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         return res;
 152 }
 153
 154
 155 /****************************************************************************
 156 open a socket of the specified type, port and address for incoming data
 157 ****************************************************************************/
 158 static int open_socket_in(int type, int port, struct in_addr *address)
 159 {
 160         struct hostent *hp;
 161         struct sockaddr_in sock;
 162         char host_name[MAXHOSTNAMELEN];
 163         int res;
 164         int one=1;
 165
 166         /* get my host name */
 167         if (gethostname(host_name, sizeof(host_name)) == -1) {
 168                 rprintf(FERROR,"gethostname failed\n");
 169                 return -1;
 170         }
 171
 172         /* get host info */
 173         if ((hp = gethostbyname(host_name)) == 0) {
 174                 rprintf(FERROR,"gethostbyname: Unknown host %s\n",host_name);
 175                 return -1;
 176         }
 177
 178         memset((char *)&sock,0,sizeof(sock));
 179         memcpy((char *)&sock.sin_addr,(char *)hp->h_addr, hp->h_length);
 180         sock.sin_port = htons(port);
 181         sock.sin_family = hp->h_addrtype;
 182         if (address) {
 183                 sock.sin_addr = *address;
 184         } else {
 185                 sock.sin_addr.s_addr = INADDR_ANY;
 186         }
 187         res = socket(hp->h_addrtype, type, 0);
 188         if (res == -1) {
 189                 rprintf(FERROR,"socket failed\n");
 190                 return -1;
 191         }
 192
 193         setsockopt(res,SOL_SOCKET,SO_REUSEADDR,(char *)&one,sizeof(one));
 194
 195         /* now we've got a socket - we need to bind it */
 196         if (bind(res, (struct sockaddr * ) &sock,sizeof(sock)) == -1) {
 197                 rprintf(FERROR,"bind failed on port %d\n", port);
 198                 close(res);
 199                 return -1;
 200         }
 201
 202         return res;
 203 }
 204
 205
 206 /****************************************************************************
 207 determine if a file descriptor is in fact a socket
 208 ****************************************************************************/
 209 int is_a_socket(int fd)
 210 {
 211         int v,l;
 212         l = sizeof(int);
 213         return(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0);
 214 }
 215
 216
 217 void start_accept_loop(int port, int (*fn)(int ))
 218 {
 219         int s;
 220         extern struct in_addr socket_address;
 221
 222         /* open an incoming socket */
 223         s = open_socket_in(SOCK_STREAM, port, &socket_address);
 224         if (s == -1)
 225                 exit_cleanup(RERR_SOCKETIO);
 226
 227         /* ready to listen */
 228         if (listen(s, 5) == -1) {
 229                 close(s);
 230                 exit_cleanup(RERR_SOCKETIO);
 231         }
 232
 233
 234         /* now accept incoming connections - forking a new process
 235            for each incoming connection */
 236         while (1) {
 237                 fd_set fds;
 238                 int fd;
 239                 struct sockaddr addr;
 240                 int in_addrlen = sizeof(addr);
 241
 242                 FD_ZERO(&fds);
 243                 FD_SET(s, &fds);
 244
 245                 if (select(s+1, &fds, NULL, NULL, NULL) != 1) {
 246                         continue;
 247                 }
 248
 249                 if(!FD_ISSET(s, &fds)) continue;
 250
 251                 fd = accept(s,&addr,&in_addrlen);
 252
 253                 if (fd == -1) continue;
 254
 255                 signal(SIGCHLD, SIG_IGN);
 256
 257                 /* we shouldn't have any children left hanging around
 258                    but I have had reports that on Digital Unix zombies
 259                    are produced, so this ensures that they are reaped */
 260 #ifdef WNOHANG
 261                 while (waitpid(-1, NULL, WNOHANG) > 0);
 262 #endif
 263
 264                 if (fork()==0) {
 265                         close(s);
 266
 267                         _exit(fn(fd));
 268                 }
 269
 270                 close(fd);
 271         }
 272 }
 273
 274
 275 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
 276
 277 struct
 278 {
 279   char *name;
 280   int level;
 281   int option;
 282   int value;
