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diff --git a/doc/guides/sample_app_ug/l3_forward.rst b/doc/guides/sample_app_ug/l3_forward.rst new file mode 100644 index 00000000..3e070d0b --- /dev/null +++ b/doc/guides/sample_app_ug/l3_forward.rst @@ -0,0 +1,356 @@ +.. 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. + +L3 Forwarding Sample Application +================================ + +The L3 Forwarding application is a simple example of packet processing using the DPDK. +The application performs L3 forwarding. + +Overview +-------- + +The application demonstrates the use of the hash and LPM libraries in the DPDK to implement packet forwarding. +The initialization and run-time paths are very similar to those of the :doc:`l2_forward_real_virtual`. +The main difference from the L2 Forwarding sample application is that the forwarding decision +is made based on information read from the input packet. + +The lookup method is either hash-based or LPM-based and is selected at compile time. When the selected lookup method is hash-based, +a hash object is used to emulate the flow classification stage. +The hash object is used in correlation with a flow table to map each input packet to its flow at runtime. + +The hash lookup key is represented by a DiffServ 5-tuple composed of the following fields read from the input packet: +Source IP Address, Destination IP Address, Protocol, Source Port and Destination Port. +The ID of the output interface for the input packet is read from the identified flow table entry. +The set of flows used by the application is statically configured and loaded into the hash at initialization time. +When the selected lookup method is LPM based, an LPM object is used to emulate the forwarding stage for IPv4 packets. +The LPM object is used as the routing table to identify the next hop for each input packet at runtime. + +The LPM lookup key is represented by the Destination IP Address field read from the input packet. +The ID of the output interface for the input packet is the next hop returned by the LPM lookup. +The set of LPM rules used by the application is statically configured and loaded into the LPM object at initialization time. + +In the sample application, hash-based forwarding supports IPv4 and IPv6. LPM-based forwarding supports IPv4 only. + +Compiling the Application +------------------------- + +To compile the application: + +#. Go to the sample application directory: + + .. code-block:: console + + export RTE_SDK=/path/to/rte_sdk + cd ${RTE_SDK}/examples/l3fwd + +#. 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 + +Running the Application +----------------------- + +The application has a number of command line options: + +.. code-block:: console + + ./build/l3fwd [EAL options] -- -p PORTMASK [-P] --config(port,queue,lcore)[,(port,queue,lcore)] [--enable-jumbo [--max-pkt-len PKTLEN]] [--no-numa][--hash-entry-num][--ipv6] [--parse-ptype] + +where, + +* -p PORTMASK: Hexadecimal bitmask of ports to configure + +* -P: optional, sets all ports to promiscuous mode so that packets are accepted regardless of the packet's Ethernet MAC destination address. + Without this option, only packets with the Ethernet MAC destination address set to the Ethernet address of the port are accepted. + +* --config (port,queue,lcore)[,(port,queue,lcore)]: determines which queues from which ports are mapped to which cores + +* --enable-jumbo: optional, enables jumbo frames + +* --max-pkt-len: optional, maximum packet length in decimal (64-9600) + +* --no-numa: optional, disables numa awareness + +* --hash-entry-num: optional, specifies the hash entry number in hexadecimal to be setup + +* --ipv6: optional, set it if running ipv6 packets + +* --parse-ptype: optional, set it if use software way to analyze packet type + +For example, consider a dual processor socket platform where cores 0-7 and 16-23 appear on socket 0, while cores 8-15 and 24-31 appear on socket 1. +Let's say that the programmer wants to use memory from both NUMA nodes, the platform has only two ports, one connected to each NUMA node, +and the programmer wants to use two cores from each processor socket to do the packet processing. + +To enable L3 forwarding between two ports, using two cores, cores 1 and 2, from each processor, +while also taking advantage of local memory access by optimizing around NUMA, the programmer