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numam-dpdk/doc/guides/sample_app_ug/flow_classify.rst
Thomas Monjalon a9dbe18022 fix ethdev port id validation 
Some DPDK applications wrongly assume these requirements:
    - no hotplug, i.e. ports are never detached
    - all allocated ports are available to the application

Such application assume a valid port index is in the range [0..count[.

There are three consequences when using such wrong design:
    - new ports having an index higher than the port count won't be valid
    - old ports being detached (RTE_ETH_DEV_UNUSED) can be valid

Such mistake will be less common with growing hotplug awareness.
All applications and examples inside this repository - except testpmd -
must be fixed to use the function rte_eth_dev_is_valid_port.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
2018-04-18 00:37:05 +02:00

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.. SPDX-License-Identifier: BSD-3-Clause
Copyright(c) 2017 Intel Corporation.
Flow Classify Sample Application
================================
The Flow Classify sample application is based on the simple *skeleton* example
of a forwarding application.
It is intended as a demonstration of the basic components of a DPDK forwarding
application which uses the Flow Classify library API's.
Please refer to the
:doc:`../prog_guide/flow_classify_lib`
for more information.
Compiling the Application
-------------------------
To compile the sample application see :doc:`compiling`.
The application is located in the ``flow_classify`` sub-directory.
Running the Application
-----------------------
To run the example in a ``linuxapp`` environment:
.. code-block:: console
cd ~/dpdk/examples/flow_classify
./build/flow_classify -c 4 -n 4 -- --rule_ipv4="../ipv4_rules_file.txt"
Please refer to the *DPDK Getting Started Guide*, section
:doc:`../linux_gsg/build_sample_apps`
for general information on running applications and the Environment Abstraction
Layer (EAL) options.
Sample ipv4_rules_file.txt
--------------------------
.. code-block:: console
#file format:
#src_ip/masklen dst_ip/masklen src_port : mask dst_port : mask proto/mask priority
#
2.2.2.3/24 2.2.2.7/24 32 : 0xffff 33 : 0xffff 17/0xff 0
9.9.9.3/24 9.9.9.7/24 32 : 0xffff 33 : 0xffff 17/0xff 1
9.9.9.3/24 9.9.9.7/24 32 : 0xffff 33 : 0xffff 6/0xff 2
9.9.8.3/24 9.9.8.7/24 32 : 0xffff 33 : 0xffff 6/0xff 3
6.7.8.9/24 2.3.4.5/24 32 : 0x0000 33 : 0x0000 132/0xff 4
Explanation
-----------
The following sections provide an explanation of the main components of the
code.
All DPDK library functions used in the sample code are prefixed with ``rte_``
and are explained in detail in the *DPDK API Documentation*.
ACL field definitions for the IPv4 5 tuple rule
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The following field definitions are used when creating the ACL table during
initialisation of the ``Flow Classify`` application..
.. code-block:: c
enum {
PROTO_FIELD_IPV4,
SRC_FIELD_IPV4,
DST_FIELD_IPV4,
SRCP_FIELD_IPV4,
DSTP_FIELD_IPV4,
NUM_FIELDS_IPV4
};
enum {
PROTO_INPUT_IPV4,
SRC_INPUT_IPV4,
DST_INPUT_IPV4,
SRCP_DESTP_INPUT_IPV4
};
static struct rte_acl_field_def ipv4_defs[NUM_FIELDS_IPV4] = {
/* first input field - always one byte long. */
{
.type = RTE_ACL_FIELD_TYPE_BITMASK,
.size = sizeof(uint8_t),
.field_index = PROTO_FIELD_IPV4,
.input_index = PROTO_INPUT_IPV4,
.offset = sizeof(struct ether_hdr) +
offsetof(struct ipv4_hdr, next_proto_id),
},
/* next input field (IPv4 source address) - 4 consecutive bytes. */
{
/* rte_flow uses a bit mask for IPv4 addresses */
.type = RTE_ACL_FIELD_TYPE_BITMASK,
.size = sizeof(uint32_t),
.field_index = SRC_FIELD_IPV4,
.input_index = SRC_INPUT_IPV4,
.offset = sizeof(struct ether_hdr) +
offsetof(struct ipv4_hdr, src_addr),
},
/* next input field (IPv4 destination address) - 4 consecutive bytes. */
{
/* rte_flow uses a bit mask for IPv4 addresses */
.type = RTE_ACL_FIELD_TYPE_BITMASK,
.size = sizeof(uint32_t),
.field_index = DST_FIELD_IPV4,
.input_index = DST_INPUT_IPV4,
.offset = sizeof(struct ether_hdr) +
offsetof(struct ipv4_hdr, dst_addr),
},
/*
* Next 2 fields (src & dst ports) form 4 consecutive bytes.
