Annotation of src/usr.bin/ssh/nchan.c, Revision 1.64
1.64 ! djm 1: /* $OpenBSD: nchan.c,v 1.63 2010/01/26 01:28:35 djm Exp $ */
1.7 markus 2: /*
1.43 markus 3: * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
1.7 markus 4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: *
14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24: */
25:
1.54 stevesk 26: #include <sys/types.h>
27: #include <sys/socket.h>
1.58 djm 28: #include <sys/queue.h>
1.55 stevesk 29:
30: #include <errno.h>
1.56 stevesk 31: #include <string.h>
1.57 deraadt 32: #include <stdarg.h>
1.1 markus 33:
1.22 markus 34: #include "ssh1.h"
35: #include "ssh2.h"
1.1 markus 36: #include "buffer.h"
1.3 markus 37: #include "packet.h"
1.1 markus 38: #include "channels.h"
1.13 markus 39: #include "compat.h"
1.22 markus 40: #include "log.h"
1.3 markus 41:
1.28 markus 42: /*
43: * SSH Protocol 1.5 aka New Channel Protocol
44: * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
45: * Written by Markus Friedl in October 1999
46: *
47: * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
48: * tear down of channels:
49: *
50: * 1.3: strict request-ack-protocol:
1.51 deraadt 51: * CLOSE ->
52: * <- CLOSE_CONFIRM
1.28 markus 53: *
54: * 1.5: uses variations of:
1.51 deraadt 55: * IEOF ->
56: * <- OCLOSE
57: * <- IEOF
58: * OCLOSE ->
59: * i.e. both sides have to close the channel
1.28 markus 60: *
61: * 2.0: the EOF messages are optional
62: *
63: * See the debugging output from 'ssh -v' and 'sshd -d' of
64: * ssh-1.2.27 as an example.
65: *
66: */
67:
1.13 markus 68: /* functions manipulating channel states */
1.3 markus 69: /*
1.6 markus 70: * EVENTS update channel input/output states execute ACTIONS
1.3 markus 71: */
1.13 markus 72: /*
73: * ACTIONS: should never update the channel states
74: */
1.29 itojun 75: static void chan_send_eof2(Channel *);
1.59 markus 76: static void chan_send_eow2(Channel *);
1.13 markus 77:
78: /* helper */
1.29 itojun 79: static void chan_shutdown_write(Channel *);
80: static void chan_shutdown_read(Channel *);
1.13 markus 81:
1.37 markus 82: static char *ostates[] = { "open", "drain", "wait_ieof", "closed" };
83: static char *istates[] = { "open", "drain", "wait_oclose", "closed" };
84:
85: static void
86: chan_set_istate(Channel *c, u_int next)
87: {
88: if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED)
89: fatal("chan_set_istate: bad state %d -> %d", c->istate, next);
1.49 markus 90: debug2("channel %d: input %s -> %s", c->self, istates[c->istate],
1.37 markus 91: istates[next]);
92: c->istate = next;
93: }
1.64 ! djm 94:
1.37 markus 95: static void
96: chan_set_ostate(Channel *c, u_int next)
97: {
98: if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED)
99: fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next);
1.49 markus 100: debug2("channel %d: output %s -> %s", c->self, ostates[c->ostate],
1.37 markus 101: ostates[next]);
102: c->ostate = next;
103: }
104:
1.42 markus 105: void
106: chan_read_failed(Channel *c)
1.6 markus 107: {
1.49 markus 108: debug2("channel %d: read failed", c->self);
