Netlink on DCE

[Matt Anonyme]

Hi,

I am trying to run  program under DCE that uses netlink to be notified of IP change events.

Right now it crashes:
====
0.600099s 1 DceTime:dce_gmtime(0x136ac80, 1)
0.600099s 1 Dce:dce_inet_ntop(0x136ac80, 1, 2, 0x7f87e1c68028, , 128)
0.600099s 1 Dce:dce_inet_ntop(0x136ac80, 1, 2, 0x7f87e1c68060, , 128)
0.600099s 1 Dce:dce_inet_ntop(0x136ac80, 1, 2, 0x7f87e1c68044, , 128)
0.600099s 1 ProcessUtils:UtilsAllocateFd(0x136ac80)
0.600099s 1 ProcessUtils:UtilsAllocateFd(): [DEBUG] Allocated fd=4
0.600099s 1 ProcessUtils:UtilsGetRealFilePath(0x136ac80, /proc/net/if_inet6)
0.600099s 1 ProcessUtils:UtilsGetVirtualFilePath(0x136ac80, /proc/net/if_inet6)
0.600099s 1 ProcessUtils:UtilsAllocateFd(0x136ac80)
0.600099s 1 ProcessUtils:UtilsAllocateFd(): [DEBUG] Allocated fd=4
assert failed. cond="m_ipv4Routing != 0", msg="Netlink Socket requires Ipv4DceRouting to be installed on the node", file=../netlink/netlink-socket.cc, line=277
terminate called without an active exception
====
While I could find the helper, I was hoping an example on how to install Ipv4DceRouting couild be pushed to DCE repository please ?

Best regards
Matt

[Richard]

I'm assuming you are missing the following;

LinuxStackHelper stack;
Ipv4DceRoutingHelper ipv4RoutingHelper;
stack.SetRoutingHelper (ipv4RoutingHelper);
stack.Install (nodes);

Without a sample of your code though, I can't be 100% sure, this is covered somewhere in the documentation/examples but I can't recall where exactly. 

[Matt]

Do you know if I must use the kernel or if there is a stub
implementation of Netlink (so that I can test without the kernel) ?

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[Richard]

As far as I know, you will need to use the kernel.

As a side note, I've had some issues with libnl inside DCE, libmnl has been much more stable. 

[Matt Anonyme]

I used you code but replaced  the LinuxStackHelper by InternetStackHelper and so far it looks ok.

Thanks a lot !

[Matt Anonyme]

Hi,

I am looking for the best way to debug netlink communications within DCE. I have got an error when calling dce_getifaddrs:
====
0.600022s 1 SimuFd:dce_recvmsg(0x8f6680, nodeId=, 1,  fd=, 5,  msg=, 0x7f82f1d2f170,  flags=, 0)
0.600022s 1 UnixDatagramSocketFd:DoRecvmsg(0x99c830, 0x8f6680, flags=, 0)
0.600022s 1 UnixDatagramSocketFd:DoRecvmsg(): [WARN ] msg_controllen < 0 , is that a problem ? <==== this is the error => returns -1  => error => dce_exit
0.600022s 1 SimuFd:dce_recvmsg(0x8f6680, nodeId=, 1,  fd=, 5,  msg=, 0x7f82f1d2f170,  flags=, 0)
0.600022s 1 UnixDatagramSocketFd:DoRecvmsg(0x99c830, 0x8f6680, flags=, 0)
0.600022s 1 UnixDatagramSocketFd:DoRecvmsg(): [WARN ] Kesako ?
1.6s 1 ProcessUtils:UtilsDoSignal(): [DEBUG] deliver signal=14
1.6s 1 SimuFd:dce_write(0x8f6680, 1, 1, 0x7f82e9b1b90d, 28)
1.6s 1 UnixFileFd:Write(0x8916d0, 0x8f6680, 0x7f82e9b1b90d, 28)
1.6s 1 UnixDatagramSocketFd:DoRecvmsg(): [WARN ] Empty packet
1.6s 1 DceNetdb:netlink_request(): [WARN ] read_len=-1 < 0
1.6s 1 DceNetdb:dce_getifaddrs(): [WARN ] Could not RTM_GETLINK.
====
Ideally I would like to export this to a pcap file and open it with wireshark dissector (https://www.wireshark.org/docs/dfref/n/netlink.html). Any idea on how to best tackle this pb please ?

Matt

[Mohammad Abu Shattal]

Hello All,
I'm trying to sniff packets over DCE using libpacp, the code is worknig fine my my native mahcine. Hever, I have this error message related to Netlink issue discussed here.

 
assert failed. cond="m_ipv4Routing != 0", msg="Netlink Socket requires Ipv4DceRouting to be installed on the node", file=../netlink/netlink-socket.cc, line=277
terminate called without an active exception

Fatal Python error: Aborted

I followed discussion above but recevied the follwoing error when I tried to setnetwork stack:

Code:

dceManager = ns.dce.DceManagerHelper()
dceManager.SetNetworkStack ("ns3::LinuxSocketFdFactory", "Library", ns.core.StringValue ("liblinux.so"))
stack  = LinuxStackHelper()
stack.Install (node);

Error:
dceManager.SetNetworkStack ("ns3::LinuxSocketFdFactory", "Library", ns.core.StringValue ("liblinux.so"))
AttributeError: 'dce.DceManagerHelper' object has no attribute 'SetNetworkStack'

Is this related to installation error? since it is supported by the API.
any suggestion to solve both problems?

Thanks .....

[Matt Anonyme]

Hi,

You can look in https://github.com/teto/ns-3-dce/blob/clock_support/myscripts/ntp/dce-ntpd.cc to setup "Ipv4DceRoutingHelper ipv4RoutingHelper;".
Beware that netlink support in DCE has some problems. I intend to send a patch this week but I dunno when.

Good luck to you

[Mohammad Abu Shattal]

Thank you Matt for your reply.

I reviewed the file you mentioned above, I'm scripting the ns3 code in python and the problem is that I couldn’t set the network stack.
Do you have any idea why the interpreter/compiler doesn't "see"  this function, although it sees all other DCE-application-manager-helper functions ..

Thank you ....

[Matt]

Sorry I don't use the bindings so I don't know why it doesn't appear.
My advice would be to look in wscript files and in the "bindings"
folder.

[Mohammad Abu Shattal]

Thank you for your reply. I will will follow your recommendation to see what's going on with wscript and Python binding.
Thanks