1 files changed, 682 insertions, 512 deletions

diff --git a/channels.c b/channels.c
index e60ecc614..b87ff9f4f 100644
--- a/channels.c
+++ b/channels.c
@@ -16,7 +16,7 @@
  */
 
 #include "includes.h"
-RCSID("$Id: channels.c,v 1.19 2000/03/17 12:40:15 damien Exp $");
+RCSID("$Id: channels.c,v 1.20 2000/04/01 01:09:23 damien Exp $");
 
 #include "ssh.h"
 #include "packet.h"
@@ -37,6 +37,10 @@ RCSID("$Id: channels.c,v 1.19 2000/03/17 12:40:15 damien Exp $");
 /* Max len of agent socket */
 #define MAX_SOCKET_NAME 100
 
+/* default buffer for tcp-fwd-channel */
+#define CHAN_WINDOW_DEFAULT      (8*1024)
+#define CHAN_PACKET_DEFAULT      (CHAN_WINDOW_DEFAULT/2)
+
 /*
  * Pointer to an array containing all allocated channels.  The array is
  * dynamically extended as needed.
@@ -81,8 +85,9 @@ unsigned int x11_fake_data_len;
  * network (which might be behind a firewall).
  */
 typedef struct {
-        char *host;             /* Host name. */
-        u_short port;           /* Port number. */
+        char *host_to_connect;          /* Connect to 'host'. */
+        u_short port_to_connect;        /* Connect to 'port'. */
+        u_short listen_port;            /* Remote side should listen port number. */
 } ForwardPermission;
 
 /* List of all permitted host/port pairs to connect. */
@@ -119,20 +124,43 @@ channel_permit_all_opens()
         all_opens_permitted = 1;
 }
 
+/* lookup channel by id */
+
+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) {
+                log("channel_lookup: %d: bad id: channel free", id);
+                return NULL;
+        }
+        return c;
+}
+
 /*
  * Allocate a new channel object and set its type and socket. This will cause
  * remote_name to be freed.
  */
 
 int 
-channel_allocate(int type, int sock, char *remote_name)
+channel_new(char *ctype, int type, int rfd, int wfd, int efd,
+    int window, int maxpack, int extended_usage, char *remote_name)
 {
         int i, found;
         Channel *c;
 
         /* Update the maximum file descriptor value. */
-        if (sock > channel_max_fd_value)
-                channel_max_fd_value = sock;
+        if (rfd > channel_max_fd_value)
+                channel_max_fd_value = rfd;
+        if (wfd > channel_max_fd_value)
+                channel_max_fd_value = wfd;
+        if (efd > channel_max_fd_value)
+                channel_max_fd_value = efd;
         /* XXX set close-on-exec -markus */
 
         /* Do initial allocation if this is the first call. */
@@ -167,388 +195,514 @@ channel_allocate(int type, int sock, char *remote_name)
         c = &channels[found];
         buffer_init(&c->input);
         buffer_init(&c->output);
+        buffer_init(&c->extended);
         chan_init_iostates(c);
         c->self = found;
         c->type = type;
-        c->sock = sock;
+        c->ctype = ctype;
+        c->local_window = window;
+        c->local_window_max = window;
+        c->local_consumed = 0;
+        c->local_maxpacket = maxpack;
+        c->remote_window = 0;
+        c->remote_maxpacket = 0;
+        c->rfd = rfd;
+        c->wfd = wfd;
+        c->sock = (rfd == wfd) ? rfd : -1;
+        c->efd = efd;
+        c->extended_usage = extended_usage;
         c->remote_id = -1;
         c->remote_name = remote_name;
+        c->remote_window = 0;
+        c->remote_maxpacket = 0;
+        c->cb_fn = NULL;
+        c->cb_arg = NULL;
+        c->cb_event = 0;
+        c->dettach_user = NULL;
         debug("channel %d: new [%s]", found, remote_name);
         return found;
 }
+int 
+channel_allocate(int type, int sock, char *remote_name)
+{
+        return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name);
+}
 
 /* Free the channel and close its socket. */
 
 void 
-channel_free(int channel)
+channel_free(int id)
 {
-        if (channel < 0 || channel >= channels_alloc ||
-            channels[channel].type == SSH_CHANNEL_FREE)
-                packet_disconnect("channel free: bad local channel %d", channel);
-
-        if (compat13)
-                shutdown(channels[channel].sock, SHUT_RDWR);
-        close(channels[channel].sock);
-        buffer_free(&channels[channel].input);
-        buffer_free(&channels[channel].output);
-        channels[channel].type = SSH_CHANNEL_FREE;
-        if (channels[channel].remote_name) {
-                xfree(channels[channel].remote_name);
-                channels[channel].remote_name = NULL;
+        Channel *c = channel_lookup(id);
+        if (c == NULL)
+                packet_disconnect("channel free: bad local channel %d", id);
+        debug("channel_free: channel %d: status: %s", id, channel_open_message());
+        if (c->sock != -1) {
+                shutdown(c->sock, SHUT_RDWR);
+                close(c->sock);
+        }
+        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;
         }
 }
 
 /*
- * This is called just before select() to add any bits relevant to channels
- * in the select bitmasks.
+ * 'channel_pre*' are called just before select() to add any bits relevant to
+ * channels in the select bitmasks.
+ */
+/*
+ * 'channel_post*': perform any appropriate operations for channels which
+ * have events pending.
  */
+typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
+chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
+chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
 
-void 
-channel_prepare_select(fd_set * readset, fd_set * writeset)
+void
+channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
 {
-        int i;
-        Channel *ch;
-        unsigned char *ucp;
-        unsigned int proto_len, data_len;
+        FD_SET(c->sock, readset);
+}
 
-        for (i = 0; i < channels_alloc; i++) {
-                ch = &channels[i];
-redo:
-                switch (ch->type) {
-                case SSH_CHANNEL_X11_LISTENER:
-                case SSH_CHANNEL_PORT_LISTENER:
-                case SSH_CHANNEL_AUTH_SOCKET:
-                        FD_SET(ch->sock, readset);
-                        break;
+void
+channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        if (buffer_len(&c->input) < packet_get_maxsize())
+                FD_SET(c->sock, readset);
+        if (buffer_len(&c->output) > 0)
+                FD_SET(c->sock, writeset);
+}
 
