[PATCH] samples/bpf: Fix tc and ip path in xdp2skb_meta.sh

[PATCH] samples/bpf: Fix tc and ip path in xdp2skb_meta.sh

[Taeung Song]

The below path error can occur:

  # ./xdp2skb_meta.sh --dev eth0 --list
  ./xdp2skb_meta.sh: line 61: /usr/sbin/tc: No such file or directory

  # which tc
  /sbin/tc

So use 'which' command instead of absolute path of tc and ip

Fixes: 36e04a2d78d9 ("samples/bpf: xdp2skb_meta shows transferring info from XDP to SKB")
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
---
 samples/bpf/xdp2skb_meta.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/samples/bpf/xdp2skb_meta.sh b/samples/bpf/xdp2skb_meta.sh
index b9c9549c4c27..67cf7b5f336d 100755
--- a/samples/bpf/xdp2skb_meta.sh
+++ b/samples/bpf/xdp2skb_meta.sh
@@ -16,8 +16,8 @@
 BPF_FILE=xdp2skb_meta_kern.o
 DIR=$(dirname $0)
 
-export TC=/usr/sbin/tc
-export IP=/usr/sbin/ip
+export TC=`which tc`
+export IP=`which ip`
 
 function usage() {
     echo ""
-- 
2.17.1

Re: [PATCH] samples/bpf: Fix tc and ip path in xdp2skb_meta.sh

[Jesper Dangaard Brouer]

On Tue, 10 Jul 2018 00:04:18 +0900
Taeung Song <treeze.taeung@gmail.com> wrote:

> The below path error can occur:
> 
>   # ./xdp2skb_meta.sh --dev eth0 --list
>   ./xdp2skb_meta.sh: line 61: /usr/sbin/tc: No such file or directory
> 
>   # which tc
>   /sbin/tc
> 
> So use 'which' command instead of absolute path of tc and ip
> 
> Fixes: 36e04a2d78d9 ("samples/bpf: xdp2skb_meta shows transferring info from XDP to SKB")
> Cc: Jesper Dangaard Brouer <brouer@redhat.com>
> Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
> ---
>  samples/bpf/xdp2skb_meta.sh | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/samples/bpf/xdp2skb_meta.sh b/samples/bpf/xdp2skb_meta.sh
> index b9c9549c4c27..67cf7b5f336d 100755
> --- a/samples/bpf/xdp2skb_meta.sh
> +++ b/samples/bpf/xdp2skb_meta.sh
> @@ -16,8 +16,8 @@
>  BPF_FILE=xdp2skb_meta_kern.o
>  DIR=$(dirname $0)
>  
> -export TC=/usr/sbin/tc
> -export IP=/usr/sbin/ip
> +export TC=`which tc`
> +export IP=`which ip`

This is not a good solution, as 'which' can return something else.
E.g. on my system I've aliased 'tc' to 'sudo tc', and `which tc` returns:

$ which tc
alias tc='sudo tc'
	/usr/bin/sudo

The easiest solution is to simply do:

 export TC=tc
 export IP=ip

The more fancy solution is to allow callers to redefine $IP and $TC:

[ -z "$TC" ] && TC=tc
[ -z "$IP" ] && IP=ip

And then you should also fix the use of 'basename', see below patch...
-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

diff --git a/samples/bpf/xdp2skb_meta.sh b/samples/bpf/xdp2skb_meta.sh
index b9c9549c4c27..4bde9d066c46 100755
--- a/samples/bpf/xdp2skb_meta.sh
+++ b/samples/bpf/xdp2skb_meta.sh
@@ -16,8 +16,8 @@
 BPF_FILE=xdp2skb_meta_kern.o
 DIR=$(dirname $0)
 
-export TC=/usr/sbin/tc
-export IP=/usr/sbin/ip
+[ -z "$TC" ] && TC=tc
+[ -z "$IP" ] && IP=ip
 
 function usage() {
     echo ""
@@ -53,7 +53,7 @@ function _call_cmd() {
     local allow_fail="$2"
     shift 2
     if [[ -n "$VERBOSE" ]]; then
-	echo "$(basename $cmd) $@"
+	echo "$cmd $@"
     fi
     if [[ -n "$DRYRUN" ]]; then
 	return

Re: [PATCH] samples/bpf: Fix tc and ip path in xdp2skb_meta.sh

[Taeung Song]

