From sacadmin Fri Jun 18 09:53:54 2004 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Fri, 18 Jun 2004 12:53:12 -0400 From: James Carlson To: psarc@sac.sfbay.sun.com cc: "venugopal v. iyer" Subject: 2004/507 SCTP Partial Reliability Content-Length: 7894 I'm sponsoring this fast-track request for Venu Iyer. The timer is set to 06/25/2004. (As with just about every case these days, he's aiming at the last S10 build, and would appreciate getting any issues out in the open quickly. The RFC describes the details of what "partial reliability" does, but doesn't give a socket interface. This case aims to provide a provisional interface in advance of any standard -- and perhaps to set the standard. Thus, the intent is eventually Unstable -> Standard.) BACKGROUND PSARC 2003/586 added RFC 2960 - Stream Control Transmission Protocol (SCTP) - support in Solaris. RFC 3758 describes an extension to SCTP that provides partially reliable data services to an upper layer protocol. RFE 5048344 proposes to add this SCTP extension which requires adding a couple of flags and a new socket option to those introduced by PSARC 2003/586. The term PR-SCTP is used henceforth to refer to the functionality provided by RFC 3758. RELEASE BINDING/STABLILITY LEVEL Minor/Unstable DETAILS RFE 5048344 proposes to make the following changes: Socket Option - SCTP_PRSCTP --------------------------- Per RFC 3758 an SCTP endpoint should be able to indicate whether it wants to enable PR-SCTP or not. For this purpose a new socket option is introduced. The socket option is in addition to the existing socket options introduced by PSARC 2003/586 at the IPPROTO_SCTP level. The new socket option added by RFE 5048344 will be called SCTP_PRSCTP. An endpoint can indicate that it supports PR-SCTP by enabling this socket option, prior to establishing an association, using setsockopt() as setsockopt(sd, IPPROTO_SCTP, SCTP_PRSCTP, &onoff, sizeof (onoff)); where, sd is the socket descriptor onoff is an integer with a value of 1 (enable) or 0 (disable) An endpoint can determine if PR-SCTP is enabled using getsockopt() as getsockopt(sd, IPPROTO_SCTP, SCTP_PRSCTP, &onoff, &len) where, sd is the socket descriptor onoff is an integer which will, on return, have 1 if PR-SCTP is enabled, and 0 otherwise. len is socklen_t, initially sizeof (integer) SCTP_PRSCTP will be defined in netinet/sctp.h as: #define SCTP_PRSCTP 23 Flag for Partially Reliable Messages - MSG_PR_SCTP --------------------------------------------------- Additionally, a new flag is made available for applications to specify if a message is partially reliable. This flag will be set by an application in the sctp_sndrcvinfo ancillary data structure that will accompany the partially reliable message. Currently, PSARC 2003/586 defines the following flags: MSG_UNORDERED MSG_ABORT MSG_EOF MSG_ADDR_OVER RFE 5048344 plans to add: MSG_PR_SCTP MSG_PR_SCTP will be defined in netinet/sctp.h as: #define MSG_PR_SCTP 0x10 Flag to indicate if an association has PR-SCTP enabled - SCTP_PRSCTP_CAPABLE ---------------------------------------------------------------------------- Another flag is added which will be set by SCTP in the 'sac_flags' field in the sctp_assoc_change structure. Currently, there are no flags defined for 'sac_flags'. An SCTP_ASSOC_CHANGE event is sent by SCTP, with the sctp_assoc_change appropriately filled, to the upper layer when an association is established (if the upper layer has subscribed to this event). The sctp_assoc_change structure contains information about the association and will have SCTP_PRSCTP_CAPABLE set in 'sac_flags' if PR-SCTP is enabled on the association. SCTP_PRSCTP_CAPABLE is defined in netinet/sctp.h as: #define SCTP_PRSCTP_CAPABLE 0x01 MAN PAGE CHANGES RFE 5048497 will make corresponding man page changes for this. sctp_opt_info(3SOCKET) *** sctp_opt_info_3socket Mon Mar 8 15:12:38 2004 --- sctp_opt_info_3socket.5048344 Mon May 17 09:47:54 2004 *************** *** 102,107 **** --- 102,108 ---- MSG_ADDR_OVER MSG_ABORT MSG_EOF + MSG_PR_SCTP sinfo_ppid Default payload protocol identifier for sendmsg() sinfo_context Default context