1 files changed, 346 insertions, 409 deletions

diff --git a/clientloop.c b/clientloop.c
index b57fda042..f10fab769 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: clientloop.c,v 1.181 2007/08/15 08:14:46 markus Exp $ */
+/* $OpenBSD: clientloop.c,v 1.201 2008/07/16 11:51:14 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -86,6 +86,7 @@
 #include <pwd.h>
 #include <unistd.h>
 
+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "ssh.h"
 #include "ssh1.h"
@@ -120,7 +121,7 @@ extern int stdin_null_flag;
 extern int no_shell_flag;
 
 /* Control socket */
-extern int control_fd;
+extern int muxserver_sock;
 
 /*
  * Name of the host we are connecting to.  This is the name given on the
@@ -143,36 +144,46 @@ static int in_non_blocking_mode = 0;
 
 /* Common data for the client loop code. */
 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
-static int escape_char;         /* Escape character. */
-static int escape_pending;      /* Last character was the escape character */
+static int escape_char1;        /* Escape character. (proto1 only) */
+static int escape_pending1;     /* Last character was an escape (proto1 only) */
 static int last_was_cr;         /* Last character was a newline. */
-static int exit_status;         /* Used to store the exit status of the command. */
-static int stdin_eof;           /* EOF has been encountered on standard error. */
+static int exit_status;         /* Used to store the command exit status. */
+static int stdin_eof;           /* EOF has been encountered on stderr. */
 static Buffer stdin_buffer;     /* Buffer for stdin data. */
 static Buffer stdout_buffer;    /* Buffer for stdout data. */
 static Buffer stderr_buffer;    /* Buffer for stderr data. */
-static u_long stdin_bytes, stdout_bytes, stderr_bytes;
 static u_int buffer_high;/* Soft max buffer size. */
 static int connection_in;       /* Connection to server (input). */
 static int connection_out;      /* Connection to server (output). */
 static int need_rekeying;       /* Set to non-zero if rekeying is requested. */
 static int session_closed = 0;  /* In SSH2: login session closed. */
-static int server_alive_timeouts = 0;
 
 static void client_init_dispatch(void);
 int     session_ident = -1;
 
-struct confirm_ctx {
-        int want_tty;
-        int want_subsys;
-        int want_x_fwd;
-        int want_agent_fwd;
-        Buffer cmd;
-        char *term;
-        struct termios tio;
-        char **env;
+/* Track escape per proto2 channel */
+struct escape_filter_ctx {
+        int escape_pending;
+        int escape_char;
 };
 
+/* Context for channel confirmation replies */
+struct channel_reply_ctx {
+        const char *request_type;
+        int id, do_close;
+};
+
+/* Global request success/failure callbacks */
+struct global_confirm {
+        TAILQ_ENTRY(global_confirm) entry;
+        global_confirm_cb *cb;
+        void *ctx;
+        int ref_count;
+};
+TAILQ_HEAD(global_confirms, global_confirm);
+static struct global_confirms global_confirms =
+    TAILQ_HEAD_INITIALIZER(global_confirms);
+
 /*XXX*/
 extern Kex *xxx_kex;
 
@@ -380,7 +391,10 @@ client_check_initial_eof_on_stdin(void)
                 /* Check for immediate EOF on stdin. */
                 len = read(fileno(stdin), buf, 1);
                 if (len == 0) {
-                        /* EOF.  Record that we have seen it and send EOF to server. */
+                        /*
+                         * EOF.  Record that we have seen it and send
+                         * EOF to server.
+                         */
                         debug("Sending eof.");
                         stdin_eof = 1;
                         packet_start(SSH_CMSG_EOF);
@@ -391,8 +405,8 @@ client_check_initial_eof_on_stdin(void)
                          * and also process it as an escape character if
                          * appropriate.
                          */
-                        if ((u_char) buf[0] == escape_char)
-                                escape_pending = 1;
+                        if ((u_char) buf[0] == escape_char1)
+                                escape_pending1 = 1;
                         else
                                 buffer_append(&stdin_buffer, buf, 1);
                 }
@@ -422,7 +436,6 @@ client_make_packets_from_stdin_data(void)
                 packet_put_string(buffer_ptr(&stdin_buffer), len);
                 packet_send();
                 buffer_consume(&stdin_buffer, len);
-                stdin_bytes += len;
                 /* If we have a pending EOF, send it now. */
                 if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
                         packet_start(SSH_CMSG_EOF);
@@ -467,14 +480,25 @@ client_check_window_change(void)
 static void
 client_global_request_reply(int type, u_int32_t seq, void *ctxt)
 {
-        server_alive_timeouts = 0;
-        client_global_request_reply_fwd(type, seq, ctxt);
+        struct global_confirm *gc;
+
+        if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
+                return;
+        if (gc->cb != NULL)
+                gc->cb(type, seq, gc->ctx);
+        if (--gc->ref_count <= 0) {
+                TAILQ_REMOVE(&global_confirms, gc, entry);
+                bzero(gc, sizeof(*gc));
+                xfree(gc);
+        }
+
+        keep_alive_timeouts = 0;
 }
 
 static void
 server_alive_check(void)
 {
-        if (++server_alive_timeouts > options.server_alive_count_max) {
+        if (++keep_alive_timeouts > options.server_alive_count_max) {
                 logit("Timeout, server not responding.");
                 cleanup_exit(255);
         }
@@ -482,6 +506,8 @@ server_alive_check(void)
         packet_put_cstring("keepalive@openssh.com");
         packet_put_char(1);     /* boolean: want reply */
         packet_send();
+        /* Insert an empty placeholder to maintain ordering */
+        client_register_global_confirm(NULL, NULL);
 }
 
