X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/48e671d5303c70deea9cde5c1a785882c0501f6e..27c47c0ad07c3e63270ef33b5f3f7226d4d58582:/nchan.c

diff --git a/nchan.c b/nchan.c
index 8021dd6c..2680f0a6 100644
--- a/nchan.c
+++ b/nchan.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999 Markus Friedl.  All rights reserved.
+ * Copyright (c) 1999, 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
@@ -9,11 +9,6 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *      This product includes software developed by Markus Friedl.
- * 4. The name of the author may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
@@ -28,152 +23,228 @@
  */
 
 #include "includes.h"
-RCSID("$Id$");
-
-#include "ssh.h"
+RCSID("$OpenBSD: nchan.c,v 1.32 2001/10/10 22:18:47 markus Exp $");
 
+#include "ssh1.h"
+#include "ssh2.h"
 #include "buffer.h"
 #include "packet.h"
 #include "channels.h"
-#include "nchan.h"
+#include "compat.h"
+#include "log.h"
 
-static void chan_send_ieof(Channel *c);
-static void chan_send_oclose(Channel *c);
-static void chan_shutdown_write(Channel *c);
-static void chan_shutdown_read(Channel *c);
-static void chan_delete_if_full_closed(Channel *c);
+/*
+ * SSH Protocol 1.5 aka New Channel Protocol
+ * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
+ * Written by Markus Friedl in October 1999
+ *
+ * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
+ * tear down of channels:
+ *
+ * 1.3:	strict request-ack-protocol:
+ * 	CLOSE	->
+ * 		<-  CLOSE_CONFIRM
+ *
+ * 1.5:	uses variations of:
+ * 	IEOF	->
+ * 		<-  OCLOSE
+ * 		<-  IEOF
+ * 	OCLOSE	->
+ * 	i.e. both sides have to close the channel
+ *
+ * 2.0: the EOF messages are optional
+ *
+ * See the debugging output from 'ssh -v' and 'sshd -d' of
+ * ssh-1.2.27 as an example.
+ *
+ */
 
+/* functions manipulating channel states */
 /*
  * EVENTS update channel input/output states execute ACTIONS
  */
-
 /* events concerning the INPUT from socket for channel (istate) */
-void
-chan_rcvd_oclose(Channel *c)
+chan_event_fn *chan_rcvd_oclose			= NULL;
+chan_event_fn *chan_read_failed			= NULL;
+chan_event_fn *chan_ibuf_empty			= NULL;
+/* events concerning the OUTPUT from channel for socket (ostate) */
+chan_event_fn *chan_rcvd_ieof			= NULL;
+chan_event_fn *chan_write_failed		= NULL;
+chan_event_fn *chan_obuf_empty			= NULL;
+/*
+ * ACTIONS: should never update the channel states
+ */
+static void	chan_send_ieof1(Channel *);
+static void	chan_send_oclose1(Channel *);
+static void	chan_send_close2(Channel *);
+static void	chan_send_eof2(Channel *);
+
+/* helper */
+static void	chan_shutdown_write(Channel *);
+static void	chan_shutdown_read(Channel *);
+
+/*
+ * SSH1 specific implementation of event functions
+ */
+
+static void
+chan_rcvd_oclose1(Channel *c)
 {
+	debug("channel %d: rcvd oclose", c->self);
 	switch (c->istate) {
 	case CHAN_INPUT_WAIT_OCLOSE:
-		debug("channel %d: INPUT_WAIT_OCLOSE -> INPUT_CLOSED [rcvd OCLOSE]", c->self);
+		debug("channel %d: input wait_oclose -> closed", c->self);
 		c->istate = CHAN_INPUT_CLOSED;
