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>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6b41c15..cc612fc 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1943,7 +1943,7 @@
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 bac9c14..cba6a10 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 @@
};
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 @@
}
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 9b976cf..16cfc87 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -360,6 +360,8 @@
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 35d485c..474ca46 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -699,6 +699,8 @@
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;
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 0763795..55b5f29 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -57,10 +57,12 @@
flow_dissector->offset[key->key_id] = key->offset;
}
- /* Ensure that the dissector always includes basic key. That way
- * we are able to avoid handling lack of it in fast path.
+ /* Ensure that the dissector always includes control and basic key.
+ * That way we are able to avoid handling lack of these in fast path.
*/
BUG_ON(!skb_flow_dissector_uses_key(flow_dissector,
+ FLOW_DISSECTOR_KEY_CONTROL));
+ BUG_ON(!skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_BASIC));
}
EXPORT_SYMBOL(skb_flow_dissector_init);
@@ -120,6 +122,7 @@
void *target_container,
void *data, __be16 proto, int nhoff, int hlen)
{
+ struct flow_dissector_key_control *key_control;
struct flow_dissector_key_basic *key_basic;
struct flow_dissector_key_addrs *key_addrs;
struct flow_dissector_key_ports *key_ports;
@@ -132,6 +135,13 @@
hlen = skb_headlen(skb);
}
+ /* It is ensured by skb_flow_dissector_init() that control key will
+ * be always present.
+ */
+ key_control = skb_flow_dissector_target(flow_dissector,
+ FLOW_DISSECTOR_KEY_CONTROL,
+ target_container);
+
/* It is ensured by skb_flow_dissector_init() that basic key will
* be always present.
*/
@@ -219,7 +229,7 @@
key_basic->n_proto = proto;
key_basic->ip_proto = ip_proto;
- key_basic->thoff = (u16)nhoff;
+ key_control->thoff = (u16)nhoff;
if (skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_PORTS)) {
@@ -275,7 +285,7 @@
if (!hdr)
return false;
key_basic->n_proto = proto;
- key_basic->thoff = (u16)nhoff;
+ key_control->thoff = (u16)nhoff;
if (skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_HASH_ADDRS)) {
@@ -288,7 +298,7 @@
return true;
}
case htons(ETH_P_FCOE):
- key_basic->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
+ key_control->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
/* fall through */
default:
return false;
@@ -345,7 +355,7 @@
key_basic->n_proto = proto;
key_basic->ip_proto = ip_proto;
- key_basic->thoff = (u16) nhoff;
+ key_control->thoff = (u16)nhoff;
if (skb_flow_dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_PORTS)) {
@@ -366,9 +376,21 @@
net_get_random_once(&hashrnd, sizeof(hashrnd));
}
-static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c, u32 keyval)
+static __always_inline u32 __flow_hash_words(u32 *words, u32 length, u32 keyval)
{
- return jhash_3words(a, b, c, keyval);
+ return jhash2(words, length, keyval);
+}
+
+static inline void *flow_keys_hash_start(struct flow_keys *flow)
+{
+ BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32));
+ return (void *)flow + FLOW_KEYS_HASH_OFFSET;
+}
+
+static inline size_t flow_keys_hash_length(struct flow_keys *flow)
+{
+ BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
+ return (sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) / sizeof(u32);
}
static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
@@ -383,10 +405,8 @@
swap(keys->ports.src, keys->ports.dst);
}
- hash = __flow_hash_3words((__force u32)keys->addrs.dst,
- (__force u32)keys->addrs.src,
- (__force u32)keys->ports.ports,
- keyval);
+ hash = __flow_hash_words((u32 *)flow_keys_hash_start(keys),
+ flow_keys_hash_length(keys), keyval);
if (!hash)
hash = 1;
@@ -473,7 +493,7 @@
u32 __skb_get_poff(const struct sk_buff *skb, void *data,
const struct flow_keys *keys, int hlen)
{
- u32 poff = keys->basic.thoff;
+ u32 poff = keys->control.thoff;
switch (keys->basic.ip_proto) {
case IPPROTO_TCP: {
@@ -537,6 +557,10 @@
static const struct flow_dissector_key flow_keys_dissector_keys[] = {
{
+ .key_id = FLOW_DISSECTOR_KEY_CONTROL,
+ .offset = offsetof(struct flow_keys, control),
+ },
+ {
.key_id = FLOW_DISSECTOR_KEY_BASIC,
.offset = offsetof(struct flow_keys, basic),
},
@@ -556,6 +580,10 @@
static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
{
+ .key_id = FLOW_DISSECTOR_KEY_CONTROL,
+ .offset = offsetof(struct flow_keys, control),
+ },
+ {
.key_id = FLOW_DISSECTOR_KEY_BASIC,
.offset = offsetof(struct flow_keys, basic),
},
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 8c8f34e..5a7d66c 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -25,6 +25,7 @@
struct fl_flow_key {
int indev_ifindex;
+ struct flow_dissector_key_control control;
struct flow_dissector_key_basic basic;
struct flow_dissector_key_eth_addrs eth;
union {
@@ -347,6 +348,7 @@
struct flow_dissector_key keys[FLOW_DISSECTOR_KEY_MAX];
size_t cnt = 0;
+ FL_KEY_SET(keys, cnt, FLOW_DISSECTOR_KEY_CONTROL, control);
FL_KEY_SET(keys, cnt, FLOW_DISSECTOR_KEY_BASIC, basic);
FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,
FLOW_DISSECTOR_KEY_ETH_ADDRS, eth);