openssh/serverloop.c

   1 /* $OpenBSD: serverloop.c,v 1.148 2008/02/22 20:44:02 dtucker 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
 108 /*
 109  * This SIGCHLD kludge is used to detect when the child exits.  The server
 110  * will exit after that, as soon as forwarded connections have terminated.
 111  */
 112
 113 static volatile sig_atomic_t child_terminated = 0;      /* The child has terminated. */
 114
 115 /* Cleanup on signals (!use_privsep case only) */
 116 static volatile sig_atomic_t received_sigterm = 0;
 117
 118 /* prototypes */
 119 static void server_init_dispatch(void);
 120
 121 /*
 122  * Returns current time in seconds from Jan 1, 1970 with the maximum
 123  * available resolution.
 124  */
 125
 126 static double
 127 get_current_time(void)
 128 {
 129         struct timeval tv;
 130         gettimeofday(&tv, NULL);
 131         return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
 132 }
 133
 134
 135 /*
 136  * we write to this pipe if a SIGCHLD is caught in order to avoid
 137  * the race between select() and child_terminated
 138  */
 139 static int notify_pipe[2];
 140 static void
 141 notify_setup(void)
 142 {
 143         if (pipe(notify_pipe) < 0) {
 144                 error("pipe(notify_pipe) failed %s", strerror(errno));
 145         } else if ((fcntl(notify_pipe[0], F_SETFD, 1) == -1) ||
 146             (fcntl(notify_pipe[1], F_SETFD, 1) == -1)) {
 147                 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
 148                 close(notify_pipe[0]);
 149                 close(notify_pipe[1]);
 150         } else {
 151                 set_nonblock(notify_pipe[0]);
 152                 set_nonblock(notify_pipe[1]);
 153                 return;
 154         }
 155         notify_pipe[0] = -1;    /* read end */
 156         notify_pipe[1] = -1;    /* write end */
 157 }
 158 static void
 159 notify_parent(void)
 160 {
 161         if (notify_pipe[1] != -1)
 162                 write(notify_pipe[1], "", 1);
 163 }
 164 static void
 165 notify_prepare(fd_set *readset)
 166 {
 167         if (notify_pipe[0] != -1)
 168                 FD_SET(notify_pipe[0], readset);
 169 }
 170 static void
 171 notify_done(fd_set *readset)
 172 {
 173         char c;
 174
 175         if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
 176                 while (read(notify_pipe[0], &c, 1) != -1)
 177                         debug2("notify_done: reading");
 178 }
 179
 180 /*ARGSUSED*/
 181 static void
 182 sigchld_handler(int sig)
 183 {
 184         int save_errno = errno;
 185         child_terminated = 1;
 186 #ifndef _UNICOS
 187         mysignal(SIGCHLD, sigchld_handler);
 188 #endif
 189         notify_parent();
 190         errno = save_errno;
 191 }
 192
 193 /*ARGSUSED*/
 194 static void
 195 sigterm_handler(int sig)
 196 {
 197         received_sigterm = sig;
 198 }
 199
 200 /*
 201  * Make packets from buffered stderr data, and buffer it for sending
 202  * to the client.
 203  */
 204 static void
 205 make_packets_from_stderr_data(void)
 206 {
 207         u_int len;
 208
 209         /* Send buffered stderr data to the client. */
 210         while (buffer_len(&stderr_buffer) > 0 &&
 211             packet_not_very_much_data_to_write()) {
 212                 len = buffer_len(&stderr_buffer);
 213                 if (packet_is_interactive()) {
 214                         if (len > 512)
 215                                 len = 512;
 216                 } else {
 217                         /* Keep the packets at reasonable size. */
 218                         if (len > packet_get_maxsize())
 219                                 len = packet_get_maxsize();
 220                 }
 221                 packet_start(SSH_SMSG_STDERR_DATA);
 222                 packet_put_string(buffer_ptr(&stderr_buffer), len);
 223                 packet_send();
 224                 buffer_consume(&stderr_buffer, len);
 225                 stderr_bytes += len;
 226         }
 227 }
 228
 229 /*
 230  * Make packets from buffered stdout data, and buffer it for sending to the
 231  * client.
