FreeBSD/Linux Kernel Cross Reference
sys/dev/cxgbe/t4_l2t.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2012 Chelsio Communications, Inc.
      * All rights reserved.
      *
      * 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_inet.h"
    #include "opt_inet6.h"
    
    #include <sys/param.h>
    #include <sys/eventhandler.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/bus.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/rwlock.h>
    #include <sys/socket.h>
    #include <sys/sbuf.h>
    #include <netinet/in.h>
    
    #include "common/common.h"
    #include "common/t4_msg.h"
    #include "t4_l2t.h"
    
    /*
     * Module locking notes:  There is a RW lock protecting the L2 table as a
     * whole plus a spinlock per L2T entry.  Entry lookups and allocations happen
     * under the protection of the table lock, individual entry changes happen
     * while holding that entry's spinlock.  The table lock nests outside the
     * entry locks.  Allocations of new entries take the table lock as writers so
     * no other lookups can happen while allocating new entries.  Entry updates
     * take the table lock as readers so multiple entries can be updated in
     * parallel.  An L2T entry can be dropped by decrementing its reference count
     * and therefore can happen in parallel with entry allocation but no entry
     * can change state or increment its ref count during allocation as both of
     * these perform lookups.
     *
     * Note: We do not take references to ifnets in this module because both
     * the TOE and the sockets already hold references to the interfaces and the
     * lifetime of an L2T entry is fully contained in the lifetime of the TOE.
     */
    
    /*
     * Allocate a free L2T entry.  Must be called with l2t_data.lock held.
     */
    struct l2t_entry *
    t4_alloc_l2e(struct l2t_data *d)
    {
            struct l2t_entry *end, *e, **p;
    
            rw_assert(&d->lock, RA_WLOCKED);
    
            if (!atomic_load_acq_int(&d->nfree))
                    return (NULL);
    
            /* there's definitely a free entry */
            for (e = d->rover, end = &d->l2tab[d->l2t_size]; e != end; ++e)
                    if (atomic_load_acq_int(&e->refcnt) == 0)
                            goto found;
    
            for (e = d->l2tab; atomic_load_acq_int(&e->refcnt); ++e)
                    continue;
    found:
            d->rover = e + 1;
            atomic_subtract_int(&d->nfree, 1);
    
            /*
             * 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);
   }
   
   static struct l2t_entry *
   find_or_alloc_l2e(struct l2t_data *d, uint16_t vlan, uint8_t port, uint8_t *dmac)
   {
           struct l2t_entry *end, *e, **p;
           struct l2t_entry *first_free = NULL;
   
           for (e = &d->l2tab[0], end = &d->l2tab[d->l2t_size]; e != end; ++e) {
                   if (atomic_load_acq_int(&e->refcnt) == 0) {
                           if (!first_free)
                                   first_free = e;
                   } else if (e->state == L2T_STATE_SWITCHING &&
                       memcmp(e->dmac, dmac, ETHER_ADDR_LEN) == 0 &&
                       e->vlan == vlan && e->lport == port)
                           return (e);     /* Found existing entry that matches. */
           }
   
           if (first_free == NULL)
                   return (NULL);  /* No match and no room for a new entry. */
   
           /*
            * The entry we found may be an inactive entry that is
            * presently in the hash table.  We need to remove it.
            */
           e = first_free;
           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);
   }
   
   static void
   mk_write_l2e(struct adapter *sc, struct l2t_entry *e, int sync, int reply,
       void *dst)
   {
           struct cpl_l2t_write_req *req;
           int idx;
   
           req = dst;
           idx = e->idx + sc->vres.l2t.start;
           INIT_TP_WR(req, 0);
           OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_L2T_WRITE_REQ, idx |
               V_SYNC_WR(sync) | V_TID_QID(e->iqid)));
           req->params = htons(V_L2T_W_PORT(e->lport) | V_L2T_W_NOREPLY(!reply));
           req->l2t_idx = htons(idx);
           req->vlan = htons(e->vlan);
           memcpy(req->dst_mac, e->dmac, sizeof(req->dst_mac));
   }
   
   /*
    * Write an L2T entry.  Must be called with the entry locked.
    * The write may be synchronous or asynchronous.
    */
   int
   t4_write_l2e(struct l2t_entry *e, int sync)
   {
           struct sge_wrq *wrq;
           struct adapter *sc;
           struct wrq_cookie cookie;
           struct cpl_l2t_write_req *req;
   
           mtx_assert(&e->lock, MA_OWNED);
           MPASS(e->wrq != NULL);
   
           wrq = e->wrq;
           sc = wrq->adapter;
   
           req = start_wrq_wr(wrq, howmany(sizeof(*req), 16), &cookie);
           if (req == NULL)
                   return (ENOMEM);
   
           mk_write_l2e(sc, e, sync, sync, req);
   
           commit_wrq_wr(wrq, req, &cookie);
   
