[PATCH] tipc: fix build issue when building without IPv6

[PATCH] tipc: fix build issue when building without IPv6

[Marcelo Ricardo Leitner]

We can't directly call ipv6_sock_mc_join() but should use the stub
instead and protect it around IS_ENABLED.

Fixes: d0f91938bede ("tipc: add ip/udp media type")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 net/tipc/udp_media.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 04836dd70c2bb79906307ec40e0cbd7b2589978e..e64634062aff3633bd91064567fe7a914bd6df32 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -44,6 +44,7 @@
 #include <net/sock.h>
 #include <net/ip.h>
 #include <net/udp_tunnel.h>
+#include <net/addrconf.h>
 #include <linux/tipc_netlink.h>
 #include "core.h"
 #include "bearer.h"
@@ -247,10 +248,13 @@ static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
 		mreqn.imr_multiaddr = remote->ipv4;
 		mreqn.imr_ifindex = ub->ifindex;
 		err = ip_mc_join_group(sk, &mreqn);
+#if IS_ENABLED(CONFIG_IPV6)
 	} else {
 		if (!ipv6_addr_is_multicast(&remote->ipv6))
 			return 0;
-		err = ipv6_sock_mc_join(sk, ub->ifindex, &remote->ipv6);
+		err = ipv6_stub->ipv6_sock_mc_join(sk, ub->ifindex,
+						   &remote->ipv6);
+#endif
 	}
 	return err;
 }
@@ -387,6 +391,11 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 	tuncfg.encap_destroy = NULL;
 	setup_udp_tunnel_sock(net, ub->ubsock, &tuncfg);
 
+	/* At this point, IPv6 module should have been loaded in
+	 * udp_sock_create/sock_create_kern().
+	 */
+	BUG_ON(!ipv6_stub);
+
 	if (enable_mcast(ub, remote))
 		goto err;
 	return 0;
-- 
2.1.0

Re: [PATCH] tipc: fix build issue when building without IPv6

[David Miller]

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: Thu, 19 Mar 2015 12:13:43 -0300

> @@ -387,6 +391,11 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
>  	tuncfg.encap_destroy = NULL;
>  	setup_udp_tunnel_sock(net, ub->ubsock, &tuncfg);
>  
> +	/* At this point, IPv6 module should have been loaded in
> +	 * udp_sock_create/sock_create_kern().
> +	 */
> +	BUG_ON(!ipv6_stub);
> +

If IPV6=n this will be NULL no matter what.

And if the module load gets an error, this will be NULL as well.

Re: [PATCH] tipc: fix build issue when building without IPv6

[Marcelo Ricardo Leitner]

On 19-03-2015 16:04, David Miller wrote:
> From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> Date: Thu, 19 Mar 2015 12:13:43 -0300
>
>> @@ -387,6 +391,11 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
>>   	tuncfg.encap_destroy = NULL;
>>   	setup_udp_tunnel_sock(net, ub->ubsock, &tuncfg);
>>
>> +	/* At this point, IPv6 module should have been loaded in
>> +	 * udp_sock_create/sock_create_kern().
>> +	 */
>> +	BUG_ON(!ipv6_stub);
>> +
>
> If IPV6=n this will be NULL no matter what.
>
> And if the module load gets an error, this will be NULL as well.
>

Oh indeed, and it (whatever check) should have been placed in a 
ipv6-only path, like vxlan used to do.

Will fix, thanks.

   Marcelo

[PATCH v2] tipc: fix build issue when building without IPv6

[Marcelo Ricardo Leitner]

We can't directly call ipv6_sock_mc_join() but should use the stub
instead and protect it around IS_ENABLED.

Fixes: d0f91938bede ("tipc: add ip/udp media type")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---

Notes:
    The BUG_ON I had placed is completelly unnecessary:
    - with IPV6=n, the code it was trying to protect won't exist
    - if the module load fails, the socket creation a bit above
      enable_mcast() call will return an error and it will bail out
      before reaching that code.
    And thus, just removed in this v2.