must enable two queues from each port, +pin to the appropriate cores and allocate memory from the appropriate NUMA node. This is achieved using the following command: + +.. code-block:: console + + ./build/l3fwd -c 606 -n 4 -- -p 0x3 --config="(0,0,1),(0,1,2),(1,0,9),(1,1,10)" + +In this command: + +* The -c option enables cores 0, 1, 2, 3 + +* The -p option enables ports 0 and 1 + +* The --config option enables two queues on each port and maps each (port,queue) pair to a specific core. + Logic to enable multiple RX queues using RSS and to allocate memory from the correct NUMA nodes + is included in the application and is done transparently. + The following table shows the mapping in this example: + ++----------+-----------+-----------+-------------------------------------+ +| **Port** | **Queue** | **lcore** | **Description** | +| | | | | ++----------+-----------+-----------+-------------------------------------+ +| 0 | 0 | 0 | Map queue 0 from port 0 to lcore 0. | +| | | | | ++----------+-----------+-----------+-------------------------------------+ +| 0 | 1 | 2 | Map queue 1 from port 0 to lcore 2. | +| | | | | ++----------+-----------+-----------+-------------------------------------+ +| 1 | 0 | 1 | Map queue 0 from port 1 to lcore 1. | +| | | | | ++----------+-----------+-----------+-------------------------------------+ +| 1 | 1 | 3 | Map queue 1 from port 1 to lcore 3. | +| | | | | ++----------+-----------+-----------+-------------------------------------+ + +Refer to the *DPDK Getting Started Guide* for general information on running applications and +the Environment Abstraction Layer (EAL) options. + +.. _l3_fwd_explanation: + +Explanation +----------- + +The following sections provide some explanation of the sample application code. As mentioned in the overview section, +the initialization and run-time paths are very similar to those of the :doc:`l2_forward_real_virtual`. +The following sections describe aspects that are specific to the L3 Forwarding sample application. + +Hash Initialization +~~~~~~~~~~~~~~~~~~~ + +The hash object is created and loaded with the pre-configured entries read from a global array, +and then generate the expected 5-tuple as key to keep consistence with those of real flow +for the convenience to execute hash performance test on 4M/8M/16M flows. + +.. note:: + + The Hash initialization will setup both ipv4 and ipv6 hash table, + and populate the either table depending on the value of variable ipv6. + To support the hash performance test with up to 8M single direction flows/16M bi-direction flows, + populate_ipv4_many_flow_into_table() function will populate the hash table with specified hash table entry number(default 4M). + +.. note:: + + Value of global variable ipv6 can be specified with --ipv6 in the command line. + Value of global variable hash_entry_number, + which is used to specify the total hash entry number for all used ports in hash performance test, + can be specified with --hash-entry-num VALUE in command line, being its default value 4. + +.. code-block:: c + + #if (APP_LOOKUP_METHOD == APP_LOOKUP_EXACT_MATCH) + + static void + setup_hash(int socketid) + { + // ... + + if (hash_entry_number != HASH_ENTRY_NUMBER_DEFAULT) { + if (ipv6 == 0) { + /* populate the ipv4 hash */ + populate_ipv4_many_flow_into_table(ipv4_l3fwd_lookup_struct[socketid], hash_entry_number); + } else { + /* populate the ipv6 hash */ + populate_ipv6_many_flow_into_table( ipv6_l3fwd_lookup_struct[socketid], hash_entry_number); + } + } else + if (ipv6 == 0) { + /* populate the ipv4 hash */ + populate_ipv4_few_flow_into_table(ipv4_l3fwd_lookup_struct[socketid]); + } else { + /* populate the ipv6 hash */ + populate_ipv6_few_flow_into_table(ipv6_l3fwd_lookup_struct[socketid]); + } + } + } + #endif + +LPM Initialization +~~~~~~~~~~~~~~~~~~ + +The LPM object is created and loaded with the pre-configured entries read from a global array. + +.. code-block:: c + + #if (APP_LOOKUP_METHOD == APP_LOOKUP_LPM) + + static void + setup_lpm(int socketid) + { + unsigned i; + int ret; + char s[64]; + + /* create the LPM table */ + + snprintf(s, sizeof(s), "IPV4_L3FWD_LPM_%d", socketid); + + ipv4_l3fwd_lookup_struct[socketid] = rte_lpm_create(s, socketid, IPV4_L3FWD_LPM_MAX_RULES, 0); + + if (ipv4_l3fwd_lookup_struct[socketid] == NULL) + rte_exit(EXIT_FAILURE, "Unable to create the l3fwd LPM table" + " on socket %d\n", socketid); + + /* populate the LPM table */ + + for (i = 0; i < IPV4_L3FWD_NUM_ROUTES; i++) { + /* skip unused ports */ + + if ((1 << ipv4_l3fwd_route_array[i].if_out & enabled_port_mask) == 0) + continue; + + ret = rte_lpm_add(ipv4_l3fwd_lookup_struct[socketid], ipv4_l3fwd_route_array[i].ip, + ipv4_l3fwd_route_array[i].depth, ipv4_l3fwd_route_array[i].if_out); + + if (ret < 0) { + rte_exit(EXIT_FAILURE, "Unable to add entry %u to the " + "l3fwd LPM table on socket %d\n", i, socketid); + } + + printf("LPM: Adding route 0x%08x / %d (%d)\n", + (unsigned)ipv4_l3fwd_route_array[i].ip, ipv4_l3fwd_route_array[i].depth, ipv4_l3fwd_route_array[i].if_out); + } + } + #endif + +Packet Forwarding for Hash-based Lookups +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward() +or simple_ipv4_fwd_4pkts() function for IPv4 packets or the simple_ipv6_fwd_4pkts() function for IPv6 packets. +The l3fwd_simple_forward() function provides the basic functionality for both IPv4 and IPv6 packet forwarding +for any number of burst packets received, +and the packet forwarding decision (that is, the identification of the output interface for the packet) +for hash-based lookups is done by the get_ipv4_dst_port() or get_ipv6_dst_port() function. +The get_ipv4_dst_port() function is shown below: + +.. code-block:: c + + static inline uint8_t + get_ipv4_dst_port(void *ipv4_hdr, uint8_t portid, lookup_struct_t *ipv4_l3fwd_lookup_struct) + { + int ret = 0; + union ipv4_5tuple_host key; + + ipv4_hdr = (uint8_t \*)ipv4_hdr + offsetof(struct ipv4_hdr, time_to_live); + + m128i data = _mm_loadu_si128(( m128i*)(ipv4_hdr)); + + /* Get 5 tuple: dst port, src port, dst IP address, src IP address and protocol */ + + key.xmm = _mm_and_si128(data, mask0); + + /* Find destination port */ + + ret = rte_hash_lookup(ipv4_l3fwd_lookup_struct, (const void *)&key); + + return (uint8_t)((ret < 0)? portid : ipv4_l3fwd_out_if[ret]); + } + +The get_ipv6_dst_port() function is similar to the get_ipv4_dst_port() function. + +The simple_ipv4_fwd_4pkts() and simple_ipv6_fwd_4pkts() function are optimized for continuous 4 valid ipv4 and ipv6 packets, +they leverage the multiple buffer optimization to boost the performance of forwarding packets with the exact match on hash table. +The key code snippet of simple_ipv4_fwd_4pkts() is shown below: + +.. code-block:: c + + static inline void + simple_ipv4_fwd_4pkts(struct rte_mbuf* m[4], uint8_t portid, struct lcore_conf *qconf) + { + // ... + + data[0] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[0], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); + data[1] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[1], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); + data[2] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[2], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); + data[3] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[3], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); + + key[0].xmm = _mm_and_si128(data[0], mask0); + key[1].xmm = _mm_and_si128(data[1], mask0); + key[2].xmm = _mm_and_si128(data[2], mask0); + key[3].xmm = _mm_and_si128(data[3], mask0); + + const void *key_array[4] = {&key[0], &key[1], &key[2],&key[3]}; + + rte_hash_lookup_multi(qconf->ipv4_lookup_struct, &key_array[0], 4, ret); + + dst_port[0] = (ret[0] < 0)? portid:ipv4_l3fwd_out_if[ret[0]]; + dst_port[1] = (ret[1] < 0)? portid:ipv4_l3fwd_out_if[ret[1]]; + dst_port[2] = (ret[2] < 0)? portid:ipv4_l3fwd_out_if[ret[2]]; + dst_port[3] = (ret[3] < 0)? portid:ipv4_l3fwd_out_if[ret[3]]; + + // ... + } + +The simple_ipv6_fwd_4pkts() function is similar to the simple_ipv4_fwd_4pkts() function. + +Known issue: IP packets with extensions or IP packets which are not TCP/UDP cannot work well at this mode. + +Packet Forwarding for LPM-based Lookups +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward() function, +but the packet forwarding decision (that is, the identification of the output interface for the packet) +for LPM-based lookups is done by the get_ipv4_dst_port() function below: + +.. code-block:: c + + static inline uint8_t + get_ipv4_dst_port(struct ipv4_hdr *ipv4_hdr, uint8_t portid, lookup_struct_t *ipv4_l3fwd_lookup_struct) + { + uint8_t next_hop; + + return (uint8_t) ((rte_lpm_lookup(ipv4_l3fwd_lookup_struct, rte_be_to_cpu_32(ipv4_hdr->dst_addr), &next_hop) == 0)? next_hop : portid); + } |