[PATCH net-next] net: filter: move load_pointer() into filter.h

[PATCH net-next] net: filter: move load_pointer() into filter.h

[Zi Shen Lim]

load_pointer() is already a static inline function.
Let's move it into filter.h so BPF JIT implementations can reuse this
function.

Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
---
This patch is based on discussion with Alexei in the context of
reusing load_pointer for upcoming arm64 BPF JIT compiler. [1]

Compile tested on x86_64 and arm64.

[1] https://lkml.org/lkml/2014/7/3/14

 include/linux/filter.h | 13 +++++++++++++
 net/core/filter.c      |  9 ---------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/include/linux/filter.h b/include/linux/filter.h
index a7e3c48..2288e31 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -6,6 +6,7 @@
 
 #include <linux/atomic.h>
 #include <linux/compat.h>
+#include <linux/skbuff.h>
 #include <linux/workqueue.h>
 #include <uapi/linux/filter.h>
 
@@ -406,6 +407,18 @@ static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 	}
 }
 
+void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
+					   int k, unsigned int size);
+
+static inline void *load_pointer(const struct sk_buff *skb, int k,
+				 unsigned int size, void *buffer)
+{
+	if (k >= 0)
+		return skb_header_pointer(skb, k, size, buffer);
+
+	return bpf_internal_load_pointer_neg_helper(skb, k, size);
+}
+
 #ifdef CONFIG_BPF_JIT
 #include <stdarg.h>
 #include <linux/linkage.h>
diff --git a/net/core/filter.c b/net/core/filter.c
index 1dbf646..1c726ea 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -84,15 +84,6 @@ void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, uns
 	return NULL;
 }
 
-static inline void *load_pointer(const struct sk_buff *skb, int k,
-				 unsigned int size, void *buffer)
-{
-	if (k >= 0)
-		return skb_header_pointer(skb, k, size, buffer);
-
-	return bpf_internal_load_pointer_neg_helper(skb, k, size);
-}
-
 /**
  *	sk_filter - run a packet through a socket filter
  *	@sk: sock associated with &sk_buff
-- 
1.9.1

Re: [PATCH net-next] net: filter: move load_pointer() into filter.h

[Daniel Borkmann]

Hi Zi,

On 07/03/2014 09:52 AM, Zi Shen Lim wrote:
> load_pointer() is already a static inline function.
> Let's move it into filter.h so BPF JIT implementations can reuse this
> function.
>
> Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
> ---
> This patch is based on discussion with Alexei in the context of
> reusing load_pointer for upcoming arm64 BPF JIT compiler. [1]
>
> Compile tested on x86_64 and arm64.
>
> [1] https://lkml.org/lkml/2014/7/3/14
>
>   include/linux/filter.h | 13 +++++++++++++
>   net/core/filter.c      |  9 ---------
>   2 files changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index a7e3c48..2288e31 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -6,6 +6,7 @@
>
>   #include <linux/atomic.h>
>   #include <linux/compat.h>
> +#include <linux/skbuff.h>
>   #include <linux/workqueue.h>
>   #include <uapi/linux/filter.h>
>
> @@ -406,6 +407,18 @@ static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
>   	}
>   }
>
> +void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
> +					   int k, unsigned int size);
> +
> +static inline void *load_pointer(const struct sk_buff *skb, int k,
> +				 unsigned int size, void *buffer)
> +{

Fine by me, but since you're exporting this into a header,
please give this a more specific name, such as bpf_load_pointer(),
for example.

Thanks,

Daniel

Re: [PATCH net-next] net: filter: move load_pointer() into filter.h

[Z Lim]

On Thu, Jul 3, 2014 at 1:10 AM, Daniel Borkmann <dborkman@redhat.com> wrote:
> Hi Zi,
>
>
> On 07/03/2014 09:52 AM, Zi Shen Lim wrote:
>>
>> load_pointer() is already a static inline function.
>> Let's move it into filter.h so BPF JIT implementations can reuse this
>> function.
>>
>> Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
>> ---
>> This patch is based on discussion with Alexei in the context of
>> reusing load_pointer for upcoming arm64 BPF JIT compiler. [1]
>>
>> Compile tested on x86_64 and arm64.
>>
>> [1] https://lkml.org/lkml/2014/7/3/14
>>
>>   include/linux/filter.h | 13 +++++++++++++
>>   net/core/filter.c      |  9 ---------
>>   2 files changed, 13 insertions(+), 9 deletions(-)
>>
>> diff --git a/include/linux/filter.h b/include/linux/filter.h
>> index a7e3c48..2288e31 100644
>> --- a/include/linux/filter.h
>> +++ b/include/linux/filter.h
>> @@ -6,6 +6,7 @@
>>
>>   #include <linux/atomic.h>
>>   #include <linux/compat.h>
>> +#include <linux/skbuff.h>
>>   #include <linux/workqueue.h>
>>   #include <uapi/linux/filter.h>
>>
>> @@ -406,6 +407,18 @@ static inline u16 bpf_anc_helper(const struct
>> sock_filter *ftest)
>>         }
>>   }
>>
>> +void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
>> +                                          int k, unsigned int size);
>> +
>> +static inline void *load_pointer(const struct sk_buff *skb, int k,
>> +                                unsigned int size, void *buffer)
>> +{
>
>
> Fine by me, but since you're exporting this into a header,
> please give this a more specific name, such as bpf_load_pointer(),
> for example.

Daniel, thanks for the suggestion. I'll send out v2 shortly.

>
> Thanks,
>
> Daniel