[mirror_ubuntu-zesty-kernel.git] / net / core / flow.c

/* flow.c: Generic flow cache.
 *
 * Copyright (C) 2003 Alexey N. Kuznetsov (kuznet@ms2.inr.ac.ru)
 * Copyright (C) 2003 David S. Miller (davem@redhat.com)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/jhash.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <linux/percpu.h>
#include <linux/bitops.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/mutex.h>
#include <net/flow.h>
#include <linux/atomic.h>
#include <linux/security.h>
#include <net/net_namespace.h>

struct flow_cache_entry {
	union {
		struct hlist_node	hlist;
		struct list_head	gc_list;
	} u;
	struct net			*net;
	u16				family;
	u8				dir;
	u32				genid;
	struct flowi			key;
	struct flow_cache_object	*object;
};

struct flow_flush_info {
	struct flow_cache		*cache;
	atomic_t			cpuleft;
	struct completion		completion;
};

static struct kmem_cache *flow_cachep __read_mostly;

#define flow_cache_hash_size(cache)	(1 << (cache)->hash_shift)
#define FLOW_HASH_RND_PERIOD		(10 * 60 * HZ)

static void flow_cache_new_hashrnd(unsigned long arg)
{
	struct flow_cache *fc = (void *) arg;
	int i;

	for_each_possible_cpu(i)
		per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;

	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
	add_timer(&fc->rnd_timer);
}

static int flow_entry_valid(struct flow_cache_entry *fle,
				struct netns_xfrm *xfrm)
{
	if (atomic_read(&xfrm->flow_cache_genid) != fle->genid)
		return 0;
	if (fle->object && !fle->object->ops->check(fle->object))
		return 0;
	return 1;
}

static void flow_entry_kill(struct flow_cache_entry *fle,
				struct netns_xfrm *xfrm)
{
	if (fle->object)
		fle->object->ops->delete(fle->object);
	kmem_cache_free(flow_cachep, fle);
}

static void flow_cache_gc_task(struct work_struct *work)
{
	struct list_head gc_list;
	struct flow_cache_entry *fce, *n;
	struct netns_xfrm *xfrm = container_of(work, struct netns_xfrm,
						flow_cache_gc_work);

	INIT_LIST_HEAD(&gc_list);
	spin_lock_bh(&xfrm->flow_cache_gc_lock);
	list_splice_tail_init(&xfrm->flow_cache_gc_list, &gc_list);
	spin_unlock_bh(&xfrm->flow_cache_gc_lock);

	list_for_each_entry_safe(fce, n, &gc_list, u.gc_list) {
		flow_entry_kill(fce, xfrm);
		atomic_dec(&xfrm->flow_cache_gc_count);
	}
}

static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp,
				     int deleted, struct list_head *gc_list,
				     struct netns_xfrm *xfrm)
{
	if (deleted) {
		atomic_add(deleted, &xfrm->flow_cache_gc_count);
		fcp->hash_count -= deleted;
		spin_lock_bh(&xfrm->flow_cache_gc_lock);
		list_splice_tail(gc_list, &xfrm->flow_cache_gc_list);
		spin_unlock_bh(&xfrm->flow_cache_gc_lock);
		schedule_work(&xfrm->flow_cache_gc_work);
	}
}

static void __flow_cache_shrink(struct flow_cache *fc,
				struct flow_cache_percpu *fcp,
				int shrink_to)
{
	struct flow_cache_entry *fle;
	struct hlist_node *tmp;
	LIST_HEAD(gc_list);
	int i, deleted = 0;
	struct netns_xfrm *xfrm = container_of(fc, struct netns_xfrm,
						flow_cache_global);

	for (i = 0; i < flow_cache_hash_size(fc); i++) {
		int saved = 0;

		hlist_for_each_entry_safe(fle, tmp,
					  &fcp->hash_table[i], u.hlist) {
			if (saved < shrink_to &&
			    flow_entry_valid(fle, xfrm)) {
				saved++;
			} else {
				deleted++;
				hlist_del(&fle->u.hlist);
				list_add_tail(&fle->u.gc_list, &gc_list);
			}
		}
	}

	flow_cache_queue_garbage(fcp, deleted, &gc_list, xfrm);
}

static void flow_cache_shrink(struct flow_cache *fc,
			      struct flow_cache_percpu *fcp)
{
	int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);

