1 /*- 2 * Copyright (c) 2010-2011 Juniper Networks, Inc. 3 * All rights reserved. 4 * 5 * This software was developed by Robert N. M. Watson under contract 6 * to Juniper Networks, Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 31 #include "opt_inet6.h" 32 #include "opt_inet.h" 33 #include "opt_rss.h" 34 35 #include <sys/param.h> 36 #include <sys/mbuf.h> 37 #include <sys/socket.h> 38 #include <sys/priv.h> 39 #include <sys/kernel.h> 40 #include <sys/smp.h> 41 #include <sys/sysctl.h> 42 #include <sys/sbuf.h> 43 44 #include <net/if.h> 45 #include <net/if_var.h> 46 #include <net/netisr.h> 47 #include <net/rss_config.h> 48 #include <net/toeplitz.h> 49 50 /*- 51 * Operating system parts of receiver-side scaling (RSS), which allows 52 * network cards to direct flows to particular receive queues based on hashes 53 * of header tuples. This implementation aligns RSS buckets with connection 54 * groups at the TCP/IP layer, so each bucket is associated with exactly one 55 * group. As a result, the group lookup structures (and lock) should have an 56 * effective affinity with exactly one CPU. 57 * 58 * Network device drivers needing to configure RSS will query this framework 59 * for parameters, such as the current RSS key, hashing policies, number of 60 * bits, and indirection table mapping hashes to buckets and CPUs. They may 61 * provide their own supplementary information, such as queue<->CPU bindings. 62 * It is the responsibility of the network device driver to inject packets 63 * into the stack on as close to the right CPU as possible, if playing by RSS 64 * rules. 65 * 66 * TODO: 67 * 68 * - Synchronization for rss_key and other future-configurable parameters. 69 * - Event handler drivers can register to pick up RSS configuration changes. 70 * - Should we allow rss_basecpu to be configured? 71 * - Randomize key on boot. 72 * - IPv6 support. 73 * - Statistics on how often there's a misalignment between hardware 74 * placement and pcbgroup expectations. 75 */ 76 77 #if !defined(INET) && !defined(INET6) 78 #define _net_inet _net 79 #define _net_inet_rss _net_rss 80 #endif 81 SYSCTL_DECL(_net_inet); 82 SYSCTL_NODE(_net_inet, OID_AUTO, rss, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 83 "Receive-side steering"); 84 85 /* 86 * Toeplitz is the only required hash function in the RSS spec, so use it by 87 * default. 88 */ 89 static u_int rss_hashalgo = RSS_HASH_TOEPLITZ; 90 SYSCTL_INT(_net_inet_rss, OID_AUTO, hashalgo, CTLFLAG_RDTUN, &rss_hashalgo, 0, 91 "RSS hash algorithm"); 92 93 #ifdef RSS 94 FEATURE(rss, "Receiver-side scaling"); 95 /* 96 * Size of the indirection table; at most 128 entries per the RSS spec. We 97 * size it to at least 2 times the number of CPUs by default to allow useful 98 * rebalancing. If not set explicitly with a loader tunable, we tune based 99 * on the number of CPUs present. 