[ovs-discuss] Defined GRE key value to a GRE interface corrupted to the outgoing packets when csum value is true

[Christos Argyropoulos]

1)Description: Defined GRE key value to a GRE interface corrupted to the 
outgoing packets when csum value is true

2)Version: ovs-vswitchd (Open vSwitch) 1.4.90, Compiled Dec 28 2011 
15:07:59, OpenFlow versions 0x1:0x1

3)Git commit number: git rev-parse HEAD 
deedf7e78b249383d6f7b385f9d04e08e33d0e3f

4)Local Patches: None

5)/proc/version: Linux version 2.6.38-8-server (buildd at allspice) (gcc 
version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu3) ) #42-Ubuntu SMP

6)The machine is a virtual machine running on VMware ESXi Hypervisor

7)uname -a: Linux ovs1 2.6.38-8-server #42-Ubuntu SMP Mon Apr 11 
03:49:04 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

8)csum=false, defined gre key value is passed correctly to the GRE 
headers (check out the attached file "csum_disabled_proper_gre_value.txt")

Port "gre100_2"
             tag: 2830
             Interface "gre100_2"
                 type: gre
                 options: {csum="false", key="0x0000ffff", 
remote_ip="147.102.13.59"}

9)csum=true, defined gre key value is corrupted to the GRE headers 
(check out the attached file "csum_enabled_corrupted_gre_value.txt")

Port "gre100_2"
             tag: 2830
             Interface "gre100_2"
                 type: gre
                 options: {csum="false", key="0x0000ffff", 
remote_ip="147.102.13.59"}

10)Details: As you can see from the above port configuration in both 
cases the key value is the same. From the packet capture you can see 
that when the csum
flag is set the gre key value is 0x3077ffff instead of 0x0000ffff. 
Moreover i noticed that the ckecksum value is 0x0000 [correct] that does 
not make sense.


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