| Ben Lindstrom | 8bceffb | 2001-10-04 21:16:57 +0000 | [diff] [blame] | 1 | .\" $OpenBSD: nchan2.ms,v 1.2 2001/10/03 10:05:57 markus Exp $ |
| 2 | .\" |
| 3 | .\" Copyright (c) 2000 Markus Friedl. All rights reserved. |
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| 9 | .\" notice, this list of conditions and the following disclaimer. |
| 10 | .\" 2. Redistributions in binary form must reproduce the above copyright |
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| 14 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| Damien Miller | 33b1356 | 2000-04-04 14:38:59 +1000 | [diff] [blame] | 25 | .TL |
| 26 | OpenSSH Channel Close Protocol 2.0 Implementation |
| 27 | .SH |
| 28 | Channel Input State Diagram |
| 29 | .PS |
| 30 | reset |
| 31 | l=1 |
| 32 | s=1.2 |
| 33 | ellipsewid=s*ellipsewid |
| 34 | boxwid=s*boxwid |
| 35 | ellipseht=s*ellipseht |
| 36 | S1: ellipse "INPUT" "OPEN" |
| 37 | move right 2*l from last ellipse.e |
| 38 | S3: ellipse invis |
| 39 | move down l from last ellipse.s |
| 40 | S4: ellipse "INPUT" "CLOSED" |
| 41 | move down l from 1st ellipse.s |
| 42 | S2: ellipse "INPUT" "WAIT" "DRAIN" |
| 43 | arrow from S1.e to S4.n |
| 44 | box invis "rcvd CLOSE/" "shutdown_read" with .sw at last arrow.c |
| 45 | arrow "ibuf_empty ||" "rcvd CLOSE/" "send EOF" "" from S2.e to S4.w |
| 46 | arrow from S1.s to S2.n |
| 47 | box invis "read_failed/" "shutdown_read" with .e at last arrow.c |
| 48 | ellipse wid .9*ellipsewid ht .9*ellipseht at S4 |
| 49 | arrow "start" "" from S1.w+(-0.5,0) to S1.w |
| 50 | .PE |
| 51 | .SH |
| 52 | Channel Output State Diagram |
| 53 | .PS |
| 54 | S1: ellipse "OUTPUT" "OPEN" |
| 55 | move right 2*l from last ellipse.e |
| 56 | S3: ellipse invis |
| 57 | move down l from last ellipse.s |
| 58 | S4: ellipse "OUTPUT" "CLOSED" |
| 59 | move down l from 1st ellipse.s |
| 60 | S2: ellipse "OUTPUT" "WAIT" "DRAIN" |
| 61 | arrow from S1.e to S4.n |
| 62 | box invis "write_failed/" "shutdown_write" with .sw at last arrow.c |
| 63 | arrow "obuf_empty ||" "write_failed/" "shutdown_write" "" from S2.e to S4.w |
| 64 | arrow from S1.s to S2.n |
| 65 | box invis "rcvd EOF ||" "rcvd CLOSE/" "-" with .e at last arrow.c |
| 66 | ellipse wid .9*ellipsewid ht .9*ellipseht at S4 |
| 67 | arrow "start" "" from S1.w+(-0.5,0) to S1.w |
| 68 | .PE |
| 69 | .SH |
| 70 | Notes |
| 71 | .PP |
| 72 | The input buffer is filled with data from the socket |
| 73 | (the socket represents the local consumer/producer of the |
| 74 | forwarded channel). |
| 75 | The data is then sent over the INPUT-end (transmit-end) of the channel to the |
| 76 | remote peer. |
| 77 | Data sent by the peer is received on the OUTPUT-end (receive-end), |
| 78 | saved in the output buffer and written to the socket. |
| 79 | .PP |
| 80 | If the local protocol instance has forwarded all data on the |
| 81 | INPUT-end of the channel, it sends an EOF message to the peer. |
| 82 | .PP |
| 83 | A CLOSE message is sent to the peer if |
| 84 | both the INPUT- and the OUTOUT-half of the local |
| 85 | end of the channel are closed. |
| 86 | .PP |
| 87 | The channel can be deallocated by a protocol instance |
| 88 | if a CLOSE message he been both sent and received. |