555 lines
14 KiB
C
555 lines
14 KiB
C
/*-
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* Copyright (c) 2010-2011 Juniper Networks, Inc.
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* All rights reserved.
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*
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* This software was developed by Robert N. M. Watson under contract
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* to Juniper Networks, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet6.h"
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#include "opt_pcbgroup.h"
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#ifndef PCBGROUP
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#error "options RSS depends on options PCBGROUP"
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#endif
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#include <sys/param.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/priv.h>
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#include <sys/kernel.h>
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#include <sys/smp.h>
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#include <sys/sysctl.h>
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#include <sys/sbuf.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/netisr.h>
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#include <net/rss_config.h>
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#include <net/toeplitz.h>
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/*-
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* Operating system parts of receiver-side scaling (RSS), which allows
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* network cards to direct flows to particular receive queues based on hashes
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* of header tuples. This implementation aligns RSS buckets with connection
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* groups at the TCP/IP layer, so each bucket is associated with exactly one
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* group. As a result, the group lookup structures (and lock) should have an
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* effective affinity with exactly one CPU.
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*
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* Network device drivers needing to configure RSS will query this framework
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* for parameters, such as the current RSS key, hashing policies, number of
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* bits, and indirection table mapping hashes to buckets and CPUs. They may
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* provide their own supplementary information, such as queue<->CPU bindings.
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* It is the responsibility of the network device driver to inject packets
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* into the stack on as close to the right CPU as possible, if playing by RSS
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* rules.
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*
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* TODO:
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*
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* - Synchronization for rss_key and other future-configurable parameters.
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* - Event handler drivers can register to pick up RSS configuration changes.
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* - Should we allow rss_basecpu to be configured?
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* - Randomize key on boot.
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* - IPv6 support.
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* - Statistics on how often there's a misalignment between hardware
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* placement and pcbgroup expectations.
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*/
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SYSCTL_DECL(_net_inet);
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SYSCTL_NODE(_net_inet, OID_AUTO, rss, CTLFLAG_RW, 0, "Receive-side steering");
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/*
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* Toeplitz is the only required hash function in the RSS spec, so use it by
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* default.
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*/
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static u_int rss_hashalgo = RSS_HASH_TOEPLITZ;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, hashalgo, CTLFLAG_RDTUN, &rss_hashalgo, 0,
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"RSS hash algorithm");
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/*
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* Size of the indirection table; at most 128 entries per the RSS spec. We
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* size it to at least 2 times the number of CPUs by default to allow useful
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* rebalancing. If not set explicitly with a loader tunable, we tune based
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* on the number of CPUs present.
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*
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* XXXRW: buckets might be better to use for the tunable than bits.
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*/
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static u_int rss_bits;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, bits, CTLFLAG_RDTUN, &rss_bits, 0,
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"RSS bits");
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static u_int rss_mask;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, mask, CTLFLAG_RD, &rss_mask, 0,
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"RSS mask");
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static const u_int rss_maxbits = RSS_MAXBITS;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, maxbits, CTLFLAG_RD,
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__DECONST(int *, &rss_maxbits), 0, "RSS maximum bits");
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/*
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* RSS's own count of the number of CPUs it could be using for processing.
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* Bounded to 64 by RSS constants.
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*/
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static u_int rss_ncpus;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, ncpus, CTLFLAG_RD, &rss_ncpus, 0,
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"Number of CPUs available to RSS");
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#define RSS_MAXCPUS (1 << (RSS_MAXBITS - 1))
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static const u_int rss_maxcpus = RSS_MAXCPUS;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, maxcpus, CTLFLAG_RD,
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__DECONST(int *, &rss_maxcpus), 0, "RSS maximum CPUs that can be used");
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/*
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* Variable exists just for reporting rss_bits in a user-friendly way.
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*/
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static u_int rss_buckets;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, buckets, CTLFLAG_RD, &rss_buckets, 0,
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"RSS buckets");
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/*
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* Base CPU number; devices will add this to all CPU numbers returned by the
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* RSS indirection table. Currently unmodifable in FreeBSD.
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*/
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static const u_int rss_basecpu;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, basecpu, CTLFLAG_RD,
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__DECONST(int *, &rss_basecpu), 0, "RSS base CPU");
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/*
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* Print verbose debugging messages.
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* 0 - disable
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* non-zero - enable
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*/
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int rss_debug = 0;
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SYSCTL_INT(_net_inet_rss, OID_AUTO, debug, CTLFLAG_RWTUN, &rss_debug, 0,
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"RSS debug level");
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/*
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* RSS secret key, intended to prevent attacks on load-balancing. Its
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* effectiveness may be limited by algorithm choice and available entropy
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* during the boot.
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*
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* XXXRW: And that we don't randomize it yet!
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*
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* This is the default Microsoft RSS specification key which is also
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* the Chelsio T5 firmware default key.
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*/
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static uint8_t rss_key[RSS_KEYSIZE] = {
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0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x0e, 0xc2,
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0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0,
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0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4,
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0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c,
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0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa,
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};
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/*
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* RSS hash->CPU table, which maps hashed packet headers to particular CPUs.
