RTOS/PROCESSOR-SDK-AM437X: UDP packet routing

Marcio Borges

Expert 1950 points

Tool/software: TI-RTOS

I am repeating my question on thread https://e2e.ti.com/support/arm/sitara_arm/f/791/t/702277 , because I haven´t got an answer.

How to configure NDK to route UDP packets from eth0 to eth1 and vice-versa? Is it possible?

I need to forward UDP packets received on eth0 to eth1 (CPSW Ethernet interfaces) and vice-versa.

eth0 is configured with static IP address 192.168.0.1 and sub-net mask 255.255.0.0 and eth1 is configured with static IP address 192.169.0.1 and sub-net mask 255.255.0.0.

Installed itens:
CCS 7.2
GCC ARM Compiler 4.9.3
processor_sdk_rtos_am437x 4.00.00.04

ndk_2_26_00_08
am437x PDK v1.0.7
bios 6.46.05.55
xdctools 3.32.02.25_core

regards,

Marcio.

over 7 years ago

0 Biser Gatchev-XID over 7 years ago

TI__Guru**** 393215 points

The RTOS team have been notified. They will respond here.

0 Garrett Ding over 7 years ago in reply to Biser Gatchev-XID

TI__Mastermind 43296 points

Hi Marcio.

I could not replicate the issue you described and was out of office for a few weeks since then, will continue to work on it and update you if any progress.

Regards, Garrett

0 Garrett Ding over 7 years ago in reply to Garrett Ding

TI__Mastermind 43296 points

Marcio,

Still I can only ping eth0 from PC1 and eth1 from PC2 with the following configuration as shown in your project. I have reached out NDK team to see if any insight to the routing issue...

Regards, Garrett

0 Garrett Ding over 7 years ago in reply to Garrett Ding

TI__Mastermind 43296 points

Marcio.

One thought is the NAT that needs to be set up in the case.

PC1 and NDK eth0 both have addresses on the network 192.168.0.0, which is a private network. As such, packets from that private network can’t be forwarded to an external public network (in this case, 192.169.0.0).

This thread may help configure NAT - e2e.ti.com/.../518779

Regards,
Garrett

0 Marcio Borges over 7 years ago in reply to Garrett Ding

Expert 1950 points

Hi Garret,

You are correct. "169" is defined as "public IP address" and 168 is "private IP address". NDK has a NAT module, which is used by the stack when routing, to translate the IP address of a packet to/from a private LAN from/to a public WAN.

I thing we mislead about the IP addresses. I believe we want to route packets on a private network. I´ll check with the system team.

Suppose we replace all 192.169.0.x by 192.168.1.x and all subnet masks to 255.255.255.0 (NDK specification says that eth0 an eth1 must be on different subnets). If we just configure the second route as you did, would NDK route the packet?

regards,

0 Garrett Ding over 7 years ago in reply to Marcio Borges

TI__Mastermind 43296 points

Marcio,

If you want to route packets on a private network, it's true that you don't need set up NAT, and NDK should route the packet.

Regards,
Garrett

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RTOS/PROCESSOR-SDK-AM437X: UDP packet routing