test/accept-non-empty: add accept IORING_CQE_F_SOCK_NONEMPTY test

This tests whether we correctly get IORING_CQE_F_SOCK_NONEMPTY set
on an accept request, if there are more connections pending after
the current one has been accepted.

The test is currently gated on IORING_FEAT_RECVSEND_BUNDLE, as that
got added to the kernel at the same time as this feature. Not the
prettiest, but it's what we have for now...

Signed-off-by: Jens Axboe <axboe@kernel.dk>

test/Makefile

@@ -46,6 +46,7 @@ test_srcs := \
 	a4c0b3decb33.c \
 	accept.c \
 	accept-link.c \
+	accept-non-empty.c \
 	accept-reuse.c \
 	accept-test.c \
 	across-fork.c \

test/accept-non-empty.c

@@ -0,0 +1,256 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Check that kernels that support it will return IORING_CQE_F_SOCK_NONEMPTY
+ * on accepts requests where more connections are pending.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/un.h>
+#include <netinet/tcp.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <pthread.h>
+
+#include "liburing.h"
+#include "helpers.h"
+
+static int no_more_accept;
+
+#define MAX_ACCEPTS	8
+
+struct data {
+	pthread_t thread;
+	pthread_barrier_t barrier;
+	pthread_barrier_t conn_barrier;
+	int connects;
+};
+
+static int start_accept_listen(int port_off, int extra_flags)
+{
+	struct sockaddr_in addr;
+	int32_t val = 1;
+	int fd, ret;
+
+	fd = socket(AF_INET, SOCK_STREAM | extra_flags, IPPROTO_TCP);
+
+	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val));
+	assert(ret != -1);
+	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+	assert(ret != -1);
+
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(0x1235 + port_off);
+	addr.sin_addr.s_addr = inet_addr("127.0.0.1");
+
+	ret = bind(fd, (struct sockaddr *) &addr, sizeof(addr));
+	assert(ret != -1);
+	ret = listen(fd, 20000);
+	assert(ret != -1);
+
+	return fd;
+}
+
+static int test_maccept(struct data *d, int flags, int fixed)
+{
+	struct io_uring_params p = { };
+	struct io_uring ring;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	int err = 0, fd, ret, i, *fds;
+
+	p.flags = flags;
+	ret = io_uring_queue_init_params(8, &ring, &p);
+	if (ret == -EINVAL) {
+		return T_EXIT_SKIP;
+	} else if (ret < 0) {
+		fprintf(stderr, "ring setup failure: %d\n", ret);
+		return T_EXIT_FAIL;
+	}
+
+	if (!(p.features & IORING_FEAT_RECVSEND_BUNDLE)) {
+		no_more_accept = 1;
+		return 0;
+	}
+
+	fds = malloc(MAX_ACCEPTS * sizeof(int));
+	memset(fds, -1, MAX_ACCEPTS * sizeof(int));
+
+	if (fixed) {
+		io_uring_register_ring_fd(&ring);
+
+		ret = io_uring_register_files(&ring, fds, MAX_ACCEPTS);
+		if (ret) {
+			fprintf(stderr, "file reg %d\n", ret);
+			return -1;
+		}
+	}
+
+	fd = start_accept_listen(0, 0);
+
+	pthread_barrier_wait(&d->barrier);
+
+	if (d->connects > 1)
+		pthread_barrier_wait(&d->conn_barrier);
+
+	for (i = 0; i < d->connects; i++) {
+		sqe = io_uring_get_sqe(&ring);
+		if (fixed)
+			io_uring_prep_accept_direct(sqe, fd, NULL, NULL, 0, i);
+		else
+			io_uring_prep_accept(sqe, fd, NULL, NULL, 0);
+
+		ret = io_uring_submit_and_wait(&ring, 1);
+		assert(ret != -1);
+
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		assert(!ret);
+		if (cqe->res < 0) {
+			fprintf(stderr, "res=%d\n", cqe->res);
+			break;
+		}
+		fds[i] = cqe->res;
+		if (d->connects == 1) {
+			if (cqe->flags & IORING_CQE_F_SOCK_NONEMPTY) {
+				fprintf(stderr, "Non-empty sock on single?\n");
+				err = 1;
+				break;
+			}
+		} else {
+			int last = i + 1 == d->connects;
+
+			if (last && cqe->flags & IORING_CQE_F_SOCK_NONEMPTY) {
+				fprintf(stderr, "Non-empty sock on last?\n");
+				err = 1;
+				break;
+			} else if (!last && !(cqe->flags & IORING_CQE_F_SOCK_NONEMPTY)) {
+				fprintf(stderr, "Empty on multi connect?\n");
+				err = 1;
+				break;
+			}
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	close(fd);
+	if (!fixed) {
+		for (i = 0; i < MAX_ACCEPTS; i++)
+			if (fds[i] != -1)
+				close(fds[i]);
+	}
+	free(fds);
+	io_uring_queue_exit(&ring);
+	return err;
+}
+
+static void *connect_fn(void *data)
+{
+	struct sockaddr_in addr = { };
+	struct data *d = data;
+	int i;
+
+	pthread_barrier_wait(&d->barrier);
+
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(0x1235);
+	addr.sin_addr.s_addr = inet_addr("127.0.0.1");
+
+	for (i = 0; i < d->connects; i++) {
+		int s;
+
+		s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+		if (s < 0) {
+			perror("socket");
+			break;
+		}
+		if (connect(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+			perror("connect");
+			break;
+		}
+	}
+
+	if (d->connects > 1)
+		pthread_barrier_wait(&d->conn_barrier);
+
+	return NULL;
+}
+
+static void setup_thread(struct data *d, int nconns)
+{
+	d->connects = nconns;
+	pthread_barrier_init(&d->barrier, NULL, 2);
+	pthread_barrier_init(&d->conn_barrier, NULL, 2);
+	pthread_create(&d->thread, NULL, connect_fn, d);
+}
+
+static int test(int flags, int fixed)
+{
+	struct data d;
+	void *tret;
+	int ret;
+
+	setup_thread(&d, 1);
+	ret = test_maccept(&d, flags, fixed);
+	if (ret) {
+		fprintf(stderr, "test conns=1 failed\n");
+		return ret;
+	}
+	if (no_more_accept)
+		return T_EXIT_SKIP;
+
+	pthread_join(d.thread, &tret);
+
+	setup_thread(&d, MAX_ACCEPTS);
+	ret = test_maccept(&d, flags, fixed);
+	if (ret) {
+		fprintf(stderr, "test conns=MAX failed\n");
+		return ret;
+	}
+
+	pthread_join(d.thread, &tret);
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	if (argc > 1)
+		return T_EXIT_SKIP;
+
+	ret = test(0, 0);
+	if (no_more_accept)
+		return T_EXIT_SKIP;
+	if (ret) {
+		fprintf(stderr, "test 0 0 failed\n");
+		return ret;
+	}
+
+	ret = test(IORING_SETUP_SINGLE_ISSUER|IORING_SETUP_DEFER_TASKRUN, 0);
+	if (ret) {
+		fprintf(stderr, "test DEFER 0 failed\n");
+		return ret;
+	}
+
+	ret = test(0, 1);
+	if (ret) {
+		fprintf(stderr, "test 0 1 failed\n");
+		return ret;
+	}
+
+	ret = test(IORING_SETUP_SINGLE_ISSUER|IORING_SETUP_DEFER_TASKRUN, 1);
+	if (ret) {
+		fprintf(stderr, "test DEFER 1 failed\n");
+		return ret;
+	}
+
+	return 0;
+}