openssh/serverloop.c

   1 /* $OpenBSD: serverloop.c,v 1.145 2006/10/11 12:38:03 markus Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Server main loop for handling the interactive session.
   7  *
   8  * As far as I am concerned, the code I have written for this software
   9  * can be used freely for any purpose.  Any derived versions of this
  10  * software must be clearly marked as such, and if the derived work is
  11  * incompatible with the protocol description in the RFC file, it must be
  12  * called by a name other than "ssh" or "Secure Shell".
  13  *
  14  * SSH2 support by Markus Friedl.
  15  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include "includes.h"
  39
  40 #include <sys/types.h>
  41 #include <sys/param.h>
  42 #include <sys/wait.h>
  43 #include <sys/socket.h>
  44 #ifdef HAVE_SYS_TIME_H
  45 # include <sys/time.h>
  46 #endif
  47
  48 #include <netinet/in.h>
  49
  50 #include <errno.h>
  51 #include <fcntl.h>
  52 #include <pwd.h>
  53 #include <signal.h>
  54 #include <string.h>
  55 #include <termios.h>
  56 #include <unistd.h>
  57 #include <stdarg.h>
  58
  59 #include "xmalloc.h"
  60 #include "packet.h"
  61 #include "buffer.h"
  62 #include "log.h"
  63 #include "servconf.h"
  64 #include "canohost.h"
  65 #include "sshpty.h"
  66 #include "channels.h"
  67 #include "compat.h"
  68 #include "ssh1.h"
  69 #include "ssh2.h"
  70 #include "key.h"
  71 #include "cipher.h"
  72 #include "kex.h"
  73 #include "hostfile.h"
  74 #include "auth.h"
  75 #include "session.h"
  76 #include "dispatch.h"
  77 #include "auth-options.h"
  78 #include "serverloop.h"
  79 #include "misc.h"
  80
  81 extern ServerOptions options;
  82
  83 /* XXX */
  84 extern Kex *xxx_kex;
  85 extern Authctxt *the_authctxt;
  86 extern int use_privsep;
  87
  88 static Buffer stdin_buffer;     /* Buffer for stdin data. */
  89 static Buffer stdout_buffer;    /* Buffer for stdout data. */
  90 static Buffer stderr_buffer;    /* Buffer for stderr data. */
  91 static int fdin;                /* Descriptor for stdin (for writing) */
  92 static int fdout;               /* Descriptor for stdout (for reading);
  93                                    May be same number as fdin. */
  94 static int fderr;               /* Descriptor for stderr.  May be -1. */
  95 static u_long stdin_bytes = 0;  /* Number of bytes written to stdin. */
  96 static u_long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
  97 static u_long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
  98 static u_long fdout_bytes = 0;  /* Number of stdout bytes read from program. */
  99 static int stdin_eof = 0;       /* EOF message received from client. */
 100 static int fdout_eof = 0;       /* EOF encountered reading from fdout. */
 101 static int fderr_eof = 0;       /* EOF encountered readung from fderr. */
 102 static int fdin_is_tty = 0;     /* fdin points to a tty. */
 103 static int connection_in;       /* Connection to client (input). */
 104 static int connection_out;      /* Connection to client (output). */
 105 static int connection_closed = 0;       /* Connection to client closed. */
 106 static u_int buffer_high;       /* "Soft" max buffer size. */
 107 static int client_alive_timeouts = 0;
 108
 109 /*
 110  * This SIGCHLD kludge is used to detect when the child exits.  The server
 111  * will exit after that, as soon as forwarded connections have terminated.
 112  */
 113
 114 static volatile sig_atomic_t child_terminated = 0;      /* The child has terminated. */
 115
 116 /* Cleanup on signals (!use_privsep case only) */
 117 static volatile sig_atomic_t received_sigterm = 0;
 118
 119 /* prototypes */
 120 static void server_init_dispatch(void);
 121
 122 /*
 123  * Returns current time in seconds from Jan 1, 1970 with the maximum
 124  * available resolution.
 125  */
 126
 127 static double
 128 get_current_time(void)
 129 {
 130         struct timeval tv;
 131         gettimeofday(&tv, NULL);
 132         return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
 133 }
 134
 135
 136 /*
 137  * we write to this pipe if a SIGCHLD is caught in order to avoid
 138  * the race between select() and child_terminated
 139  */
 140 static int notify_pipe[2];
 141 static void
 142 notify_setup(void)
 143 {
 144         if (pipe(notify_pipe) < 0) {
 145                 error("pipe(notify_pipe) failed %s", strerror(errno));
 146         } else if ((fcntl(notify_pipe[0], F_SETFD, 1) == -1) ||
 147             (fcntl(notify_pipe[1], F_SETFD, 1) == -1)) {
 148                 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
 149                 close(notify_pipe[0]);
 150                 close(notify_pipe[1]);
 151         } else {
 152                 set_nonblock(notify_pipe[0]);
 153                 set_nonblock(notify_pipe[1]);
 154                 return;
 155         }
 156         notify_pipe[0] = -1;    /* read end */
 157         notify_pipe[1] = -1;    /* write end */
 158 }
 159 static void
 160 notify_parent(void)
 161 {
 162         if (notify_pipe[1] != -1)
 163                 write(notify_pipe[1], "", 1);
 164 }
 165 static void
 166 notify_prepare(fd_set *readset)
 167 {
 168         if (notify_pipe[0] != -1)
 169                 FD_SET(notify_pipe[0], readset);
 170 }
 171 static void
 172 notify_done(fd_set *readset)
 173 {
 174         char c;
 175
 176         if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
 177                 while (read(notify_pipe[0], &c, 1) != -1)
 178                         debug2("notify_done: reading");
 179 }
 180
 181 /*ARGSUSED*/
 182 static void
 183 sigchld_handler(int sig)
 184 {
 185         int save_errno = errno;
 186         child_terminated = 1;
 187 #ifndef _UNICOS
 188         mysignal(SIGCHLD, sigchld_handler);
 189 #endif
 190         notify_parent();
 191         errno = save_errno;
 192 }
 193
 194 /*ARGSUSED*/
 195 static void
 196 sigterm_handler(int sig)
 197 {
 198         received_sigterm = sig;
 199 }
 200
 201 /*
 202  * Make packets from buffered stderr data, and buffer it for sending
 203  * to the client.
