net: Get skb hash over flow_keys structure

This patch changes flow hashing to use jhash2 over the flow_keys
structure instead just doing jhash_3words over src, dst, and ports.
This method will allow us take more input into the hashing function
so that we can include full IPv6 addresses, VLAN, flow labels etc.
without needing to resort to xor'ing which makes for a poor hash.

Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 23 insertions, 4 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6b41c15efa27..cc612fc0a894 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1943,7 +1943,7 @@ static inline void skb_probe_transport_header(struct sk_buff *skb,
 	if (skb_transport_header_was_set(skb))
 		return;
 	else if (skb_flow_dissect_flow_keys(skb, &keys))
-		skb_set_transport_header(skb, keys.basic.thoff);
+		skb_set_transport_header(skb, keys.control.thoff);
 	else
 		skb_set_transport_header(skb, offset_hint);
 }
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index bac9c1421f58..cba6a10b214a 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -7,15 +7,24 @@
 #include <uapi/linux/if_ether.h>
 
 /**
+ * struct flow_dissector_key_control:
+ * @thoff: Transport header offset
+ */
+struct flow_dissector_key_control {
+	u16	thoff;
+	u16	padding;
+};
+
+/**
  * struct flow_dissector_key_basic:
  * @thoff: Transport header offset
  * @n_proto: Network header protocol (eg. IPv4/IPv6)
  * @ip_proto: Transport header protocol (eg. TCP/UDP)
  */
 struct flow_dissector_key_basic {
-	u16	thoff;
 	__be16	n_proto;
 	u8	ip_proto;
+	u8	padding;
 };
 
 /**
@@ -70,6 +79,7 @@ struct flow_dissector_key_eth_addrs {
 };
 
 enum flow_dissector_key_id {
+	FLOW_DISSECTOR_KEY_CONTROL, /* struct flow_dissector_key_control */
 	FLOW_DISSECTOR_KEY_BASIC, /* struct flow_dissector_key_basic */
 	FLOW_DISSECTOR_KEY_IPV4_ADDRS, /* struct flow_dissector_key_addrs */
 	FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS, /* struct flow_dissector_key_addrs */
@@ -109,11 +119,16 @@ static inline bool skb_flow_dissect(const struct sk_buff *skb,
 }
 
 struct flow_keys {
-	struct flow_dissector_key_addrs addrs;
-	struct flow_dissector_key_ports ports;
+	struct flow_dissector_key_control control;
+#define FLOW_KEYS_HASH_START_FIELD basic
 	struct flow_dissector_key_basic basic;
+	struct flow_dissector_key_ports ports;
+	struct flow_dissector_key_addrs addrs;
 };
 
+#define FLOW_KEYS_HASH_OFFSET		\
+	offsetof(struct flow_keys, FLOW_KEYS_HASH_START_FIELD)
+
 extern struct flow_dissector flow_keys_dissector;
 extern struct flow_dissector flow_keys_buf_dissector;
 
diff --git a/include/net/ip.h b/include/net/ip.h
index 9b976cf99122..16cfc87fed6c 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -360,6 +360,8 @@ static inline void inet_set_txhash(struct sock *sk)
 	struct inet_sock *inet = inet_sk(sk);
 	struct flow_keys keys;
 
+	memset(&keys, 0, sizeof(keys));
+
 	keys.addrs.src = inet->inet_saddr;
 	keys.addrs.dst = inet->inet_daddr;
 	keys.ports.src = inet->inet_sport;
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 35d485c78080..474ca466a091 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -699,6 +699,8 @@ static inline void ip6_set_txhash(struct sock *sk)
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct flow_keys keys;
 
+	memset(&keys, 0, sizeof(keys));
+
 	keys.addrs.src = (__force __be32)ipv6_addr_hash(&np->saddr);
 	keys.addrs.dst = (__force __be32)ipv6_addr_hash(&sk->sk_v6_daddr);
 	keys.ports.src = inet->inet_sport;