-.. 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.
+.. SPDX-License-Identifier: BSD-3-Clause
+ Copyright(c) 2010-2014 Intel Corporation.
+
+.. _l2_fwd_app_real_and_virtual:
L2 Forwarding Sample Application (in Real and Virtualized Environments)
=======================================================================
The destination port is the adjacent port from the enabled portmask, that is,
if the first four ports are enabled (portmask 0xf),
ports 1 and 2 forward into each other, and ports 3 and 4 forward into each other.
-Also, the MAC addresses are affected as follows:
+Also, if MAC addresses updating is enabled, the MAC addresses are affected as follows:
* The source MAC address is replaced by the TX_PORT MAC address
* The destination MAC address is replaced by 02:00:00:00:00:TX_PORT_ID
-This application can be used to benchmark performance using a traffic-generator, as shown in the :numref:`figure_l2_fwd_benchmark_setup`.
-
-The application can also be used in a virtualized environment as shown in :numref:`figure_l2_fwd_virtenv_benchmark_setup`.
-
-The L2 Forwarding application can also be used as a starting point for developing a new application based on the DPDK.
+This application can be used to benchmark performance using a traffic-generator, as shown in the :numref:`figure_l2_fwd_benchmark_setup`,
+or in a virtualized environment as shown in :numref:`figure_l2_fwd_virtenv_benchmark_setup`.
.. _figure_l2_fwd_benchmark_setup:
Performance Benchmark Setup (Basic Environment)
-
.. _figure_l2_fwd_virtenv_benchmark_setup:
.. figure:: img/l2_fwd_virtenv_benchmark_setup.*
Performance Benchmark Setup (Virtualized Environment)
+This application may be used for basic VM to VM communication as shown in :numref:`figure_l2_fwd_vm2vm`,
+when MAC addresses updating is disabled.
+
+.. _figure_l2_fwd_vm2vm:
+
+.. figure:: img/l2_fwd_vm2vm.*
+
+ Virtual Machine to Virtual Machine communication.
+
+The L2 Forwarding application can also be used as a starting point for developing a new application based on the DPDK.
+
+.. _l2_fwd_vf_setup:
Virtual Function Setup Instructions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Compiling the Application
-------------------------
-#. Go to the example directory:
-
- .. code-block:: console
-
- export RTE_SDK=/path/to/rte_sdk
- cd ${RTE_SDK}/examples/l2fwd
+To compile the sample application see :doc:`compiling`.
-#. Set the target (a default target is used if not specified). For example:
-
- .. code-block:: console
-
- export RTE_TARGET=x86_64-native-linuxapp-gcc
-
- *See the DPDK Getting Started Guide* for possible RTE_TARGET values.
-
-#. Build the application:
-
- .. code-block:: console
-
- make
+The application is located in the ``l2fwd`` sub-directory.
Running the Application
-----------------------
.. code-block:: console
- ./build/l2fwd [EAL options] -- -p PORTMASK [-q NQ]
+ ./<build_dir>/examples/dpdk-l2fwd [EAL options] -- -p PORTMASK
+ [-P]
+ [-q NQ]
+ --[no-]mac-updating
+ [--portmap="(port, port)[,(port, port)]"]
where,
* p PORTMASK: A hexadecimal bitmask of the ports to configure
+* P: Optional, set all ports to promiscuous mode
+ so that packets are accepted regardless of the MAC destination address.
+ Without this option, only packets with the MAC destination address
+ set to the Ethernet address of the port are accepted.
+
* q NQ: A number of queues (=ports) per lcore (default is 1)
-To run the application in linuxapp environment with 4 lcores, 16 ports and 8 RX queues per lcore, issue the command:
+* --[no-]mac-updating: Enable or disable MAC addresses updating (enabled by default)
+
+* --portmap="(port,port)[,(port,port)]": Determines forwarding ports mapping.
