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Tom Herbert says:

====================
flow_dissector: Paramterize dissection and other features

This patch set adds some new capabilities to flow_dissector:

- Add flags to flow dissector functions to control dissection
  - Flag to stop dissection when L3 header is seen (don't
    dissect L4)
  - Flag to stop dissection when encapsulation is detected
  - Flag to parse first fragment of fragmented packet. This
    may provide L4 ports
- Added new reporting in key_control
  - Packet is a fragment
  - Packet is a first fragment
  - Packet has encapsulation

Also:
  - Make __skb_set_sw_hash a general function
  - Create functions to get a flow hash based on flowi4 or flowi6
    structures without an reference to an skbuff
  - Ignore flow dissector return value from ___skb_get_hash. Just
    use whatever key fields are found to make a hash

Tested:

Ran 200 netperf TCP_RR instances for IPv6 and IPv4. Did not see any
regression. Ran UDP_RR with 10000 byte request and response size
for IPv4 and IPv6, no regression observed however I did see better
performance with IPv6 flow labels due to use of flow labels for L4
hash.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
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@davem330
davem330 committed Sep 1, 2015
2 parents d3d11fe + 6db61d7 commit 41ecc3d
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Showing 12 changed files with 267 additions and 128 deletions.
2 changes: 1 addition & 1 deletion drivers/net/bonding/bond_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3095,7 +3095,7 @@ static bool bond_flow_dissect(struct bonding *bond, struct sk_buff *skb,
int noff, proto = -1;

if (bond->params.xmit_policy > BOND_XMIT_POLICY_LAYER23)
return skb_flow_dissect_flow_keys(skb, fk);
return skb_flow_dissect_flow_keys(skb, fk, 0);

fk->ports.ports = 0;
noff = skb_network_offset(skb);
Expand Down
2 changes: 1 addition & 1 deletion drivers/net/ethernet/cisco/enic/enic_clsf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -177,7 +177,7 @@ int enic_rx_flow_steer(struct net_device *dev, const struct sk_buff *skb,
int res, i;

enic = netdev_priv(dev);
res = skb_flow_dissect_flow_keys(skb, &keys);
res = skb_flow_dissect_flow_keys(skb, &keys, 0);
if (!res || keys.basic.n_proto != htons(ETH_P_IP) ||
(keys.basic.ip_proto != IPPROTO_TCP &&
keys.basic.ip_proto != IPPROTO_UDP))
Expand Down
2 changes: 1 addition & 1 deletion drivers/net/hyperv/netvsc_drv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -239,7 +239,7 @@ static bool netvsc_set_hash(u32 *hash, struct sk_buff *skb)
struct flow_keys flow;
int data_len;

if (!skb_flow_dissect_flow_keys(skb, &flow) ||
if (!skb_flow_dissect_flow_keys(skb, &flow, 0) ||
!(flow.basic.n_proto == htons(ETH_P_IP) ||
flow.basic.n_proto == htons(ETH_P_IPV6)))
return false;
Expand Down
113 changes: 92 additions & 21 deletions include/linux/skbuff.h
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Original file line number Diff line number Diff line change
Expand Up @@ -937,14 +937,90 @@ enum pkt_hash_types {
PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */
};

static inline void
skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
static inline void skb_clear_hash(struct sk_buff *skb)
{
skb->l4_hash = (type == PKT_HASH_TYPE_L4);
skb->hash = 0;
skb->sw_hash = 0;
skb->l4_hash = 0;
}

static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
{
if (!skb->l4_hash)
skb_clear_hash(skb);
}

static inline void
__skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
{
skb->l4_hash = is_l4;
skb->sw_hash = is_sw;
skb->hash = hash;
}

static inline void
skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
{
/* Used by drivers to set hash from HW */
__skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
}

static inline void
__skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
{
__skb_set_hash(skb, hash, true, is_l4);
}

void __skb_get_hash(struct sk_buff *skb);
u32 skb_get_poff(const struct sk_buff *skb);
u32 __skb_get_poff(const struct sk_buff *skb, void *data,
const struct flow_keys *keys, int hlen);
__be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
void *data, int hlen_proto);

static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
int thoff, u8 ip_proto)
{
return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
}

void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
const struct flow_dissector_key *key,
unsigned int key_count);

bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container,
void *data, __be16 proto, int nhoff, int hlen,
unsigned int flags);