-                case SSH_CHANNEL_OPEN:
-                        if (compat13) {
-                                if (buffer_len(&ch->input) < packet_get_maxsize())
-                                        FD_SET(ch->sock, readset);
-                                if (buffer_len(&ch->output) > 0)
-                                        FD_SET(ch->sock, writeset);
-                                break;
-                        }
-                        /* test whether sockets are 'alive' for read/write */
-                        if (ch->istate == CHAN_INPUT_OPEN)
-                                if (buffer_len(&ch->input) < packet_get_maxsize())
-                                        FD_SET(ch->sock, readset);
-                        if (ch->ostate == CHAN_OUTPUT_OPEN ||
-                            ch->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
-                                if (buffer_len(&ch->output) > 0) {
-                                        FD_SET(ch->sock, writeset);
-                                } else if (ch->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
-                                        chan_obuf_empty(ch);
-                                }
-                        }
-                        break;
+void
+channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        /* test whether sockets are 'alive' for read/write */
+        if (c->istate == CHAN_INPUT_OPEN)
+                if (buffer_len(&c->input) < packet_get_maxsize())
+                        FD_SET(c->sock, readset);
+        if (c->ostate == CHAN_OUTPUT_OPEN ||
+            c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
+                if (buffer_len(&c->output) > 0) {
+                        FD_SET(c->sock, writeset);
+                } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
+                        chan_obuf_empty(c);
+                }
+        }
+}
 
-                case SSH_CHANNEL_INPUT_DRAINING:
-                        if (!compat13)
-                                fatal("cannot happen: IN_DRAIN");
-                        if (buffer_len(&ch->input) == 0) {
-                                packet_start(SSH_MSG_CHANNEL_CLOSE);
-                                packet_put_int(ch->remote_id);
-                                packet_send();
-                                ch->type = SSH_CHANNEL_CLOSED;
-                                debug("Closing channel %d after input drain.", ch->self);
-                                break;
-                        }
-                        break;
+void
+channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        if (buffer_len(&c->input) == 0) {
+                packet_start(SSH_MSG_CHANNEL_CLOSE);
+                packet_put_int(c->remote_id);
+                packet_send();
+                c->type = SSH_CHANNEL_CLOSED;
+                debug("Closing channel %d after input drain.", c->self);
+        }
+}
 
-                case SSH_CHANNEL_OUTPUT_DRAINING:
-                        if (!compat13)
-                                fatal("cannot happen: OUT_DRAIN");
-                        if (buffer_len(&ch->output) == 0) {
-                                channel_free(i);
-                                break;
-                        }
-                        FD_SET(ch->sock, writeset);
-                        break;
+void
+channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        if (buffer_len(&c->output) == 0)
+                channel_free(c->self);
+        else 
+                FD_SET(c->sock, writeset);
+}
 
-                case SSH_CHANNEL_X11_OPEN:
-                        /*
-                         * This is a special state for X11 authentication
-                         * spoofing.  An opened X11 connection (when
-                         * authentication spoofing is being done) remains in
-                         * this state until the first packet has been
-                         * completely read.  The authentication data in that
-                         * packet is then substituted by the real data if it
-                         * matches the fake data, and the channel is put into
-                         * normal mode.
-                         */
-                        /* Check if the fixed size part of the packet is in buffer. */
-                        if (buffer_len(&ch->output) < 12)
-                                break;
+/*
+ * This is a special state for X11 authentication spoofing.  An opened X11
+ * connection (when authentication spoofing is being done) remains in this
+ * state until the first packet has been completely read.  The authentication
+ * data in that packet is then substituted by the real data if it matches the
+ * fake data, and the channel is put into normal mode.
+ */
+int
+x11_open_helper(Channel *c)
+{
+        unsigned char *ucp;
+        unsigned int proto_len, data_len;
 
-                        /* Parse the lengths of variable-length fields. */
-                        ucp = (unsigned char *) buffer_ptr(&ch->output);
-                        if (ucp[0] == 0x42) {   /* Byte order MSB first. */
-                                proto_len = 256 * ucp[6] + ucp[7];
-                                data_len = 256 * ucp[8] + ucp[9];
-                        } else if (ucp[0] == 0x6c) {    /* Byte order LSB first. */
-                                proto_len = ucp[6] + 256 * ucp[7];
-                                data_len = ucp[8] + 256 * ucp[9];
-                        } else {
-                                debug("Initial X11 packet contains bad byte order byte: 0x%x",
-                                      ucp[0]);
-                                ch->type = SSH_CHANNEL_OPEN;
-                                goto reject;
-                        }
+        /* Check if the fixed size part of the packet is in buffer. */
+        if (buffer_len(&c->output) < 12)
+                return 0;
+
+        /* Parse the lengths of variable-length fields. */
+        ucp = (unsigned char *) buffer_ptr(&c->output);
+        if (ucp[0] == 0x42) {   /* Byte order MSB first. */
+                proto_len = 256 * ucp[6] + ucp[7];
+                data_len = 256 * ucp[8] + ucp[9];
+        } else if (ucp[0] == 0x6c) {    /* Byte order LSB first. */
+                proto_len = ucp[6] + 256 * ucp[7];
+                data_len = ucp[8] + 256 * ucp[9];
+        } else {
+                debug("Initial X11 packet contains bad byte order byte: 0x%x",
+                      ucp[0]);
+                return -1;
+        }
 
-                        /* Check if the whole packet is in buffer. */
-                        if (buffer_len(&ch->output) <
-                            12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
-                                break;
+        /* Check if the whole packet is in buffer. */
+        if (buffer_len(&c->output) <
+            12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
+                return 0;
 
