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 #include <sys/cdefs.h>
31
32 __FBSDID("$FreeBSD$");
33
34 #include "opt_inet6.h"
35 #include "opt_pcbgroup.h"
36
37 #ifndef PCBGROUP
38 #error "options RSS depends on options PCBGROUP"
39 #endif
40
41 #include <sys/param.h>
42 #include <sys/mbuf.h>
43 #include <sys/socket.h>
44 #include <sys/priv.h>
45 #include <sys/kernel.h>
46 #include <sys/smp.h>
47 #include <sys/sysctl.h>
48 #include <sys/sbuf.h>
49
50 #include <net/if.h>
51 #include <net/if_var.h>
52 #include <net/netisr.h>
53 #include <net/rss_config.h>
54 #include <net/toeplitz.h>
55
56 /*-
57 * Operating system parts of receiver-side scaling (RSS), which allows
58 * network cards to direct flows to particular receive queues based on hashes
59 * of header tuples. This implementation aligns RSS buckets with connection
60 * groups at the TCP/IP layer, so each bucket is associated with exactly one
61 * group. As a result, the group lookup structures (and lock) should have an
62 * effective affinity with exactly one CPU.
63 *
64 * Network device drivers needing to configure RSS will query this framework
65 * for parameters, such as the current RSS key, hashing policies, number of
66 * bits, and indirection table mapping hashes to buckets and CPUs. They may
67 * provide their own supplementary information, such as queue<->CPU bindings.
68 * It is the responsibility of the network device driver to inject packets
69 * into the stack on as close to the right CPU as possible, if playing by RSS
70 * rules.
71 *
72 * TODO:
73 *
74 * - Synchronization for rss_key and other future-configurable parameters.
75 * - Event handler drivers can register to pick up RSS configuration changes.
76 * - Should we allow rss_basecpu to be configured?
77 * - Randomize key on boot.
78 * - IPv6 support.
79 * - Statistics on how often there's a misalignment between hardware
80 * placement and pcbgroup expectations.
81 */
82
83 SYSCTL_DECL(_net_inet);
84 SYSCTL_NODE(_net_inet, OID_AUTO, rss, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
85 "Receive-side steering");
86
87 /*
88 * Toeplitz is the only required hash function in the RSS spec, so use it by
89 * default.
90 */
91 static u_int rss_hashalgo = RSS_HASH_TOEPLITZ;
92 SYSCTL_INT(_net_inet_rss, OID_AUTO, hashalgo, CTLFLAG_RDTUN, &rss_hashalgo, 0,
93 "RSS hash algorithm");
94
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 /*
144 * Print verbose debugging messages.
145 * 0 - disable
146 * non-zero - enable
147 */
148 int rss_debug = 0;
149 SYSCTL_INT(_net_inet_rss, OID_AUTO, debug, CTLFLAG_RWTUN, &rss_debug, 0,
150 "RSS debug level");
151
152 /*
153 * RSS secret key, intended to prevent attacks on load-balancing. Its
154 * effectiveness may be limited by algorithm choice and available entropy
155 * during the boot.
156 *
157 * XXXRW: And that we don't randomize it yet!
158 *
159 * This is the default Microsoft RSS specification key which is also
160 * the Chelsio T5 firmware default key.
161 */
162 static uint8_t rss_key[RSS_KEYSIZE] = {
163 0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x0e, 0xc2,
164 0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0,
165 0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4,
166 0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c,
167 0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa,
168 };
169
170 /*
171 * RSS hash->CPU table, which maps hashed packet headers to particular CPUs.
172 * Drivers may supplement this table with a separate CPU<->queue table when
173 * programming devices.
174 */
175 struct rss_table_entry {
176 uint8_t rte_cpu; /* CPU affinity of bucket. */
177 };
178 static struct rss_table_entry rss_table[RSS_TABLE_MAXLEN];
179
180 static void
rss_init(__unused void * arg)181 rss_init(__unused void *arg)
182 {
183 u_int i;
184 u_int cpuid;
185
186 /*
187 * Validate tunables, coerce to sensible values.
