net/flow_dissector: move bpf case into __skb_flow_bpf_dissect (c8aa7038) · Commits · 戴 / test

include/linux/skbuff.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -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,

net/core/flow_dissector.c

+54 −38

Original line number	Diff line number	Diff line
		@@ -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);

		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 result == BPF_OK;
		return ret;
		}
		rcu_read_unlock();
		}

		if (dissector_uses_key(flow_dissector,
		FLOW_DISSECTOR_KEY_ETH_ADDRS)) {

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