+
+To run the application in linux environment with 4 lcores, 16 ports and 8 RX queues per lcore and MAC address
+updating enabled, issue the command:
.. code-block:: console
- $ ./build/l2fwd -c f -n 4 -- -q 8 -p ffff
+ $ ./<build_dir>/examples/dpdk-l2fwd -l 0-3 -n 4 -- -q 8 -p ffff
+
+To run the application in linux environment with 4 lcores, 4 ports, 8 RX queues
+per lcore, to forward RX traffic of ports 0 & 1 on ports 2 & 3 respectively and
+vice versa, issue the command:
+
+.. code-block:: console
+
+ $ ./<build_dir>/examples/dpdk-l2fwd -l 0-3 -n 4 -- -q 8 -p f --portmap="(0,2)(1,3)"
Refer to the *DPDK Getting Started Guide* for general information on running applications
and the Environment Abstraction Layer (EAL) options.
The following sections provide some explanation of the code.
+.. _l2_fwd_app_cmd_arguments:
+
Command Line Arguments
~~~~~~~~~~~~~~~~~~~~~~
The L2 Forwarding sample application takes specific parameters,
-in addition to Environment Abstraction Layer (EAL) arguments (see Section 9.3).
+in addition to Environment Abstraction Layer (EAL) arguments.
The preferred way to parse parameters is to use the getopt() function,
since it is part of a well-defined and portable library.
EAL arguments are parsed first, then application-specific arguments.
This is done at the beginning of the main() function:
-.. code-block:: c
-
- /* init EAL */
-
- ret = rte_eal_init(argc, argv);
- if (ret < 0)
- rte_exit(EXIT_FAILURE, "Invalid EAL arguments\n");
-
- argc -= ret;
- argv += ret;
-
- /* parse application arguments (after the EAL ones) */
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: Init EAL. 8<
+ :end-before: >8 End of init EAL.
+ :dedent: 1
- ret = l2fwd_parse_args(argc, argv);
- if (ret < 0)
- rte_exit(EXIT_FAILURE, "Invalid L2FWD arguments\n");
+.. _l2_fwd_app_mbuf_init:
Mbuf Pool Initialization
~~~~~~~~~~~~~~~~~~~~~~~~
The mbuf pool contains a set of mbuf objects that will be used by the driver
and the application to store network packet data:
-.. code-block:: c
-
- /* create the mbuf pool */
-
- l2fwd_pktmbuf_pool = rte_mempool_create("mbuf_pool", NB_MBUF, MBUF_SIZE, 32, sizeof(struct rte_pktmbuf_pool_private),
- rte_pktmbuf_pool_init, NULL, rte_pktmbuf_init, NULL, SOCKET0, 0);
-
- if (l2fwd_pktmbuf_pool == NULL)
- rte_panic("Cannot init mbuf pool\n");
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: Create the mbuf pool. 8<
+ :end-before: >8 End of create the mbuf pool.
+ :dedent: 1
The rte_mempool is a generic structure used to handle pools of objects.
-In this case, it is necessary to create a pool that will be used by the driver,
-which expects to have some reserved space in the mempool structure,
-sizeof(struct rte_pktmbuf_pool_private) bytes.
-The number of allocated pkt mbufs is NB_MBUF, with a size of MBUF_SIZE each.
+In this case, it is necessary to create a pool that will be used by the driver.
+The number of allocated pkt mbufs is NB_MBUF, with a data room size of
+RTE_MBUF_DEFAULT_BUF_SIZE each.
A per-lcore cache of 32 mbufs is kept.
The memory is allocated in NUMA socket 0,
but it is possible to extend this code to allocate one mbuf pool per socket.
-Two callback pointers are also given to the rte_mempool_create() function:
+The rte_pktmbuf_pool_create() function uses the default mbuf pool and mbuf
+initializers, respectively rte_pktmbuf_pool_init() and rte_pktmbuf_init().
+An advanced application may want to use the mempool API to create the
+mbuf pool with more control.
-* The first callback pointer is to rte_pktmbuf_pool_init() and is used
- to initialize the private data of the mempool, which is needed by the driver.