 		break;
 	case CHAN_INPUT_OPEN:
-		debug("channel %d: INPUT_OPEN -> INPUT_CLOSED [rvcd OCLOSE, send IEOF]", c->self);
+		debug("channel %d: input open -> closed", c->self);
 		chan_shutdown_read(c);
-		chan_send_ieof(c);
+		chan_send_ieof1(c);
 		c->istate = CHAN_INPUT_CLOSED;
 		break;
 	case CHAN_INPUT_WAIT_DRAIN:
 		/* both local read_failed and remote write_failed  */
-		log("channel %d: INPUT_WAIT_DRAIN -> INPUT_CLOSED [rvcd OCLOSE, send IEOF]", c->self);
-		debug("channel %d: INPUT_WAIT_DRAIN -> INPUT_CLOSED [rvcd OCLOSE, send IEOF]", c->self);
-		chan_send_ieof(c);
+		log("channel %d: input drain -> closed", c->self);
+		chan_send_ieof1(c);
 		c->istate = CHAN_INPUT_CLOSED;
 		break;
 	default:
-		error("protocol error: chan_rcvd_oclose %d for istate %d", c->self, c->istate);
+		error("channel %d: protocol error: rcvd_oclose for istate %d",
+		    c->self, c->istate);
 		return;
 	}
-	chan_delete_if_full_closed(c);
 }
-void
-chan_read_failed(Channel *c)
+static void
+chan_read_failed_12(Channel *c)
 {
+	debug("channel %d: read failed", c->self);
 	switch (c->istate) {
 	case CHAN_INPUT_OPEN:
-		debug("channel %d: INPUT_OPEN -> INPUT_WAIT_DRAIN [read failed]", c->self);
+		debug("channel %d: input open -> drain", c->self);
 		chan_shutdown_read(c);
 		c->istate = CHAN_INPUT_WAIT_DRAIN;
+#if 0
+		if (buffer_len(&c->input) == 0) {
+			debug("channel %d: input: no drain shortcut", c->self);
+			chan_ibuf_empty(c);
+		}
+#endif
 		break;
 	default:
-		error("internal error: we do not read, but chan_read_failed %d for istate %d",
-		      c->self, c->istate);
+		error("channel %d: chan_read_failed for istate %d",
+		    c->self, c->istate);
 		break;
 	}
 }
-void
-chan_ibuf_empty(Channel *c)
+static void
+chan_ibuf_empty1(Channel *c)
 {
+	debug("channel %d: ibuf empty", c->self);
 	if (buffer_len(&c->input)) {
-		error("internal error: chan_ibuf_empty %d for non empty buffer", c->self);
+		error("channel %d: chan_ibuf_empty for non empty buffer",
+		    c->self);
 		return;
 	}
 	switch (c->istate) {
 	case CHAN_INPUT_WAIT_DRAIN:
-		debug("channel %d: INPUT_WAIT_DRAIN -> INPUT_WAIT_OCLOSE [inbuf empty, send IEOF]", c->self);
-		chan_send_ieof(c);
+		debug("channel %d: input drain -> wait_oclose", c->self);
+		chan_send_ieof1(c);
 		c->istate = CHAN_INPUT_WAIT_OCLOSE;
 		break;
 	default:
-		error("internal error: chan_ibuf_empty %d for istate %d", c->self, c->istate);
+		error("channel %d: chan_ibuf_empty for istate %d",
+		    c->self, c->istate);
 		break;
 	}
 }
-
-/* events concerning the OUTPUT from channel for socket (ostate) */
-void
-chan_rcvd_ieof(Channel *c)
+static void
+chan_rcvd_ieof1(Channel *c)
 {
+	debug("channel %d: rcvd ieof", c->self);
+	if (c->type != SSH_CHANNEL_OPEN) {
+		debug("channel %d: non-open", c->self);
+		if (c->istate == CHAN_INPUT_OPEN) {
+			debug("channel %d: non-open: input open -> wait_oclose",
+			    c->self);
+			chan_shutdown_read(c);
+			chan_send_ieof1(c);
+			c->istate = CHAN_INPUT_WAIT_OCLOSE;
+		} else {
+			error("channel %d: non-open: istate %d != open",
