Differences

This shows you the differences between two versions of the page.

--- workshop:sockets [2010-09-30 23:23]
equinox
+++ workshop:sockets [2015-09-16 12:41]
@@ Line 1: / Line 1: @@
-====== Vortrag/Workshop Einführung in Unix Socket Programmierung ======
-  * by Christian Pointner
-===== Beispielcode =====
-Es folgen ein paar simple Beispielprogramme die die Verwendung von Sockets unter Unix zeigen. Alle Beispiele und ein kleines Makefile können auch direkt per unten stehendem Link heruntergeladen werden:
-{{workshops:socket-examples.tar.gz|socket-examples.tar.gz}}
-Es folgt noch der Code für einen sehr simplen Chat Server anhand dessen die Verwendung des Resolvers (DNS etc.) gezeigt wird.
-==== Beispiel: udpclient ====
-<file>
-/*
- *  udpclient
- *
- *  This is a very basic UDP client example to show the usage of
- *  sockets.
- *
- *  Copyright (C) 2010 Christian Pointner <equinox@realraum.at>
- *
- *  udpclient is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  any later version.
- *
- *  udpclient is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with udpclient. If not, see <http://www.gnu.org/licenses/>.
- */
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-int main(int argc, char** argv)
-{
-  if(argc <= 2) {
-    fprintf(stderr,"too few arguments\n");
-    exit(1);
-  }
-  printf("starting UDP Client\n");
-  int sock = socket(AF_INET, SOCK_DGRAM, 0);
-  if(sock < 0) {
-    perror("socket() call failed");
-    exit(-1);
-  }
-  struct sockaddr_in remote_addr;
-  int alen, len;
-  alen = sizeof(remote_addr);
-  remote_addr.sin_family = AF_INET;
-  remote_addr.sin_port = htons(atoi(argv[2]));
-  if (inet_aton(argv[1], &remote_addr.sin_addr)==0) {
-    perror("inet_aton() call failed");
-    exit(-1);
-  }
-  uint8_t buffer[1500];
-  for (;;) {
-    if((len = read(0, buffer, 1500))==-1) {
-      perror("read() call failed");
-      exit(-1);
-    }
-    if((len = sendto(sock, buffer, len, 0, (struct sockaddr *)&remote_addr, alen))==-1) {
-      perror("sendto() call failed");
-      exit(-1);
-    }
-  }
-  close(sock);
-  printf("exiting UDP Client\n");
-  return 0;
-}
-</file>
-==== Beispiel: udpserver ====
-<file>
-/*
- *  udpserver
- *
- *  This is a very basic UDP client example to show the usage of
- *  sockets.
- *
- *  Copyright (C) 2010 Christian Pointner <equinox@realraum.at>
- *
- *  udpserver is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  any later version.
- *
- *  udpserver is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with udpserver. If not, see <http://www.gnu.org/licenses/>.
- */
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-int main(int argc, char** argv)
-{
-  printf("starting UDP Server\n");
-  int sock = socket(AF_INET, SOCK_DGRAM, 0);
-  if(sock < 0) {
-    perror("socket() call failed");
-    exit(-1);
-  }
-  struct sockaddr_in local_addr;
-  memset((char *) &local_addr, 0, sizeof(local_addr));
-  local_addr.sin_family = AF_INET;
-  local_addr.sin_port = htons(1234);
-  local_addr.sin_addr.s_addr = htonl(INADDR_ANY);
-  if(bind(sock, (struct sockaddr *)&local_addr, sizeof(local_addr))==-1) {
-    perror("bind() call failed");
-    exit(-1);
-  }
-  struct sockaddr_in remote_addr;
-  int alen, len;
-  alen = sizeof(remote_addr);
-  uint8_t buffer[1500];
-  for (;;) {
-    if((len = recvfrom(sock, buffer, 1500, 0, (struct sockaddr *)&remote_addr, &alen))==-1) {
-      perror("recvfrom() call failed");
-      exit(-1);
-    }
-    printf("Received %d Bytes from %s:%d\n", len, inet_ntoa(remote_addr.sin_addr), ntohs(remote_addr.sin_port));
-  }
-  close(sock);
-  printf("exiting UDP Server\n");
-  return 0;
-}
-</file>
-==== Beispiel: tcpclient ====
-<file>
-/*
- *  tcpclient
- *
- *  This is a very basic TCP client example to show the usage of
- *  sockets.
- *
- *  Copyright (C) 2010 Christian Pointner <equinox@realraum.at>
- *
- *  tcpclient is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  any later version.
- *
- *  tcpclient is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with tcpclient. If not, see <http://www.gnu.org/licenses/>.
