Date: Fri, 29 Aug 2003 19:02:06 +0100 From: Bruce M Simpson <bms@spc.org> To: "Khoa A. To" <takhoa@rice.edu> Cc: FreeBSD_Net <freebsd-net@FreeBSD.ORG> Subject: Re: Reversed MAC lookup inside FreeBSD kernel? Message-ID: <20030829180206.GK1417@spc.org> In-Reply-To: <GAENJNNFCGNNIHDFIDFAMEKLCAAA.takhoa@rice.edu> References: <20030829154401.GA417@newluxor.skynet.org> <GAENJNNFCGNNIHDFIDFAMEKLCAAA.takhoa@rice.edu>
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On Fri, Aug 29, 2003 at 11:17:16AM -0500, Khoa A. To wrote: > I need to get a translation of MAC addresses to IP addresses in the kernel. > I saw some postings about how to translate MAC to IP in the user level, but > they seem to require the host to send a packet to that MAC address and some > other ways that also require the host to actually send some request packets > out. All my MAC-IP addresses are already set statically using "arp -s" in > the ARP table. When I'm in the kernel, how do I get a hold of the ARP table > and do some kind of reversed search to get the IP address out? ARP information is held in the routing table. Look at the output of netstat -arn and look for routes containing the L flag (LLINFO). If you need to walk through the routing table, look at how rtalloc() does it. 'struct rtentry' should be pretty self explanatory... BMS
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