/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com * Copyright (c) 2016 Facebook * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */#include <linux/bpf.h>#include <linux/jhash.h>#include <linux/filter.h>#include <linux/vmalloc.h>#include "percpu_freelist.h" struct bucket {	struct hlist_head head;	raw_spinlock_t lock;}; struct bpf_htab {	struct bpf_map map;	struct bucket *buckets;	void *elems;	struct pcpu_freelist freelist;	atomic_t count;	/* number of elements in this hashtable */	u32 n_buckets;	/* number of hash buckets */	u32 elem_size;	/* size of each element in bytes */}; /* each htab element is struct htab_elem + key + value */struct htab_elem {	union {		struct hlist_node hash_node;		struct bpf_htab *htab;		struct pcpu_freelist_node fnode;	};	struct rcu_head rcu;	u32 hash;	char key[0] __aligned(8);}; static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,				     void __percpu *pptr){	*(void __percpu **)(l->key + key_size) = pptr;} static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size){	return *(void __percpu **)(l->key + key_size);} static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i){	return (struct htab_elem *) (htab->elems + i * htab->elem_size);} static void htab_free_elems(struct bpf_htab *htab){	int i; 	if (htab->map.map_type != BPF_MAP_TYPE_PERCPU_HASH)		goto free_elems; 	for (i = 0; i < htab->map.max_entries; i++) {		void __percpu *pptr; 		pptr = htab_elem_get_ptr(get_htab_elem(htab, i),					 htab->map.key_size);		free_percpu(pptr);	}free_elems:	vfree(htab->elems);} static int prealloc_elems_and_freelist(struct bpf_htab *htab){	int err = -ENOMEM, i; 	htab->elems = vzalloc(htab->elem_size * htab->map.max_entries);	if (!htab->elems)		return -ENOMEM; 	if (htab->map.map_type != BPF_MAP_TYPE_PERCPU_HASH)		goto skip_percpu_elems; 	for (i = 0; i < htab->map.max_entries; i++) {		u32 size = round_up(htab->map.value_size, 8);		void __percpu *pptr; 		pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN);		if (!pptr)			goto free_elems;		htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,				  pptr);	} skip_percpu_elems:	err = pcpu_freelist_init(&htab->freelist);	if (err)		goto free_elems; 	pcpu_freelist_populate(&htab->freelist, htab->elems, htab->elem_size,			       htab->map.max_entries);	return 0; free_elems:	htab_free_elems(htab);	return err;} /* Called from syscall */static struct bpf_map *htab_map_alloc(union bpf_attr *attr){	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_HASH;	struct bpf_htab *htab;	int err, i;	u64 cost; 	if (attr->map_flags & ~BPF_F_NO_PREALLOC)		/* reserved bits should not be used */		return ERR_PTR(-EINVAL); 	htab = kzalloc(sizeof(*htab), GFP_USER);	if (!htab)		return ERR_PTR(-ENOMEM); 	/* mandatory map attributes */	htab->map.map_type = attr->map_type;	htab->map.key_size = attr->key_size;	htab->map.value_size = attr->value_size;	htab->map.max_entries = attr->max_entries;	htab->map.map_flags = attr->map_flags; 	/* check sanity of attributes.	 * value_size == 0 may be allowed in the future to use map as a set	 */	err = -EINVAL;	if (htab->map.max_entries == 0 || htab->map.key_size == 0 ||	    htab->map.value_size == 0)		goto free_htab; 	/* hash table size must be power of 2 */	htab->n_buckets = roundup_pow_of_two(htab->map.max_entries); 	err = -E2BIG;	if (htab->map.key_size > MAX_BPF_STACK)		/* eBPF programs initialize keys on stack, so they cannot be		 * larger than max stack size		 */		goto free_htab; 	if (htab->map.value_size >= (1 << (KMALLOC_SHIFT_MAX - 1)) -	    MAX_BPF_STACK - sizeof(struct htab_elem))		/* if value_size is bigger, the user space won't be able to		 * access the elements via bpf syscall. This check also makes		 * sure that the elem_size doesn't overflow and it's		 * kmalloc-able later in htab_map_update_elem()		 */		goto free_htab; 	if (percpu && round_up(htab->map.value_size, 8) > PCPU_MIN_UNIT_SIZE)		/* make sure the size for