for sendmsg() *************** *** 109,117 **** The time to live in milliseconds for a message on the sending side. The message will expire if the sending ! side has not sent it within the ! specified time period. A value of 0 indicates the message does not expire. sinfo_tsn Always returned as 0. sinfo_cumtsn Always returned as 0. sinfo_assoc_id Filled in by the caller to specify --- 110,129 ---- The time to live in milliseconds for a message on the sending side. The message will expire if the sending ! side has not started the first ! transmission for this message within ! the specified time period. If the ! sending side has started the first ! transmission before the time period ! expires, the message is sent as a ! normal reliable message. A value of 0 indicates the message does not expire. + Additionally, if MSG_PR_SCTP is set + (in sinfo_flags), then the message + expires if the entire message has not + been transmitted within the time + period (even if transmission has + already started). sinfo_tsn Always returned as 0. sinfo_cumtsn Always returned as 0. sinfo_assoc_id Filled in by the caller to specify *** sctp_sendmsg_3socket Tue Mar 9 12:10:54 2004 --- sctp_sendmsg_3socket.5048344.0618 Fri Jun 18 08:41:40 2004 *************** *** 28,35 **** identifier stream_no the target stream for this message timetolive the time period, in milliseconds, after ! which the message expires if it has ! not been sent to the peer. context a value that is returned back if an error occurs on the send of this message. --- 28,39 ---- identifier stream_no the target stream for this message timetolive the time period, in milliseconds, after ! which the message expires if transmission for ! the message has not been started. If ! MSG_PR_SCTP is set in 'flags', then the ! message expires even if transmission has ! started. A value of '0' indicates that the ! message does not expire. context a value that is returned back if an error occurs on the send of this message. *************** *** 52,57 **** --- 56,71 ---- the specified association (one-to-many style SCTP socket only). + MSG_PR_SCTP This flag indicates that the message is to be treated + as a partially reliable message. The message will + expire unless the entire message as been successfully + transmitted by the time period specified in the + 'timetolive' parameter. + Note that MSG_PR_SCTP implements "timed reliability" + service for SCTP messages and this interface is + unstable since there is no common standard, as yet, + defined for this service. + RETURN VALUES sctp_sendmsg() returns the number of bytes sent, or -1 if an error occurred. SUMMARY RFE 5048344 proposes to add the functionality defined in RFC 3758. It introduces the following in order to do so: 1. A new socket option at the IPPROTO_SCTP level - 'SCTP_PRSCTP' 2. A new flag for an application to indicate if a message is partially reliable - 'MSG_PR_SCTP' 3. A new flag for SCTP to indicate (as an event) to the upper layer if PR-SCTP is enabled on an association - 'SCTP_PRSCTP_CAPABLE' All the 3 will be defined in netinet/sctp.h REFERENCES PSARC/2003/586 : Implementing SCTP in SunOS http://sac.sfbay.sun.com/Archives/CaseLog/arc/PSARC/2003/586/ RFC 2960 : Stream Control Transmission Protocol http://ietf.org/rfc/rfc2960.txt RFC 3758 : Stream Control Transmission Protocol (SCTP) Partial Reliability Extension http://www.ietf.org/rfc/rfc3758.txt RFE 5048344 : need to add Partial Reliability extension to SCTP RFE 5048497 : need man page modifications for PR-SCTP Project URL : http://snt.eng.sun.com/sctp/ From sacadmin Wed Jun 23 11:25:35 2004 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Wed, 23 Jun 2004 14:23:54 -0400 From: James Carlson To: psarc@sac.sfbay.sun.com cc: "venugopal v. iyer" Subject: Re: 2004/507 SCTP Partial Reliability Content-Length: 376 This case was approved during ARC business at today's meeting. I have deposited a copy of the final specification as 'spec.txt' in the case directory. -- James Carlson, IP Systems Group Sun Microsystems / 1 Network Drive 71.234W Vox +1 781 442 2084 MS UBUR02-212 / Burlington MA 01803-2757 42.497N Fax +1 781 442 1677