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* Drivers may supplement this table with a separate CPU<->queue table when
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* programming devices.
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*/
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struct rss_table_entry {
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uint8_t rte_cpu; /* CPU affinity of bucket. */
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};
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static struct rss_table_entry rss_table[RSS_TABLE_MAXLEN];
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static void
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rss_init(__unused void *arg)
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{
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u_int i;
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u_int cpuid;
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/*
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* Validate tunables, coerce to sensible values.
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*/
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switch (rss_hashalgo) {
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case RSS_HASH_TOEPLITZ:
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case RSS_HASH_NAIVE:
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break;
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default:
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RSS_DEBUG("invalid RSS hashalgo %u, coercing to %u\n",
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rss_hashalgo, RSS_HASH_TOEPLITZ);
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rss_hashalgo = RSS_HASH_TOEPLITZ;
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}
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/*
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* Count available CPUs.
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*
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* XXXRW: Note incorrect assumptions regarding contiguity of this set
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* elsewhere.
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*/
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rss_ncpus = 0;
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for (i = 0; i <= mp_maxid; i++) {
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if (CPU_ABSENT(i))
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continue;
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rss_ncpus++;
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}
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if (rss_ncpus > RSS_MAXCPUS)
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rss_ncpus = RSS_MAXCPUS;
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/*
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* Tune RSS table entries to be no less than 2x the number of CPUs
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* -- unless we're running uniprocessor, in which case there's not
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* much point in having buckets to rearrange for load-balancing!
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*/
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if (rss_ncpus > 1) {
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if (rss_bits == 0)
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rss_bits = fls(rss_ncpus - 1) + 1;
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/*
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* Microsoft limits RSS table entries to 128, so apply that
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* limit to both auto-detected CPU counts and user-configured
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* ones.
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*/
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if (rss_bits == 0 || rss_bits > RSS_MAXBITS) {
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RSS_DEBUG("RSS bits %u not valid, coercing to %u\n",
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rss_bits, RSS_MAXBITS);
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rss_bits = RSS_MAXBITS;
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}
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/*
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* Figure out how many buckets to use; warn if less than the
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* number of configured CPUs, although this is not a fatal
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* problem.
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*/
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rss_buckets = (1 << rss_bits);
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if (rss_buckets < rss_ncpus)
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RSS_DEBUG("WARNING: rss_buckets (%u) less than "
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"rss_ncpus (%u)\n", rss_buckets, rss_ncpus);
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rss_mask = rss_buckets - 1;
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} else {
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rss_bits = 0;
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rss_buckets = 1;
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rss_mask = 0;
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}
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/*
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* Set up initial CPU assignments: round-robin by default.
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*/
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cpuid = CPU_FIRST();
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for (i = 0; i < rss_buckets; i++) {
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rss_table[i].rte_cpu = cpuid;
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cpuid = CPU_NEXT(cpuid);
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}
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/*
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* Randomize rrs_key.
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*
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* XXXRW: Not yet. If nothing else, will require an rss_isbadkey()
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* loop to check for "bad" RSS keys.
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*/
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}
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SYSINIT(rss_init, SI_SUB_SOFTINTR, SI_ORDER_SECOND, rss_init, NULL);
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static uint32_t
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rss_naive_hash(u_int keylen, const uint8_t *key, u_int datalen,
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const uint8_t *data)
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{
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uint32_t v;
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u_int i;
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v = 0;
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for (i = 0; i < keylen; i++)
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v += key[i];
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for (i = 0; i < datalen; i++)
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v += data[i];
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return (v);
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}
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uint32_t
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rss_hash(u_int datalen, const uint8_t *data)
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{
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switch (rss_hashalgo) {
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case RSS_HASH_TOEPLITZ:
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return (toeplitz_hash(sizeof(rss_key), rss_key, datalen,
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data));
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case RSS_HASH_NAIVE:
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return (rss_naive_hash(sizeof(rss_key), rss_key, datalen,
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data));
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default:
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panic("%s: unsupported/unknown hashalgo %d", __func__,
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rss_hashalgo);
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}
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}
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/*
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* Query the number of RSS bits in use.
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*/
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u_int
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rss_getbits(void)
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{
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return (rss_bits);
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}
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/*
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* Query the RSS bucket associated with an RSS hash.
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*/
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u_int
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rss_getbucket(u_int hash)
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{
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return (hash & rss_mask);
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}
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/*
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* Query the RSS layer bucket associated with the given
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* entry in the RSS hash space.
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*
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* The RSS indirection table is 0 .. rss_buckets-1,
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* covering the low 'rss_bits' of the total 128 slot
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* RSS indirection table. So just mask off rss_bits and
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* return that.
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*
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* NIC drivers can then iterate over the 128 slot RSS
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* indirection table and fetch which RSS bucket to
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* map it to. This will typically be a CPU queue
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*/
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u_int
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rss_get_indirection_to_bucket(u_int index)
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{
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return (index & rss_mask);
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}
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/*
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* Query the RSS CPU associated with an RSS bucket.