pcpu_alloc() is reasonable */		goto free_htab; 	htab->elem_size = sizeof(struct htab_elem) +			  round_up(htab->map.key_size, 8);	if (percpu)		htab->elem_size += sizeof(void *);	else		htab->elem_size += round_up(htab->map.value_size, 8); 	/* prevent zero size kmalloc and check for u32 overflow */	if (htab->n_buckets == 0 ||	    htab->n_buckets > U32_MAX / sizeof(struct bucket))		goto free_htab; 	cost = (u64) htab->n_buckets * sizeof(struct bucket) +	       (u64) htab->elem_size * htab->map.max_entries; 	if (percpu)		cost += (u64) round_up(htab->map.value_size, 8) *			num_possible_cpus() * htab->map.max_entries; 	if (cost >= U32_MAX - PAGE_SIZE)		/* make sure page count doesn't overflow */		goto free_htab; 	htab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; 	/* if map size is larger than memlock limit, reject it early */	err = bpf_map_precharge_memlock(htab->map.pages);	if (err)		goto free_htab; 	err = -ENOMEM;	htab->buckets = kmalloc_array(htab->n_buckets, sizeof(struct bucket),				      GFP_USER | __GFP_NOWARN); 	if (!htab->buckets) {		htab->buckets = vmalloc(htab->n_buckets * sizeof(struct bucket));		if (!htab->buckets)			goto free_htab;	} 	for (i = 0; i < htab->n_buckets; i++) {		INIT_HLIST_HEAD(&htab->buckets[i].head);		raw_spin_lock_init(&htab->buckets[i].lock);	} 	if (!(attr->map_flags & BPF_F_NO_PREALLOC)) {		err = prealloc_elems_and_freelist(htab);		if (err)			goto free_buckets;	} 	return &htab->map; free_buckets:	kvfree(htab->buckets);free_htab:	kfree(htab);	return ERR_PTR(err);} static inline u32 htab_map_hash(const void *key, u32 key_len){	return jhash(key, key_len, 0);} static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash){	return &htab->buckets[hash & (htab->n_buckets - 1)];} static inline struct hlist_head *select_bucket(struct bpf_htab *htab, u32 hash){	return &__select_bucket(htab, hash)->head;} static struct htab_elem *lookup_elem_raw(struct hlist_head *head, u32 hash,					 void *key, u32 key_size){	struct htab_elem *l; 	hlist_for_each_entry_rcu(l, head, hash_node)		if (l->hash == hash && !memcmp(&l->key, key, key_size))			return l; 	return NULL;} /* Called from syscall or from eBPF program */static void *__htab_map_lookup_elem(struct bpf_map *map, void *key){	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);	struct hlist_head *head;	struct htab_elem *l;	u32 hash, key_size; 	/* Must be called with rcu_read_lock. */	WARN_ON_ONCE(!rcu_read_lock_held()); 	key_size = map->key_size; 	hash = htab_map_hash(key, key_size); 	head = select_bucket(htab, hash); 	l = lookup_elem_raw(head, hash, key, key_size); 	return l;} static void *htab_map_lookup_elem(struct bpf_map *map, void *key){	struct htab_elem *l = __htab_map_lookup_elem(map, key); 	if (l)		return l->key + round_up(map->key_size, 8); 	return NULL;} /* Called from syscall */static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key){	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);	struct hlist_head *head;	struct htab_elem *l, *next_l;	u32 hash, key_size;	int i; 	WARN_ON_ONCE(!rcu_read_lock_held()); 	key_size = map->key_size; 	hash = htab_map_hash(key, key_size); 	head = select_bucket(htab, hash); 	/* lookup the key */	l = lookup_elem_raw(head, hash, key, key_size); 	if (!l) {		i = 0;		goto find_first_elem;	} 	/* key was found, get next key in the same bucket */	next_l = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&l->hash_node)),				  struct htab_elem, hash_node); 	if (next_l) {		/* if next elem in this hash list is non-zero, just return it */		memcpy(next_key, next_l->key, key_size);		return 0;	} 	/* no more elements in this hash list, go to the next bucket */	i = hash & (htab->n_buckets - 1);	i++; find_first_elem:	/* iterate over buckets */	for (; i < htab->n_buckets; i++) {		head = select_bucket(htab, i); 		/* pick first element in the bucket */		next_l = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),					  struct