netdev - Re: libpcap and tc filters

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1309870021.1765.41.camel@mojatatu>
Date:	Tue, 05 Jul 2011 08:47:01 -0400
From:	jamal <hadi@...erus.ca>
To:	Adam Katz <adamkatz0@...il.com>
Cc:	netdev@...r.kernel.org
Subject: Re: libpcap and tc filters

On Tue, 2011-07-05 at 06:56 -0400, jamal wrote:

> I downloaded tcpreplay and reproduced the issue with your rules.
> Will look into it..

Ok - found out whats going on. 
tcprelay sendpacket_open_pf() does bind to ETH_P_ALL.
You are sending IP packets (the name tcpreplay is misleading,
this thing replays anything). 
Your filters are for ip packets as in:
---
sudo tc filter add dev eth0 protocol ip parent 1: prio 1 u32 match ip
dport 22 0xffff flowid 1:1
---

You have two options:

1) If you change that to capture ETH_P_ALL it works.
i.e

---
sudo tc filter add dev eth0 protocol all parent 1: prio 1 u32 match ip
dport 22 0xffff flowid 1:1
---

Of course this is nasty if you are in a busy network, because _all_
packets not just ip will look at your filters. If it is just an
experimental setup, it may be a non-issue

2) Change tcpreplay to take an additional option so it binds to 
ETH_P_IP (and default stays as is today). The authors of the app
may not like that option - but it is sensible if you know you are
replaying ip packets.

cheers,
jamal

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html