]> andersk Git - openssh.git/blobdiff - serverloop.c
- markus@cvs.openbsd.org 2001/06/25 08:25:41
[openssh.git] / serverloop.c
index 50e89aee83497c56c034b08eb984dab162bdc158..2eb8603d1565092638603371521c8875d2dd1b70 100644 (file)
@@ -11,7 +11,7 @@
  * called by a name other than "ssh" or "Secure Shell".
  *
  * SSH2 support by Markus Friedl.
- * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  */
 
 #include "includes.h"
+RCSID("$OpenBSD: serverloop.c,v 1.71 2001/06/25 08:25:39 markus Exp $");
+
 #include "xmalloc.h"
-#include "ssh.h"
 #include "packet.h"
 #include "buffer.h"
+#include "log.h"
 #include "servconf.h"
-#include "pty.h"
+#include "sshpty.h"
 #include "channels.h"
-
 #include "compat.h"
+#include "ssh1.h"
 #include "ssh2.h"
+#include "auth.h"
 #include "session.h"
 #include "dispatch.h"
 #include "auth-options.h"
+#include "serverloop.h"
+#include "misc.h"
+#include "kex.h"
+
+extern ServerOptions options;
+
+/* XXX */
+extern Kex *xxx_kex;
 
 static Buffer stdin_buffer;    /* Buffer for stdin data. */
 static Buffer stdout_buffer;   /* Buffer for stdout data. */
@@ -63,53 +74,31 @@ static long fdout_bytes = 0;        /* Number of stdout bytes read from program. */
 static int stdin_eof = 0;      /* EOF message received from client. */
 static int fdout_eof = 0;      /* EOF encountered reading from fdout. */
 static int fderr_eof = 0;      /* EOF encountered readung from fderr. */
+static int fdin_is_tty = 0;    /* fdin points to a tty. */
 static int connection_in;      /* Connection to client (input). */
 static int connection_out;     /* Connection to client (output). */
-static unsigned int buffer_high;/* "Soft" max buffer size. */
-static int max_fd;             /* Max file descriptor number for select(). */
+static int connection_closed = 0;      /* Connection to client closed. */
+static u_int buffer_high;      /* "Soft" max buffer size. */
 
 /*
  * This SIGCHLD kludge is used to detect when the child exits.  The server
  * will exit after that, as soon as forwarded connections have terminated.
- *
- * After SIGCHLD child_has_selected is set to 1 after the first pass
- * through the wait_until_can_do_something() select(). This ensures
- * that the child's output gets a chance to drain before it is yanked.
  */
 
-static pid_t child_pid;                        /* Pid of the child. */
 static volatile int child_terminated;  /* The child has terminated. */
-static volatile int child_has_selected; /* Child has had chance to drain. */
-static volatile int child_wait_status; /* Status from wait(). */
 
-void   server_init_dispatch(void);
+/* prototypes */
+static void server_init_dispatch(void);
 
-void
-sigchld_handler(int sig)
-{
-       int save_errno = errno;
-       pid_t wait_pid;
+int client_alive_timeouts = 0;
 
-       debug("Received SIGCHLD.");
-       wait_pid = wait((int *) &child_wait_status);
-       if (wait_pid != -1) {
-               if (wait_pid != child_pid)
-                       error("Strange, got SIGCHLD and wait returned pid %d but child is %d",
-                             wait_pid, child_pid);
-               if (WIFEXITED(child_wait_status) ||
-                   WIFSIGNALED(child_wait_status))
-                       child_terminated = 1;
-                       child_has_selected = 0;
-       }
-       signal(SIGCHLD, sigchld_handler);
-       errno = save_errno;
-}
-void
-sigchld_handler2(int sig)
+static void
+sigchld_handler(int sig)
 {
        int save_errno = errno;
        debug("Received SIGCHLD.");
        child_terminated = 1;
+       mysignal(SIGCHLD, sigchld_handler);
        errno = save_errno;
 }
 