static inline bool skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container, unsigned int flags)
{
return __skb_flow_dissect(skb, flow_dissector, target_container,
NULL, 0, 0, 0, flags);
}

static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
struct flow_keys *flow,
unsigned int flags)
{
memset(flow, 0, sizeof(*flow));
return __skb_flow_dissect(skb, &flow_keys_dissector, flow,
NULL, 0, 0, 0, flags);
}

static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys *flow,
void *data, __be16 proto,
int nhoff, int hlen,
unsigned int flags)
{
memset(flow, 0, sizeof(*flow));
return __skb_flow_dissect(NULL, &flow_keys_buf_dissector, flow,
data, proto, nhoff, hlen, flags);
}

static inline __u32 skb_get_hash(struct sk_buff *skb)
{
if (!skb->l4_hash && !skb->sw_hash)
Expand All @@ -957,8 +1033,12 @@ __u32 __skb_get_hash_flowi6(struct sk_buff *skb, struct flowi6 *fl6);

static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, struct flowi6 *fl6)
{
if (!skb->l4_hash && !skb->sw_hash)
__skb_get_hash_flowi6(skb, fl6);
if (!skb->l4_hash && !skb->sw_hash) {
struct flow_keys keys;

__skb_set_sw_hash(skb, __get_hash_from_flowi6(fl6, &keys),
flow_keys_have_l4(&keys));
}

return skb->hash;
}
Expand All @@ -967,8 +1047,12 @@ __u32 __skb_get_hash_flowi4(struct sk_buff *skb, struct flowi4 *fl);

static inline __u32 skb_get_hash_flowi4(struct sk_buff *skb, struct flowi4 *fl4)
{
if (!skb->l4_hash && !skb->sw_hash)
__skb_get_hash_flowi4(skb, fl4);
if (!skb->l4_hash && !skb->sw_hash) {
struct flow_keys keys;

__skb_set_sw_hash(skb, __get_hash_from_flowi4(fl4, &keys),
flow_keys_have_l4(&keys));
}

return skb->hash;
}
Expand All @@ -980,19 +1064,6 @@ static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
return skb->hash;
}

static inline void skb_clear_hash(struct sk_buff *skb)
{
skb->hash = 0;
skb->sw_hash = 0;
skb->l4_hash = 0;
}

static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
{
if (!skb->l4_hash)
skb_clear_hash(skb);
}

static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
{
to->hash = from->hash;
Expand Down Expand Up @@ -1978,7 +2049,7 @@ 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))
else if (skb_flow_dissect_flow_keys(skb, &keys, 0))
skb_set_transport_header(skb, keys.control.thoff);
else
skb_set_transport_header(skb, offset_hint);
Expand Down
19 changes: 19 additions & 0 deletions include/net/flow.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
#include <linux/socket.h>
#include <linux/in6.h>
#include <linux/atomic.h>
#include <net/flow_dissector.h>

/*
* ifindex generation is per-net namespace, and loopback is
Expand Down Expand Up @@ -243,4 +244,22 @@ void flow_cache_flush(struct net *net);
void flow_cache_flush_deferred(struct net *net);
extern atomic_t flow_cache_genid;

__u32 __get_hash_from_flowi6(struct flowi6 *fl6, struct flow_keys *keys);

static inline __u32 get_hash_from_flowi6(struct flowi6 *fl6)
{
struct flow_keys keys;

return __get_hash_from_flowi6(fl6, &keys);
}

__u32 __get_hash_from_flowi4(struct flowi4 *fl4, struct flow_keys *keys);

static inline __u32 get_hash_from_flowi4(struct flowi4 *fl4)
{
struct flow_keys keys;

return __get_hash_from_flowi4(fl4, &keys);
}

#endif
65 changes: 15 additions & 50 deletions include/net/flow_dissector.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,6 @@
#define _NET_FLOW_DISSECTOR_H

#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/in6.h>
#include <uapi/linux/if_ether.h>

Expand All @@ -13,6 +12,9 @@
struct flow_dissector_key_control {
u16 thoff;
u16 addr_type;
u32 is_fragment:1;
u32 first_frag:1;
u32 encapsulation:1;
};

/**
Expand Down Expand Up @@ -123,6 +125,11 @@ enum flow_dissector_key_id {
FLOW_DISSECTOR_KEY_MAX,
};