 232  */
 233 static void
 234 make_packets_from_stdout_data(void)
 235 {
 236         u_int len;
 237
 238         /* Send buffered stdout data to the client. */
 239         while (buffer_len(&stdout_buffer) > 0 &&
 240             packet_not_very_much_data_to_write()) {
 241                 len = buffer_len(&stdout_buffer);
 242                 if (packet_is_interactive()) {
 243                         if (len > 512)
 244                                 len = 512;
 245                 } else {
 246                         /* Keep the packets at reasonable size. */
 247                         if (len > packet_get_maxsize())
 248                                 len = packet_get_maxsize();
 249                 }
 250                 packet_start(SSH_SMSG_STDOUT_DATA);
 251                 packet_put_string(buffer_ptr(&stdout_buffer), len);
 252                 packet_send();
 253                 buffer_consume(&stdout_buffer, len);
 254                 stdout_bytes += len;
 255         }
 256 }
 257
 258 static void
 259 client_alive_check(void)
 260 {
 261         int channel_id;
 262
 263         /* timeout, check to see how many we have had */
 264         if (++keep_alive_timeouts > options.client_alive_count_max) {
 265                 logit("Timeout, client not responding.");
 266                 cleanup_exit(255);
 267         }
 268
 269         /*
 270          * send a bogus global/channel request with "wantreply",
 271          * we should get back a failure
 272          */
 273         if ((channel_id = channel_find_open()) == -1) {
 274                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
 275                 packet_put_cstring("keepalive@openssh.com");
 276                 packet_put_char(1);     /* boolean: want reply */
 277         } else {
 278                 channel_request_start(channel_id, "keepalive@openssh.com", 1);
 279         }
 280         packet_send();
 281 }
 282
 283 /*
 284  * Sleep in select() until we can do something.  This will initialize the
 285  * select masks.  Upon return, the masks will indicate which descriptors
 286  * have data or can accept data.  Optionally, a maximum time can be specified
 287  * for the duration of the wait (0 = infinite).
 288  */
 289 static void
 290 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
 291     u_int *nallocp, u_int max_time_milliseconds)
 292 {
 293         struct timeval tv, *tvp;
 294         int ret;
 295         int client_alive_scheduled = 0;
 296         int program_alive_scheduled = 0;
 297
 298         /*
 299          * if using client_alive, set the max timeout accordingly,
 300          * and indicate that this particular timeout was for client
 301          * alive by setting the client_alive_scheduled flag.
 302          *
 303          * this could be randomized somewhat to make traffic
 304          * analysis more difficult, but we're not doing it yet.
 305          */
 306         if (compat20 &&
 307             max_time_milliseconds == 0 && options.client_alive_interval) {
 308                 client_alive_scheduled = 1;
 309                 max_time_milliseconds = options.client_alive_interval * 1000;
 310         }
 311
 312         /* Allocate and update select() masks for channel descriptors. */
 313         channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
 314
 315         if (compat20) {
 316 #if 0
 317                 /* wrong: bad condition XXX */
 318                 if (channel_not_very_much_buffered_data())
 319 #endif
 320                 FD_SET(connection_in, *readsetp);
 321         } else {
 322                 /*
 323                  * Read packets from the client unless we have too much
 324                  * buffered stdin or channel data.
 325                  */
 326                 if (buffer_len(&stdin_buffer) < buffer_high &&
 327                     channel_not_very_much_buffered_data())
 328                         FD_SET(connection_in, *readsetp);
 329                 /*
 330                  * If there is not too much data already buffered going to
 331                  * the client, try to get some more data from the program.
 332                  */
 333                 if (packet_not_very_much_data_to_write()) {
 334                         program_alive_scheduled = child_terminated;
 335                         if (!fdout_eof)
 336                                 FD_SET(fdout, *readsetp);
 337                         if (!fderr_eof)
 338                                 FD_SET(fderr, *readsetp);
 339                 }
 340                 /*
 341                  * If we have buffered data, try to write some of that data
 342                  * to the program.
 343                  */
 344                 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
 345                         FD_SET(fdin, *writesetp);
 346         }
 347         notify_prepare(*readsetp);
 348
 349         /*
 350          * If we have buffered packet data going to the client, mark that
 351          * descriptor.
 352          */
 353         if (packet_have_data_to_write())
 354                 FD_SET(connection_out, *writesetp);
 355
 356         /*
 357          * If child has terminated and there is enough buffer space to read
 358          * from it, then read as much as is available and exit.
 359          */
 360         if (child_terminated && packet_not_very_much_data_to_write())
 361                 if (max_time_milliseconds == 0 || client_alive_scheduled)
 362                         max_time_milliseconds = 100;
 363
 364         if (max_time_milliseconds == 0)
 365                 tvp = NULL;
 366         else {
 367                 tv.tv_sec = max_time_milliseconds / 1000;
 368                 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
 369                 tvp = &tv;
 370         }
 371
 372         /* Wait for something to happen, or the timeout to expire. */
 373         ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 374
 375         if (ret == -1) {
 376                 memset(*readsetp, 0, *nallocp);
 377                 memset(*writesetp, 0, *nallocp);
 378                 if (errno != EINTR)
 379                         error("select: %.100s", strerror(errno));
 380         } else {
 381                 if (ret == 0 && client_alive_scheduled)
 382                         client_alive_check();
 383                 if (!compat20 && program_alive_scheduled && fdin_is_tty) {
 384                         if (!fdout_eof)
 385                                 FD_SET(fdout, *readsetp);
 386                         if (!fderr_eof)
 387                                 FD_SET(fderr, *readsetp);
 388                 }
 389         }
 390
 391         notify_done(*readsetp);
 392 }
 393
 394 /*
 395  * Processes input from the client and the program.  Input data is stored
 396  * in buffers and processed later.
