Annotation of src/usr.bin/ssh/nchan.c, Revision 1.30
1.7 markus 1: /*
1.30 ! markus 2: * Copyright (c) 1999, 2000, 2001 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"
1.30 ! markus 26: RCSID("$OpenBSD: nchan.c,v 1.29 2001/06/23 15:12:19 itojun 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: /* events concerning the INPUT from socket for channel (istate) */
67: chan_event_fn *chan_rcvd_oclose = NULL;
68: chan_event_fn *chan_read_failed = NULL;
69: chan_event_fn *chan_ibuf_empty = NULL;
70: /* events concerning the OUTPUT from channel for socket (ostate) */
71: chan_event_fn *chan_rcvd_ieof = NULL;
72: chan_event_fn *chan_write_failed = NULL;
73: chan_event_fn *chan_obuf_empty = NULL;
74: /*
75: * ACTIONS: should never update the channel states
76: */
1.29 itojun 77: static void chan_send_ieof1(Channel *);
78: static void chan_send_oclose1(Channel *);
79: static void chan_send_close2(Channel *);
80: static void chan_send_eof2(Channel *);
1.13 markus 81:
82: /* helper */
1.29 itojun 83: static void chan_shutdown_write(Channel *);
84: static void chan_shutdown_read(Channel *);
1.13 markus 85:
86: /*
87: * SSH1 specific implementation of event functions
88: */
1.6 markus 89:
1.13 markus 90: static void
91: chan_rcvd_oclose1(Channel *c)
1.6 markus 92: {
1.13 markus 93: debug("channel %d: rcvd oclose", c->self);
1.6 markus 94: switch (c->istate) {
1.3 markus 95: case CHAN_INPUT_WAIT_OCLOSE:
1.13 markus 96: debug("channel %d: input wait_oclose -> closed", c->self);
1.6 markus 97: c->istate = CHAN_INPUT_CLOSED;
1.3 markus 98: break;
99: case CHAN_INPUT_OPEN:
1.13 markus 100: debug("channel %d: input open -> closed", c->self);
1.3 markus 101: chan_shutdown_read(c);
1.13 markus 102: chan_send_ieof1(c);
1.6 markus 103: c->istate = CHAN_INPUT_CLOSED;
1.10 markus 104: break;
105: case CHAN_INPUT_WAIT_DRAIN:
106: /* both local read_failed and remote write_failed */
1.13 markus 107: log("channel %d: input drain -> closed", c->self);
108: chan_send_ieof1(c);
1.10 markus 109: c->istate = CHAN_INPUT_CLOSED;
1.3 markus 110: break;
111: default:
1.28 markus 112: error("channel %d: protocol error: rcvd_oclose for istate %d",
1.13 markus 113: c->self, c->istate);
1.10 markus 114: return;
1.3 markus 115: }
1.1 markus 116: }
1.13 markus 117: static void
118: chan_read_failed_12(Channel *c)
1.6 markus 119: {
1.13 markus 120: debug("channel %d: read failed", c->self);
1.6 markus 121: switch (c->istate) {
1.3 markus 122: case CHAN_INPUT_OPEN:
1.13 markus 123: debug("channel %d: input open -> drain", c->self);
1.3 markus 124: chan_shutdown_read(c);
1.6 markus 125: c->istate = CHAN_INPUT_WAIT_DRAIN;
1.28 markus 126: #if 0
1.17 markus 127: if (buffer_len(&c->input) == 0) {
128: debug("channel %d: input: no drain shortcut", c->self);
129: chan_ibuf_empty(c);
130: }
1.28 markus 131: #endif
1.3 markus 132: break;
133: default:
1.28 markus 134: error("channel %d: chan_read_failed for istate %d",
1.13 markus 135: c->self, c->istate);
1.3 markus 136: break;
1.1 markus 137: }
138: }
1.13 markus 139: static void
140: chan_ibuf_empty1(Channel *c)
1.6 markus 141: {
1.13 markus 142: debug("channel %d: ibuf empty", c->self);
1.6 markus 143: if (buffer_len(&c->input)) {
1.28 markus 144: error("channel %d: chan_ibuf_empty for non empty buffer",
1.13 markus 145: c->self);
1.3 markus 146: return;
147: }
1.6 markus 148: switch (c->istate) {
