DOCA FLOW pipe for getting/printing matched packet metadata

Hi there,
I am new to DOCA, and I managed to “copy-paste” together a simple code from sample applications and SDK docs that initializes everything properly (dpdk ports, doca flow, doca ports, etc.).
My intention is to have a simple application that prints out the 5-tuples crossing it.

I learned from the documentation that if we want to do anything with packets on a port, we have to create a DOCA FLOW PIPE. I managed to do this, set match to be on ipv4 packets.
However, even in sample apps like flow_modify_header, I observe that the code either directly matches on a header field, or just modify the header field via an action.
Is it possible to print out/get access to the packet metadata instead?

my pipe creation looks like this now:

static doca_error_t
create_simple_pipe(struct doca_flow_port *port, 
                   int port_id, 
                   struct doca_flow_pipe **pipe)
{
  /* create match struct */
  struct doca_flow_match match;
  /* create action struct */
  struct doca_flow_actions actions, *actions_arr[NB_ACTIONS_ARR];
  /* create monitor strut */
  struct doca_flow_monitor monitor;
  /* create fwd struct */
  struct doca_flow_fwd fwd;
  /* create pipe_cfg struct */
  struct doca_flow_pipe_cfg pipe_cfg;

  /* initialize these structs with 0s */
  memset(&match, 0, sizeof(match));
	memset(&actions, 0, sizeof(actions));
	memset(&monitor, 0, sizeof(monitor));
	memset(&fwd, 0, sizeof(fwd));
	memset(&pipe_cfg, 0, sizeof(pipe_cfg));

  /* ============== */
  /* configure pipe */
  /* ============== */
  /* attributes first */
  pipe_cfg.attr.name = "SIMPLE PIPE";
  pipe_cfg.attr.type = DOCA_FLOW_PIPE_BASIC; //this mean a flow pipe
  pipe_cfg.attr.domain = DOCA_FLOW_PIPE_DOMAIN_DEFAULT; // default pipe domain for action on ingress traffic
  pipe_cfg.attr.is_root = true; //determines whether the pipeline is root
  pipe_cfg.attr.enable_strict_matching = false; //if true, relaxed matching is disabled
  pipe_cfg.attr.nb_flows = 8000; //default value is 8k
  pipe_cfg.attr.nb_actions = NB_ACTIONS_ARR; //maximum number of DOCA Flow action array. Default is 1 if not set. mutually exclusive with nb_ordered_lists.
  pipe_cfg.attr.nb_ordered_lists = 0; // Number of ordered lists in the array. Default is 0. 
  pipe_cfg.attr.dir_info = DOCA_FLOW_DIRECTION_BIDIRECTIONAL; //default
  pipe_cfg.attr.miss_counter = true; //speaks for itself

  /* define which port is assigned to the pipe sia */
  pipe_cfg.port = port;

  /* add match to the pipe */
  pipe_cfg.match  = &match;
  //match.parser_meta.outer_l4_type = DOCA_FLOW_L4_META_TCP;
  match.outer.l3_type = DOCA_FLOW_L3_TYPE_IP4; //let's match on IPv4 packets (only)


  /* create monitor */
  pipe_cfg.monitor = &monitor;
  /* Packets matching the pipe entry are counted on the shared_counter_id.  */
  /* let's have non shared counters */
  monitor.meter_type = DOCA_FLOW_RESOURCE_TYPE_NON_SHARED;

  /* create actions */
  actions_arr[0] = &actions;
	pipe_cfg.actions = actions_arr;

  /* create fwd entry */
  fwd.type = DOCA_FLOW_FWD_PORT; //forward to another port
  fwd.port_id = port_id ^ 1; //forward to given output port

  /* call doca pipe creation with the config and return the created pipe sia */
  return doca_flow_pipe_create(&pipe_cfg, &fwd, NULL, pipe);

}

Where and how should I put a statement to get the packet metadata? Is it even feasible?

There is no ready to use sample for your purpose.

But you can check flow tracking,

https://docs.nvidia.com/doca/sdk/doca+flow+connection+tracking/index.html

I don’t think flow tracking helps me at all. This is just something like a monitoring pipe on steroids. That said, I still need to create rules I want to match on (6-tuples), then the pipes can keep track of those connections.

So even though DOCA can process packets fast in the hardware, the framework/sdk itself does not have access to the packet metadata they process?
I am not looking for a sample application to do that, I can write it on my own. But is there any feature for that?..it’s weird if not…

Hi Xiaofengl. I am also looking for something similar. I need the 5-tuple information to keep track of flows. Any leads? Maybe I am missing something.