[PATCH] net: tunnels - enable module autoloading

[PATCH] net: tunnels - enable module autoloading

[Tom Gundersen]

Enable the module alias hookup to allow tunnel modules to be autoloaded on demand.

This is in line with how most other netdev kinds work, and will allow userspace
to create tunnels without having CAP_SYS_MODULE.

Signed-off-by: Tom Gundersen <teg@jklm.no>
Tested-by: Susant Sahani <susant@redhat.com>
---
 net/ipv4/ipip.c       | 1 +
 net/ipv6/ip6_tunnel.c | 1 +
 net/ipv6/sit.c        | 1 +
 3 files changed, 3 insertions(+)

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 812b183..d8155cf 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -486,4 +486,5 @@ static void __exit ipip_fini(void)
 module_init(ipip_init);
 module_exit(ipip_fini);
 MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("ipip")
 MODULE_ALIAS_NETDEV("tunl0");
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index b05b609..fe61545 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -61,6 +61,7 @@
 MODULE_AUTHOR("Ville Nuorvala");
 MODULE_DESCRIPTION("IPv6 tunneling device");
 MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("ip6tnl");
 MODULE_ALIAS_NETDEV("ip6tnl0");
 
 #ifdef IP6_TNL_DEBUG
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index e5a453c..f438004 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1828,4 +1828,5 @@ xfrm_tunnel_failed:
 module_init(sit_init);
 module_exit(sit_cleanup);
 MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("sit");
 MODULE_ALIAS_NETDEV("sit0");
-- 
1.9.0

Re: [PATCH] net: tunnels - enable module autoloading

[David Miller]

From: Tom Gundersen <teg@jklm.no>
Date: Tue, 13 May 2014 10:48:28 +0200

> Enable the module alias hookup to allow tunnel modules to be autoloaded on demand.
> 
> This is in line with how most other netdev kinds work, and will allow userspace
> to create tunnels without having CAP_SYS_MODULE.
> 
> Signed-off-by: Tom Gundersen <teg@jklm.no>
> Tested-by: Susant Sahani <susant@redhat.com>

This doesn't even compile:

  CC [M]  net/ipv4/ipip.o
In file included from include/linux/module.h:17:0,
                 from net/ipv4/ipip.c:95:
include/linux/moduleparam.h:21:1: error: expected ‘,’ or ‘;’ before ‘static’
 static const char __UNIQUE_ID(name)[]       \
 ^
include/linux/module.h:86:32: note: in expansion of macro ‘__MODULE_INFO’
 #define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
                                ^
include/linux/module.h:89:30: note: in expansion of macro ‘MODULE_INFO’
 #define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias)
                              ^
include/linux/netdevice.h:3283:2: note: in expansion of macro ‘MODULE_ALIAS’
  MODULE_ALIAS("netdev-" device)
  ^
net/ipv4/ipip.c:490:1: note: in expansion of macro ‘MODULE_ALIAS_NETDEV’
 MODULE_ALIAS_NETDEV("tunl0");
 ^

[PATCH v2] net: tunnels - enable module autoloading

[Tom Gundersen]

Enable the module alias hookup to allow tunnel modules to be autoloaded on demand.

This is in line with how most other netdev kinds work, and will allow userspace
to create tunnels without having CAP_SYS_MODULE.

Signed-off-by: Tom Gundersen <teg@jklm.no>
---
v2: add ';'

Hi Dave,

I must have sent out the wrong version of this patch. Sorry for the inconvenience!

Cheers,

Tom

 net/ipv4/ipip.c       | 1 +
 net/ipv6/ip6_tunnel.c | 1 +
 net/ipv6/sit.c        | 1 +
 3 files changed, 3 insertions(+)

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 812b183..4bc508f 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -486,4 +486,5 @@ static void __exit ipip_fini(void)
 module_init(ipip_init);
 module_exit(ipip_fini);
 MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("ipip");
 MODULE_ALIAS_NETDEV("tunl0");
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index b05b609..fe61545 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -61,6 +61,7 @@
 MODULE_AUTHOR("Ville Nuorvala");
 MODULE_DESCRIPTION("IPv6 tunneling device");
 MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("ip6tnl");
 MODULE_ALIAS_NETDEV("ip6tnl0");
 
 #ifdef IP6_TNL_DEBUG
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index e5a453c..f438004 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1828,4 +1828,5 @@ xfrm_tunnel_failed:
 module_init(sit_init);
 module_exit(sit_cleanup);
 MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("sit");
 MODULE_ALIAS_NETDEV("sit0");
-- 
1.9.0

Re: [PATCH v2] net: tunnels - enable module autoloading

[David Miller]

From: Tom Gundersen <teg@jklm.no>
Date: Thu, 15 May 2014 23:21:30 +0200

> Enable the module alias hookup to allow tunnel modules to be autoloaded on demand.
> 
> This is in line with how most other netdev kinds work, and will allow userspace
> to create tunnels without having CAP_SYS_MODULE.
> 
> Signed-off-by: Tom Gundersen <teg@jklm.no>
> ---
> v2: add ';'
> 
> Hi Dave,
> 
> I must have sent out the wrong version of this patch. Sorry for the inconvenience!

