1.. BSD LICENSE 2 Copyright(c) 2010-2014 Intel Corporation. All rights reserved. 3 All rights reserved. 4 5 Redistribution and use in source and binary forms, with or without 6 modification, are permitted provided that the following conditions 7 are met: 8 9 * Redistributions of source code must retain the above copyright 10 notice, this list of conditions and the following disclaimer. 11 * Redistributions in binary form must reproduce the above copyright 12 notice, this list of conditions and the following disclaimer in 13 the documentation and/or other materials provided with the 14 distribution. 15 * Neither the name of Intel Corporation nor the names of its 16 contributors may be used to endorse or promote products derived 17 from this software without specific prior written permission. 18 19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31L3 Forwarding Sample Application 32================================ 33 34The L3 Forwarding application is a simple example of packet processing using the DPDK. 35The application performs L3 forwarding. 36 37Overview 38-------- 39 40The application demonstrates the use of the hash and LPM libraries in the DPDK to implement packet forwarding. 41The initialization and run-time paths are very similar to those of the :doc:`l2_forward_real_virtual`. 42The main difference from the L2 Forwarding sample application is that the forwarding decision 43is made based on information read from the input packet. 44 45The lookup method is either hash-based or LPM-based and is selected at compile time. When the selected lookup method is hash-based, 46a hash object is used to emulate the flow classification stage. 47The hash object is used in correlation with a flow table to map each input packet to its flow at runtime. 48 49The hash lookup key is represented by a DiffServ 5-tuple composed of the following fields read from the input packet: 50Source IP Address, Destination IP Address, Protocol, Source Port and Destination Port. 51The ID of the output interface for the input packet is read from the identified flow table entry. 52The set of flows used by the application is statically configured and loaded into the hash at initialization time. 53When the selected lookup method is LPM based, an LPM object is used to emulate the forwarding stage for IPv4 packets. 54The LPM object is used as the routing table to identify the next hop for each input packet at runtime. 55 56The LPM lookup key is represented by the Destination IP Address field read from the input packet. 57The ID of the output interface for the input packet is the next hop returned by the LPM lookup. 58The set of LPM rules used by the application is statically configured and loaded into the LPM object at initialization time. 59 60In the sample application, hash-based forwarding supports IPv4 and IPv6. LPM-based forwarding supports IPv4 only. 61 62Compiling the Application 63------------------------- 64 65To compile the application: 66 67#. Go to the sample application directory: 68 69 .. code-block:: console 70 71 export RTE_SDK=/path/to/rte_sdk 72 cd ${RTE_SDK}/examples/l3fwd 73 74#. Set the target (a default target is used if not specified). For example: 75 76 .. code-block:: console 77 78 export RTE_TARGET=x86_64-native-linuxapp-gcc 79 80 See the *DPDK Getting Started Guide* for possible RTE_TARGET values. 81 82#. Build the application: 83 84 .. code-block:: console 85 86 make 87 88Running the Application 89----------------------- 90 91The application has a number of command line options: 92 93.. code-block:: console 94 95 ./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] 96 97where, 98 99* -p PORTMASK: Hexadecimal bitmask of ports to configure 100 101* -P: optional, sets all ports to promiscuous mode so that packets are accepted regardless of the packet's Ethernet MAC destination address. 102 Without this option, only packets with the Ethernet MAC destination address set to the Ethernet address of the port are accepted. 103 104* --config (port,queue,lcore)[,(port,queue,lcore)]: determines which queues from which ports are mapped to which cores 105 106* --enable-jumbo: optional, enables jumbo frames 107 108* --max-pkt-len: optional, maximum packet length in decimal (64-9600) 109 110* --no-numa: optional, disables numa awareness 111 112* --hash-entry-num: optional, specifies the hash entry number in hexadecimal to be setup 113 114* --ipv6: optional, set it if running ipv6 packets 115 116* --parse-ptype: optional, set it if use software way to analyze packet type 117 118For 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. 119Let'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, 120and the programmer wants to use two cores from each processor socket to do the packet processing. 