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 <[email protected]>

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