--- /dev/null
+/*
+ * Copyright (c) 2003-2008 Chelsio, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - 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.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/if.h>
+#include <linux/if_vlan.h>
+#include <linux/jhash.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <net/neighbour.h>
+#include "common.h"
+#include "t3cdev.h"
+#include "cxgb3_defs.h"
+#include "l2t.h"
+#include "t3_cpl.h"
+#include "firmware_exports.h"
+
+#define VLAN_NONE 0xfff
+
+/*
+ * 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.
+ */
+
+static inline unsigned int vlan_prio(const struct l2t_entry *e)
+{
+ return e->vlan >> 13;
+}
+
+static inline unsigned int arp_hash(u32 key, int ifindex,
+ const struct l2t_data *d)
+{
+ return jhash_2words(key, ifindex, 0) & (d->nentries - 1);
+}
+
+static inline void neigh_replace(struct l2t_entry *e, struct neighbour *n)
+{
+ neigh_hold(n);
+ if (e->neigh)
+ neigh_release(e->neigh);
+ e->neigh = n;
+}
+
+/*
+ * Set up an L2T entry and send any packets waiting in the arp queue. The
+ * supplied skb is used for the CPL_L2T_WRITE_REQ. Must be called with the
+ * entry locked.
+ */
+static int setup_l2e_send_pending(struct t3cdev *dev, struct sk_buff *skb,
+ struct l2t_entry *e)
+{
+ struct cpl_l2t_write_req *req;
+ struct sk_buff *tmp;
+
+ if (!skb) {
+ skb = alloc_skb(sizeof(*req), GFP_ATOMIC);
+ if (!skb)
+ return -ENOMEM;
+ }
+
+ req = (struct cpl_l2t_write_req *)__skb_put(skb, sizeof(*req));
+ req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_FORWARD));
+ OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_L2T_WRITE_REQ, e->idx));
+ req->params = htonl(V_L2T_W_IDX(e->idx) | V_L2T_W_IFF(e->smt_idx) |
+ V_L2T_W_VLAN(e->vlan & VLAN_VID_MASK) |
+ V_L2T_W_PRIO(vlan_prio(e)));
+ memcpy(e->dmac, e->neigh->ha, sizeof(e->dmac));
+ memcpy(req->dst_mac, e->dmac, sizeof(req->dst_mac));
+ skb->priority = CPL_PRIORITY_CONTROL;
+ cxgb3_ofld_send(dev, skb);
+
+ skb_queue_walk_safe(&e->arpq, skb, tmp) {
+ __skb_unlink(skb, &e->arpq);
+ cxgb3_ofld_send(dev, skb);
+ }
+ e->state = L2T_STATE_VALID;
+
+ return 0;
+}
+
+/*
+ * Add a packet to the 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, struct sk_buff *skb)
+{
+ __skb_queue_tail(&e->arpq, skb);
+}
+
+int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb,
+ struct l2t_entry *e)
+{
+again:
+ switch (e->state) {
+ case L2T_STATE_STALE: /* entry is stale, kick off revalidation */
+ neigh_event_send(e->neigh, NULL);
+ spin_lock_bh(&e->lock);
+ if (e->state == L2T_STATE_STALE)
+ e->state = L2T_STATE_VALID;
+ spin_unlock_bh(&e->lock);
+ case L2T_STATE_VALID: /* fast-path, send the packet on */
+ return cxgb3_ofld_send(dev, skb);
+ case L2T_STATE_RESOLVING:
+ spin_lock_bh(&e->lock);
+ if (e->state != L2T_STATE_RESOLVING) {
+ /* ARP already completed */
+ spin_unlock_bh(&e->lock);
+ goto again;
+ }
+ arpq_enqueue(e, skb);
+ spin_unlock_bh(&e->lock);
+
+ /*
+ * Only the first packet added to the arpq should kick off
+ * resolution. However, because the alloc_skb below can fail,
+ * we allow each packet added to the arpq to retry resolution
+ * as a way of recovering from transient memory exhaustion.
+ * A better way would be to use a work request to retry L2T
+ * entries when there's no memory.
