.. BSD LICENSE Copyright(c) 2010-2014 Intel Corporation. All rights reserved. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Intel Corporation nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .. _spp_vf_explain_functions: Explanation =========== The following sections provide some explanation of the code. Initializing ------------ A manager thread of ``spp_vf`` initialize eal by ``rte_eal_init()``. Then each of component threads are launched by ``rte_eal_remote_launch()``. .. code-block:: c /* spp_vf.c */ int ret_dpdk = rte_eal_init(argc, argv); /* Start worker threads of classifier and forwarder */ unsigned int lcore_id = 0; RTE_LCORE_FOREACH_SLAVE(lcore_id) { rte_eal_remote_launch(slave_main, NULL, lcore_id); } Main function of slave thread ----------------------------- ``slave_main()`` is called from ``rte_eal_remote_launch()``. It call ``spp_classifier_mac_do()`` or ``spp_forward()`` depending on the component command setting. ``spp_classifier_mac_do()`` provides function for classifier, and ``spp_forward()`` provides forwarder and merger. .. code-block:: c /* spp_vf.c */ RTE_LOG(INFO, APP, "Core[%d] Start.\n", lcore_id); set_core_status(lcore_id, SPP_CORE_IDLE); while ((status = spp_get_core_status(lcore_id)) != SPP_CORE_STOP_REQUEST) { if (status != SPP_CORE_FORWARD) continue; if (spp_check_core_index(lcore_id)) { /* Setting with the flush command trigger. */ info->ref_index = (info->upd_index+1) % SPP_INFO_AREA_MAX; core = get_core_info(lcore_id); } for (cnt = 0; cnt < core->num; cnt++) { if (spp_get_component_type(lcore_id) == SPP_COMPONENT_CLASSIFIER_MAC) { /* Classifier loops inside the function. */ ret = spp_classifier_mac_do(core->id[cnt]); break; } /* * Forward / Merge returns at once. * It is for processing multiple components. */ ret = spp_forward(core->id[cnt]); if (unlikely(ret != 0)) break; } if (unlikely(ret != 0)) { RTE_LOG(ERR, APP, "Core[%d] Component Error. (id = %d)\n", lcore_id, core->id[cnt]); break; } } set_core_status(lcore_id, SPP_CORE_STOP); RTE_LOG(INFO, APP, "Core[%d] End.\n", lcore_id); Data structure of classifier table ---------------------------------- ``spp_classifier_mac_do()`` lookup following data defined in ``classifier_mac.c``, when it process the packets. Configuration of classifier is stored in the structure of ``classified_data``, ``classifier_mac_info`` and ``classifier_mac_mng_info``. The ``classified_data`` has member variables for expressing the port to be classified, ``classifier_mac_info`` has member variables for determining the direction of packets such as hash tables. Classifier manages two ``classifier_mac_info``, one is for updating by commands, the other is for looking up to process packets. Then the ``classifier_mac_mng_info`` has two(``NUM_CLASSIFIER_MAC_INFO``) ``classifier_mac_info`` and index number for updating or reference. .. code-block:: c /* classifier_mac.c */ /* classified data (destination port, target packets, etc) */ struct classified_data { /* interface type (see "enum port_type") */ enum port_type iface_type; /* index of ports handled by classifier */ int iface_no; /* id for interface generated by spp_vf */ int iface_no_global; /* port id generated by DPDK */ uint16_t port; /* the number of packets in pkts[] */ uint16_t num_pkt; /* packet array to be classified */ struct rte_mbuf *pkts[MAX_PKT_BURST]; }; /* classifier information */ struct classifier_mac_info { /* component name */ char name[SPP_NAME_STR_LEN]; /* hash table keeps classifier_table */ struct rte_hash *classifier_table; /* number of valid classification */ int num_active_classified; /* index of valid classification */ int