 /*
@@ -533,8 +559,8 @@ client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
         if (packet_have_data_to_write())
                 FD_SET(connection_out, *writesetp);
 
-        if (control_fd != -1)
-                FD_SET(control_fd, *readsetp);
+        if (muxserver_sock != -1)
+                FD_SET(muxserver_sock, *readsetp);
 
         /*
          * Wait for something to happen.  This will suspend the process until
@@ -576,9 +602,11 @@ client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
 {
         /* Flush stdout and stderr buffers. */
         if (buffer_len(bout) > 0)
-                atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
+                atomicio(vwrite, fileno(stdout), buffer_ptr(bout),
+                    buffer_len(bout));
         if (buffer_len(berr) > 0)
-                atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr));
+                atomicio(vwrite, fileno(stderr), buffer_ptr(berr),
+                    buffer_len(berr));
 
         leave_raw_mode();
 
@@ -618,9 +646,13 @@ client_process_net_input(fd_set *readset)
                 /* Read as much as possible. */
                 len = read(connection_in, buf, sizeof(buf));
                 if (len == 0) {
-                        /* Received EOF.  The remote host has closed the connection. */
-                        snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
-                                 host);
+                        /*
+                         * Received EOF.  The remote host has closed the
+                         * connection.
+                         */
+                        snprintf(buf, sizeof buf,
+                            "Connection to %.300s closed by remote host.\r\n",
+                            host);
                         buffer_append(&stderr_buffer, buf, strlen(buf));
                         quit_pending = 1;
                         return;
@@ -629,13 +661,18 @@ client_process_net_input(fd_set *readset)
                  * There is a kernel bug on Solaris that causes select to
                  * sometimes wake up even though there is no data available.
                  */
-                if (len < 0 && (errno == EAGAIN || errno == EINTR))
+                if (len < 0 &&
+                    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
                         len = 0;
 
                 if (len < 0) {
-                        /* An error has encountered.  Perhaps there is a network problem. */
-                        snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
-                                 host, strerror(errno));
+                        /*
+                         * An error has encountered.  Perhaps there is a
+                         * network problem.
+                         */
+                        snprintf(buf, sizeof buf,
+                            "Read from remote host %.300s: %.100s\r\n",
+                            host, strerror(errno));
                         buffer_append(&stderr_buffer, buf, strlen(buf));
                         quit_pending = 1;
                         return;
@@ -645,289 +682,81 @@ client_process_net_input(fd_set *readset)
 }
 
 static void
-client_subsystem_reply(int type, u_int32_t seq, void *ctxt)
+client_status_confirm(int type, Channel *c, void *ctx)
 {
-        int id;
-        Channel *c;
-
-        id = packet_get_int();
-        packet_check_eom();
-
-        if ((c = channel_lookup(id)) == NULL) {
-                error("%s: no channel for id %d", __func__, id);
-                return;
-        }
-
-        if (type == SSH2_MSG_CHANNEL_SUCCESS)
-                debug2("Request suceeded on channel %d", id);
-        else if (type == SSH2_MSG_CHANNEL_FAILURE) {
-                error("Request failed on channel %d", id);
-                channel_free(c);
+        struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx;
+        char errmsg[256];
+        int tochan;
+
+        /* XXX supress on mux _client_ quietmode */
+        tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
+            c->ctl_fd != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
+
+        if (type == SSH2_MSG_CHANNEL_SUCCESS) {
+                debug2("%s request accepted on channel %d",
+                    cr->request_type, c->self);
+        } else if (type == SSH2_MSG_CHANNEL_FAILURE) {
+                if (tochan) {
+                        snprintf(errmsg, sizeof(errmsg),
+                            "%s request failed\r\n", cr->request_type);
+                } else {
+                        snprintf(errmsg, sizeof(errmsg),
+                            "%s request failed on channel %d",
+                            cr->request_type, c->self);
+                }
+                /* If error occurred on primary session channel, then exit */
+                if (cr->do_close && c->self == session_ident)
+                        fatal("%s", errmsg);
+                /* If error occurred on mux client, append to their stderr */
+                if (tochan)
+                        buffer_append(&c->extended, errmsg, strlen(errmsg));
+                else
+                        error("%s", errmsg);
+                if (cr->do_close) {
+                        chan_read_failed(c);
+                        chan_write_failed(c);
+                }
         }
+        xfree(cr);
 }
 
 static void
-client_extra_session2_setup(int id, void *arg)
+client_abandon_status_confirm(Channel *c, void *ctx)
 {
-        struct confirm_ctx *cctx = arg;
-        const char *display;
-        Channel *c;
-        int i;
-
-        if (cctx == NULL)
-                fatal("%s: cctx == NULL", __func__);
-        if ((c = channel_lookup(id)) == NULL)
-                fatal("%s: no channel for id %d", __func__, id);
-
-        display = getenv("DISPLAY");
-        if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
-                char *proto, *data;
-                /* Get reasonable local authentication information. */
-                client_x11_get_proto(display, options.xauth_location,
-                    options.forward_x11_trusted, &proto, &data);
-                /* Request forwarding with authentication spoofing. */
-                debug("Requesting X11 forwarding with authentication spoofing.");
-                x11_request_forwarding_with_spoofing(id, display, proto, data);
-                /* XXX wait for reply */
-        }
-
-        if (cctx->want_agent_fwd && options.forward_agent) {
-                debug("Requesting authentication agent forwarding.");
-                channel_request_start(id, "auth-agent-req@openssh.com", 0);
-                packet_send();
-        }
-
-        client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
-            cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env,
-            client_subsystem_reply);
-
-        c->confirm_ctx = NULL;
-        buffer_free(&cctx->cmd);
-        xfree(cctx->term);
-        if (cctx->env != NULL) {
-                for (i = 0; cctx->env[i] != NULL; i++)
-                        xfree(cctx->env[i]);
-                xfree(cctx->env);
-        }
-        xfree(cctx);
+        xfree(ctx);
 }
 