	__flow_cache_shrink(fc, fcp, shrink_to);
}

static void flow_new_hash_rnd(struct flow_cache *fc,
			      struct flow_cache_percpu *fcp)
{
	get_random_bytes(&fcp->hash_rnd, sizeof(u32));
	fcp->hash_rnd_recalc = 0;
	__flow_cache_shrink(fc, fcp, 0);
}

static u32 flow_hash_code(struct flow_cache *fc,
			  struct flow_cache_percpu *fcp,
			  const struct flowi *key,
			  size_t keysize)
{
	const u32 *k = (const u32 *) key;
	const u32 length = keysize * sizeof(flow_compare_t) / sizeof(u32);

	return jhash2(k, length, fcp->hash_rnd)
		& (flow_cache_hash_size(fc) - 1);
}

/* I hear what you're saying, use memcmp.  But memcmp cannot make
 * important assumptions that we can here, such as alignment.
 */
static int flow_key_compare(const struct flowi *key1, const struct flowi *key2,
			    size_t keysize)
{
	const flow_compare_t *k1, *k1_lim, *k2;

	k1 = (const flow_compare_t *) key1;
	k1_lim = k1 + keysize;

	k2 = (const flow_compare_t *) key2;

	do {
		if (*k1++ != *k2++)
			return 1;
	} while (k1 < k1_lim);

	return 0;
}

struct flow_cache_object *
flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir,
		  flow_resolve_t resolver, void *ctx)
{
	struct flow_cache *fc = &net->xfrm.flow_cache_global;
	struct flow_cache_percpu *fcp;
	struct flow_cache_entry *fle, *tfle;
	struct flow_cache_object *flo;
	size_t keysize;
	unsigned int hash;

	local_bh_disable();
	fcp = this_cpu_ptr(fc->percpu);

	fle = NULL;
	flo = NULL;

	keysize = flow_key_size(family);
	if (!keysize)
		goto nocache;

	/* Packet really early in init?  Making flow_cache_init a
	 * pre-smp initcall would solve this.  --RR */
	if (!fcp->hash_table)
		goto nocache;

	if (fcp->hash_rnd_recalc)
		flow_new_hash_rnd(fc, fcp);

	hash = flow_hash_code(fc, fcp, key, keysize);
	hlist_for_each_entry(tfle, &fcp->hash_table[hash], u.hlist) {
		if (tfle->net == net &&
		    tfle->family == family &&
		    tfle->dir == dir &&
		    flow_key_compare(key, &tfle->key, keysize) == 0) {
			fle = tfle;
			break;
		}
	}

	if (unlikely(!fle)) {
		if (fcp->hash_count > fc->high_watermark)
			flow_cache_shrink(fc, fcp);

		if (atomic_read(&net->xfrm.flow_cache_gc_count) >
		    2 * num_online_cpus() * fc->high_watermark) {
			flo = ERR_PTR(-ENOBUFS);
			goto ret_object;
		}

		fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
		if (fle) {
			fle->net = net;
			fle->family = family;
			fle->dir = dir;
			memcpy(&fle->key, key, keysize * sizeof(flow_compare_t));
			fle->object = NULL;
			hlist_add_head(&fle->u.hlist, &fcp->hash_table[hash]);
			fcp->hash_count++;
		}
	} else if (likely(fle->genid == atomic_read(&net->xfrm.flow_cache_genid))) {
		flo = fle->object;
		if (!flo)
			goto ret_object;
		flo = flo->ops->get(flo);
		if (flo)
			goto ret_object;
	} else if (fle->object) {
	        flo = fle->object;
	        flo->ops->delete(flo);
	        fle->object = NULL;
	}

nocache:
	flo = NULL;
	if (fle) {
		flo = fle->object;
		fle->object = NULL;
	}
	flo = resolver(net, key, family, dir, flo, ctx);
	if (fle) {
		fle->genid = atomic_read(&net->xfrm.flow_cache_genid);
		if (!IS_ERR(flo))
			fle->object = flo;
		else
			fle->genid--;
	} else {
		if (!IS_ERR_OR_NULL(flo))
			flo->ops->delete(flo);
	}
ret_object:
	local_bh_enable();
	return flo;
}
EXPORT_SYMBOL(flow_cache_lookup);

static void flow_cache_flush_tasklet(unsigned long data)
{
	struct flow_flush_info *info = (void *)data;
	struct flow_cache *fc = info->cache;
	struct flow_cache_percpu *fcp;
	struct flow_cache_entry *fle;
	struct hlist_node *tmp;
	LIST_HEAD(gc_list);
	int i, deleted = 0;
	struct netns_xfrm *xfrm = container_of(fc, struct netns_xfrm,
						flow_cache_global);

	fcp = this_cpu_ptr(fc->percpu);
	for (i = 0; i < flow_cache_hash_size(fc); i++) {
		hlist_for_each_entry_safe(fle, tmp,
					  &fcp->hash_table[i], u.hlist) {
			if (flow_entry_valid(fle, xfrm))
				continue;

			deleted++;
			hlist_del(&fle->u.hlist);
			list_add_tail(&fle->u.gc_list, &gc_list);
		}
	}

	flow_cache_queue_garbage(fcp, deleted, &gc_list, xfrm);

	if (atomic_dec_and_test(&info->cpuleft))
		complete(&info->completion);
}

/*
 * Return whether a cpu needs flushing.  Conservatively, we assume
 * the presence of any entries means the core may require flushing,
 * since the flow_cache_ops.check() function may assume it's running
 * on the same core as the per-cpu cache component.
 */
static int flow_cache_percpu_empty(struct flow_cache *fc, int cpu)
{
	struct flow_cache_percpu *fcp;
	int i;

	fcp = per_cpu_ptr(fc->percpu, cpu);
	for (i = 0; i < flow_cache_hash_size(fc); i++)
		if (!hlist_empty(&fcp->hash_table[i]))
			return 0;
	return 1;
}

static void flow_cache_flush_per_cpu(void *data)
{
	struct flow_flush_info *info = data;
	struct tasklet_struct *tasklet;

	tasklet = &this_cpu_ptr(info->cache->percpu)->flush_tasklet;
	tasklet->data = (unsigned long)info;
	tasklet_schedule(tasklet);
}

void flow_cache_flush(struct net *net)
{
	struct flow_flush_info info;
	cpumask_var_t mask;
	int i, self;