-                        /* Check if authentication protocol matches. */
-                        if (proto_len != strlen(x11_saved_proto) ||
-                            memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
-                                debug("X11 connection uses different authentication protocol.");
-                                ch->type = SSH_CHANNEL_OPEN;
-                                goto reject;
-                        }
-                        /* Check if authentication data matches our fake data. */
-                        if (data_len != x11_fake_data_len ||
-                            memcmp(ucp + 12 + ((proto_len + 3) & ~3),
-                                x11_fake_data, x11_fake_data_len) != 0) {
-                                debug("X11 auth data does not match fake data.");
-                                ch->type = SSH_CHANNEL_OPEN;
-                                goto reject;
-                        }
-                        /* Check fake data length */
-                        if (x11_fake_data_len != x11_saved_data_len) {
-                                error("X11 fake_data_len %d != saved_data_len %d",
-                                  x11_fake_data_len, x11_saved_data_len);
-                                ch->type = SSH_CHANNEL_OPEN;
-                                goto reject;
-                        }
-                        /*
-                         * Received authentication protocol and data match
-                         * our fake data. Substitute the fake data with real
-                         * data.
-                         */
-                        memcpy(ucp + 12 + ((proto_len + 3) & ~3),
-                               x11_saved_data, x11_saved_data_len);
+        /* Check if authentication protocol matches. */
+        if (proto_len != strlen(x11_saved_proto) ||
+            memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
+                debug("X11 connection uses different authentication protocol.");
+                return -1;
+        }
+        /* Check if authentication data matches our fake data. */
+        if (data_len != x11_fake_data_len ||
+            memcmp(ucp + 12 + ((proto_len + 3) & ~3),
+                x11_fake_data, x11_fake_data_len) != 0) {
+                debug("X11 auth data does not match fake data.");
+                return -1;
+        }
+        /* Check fake data length */
+        if (x11_fake_data_len != x11_saved_data_len) {
+                error("X11 fake_data_len %d != saved_data_len %d",
+                    x11_fake_data_len, x11_saved_data_len);
+                return -1;
+        }
+        /*
+         * Received authentication protocol and data match
+         * our fake data. Substitute the fake data with real
+         * data.
+         */
+        memcpy(ucp + 12 + ((proto_len + 3) & ~3),
+            x11_saved_data, x11_saved_data_len);
+        return 1;
+}
 
-                        /* Start normal processing for the channel. */
-                        ch->type = SSH_CHANNEL_OPEN;
-                        goto redo;
+void
+channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        int ret = x11_open_helper(c);
+        if (ret == 1) {
+                /* Start normal processing for the channel. */
+                c->type = SSH_CHANNEL_OPEN;
+        } else if (ret == -1) {
+                /*
+                 * We have received an X11 connection that has bad
+                 * authentication information.
+                 */
+                log("X11 connection rejected because of wrong authentication.\r\n");
+                buffer_clear(&c->input);
+                buffer_clear(&c->output);
+                close(c->sock);
+                c->sock = -1;
+                c->type = SSH_CHANNEL_CLOSED;
+                packet_start(SSH_MSG_CHANNEL_CLOSE);
+                packet_put_int(c->remote_id);
+                packet_send();
+        }
+}
 
-        reject:
-                        /*
-                         * We have received an X11 connection that has bad
-                         * authentication information.
-                         */
-                        log("X11 connection rejected because of wrong authentication.\r\n");
-                        buffer_clear(&ch->input);
-                        buffer_clear(&ch->output);
-                        if (compat13) {
-                                close(ch->sock);
-                                ch->sock = -1;
-                                ch->type = SSH_CHANNEL_CLOSED;
-                                packet_start(SSH_MSG_CHANNEL_CLOSE);
-                                packet_put_int(ch->remote_id);
-                                packet_send();
-                        } else {
-                                debug("X11 rejected %d i%d/o%d", ch->self, ch->istate, ch->ostate);
-                                chan_read_failed(ch);
-                                chan_write_failed(ch);
-                                debug("X11 rejected %d i%d/o%d", ch->self, ch->istate, ch->ostate);
-                        }
-                        break;
+void
+channel_pre_x11_open_15(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        int ret = x11_open_helper(c);
+        if (ret == 1) {
+                c->type = SSH_CHANNEL_OPEN;
+        } else if (ret == -1) {
+                debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
+                chan_read_failed(c);
+                chan_write_failed(c);
+                debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
+        }
+}
 
-                case SSH_CHANNEL_FREE:
-                default:
-                        continue;
+/* This is our fake X11 server socket. */
+void
+channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        struct sockaddr addr;
+        int newsock, newch;
+        socklen_t addrlen;
+        char buf[16384], *remote_hostname;
+
+        if (FD_ISSET(c->sock, readset)) {
+                debug("X11 connection requested.");
+                addrlen = sizeof(addr);
+                newsock = accept(c->sock, &addr, &addrlen);
+                if (newsock < 0) {
+                        error("accept: %.100s", strerror(errno));
+                        return;
                 }
+                remote_hostname = get_remote_hostname(newsock);
+                snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
+                remote_hostname, get_peer_port(newsock));
+                xfree(remote_hostname);
+                newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
+                                         xstrdup(buf));
+                packet_start(SSH_SMSG_X11_OPEN);
+                packet_put_int(newch);
+                if (have_hostname_in_open)
+                        packet_put_string(buf, strlen(buf));
+                packet_send();
         }
 }
 
 /*
- * After select, perform any appropriate operations for channels which have
- * events pending.
+ * This socket is listening for connections to a forwarded TCP/IP port.
  */
+void
+channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        struct sockaddr addr;
+        int newsock, newch;
+        socklen_t addrlen;
+        char buf[1024], *remote_hostname;
+        int remote_port;
+
+        if (FD_ISSET(c->sock, readset)) {
+                debug("Connection to port %d forwarding "
+                    "to %.100s port %d requested.",
+                    c->listening_port, c->path, c->host_port);
+                addrlen = sizeof(addr);
+                newsock = accept(c->sock, &addr, &addrlen);
+                if (newsock < 0) {
+                        error("accept: %.100s", strerror(errno));
+                        return;
+                }
+                remote_hostname = get_remote_hostname(newsock);
+                remote_port = get_peer_port(newsock);
+                snprintf(buf, sizeof buf,
+                    "listen port %d for %.100s port %d, "
+                    "connect from %.200s port %d",
+                    c->listening_port, c->path, c->host_port,
+                    remote_hostname, remote_port);
+                newch = channel_new("direct-tcpip",
+                    SSH_CHANNEL_OPENING, newsock, newsock, -1,
+                    c->local_window_max, c->local_maxpacket,
+                    0, xstrdup(buf));
+
+                packet_start(SSH_MSG_PORT_OPEN);
+                packet_put_int(newch);
+                packet_put_string(c->path, strlen(c->path));
+                packet_put_int(c->host_port);
+                if (have_hostname_in_open) {
+                        packet_put_string(buf, strlen(buf));
+                }
+                packet_send();
+                xfree(remote_hostname);
+        }
+}
 