 397  */
 398 static void
 399 process_input(fd_set *readset)
 400 {
 401         int len;
 402         char buf[16384];
 403
 404         /* Read and buffer any input data from the client. */
 405         if (FD_ISSET(connection_in, readset)) {
 406                 len = read(connection_in, buf, sizeof(buf));
 407                 if (len == 0) {
 408                         verbose("Connection closed by %.100s",
 409                             get_remote_ipaddr());
 410                         connection_closed = 1;
 411                         if (compat20)
 412                                 return;
 413                         cleanup_exit(255);
 414                 } else if (len < 0) {
 415                         if (errno != EINTR && errno != EAGAIN) {
 416                                 verbose("Read error from remote host "
 417                                     "%.100s: %.100s",
 418                                     get_remote_ipaddr(), strerror(errno));
 419                                 cleanup_exit(255);
 420                         }
 421                 } else {
 422                         /* Buffer any received data. */
 423                         packet_process_incoming(buf, len);
 424                         fdout_bytes += len;
 425                 }
 426         }
 427         if (compat20)
 428                 return;
 429
 430         /* Read and buffer any available stdout data from the program. */
 431         if (!fdout_eof && FD_ISSET(fdout, readset)) {
 432                 errno = 0;
 433                 len = read(fdout, buf, sizeof(buf));
 434                 if (len < 0 && (errno == EINTR ||
 435                     (errno == EAGAIN && !child_terminated))) {
 436                         /* do nothing */
 437 #ifndef PTY_ZEROREAD
 438                 } else if (len <= 0) {
 439 #else
 440                 } else if ((!isatty(fdout) && len <= 0) ||
 441                     (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
 442 #endif
 443                         fdout_eof = 1;
 444                 } else {
 445                         buffer_append(&stdout_buffer, buf, len);
 446                         fdout_bytes += len;
 447                         debug ("FD out now: %ld", fdout_bytes);
 448                 }
 449         }
 450         /* Read and buffer any available stderr data from the program. */
 451         if (!fderr_eof && FD_ISSET(fderr, readset)) {
 452                 errno = 0;
 453                 len = read(fderr, buf, sizeof(buf));
 454                 if (len < 0 && (errno == EINTR ||
 455                     (errno == EAGAIN && !child_terminated))) {
 456                         /* do nothing */
 457 #ifndef PTY_ZEROREAD
 458                 } else if (len <= 0) {
 459 #else
 460                 } else if ((!isatty(fderr) && len <= 0) ||
 461                     (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
 462 #endif
 463                         fderr_eof = 1;
 464                 } else {
 465                         buffer_append(&stderr_buffer, buf, len);
 466                 }
 467         }
 468 }
 469
 470 /*
 471  * Sends data from internal buffers to client program stdin.
 472  */
 473 static void
 474 process_output(fd_set *writeset)
 475 {
 476         struct termios tio;
 477         u_char *data;
 478         u_int dlen;
 479         int len;
 480
 481         /* Write buffered data to program stdin. */
 482         if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
 483                 data = buffer_ptr(&stdin_buffer);
 484                 dlen = buffer_len(&stdin_buffer);
 485                 len = write(fdin, data, dlen);
 486                 if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
 487                         /* do nothing */
 488                 } else if (len <= 0) {
 489                         if (fdin != fdout)
 490                                 close(fdin);
 491                         else
 492                                 shutdown(fdin, SHUT_WR); /* We will no longer send. */
 493                         fdin = -1;
 494                 } else {
 495                         /* Successful write. */
 496                         if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
 497                             tcgetattr(fdin, &tio) == 0 &&
 498                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
 499                                 /*
 500                                  * Simulate echo to reduce the impact of
 501                                  * traffic analysis
 502                                  */
 503                                 packet_send_ignore(len);
 504                                 packet_send();
 505                         }
 506                         /* Consume the data from the buffer. */
 507                         buffer_consume(&stdin_buffer, len);
 508                         /* Update the count of bytes written to the program. */
 509                         stdin_bytes += len;
 510                 }
 511         }
 512         /* Send any buffered packet data to the client. */
 513         if (FD_ISSET(connection_out, writeset))
 514                 stdin_bytes += packet_write_poll();
 515 }
 516
 517 /*
 518  * Wait until all buffered output has been sent to the client.
 519  * This is used when the program terminates.