	/* Track which cpus need flushing to avoid disturbing all cores. */
	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
		return;
	cpumask_clear(mask);

	/* Don't want cpus going down or up during this. */
	get_online_cpus();
	mutex_lock(&net->xfrm.flow_flush_sem);
	info.cache = &net->xfrm.flow_cache_global;
	for_each_online_cpu(i)
		if (!flow_cache_percpu_empty(info.cache, i))
			cpumask_set_cpu(i, mask);
	atomic_set(&info.cpuleft, cpumask_weight(mask));
	if (atomic_read(&info.cpuleft) == 0)
		goto done;

	init_completion(&info.completion);

	local_bh_disable();
	self = cpumask_test_and_clear_cpu(smp_processor_id(), mask);
	on_each_cpu_mask(mask, flow_cache_flush_per_cpu, &info, 0);
	if (self)
		flow_cache_flush_tasklet((unsigned long)&info);
	local_bh_enable();

	wait_for_completion(&info.completion);

done:
	mutex_unlock(&net->xfrm.flow_flush_sem);
	put_online_cpus();
	free_cpumask_var(mask);
}

static void flow_cache_flush_task(struct work_struct *work)
{
	struct netns_xfrm *xfrm = container_of(work, struct netns_xfrm,
						flow_cache_flush_work);
	struct net *net = container_of(xfrm, struct net, xfrm);

	flow_cache_flush(net);
}

void flow_cache_flush_deferred(struct net *net)
{
	schedule_work(&net->xfrm.flow_cache_flush_work);
}

static int flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
{
	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
	size_t sz = sizeof(struct hlist_head) * flow_cache_hash_size(fc);

	if (!fcp->hash_table) {
		fcp->hash_table = kzalloc_node(sz, GFP_KERNEL, cpu_to_node(cpu));
		if (!fcp->hash_table) {
			pr_err("NET: failed to allocate flow cache sz %zu\n", sz);
			return -ENOMEM;
		}
		fcp->hash_rnd_recalc = 1;
		fcp->hash_count = 0;
		tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
	}
	return 0;
}

static int flow_cache_cpu_up_prep(unsigned int cpu, struct hlist_node *node)
{
	struct flow_cache *fc = hlist_entry_safe(node, struct flow_cache, node);

	return flow_cache_cpu_prepare(fc, cpu);
}

static int flow_cache_cpu_dead(unsigned int cpu, struct hlist_node *node)
{
	struct flow_cache *fc = hlist_entry_safe(node, struct flow_cache, node);
	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);

	__flow_cache_shrink(fc, fcp, 0);
	return 0;
}

int flow_cache_init(struct net *net)
{
	int i;
	struct flow_cache *fc = &net->xfrm.flow_cache_global;

	if (!flow_cachep)
		flow_cachep = kmem_cache_create("flow_cache",
						sizeof(struct flow_cache_entry),
						0, SLAB_PANIC, NULL);
	spin_lock_init(&net->xfrm.flow_cache_gc_lock);
	INIT_LIST_HEAD(&net->xfrm.flow_cache_gc_list);
	INIT_WORK(&net->xfrm.flow_cache_gc_work, flow_cache_gc_task);
	INIT_WORK(&net->xfrm.flow_cache_flush_work, flow_cache_flush_task);
	mutex_init(&net->xfrm.flow_flush_sem);
	atomic_set(&net->xfrm.flow_cache_gc_count, 0);

	fc->hash_shift = 10;
	fc->low_watermark = 2 * flow_cache_hash_size(fc);
	fc->high_watermark = 4 * flow_cache_hash_size(fc);

	fc->percpu = alloc_percpu(struct flow_cache_percpu);
	if (!fc->percpu)
		return -ENOMEM;

	if (cpuhp_state_add_instance(CPUHP_NET_FLOW_PREPARE, &fc->node))
		goto err;

	setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
		    (unsigned long) fc);
	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
	add_timer(&fc->rnd_timer);

	return 0;

err:
	for_each_possible_cpu(i) {
		struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
		kfree(fcp->hash_table);
		fcp->hash_table = NULL;
	}

	free_percpu(fc->percpu);
	fc->percpu = NULL;

	return -ENOMEM;
}
EXPORT_SYMBOL(flow_cache_init);

void flow_cache_fini(struct net *net)
{
	int i;
	struct flow_cache *fc = &net->xfrm.flow_cache_global;

	del_timer_sync(&fc->rnd_timer);

