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Message-Id: <20190322195903.162516-7-sdf@google.com>
Date: Fri, 22 Mar 2019 12:59:01 -0700
From: Stanislav Fomichev <sdf@...gle.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org
Cc: davem@...emloft.net, ast@...nel.org, daniel@...earbox.net,
simon.horman@...ronome.com, willemb@...gle.com,
peterpenkov96@...il.com, Stanislav Fomichev <sdf@...gle.com>
Subject: [RFC bpf-next v3 6/8] flow_dissector: handle no-skb use case
When called without skb, gather all required data from the
__skb_flow_dissect's arguments and use recently introduces
no-skb mode of bpf flow dissector.
Note: WARN_ON_ONCE(!net) will now trigger for eth_get_headlen users.
Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
---
net/core/flow_dissector.c | 54 +++++++++++++++++----------------------
1 file changed, 23 insertions(+), 31 deletions(-)
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 1e2e4a9330af..ec8ebafe333f 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -683,26 +683,6 @@ static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys,
}
}
-bool __skb_flow_bpf_dissect(struct bpf_prog *prog,
- const struct sk_buff *skb,
- struct flow_dissector *flow_dissector,
- struct bpf_flow_keys *flow_keys)
-{
- struct bpf_flow_dissector ctx = {
- .flow_keys = flow_keys,
- .skb = skb,
- .protocol = skb->protocol,
- .vlan_tci = skb->vlan_tci,
- .vlan_proto = skb->vlan_proto,
- .vlan_present = skb->vlan_present,
- .data = skb->data,
- .data_end = skb->data + skb_headlen(skb),
- };
-
- return bpf_flow_dissect(prog, &ctx, skb_network_offset(skb),
- skb_headlen(skb));
-}
-
bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,
int nhoff, int hlen)
{
@@ -754,6 +734,7 @@ bool __skb_flow_dissect(const struct net *net,
struct flow_dissector_key_icmp *key_icmp;
struct flow_dissector_key_tags *key_tags;
struct flow_dissector_key_vlan *key_vlan;
+ struct bpf_prog *attached = NULL;
enum flow_dissect_ret fdret;
enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX;
int num_hdrs = 0;
@@ -796,26 +777,37 @@ bool __skb_flow_dissect(const struct net *net,
target_container);
if (skb) {
- struct bpf_flow_keys flow_keys;
- struct bpf_prog *attached = NULL;
-
- rcu_read_lock();
if (!net) {
if (skb->dev)
net = dev_net(skb->dev);
else if (skb->sk)
net = sock_net(skb->sk);
- else
- WARN_ON_ONCE(1);
}
+ }
- if (net)
- attached = rcu_dereference(net->flow_dissector_prog);
+ WARN_ON_ONCE(!net);
+ if (net) {
+ rcu_read_lock();
+ attached = rcu_dereference(net->flow_dissector_prog);
if (attached) {
- ret = __skb_flow_bpf_dissect(attached, skb,
- flow_dissector,
- &flow_keys);
+ struct bpf_flow_keys flow_keys;
+ struct bpf_flow_dissector ctx = {
+ .flow_keys = &flow_keys,
+ .data = data,
+ .data_end = data + hlen,
+ .protocol = proto,
+ };
+
+ if (skb) {
+ ctx.skb = skb;
+ ctx.protocol = skb->protocol;
+ ctx.vlan_tci = skb->vlan_tci;
+ ctx.vlan_proto = skb->vlan_proto;
+ ctx.vlan_present = skb->vlan_present;
+ }
+
+ ret = bpf_flow_dissect(attached, &ctx, nhoff, hlen);
__skb_flow_bpf_to_target(&flow_keys, flow_dissector,
target_container);
rcu_read_unlock();
--
2.21.0.392.gf8f6787159e-goog
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