diff options
Diffstat (limited to 'net/openvswitch/flow_table.c')
| -rw-r--r-- | net/openvswitch/flow_table.c | 1223 |
1 files changed, 1223 insertions, 0 deletions
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c new file mode 100644 index 0000000000..4f3b1798e0 --- /dev/null +++ b/net/openvswitch/flow_table.c @@ -0,0 +1,1223 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2007-2014 Nicira, Inc. + */ + +#include "flow.h" +#include "datapath.h" +#include "flow_netlink.h" +#include <linux/uaccess.h> +#include <linux/netdevice.h> +#include <linux/etherdevice.h> +#include <linux/if_ether.h> +#include <linux/if_vlan.h> +#include <net/llc_pdu.h> +#include <linux/kernel.h> +#include <linux/jhash.h> +#include <linux/jiffies.h> +#include <linux/llc.h> +#include <linux/module.h> +#include <linux/in.h> +#include <linux/rcupdate.h> +#include <linux/cpumask.h> +#include <linux/if_arp.h> +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <linux/sctp.h> +#include <linux/tcp.h> +#include <linux/udp.h> +#include <linux/icmp.h> +#include <linux/icmpv6.h> +#include <linux/rculist.h> +#include <linux/sort.h> +#include <net/ip.h> +#include <net/ipv6.h> +#include <net/ndisc.h> + +#define TBL_MIN_BUCKETS 1024 +#define MASK_ARRAY_SIZE_MIN 16 +#define REHASH_INTERVAL (10 * 60 * HZ) + +#define MC_DEFAULT_HASH_ENTRIES 256 +#define MC_HASH_SHIFT 8 +#define MC_HASH_SEGS ((sizeof(uint32_t) * 8) / MC_HASH_SHIFT) + +static struct kmem_cache *flow_cache; +struct kmem_cache *flow_stats_cache __read_mostly; + +static u16 range_n_bytes(const struct sw_flow_key_range *range) +{ + return range->end - range->start; +} + +void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src, + bool full, const struct sw_flow_mask *mask) +{ + int start = full ? 0 : mask->range.start; + int len = full ? sizeof *dst : range_n_bytes(&mask->range); + const long *m = (const long *)((const u8 *)&mask->key + start); + const long *s = (const long *)((const u8 *)src + start); + long *d = (long *)((u8 *)dst + start); + int i; + + /* If 'full' is true then all of 'dst' is fully initialized. Otherwise, + * if 'full' is false the memory outside of the 'mask->range' is left + * uninitialized. This can be used as an optimization when further + * operations on 'dst' only use contents within 'mask->range'. + */ + for (i = 0; i < len; i += sizeof(long)) + *d++ = *s++ & *m++; +} + +struct sw_flow *ovs_flow_alloc(void) +{ + struct sw_flow *flow; + struct sw_flow_stats *stats; + + flow = kmem_cache_zalloc(flow_cache, GFP_KERNEL); + if (!flow) + return ERR_PTR(-ENOMEM); + + flow->stats_last_writer = -1; + flow->cpu_used_mask = (struct cpumask *)&flow->stats[nr_cpu_ids]; + + /* Initialize the default stat node. */ + stats = kmem_cache_alloc_node(flow_stats_cache, + GFP_KERNEL | __GFP_ZERO, + node_online(0) ? 0 : NUMA_NO_NODE); + if (!stats) + goto err; + + spin_lock_init(&stats->lock); + + RCU_INIT_POINTER(flow->stats[0], stats); + + cpumask_set_cpu(0, flow->cpu_used_mask); + + return flow; +err: + kmem_cache_free(flow_cache, flow); + return ERR_PTR(-ENOMEM); +} + +int ovs_flow_tbl_count(const struct flow_table *table) +{ + return table->count; +} + +static void flow_free(struct sw_flow *flow) +{ + int cpu; + + if (ovs_identifier_is_key(&flow->id)) + kfree(flow->id.unmasked_key); + if (flow->sf_acts) + ovs_nla_free_flow_actions((struct sw_flow_actions __force *) + flow->sf_acts); + /* We open code this to make sure cpu 0 is always considered */ + for (cpu = 0; cpu < nr_cpu_ids; + cpu = cpumask_next(cpu, flow->cpu_used_mask)) { + if (flow->stats[cpu]) + kmem_cache_free(flow_stats_cache, + (struct sw_flow_stats __force *)flow->stats[cpu]); + } + + kmem_cache_free(flow_cache, flow); +} + +static void rcu_free_flow_callback(struct rcu_head *rcu) +{ + struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu); + + flow_free(flow); +} + +void