	cpuhp_state_remove_instance_nocalls(CPUHP_NET_FLOW_PREPARE, &fc->node);

	for_each_possible_cpu(i) {
		struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
		kfree(fcp->hash_table);
		fcp->hash_table = NULL;
	}

	free_percpu(fc->percpu);
	fc->percpu = NULL;
}
EXPORT_SYMBOL(flow_cache_fini);

void __init flow_cache_hp_init(void)
{
	int ret;

	ret = cpuhp_setup_state_multi(CPUHP_NET_FLOW_PREPARE,
				      "net/flow:prepare",
				      flow_cache_cpu_up_prep,
				      flow_cache_cpu_dead);
	WARN_ON(ret < 0);
}
Commit	Line	Data
1da177e4 LT	1	/* flow.c: Generic flow cache.
	2	*
	3	* Copyright (C) 2003 Alexey N. Kuznetsov (kuznet@ms2.inr.ac.ru)
	4	* Copyright (C) 2003 David S. Miller (davem@redhat.com)
	5	*/
	6
	7	#include <linux/kernel.h>
	8	#include <linux/module.h>
	9	#include <linux/list.h>
	10	#include <linux/jhash.h>
	11	#include <linux/interrupt.h>
	12	#include <linux/mm.h>
	13	#include <linux/random.h>
	14	#include <linux/init.h>
	15	#include <linux/slab.h>
	16	#include <linux/smp.h>
	17	#include <linux/completion.h>
	18	#include <linux/percpu.h>
	19	#include <linux/bitops.h>
	20	#include <linux/notifier.h>
	21	#include <linux/cpu.h>
	22	#include <linux/cpumask.h>
4a3e2f71	23	#include <linux/mutex.h>
1da177e4	24	#include <net/flow.h>
60063497	25	#include <linux/atomic.h>
df71837d	26	#include <linux/security.h>
ca925cf1	27	#include <net/net_namespace.h>
1da177e4 LT	28
1da177e4 LT	29	struct flow_cache_entry {
8e479560 TT	30	union {
	31	struct hlist_node hlist;
	32	struct list_head gc_list;
	33	} u;
0542b69e	34	struct net *net;
fe1a5f03 TT	35	u16 family;
	36	u8 dir;
	37	u32 genid;
	38	struct flowi key;
	39	struct flow_cache_object *object;
1da177e4 LT	40	};
1da177e4 LT	41
1da177e4	42	struct flow_flush_info {
fe1a5f03	43	struct flow_cache *cache;
d7997fe1 TT	44	atomic_t cpuleft;
d7997fe1 TT	45	struct completion completion;
1da177e4	46	};
1da177e4	47
d32d9bb8 ED	48	static struct kmem_cache *flow_cachep __read_mostly;
d32d9bb8 ED	49
d7997fe1 TT	50	#define flow_cache_hash_size(cache) (1 << (cache)->hash_shift)
d7997fe1 TT	51	#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
1da177e4 LT	52
	53	static void flow_cache_new_hashrnd(unsigned long arg)
	54	{
d7997fe1	55	struct flow_cache fc = (void ) arg;
1da177e4 LT	56	int i;
1da177e4 LT	57
6f912042	58	for_each_possible_cpu(i)
d7997fe1	59	per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;
1da177e4	60
d7997fe1 TT	61	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
d7997fe1 TT	62	add_timer(&fc->rnd_timer);
1da177e4 LT	63	}
1da177e4 LT	64
ca925cf1 FD	65	static int flow_entry_valid(struct flow_cache_entry *fle,
ca925cf1 FD	66	struct netns_xfrm *xfrm)
fe1a5f03	67	{
ca925cf1	68	if (atomic_read(&xfrm->flow_cache_genid) != fle->genid)
fe1a5f03 TT	69	return 0;
	70	if (fle->object && !fle->object->ops->check(fle->object))
	71	return 0;
	72	return 1;
	73	}
	74
ca925cf1 FD	75	static void flow_entry_kill(struct flow_cache_entry *fle,
ca925cf1 FD	76	struct netns_xfrm *xfrm)
134b0fc5 JM	77	{
134b0fc5 JM	78	if (fle->object)
fe1a5f03	79	fle->object->ops->delete(fle->object);
d32d9bb8	80	kmem_cache_free(flow_cachep, fle);
8e479560 TT	81	}
	82
	83	static void flow_cache_gc_task(struct work_struct *work)
	84	{
	85	struct list_head gc_list;
	86	struct flow_cache_entry fce, n;
ca925cf1 FD	87	struct netns_xfrm *xfrm = container_of(work, struct netns_xfrm,
ca925cf1 FD	88	flow_cache_gc_work);
8e479560 TT	89
8e479560 TT	90	INIT_LIST_HEAD(&gc_list);
ca925cf1 FD	91	spin_lock_bh(&xfrm->flow_cache_gc_lock);
	92	list_splice_tail_init(&xfrm->flow_cache_gc_list, &gc_list);
	93	spin_unlock_bh(&xfrm->flow_cache_gc_lock);