188 */
189 switch (rss_hashalgo) {
190 case RSS_HASH_TOEPLITZ:
191 case RSS_HASH_NAIVE:
192 break;
193
194 default:
195 RSS_DEBUG("invalid RSS hashalgo %u, coercing to %u\n",
196 rss_hashalgo, RSS_HASH_TOEPLITZ);
197 rss_hashalgo = RSS_HASH_TOEPLITZ;
198 }
199
200 /*
201 * Count available CPUs.
202 *
203 * XXXRW: Note incorrect assumptions regarding contiguity of this set
204 * elsewhere.
205 */
206 rss_ncpus = 0;
207 for (i = 0; i <= mp_maxid; i++) {
208 if (CPU_ABSENT(i))
209 continue;
210 rss_ncpus++;
211 }
212 if (rss_ncpus > RSS_MAXCPUS)
213 rss_ncpus = RSS_MAXCPUS;
214
215 /*
216 * Tune RSS table entries to be no less than 2x the number of CPUs
217 * -- unless we're running uniprocessor, in which case there's not
218 * much point in having buckets to rearrange for load-balancing!
219 */
220 if (rss_ncpus > 1) {
221 if (rss_bits == 0)
222 rss_bits = fls(rss_ncpus - 1) + 1;
223
224 /*
225 * Microsoft limits RSS table entries to 128, so apply that
226 * limit to both auto-detected CPU counts and user-configured
227 * ones.
228 */
229 if (rss_bits == 0 || rss_bits > RSS_MAXBITS) {
230 RSS_DEBUG("RSS bits %u not valid, coercing to %u\n",
231 rss_bits, RSS_MAXBITS);
232 rss_bits = RSS_MAXBITS;
233 }
234
235 /*
236 * Figure out how many buckets to use; warn if less than the
237 * number of configured CPUs, although this is not a fatal
238 * problem.
239 */
240 rss_buckets = (1 << rss_bits);
241 if (rss_buckets < rss_ncpus)
242 RSS_DEBUG("WARNING: rss_buckets (%u) less than "
243 "rss_ncpus (%u)\n", rss_buckets, rss_ncpus);
244 rss_mask = rss_buckets - 1;
245 } else {
246 rss_bits = 0;
247 rss_buckets = 1;
248 rss_mask = 0;
249 }
250
251 /*
252 * Set up initial CPU assignments: round-robin by default.
253 */
254 cpuid = CPU_FIRST();
255 for (i = 0; i < rss_buckets; i++) {
256 rss_table[i].rte_cpu = cpuid;
257 cpuid = CPU_NEXT(cpuid);
258 }
259
260 /*
261 * Randomize rrs_key.
262 *
263 * XXXRW: Not yet. If nothing else, will require an rss_isbadkey()
264 * loop to check for "bad" RSS keys.
265 */
266 }
267 SYSINIT(rss_init, SI_SUB_SOFTINTR, SI_ORDER_SECOND, rss_init, NULL);
268
269 static uint32_t
rss_naive_hash(u_int keylen,const uint8_t * key,u_int datalen,const uint8_t * data)270 rss_naive_hash(u_int keylen, const uint8_t *key, u_int datalen,
271 const uint8_t *data)
272 {
273 uint32_t v;
274 u_int i;
275
276 v = 0;
277 for (i = 0; i < keylen; i++)
278 v += key[i];
279 for (i = 0; i < datalen; i++)
280 v += data[i];
281 return (v);
282 }
283
284 uint32_t
rss_hash(u_int datalen,const uint8_t * data)285 rss_hash(u_int datalen, const uint8_t *data)
286 {
287
288 switch (rss_hashalgo) {
289 case RSS_HASH_TOEPLITZ:
290 return (toeplitz_hash(sizeof(rss_key), rss_key, datalen,
291 data));
292
293 case RSS_HASH_NAIVE:
294 return (rss_naive_hash(sizeof(rss_key), rss_key, datalen,
295 data));
296
297 default:
298 panic("%s: unsupported/unknown hashalgo %d", __func__,
299 rss_hashalgo);
300 }
301 }
302
303 /*
304 * Query the number of RSS bits in use.
305 */
306 u_int
rss_getbits(void)307 rss_getbits(void)
308 {
309
310 return (rss_bits);
311 }
312
313 /*
314 * Query the RSS bucket associated with an RSS hash.
