Revision - 2c7269b - bpf: tcp: Recv() should return 0 when the peer socket is closed - origin: https://github.com/torvalds/linux

visit type:

https://github.com/torvalds/linux

17 May 2024, 11:00:25 UTC

Revision 2c7269b231194aae23fb90ab65842573a91acbc9 authored by Sabrina Dubroca on 10 June 2020, 10:19:43 UTC, committed by Alexei Starovoitov on 12 June 2020, 22:10:12 UTC

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

1 parent 2c4779e

Files
Changes

Permalinks

Tip revision: 2c7269b231194aae23fb90ab65842573a91acbc9 authored by Sabrina Dubroca on 10 June 2020, 10:19:43 UTC
bpf: tcp: Recv() should return 0 when the peer socket is closed

Tip revision: 2c7269b

File	Mode	Size
Documentation
LICENSES
arch
block
certs
crypto
drivers
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.clang-format	-rw-r--r--	15.8 KB
.cocciconfig	-rw-r--r--	59 bytes
.get_maintainer.ignore	-rw-r--r--	71 bytes
.gitattributes	-rw-r--r--	62 bytes
.gitignore	-rw-r--r--	1.7 KB
.mailmap	-rw-r--r--	15.4 KB
COPYING	-rw-r--r--	496 bytes
CREDITS	-rw-r--r--	97.4 KB
Kbuild	-rw-r--r--	1.3 KB
Kconfig	-rw-r--r--	595 bytes
MAINTAINERS	-rw-r--r--	542.1 KB
Makefile	-rw-r--r--	60.4 KB
README	-rw-r--r--	727 bytes

Showing with 0 additions and 0 deletions (0 / 0 diffs computed)

Computing file changes ...

https://github.com/torvalds/linux

bpf: tcp: Recv() should return 0 when the peer socket is closed

README