 204  */
 205 static void
 206 make_packets_from_stderr_data(void)
 207 {
 208         u_int len;
 209
 210         /* Send buffered stderr data to the client. */
 211         while (buffer_len(&stderr_buffer) > 0 &&
 212             packet_not_very_much_data_to_write()) {
 213                 len = buffer_len(&stderr_buffer);
 214                 if (packet_is_interactive()) {
 215                         if (len > 512)
 216                                 len = 512;
 217                 } else {
 218                         /* Keep the packets at reasonable size. */
 219                         if (len > packet_get_maxsize())
 220                                 len = packet_get_maxsize();
 221                 }
 222                 packet_start(SSH_SMSG_STDERR_DATA);
 223                 packet_put_string(buffer_ptr(&stderr_buffer), len);
 224                 packet_send();
 225                 buffer_consume(&stderr_buffer, len);
 226                 stderr_bytes += len;
 227         }
 228 }
 229
 230 /*
 231  * Make packets from buffered stdout data, and buffer it for sending to the
 232  * client.
 233  */
 234 static void
 235 make_packets_from_stdout_data(void)
 236 {
 237         u_int len;
 238
 239         /* Send buffered stdout data to the client. */
 240         while (buffer_len(&stdout_buffer) > 0 &&
 241             packet_not_very_much_data_to_write()) {
 242                 len = buffer_len(&stdout_buffer);
 243                 if (packet_is_interactive()) {
 244                         if (len > 512)
 245                                 len = 512;
 246                 } else {
 247                         /* Keep the packets at reasonable size. */
 248                         if (len > packet_get_maxsize())
 249                                 len = packet_get_maxsize();
 250                 }
 251                 packet_start(SSH_SMSG_STDOUT_DATA);
 252                 packet_put_string(buffer_ptr(&stdout_buffer), len);
 253                 packet_send();
 254                 buffer_consume(&stdout_buffer, len);
 255                 stdout_bytes += len;
 256         }
 257 }
 258
 259 static void
 260 client_alive_check(void)
 261 {
 262         int channel_id;
 263
 264         /* timeout, check to see how many we have had */
 265         if (++client_alive_timeouts > options.client_alive_count_max) {
 266                 logit("Timeout, client not responding.");
 267                 cleanup_exit(255);
 268         }
 269
 270         /*
 271          * send a bogus global/channel request with "wantreply",
 272          * we should get back a failure
 273          */
 274         if ((channel_id = channel_find_open()) == -1) {
 275                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
 276                 packet_put_cstring("keepalive@openssh.com");
 277                 packet_put_char(1);     /* boolean: want reply */
 278         } else {
 279                 channel_request_start(channel_id, "keepalive@openssh.com", 1);
 280         }
 281         packet_send();
 282 }
 283
 284 /*
 285  * Sleep in select() until we can do something.  This will initialize the
 286  * select masks.  Upon return, the masks will indicate which descriptors
 287  * have data or can accept data.  Optionally, a maximum time can be specified
 288  * for the duration of the wait (0 = infinite).
 289  */
 290 static void
 291 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
 292     u_int *nallocp, u_int max_time_milliseconds)
 293 {
 294         struct timeval tv, *tvp;
 295         int ret;
 296         int client_alive_scheduled = 0;
 297         int program_alive_scheduled = 0;
 298
 299         /*
 300          * if using client_alive, set the max timeout accordingly,
 301          * and indicate that this particular timeout was for client
 302          * alive by setting the client_alive_scheduled flag.
 303          *
 304          * this could be randomized somewhat to make traffic
 305          * analysis more difficult, but we're not doing it yet.
 306          */
 307         if (compat20 &&
 308             max_time_milliseconds == 0 && options.client_alive_interval) {
 309                 client_alive_scheduled = 1;
 310                 max_time_milliseconds = options.client_alive_interval * 1000;
 311         }
 312
 313         /* Allocate and update select() masks for channel descriptors. */
 314         channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
 315
 316         if (compat20) {
 317 #if 0
 318                 /* wrong: bad condition XXX */
 319                 if (channel_not_very_much_buffered_data())
 320 #endif
 321                 FD_SET(connection_in, *readsetp);
 322         } else {
 323                 /*
 324                  * Read packets from the client unless we have too much
 325                  * buffered stdin or channel data.
