From: mouring <mouring>
Date: Sat, 5 May 2001 04:09:47 +0000 (+0000)
Subject:    - markus@cvs.openbsd.org 2001/05/04 23:47:34
X-Git-Tag: V_2_9_9_P1~390
X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/commitdiff_plain/719fc62ff24f296bb23e3419eeadb21758c8b8bc

   - markus@cvs.openbsd.org 2001/05/04 23:47:34
     [channels.c channels.h clientloop.c nchan.c nchan.h serverloop.c ssh.c]
     move to Channel **channels (instead of Channel *channels), fixes realloc
     problems.  channel_new now returns a Channel *, favour Channel * over
     channel id.  remove old channel_allocate interface.
---

diff --git a/ChangeLog b/ChangeLog
index 4d533ea7..3aa4add0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,11 @@
      [channels.c]
      channel_new() reallocs channels[], we cannot use Channel *c after calling
      channel_new(), XXX fix this in the future...
+   - markus@cvs.openbsd.org 2001/05/04 23:47:34
+     [channels.c channels.h clientloop.c nchan.c nchan.h serverloop.c ssh.c]
+     move to Channel **channels (instead of Channel *channels), fixes realloc 
+     problems.  channel_new now returns a Channel *, favour Channel * over 
+     channel id.  remove old channel_allocate interface.
 
 20010504
  - OpenBSD CVS Sync
diff --git a/channels.c b/channels.c
index 503a8145..2bb0e985 100644
--- a/channels.c
+++ b/channels.c
@@ -40,7 +40,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: channels.c,v 1.112 2001/05/04 14:34:34 markus Exp $");
+RCSID("$OpenBSD: channels.c,v 1.113 2001/05/04 23:47:33 markus Exp $");
 
 #include <openssl/rsa.h>
 #include <openssl/dsa.h>
@@ -72,18 +72,17 @@ RCSID("$OpenBSD: channels.c,v 1.112 2001/05/04 14:34:34 markus Exp $");
  * Pointer to an array containing all allocated channels.  The array is
  * dynamically extended as needed.
  */
-static Channel *channels = NULL;
+static Channel **channels = NULL;
 
 /*
  * Size of the channel array.  All slots of the array must always be
- * initialized (at least the type field); unused slots are marked with type
- * SSH_CHANNEL_FREE.
+ * initialized (at least the type field); unused slots set to NULL
  */
 static int channels_alloc = 0;
 
 /*
  * Maximum file descriptor value used in any of the channels.  This is
- * updated in channel_allocate.
+ * updated in channel_new.
  */
 static int channel_max_fd = 0;
 
@@ -150,12 +149,13 @@ Channel *
 channel_lookup(int id)
 {
 	Channel *c;
+
 	if (id < 0 || id > channels_alloc) {
 		log("channel_lookup: %d: bad id", id);
 		return NULL;
 	}
-	c = &channels[id];
-	if (c->type == SSH_CHANNEL_FREE) {
+	c = channels[id];
+	if (c == NULL) {
 		log("channel_lookup: %d: bad id: channel free", id);
 		return NULL;
 	}
@@ -212,7 +212,7 @@ channel_register_fds(Channel *c, int rfd, int wfd, int efd,
  * remote_name to be freed.
  */
 
-int
+Channel *
 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
     int window, int maxpack, int extusage, char *remote_name, int nonblock)
 {
@@ -223,9 +223,9 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 	if (channels_alloc == 0) {
 		chan_init();
 		channels_alloc = 10;
-		channels = xmalloc(channels_alloc * sizeof(Channel));
+		channels = xmalloc(channels_alloc * sizeof(Channel *));
 		for (i = 0; i < channels_alloc; i++)
-			channels[i].type = SSH_CHANNEL_FREE;
+			channels[i] = NULL;
 		/*
 		 * Kludge: arrange a call to channel_stop_listening if we
 		 * terminate with fatal().
@@ -234,7 +234,7 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 	}
 	/* Try to find a free slot where to put the new channel. */
 	for (found = -1, i = 0; i < channels_alloc; i++)
-		if (channels[i].type == SSH_CHANNEL_FREE) {
+		if (channels[i] == NULL) {
 			/* Found a free slot. */
 			found = i;
 			break;
@@ -244,12 +244,12 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 		found = channels_alloc;
 		channels_alloc += 10;
 		debug2("channel: expanding %d", channels_alloc);
-		channels = xrealloc(channels, channels_alloc * sizeof(Channel));
+		channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
 		for (i = found; i < channels_alloc; i++)
-			channels[i].type = SSH_CHANNEL_FREE;
+			channels[i] = NULL;
 	}
-	/* Initialize and return new channel number. */
-	c = &channels[found];
+	/* Initialize and return new channel. */
+	c = channels[found] = xmalloc(sizeof(Channel));
 	buffer_init(&c->input);
 	buffer_init(&c->output);
 	buffer_init(&c->extended);
@@ -272,16 +272,9 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 	c->dettach_user = NULL;
 	c->input_filter = NULL;
 	debug("channel %d: new [%s]", found, remote_name);
-	return found;
-}
-/* old interface XXX */
-int
-channel_allocate(int type, int sock, char *remote_name)
-{
-	return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name, 1);
+	return c;
 }
 