@@ -117,8 +106,8 @@ sigchld_handler2(int sig)
  * Make packets from buffered stderr data, and buffer it for sending
  * to the client.
  */
-void
-make_packets_from_stderr_data()
+static void
+make_packets_from_stderr_data(void)
 {
        int len;
 
@@ -146,8 +135,8 @@ make_packets_from_stderr_data()
  * Make packets from buffered stdout data, and buffer it for sending to the
  * client.
  */
-void
-make_packets_from_stdout_data()
+static void
+make_packets_from_stdout_data(void)
 {
        int len;
 
@@ -161,7 +150,7 @@ make_packets_from_stdout_data()
                } else {
                        /* Keep the packets at reasonable size. */
                        if (len > packet_get_maxsize())
-                               len = packet_get_maxsize();     
+                               len = packet_get_maxsize();
                }
                packet_start(SSH_SMSG_STDOUT_DATA);
                packet_put_string(buffer_ptr(&stdout_buffer), len);
@@ -177,24 +166,38 @@ make_packets_from_stdout_data()
  * have data or can accept data.  Optionally, a maximum time can be specified
  * for the duration of the wait (0 = infinite).
  */
-void
-wait_until_can_do_something(fd_set * readset, fd_set * writeset,
-                           unsigned int max_time_milliseconds)
+static void
+wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
+    u_int max_time_milliseconds)
 {
        struct timeval tv, *tvp;
        int ret;
+       int client_alive_scheduled = 0;
+
+       /*
+        * if using client_alive, set the max timeout accordingly, 
+        * and indicate that this particular timeout was for client
+        * alive by setting the client_alive_scheduled flag.
+        *
+        * this could be randomized somewhat to make traffic
+        * analysis more difficult, but we're not doing it yet.  
+        */
+       if (max_time_milliseconds == 0 && options.client_alive_interval) {
+               client_alive_scheduled = 1;
+               max_time_milliseconds = options.client_alive_interval * 1000;
+       } else 
+               client_alive_scheduled = 0;
 
        /* When select fails we restart from here. */
 retry_select:
 
-       /* Initialize select() masks. */
-       FD_ZERO(readset);
-       FD_ZERO(writeset);
+       /* Allocate and update select() masks for channel descriptors. */
+       channel_prepare_select(readsetp, writesetp, maxfdp, 0);
 
        if (compat20) {
                /* wrong: bad condition XXX */
                if (channel_not_very_much_buffered_data())
-                       FD_SET(connection_in, readset);
+                       FD_SET(connection_in, *readsetp);
        } else {
                /*
                 * Read packets from the client unless we have too much
@@ -202,44 +205,38 @@ retry_select:
                 */
                if (buffer_len(&stdin_buffer) < buffer_high &&
                    channel_not_very_much_buffered_data())
-                       FD_SET(connection_in, readset);
+                       FD_SET(connection_in, *readsetp);
                /*
                 * If there is not too much data already buffered going to
                 * the client, try to get some more data from the program.
                 */
                if (packet_not_very_much_data_to_write()) {
                        if (!fdout_eof)
-                               FD_SET(fdout, readset);
+                               FD_SET(fdout, *readsetp);
                        if (!fderr_eof)
-                               FD_SET(fderr, readset);
+                               FD_SET(fderr, *readsetp);
                }
                /*
                 * If we have buffered data, try to write some of that data
                 * to the program.
                 */
                if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
-                       FD_SET(fdin, writeset);
+                       FD_SET(fdin, *writesetp);
        }
-       /* Set masks for channel descriptors. */
-       channel_prepare_select(readset, writeset);
 
        /*
         * If we have buffered packet data going to the client, mark that
         * descriptor.
         */
        if (packet_have_data_to_write())
-               FD_SET(connection_out, writeset);
-
-       /* Update the maximum descriptor number if appropriate. */
-       if (channel_max_fd() > max_fd)
-               max_fd = channel_max_fd();
+               FD_SET(connection_out, *writesetp);
 