#define FLOW_DISSECTOR_F_PARSE_1ST_FRAG BIT(0)
#define FLOW_DISSECTOR_F_STOP_AT_L3 BIT(1)
#define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL BIT(2)
#define FLOW_DISSECTOR_F_STOP_AT_ENCAP BIT(3)

struct flow_dissector_key {
enum flow_dissector_key_id key_id;
size_t offset; /* offset of struct flow_dissector_key_*
Expand All @@ -134,23 +141,6 @@ struct flow_dissector {
unsigned short int offset[FLOW_DISSECTOR_KEY_MAX];
};

void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
const struct flow_dissector_key *key,
unsigned int key_count);

bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container,
void *data, __be16 proto, int nhoff, int hlen);

static inline bool skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container)
{
return __skb_flow_dissect(skb, flow_dissector, target_container,
NULL, 0, 0, 0);
}

struct flow_keys {
struct flow_dissector_key_control control;
#define FLOW_KEYS_HASH_START_FIELD basic
Expand All @@ -170,38 +160,6 @@ __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;

static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
struct flow_keys *flow)
{
memset(flow, 0, sizeof(*flow));
return __skb_flow_dissect(skb, &flow_keys_dissector, flow,
NULL, 0, 0, 0);
}

static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys *flow,
void *data, __be16 proto,
int nhoff, int hlen)
{
memset(flow, 0, sizeof(*flow));
return __skb_flow_dissect(NULL, &flow_keys_buf_dissector, flow,
data, proto, nhoff, hlen);
}

__be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
void *data, int hlen_proto);

static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
int thoff, u8 ip_proto)
{
return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
}

u32 flow_hash_from_keys(struct flow_keys *keys);
void __skb_get_hash(struct sk_buff *skb);
u32 skb_get_poff(const struct sk_buff *skb);
u32 __skb_get_poff(const struct sk_buff *skb, void *data,
const struct flow_keys *keys, int hlen);

/* struct flow_keys_digest:
*
* This structure is used to hold a digest of the full flow keys. This is a
Expand All @@ -217,4 +175,11 @@ struct flow_keys_digest {
void make_flow_keys_digest(struct flow_keys_digest *digest,
const struct flow_keys *flow);

static inline bool flow_keys_have_l4(struct flow_keys *keys)
{
return (keys->ports.ports || keys->tags.flow_label);
}

u32 flow_hash_from_keys(struct flow_keys *keys);

#endif
36 changes: 36 additions & 0 deletions net/core/flow.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#include <linux/cpumask.h>
#include <linux/mutex.h>
#include <net/flow.h>
#include <net/flow_dissector.h>
#include <linux/atomic.h>
#include <linux/security.h>
#include <net/net_namespace.h>
Expand Down Expand Up @@ -509,3 +510,38 @@ void flow_cache_fini(struct net *net)
fc->percpu = NULL;
}
EXPORT_SYMBOL(flow_cache_fini);

__u32 __get_hash_from_flowi6(struct flowi6 *fl6, struct flow_keys *keys)
{
memset(keys, 0, sizeof(*keys));

memcpy(&keys->addrs.v6addrs.src, &fl6->saddr,
sizeof(keys->addrs.v6addrs.src));
memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr,
sizeof(keys->addrs.v6addrs.dst));
keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
keys->ports.src = fl6->fl6_sport;
keys->ports.dst = fl6->fl6_dport;
keys->keyid.keyid = fl6->fl6_gre_key;
keys->tags.flow_label = (__force u32)fl6->flowlabel;
keys->basic.ip_proto = fl6->flowi6_proto;

return flow_hash_from_keys(keys);
}
EXPORT_SYMBOL(__get_hash_from_flowi6);

__u32 __get_hash_from_flowi4(struct flowi4 *fl4, struct flow_keys *keys)
{
memset(keys, 0, sizeof(*keys));

keys->addrs.v4addrs.src = fl4->saddr;
keys->addrs.v4addrs.dst = fl4->daddr;
keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
keys->ports.src = fl4->fl4_sport;
keys->ports.dst = fl4->fl4_dport;
keys->keyid.keyid = fl4->fl4_gre_key;
keys->basic.ip_proto = fl4->flowi4_proto;

return flow_hash_from_keys(keys);
}
EXPORT_SYMBOL(__get_hash_from_flowi4);
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