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 rcu_head rcu_head;	/* to handle rcu cleanup */
 79	struct l2t_entry l2tab[] __counted_by(nentries);
 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