examples/gnrc_networking: move udp command to shell commands

The `udp` command is a valuable debugging tool that is also useful
outside of the gnrc_networking example.

To enable easy sending of udp messages in other applications during
development, move the `udp` command to the shell module and introduce
the `gnrc_udp_cmd` pseudo-module to enable it.

examples/gnrc_networking/Makefile

@@ -13,17 +13,14 @@ USEMODULE += gnrc_netdev_default
 USEMODULE += auto_init_gnrc_netif
 # Activate ICMPv6 error messages
 USEMODULE += gnrc_icmpv6_error
-# Specify the mandatory networking modules for IPv6 and UDP
+# Specify the mandatory networking module for a IPv6 routing node
 USEMODULE += gnrc_ipv6_router_default
-USEMODULE += gnrc_udp
 # Add a routing protocol
 USEMODULE += gnrc_rpl
 USEMODULE += auto_init_gnrc_rpl
-# This application dumps received packets to STDIO using the pktdump module
-USEMODULE += gnrc_pktdump
 # Additional networking modules that can be dropped if not needed
 USEMODULE += gnrc_icmpv6_echo
-USEMODULE += netutils
+USEMODULE += gnrc_udp_cmd
 # Add also the shell, some shell commands
 USEMODULE += shell
 USEMODULE += shell_commands

examples/gnrc_networking/main.c

@@ -26,13 +26,6 @@
 #define MAIN_QUEUE_SIZE     (8)
 static msg_t _main_msg_queue[MAIN_QUEUE_SIZE];
 
-extern int udp_cmd(int argc, char **argv);
-
-static const shell_command_t shell_commands[] = {
-    { "udp", "send data over UDP and listen on UDP ports", udp_cmd },
-    { NULL, NULL, NULL }
-};
-
 int main(void)
 {
     /* we need a message queue for the thread running the shell in order to
@@ -43,7 +36,7 @@ int main(void)
     /* start shell */
     puts("All up, running the shell now");
     char line_buf[SHELL_DEFAULT_BUFSIZE];
-    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     /* should be never reached */
     return 0;

makefiles/pseudomodules.inc.mk

@@ -66,6 +66,7 @@ PSEUDOMODULES += gnrc_sixlowpan_frag_sfr_stats
 PSEUDOMODULES += gnrc_sixlowpan_iphc_nhc
 PSEUDOMODULES += gnrc_sixlowpan_nd_border_router
 PSEUDOMODULES += gnrc_sixlowpan_router_default
+PSEUDOMODULES += gnrc_udp_cmd
 PSEUDOMODULES += gnrc_sock_async
 PSEUDOMODULES += gnrc_sock_check_reuse
 PSEUDOMODULES += gnrc_txtsnd

sys/Makefile.dep

@@ -260,6 +260,10 @@ ifneq (,$(filter shell_commands,$(USEMODULE)))
     USEMODULE += netutils
   endif
 
+  ifneq (,$(gnrc_udp_cmd,$(USEMODULE)))
+    USEMODULE += netutils
+  endif
+
   ifneq (,$(filter nimble_netif,$(USEMODULE)))
     USEMODULE += nimble_scanner
     USEMODULE += nimble_scanlist

sys/net/gnrc/Makefile.dep

@@ -366,6 +366,11 @@ ifneq (,$(filter gnrc_udp,$(USEMODULE)))
   USEMODULE += udp
 endif
 
+ifneq (,$(filter gnrc_udp_cmd,$(USEMODULE)))
+  USEMODULE += gnrc_udp
+  USEMODULE += gnrc_pktdump
+endif
+
 ifneq (,$(filter gnrc_tcp,$(USEMODULE)))
   DEFAULT_MODULE += auto_init_gnrc_tcp
   USEMODULE += gnrc_nettype_tcp

sys/shell/commands/Makefile

@@ -35,6 +35,9 @@ endif
 ifneq (,$(filter gnrc_netif,$(USEMODULE)))
   SRC += sc_gnrc_netif.c
 endif
+ifneq (,$(filter gnrc_udp_cmd,$(USEMODULE)))
+  SRC += sc_gnrc_udp.c
+endif
 ifneq (,$(filter netstats_neighbor,$(USEMODULE)))
   SRC += sc_netstats_nb.c
 endif

sys/shell/commands/sc_gnrc_udp.c

@@ -7,7 +7,7 @@
  */
 
 /**
- * @ingroup     examples
+ * @ingroup     sys_shell_commands
  * @{
  *
  * @file
@@ -41,7 +41,7 @@ static gnrc_netreg_entry_t server =
                         GNRC_NETREG_ENTRY_INIT_PID(GNRC_NETREG_DEMUX_CTX_ALL,
                                                    KERNEL_PID_UNDEF);
 
-static void send(char *addr_str, char *port_str, char *data, unsigned int num,
+static void send(char *addr_str, const char *port_str, const void *data, size_t num,
                  unsigned int delay)
 {
     netif_t *netif;
@@ -149,7 +149,7 @@ static void stop_server(void)
     puts("Success: stopped UDP server");
 }
 
-int udp_cmd(int argc, char **argv)
+int _gnrc_udp_cmd(int argc, char **argv)
 {
     if (argc < 2) {
         printf("usage: %s [send|server]\n", argv[0]);

sys/shell/commands/shell_commands.c

@@ -203,6 +203,10 @@ extern int _cryptoauth(int argc, char **argv);
 extern int _bootloader_handler(int argc, char **argv);
 #endif
 
+#ifdef MODULE_GNRC_UDP_CMD
+extern int _gnrc_udp_cmd(int argc, char **argv);
+#endif
+
 const shell_command_t _shell_command_list[] = {
     {"reboot", "Reboot the node", _reboot_handler},
     {"version", "Prints current RIOT_VERSION", _version_handler},
@@ -296,6 +300,9 @@ const shell_command_t _shell_command_list[] = {
 #ifdef MODULE_GNRC_SIXLOWPAN_FRAG_STATS
     {"6lo_frag", "6LoWPAN fragment statistics", _gnrc_6lo_frag_stats },
 #endif
+#ifdef MODULE_GNRC_UDP_CMD
+    { "udp", "send data over UDP and listen on UDP ports", _gnrc_udp_cmd },
+#endif
 #ifdef MODULE_SAUL_REG
     {"saul", "interact with sensors and actuators using SAUL", _saul },
 #endif