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