8e479560	94
6ad3122a	95	list_for_each_entry_safe(fce, n, &gc_list, u.gc_list) {
ca925cf1	96	flow_entry_kill(fce, xfrm);
6ad3122a	97	atomic_dec(&xfrm->flow_cache_gc_count);
6ad3122a	98	}
8e479560	99	}
8e479560 TT	100
8e479560 TT	101	static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp,
ca925cf1 FD	102	int deleted, struct list_head *gc_list,
ca925cf1 FD	103	struct netns_xfrm *xfrm)
8e479560 TT	104	{
8e479560 TT	105	if (deleted) {
6ad3122a	106	atomic_add(deleted, &xfrm->flow_cache_gc_count);
8e479560	107	fcp->hash_count -= deleted;
ca925cf1 FD	108	spin_lock_bh(&xfrm->flow_cache_gc_lock);
	109	list_splice_tail(gc_list, &xfrm->flow_cache_gc_list);
	110	spin_unlock_bh(&xfrm->flow_cache_gc_lock);
	111	schedule_work(&xfrm->flow_cache_gc_work);
8e479560	112	}
134b0fc5 JM	113	}
134b0fc5 JM	114
d7997fe1 TT	115	static void __flow_cache_shrink(struct flow_cache *fc,
	116	struct flow_cache_percpu *fcp,
	117	int shrink_to)
1da177e4	118	{
8e479560	119	struct flow_cache_entry *fle;
b67bfe0d	120	struct hlist_node *tmp;
8e479560 TT	121	LIST_HEAD(gc_list);
8e479560 TT	122	int i, deleted = 0;
ca925cf1 FD	123	struct netns_xfrm *xfrm = container_of(fc, struct netns_xfrm,
ca925cf1 FD	124	flow_cache_global);
1da177e4	125
d7997fe1	126	for (i = 0; i < flow_cache_hash_size(fc); i++) {
fe1a5f03	127	int saved = 0;
1da177e4	128
b67bfe0d	129	hlist_for_each_entry_safe(fle, tmp,
8e479560	130	&fcp->hash_table[i], u.hlist) {
fe1a5f03	131	if (saved < shrink_to &&
ca925cf1	132	flow_entry_valid(fle, xfrm)) {
fe1a5f03	133	saved++;
fe1a5f03	134	} else {
8e479560 TT	135	deleted++;
	136	hlist_del(&fle->u.hlist);
	137	list_add_tail(&fle->u.gc_list, &gc_list);
fe1a5f03	138	}
1da177e4 LT	139	}
1da177e4 LT	140	}
8e479560	141
ca925cf1	142	flow_cache_queue_garbage(fcp, deleted, &gc_list, xfrm);
1da177e4 LT	143	}
1da177e4 LT	144
d7997fe1 TT	145	static void flow_cache_shrink(struct flow_cache *fc,
d7997fe1 TT	146	struct flow_cache_percpu *fcp)
1da177e4	147	{
d7997fe1	148	int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);
1da177e4	149
d7997fe1	150	__flow_cache_shrink(fc, fcp, shrink_to);
1da177e4 LT	151	}
1da177e4 LT	152
d7997fe1 TT	153	static void flow_new_hash_rnd(struct flow_cache *fc,
d7997fe1 TT	154	struct flow_cache_percpu *fcp)
1da177e4	155	{
d7997fe1 TT	156	get_random_bytes(&fcp->hash_rnd, sizeof(u32));
	157	fcp->hash_rnd_recalc = 0;
	158	__flow_cache_shrink(fc, fcp, 0);
1da177e4 LT	159	}
1da177e4 LT	160
d7997fe1 TT	161	static u32 flow_hash_code(struct flow_cache *fc,
d7997fe1 TT	162	struct flow_cache_percpu *fcp,
aa1c366e	163	const struct flowi *key,
aa1c366e	164	size_t keysize)
1da177e4	165	{
dee9f4bc	166	const u32 k = (const u32 ) key;
aa1c366e	167	const u32 length = keysize * sizeof(flow_compare_t) / sizeof(u32);
1da177e4	168
aa1c366e	169	return jhash2(k, length, fcp->hash_rnd)
a02cec21	170	& (flow_cache_hash_size(fc) - 1);
1da177e4 LT	171	}
1da177e4 LT	172
1da177e4	173	/* I hear what you're saying, use memcmp. But memcmp cannot make
aa1c366e	174	* important assumptions that we can here, such as alignment.
1da177e4	175	*/
aa1c366e	176	static int flow_key_compare(const struct flowi key1, const struct flowi key2,
aa1c366e	177	size_t keysize)
1da177e4	178	{
dee9f4bc	179	const flow_compare_t k1, k1_lim, *k2;
1da177e4	180
dee9f4bc	181	k1 = (const flow_compare_t *) key1;
aa1c366e	182	k1_lim = k1 + keysize;
1da177e4	183
dee9f4bc	184	k2 = (const flow_compare_t *) key2;
1da177e4 LT	185
	186	do {
	187	if (k1++ != k2++)
	188	return 1;
	189	} while (k1 < k1_lim);
	190
	191	return 0;
	192	}
	193
fe1a5f03	194	struct flow_cache_object *
