[ovs-dev] [recirc datapath V3 RFC 1/2] datapath: add hash action

Andy Zhou azhou at nicira.com
Thu Apr 17 06:49:04 UTC 2014


Signed-off-by: Andy Zhou <azhou at nicira.com>

----
V2->V3:
       * rename dp_hash to ovs_flow_hash
       * Simplify netlink message error checking logic
       * other cleanups
---
 datapath/actions.c      | 19 ++++++++++++++++++-
 datapath/flow.h         |  1 +
 datapath/flow_netlink.c | 37 +++++++++++++++++++++++++++++++++++--
 3 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/datapath/actions.c b/datapath/actions.c
index 82cfd2d..820075f 100644
--- a/datapath/actions.c
+++ b/datapath/actions.c
@@ -460,6 +460,19 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
 				  nla_len(acts_list), true);
 }
 
+static void execute_hash(struct sk_buff *skb, const struct nlattr *attr)
+{
+	struct sw_flow_key *key = OVS_CB(skb)->pkt_key;
+	u32 hash = 0;
+
+	/* OVS_HASH_ALG_L4 is the only possible hash algorithm.  */
+	hash = skb_get_rxhash(skb);
+	if (!hash)
+		hash = 0x1;
+
+	key->ovs_flow_hash = hash;
+}
+
 static int execute_set_action(struct sk_buff *skb,
 				 const struct nlattr *nested_attr)
 {
@@ -511,7 +524,7 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 			const struct nlattr *attr, int len, bool keep_skb)
 {
 	/* Every output action needs a separate clone of 'skb', but the common
-	 * case is just a single output action, so that doing a clone and
+	 * case is just a single output action, so that doin a clone and
 	 * then freeing the original skbuff is wasteful.  So the following code
 	 * is slightly obscure just to avoid that. */
 	int prev_port = -1;
@@ -536,6 +549,10 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 			output_userspace(dp, skb, a);
 			break;
 
+		case OVS_ACTION_ATTR_HASH:
+			execute_hash(skb, a);
+			break;
+
 		case OVS_ACTION_ATTR_PUSH_VLAN:
 			err = push_vlan(skb, nla_data(a));
 			if (unlikely(err)) /* skb already freed. */
diff --git a/datapath/flow.h b/datapath/flow.h
index 1bb6ce0..a4cb57e 100644
--- a/datapath/flow.h
+++ b/datapath/flow.h
@@ -74,6 +74,7 @@ struct sw_flow_key {
 		u32	skb_mark;	/* SKB mark. */
 		u16	in_port;	/* Input switch port (or DP_MAX_PORTS). */
 	} __packed phy; /* Safe when right after 'tun_key'. */
+	u32 ovs_flow_hash;		/* Datapath computed hash value.  */
 	struct {
 		u8     src[ETH_ALEN];	/* Ethernet source address. */
 		u8     dst[ETH_ALEN];	/* Ethernet destination address. */
diff --git a/datapath/flow_netlink.c b/datapath/flow_netlink.c
index 5c32cd0..f464a5b 100644
--- a/datapath/flow_netlink.c
+++ b/datapath/flow_netlink.c
@@ -123,6 +123,7 @@ static bool match_validate(const struct sw_flow_match *match,
 			| (1ULL << OVS_KEY_ATTR_ICMP)
 			| (1ULL << OVS_KEY_ATTR_ICMPV6)
 			| (1ULL << OVS_KEY_ATTR_ARP)
+			| (1ULL << OVS_KEY_ATTR_DP_HASH)
 			| (1ULL << OVS_KEY_ATTR_ND));
 
 	/* Always allowed mask fields. */
@@ -130,7 +131,6 @@ static bool match_validate(const struct sw_flow_match *match,
 		       | (1ULL << OVS_KEY_ATTR_IN_PORT)
 		       | (1ULL << OVS_KEY_ATTR_ETHERTYPE));
 