-void 
-channel_after_select(fd_set * readset, fd_set * writeset)
+/*
+ * This is the authentication agent socket listening for connections from
+ * clients.
+ */
+void
+channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
 {
         struct sockaddr addr;
-        int newsock, i, newch, len;
+        int newsock, newch;
         socklen_t addrlen;
-        Channel *ch;
-        char buf[16384], *remote_hostname;
 
-        /* Loop over all channels... */
-        for (i = 0; i < channels_alloc; i++) {
-                ch = &channels[i];
-                switch (ch->type) {
-                case SSH_CHANNEL_X11_LISTENER:
-                        /* This is our fake X11 server socket. */
-                        if (FD_ISSET(ch->sock, readset)) {
-                                debug("X11 connection requested.");
-                                addrlen = sizeof(addr);
-                                newsock = accept(ch->sock, &addr, &addrlen);
-                                if (newsock < 0) {
-                                        error("accept: %.100s", strerror(errno));
-                                        break;
-                                }
-                                remote_hostname = get_remote_hostname(newsock);
-                                snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
-                                remote_hostname, get_peer_port(newsock));
-                                xfree(remote_hostname);
-                                newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
-                                                         xstrdup(buf));
-                                packet_start(SSH_SMSG_X11_OPEN);
-                                packet_put_int(newch);
-                                if (have_hostname_in_open)
-                                        packet_put_string(buf, strlen(buf));
-                                packet_send();
-                        }
-                        break;
+        if (FD_ISSET(c->sock, readset)) {
+                addrlen = sizeof(addr);
+                newsock = accept(c->sock, &addr, &addrlen);
+                if (newsock < 0) {
+                        error("accept from auth socket: %.100s", strerror(errno));
+                        return;
+                }
+                newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
+                    xstrdup("accepted auth socket"));
+                packet_start(SSH_SMSG_AGENT_OPEN);
+                packet_put_int(newch);
+                packet_send();
+        }
+}
 
-                case SSH_CHANNEL_PORT_LISTENER:
-                        /*
-                         * This socket is listening for connections to a
-                         * forwarded TCP/IP port.
-                         */
-                        if (FD_ISSET(ch->sock, readset)) {
-                                debug("Connection to port %d forwarding to %.100s port %d requested.",
-                                      ch->listening_port, ch->path, ch->host_port);
-                                addrlen = sizeof(addr);
-                                newsock = accept(ch->sock, &addr, &addrlen);
-                                if (newsock < 0) {
-                                        error("accept: %.100s", strerror(errno));
-                                        break;
-                                }
-                                remote_hostname = get_remote_hostname(newsock);
-                                snprintf(buf, sizeof buf, "listen port %d for %.100s port %d, connect from %.200s port %d",
-                                         ch->listening_port, ch->path, ch->host_port,
-                                remote_hostname, get_peer_port(newsock));
-                                xfree(remote_hostname);
-                                newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
-                                                         xstrdup(buf));
-                                packet_start(SSH_MSG_PORT_OPEN);
-                                packet_put_int(newch);
-                                packet_put_string(ch->path, strlen(ch->path));
-                                packet_put_int(ch->host_port);
-                                if (have_hostname_in_open)
-                                        packet_put_string(buf, strlen(buf));
-                                packet_send();
+int
+channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        char buf[16*1024];
+        int len;
+
+        if (c->rfd != -1 &&
+            FD_ISSET(c->rfd, readset)) {
+                len = read(c->rfd, buf, sizeof(buf));
+                if (len <= 0) {
+                        debug("channel %d: read<0 rfd %d len %d",
+                            c->self, c->rfd, len);
+                        if (compat13) {
+                                buffer_consume(&c->output, buffer_len(&c->output));
+                                c->type = SSH_CHANNEL_INPUT_DRAINING;
+                                debug("Channel %d status set to input draining.", c->self);
+                        } else {
+                                chan_read_failed(c);
                         }
-                        break;
-
-                case SSH_CHANNEL_AUTH_SOCKET:
-                        /*
-                         * This is the authentication agent socket listening
-                         * for connections from clients.
-                         */
-                        if (FD_ISSET(ch->sock, readset)) {
-                                addrlen = sizeof(addr);
-                                newsock = accept(ch->sock, &addr, &addrlen);
-                                if (newsock < 0) {
-                                        error("accept from auth socket: %.100s", strerror(errno));
-                                        break;
-                                }
-                                newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
-                                        xstrdup("accepted auth socket"));
-                                packet_start(SSH_SMSG_AGENT_OPEN);
-                                packet_put_int(newch);
-                                packet_send();
+                        return -1;
+                }
+                buffer_append(&c->input, buf, len);
+        }
+        return 1;
+}
+int
+channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        int len;
+
+        /* Send buffered output data to the socket. */
+        if (c->wfd != -1 &&
+            FD_ISSET(c->wfd, writeset) &&
+            buffer_len(&c->output) > 0) {
+                len = write(c->wfd, buffer_ptr(&c->output),
+                            buffer_len(&c->output));
+                if (len <= 0) {
+                        if (compat13) {
+                                buffer_consume(&c->output, buffer_len(&c->output));
+                                debug("Channel %d status set to input draining.", c->self);
+                                c->type = SSH_CHANNEL_INPUT_DRAINING;
+                        } else {
+                                chan_write_failed(c);
                         }
-                        break;
+                        return -1;
+                }
+                buffer_consume(&c->output, len);
+        }
+        return 1;
+}
 
-                case SSH_CHANNEL_OPEN:
-                        /*
-                         * This is an open two-way communication channel. It
-                         * is not of interest to us at this point what kind
-                         * of data is being transmitted.
-                         */
+void
+channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        channel_handle_rfd(c, readset, writeset);
+        channel_handle_wfd(c, readset, writeset);
+}
 
