net/core/flow.c - kernel/msm-4.9 - Gitiles

 /* 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 <asm/atomic.h>
 #include <linux/security.h>

 struct flow_cache_entry {
 	struct flow_cache_entry		*next;
 	u16				family;
 	u8				dir;
 	u32				genid;
 	struct flowi			key;
 	struct flow_cache_object	*object;
 };

 struct flow_cache_percpu {
 	struct flow_cache_entry		**hash_table;
 	int				hash_count;
 	u32				hash_rnd;
 	int				hash_rnd_recalc;
 	struct tasklet_struct		flush_tasklet;
 };

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

 struct flow_cache {
 	u32				hash_shift;
 	unsigned long			order;
 	struct flow_cache_percpu	*percpu;
 	struct notifier_block		hotcpu_notifier;
 	int				low_watermark;
 	int				high_watermark;
 	struct timer_list		rnd_timer;
 };

 atomic_t flow_cache_genid = ATOMIC_INIT(0);
 static struct flow_cache flow_cache_global;
 static struct kmem_cache *flow_cachep;

 #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)
 {
 	if (atomic_read(&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 *fc,
 			    struct flow_cache_percpu *fcp,
 			    struct flow_cache_entry *fle)
 {
 	if (fle->object)
 		fle->object->ops->delete(fle->object);
 	kmem_cache_free(flow_cachep, fle);
 	fcp->hash_count--;
 }

 static void __flow_cache_shrink(struct flow_cache *fc,
 				struct flow_cache_percpu *fcp,
 				int shrink_to)
 {
 	struct flow_cache_entry *fle, **flp;
 	int i;

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

 		flp = &fcp->hash_table[i];
 		while ((fle = *flp) != NULL) {
 			if (saved < shrink_to &&
 			    flow_entry_valid(fle)) {
 				saved++;
 				flp = &fle->next;
 			} else {
 				*flp = fle->next;
 				flow_entry_kill(fc, fcp, fle);
 			}
 		}
 	}
 }

 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,
 			  struct flowi *key)
 {
 	u32 *k = (u32 *) key;

 	return (jhash2(k, (sizeof(*key) / sizeof(u32)), fcp->hash_rnd)
 		& (flow_cache_hash_size(fc) - 1));
 }

 #if (BITS_PER_LONG == 64)
 typedef u64 flow_compare_t;
 #else
 typedef u32 flow_compare_t;
 #endif

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

 	BUILD_BUG_ON(sizeof(struct flowi) % sizeof(flow_compare_t));

 	k1 = (flow_compare_t *) key1;
 	k1_lim = k1 + n_elem;

 	k2 = (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, struct flowi *key, u16 family, u8 dir,
 		  flow_resolve_t resolver, void *ctx)
 {
 	struct flow_cache *fc = &flow_cache_global;
 	struct flow_cache_percpu *fcp;
 	struct flow_cache_entry *fle, **head;
 	struct flow_cache_object *flo;
 	unsigned int hash;

 	local_bh_disable();
 	fcp = per_cpu_ptr(fc->percpu, smp_processor_id());

 	fle = NULL;
 	flo = NULL;
 	/* 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);
 	head = &fcp->hash_table[hash];
 	for (fle = *head; fle; fle = fle->next) {
 		if (fle->family == family &&
 		    fle->dir == dir &&
 		    flow_key_compare(key, &fle->key) == 0)
 			break;
 	}

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

 		fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
 		if (fle) {
 			fle->next = *head;
 			*head = fle;
 			fle->family = family;
 			fle->dir = dir;
 			memcpy(&fle->key, key, sizeof(*key));
 			fle->object = NULL;
 			fcp->hash_count++;
 		}
 	} else if (likely(fle->genid == atomic_read(&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(&flow_cache_genid);
 		if (!IS_ERR(flo))
 			fle->object = flo;
 		else
 			fle->genid--;
 	} else {
 		if (flo && !IS_ERR(flo))
 			flo->ops->delete(flo);
 	}
 ret_object:
 	local_bh_enable();
 	return flo;
 }

 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;
 	int i;

 	fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
 	for (i = 0; i < flow_cache_hash_size(fc); i++) {
 		struct flow_cache_entry *fle;

 		fle = fcp->hash_table[i];
 		for (; fle; fle = fle->next) {
 			if (flow_entry_valid(fle))
 				continue;

 			if (fle->object)
 				fle->object->ops->delete(fle->object);
 			fle->object = NULL;
 		}
 	}

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

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

 	cpu = smp_processor_id();
 	tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
 	tasklet->data = (unsigned long)info;
 	tasklet_schedule(tasklet);
 }

 void flow_cache_flush(void)
 {
 	struct flow_flush_info info;
 	static DEFINE_MUTEX(flow_flush_sem);

