Re: [PLUG] Raising the dead: proc filesystem

# ip ro get 8.8.8.8

8.8.8.8 via 10.250.52.1 dev bond0 src 10.250.52.164

cache mtu 1500 advmss 1460 hoplimit 64

Assuming 8.8.8.8 is not directly attached or has a more specific route, the IP following 'src' will be the IP address of the interface through which you route to your default gw. awk/sed/cut your way to only the IP.

On Jan 7, 2013, at 12:56 PM, Sam Gleske wrote:

Reference to an original thread "proc filesystem":
http://lists.netisland.net/archives/plug/plug-2002-12/msg00478.html

Has anyone found a decent way to do this outside of parsing ifconfig output? I've done it in a one liner here...
http://www.linuxquestions.org/questions/blog/sag47-492023/using-a-script-to-get-your-ip-address-35251/

Yet I've found that most times I'm able to reliably turn to the /proc filesystem for stuff like this. I'm just curious if anyone has found a decent way to do this since that thread was originally posted.

I wonder if parsing a combination of /proc/net/fib_trie and /proc/net/route would be useful in finding the IP address of the default route (which I would assume be the internet connected IP address). I found fib_trie by grep -irl my IP address through /proc. Here's some kernel documentation on fib_trie but there's nothing useful about using it for obtaining the IP address of the default route.

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=Documentation/networking/fib_trie.txt;h=0723db7f8495a1a0466ae06cd311c3e72ce24337;hb=HEAD

I look forward to discussing this.

SAM
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