 net/tipc/udp_media.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 04836dd70c2bb79906307ec40e0cbd7b2589978e..ac89101e5d1b62165cbdb070d9f4bebe287fc583 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -44,6 +44,7 @@
 #include <net/sock.h>
 #include <net/ip.h>
 #include <net/udp_tunnel.h>
+#include <net/addrconf.h>
 #include <linux/tipc_netlink.h>
 #include "core.h"
 #include "bearer.h"
@@ -247,10 +248,13 @@ static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
 		mreqn.imr_multiaddr = remote->ipv4;
 		mreqn.imr_ifindex = ub->ifindex;
 		err = ip_mc_join_group(sk, &mreqn);
+#if IS_ENABLED(CONFIG_IPV6)
 	} else {
 		if (!ipv6_addr_is_multicast(&remote->ipv6))
 			return 0;
-		err = ipv6_sock_mc_join(sk, ub->ifindex, &remote->ipv6);
+		err = ipv6_stub->ipv6_sock_mc_join(sk, ub->ifindex,
+						   &remote->ipv6);
+#endif
 	}
 	return err;
 }
-- 
2.1.0

Re: [PATCH v2] tipc: fix build issue when building without IPv6

[David Miller]

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: Thu, 19 Mar 2015 16:47:58 -0300

> We can't directly call ipv6_sock_mc_join() but should use the stub
> instead and protect it around IS_ENABLED.
> 
> Fixes: d0f91938bede ("tipc: add ip/udp media type")
> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

This works better, applied, thanks.

Re: [PATCH v2] tipc: fix build issue when building without IPv6

[Ying Xue]

On 03/20/2015 04:06 AM, David Miller wrote:
> From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> Date: Thu, 19 Mar 2015 16:47:58 -0300
> 
>> We can't directly call ipv6_sock_mc_join() but should use the stub
>> instead and protect it around IS_ENABLED.
>>
>> Fixes: d0f91938bede ("tipc: add ip/udp media type")
>> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> 

Sorry, this patch doesn't work at all especially when IPV6=m and TIPC=y. For
example, when we use the combination of the kernel config options, error appears
like:

net/built-in.o: In function `tipc_udp_send_msg':
/home/ying/work/tipc/tipc2.0/net-next-2.6-debug/net/tipc/udp_media.c:196:
undefined reference to `ip6_dst_lookup'
make: *** [vmlinux] Error 1

Instead, I ever tried to fix the issue several days ago. Please refer to the thread:

https://patchwork.ozlabs.org/patch/448836/

According to the suggestion David gave lastly, we should separate the UDP media
as an independent module, make TIPC_MEDIA_UDP depend on (IPV6 || IPV6=n), and
mark TIPC_MEDIA_UDP tristate. Now I am busy doing this following the proposal.

Regards,
Ying

> This works better, applied, thanks.
> --
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> 
> 

Re: [PATCH v2] tipc: fix build issue when building without IPv6

[Marcelo]

On Fri, 20 Mar 2015 10:09:26 +0800, Ying Xue <ying.xue@windriver.com>
wrote:
> On 03/20/2015 04:06 AM, David Miller wrote:
>> From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
>> Date: Thu, 19 Mar 2015 16:47:58 -0300
>> 
>>> We can't directly call ipv6_sock_mc_join() but should use the stub
>>> instead and protect it around IS_ENABLED.
>>>
>>> Fixes: d0f91938bede ("tipc: add ip/udp media type")
>>> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
>> 
> 
> Sorry, this patch doesn't work at all especially when IPV6=m and TIPC=y.
> For
> example, when we use the combination of the kernel config options, error
> appears
> like:
> 
> net/built-in.o: In function `tipc_udp_send_msg':
>
/home/ying/work/tipc/tipc2.0/net-next-2.6-debug/net/tipc/udp_media.c:196:
> undefined reference to `ip6_dst_lookup'
> make: *** [vmlinux] Error 1
> 
> Instead, I ever tried to fix the issue several days ago. Please refer to
> the thread:
> 
> https://patchwork.ozlabs.org/patch/448836/
> 
> According to the suggestion David gave lastly, we should separate the
UDP
> media
> as an independent module, make TIPC_MEDIA_UDP depend on (IPV6 ||
IPV6=n),
> and
> mark TIPC_MEDIA_UDP tristate. Now I am busy doing this following the
> proposal.

I missed your work on the issue, Ying, sorry, otherwise I would have
replied
to that thread instead of posting the patch.

I think David and Willem suggestion were more about the dependencies
than fixing the build issue itself. I mean, if some part of TIPC really
needs IPv6 in order to work or something like that.

So if all we want to do if fix the build issue, I have another suggestion.
When we have IPV6=m and TIPC=y, just have to use the stub too.

