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Date: Tue, 20 Jan 2015 12:27:28 -0800
From: John Fastabend <john.fastabend@...il.com>
To: tgraf@...g.ch, simon.horman@...ronome.com, sfeldma@...il.com
Cc: netdev@...r.kernel.org, jhs@...atatu.com, davem@...emloft.net,
gerlitz.or@...il.com, andy@...yhouse.net, ast@...mgrid.com
Subject: [net-next PATCH v3 03/12] net: flow: implement flow cache for get
routines
I used rhashtable to implement a flow cache so software can track the
currently programmed rules without requiring every driver to
implement its own cache logic or fetch information from hardware.
I chose rhashtable to get the dynamic resizing.
Signed-off-by: John Fastabend <john.r.fastabend@...el.com>
---
include/linux/if_flow.h | 24 +++++++
net/core/flow_table.c | 152 +++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 169 insertions(+), 7 deletions(-)
diff --git a/include/linux/if_flow.h b/include/linux/if_flow.h
index 712b54f..07d7bca 100644
--- a/include/linux/if_flow.h
+++ b/include/linux/if_flow.h
@@ -21,6 +21,7 @@
#define _IF_FLOW_H
#include <uapi/linux/if_flow.h>
+#include <linux/rhashtable.h>
/**
* @struct net_flow_fields
@@ -134,6 +135,7 @@ struct net_flow_field_ref {
* @size max number of entries for table or -1 for unbounded
* @matches null terminated set of supported match types given by match uid
* @actions null terminated set of supported action types given by action uid
+ * @cache software cache of hardware flows
*/
struct net_flow_tbl {
char *name;
@@ -143,6 +145,7 @@ struct net_flow_tbl {
__u32 size;
struct net_flow_field_ref *matches;
__u32 *actions;
+ struct rhashtable cache;
};
/**
@@ -190,6 +193,8 @@ struct net_flow_tbl_node {
* @struct net_flow_rule
* @brief describes the match/action entry
*
+ * @node node for resizable hash table used for software cache of rules
+ * @rcu used to support delayed freeing via call_rcu in software cache
* @uid unique identifier for flow
* @priority priority to execute flow match/action in table
* @match null terminated set of match uids match criteria
@@ -198,10 +203,29 @@ struct net_flow_tbl_node {
* Flows must match all entries in match set.
*/
struct net_flow_rule {
+ struct rhash_head node;
+ struct rcu_head rcu;
__u32 table_id;
__u32 uid;
__u32 priority;
struct net_flow_field_ref *matches;
struct net_flow_action *actions;
};
+
+#ifdef CONFIG_NET_FLOW_TABLES
+int net_flow_init_cache(struct net_flow_tbl *table);
+void net_flow_destroy_cache(struct net_flow_tbl *table);
+#else
+static inline int
+net_flow_init_cache(struct net_flow_tbl *table)
+{
+ return 0;
+}
+
+static inline void
+net_flow_destroy_cache(struct net_flow_tbl *table)
+{
+ return;
+}
+#endif /* CONFIG_NET_FLOW_TABLES */
#endif /* _IF_FLOW_H_ */
diff --git a/net/core/flow_table.c b/net/core/flow_table.c
index 7b85e53..c1a9716 100644
--- a/net/core/flow_table.c
+++ b/net/core/flow_table.c
@@ -26,6 +26,8 @@
#include <net/genetlink.h>
#include <net/rtnetlink.h>
#include <linux/module.h>
+#include <linux/rhashtable.h>
+#include <linux/jhash.h>
static DEFINE_MUTEX(net_flow_mutex);
@@ -919,6 +921,27 @@ static int net_flow_cmd_get_table_graph(struct sk_buff *skb,
return genlmsg_reply(msg, info);
}
+static struct net_flow_tbl *net_flow_get_table(struct net_device *dev,
+ int table_id)
+{
+ struct net_flow_tbl **tables;
+ int i;
+
+ if (!dev->netdev_ops->ndo_flow_get_tbls)
+ return NULL;
+
+ tables = dev->netdev_ops->ndo_flow_get_tbls(dev);
+ if (!tables)
+ return NULL;
+
+ for (i = 0; tables[i]; i++) {
+ if (tables[i]->uid == table_id)
+ return tables[i];
+ }
+
+ return NULL;
+}
+
static int net_flow_put_flow_action(struct sk_buff *skb,
struct net_flow_action *a)
{
@@ -1017,11 +1040,39 @@ put_failure:
return err;
}
+static int net_flow_get_rule_cache(struct sk_buff *skb,
+ struct net_flow_tbl *table,
+ int min, int max)
+{
+ const struct bucket_table *tbl;
+ struct net_flow_rule *he;
+ int i, err = 0;
+
+ rcu_read_lock();
+ tbl = rht_dereference_rcu(table->cache.tbl, &table->cache);
+
+ for (i = 0; i < tbl->size; i++) {
+ struct rhash_head *pos;
+
+ rht_for_each_entry_rcu(he, pos, tbl, i, node) {
+ if (he->uid < min || (max > 0 && he->uid > max))
+ continue;
+ err = net_flow_put_rule(skb, he);
+ if (err)