1.3 markus 149: case CHAN_INPUT_WAIT_DRAIN:
1.13 markus 150: debug("channel %d: input drain -> wait_oclose", c->self);
151: chan_send_ieof1(c);
1.6 markus 152: c->istate = CHAN_INPUT_WAIT_OCLOSE;
1.3 markus 153: break;
154: default:
1.28 markus 155: error("channel %d: chan_ibuf_empty for istate %d",
1.13 markus 156: c->self, c->istate);
1.3 markus 157: break;
1.1 markus 158: }
159: }
1.13 markus 160: static void
161: chan_rcvd_ieof1(Channel *c)
1.6 markus 162: {
1.13 markus 163: debug("channel %d: rcvd ieof", c->self);
1.16 markus 164: if (c->type != SSH_CHANNEL_OPEN) {
165: debug("channel %d: non-open", c->self);
166: if (c->istate == CHAN_INPUT_OPEN) {
1.28 markus 167: debug("channel %d: non-open: input open -> wait_oclose",
168: c->self);
1.16 markus 169: chan_shutdown_read(c);
170: chan_send_ieof1(c);
171: c->istate = CHAN_INPUT_WAIT_OCLOSE;
172: } else {
1.28 markus 173: error("channel %d: non-open: istate %d != open",
174: c->self, c->istate);
1.16 markus 175: }
176: if (c->ostate == CHAN_OUTPUT_OPEN) {
1.28 markus 177: debug("channel %d: non-open: output open -> closed",
178: c->self);
1.16 markus 179: chan_send_oclose1(c);
180: c->ostate = CHAN_OUTPUT_CLOSED;
181: } else {
1.28 markus 182: error("channel %d: non-open: ostate %d != open",
183: c->self, c->ostate);
1.16 markus 184: }
185: return;
186: }
1.6 markus 187: switch (c->ostate) {
1.3 markus 188: case CHAN_OUTPUT_OPEN:
1.13 markus 189: debug("channel %d: output open -> drain", c->self);
1.6 markus 190: c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
1.3 markus 191: break;
192: case CHAN_OUTPUT_WAIT_IEOF:
1.13 markus 193: debug("channel %d: output wait_ieof -> closed", c->self);
1.6 markus 194: c->ostate = CHAN_OUTPUT_CLOSED;
1.3 markus 195: break;
196: default:
1.28 markus 197: error("channel %d: protocol error: rcvd_ieof for ostate %d",
1.13 markus 198: c->self, c->ostate);
1.3 markus 199: break;
200: }
201: }
1.13 markus 202: static void
203: chan_write_failed1(Channel *c)
1.6 markus 204: {
1.13 markus 205: debug("channel %d: write failed", c->self);
1.6 markus 206: switch (c->ostate) {
1.3 markus 207: case CHAN_OUTPUT_OPEN:
1.13 markus 208: debug("channel %d: output open -> wait_ieof", c->self);
209: chan_send_oclose1(c);
1.6 markus 210: c->ostate = CHAN_OUTPUT_WAIT_IEOF;
1.3 markus 211: break;
212: case CHAN_OUTPUT_WAIT_DRAIN:
1.13 markus 213: debug("channel %d: output wait_drain -> closed", c->self);
214: chan_send_oclose1(c);
1.6 markus 215: c->ostate = CHAN_OUTPUT_CLOSED;
1.3 markus 216: break;
217: default:
1.28 markus 218: error("channel %d: chan_write_failed for ostate %d",
1.13 markus 219: c->self, c->ostate);
1.3 markus 220: break;
221: }
222: }
1.13 markus 223: static void
224: chan_obuf_empty1(Channel *c)
1.6 markus 225: {
1.13 markus 226: debug("channel %d: obuf empty", c->self);
1.6 markus 227: if (buffer_len(&c->output)) {
1.28 markus 228: error("channel %d: chan_obuf_empty for non empty buffer",
1.13 markus 229: c->self);
1.3 markus 230: return;
231: }
1.6 markus 232: switch (c->ostate) {
1.3 markus 233: case CHAN_OUTPUT_WAIT_DRAIN:
1.13 markus 234: debug("channel %d: output drain -> closed", c->self);
235: chan_send_oclose1(c);
1.6 markus 236: c->ostate = CHAN_OUTPUT_CLOSED;
1.3 markus 237: break;
238: default:
1.28 markus 239: error("channel %d: internal error: obuf_empty for ostate %d",
1.13 markus 240: c->self, c->ostate);
1.3 markus 241: break;
242: }
243: }
244: static void
1.13 markus 245: chan_send_ieof1(Channel *c)
1.6 markus 246: {
1.13 markus 247: debug("channel %d: send ieof", c->self);
1.6 markus 248: switch (c->istate) {
1.3 markus 249: case CHAN_INPUT_OPEN:
250: case CHAN_INPUT_WAIT_DRAIN:
251: packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
252: packet_put_int(c->remote_id);
253: packet_send();
254: break;
255: default:
1.28 markus 256: error("channel %d: cannot send ieof for istate %d",
1.13 markus 257: c->self, c->istate);
1.3 markus 258: break;
1.1 markus 259: }
260: }
1.3 markus 261: static void
1.13 markus 262: chan_send_oclose1(Channel *c)
1.6 markus 263: {
1.13 markus 264: debug("channel %d: send oclose", c->self);
1.6 markus 265: switch (c->ostate) {
1.3 markus 266: case CHAN_OUTPUT_OPEN:
267: case CHAN_OUTPUT_WAIT_DRAIN:
268: chan_shutdown_write(c);
269: buffer_consume(&c->output, buffer_len(&c->output));
270: packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
271: packet_put_int(c->remote_id);
272: packet_send();
273: break;
274: default:
1.28 markus 275: error("channel %d: cannot send oclose for ostate %d",
1.13 markus 276: c->self, c->ostate);
1.3 markus 277: break;
1.1 markus 278: }
279: }
1.6 markus 280:
1.13 markus 281: /*
282: * the same for SSH2
283: */
284: static void
285: chan_rcvd_oclose2(Channel *c)
286: {
287: debug("channel %d: rcvd close", c->self);
288: if (c->flags & CHAN_CLOSE_RCVD)
289: error("channel %d: protocol error: close rcvd twice", c->self);
290: c->flags |= CHAN_CLOSE_RCVD;
291: if (c->type == SSH_CHANNEL_LARVAL) {
292: /* tear down larval channels immediately */
293: c->ostate = CHAN_OUTPUT_CLOSED;
294: c->istate = CHAN_INPUT_CLOSED;
295: return;
296: }
297: switch (c->ostate) {
298: case CHAN_OUTPUT_OPEN:
1.28 markus 299: /*
300: * wait until a data from the channel is consumed if a CLOSE
301: * is received
302: */
1.13 markus 303: debug("channel %d: output open -> drain", c->self);
304: c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
305: break;
306: }
307: switch (c->istate) {
308: case CHAN_INPUT_OPEN:
309: debug("channel %d: input open -> closed", c->self);
310: chan_shutdown_read(c);
311: break;
312: case CHAN_INPUT_WAIT_DRAIN:
313: debug("channel %d: input drain -> closed", c->self);
314: chan_send_eof2(c);
315: break;
316: }
317: c->istate = CHAN_INPUT_CLOSED;
318: }
319: static void
320: chan_ibuf_empty2(Channel *c)
321: {
322: debug("channel %d: ibuf empty", c->self);
323: if (buffer_len(&c->input)) {
1.28 markus 324: error("channel %d: chan_ibuf_empty for non empty buffer",
1.13 markus 325: c->self);
326: return;
327: }
328: switch (c->istate) {
329: case CHAN_INPUT_WAIT_DRAIN:
330: debug("channel %d: input drain -> closed", c->self);
331: if (!(c->flags & CHAN_CLOSE_SENT))
332: chan_send_eof2(c);
333: c->istate = CHAN_INPUT_CLOSED;
334: break;
335: default:
1.28 markus 336: error("channel %d: chan_ibuf_empty for istate %d",
1.13 markus 337: c->self, c->istate);
338: break;
339: }
340: }
341: static void
342: chan_rcvd_ieof2(Channel *c)
343: {
344: debug("channel %d: rcvd eof", c->self);
345: if (c->ostate == CHAN_OUTPUT_OPEN) {
346: debug("channel %d: output open -> drain", c->self);
347: c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
348: }
349: }
350: static void
351: chan_write_failed2(Channel *c)
352: {
353: debug("channel %d: write failed", c->self);
354: switch (c->ostate) {
355: case CHAN_OUTPUT_OPEN:
356: debug("channel %d: output open -> closed", c->self);
1.15 markus 357: chan_shutdown_write(c); /* ?? */
1.13 markus 358: c->ostate = CHAN_OUTPUT_CLOSED;
359: break;
360: case CHAN_OUTPUT_WAIT_DRAIN:
361: debug("channel %d: output drain -> closed", c->self);
362: chan_shutdown_write(c);
363: c->ostate = CHAN_OUTPUT_CLOSED;
364: break;
365: default:
1.28 markus 366: error("channel %d: chan_write_failed for ostate %d",
1.13 markus 367: c->self, c->ostate);
368: break;
369: }
370: }
371: static void
372: chan_obuf_empty2(Channel *c)
373: {
374: debug("channel %d: obuf empty", c->self);
375: if (buffer_len(&c->output)) {
1.28 markus 376: error("channel %d: chan_obuf_empty for non empty buffer",
1.13 markus 377: c->self);
378: return;
379: }
380: switch (c->ostate) {
381: case CHAN_OUTPUT_WAIT_DRAIN:
382: debug("channel %d: output drain -> closed", c->self);
383: chan_shutdown_write(c);
384: c->ostate = CHAN_OUTPUT_CLOSED;
385: break;
386: default:
1.28 markus 387: error("channel %d: chan_obuf_empty for ostate %d",
1.13 markus 388: c->self, c->ostate);
389: break;
390: }
391: }
1.3 markus 392: static void
1.13 markus 393: chan_send_eof2(Channel *c)
1.6 markus 394: {
1.13 markus 395: debug("channel %d: send eof", c->self);
396: switch (c->istate) {
397: case CHAN_INPUT_WAIT_DRAIN:
398: packet_start(SSH2_MSG_CHANNEL_EOF);
399: packet_put_int(c->remote_id);
400: packet_send();
401: break;
402: default:
1.28 markus 403: error("channel %d: cannot send eof for istate %d",
1.13 markus 404: c->self, c->istate);
405: break;
406: }
1.1 markus 407: }
1.3 markus 408: static void
1.13 markus 409: chan_send_close2(Channel *c)
1.6 markus 410: {
1.13 markus 411: debug("channel %d: send close", c->self);
412: if (c->ostate != CHAN_OUTPUT_CLOSED ||
413: c->istate != CHAN_INPUT_CLOSED) {
1.28 markus 414: error("channel %d: cannot send close for istate/ostate %d/%d",
1.13 markus 415: c->self, c->istate, c->ostate);
416: } else if (c->flags & CHAN_CLOSE_SENT) {
1.28 markus 417: error("channel %d: already sent close", c->self);
1.13 markus 418: } else {
419: packet_start(SSH2_MSG_CHANNEL_CLOSE);
420: packet_put_int(c->remote_id);
421: packet_send();
422: c->flags |= CHAN_CLOSE_SENT;
423: }
1.1 markus 424: }
1.23 markus 425:
426: /* shared */
427:
1.24 markus 428: void
429: chan_mark_dead(Channel *c)
430: {
1.26 markus 431: c->type = SSH_CHANNEL_ZOMBIE;
1.24 markus 432: }
433:
1.23 markus 434: int
435: chan_is_dead(Channel *c)
1.6 markus 436: {
1.26 markus 437: if (c->type == SSH_CHANNEL_ZOMBIE) {
438: debug("channel %d: zombie", c->self);
1.24 markus 439: return 1;
1.26 markus 440: }
1.23 markus 441: if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
442: return 0;
443: if (!compat20) {
444: debug("channel %d: is dead", c->self);
445: return 1;
446: }
447: /*
448: * we have to delay the close message if the efd (for stderr) is
449: * still active
450: */
451: if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
452: buffer_len(&c->extended) > 0)
453: #if 0
454: || ((c->extended_usage == CHAN_EXTENDED_READ) &&
455: c->efd != -1)
456: #endif
457: ) {
458: debug2("channel %d: active efd: %d len %d type %s",
459: c->self, c->efd, buffer_len(&c->extended),
460: c->extended_usage==CHAN_EXTENDED_READ ?
