| /* |
| * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "includes.h" |
| RCSID("$OpenBSD: nchan.c,v 1.34 2002/01/09 17:26:35 markus Exp $"); |
| |
| #include "ssh1.h" |
| #include "ssh2.h" |
| #include "buffer.h" |
| #include "packet.h" |
| #include "channels.h" |
| #include "compat.h" |
| #include "log.h" |
| |
| /* |
| * SSH Protocol 1.5 aka New Channel Protocol |
| * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored. |
| * Written by Markus Friedl in October 1999 |
| * |
| * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the |
| * tear down of channels: |
| * |
| * 1.3: strict request-ack-protocol: |
| * CLOSE -> |
| * <- CLOSE_CONFIRM |
| * |
| * 1.5: uses variations of: |
| * IEOF -> |
| * <- OCLOSE |
| * <- IEOF |
| * OCLOSE -> |
| * i.e. both sides have to close the channel |
| * |
| * 2.0: the EOF messages are optional |
| * |
| * See the debugging output from 'ssh -v' and 'sshd -d' of |
| * ssh-1.2.27 as an example. |
| * |
| */ |
| |
| /* functions manipulating channel states */ |
| /* |
| * EVENTS update channel input/output states execute ACTIONS |
| */ |
| /* events concerning the INPUT from socket for channel (istate) */ |
| chan_event_fn *chan_rcvd_oclose = NULL; |
| chan_event_fn *chan_read_failed = NULL; |
| chan_event_fn *chan_ibuf_empty = NULL; |
| /* events concerning the OUTPUT from channel for socket (ostate) */ |
| chan_event_fn *chan_rcvd_ieof = NULL; |
| chan_event_fn *chan_write_failed = NULL; |
| chan_event_fn *chan_obuf_empty = NULL; |
| /* |
| * ACTIONS: should never update the channel states |
| */ |
| static void chan_send_ieof1(Channel *); |
| static void chan_send_oclose1(Channel *); |
| static void chan_send_close2(Channel *); |
| static void chan_send_eof2(Channel *); |
| |
| /* helper */ |
| static void chan_shutdown_write(Channel *); |
| static void chan_shutdown_read(Channel *); |
| |
| /* |
| * SSH1 specific implementation of event functions |
| */ |
| |
| static void |
| chan_rcvd_oclose1(Channel *c) |
| { |
| debug("channel %d: rcvd oclose", c->self); |
| switch (c->istate) { |
| case CHAN_INPUT_WAIT_OCLOSE: |
| debug("channel %d: input wait_oclose -> closed", c->self); |
| c->istate = CHAN_INPUT_CLOSED; |
| break; |
| case CHAN_INPUT_OPEN: |
| debug("channel %d: input open -> closed", c->self); |
| chan_shutdown_read(c); |
| chan_send_ieof1(c); |
| c->istate = CHAN_INPUT_CLOSED; |
| break; |
| case CHAN_INPUT_WAIT_DRAIN: |
| /* both local read_failed and remote write_failed */ |
| log("channel %d: input drain -> closed", c->self); |
| chan_send_ieof1(c); |
| c->istate = CHAN_INPUT_CLOSED; |
| break; |
| default: |
| error("channel %d: protocol error: rcvd_oclose for istate %d", |
| c->self, c->istate); |
| return; |
| } |
| } |
| static void |
| chan_read_failed_12(Channel *c) |
| { |
| debug("channel %d: read failed", c->self); |
| switch (c->istate) { |
| case CHAN_INPUT_OPEN: |
| debug("channel %d: input open -> drain", c->self); |
| chan_shutdown_read(c); |
| c->istate = CHAN_INPUT_WAIT_DRAIN; |
| #if 0 |
| if (buffer_len(&c->input) == 0) { |
| debug("channel %d: input: no drain shortcut", c->self); |
| chan_ibuf_empty(c); |
| } |
| #endif |
| break; |
| default: |
| error("channel %d: chan_read_failed for istate %d", |
| c->self, c->istate); |
| break; |
| } |
| } |
| static void |
| chan_ibuf_empty1(Channel *c) |
| { |
| debug("channel %d: ibuf empty", c->self); |
| if (buffer_len(&c->input)) { |
| error("channel %d: chan_ibuf_empty for non empty buffer", |
| c->self); |
| return; |
| } |
| switch (c->istate) { |
| case CHAN_INPUT_WAIT_DRAIN: |
