======talk:ifb======

I do not have ifb installed on my kernel and i do not know how to install. There is no web where i can find information. Can anybody help me?

Answer: It is part of the standard kernel starting with 2.6.12.
To enable it you need to enable:

  *  NET_SCHED
<code> Networking -->
   Networking Options -->
     QOS and fair scheduling --></code>

  *  NET_CLS_ACT
<code>     QOS and fair scheduling -->
          Actions</code>

  *  IFB
<code>     Device Drivers -->
       Network devices -->
         IFB</code>
=====  cant redirect traffic to the ifb =====

I've set up ifb0:

----
<code>tc -s class show dev ifb0</code>
<code>class htb 1:10 parent 1:1 leaf 10: prio 1 rate 80000bit ceil 160000bit burst 1700b cburst 1800b
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
lended: 0 borrowed: 0 giants: 0
tokens: 170000 ctokens: 90000</code>
<code>class htb 1:1 root rate 624000bit ceil 624000bit burst 2379b cburst 2379b
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
lended: 0 borrowed: 0 giants: 0
tokens: 30512 ctokens: 30512</code>
<code>class htb 1:20 parent 1:1 leaf 20: prio 2 rate 80000bit ceil 160000bit burst 1700b cburst 1800b
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
lended: 0 borrowed: 0 giants: 0
tokens: 170000 ctokens: 90000</code>
<code>class htb 1:30 parent 1:1 leaf 30: prio 3 rate 240000bit ceil 560000bit burst 1899b cburst 2299b
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
lended: 0 borrowed: 0 giants: 0
tokens: 63333 ctokens: 32857</code>
<code>class htb 1:40 parent 1:1 prio 4 rate 24000bit ceil 400000bit burst 1629b cburst 2100b
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
lended: 0 borrowed: 0 giants: 0
tokens: 543333 ctokens: 42000</code>
<code>class htb 1:41 parent 1:1 leaf 41: prio 5 rate 16000bit ceil 400000bit burst 1620b cburst 2100b
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
lended: 0 borrowed: 0 giants: 0
tokens: 810000 ctokens: 42000</code>
<code>class htb 1:42 parent 1:1 leaf 42: prio 6 rate 8000bit ceil 160000bit burst 1610b cburst 1800b
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
lended: 0 borrowed: 0 giants: 0
tokens: 1610000 ctokens: 90000</code>

\\ 
<code>ifconfig ifb0
ifb0      Link encap:Ethernet  HWaddr 9A:AE:D9:C1:89:E7
         UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
         RX packets:0 errors:0 dropped:0 overruns:0 frame:0
         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:32
         RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)</code>

----

\\ 
I have recent kernel and iproute2:

----
<code>emerge -pv iproute2
These are the packages that would be merged, in order:
Calculating dependencies... done!
[ebuild   R   ] sys-apps/iproute2-2.6.20.20070313  USE="berkdb -atm -minimal" 0 kB
Total: 1 package (1 reinstall), Size of downloads: 0 kB</code>

\\ 
<code>uname -a
Linux titan 2.6.21-gentoo-r3 #1 Mon Jul 2 03:43:22 CEST 2007 x86_64 AMD Athlon(tm) 64 Processor 3000+ AuthenticAMD GNU/Linux</code>

----

and mirred module is loaded:

\\ 

----
<code>lsmod
Module                  Size  Used by
act_mirred              4832  0
ifb                     4168  0
it87                   22224  0
hwmon_vid               3648  1 it87
i2c_isa                 5120  1 it87
xt_state                2688  5
ipt_REDIRECT            2240  3</code>

----

\\ 
but when I try to redirect traffic to it I get:

\\ 

----
<code>tc filter add dev eth2 parent ffff: protocol ip prio 30 u32 match ip src 0.0.0.0/0 action mirred egress redirect dev ifb0
Action 4 device ifb0 ifindex 6
RTNETLINK answers: Invalid argument
We have an error talking to the kernel</code>

----
=====  What is "redirect"? =====

I've read all the examples and I can see that IFB magic (for shaping) happens with:
<code>action mirred egress redirect dev ifb0</code>

Please could someone explain what redirect means, how redirecting to an IFB device shapes incoming traffic, what mirred is, etc?

Thanks