Network Working Group R. Stewart Internet-Draft Netflix, Inc. Intended status: Standards Track M. Tuexen Expires: January 4, 2016 Muenster Univ. of Appl. Sciences K. Nielsen Ericsson July 3, 2015 RFC 4960 Errata and Issues draft-tuexen-tsvwg-rfc4960-errata-01.txt Abstract This document is a compilation of issues found since the publication of RFC4960 in September 2007 based on experience with implementing, testing, and using SCTP along with the suggested fixes. This document provides deltas to RFC4960 and is organized in a time based way. The issues are listed in the order they were brought up. Because some text is changed several times the last delta in the text is the one which should be applied. In addition to the delta a description of the problem and the details of the solution are also provided. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 4, 2016. Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents Stewart, et al. Expires January 4, 2016 [Page 1] Internet-Draft RFC 4960 Errata and Issues July 2015 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Corrections to RFC 4960 . . . . . . . . . . . . . . . . . . . 3 3.1. Path Error Counter Threshold Handling . . . . . . . . . . 3 3.2. Upper Layer Protocol Shutdown Request Handling . . . . . 4 3.3. Registration of New Chunk Types . . . . . . . . . . . . . 5 3.4. Variable Parameters for INIT Chunks . . . . . . . . . . . 6 3.5. CRC32c Sample Code on 64-bit Platforms . . . . . . . . . 7 3.6. Endpoint Failure Detection . . . . . . . . . . . . . . . 8 3.7. Data Transmission Rules . . . . . . . . . . . . . . . . . 9 3.8. T1-Cookie Timer . . . . . . . . . . . . . . . . . . . . . 10 3.9. Miscellaneous Typos . . . . . . . . . . . . . . . . . . . 11 3.10. CRC32c Sample Code . . . . . . . . . . . . . . . . . . . 15 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 5. Security Considerations . . . . . . . . . . . . . . . . . . . 15 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.1. Normative References . . . . . . . . . . . . . . . . . . 16 7.2. Informative References . . . . . . . . . . . . . . . . . 16 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 1. Introduction This document contains a compilation of all defects found up until the publishing of this document for [RFC4960] specifying the Stream Control Transmission Protocol (SCTP). These defects may be of an editorial or technical nature. This document may be thought of as a companion document to be used in the implementation of SCTP to clarify errors in the original SCTP document. This document provides a history of the changes that will be compiled into a BIS document for [RFC4960]. It is structured similar to [RFC4460]. Each error will be detailed within this document in the form of: o The problem description, o The text quoted from [RFC4960], Stewart, et al. Expires January 4, 2016 [Page 2] Internet-Draft RFC 4960 Errata and Issues July 2015 o The replacement text that should be placed into an upcoming BIS document, o A description of the solution. Note that when reading this document one must use care to assure that a field or item is not updated further on within the document. Each section should be applied in sequence to the original [RFC4960] since this document is a historical record of the sequential changes that have been found necessary at various inter-op events and through discussion on the list. 2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. Corrections to RFC 4960 3.1. Path Error Counter Threshold Handling 3.1.1. Description of the Problem The handling of the 'Path.Max.Retrans' parameter is described in Section 8.2 and Section 8.3 of [RFC4960] in an Inconsistent way. Whereas Section 8.2 describes that a path is marked inactive when the path error counter exceeds the threshold, Section 8.3 says the path is marked inactive when the path error counter reaches the threshold. This issue was reported as an Errata for [RFC4960] with Errata ID 1440. 3.1.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 3] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 8.3) --------- When the value of this counter reaches the protocol parameter 'Path.Max.Retrans', the endpoint should mark the corresponding destination address as inactive if it is not so marked, and may also optionally report to the upper layer the change of reachability of this destination address. After this, the endpoint should continue HEARTBEAT on this destination address but should stop increasing the counter. --------- New text: (Section 8.3) --------- When the value of this counter exceeds the protocol parameter 'Path.Max.Retrans', the endpoint should mark the corresponding destination address as inactive if it is not so marked, and may also optionally report to the upper layer the change of reachability of this destination address. After this, the endpoint should continue HEARTBEAT on this destination address but should stop increasing the counter. 