1 .. SPDX-License-Identifier: BSD-3-Clause
2 Copyright(c) 2010-2014 Intel Corporation.
4 L3 Forwarding Sample Application
5 ================================
7 The L3 Forwarding application is a simple example of packet processing using
8 DPDK to demonstrate usage of poll and event mode packet I/O mechanism.
9 The application performs L3 forwarding.
14 The application demonstrates the use of the hash, LPM and FIB libraries in DPDK
15 to implement packet forwarding using poll or event mode PMDs for packet I/O.
16 The initialization and run-time paths are very similar to those of the
17 :doc:`l2_forward_real_virtual` and :doc:`l2_forward_event`.
18 The main difference from the L2 Forwarding sample application is that optionally
19 packet can be Rx/Tx from/to eventdev instead of port directly and forwarding
20 decision is made based on information read from the input packet.
22 Eventdev can optionally use S/W or H/W (if supported by platform) scheduler
23 implementation for packet I/O based on run time parameters.
25 The lookup method is hash-based, LPM-based or FIB-based
26 and is selected at run time.
27 When the selected lookup method is hash-based,
28 a hash object is used to emulate the flow classification stage.
29 The hash object is used in correlation with a flow table to map each input packet to its flow at runtime.
31 The hash lookup key is represented by a DiffServ 5-tuple composed of the following fields read from the input packet:
32 Source IP Address, Destination IP Address, Protocol, Source Port and Destination Port.
33 The ID of the output interface for the input packet is read from the identified flow table entry.
34 The set of flows used by the application is statically configured and loaded into the hash at initialization time.
35 When the selected lookup method is LPM or FIB based,
36 an LPM or FIB object is used to emulate the forwarding stage for IPv4 packets.
37 The LPM or FIB object is used as the routing table
38 to identify the next hop for each input packet at runtime.
40 The LPM and FIB lookup keys are represented by the destination IP address field
41 read from the input packet.
42 The ID of the output interface for the input packet is the next hop
43 returned by the LPM or FIB lookup.
44 The set of LPM and FIB rules used by the application is statically configured
45 and loaded into the LPM or FIB object at initialization time.
47 In the sample application, hash-based and FIB-based forwarding supports
49 LPM-based forwarding supports IPv4 only.
50 During the initialization phase route rules for IPv4 and IPv6 are read from rule files.
52 Compiling the Application
53 -------------------------
55 To compile the sample application see :doc:`compiling`.
57 The application is located in the ``l3fwd`` sub-directory.
59 Running the Application
60 -----------------------
62 The application has a number of command line options::
64 ./dpdk-l3fwd [EAL options] -- -p PORTMASK
68 [--lookup LOOKUP_METHOD]
69 --config(port,queue,lcore)[,(port,queue,lcore)]
70 [--eth-dest=X,MM:MM:MM:MM:MM:MM]
71 [--max-pkt-len PKTLEN]
80 [--event-vector [--event-vector-size SIZE] [--event-vector-tmo NS]]
86 * ``-p PORTMASK:`` Hexadecimal bitmask of ports to configure
88 * ``--rule_ipv4=FILE:`` specify the ipv4 rules entries file.
89 Each rule occupies one line.
91 * ``--rule_ipv6=FILE:`` specify the ipv6 rules entries file.
93 * ``-P:`` Optional, sets all ports to promiscuous mode so that packets are accepted regardless of the packet's Ethernet MAC destination address.
94 Without this option, only packets with the Ethernet MAC destination address set to the Ethernet address of the port are accepted.
96 * ``--lookup:`` Optional, select the lookup method.
99 ``lpm`` (Longest Prefix Match),
100 ``fib`` (Forwarding Information Base).
103 * ``--config (port,queue,lcore)[,(port,queue,lcore)]:`` Determines which queues from which ports are mapped to which cores.
105 * ``--eth-dest=X,MM:MM:MM:MM:MM:MM:`` Optional, ethernet destination for port X.
107 * ``--max-pkt-len:`` Optional, maximum packet length in decimal (64-9600).
109 * ``--no-numa:`` Optional, disables numa awareness.
111 * ``--hash-entry-num:`` Optional, specifies the hash entry number in hexadecimal to be setup.
113 * ``--ipv6:`` Optional, set if running ipv6 packets.