| debug("channel %d: input drain -> wait_oclose", c->self); |
| chan_send_ieof1(c); |
| c->istate = CHAN_INPUT_WAIT_OCLOSE; |
| break; |
| default: |
| error("channel %d: chan_ibuf_empty for istate %d", |
| c->self, c->istate); |
| break; |
| } |
| } |
| static void |
| chan_rcvd_ieof1(Channel *c) |
| { |
| debug("channel %d: rcvd ieof", c->self); |
| if (c->type != SSH_CHANNEL_OPEN) { |
| debug("channel %d: non-open", c->self); |
| if (c->istate == CHAN_INPUT_OPEN) { |
| debug("channel %d: non-open: input open -> wait_oclose", |
| c->self); |
| chan_shutdown_read(c); |
| chan_send_ieof1(c); |
| c->istate = CHAN_INPUT_WAIT_OCLOSE; |
| } else { |
| error("channel %d: non-open: istate %d != open", |
| c->self, c->istate); |
| } |
| if (c->ostate == CHAN_OUTPUT_OPEN) { |
| debug("channel %d: non-open: output open -> closed", |
| c->self); |
| chan_send_oclose1(c); |
| c->ostate = CHAN_OUTPUT_CLOSED; |
| } else { |
| error("channel %d: non-open: ostate %d != open", |
| c->self, c->ostate); |
| } |
| return; |
| } |
| switch (c->ostate) { |
| case CHAN_OUTPUT_OPEN: |
| debug("channel %d: output open -> drain", c->self); |
| c->ostate = CHAN_OUTPUT_WAIT_DRAIN; |
| break; |
| case CHAN_OUTPUT_WAIT_IEOF: |
| debug("channel %d: output wait_ieof -> closed", c->self); |
| c->ostate = CHAN_OUTPUT_CLOSED; |
| break; |
| default: |
| error("channel %d: protocol error: rcvd_ieof for ostate %d", |
| c->self, c->ostate); |
| break; |
| } |
| } |
| static void |
| chan_write_failed1(Channel *c) |
| { |
| debug("channel %d: write failed", c->self); |
| switch (c->ostate) { |
| case CHAN_OUTPUT_OPEN: |
| debug("channel %d: output open -> wait_ieof", c->self); |
| chan_send_oclose1(c); |
| c->ostate = CHAN_OUTPUT_WAIT_IEOF; |
| break; |
| case CHAN_OUTPUT_WAIT_DRAIN: |
| debug("channel %d: output wait_drain -> closed", c->self); |
| chan_send_oclose1(c); |
| c->ostate = CHAN_OUTPUT_CLOSED; |
| break; |
| default: |
| error("channel %d: chan_write_failed for ostate %d", |
| c->self, c->ostate); |
| break; |
| } |
| } |
| static void |
| chan_obuf_empty1(Channel *c) |
| { |
| debug("channel %d: obuf empty", c->self); |
| if (buffer_len(&c->output)) { |
| error("channel %d: chan_obuf_empty for non empty buffer", |
| c->self); |
| return; |
| } |
| switch (c->ostate) { |
| case CHAN_OUTPUT_WAIT_DRAIN: |
| debug("channel %d: output drain -> closed", c->self); |
| chan_send_oclose1(c); |
| c->ostate = CHAN_OUTPUT_CLOSED; |
| break; |
| default: |
| error("channel %d: internal error: obuf_empty for ostate %d", |
| c->self, c->ostate); |
| break; |
| } |
| } |
| static void |
| chan_send_ieof1(Channel *c) |
| { |
| debug("channel %d: send ieof", c->self); |
| switch (c->istate) { |
| case CHAN_INPUT_OPEN: |
| case CHAN_INPUT_WAIT_DRAIN: |
| packet_start(SSH_MSG_CHANNEL_INPUT_EOF); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| break; |
| default: |
| error("channel %d: cannot send ieof for istate %d", |
| c->self, c->istate); |
| break; |
| } |
| } |
| static void |
| chan_send_oclose1(Channel *c) |
| { |
| debug("channel %d: send oclose", c->self); |
| switch (c->ostate) { |
| case CHAN_OUTPUT_OPEN: |
| case CHAN_OUTPUT_WAIT_DRAIN: |
| chan_shutdown_write(c); |
| buffer_clear(&c->output); |
| packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| break; |
| default: |
| error("channel %d: cannot send oclose for ostate %d", |
| c->self, c->ostate); |
| break; |
| } |
| } |
| |
| /* |
| * the same for SSH2 |
| */ |
| static void |
| chan_rcvd_oclose2(Channel *c) |
| { |
| debug("channel %d: rcvd close", c->self); |
| if (c->flags & CHAN_CLOSE_RCVD) |
