LARTC - Jul 2002 - Oops with IMQ Ingress

Hi All,
	Is there any bug in Ingress for IMQ? I get Oops with following setup

/sbin/modprobe imq
iptables -I POSTROUTING -t mangle  -j IMQ
iptables -I PREROUTING -t mangle  -j IMQ
#Making imq0 enable
/sbin/ip link set imq0 up
#Adding root
/sbin/tc  qdisc del dev imq0 root

#Diverting unclassified traffic to default class.
/sbin/tc  qdisc add dev imq0 root handle 1: htb default 1

#Default traffic class
/sbin/tc  class add dev imq0 parent 1:0 classid 1:1 htb rate 100mbps

tc class add dev imq0 parent 1:2 classid 1:10 htb rate 50kbps ceil 50kbps
tc class add dev imq0 parent 1:2 classid 1:11 htb rate 50kbps ceil 50kbps

tc filter add dev imq0 protocol ip parent 1:0  prio 1 handle 800::1 u32
match ip dst 192.9.203.70 match ip sport 80 0xffff flowid 1:10
tc filter add dev imq0 protocol ip parent 1:0  prio 1 handle 800::3 u32
match ip src 192.9.203.139 match ip dport 80 0xffff flowid 1:10

	Now when I do http download my system crashes when download reaches
somewhere between 100K and 200K. Most surprising observation in this is
system crash happens only when I do download from simultanious connection
tool DAP (Download Accelarator Plus).
	I know in above setup one problem is there that a packet will get pass 2
from IMQ.
	I''m useing kernel-2.4.18 from redhat rpm and patched with
	imq-2.4.18.diff-10.txt, and htb3.6_2.4.17.diff

	Now let me clear my question why I asked Ingress... In above setup if i
remove "iptables -I PREROUTING -t mangle  -j IMQ" then no kernel oops.
Attechment is Oops on serial-console.

-- Sumit

Hi All,
	One more result with my setup. Here is my all command lines with more
details
my client IP is 192.9.203.70
IP on linux router	192.9.203.139 and xxx.xxx.xxx.xxx

# iptables -n -t nat -L -v
Chain PREROUTING (policy ACCEPT 245 packets, 42668 bytes)
 pkts bytes target     prot opt in     out     source
destination

Chain POSTROUTING (policy ACCEPT 14 packets, 1279 bytes)
 pkts bytes target     prot opt in     out     source
destination
   10   488 MASQUERADE  all  --  *      eth1    192.9.203.0/24
0.0.0.0/0

Chain OUTPUT (policy ACCEPT 19 packets, 1963 bytes)
 pkts bytes target     prot opt in     out     source
destination


# iptables -n -t mangle -L -v
Chain PREROUTING (policy ACCEPT 6917 packets, 4711K bytes)
 pkts bytes target     prot opt in     out     source
destination
   12   569 IMQ        all  --  *      *       0.0.0.0/0
0.0.0.0/0          IMQ: todev 0

Chain INPUT (policy ACCEPT 1419 packets, 118K bytes)
 pkts bytes target     prot opt in     out     source
destination

Chain FORWARD (policy ACCEPT 5356 packets, 4575K bytes)
 pkts bytes target     prot opt in     out     source
destination

Chain OUTPUT (policy ACCEPT 824 packets, 67098 bytes)
 pkts bytes target     prot opt in     out     source
destination

Chain POSTROUTING (policy ACCEPT 6191 packets, 4644K bytes)
 pkts bytes target     prot opt in     out     source
destination
 5779 4600K IMQ        all  --  *      *       0.0.0.0/0
0.0.0.0/0          IMQ: todev 0

# sh /root/show_tc.sh
############################################################################
########################
                                                        Qdisciplines
############################################################################
########################
qdisc htb 1: r2q 10 default 1 direct_packets_stat 0
 Sent 2185158 bytes 2835 pkts (dropped 1, overlimits 3168)


############################################################################
########################
                                                        Classes
############################################################################
########################
class htb 1:11 root prio 0 quantum 5120 rate 400Kbit ceil 400Kbit burst
2111b/8 mpu 0b cburst 2111b/8 mpu 0b level 0 buffer [000119fb] cbuffer
[000119fb]
 Sent 0 bytes 0 pkts (dropped 0, overlimits 0)
 lended: 0 borrowed: 0 giants: 0
 tokens: 72187 ctokens: 72187

class htb 1:1 root prio 0 quantum 200000 rate 800Mbit ceil 800Mbit burst
1050044b/8 mpu 0b cburst 1050044b/8 mpu 0b level 0 buffer [00004476] cbuffer
[00004476]
 Sent 40014 bytes 482 pkts (dropped 0, overlimits 0)
 rate 100bps 1pps
 lended: 482 borrowed: 0 giants: 0
 tokens: 17526 ctokens: 17526

class htb 1:10 root prio 0 quantum 5120 rate 400Kbit ceil 400Kbit burst
2111b/8 mpu 0b cburst 2111b/8 mpu 0b level 0 buffer [000119fb] cbuffer
[000119fb]
 Sent 2145144 bytes 2353 pkts (dropped 1, overlimits 0)
 lended: 2353 borrowed: 0 giants: 0
 tokens: 70548 ctokens: 70548

############################################################################
########################
                                                        Filters
############################################################################
########################
filter parent 1: protocol ip pref 1 u32
filter parent 1: protocol ip pref 1 u32 fh 800:[80000000]  ht divisor 1
filter parent 1: protocol ip pref 1 u32 fh 800::1[80000001]  order 1 key ht
800 bkt 0 flowid 1:10
  match c009cb46/ffffffff at 16
  match 00500000/ffff0000 at 20
filter parent 1: protocol ip pref 1 u32 fh 800::3[80000003]  order 3 key ht
800 bkt 0 flowid 1:10
  match c009cb46/ffffffff at 12
  match 00000050/0000ffff at 20


	This time Oops trace is different then previous. But similarity is that it
can be simulated by placing simply one entry into iptables i.e iptables -t
mangle -I PREROUTING -j IMQ and avoided by not having above entry.
	I know again filter 800::3 is not proper and it does not satisfy my
purpose. Insteed of specifying Public-IP, I made mistake of placing
client-ip and found some bug.

-- Sumit