* They share the same input index.
*/
{
/* rte_flow uses a bit mask for protocol ports */
.type = RTE_ACL_FIELD_TYPE_BITMASK,
.size = sizeof(uint16_t),
.field_index = SRCP_FIELD_IPV4,
.input_index = SRCP_DESTP_INPUT_IPV4,
.offset = sizeof(struct ether_hdr) +
sizeof(struct ipv4_hdr) +
offsetof(struct tcp_hdr, src_port),
},
{
/* rte_flow uses a bit mask for protocol ports */
.type = RTE_ACL_FIELD_TYPE_BITMASK,
.size = sizeof(uint16_t),
.field_index = DSTP_FIELD_IPV4,
.input_index = SRCP_DESTP_INPUT_IPV4,
.offset = sizeof(struct ether_hdr) +
sizeof(struct ipv4_hdr) +
offsetof(struct tcp_hdr, dst_port),
},
};
The Main Function
~~~~~~~~~~~~~~~~~
The ``main()`` function performs the initialization and calls the execution
threads for each lcore.
The first task is to initialize the Environment Abstraction Layer (EAL).
The ``argc`` and ``argv`` arguments are provided to the ``rte_eal_init()``
function. The value returned is the number of parsed arguments:
.. code-block:: c
int ret = rte_eal_init(argc, argv);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
It then parses the flow_classify application arguments
.. code-block:: c
ret = parse_args(argc, argv);
if (ret < 0)
rte_exit(EXIT_FAILURE, "Invalid flow_classify parameters\n");
The ``main()`` function also allocates a mempool to hold the mbufs
(Message Buffers) used by the application:
.. code-block:: c
mbuf_pool = rte_mempool_create("MBUF_POOL",
NUM_MBUFS * nb_ports,
MBUF_SIZE,
MBUF_CACHE_SIZE,
sizeof(struct rte_pktmbuf_pool_private),
rte_pktmbuf_pool_init, NULL,
rte_pktmbuf_init, NULL,
rte_socket_id(),
0);
mbufs are the packet buffer structure used by DPDK. They are explained in
detail in the "Mbuf Library" section of the *DPDK Programmer's Guide*.
The ``main()`` function also initializes all the ports using the user defined
``port_init()`` function which is explained in the next section:
.. code-block:: c
RTE_ETH_FOREACH_DEV(portid) {
if (port_init(portid, mbuf_pool) != 0) {
rte_exit(EXIT_FAILURE,
"Cannot init port %" PRIu8 "\n", portid);
}
}
The ``main()`` function creates the ``flow classifier object`` and adds an ``ACL
table`` to the flow classifier.
.. code-block:: c
struct flow_classifier {
struct rte_flow_classifier *cls;
};
struct flow_classifier_acl {
struct flow_classifier cls;
} __rte_cache_aligned;
/* Memory allocation */
size = RTE_CACHE_LINE_ROUNDUP(sizeof(struct flow_classifier_acl));
cls_app = rte_zmalloc(NULL, size, RTE_CACHE_LINE_SIZE);
if (cls_app == NULL)
rte_exit(EXIT_FAILURE, "Cannot allocate classifier memory\n");
cls_params.name = "flow_classifier";
cls_params.socket_id = socket_id;
cls_app->cls = rte_flow_classifier_create(&cls_params);
if (cls_app->cls == NULL) {
rte_free(cls_app);
rte_exit(EXIT_FAILURE, "Cannot create classifier\n");
}
/* initialise ACL table params */
table_acl_params.name = "table_acl_ipv4_5tuple";
table_acl_params.n_rule_fields = RTE_DIM(ipv4_defs);
table_acl_params.n_rules = FLOW_CLASSIFY_MAX_RULE_NUM;
memcpy(table_acl_params.field_format, ipv4_defs, sizeof(ipv4_defs));
/* initialise table create params */
cls_table_params.ops = &rte_table_acl_ops,
cls_table_params.arg_create = &table_acl_params,
cls_table_params.type = RTE_FLOW_CLASSIFY_TABLE_ACL_IP4_5TUPLE;
ret = rte_flow_classify_table_create(cls_app->cls, &cls_table_params);
if (ret) {
rte_flow_classifier_free(cls_app->cls);
rte_free(cls);
rte_exit(EXIT_FAILURE, "Failed to create classifier table\n");
}
It then reads the ipv4_rules_file.txt file and initialises the parameters for
the ``rte_flow_classify_table_entry_add`` API.