-                        /*
-                         * Read available incoming data and append it to
-                         * buffer; shutdown socket, if read or write failes
-                         */
-                        if (FD_ISSET(ch->sock, readset)) {
-                                len = read(ch->sock, buf, sizeof(buf));
-                                if (len <= 0) {
-                                        if (compat13) {
-                                                buffer_consume(&ch->output, buffer_len(&ch->output));
-                                                ch->type = SSH_CHANNEL_INPUT_DRAINING;
-                                                debug("Channel %d status set to input draining.", i);
-                                        } else {
-                                                chan_read_failed(ch);
-                                        }
-                                        break;
-                                }
-                                buffer_append(&ch->input, buf, len);
-                        }
-                        /* Send buffered output data to the socket. */
-                        if (FD_ISSET(ch->sock, writeset) && buffer_len(&ch->output) > 0) {
-                                len = write(ch->sock, buffer_ptr(&ch->output),
-                                            buffer_len(&ch->output));
-                                if (len <= 0) {
-                                        if (compat13) {
-                                                buffer_consume(&ch->output, buffer_len(&ch->output));
-                                                debug("Channel %d status set to input draining.", i);
-                                                ch->type = SSH_CHANNEL_INPUT_DRAINING;
-                                        } else {
-                                                chan_write_failed(ch);
-                                        }
-                                        break;
-                                }
-                                buffer_consume(&ch->output, len);
-                        }
-                        break;
+void
+channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
+{
+        int len;
+        /* Send buffered output data to the socket. */
+        if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
+                len = write(c->sock, buffer_ptr(&c->output),
+                            buffer_len(&c->output));
+                if (len <= 0)
+                        buffer_consume(&c->output, buffer_len(&c->output));
+                else
+                        buffer_consume(&c->output, len);
+        }
+}
 
-                case SSH_CHANNEL_OUTPUT_DRAINING:
-                        if (!compat13)
-                                fatal("cannot happen: OUT_DRAIN");
-                        /* Send buffered output data to the socket. */
-                        if (FD_ISSET(ch->sock, writeset) && buffer_len(&ch->output) > 0) {
-                                len = write(ch->sock, buffer_ptr(&ch->output),
-                                            buffer_len(&ch->output));
-                                if (len <= 0)
-                                        buffer_consume(&ch->output, buffer_len(&ch->output));
-                                else
-                                        buffer_consume(&ch->output, len);
-                        }
-                        break;
+void
+channel_handler_init_13(void)
+{
+        channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open_13;
+        channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open_13;
+        channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
+        channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
+        channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
+        channel_pre[SSH_CHANNEL_INPUT_DRAINING] =       &channel_pre_input_draining;
+        channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] =      &channel_pre_output_draining;
+
+        channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open_1;
+        channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
+        channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
+        channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
+        channel_post[SSH_CHANNEL_OUTPUT_DRAINING] =     &channel_post_output_drain_13;
+}
 
-                case SSH_CHANNEL_X11_OPEN:
-                case SSH_CHANNEL_FREE:
-                default:
+void
+channel_handler_init_15(void)
+{
+        channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open_15;
+        channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open_15;
+        channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
+        channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
+        channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
+
+        channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
+        channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
+        channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
+        channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open_1;
+}
+
+void
+channel_handler_init(void)
+{
+        int i;
+        for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
+                channel_pre[i] = NULL;
+                channel_post[i] = NULL;
+        }
+        if (compat13)
+                channel_handler_init_13();
+        else
+                channel_handler_init_15();
+}
+
+void 
+channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
+{
+        static int did_init = 0;
+        int i;
+        Channel *c;
+
+        if (!did_init) {
+                channel_handler_init();
+                did_init = 1;
+        }
+        for (i = 0; i < channels_alloc; i++) {
+                c = &channels[i];
+                if (c->type == SSH_CHANNEL_FREE)
                         continue;
-                }
+                if (ftab[c->type] == NULL)
+                        continue;
+                (*ftab[c->type])(c, readset, writeset);
+                if (!compat13)
+                        chan_delete_if_full_closed(c);
         }
 }
 
+void 
+channel_prepare_select(fd_set * readset, fd_set * writeset)
+{
+        channel_handler(channel_pre, readset, writeset);
+}
+
+void 
+channel_after_select(fd_set * readset, fd_set * writeset)
+{
+        channel_handler(channel_post, readset, writeset);
+}
+
 /* If there is data to send to the connection, send some of it now. */
 
 void 
 channel_output_poll()
 {
         int len, i;
-        Channel *ch;
+        Channel *c;
 
         for (i = 0; i < channels_alloc; i++) {
-                ch = &channels[i];
+                c = &channels[i];
 
                 /* We are only interested in channels that can have buffered incoming data. */
                 if (compat13) {
-                        if (ch->type != SSH_CHANNEL_OPEN &&
-                            ch->type != SSH_CHANNEL_INPUT_DRAINING)
+                        if (c->type != SSH_CHANNEL_OPEN &&
+                            c->type != SSH_CHANNEL_INPUT_DRAINING)
                                 continue;
                 } else {
-                        if (ch->type != SSH_CHANNEL_OPEN)
+                        if (c->type != SSH_CHANNEL_OPEN)
                                 continue;
-                        if (ch->istate != CHAN_INPUT_OPEN &&
-                            ch->istate != CHAN_INPUT_WAIT_DRAIN)
+                        if (c->istate != CHAN_INPUT_OPEN &&
+                            c->istate != CHAN_INPUT_WAIT_DRAIN)
                                 continue;
                 }
 
                 /* Get the amount of buffered data for this channel. */
-                len = buffer_len(&ch->input);
+                len = buffer_len(&c->input);
                 if (len > 0) {
                         /* Send some data for the other side over the secure connection. */
                         if (packet_is_interactive()) {
@@ -556,22 +710,26 @@ channel_output_poll()
                                         len = 512;
                         } else {
                                 /* Keep the packets at reasonable size. */
-                                if (len > packet_get_maxsize()/2)
+                                if (len > packet_get_maxsize())
                                         len = packet_get_maxsize()/2;
                         }
-                        packet_start(SSH_MSG_CHANNEL_DATA);
-                        packet_put_int(ch->remote_id);
-                        packet_put_string(buffer_ptr(&ch->input), len);
-                        packet_send();
-                        buffer_consume(&ch->input, len);
-                } else if (ch->istate == CHAN_INPUT_WAIT_DRAIN) {
+                        if (len > 0) {
+                                packet_start(SSH_MSG_CHANNEL_DATA);
+                                packet_put_int(c->remote_id);
+                                packet_put_string(buffer_ptr(&c->input), len);
+                                packet_send();
+                                buffer_consume(&c->input, len);
+                                c->remote_window -= len;
+debug("channel %d: send data len %d", c->self, len);
+                        }
+                } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
                         if (compat13)
                                 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
                         /*
                          * input-buffer is empty and read-socket shutdown:
                          * tell peer, that we will not send more data: send IEOF
                          */
-                        chan_ibuf_empty(ch);
+                        chan_ibuf_empty(c);
                 }
         }
 }
@@ -583,35 +741,33 @@ channel_output_poll()
  */
 
 void 
-channel_input_data(int payload_len)
+channel_input_data(int type, int plen)
 {
         int id;
         char *data;
         unsigned int data_len;
-        Channel *ch;
+        Channel *c;
 
