draft-ietf-tsvwg-source-quench-04.txt | draft-ietf-tsvwg-source-quench-05.txt | |||
---|---|---|---|---|
Transport Area Working Group (tsvwg) F. Gont | Transport Area Working Group (tsvwg) F. Gont | |||
Internet-Draft UTN/FRH | Internet-Draft UTN-FRH / SI6 Networks | |||
Obsoletes: 1016 (if approved) January 19, 2012 | Updates: 792, 1122, 1812 February 22, 2012 | |||
Updates: 792, 1122, 1812 | ||||
(if approved) | (if approved) | |||
Intended status: Standards Track | Intended status: Standards Track | |||
Expires: July 22, 2012 | Expires: August 25, 2012 | |||
Deprecation of ICMP Source Quench messages | Deprecation of ICMP Source Quench messages | |||
draft-ietf-tsvwg-source-quench-04.txt | draft-ietf-tsvwg-source-quench-05.txt | |||
Abstract | Abstract | |||
This document formally deprecates the use of ICMP Source Quench | This document formally deprecates the use of ICMP Source Quench | |||
messages by transport protocols, formally updating RFC 792, RFC 1122, | messages by transport protocols, formally updating RFC 792, RFC 1122, | |||
and RFC 1812. Additionally, it requests that the status of RFC 1016 | and RFC 1812. | |||
be changed to "Historic". | ||||
Status of this Memo | Status of this Memo | |||
This Internet-Draft is submitted in full conformance with the | This Internet-Draft is submitted in full conformance with the | |||
provisions of BCP 78 and BCP 79. | provisions of BCP 78 and BCP 79. | |||
Internet-Drafts are working documents of the Internet Engineering | Internet-Drafts are working documents of the Internet Engineering | |||
Task Force (IETF). Note that other groups may also distribute | Task Force (IETF). Note that other groups may also distribute | |||
working documents as Internet-Drafts. The list of current Internet- | working documents as Internet-Drafts. The list of current Internet- | |||
Drafts is at http://datatracker.ietf.org/drafts/current/. | Drafts is at http://datatracker.ietf.org/drafts/current/. | |||
Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
time. It is inappropriate to use Internet-Drafts as reference | time. It is inappropriate to use Internet-Drafts as reference | |||
material or to cite them other than as "work in progress." | material or to cite them other than as "work in progress." | |||
This Internet-Draft will expire on July 22, 2012. | This Internet-Draft will expire on August 25, 2012. | |||
Copyright Notice | Copyright Notice | |||
Copyright (c) 2012 IETF Trust and the persons identified as the | Copyright (c) 2012 IETF Trust and the persons identified as the | |||
document authors. All rights reserved. | document authors. All rights reserved. | |||
This document is subject to BCP 78 and the IETF Trust's Legal | This document is subject to BCP 78 and the IETF Trust's Legal | |||
Provisions Relating to IETF Documents | Provisions Relating to IETF Documents | |||
(http://trustee.ietf.org/license-info) in effect on the date of | (http://trustee.ietf.org/license-info) in effect on the date of | |||
publication of this document. Please review these documents | publication of this document. Please review these documents | |||
skipping to change at page 2, line 15 | skipping to change at page 2, line 13 | |||
described in the Simplified BSD License. | described in the Simplified BSD License. | |||
Table of Contents | Table of Contents | |||
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 | 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 | |||
2. ICMP Source Quench messages . . . . . . . . . . . . . . . . . . 3 | 2. ICMP Source Quench messages . . . . . . . . . . . . . . . . . . 3 | |||
3. Updating RFC 1122 . . . . . . . . . . . . . . . . . . . . . . . 4 | 3. Updating RFC 1122 . . . . . . . . . . . . . . . . . . . . . . . 4 | |||
4. Updating RFC 1812 . . . . . . . . . . . . . . . . . . . . . . . 4 | 4. Updating RFC 1812 . . . . . . . . . . . . . . . . . . . . . . . 4 | |||
