openvswitch: Add recirc and hash action.
Recirc action allows a packet to reenter openvswitch processing.
currently openvswitch lookup flow for packet received and execute
set of actions on that packet, with help of recirc action we can
process/modify the packet and recirculate it back in openvswitch
for another pass.
OVS hash action calculates 5-tupple hash and set hash in flow-key
hash. This can be used along with recirculation for distributing
packets among different ports for bond devices.
For example:
OVS bonding can use following actions:
Match on: bond flow; Action: hash, recirc(id)
Match on: recirc-id == id and hash lower bits == a;
Action: output port_bond_a
Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index c31bb80..6932a42 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2007-2013 Nicira, Inc.
+ * 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
@@ -35,12 +35,78 @@
#include <net/sctp/checksum.h>
#include "datapath.h"
+#include "flow.h"
#include "vport.h"
static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key,
const struct nlattr *attr, int len);
+struct deferred_action {
+ struct sk_buff *skb;
+ const struct nlattr *actions;
+
+ /* Store pkt_key clone when creating deferred action. */
+ struct sw_flow_key pkt_key;
+};
+
+#define DEFERRED_ACTION_FIFO_SIZE 10
+struct action_fifo {
+ int head;
+ int tail;
+ /* Deferred action fifo queue storage. */
+ struct deferred_action fifo[DEFERRED_ACTION_FIFO_SIZE];
+};
+
+static struct action_fifo __percpu *action_fifos;
+static DEFINE_PER_CPU(int, exec_actions_level);
+
+static void action_fifo_init(struct action_fifo *fifo)
+{
+ fifo->head = 0;
+ fifo->tail = 0;
+}
+
+static bool action_fifo_is_empty(struct action_fifo *fifo)
+{
+ return (fifo->head == fifo->tail);
+}
+
+static struct deferred_action *action_fifo_get(struct action_fifo *fifo)
+{
+ if (action_fifo_is_empty(fifo))
+ return NULL;
+
+ return &fifo->fifo[fifo->tail++];
+}
+
+static struct deferred_action *action_fifo_put(struct action_fifo *fifo)
+{
+ if (fifo->head >= DEFERRED_ACTION_FIFO_SIZE - 1)
+ return NULL;
+
+ return &fifo->fifo[fifo->head++];
+}
+
+/* Return true if fifo is not full */
+static struct deferred_action *add_deferred_actions(struct sk_buff *skb,
+ struct sw_flow_key *key,
+ const struct nlattr *attr)
+{
+ struct action_fifo *fifo;
+ struct deferred_action *da;
+
+ fifo = this_cpu_ptr(action_fifos);
+ da = action_fifo_put(fifo);
+ if (da) {
+ da->skb = skb;
+ da->actions = attr;
+ da->pkt_key = *key;
+ }
+
+ return da;
+}
+
static int make_writable(struct sk_buff *skb, int write_len)
{
if (!pskb_may_pull(skb, write_len))
@@ -485,8 +551,29 @@
/* Skip the sample action when out of memory. */
return 0;
- /* do_execute_actions() will consume the cloned skb. */
- return do_execute_actions(dp, skb, key, a, rem);
+ if (!add_deferred_actions(skb, key, a)) {
+ if (net_ratelimit())
+ pr_warn("%s: deferred actions limit reached, dropping sample action\n",
+ ovs_dp_name(dp));
+
+ kfree_skb(skb);
+ }
+ return 0;
+}
+
+static void execute_hash(struct sk_buff *skb, struct sw_flow_key *key,
+ const struct nlattr *attr)
+{
+ struct ovs_action_hash *hash_act = nla_data(attr);
+ u32 hash = 0;
+
+ /* OVS_HASH_ALG_L4 is the only possible hash algorithm. */
+ hash = skb_get_hash(skb);
+ hash = jhash_1word(hash, hash_act->hash_basis);
+ if (!hash)
+ hash = 0x1;
+
+ key->ovs_flow_hash = hash;
}
static int execute_set_action(struct sk_buff *skb,
@@ -535,6 +622,44 @@
return err;
}
+static int execute_recirc(struct datapath *dp, struct sk_buff *skb,
+ struct sw_flow_key *key,
+ const struct nlattr *a, int rem)
+{
+ struct deferred_action *da;
+ int err;
+
+ err = ovs_flow_key_update(skb, key);
+ if (err)
+ return err;
+
+ if (!last_action(a, rem)) {
+ /* Recirc action is the not the last action
+ * of the action list, need to clone the skb.