 283   int opttype;
 284 } socket_options[] = {
 285   {"SO_KEEPALIVE",      SOL_SOCKET,    SO_KEEPALIVE,    0,                 OPT_BOOL},
 286   {"SO_REUSEADDR",      SOL_SOCKET,    SO_REUSEADDR,    0,                 OPT_BOOL},
 287   {"SO_BROADCAST",      SOL_SOCKET,    SO_BROADCAST,    0,                 OPT_BOOL},
 288 #ifdef TCP_NODELAY
 289   {"TCP_NODELAY",       IPPROTO_TCP,   TCP_NODELAY,     0,                 OPT_BOOL},
 290 #endif
 291 #ifdef IPTOS_LOWDELAY
 292   {"IPTOS_LOWDELAY",    IPPROTO_IP,    IP_TOS,          IPTOS_LOWDELAY,    OPT_ON},
 293 #endif
 294 #ifdef IPTOS_THROUGHPUT
 295   {"IPTOS_THROUGHPUT",  IPPROTO_IP,    IP_TOS,          IPTOS_THROUGHPUT,  OPT_ON},
 296 #endif
 297 #ifdef SO_SNDBUF
 298   {"SO_SNDBUF",         SOL_SOCKET,    SO_SNDBUF,       0,                 OPT_INT},
 299 #endif
 300 #ifdef SO_RCVBUF
 301   {"SO_RCVBUF",         SOL_SOCKET,    SO_RCVBUF,       0,                 OPT_INT},
 302 #endif
 303 #ifdef SO_SNDLOWAT
 304   {"SO_SNDLOWAT",       SOL_SOCKET,    SO_SNDLOWAT,     0,                 OPT_INT},
 305 #endif
 306 #ifdef SO_RCVLOWAT
 307   {"SO_RCVLOWAT",       SOL_SOCKET,    SO_RCVLOWAT,     0,                 OPT_INT},
 308 #endif
 309 #ifdef SO_SNDTIMEO
 310   {"SO_SNDTIMEO",       SOL_SOCKET,    SO_SNDTIMEO,     0,                 OPT_INT},
 311 #endif
 312 #ifdef SO_RCVTIMEO
 313   {"SO_RCVTIMEO",       SOL_SOCKET,    SO_RCVTIMEO,     0,                 OPT_INT},
 314 #endif
 315   {NULL,0,0,0,0}};
 316
 317
 318
 319 /****************************************************************************
 320 set user socket options
 321 ****************************************************************************/
 322 void set_socket_options(int fd, char *options)
 323 {
 324         char *tok;
 325         if (!options || !*options) return;
 326
 327         options = strdup(options);
 328
 329         if (!options) out_of_memory("set_socket_options");
 330
 331         for (tok=strtok(options, " \t,"); tok; tok=strtok(NULL," \t,")) {
 332                 int ret=0,i;
 333                 int value = 1;
 334                 char *p;
 335                 int got_value = 0;
 336
 337                 if ((p = strchr(tok,'='))) {
 338                         *p = 0;
 339                         value = atoi(p+1);
 340                         got_value = 1;
 341                 }
 342
 343                 for (i=0;socket_options[i].name;i++)
 344                         if (strcmp(socket_options[i].name,tok)==0)
 345                                 break;
 346
 347                 if (!socket_options[i].name) {
 348                         rprintf(FERROR,"Unknown socket option %s\n",tok);
 349                         continue;
 350                 }
 351
 352                 switch (socket_options[i].opttype) {
 353                 case OPT_BOOL:
 354                 case OPT_INT:
 355                         ret = setsockopt(fd,socket_options[i].level,
 356                                          socket_options[i].option,(char *)&value,sizeof(int));
 357                         break;
 358
 359                 case OPT_ON:
 360                         if (got_value)
 361                                 rprintf(FERROR,"syntax error - %s does not take a value\n",tok);
 362
 363                         {
 364                                 int on = socket_options[i].value;
 365                                 ret = setsockopt(fd,socket_options[i].level,
 366                                                  socket_options[i].option,(char *)&on,sizeof(int));
 367                         }
 368                         break;
 369                 }
 370
 371                 if (ret != 0)
 372                         rprintf(FERROR,"Failed to set socket option %s\n",tok);
 373         }
 374
 375         free(options);
 376 }
 377
 378 /****************************************************************************
 379 become a daemon, discarding the controlling terminal
 380 ****************************************************************************/
 381 void become_daemon(void)
 382 {
 383         int i;
 384
 385         if (fork()) {
 386                 _exit(0);
 387         }
 388
 389         /* detach from the terminal */
 390 #ifdef HAVE_SETSID
 391         setsid();
 392 #else
 393 #ifdef TIOCNOTTY
 394         i = open("/dev/tty", O_RDWR);
 395         if (i >= 0) {