 static void
-client_process_control(fd_set *readset)
+client_expect_confirm(int id, const char *request, int do_close)
 {
-        Buffer m;
-        Channel *c;
-        int client_fd, new_fd[3], ver, allowed, window, packetmax;
-        socklen_t addrlen;
-        struct sockaddr_storage addr;
-        struct confirm_ctx *cctx;
-        char *cmd;
-        u_int i, len, env_len, command, flags;
-        uid_t euid;
-        gid_t egid;
-
-        /*
-         * Accept connection on control socket
-         */
-        if (control_fd == -1 || !FD_ISSET(control_fd, readset))
-                return;
-
-        memset(&addr, 0, sizeof(addr));
-        addrlen = sizeof(addr);
-        if ((client_fd = accept(control_fd,
-            (struct sockaddr*)&addr, &addrlen)) == -1) {
-                error("%s accept: %s", __func__, strerror(errno));
-                return;
-        }
-
-        if (getpeereid(client_fd, &euid, &egid) < 0) {
-                error("%s getpeereid failed: %s", __func__, strerror(errno));
-                close(client_fd);
-                return;
-        }
-        if ((euid != 0) && (getuid() != euid)) {
-                error("control mode uid mismatch: peer euid %u != uid %u",
-                    (u_int) euid, (u_int) getuid());
-                close(client_fd);
-                return;
-        }
-
-        unset_nonblock(client_fd);
-
-        /* Read command */
-        buffer_init(&m);
-        if (ssh_msg_recv(client_fd, &m) == -1) {
-                error("%s: client msg_recv failed", __func__);
-                close(client_fd);
-                buffer_free(&m);
-                return;
-        }
-        if ((ver = buffer_get_char(&m)) != SSHMUX_VER) {
-                error("%s: wrong client version %d", __func__, ver);
-                buffer_free(&m);
-                close(client_fd);
-                return;
-        }
-
-        allowed = 1;
-        command = buffer_get_int(&m);
-        flags = buffer_get_int(&m);
-
-        buffer_clear(&m);
-
-        switch (command) {
-        case SSHMUX_COMMAND_OPEN:
-                if (options.control_master == SSHCTL_MASTER_ASK ||
-                    options.control_master == SSHCTL_MASTER_AUTO_ASK)
-                        allowed = ask_permission("Allow shared connection "
-                            "to %s? ", host);
-                /* continue below */
-                break;
-        case SSHMUX_COMMAND_TERMINATE:
-                if (options.control_master == SSHCTL_MASTER_ASK ||
-                    options.control_master == SSHCTL_MASTER_AUTO_ASK)
-                        allowed = ask_permission("Terminate shared connection "
-                            "to %s? ", host);
-                if (allowed)
-                        quit_pending = 1;
-                /* FALLTHROUGH */
-        case SSHMUX_COMMAND_ALIVE_CHECK:
-                /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */
-                buffer_clear(&m);
-                buffer_put_int(&m, allowed);
-                buffer_put_int(&m, getpid());
-                if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
-                        error("%s: client msg_send failed", __func__);
-                        close(client_fd);
-                        buffer_free(&m);
-                        return;
-                }
-                buffer_free(&m);
-                close(client_fd);
-                return;
-        default:
-                error("Unsupported command %d", command);
-                buffer_free(&m);
-                close(client_fd);
-                return;
-        }
-
-        /* Reply for SSHMUX_COMMAND_OPEN */
-        buffer_clear(&m);
-        buffer_put_int(&m, allowed);
-        buffer_put_int(&m, getpid());
-        if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
-                error("%s: client msg_send failed", __func__);
-                close(client_fd);
-                buffer_free(&m);
-                return;
-        }
-
-        if (!allowed) {
-                error("Refused control connection");
-                close(client_fd);
-                buffer_free(&m);
-                return;
-        }
+        struct channel_reply_ctx *cr = xmalloc(sizeof(*cr));
 
-        buffer_clear(&m);
-        if (ssh_msg_recv(client_fd, &m) == -1) {
-                error("%s: client msg_recv failed", __func__);
-                close(client_fd);
-                buffer_free(&m);
-                return;
-        }
-        if ((ver = buffer_get_char(&m)) != SSHMUX_VER) {
-                error("%s: wrong client version %d", __func__, ver);
-                buffer_free(&m);
-                close(client_fd);
-                return;
-        }
+        cr->request_type = request;
+        cr->do_close = do_close;
 