        /*
         * If child has terminated and there is enough buffer space to read
         * from it, then read as much as is available and exit.
         */
        if (child_terminated && packet_not_very_much_data_to_write())
-               if (max_time_milliseconds == 0)
+               if (max_time_milliseconds == 0 || client_alive_scheduled)
                        max_time_milliseconds = 100;
 
        if (max_time_milliseconds == 0)
@@ -250,27 +247,48 @@ retry_select:
                tvp = &tv;
        }
        if (tvp!=NULL)
-               debug("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds);
+               debug3("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds);
 
        /* Wait for something to happen, or the timeout to expire. */
-       ret = select(max_fd + 1, readset, writeset, NULL, tvp);
+       ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 
-       if (ret < 0) {
+       if (ret == -1) {
                if (errno != EINTR)
                        error("select: %.100s", strerror(errno));
                else
                        goto retry_select;
        }
-       
-       if (child_terminated)
-               child_has_selected = 1;
+       if (ret == 0 && client_alive_scheduled) {
+               /* timeout, check to see how many we have had */
+               client_alive_timeouts++;
+
+               if (client_alive_timeouts > options.client_alive_count_max ) {
+                       packet_disconnect(
+                               "Timeout, your session not responding.");
+               } else {
+                       /*
+                        * send a bogus channel request with "wantreply" 
+                        * we should get back a failure
+                        */
+                       int id;
+                       
+                       id = channel_find_open();
+                       if (id != -1) {
+                               channel_request_start(id,
+                                 "keepalive@openssh.com", 1);
+                               packet_send();
+                       } else 
+                               packet_disconnect(
+                                       "No open channels after timeout!");
+               }
+       } 
 }
 
 /*
  * Processes input from the client and the program.  Input data is stored
  * in buffers and processed later.
  */
-void
+static void
 process_input(fd_set * readset)
 {
        int len;
@@ -281,6 +299,9 @@ process_input(fd_set * readset)
                len = read(connection_in, buf, sizeof(buf));
                if (len == 0) {
                        verbose("Connection closed by remote host.");
+                       connection_closed = 1;
+                       if (compat20)
+                               return;
                        fatal_cleanup();
                } else if (len < 0) {
                        if (errno != EINTR && errno != EAGAIN) {
@@ -323,9 +344,10 @@ process_input(fd_set * readset)
 /*
  * Sends data from internal buffers to client program stdin.
  */
-void
+static void
 process_output(fd_set * writeset)
 {
+       struct termios tio;
        int len;
 
        /* Write buffered data to program stdin. */
@@ -345,7 +367,17 @@ process_output(fd_set * writeset)
 #endif
                        fdin = -1;
                } else {
-                       /* Successful write.  Consume the data from the buffer. */
+                       /* Successful write. */
+                       if (fdin_is_tty && tcgetattr(fdin, &tio) == 0 &&
+                           !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
+                               /*
+                                * Simulate echo to reduce the impact of
+                                * traffic analysis
+                                */
+                               packet_send_ignore(len);
+                               packet_send();
+                       }
+                       /* Consume the data from the buffer. */
                        buffer_consume(&stdin_buffer, len);
                        /* Update the count of bytes written to the program. */
                        stdin_bytes += len;
@@ -360,8 +392,8 @@ process_output(fd_set * writeset)
  * Wait until all buffered output has been sent to the client.
  * This is used when the program terminates.
  */
-void
-drain_output()
+static void
+drain_output(void)
 {
        /* Send any buffered stdout data to the client. */
        if (buffer_len(&stdout_buffer) > 0) {
@@ -385,10 +417,10 @@ drain_output()
        packet_write_wait();
 }
 
-void
-process_buffered_input_packets()
+static void
+process_buffered_input_packets(void)
 {
-       dispatch_run(DISPATCH_NONBLOCK, NULL, NULL);
+       dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
 }
 
