RE: selftests: net: l2tp.sh regression starting with 6.1-rc1

[Drewek, Wojciech]

> -----Original Message-----
> From: Andrea Righi <andrea.righi@xxxxxxxxxxxxx>
> Sent: czwartek, 30 marca 2023 08:45
> To: Guillaume Nault <gnault@xxxxxxxxxx>
> Cc: Drewek, Wojciech <wojciech.drewek@xxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric Dumazet
> <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>; Shuah Khan <shuah@xxxxxxxxxx>;
> netdev@xxxxxxxxxxxxxxx; linux-kselftest@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: selftests: net: l2tp.sh regression starting with 6.1-rc1
> 
> On Wed, Mar 29, 2023 at 06:52:20PM +0200, Guillaume Nault wrote:
> > On Wed, Mar 29, 2023 at 03:39:13PM +0000, Drewek, Wojciech wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > -MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
> > > > -MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
> > > > +MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, 115 /* IPPROTO_L2TP */);
> > > > +MODULE_ALIAS_NET_PF_PROTO(PF_INET6, 115 /* IPPROTO_L2TP */);
> > >
> > > Btw, am I blind or the alias with type was wrong the whole time?
> > > pf goes first, then proto and type at the end according to the definition of MODULE_ALIAS_NET_PF_PROTO_TYPE
> > > and here type (2) is 2nd and proto (115) is 3rd
> >
> > You're not blind :). The MODULE_ALIAS_NET_PF_PROTO_TYPE(...) is indeed
> > wrong. Auto-loading the l2tp_ip and l2tp_ip6 modules only worked
> > because of the extra MODULE_ALIAS_NET_PF_PROTO() declaration (as
> > inet_create() and inet6_create() fallback to "net-pf-%d-proto-%d" if
> > "net-pf-%d-proto-%d-type-%d" fails).
> 
> At this point I think using 115 directly is probably the best solution,
> that is also what we do already with SOCK_DGRAM, but I would just update
> the comment up above, instead of adding the inline comments.

Agree,

I verified the fix on my machine, 
Do you want me to send the patch or you'll just send below one?

> 
> Something like this maybe:
> 
> ---
> 
> From: Andrea Righi <andrea.righi@xxxxxxxxxxxxx>
> Subject: [PATCH] l2tp: generate correct module alias strings
> 
> Commit 65b32f801bfb ("uapi: move IPPROTO_L2TP to in.h") moved the
> definition of IPPROTO_L2TP from a define to an enum, but since
> __stringify doesn't work properly with enums, we ended up breaking the
> modalias strings for the l2tp modules:
> 
>  $ modinfo l2tp_ip l2tp_ip6 | grep alias
>  alias:          net-pf-2-proto-IPPROTO_L2TP
>  alias:          net-pf-2-proto-2-type-IPPROTO_L2TP
>  alias:          net-pf-10-proto-IPPROTO_L2TP
>  alias:          net-pf-10-proto-2-type-IPPROTO_L2TP
> 
> Use the resolved number directly in MODULE_ALIAS_*() macros (as we
> already do with SOCK_DGRAM) to fix the alias strings:
> 
> $ modinfo l2tp_ip l2tp_ip6 | grep alias
> alias:          net-pf-2-proto-115
> alias:          net-pf-2-proto-115-type-2
> alias:          net-pf-10-proto-115
> alias:          net-pf-10-proto-115-type-2
> 
> Moreover, fix the ordering of the parameters passed to
> MODULE_ALIAS_NET_PF_PROTO_TYPE() by switching proto and type.
> 
> Fixes: 65b32f801bfb ("uapi: move IPPROTO_L2TP to in.h")
> Signed-off-by: Guillaume Nault <gnault@xxxxxxxxxx>
> Signed-off-by: Andrea Righi <andrea.righi@xxxxxxxxxxxxx>
> ---
>  net/l2tp/l2tp_ip.c  | 8 ++++----
>  net/l2tp/l2tp_ip6.c | 8 ++++----
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
> index 4db5a554bdbd..41a74fc84ca1 100644
> --- a/net/l2tp/l2tp_ip.c
> +++ b/net/l2tp/l2tp_ip.c
> @@ -677,8 +677,8 @@ MODULE_AUTHOR("James Chapman <jchapman@xxxxxxxxxxx>");
>  MODULE_DESCRIPTION("L2TP over IP");
>  MODULE_VERSION("1.0");
> 
> -/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
> - * enums
> +/* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol,
> + * because __stringify doesn't like enums
>   */
> -MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
> -MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);
> +MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 115, 2);
> +MODULE_ALIAS_NET_PF_PROTO(PF_INET, 115);
> diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
> index 2478aa60145f..5137ea1861ce 100644
> --- a/net/l2tp/l2tp_ip6.c
> +++ b/net/l2tp/l2tp_ip6.c
> @@ -806,8 +806,8 @@ MODULE_AUTHOR("Chris Elston <celston@xxxxxxxxxxx>");
>  MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
>  MODULE_VERSION("1.0");
> 
> -/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
> - * enums
> +/* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol,
> + * because __stringify doesn't like enums
>   */
> -MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
> -MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
> +MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 115, 2);
> +MODULE_ALIAS_NET_PF_PROTO(PF_INET6, 115);
> --
> 2.39.2