100 * 101 * XXXRW: buckets might be better to use for the tunable than bits. 102 */ 103 static u_int rss_bits; 104 SYSCTL_INT(_net_inet_rss, OID_AUTO, bits, CTLFLAG_RDTUN, &rss_bits, 0, 105 "RSS bits"); 106 107 static u_int rss_mask; 108 SYSCTL_INT(_net_inet_rss, OID_AUTO, mask, CTLFLAG_RD, &rss_mask, 0, 109 "RSS mask"); 110 111 static const u_int rss_maxbits = RSS_MAXBITS; 112 SYSCTL_INT(_net_inet_rss, OID_AUTO, maxbits, CTLFLAG_RD, 113 __DECONST(int *, &rss_maxbits), 0, "RSS maximum bits"); 114 115 /* 116 * RSS's own count of the number of CPUs it could be using for processing. 117 * Bounded to 64 by RSS constants. 118 */ 119 static u_int rss_ncpus; 120 SYSCTL_INT(_net_inet_rss, OID_AUTO, ncpus, CTLFLAG_RD, &rss_ncpus, 0, 121 "Number of CPUs available to RSS"); 122 123 #define RSS_MAXCPUS (1 << (RSS_MAXBITS - 1)) 124 static const u_int rss_maxcpus = RSS_MAXCPUS; 125 SYSCTL_INT(_net_inet_rss, OID_AUTO, maxcpus, CTLFLAG_RD, 126 __DECONST(int *, &rss_maxcpus), 0, "RSS maximum CPUs that can be used"); 127 128 /* 129 * Variable exists just for reporting rss_bits in a user-friendly way. 130 */ 131 static u_int rss_buckets; 132 SYSCTL_INT(_net_inet_rss, OID_AUTO, buckets, CTLFLAG_RD, &rss_buckets, 0, 133 "RSS buckets"); 134 135 /* 136 * Base CPU number; devices will add this to all CPU numbers returned by the 137 * RSS indirection table. Currently unmodifable in FreeBSD. 138 */ 139 static const u_int rss_basecpu; 140 SYSCTL_INT(_net_inet_rss, OID_AUTO, basecpu, CTLFLAG_RD, 141 __DECONST(int *, &rss_basecpu), 0, "RSS base CPU"); 142 143 #endif 144 /* 145 * Print verbose debugging messages. 146 * 0 - disable 147 * non-zero - enable 148 */ 149 int rss_debug = 0; 150 SYSCTL_INT(_net_inet_rss, OID_AUTO, debug, CTLFLAG_RWTUN, &rss_debug, 0, 151 "RSS debug level"); 152 153 static u_int rss_udp_4tuple = 0; 154 SYSCTL_INT(_net_inet_rss, OID_AUTO, udp_4tuple, CTLFLAG_RDTUN, 155 &rss_udp_4tuple, 0, 156 "Enable UDP 4-tuple RSS hashing (src/dst IP + src/dst port)"); 157 158 /* 159 * RSS secret key, intended to prevent attacks on load-balancing. Its 160 * effectiveness may be limited by algorithm choice and available entropy 161 * during the boot. 162 * 163 * XXXRW: And that we don't randomize it yet! 164 * 165 * This is the default Microsoft RSS specification key which is also 166 * the Chelsio T5 firmware default key. 167 */ 168 static uint8_t rss_key[RSS_KEYSIZE] = { 169 0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x0e, 0xc2, 170 0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0, 171 0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4, 172 0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c, 173 0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa, 174 }; 175 176 #ifdef RSS 177 /* 178 * RSS hash->CPU table, which maps hashed packet headers to particular CPUs. 179 * Drivers may supplement this table with a separate CPU<->queue table when 180 * programming devices. 181 */ 182 struct rss_table_entry { 183 uint8_t rte_cpu; /* CPU affinity of bucket. */ 184 }; 185 static struct rss_table_entry rss_table[RSS_TABLE_MAXLEN]; 186 #endif 187 188 static void 189 rss_init(__unused void *arg) 190 { 191 #ifdef RSS 192 u_int i; 193 u_int cpuid; 194 #endif 195 /* 196 * Validate tunables, coerce to sensible values. 