315 */
316 u_int
rss_getbucket(u_int hash)317 rss_getbucket(u_int hash)
318 {
319
320 return (hash & rss_mask);
321 }
322
323 /*
324 * Query the RSS layer bucket associated with the given
325 * entry in the RSS hash space.
326 *
327 * The RSS indirection table is 0 .. rss_buckets-1,
328 * covering the low 'rss_bits' of the total 128 slot
329 * RSS indirection table. So just mask off rss_bits and
330 * return that.
331 *
332 * NIC drivers can then iterate over the 128 slot RSS
333 * indirection table and fetch which RSS bucket to
334 * map it to. This will typically be a CPU queue
335 */
336 u_int
rss_get_indirection_to_bucket(u_int index)337 rss_get_indirection_to_bucket(u_int index)
338 {
339
340 return (index & rss_mask);
341 }
342
343 /*
344 * Query the RSS CPU associated with an RSS bucket.
345 */
346 u_int
rss_getcpu(u_int bucket)347 rss_getcpu(u_int bucket)
348 {
349
350 return (rss_table[bucket].rte_cpu);
351 }
352
353 /*
354 * netisr CPU affinity lookup given just the hash and hashtype.
355 */
356 u_int
rss_hash2cpuid(uint32_t hash_val,uint32_t hash_type)357 rss_hash2cpuid(uint32_t hash_val, uint32_t hash_type)
358 {
359
360 switch (hash_type) {
361 case M_HASHTYPE_RSS_IPV4:
362 case M_HASHTYPE_RSS_TCP_IPV4:
363 case M_HASHTYPE_RSS_UDP_IPV4:
364 case M_HASHTYPE_RSS_IPV6:
365 case M_HASHTYPE_RSS_TCP_IPV6:
366 case M_HASHTYPE_RSS_UDP_IPV6:
367 return (rss_getcpu(rss_getbucket(hash_val)));
368 default:
369 return (NETISR_CPUID_NONE);
370 }
371 }
372
373 /*
374 * Query the RSS bucket associated with the given hash value and
375 * type.
376 */
377 int
rss_hash2bucket(uint32_t hash_val,uint32_t hash_type,uint32_t * bucket_id)378 rss_hash2bucket(uint32_t hash_val, uint32_t hash_type, uint32_t *bucket_id)
379 {
380
381 switch (hash_type) {
382 case M_HASHTYPE_RSS_IPV4:
383 case M_HASHTYPE_RSS_TCP_IPV4:
384 case M_HASHTYPE_RSS_UDP_IPV4:
385 case M_HASHTYPE_RSS_IPV6:
386 case M_HASHTYPE_RSS_TCP_IPV6:
387 case M_HASHTYPE_RSS_UDP_IPV6:
388 *bucket_id = rss_getbucket(hash_val);
389 return (0);
390 default:
391 return (-1);
392 }
393 }
394
395 /*
396 * netisr CPU affinity lookup routine for use by protocols.
397 */
398 struct mbuf *
rss_m2cpuid(struct mbuf * m,uintptr_t source,u_int * cpuid)399 rss_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid)
400 {
401
402 M_ASSERTPKTHDR(m);
403 *cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m));
404 return (m);
405 }
406
407 int
rss_m2bucket(struct mbuf * m,uint32_t * bucket_id)408 rss_m2bucket(struct mbuf *m, uint32_t *bucket_id)
409 {
410
411 M_ASSERTPKTHDR(m);
412
413 return(rss_hash2bucket(m->m_pkthdr.flowid, M_HASHTYPE_GET(m),
414 bucket_id));
415 }
416
417 /*
418 * Query the RSS hash algorithm.
419 */
420 u_int
rss_gethashalgo(void)421 rss_gethashalgo(void)
422 {
423
424 return (rss_hashalgo);
425 }
426
427 /*
428 * Query the current RSS key; likely to be used by device drivers when
429 * configuring hardware RSS. Caller must pass an array of size RSS_KEYSIZE.
430 *
431 * XXXRW: Perhaps we should do the accept-a-length-and-truncate thing?
