socket.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1998
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 /*
  20   socket functions used in rsync
  21
  22   */
  23
  24 #include "rsync.h"
  25
  26
  27 /* establish a proxy connection on an open socket to a web roxy by using the CONNECT
  28    method */
  29 static int establish_proxy_connection(int fd, char *host, int port)
  30 {
  31         char buffer[1024];
  32         char *cp;
  33
  34         slprintf(buffer, sizeof(buffer), "CONNECT %s:%d HTTP/1.0\r\n\r\n", host, port);
  35         if (write(fd, buffer, strlen(buffer)) != strlen(buffer)) {
  36                 rprintf(FERROR, "failed to write to proxy - %s\n",
  37                         strerror(errno));
  38                 return -1;
  39         }
  40
  41         for (cp = buffer; cp < &buffer[sizeof(buffer) - 1]; cp++) {
  42                 if (read(fd, cp, 1) != 1) {
  43                         rprintf(FERROR, "failed to read from proxy\n");
  44                         return -1;
  45                 }
  46                 if (*cp == '\n')
  47                         break;
  48         }
  49
  50         if (*cp != '\n')
  51                 cp++;
  52         *cp-- = '\0';
  53         if (*cp == '\r')
  54                 *cp = '\0';
  55         if (strncmp(buffer, "HTTP/", 5) != 0) {
  56                 rprintf(FERROR, "bad response from proxy - %s\n",
  57                         buffer);
  58                 return -1;
  59         }
  60         for (cp = &buffer[5]; isdigit(*cp) || (*cp == '.'); cp++)
  61                 ;
  62         while (*cp == ' ')
  63                 cp++;
  64         if (*cp != '2') {
  65                 rprintf(FERROR, "bad response from proxy - %s\n",
  66                         buffer);
  67                 return -1;
  68         }
  69         /* throw away the rest of the HTTP header */
  70         while (1) {
  71                 for (cp = buffer; cp < &buffer[sizeof(buffer) - 1];
  72                      cp++) {
  73                         if (read(fd, cp, 1) != 1) {
  74                                 rprintf(FERROR, "failed to read from proxy\n");
  75                                 return -1;
  76                         }
  77                         if (*cp == '\n')
  78                                 break;
  79                 }
  80                 if ((cp > buffer) && (*cp == '\n'))
  81                         cp--;
  82                 if ((cp == buffer) && ((*cp == '\n') || (*cp == '\r')))
  83                         break;
  84         }
  85         return 0;
  86 }
  87
  88
  89 /* open a socket to a tcp remote host with the specified port
  90    based on code from Warren
  91    proxy support by Stephen Rothwell */
  92 int open_socket_out(char *host, int port)
  93 {
  94         int type = SOCK_STREAM;
  95         struct sockaddr_in sock_out;
  96         int res;
  97         struct hostent *hp;
  98         char *h;
  99         unsigned p;
 100         int proxied = 0;
 101         char buffer[1024];
 102         char *cp;
 103
 104         /* if we have a RSYNC_PROXY env variable then redirect our connetcion via a web proxy
 105            at the given address. The format is hostname:port */
 106         h = getenv("RSYNC_PROXY");
 107         proxied = (h != NULL) && (*h != '\0');
 108
 109         if (proxied) {
 110                 strlcpy(buffer, h, sizeof(buffer));
 111                 cp = strchr(buffer, ':');
 112                 if (cp == NULL) {
 113                         rprintf(FERROR, "invalid proxy specification\n");
 114                         return -1;
 115                 }
 116                 *cp++ = '\0';
 117                 p = atoi(cp);
 118                 h = buffer;
 119         } else {
 120                 h = host;
 121                 p = port;
 122         }
 123
 124         res = socket(PF_INET, type, 0);
 125         if (res == -1) {
 126                 return -1;
 127         }
 128
 129         hp = gethostbyname(h);
 130         if (!hp) {
 131                 rprintf(FERROR,"unknown host: %s\n", h);