+			    c->self, c->istate);
+		}
+		if (c->ostate == CHAN_OUTPUT_OPEN) {
+			debug("channel %d: non-open: output open -> closed",
+			    c->self);
+			chan_send_oclose1(c);
+			c->ostate = CHAN_OUTPUT_CLOSED;
+		} else {
+			error("channel %d: non-open: ostate %d != open",
+			    c->self, c->ostate);
+		}
+		return;
+	}
 	switch (c->ostate) {
 	case CHAN_OUTPUT_OPEN:
-		debug("channel %d: OUTPUT_OPEN -> OUTPUT_WAIT_DRAIN [rvcd IEOF]", c->self);
+		debug("channel %d: output open -> drain", c->self);
 		c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
 		break;
 	case CHAN_OUTPUT_WAIT_IEOF:
-		debug("channel %d: OUTPUT_WAIT_IEOF -> OUTPUT_CLOSED [rvcd IEOF]", c->self);
+		debug("channel %d: output wait_ieof -> closed", c->self);
 		c->ostate = CHAN_OUTPUT_CLOSED;
-		chan_delete_if_full_closed(c);
 		break;
 	default:
-		error("protocol error: chan_rcvd_ieof %d for ostate %d", c->self, c->ostate);
+		error("channel %d: protocol error: rcvd_ieof for ostate %d",
+		    c->self, c->ostate);
 		break;
 	}
 }
-void
-chan_write_failed(Channel *c)
+static void
+chan_write_failed1(Channel *c)
 {
+	debug("channel %d: write failed", c->self);
 	switch (c->ostate) {
 	case CHAN_OUTPUT_OPEN:
-		debug("channel %d: OUTPUT_OPEN -> OUTPUT_WAIT_IEOF [write failed]", c->self);
-		chan_send_oclose(c);
+		debug("channel %d: output open -> wait_ieof", c->self);
+		chan_send_oclose1(c);
 		c->ostate = CHAN_OUTPUT_WAIT_IEOF;
 		break;
 	case CHAN_OUTPUT_WAIT_DRAIN:
-		debug("channel %d: OUTPUT_WAIT_DRAIN -> OUTPUT_CLOSED [write failed]", c->self);
-		chan_send_oclose(c);
+		debug("channel %d: output wait_drain -> closed", c->self);
+		chan_send_oclose1(c);
 		c->ostate = CHAN_OUTPUT_CLOSED;
-		chan_delete_if_full_closed(c);
 		break;
 	default:
-		error("internal error: chan_write_failed %d for ostate %d", c->self, c->ostate);
+		error("channel %d: chan_write_failed for ostate %d",
+		    c->self, c->ostate);
 		break;
 	}
 }
-void
-chan_obuf_empty(Channel *c)
+static void
+chan_obuf_empty1(Channel *c)
 {
+	debug("channel %d: obuf empty", c->self);
 	if (buffer_len(&c->output)) {
-		debug("internal error: chan_obuf_empty %d for non empty buffer", c->self);
+		error("channel %d: chan_obuf_empty for non empty buffer",
+		    c->self);
 		return;
 	}
 	switch (c->ostate) {
 	case CHAN_OUTPUT_WAIT_DRAIN:
-		debug("channel %d: OUTPUT_WAIT_DRAIN -> OUTPUT_CLOSED [obuf empty, send OCLOSE]", c->self);
-		chan_send_oclose(c);
+		debug("channel %d: output drain -> closed", c->self);
+		chan_send_oclose1(c);
 		c->ostate = CHAN_OUTPUT_CLOSED;
-		chan_delete_if_full_closed(c);
 		break;
 	default:
-		error("internal error: chan_obuf_empty %d for ostate %d", c->self, c->ostate);
+		error("channel %d: internal error: obuf_empty for ostate %d",
+		    c->self, c->ostate);
 		break;
 	}
 }
-
-/*
- * ACTIONS: should never update the channel states: c->istate or c->ostate
- */
 static void
-chan_send_ieof(Channel *c)
+chan_send_ieof1(Channel *c)
 {
+	debug("channel %d: send ieof", c->self);