3.1.3. Solution Description The intended state change should happen when the threshold is exceeded. 3.2. Upper Layer Protocol Shutdown Request Handling 3.2.1. Description of the Problem Section 9.2 of [RFC4960] describes the handling of received SHUTDOWN chunks in the SHUTDOWN-RECEIVED state instead of the handling of shutdown requests from its upper layer in this state. This issue was reported as an Errata for [RFC4960] with Errata ID 1574. 3.2.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 4] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 9.2) --------- Once an endpoint has reached the SHUTDOWN-RECEIVED state, it MUST NOT send a SHUTDOWN in response to a ULP request, and should discard subsequent SHUTDOWN chunks. --------- New text: (Section 9.2) --------- Once an endpoint has reached the SHUTDOWN-RECEIVED state, it MUST NOT send a SHUTDOWN in response to a ULP request, and should discard subsequent ULP shutdown requests. 3.2.3. Solution Description The text never intended the SCTP endpoint to ignore SHUTDOWN chunks from its peer. If it did the endpoints could never gracefully terminate associations in some cases. 3.3. Registration of New Chunk Types 3.3.1. Description of the Problem Section 14.1 of [RFC4960] should deal with new chunk types, however, the text refers to parameter types. This issue was reported as an Errata for [RFC4960] with Errata ID 2592. 3.3.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 5] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 14.1) --------- The assignment of new chunk parameter type codes is done through an IETF Consensus action, as defined in [RFC2434]. Documentation of the chunk parameter MUST contain the following information: --------- New text: (Section 14.1) --------- The assignment of new chunk type codes is done through an IETF Consensus action, as defined in [RFC2434]. Documentation of the chunk type MUST contain the following information: 3.3.3. Solution Description Refer to chunk types as intended. 3.4. Variable Parameters for INIT Chunks 3.4.1. Description of the Problem Newlines in wrong places break the layout of the table of variable parameters for the INIT chunk in Section 3.3.2 of [RFC4960]. This issue was reported as an Errata for [RFC4960] with Errata ID 3291 and Errata ID 3804. 3.4.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 6] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 3.3.2) --------- Variable Parameters Status Type Value ------------------------------------------------------------- IPv4 Address (Note 1) Optional 5 IPv6 Address (Note 1) Optional 6 Cookie Preservative Optional 9 Reserved for ECN Capable (Note 2) Optional 32768 (0x8000) Host Name Address (Note 3) Optional 11 Supported Address Types (Note 4) Optional 12 --------- New text: (Section 3.3.2) --------- Variable Parameters Status Type Value ------------------------------------------------------------- IPv4 Address (Note 1) Optional 5 IPv6 Address (Note 1) Optional 6 Cookie Preservative Optional 9 Reserved for ECN Capable (Note 2) Optional 32768 (0x8000) Host Name Address (Note 3) Optional 11 Supported Address Types (Note 4) Optional 12 3.4.3. Solution Description Fix the formatting of the table. 3.5. CRC32c Sample Code on 64-bit Platforms 3.5.1. Description of the Problem The sample code for computing the CRC32c provided in [RFC4960] assumes that a variable of type unsigned long uses 32 bits. This is not true on some 64-bit platforms (for example the ones using LP64). This issue was reported as an Errata for [RFC4960] with Errata ID 3423. 3.5.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 7] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Appendix C) --------- unsigned long generate_crc32c(unsigned char *buffer, unsigned int length) { unsigned int i; unsigned long crc32 = ~0L; --------- New text: (Appendix C) --------- unsigned long generate_crc32c(unsigned char *buffer, unsigned int length) { unsigned int i; unsigned long crc32 = 0xffffffffL; 3.5.3. Solution Description Use 0xffffffffL instead of ~0L which gives the same value on platforms using 32 bits or 64 bits for variables of type unsigned long. 3.6. Endpoint Failure Detection 3.6.1. Description of the Problem The handling of the association error counter defined in Section 8.1 of [RFC4960] can result in an association failure even if the path used for data transmission is available, but idle. This issue was reported as an Errata for [RFC4960] with Errata ID 3788. 