 132                 close(res);
 133                 return -1;
 134         }
 135
 136         memcpy(&sock_out.sin_addr, hp->h_addr, hp->h_length);
 137         sock_out.sin_port = htons(p);
 138         sock_out.sin_family = PF_INET;
 139
 140         if (connect(res,(struct sockaddr *)&sock_out,sizeof(sock_out))) {
 141                 rprintf(FERROR,"failed to connect to %s - %s\n", h, strerror(errno));
 142                 close(res);
 143                 return -1;
 144         }
 145
 146         if (proxied && establish_proxy_connection(res, host, port) != 0) {
 147                 close(res);
 148                 return -1;
 149         }
 150
 151         set_nonblocking(res);
 152
 153         return res;
 154 }
 155
 156
 157 /****************************************************************************
 158 open a socket of the specified type, port and address for incoming data
 159 ****************************************************************************/
 160 static int open_socket_in(int type, int port)
 161 {
 162         struct hostent *hp;
 163         struct sockaddr_in sock;
 164         char host_name[MAXHOSTNAMELEN];
 165         int res;
 166         int one=1;
 167
 168         /* get my host name */
 169         if (gethostname(host_name, sizeof(host_name)) == -1) {
 170                 rprintf(FERROR,"gethostname failed\n");
 171                 return -1;
 172         }
 173
 174         /* get host info */
 175         if ((hp = gethostbyname(host_name)) == 0) {
 176                 rprintf(FERROR,"gethostbyname: Unknown host %s\n",host_name);
 177                 return -1;
 178         }
 179
 180         memset((char *)&sock,0,sizeof(sock));
 181         memcpy((char *)&sock.sin_addr,(char *)hp->h_addr, hp->h_length);
 182         sock.sin_port = htons(port);
 183         sock.sin_family = hp->h_addrtype;
 184         sock.sin_addr.s_addr = INADDR_ANY;
 185         res = socket(hp->h_addrtype, type, 0);
 186         if (res == -1) {
 187                 rprintf(FERROR,"socket failed\n");
 188                 return -1;
 189         }
 190
 191         setsockopt(res,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one));
 192
 193         /* now we've got a socket - we need to bind it */
 194         if (bind(res, (struct sockaddr * ) &sock,sizeof(sock)) == -1) {
 195                 rprintf(FERROR,"bind failed on port %d\n", port);
 196                 close(res);
 197                 return -1;
 198         }
 199
 200         return res;
 201 }
 202
 203
 204 /****************************************************************************
 205 determine if a file descriptor is in fact a socket
 206 ****************************************************************************/
 207 int is_a_socket(int fd)
 208 {
 209         int v,l;
 210         l = sizeof(int);
 211         return(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0);
 212 }
 213
 214
 215 void start_accept_loop(int port, int (*fn)(int ))
 216 {
 217         int s;
 218
 219         /* open an incoming socket */
 220         s = open_socket_in(SOCK_STREAM, port);
 221         if (s == -1)
 222                 exit_cleanup(RERR_SOCKETIO);
 223
 224         /* ready to listen */
 225         if (listen(s, 5) == -1) {
 226                 close(s);
 227                 exit_cleanup(RERR_SOCKETIO);
 228         }
 229
 230
 231         /* now accept incoming connections - forking a new process
 232            for each incoming connection */
 233         while (1) {
 234                 fd_set fds;
 235                 int fd;
 236                 struct sockaddr addr;
 237                 int in_addrlen = sizeof(addr);
 238
 239                 FD_ZERO(&fds);
 240                 FD_SET(s, &fds);
 241
 242                 if (select(s+1, &fds, NULL, NULL, NULL) != 1) {
 243                         continue;
 244                 }
 245
 246                 if(!FD_ISSET(s, &fds)) continue;
 247
 248                 fd = accept(s,&addr,&in_addrlen);
 249
 250                 if (fd == -1) continue;
 251
 252                 signal(SIGCHLD, SIG_IGN);
