Re: [net PATCH 1/2] selftests: net: lib: fix broken ping with coreutils ping util

[Christian Marangi <ansuelsmth@gmail.com>]

On Sat, Nov 30, 2024 at 05:48:40PM +0200, Vladimir Oltean wrote:
> On Sat, Nov 30, 2024 at 04:46:14PM +0100, Christian Marangi wrote:
> > On Sat, Nov 30, 2024 at 05:43:07PM +0200, Vladimir Oltean wrote:
> > > On Sat, Nov 30, 2024 at 12:33:09PM +0100, Christian Marangi wrote:
> > > > If the coreutils variant of ping is used instead of the busybox one, the
> > > > ping_do() command is broken. This comes by the fact that for coreutils
> > > > ping, the ping IP needs to be the very last elements.
> > > > 
> > > > To handle this, reorder the ping args and make $dip last element.
> > > > 
> > > > The use of coreutils ping might be useful for case where busybox is not
> > > > compiled with float interval support and ping command doesn't support
> > > > 0.1 interval. (in such case a dedicated ping utility is installed
> > > > instead)
> > > > 
> > > > Cc: stable@vger.kernel.org
> > > > Fixes: 73bae6736b6b ("selftests: forwarding: Add initial testing framework")
> > > > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > > > ---
> > > 
> > > Do you mean the other way around? that the busybox ping is the broken one?
> > > And by coreutils ping, you actually mean iputils ping, right?
> > 
> > Mhh no busybox ping utility is problematic only if FLOAT INTERVAL is not
> > enabled (aka 0.1 interval are not supported)
> > 
> > Yes I'm referring to iputils ping. With that I notice args are wrongly
> > parsed... especially with the -c option.
> 
> But isn't iputils ping what everybody else uses? I'm confused. I have
> this version and the current syntax is not problematic for me.
> 
> $ ping -V
> ping from iputils 20240905
> libcap: yes, IDN: yes, NLS: no, error.h: yes, getrandom(): yes, __fpending(): yes

Mhh the problem seems to be -c 

Let me post some outputs...

root@OpenWrt:~# ping -V
ping from iputils 20240117
libcap: no, IDN: no, NLS: no, error.h: no, getrandom(): yes, __fpending(): yes
root@OpenWrt:~# ping -c 10 192.168.1.1
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.102 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.084 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=0.236 ms
^C
--- 192.168.1.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2080ms
rtt min/avg/max/mdev = 0.084/0.140/0.236/0.067 ms
root@OpenWrt:~# ping 192.168.1.1 -c 10
ping: -c: Name does not resolve

As you can see swapping the ip cause this "Name does not resolve" error.

-- 
	Ansuel