examples: add POSIX socket example

examples/posix_sockets/Makefile

+# name of your application
+APPLICATION = posix_sockets
+
+# If no BOARD is found in the environment, use this default:
+BOARD ?= native
+
+# This has to be the absolute path to the RIOT base directory:
+RIOTBASE ?= $(CURDIR)/../..
+
+BOARD_INSUFFICIENT_MEMORY := airfy-beacon chronos msb-430 msb-430h nrf51dongle nrf6310 \
+                             nucleo-f334 pca10000 pca10005 stm32f0discovery telosb wsn430-v1_3b \
+                             wsn430-v1_4 yunjia-nrf51822 z1
+
+# Include packages that pull up and auto-init the link layer.
+# NOTE: 6LoWPAN will be included if IEEE802.15.4 devices are present
+USEMODULE += gnrc_netif_default
+USEMODULE += auto_init_gnrc_netif
+# Specify the mandatory networking modules for socket communication via UDP
+USEMODULE += gnrc_ipv6_default
+USEMODULE += gnrc_udp
+USEMODULE += gnrc_conn_udp
+USEMODULE += posix_sockets
+# Add also the shell, some shell commands
+USEMODULE += shell
+USEMODULE += shell_commands
+USEMODULE += ps
+
+# Comment this out to disable code in RIOT that does safety checking
+# which is not needed in a production environment but helps in the
+# development process:
+CFLAGS += -DDEVELHELP
+
+# Change this to 0 show compiler invocation lines by default:
+QUIET ?= 1
+
+include $(RIOTBASE)/Makefile.include

examples/posix_sockets/README.md

+examples/posix_sockets
+======================
+This application is a showcase for RIOT's POSIX socket support. To
+keep things simple this application has only one-hop support and
+no routing capabilities.
+
+Usage
+=====
+
+Build, flash and start the application:
+```
+export BOARD=your_board
+make
+make flash
+make term
+```
+
+The `term` make target starts a terminal emulator for your board. It
+connects to a default port so you can interact with the shell, usually
+that is `/dev/ttyUSB0`. If your port is named differently, the
+`PORT=/dev/yourport` (not to be confused with the UDP port) variable can
+be used to override this.
+
+
+Example output
+==============
+
+The shell commands come with online help. Call `help` to see which commands
+exist and what they do.
+
+
+udp send fe80::1 1337 uiaeue
+2015-09-22 14:55:30,686 - INFO # > udp send fe80::1 1337 uiaeue
+2015-09-22 14:55:30,690 - INFO # Success: send 6 byte to fe80::1:1337
+
+Running the `help` command on an iotlab-m3:
+```
+2015-09-22 14:54:54,442 - INFO # help
+2015-09-22 14:54:54,443 - INFO # Command              Description
+2015-09-22 14:54:54,444 - INFO # ---------------------------------------
+2015-09-22 14:54:54,446 - INFO # udp                  send data over UDP and listen on UDP ports
+2015-09-22 14:54:54,447 - INFO # reboot               Reboot the node
