tests/echo-server.c

   1 /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil -*-
   2  *
   3  * echo-server.c --- Simple echo server for testing purposes.
   4  *
   5  * Copyright (C) 2007, Luis Oliveira  <loliveira@common-lisp.net>
   6  *
   7  * Permission is hereby granted, free of charge, to any person
   8  * obtaining a copy of this software and associated documentation
   9  * files (the "Software"), to deal in the Software without
  10  * restriction, including without limitation the rights to use, copy,
  11  * modify, merge, publish, distribute, sublicense, and/or sell copies
  12  * of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be
  16  * included in all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  19  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  21  * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  22  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  23  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  25  * DEALINGS IN THE SOFTWARE.
  26  */
  27
  28 /* TODO: IPv6 support, port to Winsock */
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <time.h>
  33 #include <ctype.h>
  34 #include <string.h>
  35
  36 #ifdef _WIN32
  37 #include <windows.h>
  38 #include <Winsock2.h>
  39 #include <Ws2tcpip.h>
  40 #else
  41 #include <unistd.h>
  42 #include <errno.h>
  43 #include <sys/types.h>
  44 #include <sys/socket.h>
  45 #include <netinet/in.h>
  46 #include <arpa/inet.h>
  47 #include <sys/select.h>
  48 #endif
  49
  50 #define DEFAULT_PORT 7
  51 #define BACKLOG 10
  52 #define MAXCONS FD_SETSIZE
  53
  54 static int
  55 sendallto(int s, char *buf, int len, struct sockaddr *to, socklen_t tolen)
  56 {
  57     int sent = 0;
  58     int left = len;
  59
  60     while (sent < len) {
  61         int n = sendto(s, buf+sent, left, 0, to, tolen);
  62         if (n == -1) { return -1; }
  63         sent += n;
  64         left -= n;
  65     }
  66
  67     return 0;
  68 }
  69
  70 static char time_str[9];
  71
  72 static const char* timestamp()
  73 {
  74     time_t now = time(NULL);
  75     struct tm *tms = localtime(&now);
  76     strftime(time_str, (sizeof time_str)-1, "%T", tms);
  77     return time_str;
  78 }
  79
  80 int main(int argc, char *argv[])
  81 {
  82     int fds[MAXCONS];
  83     struct sockaddr_in addrs[MAXCONS];
  84     int conns = 0;
  85     int local_port, listenfd, dgramfd;
  86     struct sockaddr_in local;
  87     socklen_t sin_size = sizeof(struct sockaddr_in);
  88
  89     switch (argc) {
  90     case 1: local_port = DEFAULT_PORT; break;
  91     case 2: local_port = strtol(argv[1], NULL, 10); break;
  92     default:
  93         fprintf(stderr, "Usage: %s [port number]\n", argv[0]);
  94         fprintf(stderr, "The default port is: %d.\n", DEFAULT_PORT);
  95         exit(1);
  96     }
  97
  98     if (local_port <= 0 || local_port > 65535) {
  99         fprintf(stderr, "Error: invalid port number.\n");
 100         exit(1);
 101     }
 102
 103     printf("[%s] listening on port %d\n", timestamp(), local_port);
 104
 105     if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
 106         perror("socket");
 107         exit(1);
 108     }
 109
 110     fds[conns++] = listenfd;
 111
 112     if ((dgramfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
 113         perror("dgram socket");
 114         exit(1);
 115     }
 116
 117     fds[conns++] = dgramfd;
 118
 119     local.sin_family = AF_INET;
 120     local.sin_port = htons(local_port);
 121     local.sin_addr.s_addr = INADDR_ANY;
 122     memset(local.sin_zero, 0, sizeof local.sin_zero);
 123
 124     if (bind(listenfd, (struct sockaddr *) &local, sin_size) == -1) {
 125         perror("bind");
 126         exit(1);
 127     }
 128
 129     if (bind(dgramfd, (struct sockaddr *) &local, sin_size) == -1) {
 130         perror("dgram bind");
 131         exit(1);
 132     }
 133
 134     if (listen(listenfd, BACKLOG) == -1) {
 135         perror("listen");
 136         exit(1);
 137     }
 138
 139     for (;;) {
 140         int fd, max_fd, i, j, n;
 141         fd_set readfds;
 142         char buf[4096];
 143
 144         FD_ZERO(&readfds);
 145         for (i = 0, max_fd = -1; i < conns; i++) {
 146             if (fds[i] > max_fd)
 147                 max_fd = fds[i];
 148             FD_SET(fds[i], &readfds);
 149         }
 150
 151         if (select(max_fd+1, &readfds, NULL, NULL, NULL) == -1) {
 152             perror("select");
 153             exit(1);
 154         }
 155
 156         if (FD_ISSET(listenfd, &readfds)) {
 157             fd = accept(listenfd, (struct sockaddr *) &addrs[conns], &sin_size);
 158
 159             if (fd == -1) {
 160                 perror("accept");
 161                 continue;
 162             } else {
 163                 printf("[%s] accepted connection from %s (fd: %d)\n",
 164                        timestamp(), inet_ntoa(addrs[conns].sin_addr), fd);
 165                 fds[conns++] = fd;
 166             }
 167         }
 168
 169         for (i = 1; i < conns; i++) {
 170             if (FD_ISSET(fds[i], &readfds)) {
 171                 sin_size = sizeof(struct sockaddr_in);
 172                 n = recvfrom(fds[i], buf, (sizeof buf)-1, 0,
 173                              (struct sockaddr *) &addrs[i], &sin_size);
 174                 if (n == -1) {
 175                     perror("recvfrom");
 176                     goto error;
 177                 }
 178
 179                 // n == 0? huh hmm..
 180                 if (n == 0) goto error;
 181
 182                 printf("[%s] got %d bytes from %s (%s) ", timestamp(),
 183                        n, inet_ntoa(addrs[i].sin_addr),
 184                        i == 1 ? "udp" : "tcp");
 185
 186                 for (j = 0; j < n; j++) {
 187                     if (j % 75 == 0)
 188                         printf("\n  ");
 189
 190                     if (isprint(buf[j]))
 191                         putchar(buf[j]);
 192                     else
 193                         printf("[0x%x]", buf[j]);
 194
 195                     //putchar(isprint(buf[j]) ? buf[j] : '?');
 196                 }
 197
 198                 if (sendallto(fds[i], buf, n, (struct sockaddr *) &addrs[i],
 199                               sizeof(struct sockaddr_in)) == -1) {
 200                     perror("\nsendto");
 201                     goto error;
 202                 }
 203
 204                 printf("\n  (echoed)\n");
 205                 continue;
 206
 207             error:
 208                 if (i == 1) continue;
 209                 printf("[%s] removing fd %d from set\n", timestamp(), fds[i]);
 210                 close(fds[i]);
 211                 for (j = i+1; j < conns; j++) {
 212                     fds[j-1] = fds[j];
 213                     addrs[j-1] = addrs[j];
 214                 }
 215                 conns--;
 216             }
 217         }
 218     }
 219
 220     return 0;
 221 }