ovs_flow_free(struct sw_flow *flow, bool deferred) +{ + if (!flow) + return; + + if (deferred) + call_rcu(&flow->rcu, rcu_free_flow_callback); + else + flow_free(flow); +} + +static void __table_instance_destroy(struct table_instance *ti) +{ + kvfree(ti->buckets); + kfree(ti); +} + +static struct table_instance *table_instance_alloc(int new_size) +{ + struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL); + int i; + + if (!ti) + return NULL; + + ti->buckets = kvmalloc_array(new_size, sizeof(struct hlist_head), + GFP_KERNEL); + if (!ti->buckets) { + kfree(ti); + return NULL; + } + + for (i = 0; i < new_size; i++) + INIT_HLIST_HEAD(&ti->buckets[i]); + + ti->n_buckets = new_size; + ti->node_ver = 0; + get_random_bytes(&ti->hash_seed, sizeof(u32)); + + return ti; +} + +static void __mask_array_destroy(struct mask_array *ma) +{ + free_percpu(ma->masks_usage_stats); + kfree(ma); +} + +static void mask_array_rcu_cb(struct rcu_head *rcu) +{ + struct mask_array *ma = container_of(rcu, struct mask_array, rcu); + + __mask_array_destroy(ma); +} + +static void tbl_mask_array_reset_counters(struct mask_array *ma) +{ + int i, cpu; + + /* As the per CPU counters are not atomic we can not go ahead and + * reset them from another CPU. To be able to still have an approximate + * zero based counter we store the value at reset, and subtract it + * later when processing. + */ + for (i = 0; i < ma->max; i++) { + ma->masks_usage_zero_cntr[i] = 0; + + for_each_possible_cpu(cpu) { + struct mask_array_stats *stats; + unsigned int start; + u64 counter; + + stats = per_cpu_ptr(ma->masks_usage_stats, cpu); + do { + start = u64_stats_fetch_begin(&stats->syncp); + counter = stats->usage_cntrs[i]; + } while (u64_stats_fetch_retry(&stats->syncp, start)); + + ma->masks_usage_zero_cntr[i] += counter; + } + } +} + +static struct mask_array *tbl_mask_array_alloc(int size) +{ + struct mask_array *new; + + size = max(MASK_ARRAY_SIZE_MIN, size); + new = kzalloc(sizeof(struct mask_array) + + sizeof(struct sw_flow_mask *) * size + + sizeof(u64) * size, GFP_KERNEL); + if (!new) + return NULL; + + new->masks_usage_zero_cntr = (u64 *)((u8 *)new + + sizeof(struct mask_array) + + sizeof(struct sw_flow_mask *) * + size); + + new->masks_usage_stats = __alloc_percpu(sizeof(struct mask_array_stats) + + sizeof(u64) * size, + __alignof__(u64)); + if (!new->masks_usage_stats) { + kfree(new); + return NULL; + } + + new->count = 0; + new->max = size; + + return new; +} + +static int tbl_mask_array_realloc(struct flow_table *tbl, int size) +{ + struct mask_array *old; + struct mask_array *new; + + new = tbl_mask_array_alloc(size); + if (!new) + return -ENOMEM; + + old = ovsl_dereference(tbl->mask_array); + if (old) { + int i; + + for (i = 0; i < old->max; i++) { + if (ovsl_dereference(old->masks[i])) + new->masks[new->count++] = old->masks[i]; + } + call_rcu(&old->rcu, mask_array_rcu_cb); + } + + rcu_assign_pointer(tbl->mask_array, new); + + return 0; +} + +static int tbl_mask_array_add_mask(struct flow_table *tbl, + struct sw_flow_mask *new) +{ + struct mask_array *ma = ovsl_dereference(tbl->mask_array); + int err, ma_count = READ_ONCE(ma->count); + + if (ma_count >= ma->max) { + err = tbl_mask_array_realloc(tbl, ma->max + + MASK_ARRAY_SIZE_MIN); + if (err) + return err; + + ma = ovsl_dereference(tbl->mask_array); + } else { + /* On every add or delete we need to reset the counters so + * every new mask gets a fair chance of being prioritized. + */ + tbl_mask_array_reset_counters(ma); + } + + BUG_ON(ovsl_dereference(ma->masks[ma_count])); + + rcu_assign_pointer(ma->masks[ma_count], new); + WRITE_ONCE(ma->count, ma_count + 1); + + return 0; +} + +static void tbl_mask_array_del_mask(struct flow_table *tbl, + struct sw_flow_mask *mask) +{ + struct mask_array *ma = ovsl_dereference(tbl->mask_array); + int i, ma_count = READ_ONCE(ma->count); + + /* Remove the deleted mask pointers from the array */ + for (i = 0; i < ma_count; i++) { + if (mask == ovsl_dereference(ma->masks[i])) + goto found; + } + + BUG(); + return; + +found: + WRITE_ONCE(ma->count, ma_count - 1); + + rcu_assign_pointer(ma->masks[i], ma->masks[ma_count - 1]); + RCU_INIT_POINTER(ma->masks[ma_count - 1], NULL); + + kfree_rcu(mask, rcu); + + /* Shrink the mask array if necessary. */ + if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) && + ma_count <= (ma->max / 3)) + tbl_mask_array_realloc(tbl, ma->max / 2); + else + tbl_mask_array_reset_counters(ma); + +} + +/* Remove 'mask' from the mask list, if it is not needed any more. */ +static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask) +{ + if (mask) { + /* ovs-lock is required to protect mask-refcount and + * mask list. + */ + ASSERT_OVSL(); + BUG_ON(!mask->ref_count); + mask->ref_count--; + + if (!mask->ref_count) + tbl_mask_array_del_mask(tbl, mask); + } +} + +static void __mask_cache_destroy(struct mask_cache *mc) +{ + free_percpu(mc->mask_cache); + kfree(mc); +} + +static void mask_cache_rcu_cb(struct rcu_head *rcu) +{ + struct mask_cache *mc = container_of(rcu, struct mask_cache, rcu); + + __mask_cache_destroy(mc); +} + +static struct mask_cache *tbl_mask_cache_alloc(u32 size) +{ + struct mask_cache_entry __percpu *cache = NULL; + struct mask_cache *new; + + /* Only allow size to be 0, or a power of 2, and does not exceed + * percpu allocation size. + */ + if ((!is_power_of_2(size) && size != 0) || + (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE) + return NULL; + + new = kzalloc(sizeof(*new), GFP_KERNEL); + if (!new) + return NULL; + + new->cache_size = size; + if (new->cache_size > 0) { + cache = __alloc_percpu(array_size(sizeof(struct mask_cache_entry), + new->cache_size), + __alignof__(struct mask_cache_entry)); + if (!cache) { + kfree(new); + return NULL; + } + } + + new->mask_cache = cache; + return new; +} +int ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size) +{ + struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache); + struct mask_cache *new; + + if (size == mc->cache_size) + return 0; + + if ((!is_power_of_2(size) && size != 0) || + (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE) + return -EINVAL; + + new = tbl_mask_cache_alloc(size); + if (!new) + return -ENOMEM; + + rcu_assign_pointer(table->mask_cache, new); + call_rcu(&mc->rcu, mask_cache_rcu_cb); + + return 0; +} + +int ovs_flow_tbl_init(struct flow_table *table) +{ + struct table_instance *ti, *ufid_ti; + struct mask_cache *mc; + struct mask_array *ma; + + mc = tbl_mask_cache_alloc(MC_DEFAULT_HASH_ENTRIES); + if (!mc) + return -ENOMEM; + + ma = tbl_mask_array_alloc(MASK_ARRAY_SIZE_MIN); + if (!ma) + goto free_mask_cache; + + ti = table_instance_alloc(TBL_MIN_BUCKETS); + if (!ti) + goto free_mask_array; + + ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS); + if (!ufid_ti) + goto free_ti; + + rcu_assign_pointer(table->ti, ti); + rcu_assign_pointer(table->ufid_ti, ufid_ti); + rcu_assign_pointer(table->mask_array, ma); + rcu_assign_pointer(table->mask_cache, mc); + table->last_rehash = jiffies; + table->count = 0; + table->ufid_count = 0; + return 0; + +free_ti: + __table_instance_destroy(ti); +free_mask_array: + __mask_array_destroy(ma); +free_mask_cache: + __mask_cache_destroy(mc); + return -ENOMEM; +} + +static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu) +{ + struct table_instance *ti; + + ti = container_of(rcu, struct table_instance, rcu); + __table_instance_destroy(ti); +} + +static void table_instance_flow_free(struct flow_table *table, + struct table_instance *ti, + struct table_instance *ufid_ti, + struct sw_flow *flow) +{ + hlist_del_rcu(&flow->flow_table.node[ti->node_ver]); + table->count--; + + if (ovs_identifier_is_ufid(&flow->id)) { + hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]); + table->ufid_count--; + } + + flow_mask_remove(table, flow->mask); +} + +/* Must be called with OVS mutex held. */ +void table_instance_flow_flush(struct flow_table *table, + struct table_instance *ti, + struct table_instance *ufid_ti) +{ + int i; + + for (i = 0; i < ti->n_buckets; i++) { + struct hlist_head *head = &ti->buckets[i]; + struct hlist_node *n; + struct sw_flow *flow; + + hlist_for_each_entry_safe(flow, n, head, + flow_table.node[ti->node_ver]) { + + table_instance_flow_free(table, ti, ufid_ti, + flow); + ovs_flow_free(flow, true); + } + } + + if (WARN_ON(table->count != 0 || + table->ufid_count != 0)) { + table->count = 0; + table->ufid_count = 0; + } +} + +static void table_instance_destroy(struct table_instance *ti, + struct table_instance *ufid_ti) +{ + call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); + call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb); +} + +/* No need for locking this function is called from RCU callback or + * error path. + */ +void ovs_flow_tbl_destroy(struct flow_table *table) +{ + struct table_instance *ti = rcu_dereference_raw(table->ti); + struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti); + struct mask_cache *mc = rcu_dereference_raw(table->mask_cache); + struct mask_array *ma = rcu_dereference_raw(table->mask_array); + + call_rcu(&mc->rcu, mask_cache_rcu_cb); + call_rcu(&ma->rcu, mask_array_rcu_cb); + table_instance_destroy(ti, ufid_ti); +} + +struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti, + u32 *bucket, u32 *last) +{ + struct sw_flow *flow; + struct hlist_head *head; + int ver; + int i; + + ver = ti->node_ver; + while (*bucket < ti->n_buckets) { + i = 0; + head = &ti->buckets[*bucket]; + hlist_for_each_entry_rcu(flow, head, flow_table.node[ver]) { + if (i < *last) { + i++; + continue; + } + *last = i + 1; + return flow; + } + (*bucket)++; + *last = 0; + } + + return NULL; +} + +static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash) +{ + hash = jhash_1word(hash, ti->hash_seed); + return &ti->buckets[hash & (ti->n_buckets - 1)]; +} + +static void table_instance_insert(struct table_instance *ti, + struct sw_flow *flow) +{ + struct hlist_head *head; + + head = find_bucket(ti, flow->flow_table.hash); + hlist_add_head_rcu(&flow->flow_table.node[ti->node_ver], head); +} + +static void ufid_table_instance_insert(struct table_instance *ti, + struct sw_flow *flow) +{ + struct hlist_head *head; + + head = find_bucket(ti, flow->ufid_table.hash); + hlist_add_head_rcu(&flow->ufid_table.node[ti->node_ver], head); +} + +static void flow_table_copy_flows(struct table_instance *old, + struct table_instance *new, bool ufid) +{ + int old_ver; + int i; + + old_ver = old->node_ver; + new->node_ver = !old_ver; + + /* Insert in new table. */ + for (i = 0; i < old->n_buckets; i++) { + struct sw_flow *flow; + struct hlist_head *head = &old->buckets[i]; + + if (ufid) + hlist_for_each_entry_rcu(flow, head, + ufid_table.node[old_ver], + lockdep_ovsl_is_held()) + ufid_table_instance_insert(new, flow); + else + hlist_for_each_entry_rcu(flow, head, + flow_table.node[old_ver], + lockdep_ovsl_is_held()) + table_instance_insert(new, flow); + } +} + +static struct table_instance *table_instance_rehash(struct table_instance *ti, + int n_buckets, bool ufid) +{ + struct table_instance *new_ti; + + new_ti = table_instance_alloc(n_buckets); + if (!new_ti) + return NULL; + + flow_table_copy_flows(ti, new_ti, ufid); + + return new_ti; +} + +int ovs_flow_tbl_flush(struct flow_table *flow_table) +{ + struct table_instance *old_ti, *new_ti; + struct table_instance *old_ufid_ti, *new_ufid_ti; + + new_ti = table_instance_alloc(TBL_MIN_BUCKETS); + if (!new_ti) + return -ENOMEM; + new_ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS); + if (!new_ufid_ti) + goto err_free_ti; + + old_ti = ovsl_dereference(flow_table->ti); + old_ufid_ti = ovsl_dereference(flow_table->ufid_ti); + + rcu_assign_pointer(flow_table->ti, new_ti); + rcu_assign_pointer(flow_table->ufid_ti, new_ufid_ti); + flow_table->last_rehash = jiffies; + + table_instance_flow_flush(flow_table, old_ti, old_ufid_ti); + table_instance_destroy(old_ti, old_ufid_ti); + return 0; + +err_free_ti: + __table_instance_destroy(new_ti); + return -ENOMEM; +} + +static u32 flow_hash(const struct sw_flow_key *key, + const struct sw_flow_key_range *range) +{ + const u32 *hash_key = (const u32 *)((const u8 *)key + range->start); + + /* Make sure number of hash bytes are multiple of u32. */ + int hash_u32s = range_n_bytes(range) >> 2; + + return jhash2(hash_key, hash_u32s, 0); +} + +static int flow_key_start(const struct sw_flow_key *key) +{ + if (key->tun_proto) + return 0; + else + return rounddown(offsetof(struct sw_flow_key, phy), + sizeof(long)); +} + +static bool cmp_key(const struct sw_flow_key *key1, + const struct sw_flow_key *key2, + int key_start, int key_end) +{ + const long *cp1 = (const long *)((const u8 *)key1 + key_start); + const long *cp2 = (const long *)((const u8 *)key2 + key_start); + int i; + + for (i = key_start; i < key_end; i += sizeof(long)) + if (*cp1++ ^ *cp2++) + return false; + + return true; +} + +static bool flow_cmp_masked_key(const struct sw_flow *flow, + const struct sw_flow_key *key, + const struct sw_flow_key_range *range) +{ + return cmp_key(&flow->key, key, range->start, range->end); +} + +static bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow, + const struct sw_flow_match *match) +{ + struct sw_flow_key *key = match->key; + int key_start = flow_key_start(key); + int key_end = match->range.end; + + BUG_ON(ovs_identifier_is_ufid(&flow->id)); + return cmp_key(flow->id.unmasked_key, key, key_start, key_end); +} + +static struct sw_flow *masked_flow_lookup(struct table_instance *ti, + const struct sw_flow_key *unmasked, + const struct sw_flow_mask *mask, + u32 *n_mask_hit) +{ + struct sw_flow *flow; + struct hlist_head *head; + u32 hash; + struct sw_flow_key masked_key; + + ovs_flow_mask_key(&masked_key, unmasked, false, mask); + hash = flow_hash(&masked_key, &mask->range); + head = find_bucket(ti, hash); + (*n_mask_hit)++; + + hlist_for_each_entry_rcu(flow, head, flow_table.node[ti->node_ver], + lockdep_ovsl_is_held()) { + if (flow->mask == mask && flow->flow_table.hash == hash && + flow_cmp_masked_key(flow, &masked_key, &mask->range)) + return flow; + } + return NULL; +} + +/* Flow lookup does full lookup on flow table. It starts with + * mask from index passed in *index. + * This function MUST be called with BH disabled due to the use + * of CPU specific variables. + */ +static struct sw_flow *flow_lookup(struct flow_table *tbl, + struct table_instance *ti, + struct mask_array *ma, + const struct sw_flow_key *key, + u32 *n_mask_hit, + u32 *n_cache_hit, + u32 *index) +{ + struct mask_array_stats *stats = this_cpu_ptr(ma->masks_usage_stats); + struct sw_flow *flow; + struct sw_flow_mask *mask; + int i; + + if (likely(*index < ma->max)) { + mask = rcu_dereference_ovsl(ma->masks[*index]); + if (mask) { + flow = masked_flow_lookup(ti, key, mask, n_mask_hit); + if (flow) { + u64_stats_update_begin(&stats->syncp); + stats->usage_cntrs[*index]++; + u64_stats_update_end(&stats->syncp); + (*n_cache_hit)++; + return flow; + } + } + } + + for (i = 0; i < ma->max; i++) { + + if (i == *index) + continue; + + mask = rcu_dereference_ovsl(ma->masks[i]); + if (unlikely(!mask)) + break; + + flow = masked_flow_lookup(ti, key, mask, n_mask_hit); + if (flow) { /* Found */ + *index = i; + u64_stats_update_begin(&stats->syncp); + stats->usage_cntrs[*index]++; + u64_stats_update_end(&stats->syncp); + return flow; + } + } + + return NULL; +} + +/* + * mask_cache maps flow to probable mask. This cache