/*- * Copyright (c) 2010-2011 Juniper Networks, Inc. * All rights reserved. * * This software was developed by Robert N. M. Watson under contract * to Juniper Networks, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include "opt_inet6.h" #include <sys/param.h> #include <sys/mbuf.h> #include <sys/socket.h> #include <sys/priv.h> #include <sys/kernel.h> #include <sys/smp.h> #include <sys/sysctl.h> #include <sys/sbuf.h> #include <net/if.h> #include <net/if_var.h> #include <net/netisr.h> #include <net/rss_config.h> #include <net/toeplitz.h> /*- * Operating system parts of receiver-side scaling (RSS), which allows * network cards to direct flows to particular receive queues based on hashes * of header tuples. This implementation aligns RSS buckets with connection * groups at the TCP/IP layer, so each bucket is associated with exactly one * group. As a result, the group lookup structures (and lock) should have an * effective affinity with exactly one CPU. * * Network device drivers needing to configure RSS will query this framework * for parameters, such as the current RSS key, hashing policies, number of * bits, and indirection table mapping hashes to buckets and CPUs. They may * provide their own supplementary information, such as queue<->CPU bindings. * It is the responsibility of the network device driver to inject packets * into the stack on as close to the right CPU as possible, if playing by RSS * rules. * * TODO: * * - Synchronization for rss_key and other future-configurable parameters. * - Event handler drivers can register to pick up RSS configuration changes. * - Should we allow rss_basecpu to be configured? * - Randomize key on boot. * - IPv6 support. * - Statistics on how often there's a misalignment between hardware * placement and pcbgroup expectations. */ SYSCTL_DECL(_net_inet); SYSCTL_NODE(_net_inet, OID_AUTO, rss, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, "Receive-side steering"); /* * Toeplitz is the only required hash function in the RSS spec, so use it by * default. */ static u_int rss_hashalgo = RSS_HASH_TOEPLITZ; SYSCTL_INT(_net_inet_rss, OID_AUTO, hashalgo, CTLFLAG_RDTUN, &rss_hashalgo, 0, "RSS hash algorithm"); /* * Size of the indirection table; at most 128 entries per the RSS spec. We * size it to at least 2 times the number of CPUs by default to allow useful * rebalancing. If not set explicitly with a loader tunable, we tune based * on the number of CPUs present. * * XXXRW: buckets might be better to use for the tunable than bits. */ static u_int rss_bits; SYSCTL_INT(_net_inet_rss, OID_AUTO, bits, CTLFLAG_RDTUN, &rss_bits, 0, "RSS bits"); static u_int rss_mask; SYSCTL_INT(_net_inet_rss, OID_AUTO, mask, CTLFLAG_RD, &rss_mask, 0, "RSS mask"); static const u_int rss_maxbits = RSS_MAXBITS; SYSCTL_INT(_net_inet_rss, OID_AUTO, maxbits, CTLFLAG_RD, __DECONST(int *, &rss_maxbits), 0, "RSS maximum bits"); /* * RSS's own count of the number of CPUs it could be using for processing. * Bounded to 64 by RSS constants. */ static u_int rss_ncpus; SYSCTL_INT(_net_inet_rss, OID_AUTO, ncpus, CTLFLAG_RD, &rss_ncpus, 0, "Number of CPUs available to RSS"); #define RSS_MAXCPUS (1 << (RSS_MAXBITS - 1)) static const u_int rss_maxcpus = RSS_MAXCPUS; SYSCTL_INT(_net_inet_rss, OID_AUTO, maxcpus, CTLFLAG_RD, __DECONST(int *, &rss_maxcpus), 0, "RSS maximum CPUs that can be used"); /* * Variable exists just for reporting rss_bits in a user-friendly way. */ static u_int rss_buckets; SYSCTL_INT(_net_inet_rss, OID_AUTO, buckets, CTLFLAG_RD, &rss_buckets, 0, "RSS buckets"); /* * Base CPU number; devices will add this to all CPU numbers returned by the * RSS indirection table. Currently unmodifable in FreeBSD. */ static const u_int rss_basecpu; SYSCTL_INT(_net_inet_rss, OID_AUTO, basecpu, CTLFLAG_RD, __DECONST(int *, &rss_basecpu), 0, "RSS base CPU"); /* * Print verbose debugging messages. * 0 - disable * non-zero - enable */ int rss_debug = 0; SYSCTL_INT(_net_inet_rss, OID_AUTO, debug, CTLFLAG_RWTUN, &rss_debug, 0, "RSS debug level"); /* * RSS secret key, intended to prevent attacks on load-balancing. Its * effectiveness may be limited by algorithm choice and available entropy * during the