-        cctx = xcalloc(1, sizeof(*cctx));
-        cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0;
-        cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0;
-        cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0;
-        cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0;
-        cctx->term = buffer_get_string(&m, &len);
-
-        cmd = buffer_get_string(&m, &len);
-        buffer_init(&cctx->cmd);
-        buffer_append(&cctx->cmd, cmd, strlen(cmd));
-
-        env_len = buffer_get_int(&m);
-        env_len = MIN(env_len, 4096);
-        debug3("%s: receiving %d env vars", __func__, env_len);
-        if (env_len != 0) {
-                cctx->env = xcalloc(env_len + 1, sizeof(*cctx->env));
-                for (i = 0; i < env_len; i++)
-                        cctx->env[i] = buffer_get_string(&m, &len);
-                cctx->env[i] = NULL;
-        }
+        channel_register_status_confirm(id, client_status_confirm,
+            client_abandon_status_confirm, cr);
+}
 
-        debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
-            cctx->want_tty, cctx->want_subsys, cmd);
-        xfree(cmd);
-
-        /* Gather fds from client */
-        new_fd[0] = mm_receive_fd(client_fd);
-        new_fd[1] = mm_receive_fd(client_fd);
-        new_fd[2] = mm_receive_fd(client_fd);
-
-        debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
-            new_fd[0], new_fd[1], new_fd[2]);
-
-        /* Try to pick up ttymodes from client before it goes raw */
-        if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
-                error("%s: tcgetattr: %s", __func__, strerror(errno));
-
-        /* This roundtrip is just for synchronisation of ttymodes */
-        buffer_clear(&m);
-        if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
-                error("%s: client msg_send failed", __func__);
-                close(client_fd);
-                close(new_fd[0]);
-                close(new_fd[1]);
-                close(new_fd[2]);
-                buffer_free(&m);
-                xfree(cctx->term);
-                if (env_len != 0) {
-                        for (i = 0; i < env_len; i++)
-                                xfree(cctx->env[i]);
-                        xfree(cctx->env);
-                }
+void
+client_register_global_confirm(global_confirm_cb *cb, void *ctx)
+{
+        struct global_confirm *gc, *last_gc;
+
+        /* Coalesce identical callbacks */
+        last_gc = TAILQ_LAST(&global_confirms, global_confirms);
+        if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) {
+                if (++last_gc->ref_count >= INT_MAX)
+                        fatal("%s: last_gc->ref_count = %d",
+                            __func__, last_gc->ref_count);
                 return;
         }
-        buffer_free(&m);
-
-        /* enable nonblocking unless tty */
-        if (!isatty(new_fd[0]))
-                set_nonblock(new_fd[0]);
-        if (!isatty(new_fd[1]))
-                set_nonblock(new_fd[1]);
-        if (!isatty(new_fd[2]))
-                set_nonblock(new_fd[2]);
-
-        set_nonblock(client_fd);
-
-        window = CHAN_SES_WINDOW_DEFAULT;
-        packetmax = CHAN_SES_PACKET_DEFAULT;
-        if (cctx->want_tty) {
-                window >>= 1;
-                packetmax >>= 1;
-        }
-        
-        c = channel_new("session", SSH_CHANNEL_OPENING,
-            new_fd[0], new_fd[1], new_fd[2], window, packetmax,
-            CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
 
-        /* XXX */
-        c->ctl_fd = client_fd;
-
-        debug3("%s: channel_new: %d", __func__, c->self);
-
-        channel_send_open(c->self);
-        channel_register_confirm(c->self, client_extra_session2_setup, cctx);
+        gc = xmalloc(sizeof(*gc));
+        gc->cb = cb;
+        gc->ctx = ctx;
+        gc->ref_count = 1;
+        TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
 }
 
 static void
@@ -940,6 +769,9 @@ process_cmdline(void)
         u_short cancel_port;
         Forward fwd;
 
+        bzero(&fwd, sizeof(fwd));
+        fwd.listen_host = fwd.connect_host = NULL;
+
         leave_raw_mode();
         handler = signal(SIGINT, SIG_IGN);
         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
@@ -1039,11 +871,18 @@ out:
         enter_raw_mode();
         if (cmd)
                 xfree(cmd);
+        if (fwd.listen_host != NULL)
+                xfree(fwd.listen_host);
+        if (fwd.connect_host != NULL)
+                xfree(fwd.connect_host);
 }
 
-/* process the characters one by one */
+/* 
+ * Process the characters one by one, call with c==NULL for proto1 case.
+ */
 static int
-process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
+process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
+    char *buf, int len)
 {
         char string[1024];
         pid_t pid;
@@ -1051,7 +890,20 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
         u_int i;
         u_char ch;
         char *s;
+        int *escape_pendingp, escape_char;
+        struct escape_filter_ctx *efc;
 
+        if (c == NULL) {
+                escape_pendingp = &escape_pending1;
+                escape_char = escape_char1;
+        } else {
+                if (c->filter_ctx == NULL)
+                        return 0;
+                efc = (struct escape_filter_ctx *)c->filter_ctx;
+                escape_pendingp = &efc->escape_pending;
+                escape_char = efc->escape_char;
+        }
+        
         if (len <= 0)
                 return (0);
 
@@ -1059,25 +911,42 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
                 /* Get one character at a time. */
                 ch = buf[i];
 
-                if (escape_pending) {
+                if (*escape_pendingp) {
                         /* We have previously seen an escape character. */
                         /* Clear the flag now. */
-                        escape_pending = 0;
+                        *escape_pendingp = 0;
 
                         /* Process the escaped character. */
                         switch (ch) {
                         case '.':
                                 /* Terminate the connection. */
-                                snprintf(string, sizeof string, "%c.\r\n", escape_char);
+                                snprintf(string, sizeof string, "%c.\r\n",
+                                    escape_char);
                                 buffer_append(berr, string, strlen(string));
 
