Date: Fri, 30 Dec 1994 13:19:24 -0500 (EST) From: Wankle Rotary Engine <wpaul@skynet.ctr.columbia.edu> To: wollman@halloran-eldar.lcs.mit.edu (Garrett Wollman) Cc: freebsd-hackers@freebsd.org Subject: Re: ifconfig -a Message-ID: <199412301819.NAA00645@skynet.ctr.columbia.edu> In-Reply-To: <9412301553.AA05515@halloran-eldar.lcs.mit.edu> from "Garrett Wollman" at Dec 30, 94 10:53:43 am
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They say this Garrett Wollman person was kidding when he wrote: > > <<On Thu, 29 Dec 1994 19:24:16 -0500 (EST), Wankle Rotary Engine <wpaul@skynet.ctr.columbia.edu> said: > > > of FreeBSD's ifconfig once I get done smacking it around too, since the > > only way I've found to read the hardware address for an interface involves > > kvm_read() and friends (at this very moment I'm furiously cribbing away > > from netstat ;). I already have the -a option working though: > > Do it the same way netstat does; no KVM stuff involved. Er, I don't understand what you're telling me here. Looking at the sources to netstat, the if.c module, which is what is used when you invoke netstat -i, quite clearly calls kvm_read(). (It's wrapped inside a function called kread(), but it's the same thing.) And main.c calles kvm_open() and kvm_nlist(). The kvm_nlist() is used to look up several symbols, including "_ifnet", which is used by if.c to track down the per-interface data. That's how I did it for ifconfig. Are you saying somebody rewrote netstat to not use KVM when I wasn't looking? I only supped my kernel source tree two days ago. I think I'm confused. > > That's right. There's one for each address, INCLUDING THE LINK-LAYER > ADDRESS. So I've discovered. :) > > The ifc_len field should be filled in with the total amount of space > required. I believe that you can do an initial SIOCGIFCONF with > ifc_len set to zero, and then allocate ifc_len space for the buffer > and do it again. Ah... that sounds sensible. Then if no one objects I'll make a new patch that works this way. > > -GAWollman -Bill -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Bill Paul System Manager wpaul@ctr.columbia.edu Center for Telecommunications Research (212) 854-6020 Columbia University, New York City ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The Møøse Illuminati: ignore it and be confused, or join it and be confusing! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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