- This function is provided by the mbuf API, but can be copied and extended by the developer.
-
-* The second callback pointer given to rte_mempool_create() is the mbuf initializer.
- The default is used, that is, rte_pktmbuf_init(), which is provided in the rte_mbuf library.
- If a more complex application wants to extend the rte_pktmbuf structure for its own needs,
- a new function derived from rte_pktmbuf_init( ) can be created.
+.. _l2_fwd_app_dvr_init:
Driver Initialization
~~~~~~~~~~~~~~~~~~~~~
To fully understand this code, it is recommended to study the chapters that related to the Poll Mode Driver
in the *DPDK Programmer's Guide* - Rel 1.4 EAR and the *DPDK API Reference*.
-.. code-block:: c
-
- if (rte_eal_pci_probe() < 0)
- rte_exit(EXIT_FAILURE, "Cannot probe PCI\n");
-
- nb_ports = rte_eth_dev_count();
-
- if (nb_ports == 0)
- rte_exit(EXIT_FAILURE, "No Ethernet ports - bye\n");
-
- if (nb_ports > RTE_MAX_ETHPORTS)
- nb_ports = RTE_MAX_ETHPORTS;
-
- /* reset l2fwd_dst_ports */
-
- for (portid = 0; portid < RTE_MAX_ETHPORTS; portid++)
- l2fwd_dst_ports[portid] = 0;
-
- last_port = 0;
-
- /*
- * Each logical core is assigned a dedicated TX queue on each port.
- */
-
- for (portid = 0; portid < nb_ports; portid++) {
- /* skip ports that are not enabled */
-
- if ((l2fwd_enabled_port_mask & (1 << portid)) == 0)
- continue;
-
- if (nb_ports_in_mask % 2) {
- l2fwd_dst_ports[portid] = last_port;
- l2fwd_dst_ports[last_port] = portid;
- }
- else
- last_port = portid;
-
- nb_ports_in_mask++;
-
- rte_eth_dev_info_get((uint8_t) portid, &dev_info);
- }
-
-Observe that:
-
-* rte_igb_pmd_init_all() simultaneously registers the driver as a PCI driver and as an Ethernet* Poll Mode Driver.
-
-* rte_eal_pci_probe() parses the devices on the PCI bus and initializes recognized devices.
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: Initialization of the driver. 8<
+ :end-before: >8 End of initialization of the driver.
+ :dedent: 1
The next step is to configure the RX and TX queues.
For each port, there is only one RX queue (only one lcore is able to poll a given port).
The number of TX queues depends on the number of available lcores.
The rte_eth_dev_configure() function is used to configure the number of queues for a port:
-.. code-block:: c
-
- ret = rte_eth_dev_configure((uint8_t)portid, 1, 1, &port_conf);
- if (ret < 0)
- rte_exit(EXIT_FAILURE, "Cannot configure device: "
- "err=%d, port=%u\n",
- ret, portid);
-
-The global configuration is stored in a static structure:
-
-.. code-block:: c
-
- static const struct rte_eth_conf port_conf = {
- .rxmode = {
- .split_hdr_size = 0,
- .header_split = 0, /**< Header Split disabled */
- .hw_ip_checksum = 0, /**< IP checksum offload disabled */
- .hw_vlan_filter = 0, /**< VLAN filtering disabled */
- .jumbo_frame = 0, /**< Jumbo Frame Support disabled */
- .hw_strip_crc= 0, /**< CRC stripped by hardware */
- },
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: Configure the number of queues for a port.
+ :end-before: >8 End of configuration of the number of queues for a port.
+ :dedent: 2
- .txmode = {
- .mq_mode = ETH_DCB_NONE
- },
- };
+.. _l2_fwd_app_rx_init:
RX Queue Initialization
~~~~~~~~~~~~~~~~~~~~~~~
If there are 16 ports on the target (and if the portmask argument is -p ffff ),
the application will need four lcores to poll all the ports.
