[PATCH v2 liburing 1/7] add t_create_socket_pair

[Dylan Yudaken <dylany@fb.com>]

This is a useful tool for making networking tests, and does not require a
hard coded port which is useful

Signed-off-by: Dylan Yudaken <dylany@fb.com>
---
 test/helpers.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++
 test/helpers.h |  5 +++
 2 files changed, 102 insertions(+)

diff --git a/test/helpers.c b/test/helpers.c
index 491822e..6fb1157 100644
--- a/test/helpers.c
+++ b/test/helpers.c
@@ -10,6 +10,10 @@
 #include <unistd.h>
 #include <sys/types.h>
 
+#include <arpa/inet.h>
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
+
 #include "helpers.h"
 #include "liburing.h"
 
@@ -143,3 +147,96 @@ enum t_setup_ret t_register_buffers(struct io_uring *ring,
 	fprintf(stderr, "buffer register failed: %s\n", strerror(-ret));
 	return ret;
 }
+
+int t_create_socket_pair(int fd[2], bool stream)
+{
+	int ret;
+	int type = stream ? SOCK_STREAM : SOCK_DGRAM;
+	int val;
+	struct sockaddr_in serv_addr;
+	struct sockaddr *paddr;
+	size_t paddrlen;
+
+	type |= SOCK_CLOEXEC;
+	fd[0] = socket(AF_INET, type, 0);
+	if (fd[0] < 0)
+		return errno;
+	fd[1] = socket(AF_INET, type, 0);
+	if (fd[1] < 0) {
+		ret = errno;
+		close(fd[0]);
+		return ret;
+	}
+
+	val = 1;
+	if (setsockopt(fd[0], SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)))
+		goto errno_cleanup;
+
+	memset(&serv_addr, 0, sizeof(serv_addr));
+	serv_addr.sin_family = AF_INET;
+	serv_addr.sin_port = 0;
+	inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr);
+
+	paddr = (struct sockaddr *)&serv_addr;
+	paddrlen = sizeof(serv_addr);
+
+	if (bind(fd[0], paddr, paddrlen)) {
+		fprintf(stderr, "bind failed\n");
+		goto errno_cleanup;
+	}
+
+	if (stream && listen(fd[0], 16)) {
+		fprintf(stderr, "listen failed\n");
+		goto errno_cleanup;
+	}
+
+	if (getsockname(fd[0], &serv_addr, (socklen_t *)&paddrlen)) {
+		fprintf(stderr, "getsockname failed\n");
+		goto errno_cleanup;
+	}
+	inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr);
+
+	if (connect(fd[1], &serv_addr, paddrlen)) {
+		fprintf(stderr, "connect failed\n");
+		goto errno_cleanup;
+	}
+
+	if (!stream) {
+		/* connect the other udp side */
+		if (getsockname(fd[1], &serv_addr, (socklen_t *)&paddrlen)) {
+			fprintf(stderr, "getsockname failed\n");
+			goto errno_cleanup;
+		}
+		inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr);
+
+		if (connect(fd[0], &serv_addr, paddrlen)) {
+			fprintf(stderr, "connect failed\n");
+			goto errno_cleanup;
+		}
+		return 0;
+	}
+
+	/* for stream case we must accept and cleanup the listen socket */
+
+	ret = accept(fd[0], NULL, NULL);
+	if (ret < 0)
+		goto errno_cleanup;
+
+	close(fd[0]);
+	fd[0] = ret;
+
+	val = 1;
+	if (stream && setsockopt(fd[0], SOL_TCP, TCP_NODELAY, &val, sizeof(val)))
+		goto errno_cleanup;
+	val = 1;
+	if (stream && setsockopt(fd[1], SOL_TCP, TCP_NODELAY, &val, sizeof(val)))
+		goto errno_cleanup;
+
+	return 0;
+
+errno_cleanup:
+	ret = errno;
+	close(fd[0]);
+	close(fd[1]);
+	return ret;
+}
diff --git a/test/helpers.h b/test/helpers.h
index 3179687..fbfd7d1 100644
--- a/test/helpers.h
+++ b/test/helpers.h
@@ -59,6 +59,11 @@ void t_create_file_pattern(const char *file, size_t size, char pattern);
  */
 struct iovec *t_create_buffers(size_t buf_num, size_t buf_size);
 
+/*
+ * Helper for creating connected socket pairs
+ */
+int t_create_socket_pair(int fd[2], bool stream);
+
 /*
  * Helper for setting up a ring and checking for user privs
  */
-- 
2.30.2