From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Miller Date: Wed, 04 Mar 2015 19:51:08 +0000 Subject: Re: just the mark Message-Id: <54F7622C.5080306@computerisms.ca> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lartc@vger.kernel.org I have been reading man pages and googling and I am not finding understanding. maybe somebody can explain: under my mangle table (using iptables-restore to load): -A PREROUTING -p udp -m udp --dport 4500 -j MARK --set-mark 30 -A PREROUTING -s 192.168.171.0/24 -m mark ! --mark 30 -j MARK --set-mark 40 -A PREROUTING -m mark --mark 30 -j LOG --log-prefix vpnX30 -A PREROUTING -m mark --mark 40 -j LOG --log-prefix vpnX40 This logs packets with both marks. If I change the LOG target to POSTROUTING, like so: -A POSTROUTING -m mark --mark 30 -j LOG --log-prefix vpnX30 -A POSTROUTING -m mark --mark 40 -j LOG --log-prefix vpnX40 only packets with the mark 40 are logged. I think it should log both. If I consult the nfpacket flow chart, nat/PREROUTING comes after mangle/PREROUTING, and I cannot log packets with a mark of 30 there either. Traffic keeps flowing, so the packets themselves are not being dropped, but the mark apparently is not passed from the initial chain. Everything I have read indicates it should be. what could I have done (or not done) to make this happen? Or better yet, what should I be reading that would explain this? I get the feeling I am overlooking something really obvious... On 15-03-02 12:10 PM, Bob Miller wrote: > Hello, > > I read a few posts that it is possible to mark a packet with iptables, > and then shape it as it leaves on an ipsec tunnel. So far I am having > limited success with the idea. > > I am using libreswan with netkey. I tried marking the packets in > mangle/PREROUTING, but I had zero joy with that; I suspect that when the > kernel does its netkey magic the mark is lost. I tried marking at a > number of other spots in the nfpacket flow, I only got results at > mange/POSTROUTING. But it doesn't seem to grab all the packets. > > I have 6 remote users on the vpn, I give each of them a mark based on > the IP address they get, and I mark all non-vpn packets with a 7th mark. > I set up 7 classes to match each mark. I determine by the command > `watch -n 1 -d tc -s class show dev eth0` that some packets do go > through each class, but it is only a very small percentage of them > (after watching it for a while now I suspect it is initial syn packets). > The rest all go into the 7th non-vpn class, even though I can log the > packets marked to go to one of the vpn users. > > So I am wondering if I have missed a piece of the theory, or if what I > am trying to accomplish just isn't possible. Perhaps it would be better > to setup a class based on src/dst port 500, but I would like to > guarantee each vpn user a fair share of the limited bandwidth (which I > think pretty much requires a separate class for each user), and I am not > sure how that can be accomplished with dynamic remote addresses. > > comments or suggestions would be highly appreciated...