-                                quit_pending = 1;
+                                if (c && c->ctl_fd != -1) {
+                                        chan_read_failed(c);
+                                        chan_write_failed(c);
+                                        return 0;
+                                } else
+                                        quit_pending = 1;
                                 return -1;
 
                         case 'Z' - 64:
-                                /* Suspend the program. */
-                                /* Print a message to that effect to the user. */
-                                snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
+                                /* XXX support this for mux clients */
+                                if (c && c->ctl_fd != -1) {
+ noescape:
+                                        snprintf(string, sizeof string,
+                                            "%c%c escape not available to "
+                                            "multiplexed sessions\r\n",
+                                            escape_char, ch);
+                                        buffer_append(berr, string,
+                                            strlen(string));
+                                        continue;
+                                }
+                                /* Suspend the program. Inform the user */
+                                snprintf(string, sizeof string,
+                                    "%c^Z [suspend ssh]\r\n", escape_char);
                                 buffer_append(berr, string, strlen(string));
 
                                 /* Restore terminal modes and suspend. */
@@ -1102,16 +971,20 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
                         case 'R':
                                 if (compat20) {
                                         if (datafellows & SSH_BUG_NOREKEY)
-                                                logit("Server does not support re-keying");
+                                                logit("Server does not "
+                                                    "support re-keying");
                                         else
                                                 need_rekeying = 1;
                                 }
                                 continue;
 
                         case '&':
+                                if (c && c->ctl_fd != -1)
+                                        goto noescape;
                                 /*
-                                 * Detach the program (continue to serve connections,
-                                 * but put in background and no more new connections).
+                                 * Detach the program (continue to serve
+                                 * connections, but put in background and no
+                                 * more new connections).
                                  */
                                 /* Restore tty modes. */
                                 leave_raw_mode();
@@ -1140,9 +1013,9 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
                                         return -1;
                                 } else if (!stdin_eof) {
                                         /*
-                                         * Sending SSH_CMSG_EOF alone does not always appear
-                                         * to be enough.  So we try to send an EOF character
-                                         * first.
+                                         * Sending SSH_CMSG_EOF alone does not
+                                         * always appear to be enough.  So we
+                                         * try to send an EOF character first.
                                          */
                                         packet_start(SSH_CMSG_STDIN_DATA);
                                         packet_put_string("\004", 1);
@@ -1157,27 +1030,50 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
                                 continue;
 
                         case '?':
-                                snprintf(string, sizeof string,
+                                if (c && c->ctl_fd != -1) {
+                                        snprintf(string, sizeof string,
 "%c?\r\n\
 Supported escape sequences:\r\n\
-%c.  - terminate connection\r\n\
-%cB  - send a BREAK to the remote system\r\n\
-%cC  - open a command line\r\n\
-%cR  - Request rekey (SSH protocol 2 only)\r\n\
-%c^Z - suspend ssh\r\n\
-%c#  - list forwarded connections\r\n\
-%c&  - background ssh (when waiting for connections to terminate)\r\n\
-%c?  - this message\r\n\
-%c%c  - send the escape character by typing it twice\r\n\
+  %c.  - terminate session\r\n\
+  %cB  - send a BREAK to the remote system\r\n\
+  %cC  - open a command line\r\n\
+  %cR  - Request rekey (SSH protocol 2 only)\r\n\
+  %c#  - list forwarded connections\r\n\
+  %c?  - this message\r\n\
+  %c%c  - send the escape character by typing it twice\r\n\
 (Note that escapes are only recognized immediately after newline.)\r\n",
-                                    escape_char, escape_char, escape_char, escape_char,
-                                    escape_char, escape_char, escape_char, escape_char,
-                                    escape_char, escape_char, escape_char);
+                                            escape_char, escape_char,
+                                            escape_char, escape_char,
+                                            escape_char, escape_char,
+                                            escape_char, escape_char,
+                                            escape_char);
+                                } else {
+                                        snprintf(string, sizeof string,
+"%c?\r\n\
+Supported escape sequences:\r\n\
+  %c.  - terminate connection (and any multiplexed sessions)\r\n\
+  %cB  - send a BREAK to the remote system\r\n\
+  %cC  - open a command line\r\n\
+  %cR  - Request rekey (SSH protocol 2 only)\r\n\
+  %c^Z - suspend ssh\r\n\
+  %c#  - list forwarded connections\r\n\
+  %c&  - background ssh (when waiting for connections to terminate)\r\n\
+  %c?  - this message\r\n\
+  %c%c  - send the escape character by typing it twice\r\n\
+(Note that escapes are only recognized immediately after newline.)\r\n",
+                                            escape_char, escape_char,
+                                            escape_char, escape_char,
+                                            escape_char, escape_char,
+                                            escape_char, escape_char,
+                                            escape_char, escape_char,
+                                            escape_char);
+                                }
                                 buffer_append(berr, string, strlen(string));
                                 continue;
 
