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 run 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 sample application see :doc:`compiling`. 66 67The application is located in the ``l3fwd`` sub-directory. 68 69Running the Application 70----------------------- 71 72The application has a number of command line options:: 73 74 ./l3fwd [EAL options] -- -p PORTMASK 75 [-P] 76 [-E] 77 [-L] 78 --config(port,queue,lcore)[,(port,queue,lcore)] 79 [--eth-dest=X,MM:MM:MM:MM:MM:MM] 80 [--enable-jumbo [--max-pkt-len PKTLEN]] 81 [--no-numa] 82 [--hash-entry-num] 83 [--ipv6] 84 [--parse-ptype] 85 86Where, 87 88* ``-p PORTMASK:`` Hexadecimal bitmask of ports to configure 89 90* ``-P:`` Optional, sets all ports to promiscuous mode so that packets are accepted regardless of the packet's Ethernet MAC destination address. 91 Without this option, only packets with the Ethernet MAC destination address set to the Ethernet address of the port are accepted. 92 93* ``-E:`` Optional, enable exact match. 94 95* ``-L:`` Optional, enable longest prefix match. 96 97* ``--config (port,queue,lcore)[,(port,queue,lcore)]:`` Determines which queues from which ports are mapped to which cores. 98 99* ``--eth-dest=X,MM:MM:MM:MM:MM:MM:`` Optional, ethernet destination for port X. 100 101* ``--enable-jumbo:`` Optional, enables jumbo frames. 102 103* ``--max-pkt-len:`` Optional, under the premise of enabling jumbo, maximum packet length in decimal (64-9600). 104 105* ``--no-numa:`` Optional, disables numa awareness. 106 107* ``--hash-entry-num:`` Optional, specifies the hash entry number in hexadecimal to be setup. 108 109* ``--ipv6:`` Optional, set if running ipv6 packets. 110 111* ``--parse-ptype:`` Optional, set to use software to analyze packet type. Without this option, hardware will check the packet type. 112 113For example, consider a dual processor socket platform with 8 physical cores, where cores 0-7 and 16-23 appear on socket 0, 114while cores 8-15 and 24-31 appear on socket 1. 115 116To enable L3 forwarding between two ports, assuming that both ports are in the same socket, using two cores, cores 1 and 2, 117(which are in the same socket too), use the following command: 118 119.. code-block:: console 120 121 ./build/l3fwd -l 1,2 -n 4 -- -p 0x3 --config="(0,0,1),(1,0,2)" 122 123In this command: 124 125* The -l option enables cores 1, 2 126 127* The -p option enables ports 0 and 1 128 129* The --config option enables one queue on each port and maps each (port,queue) pair to a specific core. 130 The following table shows the mapping in this example: 131 132+----------+-----------+-----------+-------------------------------------+ 133| **Port** | **Queue** | **lcore** | **Description** | 134| | | | | 135+----------+-----------+-----------+-------------------------------------+ 136| 0 | 0 | 1 | Map queue 0 from port 0 to lcore 1. | 137| | | | | 138+----------+-----------+-----------+-------------------------------------+ 139| 1 | 0 | 2 | Map queue 0 from port 1 to lcore 2. | 140| | | | | 141+----------+-----------+-----------+-------------------------------------+ 142 143Refer to the *DPDK Getting Started Guide* for general information on running applications and 144the Environment Abstraction Layer (EAL) options. 145 146.. _l3_fwd_explanation: 147 148Explanation 149----------- 150 151The following sections provide some explanation of the sample application code. As mentioned in the overview section, 152the initialization and run-time paths are very similar to those of the :doc:`l2_forward_real_virtual`. 153The following sections describe aspects that are specific to the L3 Forwarding sample application. 