(cut & pasted)
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -193,7 +193,7 @@ static int tipc_udp_send_msg(struct net *net, struct
sk_buff *skb,
                        .saddr = src->ipv6,
                        .flowi6_proto = IPPROTO_UDP
                };
-               err = ip6_dst_lookup(ub->ubsock->sk, &ndst, &fl6);
+               err = ipv6_stub->ipv6_dst_lookup(ub->ubsock->sk, &ndst,
&fl6);
                if (err)
                        goto tx_error;
                ttl = ip6_dst_hoplimit(ndst);

then it builds fine here. That is, assuming that you can't reach this code
while
ipv6 module is unloaded.. (I didn't check that) what do you think?

Regards,
Marcelo

Re: [PATCH v2] tipc: fix build issue when building without IPv6

[Ying Xue]

On 03/20/2015 08:35 PM, Marcelo wrote:
> I think David and Willem suggestion were more about the dependencies
> than fixing the build issue itself. I mean, if some part of TIPC really
> needs IPv6 in order to work or something like that.
> 
> So if all we want to do if fix the build issue, I have another suggestion.
> When we have IPV6=m and TIPC=y, just have to use the stub too.
> 
> (cut & pasted)
> --- a/net/tipc/udp_media.c
> +++ b/net/tipc/udp_media.c
> @@ -193,7 +193,7 @@ static int tipc_udp_send_msg(struct net *net, struct
> sk_buff *skb,
>                         .saddr = src->ipv6,
>                         .flowi6_proto = IPPROTO_UDP
>                 };
> -               err = ip6_dst_lookup(ub->ubsock->sk, &ndst, &fl6);
> +               err = ipv6_stub->ipv6_dst_lookup(ub->ubsock->sk, &ndst,
> &fl6);
>                 if (err)
>                         goto tx_error;
>                 ttl = ip6_dst_hoplimit(ndst);
> 
> then it builds fine here. That is, assuming that you can't reach this code
> while
> ipv6 module is unloaded.. (I didn't check that) what do you think?

It seems that your above change is useless to kill the error. For instance, when
I apply it into my project, below build error appears:

net/tipc/udp_media.c: In function ‘tipc_udp_send_msg’:
net/tipc/udp_media.c:196:18: error: ‘const struct ipv6_stub’ has no member named
‘ip6_dst_lookup’
make[2]: *** [net/tipc/udp_media.o] Error 1
make[1]: *** [net/tipc] Error 2
make: *** [net] Error 2

In my opinion, we have to follow David's suggestion dividing the udp_media.c as
an separate module.

Regards,
Ying

Re: [PATCH v2] tipc: fix build issue when building without IPv6

[Marcelo Ricardo Leitner]

On 23-03-2015 00:00, Ying Xue wrote:
> On 03/20/2015 08:35 PM, Marcelo wrote:
>> I think David and Willem suggestion were more about the dependencies
>> than fixing the build issue itself. I mean, if some part of TIPC really
>> needs IPv6 in order to work or something like that.
>>
>> So if all we want to do if fix the build issue, I have another suggestion.
>> When we have IPV6=m and TIPC=y, just have to use the stub too.
>>
>> (cut & pasted)
>> --- a/net/tipc/udp_media.c
>> +++ b/net/tipc/udp_media.c
>> @@ -193,7 +193,7 @@ static int tipc_udp_send_msg(struct net *net, struct
>> sk_buff *skb,
>>                          .saddr = src->ipv6,
>>                          .flowi6_proto = IPPROTO_UDP
>>                  };
>> -               err = ip6_dst_lookup(ub->ubsock->sk, &ndst, &fl6);
>> +               err = ipv6_stub->ipv6_dst_lookup(ub->ubsock->sk, &ndst,
>> &fl6);
>>                  if (err)
>>                          goto tx_error;
>>                  ttl = ip6_dst_hoplimit(ndst);
>>
>> then it builds fine here. That is, assuming that you can't reach this code
>> while
>> ipv6 module is unloaded.. (I didn't check that) what do you think?
>
> It seems that your above change is useless to kill the error. For instance, when
> I apply it into my project, below build error appears:
>
> net/tipc/udp_media.c: In function ‘tipc_udp_send_msg’:
> net/tipc/udp_media.c:196:18: error: ‘const struct ipv6_stub’ has no member named
> ‘ip6_dst_lookup’
> make[2]: *** [net/tipc/udp_media.o] Error 1
> make[1]: *** [net/tipc] Error 2
> make: *** [net] Error 2
>
> In my opinion, we have to follow David's suggestion dividing the udp_media.c as
> an separate module.

If you had checked which members ipv6_stub has, you would have noticed 
the member name has an extra 'v' than the actual function name.
ip6_ -> ipv6_

How it goes then?

Regards,
Marcelo