 520  */
 521 static void
 522 drain_output(void)
 523 {
 524         /* Send any buffered stdout data to the client. */
 525         if (buffer_len(&stdout_buffer) > 0) {
 526                 packet_start(SSH_SMSG_STDOUT_DATA);
 527                 packet_put_string(buffer_ptr(&stdout_buffer),
 528                                   buffer_len(&stdout_buffer));
 529                 packet_send();
 530                 /* Update the count of sent bytes. */
 531                 stdout_bytes += buffer_len(&stdout_buffer);
 532         }
 533         /* Send any buffered stderr data to the client. */
 534         if (buffer_len(&stderr_buffer) > 0) {
 535                 packet_start(SSH_SMSG_STDERR_DATA);
 536                 packet_put_string(buffer_ptr(&stderr_buffer),
 537                                   buffer_len(&stderr_buffer));
 538                 packet_send();
 539                 /* Update the count of sent bytes. */
 540                 stderr_bytes += buffer_len(&stderr_buffer);
 541         }
 542         /* Wait until all buffered data has been written to the client. */
 543         packet_write_wait();
 544 }
 545
 546 static void
 547 process_buffered_input_packets(void)
 548 {
 549         dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
 550 }
 551
 552 /*
 553  * Performs the interactive session.  This handles data transmission between
 554  * the client and the program.  Note that the notion of stdin, stdout, and
 555  * stderr in this function is sort of reversed: this function writes to
 556  * stdin (of the child program), and reads from stdout and stderr (of the
 557  * child program).
 558  */
 559 void
 560 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
 561 {
 562         fd_set *readset = NULL, *writeset = NULL;
 563         int max_fd = 0;
 564         u_int nalloc = 0;
 565         int wait_status;        /* Status returned by wait(). */
 566         pid_t wait_pid;         /* pid returned by wait(). */
 567         int waiting_termination = 0;    /* Have displayed waiting close message. */
 568         u_int max_time_milliseconds;
 569         u_int previous_stdout_buffer_bytes;
 570         u_int stdout_buffer_bytes;
 571         int type;
 572
 573         debug("Entering interactive session.");
 574
 575         /* Initialize the SIGCHLD kludge. */
 576         child_terminated = 0;
 577         mysignal(SIGCHLD, sigchld_handler);
 578
 579         if (!use_privsep) {
 580                 signal(SIGTERM, sigterm_handler);
 581                 signal(SIGINT, sigterm_handler);
 582                 signal(SIGQUIT, sigterm_handler);
 583         }
 584
 585         /* Initialize our global variables. */
 586         fdin = fdin_arg;
 587         fdout = fdout_arg;
 588         fderr = fderr_arg;
 589
 590         /* nonblocking IO */
 591         set_nonblock(fdin);
 592         set_nonblock(fdout);
 593         /* we don't have stderr for interactive terminal sessions, see below */
 594         if (fderr != -1)
 595                 set_nonblock(fderr);
 596
 597         if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
 598                 fdin_is_tty = 1;
 599
 600         connection_in = packet_get_connection_in();
 601         connection_out = packet_get_connection_out();
 602
 603         notify_setup();
 604
 605         previous_stdout_buffer_bytes = 0;
 606
 607         /* Set approximate I/O buffer size. */
 608         if (packet_is_interactive())
 609                 buffer_high = 4096;
 610         else
 611                 buffer_high = 64 * 1024;
 612
 613 #if 0
 614         /* Initialize max_fd to the maximum of the known file descriptors. */
 615         max_fd = MAX(connection_in, connection_out);
 616         max_fd = MAX(max_fd, fdin);
 617         max_fd = MAX(max_fd, fdout);
 618         if (fderr != -1)
 619                 max_fd = MAX(max_fd, fderr);
 620 #endif
 621
 622         /* Initialize Initialize buffers. */
 623         buffer_init(&stdin_buffer);
 624         buffer_init(&stdout_buffer);
 625         buffer_init(&stderr_buffer);
 626
 627         /*
 628          * If we have no separate fderr (which is the case when we have a pty
 629          * - there we cannot make difference between data sent to stdout and
 630          * stderr), indicate that we have seen an EOF from stderr.  This way
 631          * we don't need to check the descriptor everywhere.
 632          */
 633         if (fderr == -1)
 634                 fderr_eof = 1;
 635
 636         server_init_dispatch();
 637
 638         /* Main loop of the server for the interactive session mode. */
 639         for (;;) {
 640
 641                 /* Process buffered packets from the client. */
 642                 process_buffered_input_packets();
 643
 644                 /*
 645                  * If we have received eof, and there is no more pending
 646                  * input data, cause a real eof by closing fdin.
 647                  */
 648                 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
 649                         if (fdin != fdout)
 650                                 close(fdin);
 651                         else
 652                                 shutdown(fdin, SHUT_WR); /* We will no longer send. */
 653                         fdin = -1;
 654                 }
 655                 /* Make packets from buffered stderr data to send to the client. */
 656                 make_packets_from_stderr_data();
 657
 658                 /*
 659                  * Make packets from buffered stdout data to send to the
 660                  * client. If there is very little to send, this arranges to
 661                  * not send them now, but to wait a short while to see if we
 662                  * are getting more data. This is necessary, as some systems
 663                  * wake up readers from a pty after each separate character.