 253
 254                 /* we shouldn't have any children left hanging around
 255                    but I have had reports that on Digital Unix zombies
 256                    are produced, so this ensures that they are reaped */
 257 #ifdef WNOHANG
 258                 waitpid(-1, NULL, WNOHANG);
 259 #endif
 260
 261                 if (fork()==0) {
 262                         close(s);
 263
 264                         set_nonblocking(fd);
 265
 266                         _exit(fn(fd));
 267                 }
 268
 269                 close(fd);
 270         }
 271 }
 272
 273
 274 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
 275
 276 struct
 277 {
 278   char *name;
 279   int level;
 280   int option;
 281   int value;
 282   int opttype;
 283 } socket_options[] = {
 284   {"SO_KEEPALIVE",      SOL_SOCKET,    SO_KEEPALIVE,    0,                 OPT_BOOL},
 285   {"SO_REUSEADDR",      SOL_SOCKET,    SO_REUSEADDR,    0,                 OPT_BOOL},
 286   {"SO_BROADCAST",      SOL_SOCKET,    SO_BROADCAST,    0,                 OPT_BOOL},
 287 #ifdef TCP_NODELAY
 288   {"TCP_NODELAY",       IPPROTO_TCP,   TCP_NODELAY,     0,                 OPT_BOOL},
 289 #endif
 290 #ifdef IPTOS_LOWDELAY
 291   {"IPTOS_LOWDELAY",    IPPROTO_IP,    IP_TOS,          IPTOS_LOWDELAY,    OPT_ON},
 292 #endif
 293 #ifdef IPTOS_THROUGHPUT
 294   {"IPTOS_THROUGHPUT",  IPPROTO_IP,    IP_TOS,          IPTOS_THROUGHPUT,  OPT_ON},
 295 #endif
 296 #ifdef SO_SNDBUF
 297   {"SO_SNDBUF",         SOL_SOCKET,    SO_SNDBUF,       0,                 OPT_INT},
 298 #endif
 299 #ifdef SO_RCVBUF
 300   {"SO_RCVBUF",         SOL_SOCKET,    SO_RCVBUF,       0,                 OPT_INT},
 301 #endif
 302 #ifdef SO_SNDLOWAT
 303   {"SO_SNDLOWAT",       SOL_SOCKET,    SO_SNDLOWAT,     0,                 OPT_INT},
 304 #endif
 305 #ifdef SO_RCVLOWAT
 306   {"SO_RCVLOWAT",       SOL_SOCKET,    SO_RCVLOWAT,     0,                 OPT_INT},
 307 #endif
 308 #ifdef SO_SNDTIMEO
 309   {"SO_SNDTIMEO",       SOL_SOCKET,    SO_SNDTIMEO,     0,                 OPT_INT},
 310 #endif
 311 #ifdef SO_RCVTIMEO
 312   {"SO_RCVTIMEO",       SOL_SOCKET,    SO_RCVTIMEO,     0,                 OPT_INT},
 313 #endif
 314   {NULL,0,0,0,0}};
 315
 316
 317
 318 /****************************************************************************
 319 set user socket options
 320 ****************************************************************************/
 321 void set_socket_options(int fd, char *options)
 322 {
 323         char *tok;
 324         if (!options || !*options) return;
 325
 326         options = strdup(options);
 327
 328         if (!options) out_of_memory("set_socket_options");
 329
 330         for (tok=strtok(options, " \t,"); tok; tok=strtok(NULL," \t,")) {
 331                 int ret=0,i;
 332                 int value = 1;
 333                 char *p;
 334                 int got_value = 0;
 335
 336                 if ((p = strchr(tok,'='))) {
 337                         *p = 0;
 338                         value = atoi(p+1);
 339                         got_value = 1;
 340                 }
 341
 342                 for (i=0;socket_options[i].name;i++)
 343                         if (strcmp(socket_options[i].name,tok)==0)
 344                                 break;
 345
 346                 if (!socket_options[i].name) {
 347                         rprintf(FERROR,"Unknown socket option %s\n",tok);
 348                         continue;
 349                 }
 350
 351                 switch (socket_options[i].opttype) {
 352                 case OPT_BOOL:
 353                 case OPT_INT:
 354                         ret = setsockopt(fd,socket_options[i].level,
 355                                          socket_options[i].option,(char *)&value,sizeof(int));
 356                         break;
 357
 358                 case OPT_ON:
 359                         if (got_value)
 360                                 rprintf(FERROR,"syntax error - %s does not take a value\n",tok);
 361
 362                         {
 363                                 int on = socket_options[i].value;