5. Clarification for UDP, SCTP, and DCCP . . . . . . . . . . . . . 5 | 5. Clarification for UDP, SCTP, and DCCP . . . . . . . . . . . . . 5 | |||
6. General Advice to Transport Protocols . . . . . . . . . . . . . 5 | 6. General Advice to Transport Protocols . . . . . . . . . . . . . 5 | |||
7. Changing the status of RFC 1016 to Historic . . . . . . . . . . 5 | 7. Recommendation Regarding RFC 1016 . . . . . . . . . . . . . . . 5 | |||
8. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 | 8. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 | |||
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 | 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 | |||
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 | 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 | |||
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 | 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 | |||
11.1. Normative References . . . . . . . . . . . . . . . . . . . 6 | 11.1. Normative References . . . . . . . . . . . . . . . . . . . 7 | |||
11.2. Informative References . . . . . . . . . . . . . . . . . . 7 | 11.2. Informative References . . . . . . . . . . . . . . . . . . 7 | |||
Appendix A. Survey of support of ICMP Source Quench in some | Appendix A. Survey of support of ICMP Source Quench in some | |||
popular TCP/IP implementations . . . . . . . . . . . . 7 | popular TCP/IP implementations . . . . . . . . . . . . 8 | |||
Appendix B. Changes from previous versions of the draft (to | Appendix B. Changes from previous versions of the draft (to | |||
be removed by the RFC Editor before publishing | be removed by the RFC Editor before publishing | |||
this document as an RFC) . . . . . . . . . . . . . . . 8 | this document as an RFC) . . . . . . . . . . . . . . . 8 | |||
B.1. Changes from draft-ietf-tsvwg-source-quench-03 . . . . . . 8 | B.1. Changes from draft-ietf-tsvwg-source-quench-04 . . . . . . 8 | |||
B.2. Changes from draft-ietf-tsvwg-source-quench-02 . . . . . . 8 | B.2. Changes from draft-ietf-tsvwg-source-quench-03 . . . . . . 8 | |||
B.3. Changes from draft-ietf-tsvwg-source-quench-01 . . . . . . 8 | B.3. Changes from draft-ietf-tsvwg-source-quench-02 . . . . . . 9 | |||
B.4. Changes from draft-ietf-tsvwg-source-quench-00 . . . . . . 8 | B.4. Changes from draft-ietf-tsvwg-source-quench-01 . . . . . . 9 | |||
B.5. Changes from draft-gont-tsvwg-source-quench-01 . . . . . . 8 | B.5. Changes from draft-ietf-tsvwg-source-quench-00 . . . . . . 9 | |||
B.6. Changes from draft-gont-tsvwg-source-quench-00 . . . . . . 8 | B.6. Changes from draft-gont-tsvwg-source-quench-01 . . . . . . 9 | |||
B.7. Changes from draft-gont-tsvwg-source-quench-00 . . . . . . 9 | ||||
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9 | Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9 | |||
1. Introduction | 1. Introduction | |||
The ICMP specification [RFC0792] defined the ICMP Source Quench | The ICMP specification [RFC0792] defined the ICMP Source Quench | |||
message (type 4, code 0), which was meant as a mechanism for | message (type 4, code 0), which was meant as a mechanism for | |||
congestion control. ICMP Source Quench has been known to be an | congestion control. ICMP Source Quench has been known to be an | |||
ineffective (and unfair) antidote for congestion, and generation of | ineffective (and unfair) antidote for congestion, and generation of | |||
ICMP Source Quench messages by routers has been formally deprecated | ICMP Source Quench messages by routers has been formally deprecated | |||
by [RFC1812] since 1995. However, reaction to ICMP Source Quench | by [RFC1812] since 1995. However, reaction to ICMP Source Quench | |||
messages in transport protocols has never been formally deprecated. | messages in transport protocols has never been formally deprecated. | |||
This document formally deprecates reaction to ICMP Source Quench | This document formally deprecates reaction to ICMP Source Quench | |||