active_classifieds[RTE_MAX_ETHPORTS]; /* index of default classification */ int default_classified; /* number of transmission ports */ int n_classified_data_tx; /* receive port handled by classifier */ struct classified_data classified_data_rx; /* transmission ports handled by classifier */ struct classified_data classified_data_tx[RTE_MAX_ETHPORTS]; }; /* classifier management information */ struct classifier_mac_mng_info { /* classifier information */ struct classifier_mac_info info[NUM_CLASSIFIER_MAC_INFO]; /* Reference index number for classifier information */ volatile int ref_index; /* Update index number for classifier information */ volatile int upd_index; }; Packet processing in classifier ------------------------------- In ``spp_classifier_mac_do()``, it receives packets from rx port and send them to destinations with ``classify_packet()``. ``classifier_info`` is an argument of ``classify_packet()`` and is used to decide the destinations. .. code-block:: c /* classifier_mac.c */ while (likely(spp_get_core_status(lcore_id) == SPP_CORE_FORWARD) && likely(spp_check_core_index(lcore_id) == 0)) { /* change index of update side */ change_update_index(classifier_mng_info, id); /* decide classifier information of the current cycle */ classifier_info = classifier_mng_info->info + classifier_mng_info->ref_index; classified_data_rx = &classifier_info->classified_data_rx; classified_data_tx = classifier_info->classified_data_tx; /* drain tx packets, if buffer is not filled for interval */ cur_tsc = rte_rdtsc(); if (unlikely(cur_tsc - prev_tsc > drain_tsc)) { for (i = 0; i < classifier_info->n_classified_data_tx; i++) { if (likely(classified_data_tx[i].num_pkt == 0)) continue; RTE_LOG(DEBUG, SPP_CLASSIFIER_MAC, "transmit packets (drain). " "index=%d, " "num_pkt=%hu, " "interval=%lu\n", i, classified_data_tx[i].num_pkt, cur_tsc - prev_tsc); transmit_packet(&classified_data_tx[i]); } prev_tsc = cur_tsc; } if (classified_data_rx->iface_type == UNDEF) continue; /* retrieve packets */ n_rx = rte_eth_rx_burst(classified_data_rx->port, 0, rx_pkts, MAX_PKT_BURST); if (unlikely(n_rx == 0)) continue; #ifdef SPP_RINGLATENCYSTATS_ENABLE if (classified_data_rx->iface_type == RING) spp_ringlatencystats_calculate_latency( classified_data_rx->iface_no, rx_pkts, n_rx); #endif /* classify and transmit (filled) */ classify_packet(rx_pkts, n_rx, classifier_info, classified_data_tx); } Classifying the packets ----------------------- ``classify_packet()`` uses hash function of DPDK to determine destination. Hash has MAC address as Key, it retrieves destination information from destination MAC address in the packet. .. code-block:: c for (i = 0; i < n_rx; i++) { eth = rte_pktmbuf_mtod(rx_pkts[i], struct ether_hdr *); /* find in table (by destination mac address)*/ ret = rte_hash_lookup_data(classifier_info->classifier_table, (const void *)ð->d_addr, &lookup_data); if (ret < 0) { /* L2 multicast(include broadcast) ? */ if (unlikely(is_multicast_ether_addr(ð->d_addr))) { RTE_LOG(DEBUG, SPP_CLASSIFIER_MAC, "multicast mac address.\n"); handle_l2multicast_packet(rx_pkts[i], classifier_info, classified_data); continue; } /* if no default, drop packet */ if (unlikely(classifier_info->default_classified == -1)) { ether_format_addr(mac_addr_str, sizeof(mac_addr_str), ð->d_addr); RTE_LOG(ERR, SPP_CLASSIFIER_MAC, "unknown mac address. " "ret=%d, mac_addr=%s\n", ret, mac_addr_str); rte_pktmbuf_free(rx_pkts[i]); continue; } /* to default classified */ RTE_LOG(DEBUG, SPP_CLASSIFIER_MAC, "to default classified.