[PATCH] libosmo-netif[master]: examples: add simple UDP client/server

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Max gerrit-no-reply at lists.osmocom.org
Fri Oct 13 16:25:34 UTC 2017 

Review at  https://gerrit.osmocom.org/4257

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
---
M .gitignore
M examples/Makefile.am
A examples/udp-test-client.c
A examples/udp-test-server.c
A examples/udp-test.h
5 files changed, 227 insertions(+), 0 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/libosmo-netif refs/changes/57/4257/1

diff --git a/.gitignore b/.gitignore
index 2d582bd..4ee9929 100644
--- a/.gitignore
+++ b/.gitignore
@@ -51,3 +51,5 @@
 examples/stream-server
 
 Doxyfile
+/examples/udp-test-client
+/examples/udp-test-server
diff --git a/examples/Makefile.am b/examples/Makefile.am
index ddfaa48..df13808 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -14,8 +14,12 @@
 		  rs232-write			\
 		  rtp-udp-test-client		\
 		  rtp-udp-test-server		\
+		  udp-test-client		\
+		  udp-test-server		\
 		  osmux-test-input		\
 		  osmux-test-output
+
+noinst_HEADERS = udp-test.h
 
 ipa_stream_client_SOURCES = ipa-stream-client.c
 ipa_stream_client_LDADD = $(top_builddir)/src/libosmonetif.la \
@@ -57,6 +61,12 @@
 rtp_udp_test_server_LDADD = $(top_builddir)/src/libosmonetif.la \
 			    $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS)
 