115 * ``--parse-ptype:`` Optional, set to use software to analyze packet type. Without this option, hardware will check the packet type.
117 * ``--per-port-pool:`` Optional, set to use independent buffer pools per port. Without this option, single buffer pool is used for all ports.
119 * ``--mode:`` Optional, Packet transfer mode for I/O, poll or eventdev.
121 * ``--eventq-sched:`` Optional, Event queue synchronization method, Ordered, Atomic or Parallel. Only valid if --mode=eventdev.
123 * ``--event-eth-rxqs:`` Optional, Number of ethernet RX queues per device. Only valid if --mode=eventdev.
125 * ``--event-vector:`` Optional, Enable event vectorization. Only valid if --mode=eventdev.
127 * ``--event-vector-size:`` Optional, Max vector size if event vectorization is enabled.
129 * ``--event-vector-tmo:`` Optional, Max timeout to form vector in nanoseconds if event vectorization is enabled.
131 * ``-E:`` Optional, enable exact match,
132 legacy flag, please use ``--lookup=em`` instead.
134 * ``-L:`` Optional, enable longest prefix match,
135 legacy flag, please use ``--lookup=lpm`` instead.
138 For example, consider a dual processor socket platform with 8 physical cores, where cores 0-7 and 16-23 appear on socket 0,
139 while cores 8-15 and 24-31 appear on socket 1.
141 To enable L3 forwarding between two ports, assuming that both ports are in the same socket, using two cores, cores 1 and 2,
142 (which are in the same socket too), use the following command:
144 .. code-block:: console
146 ./<build_dir>/examples/dpdk-l3fwd -l 1,2 -n 4 -- -p 0x3 --config="(0,0,1),(1,0,2)" --rule_ipv4="rule_ipv4.cfg" --rule_ipv6="rule_ipv6.cfg"
150 * The -l option enables cores 1, 2
152 * The -p option enables ports 0 and 1
154 * The --config option enables one queue on each port and maps each (port,queue) pair to a specific core.
155 The following table shows the mapping in this example:
157 +----------+-----------+-----------+-------------------------------------+
158 | **Port** | **Queue** | **lcore** | **Description** |
160 +----------+-----------+-----------+-------------------------------------+
161 | 0 | 0 | 1 | Map queue 0 from port 0 to lcore 1. |
163 +----------+-----------+-----------+-------------------------------------+
164 | 1 | 0 | 2 | Map queue 0 from port 1 to lcore 2. |
166 +----------+-----------+-----------+-------------------------------------+
168 * The -rule_ipv4 option specifies the reading of IPv4 rules sets from the rule_ipv4.cfg file
170 * The -rule_ipv6 option specifies the reading of IPv6 rules sets from the rule_ipv6.cfg file.
172 To use eventdev mode with sync method **ordered** on above mentioned environment,
173 Following is the sample command:
175 .. code-block:: console
177 ./<build_dir>/examples/dpdk-l3fwd -l 0-3 -n 4 -a <event device> -- -p 0x3 --eventq-sched=ordered --rule_ipv4="rule_ipv4.cfg" --rule_ipv6="rule_ipv6.cfg"
181 .. code-block:: console
183 ./<build_dir>/examples/dpdk-l3fwd -l 0-3 -n 4 -a <event device> \
184 -- -p 0x03 --mode=eventdev --eventq-sched=ordered --rule_ipv4="rule_ipv4.cfg" --rule_ipv6="rule_ipv6.cfg"
188 * -a option allows the event device supported by platform.
189 The syntax used to indicate this device may vary based on platform.
191 * The --mode option defines PMD to be used for packet I/O.
193 * The --eventq-sched option enables synchronization menthod of event queue so that packets will be scheduled accordingly.
195 If application uses S/W scheduler, it uses following DPDK services:
198 * Rx adapter service function
199 * Tx adapter service function
201 Application needs service cores to run above mentioned services. Service cores
202 must be provided as EAL parameters along with the --vdev=event_sw0 to enable S/W
203 scheduler. Following is the sample command:
205 .. code-block:: console
207 ./<build_dir>/examples/dpdk-l3fwd -l 0-7 -s 0xf0000 -n 4 --vdev event_sw0 -- -p 0x3 --mode=eventdev --eventq-sched=ordered --rule_ipv4="rule_ipv4.cfg" --rule_ipv6="rule_ipv6.cfg"
209 In case of eventdev mode, *--config* option is not used for ethernet port
210 configuration. Instead each ethernet port will be configured with mentioned
215 * Each Rx queue will be connected to event queue via Rx adapter.