Hi Jesper Dangaard Brouer,

On 07/10/2018 12:40 AM, Jesper Dangaard Brouer wrote:
> On Tue, 10 Jul 2018 00:04:18 +0900
> Taeung Song <treeze.taeung@gmail.com> wrote:
> 
>> The below path error can occur:
>>
>>    # ./xdp2skb_meta.sh --dev eth0 --list
>>    ./xdp2skb_meta.sh: line 61: /usr/sbin/tc: No such file or directory
>>
>>    # which tc
>>    /sbin/tc
>>
>> So use 'which' command instead of absolute path of tc and ip
>>
>> Fixes: 36e04a2d78d9 ("samples/bpf: xdp2skb_meta shows transferring info from XDP to SKB")
>> Cc: Jesper Dangaard Brouer <brouer@redhat.com>
>> Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
>> ---
>>   samples/bpf/xdp2skb_meta.sh | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/samples/bpf/xdp2skb_meta.sh b/samples/bpf/xdp2skb_meta.sh
>> index b9c9549c4c27..67cf7b5f336d 100755
>> --- a/samples/bpf/xdp2skb_meta.sh
>> +++ b/samples/bpf/xdp2skb_meta.sh
>> @@ -16,8 +16,8 @@
>>   BPF_FILE=xdp2skb_meta_kern.o
>>   DIR=$(dirname $0)
>>   
>> -export TC=/usr/sbin/tc
>> -export IP=/usr/sbin/ip
>> +export TC=`which tc`
>> +export IP=`which ip`
> 
> This is not a good solution, as 'which' can return something else.
> E.g. on my system I've aliased 'tc' to 'sudo tc', and `which tc` returns:
> 
> $ which tc
> alias tc='sudo tc'
> 	/usr/bin/sudo
> 
> The easiest solution is to simply do:
> 
>   export TC=tc
>   export IP=ip
> 
> The more fancy solution is to allow callers to redefine $IP and $TC:
> 
> [ -z "$TC" ] && TC=tc
> [ -z "$IP" ] && IP=ip
> 

Yep, you are right, I'll change it.

> And then you should also fix the use of 'basename', see below patch...
> 

I thought it'd be fine to leave 'basename' as it is,
because if callers redefine TC=/home/taeung/tc and give
the options --verbose or --dry-run, 'basename' can more tidily show outputs.

But it seems to be trivial, I'll resend this patch as v2 based on your 
comment !

Thanks,
Taeung

Re: [PATCH] samples/bpf: Fix tc and ip path in xdp2skb_meta.sh

[Jesper Dangaard Brouer]

On Tue, 10 Jul 2018 02:44:06 +0900
Taeung Song <treeze.taeung@gmail.com> wrote:

> Hi Jesper Dangaard Brouer,
> 
> On 07/10/2018 12:40 AM, Jesper Dangaard Brouer wrote:
> > On Tue, 10 Jul 2018 00:04:18 +0900
> > Taeung Song <treeze.taeung@gmail.com> wrote:
> >   
> >> The below path error can occur:
> >>
> >>    # ./xdp2skb_meta.sh --dev eth0 --list
> >>    ./xdp2skb_meta.sh: line 61: /usr/sbin/tc: No such file or directory
> >>
> >>    # which tc
> >>    /sbin/tc
> >>
> >> So use 'which' command instead of absolute path of tc and ip
> >>
> >> Fixes: 36e04a2d78d9 ("samples/bpf: xdp2skb_meta shows transferring info from XDP to SKB")
> >> Cc: Jesper Dangaard Brouer <brouer@redhat.com>
> >> Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
> >> ---
> >>   samples/bpf/xdp2skb_meta.sh | 4 ++--
> >>   1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/samples/bpf/xdp2skb_meta.sh b/samples/bpf/xdp2skb_meta.sh
> >> index b9c9549c4c27..67cf7b5f336d 100755
> >> --- a/samples/bpf/xdp2skb_meta.sh
> >> +++ b/samples/bpf/xdp2skb_meta.sh
> >> @@ -16,8 +16,8 @@
> >>   BPF_FILE=xdp2skb_meta_kern.o
> >>   DIR=$(dirname $0)
> >>   
> >> -export TC=/usr/sbin/tc
> >> -export IP=/usr/sbin/ip
> >> +export TC=`which tc`
> >> +export IP=`which ip`  
> > 
> > This is not a good solution, as 'which' can return something else.
> > E.g. on my system I've aliased 'tc' to 'sudo tc', and `which tc` returns:
> > 
> > $ which tc
> > alias tc='sudo tc'
> > 	/usr/bin/sudo
> > 
> > The easiest solution is to simply do:
> > 
> >   export TC=tc
> >   export IP=ip
> > 
> > The more fancy solution is to allow callers to redefine $IP and $TC:
> > 
> > [ -z "$TC" ] && TC=tc
> > [ -z "$IP" ] && IP=ip
> >   
> 
> Yep, you are right, I'll change it.
> 
> > And then you should also fix the use of 'basename', see below patch...
> >   
> 
> I thought it'd be fine to leave 'basename' as it is,
> because if callers redefine TC=/home/taeung/tc and give
> the options --verbose or --dry-run, 'basename' can more tidily show outputs.

The 'basename' does not work correctly if e.g. TC='sudo tc'.

Below output is with 'basename' removed, else it would say "sudo qdisc del ..."

