LXR linux/drivers/net/ethernet/chelsio/cxgb3/l2t.h

   1/*
   2 * Copyright (c) 2003-2008 Chelsio, Inc. All rights reserved.
   3 *
   4 * This software is available to you under a choice of one of two
   5 * licenses.  You may choose to be licensed under the terms of the GNU
   6 * General Public License (GPL) Version 2, available from the file
   7 * COPYING in the main directory of this source tree, or the
   8 * OpenIB.org BSD license below:
   9 *
  10 *     Redistribution and use in source and binary forms, with or
  11 *     without modification, are permitted provided that the following
  12 *     conditions are met:
  13 *
  14 *      - Redistributions of source code must retain the above
  15 *        copyright notice, this list of conditions and the following
  16 *        disclaimer.
  17 *
  18 *      - Redistributions in binary form must reproduce the above
  19 *        copyright notice, this list of conditions and the following
  20 *        disclaimer in the documentation and/or other materials
  21 *        provided with the distribution.
  22 *
  23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30 * SOFTWARE.
  31 */
  32#ifndef _CHELSIO_L2T_H
  33#define _CHELSIO_L2T_H
  34
  35#include <linux/spinlock.h>
  36#include "t3cdev.h"
  37#include <linux/atomic.h>
  38
  39enum {
  40        L2T_STATE_VALID,        /* entry is up to date */
  41        L2T_STATE_STALE,        /* entry may be used but needs revalidation */
  42        L2T_STATE_RESOLVING,    /* entry needs address resolution */
  43        L2T_STATE_UNUSED        /* entry not in use */
  44};
  45
  46struct neighbour;
  47struct sk_buff;
  48
  49/*
  50 * Each L2T entry plays multiple roles.  First of all, it keeps state for the
  51 * corresponding entry of the HW L2 table and maintains a queue of offload
  52 * packets awaiting address resolution.  Second, it is a node of a hash table
  53 * chain, where the nodes of the chain are linked together through their next
  54 * pointer.  Finally, each node is a bucket of a hash table, pointing to the
  55 * first element in its chain through its first pointer.
  56 */
  57struct l2t_entry {
  58        u16 state;              /* entry state */
  59        u16 idx;                /* entry index */
  60        u32 addr;               /* dest IP address */
  61        int ifindex;            /* neighbor's net_device's ifindex */
  62        u16 smt_idx;            /* SMT index */
  63        u16 vlan;               /* VLAN TCI (id: bits 0-11, prio: 13-15 */
  64        struct neighbour *neigh;        /* associated neighbour */
  65        struct l2t_entry *first;        /* start of hash chain */
  66        struct l2t_entry *next; /* next l2t_entry on chain */
  67        struct sk_buff_head arpq;       /* queue of packets awaiting resolution */
  68        spinlock_t lock;
  69        atomic_t refcnt;        /* entry reference count */
  70        u8 dmac[6];             /* neighbour's MAC address */
  71};
  72
  73struct l2t_data {
  74        unsigned int nentries;  /* number of entries */
  75        struct l2t_entry *rover;        /* starting point for next allocation */
  76        atomic_t nfree;         /* number of free entries */
  77        rwlock_t lock;
  78        struct l2t_entry l2tab[0];
  79        struct rcu_head rcu_head;       /* to handle rcu cleanup */
  80};
  81
  82typedef void (*arp_failure_handler_func)(struct t3cdev * dev,
  83                                         struct sk_buff * skb);
  84
  85/*
  86 * Callback stored in an skb to handle address resolution failure.
  87 */
  88struct l2t_skb_cb {
  89        arp_failure_handler_func arp_failure_handler;
  90};
  91
  92#define L2T_SKB_CB(skb) ((struct l2t_skb_cb *)(skb)->cb)
  93
  94static inline void set_arp_failure_handler(struct sk_buff *skb,
  95                                           arp_failure_handler_func hnd)
  96{
  97        L2T_SKB_CB(skb)->arp_failure_handler = hnd;
  98}
  99
 100/*
 101 * Getting to the L2 data from an offload device.
 102 */
 103#define L2DATA(cdev) (rcu_dereference((cdev)->l2opt))
 104
 105#define W_TCB_L2T_IX    0
 106#define S_TCB_L2T_IX    7
 107#define M_TCB_L2T_IX    0x7ffULL
 108#define V_TCB_L2T_IX(x) ((x) << S_TCB_L2T_IX)
 109
 110void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e);
 111void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh);
 112struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct dst_entry *dst,
 113                             struct net_device *dev, const void *daddr);
 114int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb,
 115                     struct l2t_entry *e);
 116void t3_l2t_send_event(struct t3cdev *dev, struct l2t_entry *e);
 117struct l2t_data *t3_init_l2t(unsigned int l2t_capacity);
 118
 119int cxgb3_ofld_send(struct t3cdev *dev, struct sk_buff *skb);
 120
 121static inline int l2t_send(struct t3cdev *dev, struct sk_buff *skb,
 122                           struct l2t_entry *e)
 123{
 124        if (likely(e->state == L2T_STATE_VALID))
 125                return cxgb3_ofld_send(dev, skb);
 126        return t3_l2t_send_slow(dev, skb, e);
 127}
 128
 129static inline void l2t_release(struct t3cdev *t, struct l2t_entry *e)
 130{
 131        struct l2t_data *d;
 132
 133        rcu_read_lock();
 134        d = L2DATA(t);
 135
 136        if (atomic_dec_and_test(&e->refcnt) && d)
 137                t3_l2e_free(d, e);
 138
 139        rcu_read_unlock();
 140}
 141
 142static inline void l2t_hold(struct l2t_data *d, struct l2t_entry *e)
 143{
 144        if (d && atomic_add_return(1, &e->refcnt) == 1) /* 0 -> 1 transition */
 145                atomic_dec(&d->nfree);
 146}
 147
 148#endif
 149