-.. code-block:: c
-
- ret = rte_eth_rx_queue_setup((uint8_t) portid, 0, nb_rxd, SOCKET0, &rx_conf, l2fwd_pktmbuf_pool);
- if (ret < 0)
-
- rte_exit(EXIT_FAILURE, "rte_eth_rx_queue_setup: "
- "err=%d, port=%u\n",
- ret, portid);
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: RX queue setup. 8<
+ :end-before: >8 End of RX queue setup.
+ :dedent: 2
The list of queues that must be polled for a given lcore is stored in a private structure called struct lcore_queue_conf.
-.. code-block:: c
-
- struct lcore_queue_conf {
- unsigned n_rx_port;
- unsigned rx_port_list[MAX_RX_QUEUE_PER_LCORE];
- struct mbuf_table tx_mbufs[L2FWD_MAX_PORTS];
- } rte_cache_aligned;
-
- struct lcore_queue_conf lcore_queue_conf[RTE_MAX_LCORE];
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: List of queues to be polled for a given lcore. 8<
+ :end-before: >8 End of list of queues to be polled for a given lcore.
The values n_rx_port and rx_port_list[] are used in the main packet processing loop
-(see Section 9.4.6 "Receive, Process and Transmit Packets" later in this chapter).
-
-The global configuration for the RX queues is stored in a static structure:
-
-.. code-block:: c
+(see :ref:`l2_fwd_app_rx_tx_packets`).
- static const struct rte_eth_rxconf rx_conf = {
- .rx_thresh = {
- .pthresh = RX_PTHRESH,
- .hthresh = RX_HTHRESH,
- .wthresh = RX_WTHRESH,
- },
- };
+.. _l2_fwd_app_tx_init:
TX Queue Initialization
~~~~~~~~~~~~~~~~~~~~~~~
Each lcore should be able to transmit on any port. For every port, a single TX queue is initialized.
-.. code-block:: c
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: Init one TX queue on each port. 8<
+ :end-before: >8 End of init one TX queue on each port.
+ :dedent: 2
- /* init one TX queue on each port */
-
- fflush(stdout);
-
- ret = rte_eth_tx_queue_setup((uint8_t) portid, 0, nb_txd, rte_eth_dev_socket_id(portid), &tx_conf);
- if (ret < 0)
- rte_exit(EXIT_FAILURE, "rte_eth_tx_queue_setup:err=%d, port=%u\n", ret, (unsigned) portid);
-
-The global configuration for TX queues is stored in a static structure:
-
-.. code-block:: c
-
- static const struct rte_eth_txconf tx_conf = {
- .tx_thresh = {
- .pthresh = TX_PTHRESH,
- .hthresh = TX_HTHRESH,
- .wthresh = TX_WTHRESH,
- },
- .tx_free_thresh = RTE_TEST_TX_DESC_DEFAULT + 1, /* disable feature */
- };
+.. _l2_fwd_app_rx_tx_packets:
Receive, Process and Transmit Packets
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In the l2fwd_main_loop() function, the main task is to read ingress packets from the RX queues.
This is done using the following code:
-.. code-block:: c
-
- /*
- * Read packet from RX queues
- */
-
- for (i = 0; i < qconf->n_rx_port; i++) {
- portid = qconf->rx_port_list[i];
- nb_rx = rte_eth_rx_burst((uint8_t) portid, 0, pkts_burst, MAX_PKT_BURST);
-
- for (j = 0; j < nb_rx; j++) {
- m = pkts_burst[j];
- rte_prefetch0[rte_pktmbuf_mtod(m, void *)); l2fwd_simple_forward(m, portid);
- }
- }
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: Read packet from RX queues. 8<
+ :end-before: >8 End of read packet from RX queues.
+ :dedent: 2
Packets are read in a burst of size MAX_PKT_BURST.
The rte_eth_rx_burst() function writes the mbuf pointers in a local table and returns the number of available mbufs in the table.
Then, each mbuf in the table is processed by the l2fwd_simple_forward() function.
-The processing is very simple: process the TX port from the RX port, then replace the source and destination MAC addresses.