 326                  */
 327                 if (buffer_len(&stdin_buffer) < buffer_high &&
 328                     channel_not_very_much_buffered_data())
 329                         FD_SET(connection_in, *readsetp);
 330                 /*
 331                  * If there is not too much data already buffered going to
 332                  * the client, try to get some more data from the program.
 333                  */
 334                 if (packet_not_very_much_data_to_write()) {
 335                         program_alive_scheduled = child_terminated;
 336                         if (!fdout_eof)
 337                                 FD_SET(fdout, *readsetp);
 338                         if (!fderr_eof)
 339                                 FD_SET(fderr, *readsetp);
 340                 }
 341                 /*
 342                  * If we have buffered data, try to write some of that data
 343                  * to the program.
 344                  */
 345                 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
 346                         FD_SET(fdin, *writesetp);
 347         }
 348         notify_prepare(*readsetp);
 349
 350         /*
 351          * If we have buffered packet data going to the client, mark that
 352          * descriptor.
 353          */
 354         if (packet_have_data_to_write())
 355                 FD_SET(connection_out, *writesetp);
 356
 357         /*
 358          * If child has terminated and there is enough buffer space to read
 359          * from it, then read as much as is available and exit.
 360          */
 361         if (child_terminated && packet_not_very_much_data_to_write())
 362                 if (max_time_milliseconds == 0 || client_alive_scheduled)
 363                         max_time_milliseconds = 100;
 364
 365         if (max_time_milliseconds == 0)
 366                 tvp = NULL;
 367         else {
 368                 tv.tv_sec = max_time_milliseconds / 1000;
 369                 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
 370                 tvp = &tv;
 371         }
 372
 373         /* Wait for something to happen, or the timeout to expire. */
 374         ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 375
 376         if (ret == -1) {
 377                 memset(*readsetp, 0, *nallocp);
 378                 memset(*writesetp, 0, *nallocp);
 379                 if (errno != EINTR)
 380                         error("select: %.100s", strerror(errno));
 381         } else {
 382                 if (ret == 0 && client_alive_scheduled)
 383                         client_alive_check();
 384                 if (!compat20 && program_alive_scheduled && fdin_is_tty) {
 385                         if (!fdout_eof)
 386                                 FD_SET(fdout, *readsetp);
 387                         if (!fderr_eof)
 388                                 FD_SET(fderr, *readsetp);
 389                 }
 390         }
 391
 392         notify_done(*readsetp);
 393 }
 394
 395 /*
 396  * Processes input from the client and the program.  Input data is stored
 397  * in buffers and processed later.
 398  */
 399 static void
 400 process_input(fd_set *readset)
 401 {
 402         int len;
 403         char buf[16384];
 404
 405         /* Read and buffer any input data from the client. */
 406         if (FD_ISSET(connection_in, readset)) {
 407                 len = read(connection_in, buf, sizeof(buf));
 408                 if (len == 0) {
 409                         verbose("Connection closed by %.100s",
 410                             get_remote_ipaddr());
 411                         connection_closed = 1;
 412                         if (compat20)
 413                                 return;
 414                         cleanup_exit(255);
 415                 } else if (len < 0) {
 416                         if (errno != EINTR && errno != EAGAIN) {
 417                                 verbose("Read error from remote host "
 418                                     "%.100s: %.100s",
 419                                     get_remote_ipaddr(), strerror(errno));
 420                                 cleanup_exit(255);
 421                         }
 422                 } else {
 423                         /* Buffer any received data. */
 424                         packet_process_incoming(buf, len);
 425                         fdout_bytes += len;
 426                 }
 427         }
 428         if (compat20)
 429                 return;
 430
 431         /* Read and buffer any available stdout data from the program. */
 432         if (!fdout_eof && FD_ISSET(fdout, readset)) {
 433                 errno = 0;
 434                 len = read(fdout, buf, sizeof(buf));
 435                 if (len < 0 && (errno == EINTR ||
 436                     (errno == EAGAIN && !child_terminated))) {
 437                         /* do nothing */
 438 #ifndef PTY_ZEROREAD
 439                 } else if (len <= 0) {
 440 #else
 441                 } else if ((!isatty(fdout) && len <= 0) ||
 442                     (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
 443 #endif
 444                         fdout_eof = 1;
 445                 } else {
 446                         buffer_append(&stdout_buffer, buf, len);
 447                         fdout_bytes += len;
 448                         debug ("FD out now: %ld", fdout_bytes);
 449                 }
 450         }
 451         /* Read and buffer any available stderr data from the program. */
 452         if (!fderr_eof && FD_ISSET(fderr, readset)) {
 453                 errno = 0;
 454                 len = read(fderr, buf, sizeof(buf));
 455                 if (len < 0 && (errno == EINTR ||
 456                     (errno == EAGAIN && !child_terminated))) {
 457                         /* do nothing */
 458 #ifndef PTY_ZEROREAD
 459                 } else if (len <= 0) {
 460 #else
 461                 } else if ((!isatty(fderr) && len <= 0) ||
 462                     (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
 463 #endif
 464                         fderr_eof = 1;
 465                 } else {
 466                         buffer_append(&stderr_buffer, buf, len);
 467                 }
 468         }
 469 }
 470
 471 /*
 472  * Sends data from internal buffers to client program stdin.
