Merge branch 'flow_key_hashing'

Tom Herbert says:

====================
net: Increase inputs to flow_keys hashing

This patch set adds new fields to the flow_keys structure and hashes
over these fields to get a better flow hash. In particular, these
patches now include hashing over the full IPv6 addresses in order
to defend against address spoofing that always results in the
same hash. The new input also includes the Ethertype, L4 protocol,
VLAN, flow label, GRE keyid, and MPLS entropy label.

In order to increase hash inputs, we switch to using jhash2
which operates an an array of u32's. jhash2 operates on multiples of
three words. The data in the hash is constructed for that, and there
are are two variants for IPv4 and Ipv6 addressing. For IPv4 addresses,
jhash is performed over six u32's and for IPv6 it is done over twelve.

flow_keys can store either IPv4 or IPv6 addresses (addr_proto field
is a selector). ipv6_addr_hash is no longer used to convert addresses
for setting in flow table. For legacy uses of flow keys outside of
flow_dissector the flow_get_u32_src and flow_get_u32_dst functions
have been added to get u32 representation representations of addresses
in flow_keys.

For flow lables we also eliminate the short circuit in flow_dissector
for non-zero flow label. The flow label is now considered additional
input to ports.

Testing: Ran netperf TCP_RR for 200 flows using IPv4 and IPv6 comparing
before the patches and with the patches. Did not detect any performance
degradation.

v2:
  - Took out MPLS entropy label. Will add this later.
v3:
  - Ensure hash start offset is a four byte boundary. Add BUG_BUILD_ON
    to check for this.
  - Fixes sparse error in GRE to get entropy from keyid.
v4:
  - Rebase to Jiri changes to generalize flow dissection
  - Support TIPC as its own address
  - Bring back MPLS entropy label dissection
  - Remove FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS

v5:
  - Minor fixes from feedback

v6:
  - Cleanup and sparse issue with flow label
  - Change keyid to returned by flow_dissector to be __be32
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 118 insertions, 27 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..1a8c22419936 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -7,31 +7,79 @@
 #include <uapi/linux/if_ether.h>
 
 /**
+ * struct flow_dissector_key_control:
+ * @thoff: Transport header offset
+ */
+struct flow_dissector_key_control {
+	u16	thoff;
+	u16	addr_type;
+};
+
+/**
  * 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;
+};
+
+struct flow_dissector_key_tags {
+	u32	vlan_id:12,
+		flow_label:20;
+};
+
+struct flow_dissector_key_keyid {
+	__be32	keyid;
 };
 
 /**
- * struct flow_dissector_key_addrs:
- * @src: source ip address in case of IPv4
- *	 For IPv6 it contains 32bit hash of src address
- * @dst: destination ip address in case of IPv4
- *	 For IPv6 it contains 32bit hash of dst address
+ * struct flow_dissector_key_ipv4_addrs:
+ * @src: source ip address
+ * @dst: destination ip address
  */
-struct flow_dissector_key_addrs {
+struct flow_dissector_key_ipv4_addrs {
 	/* (src,dst) must be grouped, in the same way than in IP header */
 	__be32 src;
 	__be32 dst;
 };
 
 /**
+ * struct flow_dissector_key_ipv6_addrs:
+ * @src: source ip address
+ * @dst: destination ip address
+ */
+struct flow_dissector_key_ipv6_addrs {
+	/* (src,dst) must be grouped, in the same way than in IP header */
+	struct in6_addr src;
+	struct in6_addr dst;
+};
+
+/**
+ * struct flow_dissector_key_tipc_addrs:
+ * @srcnode: source node address
+ */
+struct flow_dissector_key_tipc_addrs {
+	__be32 srcnode;
+};
+
+/**
+ * struct flow_dissector_key_addrs:
+ * @v4addrs: IPv4 addresses
+ * @v6addrs: IPv6 addresses
+ */
+struct flow_dissector_key_addrs {
+	union {
+		struct flow_dissector_key_ipv4_addrs v4addrs;
+		struct flow_dissector_key_ipv6_addrs v6addrs;
+		struct flow_dissector_key_tipc_addrs tipcaddrs;
+	};
+};
+
+/**
  * flow_dissector_key_tp_ports:
  *	@ports: port numbers of Transport header
  *		src: source port number
@@ -47,16 +95,6 @@ struct flow_dissector_key_ports {
 	};
 };
 
-/**
- * struct flow_dissector_key_ipv6_addrs:
- * @src: source ip address
- * @dst: destination ip address
- */
-struct flow_dissector_key_ipv6_addrs {
-	/* (src,dst) must be grouped, in the same way than in IP header */
-	struct in6_addr src;
-	struct in6_addr dst;
-};
 