+The processing is very simple: process the TX port from the RX port, then replace the source and destination MAC addresses if MAC
+addresses updating is enabled.
.. note::
a destination port is assigned that is either the next or previous enabled port from the portmask.
Naturally, the number of ports in the portmask must be even, otherwise, the application exits.
-.. code-block:: c
-
- static void
- l2fwd_simple_forward(struct rte_mbuf *m, unsigned portid)
- {
- struct ether_hdr *eth;
- void *tmp;
- unsigned dst_port;
-
- dst_port = l2fwd_dst_ports[portid];
-
- eth = rte_pktmbuf_mtod(m, struct ether_hdr *);
-
- /* 02:00:00:00:00:xx */
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: Simple forward. 8<
+ :end-before: >8 End of simple forward.
- tmp = ð->d_addr.addr_bytes[0];
-
- *((uint64_t *)tmp) = 0x000000000002 + ((uint64_t) dst_port << 40);
-
- /* src addr */
-
- ether_addr_copy(&l2fwd_ports_eth_addr[dst_port], ð->s_addr);
-
- l2fwd_send_packet(m, (uint8_t) dst_port);
- }
Then, the packet is sent using the l2fwd_send_packet (m, dst_port) function.
For this test application, the processing is exactly the same for all packets arriving on the same RX port.
The l2fwd_send_packet() function stores the packet in a per-lcore and per-txport table.
If the table is full, the whole packets table is transmitted using the l2fwd_send_burst() function:
-.. code-block:: c
-
- /* Send the packet on an output interface */
-
- static int
- l2fwd_send_packet(struct rte_mbuf *m, uint8_t port)
- {
- unsigned lcore_id, len;
- struct lcore_queue_conf \*qconf;
-
- lcore_id = rte_lcore_id();
- qconf = &lcore_queue_conf[lcore_id];
- len = qconf->tx_mbufs[port].len;
- qconf->tx_mbufs[port].m_table[len] = m;
- len++;
-
- /* enough pkts to be sent */
-
- if (unlikely(len == MAX_PKT_BURST)) {
- l2fwd_send_burst(qconf, MAX_PKT_BURST, port);
- len = 0;
- }
-
- qconf->tx_mbufs[port].len = len; return 0;
- }
+.. literalinclude:: ../../../examples/l2fwd-crypto/main.c
+ :language: c
+ :start-after: Enqueue packets for TX and prepare them to be sent. 8<
+ :end-before: >8 End of Enqueuing packets for TX.
To ensure that no packets remain in the tables, each lcore does a draining of TX queue in its main loop.
This technique introduces some latency when there are not many packets to send,
however it improves performance:
-.. code-block:: c
-
- cur_tsc = rte_rdtsc();
-
- /*
- * TX burst queue drain
- */
-
- diff_tsc = cur_tsc - prev_tsc;
-
- if (unlikely(diff_tsc > drain_tsc)) {
- for (portid = 0; portid < RTE_MAX_ETHPORTS; portid++) {
- if (qconf->tx_mbufs[portid].len == 0)
- continue;
-
- l2fwd_send_burst(&lcore_queue_conf[lcore_id], qconf->tx_mbufs[portid].len, (uint8_t) portid);
-
- qconf->tx_mbufs[portid].len = 0;
- }
-
- /* if timer is enabled */
-
- if (timer_period > 0) {
- /* advance the timer */
-
- timer_tsc += diff_tsc;
-
- /* if timer has reached its timeout */
-
- if (unlikely(timer_tsc >= (uint64_t) timer_period)) {
- /* do this only on master core */
-
- if (lcore_id == rte_get_master_lcore()) {
- print_stats();
-
- /* reset the timer */
- timer_tsc = 0;
- }
- }
- }
-
- prev_tsc = cur_tsc;
- }
+.. literalinclude:: ../../../examples/l2fwd/main.c
+ :language: c
+ :start-after: Drains TX queue in its main loop. 8<
+ :end-before: >8 End of draining TX queue.
+ :dedent: 2