dee9f4bc	195	flow_cache_lookup(struct net net, const struct flowi key, u16 family, u8 dir,
fe1a5f03	196	flow_resolve_t resolver, void *ctx)
1da177e4	197	{
ca925cf1	198	struct flow_cache *fc = &net->xfrm.flow_cache_global;
d7997fe1	199	struct flow_cache_percpu *fcp;
8e479560	200	struct flow_cache_entry fle, tfle;
fe1a5f03	201	struct flow_cache_object *flo;
aa1c366e	202	size_t keysize;
1da177e4	203	unsigned int hash;
1da177e4 LT	204
1da177e4 LT	205	local_bh_disable();
7a9b2d59	206	fcp = this_cpu_ptr(fc->percpu);
1da177e4 LT	207
1da177e4 LT	208	fle = NULL;
fe1a5f03	209	flo = NULL;
aa1c366e	210
	211	keysize = flow_key_size(family);
	212	if (!keysize)
	213	goto nocache;
	214
1da177e4 LT	215	/* Packet really early in init? Making flow_cache_init a
1da177e4 LT	216	* pre-smp initcall would solve this. --RR */
d7997fe1	217	if (!fcp->hash_table)
1da177e4 LT	218	goto nocache;
1da177e4 LT	219
d7997fe1 TT	220	if (fcp->hash_rnd_recalc)
d7997fe1 TT	221	flow_new_hash_rnd(fc, fcp);
1da177e4	222
aa1c366e	223	hash = flow_hash_code(fc, fcp, key, keysize);
b67bfe0d	224	hlist_for_each_entry(tfle, &fcp->hash_table[hash], u.hlist) {
0542b69e	225	if (tfle->net == net &&
0542b69e	226	tfle->family == family &&
8e479560	227	tfle->dir == dir &&
aa1c366e	228	flow_key_compare(key, &tfle->key, keysize) == 0) {
8e479560	229	fle = tfle;
1da177e4	230	break;
8e479560	231	}
1da177e4 LT	232	}
1da177e4 LT	233
fe1a5f03	234	if (unlikely(!fle)) {
d7997fe1 TT	235	if (fcp->hash_count > fc->high_watermark)
d7997fe1 TT	236	flow_cache_shrink(fc, fcp);
1da177e4	237
6b226487 MU	238	if (atomic_read(&net->xfrm.flow_cache_gc_count) >
6b226487 MU	239	2 * num_online_cpus() * fc->high_watermark) {
6ad3122a SK	240	flo = ERR_PTR(-ENOBUFS);
	241	goto ret_object;
	242	}
	243
d32d9bb8	244	fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
1da177e4	245	if (fle) {
0542b69e	246	fle->net = net;
1da177e4 LT	247	fle->family = family;
1da177e4 LT	248	fle->dir = dir;
aa1c366e	249	memcpy(&fle->key, key, keysize * sizeof(flow_compare_t));
1da177e4	250	fle->object = NULL;
8e479560	251	hlist_add_head(&fle->u.hlist, &fcp->hash_table[hash]);
d7997fe1	252	fcp->hash_count++;
1da177e4	253	}
ca925cf1	254	} else if (likely(fle->genid == atomic_read(&net->xfrm.flow_cache_genid))) {
fe1a5f03 TT	255	flo = fle->object;
	256	if (!flo)
	257	goto ret_object;
	258	flo = flo->ops->get(flo);
	259	if (flo)
	260	goto ret_object;
	261	} else if (fle->object) {
	262	flo = fle->object;
	263	flo->ops->delete(flo);
	264	fle->object = NULL;
1da177e4 LT	265	}
	266
	267	nocache:
fe1a5f03 TT	268	flo = NULL;
	269	if (fle) {
	270	flo = fle->object;
	271	fle->object = NULL;
	272	}
	273	flo = resolver(net, key, family, dir, flo, ctx);
	274	if (fle) {
ca925cf1	275	fle->genid = atomic_read(&net->xfrm.flow_cache_genid);
fe1a5f03 TT	276	if (!IS_ERR(flo))
	277	fle->object = flo;
	278	else
	279	fle->genid--;
	280	} else {
8fbcec24	281	if (!IS_ERR_OR_NULL(flo))
fe1a5f03	282	flo->ops->delete(flo);
1da177e4	283	}
fe1a5f03 TT	284	ret_object:
	285	local_bh_enable();
	286	return flo;
1da177e4	287	}
9e34a5b5	288	EXPORT_SYMBOL(flow_cache_lookup);
1da177e4 LT	289
	290	static void flow_cache_flush_tasklet(unsigned long data)
	291	{
	292	struct flow_flush_info info = (void )data;
d7997fe1 TT	293	struct flow_cache *fc = info->cache;
d7997fe1 TT	294	struct flow_cache_percpu *fcp;
8e479560	295	struct flow_cache_entry *fle;
b67bfe0d	296	struct hlist_node *tmp;
8e479560 TT	297	LIST_HEAD(gc_list);
8e479560 TT	298	int i, deleted = 0;
ca925cf1 FD	299	struct netns_xfrm *xfrm = container_of(fc, struct netns_xfrm,
ca925cf1 FD	300	flow_cache_global);
1da177e4	301
7a9b2d59	302	fcp = this_cpu_ptr(fc->percpu);