154 155Hash Initialization 156~~~~~~~~~~~~~~~~~~~ 157 158The hash object is created and loaded with the pre-configured entries read from a global array, 159and then generate the expected 5-tuple as key to keep consistence with those of real flow 160for the convenience to execute hash performance test on 4M/8M/16M flows. 161 162.. note:: 163 164 The Hash initialization will setup both ipv4 and ipv6 hash table, 165 and populate the either table depending on the value of variable ipv6. 166 To support the hash performance test with up to 8M single direction flows/16M bi-direction flows, 167 populate_ipv4_many_flow_into_table() function will populate the hash table with specified hash table entry number(default 4M). 168 169.. note:: 170 171 Value of global variable ipv6 can be specified with --ipv6 in the command line. 172 Value of global variable hash_entry_number, 173 which is used to specify the total hash entry number for all used ports in hash performance test, 174 can be specified with --hash-entry-num VALUE in command line, being its default value 4. 175 176.. code-block:: c 177 178 #if (APP_LOOKUP_METHOD == APP_LOOKUP_EXACT_MATCH) 179 180 static void 181 setup_hash(int socketid) 182 { 183 // ... 184 185 if (hash_entry_number != HASH_ENTRY_NUMBER_DEFAULT) { 186 if (ipv6 == 0) { 187 /* populate the ipv4 hash */ 188 populate_ipv4_many_flow_into_table(ipv4_l3fwd_lookup_struct[socketid], hash_entry_number); 189 } else { 190 /* populate the ipv6 hash */ 191 populate_ipv6_many_flow_into_table( ipv6_l3fwd_lookup_struct[socketid], hash_entry_number); 192 } 193 } else 194 if (ipv6 == 0) { 195 /* populate the ipv4 hash */ 196 populate_ipv4_few_flow_into_table(ipv4_l3fwd_lookup_struct[socketid]); 197 } else { 198 /* populate the ipv6 hash */ 199 populate_ipv6_few_flow_into_table(ipv6_l3fwd_lookup_struct[socketid]); 200 } 201 } 202 } 203 #endif 204 205LPM Initialization 206~~~~~~~~~~~~~~~~~~ 207 208The LPM object is created and loaded with the pre-configured entries read from a global array. 209 210.. code-block:: c 211 212 #if (APP_LOOKUP_METHOD == APP_LOOKUP_LPM) 213 214 static void 215 setup_lpm(int socketid) 216 { 217 unsigned i; 218 int ret; 219 char s[64]; 220 221 /* create the LPM table */ 222 223 snprintf(s, sizeof(s), "IPV4_L3FWD_LPM_%d", socketid); 224 225 ipv4_l3fwd_lookup_struct[socketid] = rte_lpm_create(s, socketid, IPV4_L3FWD_LPM_MAX_RULES, 0); 226 227 if (ipv4_l3fwd_lookup_struct[socketid] == NULL) 228 rte_exit(EXIT_FAILURE, "Unable to create the l3fwd LPM table" 229 " on socket %d\n", socketid); 230 231 /* populate the LPM table */ 232 233 for (i = 0; i < IPV4_L3FWD_NUM_ROUTES; i++) { 234 /* skip unused ports */ 235 236 if ((1 << ipv4_l3fwd_route_array[i].if_out & enabled_port_mask) == 0) 237 continue; 238 239 ret = rte_lpm_add(ipv4_l3fwd_lookup_struct[socketid], ipv4_l3fwd_route_array[i].ip, 240 ipv4_l3fwd_route_array[i].depth, ipv4_l3fwd_route_array[i].if_out); 241 242 if (ret < 0) { 243 rte_exit(EXIT_FAILURE, "Unable to add entry %u to the " 244 "l3fwd LPM table on socket %d\n", i, socketid); 245 } 246 247 printf("LPM: Adding route 0x%08x / %d (%d)\n", 248 (unsigned)ipv4_l3fwd_route_array[i].ip, ipv4_l3fwd_route_array[i].depth, ipv4_l3fwd_route_array[i].if_out); 249 } 250 } 251 #endif 252 253Packet Forwarding for Hash-based Lookups 254~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 255 256For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward() 257or simple_ipv4_fwd_4pkts() function for IPv4 packets or the simple_ipv6_fwd_4pkts() function for IPv6 packets. 