 /*
@@ -401,21 +433,20 @@ process_buffered_input_packets()
 void
 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
 {
-       fd_set readset, writeset;
+       fd_set *readset = NULL, *writeset = NULL;
+       int max_fd;
        int wait_status;        /* Status returned by wait(). */
        pid_t wait_pid;         /* pid returned by wait(). */
        int waiting_termination = 0;    /* Have displayed waiting close message. */
-       unsigned int max_time_milliseconds;
-       unsigned int previous_stdout_buffer_bytes;
-       unsigned int stdout_buffer_bytes;
+       u_int max_time_milliseconds;
+       u_int previous_stdout_buffer_bytes;
+       u_int stdout_buffer_bytes;
        int type;
 
        debug("Entering interactive session.");
 
        /* Initialize the SIGCHLD kludge. */
-       child_pid = pid;
        child_terminated = 0;
-       child_has_selected = 0;
        signal(SIGCHLD, sigchld_handler);
 
        /* Initialize our global variables. */
@@ -430,6 +461,9 @@ server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
        if (fderr != -1)
                set_nonblock(fderr);
 
+       if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
+               fdin_is_tty = 1;
+
        connection_in = packet_get_connection_in();
        connection_out = packet_get_connection_out();
 
@@ -442,15 +476,11 @@ server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
                buffer_high = 64 * 1024;
 
        /* Initialize max_fd to the maximum of the known file descriptors. */
-       max_fd = fdin;
-       if (fdout > max_fd)
-               max_fd = fdout;
-       if (fderr != -1 && fderr > max_fd)
-               max_fd = fderr;
-       if (connection_in > max_fd)
-               max_fd = connection_in;
-       if (connection_out > max_fd)
-               max_fd = connection_out;
+       max_fd = MAX(fdin, fdout);
+       if (fderr != -1)
+               max_fd = MAX(max_fd, fderr);
+       max_fd = MAX(max_fd, connection_in);
+       max_fd = MAX(max_fd, connection_out);
 
        /* Initialize Initialize buffers. */
        buffer_init(&stdin_buffer);
@@ -520,11 +550,8 @@ server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
                 * descriptors, and we have no more data to send to the
                 * client, and there is no pending buffered data.
                 */
-               if (((fdout_eof && fderr_eof) || 
-                   (child_terminated && child_has_selected)) && 
-                   !packet_have_data_to_write() &&
-                   (buffer_len(&stdout_buffer) == 0) && 
-                        (buffer_len(&stderr_buffer) == 0)) {
+               if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
+                   buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
                        if (!channel_still_open())
                                break;
                        if (!waiting_termination) {
@@ -540,18 +567,22 @@ server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
                        }
                }
                /* Sleep in select() until we can do something. */
-               wait_until_can_do_something(&readset, &writeset,
-                                           max_time_milliseconds);
+               wait_until_can_do_something(&readset, &writeset, &max_fd,
+                   max_time_milliseconds);
 
                /* Process any channel events. */
-               channel_after_select(&readset, &writeset);
+               channel_after_select(readset, writeset);
 
                /* Process input from the client and from program stdout/stderr. */
-               process_input(&readset);
+               process_input(readset);
 
                /* Process output to the client and to program stdin. */
-               process_output(&writeset);
+               process_output(writeset);
        }
+       if (readset)
+               xfree(readset);
+       if (writeset)
+               xfree(writeset);
 
        /* Cleanup and termination code. */
 
@@ -579,31 +610,18 @@ server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
                close(fdin);
        fdin = -1;
 
-       /* Stop listening for channels; this removes unix domain sockets. */
-       channel_stop_listening();
-
-       /* Wait for the child to exit.  Get its exit status. */
-       wait_pid = wait(&wait_status);
-       if (wait_pid < 0) {
-               /*
-                * It is possible that the wait was handled by SIGCHLD
-                * handler.  This may result in either: this call
-                * returning with EINTR, or: this call returning ECHILD.
-                */
-               if (child_terminated)
-                       wait_status = child_wait_status;
-               else
-                       packet_disconnect("wait: %.100s", strerror(errno));
-       } else {
-               /* Check if it matches the process we forked. */
-               if (wait_pid != pid)
-                       error("Strange, wait returned pid %d, expected %d",
-                              wait_pid, pid);
-       }
+       channel_free_all();
 