+ goto out;
+ }
+ }
+out:
+ rcu_read_unlock();
+ return err;
+}
+
static struct sk_buff *net_flow_build_flows_msg(struct net_device *dev,
u32 portid, int seq, u8 cmd,
int min, int max, int table)
{
struct genlmsghdr *hdr;
+ struct net_flow_tbl *t;
struct nlattr *flows;
struct sk_buff *skb;
int err = -ENOBUFS;
@@ -1042,15 +1093,23 @@ static struct sk_buff *net_flow_build_flows_msg(struct net_device *dev,
goto out;
}
+ t = net_flow_get_table(dev, table);
+ if (!t) {
+ err = -EINVAL;
+ goto out;
+ }
+
flows = nla_nest_start(skb, NFL_FLOWS);
if (!flows) {
err = -EMSGSIZE;
goto out;
}
- err = -EOPNOTSUPP;
- if (err < 0)
- goto out_cancel;
+ err = net_flow_get_rule_cache(skb, t, min, max);
+ if (err < 0) {
+ nla_nest_cancel(skb, flows);
+ goto out;
+ }
nla_nest_end(skb, flows);
@@ -1059,8 +1118,6 @@ static struct sk_buff *net_flow_build_flows_msg(struct net_device *dev,
goto out;
return skb;
-out_cancel:
- nla_nest_cancel(skb, flows);
out:
nlmsg_free(skb);
return ERR_PTR(err);
@@ -1300,6 +1357,13 @@ static void net_flow_rule_free(struct net_flow_rule *rule)
kfree(rule);
}
+static void net_flow_rule_free_rcu(struct rcu_head *head)
+{
+ struct net_flow_rule *r = container_of(head, struct net_flow_rule, rcu);
+
+ net_flow_rule_free(r);
+}
+
static const
struct nla_policy net_flow_actarg_policy[NFL_ACTION_ARG_MAX + 1] = {
[NFL_ACTION_ARG_NAME] = { .type = NLA_STRING },
@@ -1505,6 +1569,70 @@ static int net_flow_get_rule(struct net_flow_rule *rule, struct nlattr *attr)
return 0;
}
+#define NFL_TABLE_ELEM_HINT 10
+int net_flow_init_cache(struct net_flow_tbl *table)
+{
+ struct rhashtable_params params = {
+ .nelem_hint = NFL_TABLE_ELEM_HINT,
+ .head_offset = offsetof(struct net_flow_rule, node),
+ .key_offset = offsetof(struct net_flow_rule, uid),
+ .key_len = sizeof(__u32),
+ .hashfn = jhash,
+ .grow_decision = rht_grow_above_75,
+ .shrink_decision = rht_shrink_below_30
+ };
+
+ return rhashtable_init(&table->cache, ¶ms);
+}
+EXPORT_SYMBOL(net_flow_init_cache);
+
+void net_flow_destroy_cache(struct net_flow_tbl *table)
+{
+ struct rhashtable *cache = &table->cache;
+ const struct bucket_table *tbl;
+ struct net_flow_rule *he;
+ struct rhash_head *pos, *next;
+ unsigned int i;
+
+ /* Stop an eventual async resizing */
+ cache->being_destroyed = true;
+ mutex_lock(&cache->mutex);
+
+ tbl = rht_dereference(cache->tbl, cache);
+ for (i = 0; i < tbl->size; i++) {
+ rht_for_each_entry_safe(he, pos, next, tbl, i, node) {
+ rhashtable_remove(&table->cache, &he->node);
+ call_rcu(&he->rcu, net_flow_rule_free_rcu);
+ }
+ }
+
+ mutex_unlock(&cache->mutex);
+ rhashtable_destroy(cache);
+}
+EXPORT_SYMBOL(net_flow_destroy_cache);
+
+static void net_flow_add_rule_cache(struct net_flow_tbl *table,
+ struct net_flow_rule *this)
+{
+ rhashtable_insert(&table->cache, &this->node);
+}
+
+static int net_flow_del_rule_cache(struct net_flow_tbl *table,
+ struct net_flow_rule *this)
+{
+ struct net_flow_rule *he;
+
+ he = rhashtable_lookup(&table->cache, &this->uid);
+ if (he) {
+ rhashtable_remove(&table->cache, &he->node);
+ synchronize_rcu();
+ net_flow_rule_free(he);
+ return 0;
+ }
+
+ return -EEXIST;
+}
+
static int net_flow_table_cmd_flows(struct sk_buff *recv_skb,
struct genl_info *info)
{
@@ -1546,6 +1674,8 @@ static int net_flow_table_cmd_flows(struct sk_buff *recv_skb,
net_flow_lock();
nla_for_each_nested(flow, info->attrs[NFL_FLOWS], rem) {
+ struct net_flow_tbl *table;
+
if (nla_type(flow) != NFL_FLOW)
continue;
@@ -1563,12 +1693,22 @@ static int net_flow_table_cmd_flows(struct sk_buff *recv_skb,
if (err)
goto out_locked;
+ table = net_flow_get_table(dev, this->table_id);
+ if (!table) {
+ err = -EINVAL;
+ goto skip;
+ }
+
switch (cmd) {
case NFL_TABLE_CMD_SET_FLOWS:
err = dev->netdev_ops->ndo_flow_set_rule(dev, this);
+ if (!err)
+ net_flow_add_rule_cache(table, this);
break;
case NFL_TABLE_CMD_DEL_FLOWS:
err = dev->netdev_ops->ndo_flow_del_rule(dev, this);
+ if (!err)
+ err = net_flow_del_rule_cache(table, this);
break;
default:
err = -EOPNOTSUPP;
@@ -1597,8 +1737,6 @@ skip:
net_flow_put_rule(skb, this);
}
- net_flow_rule_free(this);
-
if (err && err_handle == NFL_FLOWS_ERROR_ABORT)
goto out_locked;
}
--
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