/*-
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet6.h"
#include "opt_pcbgroup.h"
#ifndef PCBGROUP
#error "options RSS depends on options PCBGROUP"
#endif
#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");