 	switch (c->istate) {
 	case CHAN_INPUT_OPEN:
 	case CHAN_INPUT_WAIT_DRAIN:
@@ -182,13 +253,15 @@ chan_send_ieof(Channel *c)
 		packet_send();
 		break;
 	default:
-		error("internal error: channel %d: cannot send IEOF for istate %d", c->self, c->istate);
+		error("channel %d: cannot send ieof for istate %d",
+		    c->self, c->istate);
 		break;
 	}
 }
 static void
-chan_send_oclose(Channel *c)
+chan_send_oclose1(Channel *c)
 {
+	debug("channel %d: send oclose", c->self);
 	switch (c->ostate) {
 	case CHAN_OUTPUT_OPEN:
 	case CHAN_OUTPUT_WAIT_DRAIN:
@@ -199,40 +272,289 @@ chan_send_oclose(Channel *c)
 		packet_send();
 		break;
 	default:
-		error("internal error: channel %d: cannot send OCLOSE for ostate %d", c->self, c->istate);
+		error("channel %d: cannot send oclose for ostate %d",
+		     c->self, c->ostate);
 		break;
 	}
 }
 
-/* helper */
+/*
+ * the same for SSH2
+ */
 static void
-chan_shutdown_write(Channel *c)
+chan_rcvd_oclose2(Channel *c)
 {
-	/* shutdown failure is allowed if write failed already */
-	debug("channel %d: shutdown_write", c->self);
-	if (shutdown(c->sock, SHUT_WR) < 0)
-		debug("chan_shutdown_write failed for #%d/fd%d: %.100s",
-		      c->self, c->sock, strerror(errno));
+	debug("channel %d: rcvd close", c->self);
+	if (c->flags & CHAN_CLOSE_RCVD)
+		error("channel %d: protocol error: close rcvd twice", c->self);
+	c->flags |= CHAN_CLOSE_RCVD;
+	if (c->type == SSH_CHANNEL_LARVAL) {
+		/* tear down larval channels immediately */
+		c->ostate = CHAN_OUTPUT_CLOSED;
+		c->istate = CHAN_INPUT_CLOSED;
+		return;
+	}
+	switch (c->ostate) {
+	case CHAN_OUTPUT_OPEN:
+		/*
+		 * wait until a data from the channel is consumed if a CLOSE
+		 * is received
+		 */
+		debug("channel %d: output open -> drain", c->self);
+		c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
+		break;
+	}
+	switch (c->istate) {
+	case CHAN_INPUT_OPEN:
+		debug("channel %d: input open -> closed", c->self);
+		chan_shutdown_read(c);
+		break;
+	case CHAN_INPUT_WAIT_DRAIN:
+		debug("channel %d: input drain -> closed", c->self);
+		chan_send_eof2(c);
+		break;
+	}
+	c->istate = CHAN_INPUT_CLOSED;
 }
 static void
-chan_shutdown_read(Channel *c)
+chan_ibuf_empty2(Channel *c)
+{
+	debug("channel %d: ibuf empty", c->self);
+	if (buffer_len(&c->input)) {
+		error("channel %d: chan_ibuf_empty for non empty buffer",
+		     c->self);
+		return;
+	}
+	switch (c->istate) {
+	case CHAN_INPUT_WAIT_DRAIN:
+		debug("channel %d: input drain -> closed", c->self);
+		if (!(c->flags & CHAN_CLOSE_SENT))
+			chan_send_eof2(c);
+		c->istate = CHAN_INPUT_CLOSED;
+		break;
+	default:
+		error("channel %d: chan_ibuf_empty for istate %d",
+		     c->self, c->istate);
+		break;
+	}
+}
+static void
+chan_rcvd_ieof2(Channel *c)
+{
+	debug("channel %d: rcvd eof", c->self);
+	if (c->ostate == CHAN_OUTPUT_OPEN) {
+		debug("channel %d: output open -> drain", c->self);
+		c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
+	}
+}
+static void
+chan_write_failed2(Channel *c)
 {
-	debug("channel %d: shutdown_read", c->self);
