From 72a338bcc6ae51e01c95d687e5d775e3fe52eff1 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 4 May 2018 11:32:59 +0200 Subject: [PATCH] net: core: rework basic flow dissection helper When the core networking needs to detect the transport offset in a given packet and parse it explicitly, a full-blown flow_keys struct is used for storage. This patch introduces a smaller keys store, rework the basic flow dissect helper to use it, and apply this new helper where possible - namely in skb_probe_transport_header(). The used flow dissector data structures are renamed to match more closely the new role. The above gives ~50% performance improvement in micro benchmarking around skb_probe_transport_header() and ~30% around eth_get_headlen(), mostly due to the smaller memset. Small, but measurable improvement is measured also in macro benchmarking. v1 -> v2: use the new helper in eth_get_headlen() and skb_get_poff(), as per DaveM suggestion Suggested-by: David Miller Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- include/linux/skbuff.h | 18 ++++++++++-------- include/net/flow_dissector.h | 7 ++++++- net/core/flow_dissector.c | 17 +++++++++-------- net/ethernet/eth.c | 6 +++--- 4 files changed, 28 insertions(+), 20 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 908d66e55b14..693564a9a979 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1171,7 +1171,7 @@ void __skb_get_hash(struct sk_buff *skb); u32 __skb_get_hash_symmetric(const 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); + const struct flow_keys_basic *keys, int hlen); __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, void *data, int hlen_proto); @@ -1208,13 +1208,14 @@ static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb, 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) +static inline bool +skb_flow_dissect_flow_keys_basic(const struct sk_buff *skb, + struct flow_keys_basic *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, + return __skb_flow_dissect(skb, &flow_keys_basic_dissector, flow, data, proto, nhoff, hlen, flags); } @@ -2350,11 +2351,12 @@ static inline void skb_pop_mac_header(struct sk_buff *skb) static inline void skb_probe_transport_header(struct sk_buff *skb, const int offset_hint) { - struct flow_keys keys; + struct flow_keys_basic keys; if (skb_transport_header_was_set(skb)) return; - else if (skb_flow_dissect_flow_keys(skb, &keys, 0)) + + if (skb_flow_dissect_flow_keys_basic(skb, &keys, 0, 0, 0, 0, 0)) 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 9a074776f70b..e2f6e5c928bb 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -226,6 +226,11 @@ struct flow_dissector { unsigned short int offset[FLOW_DISSECTOR_KEY_MAX]; }; +struct flow_keys_basic { + struct flow_dissector_key_control control; + struct flow_dissector_key_basic basic; +}; + struct flow_keys { struct flow_dissector_key_control control; #define FLOW_KEYS_HASH_START_FIELD basic @@ -244,7 +249,7 @@ __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; +extern struct flow_dissector flow_keys_basic_dissector; /* struct flow_keys_digest: * diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index d29f09bc5ff9..030d4ca177fb 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1253,7 +1253,7 @@ __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb) EXPORT_SYMBOL(skb_get_hash_perturb); u32 __skb_get_poff(const struct sk_buff *skb, void *data, - const struct flow_keys *keys, int hlen) + const struct flow_keys_basic *keys, int hlen) { u32 poff = keys->control.thoff; @@ -1314,9 +1314,9 @@ u32 __skb_get_poff(const struct sk_buff *skb, void *data, */ u32 skb_get_poff(const struct sk_buff *skb) { - struct flow_keys keys; + struct flow_keys_basic keys; - if (!skb_flow_dissect_flow_keys(skb, &keys, 0)) + if (!skb_flow_dissect_flow_keys_basic(skb, &keys, 0, 0, 0, 0, 0)) return 0; return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb)); @@ -1403,7 +1403,7 @@ static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = { }, }; -static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = { +static const struct flow_dissector_key flow_keys_basic_dissector_keys[] = { { .key_id = FLOW_DISSECTOR_KEY_CONTROL, .offset = offsetof(struct flow_keys, control), @@ -1417,7 +1417,8 @@ static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = { struct flow_dissector flow_keys_dissector __read_mostly; EXPORT_SYMBOL(flow_keys_dissector); -struct flow_dissector flow_keys_buf_dissector __read_mostly; +struct flow_dissector flow_keys_basic_dissector __read_mostly; +EXPORT_SYMBOL(flow_keys_basic_dissector); static int __init init_default_flow_dissectors(void) { @@ -1427,9 +1428,9 @@ static int __init init_default_flow_dissectors(void) skb_flow_dissector_init(&flow_keys_dissector_symmetric, flow_keys_dissector_symmetric_keys, ARRAY_SIZE(flow_keys_dissector_symmetric_keys)); - skb_flow_dissector_init(&flow_keys_buf_dissector, - flow_keys_buf_dissector_keys, - ARRAY_SIZE(flow_keys_buf_dissector_keys)); + skb_flow_dissector_init(&flow_keys_basic_dissector, + flow_keys_basic_dissector_keys, + ARRAY_SIZE(flow_keys_basic_dissector_keys)); return 0; } diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index eaeba9b99a73..ee28440f57c5 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -128,15 +128,15 @@ u32 eth_get_headlen(void *data, unsigned int len) { const unsigned int flags = FLOW_DISSECTOR_F_PARSE_1ST_FRAG; const struct ethhdr *eth = (const struct ethhdr *)data; - struct flow_keys keys; + struct flow_keys_basic keys; /* this should never happen, but better safe than sorry */ if (unlikely(len < sizeof(*eth))) return len; /* parse any remaining L2/L3 headers, check for L4 */ - if (!skb_flow_dissect_flow_keys_buf(&keys, data, eth->h_proto, - sizeof(*eth), len, flags)) + if (!skb_flow_dissect_flow_keys_basic(NULL, &keys, data, eth->h_proto, + sizeof(*eth), len, flags)) return max_t(u32, keys.control.thoff, sizeof(*eth)); /* parse for any L4 headers */