Applied to net-next, although I never saw a firm conclusion in the
thread for the original patch where there was a discussion about
whether this is already possible or not.

Re: [PATCH v2] net: tunnels - enable module autoloading

[Tom Gundersen]

On Wed, May 21, 2014 at 9:47 PM, David Miller <davem@davemloft.net> wrote:
> From: Tom Gundersen <teg@jklm.no>
> Date: Thu, 15 May 2014 23:21:30 +0200
>
>> Enable the module alias hookup to allow tunnel modules to be autoloaded on demand.
>>
>> This is in line with how most other netdev kinds work, and will allow userspace
>> to create tunnels without having CAP_SYS_MODULE.
>>
>> Signed-off-by: Tom Gundersen <teg@jklm.no>
>> ---
>> v2: add ';'
>>
>> Hi Dave,
>>
>> I must have sent out the wrong version of this patch. Sorry for the inconvenience!
>
> Applied to net-next

Thanks!

> although I never saw a firm conclusion in the
> thread for the original patch where there was a discussion about
> whether this is already possible or not.

It is my understanding that this is not already possible, which is why
the MODULE_ALIAS_RTNL_LINK exists.

Would this patch be suitable for stable? While it does not fix a
regression, it appears to fix the intended behaviour of
MODULE_ALIAS_RTNL_LINK?

What I'll do in userspace is to drop CAP_SYS_MODULE and just tell
people who want tunnels to wait for a new kernel (or backport the
patch), but having it in stable would obviously make it simpler.

Cheers,

Tom

Re: [PATCH v2] net: tunnels - enable module autoloading

[David Miller]

From: Tom Gundersen <teg@jklm.no>
Date: Mon, 2 Jun 2014 20:57:02 +0200

> Would this patch be suitable for stable? While it does not fix a
> regression, it appears to fix the intended behaviour of
> MODULE_ALIAS_RTNL_LINK?

It probably is suitable... I'll queue it up, thanks.

Re: [PATCH] net: tunnels - enable module autoloading

[Stephen Hemminger]

On Tue, 13 May 2014 10:48:28 +0200
Tom Gundersen <teg@jklm.no> wrote:

> Enable the module alias hookup to allow tunnel modules to be autoloaded on demand.
> 
> This is in line with how most other netdev kinds work, and will allow userspace
> to create tunnels without having CAP_SYS_MODULE.
> 
> Signed-off-by: Tom Gundersen <teg@jklm.no>
> Tested-by: Susant Sahani <susant@redhat.com>
> ---
>  net/ipv4/ipip.c       | 1 +
>  net/ipv6/ip6_tunnel.c | 1 +
>  net/ipv6/sit.c        | 1 +
>  3 files changed, 3 insertions(+)

But tunnel modules are autoloaded now.
If I create a tunnel with ip tunnel based on the existing MODULE_ALIAS_NETDEV().

Re: [PATCH] net: tunnels - enable module autoloading

[Tom Gundersen]

On Thu, May 15, 2014 at 11:32 PM, Stephen Hemminger
<stephen@networkplumber.org> wrote:
> On Tue, 13 May 2014 10:48:28 +0200
> Tom Gundersen <teg@jklm.no> wrote:
>
>> Enable the module alias hookup to allow tunnel modules to be autoloaded on demand.
>>
>> This is in line with how most other netdev kinds work, and will allow userspace
>> to create tunnels without having CAP_SYS_MODULE.
>>
>> Signed-off-by: Tom Gundersen <teg@jklm.no>
>> Tested-by: Susant Sahani <susant@redhat.com>
>> ---
>>  net/ipv4/ipip.c       | 1 +
>>  net/ipv6/ip6_tunnel.c | 1 +
>>  net/ipv6/sit.c        | 1 +
>>  3 files changed, 3 insertions(+)
>
> But tunnel modules are autoloaded now.
> If I create a tunnel with ip tunnel based on the existing MODULE_ALIAS_NETDEV().

Hm, please correct me if I'm wrong, but this only works if you create
a tunnel with one of the hardcoded tunnel names, right? And also, if I
read the code correctly, it only works if you use the ioctl interface
and not the rtnl interface?

What we'd like to do is to use the rtnl interface to create tunnels
with arbitrary names, is there a way this can already be done that I
have missed?

Cheers,

Tom