is not tightly + * coupled cache, It means updates to mask list can result in inconsistent + * cache entry in mask cache. + * This is per cpu cache and is divided in MC_HASH_SEGS segments. + * In case of a hash collision the entry is hashed in next segment. + * */ +struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl, + const struct sw_flow_key *key, + u32 skb_hash, + u32 *n_mask_hit, + u32 *n_cache_hit) +{ + struct mask_cache *mc = rcu_dereference(tbl->mask_cache); + struct mask_array *ma = rcu_dereference(tbl->mask_array); + struct table_instance *ti = rcu_dereference(tbl->ti); + struct mask_cache_entry *entries, *ce; + struct sw_flow *flow; + u32 hash; + int seg; + + *n_mask_hit = 0; + *n_cache_hit = 0; + if (unlikely(!skb_hash || mc->cache_size == 0)) { + u32 mask_index = 0; + u32 cache = 0; + + return flow_lookup(tbl, ti, ma, key, n_mask_hit, &cache, + &mask_index); + } + + /* Pre and post recirulation flows usually have the same skb_hash + * value. To avoid hash collisions, rehash the 'skb_hash' with + * 'recirc_id'. */ + if (key->recirc_id) + skb_hash = jhash_1word(skb_hash, key->recirc_id); + + ce = NULL; + hash = skb_hash; + entries = this_cpu_ptr(mc->mask_cache); + + /* Find the cache entry 'ce' to operate on. */ + for (seg = 0; seg < MC_HASH_SEGS; seg++) { + int index = hash & (mc->cache_size - 1); + struct mask_cache_entry *e; + + e = &entries[index]; + if (e->skb_hash == skb_hash) { + flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, + n_cache_hit, &e->mask_index); + if (!flow) + e->skb_hash = 0; + return flow; + } + + if (!ce || e->skb_hash < ce->skb_hash) + ce = e; /* A better replacement cache candidate. */ + + hash >>= MC_HASH_SHIFT; + } + + /* Cache miss, do full lookup. */ + flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, n_cache_hit, + &ce->mask_index); + if (flow) + ce->skb_hash = skb_hash; + + *n_cache_hit = 0; + return flow; +} + +struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl, + const struct sw_flow_key *key) +{ + struct table_instance *ti = rcu_dereference_ovsl(tbl->ti); + struct mask_array *ma = rcu_dereference_ovsl(tbl->mask_array); + u32 __always_unused n_mask_hit; + u32 __always_unused n_cache_hit; + struct sw_flow *flow; + u32 index = 0; + + /* This function gets called trough the netlink interface and therefore + * is preemptible. However, flow_lookup() function needs to be called + * with BH disabled due to CPU specific variables. + */ + local_bh_disable(); + flow = flow_lookup(tbl, ti, ma, key, &n_mask_hit, &n_cache_hit, &index); + local_bh_enable(); + return flow; +} + +struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl, + const struct sw_flow_match *match) +{ + struct mask_array *ma = ovsl_dereference(tbl->mask_array); + int i; + + /* Always called under ovs-mutex. */ + for (i = 0; i < ma->max; i++) { + struct table_instance *ti = rcu_dereference_ovsl(tbl->ti); + u32 __always_unused n_mask_hit; + struct sw_flow_mask *mask; + struct sw_flow *flow; + + mask = ovsl_dereference(ma->masks[i]); + if (!mask) + continue; + + flow = masked_flow_lookup(ti, match->key, mask, &n_mask_hit); + if (flow && ovs_identifier_is_key(&flow->id) && + ovs_flow_cmp_unmasked_key(flow, match)) { + return flow; + } + } + + return NULL; +} + +static u32 ufid_hash(const struct sw_flow_id *sfid) +{ + return jhash(sfid->ufid, sfid->ufid_len, 0); +} + +static bool ovs_flow_cmp_ufid(const struct sw_flow *flow, + const struct sw_flow_id *sfid) +{ + if (flow->id.ufid_len != sfid->ufid_len) + return false; + + return !memcmp(flow->id.ufid, sfid->ufid, sfid->ufid_len); +} + +bool ovs_flow_cmp(const struct sw_flow *flow, + const struct sw_flow_match *match) +{ + if (ovs_identifier_is_ufid(&flow->id)) + return flow_cmp_masked_key(flow, match->key, &match->range); + + return ovs_flow_cmp_unmasked_key(flow, match); +} + +struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl, + const