         /* Get the channel number and verify it. */
         id = packet_get_int();
-        if (id < 0 || id >= channels_alloc)
+        c = channel_lookup(id);
+        if (c == NULL)
                 packet_disconnect("Received data for nonexistent channel %d.", id);
-        ch = &channels[id];
-
-        if (ch->type == SSH_CHANNEL_FREE)
-                packet_disconnect("Received data for free channel %d.", ch->self);
 
         /* Ignore any data for non-open channels (might happen on close) */
-        if (ch->type != SSH_CHANNEL_OPEN &&
-            ch->type != SSH_CHANNEL_X11_OPEN)
+        if (c->type != SSH_CHANNEL_OPEN &&
+            c->type != SSH_CHANNEL_X11_OPEN)
                 return;
 
         /* same for protocol 1.5 if output end is no longer open */
-        if (!compat13 && ch->ostate != CHAN_OUTPUT_OPEN)
+        if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
                 return;
 
         /* Get the data. */
         data = packet_get_string(&data_len);
-        packet_integrity_check(payload_len, 4 + 4 + data_len, SSH_MSG_CHANNEL_DATA);
-        buffer_append(&ch->output, data, data_len);
+
+        packet_integrity_check(plen, 4 + 4 + data_len, SSH_MSG_CHANNEL_DATA);
+        buffer_append(&c->output, data, data_len);
         xfree(data);
 }
 
@@ -624,45 +780,60 @@ int
 channel_not_very_much_buffered_data()
 {
         unsigned int i;
-        Channel *ch;
+        Channel *c;
 
         for (i = 0; i < channels_alloc; i++) {
-                ch = &channels[i];
-                if (ch->type == SSH_CHANNEL_OPEN) {
-                        if (buffer_len(&ch->input) > packet_get_maxsize())
+                c = &channels[i];
+                if (c->type == SSH_CHANNEL_OPEN) {
+                        if (buffer_len(&c->input) > packet_get_maxsize()) {
+                                debug("channel %d: big input buffer %d",
+                                    c->self, buffer_len(&c->input));
                                 return 0;
-                        if (buffer_len(&ch->output) > packet_get_maxsize())
+                        }
+                        if (buffer_len(&c->output) > packet_get_maxsize()) {
+                                debug("channel %d: big output buffer %d",
+                                    c->self, buffer_len(&c->output));
                                 return 0;
+                        }
                 }
         }
         return 1;
 }
 
-/* This is called after receiving CHANNEL_CLOSE/IEOF. */
+void 
+channel_input_ieof(int type, int plen)
+{
+        int id;
+        Channel *c;
+
+        packet_integrity_check(plen, 4, type);
+
+        id = packet_get_int();
+        c = channel_lookup(id);
+        if (c == NULL)
+                packet_disconnect("Received ieof for nonexistent channel %d.", id);
+        chan_rcvd_ieof(c);
+}
 
 void 
-channel_input_close()
+channel_input_close(int type, int plen)
 {
-        int channel;
+        int id;
+        Channel *c;
 
-        /* Get the channel number and verify it. */
-        channel = packet_get_int();
-        if (channel < 0 || channel >= channels_alloc ||
-            channels[channel].type == SSH_CHANNEL_FREE)
-                packet_disconnect("Received data for nonexistent channel %d.", channel);
-
-        if (!compat13) {
-                /* proto version 1.5 overloads CLOSE with IEOF */
-                chan_rcvd_ieof(&channels[channel]);
-                return;
-        }
+        packet_integrity_check(plen, 4, type);
+
+        id = packet_get_int();
+        c = channel_lookup(id);
+        if (c == NULL)
+                packet_disconnect("Received close for nonexistent channel %d.", id);
 
         /*
          * Send a confirmation that we have closed the channel and no more
          * data is coming for it.
          */
         packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
-        packet_put_int(channels[channel].remote_id);
+        packet_put_int(c->remote_id);
         packet_send();
 
         /*
@@ -672,81 +843,80 @@ channel_input_close()
          * no-one to receive the confirmation.  The channel gets freed when
          * the confirmation arrives.
          */
-        if (channels[channel].type != SSH_CHANNEL_CLOSED) {
+        if (c->type != SSH_CHANNEL_CLOSED) {
                 /*
                  * Not a closed channel - mark it as draining, which will
                  * cause it to be freed later.
                  */
-                buffer_consume(&channels[channel].input,
-                               buffer_len(&channels[channel].input));
-                channels[channel].type = SSH_CHANNEL_OUTPUT_DRAINING;
+                buffer_consume(&c->input, buffer_len(&c->input));
+                c->type = SSH_CHANNEL_OUTPUT_DRAINING;
         }
 }
 
-/* This is called after receiving CHANNEL_CLOSE_CONFIRMATION/OCLOSE. */
-
+/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
 void 
-channel_input_close_confirmation()
+channel_input_oclose(int type, int plen)
 {
-        int channel;
-
-        /* Get the channel number and verify it. */
-        channel = packet_get_int();
-        if (channel < 0 || channel >= channels_alloc)
-                packet_disconnect("Received close confirmation for out-of-range channel %d.",
-                                  channel);
-
-        if (!compat13) {
-                /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
-                chan_rcvd_oclose(&channels[channel]);
-                return;
-        }
-        if (channels[channel].type != SSH_CHANNEL_CLOSED)
-                packet_disconnect("Received close confirmation for non-closed channel %d (type %d).",
-                                  channel, channels[channel].type);
-
-        /* Free the channel. */
-        channel_free(channel);
+        int id = packet_get_int();
+        Channel *c = channel_lookup(id);
+        packet_integrity_check(plen, 4, type);
+        if (c == NULL)
+                packet_disconnect("Received oclose for nonexistent channel %d.", id);
+        chan_rcvd_oclose(c);
 }
 
