From fbff949e3bc7f3f7d9e8b3ef4855ec7138276a25 Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Tue, 12 May 2015 14:56:15 +0200 Subject: [PATCH] flow_dissector: introduce programable flow_dissector Introduce dissector infrastructure which allows user to specify which parts of skb he wants to dissect. Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/flow_dissector.h | 61 ++++++++++++++++++++++++++++++++++++++++++++ net/core/flow_dissector.c | 48 ++++++++++++++++++++++++++++++++++ 2 files changed, 109 insertions(+) diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index e4ee761ca8c0..20239e807f77 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -1,6 +1,64 @@ #ifndef _NET_FLOW_DISSECTOR_H #define _NET_FLOW_DISSECTOR_H +/** + * 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; +}; + +/** + * 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_addrs { + /* (src,dst) must be grouped, in the same way than in IP header */ + __be32 src; + __be32 dst; +}; + +/** + * flow_dissector_key_tp_ports: + * @ports: port numbers of Transport header + * port16[0]: src port number + * port16[1]: dst port number + */ +struct flow_dissector_key_ports { + union { + __be32 ports; + __be16 port16[2]; + }; +}; + +enum flow_dissector_key_id { + 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_MAX, +}; + +struct flow_dissector_key { + enum flow_dissector_key_id key_id; + size_t offset; /* offset of struct flow_dissector_key_* + in target the struct */ +}; + +struct flow_dissector { + unsigned int used_keys; /* each bit repesents presence of one key id */ + unsigned short int offset[FLOW_DISSECTOR_KEY_MAX]; +}; + /* struct flow_keys: * @src: source ip address in case of IPv4 * For IPv6 it contains 32bit hash of src address @@ -27,6 +85,9 @@ struct flow_keys { u8 ip_proto; }; +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_keys *flow, void *data, __be16 proto, int nhoff, int hlen); diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index d885e282908e..6883e22b8fc4 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1,3 +1,4 @@ +#include #include #include #include @@ -15,6 +16,53 @@ #include #include +static bool skb_flow_dissector_uses_key(struct flow_dissector *flow_dissector, + enum flow_dissector_key_id key_id) +{ + return flow_dissector->used_keys & (1 << key_id); +} + +static void skb_flow_dissector_set_key(struct flow_dissector *flow_dissector, + enum flow_dissector_key_id key_id) +{ + flow_dissector->used_keys |= (1 << key_id); +} + +static void *skb_flow_dissector_target(struct flow_dissector *flow_dissector, + enum flow_dissector_key_id key_id, + void *target_container) +{ + return ((char *) target_container) + flow_dissector->offset[key_id]; +} + +void skb_flow_dissector_init(struct flow_dissector *flow_dissector, + const struct flow_dissector_key *key, + unsigned int key_count) +{ + unsigned int i; + + memset(flow_dissector, 0, sizeof(*flow_dissector)); + + for (i = 0; i < key_count; i++, key++) { + /* User should make sure that every key target offset is withing + * boundaries of unsigned short. + */ + BUG_ON(key->offset > USHRT_MAX); + BUG_ON(skb_flow_dissector_uses_key(flow_dissector, + key->key_id)); + + skb_flow_dissector_set_key(flow_dissector, key->key_id); + 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. + */ + BUG_ON(!skb_flow_dissector_uses_key(flow_dissector, + FLOW_DISSECTOR_KEY_BASIC)); +} +EXPORT_SYMBOL(skb_flow_dissector_init); + /* copy saddr & daddr, possibly using 64bit load/store * Equivalent to : flow->src = iph->saddr; * flow->dst = iph->daddr; -- 2.11.0