CT mark is not realized correctly

[hongliangl]

Describe the bug
CT mark defined in pkg/agent/openflow/field.go like NotServiceCTMark = binding.NewOneBitZeroCTMark(4) is used in a flow as the following:

ConntrackCommitTable.ofTable.BuildFlow(priorityNormal).
		Cookie(cookieID).
		MatchProtocol(ipProtocol).
		MatchCTStateNew(true).
		MatchCTStateTrk(true).
		MatchCTMark(NotServiceCTMark).
		Action().CT(true, ConntrackCommitTable.GetNext(), f.ctZones[ipProtocol], f.ctZoneSrcField).
		MoveToCtMarkField(PktSourceField, ConnSourceCTMarkField).
		CTDone().
		Done(),

The flow should to be like the following:

cookie=0xf010000000000, table=28, priority=200,ct_mark=0x0/0x10, ct_state=+new+trk,ip actions=ct(commit,table=29,zone=65520,exec(move:NXM_NX_REG0[0..3]->NXM_NX_CT_MARK[0..3]))

But it is:

cookie=0xf010000000000, table=28, priority=200,ct_state=+new+trk,ip actions=ct(commit,table=29,zone=65520,exec(move:NXM_NX_REG0[0..3]->NXM_NX_CT_MARK[0..3]))

As a result, the CT mark is not realized in the flow.

[wenyingd]

Hi @hongliangl , this is introduced by an issue in the dependent library ofnet. I have made a fix and it is merged now (antrea-io/ofnet#30). Please update go.mod with ofnet version 0.5.7+, and the fix would be involved.