This API adds a rule to the ACL table.
.. code-block:: c
if (add_rules(parm_config.rule_ipv4_name)) {
rte_flow_classifier_free(cls_app->cls);
rte_free(cls_app);
rte_exit(EXIT_FAILURE, "Failed to add rules\n");
}
Once the initialization is complete, the application is ready to launch a
function on an lcore. In this example ``lcore_main()`` is called on a single
lcore.
.. code-block:: c
lcore_main(cls_app);
The ``lcore_main()`` function is explained below.
The Port Initialization Function
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The main functional part of the port initialization used in the Basic
Forwarding application is shown below:
.. code-block:: c
static inline int
port_init(uint8_t port, struct rte_mempool *mbuf_pool)
{
struct rte_eth_conf port_conf = port_conf_default;
const uint16_t rx_rings = 1, tx_rings = 1;
struct ether_addr addr;
int retval;
uint16_t q;
/* Configure the Ethernet device. */
retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
if (retval != 0)
return retval;
/* Allocate and set up 1 RX queue per Ethernet port. */
for (q = 0; q < rx_rings; q++) {
retval = rte_eth_rx_queue_setup(port, q, RX_RING_SIZE,
rte_eth_dev_socket_id(port), NULL, mbuf_pool);
if (retval < 0)
return retval;
}
/* Allocate and set up 1 TX queue per Ethernet port. */
for (q = 0; q < tx_rings; q++) {
retval = rte_eth_tx_queue_setup(port, q, TX_RING_SIZE,
rte_eth_dev_socket_id(port), NULL);
if (retval < 0)
return retval;
}
/* Start the Ethernet port. */
retval = rte_eth_dev_start(port);
if (retval < 0)
return retval;
/* Display the port MAC address. */
rte_eth_macaddr_get(port, &addr);
printf("Port %u MAC: %02" PRIx8 " %02" PRIx8 " %02" PRIx8
" %02" PRIx8 " %02" PRIx8 " %02" PRIx8 "\n",
port,
addr.addr_bytes[0], addr.addr_bytes[1],
addr.addr_bytes[2], addr.addr_bytes[3],
addr.addr_bytes[4], addr.addr_bytes[5]);
/* Enable RX in promiscuous mode for the Ethernet device. */
rte_eth_promiscuous_enable(port);
return 0;
}
The Ethernet ports are configured with default settings using the
``rte_eth_dev_configure()`` function and the ``port_conf_default`` struct.
.. code-block:: c
static const struct rte_eth_conf port_conf_default = {
.rxmode = { .max_rx_pkt_len = ETHER_MAX_LEN }
};
For this example the ports are set up with 1 RX and 1 TX queue using the
``rte_eth_rx_queue_setup()`` and ``rte_eth_tx_queue_setup()`` functions.
The Ethernet port is then started:
.. code-block:: c
retval = rte_eth_dev_start(port);
Finally the RX port is set in promiscuous mode:
.. code-block:: c
rte_eth_promiscuous_enable(port);
The Add Rules function
~~~~~~~~~~~~~~~~~~~~~~
The ``add_rules`` function reads the ``ipv4_rules_file.txt`` file and calls the
``add_classify_rule`` function which calls the
``rte_flow_classify_table_entry_add`` API.
.. code-block:: c
static int
add_rules(const char *rule_path)
{
FILE *fh;
char buff[LINE_MAX];
unsigned int i = 0;
unsigned int total_num = 0;
struct rte_eth_ntuple_filter ntuple_filter;
fh = fopen(rule_path, "rb");
if (fh == NULL)
rte_exit(EXIT_FAILURE, "%s: Open %s failed\n", __func__,
rule_path);
fseek(fh, 0, SEEK_SET);
i = 0;
while (fgets(buff, LINE_MAX, fh) != NULL) {
i++;
if (is_bypass_line(buff))
continue;
if (total_num >= FLOW_CLASSIFY_MAX_RULE_NUM - 1) {
printf("\nINFO: classify rule capacity %d reached\n",
total_num);
break;
}
if (parse_ipv4_5tuple_rule(buff, &ntuple_filter) != 0)
rte_exit(EXIT_FAILURE,
"%s Line %u: parse rules error\n",
rule_path, i);
if (add_classify_rule(&ntuple_filter) != 0)
rte_exit(EXIT_FAILURE, "add rule error\n");
total_num++;
}
fclose(fh);
return 0;
}
The Lcore Main function
~~~~~~~~~~~~~~~~~~~~~~~
As we saw above the ``main()`` function calls an application function on the
available lcores.