        /* We no longer want our SIGCHLD handler to be called. */
        signal(SIGCHLD, SIG_DFL);
 
+       wait_pid = waitpid(-1, &wait_status, child_terminated ? WNOHANG : 0);
+       if (wait_pid == -1)
+               packet_disconnect("wait: %.100s", strerror(errno));
+       else if (wait_pid != pid)
+               error("Strange, wait returned pid %d, expected %d",
+                   wait_pid, pid);
+
        /* Check if it exited normally. */
        if (WIFEXITED(wait_status)) {
                /* Yes, normal exit.  Get exit status and send it to the client. */
@@ -642,56 +660,72 @@ server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
 void
 server_loop2(void)
 {
-       fd_set readset, writeset;
-       int had_channel = 0;
-       int status;
+       fd_set *readset = NULL, *writeset = NULL;
+       int rekeying = 0, max_fd, status;
        pid_t pid;
 
        debug("Entering interactive session for SSH2.");
 
-       signal(SIGCHLD, sigchld_handler2);
+       mysignal(SIGCHLD, sigchld_handler);
        child_terminated = 0;
        connection_in = packet_get_connection_in();
        connection_out = packet_get_connection_out();
-       max_fd = connection_in;
-       if (connection_out > max_fd)
-               max_fd = connection_out;
+
+       max_fd = MAX(connection_in, connection_out);
+
        server_init_dispatch();
 
        for (;;) {
                process_buffered_input_packets();
-               if (!had_channel && channel_still_open())
-                       had_channel = 1;
-               if (had_channel && !channel_still_open()) {
-                       debug("!channel_still_open.");
-                       break;
-               }
-               if (packet_not_very_much_data_to_write())
+
+               rekeying = (xxx_kex != NULL && !xxx_kex->done);
+
+               if (!rekeying && packet_not_very_much_data_to_write())
                        channel_output_poll();
-               wait_until_can_do_something(&readset, &writeset, 0);
+               wait_until_can_do_something(&readset, &writeset, &max_fd,
+                   rekeying);
                if (child_terminated) {
                        while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
                                session_close_by_pid(pid, status);
                        child_terminated = 0;
-                       signal(SIGCHLD, sigchld_handler2);
-                       if (used_sessions() == 0)
-                               break;
                }
-               channel_after_select(&readset, &writeset);
-               process_input(&readset);
-               process_output(&writeset);
+               if (!rekeying)
+                       channel_after_select(readset, writeset);
+               process_input(readset);
+               if (connection_closed)
+                       break;
+               process_output(writeset);
        }
+       if (readset)
+               xfree(readset);
+       if (writeset)
+               xfree(writeset);
+
+       channel_free_all();
+
        signal(SIGCHLD, SIG_DFL);
        while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
                session_close_by_pid(pid, status);
-       channel_stop_listening();
 }
 
-void
+static void
+server_input_channel_failure(int type, int plen, void *ctxt)
+{
+       debug("Got CHANNEL_FAILURE for keepalive");
+       /* 
+        * reset timeout, since we got a sane answer from the client.
+        * even if this was generated by something other than
+        * the bogus CHANNEL_REQUEST we send for keepalives.
+        */
+       client_alive_timeouts = 0; 
+}
+
+
+static void
 server_input_stdin_data(int type, int plen, void *ctxt)
 {
        char *data;
-       unsigned int data_len;
+       u_int data_len;
 
        /* Stdin data from the client.  Append it to the buffer. */
        /* Ignore any data if the client has closed stdin. */
@@ -704,7 +738,7 @@ server_input_stdin_data(int type, int plen, void *ctxt)
        xfree(data);
 }
 
-void
+static void
 server_input_eof(int type, int plen, void *ctxt)
 {
        /*
@@ -717,7 +751,7 @@ server_input_eof(int type, int plen, void *ctxt)
        stdin_eof = 1;
 }
 