 	/* Don't want cpus going down or up during this. */
 	get_online_cpus();
 	mutex_lock(&flow_flush_sem);
 	info.cache = &flow_cache_global;
 	atomic_set(&info.cpuleft, num_online_cpus());
 	init_completion(&info.completion);

 	local_bh_disable();
 	smp_call_function(flow_cache_flush_per_cpu, &info, 0);
 	flow_cache_flush_tasklet((unsigned long)&info);
 	local_bh_enable();

 	wait_for_completion(&info.completion);
 	mutex_unlock(&flow_flush_sem);
 	put_online_cpus();
 }

 static void __init flow_cache_cpu_prepare(struct flow_cache *fc,
 					  struct flow_cache_percpu *fcp)
 {
 	fcp->hash_table = (struct flow_cache_entry **)
 		__get_free_pages(GFP_KERNEL|__GFP_ZERO, fc->order);
 	if (!fcp->hash_table)
 		panic("NET: failed to allocate flow cache order %lu\n", fc->order);

 	fcp->hash_rnd_recalc = 1;
 	fcp->hash_count = 0;
 	tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
 }

 static int flow_cache_cpu(struct notifier_block *nfb,
 			  unsigned long action,
 			  void *hcpu)
 {
 	struct flow_cache *fc = container_of(nfb, struct flow_cache, hotcpu_notifier);
 	int cpu = (unsigned long) hcpu;
 	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);

 	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
 		__flow_cache_shrink(fc, fcp, 0);
 	return NOTIFY_OK;
 }

 static int flow_cache_init(struct flow_cache *fc)
 {
 	unsigned long order;
 	int i;

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

 	for (order = 0;
 	     (PAGE_SIZE << order) <
 		     (sizeof(struct flow_cache_entry *)*flow_cache_hash_size(fc));
 	     order++)
 		/* NOTHING */;
 	fc->order = order;
 	fc->percpu = alloc_percpu(struct flow_cache_percpu);

 	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);

 	for_each_possible_cpu(i)
 		flow_cache_cpu_prepare(fc, per_cpu_ptr(fc->percpu, i));

 	fc->hotcpu_notifier = (struct notifier_block){
 		.notifier_call = flow_cache_cpu,
 	};
 	register_hotcpu_notifier(&fc->hotcpu_notifier);

 	return 0;
 }

 static int __init flow_cache_init_global(void)
 {
 	flow_cachep = kmem_cache_create("flow_cache",
 					sizeof(struct flow_cache_entry),
 					0, SLAB_PANIC, NULL);

 	return flow_cache_init(&flow_cache_global);
 }

 module_init(flow_cache_init_global);

 EXPORT_SYMBOL(flow_cache_genid);
 EXPORT_SYMBOL(flow_cache_lookup);
	/* 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 <asm/atomic.h>
	#include <linux/security.h>

	struct flow_cache_entry {
	struct flow_cache_entry *next;
	u16 family;
	u8 dir;
	u32 genid;
	struct flowi key;
	struct flow_cache_object *object;
	};

	struct flow_cache_percpu {
	struct flow_cache_entry **hash_table;
	int hash_count;
	u32 hash_rnd;
	int hash_rnd_recalc;
	struct tasklet_struct flush_tasklet;
	};

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

	struct flow_cache {
	u32 hash_shift;
	unsigned long order;
	struct flow_cache_percpu *percpu;
	struct notifier_block hotcpu_notifier;
	int low_watermark;
	int high_watermark;
	struct timer_list rnd_timer;
	};

	atomic_t flow_cache_genid = ATOMIC_INIT(0);
	static struct flow_cache flow_cache_global;
	static struct kmem_cache *flow_cachep;

	#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)
	{
	if (atomic_read(&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 *fc,
	struct flow_cache_percpu *fcp,
	struct flow_cache_entry *fle)
	{
	if (fle->object)
	fle->object->ops->delete(fle->object);
	kmem_cache_free(flow_cachep, fle);
	fcp->hash_count--;
	}

	static void __flow_cache_shrink(struct flow_cache *fc,
	struct flow_cache_percpu *fcp,
	int shrink_to)
	{
	struct flow_cache_entry fle, *flp;
	int i;

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

	flp = &fcp->hash_table[i];
	while ((fle = *flp) != NULL) {
	if (saved < shrink_to &&
	flow_entry_valid(fle)) {
	saved++;
	flp = &fle->next;
	} else {
	*flp = fle->next;
	flow_entry_kill(fc, fcp, fle);
	}
	}
	}
	}

	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,
	struct flowi *key)
	{
	u32 k = (u32 ) key;

	return (jhash2(k, (sizeof(*key) / sizeof(u32)), fcp->hash_rnd)
	& (flow_cache_hash_size(fc) - 1));
	}

	#if (BITS_PER_LONG == 64)
	typedef u64 flow_compare_t;
	#else
	typedef u32 flow_compare_t;
	#endif

