- djm@cvs.openbsd.org 2011/04/17 22:42:42

     [PROTOCOL.mux clientloop.c clientloop.h mux.c ssh.1 ssh.c]
     allow graceful shutdown of multiplexing: request that a mux server
     removes its listener socket and refuse future multiplexing requests;
     ok markus@

1 files changed, 85 insertions, 1 deletions

diff --git a/mux.c b/mux.c
index e370462db..09468359f 100644
--- a/mux.c
+++ b/mux.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mux.c,v 1.24 2011/01/13 21:54:53 djm Exp $ */
+/* $OpenBSD: mux.c,v 1.25 2011/04/17 22:42:41 djm Exp $ */
 /*
  * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
  *
@@ -146,6 +146,7 @@ struct mux_master_state {
 #define MUX_C_OPEN_FWD          0x10000006
 #define MUX_C_CLOSE_FWD         0x10000007
 #define MUX_C_NEW_STDIO_FWD     0x10000008
+#define MUX_C_STOP_LISTENING    0x10000009
 #define MUX_S_OK                0x80000001
 #define MUX_S_PERMISSION_DENIED 0x80000002
 #define MUX_S_FAILURE           0x80000003
@@ -168,6 +169,7 @@ static int process_mux_terminate(u_int, Channel *, Buffer *, Buffer *);
 static int process_mux_open_fwd(u_int, Channel *, Buffer *, Buffer *);
 static int process_mux_close_fwd(u_int, Channel *, Buffer *, Buffer *);
 static int process_mux_stdio_fwd(u_int, Channel *, Buffer *, Buffer *);
+static int process_mux_stop_listening(u_int, Channel *, Buffer *, Buffer *);
 
 static const struct {
         u_int type;
@@ -180,6 +182,7 @@ static const struct {
         { MUX_C_OPEN_FWD, process_mux_open_fwd },
         { MUX_C_CLOSE_FWD, process_mux_close_fwd },
         { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd },
+        { MUX_C_STOP_LISTENING, process_mux_stop_listening },
         { 0, NULL }
 };
 
@@ -915,6 +918,39 @@ process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
         return 0;
 }
 
+static int
+process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+        debug("%s: channel %d: stop listening", __func__, c->self);
+
+        if (options.control_master == SSHCTL_MASTER_ASK ||
+            options.control_master == SSHCTL_MASTER_AUTO_ASK) {
+                if (!ask_permission("Disable further multiplexing on shared "
+                    "connection to %s? ", host)) {
+                        debug2("%s: stop listen refused by user", __func__);
+                        buffer_put_int(r, MUX_S_PERMISSION_DENIED);
+                        buffer_put_int(r, rid);
+                        buffer_put_cstring(r, "Permission denied");
+                        return 0;
+                }
+        }
+
+        if (mux_listener_channel != NULL) {
+                channel_free(mux_listener_channel);
+                client_stop_mux();
+                xfree(options.control_path);
+                options.control_path = NULL;
+                mux_listener_channel = NULL;
+                muxserver_sock = -1;
+        }
+
+        /* prepare reply */
+        buffer_put_int(r, MUX_S_OK);
+        buffer_put_int(r, rid);
+
+        return 0;
+}
+
 /* Channel callbacks fired on read/write from mux slave fd */
 static int
 mux_master_read_cb(Channel *c)
@@ -1813,6 +1849,50 @@ mux_client_request_stdio_fwd(int fd)
         fatal("%s: master returned unexpected message %u", __func__, type);
 }
 
+static void
+mux_client_request_stop_listening(int fd)
+{
+        Buffer m;
+        char *e;
+        u_int type, rid;
+
+        debug3("%s: entering", __func__);
+
+        buffer_init(&m);
+        buffer_put_int(&m, MUX_C_STOP_LISTENING);
+        buffer_put_int(&m, muxclient_request_id);
+
+        if (mux_client_write_packet(fd, &m) != 0)
+                fatal("%s: write packet: %s", __func__, strerror(errno));
+
+        buffer_clear(&m);
+
+        /* Read their reply */
+        if (mux_client_read_packet(fd, &m) != 0)
+                fatal("%s: read from master failed: %s",
+                    __func__, strerror(errno));
+
+        type = buffer_get_int(&m);
+        if ((rid = buffer_get_int(&m)) != muxclient_request_id)
+                fatal("%s: out of sequence reply: my id %u theirs %u",
+                    __func__, muxclient_request_id, rid);
+        switch (type) {
+        case MUX_S_OK:
+                break;
+        case MUX_S_PERMISSION_DENIED:
+                e = buffer_get_string(&m, NULL);
+                fatal("Master refused stop listening request: %s", e);
+        case MUX_S_FAILURE:
+                e = buffer_get_string(&m, NULL);
+                fatal("%s: stop listening request failed: %s", __func__, e);
+        default:
+                fatal("%s: unexpected response from master 0x%08x",
+                    __func__, type);
+        }
+        buffer_free(&m);
+        muxclient_request_id++;
+}
+
 /* Multiplex client main loop. */
 void
 muxclient(const char *path)
@@ -1906,6 +1986,10 @@ muxclient(const char *path)
         case SSHMUX_COMMAND_STDIO_FWD:
                 mux_client_request_stdio_fwd(sock);
                 exit(0);
+        case SSHMUX_COMMAND_STOP:
+                mux_client_request_stop_listening(sock);
+                fprintf(stderr, "Stop listening request sent.\r\n");
+                exit(0);
         default:
                 fatal("unrecognised muxclient_command %d", muxclient_command);
         }