+ */
+ if (!neigh_event_send(e->neigh, NULL)) {
+ skb = alloc_skb(sizeof(struct cpl_l2t_write_req),
+ GFP_ATOMIC);
+ if (!skb)
+ break;
+
+ spin_lock_bh(&e->lock);
+ if (!skb_queue_empty(&e->arpq))
+ setup_l2e_send_pending(dev, skb, e);
+ else /* we lost the race */
+ __kfree_skb(skb);
+ spin_unlock_bh(&e->lock);
+ }
+ }
+ return 0;
+}
+
+EXPORT_SYMBOL(t3_l2t_send_slow);
+
+void t3_l2t_send_event(struct t3cdev *dev, struct l2t_entry *e)
+{
+again:
+ switch (e->state) {
+ case L2T_STATE_STALE: /* entry is stale, kick off revalidation */
+ neigh_event_send(e->neigh, NULL);
+ spin_lock_bh(&e->lock);
+ if (e->state == L2T_STATE_STALE) {
+ e->state = L2T_STATE_VALID;
+ }
+ spin_unlock_bh(&e->lock);
+ return;
+ case L2T_STATE_VALID: /* fast-path, send the packet on */
+ return;
+ case L2T_STATE_RESOLVING:
+ spin_lock_bh(&e->lock);
+ if (e->state != L2T_STATE_RESOLVING) {
+ /* ARP already completed */
+ spin_unlock_bh(&e->lock);
+ goto again;
+ }
+ spin_unlock_bh(&e->lock);
+
+ /*
+ * Only the first packet added to the arpq should kick off
+ * resolution. However, because the alloc_skb below can fail,
+ * we allow each packet added to the arpq to retry resolution
+ * as a way of recovering from transient memory exhaustion.
+ * A better way would be to use a work request to retry L2T
+ * entries when there's no memory.
+ */
+ neigh_event_send(e->neigh, NULL);
+ }
+}
+
+EXPORT_SYMBOL(t3_l2t_send_event);
+
+/*
+ * Allocate a free L2T entry. Must be called with l2t_data.lock held.
+ */
+static struct l2t_entry *alloc_l2e(struct l2t_data *d)
+{
+ struct l2t_entry *end, *e, **p;
+
+ if (!atomic_read(&d->nfree))
+ return NULL;
+
+ /* there's definitely a free entry */
+ for (e = d->rover, end = &d->l2tab[d->nentries]; e != end; ++e)
+ if (atomic_read(&e->refcnt) == 0)
+ goto found;
+
+ for (e = &d->l2tab[1]; atomic_read(&e->refcnt); ++e) ;
+found:
+ d->rover = e + 1;
+ atomic_dec(&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_UNUSED) {
+ int hash = arp_hash(e->addr, e->ifindex, d);
+
+ for (p = &d->l2tab[hash].first; *p; p = &(*p)->next)
+ if (*p == e) {
+ *p = e->next;
+ break;
+ }
+ e->state = L2T_STATE_UNUSED;
+ }
+ return e;
+}
+
+/*
+ * 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.
+ */
+void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e)
+{
+ spin_lock_bh(&e->lock);
+ if (atomic_read(&e->refcnt) == 0) { /* hasn't been recycled */
+ if (e->neigh) {
+ neigh_release(e->neigh);
+ e->neigh = NULL;
+ }
+ }
+ spin_unlock_bh(&e->lock);
+ atomic_inc(&d->nfree);
+}
+
+EXPORT_SYMBOL(t3_l2e_free);
+
+/*
+ * Update an L2T entry that was previously used for the same next hop as neigh.
+ * Must be called with softirqs disabled.
+ */
+static inline void reuse_entry(struct l2t_entry *e, struct neighbour *neigh)
+{
+ unsigned int nud_state;
+
+ spin_lock(&e->lock); /* avoid race with t3_l2t_free */
+
+ if (neigh != e->neigh)
+ neigh_replace(e, neigh);
+ nud_state = neigh->nud_state;
+ if (memcmp(e->dmac, neigh->ha, sizeof(e->dmac)) ||
+ !(nud_state & NUD_VALID))
+ e->state = L2T_STATE_RESOLVING;
+ else if (nud_state & NUD_CONNECTED)
+ e->state = L2T_STATE_VALID;
+ else
+ e->state = L2T_STATE_STALE;
+ spin_unlock(&e->lock);
+}
+
+struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct dst_entry *dst,
+ struct net_device *dev, const void *daddr)
+{
+ struct l2t_entry *e = NULL;
+ struct neighbour *neigh;
+ struct port_info *p;
+ struct l2t_data *d;
+ int hash;
+ u32 addr;
+ int ifidx;
+ int smt_idx;
+
+ rcu_read_lock();
+ neigh = dst_neigh_lookup(dst, daddr);
+ if (!neigh)
+ goto done_rcu;
+
+ addr = *(u32 *) neigh->primary_key;
+ ifidx = neigh->dev->ifindex;
+
+ if (!dev)
+ dev = neigh->dev;
+ p = netdev_priv(dev);
+ smt_idx = p->port_id;
+
+ d = L2DATA(cdev);
+ if (!d)
+ goto done_rcu;
+
+ hash = arp_hash(addr, ifidx, d);
+
+ write_lock_bh(&d->lock);
+ for (e = d->l2tab[hash].first; e; e = e->next)
+ if (e->addr == addr && e->ifindex == ifidx &&
+ e->smt_idx == smt_idx) {
+ l2t_hold(d, e);
+ if (atomic_read(&e->refcnt) == 1)
+ reuse_entry(e, neigh);
+ goto done_unlock;
+ }
+
+ /* Need to allocate a new entry */
+ e = alloc_l2e(d);
+ if (e) {
+ spin_lock(&e->lock); /* avoid race with t3_l2t_free */
+ e->next = d->l2tab[hash].first;
+ d->l2tab[hash].first = e;
+ e->state = L2T_STATE_RESOLVING;
+ e->addr = addr;
+ e->ifindex = ifidx;
+ e->smt_idx = smt_idx;
+ atomic_set(&e->refcnt, 1);
+ neigh_replace(e, neigh);
+ if (neigh->dev->priv_flags & IFF_802_1Q_VLAN)
+ e->vlan = vlan_dev_vlan_id(neigh->dev);
+ else
+ e->vlan = VLAN_NONE;
+ spin_unlock(&e->lock);
+ }
+done_unlock:
+ write_unlock_bh(&d->lock);
+done_rcu:
+ if (neigh)
+ neigh_release(neigh);
+ rcu_read_unlock();
+ return e;
+}
+
+EXPORT_SYMBOL(t3_l2t_get);
+
+/*
+ * Called when address resolution fails for an L2T entry to handle packets
+ * on the arpq head. If a packet specifies a failure handler it is invoked,
+ * otherwise the packets is sent to the offload device.