- */
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-int main(int argc, char** argv)
-{
-  if(argc <= 2) {
-    fprintf(stderr,"too few arguments\n");
-    exit(1);
-  }
-  printf("starting TCP Client\n");
-  int sock = socket(AF_INET, SOCK_STREAM, 0);
-  if(sock < 0) {
-    perror("socket() call failed");
-    exit(-1);
-  }
-  struct sockaddr_in remote_addr;
-  remote_addr.sin_family = AF_INET;
-  remote_addr.sin_port = htons(atoi(argv[2]));
-  if (inet_aton(argv[1], &remote_addr.sin_addr)==0) {
-    perror("inet_aton() call failed");
-    exit(-1);
-  }
-  if(connect(sock, (struct sockaddr *)&remote_addr, sizeof(remote_addr))==-1) {
-    perror("connect() call failed");
-    exit(-1);
-  }
-  int len;
-  uint8_t buffer[1500];
-  for (;;) {
-    if((len = read(0, buffer, 1500))==-1) {
-      perror("read() call failed");
-      exit(-1);
-    }
-    int offset = 0;
-    int wlen;
-    for(;;) {
-      wlen = send(sock, &buffer[offset], len - offset, 0);
-      if(wlen == -1) {
-        if(errno != EINTR) {
-          perror("write() call failed");
-          exit(-1);
-        }
-        wlen = 0;
-      }
-      offset += wlen;
-      if(offset+1 >= len)
-        break;
-    }
-  }
-  close(sock);
-  printf("exiting TCP Client\n");
-  return 0;
-}
-</file>
-==== Beispiel: tcpserver ====
-<file>
-/*
- *  tcpserver
- *
- *  This is a very basic TCP server example to show the usage of
- *  sockets.
- *
- *  Copyright (C) 2010 Christian Pointner <equinox@realraum.at>
- *
- *  tcpserver is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  any later version.
- *
- *  tcpserver is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with tcpserver. If not, see <http://www.gnu.org/licenses/>.
- */
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-#include <sys/select.h>
-int main(int argc, char** argv)
-{
-  printf("starting TCP Server\n");
-  int server = socket(AF_INET, SOCK_STREAM, 0);
-  if(server < 0) {
-    perror("socket() call failed");
-    exit(-1);
-  }
-  struct sockaddr_in local_addr;
-  memset((char *) &local_addr, 0, sizeof(local_addr));
-  local_addr.sin_family = AF_INET;
-  local_addr.sin_port = htons(1234);
-  local_addr.sin_addr.s_addr = htonl(INADDR_ANY);
-  if(bind(server, (struct sockaddr *)&local_addr, sizeof(local_addr))==-1) {
-    perror("bind() call failed");
-    exit(-1);
-  }
-  if(listen(server, 5)==-1) {
-    perror("listen() call failed");
-    exit(-1);
-  }
-  fd_set readfds, tmpfds;
-  FD_ZERO(&readfds);
-  FD_SET(server, &readfds);
-  int max_fd = server;
-  uint8_t buffer[1500];
-  struct sockaddr_in remote_addr;
-  memset (&remote_addr, 0, sizeof(remote_addr));
-  int len, alen=sizeof(remote_addr);
-  for (;;) {
-    memcpy(&tmpfds, &readfds, sizeof(tmpfds));
-    int num = select(max_fd+1, &tmpfds, NULL, NULL, NULL);
-    if(num == -1 && errno != EINTR) {
-      perror("select() call failed");
-      exit(-1);
-    }
-    if(num == -1 || !num)
-      continue;
-    if(FD_ISSET(server, &tmpfds)) {
-      int new_client = accept(server, (struct sockaddr *)&remote_addr, &alen);
-      if(new_client==-1) {
-        perror("accept() call failed");
-        exit(-1);
-      }
-      printf("new connection %s:%d (fd=%d)\n", inet_ntoa(remote_addr.sin_addr), ntohs(remote_addr.sin_port), new_client);
-      FD_SET(new_client, &readfds);
-      max_fd = (max_fd < new_client) ? new_client : max_fd;
-      FD_CLR(server, &tmpfds);
-    }
-    int fd;
-    for(fd=0; fd<=max_fd; ++fd) {
-      if(FD_ISSET(fd, &tmpfds)) {
-        len = recv(fd, buffer, 1500, 0);
-        if(len <= 0) {
-          if(len < 0) perror("recv() call failed");
-          else fprintf(stderr, "client closed connection\n");
-          printf("removing client (fd=%d)\n", fd);
-          FD_CLR(fd, &readfds);
-          close(fd);
-        }
-        else
-          printf("Received %d Bytes from client (fd=%d)\n", len, fd);
-      }
-    }
-  }
-  close(server);
-  printf("exiting TCP Server\n");
-  return 0;
-}
-</file>
-----
-{{tag>workshop}}

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