217 * Each Tx queue will be connected via Tx adapter.
219 Refer to the *DPDK Getting Started Guide* for general information on running applications and
220 the Environment Abstraction Layer (EAL) options.
222 .. _l3_fwd_explanation:
227 The following sections provide some explanation of the sample application code. As mentioned in the overview section,
228 the initialization and run-time paths are very similar to those of the :doc:`l2_forward_real_virtual` and :doc:`l2_forward_event`.
229 The following sections describe aspects that are specific to the L3 Forwarding sample application.
231 Parse Rules from File
232 ~~~~~~~~~~~~~~~~~~~~~
234 The application parses the rules from the file and adds them to the appropriate route table by calling the appropriate function.
235 It ignores empty and comment lines, and parses and validates the rules it reads.
236 If errors are detected, the application exits with messages to identify the errors encountered.
238 The format of the route rules differs based on which lookup method is being used.
239 Therefore, the code only decreases the priority number with each rule it parses.
240 Route rules are mandatory.
241 To read data from the specified file successfully, the application assumes the following:
243 * Each rule occupies a single line.
245 * Only the following four rule line types are valid in this application:
247 * Route rule line, which starts with a leading character 'R'
249 * Comment line, which starts with a leading character '#'
251 * Empty line, which consists of a space, form-feed ('\f'), newline ('\n'),
252 carriage return ('\r'), horizontal tab ('\t'), or vertical tab ('\v').
254 Other lines types are considered invalid.
256 * Rules are organized in descending order of priority,
257 which means rules at the head of the file always have a higher priority than those further down in the file.
259 * A typical IPv4 LPM/FIB rule line should have a format as shown below:
261 R<destination_ip>/<ip_mask_length><output_port_number>
263 * A typical IPv4 EM rule line should have a format as shown below:
265 R<destination_ip><source_ip><destination_port><source_port><protocol><output_port_number>
267 IPv4 addresses are specified in CIDR format as specified in RFC 4632.
268 For LPM/FIB they consist of the dot notation for the address and a prefix length separated by '/'.
269 For example, 192.168.0.34/32, where the address is 192.168.0.34 and the prefix length is 32.
270 For EM they consist of just the dot notation for the address and no prefix length.
271 For example, 192.168.0.34, where the Address is 192.168.0.34.
272 EM also includes ports which are specified as a single number which represents a single port.
277 The hash object is created and loaded with the pre-configured entries read from a global array,
278 and then generate the expected 5-tuple as key to keep consistence with those of real flow
279 for the convenience to execute hash performance test on 4M/8M/16M flows.
283 The Hash initialization will setup both ipv4 and ipv6 hash table,
284 and populate the either table depending on the value of variable ipv6.
288 Value of global variable ipv6 can be specified with --ipv6 in the command line.
289 Value of global variable hash_entry_number,
290 which is used to specify the total hash entry number for all used ports in hash performance test,
291 can be specified with --hash-entry-num VALUE in command line, being its default value 4.
295 #if (APP_LOOKUP_METHOD == APP_LOOKUP_EXACT_MATCH)
298 setup_hash(int socketid)
303 /* populate the ipv4 hash */
304 populate_ipv4_flow_into_table(
305 ipv4_l3fwd_em_lookup_struct[socketid]);
307 /* populate the ipv6 hash */
308 populate_ipv6_flow_into_table(
309 ipv6_l3fwd_em_lookup_struct[socketid]);
317 The LPM object is created and loaded with the pre-configured entries read from a global array.
319 .. literalinclude:: ../../../examples/l3fwd/l3fwd_em.c
321 :start-after: Initialize exact match (hash) parameters. 8<
322 :end-before: >8 End of initialization of hash parameters.
327 The FIB object is created and loaded with the pre-configured entries
328 read from a global array.
329 The abridged code snippet below shows the FIB initialization for IPv4,
330 the full setup function including the IPv6 setup can be seen in the app code.
332 .. literalinclude:: ../../../examples/l3fwd/l3fwd_fib.c
334 :start-after: Function to setup fib. 8<
335 :end-before: >8 End of setup fib.