 473  */
 474 static void
 475 process_output(fd_set *writeset)
 476 {
 477         struct termios tio;
 478         u_char *data;
 479         u_int dlen;
 480         int len;
 481
 482         /* Write buffered data to program stdin. */
 483         if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
 484                 data = buffer_ptr(&stdin_buffer);
 485                 dlen = buffer_len(&stdin_buffer);
 486                 len = write(fdin, data, dlen);
 487                 if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
 488                         /* do nothing */
 489                 } else if (len <= 0) {
 490                         if (fdin != fdout)
 491                                 close(fdin);
 492                         else
 493                                 shutdown(fdin, SHUT_WR); /* We will no longer send. */
 494                         fdin = -1;
 495                 } else {
 496                         /* Successful write. */
 497                         if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
 498                             tcgetattr(fdin, &tio) == 0 &&
 499                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
 500                                 /*
 501                                  * Simulate echo to reduce the impact of
 502                                  * traffic analysis
 503                                  */
 504                                 packet_send_ignore(len);
 505                                 packet_send();
 506                         }
 507                         /* Consume the data from the buffer. */
 508                         buffer_consume(&stdin_buffer, len);
 509                         /* Update the count of bytes written to the program. */
 510                         stdin_bytes += len;
 511                 }
 512         }
 513         /* Send any buffered packet data to the client. */
 514         if (FD_ISSET(connection_out, writeset))
 515                 stdin_bytes += packet_write_poll();
 516 }
 517
 518 /*
 519  * Wait until all buffered output has been sent to the client.
 520  * This is used when the program terminates.
 521  */
 522 static void
 523 drain_output(void)
 524 {
 525         /* Send any buffered stdout data to the client. */
 526         if (buffer_len(&stdout_buffer) > 0) {
 527                 packet_start(SSH_SMSG_STDOUT_DATA);
 528                 packet_put_string(buffer_ptr(&stdout_buffer),
 529                                   buffer_len(&stdout_buffer));
 530                 packet_send();
 531                 /* Update the count of sent bytes. */
 532                 stdout_bytes += buffer_len(&stdout_buffer);
 533         }
 534         /* Send any buffered stderr data to the client. */
 535         if (buffer_len(&stderr_buffer) > 0) {
 536                 packet_start(SSH_SMSG_STDERR_DATA);
 537                 packet_put_string(buffer_ptr(&stderr_buffer),
 538                                   buffer_len(&stderr_buffer));
 539                 packet_send();
 540                 /* Update the count of sent bytes. */
 541                 stderr_bytes += buffer_len(&stderr_buffer);
 542         }
 543         /* Wait until all buffered data has been written to the client. */
 544         packet_write_wait();
 545 }
 546
 547 static void
 548 process_buffered_input_packets(void)
 549 {
 550         dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
 551 }
 552
 553 /*
 554  * Performs the interactive session.  This handles data transmission between
 555  * the client and the program.  Note that the notion of stdin, stdout, and
 556  * stderr in this function is sort of reversed: this function writes to
 557  * stdin (of the child program), and reads from stdout and stderr (of the
 558  * child program).
 559  */
 560 void
 561 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
 562 {
 563         fd_set *readset = NULL, *writeset = NULL;
 564         int max_fd = 0;
 565         u_int nalloc = 0;
 566         int wait_status;        /* Status returned by wait(). */
 567         pid_t wait_pid;         /* pid returned by wait(). */
 568         int waiting_termination = 0;    /* Have displayed waiting close message. */
 569         u_int max_time_milliseconds;
 570         u_int previous_stdout_buffer_bytes;
 571         u_int stdout_buffer_bytes;
 572         int type;
 573
 574         debug("Entering interactive session.");
 575
 576         /* Initialize the SIGCHLD kludge. */
 577         child_terminated = 0;
 578         mysignal(SIGCHLD, sigchld_handler);
 579
 580         if (!use_privsep) {
 581                 signal(SIGTERM, sigterm_handler);
 582                 signal(SIGINT, sigterm_handler);
 583                 signal(SIGQUIT, sigterm_handler);
 584         }
 585
 586         /* Initialize our global variables. */
 587         fdin = fdin_arg;
 588         fdout = fdout_arg;
 589         fderr = fderr_arg;
 590
 591         /* nonblocking IO */
 592         set_nonblock(fdin);
 593         set_nonblock(fdout);
 594         /* we don't have stderr for interactive terminal sessions, see below */
 595         if (fderr != -1)
 596                 set_nonblock(fderr);
 597
 598         if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
 599                 fdin_is_tty = 1;
 600
 601         connection_in = packet_get_connection_in();
 602         connection_out = packet_get_connection_out();
 603
 604         notify_setup();
 605
 606         previous_stdout_buffer_bytes = 0;
 607
 608         /* Set approximate I/O buffer size. */
 609         if (packet_is_interactive())
 610                 buffer_high = 4096;
 611         else
 612                 buffer_high = 64 * 1024;
 613
 614 #if 0
 615         /* Initialize max_fd to the maximum of the known file descriptors. */
 616         max_fd = MAX(connection_in, connection_out);
 617         max_fd = MAX(max_fd, fdin);
 618         max_fd = MAX(max_fd, fdout);
 619         if (fderr != -1)
 620                 max_fd = MAX(max_fd, fderr);
 621 #endif
 622
 623         /* Initialize Initialize buffers. */
 624         buffer_init(&stdin_buffer);
 625         buffer_init(&stdout_buffer);
 626         buffer_init(&stderr_buffer);
 627
 628         /*
 629          * If we have no separate fderr (which is the case when we have a pty
 630          * - there we cannot make difference between data sent to stdout and
 631          * stderr), indicate that we have seen an EOF from stderr.  This way
 632          * we don't need to check the descriptor everywhere.