-void
+static void
 server_input_window_size(int type, int plen, void *ctxt)
 {
        int row = packet_get_int();
@@ -731,9 +765,10 @@ server_input_window_size(int type, int plen, void *ctxt)
                pty_change_window_size(fdin, row, col, xpixel, ypixel);
 }
 
-int
-input_direct_tcpip(void)
+static Channel *
+server_request_direct_tcpip(char *ctype)
 {
+       Channel *c;
        int sock;
        char *target, *originator;
        int target_port, originator_port;
@@ -744,32 +779,62 @@ input_direct_tcpip(void)
        originator_port = packet_get_int();
        packet_done();
 
-       debug("open direct-tcpip: from %s port %d to %s port %d",
+       debug("server_request_direct_tcpip: originator %s port %d, target %s port %d",
           originator, originator_port, target, target_port);
 
        /* XXX check permission */
-       if (no_port_forwarding_flag) {
-               xfree(target);
-               xfree(originator);
-               return -1;
-       }
        sock = channel_connect_to(target, target_port);
        xfree(target);
        xfree(originator);
        if (sock < 0)
-               return -1;
-       return channel_new("direct-tcpip", SSH_CHANNEL_OPEN,
+               return NULL;
+       c = channel_new(ctype, SSH_CHANNEL_CONNECTING,
            sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
-           CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"));
+           CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1);
+       if (c == NULL) {
+               error("server_request_direct_tcpip: channel_new failed");
+               close(sock);
+       }
+       return c;
 }
 
-void
+static Channel *
+server_request_session(char *ctype)
+{
+       Channel *c;
+
+       debug("input_session_request");
+       packet_done();
+       /*
+        * A server session has no fd to read or write until a
+        * CHANNEL_REQUEST for a shell is made, so we set the type to
+        * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
+        * CHANNEL_REQUEST messages is registered.
+        */
+       c = channel_new(ctype, SSH_CHANNEL_LARVAL,
+           -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
+           0, xstrdup("server-session"), 1);
+       if (c == NULL) {
+               error("server_request_session: channel_new failed");
+               return NULL;
+       }
+       if (session_open(c->self) != 1) {
+               debug("session open failed, free channel %d", c->self);
+               channel_free(c);
+               return NULL;
+       }
+       channel_register_callback(c->self, SSH2_MSG_CHANNEL_REQUEST,
+           session_input_channel_req, (void *)0);
+       channel_register_cleanup(c->self, session_close_by_channel);
+       return c;
+}
+
+static void
 server_input_channel_open(int type, int plen, void *ctxt)
 {
        Channel *c = NULL;
        char *ctype;
-       int id;
-       unsigned int len;
+       u_int len;
        int rchan;
        int rmaxpack;
        int rwindow;
@@ -783,58 +848,89 @@ server_input_channel_open(int type, int plen, void *ctxt)
            ctype, rchan, rwindow, rmaxpack);
 