197 */ 198 switch (rss_hashalgo) { 199 case RSS_HASH_TOEPLITZ: 200 case RSS_HASH_NAIVE: 201 break; 202 203 default: 204 RSS_DEBUG("invalid RSS hashalgo %u, coercing to %u\n", 205 rss_hashalgo, RSS_HASH_TOEPLITZ); 206 rss_hashalgo = RSS_HASH_TOEPLITZ; 207 } 208 209 #ifdef RSS 210 /* 211 * Count available CPUs. 212 * 213 * XXXRW: Note incorrect assumptions regarding contiguity of this set 214 * elsewhere. 215 */ 216 rss_ncpus = 0; 217 for (i = 0; i <= mp_maxid; i++) { 218 if (CPU_ABSENT(i)) 219 continue; 220 rss_ncpus++; 221 } 222 if (rss_ncpus > RSS_MAXCPUS) 223 rss_ncpus = RSS_MAXCPUS; 224 225 /* 226 * Tune RSS table entries to be no less than 2x the number of CPUs 227 * -- unless we're running uniprocessor, in which case there's not 228 * much point in having buckets to rearrange for load-balancing! 229 */ 230 if (rss_ncpus > 1) { 231 if (rss_bits == 0) 232 rss_bits = fls(rss_ncpus - 1) + 1; 233 234 /* 235 * Microsoft limits RSS table entries to 128, so apply that 236 * limit to both auto-detected CPU counts and user-configured 237 * ones. 238 */ 239 if (rss_bits == 0 || rss_bits > RSS_MAXBITS) { 240 RSS_DEBUG("RSS bits %u not valid, coercing to %u\n", 241 rss_bits, RSS_MAXBITS); 242 rss_bits = RSS_MAXBITS; 243 } 244 245 /* 246 * Figure out how many buckets to use; warn if less than the 247 * number of configured CPUs, although this is not a fatal 248 * problem. 249 */ 250 rss_buckets = (1 << rss_bits); 251 if (rss_buckets < rss_ncpus) 252 RSS_DEBUG("WARNING: rss_buckets (%u) less than " 253 "rss_ncpus (%u)\n", rss_buckets, rss_ncpus); 254 rss_mask = rss_buckets - 1; 255 } else { 256 rss_bits = 0; 257 rss_buckets = 1; 258 rss_mask = 0; 259 } 260 261 /* 262 * Set up initial CPU assignments: round-robin by default. 263 */ 264 cpuid = CPU_FIRST(); 265 for (i = 0; i < rss_buckets; i++) { 266 rss_table[i].rte_cpu = cpuid; 267 cpuid = CPU_NEXT(cpuid); 268 } 269 #endif /* RSS */ 270 /* 271 * Randomize rrs_key. 272 * 273 * XXXRW: Not yet. If nothing else, will require an rss_isbadkey() 274 * loop to check for "bad" RSS keys. 275 */ 276 } 277 SYSINIT(rss_init, SI_SUB_SOFTINTR, SI_ORDER_SECOND, rss_init, NULL); 278 279 static uint32_t 280 rss_naive_hash(u_int keylen, const uint8_t *key, u_int datalen, 281 const uint8_t *data) 282 { 283 uint32_t v; 284 u_int i; 285 286 v = 0; 287 for (i = 0; i < keylen; i++) 288 v += key[i]; 289 for (i = 0; i < datalen; i++) 290 v += data[i]; 291 return (v); 292 } 293 294 uint32_t 295 rss_hash(u_int datalen, const uint8_t *data) 296 { 297 298 switch (rss_hashalgo) { 299 case RSS_HASH_TOEPLITZ: 300 return (toeplitz_hash(sizeof(rss_key), rss_key, datalen, 301 data)); 302 303 case RSS_HASH_NAIVE: 304 return (rss_naive_hash(sizeof(rss_key), rss_key, datalen, 305 data)); 306 307 default: 308 panic("%s: unsupported/unknown hashalgo %d", __func__, 309 rss_hashalgo); 310 } 311 } 312 313 /* 314 * Query the current RSS key; likely to be used by device drivers when 315 * configuring hardware RSS. Caller must pass an array of size RSS_KEYSIZE. 