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List:       openbsd-bugs
Subject:    Re: send without tab! netstat address family and interface, well-known protocols
From:       Jason McIntyre <jmc () kerhand ! co ! uk>
Date:       2020-07-18 21:18:53
Message-ID: 20200718211853.GF4547 () kansas
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On Sat, Jul 18, 2020 at 08:11:15PM +0000, marfabastewart wrote:
> > > >     netstat -p only works for the protocols hard-coded in the protox struct in
> > > >     /usr/src/usr.bin/netstat/main.c
> > > >
> 
> > > >
> > > >     For the protocol problem, I see the call to getprotoent but
> > > >     no call to getprotobyname in the name2protox function in
> > > >     /usr/src/usr.b/in/netstat/main.c
> > > >
> > >
> >
> > so, philip guenther did all the hard work: it seems the text additions
> > were made 21 years ago with ip6 support, but the code was never added.
> > so the current SYNOPSIS was (and still is) correct: -f is not used with
> > -I. the text in -I describing -f was wrong, and i've just removed it.
> >
> > thanks for your mail,
> > jmc
> 
> Hi, thank you very much for your quick reply.
> It also appears that netstat isn't checking /etc/protcols
> when the -p option is called:
> 
> $netstat -an -p rdp
> netstat: rdp: unknown protocol
> 
> although rdp is in /etc/protocols.
> 

well, netstat(1) does not claim to read /etc/protocols, only
that some well known protocols may be listed there:

		 Some protocol names and aliases are listed in the
		 file /etc/protocols.

> In contrast, other protocols in struct protx
> do get a different response:
> 
> $netstat -an -p icmp
> netstat: no protocol handler for protocol icmp
> 
> Although I admit I don't know enough to know
> whether it would make sense to generate statistics
> for icmp.
> 

i'm not sure whether the combination makes sense. looking at SYNOPSIS,
it does suggest it should work. but if you run "-an" without -p it will
show you what protocols are supported for that usage (not icmp).

you want -s for stats:

	$ netstat -s -p icmp

> Of course other protocols like tcp do work without
> problems.
> 

so we could easily add a list of the supported protocol names to -p. i
guess most people will know what makes sense, and if you try "netstat -p
bob" and it errors out, you'll know it isn;t supported. so i'm unsure
whether it's worth adding such a list. personally i think it probably
should...

jmc

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