121 122To enable L3 forwarding between two ports, using two cores, cores 1 and 2, from each processor, 123while also taking advantage of local memory access by optimizing around NUMA, the programmer must enable two queues from each port, 124pin to the appropriate cores and allocate memory from the appropriate NUMA node. This is achieved using the following command: 125 126.. code-block:: console 127 128 ./build/l3fwd -c 606 -n 4 -- -p 0x3 --config="(0,0,1),(0,1,2),(1,0,9),(1,1,10)" 129 130In this command: 131 132* The -c option enables cores 0, 1, 2, 3 133 134* The -p option enables ports 0 and 1 135 136* The --config option enables two queues on each port and maps each (port,queue) pair to a specific core. 137 Logic to enable multiple RX queues using RSS and to allocate memory from the correct NUMA nodes 138 is included in the application and is done transparently. 139 The following table shows the mapping in this example: 140 141+----------+-----------+-----------+-------------------------------------+ 142| **Port** | **Queue** | **lcore** | **Description** | 143| | | | | 144+----------+-----------+-----------+-------------------------------------+ 145| 0 | 0 | 0 | Map queue 0 from port 0 to lcore 0. | 146| | | | | 147+----------+-----------+-----------+-------------------------------------+ 148| 0 | 1 | 2 | Map queue 1 from port 0 to lcore 2. | 149| | | | | 150+----------+-----------+-----------+-------------------------------------+ 151| 1 | 0 | 1 | Map queue 0 from port 1 to lcore 1. | 152| | | | | 153+----------+-----------+-----------+-------------------------------------+ 154| 1 | 1 | 3 | Map queue 1 from port 1 to lcore 3. | 155| | | | | 156+----------+-----------+-----------+-------------------------------------+ 157 158Refer to the *DPDK Getting Started Guide* for general information on running applications and 159the Environment Abstraction Layer (EAL) options. 160 161.. _l3_fwd_explanation: 162 163Explanation 164----------- 165 166The following sections provide some explanation of the sample application code. As mentioned in the overview section, 167the initialization and run-time paths are very similar to those of the :doc:`l2_forward_real_virtual`. 168The following sections describe aspects that are specific to the L3 Forwarding sample application. 169 170Hash Initialization 171~~~~~~~~~~~~~~~~~~~ 172 173The hash object is created and loaded with the pre-configured entries read from a global array, 174and then generate the expected 5-tuple as key to keep consistence with those of real flow 175for the convenience to execute hash performance test on 4M/8M/16M flows. 176 177.. note:: 178 179 The Hash initialization will setup both ipv4 and ipv6 hash table, 180 and populate the either table depending on the value of variable ipv6. 181 To support the hash performance test with up to 8M single direction flows/16M bi-direction flows, 182 populate_ipv4_many_flow_into_table() function will populate the hash table with specified hash table entry number(default 4M). 183 184.. note:: 185 186 Value of global variable ipv6 can be specified with --ipv6 in the command line. 187 Value of global variable hash_entry_number, 188 which is used to specify the total hash entry number for all used ports in hash performance test, 189 can be specified with --hash-entry-num VALUE in command line, being its default value 4. 190 191.. code-block:: c 192 193 #if (APP_LOOKUP_METHOD == APP_LOOKUP_EXACT_MATCH) 194 195 static void 196 setup_hash(int socketid) 197 { 198 // ... 199 200 if (hash_entry_number != HASH_ENTRY_NUMBER_DEFAULT) { 201 if (ipv6 == 0) { 202 /* populate the ipv4 hash */ 203 populate_ipv4_many_flow_into_table(ipv4_l3fwd_lookup_struct[socketid], hash_entry_number); 204 } else { 205 /* populate the ipv6 hash */ 206 populate_ipv6_many_flow_into_table( ipv6_l3fwd_lookup_struct[socketid], hash_entry_number); 207 } 208 } else 209 if (ipv6 == 0) { 210 /* populate the ipv4 hash */ 211 populate_ipv4_few_flow_into_table(ipv4_l3fwd_lookup_struct[socketid]); 212 } else { 213 /* populate the ipv6 hash */ 214 populate_ipv6_few_flow_into_table(ipv6_l3fwd_lookup_struct[socketid]); 215 } 216 } 217 } 218 #endif 219 220LPM Initialization 221~~~~~~~~~~~~~~~~~~ 222 223The LPM object is created and loaded with the pre-configured entries read from a global array. 