examples: add simple UDP client/server

In addition to showing basic UDP send/receive example, it helps to test
corner-case when dealing with 0-length UDP packets.

Change-Id: I08c0adf1cf9b6a6f1f7090b237d0497c2ec13cdf
Related: OS#2219

1 files changed, 35 insertions, 0 deletions

diff --git a/examples/udp-test-server.c b/examples/udp-test-server.c
new file mode 100644
index 0000000..444843a
--- /dev/null
+++ b/examples/udp-test-server.c
@@ -0,0 +1,35 @@
+#include "udp-test.h"
+
+int read_cb(struct osmo_dgram *conn)
+{
+	int bytes;
+	struct msgb *msg = print_recv(conn);
+
+	if (!msg)
+		return -1;
+
+	/* build reply: */
+	bytes = msgb_length(msg);
+
+	if (!mtrim(msg, 0, bytes))
+		return -1;
+
+	/* sent reply: */
+	osmo_dgram_send(conn, msg);
+
+	/* end test: */
+	if (bytes > NUM_MSG - 1)
+		please_dont_die = false;
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	if (!dgram_init(THOST, SPORT, CPORT, read_cb))
+		return EXIT_FAILURE;
+
+	main_loop(THOST, SPORT, CPORT);
+
+	return 0;
+}