                         case '#':
-                                snprintf(string, sizeof string, "%c#\r\n", escape_char);
+                                snprintf(string, sizeof string, "%c#\r\n",
+                                    escape_char);
                                 buffer_append(berr, string, strlen(string));
                                 s = channel_open_message();
                                 buffer_append(berr, s, strlen(s));
@@ -1198,12 +1094,15 @@ Supported escape sequences:\r\n\
                         }
                 } else {
                         /*
-                         * The previous character was not an escape char. Check if this
-                         * is an escape.
+                         * The previous character was not an escape char.
+                         * Check if this is an escape.
                          */
                         if (last_was_cr && ch == escape_char) {
-                                /* It is. Set the flag and continue to next character. */
-                                escape_pending = 1;
+                                /*
+                                 * It is. Set the flag and continue to
+                                 * next character.
+                                 */
+                                *escape_pendingp = 1;
                                 continue;
                         }
                 }
@@ -1229,7 +1128,8 @@ client_process_input(fd_set *readset)
         if (FD_ISSET(fileno(stdin), readset)) {
                 /* Read as much as possible. */
                 len = read(fileno(stdin), buf, sizeof(buf));
-                if (len < 0 && (errno == EAGAIN || errno == EINTR))
+                if (len < 0 &&
+                    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
                         return;         /* we'll try again later */
                 if (len <= 0) {
                         /*
@@ -1238,7 +1138,8 @@ client_process_input(fd_set *readset)
                          * if it was an error condition.
                          */
                         if (len < 0) {
-                                snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
+                                snprintf(buf, sizeof buf, "read: %.100s\r\n",
+                                    strerror(errno));
                                 buffer_append(&stderr_buffer, buf, strlen(buf));
                         }
                         /* Mark that we have seen EOF. */
@@ -1254,7 +1155,7 @@ client_process_input(fd_set *readset)
                                 packet_start(SSH_CMSG_EOF);
                                 packet_send();
                         }
-                } else if (escape_char == SSH_ESCAPECHAR_NONE) {
+                } else if (escape_char1 == SSH_ESCAPECHAR_NONE) {
                         /*
                          * Normal successful read, and no escape character.
                          * Just append the data to buffer.
@@ -1262,11 +1163,12 @@ client_process_input(fd_set *readset)
                         buffer_append(&stdin_buffer, buf, len);
                 } else {
                         /*
-                         * Normal, successful read.  But we have an escape character
-                         * and have to process the characters one by one.
+                         * Normal, successful read.  But we have an escape
+                         * character and have to process the characters one
+                         * by one.
                          */
-                        if (process_escapes(&stdin_buffer, &stdout_buffer,
-                            &stderr_buffer, buf, len) == -1)
+                        if (process_escapes(NULL, &stdin_buffer,
+                            &stdout_buffer, &stderr_buffer, buf, len) == -1)
                                 return;
                 }
         }
@@ -1284,14 +1186,16 @@ client_process_output(fd_set *writeset)
                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
                     buffer_len(&stdout_buffer));
                 if (len <= 0) {
-                        if (errno == EINTR || errno == EAGAIN)
+                        if (errno == EINTR || errno == EAGAIN ||
+                            errno == EWOULDBLOCK)
                                 len = 0;
                         else {
                                 /*
                                  * An error or EOF was encountered.  Put an
                                  * error message to stderr buffer.
                                  */
-                                snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
+                                snprintf(buf, sizeof buf,
+                                    "write stdout: %.50s\r\n", strerror(errno));
                                 buffer_append(&stderr_buffer, buf, strlen(buf));
                                 quit_pending = 1;
                                 return;
@@ -1299,7 +1203,6 @@ client_process_output(fd_set *writeset)
                 }
                 /* Consume printed data from the buffer. */
                 buffer_consume(&stdout_buffer, len);
-                stdout_bytes += len;
         }
         /* Write buffered output to stderr. */
         if (FD_ISSET(fileno(stderr), writeset)) {
@@ -1307,17 +1210,20 @@ client_process_output(fd_set *writeset)
                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
                     buffer_len(&stderr_buffer));
                 if (len <= 0) {
-                        if (errno == EINTR || errno == EAGAIN)
+                        if (errno == EINTR || errno == EAGAIN ||
+                            errno == EWOULDBLOCK)
                                 len = 0;
                         else {
-                                /* EOF or error, but can't even print error message. */
+                                /*
+                                 * EOF or error, but can't even print
+                                 * error message.
+                                 */
                                 quit_pending = 1;
                                 return;
                         }
                 }
                 /* Consume printed characters from the buffer. */
                 buffer_consume(&stderr_buffer, len);
-                stderr_bytes += len;
         }
 }
 
@@ -1336,16 +1242,39 @@ client_process_output(fd_set *writeset)
 static void
 client_process_buffered_input_packets(void)
 {
-        dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL);
+        dispatch_run(DISPATCH_NONBLOCK, &quit_pending,
+            compat20 ? xxx_kex : NULL);
 }
 
 /* scan buf[] for '~' before sending data to the peer */
 
-static int
-simple_escape_filter(Channel *c, char *buf, int len)
+/* Helper: allocate a new escape_filter_ctx and fill in its escape char */
+void *
+client_new_escape_filter_ctx(int escape_char)
+{
+        struct escape_filter_ctx *ret;
+
+        ret = xmalloc(sizeof(*ret));
+        ret->escape_pending = 0;
+        ret->escape_char = escape_char;
+        return (void *)ret;
+}
+
+/* Free the escape filter context on channel free */
+void
+client_filter_cleanup(int cid, void *ctx)
+{
+        xfree(ctx);
+}
+
+int
+client_simple_escape_filter(Channel *c, char *buf, int len)
 {
-        /* XXX we assume c->extended is writeable */
-        return process_escapes(&c->input, &c->output, &c->extended, buf, len);
+        if (c->extended_usage != CHAN_EXTENDED_WRITE)
+                return 0;
+
+        return process_escapes(c, &c->input, &c->output, &c->extended,
+            buf, len);
 }
 
 static void
@@ -1369,6 +1298,7 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
         fd_set *readset = NULL, *writeset = NULL;
         double start_time, total_time;
         int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
+        u_int64_t ibytes, obytes;
         u_int nalloc = 0;
         char buf[100];
 