\n"); lookup_data = (void *)(long)classifier_info-> default_classified; } /* * set mbuf pointer to tx buffer * and transmit packet, if buffer is filled */ push_packet(rx_pkts[i], classified_data + (long)lookup_data); } Packet processing in forwarder and merger ----------------------------------------- Configuration data for forwarder and merger is stored as structured tables ``forward_rxtx``, ``forward_path`` and ``forward_info``. The ``forward_rxtx`` has two member variables for expressing the port to be sent(tx) and to be receive(rx), ``forward_path`` has member variables for expressing the data path. Like ``classifier_mac_info``, ``forward_info`` has two tables, one is for updating by commands, the other is for looking up to process packets. .. code-block:: c /* spp_forward.c */ /* A set of port info of rx and tx */ struct forward_rxtx { struct spp_port_info rx; /* rx port */ struct spp_port_info tx; /* tx port */ }; /* Information on the path used for forward. */ struct forward_path { char name[SPP_NAME_STR_LEN]; /* component name */ volatile enum spp_component_type type; /* component type */ int num; /* number of receive ports */ struct forward_rxtx ports[RTE_MAX_ETHPORTS]; /* port used for transfer */ }; /* Information for forward. */ struct forward_info { volatile int ref_index; /* index to reference area */ volatile int upd_index; /* index to update area */ struct forward_path path[SPP_INFO_AREA_MAX]; /* Information of data path */ }; Forward and merge the packets ----------------------------- ``spp_forward()`` defined in ``spp_forward.c`` is a main function for both forwarder and merger. ``spp_forward()`` simply passes packet received from rx port to tx port of the pair. .. code-block:: c /* spp_forward.c */ for (cnt = 0; cnt < num; cnt++) { rx = &path->ports[cnt].rx; tx = &path->ports[cnt].tx; /* Receive packets */ nb_rx = rte_eth_rx_burst( rx->dpdk_port, 0, bufs, MAX_PKT_BURST); if (unlikely(nb_rx == 0)) continue; #ifdef SPP_RINGLATENCYSTATS_ENABLE if (rx->iface_type == RING) spp_ringlatencystats_calculate_latency( rx->iface_no, bufs, nb_rx); if (tx->iface_type == RING) spp_ringlatencystats_add_time_stamp( tx->iface_no, bufs, nb_rx); #endif /* SPP_RINGLATENCYSTATS_ENABLE */ /* Send packets */ if (tx->dpdk_port >= 0) nb_tx = rte_eth_tx_burst( tx->dpdk_port, 0, bufs, nb_rx); /* Discard remained packets to release mbuf */ if (unlikely(nb_tx < nb_rx)) { for (buf = nb_tx; buf < nb_rx; buf++) rte_pktmbuf_free(bufs[buf]); } } L2 Multicast Support -------------------- SPP_VF also supports multicast for resolving ARP requests. It is implemented as ``handle_l2multicast_packet()`` and called from ``classify_packet()`` for incoming multicast packets. .. code-block:: c /* classify_packet() in classifier_mac.c */ /* L2 multicast(include broadcast) ? */ if (unlikely(is_multicast_ether_addr(ð->d_addr))) { RTE_LOG(DEBUG, SPP_CLASSIFIER_MAC, "multicast mac address.\n"); handle_l2multicast_packet(rx_pkts[i], classifier_info, classified_data); continue; } For distributing multicast packet, it is cloned with ``rte_mbuf_refcnt_update()``. .. code-block:: c /* classifier_mac.c */ /* handle L2 multicast(include broadcast) packet */ static inline void handle_l2multicast_packet(struct rte_mbuf *pkt, struct classifier_mac_info *classifier_info, struct classified_data *classified_data) { int i; if (unlikely(classifier_info->num_active_classified == 0)) { RTE_LOG(ERR, SPP_CLASSIFIER_MAC, "No mac address.(l2 multicast packet)\n"); rte_pktmbuf_free(pkt); return; } rte_mbuf_refcnt_update(pkt, (classifier_info->num_active_classified - 1)); for (i = 0; i < classifier_info->num_active_classified; i++) { push_packet(pkt, classified_data + (long)classifier_info->active_classifieds[i]); } }