 /**
  * struct flow_dissector_key_eth_addrs:
@@ -70,12 +108,17 @@ 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 */
-	FLOW_DISSECTOR_KEY_PORTS, /* struct flow_dissector_key_ports */
+	FLOW_DISSECTOR_KEY_IPV4_ADDRS, /* struct flow_dissector_key_ipv4_addrs */
 	FLOW_DISSECTOR_KEY_IPV6_ADDRS, /* struct flow_dissector_key_ipv6_addrs */
+	FLOW_DISSECTOR_KEY_PORTS, /* struct flow_dissector_key_ports */
 	FLOW_DISSECTOR_KEY_ETH_ADDRS, /* struct flow_dissector_key_eth_addrs */
+	FLOW_DISSECTOR_KEY_TIPC_ADDRS, /* struct flow_dissector_key_tipc_addrs */
+	FLOW_DISSECTOR_KEY_VLANID, /* struct flow_dissector_key_flow_tags */
+	FLOW_DISSECTOR_KEY_FLOW_LABEL, /* struct flow_dissector_key_flow_tags */
+	FLOW_DISSECTOR_KEY_GRE_KEYID, /* struct flow_dissector_key_keyid */
+	FLOW_DISSECTOR_KEY_MPLS_ENTROPY, /* struct flow_dissector_key_keyid */
 
 	FLOW_DISSECTOR_KEY_MAX,
 };
@@ -109,11 +152,21 @@ 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_tags tags;
+	struct flow_dissector_key_keyid keyid;
+	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)
+
+__be32 flow_get_u32_src(const struct flow_keys *flow);
+__be32 flow_get_u32_dst(const struct flow_keys *flow);
+
 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..0750a186ea63 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -355,13 +355,30 @@ static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 				  skb->len, proto, 0);
 }
 
+/* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
+ * Equivalent to :	flow->v4addrs.src = iph->saddr;
+ *			flow->v4addrs.dst = iph->daddr;
+ */
+static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
+					    const struct iphdr *iph)
+{
+	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
+		     offsetof(typeof(flow->addrs), v4addrs.src) +
+			      sizeof(flow->addrs.v4addrs.src));
+	memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
+	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+}
+
 static inline void inet_set_txhash(struct sock *sk)
 {
 	struct inet_sock *inet = inet_sk(sk);
 	struct flow_keys keys;
 
-	keys.addrs.src = inet->inet_saddr;
-	keys.addrs.dst = inet->inet_daddr;
+	memset(&keys, 0, sizeof(keys));
+
+	keys.addrs.v4addrs.src = inet->inet_saddr;
+	keys.addrs.v4addrs.dst = inet->inet_daddr;
+	keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 	keys.ports.src = inet->inet_sport;
 	keys.ports.dst = inet->inet_dport;
 
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 35d485c78080..82dbdb092a5d 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -692,6 +692,20 @@ static inline int ip6_sk_dst_hoplimit(struct ipv6_pinfo *np, struct flowi6 *fl6,
 	return hlimit;
 }
 
+/* copy IPv6 saddr & daddr to flow_keys, possibly using 64bit load/store
+ * Equivalent to :	flow->v6addrs.src = iph->saddr;
+ *			flow->v6addrs.dst = iph->daddr;
+ */
+static inline void iph_to_flow_copy_v6addrs(struct flow_keys *flow,
+					    const struct ipv6hdr *iph)
+{
+	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v6addrs.dst) !=
+		     offsetof(typeof(flow->addrs), v6addrs.src) +
+		     sizeof(flow->addrs.v6addrs.src));
+	memcpy(&flow->addrs.v6addrs, &iph->saddr, sizeof(flow->addrs.v6addrs));
+	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+}
+
 #if IS_ENABLED(CONFIG_IPV6)
 static inline void ip6_set_txhash(struct sock *sk)
 {
@@ -699,8 +713,13 @@ static inline void ip6_set_txhash(struct sock *sk)
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct flow_keys keys;
 
-	keys.addrs.src = (__force __be32)ipv6_addr_hash(&np->saddr);
-	keys.addrs.dst = (__force __be32)ipv6_addr_hash(&sk->sk_v6_daddr);
+	memset(&keys, 0, sizeof(keys));
+
+	memcpy(&keys.addrs.v6addrs.src, &np->saddr,
+	       sizeof(keys.addrs.v6addrs.src));
+	memcpy(&keys.addrs.v6addrs.dst, &sk->sk_v6_daddr,
+	       sizeof(keys.addrs.v6addrs.dst));
+	keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 	keys.ports.src = inet->inet_sport;
 	keys.ports.dst = inet->inet_dport;
 
diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h
index 589ced069e8a..641338bef651 100644
--- a/include/uapi/linux/in.h
+++ b/include/uapi/linux/in.h
@@ -69,6 +69,8 @@ enum {
 #define IPPROTO_SCTP		IPPROTO_SCTP
   IPPROTO_UDPLITE = 136,	/* UDP-Lite (RFC 3828)			*/
 #define IPPROTO_UDPLITE		IPPROTO_UDPLITE
+  IPPROTO_MPLS = 137,		/* MPLS in IP (RFC 4023)		*/
+#define IPPROTO_MPLS		IPPROTO_MPLS
   IPPROTO_RAW = 255,		/* Raw IP packets			*/
 #define IPPROTO_RAW		IPPROTO_RAW
   IPPROTO_MAX