432 */
433 void
rss_getkey(uint8_t * key)434 rss_getkey(uint8_t *key)
435 {
436
437 bcopy(rss_key, key, sizeof(rss_key));
438 }
439
440 /*
441 * Query the number of buckets; this may be used by both network device
442 * drivers, which will need to populate hardware shadows of the software
443 * indirection table, and the network stack itself (such as when deciding how
444 * many connection groups to allocate).
445 */
446 u_int
rss_getnumbuckets(void)447 rss_getnumbuckets(void)
448 {
449
450 return (rss_buckets);
451 }
452
453 /*
454 * Query the number of CPUs in use by RSS; may be useful to device drivers
455 * trying to figure out how to map a larger number of CPUs into a smaller
456 * number of receive queues.
457 */
458 u_int
rss_getnumcpus(void)459 rss_getnumcpus(void)
460 {
461
462 return (rss_ncpus);
463 }
464
465 /*
466 * Return the supported RSS hash configuration.
467 *
468 * NICs should query this to determine what to configure in their redirection
469 * matching table.
470 */
471 inline u_int
rss_gethashconfig(void)472 rss_gethashconfig(void)
473 {
474
475 /* Return 4-tuple for TCP; 2-tuple for others */
476 /*
477 * UDP may fragment more often than TCP and thus we'll end up with
478 * NICs returning 2-tuple fragments.
479 * udp_init() and udplite_init() both currently initialise things
480 * as 2-tuple.
481 * So for now disable UDP 4-tuple hashing until all of the other
482 * pieces are in place.
483 */
484 return (
485 RSS_HASHTYPE_RSS_IPV4
486 | RSS_HASHTYPE_RSS_TCP_IPV4
487 | RSS_HASHTYPE_RSS_IPV6
488 | RSS_HASHTYPE_RSS_TCP_IPV6
489 | RSS_HASHTYPE_RSS_IPV6_EX
490 | RSS_HASHTYPE_RSS_TCP_IPV6_EX
491 #if 0
492 | RSS_HASHTYPE_RSS_UDP_IPV4
493 | RSS_HASHTYPE_RSS_UDP_IPV6
494 | RSS_HASHTYPE_RSS_UDP_IPV6_EX
495 #endif
496 );
497 }
498
499 /*
500 * XXXRW: Confirm that sysctl -a won't dump this keying material, don't want
501 * it appearing in debugging output unnecessarily.
502 */
503 static int
sysctl_rss_key(SYSCTL_HANDLER_ARGS)504 sysctl_rss_key(SYSCTL_HANDLER_ARGS)
505 {
506 uint8_t temp_rss_key[RSS_KEYSIZE];
507 int error;
508
509 error = priv_check(req->td, PRIV_NETINET_HASHKEY);
510 if (error)
511 return (error);
512
513 bcopy(rss_key, temp_rss_key, sizeof(temp_rss_key));
514 error = sysctl_handle_opaque(oidp, temp_rss_key,
515 sizeof(temp_rss_key), req);
516 if (error)
517 return (error);
518 if (req->newptr != NULL) {
519 /* XXXRW: Not yet. */
520 return (EINVAL);
521 }
522 return (0);
523 }
524 SYSCTL_PROC(_net_inet_rss, OID_AUTO, key,
525 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, sysctl_rss_key,
526 "", "RSS keying material");
527
528 static int
sysctl_rss_bucket_mapping(SYSCTL_HANDLER_ARGS)529 sysctl_rss_bucket_mapping(SYSCTL_HANDLER_ARGS)
530 {
531 struct sbuf *sb;
532 int error;
533 int i;
534
535 error = 0;
536 error = sysctl_wire_old_buffer(req, 0);
537 if (error != 0)
538 return (error);
539 sb = sbuf_new_for_sysctl(NULL, NULL, 512, req);
540 if (sb == NULL)
541 return (ENOMEM);
542 for (i = 0; i < rss_buckets; i++) {
543 sbuf_printf(sb, "%s%d:%d", i == 0 ? "" : " ",
544 i,
545 rss_getcpu(i));
546 }
547 error = sbuf_finish(sb);
548 sbuf_delete(sb);
549
550 return (error);
551 }
552 SYSCTL_PROC(_net_inet_rss, OID_AUTO, bucket_mapping,
553 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
554 sysctl_rss_bucket_mapping, "", "RSS bucket -> CPU mapping");
555