diff options
| author | Martin KaFai Lau <kafai@fb.com> | 2019-03-12 10:23:04 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-03-13 12:04:35 -0700 |
| commit | dbafd7ddd62369b2f3926ab847cbf8fc40e800b7 (patch) | |
| tree | 35ce32dfc258798b98bb4d7e4253f34bb4cf43e1 /include/uapi | |
| parent | 1b986589680a2a5b6fc1ac196ea69925a93d9dd9 (diff) | |
| download | linux-dbafd7ddd62369b2f3926ab847cbf8fc40e800b7.tar.bz2 | |
bpf: Add bpf_get_listener_sock(struct bpf_sock *sk) helper
Add a new helper "struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)"
which returns a bpf_sock in TCP_LISTEN state. It will trace back to
the listener sk from a request_sock if possible. It returns NULL
for all other cases.
No reference is taken because the helper ensures the sk is
in SOCK_RCU_FREE (where the TCP_LISTEN sock should be in).
Hence, bpf_sk_release() is unnecessary and the verifier does not
allow bpf_sk_release(listen_sk) to be called either.
The following is also allowed because the bpf_prog is run under
rcu_read_lock():
sk = bpf_sk_lookup_tcp();
/* if (!sk) { ... } */
listen_sk = bpf_get_listener_sock(sk);
/* if (!listen_sk) { ... } */
bpf_sk_release(sk);
src_port = listen_sk->src_port; /* Allowed */
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/bpf.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3c38ac9a92a7..983b25cb608d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2366,6 +2366,14 @@ union bpf_attr { * current value is ect (ECN capable). Works with IPv6 and IPv4. * Return * 1 if set, 0 if not set. + * + * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk) + * Description + * Return a **struct bpf_sock** pointer in TCP_LISTEN state. + * bpf_sk_release() is unnecessary and not allowed. + * Return + * A **struct bpf_sock** pointer on success, or NULL in + * case of failure. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2465,7 +2473,8 @@ union bpf_attr { FN(spin_unlock), \ FN(sk_fullsock), \ FN(tcp_sock), \ - FN(skb_ecn_set_ce), + FN(skb_ecn_set_ce), \ + FN(get_listener_sock), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call |