1.6 markus 109: switch (c->istate) {
1.3 markus 110: case CHAN_INPUT_OPEN:
111: chan_shutdown_read(c);
1.37 markus 112: chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
1.3 markus 113: break;
114: default:
1.28 markus 115: error("channel %d: chan_read_failed for istate %d",
1.13 markus 116: c->self, c->istate);
1.3 markus 117: break;
1.1 markus 118: }
119: }
1.64 ! djm 120:
1.42 markus 121: void
122: chan_ibuf_empty(Channel *c)
1.6 markus 123: {
1.49 markus 124: debug2("channel %d: ibuf empty", c->self);
1.6 markus 125: if (buffer_len(&c->input)) {
1.28 markus 126: error("channel %d: chan_ibuf_empty for non empty buffer",
1.13 markus 127: c->self);
1.3 markus 128: return;
129: }
1.6 markus 130: switch (c->istate) {
1.3 markus 131: case CHAN_INPUT_WAIT_DRAIN:
1.64 ! djm 132: if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_LOCAL)))
! 133: chan_send_eof2(c);
! 134: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.3 markus 135: break;
136: default:
1.28 markus 137: error("channel %d: chan_ibuf_empty for istate %d",
1.13 markus 138: c->self, c->istate);
1.3 markus 139: break;
1.1 markus 140: }
141: }
1.64 ! djm 142:
1.42 markus 143: void
144: chan_obuf_empty(Channel *c)
1.6 markus 145: {
1.49 markus 146: debug2("channel %d: obuf empty", c->self);
1.6 markus 147: if (buffer_len(&c->output)) {
1.28 markus 148: error("channel %d: chan_obuf_empty for non empty buffer",
1.13 markus 149: c->self);
1.3 markus 150: return;
151: }
1.6 markus 152: switch (c->ostate) {
1.3 markus 153: case CHAN_OUTPUT_WAIT_DRAIN:
1.38 markus 154: chan_shutdown_write(c);
1.37 markus 155: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 156: break;
157: default:
1.28 markus 158: error("channel %d: internal error: obuf_empty for ostate %d",
1.13 markus 159: c->self, c->ostate);
1.3 markus 160: break;
161: }
162: }
1.63 djm 163:
1.59 markus 164: void
165: chan_rcvd_eow(Channel *c)
166: {
167: debug2("channel %d: rcvd eow", c->self);
168: switch (c->istate) {
169: case CHAN_INPUT_OPEN:
170: chan_shutdown_read(c);
171: chan_set_istate(c, CHAN_INPUT_CLOSED);
172: break;
173: }
174: }
1.64 ! djm 175:
1.13 markus 176: static void
177: chan_send_eof2(Channel *c)
1.6 markus 178: {
1.49 markus 179: debug2("channel %d: send eof", c->self);
1.13 markus 180: switch (c->istate) {
181: case CHAN_INPUT_WAIT_DRAIN:
182: packet_start(SSH2_MSG_CHANNEL_EOF);
183: packet_put_int(c->remote_id);
184: packet_send();
1.45 markus 185: c->flags |= CHAN_EOF_SENT;
1.13 markus 186: break;
187: default:
1.28 markus 188: error("channel %d: cannot send eof for istate %d",
1.13 markus 189: c->self, c->istate);
190: break;
191: }
1.1 markus 192: }
1.64 ! djm 193:
1.3 markus 194: static void
1.13 markus 195: chan_send_close2(Channel *c)
1.6 markus 196: {
1.49 markus 197: debug2("channel %d: send close", c->self);
1.13 markus 198: if (c->ostate != CHAN_OUTPUT_CLOSED ||
199: c->istate != CHAN_INPUT_CLOSED) {
1.28 markus 200: error("channel %d: cannot send close for istate/ostate %d/%d",
1.13 markus 201: c->self, c->istate, c->ostate);
202: } else if (c->flags & CHAN_CLOSE_SENT) {