struct sw_flow_id *ufid) +{ + struct table_instance *ti = rcu_dereference_ovsl(tbl->ufid_ti); + struct sw_flow *flow; + struct hlist_head *head; + u32 hash; + + hash = ufid_hash(ufid); + head = find_bucket(ti, hash); + hlist_for_each_entry_rcu(flow, head, ufid_table.node[ti->node_ver], + lockdep_ovsl_is_held()) { + if (flow->ufid_table.hash == hash && + ovs_flow_cmp_ufid(flow, ufid)) + return flow; + } + return NULL; +} + +int ovs_flow_tbl_num_masks(const struct flow_table *table) +{ + struct mask_array *ma = rcu_dereference_ovsl(table->mask_array); + return READ_ONCE(ma->count); +} + +u32 ovs_flow_tbl_masks_cache_size(const struct flow_table *table) +{ + struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache); + + return READ_ONCE(mc->cache_size); +} + +static struct table_instance *table_instance_expand(struct table_instance *ti, + bool ufid) +{ + return table_instance_rehash(ti, ti->n_buckets * 2, ufid); +} + +/* Must be called with OVS mutex held. */ +void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow) +{ + struct table_instance *ti = ovsl_dereference(table->ti); + struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti); + + BUG_ON(table->count == 0); + table_instance_flow_free(table, ti, ufid_ti, flow); +} + +static struct sw_flow_mask *mask_alloc(void) +{ + struct sw_flow_mask *mask; + + mask = kmalloc(sizeof(*mask), GFP_KERNEL); + if (mask) + mask->ref_count = 1; + + return mask; +} + +static bool mask_equal(const struct sw_flow_mask *a, + const struct sw_flow_mask *b) +{ + const u8 *a_ = (const u8 *)&a->key + a->range.start; + const u8 *b_ = (const u8 *)&b->key + b->range.start; + + return (a->range.end == b->range.end) + && (a->range.start == b->range.start) + && (memcmp(a_, b_, range_n_bytes(&a->range)) == 0); +} + +static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl, + const struct sw_flow_mask *mask) +{ + struct mask_array *ma; + int i; + + ma = ovsl_dereference(tbl->mask_array); + for (i = 0; i < ma->max; i++) { + struct sw_flow_mask *t; + t = ovsl_dereference(ma->masks[i]); + + if (t && mask_equal(mask, t)) + return t; + } + + return NULL; +} + +/* Add 'mask' into the mask list, if it is not already there. */ +static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow, + const struct sw_flow_mask *new) +{ + struct sw_flow_mask *mask; + + mask = flow_mask_find(tbl, new); + if (!mask) { + /* Allocate a new mask if none exists. */ + mask = mask_alloc(); + if (!mask) + return -ENOMEM; + mask->key = new->key; + mask->range = new->range; + + /* Add mask to mask-list. */ + if (tbl_mask_array_add_mask(tbl, mask)) { + kfree(mask); + return -ENOMEM; + } + } else { + BUG_ON(!mask->ref_count); + mask->ref_count++; + } + + flow->mask = mask; + return 0; +} + +/* Must be called with OVS mutex held. */ +static void flow_key_insert(struct flow_table *table, struct sw_flow *flow) +{ + struct table_instance *new_ti = NULL; + struct table_instance *ti; + + flow->flow_table.hash = flow_hash(&flow->key, &flow->mask->range); + ti = ovsl_dereference(table->ti); + table_instance_insert(ti, flow); + table->count++; + + /* Expand table, if necessary, to make room. */ + if (table->count > ti->n_buckets) + new_ti = table_instance_expand(ti, false); + else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL)) + new_ti = table_instance_rehash(ti, ti->n_buckets, false); + + if (new_ti) { + rcu_assign_pointer(table->ti, new_ti); + call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); + table->last_rehash = jiffies; + } +} + +/* Must be called with OVS mutex held. */ +static void flow_ufid_insert(struct flow_table *table, struct sw_flow *flow) +{ + struct table_instance *ti; + + flow->ufid_table.hash = ufid_hash(&flow->id); + ti = ovsl_dereference(table->ufid_ti); + ufid_table_instance_insert(ti, flow); + table->ufid_count++; + + /* Expand