boot. * * XXXRW: And that we don't randomize it yet! * * This is the default Microsoft RSS specification key which is also * the Chelsio T5 firmware default key. */ static uint8_t rss_key[RSS_KEYSIZE] = { 0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x0e, 0xc2, 0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0, 0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4, 0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c, 0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa, }; /* * RSS hash->CPU table, which maps hashed packet headers to particular CPUs. * Drivers may supplement this table with a separate CPU<->queue table when * programming devices. */ struct rss_table_entry { uint8_t rte_cpu; /* CPU affinity of bucket. */ }; static struct rss_table_entry rss_table[RSS_TABLE_MAXLEN]; static void rss_init(__unused void *arg) { u_int i; u_int cpuid; /* * Validate tunables, coerce to sensible values. */ switch (rss_hashalgo) { case RSS_HASH_TOEPLITZ: case RSS_HASH_NAIVE: break; default: RSS_DEBUG("invalid RSS hashalgo %u, coercing to %u\n", rss_hashalgo, RSS_HASH_TOEPLITZ); rss_hashalgo = RSS_HASH_TOEPLITZ; } /* * Count available CPUs. * * XXXRW: Note incorrect assumptions regarding contiguity of this set * elsewhere. */ rss_ncpus = 0; for (i = 0; i <= mp_maxid; i++) { if (CPU_ABSENT(i)) continue; rss_ncpus++; } if (rss_ncpus > RSS_MAXCPUS) rss_ncpus = RSS_MAXCPUS; /* * Tune RSS table entries to be no less than 2x the number of CPUs * -- unless we're running uniprocessor, in which case there's not * much point in having buckets to rearrange for load-balancing! */ if (rss_ncpus > 1) { if (rss_bits == 0) rss_bits = fls(rss_ncpus - 1) + 1; /* * Microsoft limits RSS table entries to 128, so apply that * limit to both auto-detected CPU counts and user-configured * ones. */ if (rss_bits == 0 || rss_bits > RSS_MAXBITS) { RSS_DEBUG("RSS bits %u not valid, coercing to %u\n", rss_bits, RSS_MAXBITS); rss_bits = RSS_MAXBITS; } /* * Figure out how many buckets to use; warn if less than the * number of configured CPUs, although this is not a fatal * problem. */ rss_buckets = (1 << rss_bits); if (rss_buckets < rss_ncpus) RSS_DEBUG("WARNING: rss_buckets (%u) less than " "rss_ncpus (%u)\n", rss_buckets, rss_ncpus); rss_mask = rss_buckets - 1; } else { rss_bits = 0; rss_buckets = 1; rss_mask = 0; } /* * Set up initial CPU assignments: round-robin by default. */ cpuid = CPU_FIRST(); for (i = 0; i < rss_buckets; i++) { rss_table[i].rte_cpu = cpuid; cpuid = CPU_NEXT(cpuid); } /* * Randomize rrs_key. * * XXXRW: Not yet. If nothing else, will require an rss_isbadkey() * loop to check for "bad" RSS keys. */ } SYSINIT(rss_init, SI_SUB_SOFTINTR, SI_ORDER_SECOND, rss_init, NULL); static uint32_t rss_naive_hash(u_int keylen, const uint8_t *key, u_int datalen, const uint8_t *data) { uint32_t v; u_int i; v = 0; for (i = 0; i < keylen; i++) v += key[i]; for (i = 0; i < datalen; i++) v += data[i]; return (v); } uint32_t rss_hash(u_int datalen, const uint8_t *data) { switch (rss_hashalgo) { case RSS_HASH_TOEPLITZ: return (toeplitz_hash(sizeof(rss_key), rss_key, datalen, data)); case RSS_HASH_NAIVE: return (rss_naive_hash(sizeof(rss_key), rss_key, datalen, data)); default: panic("%s: unsupported/unknown hashalgo %d", __func__, rss_hashalgo); } } /* * Query the number of RSS bits in use. */ u_int rss_getbits(void) { return (rss_bits); } /* * Query the RSS bucket associated with an RSS hash. */ u_int rss_getbucket(u_int hash) { return (hash & rss_mask); } /* * Query the RSS layer bucket associated with the given * entry in the RSS hash space. * * The RSS indirection table is 0 .. rss_buckets-1, * covering the low 'rss_bits' of the total 128 slot * RSS indirection table. So just mask off rss_bits and * return that. * * NIC drivers can then iterate over the 128 slot RSS * indirection table and fetch which RSS bucket to * map it to. This will typically be a CPU queue */ u_int rss_get_indirection_to_bucket(u_int index) { return (index & rss_mask); } /* * Query the RSS CPU associated with an RSS bucket. */ u_int rss_getcpu(u_int bucket) { return (rss_table[bucket].rte_cpu); } /* * netisr CPU affinity lookup given just the hash