-/* This is called after receiving CHANNEL_OPEN_CONFIRMATION. */
+void 
+channel_input_close_confirmation(int type, int plen)
+{
+        int id = packet_get_int();
+        Channel *c = channel_lookup(id);
+
+        if (c == NULL)
+                packet_disconnect("Received close confirmation for "
+                    "out-of-range channel %d.", id);
+        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);
+}
 
 void 
-channel_input_open_confirmation()
+channel_input_open_confirmation(int type, int plen)
 {
-        int channel, remote_channel;
+        int id, remote_id;
+        Channel *c;
 
-        /* Get the channel number and verify it. */
-        channel = packet_get_int();
-        if (channel < 0 || channel >= channels_alloc ||
-            channels[channel].type != SSH_CHANNEL_OPENING)
-                packet_disconnect("Received open confirmation for non-opening channel %d.",
-                                  channel);
+        packet_integrity_check(plen, 4 + 4, type);
 
-        /* Get remote side's id for this channel. */
-        remote_channel = packet_get_int();
+        id = packet_get_int();
+        c = channel_lookup(id);
 
+        if (c==NULL || c->type != SSH_CHANNEL_OPENING)
+                packet_disconnect("Received open confirmation for "
+                    "non-opening channel %d.", id);
+        remote_id = packet_get_int();
         /* Record the remote channel number and mark that the channel is now open. */
-        channels[channel].remote_id = remote_channel;
-        channels[channel].type = SSH_CHANNEL_OPEN;
+        c->remote_id = remote_id;
+        c->type = SSH_CHANNEL_OPEN;
 }
 
-/* This is called after receiving CHANNEL_OPEN_FAILURE from the other side. */
-
 void 
-channel_input_open_failure()
+channel_input_open_failure(int type, int plen)
 {
-        int channel;
+        int id;
+        Channel *c;
 
-        /* Get the channel number and verify it. */
-        channel = packet_get_int();
-        if (channel < 0 || channel >= channels_alloc ||
-            channels[channel].type != SSH_CHANNEL_OPENING)
-                packet_disconnect("Received open failure for non-opening channel %d.",
-                                  channel);
+        packet_integrity_check(plen, 4, type);
+
+        id = packet_get_int();
+        c = channel_lookup(id);
+
+        if (c==NULL || c->type != SSH_CHANNEL_OPENING)
+                packet_disconnect("Received open failure for "
+                    "non-opening channel %d.", id);
 
         /* Free the channel.  This will also close the socket. */
-        channel_free(channel);
+        channel_free(id);
 }
 
 /*
@@ -859,15 +1029,16 @@ channel_open_message()
                 case SSH_CHANNEL_X11_OPEN:
                 case SSH_CHANNEL_INPUT_DRAINING:
                 case SSH_CHANNEL_OUTPUT_DRAINING:
-                        snprintf(buf, sizeof buf, "  #%d %.300s (t%d r%d i%d/%d o%d/%d)\r\n",
+                        snprintf(buf, sizeof buf, "  #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
                             c->self, c->remote_name,
                             c->type, c->remote_id,
                             c->istate, buffer_len(&c->input),
-                            c->ostate, buffer_len(&c->output));
+                            c->ostate, buffer_len(&c->output),
+                            c->rfd, c->wfd);
                         buffer_append(&buffer, buf, strlen(buf));
                         continue;
                 default:
-                        fatal("channel_still_open: bad channel type %d", c->type);
+                        fatal("channel_open_message: bad channel type %d", c->type);
                         /* NOTREACHED */
                 }
         }
@@ -950,8 +1121,11 @@ channel_request_local_forwarding(u_short port, const char *host,
                         continue;
                 }
                 /* Allocate a channel number for the socket. */
-                ch = channel_allocate(SSH_CHANNEL_PORT_LISTENER, sock,
-                    xstrdup("port listener"));
+                ch = channel_new(
+                    "port listener", SSH_CHANNEL_PORT_LISTENER,
+                    sock, sock, -1,
+                    CHAN_WINDOW_DEFAULT, CHAN_PACKET_DEFAULT,
+                    0, xstrdup("port listener"));
                 strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
                 channels[ch].host_port = host_port;
                 channels[ch].listening_port = port;
@@ -968,26 +1142,26 @@ channel_request_local_forwarding(u_short port, const char *host,
  */
 
 void 
-channel_request_remote_forwarding(u_short port, const char *host,
-                                  u_short remote_port)
+channel_request_remote_forwarding(u_short listen_port, const char *host_to_connect,
+                                  u_short port_to_connect)
 {
         int payload_len;
         /* Record locally that connection to this host/port is permitted. */
         if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
                 fatal("channel_request_remote_forwarding: too many forwards");
 
-        permitted_opens[num_permitted_opens].host = xstrdup(host);
-        permitted_opens[num_permitted_opens].port = remote_port;
+        permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
+        permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
+        permitted_opens[num_permitted_opens].listen_port = listen_port;
         num_permitted_opens++;
 
         /* Send the forward request to the remote side. */
         packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
-        packet_put_int(port);
-        packet_put_string(host, strlen(host));
-        packet_put_int(remote_port);
+        packet_put_int(port_to_connect);
+        packet_put_string(host_to_connect, strlen(host_to_connect));
+        packet_put_int(listen_port);
         packet_send();
         packet_write_wait();
-
         /*
          * Wait for response from the remote side.  It will send a disconnect
          * message on failure, and we will never see it here.
@@ -1029,63 +1203,14 @@ channel_input_port_forward_request(int is_root)
         xfree(hostname);
 }
 
