TDA4VM-Q1: iptables forward failed

wells xiong

Part Number: TDA4VM-Q1
Other Parts Discussed in Thread: TDA4VM

Tool/software:

The version of linux SDK：ti-processor-sdk-linux-j7-evm-08_06_01_02, our board diagram is shown in the dashed box above, 4×T1 is used for interface of four lidar, and I can get point- cloud of each lidar (by tcpdump -i eth1/ eth2/ eth3/ eth4 src net 192.168.xx.100, xx=2/ 3/ 4/ 5), but when I try to forward these lidar’s point- cloud to eth0 (IP: 192.168.1.100 ) by iptables:

I found that: FORWARD failed. (0 packets, 0 bytes)

By the way, the Lidar work as udp client (Continuously sending data), I can capture point-cloud on TDA4vm:

However, the Host which is connected to eth0 of TDA4vm can not received point-cloud.

1 month ago

0 Tanmay Patil 1 month ago

TI__Mastermind 30510 points

Hi,

Can you first make sure that the modules are loaded by running the command "lsmod"

Regards,
Tanmay

0 wells xiong 1 month ago in reply to Tanmay Patil

Prodigy 60 points

I am sure that the modules were loaded.

Then，I do further testing：

firstly，I removed the lidar from eth1 of TDA4vm，and connected a testing compute to eth1 of TDA4vm；

secondly，tried to transmit UDP packets from the testing computer to eth1 of TDA4vm, and executed these commands as follows(the same as these commands when I tried to test point-cloud of lidar).

iptables -t nat -A PREROUTING -d 192.168.2.100 -j DNAT --to-destination 192.168.1.120
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT

The testing result was correspondent with I thought: The Host which is connected to eth0 of TDA4vm can not received any packet. But, I tried to transmit UDP packets from the Host which is connected to eth0 of TDA4, and modified command as follows:

iptables -t nat -A PREROUTING -d 192.168.1.100 -j DNAT --to-destination 192.168.2.144
iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT
iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT

Surprisingly, the testing computer which is connected to eth1 of TDA4vm can receive UDP packets.