 664                  */
 665                 max_time_milliseconds = 0;
 666                 stdout_buffer_bytes = buffer_len(&stdout_buffer);
 667                 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
 668                     stdout_buffer_bytes != previous_stdout_buffer_bytes) {
 669                         /* try again after a while */
 670                         max_time_milliseconds = 10;
 671                 } else {
 672                         /* Send it now. */
 673                         make_packets_from_stdout_data();
 674                 }
 675                 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
 676
 677                 /* Send channel data to the client. */
 678                 if (packet_not_very_much_data_to_write())
 679                         channel_output_poll();
 680
 681                 /*
 682                  * Bail out of the loop if the program has closed its output
 683                  * descriptors, and we have no more data to send to the
 684                  * client, and there is no pending buffered data.
 685                  */
 686                 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
 687                     buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
 688                         if (!channel_still_open())
 689                                 break;
 690                         if (!waiting_termination) {
 691                                 const char *s = "Waiting for forwarded connections to terminate...\r\n";
 692                                 char *cp;
 693                                 waiting_termination = 1;
 694                                 buffer_append(&stderr_buffer, s, strlen(s));
 695
 696                                 /* Display list of open channels. */
 697                                 cp = channel_open_message();
 698                                 buffer_append(&stderr_buffer, cp, strlen(cp));
 699                                 xfree(cp);
 700                         }
 701                 }
 702                 max_fd = MAX(connection_in, connection_out);
 703                 max_fd = MAX(max_fd, fdin);
 704                 max_fd = MAX(max_fd, fdout);
 705                 max_fd = MAX(max_fd, fderr);
 706                 max_fd = MAX(max_fd, notify_pipe[0]);
 707
 708                 /* Sleep in select() until we can do something. */
 709                 wait_until_can_do_something(&readset, &writeset, &max_fd,
 710                     &nalloc, max_time_milliseconds);
 711
 712                 if (received_sigterm) {
 713                         logit("Exiting on signal %d", received_sigterm);
 714                         /* Clean up sessions, utmp, etc. */
 715                         cleanup_exit(255);
 716                 }
 717
 718                 /* Process any channel events. */
 719                 channel_after_select(readset, writeset);
 720
 721                 /* Process input from the client and from program stdout/stderr. */
 722                 process_input(readset);
 723
 724                 /* Process output to the client and to program stdin. */
 725                 process_output(writeset);
 726         }
 727         if (readset)
 728                 xfree(readset);
 729         if (writeset)
 730                 xfree(writeset);
 731
 732         /* Cleanup and termination code. */
 733
 734         /* Wait until all output has been sent to the client. */
 735         drain_output();
 736
 737         debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
 738             stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
 739
 740         /* Free and clear the buffers. */
 741         buffer_free(&stdin_buffer);
 742         buffer_free(&stdout_buffer);
 743         buffer_free(&stderr_buffer);
 744
 745         /* Close the file descriptors. */
 746         if (fdout != -1)
 747                 close(fdout);
 748         fdout = -1;
 749         fdout_eof = 1;
 750         if (fderr != -1)
 751                 close(fderr);
 752         fderr = -1;
 753         fderr_eof = 1;
 754         if (fdin != -1)
 755                 close(fdin);
 756         fdin = -1;
 757
 758         channel_free_all();
 759
 760         /* We no longer want our SIGCHLD handler to be called. */
 761         mysignal(SIGCHLD, SIG_DFL);
 762
 763         while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
 764                 if (errno != EINTR)
 765                         packet_disconnect("wait: %.100s", strerror(errno));
 766         if (wait_pid != pid)
 767                 error("Strange, wait returned pid %ld, expected %ld",
 768                     (long)wait_pid, (long)pid);
 769
 770         /* Check if it exited normally. */
 771         if (WIFEXITED(wait_status)) {
 772                 /* Yes, normal exit.  Get exit status and send it to the client. */
 773                 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
 774                 packet_start(SSH_SMSG_EXITSTATUS);
 775                 packet_put_int(WEXITSTATUS(wait_status));
 776                 packet_send();
 777                 packet_write_wait();
 778
 779                 /*
 780                  * Wait for exit confirmation.  Note that there might be
 781                  * other packets coming before it; however, the program has
 782                  * already died so we just ignore them.  The client is
 783                  * supposed to respond with the confirmation when it receives
 784                  * the exit status.
