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Commit b7a1848e authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann
Browse files

bpf: add BPF_PROG_TEST_RUN support for flow dissector 



The input is packet data, the output is struct bpf_flow_key. This should
make it easy to test flow dissector programs without elaborate
setup.

Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent c8aa7038

include/linux/bpf.h

+3 −0
Original line number Diff line number Diff line
@@ -404,6 +404,9 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, 
			  union bpf_attr __user *uattr);

int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,

			  union bpf_attr __user *uattr);

int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,

				     const union bpf_attr *kattr,

				     union bpf_attr __user *uattr);



/* an array of programs to be executed under rcu_lock.

 *

net/bpf/test_run.c

+82 −0
Original line number Diff line number Diff line
@@ -240,3 +240,85 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, 
	kfree(data);

	return ret;

}



int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,

				     const union bpf_attr *kattr,

				     union bpf_attr __user *uattr)

{

	u32 size = kattr->test.data_size_in;

	u32 repeat = kattr->test.repeat;

	struct bpf_flow_keys flow_keys;

	u64 time_start, time_spent = 0;

	struct bpf_skb_data_end *cb;

	u32 retval, duration;

	struct sk_buff *skb;

	struct sock *sk;

	void *data;

	int ret;

	u32 i;



	if (prog->type != BPF_PROG_TYPE_FLOW_DISSECTOR)

		return -EINVAL;



	data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,

			     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));

	if (IS_ERR(data))

		return PTR_ERR(data);



	sk = kzalloc(sizeof(*sk), GFP_USER);

	if (!sk) {

		kfree(data);

		return -ENOMEM;

	}

	sock_net_set(sk, current->nsproxy->net_ns);

	sock_init_data(NULL, sk);



	skb = build_skb(data, 0);

	if (!skb) {

		kfree(data);

		kfree(sk);

		return -ENOMEM;

	}

	skb->sk = sk;



	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);

	__skb_put(skb, size);

	skb->protocol = eth_type_trans(skb,

				       current->nsproxy->net_ns->loopback_dev);

	skb_reset_network_header(skb);



	cb = (struct bpf_skb_data_end *)skb->cb;

	cb->qdisc_cb.flow_keys = &flow_keys;



	if (!repeat)

		repeat = 1;



	time_start = ktime_get_ns();

	for (i = 0; i < repeat; i++) {

		preempt_disable();

		rcu_read_lock();

		retval = __skb_flow_bpf_dissect(prog, skb,

						&flow_keys_dissector,

						&flow_keys);

		rcu_read_unlock();

		preempt_enable();



		if (need_resched()) {

			if (signal_pending(current))

				break;

			time_spent += ktime_get_ns() - time_start;

			cond_resched();

			time_start = ktime_get_ns();

		}

	}

	time_spent += ktime_get_ns() - time_start;

	do_div(time_spent, repeat);

	duration = time_spent > U32_MAX ? U32_MAX : (u32)time_spent;



	ret = bpf_test_finish(kattr, uattr, &flow_keys, sizeof(flow_keys),

			      retval, duration);



	kfree_skb(skb);

	kfree(sk);

	return ret;

}

net/core/filter.c

+1 −0
Original line number Diff line number Diff line
@@ -7711,6 +7711,7 @@ const struct bpf_verifier_ops flow_dissector_verifier_ops = { 
};



const struct bpf_prog_ops flow_dissector_prog_ops = {

	.test_run		= bpf_prog_test_run_flow_dissector,

};



int sk_detach_filter(struct sock *sk)