 633          */
 634         if (fderr == -1)
 635                 fderr_eof = 1;
 636
 637         server_init_dispatch();
 638
 639         /* Main loop of the server for the interactive session mode. */
 640         for (;;) {
 641
 642                 /* Process buffered packets from the client. */
 643                 process_buffered_input_packets();
 644
 645                 /*
 646                  * If we have received eof, and there is no more pending
 647                  * input data, cause a real eof by closing fdin.
 648                  */
 649                 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
 650                         if (fdin != fdout)
 651                                 close(fdin);
 652                         else
 653                                 shutdown(fdin, SHUT_WR); /* We will no longer send. */
 654                         fdin = -1;
 655                 }
 656                 /* Make packets from buffered stderr data to send to the client. */
 657                 make_packets_from_stderr_data();
 658
 659                 /*
 660                  * Make packets from buffered stdout data to send to the
 661                  * client. If there is very little to send, this arranges to
 662                  * not send them now, but to wait a short while to see if we
 663                  * are getting more data. This is necessary, as some systems
 664                  * wake up readers from a pty after each separate character.
 665                  */
 666                 max_time_milliseconds = 0;
 667                 stdout_buffer_bytes = buffer_len(&stdout_buffer);
 668                 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
 669                     stdout_buffer_bytes != previous_stdout_buffer_bytes) {
 670                         /* try again after a while */
 671                         max_time_milliseconds = 10;
 672                 } else {
 673                         /* Send it now. */
 674                         make_packets_from_stdout_data();
 675                 }
 676                 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
 677
 678                 /* Send channel data to the client. */
 679                 if (packet_not_very_much_data_to_write())
 680                         channel_output_poll();
 681
 682                 /*
 683                  * Bail out of the loop if the program has closed its output
 684                  * descriptors, and we have no more data to send to the
 685                  * client, and there is no pending buffered data.
 686                  */
 687                 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
 688                     buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
 689                         if (!channel_still_open())
 690                                 break;
 691                         if (!waiting_termination) {
 692                                 const char *s = "Waiting for forwarded connections to terminate...\r\n";
 693                                 char *cp;
 694                                 waiting_termination = 1;
 695                                 buffer_append(&stderr_buffer, s, strlen(s));
 696
 697                                 /* Display list of open channels. */
 698                                 cp = channel_open_message();
 699                                 buffer_append(&stderr_buffer, cp, strlen(cp));
 700                                 xfree(cp);
 701                         }
 702                 }
 703                 max_fd = MAX(connection_in, connection_out);
 704                 max_fd = MAX(max_fd, fdin);
 705                 max_fd = MAX(max_fd, fdout);
 706                 max_fd = MAX(max_fd, fderr);
 707                 max_fd = MAX(max_fd, notify_pipe[0]);
 708
 709                 /* Sleep in select() until we can do something. */
 710                 wait_until_can_do_something(&readset, &writeset, &max_fd,
 711                     &nalloc, max_time_milliseconds);
 712
 713                 if (received_sigterm) {
 714                         logit("Exiting on signal %d", received_sigterm);
 715                         /* Clean up sessions, utmp, etc. */
 716                         cleanup_exit(255);
 717                 }
 718
 719                 /* Process any channel events. */
 720                 channel_after_select(readset, writeset);
 721
 722                 /* Process input from the client and from program stdout/stderr. */
 723                 process_input(readset);
 724
 725                 /* Process output to the client and to program stdin. */
 726                 process_output(writeset);
 727         }
 728         if (readset)
 729                 xfree(readset);
 730         if (writeset)
 731                 xfree(writeset);
 732
 733         /* Cleanup and termination code. */
 734
 735         /* Wait until all output has been sent to the client. */
 736         drain_output();
 737
 738         debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
 739             stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
 740
 741         /* Free and clear the buffers. */
 742         buffer_free(&stdin_buffer);
 743         buffer_free(&stdout_buffer);
 744         buffer_free(&stderr_buffer);
 745
 746         /* Close the file descriptors. */
 747         if (fdout != -1)
 748                 close(fdout);
 749         fdout = -1;
 750         fdout_eof = 1;
 751         if (fderr != -1)
 752                 close(fderr);
 753         fderr = -1;
 754         fderr_eof = 1;
 755         if (fdin != -1)
 756                 close(fdin);
 757         fdin = -1;
 758
 759         channel_free_all();
 760
 761         /* We no longer want our SIGCHLD handler to be called. */
 762         mysignal(SIGCHLD, SIG_DFL);
 763
 764         while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
 765                 if (errno != EINTR)
 766                         packet_disconnect("wait: %.100s", strerror(errno));
 767         if (wait_pid != pid)
 768                 error("Strange, wait returned pid %ld, expected %ld",
 769                     (long)wait_pid, (long)pid);
 770
 771         /* Check if it exited normally. */
 772         if (WIFEXITED(wait_status)) {
 773                 /* Yes, normal exit.  Get exit status and send it to the client. */
 774                 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
 775                 packet_start(SSH_SMSG_EXITSTATUS);
 776                 packet_put_int(WEXITSTATUS(wait_status));
 777                 packet_send();
 778                 packet_write_wait();
 779
 780                 /*
 781                  * Wait for exit confirmation.  Note that there might be
 782                  * other packets coming before it; however, the program has
 783                  * already died so we just ignore them.  The client is
 784                  * supposed to respond with the confirmation when it receives
 785                  * the exit status.