           if (sync && e->state != L2T_STATE_SWITCHING)
                   e->state = L2T_STATE_SYNC_WRITE;
   
           return (0);
   }
   
   /*
    * Allocate an L2T entry for use by a TLS connection.  These entries are
    * associated with a specific VLAN and destination MAC that never changes.
    * However, multiple TLS connections might share a single entry.
    *
    * If a new L2T entry is allocated, a work request to initialize it is
    * written to 'txq' and 'ndesc' will be set to 1.  Otherwise, 'ndesc'
    * will be set to 0.
    *
    * To avoid races, separate L2T entries are reserved for individual
    * queues since the L2T entry update is written to a txq just prior to
    * TLS work requests that will depend on it being written.
    */
   struct l2t_entry *
   t4_l2t_alloc_tls(struct adapter *sc, struct sge_txq *txq, void *dst,
       int *ndesc, uint16_t vlan, uint8_t port, uint8_t *eth_addr)
   {
           struct l2t_data *d;
           struct l2t_entry *e;
           int i;
   
           TXQ_LOCK_ASSERT_OWNED(txq);
   
           d = sc->l2t;
           *ndesc = 0;
   
           rw_rlock(&d->lock);
   
           /* First, try to find an existing entry. */
           for (i = 0; i < d->l2t_size; i++) {
                   e = &d->l2tab[i];
                   if (e->state != L2T_STATE_TLS)
                           continue;
                   if (e->vlan == vlan && e->lport == port &&
                       e->wrq == (struct sge_wrq *)txq &&
                       memcmp(e->dmac, eth_addr, ETHER_ADDR_LEN) == 0) {
                           if (atomic_fetchadd_int(&e->refcnt, 1) == 0) {
                                   /*
                                    * This entry wasn't held but is still
                                    * valid, so decrement nfree.
                                    */
                                   atomic_subtract_int(&d->nfree, 1);
                           }
                           KASSERT(e->refcnt > 0,
                               ("%s: refcount overflow", __func__));
                           rw_runlock(&d->lock);
                           return (e);
                   }
           }
   
           /*
            * Don't bother rechecking if the upgrade fails since the txq is
            * already locked.
            */
           if (!rw_try_upgrade(&d->lock)) {
                   rw_runlock(&d->lock);
                   rw_wlock(&d->lock);
           }
   
           /* Match not found, allocate a new entry. */
           e = t4_alloc_l2e(d);
           if (e == NULL) {
                   rw_wunlock(&d->lock);
                   return (e);
           }
   
           /* Initialize the entry. */
           e->state = L2T_STATE_TLS;
           e->vlan = vlan;
           e->lport = port;
           e->iqid = sc->sge.fwq.abs_id;
           e->wrq = (struct sge_wrq *)txq;
           memcpy(e->dmac, eth_addr, ETHER_ADDR_LEN);
           atomic_store_rel_int(&e->refcnt, 1);
           rw_wunlock(&d->lock);
   
           /* Write out the work request. */
           *ndesc = howmany(sizeof(struct cpl_l2t_write_req), EQ_ESIZE);
           MPASS(*ndesc == 1);
           mk_write_l2e(sc, e, 1, 0, dst);
   
           return (e);
   }
   
   /*
    * Allocate an L2T entry for use by a switching rule.  Such need to be
    * explicitly freed and while busy they are not on any hash chain, so normal
    * address resolution updates do not see them.
    */
   struct l2t_entry *
   t4_l2t_alloc_switching(struct adapter *sc, uint16_t vlan, uint8_t port,
       uint8_t *eth_addr)
   {
           struct l2t_data *d = sc->l2t;
           struct l2t_entry *e;
           int rc;
   
           rw_wlock(&d->lock);
           e = find_or_alloc_l2e(d, vlan, port, eth_addr);
           if (e) {
                   if (atomic_load_acq_int(&e->refcnt) == 0) {
                           mtx_lock(&e->lock);    /* avoid race with t4_l2t_free */
                           e->wrq = &sc->sge.ctrlq[0];
                           e->iqid = sc->sge.fwq.abs_id;
                           e->state = L2T_STATE_SWITCHING;
                           e->vlan = vlan;
                           e->lport = port;
                           memcpy(e->dmac, eth_addr, ETHER_ADDR_LEN);
                           atomic_store_rel_int(&e->refcnt, 1);
                           atomic_subtract_int(&d->nfree, 1);
                           rc = t4_write_l2e(e, 0);
                           mtx_unlock(&e->lock);
                           if (rc != 0)
                                   e = NULL;
                   } else {
                           MPASS(e->vlan == vlan);
                           MPASS(e->lport == port);
                           atomic_add_int(&e->refcnt, 1);
                   }
           }
           rw_wunlock(&d->lock);
           return (e);
   }
   
   int
   t4_init_l2t(struct adapter *sc, int flags)
   {
           int i, l2t_size;
           struct l2t_data *d;
   
