linux/net/openvswitch/flow_table.c

651 lines
15 KiB
C

/*
* Copyright (c) 2007-2014 Nicira, Inc.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*/
#include "flow.h"
#include "datapath.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/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 <net/ip.h>
#include <net/ipv6.h>
#include <net/ndisc.h>
#define TBL_MIN_BUCKETS 1024
#define REHASH_INTERVAL (10 * 60 * HZ)
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,
const struct sw_flow_mask *mask)
{
const long *m = (const long *)((const u8 *)&mask->key +
mask->range.start);
const long *s = (const long *)((const u8 *)src +
mask->range.start);
long *d = (long *)((u8 *)dst + mask->range.start);
int i;
/* The memory outside of the 'mask->range' are not set since
* further operations on 'dst' only uses contents within
* 'mask->range'.
*/
for (i = 0; i < range_n_bytes(&mask->range); i += sizeof(long))
*d++ = *s++ & *m++;
}
struct sw_flow *ovs_flow_alloc(void)
{
struct sw_flow *flow;
struct flow_stats *stats;
int node;
flow = kmem_cache_alloc(flow_cache, GFP_KERNEL);
if (!flow)
return ERR_PTR(-ENOMEM);
flow->sf_acts = NULL;
flow->mask = NULL;
flow->stats_last_writer = NUMA_NO_NODE;
/* Initialize the default stat node. */
stats = kmem_cache_alloc_node(flow_stats_cache,
GFP_KERNEL | __GFP_ZERO, 0);
if (!stats)
goto err;
spin_lock_init(&stats->lock);
RCU_INIT_POINTER(flow->stats[0], stats);
for_each_node(node)
if (node != 0)
RCU_INIT_POINTER(flow->stats[node], NULL);
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 struct flex_array *alloc_buckets(unsigned int n_buckets)
{
struct flex_array *buckets;
int i, err;
buckets = flex_array_alloc(sizeof(struct hlist_head),
n_buckets, GFP_KERNEL);
if (!buckets)
return NULL;
err = flex_array_prealloc(buckets, 0, n_buckets, GFP_KERNEL);
if (err) {
flex_array_free(buckets);
return NULL;
}
for (i = 0; i < n_buckets; i++)
INIT_HLIST_HEAD((struct hlist_head *)
flex_array_get(buckets, i));
return buckets;
}
static void flow_free(struct sw_flow *flow)
{
int node;
kfree((struct sw_flow_actions __force *)flow->sf_acts);
for_each_node(node)
if (flow->stats[node])
kmem_cache_free(flow_stats_cache,
(struct flow_stats __force *)flow->stats[node]);
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 free_buckets(struct flex_array *buckets)
{
flex_array_free(buckets);
}
static void __table_instance_destroy(struct table_instance *ti)
{
free_buckets(ti->buckets);
kfree(ti);
}
static struct table_instance *table_instance_alloc(int new_size)
{
struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL);
if (!ti)
return NULL;
ti->buckets = alloc_buckets(new_size);
if (!ti->buckets) {
kfree(ti);
return NULL;
}
ti->n_buckets = new_size;
ti->node_ver = 0;
ti->keep_flows = false;
get_random_bytes(&ti->hash_seed, sizeof(u32));
return ti;
}
int ovs_flow_tbl_init(struct flow_table *table)
{
struct table_instance *ti;
ti = table_instance_alloc(TBL_MIN_BUCKETS);
if (!ti)
return -ENOMEM;
rcu_assign_pointer(table->ti, ti);
INIT_LIST_HEAD(&table->mask_list);
table->last_rehash = jiffies;
table->count = 0;
return 0;
}
static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
{
struct table_instance *ti = container_of(rcu, struct table_instance, rcu);
__table_instance_destroy(ti);
}
static void table_instance_destroy(struct table_instance *ti, bool deferred)
{
int i;
if (!ti)
return;
if (ti->keep_flows)
goto skip_flows;
for (i = 0; i < ti->n_buckets; i++) {
struct sw_flow *flow;
struct hlist_head *head = flex_array_get(ti->buckets, i);
struct hlist_node *n;
int ver = ti->node_ver;
hlist_for_each_entry_safe(flow, n, head, hash_node[ver]) {
hlist_del_rcu(&flow->hash_node[ver]);
ovs_flow_free(flow, deferred);
}
}
skip_flows:
if (deferred)
call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
else
__table_instance_destroy(ti);
}
/* 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);
table_instance_destroy(ti, false);
}
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 = flex_array_get(ti->buckets, *bucket);
hlist_for_each_entry_rcu(flow, head, hash_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 flex_array_get(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->hash);
hlist_add_head_rcu(&flow->hash_node[ti->node_ver], head);
}
static void flow_table_copy_flows(struct table_instance *old,
struct table_instance *new)
{
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;
head = flex_array_get(old->buckets, i);
hlist_for_each_entry(flow, head, hash_node[old_ver])
table_instance_insert(new, flow);
}
old->keep_flows = true;
}
static struct table_instance *table_instance_rehash(struct table_instance *ti,
int n_buckets)
{
struct table_instance *new_ti;
new_ti = table_instance_alloc(n_buckets);
if (!new_ti)
return NULL;
flow_table_copy_flows(ti, new_ti);
return new_ti;
}
int ovs_flow_tbl_flush(struct flow_table *flow_table)
{