 786                  */
 787                 do {
 788                         type = packet_read();
 789                 }
 790                 while (type != SSH_CMSG_EXIT_CONFIRMATION);
 791
 792                 debug("Received exit confirmation.");
 793                 return;
 794         }
 795         /* Check if the program terminated due to a signal. */
 796         if (WIFSIGNALED(wait_status))
 797                 packet_disconnect("Command terminated on signal %d.",
 798                                   WTERMSIG(wait_status));
 799
 800         /* Some weird exit cause.  Just exit. */
 801         packet_disconnect("wait returned status %04x.", wait_status);
 802         /* NOTREACHED */
 803 }
 804
 805 static void
 806 collect_children(void)
 807 {
 808         pid_t pid;
 809         sigset_t oset, nset;
 810         int status;
 811
 812         /* block SIGCHLD while we check for dead children */
 813         sigemptyset(&nset);
 814         sigaddset(&nset, SIGCHLD);
 815         sigprocmask(SIG_BLOCK, &nset, &oset);
 816         if (child_terminated) {
 817                 debug("Received SIGCHLD.");
 818                 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
 819                     (pid < 0 && errno == EINTR))
 820                         if (pid > 0)
 821                                 session_close_by_pid(pid, status);
 822                 child_terminated = 0;
 823         }
 824         sigprocmask(SIG_SETMASK, &oset, NULL);
 825 }
 826
 827 void
 828 server_loop2(Authctxt *authctxt)
 829 {
 830         fd_set *readset = NULL, *writeset = NULL;
 831         int rekeying = 0, max_fd, nalloc = 0;
 832         double start_time, total_time;
 833
 834         debug("Entering interactive session for SSH2.");
 835         start_time = get_current_time();
 836
 837         mysignal(SIGCHLD, sigchld_handler);
 838         child_terminated = 0;
 839         connection_in = packet_get_connection_in();
 840         connection_out = packet_get_connection_out();
 841
 842         if (!use_privsep) {
 843                 signal(SIGTERM, sigterm_handler);
 844                 signal(SIGINT, sigterm_handler);
 845                 signal(SIGQUIT, sigterm_handler);
 846         }
 847
 848         notify_setup();
 849
 850         max_fd = MAX(connection_in, connection_out);
 851         max_fd = MAX(max_fd, notify_pipe[0]);
 852
 853         server_init_dispatch();
 854
 855         for (;;) {
 856                 process_buffered_input_packets();
 857
 858                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
 859
 860                 if (!rekeying && packet_not_very_much_data_to_write())
 861                         channel_output_poll();
 862                 wait_until_can_do_something(&readset, &writeset, &max_fd,
 863                     &nalloc, 0);
 864
 865                 if (received_sigterm) {
 866                         logit("Exiting on signal %d", received_sigterm);
 867                         /* Clean up sessions, utmp, etc. */
 868                         cleanup_exit(255);
 869                 }
 870
 871                 collect_children();
 872                 if (!rekeying) {
 873                         channel_after_select(readset, writeset);
 874                         if (packet_need_rekeying()) {
 875                                 debug("need rekeying");
 876                                 xxx_kex->done = 0;
 877                                 kex_send_kexinit(xxx_kex);
 878                         }
 879                 }
 880                 process_input(readset);
 881                 if (connection_closed)
 882                         break;
 883                 process_output(writeset);
 884         }
 885         collect_children();
 886
 887         if (readset)
 888                 xfree(readset);
 889         if (writeset)
 890                 xfree(writeset);
 891
 892         /* free all channels, no more reads and writes */
 893         channel_free_all();
 894
 895         /* free remaining sessions, e.g. remove wtmp entries */
 896         session_destroy_all(NULL);
 897         total_time = get_current_time() - start_time;
 898         logit("SSH: Server;LType: Throughput;Remote: %s-%d;IN: %lu;OUT: %lu;Duration: %.1f;tPut_in: %.1f;tPut_out: %.1f",
 899               get_remote_ipaddr(), get_remote_port(),
 900               stdin_bytes, fdout_bytes, total_time, stdin_bytes / total_time,
 901               fdout_bytes / total_time);
 902 }
 903
 904 static void
 905 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
 906 {
 907         debug("Got %d/%u for keepalive", type, seq);
 908         /*
 909          * reset timeout, since we got a sane answer from the client.
 910          * even if this was generated by something other than
 911          * the bogus CHANNEL_REQUEST we send for keepalives.