-
 /* Close all channel fd/socket. */
 
 void
@@ -308,18 +301,16 @@ channel_close_fds(Channel *c)
 /* Free the channel and close its fd/socket. */
 
 void
-channel_free(int id)
+channel_free(Channel *c)
 {
-	Channel *c = channel_lookup(id);
-	char *s = channel_open_message();
+	char *s;
 
-	if (c == NULL)
-		packet_disconnect("channel free: bad local channel %d", id);
-	debug("channel_free: channel %d: status: %s", id, s);
+	s = channel_open_message();
+	debug("channel_free: channel %d: status: %s", c->self, s);
 	xfree(s);
 
 	if (c->dettach_user != NULL) {
-		debug("channel_free: channel %d: dettaching channel user", id);
+		debug("channel_free: channel %d: dettaching channel user", c->self);
 		c->dettach_user(c->self, NULL);
 	}
 	if (c->sock != -1)
@@ -328,11 +319,12 @@ channel_free(int id)
 	buffer_free(&c->input);
 	buffer_free(&c->output);
 	buffer_free(&c->extended);
-	c->type = SSH_CHANNEL_FREE;
 	if (c->remote_name) {
 		xfree(c->remote_name);
 		c->remote_name = NULL;
 	}
+	channels[c->self] = NULL;
+	xfree(c);
 }
 
 /*
@@ -428,7 +420,7 @@ void
 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
 {
 	if (buffer_len(&c->output) == 0)
-		channel_free(c->self);
+		chan_mark_dead(c);
 	else
 		FD_SET(c->sock, writeset);
 }
@@ -640,7 +632,7 @@ channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
 		break;
 	}
 	if (ret < 0) {
-		channel_free(c->self);
+		chan_mark_dead(c);
 	} else if (ret == 0) {
 		debug2("channel %d: pre_dynamic: need more", c->self);
 		/* need more */
@@ -656,8 +648,9 @@ channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
 void
 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
 {
+	Channel *nc;
 	struct sockaddr addr;
-	int newsock, newch, oldch;
+	int newsock;
 	socklen_t addrlen;
 	char buf[16384], *remote_ipaddr;
 	int remote_port;
@@ -675,16 +668,19 @@ channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
 		snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
 		    remote_ipaddr, remote_port);
 
-		oldch = c->self;
-		newch = channel_new("x11",
+		nc = channel_new("accepted x11 socket",
 		    SSH_CHANNEL_OPENING, newsock, newsock, -1,
 		    c->local_window_max, c->local_maxpacket,
 		    0, xstrdup(buf), 1);
-		c = channel_lookup(oldch);
+		if (nc == NULL) {
+			close(newsock);
+			xfree(remote_ipaddr);
+			return;
+		}
 		if (compat20) {
 			packet_start(SSH2_MSG_CHANNEL_OPEN);
 			packet_put_cstring("x11");
-			packet_put_int(newch);
+			packet_put_int(nc->self);
 			packet_put_int(c->local_window_max);
 			packet_put_int(c->local_maxpacket);
 			/* originator ipaddr and port */
@@ -697,7 +693,7 @@ channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
 			packet_send();
 		} else {
 			packet_start(SSH_SMSG_X11_OPEN);
-			packet_put_int(newch);
+			packet_put_int(nc->self);
 			if (have_hostname_in_open)
 				packet_put_string(buf, strlen(buf));
 			packet_send();
@@ -764,7 +760,7 @@ channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
 {
 	Channel *nc;
 	struct sockaddr addr;
-	int newsock, newch, nextstate, oldch;
+	int newsock, nextstate;
 	socklen_t addrlen;
 	char *rtype;
 
@@ -784,16 +780,13 @@ channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
 			error("accept: %.100s", strerror(errno));
 			return;
 		}
-		oldch = c->self;
-		newch = channel_new(rtype,
+		nc = channel_new(rtype,
 		    nextstate, newsock, newsock, -1,
 		    c->local_window_max, c->local_maxpacket,
 		    0, xstrdup(rtype), 1);
-
-		c = channel_lookup(oldch);
-		nc = channel_lookup(newch);
 		if (nc == NULL) {
-			error("xxx: no new channel:");
+			error("channel_post_port_listener: no new channel:");
+			close(newsock);
 			return;
 		}
 		nc->listening_port = c->listening_port;
@@ -812,8 +805,9 @@ channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
 void
 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
 {
+	Channel *nc;
+	int newsock;
 	struct sockaddr addr;
-	int newsock, newch, oldch;
 	socklen_t addrlen;
 
