SIPCLF G. Salgueiro Internet-Draft Cisco Systems Intended status: Standards Track V. Gurbani Expires: September 15, 2011 Bell Labs, Alcatel-Lucent A. B. Roach Tekelec March 14, 2011 Format for the Session Initiation Protocol (SIP) Common Log Format (CLF) draft-ietf-sipclf-format-01 Abstract The SIPCLF Workgroup has defined a common log format framework for Session Initiation Protocol (SIP) servers. This common log format mimics the wildly successful event logging mechanism found in well- known web servers like Apache and web proxies like Squid. This document proposes an indexed text encoding format for the SIP Common Log Format (CLF) that retains the key advantages of a text-based format, while significantly increasing processing performance over a purely text-based implementation. This file format adheres to the SIP CLF data model and provides an effective encoding scheme for all mandatory and optional fields that appear in a SIP CLF record. 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 September 15, 2011. Copyright Notice Copyright (c) 2011 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 Salgueiro, et al. Expires September 15, 2011 [Page 1] Internet-Draft Format for SIP CLF March 2011 Provisions Relating to IETF Documents (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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Document Conventions . . . . . . . . . . . . . . . . . . . . . 4 4. Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. Index Pointers . . . . . . . . . . . . . . . . . . . . . . 8 4.2. Mandatory Fields . . . . . . . . . . . . . . . . . . . . . 10 4.3. Optional Fields . . . . . . . . . . . . . . . . . . . . . 13 4.3.1. Pre-Defined Optional Fields . . . . . . . . . . . . . 14 4.3.2. Vendor-Specific Optional Fields . . . . . . . . . . . 16 5. Example SIP CLF Record . . . . . . . . . . . . . . . . . . . . 18 6. Text Tool Considerations . . . . . . . . . . . . . . . . . . . 20 7. Security Considerations . . . . . . . . . . . . . . . . . . . 21 8. Operational Guidance . . . . . . . . . . . . . . . . . . . . . 21 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 21 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22 11.1. Normative References . . . . . . . . . . . . . . . . . . . 22 11.2. Informative References . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23 Salgueiro, et al. Expires September 15, 2011 [Page 2] Internet-Draft Format for SIP CLF March 2011 1. Introduction The extensive list of benefits and the widespread adoption of the Apache Common Log Format (CLF) has prompted the development of a functionally equivalent event logging mechanism for the Session Initiation Protocol [RFC3261] (SIP). Implementing a logging scheme for SIP is a considerable challenge. This is due in part to the fact that the behavior of a SIP entity is more complex as compared to an HTTP entity. Additionally, there are shortcomings to the purely text-based HTTP Common Log Format that need to be addressed in order to allow for real-time inspection of SIP log files. Experience with Apache Common Log Format has shown that dealing with large quantities of log data can be very processor intensive, as doing so necessarily requires reading and parsing every byte in the log file(s) of interest. An implementation independent framework for the SIP CLF has been defined in [I-D.ietf-sipclf-problem-statement]. This memo describes an indexed text file format for logging SIP messages received and sent by SIP clients, servers, and proxies that adheres to the data model presented in Section 8 of [I-D.ietf-sipclf-problem-statement]. This document defines a format that is no more difficult to generate by logging entities, while being radically faster to process. In particular, the format is optimized for both rapidly scanning through log records, as well as quickly locating commonly accessed data fields. Further, the format proposed by this document retains the key advantage of being human readable and able to be processed using the various Unix text processing tools, such as sed, awk, perl, cut, and grep. 2. Terminology 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]. [RFC3261] defines additional terms used in this document that are specific to the SIP domain such as "proxy"; "registrar"; "redirect server"; "user agent server" or "UAS"; "user agent client" or "UAC"; "back-to-back user agent" or "B2BUA"; "dialog"; "transaction"; "server transaction". This document uses the term "SIP Server" that is defined to include the following SIP entities: user agent server, registrar, redirect server, a SIP proxy in the role of user agent server, and a B2BUA in Salgueiro, et al. Expires September 15, 2011 [Page 3] Internet-Draft Format for SIP CLF March 2011 the role of a user agent server. The reader is expected to be familiar with the terminology and concepts defined in [I-D.ietf-sipclf-problem-statement]. 