i386/147245: dummynet skip traffic over configured limit with net.inet.ip.dummynet.io_fast:1

Mon May 31 14:20:06 UTC 2010

>Number:         147245
>Category:       i386
>Synopsis:       dummynet skip traffic over configured limit with net.inet.ip.dummynet.io_fast:1
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon May 31 14:20:04 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     napTu
>Release:        8.0
>Organization:
icene
>Environment:
FreeBSD router5 8.0-STABLE FreeBSD 8.0-STABLE #1: Fri May  7 02:03:26 UTC 2010     root@:/buildscripts/frenzybuild/build/buildscripts/frenzybuild/src/sys/FRENZY  i386
>Description:
My example pipe configuration is:

# ipfw pipe 45795 show
45795:  11.992 Mbit/s    0 ms burst 0
q176867  50 sl. 0 flows (1 buckets) sched 111331 weight 0 lmax 0 pri 0 droptail
 sched 111331 type FIFO flags 0x0 0 buckets 0 active

# ipfw list 28795
28795 pipe 45795 ip from not 192.168.0.0/16,10.0.0.0/8,172.0.0.0/8 to 192.168.9.33 out via em0

# ipfw list 30019 
30019 allow ip from any to 192.168.9.33 out via em0

net.inet.ip.fw.one_pass: 0
net.inet.ip.dummynet.io_fast:1

I detect two variants when traffic is greater that limit on the pipe.

1. when pipe speed is greater 11.999Mbit/s, for example when bw is 12.000Mbit/s, no traffic limit happen.

2. when traffic is udp and goes to one port and one ip from multiple sources.
trafshow output:
Source                          Destination                     Protocol     Size         CPS
&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;&#9472;
95.215.165.200,62844            192.168.8.13,43546              udp          23607K       2194K
109.87.126.156,55629            192.168.8.13,43546              udp          10873K       1138K
85.198.145.111,32100            192.168.8.13,43546              udp          767K         32K
78-137-18-109.dynamic-ppp,15833 192.168.8.13,43546              udp          667K         47K

pipe config is

28521 pipe 45521 ip from not 192.168.0.0/16,10.0.0.0/8,172.0.0.0/8 to 192.168.8.13 out via em0
32349 allow ip from any to 192.168.8.13 out via em0

45521:  11.992 Mbit/s    0 ms burst 0
q176593  50 sl. 0 flows (1 buckets) sched 111057 weight 0 lmax 0 pri 0 droptail
 sched 111057 type FIFO flags 0x0 0 buckets 0 active

>How-To-Repeat:
as descibed in full description
>Fix:
set net.inet.ip.dummynet.io_fast to 0

>Release-Note:
>Audit-Trail:
>Unformatted: