Annotation of src/usr.bin/ssh/nchan.c, Revision 1.44
1.7 markus 1: /*
1.43 markus 2: * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
1.7 markus 3: *
4: * Redistribution and use in source and binary forms, with or without
5: * modification, are permitted provided that the following conditions
6: * are met:
7: * 1. Redistributions of source code must retain the above copyright
8: * notice, this list of conditions and the following disclaimer.
9: * 2. Redistributions in binary form must reproduce the above copyright
10: * notice, this list of conditions and the following disclaimer in the
11: * documentation and/or other materials provided with the distribution.
12: *
13: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23: */
24:
1.1 markus 25: #include "includes.h"
1.44 ! markus 26: RCSID("$OpenBSD: nchan.c,v 1.43 2002/01/14 13:57:03 markus Exp $");
1.1 markus 27:
1.22 markus 28: #include "ssh1.h"
29: #include "ssh2.h"
1.1 markus 30: #include "buffer.h"
1.3 markus 31: #include "packet.h"
1.1 markus 32: #include "channels.h"
1.13 markus 33: #include "compat.h"
1.22 markus 34: #include "log.h"
1.3 markus 35:
1.28 markus 36: /*
37: * SSH Protocol 1.5 aka New Channel Protocol
38: * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
39: * Written by Markus Friedl in October 1999
40: *
41: * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
42: * tear down of channels:
43: *
44: * 1.3: strict request-ack-protocol:
45: * CLOSE ->
46: * <- CLOSE_CONFIRM
47: *
48: * 1.5: uses variations of:
49: * IEOF ->
50: * <- OCLOSE
51: * <- IEOF
52: * OCLOSE ->
53: * i.e. both sides have to close the channel
54: *
55: * 2.0: the EOF messages are optional
56: *
57: * See the debugging output from 'ssh -v' and 'sshd -d' of
58: * ssh-1.2.27 as an example.
59: *
60: */
61:
1.13 markus 62: /* functions manipulating channel states */
1.3 markus 63: /*
1.6 markus 64: * EVENTS update channel input/output states execute ACTIONS
1.3 markus 65: */
1.13 markus 66: /*
67: * ACTIONS: should never update the channel states
68: */
1.29 itojun 69: static void chan_send_ieof1(Channel *);
70: static void chan_send_oclose1(Channel *);
71: static void chan_send_close2(Channel *);
72: static void chan_send_eof2(Channel *);
1.13 markus 73:
74: /* helper */
1.29 itojun 75: static void chan_shutdown_write(Channel *);
76: static void chan_shutdown_read(Channel *);
1.13 markus 77:
1.37 markus 78: static char *ostates[] = { "open", "drain", "wait_ieof", "closed" };
79: static char *istates[] = { "open", "drain", "wait_oclose", "closed" };
80:
81: static void
82: chan_set_istate(Channel *c, u_int next)
83: {
84: if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED)
85: fatal("chan_set_istate: bad state %d -> %d", c->istate, next);
86: debug("channel %d: input %s -> %s", c->self, istates[c->istate],
87: istates[next]);
88: c->istate = next;
89: }
90: static void
91: chan_set_ostate(Channel *c, u_int next)
92: {
93: if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED)
94: fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next);
95: debug("channel %d: output %s -> %s", c->self, ostates[c->ostate],
96: ostates[next]);
97: c->ostate = next;
98: }
99:
1.13 markus 100: /*
101: * SSH1 specific implementation of event functions
102: */
1.6 markus 103:
1.13 markus 104: static void
105: chan_rcvd_oclose1(Channel *c)
1.6 markus 106: {
1.13 markus 107: debug("channel %d: rcvd oclose", c->self);
1.6 markus 108: switch (c->istate) {
1.3 markus 109: case CHAN_INPUT_WAIT_OCLOSE:
1.37 markus 110: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.3 markus 111: break;
112: case CHAN_INPUT_OPEN:
113: chan_shutdown_read(c);
1.13 markus 114: chan_send_ieof1(c);
1.37 markus 115: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.10 markus 116: break;
117: case CHAN_INPUT_WAIT_DRAIN:
118: /* both local read_failed and remote write_failed */
1.13 markus 119: chan_send_ieof1(c);
1.37 markus 120: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.3 markus 121: break;
122: default:
1.28 markus 123: error("channel %d: protocol error: rcvd_oclose for istate %d",
1.13 markus 124: c->self, c->istate);
1.10 markus 125: return;
1.3 markus 126: }
1.1 markus 127: }
1.42 markus 128: void
129: chan_read_failed(Channel *c)
1.6 markus 130: {
1.13 markus 131: debug("channel %d: read failed", c->self);
1.6 markus 132: switch (c->istate) {
1.3 markus 133: case CHAN_INPUT_OPEN:
134: chan_shutdown_read(c);
1.37 markus 135: chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
1.3 markus 136: break;
137: default:
1.28 markus 138: error("channel %d: chan_read_failed for istate %d",
1.13 markus 139: c->self, c->istate);
1.3 markus 140: break;
1.1 markus 141: }
142: }
1.42 markus 143: void
144: chan_ibuf_empty(Channel *c)
1.6 markus 145: {
1.13 markus 146: debug("channel %d: ibuf empty", c->self);
1.6 markus 147: if (buffer_len(&c->input)) {
1.28 markus 148: error("channel %d: chan_ibuf_empty for non empty buffer",
1.13 markus 149: c->self);
1.3 markus 150: return;
151: }
1.6 markus 152: switch (c->istate) {
1.3 markus 153: case CHAN_INPUT_WAIT_DRAIN:
1.39 markus 154: if (compat20) {
155: if (!(c->flags & CHAN_CLOSE_SENT))
156: chan_send_eof2(c);
157: chan_set_istate(c, CHAN_INPUT_CLOSED);
158: } else {
159: chan_send_ieof1(c);
160: chan_set_istate(c, CHAN_INPUT_WAIT_OCLOSE);
161: }
1.3 markus 162: break;
163: default:
1.28 markus 164: error("channel %d: chan_ibuf_empty for istate %d",
1.13 markus 165: c->self, c->istate);
1.3 markus 166: break;
1.1 markus 167: }
168: }
1.13 markus 169: static void
170: chan_rcvd_ieof1(Channel *c)
1.6 markus 171: {
1.13 markus 172: debug("channel %d: rcvd ieof", c->self);
1.6 markus 173: switch (c->ostate) {
1.3 markus 174: case CHAN_OUTPUT_OPEN:
1.37 markus 175: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.3 markus 176: break;
177: case CHAN_OUTPUT_WAIT_IEOF:
1.37 markus 178: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 179: break;
180: default:
1.28 markus 181: error("channel %d: protocol error: rcvd_ieof for ostate %d",
1.13 markus 182: c->self, c->ostate);
1.3 markus 183: break;
184: }
185: }
1.13 markus 186: static void
187: chan_write_failed1(Channel *c)
1.6 markus 188: {
1.13 markus 189: debug("channel %d: write failed", c->self);
1.6 markus 190: switch (c->ostate) {
1.3 markus 191: case CHAN_OUTPUT_OPEN:
1.38 markus 192: chan_shutdown_write(c);
1.13 markus 193: chan_send_oclose1(c);
1.37 markus 194: chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF);
1.3 markus 195: break;
196: case CHAN_OUTPUT_WAIT_DRAIN:
1.38 markus 197: chan_shutdown_write(c);
1.13 markus 198: chan_send_oclose1(c);
1.37 markus 199: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 200: break;
201: default:
1.28 markus 202: error("channel %d: chan_write_failed for ostate %d",
1.13 markus 203: c->self, c->ostate);
1.3 markus 204: break;
205: }
206: }
1.42 markus 207: void
208: chan_obuf_empty(Channel *c)
1.6 markus 209: {
1.13 markus 210: debug("channel %d: obuf empty", c->self);
1.6 markus 211: if (buffer_len(&c->output)) {
1.28 markus 212: error("channel %d: chan_obuf_empty for non empty buffer",
1.13 markus 213: c->self);
1.3 markus 214: return;
215: }
1.6 markus 216: switch (c->ostate) {
1.3 markus 217: case CHAN_OUTPUT_WAIT_DRAIN:
1.38 markus 218: chan_shutdown_write(c);
1.39 markus 219: if (!compat20)
220: chan_send_oclose1(c);
1.37 markus 221: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 222: break;
223: default:
1.28 markus 224: error("channel %d: internal error: obuf_empty for ostate %d",
1.13 markus 225: c->self, c->ostate);
1.3 markus 226: break;
227: }
228: }
229: static void
1.13 markus 230: chan_send_ieof1(Channel *c)
1.6 markus 231: {
1.13 markus 232: debug("channel %d: send ieof", c->self);
1.6 markus 233: switch (c->istate) {
1.3 markus 234: case CHAN_INPUT_OPEN:
235: case CHAN_INPUT_WAIT_DRAIN:
236: packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
237: packet_put_int(c->remote_id);
238: packet_send();
239: break;
240: default:
1.28 markus 241: error("channel %d: cannot send ieof for istate %d",
1.13 markus 242: c->self, c->istate);
1.3 markus 243: break;
1.1 markus 244: }
245: }
1.3 markus 246: static void
1.13 markus 247: chan_send_oclose1(Channel *c)
1.6 markus 248: {
1.13 markus 249: debug("channel %d: send oclose", c->self);
1.6 markus 250: switch (c->ostate) {
1.3 markus 251: case CHAN_OUTPUT_OPEN:
252: case CHAN_OUTPUT_WAIT_DRAIN:
1.34 markus 253: buffer_clear(&c->output);
1.3 markus 254: packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
255: packet_put_int(c->remote_id);
256: packet_send();
257: break;
258: default:
1.28 markus 259: error("channel %d: cannot send oclose for ostate %d",
1.33 deraadt 260: c->self, c->ostate);
1.3 markus 261: break;
1.1 markus 262: }
263: }
1.6 markus 264:
1.13 markus 265: /*
266: * the same for SSH2
267: */
268: static void
1.40 markus 269: chan_rcvd_close2(Channel *c)
1.13 markus 270: {
271: debug("channel %d: rcvd close", c->self);
272: if (c->flags & CHAN_CLOSE_RCVD)
273: error("channel %d: protocol error: close rcvd twice", c->self);
274: c->flags |= CHAN_CLOSE_RCVD;
275: if (c->type == SSH_CHANNEL_LARVAL) {
276: /* tear down larval channels immediately */
1.37 markus 277: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
278: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 279: return;
280: }
281: switch (c->ostate) {
282: case CHAN_OUTPUT_OPEN:
1.28 markus 283: /*
284: * wait until a data from the channel is consumed if a CLOSE
285: * is received
286: */
1.37 markus 287: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.13 markus 288: break;
289: }
290: switch (c->istate) {
291: case CHAN_INPUT_OPEN:
292: chan_shutdown_read(c);
1.40 markus 293: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 294: break;
295: case CHAN_INPUT_WAIT_DRAIN:
296: chan_send_eof2(c);
1.40 markus 297: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 298: break;
299: }
300: }
301: static void
1.40 markus 302: chan_rcvd_eof2(Channel *c)
1.13 markus 303: {
304: debug("channel %d: rcvd eof", c->self);
1.37 markus 305: if (c->ostate == CHAN_OUTPUT_OPEN)
306: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.13 markus 307: }
308: static void
309: chan_write_failed2(Channel *c)
310: {
311: debug("channel %d: write failed", c->self);
312: switch (c->ostate) {
313: case CHAN_OUTPUT_OPEN:
314: case CHAN_OUTPUT_WAIT_DRAIN:
315: chan_shutdown_write(c);
1.37 markus 316: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.13 markus 317: break;
318: default:
1.28 markus 319: error("channel %d: chan_write_failed for ostate %d",
1.13 markus 320: c->self, c->ostate);
321: break;
322: }
323: }
324: static void
325: chan_send_eof2(Channel *c)
1.6 markus 326: {
1.13 markus 327: debug("channel %d: send eof", c->self);
328: switch (c->istate) {
329: case CHAN_INPUT_WAIT_DRAIN:
330: packet_start(SSH2_MSG_CHANNEL_EOF);
331: packet_put_int(c->remote_id);
332: packet_send();
333: break;
334: default:
1.28 markus 335: error("channel %d: cannot send eof for istate %d",
1.13 markus 336: c->self, c->istate);
337: break;
338: }
1.1 markus 339: }
1.3 markus 340: static void
1.13 markus 341: chan_send_close2(Channel *c)
1.6 markus 342: {
1.13 markus 343: debug("channel %d: send close", c->self);
344: if (c->ostate != CHAN_OUTPUT_CLOSED ||
345: c->istate != CHAN_INPUT_CLOSED) {
1.28 markus 346: error("channel %d: cannot send close for istate/ostate %d/%d",
1.13 markus 347: c->self, c->istate, c->ostate);
348: } else if (c->flags & CHAN_CLOSE_SENT) {
1.28 markus 349: error("channel %d: already sent close", c->self);
1.13 markus 350: } else {
351: packet_start(SSH2_MSG_CHANNEL_CLOSE);
352: packet_put_int(c->remote_id);
353: packet_send();
354: c->flags |= CHAN_CLOSE_SENT;
355: }
1.1 markus 356: }
1.23 markus 357:
358: /* shared */
359:
1.24 markus 360: void
1.42 markus 361: chan_rcvd_ieof(Channel *c)
362: {
363: if (compat20)
364: chan_rcvd_eof2(c);
365: else
366: chan_rcvd_ieof1(c);
1.44 ! markus 367: if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN &&
! 368: buffer_len(&c->output) == 0)
! 369: chan_obuf_empty(c);
1.42 markus 370: }
371: void
372: chan_rcvd_oclose(Channel *c)
373: {
374: if (compat20)
375: chan_rcvd_close2(c);
376: else
377: chan_rcvd_oclose1(c);
378: }
379: void
380: chan_write_failed(Channel *c)
381: {
382: if (compat20)
383: chan_write_failed2(c);
384: else
385: chan_write_failed1(c);
386: }
387:
388: void
1.24 markus 389: chan_mark_dead(Channel *c)
390: {
1.26 markus 391: c->type = SSH_CHANNEL_ZOMBIE;
1.24 markus 392: }
393:
1.23 markus 394: int
1.32 markus 395: chan_is_dead(Channel *c, int send)
1.6 markus 396: {
1.26 markus 397: if (c->type == SSH_CHANNEL_ZOMBIE) {
398: debug("channel %d: zombie", c->self);
1.24 markus 399: return 1;
1.26 markus 400: }
1.23 markus 401: if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
402: return 0;
403: if (!compat20) {
404: debug("channel %d: is dead", c->self);
405: return 1;
406: }
407: /*
408: * we have to delay the close message if the efd (for stderr) is
409: * still active
410: */
411: if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
412: buffer_len(&c->extended) > 0)
413: #if 0
414: || ((c->extended_usage == CHAN_EXTENDED_READ) &&
415: c->efd != -1)
416: #endif
417: ) {
418: debug2("channel %d: active efd: %d len %d type %s",
419: c->self, c->efd, buffer_len(&c->extended),
420: c->extended_usage==CHAN_EXTENDED_READ ?
1.33 deraadt 421: "read": "write");
1.23 markus 422: } else {
1.13 markus 423: if (!(c->flags & CHAN_CLOSE_SENT)) {
1.32 markus 424: if (send) {
425: chan_send_close2(c);
426: } else {
427: /* channel would be dead if we sent a close */
428: if (c->flags & CHAN_CLOSE_RCVD) {
429: debug("channel %d: almost dead",
430: c->self);
431: return 1;
432: }
433: }
1.13 markus 434: }
1.14 markus 435: if ((c->flags & CHAN_CLOSE_SENT) &&
1.13 markus 436: (c->flags & CHAN_CLOSE_RCVD)) {
1.23 markus 437: debug("channel %d: is dead", c->self);
438: return 1;
1.14 markus 439: }
1.1 markus 440: }
1.23 markus 441: return 0;
1.13 markus 442: }
443:
444: /* helper */
445: static void
446: chan_shutdown_write(Channel *c)
447: {
1.34 markus 448: buffer_clear(&c->output);
1.13 markus 449: if (compat20 && c->type == SSH_CHANNEL_LARVAL)
450: return;
451: /* shutdown failure is allowed if write failed already */
452: debug("channel %d: close_write", c->self);
453: if (c->sock != -1) {
454: if (shutdown(c->sock, SHUT_WR) < 0)
1.28 markus 455: debug("channel %d: chan_shutdown_write: "
456: "shutdown() failed for fd%d: %.100s",
1.13 markus 457: c->self, c->sock, strerror(errno));
458: } else {
1.31 markus 459: if (channel_close_fd(&c->wfd) < 0)
1.28 markus 460: log("channel %d: chan_shutdown_write: "
461: "close() failed for fd%d: %.100s",
1.13 markus 462: c->self, c->wfd, strerror(errno));
463: }
464: }
465: static void
466: chan_shutdown_read(Channel *c)
467: {
468: if (compat20 && c->type == SSH_CHANNEL_LARVAL)
469: return;
470: debug("channel %d: close_read", c->self);
471: if (c->sock != -1) {
472: if (shutdown(c->sock, SHUT_RD) < 0)
1.28 markus 473: error("channel %d: chan_shutdown_read: "
474: "shutdown() failed for fd%d [i%d o%d]: %.100s",
475: c->self, c->sock, c->istate, c->ostate,
476: strerror(errno));
1.13 markus 477: } else {
1.31 markus 478: if (channel_close_fd(&c->rfd) < 0)
1.28 markus 479: log("channel %d: chan_shutdown_read: "
480: "close() failed for fd%d: %.100s",
1.13 markus 481: c->self, c->rfd, strerror(errno));
482: }
1.1 markus 483: }
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