 912          */
 913         client_alive_timeouts = 0;
 914 }
 915
 916 static void
 917 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
 918 {
 919         char *data;
 920         u_int data_len;
 921
 922         /* Stdin data from the client.  Append it to the buffer. */
 923         /* Ignore any data if the client has closed stdin. */
 924         if (fdin == -1)
 925                 return;
 926         data = packet_get_string(&data_len);
 927         packet_check_eom();
 928         buffer_append(&stdin_buffer, data, data_len);
 929         memset(data, 0, data_len);
 930         xfree(data);
 931 }
 932
 933 static void
 934 server_input_eof(int type, u_int32_t seq, void *ctxt)
 935 {
 936         /*
 937          * Eof from the client.  The stdin descriptor to the
 938          * program will be closed when all buffered data has
 939          * drained.
 940          */
 941         debug("EOF received for stdin.");
 942         packet_check_eom();
 943         stdin_eof = 1;
 944 }
 945
 946 static void
 947 server_input_window_size(int type, u_int32_t seq, void *ctxt)
 948 {
 949         u_int row = packet_get_int();
 950         u_int col = packet_get_int();
 951         u_int xpixel = packet_get_int();
 952         u_int ypixel = packet_get_int();
 953
 954         debug("Window change received.");
 955         packet_check_eom();
 956         if (fdin != -1)
 957                 pty_change_window_size(fdin, row, col, xpixel, ypixel);
 958 }
 959
 960 static Channel *
 961 server_request_direct_tcpip(void)
 962 {
 963         Channel *c;
 964         int sock;
 965         char *target, *originator;
 966         int target_port, originator_port;
 967
 968         target = packet_get_string(NULL);
 969         target_port = packet_get_int();
 970         originator = packet_get_string(NULL);
 971         originator_port = packet_get_int();
 972         packet_check_eom();
 973
 974         debug("server_request_direct_tcpip: originator %s port %d, target %s port %d",
 975             originator, originator_port, target, target_port);
 976
 977         /* XXX check permission */
 978         sock = channel_connect_to(target, target_port);
 979         xfree(target);
 980         xfree(originator);
 981         if (sock < 0)
 982                 return NULL;
 983         if (options.hpn_disabled)
 984         c = channel_new("direct-tcpip", SSH_CHANNEL_CONNECTING,
 985             sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
 986             CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1);
 987         else
 988                 c = channel_new("direct-tcpip", SSH_CHANNEL_CONNECTING,
 989                     sock, sock, -1, options.hpn_buffer_size,
 990                     CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1);
 991         return c;
 992 }
 993
 994 static Channel *
 995 server_request_tun(void)
 996 {
 997         Channel *c = NULL;
 998         int mode, tun;
 999         int sock;
1000
1001         mode = packet_get_int();
1002         switch (mode) {
1003         case SSH_TUNMODE_POINTOPOINT:
1004         case SSH_TUNMODE_ETHERNET:
1005                 break;
1006         default:
1007                 packet_send_debug("Unsupported tunnel device mode.");
1008                 return NULL;
1009         }
1010         if ((options.permit_tun & mode) == 0) {
1011                 packet_send_debug("Server has rejected tunnel device "
1012                     "forwarding");
1013                 return NULL;
1014         }
1015
1016         tun = packet_get_int();
1017         if (forced_tun_device != -1) {
1018                 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1019                         goto done;
1020                 tun = forced_tun_device;
1021         }
1022         sock = tun_open(tun, mode);
1023         if (sock < 0)
1024                 goto done;
1025         if (options.hpn_disabled)
1026         c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1027             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1028         else
1029                 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1030                     options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1031         c->datagram = 1;
1032 #if defined(SSH_TUN_FILTER)
1033         if (mode == SSH_TUNMODE_POINTOPOINT)
1034                 channel_register_filter(c->self, sys_tun_infilter,
1035                     sys_tun_outfilter);
1036 #endif
1037
1038  done:
1039         if (c == NULL)
1040                 packet_send_debug("Failed to open the tunnel device.");
1041         return c;
1042 }
1043
1044 static Channel *
1045 server_request_session(void)
1046 {
1047         Channel *c;
1048
1049         debug("input_session_request");
1050         packet_check_eom();
1051         /*
1052          * A server session has no fd to read or write until a
1053          * CHANNEL_REQUEST for a shell is made, so we set the type to
1054          * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
1055          * CHANNEL_REQUEST messages is registered.