The ``lcore_main`` function calls the ``rte_flow_classifier_query`` API.
For the Basic Forwarding application the ``lcore_main`` function looks like the
following:
.. code-block:: c
/* flow classify data */
static int num_classify_rules;
static struct rte_flow_classify_rule *rules[MAX_NUM_CLASSIFY];
static struct rte_flow_classify_ipv4_5tuple_stats ntuple_stats;
static struct rte_flow_classify_stats classify_stats = {
.stats = (void *)&ntuple_stats
};
static __attribute__((noreturn)) void
lcore_main(cls_app)
{
uint16_t port;
/*
* Check that the port is on the same NUMA node as the polling thread
* for best performance.
*/
RTE_ETH_FOREACH_DEV(port)
if (rte_eth_dev_socket_id(port) > 0 &&
rte_eth_dev_socket_id(port) != (int)rte_socket_id()) {
printf("\n\n");
printf("WARNING: port %u is on remote NUMA node\n",
port);
printf("to polling thread.\n");
printf("Performance will not be optimal.\n");
printf("\nCore %u forwarding packets. \n",
rte_lcore_id());
printf("[Ctrl+C to quit]\n
}
/* Run until the application is quit or killed. */
for (;;) {
/*
* Receive packets on a port and forward them on the paired
* port. The mapping is 0 -> 1, 1 -> 0, 2 -> 3, 3 -> 2, etc.
*/
RTE_ETH_FOREACH_DEV(port) {
/* Get burst of RX packets, from first port of pair. */
struct rte_mbuf *bufs[BURST_SIZE];
const uint16_t nb_rx = rte_eth_rx_burst(port, 0,
bufs, BURST_SIZE);
if (unlikely(nb_rx == 0))
continue;
for (i = 0; i < MAX_NUM_CLASSIFY; i++) {
if (rules[i]) {
ret = rte_flow_classifier_query(
cls_app->cls,
bufs, nb_rx, rules[i],
&classify_stats);
if (ret)
printf(
"rule [%d] query failed ret [%d]\n\n",
i, ret);
else {
printf(
"rule[%d] count=%"PRIu64"\n",
i, ntuple_stats.counter1);
printf("proto = %d\n",
ntuple_stats.ipv4_5tuple.proto);
}
}
}
/* Send burst of TX packets, to second port of pair. */
const uint16_t nb_tx = rte_eth_tx_burst(port ^ 1, 0,
bufs, nb_rx);
/* Free any unsent packets. */
if (unlikely(nb_tx < nb_rx)) {
uint16_t buf;
for (buf = nb_tx; buf < nb_rx; buf++)
rte_pktmbuf_free(bufs[buf]);
}
}
}
}
The main work of the application is done within the loop:
.. code-block:: c
for (;;) {
RTE_ETH_FOREACH_DEV(port) {
/* Get burst of RX packets, from first port of pair. */
struct rte_mbuf *bufs[BURST_SIZE];
const uint16_t nb_rx = rte_eth_rx_burst(port, 0,
bufs, BURST_SIZE);
if (unlikely(nb_rx == 0))
continue;
/* Send burst of TX packets, to second port of pair. */
const uint16_t nb_tx = rte_eth_tx_burst(port ^ 1, 0,
bufs, nb_rx);
/* Free any unsent packets. */
if (unlikely(nb_tx < nb_rx)) {
uint16_t buf;
for (buf = nb_tx; buf < nb_rx; buf++)
rte_pktmbuf_free(bufs[buf]);
}
}
}
Packets are received in bursts on the RX ports and transmitted in bursts on
the TX ports. The ports are grouped in pairs with a simple mapping scheme
using the an XOR on the port number::
0 -> 1
1 -> 0
2 -> 3
3 -> 2
etc.
The ``rte_eth_tx_burst()`` function frees the memory buffers of packets that
are transmitted. If packets fail to transmit, ``(nb_tx < nb_rx)``, then they
must be freed explicitly using ``rte_pktmbuf_free()``.
The forwarding loop can be interrupted and the application closed using
``Ctrl-C``.
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