 	if (FD_ISSET(c->sock, readset)) {
@@ -823,21 +817,23 @@ channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
 			error("accept from auth socket: %.100s", strerror(errno));
 			return;
 		}
-		oldch = c->self;
-		newch = channel_new("accepted auth socket",
+		nc = channel_new("accepted auth socket",
 		    SSH_CHANNEL_OPENING, newsock, newsock, -1,
 		    c->local_window_max, c->local_maxpacket,
 		    0, xstrdup("accepted auth socket"), 1);
-		c = channel_lookup(oldch);
+		if (nc == NULL) {
+			error("channel_post_auth_listener: channel_new failed");
+			close(newsock);
+		}
 		if (compat20) {
 			packet_start(SSH2_MSG_CHANNEL_OPEN);
 			packet_put_cstring("auth-agent@openssh.com");
-			packet_put_int(newch);
+			packet_put_int(nc->self);
 			packet_put_int(c->local_window_max);
 			packet_put_int(c->local_maxpacket);
 		} else {
 			packet_start(SSH_SMSG_AGENT_OPEN);
-			packet_put_int(newch);
+			packet_put_int(nc->self);
 		}
 		packet_send();
 	}
@@ -881,7 +877,7 @@ channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
 			    c->self, c->rfd, len);
 			if (c->type != SSH_CHANNEL_OPEN) {
 				debug("channel %d: not open", c->self);
-				channel_free(c->self);
+				chan_mark_dead(c);
 				return -1;
 			} else if (compat13) {
 				buffer_consume(&c->output, buffer_len(&c->output));
@@ -920,7 +916,7 @@ channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
 		if (len <= 0) {
 			if (c->type != SSH_CHANNEL_OPEN) {
 				debug("channel %d: not open", c->self);
-				channel_free(c->self);
+				chan_mark_dead(c);
 				return -1;
 			} else if (compat13) {
 				buffer_consume(&c->output, buffer_len(&c->output));
@@ -1138,13 +1134,12 @@ channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
 		did_init = 1;
 	}
 	for (i = 0; i < channels_alloc; i++) {
-		c = &channels[i];
-		if (c->type == SSH_CHANNEL_FREE)
+		c = channels[i];
+		if (c == NULL)
 			continue;
 		if (ftab[c->type] == NULL)
 			continue;
 		(*ftab[c->type])(c, readset, writeset);
-		c = &channels[i]; /* XXX realloc */
 		if (chan_is_dead(c)) {
 			/*
 			 * we have to remove the fd's from the select mask
@@ -1161,7 +1156,7 @@ channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
 				if (c->extended_usage == CHAN_EXTENDED_WRITE)
 					FD_CLR(c->efd, writeset);
 			}
-			channel_free(c->self);
+			channel_free(c);
 		}
 	}
 }
@@ -1207,7 +1202,10 @@ channel_output_poll()
 	Channel *c;
 
 	for (i = 0; i < channels_alloc; i++) {
-		c = &channels[i];
+
+		c = channels[i];
+		if (c == NULL)
+			continue;
 
 		/* We are only interested in channels that can have buffered incoming data. */
 		if (compat13) {
@@ -1391,8 +1389,8 @@ channel_not_very_much_buffered_data()
 	Channel *c;
 
 	for (i = 0; i < channels_alloc; i++) {
-		c = &channels[i];
-		if (c->type == SSH_CHANNEL_OPEN) {
+		c = channels[i];
+		if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
 			if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
 				debug("channel %d: big input buffer %d",
 				    c->self, buffer_len(&c->input));
@@ -1486,7 +1484,7 @@ channel_input_close_confirmation(int type, int plen, void *ctxt)
 	if (c->type != SSH_CHANNEL_CLOSED)
 		packet_disconnect("Received close confirmation for "
 		    "non-closed channel %d (type %d).", id, c->type);
-	channel_free(c->self);
+	channel_free(c);
 }
 
 void
@@ -1554,7 +1552,7 @@ channel_input_open_failure(int type, int plen, void *ctxt)
 			xfree(lang);
 	}
 	/* Free the channel.  This will also close the socket. */
-	channel_free(id);
+	channel_free(c);
 }
 
