daniel Lezcano <dlezcano@fr.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This is done by making packet_sklist_lock and packet_sklist per
network namespace and adding an additional filter condition on
received packets to ensure they came from the proper network
namespace.
Changes from v1:
- prohibit to call inet_dgram_ops.ioctl in other than init_net
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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After this patch none of the netlink callback support anything
except the initial network namespace but the rtnetlink infrastructure
now handles multiple network namespaces.
Changes from v2:
- IPv6 addrlabel processing
Changes from v1:
- no need for special rtnl_unlock handling
- fixed IPv6 ndisc
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch reverts Eric's commit 2b008b0a8e96b726c603c5e1a5a7a509b5f61e35
It diets .text & .data section of the kernel if CONFIG_NET_NS is not set.
This is safe after list operations cleanup.
Signed-of-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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When the CONFIG_NET_NS is n there's no need in refcounting
the initial net namespace. So relax this code by making a
stupid stubs for the "n" case.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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It is not safe to to place struct pernet_operations in a special section.
We need struct pernet_operations to last until we call unregister_pernet_subsys.
Which doesn't happen until module unload.
So marking struct pernet_operations is a disaster for modules in two ways.
- We discard it before we call the exit method it points to.
- Because I keep struct pernet_operations on a linked list discarding
it for compiled in code removes elements in the middle of a linked
list and does horrible things for linked insert.
So this looks safe assuming __exit_refok is not discarded
for modules.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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>
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Denis V. Lunev <den@sw.ru> noticed that the locking rules
for the network namespace list are over complicated and broken.
In particular the current register_netdev_notifier currently
does not take any lock making the for_each_net iteration racy
with network namespace creation and destruction. Oops.
The fact that we need to use for_each_net in rtnl_unlock() when
the rtnetlink support becomes per network namespace makes designing
the proper locking tricky. In addition we need to be able to call
rtnl_lock() and rtnl_unlock() when we have the net_mutex held.
After thinking about it and looking at the alternatives carefully
it looks like the simplest and most maintainable solution is
to remove net_list_mutex altogether, and to use the rtnl_mutex instead.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch makes loopback_dev per network namespace. Adding
code to create a different loopback device for each network
namespace and adding the code to free a loopback device
when a network namespace exits.
This patch modifies all users the loopback_dev so they
access it as init_net.loopback_dev, keeping all of the
code compiling and working. A later pass will be needed to
update the users to use something other than the initial network
namespace.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch allows you to create a new network namespace
using sys_clone, or sys_unshare.
As the network namespace is still experimental and under development
clone and unshare support is only made available when CONFIG_NET_NS is
selected at compile time.
As this patch introduces network namespace support into code paths
that exist when the CONFIG_NET is not selected there are a few
additions made to net_namespace.h to allow a few more functions
to be used when the networking stack is not compiled in.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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>
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When CONFIG_NET=no, init_net is unresolved because net_namespace.c
is not compiled and the include pull init_net definition.
This problem was very similar with the ipc namespace where the kernel
can be compiled with SYSV ipc out.
This patch fix that defining a macro which simply remove init_net
initialization from nsproxy namespace aggregator.
Compiled and booted on qemu-i386 with CONFIG_NET=no and CONFIG_NET=yes.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch makes most of the generic device layer network
namespace safe. This patch makes dev_base_head a
network namespace variable, and then it picks up
a few associated variables. The functions:
dev_getbyhwaddr
dev_getfirsthwbytype
dev_get_by_flags
dev_get_by_name
__dev_get_by_name
dev_get_by_index
__dev_get_by_index
dev_ioctl
dev_ethtool
dev_load
wireless_process_ioctl
were modified to take a network namespace argument, and
deal with it.
vlan_ioctl_set and brioctl_set were modified so their
hooks will receive a network namespace argument.
So basically anthing in the core of the network stack that was
affected to by the change of dev_base was modified to handle
multiple network namespaces. The rest of the network stack was
simply modified to explicitly use &init_net the initial network
namespace. This can be fixed when those components of the network
stack are modified to handle multiple network namespaces.
For now the ifindex generator is left global.
Fundametally ifindex numbers are per namespace, or else
we will have corner case problems with migration when
we get that far.
At the same time there are assumptions in the network stack
that the ifindex of a network device won't change. Making
the ifindex number global seems a good compromise until
the network stack can cope with ifindex changes when
you change namespaces, and the like.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch makes /proc/net per network namespace. It modifies the global
variables proc_net and proc_net_stat to be per network namespace.
The proc_net file helpers are modified to take a network namespace argument,
and all of their callers are fixed to pass &init_net for that argument.
This ensures that all of the /proc/net files are only visible and
usable in the initial network namespace until the code behind them
has been updated to be handle multiple network namespaces.
Making /proc/net per namespace is necessary as at least some files
in /proc/net depend upon the set of network devices which is per
network namespace, and even more files in /proc/net have contents
that are relevant to a single network namespace.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This is the basic infrastructure needed to support network
namespaces. This infrastructure is:
- Registration functions to support initializing per network
namespace data when a network namespaces is created or destroyed.
- struct net. The network namespace data structure.
This structure will grow as variables are made per network
namespace but this is the minimal starting point.
- Functions to grab a reference to the network namespace.
I provide both get/put functions that keep a network namespace
from being freed. And hold/release functions serve as weak references
and will warn if their count is not zero when the data structure
is freed. Useful for dealing with more complicated data structures
like the ipv4 route cache.
- A list of all of the network namespaces so we can iterate over them.
- A slab for the network namespace data structure allowing leaks
to be spotted.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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