3.6.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 8] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 8.1) --------- An endpoint shall keep a counter on the total number of consecutive retransmissions to its peer (this includes retransmissions to all the destination transport addresses of the peer if it is multi-homed), including unacknowledged HEARTBEAT chunks. --------- New text: (Section 8.1) --------- An endpoint shall keep a counter on the total number of consecutive retransmissions to its peer (this includes data retransmissions to all the destination transport addresses of the peer if it is multi-homed), including the number of unacknowledged HEARTBEAT chunks observed on the path which currently is used for data transfer. Unacknowledged HEARTBEAT chunks observed on paths different from the path currently used for data transfer shall not increment the association error counter, as this could lead to association closure even if the path which currently is used for data transfer is available (but idle). 3.6.3. Solution Description A more refined handling for the association error counter is defined. 3.7. Data Transmission Rules 3.7.1. Description of the Problem When integrating the changes to Section 6.1 A) of [RFC2960] as described in Section 2.15.2 of [RFC4460] some text was duplicated and became the final paragraph of Section 6.1 A) of [RFC4960]. This issue was reported as an Errata for [RFC4960] with Errata ID 4071. 3.7.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 9] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 6.1 A)) --------- The sender MUST also have an algorithm for sending new DATA chunks to avoid silly window syndrome (SWS) as described in [RFC0813]. The algorithm can be similar to the one described in Section 4.2.3.4 of [RFC1122]. However, regardless of the value of rwnd (including if it is 0), the data sender can always have one DATA chunk in flight to the receiver if allowed by cwnd (see rule B below). This rule allows the sender to probe for a change in rwnd that the sender missed due to the SACK having been lost in transit from the data receiver to the data sender. --------- New text: (Section 6.1 A)) --------- The sender MUST also have an algorithm for sending new DATA chunks to avoid silly window syndrome (SWS) as described in [RFC0813]. The algorithm can be similar to the one described in Section 4.2.3.4 of [RFC1122]. 3.7.3. Solution Description Last paragraph of Section 6.1 A) removed as intended in Section 2.15.2 of [RFC4460]. 3.8. T1-Cookie Timer 3.8.1. Description of the Problem Figure 4 of [RFC4960] illustrates the SCTP association setup. However, it incorrectly shows that the T1-init timer is used in the COOKIE-ECHOED state whereas the T1-cookie timer should have been used instead. This issue was reported as an Errata for [RFC4960] with Errata ID 4400. 3.8.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 10] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 5.1.6, Figure 4) --------- COOKIE ECHO [Cookie_Z] ------\ (Start T1-init timer) \ (Enter COOKIE-ECHOED state) \---> (build TCB enter ESTABLISHED state) /---- COOKIE-ACK / (Cancel T1-init timer, <-----/ Enter ESTABLISHED state) --------- New text: (Section 5.1.6, Figure 4) --------- COOKIE ECHO [Cookie_Z] ------\ (Start T1-cookie timer) \ (Enter COOKIE-ECHOED state) \---> (build TCB enter ESTABLISHED state) /---- COOKIE-ACK / (Cancel T1-cookie timer, <---/ Enter ESTABLISHED state) 3.8.3. Solution Description Change the figure such that the T1-cookie timer is used instead of the T1-init timer. 3.9. Miscellaneous Typos 3.9.1. Description of the Problem While processing [RFC4960] some typos were not catched. 3.9.2. Text Changes to the Document Stewart, et al. Expires January 4, 2016 [Page 11] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 1.6) --------- Transmission Sequence Numbers wrap around when they reach 2**32 - 1. That is, the next TSN a DATA chunk MUST use after transmitting TSN = 2*32 - 1 is TSN = 0. --------- New text: (Section 1.6) --------- Transmission Sequence Numbers wrap around when they reach 2**32 - 1. That is, the next TSN a DATA chunk MUST use after transmitting TSN = 2**32 - 1 is TSN = 0. --------- Old text: (Section 3.3.10.9) --------- No User Data: This error cause is returned to the originator of a DATA chunk if a received DATA chunk has no user data. --------- New text: (Section 3.3.10.9) --------- No User Data: This error cause