 void
@@ -1615,21 +1613,26 @@ void
 channel_stop_listening()
 {
 	int i;
+	Channel *c;
+
 	for (i = 0; i < channels_alloc; i++) {
-		switch (channels[i].type) {
-		case SSH_CHANNEL_AUTH_SOCKET:
-			close(channels[i].sock);
-			unlink(channels[i].path);
-			channel_free(i);
-			break;
-		case SSH_CHANNEL_PORT_LISTENER:
-		case SSH_CHANNEL_RPORT_LISTENER:
-		case SSH_CHANNEL_X11_LISTENER:
-			close(channels[i].sock);
-			channel_free(i);
-			break;
-		default:
-			break;
+		c = channels[i];
+		if (c != NULL) {
+			switch (c->type) {
+			case SSH_CHANNEL_AUTH_SOCKET:
+				close(c->sock);
+				unlink(c->path);
+				channel_free(c);
+				break;
+			case SSH_CHANNEL_PORT_LISTENER:
+			case SSH_CHANNEL_RPORT_LISTENER:
+			case SSH_CHANNEL_X11_LISTENER:
+				close(c->sock);
+				channel_free(c);
+				break;
+			default:
+				break;
+			}
 		}
 	}
 }
@@ -1643,9 +1646,10 @@ void
 channel_close_all()
 {
 	int i;
+
 	for (i = 0; i < channels_alloc; i++)
-		if (channels[i].type != SSH_CHANNEL_FREE)
-			channel_close_fds(&channels[i]);
+		if (channels[i] != NULL)
+			channel_close_fds(channels[i]);
 }
 
 /* Returns true if any channel is still open. */
@@ -1653,10 +1657,14 @@ channel_close_all()
 int
 channel_still_open()
 {
-	u_int i;
-	for (i = 0; i < channels_alloc; i++)
-		switch (channels[i].type) {
-		case SSH_CHANNEL_FREE:
+	int i;
+	Channel *c;
+
+	for (i = 0; i < channels_alloc; i++) {
+		c = channels[i];
+		if (c == NULL)
+			continue;
+		switch (c->type) {
 		case SSH_CHANNEL_X11_LISTENER:
 		case SSH_CHANNEL_PORT_LISTENER:
 		case SSH_CHANNEL_RPORT_LISTENER:
@@ -1679,9 +1687,10 @@ channel_still_open()
 				fatal("cannot happen: OUT_DRAIN");
 			return 1;
 		default:
-			fatal("channel_still_open: bad channel type %d", channels[i].type);
+			fatal("channel_still_open: bad channel type %d", c->type);
 			/* NOTREACHED */
 		}
+	}
 	return 0;
 }
 
@@ -1690,12 +1699,16 @@ channel_still_open()
 int
 channel_find_open()
 {
-	u_int i;
-	for (i = 0; i < channels_alloc; i++)
-		switch (channels[i].type) {
+	int i;
+	Channel *c;
+
+	for (i = 0; i < channels_alloc; i++) {
+		c = channels[i];
+		if (c == NULL)
+			continue;
+		switch (c->type) {
 		case SSH_CHANNEL_CLOSED:
 		case SSH_CHANNEL_DYNAMIC:
-		case SSH_CHANNEL_FREE:
 		case SSH_CHANNEL_X11_LISTENER:
 		case SSH_CHANNEL_PORT_LISTENER:
 		case SSH_CHANNEL_RPORT_LISTENER:
@@ -1713,9 +1726,10 @@ channel_find_open()
 				fatal("cannot happen: OUT_DRAIN");
 			return i;
 		default:
-			fatal("channel_find_open: bad channel type %d", channels[i].type);
+			fatal("channel_find_open: bad channel type %d", c->type);
 			/* NOTREACHED */
 		}
+	}
 	return -1;
 }
 
@@ -1730,16 +1744,18 @@ char *
 channel_open_message()
 {
 	Buffer buffer;
+	Channel *c;
+	char buf[1024], *cp;
 	int i;
-	char buf[512], *cp;
 
 	buffer_init(&buffer);
 	snprintf(buf, sizeof buf, "The following connections are open:\r\n");
 	buffer_append(&buffer, buf, strlen(buf));
 	for (i = 0; i < channels_alloc; i++) {
-		Channel *c = &channels[i];
+		c = channels[i];
+		if (c == NULL)
+			continue;
 		switch (c->type) {
-		case SSH_CHANNEL_FREE:
 		case SSH_CHANNEL_X11_LISTENER:
 		case SSH_CHANNEL_PORT_LISTENER:
 		case SSH_CHANNEL_RPORT_LISTENER:
@@ -1797,7 +1813,8 @@ channel_request_forwarding(
     const char *host_to_connect, u_short port_to_connect,
     int gateway_ports, int remote_fwd)
 {
-	int success, ch, sock, on = 1, ctype;
+	Channel *c;
+	int success, sock, on = 1, ctype;
 	struct addrinfo hints, *ai, *aitop;
 	char ntop[NI_MAXHOST], strport[NI_MAXSERV];
 	const char *host;
@@ -1813,7 +1830,7 @@ channel_request_forwarding(
 		ctype  =SSH_CHANNEL_PORT_LISTENER;
 	}
 
