cxgbe/t4nex/t4_l2t.c

/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source. A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * This file is part of the Chelsio T4 support code.
 *
 * Copyright (C) 2010-2013 Chelsio Communications.  All rights reserved.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the LICENSE file included in this
 * release for licensing terms and conditions.
 */

#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/sunndi.h>
#include <sys/atomic.h>
#include <sys/dlpi.h>
#include <sys/pattr.h>
#include <sys/strsubr.h>
#include <sys/stream.h>
#include <sys/strsun.h>
#include <sys/ethernet.h>
#include <inet/ip.h>
#include <inet/ipclassifier.h>
#include <inet/tcp.h>

#include "common/common.h"
#include "common/t4_msg.h"
#include "common/t4_regs.h"
#include "common/t4_regs_values.h"
#include "t4_l2t.h"

/* identifies sync vs async L2T_WRITE_REQs */
#define S_SYNC_WR   12
#define V_SYNC_WR(x)    ((x) << S_SYNC_WR)
#define F_SYNC_WR   V_SYNC_WR(1)
#define VLAN_NONE   0xfff

/*
 * jhash.h: Jenkins hash support.
 *
 * Copyright (C) 1996 Bob Jenkins (bob_jenkins@burtleburtle.net)
 *
 * http://burtleburtle.net/bob/hash/
 *
 * These are the credits from Bob's sources:
 *
 * lookup2.c, by Bob Jenkins, December 1996, Public Domain.
 * hash(), hash2(), hash3, and mix() are externally useful functions.
 * Routines to test the hash are included if SELF_TEST is defined.
 * You can use this free for any purpose.  It has no warranty.
 */

/* NOTE: Arguments are modified. */
#define __jhash_mix(a, b, c) \
{ \
    a -= b; a -= c; a ^= (c>>13); \
    b -= c; b -= a; b ^= (a<<8); \
    c -= a; c -= b; c ^= (b>>13); \
    a -= b; a -= c; a ^= (c>>12);  \
    b -= c; b -= a; b ^= (a<<16); \
    c -= a; c -= b; c ^= (b>>5); \
    a -= b; a -= c; a ^= (c>>3);  \
    b -= c; b -= a; b ^= (a<<10); \
    c -= a; c -= b; c ^= (b>>15); \
}

/* The golden ration: an arbitrary value */
#define JHASH_GOLDEN_RATIO  0x9e3779b9

/*
 * A special ultra-optimized versions that knows they are hashing exactly
 * 3, 2 or 1 word(s).
 *
 * NOTE: In partilar the "c += length; __jhash_mix(a,b,c);" normally
 *   done at the end is not done here.
 */
static inline u32
jhash_3words(u32 a, u32 b, u32 c, u32 initval)
{
    a += JHASH_GOLDEN_RATIO;
    b += JHASH_GOLDEN_RATIO;
    c += initval;

    __jhash_mix(a, b, c);

    return (c);
}

static inline u32
jhash_2words(u32 a, u32 b, u32 initval)
{
    return (jhash_3words(a, b, 0, initval));
}

#ifndef container_of
#define container_of(p, s, f) ((s *)(((uint8_t *)(p)) - offsetof(s, f)))
#endif

#if defined(__GNUC__)
#define likely(x)   __builtin_expect((x), 1)
#define unlikely(x) __builtin_expect((x), 0)
#else
#define likely(x)   (x)
#define unlikely(x) (x)
#endif /* defined(__GNUC__) */

enum {
    L2T_STATE_VALID,    /* entry is up to date */
    L2T_STATE_STALE,    /* entry may be used but needs revalidation */
    L2T_STATE_RESOLVING,    /* entry needs address resolution */
    L2T_STATE_SYNC_WRITE,   /* synchronous write of entry underway */

    /* when state is one of the below the entry is not hashed */
    L2T_STATE_SWITCHING,    /* entry is being used by a switching filter */
    L2T_STATE_UNUSED    /* entry not in use */
};

struct l2t_data {
    krwlock_t lock;
    volatile uint_t nfree;   /* number of free entries */
    struct l2t_entry *rover; /* starting point for next allocation */
    struct l2t_entry l2tab[L2T_SIZE];
};

#define VLAN_NONE   0xfff
#define SA(x)       ((struct sockaddr *)(x))
#define SIN(x)      ((struct sockaddr_in *)(x))
#define SINADDR(x)  (SIN(x)->sin_addr.s_addr)
#define atomic_read(x) atomic_add_int_nv(x, 0)
/*
 * Allocate a free L2T entry.
 * Must be called with l2t_data.lockatomic_load_acq_int held.
 */
static struct l2t_entry *
alloc_l2e(struct l2t_data *d)
{
    struct l2t_entry *end, *e, **p;