htab_elem, hash_node);		if (next_l) {			/* if it's not empty, just return it */			memcpy(next_key, next_l->key, key_size);			return 0;		}	} 	/* iterated over all buckets and all elements */	return -ENOENT;} static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l){	if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)		free_percpu(htab_elem_get_ptr(l, htab->map.key_size));	kfree(l); } static void htab_elem_free_rcu(struct rcu_head *head){	struct htab_elem *l = container_of(head, struct htab_elem, rcu);	struct bpf_htab *htab = l->htab; 	/* must increment bpf_prog_active to avoid kprobe+bpf triggering while	 * we're calling kfree, otherwise deadlock is possible if kprobes	 * are placed somewhere inside of slub	 */	preempt_disable();	__this_cpu_inc(bpf_prog_active);	htab_elem_free(htab, l);	__this_cpu_dec(bpf_prog_active);	preempt_enable();} static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l){	if (!(htab->map.map_flags & BPF_F_NO_PREALLOC)) {		pcpu_freelist_push(&htab->freelist, &l->fnode);	} else {		atomic_dec(&htab->count);		l->htab = htab;		call_rcu(&l->rcu, htab_elem_free_rcu);	}} static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,					 void *value, u32 key_size, u32 hash,					 bool percpu, bool onallcpus){	u32 size = htab->map.value_size;	bool prealloc = !(htab->map.map_flags & BPF_F_NO_PREALLOC);	struct htab_elem *l_new;	void __percpu *pptr; 	if (prealloc) {		l_new = (struct htab_elem *)pcpu_freelist_pop(&htab->freelist);		if (!l_new)			return ERR_PTR(-E2BIG);	} else {		if (atomic_inc_return(&htab->count) > htab->map.max_entries) {			atomic_dec(&htab->count);			return ERR_PTR(-E2BIG);		}		l_new = kmalloc(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN);		if (!l_new)			return ERR_PTR(-ENOMEM);	} 	memcpy(l_new->key, key, key_size);	if (percpu) {		/* round up value_size to 8 bytes */		size = round_up(size, 8); 		if (prealloc) {			pptr = htab_elem_get_ptr(l_new, key_size);		} else {			/* alloc_percpu zero-fills */			pptr = __alloc_percpu_gfp(size, 8,						  GFP_ATOMIC | __GFP_NOWARN);			if (!pptr) {				kfree(l_new);				return ERR_PTR(-ENOMEM);			}		} 		if (!onallcpus) {			/* copy true value_size bytes */			memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);		} else {			int off = 0, cpu; 			for_each_possible_cpu(cpu) {				bpf_long_memcpy(per_cpu_ptr(pptr, cpu),						value + off, size);				off += size;			}		}		if (!prealloc)			htab_elem_set_ptr(l_new, key_size, pptr);	} else {		memcpy(l_new->key + round_up(key_size, 8), value, size);	} 	l_new->hash = hash;	return l_new;} static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,		       u64 map_flags){	if (l_old && map_flags == BPF_NOEXIST)		/* elem already exists */		return -EEXIST; 	if (!l_old && map_flags == BPF_EXIST)		/* elem doesn't exist, cannot update it */		return -ENOENT; 	return 0;} /* Called from syscall or from eBPF program */static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,				u64 map_flags){	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);	struct htab_elem *l_new = NULL, *l_old;	struct hlist_head *head;	unsigned long flags;	struct bucket *b;	u32 key_size, hash;	int ret; 	if (unlikely(map_flags > BPF_EXIST))		/* unknown flags */		return -EINVAL; 	WARN_ON_ONCE(!rcu_read_lock_held()); 	key_size = map->key_size; 	hash = htab_map_hash(key, key_size); 	b = __select_bucket(htab, hash);	head = &b->head; 	/* bpf_map_update_elem() can be called in_irq() */	raw_spin_lock_irqsave(&b->lock, flags); 	l_old = lookup_elem_raw(head, hash, key, key_size); 	ret = check_flags(htab, l_old, map_flags);	if (ret)		goto err; 	l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false);	if (IS_ERR(l_new)) {		/* all pre-allocated elements are in use or memory exhausted */		ret = PTR_ERR(l_new);		goto err;	} 	/* add new element to the head of the list, so that	 * concurrent search will find it before old elem

Lines 1–500 of 745. Load more