-	if (strlen(host) > sizeof(channels[0].path) - 1) {
+	if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
 		error("Forward host name too long.");
 		return success;
 	}
@@ -1874,12 +1891,17 @@ channel_request_forwarding(
 			continue;
 		}
 		/* Allocate a channel number for the socket. */
-		ch = channel_new("port listener", ctype, sock, sock, -1,
+		c = channel_new("port listener", ctype, sock, sock, -1,
 		    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
 		    0, xstrdup("port listener"), 1);
-		strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
-		channels[ch].host_port = port_to_connect;
-		channels[ch].listening_port = listen_port;
+		if (c == NULL) {
+			error("channel_request_forwarding: channel_new failed");
+			close(sock);
+			continue;
+		}
+		strlcpy(c->path, host, sizeof(c->path));
+		c->host_port = port_to_connect;
+		c->listening_port = listen_port;
 		success = 1;
 	}
 	if (success == 0)
@@ -2116,11 +2138,12 @@ channel_connect_to(const char *host, u_short port)
 void
 channel_input_port_open(int type, int plen, void *ctxt)
 {
+	Channel *c = NULL;
 	u_short host_port;
 	char *host, *originator_string;
-	int remote_channel, sock = -1, newch;
+	int remote_id, sock = -1;
 
-	remote_channel = packet_get_int();
+	remote_id = packet_get_int();
 	host = packet_get_string(NULL);
 	host_port = packet_get_int();
 
@@ -2132,20 +2155,26 @@ channel_input_port_open(int type, int plen, void *ctxt)
 	packet_done();
 	sock = channel_connect_to(host, host_port);
 	if (sock != -1) {
-		newch = channel_allocate(SSH_CHANNEL_CONNECTING,
-		    sock, originator_string);
-		channels[newch].remote_id = remote_channel;
-
+		c = channel_new("connected socket",
+		    SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
+		    originator_string, 1);
+		if (c == NULL) {
+			error("channel_input_port_open: channel_new failed");
+			close(sock);
+		} else {
+			c->remote_id = remote_id;
+		}
+	}
+	if (c == NULL) {
+		packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
+		packet_put_int(remote_id);
+	} else {
 		/*XXX delay answer? */
 		packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
-		packet_put_int(remote_channel);
-		packet_put_int(newch);
-		packet_send();
-	} else {
-		packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
-		packet_put_int(remote_channel);
-		packet_send();
+		packet_put_int(remote_id);
+		packet_put_int(c->self);
 	}
+	packet_send();
 	xfree(host);
 }
 
@@ -2430,46 +2459,45 @@ x11_connect_display(void)
 void
 x11_input_open(int type, int plen, void *ctxt)
 {
-	int remote_channel, sock = 0, newch;
+	Channel *c = NULL;
+	int remote_id, sock = 0;
 	char *remote_host;
-	u_int remote_len;
 
-	/* Get remote channel number. */
-	remote_channel = packet_get_int();
+	debug("Received X11 open request.");
 
-	/* Get remote originator name. */
+	remote_id = packet_get_int();
 	if (have_hostname_in_open) {
-		remote_host = packet_get_string(&remote_len);
-		remote_len += 4;
+		remote_host = packet_get_string(NULL);
 	} else {
 		remote_host = xstrdup("unknown (remote did not supply name)");
-		remote_len = 0;
 	}
-
-	debug("Received X11 open request.");
-	packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
+	packet_done();
 
 	/* Obtain a connection to the real X display. */
 	sock = x11_connect_display();
-	if (sock == -1) {
+	if (sock != -1) {
+		/* Allocate a channel for this connection. */
+		c = channel_new("connected x11 socket",
+		    SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
+		    remote_host, 1);
+		if (c == NULL) {
+			error("x11_input_open: channel_new failed");
+			close(sock);
+		} else {
+			c->remote_id = remote_id;
+		}
+	}
+	if (c == NULL) {
 		/* Send refusal to the remote host. */
 		packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
-		packet_put_int(remote_channel);
-		packet_send();
+		packet_put_int(remote_id);
 	} else {
-		/* Allocate a channel for this connection. */
-		newch = channel_allocate(
-		     (x11_saved_proto == NULL) ?
-		     SSH_CHANNEL_OPEN : SSH_CHANNEL_X11_OPEN,
-		     sock, remote_host);
-		channels[newch].remote_id = remote_channel;
-
 		/* Send a confirmation to the remote host. */
 		packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
-		packet_put_int(remote_channel);
-		packet_put_int(newch);
-		packet_send();
+		packet_put_int(remote_id);
+		packet_put_int(c->self);
 	}
+	packet_send();
 }
 
 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
@@ -2602,7 +2630,8 @@ cleanup_socket(void)
 int
 auth_input_request_forwarding(struct passwd * pw)
 {
-	int sock, newch;
+	Channel *nc;
+	int sock;
 	struct sockaddr_un sunaddr;
 
 	if (auth_get_socket_name() != NULL)
@@ -2657,13 +2686,16 @@ auth_input_request_forwarding(struct passwd * pw)
 		packet_disconnect("listen: %.100s", strerror(errno));
 