-	if (shutdown(c->sock, SHUT_RD) < 0)
-		error("chan_shutdown_read failed for #%d/fd%d [i%d o%d]: %.100s",
-		      c->self, c->sock, c->istate, c->ostate, strerror(errno));
+	debug("channel %d: write failed", c->self);
+	switch (c->ostate) {
+	case CHAN_OUTPUT_OPEN:
+		debug("channel %d: output open -> closed", c->self);
+		chan_shutdown_write(c); /* ?? */
+		c->ostate = CHAN_OUTPUT_CLOSED;
+		break;
+	case CHAN_OUTPUT_WAIT_DRAIN:
+		debug("channel %d: output drain -> closed", c->self);
+		chan_shutdown_write(c);
+		c->ostate = CHAN_OUTPUT_CLOSED;
+		break;
+	default:
+		error("channel %d: chan_write_failed for ostate %d",
+		    c->self, c->ostate);
+		break;
+	}
+}
+static void
+chan_obuf_empty2(Channel *c)
+{
+	debug("channel %d: obuf empty", c->self);
+	if (buffer_len(&c->output)) {
+		error("channel %d: chan_obuf_empty for non empty buffer",
+		    c->self);
+		return;
+	}
+	switch (c->ostate) {
+	case CHAN_OUTPUT_WAIT_DRAIN:
+		debug("channel %d: output drain -> closed", c->self);
+		chan_shutdown_write(c);
+		c->ostate = CHAN_OUTPUT_CLOSED;
+		break;
+	default:
+		error("channel %d: chan_obuf_empty for ostate %d",
+		    c->self, c->ostate);
+		break;
+	}
 }
 static void
-chan_delete_if_full_closed(Channel *c)
+chan_send_eof2(Channel *c)
 {
-	if (c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED) {
-		debug("channel %d: full closed", c->self);
-		channel_free(c->self);
+	debug("channel %d: send eof", c->self);
+	switch (c->istate) {
+	case CHAN_INPUT_WAIT_DRAIN:
+		packet_start(SSH2_MSG_CHANNEL_EOF);
+		packet_put_int(c->remote_id);
+		packet_send();
+		break;
+	default:
+		error("channel %d: cannot send eof for istate %d",
+		    c->self, c->istate);
+		break;
 	}
 }
+static void
+chan_send_close2(Channel *c)
+{
+	debug("channel %d: send close", c->self);
+	if (c->ostate != CHAN_OUTPUT_CLOSED ||
+	    c->istate != CHAN_INPUT_CLOSED) {
+		error("channel %d: cannot send close for istate/ostate %d/%d",
+		    c->self, c->istate, c->ostate);
+	} else if (c->flags & CHAN_CLOSE_SENT) {
+		error("channel %d: already sent close", c->self);
+	} else {
+		packet_start(SSH2_MSG_CHANNEL_CLOSE);
+		packet_put_int(c->remote_id);
+		packet_send();
+		c->flags |= CHAN_CLOSE_SENT;
+	}
+}
+
+/* shared */
+
+void
+chan_mark_dead(Channel *c)
+{
+	c->type = SSH_CHANNEL_ZOMBIE;
+}
+
+int
+chan_is_dead(Channel *c, int send)
+{
+	if (c->type == SSH_CHANNEL_ZOMBIE) {
+		debug("channel %d: zombie", c->self);
+		return 1;
+	}
+	if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
+		return 0;
+	if (!compat20) {
+		debug("channel %d: is dead", c->self);
+		return 1;
+	}
+	/*
+	 * we have to delay the close message if the efd (for stderr) is
+	 * still active
+	 */
+	if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
+	    buffer_len(&c->extended) > 0)
+#if 0
+	    || ((c->extended_usage == CHAN_EXTENDED_READ) &&
+	    c->efd != -1)
+#endif
+	    ) {
+		debug2("channel %d: active efd: %d len %d type %s",
+		    c->self, c->efd, buffer_len(&c->extended),
+		    c->extended_usage==CHAN_EXTENDED_READ ?