+2015-09-22 14:54:54,449 - INFO # ps                   Prints information about running threads.
+2015-09-22 14:54:54,451 - INFO # mersenne_init        initializes the PRNG
+2015-09-22 14:54:54,453 - INFO # mersenne_get         returns 32 bit of pseudo randomness
+2015-09-22 14:54:54,454 - INFO # ifconfig             Configure network interfaces
+2015-09-22 14:54:54,455 - INFO # txtsnd               send raw data
+2015-09-22 14:54:54,457 - INFO # ncache               manage neighbor cache by hand
+2015-09-22 14:54:54,459 - INFO # routers              IPv6 default router list
+```
+
+Running the `ps` command on an iotlab-m3:
+
+```
+2015-09-22 14:54:57,134 - INFO # > ps
+2015-09-22 14:54:57,139 - INFO # 	pid | name                 | state    Q | pri | stack ( used) | location
+2015-09-22 14:54:57,143 - INFO # 	  1 | idle                 | pending  Q |  15 |   256 (  136) | 0x200001cc
+2015-09-22 14:54:57,157 - INFO # 	  2 | main                 | pending  Q |   7 |  1536 (  620) | 0x200002cc
+2015-09-22 14:54:57,164 - INFO # 	  3 | 6lo                  | bl rx    _ |   3 |  1024 (  404) | 0x20003ef8
+2015-09-22 14:54:57,169 - INFO # 	  4 | ipv6                 | bl rx    _ |   4 |  1024 (  436) | 0x20001cc0
+2015-09-22 14:54:57,172 - INFO # 	  5 | udp                  | bl rx    _ |   5 |  1024 (  268) | 0x20004660
+2015-09-22 14:54:57,177 - INFO # 	  6 | at86rfxx             | bl rx    _ |   3 |  1024 (  320) | 0x20001888
+2015-09-22 14:54:57,183 - INFO # 	    | SUM                  |            |     |  5888 ( 2184)
+```
+
+Start a UDP server with `udp server start <udp_port>`:
+
+```
+2015-09-22 14:55:09,563 - INFO # > udp server start 1337
+2015-09-22 14:55:09,564 - INFO # Success: started UDP server on port 1337
+```
+
+Send a UDP package with `udp send <dst_addr> <dst_port> <data>`:
+
+```
+2015-09-22 14:55:30,686 - INFO # > udp send fe80::3432:4833:46d4:9e06 1337 test
+2015-09-22 14:55:30,690 - INFO # Success: send 4 byte to [fe80::3432:4833:46d4:9e06]:1337
+```
+
+You can get the IPv6 address of the destination by using the `ifconfig` command on the receiver:
+
+```
+2015-09-22 14:58:10,394 - INFO # ifconfig
+2015-09-22 14:58:10,397 - INFO # Iface  6   HWaddr: 9e:06  Channel: 26  NID: 0x23  TX-Power: 0dBm  State: IDLE CSMA Retries: 4
+2015-09-22 14:58:10,399 - INFO #            Long HWaddr: 36:32:48:33:46:d4:9e:06
+2015-09-22 14:58:10,400 - INFO #            AUTOACK  CSMA  MTU:1280  6LO  IPHC
+2015-09-22 14:58:10,402 - INFO #            Source address length: 8
+2015-09-22 14:58:10,404 - INFO #            Link type: wireless
+2015-09-22 14:58:10,407 - INFO #            inet6 addr: ff02::1/128  scope: local [multicast]
+2015-09-22 14:58:10,415 - INFO #            inet6 addr: fe80::3432:4833:46d4:9e06/64  scope: local
+2015-09-22 14:58:10,416 - INFO #
+```