| error("channel %d: protocol error: close rcvd twice", c->self); |
| c->flags |= CHAN_CLOSE_RCVD; |
| if (c->type == SSH_CHANNEL_LARVAL) { |
| /* tear down larval channels immediately */ |
| c->ostate = CHAN_OUTPUT_CLOSED; |
| c->istate = CHAN_INPUT_CLOSED; |
| return; |
| } |
| switch (c->ostate) { |
| case CHAN_OUTPUT_OPEN: |
| /* |
| * wait until a data from the channel is consumed if a CLOSE |
| * is received |
| */ |
| debug("channel %d: output open -> drain", c->self); |
| c->ostate = CHAN_OUTPUT_WAIT_DRAIN; |
| break; |
| } |
| switch (c->istate) { |
| case CHAN_INPUT_OPEN: |
| debug("channel %d: input open -> closed", c->self); |
| chan_shutdown_read(c); |
| break; |
| case CHAN_INPUT_WAIT_DRAIN: |
| debug("channel %d: input drain -> closed", c->self); |
| chan_send_eof2(c); |
| break; |
| } |
| c->istate = CHAN_INPUT_CLOSED; |
| } |
| static void |
| chan_ibuf_empty2(Channel *c) |
| { |
| debug("channel %d: ibuf empty", c->self); |
| if (buffer_len(&c->input)) { |
| error("channel %d: chan_ibuf_empty for non empty buffer", |
| c->self); |
| return; |
| } |
| switch (c->istate) { |
| case CHAN_INPUT_WAIT_DRAIN: |
| debug("channel %d: input drain -> closed", c->self); |
| if (!(c->flags & CHAN_CLOSE_SENT)) |
| chan_send_eof2(c); |
| c->istate = CHAN_INPUT_CLOSED; |
| break; |
| default: |
| error("channel %d: chan_ibuf_empty for istate %d", |
| c->self, c->istate); |
| break; |
| } |
| } |
| static void |
| chan_rcvd_ieof2(Channel *c) |
| { |
| debug("channel %d: rcvd eof", c->self); |
| if (c->ostate == CHAN_OUTPUT_OPEN) { |
| debug("channel %d: output open -> drain", c->self); |
| c->ostate = CHAN_OUTPUT_WAIT_DRAIN; |
| } |
| } |
| static void |
| chan_write_failed2(Channel *c) |
| { |
| debug("channel %d: write failed", c->self); |
| switch (c->ostate) { |
| case CHAN_OUTPUT_OPEN: |
| debug("channel %d: output open -> closed", c->self); |
| chan_shutdown_write(c); /* ?? */ |
| c->ostate = CHAN_OUTPUT_CLOSED; |
| break; |
| case CHAN_OUTPUT_WAIT_DRAIN: |
| debug("channel %d: output drain -> closed", c->self); |
| chan_shutdown_write(c); |
| c->ostate = CHAN_OUTPUT_CLOSED; |
| break; |
| default: |
| error("channel %d: chan_write_failed for ostate %d", |
| c->self, c->ostate); |
| break; |
| } |
| } |
| static void |
| chan_obuf_empty2(Channel *c) |
| { |
| debug("channel %d: obuf empty", c->self); |
| if (buffer_len(&c->output)) { |
| error("channel %d: chan_obuf_empty for non empty buffer", |
| c->self); |
| return; |
| } |
| switch (c->ostate) { |
| case CHAN_OUTPUT_WAIT_DRAIN: |
| debug("channel %d: output drain -> closed", c->self); |
| chan_shutdown_write(c); |
| c->ostate = CHAN_OUTPUT_CLOSED; |
| break; |
| default: |
| error("channel %d: chan_obuf_empty for ostate %d", |
| c->self, c->ostate); |
| break; |
| } |
| } |
| static void |
| chan_send_eof2(Channel *c) |
| { |
| debug("channel %d: send eof", c->self); |
| switch (c->istate) { |
| case CHAN_INPUT_WAIT_DRAIN: |
| packet_start(SSH2_MSG_CHANNEL_EOF); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| break; |
| default: |
| error("channel %d: cannot send eof for istate %d", |
| c->self, c->istate); |
| break; |
| } |
| } |
| static void |
| chan_send_close2(Channel *c) |
| { |
| debug("channel %d: send close", c->self); |
| if (c->ostate != CHAN_OUTPUT_CLOSED || |
| c->istate != CHAN_INPUT_CLOSED) { |
| error("channel %d: cannot send close for istate/ostate %d/%d", |
| c->self, c->istate, c->ostate); |
| } else if (c->flags & CHAN_CLOSE_SENT) { |
| error("channel %d: already sent close", c->self); |
| } else { |