 785                  */
 786                 do {
 787                         type = packet_read();
 788                 }
 789                 while (type != SSH_CMSG_EXIT_CONFIRMATION);
 790
 791                 debug("Received exit confirmation.");
 792                 return;
 793         }
 794         /* Check if the program terminated due to a signal. */
 795         if (WIFSIGNALED(wait_status))
 796                 packet_disconnect("Command terminated on signal %d.",
 797                                   WTERMSIG(wait_status));
 798
 799         /* Some weird exit cause.  Just exit. */
 800         packet_disconnect("wait returned status %04x.", wait_status);
 801         /* NOTREACHED */
 802 }
 803
 804 static void
 805 collect_children(void)
 806 {
 807         pid_t pid;
 808         sigset_t oset, nset;
 809         int status;
 810
 811         /* block SIGCHLD while we check for dead children */
 812         sigemptyset(&nset);
 813         sigaddset(&nset, SIGCHLD);
 814         sigprocmask(SIG_BLOCK, &nset, &oset);
 815         if (child_terminated) {
 816                 debug("Received SIGCHLD.");
 817                 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
 818                     (pid < 0 && errno == EINTR))
 819                         if (pid > 0)
 820                                 session_close_by_pid(pid, status);
 821                 child_terminated = 0;
 822         }
 823         sigprocmask(SIG_SETMASK, &oset, NULL);
 824 }
 825
 826 void
 827 server_loop2(Authctxt *authctxt)
 828 {
 829         fd_set *readset = NULL, *writeset = NULL;
 830         int rekeying = 0, max_fd, nalloc = 0;
 831         double start_time, total_time;
 832
 833         debug("Entering interactive session for SSH2.");
 834         start_time = get_current_time();
 835
 836         mysignal(SIGCHLD, sigchld_handler);
 837         child_terminated = 0;
 838         connection_in = packet_get_connection_in();
 839         connection_out = packet_get_connection_out();
 840
 841         if (!use_privsep) {
 842                 signal(SIGTERM, sigterm_handler);
 843                 signal(SIGINT, sigterm_handler);
 844                 signal(SIGQUIT, sigterm_handler);
 845         }
 846
 847         notify_setup();
 848
 849         max_fd = MAX(connection_in, connection_out);
 850         max_fd = MAX(max_fd, notify_pipe[0]);
 851
 852         server_init_dispatch();
 853
 854         for (;;) {
 855                 process_buffered_input_packets();
 856
 857                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
 858
 859                 if (!rekeying && packet_not_very_much_data_to_write())
 860                         channel_output_poll();
 861                 wait_until_can_do_something(&readset, &writeset, &max_fd,
 862                     &nalloc, 0);
 863
 864                 if (received_sigterm) {
 865                         logit("Exiting on signal %d", received_sigterm);
 866                         /* Clean up sessions, utmp, etc. */
 867                         cleanup_exit(255);
 868                 }
 869
 870                 collect_children();
 871                 if (!rekeying) {
 872                         channel_after_select(readset, writeset);
 873                         if (packet_need_rekeying()) {
 874                                 debug("need rekeying");
 875                                 xxx_kex->done = 0;
 876                                 kex_send_kexinit(xxx_kex);
 877                         }
 878                 }
 879                 process_input(readset);
 880                 if (connection_closed)
 881                         break;
 882                 process_output(writeset);
 883         }
 884         collect_children();
 885
 886         if (readset)
 887                 xfree(readset);
 888         if (writeset)
 889                 xfree(writeset);
 890
 891         /* free all channels, no more reads and writes */
 892         channel_free_all();
 893
 894         /* free remaining sessions, e.g. remove wtmp entries */
 895         session_destroy_all(NULL);
 896         total_time = get_current_time() - start_time;
 897         logit("SSH: Server;LType: Throughput;Remote: %s-%d;IN: %lu;OUT: %lu;Duration: %.1f;tPut_in: %.1f;tPut_out: %.1f",
 898               get_remote_ipaddr(), get_remote_port(),
 899               stdin_bytes, fdout_bytes, total_time, stdin_bytes / total_time,
 900               fdout_bytes / total_time);
 901 }
 902
 903 static void
 904 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
 905 {
 906         debug("Got %d/%u for keepalive", type, seq);
 907         /*
 908          * reset timeout, since we got a sane answer from the client.
 909          * even if this was generated by something other than
 910          * the bogus CHANNEL_REQUEST we send for keepalives.
 911          */
 912         keep_alive_timeouts = 0;
 913 }
 914
 915 static void
 916 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
 917 {
 918         char *data;
 919         u_int data_len;
 920
 921         /* Stdin data from the client.  Append it to the buffer. */
 922         /* Ignore any data if the client has closed stdin. */
 923         if (fdin == -1)
 924                 return;
 925         data = packet_get_string(&data_len);
 926         packet_check_eom();
 927         buffer_append(&stdin_buffer, data, data_len);
 928         memset(data, 0, data_len);
 929         xfree(data);
 930 }
 931
 932 static void
 933 server_input_eof(int type, u_int32_t seq, void *ctxt)
 934 {
 935         /*
 936          * Eof from the client.  The stdin descriptor to the
 937          * program will be closed when all buffered data has
 938          * drained.
