From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=ALL_TRUSTED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NO_DNS_FOR_FROM,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.6 Received: from localhost.localdomain (unknown [182.2.38.99]) by gnuweeb.org (Postfix) with ESMTPSA id EDCD480C19; Fri, 2 Sep 2022 01:17:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1662081483; bh=1TE1GHzigpzQDCdNCY36kIyOGLAC2Vz4T/RbbxKeJqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WShROCcT1f546rnDZbY29JxyJdpF99IGa6W3wAJo4XN6J0eFQY/Dt0bevvjfi7ZY5 hqSHJb1Ju1GBlvebxAg0zsiw5+gNNY6/lQIx/KfemUuVbl+znUlTMJr+UDRQuES8Il 3QiCwsLtNCWchoV6mFR6mHvfvlbYUskXCY5C6b365mCSZznhYbIX889z7/qkHwWcih DCJ4I5Dgjehefbjq6zEtNweB9xv2U69DS4OVZDb55MhtDwd4yrfjvID0lQDRnAAnuM EVbFVj6snBjDjeYvHdSS/yp1Vq9NQmI8mnzkXgFEPVl1MCOaYJgquZvKcl2XF+yBgR 2gHBeD48ExopA== From: Ammar Faizi To: Jens Axboe Cc: Ammar Faizi , Dylan Yudaken , Facebook Kernel Team , Pavel Begunkov , io-uring Mailing List , GNU/Weeb Mailing List , Kanna Scarlet , Muhammad Rizki Subject: [RESEND PATCH liburing v1 01/12] test/helpers: Add `t_bind_ephemeral_port()` function Date: Fri, 2 Sep 2022 08:17:41 +0700 Message-Id: <20220902011548.2506938-2-ammar.faizi@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220902011548.2506938-1-ammar.faizi@intel.com> References: <20220902011548.2506938-1-ammar.faizi@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: 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@gnuweeb.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 @@ -19,24 +19,42 @@ /* * Helper for allocating memory in tests. */ void *t_malloc(size_t size) { void *ret; ret = malloc(size); assert(ret); return ret; } +/* + * 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 = 0; + if (bind(fd, (struct sockaddr *)addr, sizeof(*addr))) + return -errno; + + addrlen = sizeof(*addr); + assert(!getsockname(fd, (struct sockaddr *)addr, &addrlen)); + assert(addr->sin_port != 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 = posix_memalign(memptr, alignment, size); assert(!ret); } /* * Helper for allocating space for an array of nmemb elements diff --git a/test/helpers.h b/test/helpers.h index 6d5726c..9ad9947 100644 --- a/test/helpers.h +++ b/test/helpers.h @@ -13,24 +13,31 @@ extern "C" { enum t_setup_ret { T_SETUP_OK = 0, T_SETUP_SKIP, }; enum t_test_result { T_EXIT_PASS = 0, T_EXIT_FAIL = 1, T_EXIT_SKIP = 77, }; +/* + * 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); /* * Helper for allocating size bytes aligned on a boundary. */ void t_posix_memalign(void **memptr, size_t alignment, size_t size); -- Ammar Faizi