 364                                 ret = setsockopt(fd,socket_options[i].level,
 365                                                  socket_options[i].option,(char *)&on,sizeof(int));
 366                         }
 367                         break;
 368                 }
 369
 370                 if (ret != 0)
 371                         rprintf(FERROR,"Failed to set socket option %s\n",tok);
 372         }
 373
 374         free(options);
 375 }
 376
 377 /****************************************************************************
 378 become a daemon, discarding the controlling terminal
 379 ****************************************************************************/
 380 void become_daemon(void)
 381 {
 382         int i;
 383
 384         if (fork()) {
 385                 _exit(0);
 386         }
 387
 388         /* detach from the terminal */
 389 #ifdef HAVE_SETSID
 390         setsid();
 391 #else
 392 #ifdef TIOCNOTTY
 393         i = open("/dev/tty", O_RDWR);
 394         if (i >= 0) {
 395                 ioctl(i, (int) TIOCNOTTY, (char *)0);
 396                 close(i);
 397         }
 398 #endif /* TIOCNOTTY */
 399 #endif
 400         /* make sure that stdin, stdout an stderr don't stuff things
 401            up (library functions, for example) */
 402         for (i=0;i<3;i++) {
 403                 close(i);
 404                 open("/dev/null", O_RDWR);
 405         }
 406 }
 407
 408 /*******************************************************************
 409  return the IP addr of the client as a string
 410  ******************************************************************/
 411 char *client_addr(int fd)
 412 {
 413         struct sockaddr sa;
 414         struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
 415         int     length = sizeof(sa);
 416         static char addr_buf[100];
 417         static int initialised;
 418
 419         if (initialised) return addr_buf;
 420
 421         initialised = 1;
 422
 423         if (getpeername(fd, &sa, &length)) {
 424                 exit_cleanup(RERR_SOCKETIO);
 425         }
 426
 427         strlcpy(addr_buf,(char *)inet_ntoa(sockin->sin_addr), sizeof(addr_buf));
 428         return addr_buf;
 429 }
 430
 431
 432 /*******************************************************************
 433  return the DNS name of the client
 434  ******************************************************************/
 435 char *client_name(int fd)
 436 {
 437         struct sockaddr sa;
 438         struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
 439         int     length = sizeof(sa);
 440         static char name_buf[100];
 441         struct hostent *hp;
 442         char **p;
 443         char *def = "UNKNOWN";
 444         static int initialised;
 445
 446         if (initialised) return name_buf;
 447
 448         initialised = 1;
 449
 450         strcpy(name_buf,def);
 451
 452         if (getpeername(fd, &sa, &length)) {
 453                 exit_cleanup(RERR_SOCKETIO);
 454         }
 455
 456         /* Look up the remote host name. */
 457         if ((hp = gethostbyaddr((char *) &sockin->sin_addr,
 458                                 sizeof(sockin->sin_addr),
 459                                 AF_INET))) {
 460                 strlcpy(name_buf,(char *)hp->h_name,sizeof(name_buf));
 461         }
 462
 463
 464         /* do a forward lookup as well to prevent spoofing */
 465         hp = gethostbyname(name_buf);
 466         if (!hp) {
 467                 strcpy(name_buf,def);
 468                 rprintf(FERROR,"reverse name lookup failed\n");
 469         } else {
 470                 for (p=hp->h_addr_list;*p;p++) {
 471                         if (memcmp(*p, &sockin->sin_addr, hp->h_length) == 0) {
 472                                 break;
 473                         }
 474                 }
 475                 if (!*p) {
 476                         strcpy(name_buf,def);
 477                         rprintf(FERROR,"reverse name lookup mismatch - spoofed address?\n");
 478                 }
 479         }
 480
 481         return name_buf;
 482 }