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

	BUILD_BUG_ON(sizeof(struct flowi) % sizeof(flow_compare_t));

	k1 = (flow_compare_t *) key1;
	k1_lim = k1 + n_elem;

	k2 = (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, struct flowi key, u16 family, u8 dir,
	flow_resolve_t resolver, void *ctx)
	{
	struct flow_cache *fc = &flow_cache_global;
	struct flow_cache_percpu *fcp;
	struct flow_cache_entry fle, *head;
	struct flow_cache_object *flo;
	unsigned int hash;

	local_bh_disable();
	fcp = per_cpu_ptr(fc->percpu, smp_processor_id());

	fle = NULL;
	flo = NULL;
	/* 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);
	head = &fcp->hash_table[hash];
	for (fle = *head; fle; fle = fle->next) {
	if (fle->family == family &&
	fle->dir == dir &&
	flow_key_compare(key, &fle->key) == 0)
	break;
	}

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

	fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
	if (fle) {
	fle->next = *head;
	*head = fle;
	fle->family = family;
	fle->dir = dir;
	memcpy(&fle->key, key, sizeof(*key));
	fle->object = NULL;
	fcp->hash_count++;
	}
	} else if (likely(fle->genid == atomic_read(&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(&flow_cache_genid);
	if (!IS_ERR(flo))
	fle->object = flo;
	else
	fle->genid--;
	} else {
	if (flo && !IS_ERR(flo))
	flo->ops->delete(flo);
	}
	ret_object:
	local_bh_enable();
	return flo;
	}

	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;
	int i;

	fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
	for (i = 0; i < flow_cache_hash_size(fc); i++) {
	struct flow_cache_entry *fle;

	fle = fcp->hash_table[i];
	for (; fle; fle = fle->next) {
	if (flow_entry_valid(fle))
	continue;

	if (fle->object)
	fle->object->ops->delete(fle->object);
	fle->object = NULL;
	}
	}

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

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

	cpu = smp_processor_id();
	tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
	tasklet->data = (unsigned long)info;
	tasklet_schedule(tasklet);
	}

	void flow_cache_flush(void)
	{
	struct flow_flush_info info;
	static DEFINE_MUTEX(flow_flush_sem);

	/* Don't want cpus going down or up during this. */
	get_online_cpus();
	mutex_lock(&flow_flush_sem);
	info.cache = &flow_cache_global;
	atomic_set(&info.cpuleft, num_online_cpus());
	init_completion(&info.completion);

	local_bh_disable();
	smp_call_function(flow_cache_flush_per_cpu, &info, 0);
	flow_cache_flush_tasklet((unsigned long)&info);
	local_bh_enable();

	wait_for_completion(&info.completion);
	mutex_unlock(&flow_flush_sem);
	put_online_cpus();
	}

	static void __init flow_cache_cpu_prepare(struct flow_cache *fc,
	struct flow_cache_percpu *fcp)
	{
	fcp->hash_table = (struct flow_cache_entry **)
	__get_free_pages(GFP_KERNEL\|__GFP_ZERO, fc->order);
	if (!fcp->hash_table)
	panic("NET: failed to allocate flow cache order %lu\n", fc->order);

	fcp->hash_rnd_recalc = 1;
	fcp->hash_count = 0;
	tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
	}

	static int flow_cache_cpu(struct notifier_block *nfb,
	unsigned long action,
	void *hcpu)
	{
	struct flow_cache *fc = container_of(nfb, struct flow_cache, hotcpu_notifier);
	int cpu = (unsigned long) hcpu;
	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);

	if (action == CPU_DEAD \|\| action == CPU_DEAD_FROZEN)
	__flow_cache_shrink(fc, fcp, 0);
	return NOTIFY_OK;
	}

	static int flow_cache_init(struct flow_cache *fc)
	{
	unsigned long order;
	int i;

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

	for (order = 0;
	(PAGE_SIZE << order) <
	(sizeof(struct flow_cache_entry )flow_cache_hash_size(fc));
	order++)
	/* NOTHING */;
	fc->order = order;
	fc->percpu = alloc_percpu(struct flow_cache_percpu);

	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);

	for_each_possible_cpu(i)
	flow_cache_cpu_prepare(fc, per_cpu_ptr(fc->percpu, i));

	fc->hotcpu_notifier = (struct notifier_block){
	.notifier_call = flow_cache_cpu,
	};
	register_hotcpu_notifier(&fc->hotcpu_notifier);

	return 0;
	}

	static int __init flow_cache_init_global(void)
	{
	flow_cachep = kmem_cache_create("flow_cache",
	sizeof(struct flow_cache_entry),
	0, SLAB_PANIC, NULL);

	return flow_cache_init(&flow_cache_global);
	}

	module_init(flow_cache_init_global);

	EXPORT_SYMBOL(flow_cache_genid);
	EXPORT_SYMBOL(flow_cache_lookup);