TC='sudo tc' IP='sudo ip' ./xdp2skb_meta.sh -v --dev mlx5p1 --dry-run
# Device set to: DEV=mlx5p1
# Dry-run mode: enable VERBOSE and don't call TC+IP
sudo tc qdisc del dev mlx5p1 clsact
sudo tc qdisc add dev mlx5p1 clsact
sudo tc filter add dev mlx5p1 ingress prio 1 handle 1 bpf da obj ./xdp2skb_meta_kern.o sec tc_mark
# Flush XDP on device: mlx5p1
sudo ip link set dev mlx5p1 xdp off
sudo ip link set dev mlx5p1 xdp obj ./xdp2skb_meta_kern.o sec xdp_mark


> But it seems to be trivial, I'll resend this patch as v2 based on your 
> comment !

Thx, already ACKed it :-)

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

Re: [PATCH] samples/bpf: Fix tc and ip path in xdp2skb_meta.sh

[Taeung Song]

On 07/10/2018 04:20 AM, Jesper Dangaard Brouer wrote:
> On Tue, 10 Jul 2018 02:44:06 +0900
> Taeung Song <treeze.taeung@gmail.com> wrote:
> 
>> Hi Jesper Dangaard Brouer,
>>
>> On 07/10/2018 12:40 AM, Jesper Dangaard Brouer wrote:
>>> On Tue, 10 Jul 2018 00:04:18 +0900
>>> Taeung Song <treeze.taeung@gmail.com> wrote:
>>>    
>>>> The below path error can occur:
>>>>
>>>>     # ./xdp2skb_meta.sh --dev eth0 --list
>>>>     ./xdp2skb_meta.sh: line 61: /usr/sbin/tc: No such file or directory
>>>>
>>>>     # which tc
>>>>     /sbin/tc
>>>>
>>>> So use 'which' command instead of absolute path of tc and ip
>>>>
>>>> Fixes: 36e04a2d78d9 ("samples/bpf: xdp2skb_meta shows transferring info from XDP to SKB")
>>>> Cc: Jesper Dangaard Brouer <brouer@redhat.com>
>>>> Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
>>>> ---
>>>>    samples/bpf/xdp2skb_meta.sh | 4 ++--
>>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/samples/bpf/xdp2skb_meta.sh b/samples/bpf/xdp2skb_meta.sh
>>>> index b9c9549c4c27..67cf7b5f336d 100755
>>>> --- a/samples/bpf/xdp2skb_meta.sh
>>>> +++ b/samples/bpf/xdp2skb_meta.sh
>>>> @@ -16,8 +16,8 @@
>>>>    BPF_FILE=xdp2skb_meta_kern.o
>>>>    DIR=$(dirname $0)
>>>>    
>>>> -export TC=/usr/sbin/tc
>>>> -export IP=/usr/sbin/ip
>>>> +export TC=`which tc`
>>>> +export IP=`which ip`
>>>
>>> This is not a good solution, as 'which' can return something else.
>>> E.g. on my system I've aliased 'tc' to 'sudo tc', and `which tc` returns:
>>>
>>> $ which tc
>>> alias tc='sudo tc'
>>> 	/usr/bin/sudo
>>>
>>> The easiest solution is to simply do:
>>>
>>>    export TC=tc
>>>    export IP=ip
>>>
>>> The more fancy solution is to allow callers to redefine $IP and $TC:
>>>
>>> [ -z "$TC" ] && TC=tc
>>> [ -z "$IP" ] && IP=ip
>>>    
>>
>> Yep, you are right, I'll change it.
>>
>>> And then you should also fix the use of 'basename', see below patch...
>>>    
>>
>> I thought it'd be fine to leave 'basename' as it is,
>> because if callers redefine TC=/home/taeung/tc and give
>> the options --verbose or --dry-run, 'basename' can more tidily show outputs.
> 
> The 'basename' does not work correctly if e.g. TC='sudo tc'.
> 
> Below output is with 'basename' removed, else it would say "sudo qdisc del ..."
> 
> TC='sudo tc' IP='sudo ip' ./xdp2skb_meta.sh -v --dev mlx5p1 --dry-run
> # Device set to: DEV=mlx5p1
> # Dry-run mode: enable VERBOSE and don't call TC+IP
> sudo tc qdisc del dev mlx5p1 clsact
> sudo tc qdisc add dev mlx5p1 clsact
> sudo tc filter add dev mlx5p1 ingress prio 1 handle 1 bpf da obj ./xdp2skb_meta_kern.o sec tc_mark
> # Flush XDP on device: mlx5p1
> sudo ip link set dev mlx5p1 xdp off
> sudo ip link set dev mlx5p1 xdp obj ./xdp2skb_meta_kern.o sec xdp_mark
> 
> 

Oops, right. I missed the alias case.

>> But it seems to be trivial, I'll resend this patch as v2 based on your
>> comment !
> 
> Thx, already ACKed it :-)
> 

--
Thanks a lot !

Taeung