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kernel/linux-rt-4.4.41/drivers/net/ethernet/chelsio/cxgb3/l2t.h 4.88 KB
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  /*
   * 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.
   */
  #ifndef _CHELSIO_L2T_H
  #define _CHELSIO_L2T_H
  
  #include <linux/spinlock.h>
  #include "t3cdev.h"
  #include <linux/atomic.h>
  
  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_UNUSED	/* entry not in use */
  };
  
  struct neighbour;
  struct sk_buff;
  
  /*
   * Each L2T entry plays multiple roles.  First of all, it keeps state for the
   * corresponding entry of the HW L2 table and maintains a queue of offload
   * packets awaiting address resolution.  Second, it is a node of a hash table
   * chain, where the nodes of the chain are linked together through their next
   * pointer.  Finally, each node is a bucket of a hash table, pointing to the
   * first element in its chain through its first pointer.
   */
  struct l2t_entry {
  	u16 state;		/* entry state */
  	u16 idx;		/* entry index */
  	u32 addr;		/* dest IP address */
  	int ifindex;		/* neighbor's net_device's ifindex */
  	u16 smt_idx;		/* SMT index */
  	u16 vlan;		/* VLAN TCI (id: bits 0-11, prio: 13-15 */
  	struct neighbour *neigh;	/* associated neighbour */
  	struct l2t_entry *first;	/* start of hash chain */
  	struct l2t_entry *next;	/* next l2t_entry on chain */
  	struct sk_buff_head arpq;	/* queue of packets awaiting resolution */
  	spinlock_t lock;
  	atomic_t refcnt;	/* entry reference count */
  	u8 dmac[6];		/* neighbour's MAC address */
  };
  
  struct l2t_data {
  	unsigned int nentries;	/* number of entries */
  	struct l2t_entry *rover;	/* starting point for next allocation */
  	atomic_t nfree;		/* number of free entries */
  	rwlock_t lock;
  	struct l2t_entry l2tab[0];
  	struct rcu_head rcu_head;	/* to handle rcu cleanup */
  };
  
  typedef void (*arp_failure_handler_func)(struct t3cdev * dev,
  					 struct sk_buff * skb);
  
  /*
   * Callback stored in an skb to handle address resolution failure.
   */
  struct l2t_skb_cb {
  	arp_failure_handler_func arp_failure_handler;
  };
  
  #define L2T_SKB_CB(skb) ((struct l2t_skb_cb *)(skb)->cb)
  
  static inline void set_arp_failure_handler(struct sk_buff *skb,
  					   arp_failure_handler_func hnd)
  {
  	L2T_SKB_CB(skb)->arp_failure_handler = hnd;
  }
  
  /*
   * Getting to the L2 data from an offload device.
   */
  #define L2DATA(cdev) (rcu_dereference((cdev)->l2opt))
  
  #define W_TCB_L2T_IX    0
  #define S_TCB_L2T_IX    7
  #define M_TCB_L2T_IX    0x7ffULL
  #define V_TCB_L2T_IX(x) ((x) << S_TCB_L2T_IX)
  
  void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e);
  void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh);
  struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct dst_entry *dst,
  			     struct net_device *dev, const void *daddr);
  int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb,
  		     struct l2t_entry *e);
  void t3_l2t_send_event(struct t3cdev *dev, struct l2t_entry *e);
  struct l2t_data *t3_init_l2t(unsigned int l2t_capacity);
  void t3_free_l2t(struct l2t_data *d);
  
  int cxgb3_ofld_send(struct t3cdev *dev, struct sk_buff *skb);
  
  static inline int l2t_send(struct t3cdev *dev, struct sk_buff *skb,
  			   struct l2t_entry *e)
  {
  	if (likely(e->state == L2T_STATE_VALID))
  		return cxgb3_ofld_send(dev, skb);
  	return t3_l2t_send_slow(dev, skb, e);
  }
  
  static inline void l2t_release(struct t3cdev *t, struct l2t_entry *e)
  {
  	struct l2t_data *d;
  
  	rcu_read_lock();
  	d = L2DATA(t);
  
  	if (atomic_dec_and_test(&e->refcnt) && d)
  		t3_l2e_free(d, e);
  
  	rcu_read_unlock();
  }
  
  static inline void l2t_hold(struct l2t_data *d, struct l2t_entry *e)
  {
  	if (d && atomic_add_return(1, &e->refcnt) == 1)	/* 0 -> 1 transition */
  		atomic_dec(&d->nfree);
  }
  
  #endif