From: Ammar Faizi <ammarfaizi2@xxxxxxxxxxx>
Hi,
This is revision v2 of "Introducing t_bind_ephemeral_port() function".
After discussing an intermittent bind() issue with Dylan, I decided to
introduce a new helper function, t_bind_ephemeral_port().
## Problem:
We have many places where we need to bind() a socket to any unused port
number. To achieve that, the current approach does one of the following
mechanisms:
1) Randomly brute force the port number until the bind() syscall
succeeds.
2) Use a static port at compile time (randomly chosen too).
This is not reliable and it results in an intermittent issue (test
fails when the selected port is in use).
## Solution:
Setting @addr->sin_port to zero on a bind() syscall lets the kernel
choose a port number that is not in use. The caller then can know the
port number to be bound by invoking a getsockname() syscall after
bind() succeeds.
Wrap this procedure in a new function called t_bind_ephemeral_port().
The selected port will be returned into @addr->sin_port, the caller
can use it later to connect() or whatever they need.
## Patchset summary:
There are 12 patches in this series, summary:
1) Patch #1 introduces a new helper function t_bind_ephemeral_port().
2) Patch #2 to #6 get rid of the port number brute force mechanism.
3) Patch #7 to #12 stop using a static port number.
## Changelog
v1 -> v2:
- Fix variable placement in patch #2.
- Append Reviewed-by tags from Alviro.
- Append Tested-by tags from Alviro.
Link: https://lore.kernel.org/r/918facd1-78ba-2de7-693a-5f8c65ea2fcd@xxxxxxxxxxx
Cc: Dylan Yudaken <dylany@xxxxxx>
Cc: Facebook Kernel Team <kernel-team@xxxxxx>
Cc: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Ammar Faizi <ammarfaizi2@xxxxxxxxxxx>
---
Ammar Faizi (12):
test/helpers: Add `t_bind_ephemeral_port()` function
t/poll-link: Don't brute force the port number
t/socket-rw: Don't brute force the port number
t/socket-rw-eagain: Don't brute force the port number
t/socket-rw-offset: Don't brute force the port number
t/files-exit-hang-poll: Don't brute force the port number
t/socket: Don't use a static port number
t/connect: Don't use a static port number
t/shutdown: Don't use a static port number
t/recv-msgall: Don't use a static port number
t/232c93d07b74: Don't use a static port number
t/recv-msgall-stream: Don't use a static port number
test/232c93d07b74.c | 10 ++++------
test/accept.c | 5 +----
test/files-exit-hang-poll.c | 23 +++--------------------
test/helpers.c | 18 ++++++++++++++++++
test/helpers.h | 7 +++++++
test/poll-link.c | 27 +++++++++------------------
test/recv-msgall-stream.c | 22 ++++++++++------------
test/recv-msgall.c | 10 ++++------
test/shutdown.c | 7 +++----
test/socket-rw-eagain.c | 14 ++------------
test/socket-rw-offset.c | 13 ++-----------
test/socket-rw.c | 13 ++-----------
test/socket.c | 11 ++++++-----
13 files changed, 71 insertions(+), 109 deletions(-)
base-commit: b8c37f02662faa4f2b61840b123201ccc5678fb1
--
Ammar Faizi