    ASSERT(rw_write_held(&d->lock));

    if (!atomic_read(&d->nfree))
        return (NULL);

    /* there's definitely a free entry */
    for (e = d->rover, end = &d->l2tab[L2T_SIZE]; e != end; ++e)
        if (atomic_read(&e->refcnt) == 0)
            goto found;

    for (e = d->l2tab; atomic_read(&e->refcnt); ++e)
        /* */;
found:
    d->rover = e + 1;
    atomic_dec_uint(&d->nfree);

    /*
     * The entry we found may be an inactive entry that is
     * presently in the hash table.  We need to remove it.
     */
    if (e->state < L2T_STATE_SWITCHING) {
        for (p = &d->l2tab[e->hash].first; *p; p = &(*p)->next) {
            if (*p == e) {
                *p = e->next;
                e->next = NULL;
                break;
            }
        }
    }

    e->state = L2T_STATE_UNUSED;
    return (e);
}

/*
 * Write an L2T entry.  Must be called with the entry locked.
 * The write may be synchronous or asynchronous.
 */
static int
write_l2e(adapter_t *sc, struct l2t_entry *e, int sync)
{
    mblk_t *m;
    struct cpl_l2t_write_req *req;

    ASSERT(MUTEX_HELD(&e->lock));

    if ((m = allocb(sizeof (*req), BPRI_HI)) == NULL)
        return (ENOMEM);

    /* LINTED: E_BAD_PTR_CAST_ALIGN */
    req = (struct cpl_l2t_write_req *)m->b_wptr;

    /* LINTED: E_CONSTANT_CONDITION */
    INIT_TP_WR(req, 0);
    OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_L2T_WRITE_REQ, e->idx |
        V_SYNC_WR(sync) | V_TID_QID(sc->sge.fwq.abs_id)));
    req->params = htons(V_L2T_W_PORT(e->lport) | V_L2T_W_NOREPLY(!sync));
    req->l2t_idx = htons(e->idx);
    req->vlan = htons(e->vlan);
    (void) memcpy(req->dst_mac, e->dmac, sizeof (req->dst_mac));

    m->b_wptr += sizeof (*req);

    (void) t4_mgmt_tx(sc, m);

    if (sync && e->state != L2T_STATE_SWITCHING)
        e->state = L2T_STATE_SYNC_WRITE;

    return (0);
}

struct l2t_data *
t4_init_l2t(struct adapter *sc)
{
    int i;
    struct l2t_data *d;

    d = kmem_zalloc(sizeof (*d), KM_SLEEP);

    d->rover = d->l2tab;
    (void) atomic_swap_uint(&d->nfree, L2T_SIZE);
    rw_init(&d->lock, NULL, RW_DRIVER, NULL);

    for (i = 0; i < L2T_SIZE; i++) {
        /* LINTED: E_ASSIGN_NARROW_CONV */
        d->l2tab[i].idx = i;
        d->l2tab[i].state = L2T_STATE_UNUSED;
        mutex_init(&d->l2tab[i].lock, NULL, MUTEX_DRIVER, NULL);
        (void) atomic_swap_uint(&d->l2tab[i].refcnt, 0);
    }

    (void) t4_register_cpl_handler(sc, CPL_L2T_WRITE_RPL, do_l2t_write_rpl);

    return (d);
}

int
t4_free_l2t(struct l2t_data *d)
{
    int i;

    for (i = 0; i < L2T_SIZE; i++)
        mutex_destroy(&d->l2tab[i].lock);
    rw_destroy(&d->lock);
    kmem_free(d, sizeof (*d));

    return (0);
}

#ifndef TCP_OFFLOAD_DISABLE
static inline void
l2t_hold(struct l2t_data *d, struct l2t_entry *e)
{
    if (atomic_inc_uint_nv(&e->refcnt) == 1)  /* 0 -> 1 transition */
        atomic_dec_uint(&d->nfree);
}

/*
 * To avoid having to check address families we do not allow v4 and v6
 * neighbors to be on the same hash chain.  We keep v4 entries in the first
 * half of available hash buckets and v6 in the second.
 */
enum {
    L2T_SZ_HALF = L2T_SIZE / 2,
    L2T_HASH_MASK = L2T_SZ_HALF - 1
};

static inline unsigned int
arp_hash(const uint32_t *key, int ifindex)
{
    return (jhash_2words(*key, ifindex, 0) & L2T_HASH_MASK);
}

static inline unsigned int
ipv6_hash(const uint32_t *key, int ifindex)
{
    uint32_t xor = key[0] ^ key[1] ^ key[2] ^ key[3];

    return (L2T_SZ_HALF + (jhash_2words(xor, ifindex, 0) & L2T_HASH_MASK));
}

static inline unsigned int
addr_hash(const uint32_t *addr, int addr_len, int ifindex)
{
    return (addr_len == 4 ? arp_hash(addr, ifindex) :
        ipv6_hash(addr, ifindex));
}