@@ -1377,7 +1307,7 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
         start_time = get_current_time();
 
         /* Initialize variables. */
-        escape_pending = 0;
+        escape_pending1 = 0;
         last_was_cr = 1;
         exit_status = -1;
         stdin_eof = 0;
@@ -1385,8 +1315,8 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
         connection_in = packet_get_connection_in();
         connection_out = packet_get_connection_out();
         max_fd = MAX(connection_in, connection_out);
-        if (control_fd != -1)
-                max_fd = MAX(max_fd, control_fd);
+        if (muxserver_sock != -1)
+                max_fd = MAX(max_fd, muxserver_sock);
 
         if (!compat20) {
                 /* enable nonblocking unless tty */
@@ -1400,11 +1330,8 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
                 max_fd = MAX(max_fd, fileno(stdout));
                 max_fd = MAX(max_fd, fileno(stderr));
         }
-        stdin_bytes = 0;
-        stdout_bytes = 0;
-        stderr_bytes = 0;
         quit_pending = 0;
-        escape_char = escape_char_arg;
+        escape_char1 = escape_char_arg;
 
         /* Initialize buffers. */
         buffer_init(&stdin_buffer);
@@ -1432,9 +1359,11 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
 
         if (compat20) {
                 session_ident = ssh2_chan_id;
-                if (escape_char != SSH_ESCAPECHAR_NONE)
+                if (escape_char_arg != SSH_ESCAPECHAR_NONE)
                         channel_register_filter(session_ident,
-                            simple_escape_filter, NULL);
+                            client_simple_escape_filter, NULL,
+                            client_filter_cleanup,
+                            client_new_escape_filter_ctx(escape_char_arg));
                 if (session_ident != -1)
                         channel_register_cleanup(session_ident,
                             client_channel_closed, 0);
@@ -1506,7 +1435,10 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
                 client_process_net_input(readset);
 
                 /* Accept control connections.  */
-                client_process_control(readset);
+                if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) {
+                        if (muxserver_accept_control())
+                                quit_pending = 1;
+                }
 
                 if (quit_pending)
                         break;
@@ -1521,7 +1453,10 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
                         client_process_output(writeset);
                 }
 
-                /* Send as much buffered packet data as possible to the sender. */
+                /*
+                 * Send as much buffered packet data as possible to the
+                 * sender.
+                 */
                 if (FD_ISSET(connection_out, writeset))
                         packet_write_poll();
         }
@@ -1566,7 +1501,8 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
          * that the connection has been closed.
          */
         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
-                snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
+                snprintf(buf, sizeof buf,
+                    "Connection to %.64s closed.\r\n", host);
                 buffer_append(&stderr_buffer, buf, strlen(buf));
         }
 
@@ -1579,7 +1515,6 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
                         break;
                 }
                 buffer_consume(&stdout_buffer, len);
-                stdout_bytes += len;
         }
 
         /* Output any buffered data for stderr. */
@@ -1591,7 +1526,6 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
                         break;
                 }
                 buffer_consume(&stderr_buffer, len);
-                stderr_bytes += len;
         }
 
         /* Clear and free any buffers. */
@@ -1602,13 +1536,13 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
 
         /* Report bytes transferred, and transfer rates. */
         total_time = get_current_time() - start_time;
-        debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
-            stdin_bytes, stdout_bytes, stderr_bytes, total_time);
+        packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes);
+        packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes);
+        verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds",
+            obytes, ibytes, total_time);
         if (total_time > 0)
-                debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
-                    stdin_bytes / total_time, stdout_bytes / total_time,
-                    stderr_bytes / total_time);
-
+                verbose("Bytes per second: sent %.1f, received %.1f",
+                    obytes / total_time, ibytes / total_time);
         /* Return the exit status of the program. */
         debug("Exit status %d", exit_status);
         return exit_status;
@@ -1699,7 +1633,6 @@ client_request_forwarded_tcpip(const char *request_type, int rchan)
         Channel *c = NULL;
         char *listen_address, *originator_address;
         int listen_port, originator_port;
-        int sock;
 
         /* Get rest of the packet */
         listen_address = packet_get_string(NULL);
@@ -1708,19 +1641,13 @@ client_request_forwarded_tcpip(const char *request_type, int rchan)
         originator_port = packet_get_int();
         packet_check_eom();
 
-        debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
-            listen_address, listen_port, originator_address, originator_port);
+        debug("client_request_forwarded_tcpip: listen %s port %d, "
+            "originator %s port %d", listen_address, listen_port,
+            originator_address, originator_port);
+
+        c = channel_connect_by_listen_address(listen_port,
+            "forwarded-tcpip", originator_address);
 