 	/* Allocate a channel for the authentication agent socket. */
-	newch = channel_new("auth socket",
+	nc = channel_new("auth socket",
 	    SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
 	    CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
 	    0, xstrdup("auth socket"), 1);
-
-	strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
-	    sizeof(channels[newch].path));
+	if (nc == NULL) {
+		error("auth_input_request_forwarding: channel_new failed");
+		close(sock);
+		return 0;
+	}
+	strlcpy(nc->path, channel_forwarded_auth_socket_name, sizeof(nc->path));
 	return 1;
 }
 
@@ -2672,13 +2704,14 @@ auth_input_request_forwarding(struct passwd * pw)
 void
 auth_input_open_request(int type, int plen, void *ctxt)
 {
-	int remch, sock, newch;
+	Channel *c = NULL;
+	int remote_id, sock;
 	char *dummyname;
 
 	packet_integrity_check(plen, 4, type);
 
 	/* Read the remote channel number from the message. */
-	remch = packet_get_int();
+	remote_id = packet_get_int();
 
 	/*
 	 * Get a connection to the local authentication agent (this may again
@@ -2692,28 +2725,26 @@ auth_input_open_request(int type, int plen, void *ctxt)
 	 * because authentication forwarding is only enabled if we have an
 	 * agent.
 	 */
-	if (sock < 0) {
+	if (sock >= 0) {
+		dummyname = xstrdup("authentication agent connection");
+		c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, -1, 0, 0, 0, dummyname, 1);
+		if (c == NULL) {
+			error("auth_input_open_request: channel_new failed");
+			close(sock);
+		} else {
+			c->remote_id = remote_id;
+		}
+	}
+	if (c == NULL) {
 		packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
-		packet_put_int(remch);
-		packet_send();
-		return;
+		packet_put_int(remote_id);
+	} else {
+		/* Send a confirmation to the remote host. */
+		debug("Forwarding authentication connection.");
+		packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
+		packet_put_int(remote_id);
+		packet_put_int(c->self);
 	}
-	debug("Forwarding authentication connection.");
-
-	/*
-	 * Dummy host name.  This will be freed when the channel is freed; it
-	 * will still be valid in the packet_put_string below since the
-	 * channel cannot yet be freed at that point.
-	 */
-	dummyname = xstrdup("authentication agent connection");
-
-	newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
-	channels[newch].remote_id = remch;
-
-	/* Send a confirmation to the remote host. */
-	packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
-	packet_put_int(remch);
-	packet_put_int(newch);
 	packet_send();
 }
 
diff --git a/channels.h b/channels.h
index bf70a8f2..6739b221 100644
--- a/channels.h
+++ b/channels.h
@@ -32,7 +32,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-/* RCSID("$OpenBSD: channels.h,v 1.31 2001/04/13 22:46:53 beck Exp $"); */
+/* RCSID("$OpenBSD: channels.h,v 1.32 2001/05/04 23:47:33 markus Exp $"); */
 
 #ifndef CHANNELS_H
 #define CHANNELS_H
@@ -40,7 +40,6 @@
 #include "buffer.h"
 
 /* Definitions for channel types. */
-#define SSH_CHANNEL_FREE		0	/* This channel is free (unused). */
 #define SSH_CHANNEL_X11_LISTENER	1	/* Listening for inet X11 conn. */
 #define SSH_CHANNEL_PORT_LISTENER	2	/* Listening on a port. */
 #define SSH_CHANNEL_OPENING		3	/* waiting for confirmation */
@@ -56,8 +55,10 @@
 #define SSH_CHANNEL_DYNAMIC		13
 #define SSH_CHANNEL_MAX_TYPE		14
 
+#define SSH_CHANNEL_PATH_LEN		30
+
 /*
- * Data structure for channel data.  This is iniailized in channel_allocate
+ * Data structure for channel data.  This is initialized in channel_new
  * and cleared in channel_free.
  */
 struct Channel;
@@ -84,8 +85,8 @@ struct Channel {
 	Buffer  output;		/* data received over encrypted connection for
 				 * send on socket */
 	Buffer  extended;
-	char    path[200];	/* path for unix domain sockets, or host name
-				 * for forwards */
+	char    path[SSH_CHANNEL_PATH_LEN];
+		/* path for unix domain sockets, or host name for forwards */
 	int     listening_port;	/* port being listened for forwards */
 	int     host_port;	/* remote port to connect for forwards */
 	char   *remote_name;	/* remote hostname */
@@ -132,10 +133,6 @@ void	channel_register_filter(int id, channel_filter_fn *fn);
 void	channel_cancel_cleanup(int id);
 Channel	*channel_lookup(int id);
 