/*
 * Checks if an L2T entry is for the given IP/IPv6 address.  It does not check
 * whether the L2T entry and the address are of the same address family.
 * Callers ensure an address is only checked against L2T entries of the same
 * family, something made trivial by the separation of IP and IPv6 hash chains
 * mentioned above.  Returns 0 if there's a match,
 */
static inline int
addreq(const struct l2t_entry *e, const uint32_t *addr)
{
    if (e->v6 != 0)
        return ((e->addr[0] ^ addr[0]) | (e->addr[1] ^ addr[1]) |
            (e->addr[2] ^ addr[2]) | (e->addr[3] ^ addr[3]));
    return (e->addr[0] ^ addr[0]);
}

/*
 * Add a packet to an L2T entry's queue of packets awaiting resolution.
 * Must be called with the entry's lock held.
 */
static inline void
arpq_enqueue(struct l2t_entry *e, mblk_t *m)
{
    ASSERT(MUTEX_HELD(&e->lock));

    ASSERT(m->b_next == NULL);
    if (e->arpq_head != NULL)
        e->arpq_tail->b_next = m;
    else
        e->arpq_head = m;
    e->arpq_tail = m;
}

static inline void
send_pending(struct adapter *sc, struct l2t_entry *e)
{
    mblk_t *m, *next;

    ASSERT(MUTEX_HELD(&e->lock));

    for (m = e->arpq_head; m; m = next) {
        next = m->b_next;
        m->b_next = NULL;
        (void) t4_wrq_tx(sc, MBUF_EQ(m), m);
    }
    e->arpq_head = e->arpq_tail = NULL;
}

int
t4_l2t_send(struct adapter *sc, mblk_t *m, struct l2t_entry *e)
{
    sin_t *sin;
    ip2mac_t ip2m;

    if (e->v6 != 0)
        ASSERT(0);
again:
    switch (e->state) {
    case L2T_STATE_STALE:   /* entry is stale, kick off revalidation */

    /* Fall through */
    case L2T_STATE_VALID:   /* fast-path, send the packet on */
        (void) t4_wrq_tx(sc, MBUF_EQ(m), m);
        return (0);

    case L2T_STATE_RESOLVING:
    case L2T_STATE_SYNC_WRITE:
        mutex_enter(&e->lock);
        if (e->state != L2T_STATE_SYNC_WRITE &&
            e->state != L2T_STATE_RESOLVING) {
            /* state changed by the time we got here */
            mutex_exit(&e->lock);
            goto again;
        }
        arpq_enqueue(e, m);
        mutex_exit(&e->lock);

        bzero(&ip2m, sizeof (ip2m));
        sin = (sin_t *)&ip2m.ip2mac_pa;
        sin->sin_family = AF_INET;
        sin->sin_addr.s_addr = e->in_addr;
        ip2m.ip2mac_ifindex = e->ifindex;

        if (e->state == L2T_STATE_RESOLVING) {
            (void) ip2mac(IP2MAC_RESOLVE, &ip2m, t4_l2t_update, e,
                0);
            if (ip2m.ip2mac_err == EINPROGRESS)
                ASSERT(0);
            else if (ip2m.ip2mac_err == 0)
                t4_l2t_update(&ip2m, e);
            else
                ASSERT(0);
        }
    }

    return (0);
}

/*
 * Called when an L2T entry has no more users.  The entry is left in the hash
 * table since it is likely to be reused but we also bump nfree to indicate
 * that the entry can be reallocated for a different neighbor.  We also drop
 * the existing neighbor reference in case the neighbor is going away and is
 * waiting on our reference.
 *
 * Because entries can be reallocated to other neighbors once their ref count
 * drops to 0 we need to take the entry's lock to avoid races with a new
 * incarnation.
 */
static void
t4_l2e_free(struct l2t_entry *e)
{
    struct l2t_data *d;

    mutex_enter(&e->lock);
    /* LINTED: E_NOP_IF_STMT */
    if (atomic_read(&e->refcnt) == 0) {  /* hasn't been recycled */
        /*
         * Don't need to worry about the arpq, an L2T entry can't be
         * released if any packets are waiting for resolution as we
         * need to be able to communicate with the device to close a
         * connection.
         */
    }
    mutex_exit(&e->lock);

    d = container_of(e, struct l2t_data, l2tab[e->idx]);
    atomic_inc_uint(&d->nfree);