461: "read": "write");
462: } else {
1.13 markus 463: if (!(c->flags & CHAN_CLOSE_SENT)) {
464: chan_send_close2(c);
465: }
1.14 markus 466: if ((c->flags & CHAN_CLOSE_SENT) &&
1.13 markus 467: (c->flags & CHAN_CLOSE_RCVD)) {
1.23 markus 468: debug("channel %d: is dead", c->self);
469: return 1;
1.14 markus 470: }
1.1 markus 471: }
1.23 markus 472: return 0;
1.3 markus 473: }
1.13 markus 474:
1.3 markus 475: void
1.6 markus 476: chan_init_iostates(Channel *c)
477: {
478: c->ostate = CHAN_OUTPUT_OPEN;
479: c->istate = CHAN_INPUT_OPEN;
1.13 markus 480: c->flags = 0;
481: }
482:
483: /* init */
484: void
485: chan_init(void)
486: {
487: if (compat20) {
488: chan_rcvd_oclose = chan_rcvd_oclose2;
489: chan_read_failed = chan_read_failed_12;
490: chan_ibuf_empty = chan_ibuf_empty2;
491:
492: chan_rcvd_ieof = chan_rcvd_ieof2;
493: chan_write_failed = chan_write_failed2;
494: chan_obuf_empty = chan_obuf_empty2;
495: } else {
496: chan_rcvd_oclose = chan_rcvd_oclose1;
497: chan_read_failed = chan_read_failed_12;
498: chan_ibuf_empty = chan_ibuf_empty1;
499:
500: chan_rcvd_ieof = chan_rcvd_ieof1;
501: chan_write_failed = chan_write_failed1;
502: chan_obuf_empty = chan_obuf_empty1;
503: }
504: }
505:
506: /* helper */
507: static void
508: chan_shutdown_write(Channel *c)
509: {
510: buffer_consume(&c->output, buffer_len(&c->output));
511: if (compat20 && c->type == SSH_CHANNEL_LARVAL)
512: return;
513: /* shutdown failure is allowed if write failed already */
514: debug("channel %d: close_write", c->self);
515: if (c->sock != -1) {
516: if (shutdown(c->sock, SHUT_WR) < 0)
1.28 markus 517: debug("channel %d: chan_shutdown_write: "
518: "shutdown() failed for fd%d: %.100s",
1.13 markus 519: c->self, c->sock, strerror(errno));
520: } else {
521: if (close(c->wfd) < 0)
1.28 markus 522: log("channel %d: chan_shutdown_write: "
523: "close() failed for fd%d: %.100s",
1.13 markus 524: c->self, c->wfd, strerror(errno));
1.26 markus 525: c->wfd = -1;
1.13 markus 526: }
527: }
528: static void
529: chan_shutdown_read(Channel *c)
530: {
531: if (compat20 && c->type == SSH_CHANNEL_LARVAL)
532: return;
533: debug("channel %d: close_read", c->self);
534: if (c->sock != -1) {
535: if (shutdown(c->sock, SHUT_RD) < 0)
1.28 markus 536: error("channel %d: chan_shutdown_read: "
537: "shutdown() failed for fd%d [i%d o%d]: %.100s",
538: c->self, c->sock, c->istate, c->ostate,
539: strerror(errno));
1.13 markus 540: } else {
541: if (close(c->rfd) < 0)
1.28 markus 542: log("channel %d: chan_shutdown_read: "
543: "close() failed for fd%d: %.100s",
1.13 markus 544: c->self, c->rfd, strerror(errno));
1.26 markus 545: c->rfd = -1;
1.13 markus 546: }
1.1 markus 547: }
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