+ *
+ * XXX: maybe we should abandon the latter behavior and just require a failure
+ * handler.
+ */
+static void handle_failed_resolution(struct t3cdev *dev, struct sk_buff_head *arpq)
+{
+ struct sk_buff *skb, *tmp;
+
+ skb_queue_walk_safe(arpq, skb, tmp) {
+ struct l2t_skb_cb *cb = L2T_SKB_CB(skb);
+
+ __skb_unlink(skb, arpq);
+ if (cb->arp_failure_handler)
+ cb->arp_failure_handler(dev, skb);
+ else
+ cxgb3_ofld_send(dev, skb);
+ }
+}
+
+/*
+ * Called when the host's ARP layer makes a change to some entry that is
+ * loaded into the HW L2 table.
+ */
+void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh)
+{
+ struct sk_buff_head arpq;
+ struct l2t_entry *e;
+ struct l2t_data *d = L2DATA(dev);
+ u32 addr = *(u32 *) neigh->primary_key;
+ int ifidx = neigh->dev->ifindex;
+ int hash = arp_hash(addr, ifidx, d);
+
+ read_lock_bh(&d->lock);
+ for (e = d->l2tab[hash].first; e; e = e->next)
+ if (e->addr == addr && e->ifindex == ifidx) {
+ spin_lock(&e->lock);
+ goto found;
+ }
+ read_unlock_bh(&d->lock);
+ return;
+
+found:
+ __skb_queue_head_init(&arpq);
+
+ read_unlock(&d->lock);
+ if (atomic_read(&e->refcnt)) {
+ if (neigh != e->neigh)
+ neigh_replace(e, neigh);
+
+ if (e->state == L2T_STATE_RESOLVING) {
+ if (neigh->nud_state & NUD_FAILED) {
+ skb_queue_splice_init(&e->arpq, &arpq);
+ } else if (neigh->nud_state & (NUD_CONNECTED|NUD_STALE))
+ setup_l2e_send_pending(dev, NULL, e);
+ } else {
+ e->state = neigh->nud_state & NUD_CONNECTED ?
+ L2T_STATE_VALID : L2T_STATE_STALE;
+ if (!ether_addr_equal(e->dmac, neigh->ha))
+ setup_l2e_send_pending(dev, NULL, e);
+ }
+ }
+ spin_unlock_bh(&e->lock);
+
+ if (!skb_queue_empty(&arpq))
+ handle_failed_resolution(dev, &arpq);
+}
+
+struct l2t_data *t3_init_l2t(unsigned int l2t_capacity)
+{
+ struct l2t_data *d;
+ int i, size = sizeof(*d) + l2t_capacity * sizeof(struct l2t_entry);
+
+ d = cxgb_alloc_mem(size);
+ if (!d)
+ return NULL;
+
+ d->nentries = l2t_capacity;
+ d->rover = &d->l2tab[1]; /* entry 0 is not used */
+ atomic_set(&d->nfree, l2t_capacity - 1);
+ rwlock_init(&d->lock);
+
+ for (i = 0; i < l2t_capacity; ++i) {
+ d->l2tab[i].idx = i;
+ d->l2tab[i].state = L2T_STATE_UNUSED;
+ __skb_queue_head_init(&d->l2tab[i].arpq);
+ spin_lock_init(&d->l2tab[i].lock);
+ atomic_set(&d->l2tab[i].refcnt, 0);
+ }
+ return d;
+}
+
+void t3_free_l2t(struct l2t_data *d)
+{
+ cxgb_free_mem(d);
+}
+
Code Review / kvmfornfv.git / blobdiff