1.28 markus 203: error("channel %d: already sent close", c->self);
1.13 markus 204: } else {
205: packet_start(SSH2_MSG_CHANNEL_CLOSE);
206: packet_put_int(c->remote_id);
207: packet_send();
208: c->flags |= CHAN_CLOSE_SENT;
209: }
1.59 markus 210: }
1.64 ! djm 211:
1.59 markus 212: static void
213: chan_send_eow2(Channel *c)
214: {
215: debug2("channel %d: send eow", c->self);
216: if (c->ostate == CHAN_OUTPUT_CLOSED) {
217: error("channel %d: must not sent eow on closed output",
218: c->self);
219: return;
220: }
1.61 markus 221: if (!(datafellows & SSH_NEW_OPENSSH))
222: return;
1.59 markus 223: packet_start(SSH2_MSG_CHANNEL_REQUEST);
224: packet_put_int(c->remote_id);
225: packet_put_cstring("eow@openssh.com");
226: packet_put_char(0);
227: packet_send();
1.1 markus 228: }
1.23 markus 229:
230: /* shared */
231:
1.24 markus 232: void
1.42 markus 233: chan_rcvd_ieof(Channel *c)
234: {
1.64 ! djm 235: debug2("channel %d: rcvd eof", c->self);
! 236: c->flags |= CHAN_EOF_RCVD;
! 237: if (c->ostate == CHAN_OUTPUT_OPEN)
! 238: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.44 markus 239: if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN &&
1.47 deraadt 240: buffer_len(&c->output) == 0 &&
1.45 markus 241: !CHANNEL_EFD_OUTPUT_ACTIVE(c))
1.44 markus 242: chan_obuf_empty(c);
1.42 markus 243: }
1.64 ! djm 244:
1.42 markus 245: void
246: chan_rcvd_oclose(Channel *c)
247: {
1.64 ! djm 248: debug2("channel %d: rcvd close", c->self);
! 249: if (!(c->flags & CHAN_LOCAL)) {
! 250: if (c->flags & CHAN_CLOSE_RCVD)
! 251: error("channel %d: protocol error: close rcvd twice",
! 252: c->self);
! 253: c->flags |= CHAN_CLOSE_RCVD;
! 254: }
! 255: if (c->type == SSH_CHANNEL_LARVAL) {
! 256: /* tear down larval channels immediately */
! 257: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
! 258: chan_set_istate(c, CHAN_INPUT_CLOSED);
! 259: return;
! 260: }
! 261: switch (c->ostate) {
! 262: case CHAN_OUTPUT_OPEN:
! 263: /*
! 264: * wait until a data from the channel is consumed if a CLOSE
! 265: * is received
! 266: */
! 267: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
! 268: break;
! 269: }
! 270: switch (c->istate) {
! 271: case CHAN_INPUT_OPEN:
! 272: chan_shutdown_read(c);
! 273: chan_set_istate(c, CHAN_INPUT_CLOSED);
! 274: break;
! 275: case CHAN_INPUT_WAIT_DRAIN:
! 276: if (!(c->flags & CHAN_LOCAL))
! 277: chan_send_eof2(c);
! 278: chan_set_istate(c, CHAN_INPUT_CLOSED);
! 279: break;
! 280: }
1.42 markus 281: }
1.64 ! djm 282:
1.42 markus 283: void
284: chan_write_failed(Channel *c)
285: {
1.64 ! djm 286: debug2("channel %d: write failed", c->self);
! 287: switch (c->ostate) {
! 288: case CHAN_OUTPUT_OPEN:
! 289: case CHAN_OUTPUT_WAIT_DRAIN:
! 290: chan_shutdown_write(c);
! 291: if (strcmp(c->ctype, "session") == 0)
! 292: chan_send_eow2(c);
! 293: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
! 294: break;
! 295: default:
! 296: error("channel %d: chan_write_failed for ostate %d",
! 297: c->self, c->ostate);
! 298: break;
! 299: }
1.42 markus 300: }
301:
302: void
1.24 markus 303: chan_mark_dead(Channel *c)
304: {