           l2t_size = sc->vres.l2t.size;
           if (l2t_size < 2)       /* At least 1 bucket for IP and 1 for IPv6 */
                   return (EINVAL);
   
           d = malloc(sizeof(*d) + l2t_size * sizeof (struct l2t_entry), M_CXGBE,
               M_ZERO | flags);
           if (!d)
                   return (ENOMEM);
   
           d->l2t_size = l2t_size;
           d->rover = d->l2tab;
           atomic_store_rel_int(&d->nfree, l2t_size);
           rw_init(&d->lock, "L2T");
   
           for (i = 0; i < l2t_size; i++) {
                   struct l2t_entry *e = &d->l2tab[i];
   
                   e->idx = i;
                   e->state = L2T_STATE_UNUSED;
                   mtx_init(&e->lock, "L2T_E", NULL, MTX_DEF);
                   STAILQ_INIT(&e->wr_list);
                   atomic_store_rel_int(&e->refcnt, 0);
           }
   
           sc->l2t = d;
   
           return (0);
   }
   
   int
   t4_free_l2t(struct l2t_data *d)
   {
           int i;
   
           for (i = 0; i < d->l2t_size; i++)
                   mtx_destroy(&d->l2tab[i].lock);
           rw_destroy(&d->lock);
           free(d, M_CXGBE);
   
           return (0);
   }
   
   int
   do_l2t_write_rpl(struct sge_iq *iq, const struct rss_header *rss,
       struct mbuf *m)
   {
           const struct cpl_l2t_write_rpl *rpl = (const void *)(rss + 1);
           unsigned int tid = GET_TID(rpl);
           unsigned int idx = tid % L2T_SIZE;
   
           if (__predict_false(rpl->status != CPL_ERR_NONE)) {
                   log(LOG_ERR,
                       "Unexpected L2T_WRITE_RPL (%u) for entry at hw_idx %u\n",
                       rpl->status, idx);
                   return (EINVAL);
           }
   
           return (0);
   }
   
   static inline unsigned int
   vlan_prio(const struct l2t_entry *e)
   {
           return e->vlan >> 13;
   }
   
   static char
   l2e_state(const struct l2t_entry *e)
   {
           switch (e->state) {
           case L2T_STATE_VALID: return 'V';  /* valid, fast-path entry */
           case L2T_STATE_STALE: return 'S';  /* needs revalidation, but usable */
           case L2T_STATE_SYNC_WRITE: return 'W';
           case L2T_STATE_RESOLVING: return STAILQ_EMPTY(&e->wr_list) ? 'R' : 'A';
           case L2T_STATE_SWITCHING: return 'X';
           case L2T_STATE_TLS: return 'T';
           default: return 'U';
           }
   }
   
   int
   sysctl_l2t(SYSCTL_HANDLER_ARGS)
   {
           struct adapter *sc = arg1;
           struct l2t_data *l2t = sc->l2t;
           struct l2t_entry *e;
           struct sbuf *sb;
           int rc, i, header = 0;
           char ip[INET6_ADDRSTRLEN];
   
           if (l2t == NULL)
                   return (ENXIO);
   
           rc = sysctl_wire_old_buffer(req, 0);
           if (rc != 0)
                   return (rc);
   
           sb = sbuf_new_for_sysctl(NULL, NULL, 4096, req);
           if (sb == NULL)
                   return (ENOMEM);
   
           e = &l2t->l2tab[0];
           for (i = 0; i < l2t->l2t_size; i++, e++) {
                   mtx_lock(&e->lock);
                   if (e->state == L2T_STATE_UNUSED)
                           goto skip;
   
                   if (header == 0) {
                           sbuf_printf(sb, " Idx IP address      "
                               "Ethernet address  VLAN/P LP State Users Port");
                           header = 1;
                   }
                   if (e->state >= L2T_STATE_SWITCHING)
                           ip[0] = 0;
                   else {
                           inet_ntop(e->ipv6 ? AF_INET6 : AF_INET, &e->addr[0],
                               &ip[0], sizeof(ip));
                   }
   
                   /*
                    * XXX: IPv6 addresses may not align properly in the output.
                    */
                   sbuf_printf(sb, "\n%4u %-15s %02x:%02x:%02x:%02x:%02x:%02x %4d"
                              " %u %2u   %c   %5u %s",
                              e->idx, ip, e->dmac[0], e->dmac[1], e->dmac[2],
                              e->dmac[3], e->dmac[4], e->dmac[5],
                              e->vlan & 0xfff, vlan_prio(e), e->lport,
                              l2e_state(e), atomic_load_acq_int(&e->refcnt),
                              e->ifp ? e->ifp->if_xname : "-");
   skip:
                   mtx_unlock(&e->lock);
           }
   
           rc = sbuf_finish(sb);
           sbuf_delete(sb);
   
           return (rc);
   }

Cache object: 89528737dd9cd325f1a89dcc5b40a9f7