337 Packet Forwarding for Hash-based Lookups
338 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
340 For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward()
341 or simple_ipv4_fwd_4pkts() function for IPv4 packets or the simple_ipv6_fwd_4pkts() function for IPv6 packets.
342 The l3fwd_simple_forward() function provides the basic functionality for both IPv4 and IPv6 packet forwarding
343 for any number of burst packets received,
344 and the packet forwarding decision (that is, the identification of the output interface for the packet)
345 for hash-based lookups is done by the get_ipv4_dst_port() or get_ipv6_dst_port() function.
346 The get_ipv4_dst_port() function is shown below:
348 .. literalinclude:: ../../../examples/l3fwd/l3fwd_em.c
350 :start-after: Performing hash-based lookups. 8<
351 :end-before: >8 End of performing hash-based lookups.
353 The get_ipv6_dst_port() function is similar to the get_ipv4_dst_port() function.
355 The simple_ipv4_fwd_4pkts() and simple_ipv6_fwd_4pkts() function are optimized for continuous 4 valid ipv4 and ipv6 packets,
356 they leverage the multiple buffer optimization to boost the performance of forwarding packets with the exact match on hash table.
357 The key code snippet of simple_ipv4_fwd_4pkts() is shown below:
362 simple_ipv4_fwd_4pkts(struct rte_mbuf* m[4], uint16_t portid, struct lcore_conf *qconf)
366 data[0] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[0], unsigned char *) + sizeof(struct rte_ether_hdr) + offsetof(struct rte_ipv4_hdr, time_to_live)));
367 data[1] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[1], unsigned char *) + sizeof(struct rte_ether_hdr) + offsetof(struct rte_ipv4_hdr, time_to_live)));
368 data[2] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[2], unsigned char *) + sizeof(struct rte_ether_hdr) + offsetof(struct rte_ipv4_hdr, time_to_live)));
369 data[3] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[3], unsigned char *) + sizeof(struct rte_ether_hdr) + offsetof(struct rte_ipv4_hdr, time_to_live)));
371 key[0].xmm = _mm_and_si128(data[0], mask0);
372 key[1].xmm = _mm_and_si128(data[1], mask0);
373 key[2].xmm = _mm_and_si128(data[2], mask0);
374 key[3].xmm = _mm_and_si128(data[3], mask0);
376 const void *key_array[4] = {&key[0], &key[1], &key[2],&key[3]};
378 rte_hash_lookup_bulk(qconf->ipv4_lookup_struct, &key_array[0], 4, ret);
380 dst_port[0] = (ret[0] < 0)? portid:ipv4_l3fwd_out_if[ret[0]];
381 dst_port[1] = (ret[1] < 0)? portid:ipv4_l3fwd_out_if[ret[1]];
382 dst_port[2] = (ret[2] < 0)? portid:ipv4_l3fwd_out_if[ret[2]];
383 dst_port[3] = (ret[3] < 0)? portid:ipv4_l3fwd_out_if[ret[3]];
388 The simple_ipv6_fwd_4pkts() function is similar to the simple_ipv4_fwd_4pkts() function.
390 Known issue: IP packets with extensions or IP packets which are not TCP/UDP cannot work well at this mode.
392 Packet Forwarding for LPM-based Lookups
393 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
395 For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward() function,
396 but the packet forwarding decision (that is, the identification of the output interface for the packet)
397 for LPM-based lookups is done by the get_ipv4_dst_port() function below:
399 .. literalinclude:: ../../../examples/l3fwd/l3fwd_lpm.c
401 :start-after: Performing LPM-based lookups. 8<
402 :end-before: >8 End of performing LPM-based lookups.
404 Packet Forwarding for FIB-based Lookups
405 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
407 The FIB library was designed to process multiple packets at once,
408 it does not have separate functions for single and bulk lookups.
409 ``rte_fib_lookup_bulk`` is used for IPv4 lookups
410 and ``rte_fib6_lookup_bulk`` for IPv6.
411 Various examples of these functions being used
412 can be found in the sample app code.
414 Eventdev Driver Initialization
415 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
416 Eventdev driver initialization is same as L2 forwarding eventdev application.
417 Refer :doc:`l2_forward_event` for more details.