-int
-channel_new(char *ctype, int type, int rfd, int wfd, int efd,
-    int window, int maxpack, int extended_usage, char *remote_name,
-    int nonblock);
 void
 channel_set_fds(int id, int rfd, int wfd, int efd,
     int extusage, int nonblock);
@@ -162,10 +159,13 @@ void    channel_set_options(int hostname_in_open);
  * must have been allocated with xmalloc; this will free it when the channel
  * is freed.
  */
-int     channel_allocate(int type, int sock, char *remote_name);
+Channel *
+channel_new(char *ctype, int type, int rfd, int wfd, int efd,
+    int window, int maxpack, int extended_usage, char *remote_name,
+    int nonblock);
 
 /* Free the channel and close its socket. */
-void    channel_free(int channel);
+void    channel_free(Channel *c);
 
 /*
  * Allocate/update select bitmasks and add any bits relevant to channels in
diff --git a/clientloop.c b/clientloop.c
index d7618973..2bc5b54a 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -59,7 +59,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: clientloop.c,v 1.66 2001/04/29 19:16:52 markus Exp $");
+RCSID("$OpenBSD: clientloop.c,v 1.67 2001/05/04 23:47:34 markus Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -1027,7 +1027,7 @@ 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, newch;
+	int sock;
 
 	/* Get rest of the packet */
 	listen_address = packet_get_string(NULL);
@@ -1040,12 +1040,18 @@ client_request_forwarded_tcpip(const char *request_type, int rchan)
 	    listen_address, listen_port, originator_address, originator_port);
 
 	sock = channel_connect_by_listen_adress(listen_port);
-	if (sock >= 0) {
-		newch = channel_new("forwarded-tcpip",
-		    SSH_CHANNEL_CONNECTING, sock, sock, -1,
-		    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
-		    xstrdup(originator_address), 1);
-		c = channel_lookup(newch);
+	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,
+	    xstrdup(originator_address), 1);
+	if (c == NULL) {
+		error("client_request_forwarded_tcpip: channel_new failed");
+		close(sock);
 	}
 	xfree(originator_address);
 	xfree(listen_address);
@@ -1058,7 +1064,7 @@ client_request_x11(const char *request_type, int rchan)
 	Channel *c = NULL;
 	char *originator;
 	int originator_port;
-	int sock, newch;
+	int sock;
 
 	if (!options.forward_x11) {
 		error("Warning: ssh server tried X11 forwarding.");
@@ -1076,15 +1082,18 @@ client_request_x11(const char *request_type, int rchan)
 	/* XXX check permission */
 	debug("client_request_x11: request from %s %d", originator,
 	    originator_port);
+	xfree(originator);
 	sock = x11_connect_display();
-	if (sock >= 0) {
-		newch = channel_new("x11",
-		    SSH_CHANNEL_X11_OPEN, sock, sock, -1,
-		    CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0,
-		    xstrdup("x11"), 1);
-		c = channel_lookup(newch);
+	if (sock < 0)
+		return NULL;
+	c = channel_new("x11",
+	    SSH_CHANNEL_X11_OPEN, sock, sock, -1,
+	    CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0,
+	    xstrdup("x11"), 1);
+	if (c == NULL) {
+		error("client_request_x11: channel_new failed");
+		close(sock);
 	}
-	xfree(originator);
 	return c;
 }
 
@@ -1092,7 +1101,7 @@ Channel*
 client_request_agent(const char *request_type, int rchan)
 {
 	Channel *c = NULL;
-	int sock, newch;
+	int sock;
 
 	if (!options.forward_agent) {
 		error("Warning: ssh server tried agent forwarding.");
@@ -1100,12 +1109,15 @@ client_request_agent(const char *request_type, int rchan)
 		return NULL;
 	}
 	sock =  ssh_get_authentication_socket();
-	if (sock >= 0) {
-		newch = channel_new("authentication agent connection",
-		    SSH_CHANNEL_OPEN, sock, sock, -1,
-		    CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
-		    xstrdup("authentication agent connection"), 1);
-		c = channel_lookup(newch);
+	if (sock < 0)
+		return NULL;
+	c = channel_new("authentication agent connection",
+	    SSH_CHANNEL_OPEN, sock, sock, -1,
+	    CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
+	    xstrdup("authentication agent connection"), 1);
+	if (c == NULL) {
+		error("client_request_agent: channel_new failed");
+		close(sock);
 	}
 	return c;
 }
diff --git a/nchan.c b/nchan.c
index 77e4ef48..f4606e07 100644
--- a/nchan.c
+++ b/nchan.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: nchan.c,v 1.23 2001/02/28 08:54:55 markus Exp $");
+RCSID("$OpenBSD: nchan.c,v 1.24 2001/05/04 23:47:34 markus Exp $");
 
 #include "ssh1.h"
 #include "ssh2.h"
@@ -391,9 +391,17 @@ chan_send_close2(Channel *c)
 
