* Re: [Bugme-new] [Bug 15342] New: max_address parameter is not taken into consideration when IPv6 addresses are created
[not found] <bug-15342-10286@http.bugzilla.kernel.org/>
@ 2010-02-22 21:08 ` Andrew Morton
2010-02-22 22:27 ` [PATCH] IPv6: better document max_addresses parameter Brian Haley
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2010-02-22 21:08 UTC (permalink / raw)
To: netdev; +Cc: bugzilla-daemon, bugme-daemon, nedyalkor
(switched to email. Please respond via emailed reply-to-all, not via the
bugzilla web interface).
On Wed, 17 Feb 2010 14:12:28 GMT bugzilla-daemon@bugzilla.kernel.org wrote:
> http://bugzilla.kernel.org/show_bug.cgi?id=15342
>
> Summary: max_address parameter is not taken into consideration
> when IPv6 addresses are created
> Product: Networking
> Version: 2.5
> Kernel Version: 2.6.32.5
> Platform: All
> OS/Version: Linux
> Tree: Mainline
> Status: NEW
> Severity: low
> Priority: P1
> Component: IPV6
> AssignedTo: yoshfuji@linux-ipv6.org
> ReportedBy: nedyalkor@gmail.com
> Regression: No
>
>
> >From ip-sysctl.txt file in kernel documentation I can see following description
> for max_addresses:
> max_addresses - INTEGER
> Number of maximum addresses per interface. 0 disables limitation.
> It is recommended not set too large value (or 0) because it would
> be too easy way to crash kernel to allow to create too much of
> autoconfigured addresses.
> Default: 16
>
> On my machine all parameters are set to default value 16:
> # sysctl -a|grep max_addresses
> net.ipv6.conf.all.max_addresses = 16
> net.ipv6.conf.default.max_addresses = 16
> net.ipv6.conf.lo.max_addresses = 16
> net.ipv6.conf.eth0.max_addresses = 16
>
> To my understanding I should not be able to create more than 16 IP addresses,
> but in fact I am able do it:
>
> # for i in `seq 1 16`; do ip addr add fec0::$i/64 dev eth0; done
> # ip addr add fec0::17/64 dev eth0
> # ip -6 addr
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436
> inet6 ::1/128 scope host
> valid_lft forever preferred_lft forever
> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
> inet6 fec0::17/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::16/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::15/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::14/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::13/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::12/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::11/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::10/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::9/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::8/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::7/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::6/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::5/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::4/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::3/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::2/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fec0::1/64 scope site
> valid_lft forever preferred_lft forever
> inet6 fe80::223:aeff:fe77:44ba/64 scope link
> valid_lft forever preferred_lft forever
>
>
> If this parameter applies only for auto-configured IP addressed, please state
> it more clearly in docs or rename the parameter to show that it refers to
> auto-configuration.
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] IPv6: better document max_addresses parameter
2010-02-22 21:08 ` [Bugme-new] [Bug 15342] New: max_address parameter is not taken into consideration when IPv6 addresses are created Andrew Morton
@ 2010-02-22 22:27 ` Brian Haley
2010-02-23 9:25 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Brian Haley @ 2010-02-22 22:27 UTC (permalink / raw)
To: nedyalkor; +Cc: Andrew Morton, netdev, bugzilla-daemon, bugme-daemon
Andrew Morton wrote:
>> >From ip-sysctl.txt file in kernel documentation I can see following description
>> for max_addresses:
>> max_addresses - INTEGER
>> Number of maximum addresses per interface. 0 disables limitation.
>> It is recommended not set too large value (or 0) because it would
>> be too easy way to crash kernel to allow to create too much of
>> autoconfigured addresses.
^^^^^^^^^^^^^^
>> If this parameter applies only for auto-configured IP addressed, please state
>> it more clearly in docs or rename the parameter to show that it refers to
>> auto-configuration.
It did mention autoconfigured in the text, but the below makes it more obvious.
More clearly document IPv6 max_addresses parameter.
Signed-off-by: Brian Haley <brian.haley@hp.com>
---
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 2571a62..8b72c88 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1126,10 +1126,10 @@ regen_max_retry - INTEGER
Default: 5
max_addresses - INTEGER
- Number of maximum addresses per interface. 0 disables limitation.
- It is recommended not set too large value (or 0) because it would
- be too easy way to crash kernel to allow to create too much of
- autoconfigured addresses.
+ Maximum number of autoconfigured addresses per interface. Setting
+ to zero disables the limitation. It is not recommended to set this
+ value too large (or to zero) because it would be an easy way to
+ crash the kernel by allowing too many addresses to be created.
Default: 16
disable_ipv6 - BOOLEAN
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] IPv6: better document max_addresses parameter
2010-02-22 22:27 ` [PATCH] IPv6: better document max_addresses parameter Brian Haley
@ 2010-02-23 9:25 ` David Miller
0 siblings, 0 replies; 3+ messages in thread
From: David Miller @ 2010-02-23 9:25 UTC (permalink / raw)
To: brian.haley; +Cc: nedyalkor, akpm, netdev, bugzilla-daemon, bugme-daemon
From: Brian Haley <brian.haley@hp.com>
Date: Mon, 22 Feb 2010 17:27:21 -0500
> Andrew Morton wrote:
>>> >From ip-sysctl.txt file in kernel documentation I can see following description
>>> for max_addresses:
>>> max_addresses - INTEGER
>>> Number of maximum addresses per interface. 0 disables limitation.
>>> It is recommended not set too large value (or 0) because it would
>>> be too easy way to crash kernel to allow to create too much of
>>> autoconfigured addresses.
> ^^^^^^^^^^^^^^
>
>>> If this parameter applies only for auto-configured IP addressed, please state
>>> it more clearly in docs or rename the parameter to show that it refers to
>>> auto-configuration.
>
> It did mention autoconfigured in the text, but the below makes it more obvious.
>
>
> More clearly document IPv6 max_addresses parameter.
>
> Signed-off-by: Brian Haley <brian.haley@hp.com>
Applied.
^ permalink raw reply [flat|nested] 3+ messages in thread
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[not found] <bug-15342-10286@http.bugzilla.kernel.org/>
2010-02-22 21:08 ` [Bugme-new] [Bug 15342] New: max_address parameter is not taken into consideration when IPv6 addresses are created Andrew Morton
2010-02-22 22:27 ` [PATCH] IPv6: better document max_addresses parameter Brian Haley
2010-02-23 9:25 ` David Miller
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