examples/posix_sockets/main.c

+/*
+ * Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     examples
+ * @{
+ *
+ * @file
+ * @brief       Example application for demonstrating the RIOT's POSIX sockets
+ *
+ * @author      Martine Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+
+#include "shell.h"
+
+#define MAIN_MSG_QUEUE_SIZE (1)
+
+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)
+{
+    puts("RIOT socket example application");
+    /* start shell */
+    puts("All up, running the shell now");
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
+
+    /* should be never reached */
+    return 0;
+}

examples/posix_sockets/udp.c

+/*
+ * Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     examples
+ * @{
+ *
+ * @file
+ * @brief       Demonstrating the sending and receiving of UDP data over POSIX sockets.
+ *
+ * @author      Martine Lenders <mlenders@inf.fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "thread.h"
+
+#define SERVER_MSG_QUEUE_SIZE   (8)
+#define SERVER_BUFFER_SIZE      (64)
+
+static int server_socket = -1;
+static char server_buffer[SERVER_BUFFER_SIZE];
+static char server_stack[THREAD_STACKSIZE_DEFAULT];
+static msg_t server_msg_queue[SERVER_MSG_QUEUE_SIZE];
+
+static void *_server_thread(void *args)
+{
+    struct sockaddr_in6 server_addr;
+    uint16_t port;
+    msg_init_queue(server_msg_queue, SERVER_MSG_QUEUE_SIZE);
+    server_socket = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+    /* parse port */
+    port = (uint16_t)atoi((char *)args);
+    if (port == 0) {
+        puts("Error: invalid port specified");
+        return NULL;
+    }
+    server_addr.sin6_family = AF_INET6;
+    memset(&server_addr.sin6_addr, 0, sizeof(server_addr.sin6_addr));
+    server_addr.sin6_port = htons(port);
+    if (server_socket < 0) {
+        puts("error initializing socket");
+        server_socket = 0;
+        return NULL;
+    }
+    if (bind(server_socket, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
+        server_socket = -1;
+        puts("error binding socket");
+        return NULL;
+    }
+    printf("Success: started UDP server on port %" PRIu16 "\n", port);
+    while (1) {
+        int res;
+        struct sockaddr_in6 src;
+        socklen_t src_len = sizeof(struct sockaddr_in6);
+        if ((res = recvfrom(server_socket, server_buffer, sizeof(server_buffer), 0,
+                            (struct sockaddr *)&src, &src_len)) < 0) {
+            puts("Error on receive");
+        }
+        else if (res == 0) {
+            puts("Peer did shut down");
+        }
+        else {
+            printf("Received data: ");
+            puts(server_buffer);
+        }
+    }
+    return NULL;
+}
+
+static int udp_send(char *addr_str, char *port_str, char *data, unsigned int num,
+                    unsigned int delay)
+{
+    struct sockaddr_in6 src, dst;
+    size_t data_len = strlen(data);
+    uint16_t port;
+    int s;
+    src.sin6_family = AF_INET6;
+    dst.sin6_family = AF_INET6;
+    memset(&src.sin6_addr, 0, sizeof(src.sin6_addr));
+    /* parse destination address */
+    if (inet_pton(AF_INET6, addr_str, &dst.sin6_addr) != 1) {
+        puts("Error: unable to parse destination address");
+        return 1;
+    }
+    /* parse port */
+    port = (uint16_t)atoi(port_str);
+    dst.sin6_port = htons(port);
+    src.sin6_port = htons(port);
+    s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+    if (s < 0) {
+        puts("error initializing socket");
+        return 1;
+    }
+    for (unsigned int i = 0; i < num; i++) {
+        if (sendto(s, data, data_len, 0, (struct sockaddr *)&dst, sizeof(dst)) < 0) {
+            puts("could not send");
+        }
+        else {
+            printf("Success: send %u byte to %s:%u\n", (unsigned)data_len, addr_str, port);
+        }
+
+        usleep(delay);
+    }
+    close(s);
+    return 0;
+}
+
+static int udp_start_server(char *port_str)
+{
+    /* check if server is already running */
+    if (server_socket >= 0) {
+        puts("Error: server already running");
+        return 1;
+    }
+    /* start server (which means registering pktdump for the chosen port) */
+    if (thread_create(server_stack, sizeof(server_stack), THREAD_PRIORITY_MAIN - 1,
+                      CREATE_STACKTEST, _server_thread, port_str, "UDP server") <= KERNEL_PID_UNDEF) {
+        server_socket = -1;
+        puts("error initializing thread");
+        return 1;
+    }
+    return 0;
+}
+
+int udp_cmd(int argc, char **argv)
+{
+    if (argc < 2) {
+        printf("usage: %s [send|server]\n", argv[0]);
+        return 1;
+    }
+
+    if (strcmp(argv[1], "send") == 0) {
+        uint32_t num = 1;
+        uint32_t delay = 1000000;
+        if (argc < 5) {
+            printf("usage: %s send <addr> <port> <data> [<num> [<delay in us>]]\n",
+                   argv[0]);
+            return 1;
+        }
+        if (argc > 5) {
+            num = (uint32_t)atoi(argv[5]);
+        }
+        if (argc > 6) {
+            delay = (uint32_t)atoi(argv[6]);
+        }
+        return udp_send(argv[2], argv[3], argv[4], num, delay);
+    }
+    else if (strcmp(argv[1], "server") == 0) {
+        if (argc < 3) {
+            printf("usage: %s server [start|stop]\n", argv[0]);
+            return 1;
+        }
+        if (strcmp(argv[2], "start") == 0) {
+            if (argc < 4) {
+                printf("usage %s server start <port>\n", argv[0]);
+                return 1;
+            }
+            return udp_start_server(argv[3]);
+        }
+        else {
+            puts("error: invalid command");
+            return 1;
+        }
+    }
+    else {
+        puts("error: invalid command");
+        return 1;
+    }
+}
+
+/** @} */