        if (strcmp(ctype, "session") == 0) {
-               debug("open session");
-               packet_done();
-               /*
-                * A server session has no fd to read or write
-                * until a CHANNEL_REQUEST for a shell is made,
-                * so we set the type to SSH_CHANNEL_LARVAL.
-                * Additionally, a callback for handling all
-                * CHANNEL_REQUEST messages is registered.
-                */
-               id = channel_new(ctype, SSH_CHANNEL_LARVAL,
-                   -1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT,
-                   0, xstrdup("server-session"));
-               if (session_open(id) == 1) {
-                       channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST,
-                           session_input_channel_req, (void *)0);
-                       channel_register_cleanup(id, session_close_by_channel);
-                       c = channel_lookup(id);
-               } else {
-                       debug("session open failed, free channel %d", id);
-                       channel_free(id);
-               }
+               c = server_request_session(ctype);
        } else if (strcmp(ctype, "direct-tcpip") == 0) {
-               id = input_direct_tcpip();
-               if (id >= 0)
-                       c = channel_lookup(id);
+               c = server_request_direct_tcpip(ctype);
        }
        if (c != NULL) {
-               debug("confirm %s", ctype);
+               debug("server_input_channel_open: confirm %s", ctype);
                c->remote_id = rchan;
                c->remote_window = rwindow;
                c->remote_maxpacket = rmaxpack;
-
-               packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
-               packet_put_int(c->remote_id);
-               packet_put_int(c->self);
-               packet_put_int(c->local_window);
-               packet_put_int(c->local_maxpacket);
-               packet_send();
+               if (c->type != SSH_CHANNEL_CONNECTING) {
+                       packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
+                       packet_put_int(c->remote_id);
+                       packet_put_int(c->self);
+                       packet_put_int(c->local_window);
+                       packet_put_int(c->local_maxpacket);
+                       packet_send();
+               }
        } else {
-               debug("failure %s", ctype);
+               debug("server_input_channel_open: failure %s", ctype);
                packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
                packet_put_int(rchan);
                packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
-               packet_put_cstring("bla bla");
-               packet_put_cstring("");
+               if (!(datafellows & SSH_BUG_OPENFAILURE)) {
+                       packet_put_cstring("open failed");
+                       packet_put_cstring("");
+               }
                packet_send();
        }
        xfree(ctype);
 }
 
-void
-server_init_dispatch_20()
+static void
+server_input_global_request(int type, int plen, void *ctxt)
+{
+       char *rtype;
+       int want_reply;
+       int success = 0;
+
+       rtype = packet_get_string(NULL);
+       want_reply = packet_get_char();
+       debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
+
+       /* -R style forwarding */
+       if (strcmp(rtype, "tcpip-forward") == 0) {
+               struct passwd *pw;
+               char *listen_address;
+               u_short listen_port;
+
+               pw = auth_get_user();
+               if (pw == NULL)
+                       fatal("server_input_global_request: no user");
+               listen_address = packet_get_string(NULL); /* XXX currently ignored */
+               listen_port = (u_short)packet_get_int();
+               debug("server_input_global_request: tcpip-forward listen %s port %d",
+                   listen_address, listen_port);
+
+               /* check permissions */
+               if (!options.allow_tcp_forwarding ||
+                   no_port_forwarding_flag ||
+                   (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)) {
+                       success = 0;
+                       packet_send_debug("Server has disabled port forwarding.");
+               } else {
+                       /* Start listening on the port */
+                       success = channel_request_forwarding(
+                           listen_address, listen_port,
+                           /*unspec host_to_connect*/ "<unspec host>",
+                           /*unspec port_to_connect*/ 0,
+                           options.gateway_ports, /*remote*/ 1);
+               }
+               xfree(listen_address);
+       }
+       if (want_reply) {
+               packet_start(success ?
+                   SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
+               packet_send();
+               packet_write_wait();
+       }
+       xfree(rtype);
+}
+
+static void
+server_init_dispatch_20(void)
 {
        debug("server_init_dispatch_20");
        dispatch_init(&dispatch_protocol_error);
@@ -847,9 +943,14 @@ server_init_dispatch_20()
        dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
        dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
        dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
+       dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
+       /* client_alive */
+       dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_channel_failure);
+       /* rekeying */
+       dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
 }
-void
-server_init_dispatch_13()
+static void
+server_init_dispatch_13(void)
 {
        debug("server_init_dispatch_13");
        dispatch_init(NULL);
@@ -863,16 +964,16 @@ server_init_dispatch_13()
        dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
        dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
 }
-void
-server_init_dispatch_15()
+static void
+server_init_dispatch_15(void)
 {
        server_init_dispatch_13();
        debug("server_init_dispatch_15");
        dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
        dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
 }
-void
-server_init_dispatch()
+static void
+server_init_dispatch(void)
 {
        if (compat20)
                server_init_dispatch_20();
@@ -881,3 +982,4 @@ server_init_dispatch()
        else
                server_init_dispatch_15();
 }
+
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