258The l3fwd_simple_forward() function provides the basic functionality for both IPv4 and IPv6 packet forwarding 259for any number of burst packets received, 260and the packet forwarding decision (that is, the identification of the output interface for the packet) 261for hash-based lookups is done by the get_ipv4_dst_port() or get_ipv6_dst_port() function. 262The get_ipv4_dst_port() function is shown below: 263 264.. code-block:: c 265 266 static inline uint8_t 267 get_ipv4_dst_port(void *ipv4_hdr, uint16_t portid, lookup_struct_t *ipv4_l3fwd_lookup_struct) 268 { 269 int ret = 0; 270 union ipv4_5tuple_host key; 271 272 ipv4_hdr = (uint8_t *)ipv4_hdr + offsetof(struct ipv4_hdr, time_to_live); 273 274 m128i data = _mm_loadu_si128(( m128i*)(ipv4_hdr)); 275 276 /* Get 5 tuple: dst port, src port, dst IP address, src IP address and protocol */ 277 278 key.xmm = _mm_and_si128(data, mask0); 279 280 /* Find destination port */ 281 282 ret = rte_hash_lookup(ipv4_l3fwd_lookup_struct, (const void *)&key); 283 284 return (uint8_t)((ret < 0)? portid : ipv4_l3fwd_out_if[ret]); 285 } 286 287The get_ipv6_dst_port() function is similar to the get_ipv4_dst_port() function. 288 289The simple_ipv4_fwd_4pkts() and simple_ipv6_fwd_4pkts() function are optimized for continuous 4 valid ipv4 and ipv6 packets, 290they leverage the multiple buffer optimization to boost the performance of forwarding packets with the exact match on hash table. 291The key code snippet of simple_ipv4_fwd_4pkts() is shown below: 292 293.. code-block:: c 294 295 static inline void 296 simple_ipv4_fwd_4pkts(struct rte_mbuf* m[4], uint16_t portid, struct lcore_conf *qconf) 297 { 298 // ... 299 300 data[0] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[0], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); 301 data[1] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[1], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); 302 data[2] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[2], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); 303 data[3] = _mm_loadu_si128(( m128i*)(rte_pktmbuf_mtod(m[3], unsigned char *) + sizeof(struct ether_hdr) + offsetof(struct ipv4_hdr, time_to_live))); 304 305 key[0].xmm = _mm_and_si128(data[0], mask0); 306 key[1].xmm = _mm_and_si128(data[1], mask0); 307 key[2].xmm = _mm_and_si128(data[2], mask0); 308 key[3].xmm = _mm_and_si128(data[3], mask0); 309 310 const void *key_array[4] = {&key[0], &key[1], &key[2],&key[3]}; 311 312 rte_hash_lookup_bulk(qconf->ipv4_lookup_struct, &key_array[0], 4, ret); 313 314 dst_port[0] = (ret[0] < 0)? portid:ipv4_l3fwd_out_if[ret[0]]; 315 dst_port[1] = (ret[1] < 0)? portid:ipv4_l3fwd_out_if[ret[1]]; 316 dst_port[2] = (ret[2] < 0)? portid:ipv4_l3fwd_out_if[ret[2]]; 317 dst_port[3] = (ret[3] < 0)? portid:ipv4_l3fwd_out_if[ret[3]]; 318 319 // ... 320 } 321 322The simple_ipv6_fwd_4pkts() function is similar to the simple_ipv4_fwd_4pkts() function. 323 324Known issue: IP packets with extensions or IP packets which are not TCP/UDP cannot work well at this mode. 325 326Packet Forwarding for LPM-based Lookups 327~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 328 329For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward() function, 330but the packet forwarding decision (that is, the identification of the output interface for the packet) 331for LPM-based lookups is done by the get_ipv4_dst_port() function below: 332 333.. code-block:: c 334 335 static inline uint16_t 336 get_ipv4_dst_port(struct ipv4_hdr *ipv4_hdr, uint16_t portid, lookup_struct_t *ipv4_l3fwd_lookup_struct) 337 { 338 uint8_t next_hop; 339 340 return ((rte_lpm_lookup(ipv4_l3fwd_lookup_struct, rte_be_to_cpu_32(ipv4_hdr->dst_addr), &next_hop) == 0)? next_hop : portid); 341 } 342