-/*
- * This is called after receiving PORT_OPEN message.  This attempts to
- * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
- * or CHANNEL_OPEN_FAILURE.
- */
-
-void 
-channel_input_port_open(int payload_len)
+/* XXX move to aux.c */
+int
+channel_connect_to(const char *host, u_short host_port)
 {
-        int remote_channel, sock = 0, newch, i;
-        u_short host_port;
-        char *host, *originator_string;
-        unsigned int host_len, originator_len;
         struct addrinfo hints, *ai, *aitop;
         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
         int gaierr;
-
-        /* Get remote channel number. */
-        remote_channel = packet_get_int();
-
-        /* Get host name to connect to. */
-        host = packet_get_string(&host_len);
-
-        /* Get port to connect to. */
-        host_port = packet_get_int();
-
-        /* Get remote originator name. */
-        if (have_hostname_in_open) {
-                originator_string = packet_get_string(&originator_len);
-                originator_len += 4;    /* size of packet_int */
-        } else {
-                originator_string = xstrdup("unknown (remote did not supply name)");
-                originator_len = 0;     /* no originator supplied */
-        }
-
-        packet_integrity_check(payload_len,
-                               4 + 4 + host_len + 4 + originator_len,
-                               SSH_MSG_PORT_OPEN);
-
-        /* Check if opening that port is permitted. */
-        if (!all_opens_permitted) {
-                /* Go trough all permitted ports. */
-                for (i = 0; i < num_permitted_opens; i++)
-                        if (permitted_opens[i].port == host_port &&
-                            strcmp(permitted_opens[i].host, host) == 0)
-                                break;
-
-                /* Check if we found the requested port among those permitted. */
-                if (i >= num_permitted_opens) {
-                        /* The port is not permitted. */
-                        log("Received request to connect to %.100s:%d, but the request was denied.",
-                            host, host_port);
-                        packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
-                        packet_put_int(remote_channel);
-                        packet_send();
-                }
-        }
+        int sock = -1;
 
         memset(&hints, 0, sizeof(hints));
         hints.ai_family = IPv4or6;
@@ -1093,15 +1218,14 @@ channel_input_port_open(int payload_len)
         snprintf(strport, sizeof strport, "%d", host_port);
         if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
                 error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
-                goto fail;
+                return -1;
         }
-
         for (ai = aitop; ai; ai = ai->ai_next) {
                 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
                         continue;
                 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
                     strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
-                        error("channel_input_port_open: getnameinfo failed");
+                        error("channel_connect_to: getnameinfo failed");
                         continue;
                 }
                 /* Create the socket. */
@@ -1121,37 +1245,82 @@ channel_input_port_open(int payload_len)
 
         }
         freeaddrinfo(aitop);
-
         if (!ai) {
                 error("connect %.100s port %d: failed.", host, host_port);      
-                goto fail;
+                return -1;
         }
+        /* success */
+        return sock;
+}
 
-        /* Successful connection. */
+/*
+ * This is called after receiving PORT_OPEN message.  This attempts to
+ * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
+ * or CHANNEL_OPEN_FAILURE.
+ */
 
-        /* Allocate a channel for this connection. */
-        newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
-        channels[newch].remote_id = remote_channel;
+void 
+channel_input_port_open(int type, int plen)
+{
+        u_short host_port;
+        char *host, *originator_string;
+        int remote_channel, sock = -1, newch, i, denied;
+        unsigned int host_len, originator_len;
 
-        /* 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();
+        /* Get remote channel number. */
+        remote_channel = packet_get_int();
 
-        /* Free the argument string. */
-        xfree(host);
+        /* Get host name to connect to. */
+        host = packet_get_string(&host_len);
 
-        return;
+        /* Get port to connect to. */
+        host_port = packet_get_int();
 
-fail:
-        /* Free the argument string. */
-        xfree(host);
+        /* Get remote originator name. */
+        if (have_hostname_in_open) {
+                originator_string = packet_get_string(&originator_len);
+                originator_len += 4;    /* size of packet_int */
+        } else {
+                originator_string = xstrdup("unknown (remote did not supply name)");
+                originator_len = 0;     /* no originator supplied */
+        }
 
-        /* Send refusal to the remote host. */
-        packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
-        packet_put_int(remote_channel);
-        packet_send();
+        packet_integrity_check(plen,
+            4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN);
+
+        /* Check if opening that port is permitted. */
+        denied = 0;
+        if (!all_opens_permitted) {
+                /* Go trough all permitted ports. */
+                for (i = 0; i < num_permitted_opens; i++)
+                        if (permitted_opens[i].port_to_connect == host_port &&
+                            strcmp(permitted_opens[i].host_to_connect, host) == 0)
+                                break;
+
+                /* Check if we found the requested port among those permitted. */
+                if (i >= num_permitted_opens) {
+                        /* The port is not permitted. */
+                        log("Received request to connect to %.100s:%d, but the request was denied.",
+                            host, host_port);
+                        denied = 1;
+                }
+        }
+        sock = denied ? -1 : channel_connect_to(host, host_port);
+        if (sock > 0) {
+                /* Allocate a channel for this connection. */
+                newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
+                channels[newch].remote_id = remote_channel;
+
+                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();
+        }
+        xfree(host);
 }
 
 /*
@@ -1336,7 +1505,7 @@ connect_local_xsocket(unsigned int dnr)
  */
 
 void 
-x11_input_open(int payload_len)
+x11_input_open(int type, int plen)
 {
         int remote_channel, display_number, sock = 0, newch;
         const char *display;
@@ -1359,7 +1528,7 @@ x11_input_open(int payload_len)
         }
 
         debug("Received X11 open request.");
-        packet_integrity_check(payload_len, 4 + remote_len, SSH_SMSG_X11_OPEN);
+        packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
 
         /* Try to open a socket for the local X server. */
         display = getenv("DISPLAY");
@@ -1425,19 +1594,18 @@ x11_input_open(int payload_len)
                 sock = socket(ai->ai_family, SOCK_STREAM, 0);
                 if (sock < 0) {
                         debug("socket: %.100s", strerror(errno));
-                continue;
-        }
-        /* Connect it to the display. */
-        if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
-                debug("connect %.100s port %d: %.100s", buf, 6000 + display_number, 
-                    strerror(errno));
-                close(sock);
-                continue;
+                        continue;
+                }
+                /* Connect it to the display. */
+                if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
+                        debug("connect %.100s port %d: %.100s", buf,
+                            6000 + display_number, strerror(errno));
+                        close(sock);
+                        continue;
+                }
+                /* Success */
+                break;
         }
-        /* Success */
-        break;
-
-        } /* (ai = aitop, ai; ai = ai->ai_next) */
         freeaddrinfo(aitop);
         if (!ai) {
                 error("connect %.100s port %d: %.100s", buf, 6000 + display_number, 
@@ -1625,11 +1793,13 @@ auth_input_request_forwarding(struct passwd * pw)
 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
 
 void 
-auth_input_open_request()
+auth_input_open_request(int type, int plen)
 {
         int remch, sock, newch;
         char *dummyname;
 
+        packet_integrity_check(plen, 4, type);
+
         /* Read the remote channel number from the message. */
         remch = packet_get_int();