Commit a7ba4558 authored by Cong Wang's avatar Cong Wang Committed by Alexei Starovoitov
Browse files

sock_map: Introduce BPF_SK_SKB_VERDICT 



Reusing BPF_SK_SKB_STREAM_VERDICT is possible but its name is
confusing and more importantly we still want to distinguish them
from user-space. So we can just reuse the stream verdict code but
introduce a new type of eBPF program, skb_verdict. Users are not
allowed to attach stream_verdict and skb_verdict programs to the
same map.

Signed-off-by: default avatarCong Wang <cong.wang@bytedance.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-10-xiyou.wangcong@gmail.com
parent b0170552

include/linux/skmsg.h

+2 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ struct sk_psock_progs { 
	struct bpf_prog			*msg_parser;

	struct bpf_prog			*stream_parser;

	struct bpf_prog			*stream_verdict;

	struct bpf_prog			*skb_verdict;

};



enum sk_psock_state_bits {
@@ -487,6 +488,7 @@ static inline void psock_progs_drop(struct sk_psock_progs *progs) 
	psock_set_prog(&progs->msg_parser, NULL);

	psock_set_prog(&progs->stream_parser, NULL);

	psock_set_prog(&progs->stream_verdict, NULL);

	psock_set_prog(&progs->skb_verdict, NULL);

}



int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb);

include/uapi/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -957,6 +957,7 @@ enum bpf_attach_type { 
	BPF_XDP_CPUMAP,

	BPF_SK_LOOKUP,

	BPF_XDP,

	BPF_SK_SKB_VERDICT,

	__MAX_BPF_ATTACH_TYPE

};

kernel/bpf/syscall.c

+1 −0
Original line number Diff line number Diff line
@@ -2948,6 +2948,7 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type) 
		return BPF_PROG_TYPE_SK_MSG;

	case BPF_SK_SKB_STREAM_PARSER:

	case BPF_SK_SKB_STREAM_VERDICT:

	case BPF_SK_SKB_VERDICT:

		return BPF_PROG_TYPE_SK_SKB;

	case BPF_LIRC_MODE2:

		return BPF_PROG_TYPE_LIRC_MODE2;

net/core/skmsg.c

+3 −1
Original line number Diff line number Diff line
@@ -697,7 +697,7 @@ void sk_psock_drop(struct sock *sk, struct sk_psock *psock) 
	rcu_assign_sk_user_data(sk, NULL);

	if (psock->progs.stream_parser)

		sk_psock_stop_strp(sk, psock);

	else if (psock->progs.stream_verdict)

	else if (psock->progs.stream_verdict || psock->progs.skb_verdict)

		sk_psock_stop_verdict(sk, psock);

	write_unlock_bh(&sk->sk_callback_lock);
@@ -1024,6 +1024,8 @@ static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb, 
	}

	skb_set_owner_r(skb, sk);

	prog = READ_ONCE(psock->progs.stream_verdict);

	if (!prog)

		prog = READ_ONCE(psock->progs.skb_verdict);

	if (likely(prog)) {

		skb_dst_drop(skb);

		skb_bpf_redirect_clear(skb);

net/core/sock_map.c

+28 −0
Original line number Diff line number Diff line
@@ -156,6 +156,8 @@ static void sock_map_del_link(struct sock *sk, 
				strp_stop = true;

			if (psock->saved_data_ready && stab->progs.stream_verdict)

				verdict_stop = true;

			if (psock->saved_data_ready && stab->progs.skb_verdict)

				verdict_stop = true;

			list_del(&link->list);

			sk_psock_free_link(link);

		}
@@ -232,6 +234,7 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk) 
	struct sk_psock_progs *progs = sock_map_progs(map);

	struct bpf_prog *stream_verdict = NULL;

	struct bpf_prog *stream_parser = NULL;

	struct bpf_prog *skb_verdict = NULL;

	struct bpf_prog *msg_parser = NULL;

	struct sk_psock *psock;

	int ret;
@@ -268,6 +271,15 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk) 
		}

	}



	skb_verdict = READ_ONCE(progs->skb_verdict);

	if (skb_verdict) {

		skb_verdict = bpf_prog_inc_not_zero(skb_verdict);

		if (IS_ERR(skb_verdict)) {

			ret = PTR_ERR(skb_verdict);

			goto out_put_msg_parser;

		}

	}



no_progs:

	psock = sock_map_psock_get_checked(sk);

	if (IS_ERR(psock)) {
@@ -278,6 +290,9 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk) 
	if (psock) {

		if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) ||

		    (stream_parser  && READ_ONCE(psock->progs.stream_parser)) ||

		    (skb_verdict && READ_ONCE(psock->progs.skb_verdict)) ||

		    (skb_verdict && READ_ONCE(psock->progs.stream_verdict)) ||

		    (stream_verdict && READ_ONCE(psock->progs.skb_verdict)) ||

		    (stream_verdict && READ_ONCE(psock->progs.stream_verdict))) {

			sk_psock_put(sk, psock);

			ret = -EBUSY;
@@ -309,6 +324,9 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk) 
	} else if (!stream_parser && stream_verdict && !psock->saved_data_ready) {

		psock_set_prog(&psock->progs.stream_verdict, stream_verdict);

		sk_psock_start_verdict(sk,psock);

	} else if (!stream_verdict && skb_verdict && !psock->saved_data_ready) {

		psock_set_prog(&psock->progs.skb_verdict, skb_verdict);

		sk_psock_start_verdict(sk, psock);

	}

	write_unlock_bh(&sk->sk_callback_lock);

	return 0;
@@ -317,6 +335,9 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk) 
out_drop:

	sk_psock_put(sk, psock);

out_progs:

	if (skb_verdict)

		bpf_prog_put(skb_verdict);

out_put_msg_parser:

	if (msg_parser)

		bpf_prog_put(msg_parser);

out_put_stream_parser:
@@ -1442,8 +1463,15 @@ static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog, 
		break;

#endif

	case BPF_SK_SKB_STREAM_VERDICT:

		if (progs->skb_verdict)

			return -EBUSY;

		pprog = &progs->stream_verdict;

		break;

	case BPF_SK_SKB_VERDICT:

		if (progs->stream_verdict)

			return -EBUSY;

		pprog = &progs->skb_verdict;

		break;

	default:

		return -EOPNOTSUPP;

	}