1056          */
1057         c = channel_new("session", SSH_CHANNEL_LARVAL,
1058             -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1059             0, "server-session", 1);
1060         if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled))
1061                 c->dynamic_window = 1;
1062         if (session_open(the_authctxt, c->self) != 1) {
1063                 debug("session open failed, free channel %d", c->self);
1064                 channel_free(c);
1065                 return NULL;
1066         }
1067         channel_register_cleanup(c->self, session_close_by_channel, 0);
1068         return c;
1069 }
1070
1071 static void
1072 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1073 {
1074         Channel *c = NULL;
1075         char *ctype;
1076         int rchan;
1077         u_int rmaxpack, rwindow, len;
1078
1079         ctype = packet_get_string(&len);
1080         rchan = packet_get_int();
1081         rwindow = packet_get_int();
1082         rmaxpack = packet_get_int();
1083
1084         debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1085             ctype, rchan, rwindow, rmaxpack);
1086
1087         if (strcmp(ctype, "session") == 0) {
1088                 c = server_request_session();
1089         } else if (strcmp(ctype, "direct-tcpip") == 0) {
1090                 c = server_request_direct_tcpip();
1091         } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1092                 c = server_request_tun();
1093         }
1094         if (c != NULL) {
1095                 debug("server_input_channel_open: confirm %s", ctype);
1096                 c->remote_id = rchan;
1097                 c->remote_window = rwindow;
1098                 c->remote_maxpacket = rmaxpack;
1099                 if (c->type != SSH_CHANNEL_CONNECTING) {
1100                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1101                         packet_put_int(c->remote_id);
1102                         packet_put_int(c->self);
1103                         packet_put_int(c->local_window);
1104                         packet_put_int(c->local_maxpacket);
1105                         packet_send();
1106                 }
1107         } else {
1108                 debug("server_input_channel_open: failure %s", ctype);
1109                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1110                 packet_put_int(rchan);
1111                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1112                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1113                         packet_put_cstring("open failed");
1114                         packet_put_cstring("");
1115                 }
1116                 packet_send();
1117         }
1118         xfree(ctype);
1119 }
1120
1121 static void
1122 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1123 {
1124         char *rtype;
1125         int want_reply;
1126         int success = 0;
1127
1128         rtype = packet_get_string(NULL);
1129         want_reply = packet_get_char();
1130         debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1131
1132         /* -R style forwarding */
1133         if (strcmp(rtype, "tcpip-forward") == 0) {
1134                 struct passwd *pw;
1135                 char *listen_address;
1136                 u_short listen_port;
1137
1138                 pw = the_authctxt->pw;
1139                 if (pw == NULL || !the_authctxt->valid)
1140                         fatal("server_input_global_request: no/invalid user");
1141                 listen_address = packet_get_string(NULL);
1142                 listen_port = (u_short)packet_get_int();
1143                 debug("server_input_global_request: tcpip-forward listen %s port %d",
1144                     listen_address, listen_port);
1145
1146                 /* check permissions */
1147                 if (!options.allow_tcp_forwarding ||
1148                     no_port_forwarding_flag
1149 #ifndef NO_IPPORT_RESERVED_CONCEPT
1150                     || (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)
1151 #endif
1152                     ) {
1153                         success = 0;
1154                         packet_send_debug("Server has disabled port forwarding.");
1155                 } else {
1156                         /* Start listening on the port */
1157                         success = channel_setup_remote_fwd_listener(
1158                             listen_address, listen_port, options.gateway_ports,
1159                             options.hpn_disabled, options.hpn_buffer_size);
1160                 }
1161                 xfree(listen_address);
1162         } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1163                 char *cancel_address;
1164                 u_short cancel_port;
1165
1166                 cancel_address = packet_get_string(NULL);
1167                 cancel_port = (u_short)packet_get_int();
1168                 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1169                     cancel_address, cancel_port);
1170
1171                 success = channel_cancel_rport_listener(cancel_address,
1172                     cancel_port);
1173                 xfree(cancel_address);
1174         }
1175         if (want_reply) {
1176                 packet_start(success ?
1177                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1178                 packet_send();
1179                 packet_write_wait();
1180         }
1181         xfree(rtype);
1182 }
1183
1184 static void
1185 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1186 {
1187         Channel *c;
1188         int id, reply, success = 0;
1189         char *rtype;
1190
1191         id = packet_get_int();
1192         rtype = packet_get_string(NULL);
1193         reply = packet_get_char();
1194
1195         debug("server_input_channel_req: channel %d request %s reply %d",
1196             id, rtype, reply);
1197
1198         if ((c = channel_lookup(id)) == NULL)
1199                 packet_disconnect("server_input_channel_req: "
1200                     "unknown channel %d", id);
1201         if (c->type == SSH_CHANNEL_LARVAL || c->type == SSH_CHANNEL_OPEN)
1202                 success = session_input_channel_req(c, rtype);
1203         if (reply) {
1204                 packet_start(success ?
1205                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1206                 packet_put_int(c->remote_id);
1207                 packet_send();
1208         }
1209         xfree(rtype);
1210 }
1211
1212 static void
1213 server_init_dispatch_20(void)
1214 {
1215         debug("server_init_dispatch_20");
1216         dispatch_init(&dispatch_protocol_error);
1217         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1218         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1219         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1220         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1221         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1222         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1223         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1224         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1225         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1226         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1227         /* client_alive */
1228         dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1229         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1230         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1231         /* rekeying */
1232         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1233 }
1234 static void
1235 server_init_dispatch_13(void)
1236 {
1237         debug("server_init_dispatch_13");
1238         dispatch_init(NULL);
1239         dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1240         dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1241         dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1242         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1243         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1244         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1245         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1246         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1247         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1248 }
1249 static void
1250 server_init_dispatch_15(void)
1251 {
1252         server_init_dispatch_13();
1253         debug("server_init_dispatch_15");
1254         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1255         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1256 }
1257 static void
1258 server_init_dispatch(void)
1259 {
1260         if (compat20)
1261                 server_init_dispatch_20();
1262         else if (compat13)
1263                 server_init_dispatch_13();
1264         else
1265                 server_init_dispatch_15();
1266 }