 /* shared */
 
+void
+chan_mark_dead(Channel *c)
+{
+	c->flags |= CHAN_DEAD;
+}
+
 int
 chan_is_dead(Channel *c)
 {
+	if (c->flags & CHAN_DEAD)
+		return 1;
 	if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
 		return 0;
 	if (!compat20) {
diff --git a/nchan.h b/nchan.h
index 623ecccc..db04973f 100644
--- a/nchan.h
+++ b/nchan.h
@@ -22,7 +22,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-/* RCSID("$OpenBSD: nchan.h,v 1.10 2001/02/28 08:54:55 markus Exp $"); */
+/* RCSID("$OpenBSD: nchan.h,v 1.11 2001/05/04 23:47:34 markus Exp $"); */
 
 #ifndef NCHAN_H
 #define NCHAN_H
@@ -69,6 +69,7 @@
 
 #define CHAN_CLOSE_SENT			0x01
 #define CHAN_CLOSE_RCVD			0x02
+#define CHAN_DEAD			0x04
 
 
 /* Channel EVENTS */
@@ -85,6 +86,7 @@ extern chan_event_fn	*chan_write_failed;
 extern chan_event_fn	*chan_obuf_empty;
 
 int chan_is_dead(Channel * c);
+void chan_mark_dead(Channel * c);
 
 void    chan_init_iostates(Channel * c);
 void	chan_init(void);
diff --git a/serverloop.c b/serverloop.c
index 2ca892e5..5b313556 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -35,7 +35,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: serverloop.c,v 1.63 2001/04/29 19:16:52 markus Exp $");
+RCSID("$OpenBSD: serverloop.c,v 1.64 2001/05/04 23:47:34 markus Exp $");
 
 #include "xmalloc.h"
 #include "packet.h"
@@ -801,7 +801,8 @@ server_input_window_size(int type, int plen, void *ctxt)
 Channel *
 server_request_direct_tcpip(char *ctype)
 {
-	int sock, newch;
+	Channel *c;
+	int sock;
 	char *target, *originator;
 	int target_port, originator_port;
 
@@ -820,16 +821,20 @@ server_request_direct_tcpip(char *ctype)
 	xfree(originator);
 	if (sock < 0)
 		return NULL;
-	newch = channel_new(ctype, SSH_CHANNEL_CONNECTING,
+	c = channel_new(ctype, SSH_CHANNEL_CONNECTING,
 	    sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
 	    CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1);
-	return (newch >= 0) ? channel_lookup(newch) : NULL;
+	if (c == NULL) {
+		error("server_request_direct_tcpip: channel_new failed");
+		close(sock);
+	}
+	return c;
 }
 
 Channel *
 server_request_session(char *ctype)
 {
-	int newch;
+	Channel *c;
 
 	debug("input_session_request");
 	packet_done();
@@ -839,19 +844,22 @@ server_request_session(char *ctype)
 	 * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
 	 * CHANNEL_REQUEST messages is registered.
 	 */
-	newch = channel_new(ctype, SSH_CHANNEL_LARVAL,
-	    -1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT,
+	c = channel_new(ctype, SSH_CHANNEL_LARVAL,
+	    -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
 	    0, xstrdup("server-session"), 1);
-	if (session_open(newch) == 1) {
-		channel_register_callback(newch, SSH2_MSG_CHANNEL_REQUEST,
-		    session_input_channel_req, (void *)0);
-		channel_register_cleanup(newch, session_close_by_channel);
-		return channel_lookup(newch);
-	} else {
-		debug("session open failed, free channel %d", newch);
-		channel_free(newch);
+	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;
 	}
-	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;
 }
 
 void
diff --git a/ssh.c b/ssh.c
index 0ba69be5..c2932582 100644
--- a/ssh.c
+++ b/ssh.c
@@ -39,7 +39,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh.c,v 1.117 2001/04/30 11:18:52 markus Exp $");
+RCSID("$OpenBSD: ssh.c,v 1.118 2001/05/04 23:47:34 markus Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -1058,8 +1058,8 @@ ssh_session2_callback(int id, void *arg)
 int
 ssh_session2_command(void)
 {
-	int id, window, packetmax;
-	int in, out, err;
+	Channel *c;
+	int window, packetmax, in, out, err;
 
 	if (stdin_null_flag) {
 		in = open(_PATH_DEVNULL, O_RDONLY);
@@ -1086,18 +1086,20 @@ ssh_session2_command(void)
 		window *= 2;
 		packetmax *=2;
 	}
-	id = channel_new(
+	c = channel_new(
 	    "session", SSH_CHANNEL_OPENING, in, out, err,
 	    window, packetmax, CHAN_EXTENDED_WRITE,
 	    xstrdup("client-session"), /*nonblock*/0);
+	if (c == NULL)
+		fatal("ssh_session2_command: channel_new failed");
 
-debug("channel_new: %d", id);
+	debug3("ssh_session2_command: channel_new: %d", c->self);
 
-	channel_open(id);
-	channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
+	channel_open(c->self);
+	channel_register_callback(c->self, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
 	     ssh_session2_callback, (void *)0);
 
-	return id;
+	return c->self;
 }
 
 int