284 lines
7.7 KiB
Plaintext
284 lines
7.7 KiB
Plaintext
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Network Working Group G. Malkin
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Request for Commments: 2349 Bay Networks
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Updates: 1350 A. Harkin
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Obsoletes: 1784 Hewlett Packard Co.
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Category: Standards Track May 1998
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TFTP Timeout Interval and Transfer Size Options
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Status of this Memo
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This document specifies an Internet standards track protocol for the
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Internet community, and requests discussion and suggestions for
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improvements. Please refer to the current edition of the "Internet
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Official Protocol Standards" (STD 1) for the standardization state
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and status of this protocol. Distribution of this memo is unlimited.
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Copyright Notice
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Copyright (C) The Internet Society (1998). All Rights Reserved.
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Abstract
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The Trivial File Transfer Protocol [1] is a simple, lock-step, file
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transfer protocol which allows a client to get or put a file onto a
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remote host.
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This document describes two TFTP options. The first allows the client
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and server to negotiate the Timeout Interval. The second allows the
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side receiving the file to determine the ultimate size of the
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transfer before it begins. The TFTP Option Extension mechanism is
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described in [2].
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Timeout Interval Option Specification
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The TFTP Read Request or Write Request packet is modified to include
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the timeout option as follows:
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+-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
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| opc |filename| 0 | mode | 0 | timeout| 0 | #secs | 0 |
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+-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
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opc
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The opcode field contains either a 1, for Read Requests, or 2,
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for Write Requests, as defined in [1].
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Malkin & Harkin Standards Track [Page 1]
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RFC 2349 TFTP Timeout Interval and Transfer Size Options May 1998
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filename
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The name of the file to be read or written, as defined in [1].
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This is a NULL-terminated field.
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mode
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The mode of the file transfer: "netascii", "octet", or "mail",
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as defined in [1]. This is a NULL-terminated field.
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timeout
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The Timeout Interval option, "timeout" (case in-sensitive).
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This is a NULL-terminated field.
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#secs
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The number of seconds to wait before retransmitting, specified
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in ASCII. Valid values range between "1" and "255" seconds,
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inclusive. This is a NULL-terminated field.
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For example:
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+-------+--------+---+--------+---+--------+---+-------+---+
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| 1 | foobar | 0 | octet | 0 | timeout| 0 | 1 | 0 |
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+-------+--------+---+--------+---+--------+---+-------+---+
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is a Read Request, for the file named "foobar", in octet (binary)
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transfer mode, with a timeout interval of 1 second.
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If the server is willing to accept the timeout option, it sends an
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Option Acknowledgment (OACK) to the client. The specified timeout
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value must match the value specified by the client.
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Transfer Size Option Specification
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The TFTP Read Request or Write Request packet is modified to include
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the tsize option as follows:
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+-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
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| opc |filename| 0 | mode | 0 | tsize | 0 | size | 0 |
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+-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
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opc
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The opcode field contains either a 1, for Read Requests, or 2,
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for Write Requests, as defined in [1].
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filename
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The name of the file to be read or written, as defined in [1].
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This is a NULL-terminated field.
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Malkin & Harkin Standards Track [Page 2]
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RFC 2349 TFTP Timeout Interval and Transfer Size Options May 1998
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mode
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The mode of the file transfer: "netascii", "octet", or "mail",
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as defined in [1]. This is a NULL-terminated field.
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tsize
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The Transfer Size option, "tsize" (case in-sensitive). This is
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a NULL-terminated field.
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size
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The size of the file to be transfered. This is a NULL-
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terminated field.
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For example:
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+-------+--------+---+--------+---+--------+---+--------+---+
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| 2 | foobar | 0 | octet | 0 | tsize | 0 | 673312 | 0 |
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+-------+--------+---+--------+---+--------+---+--------+---+
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is a Write Request, with the 673312-octet file named "foobar", in
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octet (binary) transfer mode.
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In Read Request packets, a size of "0" is specified in the request
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and the size of the file, in octets, is returned in the OACK. If the
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file is too large for the client to handle, it may abort the transfer
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with an Error packet (error code 3). In Write Request packets, the
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size of the file, in octets, is specified in the request and echoed
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back in the OACK. If the file is too large for the server to handle,
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it may abort the transfer with an Error packet (error code 3).
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Security Considerations
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The basic TFTP protocol has no security mechanism. This is why it
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has no rename, delete, or file overwrite capabilities. This document
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does not add any security to TFTP; however, the specified extensions
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do not add any additional security risks.
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References
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[1] Sollins, K., "The TFTP Protocol (Revision 2)", STD 33, RFC 1350,
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October 92.
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[2] Malkin, G., and A. Harkin, "TFTP Option Extension", RFC 2347,
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May 1998.
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Malkin & Harkin Standards Track [Page 3]
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RFC 2349 TFTP Timeout Interval and Transfer Size Options May 1998
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Authors' Addresses
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Gary Scott Malkin
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Bay Networks
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8 Federal Street
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Billerica, MA 01821
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Phone: (978) 916-4237
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EMail: gmalkin@baynetworks.com
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Art Harkin
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Internet Services Project
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Information Networks Division
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19420 Homestead Road MS 43LN
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Cupertino, CA 95014
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Phone: (408) 447-3755
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EMail: ash@cup.hp.com
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Malkin & Harkin Standards Track [Page 4]
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RFC 2349 TFTP Timeout Interval and Transfer Size Options May 1998
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Full Copyright Statement
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Copyright (C) The Internet Society (1998). All Rights Reserved.
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This document and translations of it may be copied and furnished to
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others, and derivative works that comment on or otherwise explain it
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or assist in its implementation may be prepared, copied, published
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and distributed, in whole or in part, without restriction of any
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kind, provided that the above copyright notice and this paragraph are
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included on all such copies and derivative works. However, this
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document itself may not be modified in any way, such as by removing
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the copyright notice or references to the Internet Society or other
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Internet organizations, except as needed for the purpose of
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developing Internet standards in which case the procedures for
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copyrights defined in the Internet Standards process must be
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followed, or as required to translate it into languages other than
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English.
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The limited permissions granted above are perpetual and will not be
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revoked by the Internet Society or its successors or assigns.
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This document and the information contained herein is provided on an
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"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
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TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
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BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
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HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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Malkin & Harkin Standards Track [Page 5]
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