1.26 markus 305: c->type = SSH_CHANNEL_ZOMBIE;
1.24 markus 306: }
307:
1.23 markus 308: int
1.50 avsm 309: chan_is_dead(Channel *c, int do_send)
1.6 markus 310: {
1.26 markus 311: if (c->type == SSH_CHANNEL_ZOMBIE) {
1.49 markus 312: debug2("channel %d: zombie", c->self);
1.24 markus 313: return 1;
1.26 markus 314: }
1.23 markus 315: if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
316: return 0;
1.45 markus 317: if ((datafellows & SSH_BUG_EXTEOF) &&
318: c->extended_usage == CHAN_EXTENDED_WRITE &&
319: c->efd != -1 &&
320: buffer_len(&c->extended) > 0) {
1.46 markus 321: debug2("channel %d: active efd: %d len %d",
322: c->self, c->efd, buffer_len(&c->extended));
1.45 markus 323: return 0;
324: }
1.63 djm 325: if (c->flags & CHAN_LOCAL) {
326: debug2("channel %d: is dead (local)", c->self);
327: return 1;
328: }
1.45 markus 329: if (!(c->flags & CHAN_CLOSE_SENT)) {
1.50 avsm 330: if (do_send) {
1.45 markus 331: chan_send_close2(c);
332: } else {
333: /* channel would be dead if we sent a close */
334: if (c->flags & CHAN_CLOSE_RCVD) {
1.49 markus 335: debug2("channel %d: almost dead",
1.45 markus 336: c->self);
337: return 1;
1.32 markus 338: }
1.13 markus 339: }
1.45 markus 340: }
341: if ((c->flags & CHAN_CLOSE_SENT) &&
342: (c->flags & CHAN_CLOSE_RCVD)) {
1.49 markus 343: debug2("channel %d: is dead", c->self);
1.45 markus 344: return 1;
1.1 markus 345: }
1.23 markus 346: return 0;
1.13 markus 347: }
348:
349: /* helper */
350: static void
351: chan_shutdown_write(Channel *c)
352: {
1.34 markus 353: buffer_clear(&c->output);
1.64 ! djm 354: if (c->type == SSH_CHANNEL_LARVAL)
1.13 markus 355: return;
356: /* shutdown failure is allowed if write failed already */
1.49 markus 357: debug2("channel %d: close_write", c->self);
1.13 markus 358: if (c->sock != -1) {
359: if (shutdown(c->sock, SHUT_WR) < 0)
1.49 markus 360: debug2("channel %d: chan_shutdown_write: "
1.62 stevesk 361: "shutdown() failed for fd %d: %.100s",
1.13 markus 362: c->self, c->sock, strerror(errno));
363: } else {
1.31 markus 364: if (channel_close_fd(&c->wfd) < 0)
1.48 itojun 365: logit("channel %d: chan_shutdown_write: "
1.62 stevesk 366: "close() failed for fd %d: %.100s",
1.13 markus 367: c->self, c->wfd, strerror(errno));
368: }
369: }
1.64 ! djm 370:
1.13 markus 371: static void
372: chan_shutdown_read(Channel *c)
373: {
1.64 ! djm 374: if (c->type == SSH_CHANNEL_LARVAL)
1.13 markus 375: return;
1.49 markus 376: debug2("channel %d: close_read", c->self);
1.13 markus 377: if (c->sock != -1) {
378: if (shutdown(c->sock, SHUT_RD) < 0)
1.28 markus 379: error("channel %d: chan_shutdown_read: "
1.62 stevesk 380: "shutdown() failed for fd %d [i%d o%d]: %.100s",
1.28 markus 381: c->self, c->sock, c->istate, c->ostate,
382: strerror(errno));
1.13 markus 383: } else {
1.31 markus 384: if (channel_close_fd(&c->rfd) < 0)
1.48 itojun 385: logit("channel %d: chan_shutdown_read: "
1.62 stevesk 386: "close() failed for fd %d: %.100s",
1.13 markus 387: c->self, c->rfd, strerror(errno));
388: }
1.1 markus 389: }
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