unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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flow_dissector: dissect tunnel info outside __skb_flow_dissect()

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Move dissection of tunnel info to outside of the main flow dissection
function, __skb_flow_dissect(). The sole user of this feature, the flower
classifier, is updated to call tunnel info dissection directly, using
skb_flow_dissect_tunnel_info().

This results in a slightly less complex implementation of
__skb_flow_dissect(), in particular removing logic from that call path
which is not used by the majority of users. The expense of this is borne by
the flower classifier which now has to make an extra call for tunnel info
dissection.

This patch should not result in any behavioural change.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Simon Horman 2017-12-04 11:31:48 +01:00 committed by David S. Miller
parent 96f8406162
commit 62b32379fd
3 changed files with 11 additions and 7 deletions
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5
include/linux/skbuff.h
View file

@ -1211,6 +1211,11 @@ static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys *flow,
data, proto, nhoff, hlen, flags);
}
void
skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container);
static inline __u32 skb_get_hash(struct sk_buff *skb)
{
if (!skb->l4_hash && !skb->sw_hash)

12
net/core/flow_dissector.c
View file

@ -133,10 +133,10 @@ skb_flow_dissect_set_enc_addr_type(enum flow_dissector_key_id type,
ctrl->addr_type = type;
}
static void
__skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container)
void
skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container)
{
struct ip_tunnel_info *info;
struct ip_tunnel_key *key;
@ -212,6 +212,7 @@ __skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
tp->dst = key->tp_dst;
}
}
EXPORT_SYMBOL(skb_flow_dissect_tunnel_info);
static enum flow_dissect_ret
__skb_flow_dissect_mpls(const struct sk_buff *skb,
@ -576,9 +577,6 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
FLOW_DISSECTOR_KEY_BASIC,
target_container);
__skb_flow_dissect_tunnel_info(skb, flow_dissector,
target_container);
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
struct ethhdr *eth = eth_hdr(skb);

1
net/sched/cls_flower.c
View file

@ -166,6 +166,7 @@ static int fl_classify(struct sk_buff *skb, const struct tcf_proto *tp,
* so do it rather here.
*/
skb_key.basic.n_proto = skb->protocol;
skb_flow_dissect_tunnel_info(skb, &head->dissector, &skb_key);
skb_flow_dissect(skb, &head->dissector, &skb_key, 0);
fl_set_masked_key(&skb_mkey, &skb_key, &head->mask);