Unable to set TCP flags

[pchaseh]

Hi,

I'm using this project with packets generated from an Lua script which appears as follows:

package.path = package.path ..";?.lua;test/?.lua;app/?.lua;"

require "Pktgen"

local seq_table = {
     ["eth_dst_addr"] = "xx:xx:xx:xx:xx:xx",
     ["eth_src_addr"] = "yy:yy:yy:yy:yy:yy",
     ["ip_dst_addr"] = "1.2.3.4",
     ["ip_src_addr"] = "4.3.2.1",
     ["sport"] = 9,
     ["dport"] = 10,
     ["ethType"] = "ipv4",
     ["ipProto"] = "tcp",
     ["vlanid"] = 11,
     ["pktSize"] = 128,
     ["tcp_flags"] = 2
 };
 pktgen.seqTable(0, "all", seq_table);
 pktgen.vlan("all", "enable");
 pktgen.set("all", "seqCnt", 1);

When I launch pktgen and run it (via script myscript.lua then start all) I'm seeing the generated TCP traffic still use DEFAULT_TCP_FLAGS (ACK) instead of the tcp_flags value. I'm not sure what representation it expects, but I've tried both the numerical value for the SYN flag (2) as well as "S" to no avail. Additionally, running set all tcp flag set syn yields no difference. When I recompile pktgen with DEFAULT_TCP_FLAGS set to SYN_FLAG it works, so it appears as if never overwrites the default value.

pktgen version: 24.07.0

[KeithWiles]

It looks like a bug, I see why it is not working and I will look at it this weekend.

[KeithWiles]

I think I have the TCP flags working, please give the fix-tcp-flags branch a try and let me know.

[pchaseh]

Thanks Keith, seems to be working a first glance, however I'm getting this crash when loading Lua scripts on the fix-tcp-flags branch when the tcp_flags field isn't specified. Likewise, if I change the IP protocol to UDP, it still occurs. I've verified that in switching over to main, recompiling, and relaunching pktgen, I don't see this problem

Note that my script doesn't start sending packets (that's left to the user), so appears to be an issue during packet initialization

[KeithWiles]

OK thanks, please try the fixes-for-release branch if you have time. It most likely will not fix this problem and it will take me a few days to be able to look into the problem.