diff options
| author | Sabrina Dubroca <sd@queasysnail.net> | 2020-06-10 12:19:43 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-06-12 15:10:12 -0700 |
| commit | 2c7269b231194aae23fb90ab65842573a91acbc9 (patch) | |
| tree | 8b85edb1c7f094125445f5cea4e5d574c0d783e7 | |
| parent | 2c4779eff837f1035f6f9650d246905daadd9528 (diff) | |
| download | lwn-2c7269b231194aae23fb90ab65842573a91acbc9.tar.gz lwn-2c7269b231194aae23fb90ab65842573a91acbc9.zip | |
bpf: tcp: Recv() should return 0 when the peer socket is closed
If the peer is closed, we will never get more data, so
tcp_bpf_wait_data will get stuck forever. In case we passed
MSG_DONTWAIT to recv(), we get EAGAIN but we should actually get
0.
>From man 2 recv:
RETURN VALUE
When a stream socket peer has performed an orderly shutdown, the
return value will be 0 (the traditional "end-of-file" return).
This patch makes tcp_bpf_wait_data always return 1 when the peer
socket has been shutdown. Either we have data available, and it would
have returned 1 anyway, or there isn't, in which case we'll call
tcp_recvmsg which does the right thing in this situation.
Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/26038a28c21fea5d04d4bd4744c5686d3f2e5504.1591784177.git.sd@queasysnail.net
| -rw-r--r-- | net/ipv4/tcp_bpf.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 2b915aafda42..7aa68f4aae6c 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -245,6 +245,9 @@ static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock, DEFINE_WAIT_FUNC(wait, woken_wake_function); int ret = 0; + if (sk->sk_shutdown & RCV_SHUTDOWN) + return 1; + if (!timeo) return ret; |