-        sock = channel_connect_by_listen_address(listen_port);
-        if (sock < 0) {
-                xfree(originator_address);
-                xfree(listen_address);
-                return NULL;
-        }
-        c = channel_new("forwarded-tcpip",
-            SSH_CHANNEL_CONNECTING, sock, sock, -1,
-            CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
-            originator_address, 1);
         xfree(originator_address);
         xfree(listen_address);
         return c;
@@ -1736,7 +1663,8 @@ client_request_x11(const char *request_type, int rchan)
 
         if (!options.forward_x11) {
                 error("Warning: ssh server tried X11 forwarding.");
-                error("Warning: this is probably a break-in attempt by a malicious server.");
+                error("Warning: this is probably a break-in attempt by a "
+                    "malicious server.");
                 return NULL;
         }
         originator = packet_get_string(NULL);
@@ -1769,7 +1697,8 @@ client_request_agent(const char *request_type, int rchan)
 
         if (!options.forward_agent) {
                 error("Warning: ssh server tried agent forwarding.");
-                error("Warning: this is probably a break-in attempt by a malicious server.");
+                error("Warning: this is probably a break-in attempt by a "
+                    "malicious server.");
                 return NULL;
         }
         sock = ssh_get_authentication_socket();
@@ -1777,7 +1706,7 @@ client_request_agent(const char *request_type, int rchan)
                 return NULL;
         c = channel_new("authentication agent connection",
             SSH_CHANNEL_OPEN, sock, sock, -1,
-            CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
+            CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
             "authentication agent connection", 1);
         c->force_drain = 1;
         return c;
@@ -1812,7 +1741,7 @@ client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun)
 #if defined(SSH_TUN_FILTER)
         if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
                 channel_register_filter(c->self, sys_tun_infilter,
-                    sys_tun_outfilter);
+                    sys_tun_outfilter, NULL, NULL);
 #endif
 
         packet_start(SSH2_MSG_CHANNEL_OPEN);
@@ -1895,7 +1824,11 @@ client_input_channel_req(int type, u_int32_t seq, void *ctxt)
         if (id == -1) {
                 error("client_input_channel_req: request for channel -1");
         } else if ((c = channel_lookup(id)) == NULL) {
-                error("client_input_channel_req: channel %d: unknown channel", id);
+                error("client_input_channel_req: channel %d: "
+                    "unknown channel", id);
+        } else if (strcmp(rtype, "eow@openssh.com") == 0) {
+                packet_check_eom();
+                chan_rcvd_eow(c);
         } else if (strcmp(rtype, "exit-status") == 0) {
                 exitval = packet_get_int();
                 if (id == session_ident) {
@@ -1940,8 +1873,7 @@ client_input_global_request(int type, u_int32_t seq, void *ctxt)
 
 void
 client_session2_setup(int id, int want_tty, int want_subsystem,
-    const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env,
-    dispatch_fn *subsys_repl)
+    const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env)
 {
         int len;
         Channel *c = NULL;
@@ -1953,20 +1885,21 @@ client_session2_setup(int id, int want_tty, int want_subsystem,
 
         if (want_tty) {
                 struct winsize ws;
-                struct termios tio;
 
                 /* Store window size in the packet. */
                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
                         memset(&ws, 0, sizeof(ws));
 
-                channel_request_start(id, "pty-req", 0);
+                channel_request_start(id, "pty-req", 1);
+                client_expect_confirm(id, "PTY allocation", 0);
                 packet_put_cstring(term != NULL ? term : "");
                 packet_put_int((u_int)ws.ws_col);
                 packet_put_int((u_int)ws.ws_row);
                 packet_put_int((u_int)ws.ws_xpixel);
                 packet_put_int((u_int)ws.ws_ypixel);
-                tio = get_saved_tio();
-                tty_make_modes(-1, tiop != NULL ? tiop : &tio);
+                if (tiop == NULL)
+                        tiop = get_saved_tio();
+                tty_make_modes(-1, tiop);
                 packet_send();
                 /* XXX wait for reply */
                 c->client_tty = 1;
@@ -2014,22 +1947,21 @@ client_session2_setup(int id, int want_tty, int want_subsystem,
                 if (len > 900)
                         len = 900;
                 if (want_subsystem) {
-                        debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd));
-                        channel_request_start(id, "subsystem", subsys_repl != NULL);
-                        if (subsys_repl != NULL) {
-                                /* register callback for reply */
-                                /* XXX we assume that client_loop has already been called */
-                                dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl);
-                                dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl);
-                        }
+                        debug("Sending subsystem: %.*s",
+                            len, (u_char*)buffer_ptr(cmd));
+                        channel_request_start(id, "subsystem", 1);
+                        client_expect_confirm(id, "subsystem", 1);
                 } else {
-                        debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd));
-                        channel_request_start(id, "exec", 0);
+                        debug("Sending command: %.*s",
+                            len, (u_char*)buffer_ptr(cmd));
+                        channel_request_start(id, "exec", 1);
+                        client_expect_confirm(id, "exec", 1);
                 }
                 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
                 packet_send();
         } else {
-                channel_request_start(id, "shell", 0);
+                channel_request_start(id, "shell", 1);
+                client_expect_confirm(id, "shell", 1);
                 packet_send();
         }
 }
@@ -2048,6 +1980,8 @@ client_init_dispatch_20(void)
         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
+        dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
+        dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
 
         /* rekeying */
@@ -2057,6 +1991,7 @@ client_init_dispatch_20(void)
         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
 }
+
 static void
 client_init_dispatch_13(void)
 {
@@ -2076,6 +2011,7 @@ client_init_dispatch_13(void)
         dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
             &x11_input_open : &deny_input_open);
 }
+
 static void
 client_init_dispatch_15(void)
 {
@@ -2083,6 +2019,7 @@ client_init_dispatch_15(void)
         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
 }
+
 static void
 client_init_dispatch(void)
 {
@@ -2100,7 +2037,7 @@ cleanup_exit(int i)
 {
         leave_raw_mode();
         leave_non_blocking();
-        if (options.control_path != NULL && control_fd != -1)
+        if (options.control_path != NULL && muxserver_sock != -1)
                 unlink(options.control_path);
         _exit(i);
 }