+		       "read": "write");
+	} else {
+		if (!(c->flags & CHAN_CLOSE_SENT)) {
+			if (send) {
+				chan_send_close2(c);
+			} else {
+				/* channel would be dead if we sent a close */
+				if (c->flags & CHAN_CLOSE_RCVD) {
+					debug("channel %d: almost dead",
+					    c->self);
+					return 1;
+				}
+			}
+		}
+		if ((c->flags & CHAN_CLOSE_SENT) &&
+		    (c->flags & CHAN_CLOSE_RCVD)) {
+			debug("channel %d: is dead", c->self);
+			return 1;
+		}
+	}
+	return 0;
+}
+
 void
 chan_init_iostates(Channel *c)
 {
 	c->ostate = CHAN_OUTPUT_OPEN;
 	c->istate = CHAN_INPUT_OPEN;
+	c->flags = 0;
+}
+
+/* init */
+void
+chan_init(void)
+{
+	if (compat20) {
+		chan_rcvd_oclose		= chan_rcvd_oclose2;
+		chan_read_failed		= chan_read_failed_12;
+		chan_ibuf_empty			= chan_ibuf_empty2;
+
+		chan_rcvd_ieof			= chan_rcvd_ieof2;
+		chan_write_failed		= chan_write_failed2;
+		chan_obuf_empty			= chan_obuf_empty2;
+	} else {
+		chan_rcvd_oclose		= chan_rcvd_oclose1;
+		chan_read_failed		= chan_read_failed_12;
+		chan_ibuf_empty			= chan_ibuf_empty1;
+
+		chan_rcvd_ieof			= chan_rcvd_ieof1;
+		chan_write_failed		= chan_write_failed1;
+		chan_obuf_empty			= chan_obuf_empty1;
+	}
+}
+
+/* helper */
+static void
+chan_shutdown_write(Channel *c)
+{
+	buffer_consume(&c->output, buffer_len(&c->output));
+	if (compat20 && c->type == SSH_CHANNEL_LARVAL)
+		return;
+	/* shutdown failure is allowed if write failed already */
+	debug("channel %d: close_write", c->self);
+	if (c->sock != -1) {
+		if (shutdown(c->sock, SHUT_WR) < 0)
+			debug("channel %d: chan_shutdown_write: "
+			    "shutdown() failed for fd%d: %.100s",
+			    c->self, c->sock, strerror(errno));
+	} else {
+		if (channel_close_fd(&c->wfd) < 0)
+			log("channel %d: chan_shutdown_write: "
+			    "close() failed for fd%d: %.100s",
+			    c->self, c->wfd, strerror(errno));
+	}
+}
+static void
+chan_shutdown_read(Channel *c)
+{
+	if (compat20 && c->type == SSH_CHANNEL_LARVAL)
+		return;
+	debug("channel %d: close_read", c->self);
+	if (c->sock != -1) {
+		/*
+		 * shutdown(sock, SHUT_READ) may return ENOTCONN if the
+		 * write side has been closed already. (bug on Linux)
+		 * HP-UX may return ENOTCONN also.
+		 */
+		if (shutdown(c->sock, SHUT_RD) < 0
+		    && errno != ENOTCONN)
+			error("channel %d: chan_shutdown_read: "
+			    "shutdown() failed for fd%d [i%d o%d]: %.100s",
+			    c->self, c->sock, c->istate, c->ostate,
+			    strerror(errno));
+	} else {
+		if (channel_close_fd(&c->rfd) < 0)
+			log("channel %d: chan_shutdown_read: "
+			    "close() failed for fd%d: %.100s",
+			    c->self, c->rfd, strerror(errno));
+	}
 }