2021-08-08 12:37:31

by Muhammad Falak R Wani

Subject: [PATCH] samples: bpf: xdp1: remove duplicate code to find protocol

The code to find h_vlan_encapsulated_proto is duplicated.
Remove the extra block.

Signed-off-by: Muhammad Falak R Wani <[email protected]>
---
samples/bpf/xdp1_kern.c | 9 ---------
1 file changed, 9 deletions(-)

diff --git a/samples/bpf/xdp1_kern.c b/samples/bpf/xdp1_kern.c
index 34b64394ed9c..a35e064d7726 100644
--- a/samples/bpf/xdp1_kern.c
+++ b/samples/bpf/xdp1_kern.c
@@ -57,15 +57,6 @@ int xdp_prog1(struct xdp_md *ctx)

h_proto = eth->h_proto;

- if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
- struct vlan_hdr *vhdr;
-
- vhdr = data + nh_off;
- nh_off += sizeof(struct vlan_hdr);
- if (data + nh_off > data_end)
- return rc;
- h_proto = vhdr->h_vlan_encapsulated_proto;
- }
if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
struct vlan_hdr *vhdr;

--
2.17.1

2021-08-08 16:59:22

by Yonghong Song

Subject: Re: [PATCH] samples: bpf: xdp1: remove duplicate code to find protocol

On 8/8/21 5:24 AM, Muhammad Falak R Wani wrote:
> The code to find h_vlan_encapsulated_proto is duplicated.
> Remove the extra block.
>
> Signed-off-by: Muhammad Falak R Wani <[email protected]>
> ---
> samples/bpf/xdp1_kern.c | 9 ---------
> 1 file changed, 9 deletions(-)
>
> diff --git a/samples/bpf/xdp1_kern.c b/samples/bpf/xdp1_kern.c
> index 34b64394ed9c..a35e064d7726 100644
> --- a/samples/bpf/xdp1_kern.c
> +++ b/samples/bpf/xdp1_kern.c
> @@ -57,15 +57,6 @@ int xdp_prog1(struct xdp_md *ctx)
>
> h_proto = eth->h_proto;
>
> - if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
> - struct vlan_hdr *vhdr;
> -
> - vhdr = data + nh_off;
> - nh_off += sizeof(struct vlan_hdr);
> - if (data + nh_off > data_end)
> - return rc;
> - h_proto = vhdr->h_vlan_encapsulated_proto;

No. This is not a duplicate. The h_proto in the above line will be used
in the below "if" condition.

> - }
> if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
> struct vlan_hdr *vhdr;
>
>

2021-08-08 17:54:31

by Muhammad Falak R Wani

Subject: Re: [PATCH] samples: bpf: xdp1: remove duplicate code to find protocol

On Sun, Aug 8, 2021 at 10:23 PM Yonghong Song <[email protected]> wrote:
>
>
>
> On 8/8/21 5:24 AM, Muhammad Falak R Wani wrote:
> > The code to find h_vlan_encapsulated_proto is duplicated.
> > Remove the extra block.
> >
> > Signed-off-by: Muhammad Falak R Wani <[email protected]>
> > ---
> > samples/bpf/xdp1_kern.c | 9 ---------
> > 1 file changed, 9 deletions(-)
> >
> > diff --git a/samples/bpf/xdp1_kern.c b/samples/bpf/xdp1_kern.c
> > index 34b64394ed9c..a35e064d7726 100644
> > --- a/samples/bpf/xdp1_kern.c
> > +++ b/samples/bpf/xdp1_kern.c
> > @@ -57,15 +57,6 @@ int xdp_prog1(struct xdp_md *ctx)
> >
> > h_proto = eth->h_proto;
> >
> > - if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
> > - struct vlan_hdr *vhdr;
> > -
> > - vhdr = data + nh_off;
> > - nh_off += sizeof(struct vlan_hdr);
> > - if (data + nh_off > data_end)
> > - return rc;
> > - h_proto = vhdr->h_vlan_encapsulated_proto;
>
> No. This is not a duplicate. The h_proto in the above line will be used
> in the below "if" condition.
>
> > - }
> > if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
> > struct vlan_hdr *vhdr;
> >
> >
Apologies :(
I now realize, it could be double vlan encapsulated.
Would it make sense to add an explicit comment for newbies like me ?
I can send a patch, if it is okay.

-mfrw

2021-08-09 01:03:54

by Yonghong Song

Subject: Re: [PATCH] samples: bpf: xdp1: remove duplicate code to find protocol

On 8/8/21 10:19 AM, Muhammad Falak Reyaz wrote:
> On Sun, Aug 8, 2021 at 10:23 PM Yonghong Song <[email protected]> wrote:
>>
>>
>>
>> On 8/8/21 5:24 AM, Muhammad Falak R Wani wrote:
>>> The code to find h_vlan_encapsulated_proto is duplicated.
>>> Remove the extra block.
>>>
>>> Signed-off-by: Muhammad Falak R Wani <[email protected]>
>>> ---
>>> samples/bpf/xdp1_kern.c | 9 ---------
>>> 1 file changed, 9 deletions(-)
>>>
>>> diff --git a/samples/bpf/xdp1_kern.c b/samples/bpf/xdp1_kern.c
>>> index 34b64394ed9c..a35e064d7726 100644
>>> --- a/samples/bpf/xdp1_kern.c
>>> +++ b/samples/bpf/xdp1_kern.c
>>> @@ -57,15 +57,6 @@ int xdp_prog1(struct xdp_md *ctx)
>>>
>>> h_proto = eth->h_proto;
>>>
>>> - if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
>>> - struct vlan_hdr *vhdr;
>>> -
>>> - vhdr = data + nh_off;
>>> - nh_off += sizeof(struct vlan_hdr);
>>> - if (data + nh_off > data_end)
>>> - return rc;
>>> - h_proto = vhdr->h_vlan_encapsulated_proto;
>>
>> No. This is not a duplicate. The h_proto in the above line will be used
>> in the below "if" condition.
>>
>>> - }
>>> if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
>>> struct vlan_hdr *vhdr;
>>>
>>>
> Apologies :(
> I now realize, it could be double vlan encapsulated.
> Would it make sense to add an explicit comment for newbies like me ?
> I can send a patch, if it is okay.

This is not the first time people sending a patch trying to remove this
"duplicated" code. I think it is okay to send a patch with comments to
say this is intended to handle nested vlan, so we can save everybody's
time. Thanks.

>
> -mfrw
>