[PATCH net-next 1/4] flow_keys: include thoff into flow_keys for later usage

[Daniel Borkmann <dborkman@redhat.com>]

In skb_flow_dissect(), we perform a dissection of a skbuff. Since we're
doing the work here anyway, also store thoff for a later usage, e.g. in
the BPF filter. We need to reorder choke_skb_cb a bit, though. Also, by
having thoff 16 Bit, we do not need to pack flow_keys.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
---
 include/net/flow_keys.h   | 1 +
 net/core/flow_dissector.c | 5 ++++-
 net/sched/sch_choke.c     | 4 ++--
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h
index 80461c1..bb8271d 100644
--- a/include/net/flow_keys.h
+++ b/include/net/flow_keys.h
@@ -9,6 +9,7 @@ struct flow_keys {
 		__be32 ports;
 		__be16 port16[2];
 	};
+	u16 thoff;
 	u8 ip_proto;
 };
 
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index f8d9e03..eb9dde1 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -23,7 +23,8 @@ static void iph_to_flow_copy_addrs(struct flow_keys *flow, const struct iphdr *i
 
 bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
 {
-	int poff, nhoff = skb_network_offset(skb);
+	int poff;
+	u16 nhoff = skb_network_offset(skb);
 	u8 ip_proto;
 	__be16 proto = skb->protocol;
 
@@ -151,6 +152,8 @@ ipv6:
 			flow->ports = *ports;
 	}
 
+	flow->thoff = nhoff;
+
 	return true;
 }
 EXPORT_SYMBOL(skb_flow_dissect);
diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index cc37dd5..9854c2b 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -141,9 +141,9 @@ static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx)
 }
 
 struct choke_skb_cb {
-	u16			classid;
-	u8			keys_valid;
 	struct flow_keys	keys;
+	u8			keys_valid;
+	u16			classid;
 };
 
 static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb)
-- 
1.7.11.7