316 * 317 * XXXRW: Perhaps we should do the accept-a-length-and-truncate thing? 318 */ 319 void 320 rss_getkey(uint8_t *key) 321 { 322 323 bcopy(rss_key, key, sizeof(rss_key)); 324 } 325 326 /* 327 * Query the RSS hash algorithm. 328 */ 329 u_int 330 rss_gethashalgo(void) 331 { 332 333 return (rss_hashalgo); 334 } 335 336 #ifdef RSS 337 /* 338 * Query the number of RSS bits in use. 339 */ 340 u_int 341 rss_getbits(void) 342 { 343 344 return (rss_bits); 345 } 346 347 /* 348 * Query the RSS bucket associated with an RSS hash. 349 */ 350 u_int 351 rss_getbucket(u_int hash) 352 { 353 354 return (hash & rss_mask); 355 } 356 357 /* 358 * Query the RSS layer bucket associated with the given 359 * entry in the RSS hash space. 360 * 361 * The RSS indirection table is 0 .. rss_buckets-1, 362 * covering the low 'rss_bits' of the total 128 slot 363 * RSS indirection table. So just mask off rss_bits and 364 * return that. 365 * 366 * NIC drivers can then iterate over the 128 slot RSS 367 * indirection table and fetch which RSS bucket to 368 * map it to. This will typically be a CPU queue 369 */ 370 u_int 371 rss_get_indirection_to_bucket(u_int index) 372 { 373 374 return (index & rss_mask); 375 } 376 377 /* 378 * Query the RSS CPU associated with an RSS bucket. 379 */ 380 u_int 381 rss_getcpu(u_int bucket) 382 { 383 384 return (rss_table[bucket].rte_cpu); 385 } 386 387 /* 388 * netisr CPU affinity lookup given just the hash and hashtype. 389 */ 390 u_int 391 rss_hash2cpuid(uint32_t hash_val, uint32_t hash_type) 392 { 393 394 switch (hash_type) { 395 case M_HASHTYPE_RSS_IPV4: 396 case M_HASHTYPE_RSS_TCP_IPV4: 397 case M_HASHTYPE_RSS_UDP_IPV4: 398 case M_HASHTYPE_RSS_IPV6: 399 case M_HASHTYPE_RSS_TCP_IPV6: 400 case M_HASHTYPE_RSS_UDP_IPV6: 401 return (rss_getcpu(rss_getbucket(hash_val))); 402 default: 403 return (NETISR_CPUID_NONE); 404 } 405 } 406 407 /* 408 * Query the RSS bucket associated with the given hash value and 409 * type. 410 */ 411 int 412 rss_hash2bucket(uint32_t hash_val, uint32_t hash_type, uint32_t *bucket_id) 413 { 414 415 switch (hash_type) { 416 case M_HASHTYPE_RSS_IPV4: 417 case M_HASHTYPE_RSS_TCP_IPV4: 418 case M_HASHTYPE_RSS_UDP_IPV4: 419 case M_HASHTYPE_RSS_IPV6: 420 case M_HASHTYPE_RSS_TCP_IPV6: 421 case M_HASHTYPE_RSS_UDP_IPV6: 422 *bucket_id = rss_getbucket(hash_val); 423 return (0); 424 default: 425 return (-1); 426 } 427 } 428 429 /* 430 * netisr CPU affinity lookup routine for use by protocols. 431 */ 432 struct mbuf * 433 rss_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid) 434 { 435 436 M_ASSERTPKTHDR(m); 437 *cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m)); 438 return (m); 439 } 440 441 int 442 rss_m2bucket(struct mbuf *m, uint32_t *bucket_id) 443 { 444 445 M_ASSERTPKTHDR(m); 446 447 return(rss_hash2bucket(m->m_pkthdr.flowid, M_HASHTYPE_GET(m), 448 bucket_id)); 449 } 450 451 /* 452 * Query the number of buckets; this may be used by both network device 453 * drivers, which will need to populate hardware shadows of the software 454 * indirection table, and the network stack itself (such as when deciding how 455 * many connection groups to allocate). 