 396                 ioctl(i, (int) TIOCNOTTY, (char *)0);
 397                 close(i);
 398         }
 399 #endif /* TIOCNOTTY */
 400 #endif
 401         /* make sure that stdin, stdout an stderr don't stuff things
 402            up (library functions, for example) */
 403         for (i=0;i<3;i++) {
 404                 close(i);
 405                 open("/dev/null", O_RDWR);
 406         }
 407 }
 408
 409 /*******************************************************************
 410  return the IP addr of the client as a string
 411  ******************************************************************/
 412 char *client_addr(int fd)
 413 {
 414         struct sockaddr sa;
 415         struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
 416         int     length = sizeof(sa);
 417         static char addr_buf[100];
 418         static int initialised;
 419
 420         if (initialised) return addr_buf;
 421
 422         initialised = 1;
 423
 424         if (getpeername(fd, &sa, &length)) {
 425                 exit_cleanup(RERR_SOCKETIO);
 426         }
 427
 428         strlcpy(addr_buf,(char *)inet_ntoa(sockin->sin_addr), sizeof(addr_buf));
 429         return addr_buf;
 430 }
 431
 432
 433 /*******************************************************************
 434  return the DNS name of the client
 435  ******************************************************************/
 436 char *client_name(int fd)
 437 {
 438         struct sockaddr sa;
 439         struct sockaddr_in *sockin = (struct sockaddr_in *) (&sa);
 440         int     length = sizeof(sa);
 441         static char name_buf[100];
 442         struct hostent *hp;
 443         char **p;
 444         char *def = "UNKNOWN";
 445         static int initialised;
 446
 447         if (initialised) return name_buf;
 448
 449         initialised = 1;
 450
 451         strcpy(name_buf,def);
 452
 453         if (getpeername(fd, &sa, &length)) {
 454                 exit_cleanup(RERR_SOCKETIO);
 455         }
 456
 457         /* Look up the remote host name. */
 458         if ((hp = gethostbyaddr((char *) &sockin->sin_addr,
 459                                 sizeof(sockin->sin_addr),
 460                                 AF_INET))) {
 461                 strlcpy(name_buf,(char *)hp->h_name,sizeof(name_buf));
 462         }
 463
 464
 465         /* do a forward lookup as well to prevent spoofing */
 466         hp = gethostbyname(name_buf);
 467         if (!hp) {
 468                 strcpy(name_buf,def);
 469                 rprintf(FERROR,"reverse name lookup failed\n");
 470         } else {
 471                 for (p=hp->h_addr_list;*p;p++) {
 472                         if (memcmp(*p, &sockin->sin_addr, hp->h_length) == 0) {
 473                                 break;
 474                         }
 475                 }
 476                 if (!*p) {
 477                         strcpy(name_buf,def);
 478                         rprintf(FERROR,"reverse name lookup mismatch - spoofed address?\n");
 479                 }
 480         }
 481
 482         return name_buf;
 483 }
 484
 485 /*******************************************************************
 486 convert a string to an IP address. The string can be a name or
 487 dotted decimal number
 488   ******************************************************************/
 489 struct in_addr *ip_address(const char *str)
 490 {
 491         static struct in_addr ret;
 492         struct hostent *hp;
 493
 494         /* try as an IP address */
 495         if (inet_aton(str, &ret) != 0) {
 496                 return &ret;
 497         }
 498
 499         /* otherwise assume it's a network name of some sort and use
 500            gethostbyname */
 501         if ((hp = gethostbyname(str)) == 0) {
 502                 rprintf(FERROR, "gethostbyname: Unknown host. %s\n",str);
 503                 return NULL;
 504         }
 505
 506         if (hp->h_addr == NULL) {
 507                 rprintf(FERROR, "gethostbyname: host address is invalid for host %s\n",str);
 508                 return NULL;
 509         }
 510
 511         if (hp->h_length > sizeof(ret)) {
 512                 rprintf(FERROR, "gethostbyname: host address is too large\n");
 513                 return NULL;
 514         }
 515
 516         memcpy(&ret.s_addr, hp->h_addr, hp->h_length);
 517
 518         return(&ret);
 519 }