+ */
+ skb = skb_clone(skb, GFP_ATOMIC);
+
+ /* Skip the recirc action when out of memory, but
+ * continue on with the rest of the action list.
+ */
+ if (!skb)
+ return 0;
+ }
+
+ da = add_deferred_actions(skb, key, NULL);
+ if (da) {
+ da->pkt_key.recirc_id = nla_get_u32(a);
+ } else {
+ kfree_skb(skb);
+
+ if (net_ratelimit())
+ pr_warn("%s: deferred action limit reached, drop recirc action\n",
+ ovs_dp_name(dp));
+ }
+
+ return 0;
+}
+
/* Execute a list of actions against 'skb'. */
static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key,
@@ -566,6 +691,10 @@
output_userspace(dp, skb, key, a);
break;
+ case OVS_ACTION_ATTR_HASH:
+ execute_hash(skb, key, a);
+ break;
+
case OVS_ACTION_ATTR_PUSH_VLAN:
err = push_vlan(skb, nla_data(a));
if (unlikely(err)) /* skb already freed. */
@@ -576,6 +705,17 @@
err = pop_vlan(skb);
break;
+ case OVS_ACTION_ATTR_RECIRC:
+ err = execute_recirc(dp, skb, key, a, rem);
+ if (last_action(a, rem)) {
+ /* If this is the last action, the skb has
+ * been consumed or freed.
+ * Return immediately.
+ */
+ return err;
+ }
+ break;
+
case OVS_ACTION_ATTR_SET:
err = execute_set_action(skb, nla_data(a));
break;
@@ -601,12 +741,63 @@
return 0;
}
+static void process_deferred_actions(struct datapath *dp)
+{
+ struct action_fifo *fifo = this_cpu_ptr(action_fifos);
+
+ /* Do not touch the FIFO in case there is no deferred actions. */
+ if (action_fifo_is_empty(fifo))
+ return;
+
+ /* Finishing executing all deferred actions. */
+ do {
+ struct deferred_action *da = action_fifo_get(fifo);
+ struct sk_buff *skb = da->skb;
+ struct sw_flow_key *key = &da->pkt_key;
+ const struct nlattr *actions = da->actions;
+
+ if (actions)
+ do_execute_actions(dp, skb, key, actions,
+ nla_len(actions));
+ else
+ ovs_dp_process_packet(skb, key);
+ } while (!action_fifo_is_empty(fifo));
+
+ /* Reset FIFO for the next packet. */
+ action_fifo_init(fifo);
+}
+
/* Execute a list of actions against 'skb'. */
int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key)
{
- struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
+ int level = this_cpu_read(exec_actions_level);
+ struct sw_flow_actions *acts;
+ int err;
- return do_execute_actions(dp, skb, key,
- acts->actions, acts->actions_len);
+ acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
+
+ this_cpu_inc(exec_actions_level);
+ err = do_execute_actions(dp, skb, key,
+ acts->actions, acts->actions_len);
+
+ if (!level)
+ process_deferred_actions(dp);
+
+ this_cpu_dec(exec_actions_level);
+ return err;
+}
+
+int action_fifos_init(void)
+{
+ action_fifos = alloc_percpu(struct action_fifo);
+ if (!action_fifos)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void action_fifos_exit(void)
+{
+ free_percpu(action_fifos);
}