+++ /dev/null
-
-Advantage over current IMQ; cleaner in particular in in SMP;
-with a _lot_ less code.
-Old Dummy device functionality is preserved while new one only
-kicks in if you use actions.
-
-IMQ USES
---------
-As far as i know the reasons listed below is why people use IMQ.
-It would be nice to know of anything else that i missed.
-
-1) qdiscs/policies that are per device as opposed to system wide.
-IMQ allows for sharing.
-
-2) Allows for queueing incoming traffic for shaping instead of
-dropping. I am not aware of any study that shows policing is
-worse than shaping in achieving the end goal of rate control.
-I would be interested if anyone is experimenting.
-
-3) Very interesting use: if you are serving p2p you may wanna give
-preference to your own localy originated traffic (when responses come back)
-vs someone using your system to do bittorent. So QoSing based on state
-comes in as the solution. What people did to achive this was stick
-the IMQ somewhere prelocal hook.
-I think this is a pretty neat feature to have in Linux in general.
-(i.e not just for IMQ).
-But i wont go back to putting netfilter hooks in the device to satisfy
-this. I also dont think its worth it hacking dummy some more to be
-aware of say L3 info and play ip rule tricks to achieve this.
---> Instead the plan is to have a contrack related action. This action will
-selectively either query/create contrack state on incoming packets.
-Packets could then be redirected to dummy based on what happens -> eg
-on incoming packets; if we find they are of known state we could send to
-a different queue than one which didnt have existing state. This
-all however is dependent on whatever rules the admin enters.
-
-At the moment this function does not exist yet. I have decided instead
-of sitting on the patch to release it and then if theres pressure i will
-add this feature.
-
-What you can do with dummy currently with actions
---------------------------------------------------
-
-Lets say you are policing packets from alias 192.168.200.200/32
-you dont want those to exceed 100kbps going out.
-
-tc filter add dev eth0 parent 1: protocol ip prio 10 u32 \
-match ip src 192.168.200.200/32 flowid 1:2 \
-action police rate 100kbit burst 90k drop
-
-If you run tcpdump on eth0 you will see all packets going out
-with src 192.168.200.200/32 dropped or not
-Extend the rule a little to see only the ones that made it out:
-
-tc filter add dev eth0 parent 1: protocol ip prio 10 u32 \
-match ip src 192.168.200.200/32 flowid 1:2 \
-action police rate 10kbit burst 90k drop \
-action mirred egress mirror dev dummy0
-
-Now fire tcpdump on dummy0 to see only those packets ..
-tcpdump -n -i dummy0 -x -e -t
-
-Essentially a good debugging/logging interface.
-
-If you replace mirror with redirect, those packets will be
-blackholed and will never make it out. This redirect behavior
-changes with new patch (but not the mirror).
-
-What you can do with the patch to provide functionality
-that most people use IMQ for below:
-
---------
-export TC="/sbin/tc"
-
-$TC qdisc add dev dummy0 root handle 1: prio
-$TC qdisc add dev dummy0 parent 1:1 handle 10: sfq
-$TC qdisc add dev dummy0 parent 1:2 handle 20: tbf rate 20kbit buffer 1600 limit 3000
-$TC qdisc add dev dummy0 parent 1:3 handle 30: sfq
-$TC filter add dev dummy0 protocol ip pref 1 parent 1: handle 1 fw classid 1:1
-$TC filter add dev dummy0 protocol ip pref 2 parent 1: handle 2 fw classid 1:2
-
-ifconfig dummy0 up
-
-$TC qdisc add dev eth0 ingress
-
-# redirect all IP packets arriving in eth0 to dummy0
-# use mark 1 --> puts them onto class 1:1
-$TC filter add dev eth0 parent ffff: protocol ip prio 10 u32 \
-match u32 0 0 flowid 1:1 \
-action ipt -j MARK --set-mark 1 \
-action mirred egress redirect dev dummy0
-
---------
-
-
-Run A Little test:
-
-from another machine ping so that you have packets going into the box:
------
-[root@jzny action-tests]# ping 10.22
-PING 10.22 (10.0.0.22): 56 data bytes
-64 bytes from 10.0.0.22: icmp_seq=0 ttl=64 time=2.8 ms
-64 bytes from 10.0.0.22: icmp_seq=1 ttl=64 time=0.6 ms
-64 bytes from 10.0.0.22: icmp_seq=2 ttl=64 time=0.6 ms
-
---- 10.22 ping statistics ---
-3 packets transmitted, 3 packets received, 0% packet loss
-round-trip min/avg/max = 0.6/1.3/2.8 ms
-[root@jzny action-tests]#
------
-Now look at some stats:
-
----
-[root@jmandrake]:~# $TC -s filter show parent ffff: dev eth0
-filter protocol ip pref 10 u32
-filter protocol ip pref 10 u32 fh 800: ht divisor 1
-filter protocol ip pref 10 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
- match 00000000/00000000 at 0
- action order 1: tablename: mangle hook: NF_IP_PRE_ROUTING
- target MARK set 0x1
- index 1 ref 1 bind 1 installed 4195sec used 27sec
- Sent 252 bytes 3 pkts (dropped 0, overlimits 0)
-
- action order 2: mirred (Egress Redirect to device dummy0) stolen
- index 1 ref 1 bind 1 installed 165 sec used 27 sec
- Sent 252 bytes 3 pkts (dropped 0, overlimits 0)
-
-[root@jmandrake]:~# $TC -s qdisc
-qdisc sfq 30: dev dummy0 limit 128p quantum 1514b
- Sent 0 bytes 0 pkts (dropped 0, overlimits 0)
-qdisc tbf 20: dev dummy0 rate 20Kbit burst 1575b lat 2147.5s
- Sent 210 bytes 3 pkts (dropped 0, overlimits 0)
-qdisc sfq 10: dev dummy0 limit 128p quantum 1514b
- Sent 294 bytes 3 pkts (dropped 0, overlimits 0)
-qdisc prio 1: dev dummy0 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
- Sent 504 bytes 6 pkts (dropped 0, overlimits 0)
-qdisc ingress ffff: dev eth0 ----------------
- Sent 308 bytes 5 pkts (dropped 0, overlimits 0)
-
-[root@jmandrake]:~# ifconfig dummy0
-dummy0 Link encap:Ethernet HWaddr 00:00:00:00:00:00
- inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
- UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
- RX packets:6 errors:0 dropped:3 overruns:0 frame:0
- TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
- collisions:0 txqueuelen:32
- RX bytes:504 (504.0 b) TX bytes:252 (252.0 b)
------
-
-Dummy continues to behave like it always did.
-You send it any packet not originating from the actions it will drop them.
-[In this case the three dropped packets were ipv6 ndisc].
-
-cheers,
-jamal
git://git.onelab.eu / iproute2.git / blobdiff