224 225.. code-block:: c 226 227 #if (APP_LOOKUP_METHOD == APP_LOOKUP_LPM) 228 229 static void 230 setup_lpm(int socketid) 231 { 232 unsigned i; 233 int ret; 234 char s[64]; 235 236 /* create the LPM table */ 237 238 snprintf(s, sizeof(s), "IPV4_L3FWD_LPM_%d", socketid); 239 240 ipv4_l3fwd_lookup_struct[socketid] = rte_lpm_create(s, socketid, IPV4_L3FWD_LPM_MAX_RULES, 0); 241 242 if (ipv4_l3fwd_lookup_struct[socketid] == NULL) 243 rte_exit(EXIT_FAILURE, "Unable to create the l3fwd LPM table" 244 " on socket %d\n", socketid); 245 246 /* populate the LPM table */ 247 248 for (i = 0; i < IPV4_L3FWD_NUM_ROUTES; i++) { 249 /* skip unused ports */ 250 251 if ((1 << ipv4_l3fwd_route_array[i].if_out & enabled_port_mask) == 0) 252 continue; 253 254 ret = rte_lpm_add(ipv4_l3fwd_lookup_struct[socketid], ipv4_l3fwd_route_array[i].ip, 255 ipv4_l3fwd_route_array[i].depth, ipv4_l3fwd_route_array[i].if_out); 256 257 if (ret < 0) { 258 rte_exit(EXIT_FAILURE, "Unable to add entry %u to the " 259 "l3fwd LPM table on socket %d\n", i, socketid); 260 } 261 262 printf("LPM: Adding route 0x%08x / %d (%d)\n", 263 (unsigned)ipv4_l3fwd_route_array[i].ip, ipv4_l3fwd_route_array[i].depth, ipv4_l3fwd_route_array[i].if_out); 264 } 265 } 266 #endif 267 268Packet Forwarding for Hash-based Lookups 269~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 270 271For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward() 272or simple_ipv4_fwd_4pkts() function for IPv4 packets or the simple_ipv6_fwd_4pkts() function for IPv6 packets. 273The l3fwd_simple_forward() function provides the basic functionality for both IPv4 and IPv6 packet forwarding 274for any number of burst packets received, 275and the packet forwarding decision (that is, the identification of the output interface for the packet) 276for hash-based lookups is done by the get_ipv4_dst_port() or get_ipv6_dst_port() function. 277The get_ipv4_dst_port() function is shown below: 278 279.. code-block:: c 280 281 static inline uint8_t 282 get_ipv4_dst_port(void *ipv4_hdr, uint8_t portid, lookup_struct_t *ipv4_l3fwd_lookup_struct) 283 { 284 int ret = 0; 285 union ipv4_5tuple_host key; 286 287 ipv4_hdr = (uint8_t \*)ipv4_hdr + offsetof(struct ipv4_hdr, time_to_live); 288 289 m128i data = _mm_loadu_si128(( m128i*)(ipv4_hdr)); 290 291 /* Get 5 tuple: dst port, src port, dst IP address, src IP address and protocol */ 292 293 key.xmm = _mm_and_si128(data, mask0); 294 295 /* Find destination port */ 296 297 ret = rte_hash_lookup(ipv4_l3fwd_lookup_struct, (const void *)&key); 298 299 return (uint8_t)((ret < 0)? portid : ipv4_l3fwd_out_if[ret]); 300 } 301 302The get_ipv6_dst_port() function is similar to the get_ipv4_dst_port() function. 303 304The simple_ipv4_fwd_4pkts() and simple_ipv6_fwd_4pkts() function are optimized for continuous 4 valid ipv4 and ipv6 packets, 305they leverage the multiple buffer optimization to boost the performance of forwarding packets with the exact match on hash table. 306The key code snippet of simple_ipv4_fwd_4pkts() is shown below: 307 308.. code-block:: c 309 310 static inline void 311 simple_ipv4_fwd_4pkts(struct rte_mbuf* m[4], uint8_t portid, struct lcore_conf *qconf) 312 { 313 // ... 314 315 data[0] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[0], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); 316 data[1] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[1], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); 317 data[2] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[2], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); 318 data[3] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[3], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); 319 320 key[0].xmm = _mm_and_si128(data[0], mask0); 321 key[1].xmm = _mm_and_si128(data[1], mask0); 322 key[2].xmm = _mm_and_si128(data[2], mask0); 323 key[3].xmm = _mm_and_si128(data[3], mask0); 324 325 const void *key_array[4] = {&key[0], &key[1], &key[2],&key[3]}; 326 327 rte_hash_lookup_multi(qconf->ipv4_lookup_struct, &key_array[0], 4, ret); 328 329 dst_port[0] = (ret[0] < 0)? portid:ipv4_l3fwd_out_if[ret[0]]; 330 dst_port[1] = (ret[1] < 0)? portid:ipv4_l3fwd_out_if[ret[1]]; 331 dst_port[2] = (ret[2] < 0)? portid:ipv4_l3fwd_out_if[ret[2]]; 332 dst_port[3] = (ret[3] < 0)? portid:ipv4_l3fwd_out_if[ret[3]]; 333 334 // ... 335 } 336 337The simple_ipv6_fwd_4pkts() function is similar to the simple_ipv4_fwd_4pkts() function. 338 339Known issue: IP packets with extensions or IP packets which are not TCP/UDP cannot work well at this mode. 340 341Packet Forwarding for LPM-based Lookups 342~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 343 344For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward() function, 345but the packet forwarding decision (that is, the identification of the output interface for the packet) 346for LPM-based lookups is done by the get_ipv4_dst_port() function below: 347 348.. code-block:: c 349 350 static inline uint8_t 351 get_ipv4_dst_port(struct ipv4_hdr *ipv4_hdr, uint8_t portid, lookup_struct_t *ipv4_l3fwd_lookup_struct) 352 { 353 uint8_t next_hop; 354 355 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); 356 } 357