456 */ 457 u_int 458 rss_getnumbuckets(void) 459 { 460 461 return (rss_buckets); 462 } 463 464 /* 465 * Query the number of CPUs in use by RSS; may be useful to device drivers 466 * trying to figure out how to map a larger number of CPUs into a smaller 467 * number of receive queues. 468 */ 469 u_int 470 rss_getnumcpus(void) 471 { 472 473 return (rss_ncpus); 474 } 475 476 #endif 477 /* 478 * Return the supported RSS hash configuration. 479 * 480 * NICs should query this to determine what to configure in their redirection 481 * matching table. 482 */ 483 inline u_int 484 rss_gethashconfig(void) 485 { 486 487 /* Return 4-tuple for TCP; 2-tuple for others */ 488 /* 489 * UDP may fragment more often than TCP and thus we'll end up with 490 * NICs returning 2-tuple fragments. 491 * udp_init() and udplite_init() both currently initialise things 492 * as 2-tuple. 493 * So for now disable UDP 4-tuple hashing until all of the other 494 * pieces are in place. 495 */ 496 u_int config; 497 498 config = 499 RSS_HASHTYPE_RSS_IPV4 500 | RSS_HASHTYPE_RSS_TCP_IPV4 501 | RSS_HASHTYPE_RSS_IPV6 502 | RSS_HASHTYPE_RSS_TCP_IPV6 503 | RSS_HASHTYPE_RSS_IPV6_EX 504 | RSS_HASHTYPE_RSS_TCP_IPV6_EX; 505 506 if (rss_udp_4tuple) { 507 config |= 508 RSS_HASHTYPE_RSS_UDP_IPV4 509 | RSS_HASHTYPE_RSS_UDP_IPV6 510 | RSS_HASHTYPE_RSS_UDP_IPV6_EX; 511 } 512 513 return (config); 514 } 515 516 /* 517 * XXXRW: Confirm that sysctl -a won't dump this keying material, don't want 518 * it appearing in debugging output unnecessarily. 519 */ 520 static int 521 sysctl_rss_key(SYSCTL_HANDLER_ARGS) 522 { 523 uint8_t temp_rss_key[RSS_KEYSIZE]; 524 int error; 525 526 error = priv_check(req->td, PRIV_NETINET_HASHKEY); 527 if (error) 528 return (error); 529 530 bcopy(rss_key, temp_rss_key, sizeof(temp_rss_key)); 531 error = sysctl_handle_opaque(oidp, temp_rss_key, 532 sizeof(temp_rss_key), req); 533 if (error) 534 return (error); 535 if (req->newptr != NULL) { 536 /* XXXRW: Not yet. */ 537 return (EINVAL); 538 } 539 return (0); 540 } 541 SYSCTL_PROC(_net_inet_rss, OID_AUTO, key, 542 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, sysctl_rss_key, 543 "", "RSS keying material"); 544 545 #ifdef RSS 546 static int 547 sysctl_rss_bucket_mapping(SYSCTL_HANDLER_ARGS) 548 { 549 struct sbuf *sb; 550 int error; 551 int i; 552 553 error = 0; 554 error = sysctl_wire_old_buffer(req, 0); 555 if (error != 0) 556 return (error); 557 sb = sbuf_new_for_sysctl(NULL, NULL, 512, req); 558 if (sb == NULL) 559 return (ENOMEM); 560 for (i = 0; i < rss_buckets; i++) { 561 sbuf_printf(sb, "%s%d:%d", i == 0 ? "" : " ", 562 i, 563 rss_getcpu(i)); 564 } 565 error = sbuf_finish(sb); 566 sbuf_delete(sb); 567 568 return (error); 569 } 570 SYSCTL_PROC(_net_inet_rss, OID_AUTO, bucket_mapping, 571 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 572 sysctl_rss_bucket_mapping, "", "RSS bucket -> CPU mapping"); 573 #endif 574