From 01e5611ec3912f02fb683305db8913f8eca15fee Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 17 Jul 2024 14:52:22 +1000 Subject: doc: Test behaviour of closing duplicate UDP sockets To simplify lifetime management of "listening" UDP sockets, UDP flow support needs to duplicate existing bound sockets. Those duplicates will be close()d when their corresponding flow expires, but we expect the original to still receive datagrams as always. That is, we expect the close() on the duplicate to remove the duplicated fd, but not to close the underlying UDP socket. Add a test program to doc/platform-requirements to verify this requirement. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- doc/platform-requirements/.gitignore | 1 + doc/platform-requirements/Makefile | 4 +- doc/platform-requirements/udp-close-dup.c | 105 ++++++++++++++++++++++++++++++ 3 files changed, 108 insertions(+), 2 deletions(-) create mode 100644 doc/platform-requirements/udp-close-dup.c diff --git a/doc/platform-requirements/.gitignore b/doc/platform-requirements/.gitignore index 555031d..3b5a10a 100644 --- a/doc/platform-requirements/.gitignore +++ b/doc/platform-requirements/.gitignore @@ -1,2 +1,3 @@ /reuseaddr-priority /recv-zero +/udp-close-dup diff --git a/doc/platform-requirements/Makefile b/doc/platform-requirements/Makefile index 82aaac2..6a7d374 100644 --- a/doc/platform-requirements/Makefile +++ b/doc/platform-requirements/Makefile @@ -3,8 +3,8 @@ # Copyright Red Hat # Author: David Gibson -TARGETS = reuseaddr-priority recv-zero -SRCS = reuseaddr-priority.c recv-zero.c +TARGETS = reuseaddr-priority recv-zero udp-close-dup +SRCS = reuseaddr-priority.c recv-zero.c udp-close-dup.c CFLAGS = -Wall all: cppcheck clang-tidy $(TARGETS:%=check-%) diff --git a/doc/platform-requirements/udp-close-dup.c b/doc/platform-requirements/udp-close-dup.c new file mode 100644 index 0000000..99060fc --- /dev/null +++ b/doc/platform-requirements/udp-close-dup.c @@ -0,0 +1,105 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +/* udp-close-dup.c + * + * Verify that closing one dup() of a UDP socket won't stop other dups from + * receiving packets. + * + * Copyright Red Hat + * Author: David Gibson + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "common.h" + +#define DSTPORT 13257U + +/* 127.0.0.1:DSTPORT */ +static const struct sockaddr_in lo_dst = SOCKADDR_INIT(INADDR_LOOPBACK, DSTPORT); + +enum dup_method { + DUP_DUP, + DUP_FCNTL, + NUM_METHODS, +}; + +static void test_close_dup(enum dup_method method) +{ + long token; + int s1, s2, send_s; + ssize_t rc; + + s1 = sock_reuseaddr(); + if (bind(s1, (struct sockaddr *)&lo_dst, sizeof(lo_dst)) < 0) + die("bind(): %s\n", strerror(errno)); + + send_s = sock_reuseaddr(); + if (connect(send_s, (struct sockaddr *)&lo_dst, sizeof(lo_dst)) < 0) + die("connect(): %s\n", strerror(errno)); + + /* Receive before duplicating */ + token = random(); + send_token(send_s, token); + recv_token(s1, token); + + switch (method) { + case DUP_DUP: + /* NOLINTNEXTLINE(android-cloexec-dup) */ + s2 = dup(s1); + if (s2 < 0) + die("dup(): %s\n", strerror(errno)); + break; + case DUP_FCNTL: + s2 = fcntl(s1, F_DUPFD_CLOEXEC, 0); + if (s2 < 0) + die("F_DUPFD_CLOEXEC: %s\n", strerror(errno)); + break; + default: + die("Bad method\n"); + } + + /* Receive via original handle */ + token = random(); + send_token(send_s, token); + recv_token(s1, token); + + /* Receive via duplicated handle */ + token = random(); + send_token(send_s, token); + recv_token(s2, token); + + /* Close duplicate */ + rc = close(s2); + if (rc < 0) + die("close() dup: %s\n", strerror(errno)); + + /* Receive after closing duplicate */ + token = random(); + send_token(send_s, token); + recv_token(s1, token); +} + +int main(int argc, char *argv[]) +{ + enum dup_method method; + + (void)argc; + (void)argv; + + for (method = 0; method < NUM_METHODS; method++) + test_close_dup(method); + + printf("Closing dup()ed UDP sockets seems to work as expected\n"); + + exit(0); +} -- cgit v1.2.3