}

void
t4_l2t_release(struct l2t_entry *e)
{
    if (atomic_dec_uint_nv(&e->refcnt) == 0)
        t4_l2e_free(e);
}

/* ARGSUSED */
int
do_l2t_write_rpl(struct sge_iq *iq, const struct rss_header *rss, mblk_t *m)
{
    struct adapter *sc = iq->adapter;
    const struct cpl_l2t_write_rpl *rpl = (const void *)(rss + 1);
    unsigned int tid = GET_TID(rpl);
    unsigned int idx = tid & (L2T_SIZE - 1);

    if (likely(rpl->status != CPL_ERR_NONE)) {
        cxgb_printf(sc->dip, CE_WARN,
            "Unexpected L2T_WRITE_RPL status %u for entry %u",
            rpl->status, idx);
        return (-EINVAL);
    }

    if (tid & F_SYNC_WR) {
        struct l2t_entry *e = &sc->l2t->l2tab[idx];

        mutex_enter(&e->lock);
        if (e->state != L2T_STATE_SWITCHING) {
            send_pending(sc, e);
            e->state = L2T_STATE_VALID;
        }
        mutex_exit(&e->lock);
    }

    return (0);
}

/*
 * The TOE wants an L2 table entry that it can use to reach the next hop over
 * the specified port.  Produce such an entry - create one if needed.
 *
 * Note that the ifnet could be a pseudo-device like if_vlan, if_lagg, etc. on
 * top of the real cxgbe interface.
 */
struct l2t_entry *
t4_l2t_get(struct port_info *pi, conn_t *connp)
{
    struct l2t_entry *e;
    struct l2t_data *d = pi->adapter->l2t;
    int addr_len;
    uint32_t *addr;
    int hash;
    int index = \
        connp->conn_ixa->ixa_ire->ire_ill->ill_phyint->phyint_ifindex;
    unsigned int smt_idx = pi->port_id;
    addr = (uint32_t *)&connp->conn_faddr_v4;
    addr_len  = sizeof (connp->conn_faddr_v4);

    hash = addr_hash(addr, addr_len, index);

    rw_enter(&d->lock, RW_WRITER);
    for (e = d->l2tab[hash].first; e; e = e->next) {
        if (!addreq(e, addr) && e->smt_idx == smt_idx) {
            l2t_hold(d, e);
            goto done;
        }
    }

    /* Need to allocate a new entry */
    e = alloc_l2e(d);
    if (e != NULL) {
        mutex_enter(&e->lock);  /* avoid race with t4_l2t_free */
        e->state = L2T_STATE_RESOLVING;
        (void) memcpy(e->addr, addr, addr_len);
        e->in_addr = connp->conn_faddr_v4;
        e->ifindex = index;
        /* LINTED: E_ASSIGN_NARROW_CONV */
        e->smt_idx = smt_idx;
        /* LINTED: E_ASSIGN_NARROW_CONV */
        e->hash = hash;
        e->lport = pi->lport;
        e->arpq_head = e->arpq_tail = NULL;
        e->v6 = (addr_len == 16);
        e->sc = pi->adapter;
        (void) atomic_swap_uint(&e->refcnt, 1);
        e->vlan = VLAN_NONE;
        e->next = d->l2tab[hash].first;
        d->l2tab[hash].first = e;
        mutex_exit(&e->lock);
    } else {
        ASSERT(0);
    }

done:
    rw_exit(&d->lock);
    return (e);
}

/*
 * Called when the host's neighbor layer makes a change to some entry that is
 * loaded into the HW L2 table.
 */
void
t4_l2t_update(ip2mac_t *ip2macp, void *arg)
{
    struct l2t_entry *e = (struct l2t_entry *)arg;
    struct adapter *sc = e->sc;
    uchar_t *cp;

    if (ip2macp->ip2mac_err != 0) {
        ASSERT(0); /* Don't know what to do. Needs to be investigated */
    }

    mutex_enter(&e->lock);
    if (atomic_read(&e->refcnt) != 0)
        goto found;
    e->state = L2T_STATE_STALE;
    mutex_exit(&e->lock);

    /* The TOE has no interest in this LLE */
    return;

found:
    if (atomic_read(&e->refcnt) != 0) {

        /* Entry is referenced by at least 1 offloaded connection. */

        cp = (uchar_t *)LLADDR(&ip2macp->ip2mac_ha);
        bcopy(cp, e->dmac, 6);
        (void) write_l2e(sc, e, 1);
        e->state = L2T_STATE_VALID;

    }
    mutex_exit(&e->lock);
}
#endif