messages by transport protocols such as TCP, formally updating | messages by transport protocols such as TCP, formally updating | |||
[RFC0792], [RFC1122], and [RFC1812]. Additionally, it requests that | [RFC0792], [RFC1122], and [RFC1812]. Additionally, it provides | |||
the status of [RFC1016] be changed to "Historic". The rationale for | recommendation against the implementation of [RFC1016]. The | |||
these specification updates is: | rationale for these specification updates is: | |||
o Processing of ICMP Source Quench messages by routers has been | o Processing of ICMP Source Quench messages by routers has been | |||
deprecated for more than 20 years [RFC1812]. | deprecated for more than 20 years [RFC1812]. | |||
o Virtually all popular host implementations have removed support | o Virtually all popular host implementations have removed support | |||
for ICMP Source Quench messages since (at least) 2005 [RFC5927]. | for ICMP Source Quench messages since (at least) 2005 [RFC5927]. | |||
o Widespread deployment of ICMP filtering makes it impossible to | o Widespread deployment of ICMP filtering makes it impossible to | |||
rely on ICMP Source Quench messages for congestion control. | rely on ICMP Source Quench messages for congestion control. | |||
o The IETF has moved away from ICMP Source Quench messages for | o The IETF has moved away from ICMP Source Quench messages for | |||
congestion control (note e.g. the development of ECN [RFC3168], | congestion control (note e.g. the development of ECN [RFC3168], | |||
and the fact that ICMPv6 [RFC4443] does not even specify a Source | and the fact that ICMPv6 [RFC4443] does not even specify a Source | |||
Quench message). | Quench message). | |||
ICMP Source Quench messages are not normally seen in the | ||||
deployed Internet and were considered rare at least as far back | ||||
as 1994. [Floyd1994] | ||||
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", | The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", | |||
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this | "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this | |||
document are to be interpreted as described in RFC 2119 [RFC2119]. | document are to be interpreted as described in RFC 2119 [RFC2119]. | |||
2. ICMP Source Quench messages | 2. ICMP Source Quench messages | |||
The ICMP specification [RFC0792] defined the ICMP Source Quench | The ICMP specification [RFC0792] defined the ICMP Source Quench | |||
message (type 4, code 0), which was meant to provide a mechanism for | message (type 4, code 0), which was meant to provide a mechanism for | |||
congestion control. The Host Requirements RFC [RFC1122] stated in | congestion control. The Host Requirements RFC [RFC1122] stated in | |||
Section 4.2.3.9 that hosts MUST react to ICMP Source Quench messages | Section 4.2.3.9 that hosts MUST react to ICMP Source Quench messages | |||
skipping to change at page 5, line 35 | skipping to change at page 5, line 35 | |||
protocol instance, it MUST be silently ignored. | protocol instance, it MUST be silently ignored. | |||
The TSV WG is not aware of any use that requires processing of these | The TSV WG is not aware of any use that requires processing of these | |||
messages, and therefore expects other transports to follow the | messages, and therefore expects other transports to follow the | |||
recommendations in Section 3. Note that for IETF-specified | recommendations in Section 3. Note that for IETF-specified | |||
transports, this document formally deprecates reaction to ICMP Source | transports, this document formally deprecates reaction to ICMP Source | |||
Quench messages, and that generation of ICMP Source Quench messages | Quench messages, and that generation of ICMP Source Quench messages | |||
has been deprecated for both hosts and routers. Therefore, future | has been deprecated for both hosts and routers. Therefore, future | |||