3. Document Conventions This document defines the logging syntax for the SIP CLF. This syntax is demonstrated through the use of various examples. The formatting described here does not permit these examples to be unambiguously rendered due to the constraints imposed by the formatting rules for Internet-Drafts. To avoid ambiguity and to meet the Internet-Draft layout requirements this document uses the markup convention established in [RFC4475]. For the sake of clarity and completeness, the entire text defining this markup convention from Section 2.1 of [RFC4475] is quoted below: Several of these examples contain unfolded lines longer than 72 characters. These are captured between tags. The single unfolded line is reconstructed by directly concatenating all lines appearing between the tags (discarding any line feeds or carriage returns). There will be no whitespace at the end of lines. Any whitespace appearing at a fold-point will appear at the beginning of a line. The following represent the same string of bits: Header-name: first value, reallylongsecondvalue, third value Header-name: first value, reallylongsecondvalue , third value Header-name: first value, reallylong second value, third value Note that this is NOT SIP header-line folding, where different strings of bits have equivalent meaning. Salgueiro, et al. Expires September 15, 2011 [Page 4] Internet-Draft Format for SIP CLF March 2011 The ip addresses used in the examples in this document adhere to the best practices outlined in [RFC5735] and correspond to the documentation address block 192.0.2.0/24 (TEST-NET-1) as described in [RFC5737]. 4. Format The Common Log Format for the Session Initiation Protocol [I-D.ietf-sipclf-problem-statement] defines a data model to which this logging format format adheres. Each SIP CLF record MUST consist of all the mandatory data model elements outlined in Section 8.1 of [I-D.ietf-sipclf-problem-statement]. All SIP CLF records MUST have the following format: 0 7 8 15 16 23 24 31 +-----------+-----------+-----------+-----------+ | Version | Record Length | 0 - 3 +-----------+-----------+-----------+-----------+ | Record Length (cont) | 0x2C | 4 - 7 +-----------+-----------+-----------+-----------+ | Flags Field | 0x2C | 8 - 11 +-----------+-----------+-----------+-----------+ | CSeq Pointer (Hex) | 12 - 15 +-----------+-----------+-----------+-----------+ | Response Status-Code Pointer (Hex) | 16 - 19 +-----------+-----------+-----------+-----------+ | R-URI Pointer (Hex) | 20 - 23 +-----------+-----------+-----------+-----------+ | Destination IP address:port Pointer (Hex) | 24 - 27 +-----------+-----------+-----------+-----------+ | Source IP address:port Pointer (Hex) | 28 - 31 +-----------+-----------+-----------+-----------+ | To URI Pointer (Hex) | 32 - 35 +-----------+-----------+-----------+-----------+ | To Tag Pointer (Hex) | 36 - 39 +-----------+-----------+-----------+-----------+ | From URI Pointer (Hex) | 40 - 43 +-----------+-----------+-----------+-----------+ | From Tag Pointer (Hex) | 44 - 47 +-----------+-----------+-----------+-----------+ | Call-Id Pointer (Hex) | 48 - 51 +-----------+-----------+-----------+-----------+ | Server-Txn Pointer (Hex) | 52 - 55 +-----------+-----------+-----------+-----------+ | Client-Txn Pointer (Hex) | 56 - 59 Salgueiro, et al. Expires September 15, 2011 [Page 5] Internet-Draft Format for SIP CLF March 2011 +-----------+-----------+-----------+-----------+ | TLV Start Pointer (Hex) | 60 - 63 +-----------+-----------+-----------+-----------+ | 0x0A | | 64 - 67 +-----------+ + | Timestamp | 68 - 71 + +-----------+ | | 0x2E | 72 - 75 +-----------+-----------+-----------+-----------+ | Fractional Seconds | 0x09 | 76 - 79 +-----------+-----------+-----------+-----------+ | | | | | Mandatory Fields (variable length) | | | | | +-----------+-----------+-----------+-----------+\ | 0x09 | Tag (Hex) | \ +-----------+-----------+-----------+-----------+ \ Repeated | Tag (cont)| 0x2C | Length (Hex) | \ as many +-----------+-----------+-----------+-----------+ > times as | Length (cont) | 0x2C | | / necessary +-----------+-----------+-----------+ + / | Value (variable length) | / +-----------+-----------+-----------+-----------+/ | 0x09 | |\ +-----------+ | \ | Vendor-ID (variable length) | \ + +-----------+-----------+-----------+ \ Repeated | | 0x2C | Length (Hex) | \ as many +-----------+-----------+-----------+-----------+ / times as | Length (cont) | 0x2C | | / necessary +-----------+-----------+-----------+ + / | Value (variable length) | / +-----------+-----------+-----------+-----------+/ | 0x0A | +-----------+ Figure 1: SIP Common Log Format The format presented in Figure 1 is for a single SIP CLF log entry. While there is no actual subdivision in practice, this format can be logically subdivided into the following three distinct components: Salgueiro, et al. Expires September 15, 2011 [Page 6] Internet-Draft Format for SIP CLF March 2011 1. Index Pointers - The first 64-bytes of this format. This portion is primarily composed of a list of pointers that indicate the beginning of both the variable length mandatory and optional fields that are logged as part of this record. These pointers are implemented as a mechanism to improve processing of these records and to allow a reader to expeditiously skip right to the desired field without unnecessarily going through the entire record. This logical subdivision within the SIP CLF format will be referenced in this document with the tag. 2. Mandatory Fields - The next logical grouping in this format is a tab delimited listing of the mandatory fields as described in Section 8.1 of [I-D.ietf-sipclf-problem-statement] and in the order