+udp_test_client_SOURCES = udp-test-client.c
+udp_test_client_LDADD = $(top_builddir)/src/libosmonetif.la $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS)
+
+udp_test_server_SOURCES = udp-test-server.c
+udp_test_server_LDADD = $(top_builddir)/src/libosmonetif.la $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS)
+
 osmux_test_input_SOURCES = osmux-test-input.c
 osmux_test_input_LDADD = $(top_builddir)/src/libosmonetif.la \
 			 $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS)
diff --git a/examples/udp-test-client.c b/examples/udp-test-client.c
new file mode 100644
index 0000000..efd746b
--- /dev/null
+++ b/examples/udp-test-client.c
@@ -0,0 +1,43 @@
+#include "udp-test.h"
+
+static int read_cb(struct osmo_dgram *conn)
+{
+	struct msgb *msg = print_recv(conn);
+	if (!msg)
+		return -1;
+
+	if (msgb_length(msg))
+		if (msgb_data(msg)[0] >= NUM_MSG - 1)
+			please_dont_die = false; /* end test: */
+
+	msgb_free(msg);
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	uint8_t i;
+
+	if (!dgram_init(THOST, CPORT, SPORT, read_cb))
+		exit(EXIT_FAILURE);
+
+	for(i = 0; i < NUM_MSG + 1; i++) {
+		/* N. B: moving this alocation outside of the loop will result in segfault */
+		struct msgb *msg = msgb_alloc(MAX_MSG, "UDP/client");
+		if (!msg) {
+			LOGP(DUDP_TEST, LOGL_ERROR, "cann't allocate message\n");
+			return EXIT_FAILURE;
+		}
+
+		if (!mtrim(msg, i, i))
+			return EXIT_FAILURE;
+
+		LOGP(DUDP_TEST, LOGL_NOTICE, "queue [%u] %s\n", msgb_length(msg), msgb_hexdump(msg));
+		osmo_dgram_send(conn, msg);
+	}
+
+	main_loop(THOST, CPORT, SPORT);
+
+	return 0;
+}
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;
+}
diff --git a/examples/udp-test.h b/examples/udp-test.h
new file mode 100644
index 0000000..14bbd91
--- /dev/null
+++ b/examples/udp-test.h
@@ -0,0 +1,137 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <time.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/application.h>
+#include <osmocom/core/select.h>
+#include <osmocom/netif/datagram.h>
+
+#define MAX_MSG 255
+#define NUM_MSG 11
+#define DUDP_TEST 0
+#define THOST "127.0.0.1"
+#define SPORT 15000
+#define CPORT 15001
+
+static struct osmo_dgram *conn;
+static void *tall_test;
+bool please_dont_die = true;
+
+static void sighandler(int foo)
+{
+	LOGP(DLINP, LOGL_NOTICE, "closing UDP test...\n");
+	osmo_dgram_close(conn);
+	osmo_dgram_destroy(conn);
+	please_dont_die = false;
+}
+
+static inline struct msgb *print_recv(struct osmo_dgram *conn)
+{
+	struct msgb *msg = msgb_alloc(MAX_MSG, "UDP/test");
+	int bytes;
+
+	LOGP(DUDP_TEST, LOGL_NOTICE, "received datagram: ");
+
+	if (!msg) {
+		LOGPC(DUDP_TEST, LOGL_ERROR, "can't allocate message\n");
+		return NULL;
+	}
+
+	/* receive message: */
+	bytes = osmo_dgram_recv(conn, msg);
+	if (bytes < 0) {
+		LOGPC(DUDP_TEST, LOGL_ERROR, "can't receive message: %u\n", -bytes);
+		msgb_free(msg);
+		return NULL;
+	}
+
+	/* process message: */
+	LOGPC(DUDP_TEST, LOGL_NOTICE, "[%u] %s\n", bytes, msgb_hexdump(msg));
+
+	return msg;
+}
+
+static inline bool dgram_init(const char *host, uint16_t lport, uint16_t rport, void *read_cb)
+{
+	const struct log_info_cat udp_test_cat[] = {
+		[DUDP_TEST] = {
+			.name = "DUDP_TEST",
+			.description = "UDP test",
+			.color = "\033[1;35m",
+			.enabled = 1, .loglevel = LOGL_NOTICE,
+		},
+	};
+
+	const struct log_info udp_test_log_info = {
+		.filter_fn = NULL,
+		.cat = udp_test_cat,
+		.num_cat = ARRAY_SIZE(udp_test_cat),
+	};
+
+	signal(SIGINT, sighandler);
+
+	tall_test = talloc_named_const(NULL, 1, "udp_test");
+
+	osmo_init_logging(&udp_test_log_info);
+	log_set_log_level(osmo_stderr_target, LOGL_NOTICE);
+
+	conn = osmo_dgram_create(tall_test);
+	if (!conn) {
+		LOGP(DUDP_TEST, LOGL_ERROR, "cannot create UDP socket\n");
+		return false;
+	}
+
+	osmo_dgram_set_local_addr(conn, host);
+	osmo_dgram_set_local_port(conn, lport);
+	osmo_dgram_set_remote_addr(conn, host);
+	osmo_dgram_set_remote_port(conn, rport);
+	osmo_dgram_set_read_cb(conn, read_cb);
+
+	if (osmo_dgram_open(conn) < 0) {
+		LOGP(DUDP_TEST, LOGL_ERROR, "cannot open client connection %s:%u -> %s:%u\n", host, lport, host, rport);
+		return false;
+	}
+
+	return true;
+}
+
+static inline void main_loop(const char *host, uint16_t lport, uint16_t rport)
+{
+	LOGP(DUDP_TEST, LOGL_NOTICE, "Entering main loop: %s:%u -> %s:%u\n", host, lport, host, rport);
+
+	while(please_dont_die)
+		osmo_select_main(0);
+}
+
+/* Smart message trimmer:
+ * for all positive i trims msg to i - 1
+ * for i = 0 trims msg to 0
+ * for all positive x adds x to msg
+*/
+/*! Smart message trimmer.
+ *  \param[in] msg message buffer
+ *  \param[in] i trim value: for all positive i, msg is trimmed to i - 1, otherwise msg is trimmed to 0
+ *  \param[in] x message content: for all positive x, x is added to msg, otherwise it's ignored
+ */
+static inline bool mtrim(struct msgb *msg, uint8_t i, uint8_t x)
+{
+	if (msgb_trim(msg, i ? i - 1 : i) != 0) {
+		LOGP(DLINP, LOGL_ERROR, "failed to trim message by %u\n", i);
+		return false;
+	}
+
+	if (x)
+		msgb_put_u8(msg, x);
+
+	return true;
+}

-- 
To view, visit https://gerrit.osmocom.org/4257
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I08c0adf1cf9b6a6f1f7090b237d0497c2ec13cdf
Gerrit-PatchSet: 1
Gerrit-Project: libosmo-netif
Gerrit-Branch: master
Gerrit-Owner: Max <msuraev at sysmocom.de>

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