applications can not expect to receive these messages. | applications can not expect to receive these messages. | |||
7. Changing the status of RFC 1016 to Historic | 7. Recommendation Regarding RFC 1016 | |||
This document requests the RFC Editor to change the status of | RFC 1016 [RFC1016] described an experimental approach to ICMP Source | |||
[RFC1016] to "Historic". | Quench message handling in hosts that was being thought about in | |||
1987. The IETF notes that RFC 1016 has never been on the IETF | ||||
standards-track, but for clarity and avoidance of doubt, the note | ||||
that the approach described in RFC 1016 [RFC1016] MUST NOT be | ||||
implemented. | ||||
8. Security Considerations | 8. Security Considerations | |||
ICMP Source Quench messages could be leveraged for performing blind | ICMP Source Quench messages could be leveraged for performing blind | |||
throughput-reduction attacks against TCP and similar protocols. This | throughput-reduction attacks against TCP and similar protocols. This | |||
attack vector, along with possible countermeasures, has been | attack vector, along with possible countermeasures, has been | |||
discussed in great detail in [RFC5927] and [CPNI-TCP]. | discussed in great detail in [RFC5927] and [CPNI-TCP]. Silently | |||
ignoring ICMP Source Quench messages, as specified in this document, | ||||
eliminates the aforementioned attack vector. | ||||
Even though sources "MUST NOT" send ICMP Source Quench Message, there | For current TCP implementations, receipt of an ICMP Source Quench | |||
are no known security issues that result from receipt of this message | message should not result in security issues because, as noted in | |||
because, as noted in [RFC5927] and [CPNI-TCP], virtually all current | [RFC5927] and [CPNI-TCP], virtually all current versions of popular | |||
versions of popular TCP implementations already silently ignore ICMP | TCP implementations already silently ignore ICMP Source Quench | |||
Source Quench messages. This is also the case for SCTP and DCCP | messages. This is also the case for SCTP and DCCP implementations. | |||
implementations. Receivers should not treat reception as an | ||||
exception, error or logged event. Receipt of an ICMP Source Quench | ||||
message must not be interpreted as an attempt to attack the receiver. | ||||
Silently ignoring ICMP Source Quench messages, as specified in this | Hosts, security gateways, and firewalls MUST silently discard | |||
document, eliminates the aforementioned attack vector. | received ICMP Source Quench packets and SHOULD log such drops as a | |||
security fault with at least minimal details (IP Source Address, IP | ||||
Destination Address, ICMP message type, and date/time the packet was | ||||
seen). | ||||
If deemed necessary, ICMP Source Quench messages could be filtered at | We note that security devices such as the Snort Network Intrusion | |||
firewalls. | Detection System (NIDS) has logged ICMP Source Quench messages as | |||
such for more than ten years. [Anderson2002]. | ||||
9. IANA Considerations | 9. IANA Considerations | |||
IANA is requested to mark ICMP type 4 (Source Quench) as "Deprecated" | IANA is requested to mark ICMP type 4 (Source Quench) as "Deprecated" | |||
in de ICMP Parameters registry [ICMPPARREG] with a reference to this | in de ICMP Parameters registry [ICMPPARREG] with a reference to this | |||
document. | document. | |||
10. Acknowledgements | 10. Acknowledgements | |||
The author of this document would like to thank Ran Atkinson, who | ||||
contributed text that was incorporated into this document and also | ||||
provided valuable feedback on earlier versions of this document. | ||||
The author of this document would like to thank (in alphabetical | The author of this document would like to thank (in alphabetical | |||
order) Fred Baker, David Black, Scott Bradner, James Carlson, Antonio | order) Fred Baker, David Black, Scott Bradner, James Carlson, Antonio | |||