table, if necessary, to make room. */ + if (table->ufid_count > ti->n_buckets) { + struct table_instance *new_ti; + + new_ti = table_instance_expand(ti, true); + if (new_ti) { + rcu_assign_pointer(table->ufid_ti, new_ti); + call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); + } + } +} + +/* Must be called with OVS mutex held. */ +int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow, + const struct sw_flow_mask *mask) +{ + int err; + + err = flow_mask_insert(table, flow, mask); + if (err) + return err; + flow_key_insert(table, flow); + if (ovs_identifier_is_ufid(&flow->id)) + flow_ufid_insert(table, flow); + + return 0; +} + +static int compare_mask_and_count(const void *a, const void *b) +{ + const struct mask_count *mc_a = a; + const struct mask_count *mc_b = b; + + return (s64)mc_b->counter - (s64)mc_a->counter; +} + +/* Must be called with OVS mutex held. */ +void ovs_flow_masks_rebalance(struct flow_table *table) +{ + struct mask_array *ma = rcu_dereference_ovsl(table->mask_array); + struct mask_count *masks_and_count; + struct mask_array *new; + int masks_entries = 0; + int i; + + /* Build array of all current entries with use counters. */ + masks_and_count = kmalloc_array(ma->max, sizeof(*masks_and_count), + GFP_KERNEL); + if (!masks_and_count) + return; + + for (i = 0; i < ma->max; i++) { + struct sw_flow_mask *mask; + int cpu; + + mask = rcu_dereference_ovsl(ma->masks[i]); + if (unlikely(!mask)) + break; + + masks_and_count[i].index = i; + masks_and_count[i].counter = 0; + + for_each_possible_cpu(cpu) { + struct mask_array_stats *stats; + unsigned int start; + u64 counter; + + stats = per_cpu_ptr(ma->masks_usage_stats, cpu); + do { + start = u64_stats_fetch_begin(&stats->syncp); + counter = stats->usage_cntrs[i]; + } while (u64_stats_fetch_retry(&stats->syncp, start)); + + masks_and_count[i].counter += counter; + } + + /* Subtract the zero count value. */ + masks_and_count[i].counter -= ma->masks_usage_zero_cntr[i]; + + /* Rather than calling tbl_mask_array_reset_counters() + * below when no change is needed, do it inline here. + */ + ma->masks_usage_zero_cntr[i] += masks_and_count[i].counter; + } + + if (i == 0) + goto free_mask_entries; + + /* Sort the entries */ + masks_entries = i; + sort(masks_and_count, masks_entries, sizeof(*masks_and_count), + compare_mask_and_count, NULL); + + /* If the order is the same, nothing to do... */ + for (i = 0; i < masks_entries; i++) { + if (i != masks_and_count[i].index) + break; + } + if (i == masks_entries) + goto free_mask_entries; + + /* Rebuilt the new list in order of usage. */ + new = tbl_mask_array_alloc(ma->max); + if (!new) + goto free_mask_entries; + + for (i = 0; i < masks_entries; i++) { + int index = masks_and_count[i].index; + + if (ovsl_dereference(ma->masks[index])) + new->masks[new->count++] = ma->masks[index]; + } + + rcu_assign_pointer(table->mask_array, new); + call_rcu(&ma->rcu, mask_array_rcu_cb); + +free_mask_entries: + kfree(masks_and_count); +} + +/* Initializes the flow module. + * Returns zero if successful or a negative error code. */ +int ovs_flow_init(void) +{ + BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long)); + BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long)); + + flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow) + + (nr_cpu_ids + * sizeof(struct sw_flow_stats *)) + + cpumask_size(), + 0, 0, NULL); + if (flow_cache == NULL) + return -ENOMEM; + + flow_stats_cache + = kmem_cache_create("sw_flow_stats", sizeof(struct sw_flow_stats), + 0, SLAB_HWCACHE_ALIGN, NULL); + if (flow_stats_cache == NULL) { + kmem_cache_destroy(flow_cache); + flow_cache = NULL; + return -ENOMEM; + } + + return 0; +} + +/* Uninitializes the flow module. */ +void ovs_flow_exit(void) +{ + kmem_cache_destroy(flow_stats_cache); + kmem_cache_destroy(flow_cache); +} |