From nobody Mon Apr 6 23:08:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7E75ECAAD3 for ; Fri, 2 Sep 2022 01:00:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234915AbiIBBAb (ORCPT ); Thu, 1 Sep 2022 21:00:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232835AbiIBBAX (ORCPT ); Thu, 1 Sep 2022 21:00:23 -0400 Received: from gnuweeb.org (gnuweeb.org [51.81.211.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23CC637FBE for ; Thu, 1 Sep 2022 18:00:22 -0700 (PDT) Received: from localhost.localdomain (unknown [182.2.38.99]) by gnuweeb.org (Postfix) with ESMTPSA id BE9B480C0B; Fri, 2 Sep 2022 01:00:17 +0000 (UTC) X-GW-Data: lPqxHiMPbJw1wb7CM9QUryAGzr0yq5atzVDdxTR0iA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1662080421; bh=xlT8ZBYljMLF/iDvL7d497O6CwzFosNpW9mk4b4aomw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ClxGCIIcEIszw+3JW53Bqjpf88KCRC7NZBZ0GUYOvPwutLy3eWMMGhkQp6/LxlhiQ CI3vjnnY1W98dPS+2nkcqkhZCTXJVsyxXjdngOIQk3j37k5eQyCVX/EQTeD0fvhXUd fvyocMgjLvUGoZu0GRoS0+Se22Pg83dRANo/TisiH+5epjtUJZI/Og47BwUoXczzPs 3An1cA8CyRO+3+FcUqRvX7/WFGVDHEEi2wM4ekX0dyt+kBny1atdRphv/FgqN/cpNJ X8U2bB7up2wyxRNMzUHSDW7r2q0GCb0Gv7M9j1twHtJ2O2MsvQaLTAgzeERIGrrAxQ GzhioQ3koBIxA== From: Ammar Faizi To: Jens Axboe Cc: Ammar Faizi , Dylan Yudaken , Facebook Kernel Team , Pavel Begunkov , Kanna Scarlet , Muhammad Rizki , GNU/Weeb Mailing List , io-uring Mailing List , Linux Kernel Mailing List Subject: [PATCH liburing v1 01/12] test/helpers: Add `t_bind_ephemeral_port()` function Date: Fri, 2 Sep 2022 07:59:35 +0700 Message-Id: <20220902005825.2484023-2-ammar.faizi@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220902005825.2484023-1-ammar.faizi@intel.com> References: <20220902005825.2484023-1-ammar.faizi@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Ammar Faizi This is a prep patch to fix an intermittent issue with the port number. 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). 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. Link: https://lore.kernel.org/r/918facd1-78ba-2de7-693a-5f8c65ea2fcd@gnuwee= b.org Cc: Dylan Yudaken Cc: Facebook Kernel Team Cc: Pavel Begunkov Signed-off-by: Ammar Faizi --- test/helpers.c | 18 ++++++++++++++++++ test/helpers.h | 7 +++++++ 2 files changed, 25 insertions(+) diff --git a/test/helpers.c b/test/helpers.c index 0146533..4d5c402 100644 --- a/test/helpers.c +++ b/test/helpers.c @@ -18,26 +18,44 @@ #include "liburing.h" =20 /* * Helper for allocating memory in tests. */ void *t_malloc(size_t size) { void *ret; ret =3D malloc(size); assert(ret); return ret; } =20 +/* + * Helper for binding socket to an ephemeral port. + * The port number to be bound is returned in @addr->sin_port. + */ +int t_bind_ephemeral_port(int fd, struct sockaddr_in *addr) +{ + socklen_t addrlen; + + addr->sin_port =3D 0; + if (bind(fd, (struct sockaddr *)addr, sizeof(*addr))) + return -errno; + + addrlen =3D sizeof(*addr); + assert(!getsockname(fd, (struct sockaddr *)addr, &addrlen)); + assert(addr->sin_port !=3D 0); + return 0; +} + /* * Helper for allocating size bytes aligned on a boundary. */ void t_posix_memalign(void **memptr, size_t alignment, size_t size) { int ret; ret =3D posix_memalign(memptr, alignment, size); assert(!ret); } =20 /* * Helper for allocating space for an array of nmemb elements * with size bytes for each element. diff --git a/test/helpers.h b/test/helpers.h index 6d5726c..9ad9947 100644 --- a/test/helpers.h +++ b/test/helpers.h @@ -12,26 +12,33 @@ extern "C" { #include "liburing.h" =20 enum t_setup_ret { T_SETUP_OK =3D 0, T_SETUP_SKIP, }; =20 enum t_test_result { T_EXIT_PASS =3D 0, T_EXIT_FAIL =3D 1, T_EXIT_SKIP =3D 77, }; =20 +/* + * Helper for binding socket to an ephemeral port. + * The port number to be bound is returned in @addr->sin_port. + */ +int t_bind_ephemeral_port(int fd, struct sockaddr_in *addr); + + /* * Helper for allocating memory in tests. */ void *t_malloc(size_t size); =20 =20 /* * Helper for allocating size bytes aligned on a boundary. */ void t_posix_memalign(void **memptr, size_t alignment, size_t size); =20 =20 /* --=20 Ammar Faizi