De Simone, Wesley Eddy, Gorry Fairhurst, Alfred Hoenes, Mahesh | De Simone, Wesley Eddy, Gorry Fairhurst, Alfred Hoenes, Mahesh | |||
Jethanandani, Carlos Pignataro, Anantha Ramaiah, Randall Stewart, Dan | Jethanandani, Kathleen Moriarty, Carlos Pignataro, James Polk, | |||
Wing, and Andrew Yourtchenko, for providing valuable feedback on | Anantha Ramaiah, Randall Stewart, Dan Wing, and Andrew Yourtchenko, | |||
earlier versions of this document. | for providing valuable feedback on earlier versions of this document. | |||
This document has benefited from discussions within the TCPM Working | This document has benefited from discussions within the TCPM Working | |||
Group while working on [RFC5927]. | Group while working on [RFC5927]. | |||
11. References | 11. References | |||
11.1. Normative References | 11.1. Normative References | |||
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5, | [RFC0792] Postel, J., "Internet Control Message Protocol", STD 5, | |||
RFC 792, September 1981. | RFC 792, September 1981. | |||
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, | [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, | |||
RFC 793, September 1981. | RFC 793, September 1981. | |||
[RFC1122] Braden, R., "Requirements for Internet Hosts - | [RFC1122] Braden, R., "Requirements for Internet Hosts - | |||
Communication Layers", STD 3, RFC 1122, October 1989. | Communication Layers", STD 3, RFC 1122, October 1989. | |||
skipping to change at page 7, line 14 | skipping to change at page 7, line 26 | |||
RFC 1812, June 1995. | RFC 1812, June 1995. | |||
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | |||
Requirement Levels", BCP 14, RFC 2119, March 1997. | Requirement Levels", BCP 14, RFC 2119, March 1997. | |||
[RFC5681] Allman, M., Paxson, V., and E. Blanton, "TCP Congestion | [RFC5681] Allman, M., Paxson, V., and E. Blanton, "TCP Congestion | |||
Control", RFC 5681, September 2009. | Control", RFC 5681, September 2009. | |||
11.2. Informative References | 11.2. Informative References | |||
[Anderson2002] | ||||
Anderson, D., Fong, M., and A. Valdes, "Heterogeneous | ||||
Sensor Correlation: A Case Study of Live Traffic | ||||
Analysis", Proceedings of the 3rd Annual IEEE Information | ||||
Assurance Workshop New York, NY, USA, 2002. | ||||
[CPNI-TCP] | [CPNI-TCP] | |||
CPNI, "Security Assessment of the Transmission Control | CPNI, "Security Assessment of the Transmission Control | |||
Protocol (TCP)", 2009, <http://www.cpni.gov.uk/Docs/ | Protocol (TCP)", 2009, <http://www.cpni.gov.uk/Docs/ | |||
tn-03-09-security-assessment-TCP.pdf>. | tn-03-09-security-assessment-TCP.pdf>. | |||
[Floyd1994] | ||||
Floyd, S., "TCP and Explicit Congestion Notification", ACM | ||||
CCR Volume 24, Issue 5, 1994. | ||||
[FreeBSD] The FreeBSD Project, "http://www.freebsd.org". | [FreeBSD] The FreeBSD Project, "http://www.freebsd.org". | |||
[ICMPPARREG] | [ICMPPARREG] | |||
Internet Control Message Protocol (ICMP) Parameters, | Internet Control Message Protocol (ICMP) Parameters, | |||
"http://www.iana.org/assignments/icmp-parameters". | "http://www.iana.org/assignments/icmp-parameters". | |||
[Linux] The Linux Project, "http://www.kernel.org". | [Linux] The Linux Project, "http://www.kernel.org". | |||
[NetBSD] The NetBSD Project, "http://www.netbsd.org". | [NetBSD] The NetBSD Project, "http://www.netbsd.org". | |||
skipping to change at page 8, line 16 | skipping to change at page 8, line 36 | |||
Quench messages meant for TCP connections. This behavior has been | Quench messages meant for TCP connections. This behavior has been | |||
implemented in, at least, Linux [Linux] since 2004, and in FreeBSD | implemented in, at least, Linux [Linux] since 2004, and in FreeBSD | |||
[FreeBSD], NetBSD [NetBSD], OpenBSD [OpenBSD], and Solaris 10 since | [FreeBSD], NetBSD [NetBSD], OpenBSD [OpenBSD], and Solaris 10 since | |||