| packet_start(SSH2_MSG_CHANNEL_CLOSE); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| c->flags |= CHAN_CLOSE_SENT; |
| } |
| } |
| |
| /* shared */ |
| |
| void |
| chan_mark_dead(Channel *c) |
| { |
| c->type = SSH_CHANNEL_ZOMBIE; |
| } |
| |
| int |
| chan_is_dead(Channel *c, int send) |
| { |
| if (c->type == SSH_CHANNEL_ZOMBIE) { |
| debug("channel %d: zombie", c->self); |
| return 1; |
| } |
| if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED) |
| return 0; |
| if (!compat20) { |
| debug("channel %d: is dead", c->self); |
| return 1; |
| } |
| /* |
| * we have to delay the close message if the efd (for stderr) is |
| * still active |
| */ |
| if (((c->extended_usage != CHAN_EXTENDED_IGNORE) && |
| buffer_len(&c->extended) > 0) |
| #if 0 |
| || ((c->extended_usage == CHAN_EXTENDED_READ) && |
| c->efd != -1) |
| #endif |
| ) { |
| debug2("channel %d: active efd: %d len %d type %s", |
| c->self, c->efd, buffer_len(&c->extended), |
| c->extended_usage==CHAN_EXTENDED_READ ? |
| "read": "write"); |
| } else { |
| if (!(c->flags & CHAN_CLOSE_SENT)) { |
| if (send) { |
| chan_send_close2(c); |
| } else { |
| /* channel would be dead if we sent a close */ |
| if (c->flags & CHAN_CLOSE_RCVD) { |
| debug("channel %d: almost dead", |
| c->self); |
| return 1; |
| } |
| } |
| } |
| if ((c->flags & CHAN_CLOSE_SENT) && |
| (c->flags & CHAN_CLOSE_RCVD)) { |
| debug("channel %d: is dead", c->self); |
| return 1; |
| } |
| } |
| return 0; |
| } |
| |
| void |
| chan_init_iostates(Channel *c) |
| { |
| c->ostate = CHAN_OUTPUT_OPEN; |
| c->istate = CHAN_INPUT_OPEN; |
| c->flags = 0; |
| } |
| |
| /* init */ |
| void |
| chan_init(void) |
| { |
| if (compat20) { |
| chan_rcvd_oclose = chan_rcvd_oclose2; |
| chan_read_failed = chan_read_failed_12; |
| chan_ibuf_empty = chan_ibuf_empty2; |
| |
| chan_rcvd_ieof = chan_rcvd_ieof2; |
| chan_write_failed = chan_write_failed2; |
| chan_obuf_empty = chan_obuf_empty2; |
| } else { |
| chan_rcvd_oclose = chan_rcvd_oclose1; |
| chan_read_failed = chan_read_failed_12; |
| chan_ibuf_empty = chan_ibuf_empty1; |
| |
| chan_rcvd_ieof = chan_rcvd_ieof1; |
| chan_write_failed = chan_write_failed1; |
| chan_obuf_empty = chan_obuf_empty1; |
| } |
| } |
| |
| /* helper */ |
| static void |
| chan_shutdown_write(Channel *c) |
| { |
| buffer_clear(&c->output); |
| if (compat20 && c->type == SSH_CHANNEL_LARVAL) |
| return; |
| /* shutdown failure is allowed if write failed already */ |
| debug("channel %d: close_write", c->self); |
| if (c->sock != -1) { |
| if (shutdown(c->sock, SHUT_WR) < 0) |
| debug("channel %d: chan_shutdown_write: " |
| "shutdown() failed for fd%d: %.100s", |
| c->self, c->sock, strerror(errno)); |
| } else { |
| if (channel_close_fd(&c->wfd) < 0) |
| log("channel %d: chan_shutdown_write: " |
| "close() failed for fd%d: %.100s", |
| c->self, c->wfd, strerror(errno)); |
| } |
| } |
| static void |
| chan_shutdown_read(Channel *c) |
| { |
| if (compat20 && c->type == SSH_CHANNEL_LARVAL) |
| return; |
| debug("channel %d: close_read", c->self); |
| if (c->sock != -1) { |
| /* |
| * shutdown(sock, SHUT_READ) may return ENOTCONN if the |
| * write side has been closed already. (bug on Linux) |
| * HP-UX may return ENOTCONN also. |
| */ |
| if (shutdown(c->sock, SHUT_RD) < 0 |
| && errno != ENOTCONN) |
| error("channel %d: chan_shutdown_read: " |
| "shutdown() failed for fd%d [i%d o%d]: %.100s", |
| c->self, c->sock, c->istate, c->ostate, |
| strerror(errno)); |
| } else { |
| if (channel_close_fd(&c->rfd) < 0) |
| log("channel %d: chan_shutdown_read: " |
| "close() failed for fd%d: %.100s", |
| c->self, c->rfd, strerror(errno)); |
| } |
| } |