From 872b1abb1ed47a691f465fb3d285f6cf6bcd8663 Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Tue, 1 Sep 2015 09:24:31 -0700 Subject: [PATCH] flow_dissector: Add flag to stop parsing when an IPv6 flow label is seen Add an input flag to flow dissector on rather dissection should be stopped when a flow label is encountered. Presumably, the flow label is derived from a sufficient hash of an inner transport packet so further dissection is not needed (that is ports are not included in the flow hash). Using the flow label instead of ports has the additional benefit that packet fragments should hash to same value as non-fragments for a flow (assuming that the same flow label is used). We set this flag by default in for skb_get_hash. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/net/flow_dissector.h | 1 + net/core/flow_dissector.c | 5 ++++- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index bb81e3b576e7..66dbc3498efb 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -126,6 +126,7 @@ enum flow_dissector_key_id { #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) struct flow_dissector_key { enum flow_dissector_key_id key_id; diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 94fd841f341f..094e34354627 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -239,6 +239,8 @@ ipv6: target_container); key_tags->flow_label = ntohl(flow_label); } + if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) + goto out_good; } if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) @@ -599,7 +601,8 @@ EXPORT_SYMBOL(flow_hash_from_keys); static inline u32 ___skb_get_hash(const struct sk_buff *skb, struct flow_keys *keys, u32 keyval) { - if (!skb_flow_dissect_flow_keys(skb, keys, 0)) + if (!skb_flow_dissect_flow_keys(skb, keys, + FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) return 0; return __flow_hash_from_keys(keys, keyval);