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*/
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u_int
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rss_getcpu(u_int bucket)
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{
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return (rss_table[bucket].rte_cpu);
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}
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/*
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* netisr CPU affinity lookup given just the hash and hashtype.
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*/
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u_int
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rss_hash2cpuid(uint32_t hash_val, uint32_t hash_type)
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{
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switch (hash_type) {
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case M_HASHTYPE_RSS_IPV4:
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case M_HASHTYPE_RSS_TCP_IPV4:
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case M_HASHTYPE_RSS_UDP_IPV4:
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case M_HASHTYPE_RSS_IPV6:
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case M_HASHTYPE_RSS_TCP_IPV6:
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case M_HASHTYPE_RSS_UDP_IPV6:
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return (rss_getcpu(rss_getbucket(hash_val)));
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default:
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return (NETISR_CPUID_NONE);
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}
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}
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/*
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* Query the RSS bucket associated with the given hash value and
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* type.
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*/
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int
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rss_hash2bucket(uint32_t hash_val, uint32_t hash_type, uint32_t *bucket_id)
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{
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switch (hash_type) {
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case M_HASHTYPE_RSS_IPV4:
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case M_HASHTYPE_RSS_TCP_IPV4:
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case M_HASHTYPE_RSS_UDP_IPV4:
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case M_HASHTYPE_RSS_IPV6:
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case M_HASHTYPE_RSS_TCP_IPV6:
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case M_HASHTYPE_RSS_UDP_IPV6:
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*bucket_id = rss_getbucket(hash_val);
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return (0);
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default:
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return (-1);
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}
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}
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/*
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* netisr CPU affinity lookup routine for use by protocols.
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*/
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struct mbuf *
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rss_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid)
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{
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M_ASSERTPKTHDR(m);
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*cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m));
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return (m);
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}
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int
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rss_m2bucket(struct mbuf *m, uint32_t *bucket_id)
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{
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M_ASSERTPKTHDR(m);
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return(rss_hash2bucket(m->m_pkthdr.flowid, M_HASHTYPE_GET(m),
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bucket_id));
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}
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/*
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* Query the RSS hash algorithm.
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*/
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u_int
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rss_gethashalgo(void)
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{
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return (rss_hashalgo);
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}
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/*
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* Query the current RSS key; likely to be used by device drivers when
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* configuring hardware RSS. Caller must pass an array of size RSS_KEYSIZE.
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*
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* XXXRW: Perhaps we should do the accept-a-length-and-truncate thing?
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*/
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void
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rss_getkey(uint8_t *key)
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{
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bcopy(rss_key, key, sizeof(rss_key));
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}
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/*
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* Query the number of buckets; this may be used by both network device
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* drivers, which will need to populate hardware shadows of the software
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* indirection table, and the network stack itself (such as when deciding how
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* many connection groups to allocate).
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*/
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u_int
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rss_getnumbuckets(void)
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{
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return (rss_buckets);
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}
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/*
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* Query the number of CPUs in use by RSS; may be useful to device drivers
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* trying to figure out how to map a larger number of CPUs into a smaller
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* number of receive queues.
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*/
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u_int
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rss_getnumcpus(void)
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{
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return (rss_ncpus);
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}
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/*
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* Return the supported RSS hash configuration.
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*
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* NICs should query this to determine what to configure in their redirection
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* matching table.
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*/
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inline u_int
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rss_gethashconfig(void)
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{
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/* Return 4-tuple for TCP; 2-tuple for others */
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/*
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* UDP may fragment more often than TCP and thus we'll end up with
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* NICs returning 2-tuple fragments.
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* udp_init() and udplite_init() both currently initialise things
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* as 2-tuple.
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* So for now disable UDP 4-tuple hashing until all of the other
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* pieces are in place.
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*/
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return (
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RSS_HASHTYPE_RSS_IPV4
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| RSS_HASHTYPE_RSS_TCP_IPV4
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| RSS_HASHTYPE_RSS_IPV6
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| RSS_HASHTYPE_RSS_TCP_IPV6
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| RSS_HASHTYPE_RSS_IPV6_EX
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| RSS_HASHTYPE_RSS_TCP_IPV6_EX
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#if 0
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| RSS_HASHTYPE_RSS_UDP_IPV4
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| RSS_HASHTYPE_RSS_UDP_IPV4_EX
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| RSS_HASHTYPE_RSS_UDP_IPV6
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| RSS_HASHTYPE_RSS_UDP_IPV6_EX
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#endif
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);
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}
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/*
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* XXXRW: Confirm that sysctl -a won't dump this keying material, don't want
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* it appearing in debugging output unnecessarily.
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*/
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static int
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sysctl_rss_key(SYSCTL_HANDLER_ARGS)
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{
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uint8_t temp_rss_key[RSS_KEYSIZE];
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int error;
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error = priv_check(req->td, PRIV_NETINET_HASHKEY);
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if (error)
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return (error);
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bcopy(rss_key, temp_rss_key, sizeof(temp_rss_key));
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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, NULL, 0,
|
|
sysctl_rss_bucket_mapping, "", "RSS bucket -> CPU mapping");
|