d7997fe1	303	for (i = 0; i < flow_cache_hash_size(fc); i++) {
b67bfe0d	304	hlist_for_each_entry_safe(fle, tmp,
8e479560	305	&fcp->hash_table[i], u.hlist) {
ca925cf1	306	if (flow_entry_valid(fle, xfrm))
1da177e4 LT	307	continue;
1da177e4 LT	308
8e479560 TT	309	deleted++;
	310	hlist_del(&fle->u.hlist);
	311	list_add_tail(&fle->u.gc_list, &gc_list);
1da177e4 LT	312	}
	313	}
	314
ca925cf1	315	flow_cache_queue_garbage(fcp, deleted, &gc_list, xfrm);
8e479560	316
1da177e4 LT	317	if (atomic_dec_and_test(&info->cpuleft))
	318	complete(&info->completion);
	319	}
	320
8fdc929f CM	321	/*
	322	* Return whether a cpu needs flushing. Conservatively, we assume
	323	* the presence of any entries means the core may require flushing,
	324	* since the flow_cache_ops.check() function may assume it's running
	325	* on the same core as the per-cpu cache component.
	326	*/
	327	static int flow_cache_percpu_empty(struct flow_cache *fc, int cpu)
	328	{
	329	struct flow_cache_percpu *fcp;
	330	int i;
	331
27815032	332	fcp = per_cpu_ptr(fc->percpu, cpu);
8fdc929f CM	333	for (i = 0; i < flow_cache_hash_size(fc); i++)
	334	if (!hlist_empty(&fcp->hash_table[i]))
	335	return 0;
	336	return 1;
	337	}
	338
1da177e4 LT	339	static void flow_cache_flush_per_cpu(void *data)
	340	{
	341	struct flow_flush_info *info = data;
1da177e4 LT	342	struct tasklet_struct *tasklet;
1da177e4 LT	343
50eab050	344	tasklet = &this_cpu_ptr(info->cache->percpu)->flush_tasklet;
1da177e4 LT	345	tasklet->data = (unsigned long)info;
	346	tasklet_schedule(tasklet);
	347	}
	348
ca925cf1	349	void flow_cache_flush(struct net *net)
1da177e4 LT	350	{
1da177e4 LT	351	struct flow_flush_info info;
8fdc929f CM	352	cpumask_var_t mask;
	353	int i, self;
	354
	355	/* Track which cpus need flushing to avoid disturbing all cores. */
	356	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
	357	return;
	358	cpumask_clear(mask);
1da177e4 LT	359
1da177e4 LT	360	/* Don't want cpus going down or up during this. */
86ef5c9a	361	get_online_cpus();
ca925cf1 FD	362	mutex_lock(&net->xfrm.flow_flush_sem);
ca925cf1 FD	363	info.cache = &net->xfrm.flow_cache_global;
8fdc929f CM	364	for_each_online_cpu(i)
	365	if (!flow_cache_percpu_empty(info.cache, i))
	366	cpumask_set_cpu(i, mask);
	367	atomic_set(&info.cpuleft, cpumask_weight(mask));
	368	if (atomic_read(&info.cpuleft) == 0)
	369	goto done;
	370
1da177e4 LT	371	init_completion(&info.completion);
	372
	373	local_bh_disable();
8fdc929f CM	374	self = cpumask_test_and_clear_cpu(smp_processor_id(), mask);
	375	on_each_cpu_mask(mask, flow_cache_flush_per_cpu, &info, 0);
	376	if (self)
	377	flow_cache_flush_tasklet((unsigned long)&info);
1da177e4 LT	378	local_bh_enable();
	379
	380	wait_for_completion(&info.completion);
8fdc929f CM	381
8fdc929f CM	382	done:
ca925cf1	383	mutex_unlock(&net->xfrm.flow_flush_sem);
86ef5c9a	384	put_online_cpus();
8fdc929f	385	free_cpumask_var(mask);
1da177e4 LT	386	}
1da177e4 LT	387
c0ed1c14 SK	388	static void flow_cache_flush_task(struct work_struct *work)
c0ed1c14 SK	389	{
ca925cf1	390	struct netns_xfrm *xfrm = container_of(work, struct netns_xfrm,
233c96fc	391	flow_cache_flush_work);
ca925cf1	392	struct net *net = container_of(xfrm, struct net, xfrm);
c0ed1c14	393
ca925cf1 FD	394	flow_cache_flush(net);
ca925cf1 FD	395	}
c0ed1c14	396
ca925cf1	397	void flow_cache_flush_deferred(struct net *net)
c0ed1c14	398	{
ca925cf1	399	schedule_work(&net->xfrm.flow_cache_flush_work);
c0ed1c14 SK	400	}
c0ed1c14 SK	401
013dbb32	402	static int flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
1da177e4	403	{
83b6b1f5 ED	404	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