-	/* Check key attributes. */
 	if (match->key->eth.type == htons(ETH_P_ARP)
 			|| match->key->eth.type == htons(ETH_P_RARP)) {
 		key_expected |= 1ULL << OVS_KEY_ATTR_ARP;
@@ -252,6 +252,7 @@ static const int ovs_key_lens[OVS_KEY_ATTR_MAX + 1] = {
 	[OVS_KEY_ATTR_ICMPV6] = sizeof(struct ovs_key_icmpv6),
 	[OVS_KEY_ATTR_ARP] = sizeof(struct ovs_key_arp),
 	[OVS_KEY_ATTR_ND] = sizeof(struct ovs_key_nd),
+	[OVS_KEY_ATTR_DP_HASH] = sizeof(u32),
 	[OVS_KEY_ATTR_TUNNEL] = -1,
 };
 
@@ -455,6 +456,19 @@ static int ipv4_tun_to_nlattr(struct sk_buff *skb,
 static int metadata_from_nlattrs(struct sw_flow_match *match,  u64 *attrs,
 				 const struct nlattr **a, bool is_mask)
 {
+
+	if (*attrs & (1ULL << OVS_KEY_ATTR_DP_HASH)) {
+		u32 hash_val = nla_get_u32(a[OVS_KEY_ATTR_DP_HASH]);
+
+		if (!is_mask && !hash_val) {
+			OVS_NLERR("Hash value can not be zero\n");
+			return -EINVAL;
+		}
+
+		SW_FLOW_KEY_PUT(match, ovs_flow_hash, hash_val, is_mask);
+		*attrs &= ~(1ULL << OVS_KEY_ATTR_DP_HASH);
+	}
+
 	if (*attrs & (1ULL << OVS_KEY_ATTR_PRIORITY)) {
 		SW_FLOW_KEY_PUT(match, phy.priority,
 			  nla_get_u32(a[OVS_KEY_ATTR_PRIORITY]), is_mask);
@@ -859,6 +873,7 @@ int ovs_nla_get_flow_metadata(struct sw_flow *flow,
 	flow->key.phy.in_port = DP_MAX_PORTS;
 	flow->key.phy.priority = 0;
 	flow->key.phy.skb_mark = 0;
+	flow->key.ovs_flow_hash = 0;
 	memset(tun_key, 0, sizeof(flow->key.tun_key));
 
 	err = parse_flow_nlattrs(attr, a, &attrs);
@@ -882,6 +897,11 @@ int ovs_nla_put_flow(const struct sw_flow_key *swkey,
 	struct nlattr *nla, *encap;
 	bool is_mask = (swkey != output);
 
+	if ((swkey->ovs_flow_hash) &&
+			(nla_put_u32(skb, OVS_KEY_ATTR_DP_HASH,
+				     output->ovs_flow_hash)))
+		goto nla_put_failure;
+
 	if (nla_put_u32(skb, OVS_KEY_ATTR_PRIORITY, output->phy.priority))
 		goto nla_put_failure;
 
@@ -1422,7 +1442,8 @@ int ovs_nla_copy_actions(const struct nlattr *attr,
 			[OVS_ACTION_ATTR_PUSH_VLAN] = sizeof(struct ovs_action_push_vlan),
 			[OVS_ACTION_ATTR_POP_VLAN] = 0,
 			[OVS_ACTION_ATTR_SET] = (u32)-1,
-			[OVS_ACTION_ATTR_SAMPLE] = (u32)-1
+			[OVS_ACTION_ATTR_SAMPLE] = (u32)-1,
+			[OVS_ACTION_ATTR_HASH] = sizeof(struct ovs_action_hash)
 		};
 		const struct ovs_action_push_vlan *vlan;
 		int type = nla_type(a);
@@ -1449,6 +1470,18 @@ int ovs_nla_copy_actions(const struct nlattr *attr,
 				return -EINVAL;
 			break;
 
+		case OVS_ACTION_ATTR_HASH: {
+			const struct ovs_action_hash *act_hash = nla_data(a);
+
+			switch (act_hash->hash_alg) {
+			case OVS_HASH_ALG_L4:
+				break;
+			default:
+				return  -EINVAL;
+			}
+
+			break;
+		}
 
 		case OVS_ACTION_ATTR_POP_VLAN:
 			break;
-- 
1.9.1




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