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Date: Mon, 28 Jan 2019 08:53:53 -0800
From: Stanislav Fomichev <sdf@...gle.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, ast@...nel.org, daniel@...earbox.net,
Stanislav Fomichev <sdf@...gle.com>,
Song Liu <songliubraving@...com>
Subject: [PATCH bpf-next v3 1/3] net/flow_dissector: move bpf case into __skb_flow_bpf_dissect
This way, we can reuse it for flow dissector in BPF_PROG_TEST_RUN.
No functional changes.
Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
Acked-by: Song Liu <songliubraving@...com>
---
include/linux/skbuff.h | 5 +++
net/core/flow_dissector.c | 92 +++++++++++++++++++++++----------------
2 files changed, 59 insertions(+), 38 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 93f56fddd92a..be762fc34ff3 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1221,6 +1221,11 @@ static inline int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
}
#endif
+struct bpf_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);
bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container,
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 9f2840510e63..bb1a54747d64 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -683,6 +683,46 @@ 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_skb_data_end cb_saved;
+ struct bpf_skb_data_end *cb;
+ u32 result;
+
+ /* Note that even though the const qualifier is discarded
+ * throughout the execution of the BPF program, all changes(the
+ * control block) are reverted after the BPF program returns.
+ * Therefore, __skb_flow_dissect does not alter the skb.
+ */
+
+ cb = (struct bpf_skb_data_end *)skb->cb;
+
+ /* Save Control Block */
+ memcpy(&cb_saved, cb, sizeof(cb_saved));
+ memset(cb, 0, sizeof(*cb));
+
+ /* Pass parameters to the BPF program */
+ memset(flow_keys, 0, sizeof(*flow_keys));
+ cb->qdisc_cb.flow_keys = flow_keys;
+ flow_keys->nhoff = skb_network_offset(skb);
+ flow_keys->thoff = flow_keys->nhoff;
+
+ bpf_compute_data_pointers((struct sk_buff *)skb);
+ result = BPF_PROG_RUN(prog, skb);
+
+ /* Restore state */
+ memcpy(cb, &cb_saved, sizeof(cb_saved));
+
+ flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, 0, skb->len);
+ flow_keys->thoff = clamp_t(u16, flow_keys->thoff,
+ flow_keys->nhoff, skb->len);
+
+ return result == BPF_OK;
+}
+
/**
* __skb_flow_dissect - extract the flow_keys struct and return it
* @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
@@ -714,7 +754,6 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector_key_vlan *key_vlan;
enum flow_dissect_ret fdret;
enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX;
- struct bpf_prog *attached = NULL;
int num_hdrs = 0;
u8 ip_proto = 0;
bool ret;
@@ -754,53 +793,30 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
FLOW_DISSECTOR_KEY_BASIC,
target_container);
- rcu_read_lock();
if (skb) {
+ struct bpf_flow_keys flow_keys;
+ struct bpf_prog *attached = NULL;
+
+ rcu_read_lock();
+
if (skb->dev)
attached = rcu_dereference(dev_net(skb->dev)->flow_dissector_prog);
else if (skb->sk)
attached = rcu_dereference(sock_net(skb->sk)->flow_dissector_prog);
else
WARN_ON_ONCE(1);
- }
- if (attached) {
- /* Note that even though the const qualifier is discarded
- * throughout the execution of the BPF program, all changes(the
- * control block) are reverted after the BPF program returns.
- * Therefore, __skb_flow_dissect does not alter the skb.
- */
- struct bpf_flow_keys flow_keys = {};
- struct bpf_skb_data_end cb_saved;
- struct bpf_skb_data_end *cb;
- u32 result;
-
- cb = (struct bpf_skb_data_end *)skb->cb;
-
- /* Save Control Block */
- memcpy(&cb_saved, cb, sizeof(cb_saved));
- memset(cb, 0, sizeof(cb_saved));
- /* Pass parameters to the BPF program */
- cb->qdisc_cb.flow_keys = &flow_keys;
- flow_keys.nhoff = nhoff;
- flow_keys.thoff = nhoff;
-
- bpf_compute_data_pointers((struct sk_buff *)skb);
- result = BPF_PROG_RUN(attached, skb);
-
- /* Restore state */
- memcpy(cb, &cb_saved, sizeof(cb_saved));
-
- flow_keys.nhoff = clamp_t(u16, flow_keys.nhoff, 0, skb->len);
- flow_keys.thoff = clamp_t(u16, flow_keys.thoff,
- flow_keys.nhoff, skb->len);
-
- __skb_flow_bpf_to_target(&flow_keys, flow_dissector,
- target_container);
+ if (attached) {
+ ret = __skb_flow_bpf_dissect(attached, skb,
+ flow_dissector,
+ &flow_keys);
+ __skb_flow_bpf_to_target(&flow_keys, flow_dissector,
+ target_container);
+ rcu_read_unlock();
+ return ret;
+ }
rcu_read_unlock();
- return result == BPF_OK;
}
- rcu_read_unlock();
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
--
2.20.1.495.gaa96b0ce6b-goog
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