and hashtype. */ u_int rss_hash2cpuid(uint32_t hash_val, uint32_t hash_type) { switch (hash_type) { case M_HASHTYPE_RSS_IPV4: case M_HASHTYPE_RSS_TCP_IPV4: case M_HASHTYPE_RSS_UDP_IPV4: case M_HASHTYPE_RSS_IPV6: case M_HASHTYPE_RSS_TCP_IPV6: case M_HASHTYPE_RSS_UDP_IPV6: return (rss_getcpu(rss_getbucket(hash_val))); default: return (NETISR_CPUID_NONE); } } /* * Query the RSS bucket associated with the given hash value and * type. */ int rss_hash2bucket(uint32_t hash_val, uint32_t hash_type, uint32_t *bucket_id) { switch (hash_type) { case M_HASHTYPE_RSS_IPV4: case M_HASHTYPE_RSS_TCP_IPV4: case M_HASHTYPE_RSS_UDP_IPV4: case M_HASHTYPE_RSS_IPV6: case M_HASHTYPE_RSS_TCP_IPV6: case M_HASHTYPE_RSS_UDP_IPV6: *bucket_id = rss_getbucket(hash_val); return (0); default: return (-1); } } /* * netisr CPU affinity lookup routine for use by protocols. */ struct mbuf * rss_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid) { M_ASSERTPKTHDR(m); *cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m)); return (m); } int rss_m2bucket(struct mbuf *m, uint32_t *bucket_id) { M_ASSERTPKTHDR(m); return(rss_hash2bucket(m->m_pkthdr.flowid, M_HASHTYPE_GET(m), bucket_id)); } /* * Query the RSS hash algorithm. */ u_int rss_gethashalgo(void) { return (rss_hashalgo); } /* * Query the current RSS key; likely to be used by device drivers when * configuring hardware RSS. Caller must pass an array of size RSS_KEYSIZE. * * XXXRW: Perhaps we should do the accept-a-length-and-truncate thing? */ void rss_getkey(uint8_t *key) { bcopy(rss_key, key, sizeof(rss_key)); } /* * Query the number of buckets; this may be used by both network device * drivers, which will need to populate hardware shadows of the software * indirection table, and the network stack itself (such as when deciding how * many connection groups to allocate). */ u_int rss_getnumbuckets(void) { return (rss_buckets); } /* * Query the number of CPUs in use by RSS; may be useful to device drivers * trying to figure out how to map a larger number of CPUs into a smaller * number of receive queues. */ u_int rss_getnumcpus(void) { return (rss_ncpus); } /* * Return the supported RSS hash configuration. * * NICs should query this to determine what to configure in their redirection * matching table. */ inline u_int rss_gethashconfig(void) { /* Return 4-tuple for TCP; 2-tuple for others */ /* * UDP may fragment more often than TCP and thus we'll end up with * NICs returning 2-tuple fragments. * udp_init() and udplite_init() both currently initialise things * as 2-tuple. * So for now disable UDP 4-tuple hashing until all of the other * pieces are in place. */ return ( RSS_HASHTYPE_RSS_IPV4 | RSS_HASHTYPE_RSS_TCP_IPV4 | RSS_HASHTYPE_RSS_IPV6 | RSS_HASHTYPE_RSS_TCP_IPV6 | RSS_HASHTYPE_RSS_IPV6_EX | RSS_HASHTYPE_RSS_TCP_IPV6_EX #if 0 | RSS_HASHTYPE_RSS_UDP_IPV4 | RSS_HASHTYPE_RSS_UDP_IPV6 | RSS_HASHTYPE_RSS_UDP_IPV6_EX #endif ); } /* * XXXRW: Confirm that sysctl -a won't dump this keying material, don't want * it appearing in debugging output unnecessarily. */ static int sysctl_rss_key(SYSCTL_HANDLER_ARGS) { uint8_t temp_rss_key[RSS_KEYSIZE]; int error; error = priv_check(req->td, PRIV_NETINET_HASHKEY); if (error) return (error); bcopy(rss_key, temp_rss_key, sizeof(temp_rss_key)); error = sysctl_handle_opaque(oidp, temp_rss_key, sizeof(temp_rss_key), req); if (error) return (error); if (req->newptr != NULL) { /* XXXRW: Not yet. */ return (EINVAL); } return (0); } SYSCTL_PROC(_net_inet_rss, OID_AUTO, key, CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, sysctl_rss_key, "", "RSS keying material"); static int sysctl_rss_bucket_mapping(SYSCTL_HANDLER_ARGS) { struct sbuf *sb; int error; int i; error = 0; error = sysctl_wire_old_buffer(req, 0); if (error != 0) return (error); sb = sbuf_new_for_sysctl(NULL, NULL, 512, req); if (sb == NULL) return (ENOMEM); for (i = 0; i < rss_buckets; i++) { sbuf_printf(sb, "%s%d:%d", i == 0 ? "" : " ", i, rss_getcpu(i)); } error = sbuf_finish(sb); sbuf_delete(sb); return (error); } SYSCTL_PROC(_net_inet_rss, OID_AUTO, bucket_mapping, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, sysctl_rss_bucket_mapping, "", "RSS bucket -> CPU mapping");