83b6b1f5 ED	405	size_t sz = sizeof(struct hlist_head) * flow_cache_hash_size(fc);
d7997fe1	406
83b6b1f5 ED	407	if (!fcp->hash_table) {
	408	fcp->hash_table = kzalloc_node(sz, GFP_KERNEL, cpu_to_node(cpu));
	409	if (!fcp->hash_table) {
	410	pr_err("NET: failed to allocate flow cache sz %zu\n", sz);
	411	return -ENOMEM;
	412	}
	413	fcp->hash_rnd_recalc = 1;
	414	fcp->hash_count = 0;
	415	tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
	416	}
	417	return 0;
1da177e4 LT	418	}
1da177e4 LT	419
a4fc1bfc	420	static int flow_cache_cpu_up_prep(unsigned int cpu, struct hlist_node *node)
1da177e4	421	{
a4fc1bfc SAS	422	struct flow_cache *fc = hlist_entry_safe(node, struct flow_cache, node);
	423
	424	return flow_cache_cpu_prepare(fc, cpu);
	425	}
	426
	427	static int flow_cache_cpu_dead(unsigned int cpu, struct hlist_node *node)
	428	{
	429	struct flow_cache *fc = hlist_entry_safe(node, struct flow_cache, node);
d7997fe1 TT	430	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
d7997fe1 TT	431
a4fc1bfc SAS	432	__flow_cache_shrink(fc, fcp, 0);
a4fc1bfc SAS	433	return 0;
1da177e4	434	}
1da177e4	435
ca925cf1	436	int flow_cache_init(struct net *net)
1da177e4 LT	437	{
1da177e4 LT	438	int i;
ca925cf1 FD	439	struct flow_cache *fc = &net->xfrm.flow_cache_global;
ca925cf1 FD	440
d32d9bb8 ED	441	if (!flow_cachep)
	442	flow_cachep = kmem_cache_create("flow_cache",
	443	sizeof(struct flow_cache_entry),
	444	0, SLAB_PANIC, NULL);
ca925cf1 FD	445	spin_lock_init(&net->xfrm.flow_cache_gc_lock);
	446	INIT_LIST_HEAD(&net->xfrm.flow_cache_gc_list);
	447	INIT_WORK(&net->xfrm.flow_cache_gc_work, flow_cache_gc_task);
	448	INIT_WORK(&net->xfrm.flow_cache_flush_work, flow_cache_flush_task);
	449	mutex_init(&net->xfrm.flow_flush_sem);
6ad3122a	450	atomic_set(&net->xfrm.flow_cache_gc_count, 0);
1da177e4	451
d7997fe1 TT	452	fc->hash_shift = 10;
	453	fc->low_watermark = 2 * flow_cache_hash_size(fc);
	454	fc->high_watermark = 4 * flow_cache_hash_size(fc);
	455
d7997fe1	456	fc->percpu = alloc_percpu(struct flow_cache_percpu);
83b6b1f5 ED	457	if (!fc->percpu)
83b6b1f5 ED	458	return -ENOMEM;
1da177e4	459
a4fc1bfc SAS	460	if (cpuhp_state_add_instance(CPUHP_NET_FLOW_PREPARE, &fc->node))
a4fc1bfc SAS	461	goto err;
1da177e4	462
83b6b1f5 ED	463	setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
	464	(unsigned long) fc);
	465	fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
	466	add_timer(&fc->rnd_timer);
	467
1da177e4	468	return 0;
6ccc3abd	469
	470	err:
	471	for_each_possible_cpu(i) {
	472	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
	473	kfree(fcp->hash_table);
	474	fcp->hash_table = NULL;
	475	}
	476
	477	free_percpu(fc->percpu);
	478	fc->percpu = NULL;
	479
	480	return -ENOMEM;
1da177e4	481	}
ca925cf1	482	EXPORT_SYMBOL(flow_cache_init);
4a93f509 SK	483
	484	void flow_cache_fini(struct net *net)
	485	{
	486	int i;
	487	struct flow_cache *fc = &net->xfrm.flow_cache_global;
	488
	489	del_timer_sync(&fc->rnd_timer);
a4fc1bfc SAS	490
a4fc1bfc SAS	491	cpuhp_state_remove_instance_nocalls(CPUHP_NET_FLOW_PREPARE, &fc->node);
4a93f509 SK	492
	493	for_each_possible_cpu(i) {
	494	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
	495	kfree(fcp->hash_table);
	496	fcp->hash_table = NULL;
	497	}
	498
	499	free_percpu(fc->percpu);
	500	fc->percpu = NULL;
	501	}
	502	EXPORT_SYMBOL(flow_cache_fini);
a4fc1bfc SAS	503
	504	void __init flow_cache_hp_init(void)
	505	{
	506	int ret;
	507
	508	ret = cpuhp_setup_state_multi(CPUHP_NET_FLOW_PREPARE,
	509	"net/flow:prepare",
	510	flow_cache_cpu_up_prep,
	511	flow_cache_cpu_dead);
	512	WARN_ON(ret < 0);
	513	}