struct table_instance *old_ti;
struct table_instance *new_ti;
old_ti = ovsl_dereference(flow_table->ti);
new_ti = table_instance_alloc(TBL_MIN_BUCKETS);
if (!new_ti)
return -ENOMEM;
rcu_assign_pointer(flow_table->ti, new_ti);
flow_table->last_rehash = jiffies;
flow_table->count = 0;
table_instance_destroy(old_ti, true);
return 0;
}
static u32 flow_hash(const struct sw_flow_key *key, int key_start,
int key_end)
{
const u32 *hash_key = (const u32 *)((const u8 *)key + key_start);
int hash_u32s = (key_end - key_start) >> 2;
/* Make sure number of hash bytes are multiple of u32. */
BUILD_BUG_ON(sizeof(long) % sizeof(u32));
return jhash2(hash_key, hash_u32s, 0);
}
static int flow_key_start(const struct sw_flow_key *key)
{
if (key->tun_key.ipv4_dst)
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);
long diffs = 0;
int i;
for (i = key_start; i < key_end; i += sizeof(long))
diffs |= *cp1++ ^ *cp2++;
return diffs == 0;
}
static bool flow_cmp_masked_key(const struct sw_flow *flow,
const struct sw_flow_key *key,
int key_start, int key_end)
{
return cmp_key(&flow->key, key, key_start, key_end);
}
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;
return cmp_key(&flow->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)
{
struct sw_flow *flow;
struct hlist_head *head;
int key_start = mask->range.start;
int key_end = mask->range.end;
u32 hash;
struct sw_flow_key masked_key;
ovs_flow_mask_key(&masked_key, unmasked, mask);
hash = flow_hash(&masked_key, key_start, key_end);
head = find_bucket(ti, hash);
hlist_for_each_entry_rcu(flow, head, hash_node[ti->node_ver]) {
if (flow->mask == mask && flow->hash == hash &&
flow_cmp_masked_key(flow, &masked_key,
key_start, key_end))
return flow;
}
return NULL;
}
struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
const struct sw_flow_key *key,
u32 *n_mask_hit)
{
struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
struct sw_flow_mask *mask;
struct sw_flow *flow;
*n_mask_hit = 0;
list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
(*n_mask_hit)++;
flow = masked_flow_lookup(ti, key, mask);
if (flow) /* Found */
return flow;
}
return NULL;
}
struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
const struct sw_flow_key *key)
{
u32 __always_unused n_mask_hit;
return ovs_flow_tbl_lookup_stats(tbl, key, &n_mask_hit);
}
struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
const struct sw_flow_match *match)
{
struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
struct sw_flow_mask *mask;
struct sw_flow *flow;
/* Always called under ovs-mutex. */
list_for_each_entry(mask, &tbl->mask_list, list) {
flow = masked_flow_lookup(ti, match->key, mask);
if (flow && ovs_flow_cmp_unmasked_key(flow, match)) /* Found */
return flow;
}
return NULL;
}
int ovs_flow_tbl_num_masks(const struct flow_table *table)
{
struct sw_flow_mask *mask;
int num = 0;
list_for_each_entry(mask, &table->mask_list, list)
num++;
return num;
}
static struct table_instance *table_instance_expand(struct table_instance *ti)
{
return table_instance_rehash(ti, ti->n_buckets * 2);
}
/* 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) {
list_del_rcu(&mask->list);
kfree_rcu(mask, rcu);
}
}
}
/* 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);
BUG_ON(table->count == 0);
hlist_del_rcu(&flow->hash_node[ti->node_ver]);
table->count--;
/* RCU delete the mask. 'flow->mask' is not NULLed, as it should be
* accessible as long as the RCU read lock is held.
*/
flow_mask_remove(table, flow->mask);
}
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 list_head *ml;
list_for_each(ml, &tbl->mask_list) {
struct sw_flow_mask *m;
m = container_of(ml, struct sw_flow_mask, list);
if (mask_equal(mask, m))
return m;
}
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 exsits. */
mask = mask_alloc();
if (!mask)
return -ENOMEM;
mask->key = new->key;
mask->range = new->range;
list_add_rcu(&mask->list, &tbl->mask_list);
} else {
BUG_ON(!mask->ref_count);
mask->ref_count++;
}
flow->mask = mask;
return 0;
}
/* 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)
{
struct table_instance *new_ti = NULL;
struct table_instance *ti;
int err;
err = flow_mask_insert(table, flow, mask);
if (err)
return err;
flow->hash = flow_hash(&flow->key, flow->mask->range.start,
flow->mask->range.end);
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);
else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL))
new_ti = table_instance_rehash(ti, ti->n_buckets);
if (new_ti) {
rcu_assign_pointer(table->ti, new_ti);
table_instance_destroy(ti, true);
table->last_rehash = jiffies;
}
return 0;
}
/* 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)
+ (num_possible_nodes()
* sizeof(struct flow_stats *)),
0, 0, NULL);
if (flow_cache == NULL)
return -ENOMEM;
flow_stats_cache
= kmem_cache_create("sw_flow_stats", sizeof(struct 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);
}