 939          */
 940         debug("EOF received for stdin.");
 941         packet_check_eom();
 942         stdin_eof = 1;
 943 }
 944
 945 static void
 946 server_input_window_size(int type, u_int32_t seq, void *ctxt)
 947 {
 948         u_int row = packet_get_int();
 949         u_int col = packet_get_int();
 950         u_int xpixel = packet_get_int();
 951         u_int ypixel = packet_get_int();
 952
 953         debug("Window change received.");
 954         packet_check_eom();
 955         if (fdin != -1)
 956                 pty_change_window_size(fdin, row, col, xpixel, ypixel);
 957 }
 958
 959 static Channel *
 960 server_request_direct_tcpip(void)
 961 {
 962         Channel *c;
 963         int sock;
 964         char *target, *originator;
 965         int target_port, originator_port;
 966
 967         target = packet_get_string(NULL);
 968         target_port = packet_get_int();
 969         originator = packet_get_string(NULL);
 970         originator_port = packet_get_int();
 971         packet_check_eom();
 972
 973         debug("server_request_direct_tcpip: originator %s port %d, target %s port %d",
 974             originator, originator_port, target, target_port);
 975
 976         /* XXX check permission */
 977         sock = channel_connect_to(target, target_port);
 978         xfree(target);
 979         xfree(originator);
 980         if (sock < 0)
 981                 return NULL;
 982         if (options.hpn_disabled)
 983         c = channel_new("direct-tcpip", SSH_CHANNEL_CONNECTING,
 984             sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
 985             CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1);
 986         else
 987                 c = channel_new("direct-tcpip", SSH_CHANNEL_CONNECTING,
 988                     sock, sock, -1, options.hpn_buffer_size,
 989                     CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1);
 990         return c;
 991 }
 992
 993 static Channel *
 994 server_request_tun(void)
 995 {
 996         Channel *c = NULL;
 997         int mode, tun;
 998         int sock;
 999
1000         mode = packet_get_int();
1001         switch (mode) {
1002         case SSH_TUNMODE_POINTOPOINT:
1003         case SSH_TUNMODE_ETHERNET:
1004                 break;
1005         default:
1006                 packet_send_debug("Unsupported tunnel device mode.");
1007                 return NULL;
1008         }
1009         if ((options.permit_tun & mode) == 0) {
1010                 packet_send_debug("Server has rejected tunnel device "
1011                     "forwarding");
1012                 return NULL;
1013         }
1014
1015         tun = packet_get_int();
1016         if (forced_tun_device != -1) {
1017                 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1018                         goto done;
1019                 tun = forced_tun_device;
1020         }
1021         sock = tun_open(tun, mode);
1022         if (sock < 0)
1023                 goto done;
1024         if (options.hpn_disabled)
1025         c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1026             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1027         else
1028                 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1029                     options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1030         c->datagram = 1;
1031 #if defined(SSH_TUN_FILTER)
1032         if (mode == SSH_TUNMODE_POINTOPOINT)
1033                 channel_register_filter(c->self, sys_tun_infilter,
1034                     sys_tun_outfilter);
1035 #endif
1036
1037  done:
1038         if (c == NULL)
1039                 packet_send_debug("Failed to open the tunnel device.");
1040         return c;
1041 }
1042
1043 static Channel *
1044 server_request_session(void)
1045 {
1046         Channel *c;
1047
1048         debug("input_session_request");
1049         packet_check_eom();
1050         /*
1051          * A server session has no fd to read or write until a
1052          * CHANNEL_REQUEST for a shell is made, so we set the type to
1053          * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
1054          * CHANNEL_REQUEST messages is registered.
