> -----Original Message----- > From: users [mailto:users-bounces at dpdk.org] On Behalf Of Gadre Nayan > Sent: Monday, July 18, 2016 4:42 PM > To: users at dpdk.org > Subject: [dpdk-users] Tracking pipeline ports. > > Hi, > > I wanted to understand the purpose of the f_track function. > > In the IP_pipeline example there are 2 instances where the f_track is used. > > 1. pipeline_firewall: > static int pipeline_firewall_track(void *pipeline, __rte_unused uint32_t > port_in, > uint32_t *port_out) > { > struct pipeline *p = (struct pipeline *) pipeline; > > /* Check input arguments */ > if ((p == NULL) || > (port_in >= p->n_ports_in) || > (port_out == NULL)) > return -1; > > if (p->n_ports_in == 1) { > *port_out = 0; > return 0; > } > > return -1; > } > > 2. Passthrough: > > static int > pipeline_passthrough_track(void *pipeline, uint32_t port_in, uint32_t > *port_out) { > struct pipeline *p = (struct pipeline *) pipeline; > > /* Check input arguments */ > if ((p == NULL) || > (port_in >= p->n_ports_in) || > (port_out == NULL)) > return -1; > > *port_out = port_in / p->n_ports_in; > return 0; > }
The f_track function is used in all the pipeline instances. All pipeline instances except passthrough pipeline implements default version of the f_track function. The pipelines such as pass-through allows tracking to be performaned through them becasue of straightforward connections between their input and output ports, while pipelines like flow-classifications, firewall fails the tracking because of the dependency on the table rule set. > 1. What is a actual use of this function ? > Quoting the documentation: > "In some cases, it is useful for a pipeline instance to get application level > information related to pipeline connectivity, such as to identify the output > link (e.g. physical NIC port) where one of its output ports connected, either > directly or indirectly by traversing other pipeline instances." This function is implemented as the part of tracking mechanism for identifying the physical nic port where a specific output ports of the routing pipeline are eventually connected. Tracking could involve traversing the other intermediate pipelines before actually getting to physical nic ports. As a result of tracking, routing pipeline can use the real MAC addresses of the network interfaces instead of using hardcoded default value for building the table entries . Furthermore, It also adds support for automatic route updates (add/remove routing entries) when linked physical NIC ports change their state (up/down). > 2. The 1st condition check remains same in both. But in pass-through > port_out is assigned some value. what does this mean ? These are older version of the functions, please check with latest code. Jasvinder
