| /* 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> |
| |
| 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_cache_percpu { |
| struct hlist_head *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; |
| struct flow_cache_percpu __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); |
| EXPORT_SYMBOL(flow_cache_genid); |
| static struct flow_cache flow_cache_global; |
| static struct kmem_cache *flow_cachep __read_mostly; |
| |
| static DEFINE_SPINLOCK(flow_cache_gc_lock); |
| static LIST_HEAD(flow_cache_gc_list); |
| |
| #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_entry *fle) |
| { |
| 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; |
| |
| INIT_LIST_HEAD(&gc_list); |
| spin_lock_bh(&flow_cache_gc_lock); |
| list_splice_tail_init(&flow_cache_gc_list, &gc_list); |
| spin_unlock_bh(&flow_cache_gc_lock); |
| |
| list_for_each_entry_safe(fce, n, &gc_list, u.gc_list) |
| flow_entry_kill(fce); |
| } |
| static DECLARE_WORK(flow_cache_gc_work, flow_cache_gc_task); |
| |
| static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp, |
| int deleted, struct list_head *gc_list) |
| { |
| if (deleted) { |
| fcp->hash_count -= deleted; |
| spin_lock_bh(&flow_cache_gc_lock); |
| list_splice_tail(gc_list, &flow_cache_gc_list); |
| spin_unlock_bh(&flow_cache_gc_lock); |
| schedule_work(&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; |
| |
| 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)) { |
| 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); |
| } |
| |
| 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 = &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); |
| |
| 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(&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 (!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; |
| |
| 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)) |
| continue; |
| |
| deleted++; |
| hlist_del(&fle->u.hlist); |
| list_add_tail(&fle->u.gc_list, &gc_list); |
| } |
| } |
| |
| flow_cache_queue_garbage(fcp, deleted, &gc_list); |
| |
| 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(void) |
| { |
| struct flow_flush_info info; |
| static DEFINE_MUTEX(flow_flush_sem); |
| 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(&flow_flush_sem); |
| info.cache = &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(&flow_flush_sem); |
| put_online_cpus(); |
| free_cpumask_var(mask); |
| } |
| |
| static void flow_cache_flush_task(struct work_struct *work) |
| { |
| flow_cache_flush(); |
| } |
| |
| static DECLARE_WORK(flow_cache_flush_work, flow_cache_flush_task); |
| |
| void flow_cache_flush_deferred(void) |
| { |
| schedule_work(&flow_cache_flush_work); |
| } |
| |
| static int __cpuinit 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 __cpuinit 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 res, cpu = (unsigned long) hcpu; |
| struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu); |
| |
| switch (action) { |
| case CPU_UP_PREPARE: |
| case CPU_UP_PREPARE_FROZEN: |
| res = flow_cache_cpu_prepare(fc, cpu); |
| if (res) |
| return notifier_from_errno(res); |
| break; |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| __flow_cache_shrink(fc, fcp, 0); |
| break; |
| } |
| return NOTIFY_OK; |
| } |
| |
| static int __init flow_cache_init(struct flow_cache *fc) |
| { |
| int i; |
| |
| 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; |
| |
| cpu_notifier_register_begin(); |
| |
| for_each_online_cpu(i) { |
| if (flow_cache_cpu_prepare(fc, i)) |
| goto err; |
| } |
| fc->hotcpu_notifier = (struct notifier_block){ |
| .notifier_call = flow_cache_cpu, |
| }; |
| __register_hotcpu_notifier(&fc->hotcpu_notifier); |
| |
| cpu_notifier_register_done(); |
| |
| 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; |
| } |
| |
| cpu_notifier_register_done(); |
| |
| free_percpu(fc->percpu); |
| fc->percpu = NULL; |
| |
| return -ENOMEM; |
| } |
| |
| 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); |