1055          */
1056         c = channel_new("session", SSH_CHANNEL_LARVAL,
1057             -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1058             0, "server-session", 1);
1059         if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled))
1060                 c->dynamic_window = 1;
1061         if (session_open(the_authctxt, c->self) != 1) {
1062                 debug("session open failed, free channel %d", c->self);
1063                 channel_free(c);
1064                 return NULL;
1065         }
1066         channel_register_cleanup(c->self, session_close_by_channel, 0);
1067         return c;
1068 }
1069
1070 static void
1071 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1072 {
1073         Channel *c = NULL;
1074         char *ctype;
1075         int rchan;
1076         u_int rmaxpack, rwindow, len;
1077
1078         ctype = packet_get_string(&len);
1079         rchan = packet_get_int();
1080         rwindow = packet_get_int();
1081         rmaxpack = packet_get_int();
1082
1083         debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1084             ctype, rchan, rwindow, rmaxpack);
1085
1086         if (strcmp(ctype, "session") == 0) {
1087                 c = server_request_session();
1088         } else if (strcmp(ctype, "direct-tcpip") == 0) {
1089                 c = server_request_direct_tcpip();
1090         } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1091                 c = server_request_tun();
1092         }
1093         if (c != NULL) {
1094                 debug("server_input_channel_open: confirm %s", ctype);
1095                 c->remote_id = rchan;
1096                 c->remote_window = rwindow;
1097                 c->remote_maxpacket = rmaxpack;
1098                 if (c->type != SSH_CHANNEL_CONNECTING) {
1099                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1100                         packet_put_int(c->remote_id);
1101                         packet_put_int(c->self);
1102                         packet_put_int(c->local_window);
1103                         packet_put_int(c->local_maxpacket);
1104                         packet_send();
1105                 }
1106         } else {
1107                 debug("server_input_channel_open: failure %s", ctype);
1108                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1109                 packet_put_int(rchan);
1110                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1111                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1112                         packet_put_cstring("open failed");
1113                         packet_put_cstring("");
1114                 }
1115                 packet_send();
1116         }
1117         xfree(ctype);
1118 }
1119
1120 static void
1121 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1122 {
1123         char *rtype;
1124         int want_reply;
1125         int success = 0;
1126
1127         rtype = packet_get_string(NULL);
1128         want_reply = packet_get_char();
1129         debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1130
1131         /* -R style forwarding */
1132         if (strcmp(rtype, "tcpip-forward") == 0) {
1133                 struct passwd *pw;
1134                 char *listen_address;
1135                 u_short listen_port;
1136
1137                 pw = the_authctxt->pw;
1138                 if (pw == NULL || !the_authctxt->valid)
1139                         fatal("server_input_global_request: no/invalid user");
1140                 listen_address = packet_get_string(NULL);
1141                 listen_port = (u_short)packet_get_int();
1142                 debug("server_input_global_request: tcpip-forward listen %s port %d",
1143                     listen_address, listen_port);
1144
1145                 /* check permissions */
1146                 if (!options.allow_tcp_forwarding ||
1147                     no_port_forwarding_flag
1148 #ifndef NO_IPPORT_RESERVED_CONCEPT
1149                     || (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)
1150 #endif
1151                     ) {
1152                         success = 0;
1153                         packet_send_debug("Server has disabled port forwarding.");
1154                 } else {
1155                         /* Start listening on the port */
1156                         success = channel_setup_remote_fwd_listener(
1157                             listen_address, listen_port, options.gateway_ports,
1158                             options.hpn_disabled, options.hpn_buffer_size);
1159                 }
1160                 xfree(listen_address);
1161         } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1162                 char *cancel_address;
1163                 u_short cancel_port;
1164
1165                 cancel_address = packet_get_string(NULL);
1166                 cancel_port = (u_short)packet_get_int();
1167                 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1168                     cancel_address, cancel_port);
1169
1170                 success = channel_cancel_rport_listener(cancel_address,
1171                     cancel_port);
1172                 xfree(cancel_address);
1173         }
1174         if (want_reply) {
1175                 packet_start(success ?
1176                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1177                 packet_send();
1178                 packet_write_wait();
1179         }
1180         xfree(rtype);
1181 }
1182
1183 static void
1184 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1185 {
1186         Channel *c;
1187         int id, reply, success = 0;
1188         char *rtype;
1189
1190         id = packet_get_int();
1191         rtype = packet_get_string(NULL);
1192         reply = packet_get_char();
1193
1194         debug("server_input_channel_req: channel %d request %s reply %d",
1195             id, rtype, reply);
1196
1197         if ((c = channel_lookup(id)) == NULL)
1198                 packet_disconnect("server_input_channel_req: "
1199                     "unknown channel %d", id);
1200         if (c->type == SSH_CHANNEL_LARVAL || c->type == SSH_CHANNEL_OPEN)
1201                 success = session_input_channel_req(c, rtype);
1202         if (reply) {
1203                 packet_start(success ?
1204                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1205                 packet_put_int(c->remote_id);
1206                 packet_send();
1207         }
1208         xfree(rtype);
1209 }
1210
1211 static void
1212 server_init_dispatch_20(void)
1213 {
1214         debug("server_init_dispatch_20");
1215         dispatch_init(&dispatch_protocol_error);
1216         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1217         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1218         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1219         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1220         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1221         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1222         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1223         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1224         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1225         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1226         /* client_alive */
1227         dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1228         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1229         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1230         /* rekeying */
1231         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1232 }
1233 static void
1234 server_init_dispatch_13(void)
1235 {
1236         debug("server_init_dispatch_13");
1237         dispatch_init(NULL);
1238         dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1239         dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1240         dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1241         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1242         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1243         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1244         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1245         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1246         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1247 }
1248 static void
1249 server_init_dispatch_15(void)
1250 {
1251         server_init_dispatch_13();
1252         debug("server_init_dispatch_15");
1253         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1254         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1255 }
1256 static void
1257 server_init_dispatch(void)
1258 {
1259         if (compat20)
1260                 server_init_dispatch_20();
1261         else if (compat13)
1262                 server_init_dispatch_13();
1263         else
1264                 server_init_dispatch_15();
1265 }