2005. Additionally, OpenSolaris [OpenSolaris] has always shipped | 2005. Additionally, OpenSolaris [OpenSolaris] has always shipped | |||
with support for ICMP Source Quench messages disabled. | with support for ICMP Source Quench messages disabled. | |||
Appendix B. Changes from previous versions of the draft (to be removed | Appendix B. Changes from previous versions of the draft (to be removed | |||
by the RFC Editor before publishing this document as an | by the RFC Editor before publishing this document as an | |||
RFC) | RFC) | |||
B.1. Changes from draft-ietf-tsvwg-source-quench-03 | B.1. Changes from draft-ietf-tsvwg-source-quench-04 | |||
o Removes request to move RFC 1016 to "Historic" status. | ||||
o Updates the Security Considerations section. | ||||
B.2. Changes from draft-ietf-tsvwg-source-quench-03 | ||||
o Added 'Obsoletes' metadata, and moved the reference to [RFC1016] | o Added 'Obsoletes' metadata, and moved the reference to [RFC1016] | |||
from the 'Normative References' to the 'Informative References'. | from the 'Normative References' to the 'Informative References'. | |||
B.2. Changes from draft-ietf-tsvwg-source-quench-02 | B.3. Changes from draft-ietf-tsvwg-source-quench-02 | |||
o Clarifies the requirements language. | o Clarifies the requirements language. | |||
B.3. Changes from draft-ietf-tsvwg-source-quench-01 | B.4. Changes from draft-ietf-tsvwg-source-quench-01 | |||
o Changes deprecation of ICMP SQ from "SHOULD NOT" to "MUST NOT" in | o Changes deprecation of ICMP SQ from "SHOULD NOT" to "MUST NOT" in | |||
response of feedback from Scott Bradner and the TSV WG. | response of feedback from Scott Bradner and the TSV WG. | |||
B.4. Changes from draft-ietf-tsvwg-source-quench-00 | B.5. Changes from draft-ietf-tsvwg-source-quench-00 | |||
o Discusses the motivation for deprecating ICMP Source Quench | o Discusses the motivation for deprecating ICMP Source Quench | |||
messages (as suggested by Anantha Ramaiah). | messages (as suggested by Anantha Ramaiah). | |||
o Incorporates IANA considerations such that ICMP Source Quench | o Incorporates IANA considerations such that ICMP Source Quench | |||
messages are deprecated in the corresponding registry. | messages are deprecated in the corresponding registry. | |||
B.5. Changes from draft-gont-tsvwg-source-quench-01 | B.6. Changes from draft-gont-tsvwg-source-quench-01 | |||
o Addresses nits and editorial changes suggested by Gorry Fairhurst. | o Addresses nits and editorial changes suggested by Gorry Fairhurst. | |||
o Added the status of Solaris and OpenSolaris to Appendix A. | o Added the status of Solaris and OpenSolaris to Appendix A. | |||
o Document resubmitted as draft-ietf. | o Document resubmitted as draft-ietf. | |||
B.6. Changes from draft-gont-tsvwg-source-quench-00 | B.7. Changes from draft-gont-tsvwg-source-quench-00 | |||
o This revision reflects the recent discussion about ICMP Source | o This revision reflects the recent discussion about ICMP Source | |||
Quench messages on the tsvwg mailing-list. A detailed list of the | Quench messages on the tsvwg mailing-list. A detailed list of the | |||
changes is available at: | changes is available at: | |||
http://www.ietf.org/mail-archive/web/tsvwg/current/msg10407.html | http://www.ietf.org/mail-archive/web/tsvwg/current/msg10407.html | |||
Author's Address | Author's Address | |||
Fernando Gont | Fernando Gont | |||
Universidad Tecnologica Nacional / Facultad Regional Haedo | UTN-FRH / SI6 Networks | |||
Evaristo Carriego 2644 | Evaristo Carriego 2644 | |||
Haedo, Provincia de Buenos Aires 1706 | Haedo, Provincia de Buenos Aires 1706 | |||
Argentina | Argentina | |||
Phone: +54 11 4650 8472 | Phone: +54 11 4650 8472 | |||
Email: fernando@gont.com.ar | Email: fgont@si6networks.com | |||
URI: http://www.gont.com.ar | URI: http://www.si6networks.com | |||
End of changes. 30 change blocks. | ||||
48 lines changed or deleted | 77 lines changed or added | |||
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