is returned to the originator of a DATA chunk if a received DATA chunk has no user data. Stewart, et al. Expires January 4, 2016 [Page 12] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 6.7, Figure 9) --------- Endpoint A Endpoint Z {App sends 3 messages; strm 0} DATA [TSN=6,Strm=0,Seq=2] ---------- -----> (ack delayed) (Start T3-rtx timer) DATA [TSN=7,Strm=0,Seq=3] --------> X (lost) DATA [TSN=8,Strm=0,Seq=4] ---------------> (gap detected, immediately send ack) /----- SACK [TSN Ack=6,Block=1, / Start=2,End=2] <-----/ (remove 6 from out-queue, and mark 7 as "1" missing report) --------- New text: (Section 6.7, Figure 9) --------- Endpoint A Endpoint Z {App sends 3 messages; strm 0} DATA [TSN=6,Strm=0,Seq=2] ---------------> (ack delayed) (Start T3-rtx timer) DATA [TSN=7,Strm=0,Seq=3] --------> X (lost) DATA [TSN=8,Strm=0,Seq=4] ---------------> (gap detected, immediately send ack) /----- SACK [TSN Ack=6,Block=1, / Strt=2,End=2] <-----/ (remove 6 from out-queue, and mark 7 as "1" missing report) Stewart, et al. Expires January 4, 2016 [Page 13] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Section 6.10) --------- An endpoint bundles chunks by simply including multiple chunks in one outbound SCTP packet. The total size of the resultant IP datagram, including the SCTP packet and IP headers, MUST be less that or equal to the current Path MTU. --------- New text: (Section 6.10) --------- An endpoint bundles chunks by simply including multiple chunks in one outbound SCTP packet. The total size of the resultant IP datagram, including the SCTP packet and IP headers, MUST be less that or equal to the current Path MTU. --------- Old text: (Section 10.1) --------- o Receive Unacknowledged Message Format: RECEIVE_UNACKED(data retrieval id, buffer address, buffer size, [,stream id] [, stream sequence number] [,partial flag] [,payload protocol-id]) --------- New text: (Section 10.1) --------- O Receive Unacknowledged Message Format: RECEIVE_UNACKED(data retrieval id, buffer address, buffer size, [,stream id] [, stream sequence number] [,partial flag] [,payload protocol-id]) Stewart, et al. Expires January 4, 2016 [Page 14] Internet-Draft RFC 4960 Errata and Issues July 2015 --------- Old text: (Appendix C) --------- ICMP2) An implementation MAY ignore all ICMPv6 messages where the type field is not "Destination Unreachable", "Parameter Problem",, or "Packet Too Big". --------- New text: (Appendix C) --------- ICMP2) An implementation MAY ignore all ICMPv6 messages where the type field is not "Destination Unreachable", "Parameter Problem", or "Packet Too Big". 3.9.3. Solution Description Typos fixed. 3.10. CRC32c Sample Code 3.10.1. Description of the Problem The CRC32c computation is described in Appendix B of [RFC4960]. However, the corresponding sample code and its explanation appears at the end of Appendix C, which deals with ICMP handling. 3.10.2. Text Changes to the Document Move the sample code related to CRC32c computation and its explanation from the end of Appendix C to the end of Appendix B. 3.10.3. Solution Description Text moved to the appropriate location. 4. IANA Considerations This documents does not require any actions from IANA. 5. Security Considerations This document does not add any security considerations to those given in [RFC4960]. Stewart, et al. Expires January 4, 2016 [Page 15] Internet-Draft RFC 4960 Errata and Issues July 2015 6. Acknowledgments The authors wish to thank Pontus Andersson, Eric W. Biederman, Jeff Morriss, Tom Petch, Julien Pourtet, and Maxim Proshin for their invaluable comments. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4960] Stewart, R., "Stream Control Transmission Protocol", RFC 4960, September 2007. 7.2. Informative References [RFC2960] Stewart, R., Xie, Q., Morneault, K., Sharp, C., Schwarzbauer, H., Taylor, T., Rytina, I., Kalla, M., Zhang, L., and V. Paxson, "Stream Control Transmission Protocol", RFC 2960, October 2000. [RFC4460] Stewart, R., Arias-Rodriguez, I., Poon, K., Caro, A., and M. Tuexen, "Stream Control Transmission Protocol (SCTP) Specification Errata and Issues", RFC 4460, April 2006. Authors' Addresses Randall R. Stewart Netflix, Inc. Chapin, SC 29036 United States Email: randall@lakerest.net Michael Tuexen Muenster University of Applied Sciences Stegerwaldstrasse 39 48565 Steinfurt Germany Email: tuexen@fh-muenster.de Stewart, et al. Expires January 4, 2016 [Page 16] Internet-Draft RFC 4960 Errata and Issues July 2015 Karen E. E. Nielsen Ericsson Kistavaegen 25 Stockholm 164 80 Sweden Email: karen.nielsen@tieto.com Stewart, et al. Expires January 4, 2016 [Page 17]