listed in . This logical subdivision within the SIP CLF format will be referenced in this document with the tag. 3. Optional Fields - The last logical component MAY be present as it is an OPTIONAL extension to the SIP CLF format. Its purpose is to provide flexibility to the developer of this SIP CLF to log any desired fields not included in . This includes SIP bodies and any vendor-specific extensions. This logical subdivision within the SIP CLF format will be referenced in this document with the tag. This logical structure of the SIP CLF record format can be graphically represented as shown in Figure 2 below: Figure 2: Logical Structure of the SIP CLF Record Note that Figure 1 and Figure 2 plus the terminating line-feed are different representations of the same format but are functionally equivalent. In the following sections note that indications of "hexadecimal encoded" indicate that the value is to be written out in human- readable base-16 numbers using the ASCII characters 0x30 through 0x39 ('0' through '9') and 0x41 through 0x46 ('A' through 'F'). Similarly, indications of "decimal encoded" indicate that the value is to be written out in human readable base-10 number using the ASCII characters 0x30 through 0x39 ('0' through '9'). In both encodings, numbers always take up the number of bytes indicated, and are padded Salgueiro, et al. Expires September 15, 2011 [Page 7] Internet-Draft Format for SIP CLF March 2011 on the left with ASCII '0' characters to fill the entire space. 4.1. Index Pointers The portion of the SIP CLF record (shown in Figure 3) is a 64-byte header that indicates meta-data about the record. 0 7 8 15 16 23 24 31 +-----------+-----------+-----------+-----------+ | Version | Record Length | 0 - 3 +-----------+-----------+-----------+-----------+ | Record Length (cont) | 0x2C | 4 - 7 +-----------+-----------+-----------+-----------+ | Flags Field | 0x2C | 8 - 11 +-----------+-----------+-----------+-----------+ | CSeq Pointer (Hex) | 12 - 15 +-----------+-----------+-----------+-----------+ | Response Status-Code Pointer (Hex) | 16 - 19 +-----------+-----------+-----------+-----------+ | R-URI Pointer (Hex) | 20 - 23 +-----------+-----------+-----------+-----------+ | Destination IP address:port Pointer (Hex) | 24 - 27 +-----------+-----------+-----------+-----------+ | Source IP address:port Pointer (Hex) | 28 - 31 +-----------+-----------+-----------+-----------+ | To URI Pointer (Hex) | 32 - 35 +-----------+-----------+-----------+-----------+ | To Tag Pointer (Hex) | 36 - 39 +-----------+-----------+-----------+-----------+ | From URI Pointer (Hex) | 40 - 43 +-----------+-----------+-----------+-----------+ | From Tag Pointer (Hex) | 44 - 47 +-----------+-----------+-----------+-----------+ | Call-Id Pointer (Hex) | 48 - 51 +-----------+-----------+-----------+-----------+ | Server-Txn Pointer (Hex) | 52 - 55 +-----------+-----------+-----------+-----------+ | Client-Txn Pointer (Hex) | 56 - 59 +-----------+-----------+-----------+-----------+ | TLV Start Pointer (Hex) | 60 - 63 +-----------+-----------+-----------+-----------+ Figure 3: Index Pointers Salgueiro, et al. Expires September 15, 2011 [Page 8] Internet-Draft Format for SIP CLF March 2011 The fields that make up are described below: Version (1 byte): 0x41 for this document; hexadecimal encoded. Record Length (6 bytes): Hexadecimal encoded total length of this log record, including "Version", "Record Length", "Flags" fields and terminating line-feed. Flags Field (3 bytes): byte 1 - Request/Response flag R = request r = response byte 2 - Retransmission flag o = original transmission d = duplicate transmission s = server is stateless [i.e., retransmissions are not detected] byte 3 - Sent/Received flag u = received UDP mesage t = received TCP mesage l = received TLS mesage U = sent UDP mesage T = sent TCP mesage L = sent TLS mesage Bytes 12 through 59 contain hexadecimal encoded pointers that point to the starting location of each of the variable-length mandatory fields. Note that there are no delimiters between these pointer values -- they are packed together as a single, 52-character hexadecimal encoded string. The "Pointer" fields indicate absolute byte values within the record, and MUST be >=80. They point to the start of the corresponding value within the portion. A description of each of the mandatory fields that these pointer values point to can be found in Section 4.2. TLV Start Pointer: This final pointer indicates the location within the SIP CLF record where the OPTIONAL Tag/Length/Value (TLV) groups of begin, if present. The "TLV Start Pointer" points to the ASCII tab (0x09) character for the first entry in the portion. If the OPTIONAL TLV groups are not implemented, then the "TLV Start Pointer" field MUST be set to zero (0x0000). Salgueiro, et al. Expires September 15, 2011 [Page 9] Internet-Draft Format for SIP CLF March 2011 4.2. Mandatory Fields The portion of the SIP CLF record is shown below: 0 7 8 15 16 23 24 31 +-----------+-----------+-----------+-----------+ | 0x0A | | 64 - 67 +-----------+ + | Timestamp | 68 - 71 + +-----------+ | | 0x2E | 72 - 75 +-----------+-----------+-----------+-----------+ | Fractional Seconds | 0x09 | 76 - 79 +-----------+-----------+-----------+-----------+ | | | | | Mandatory Fields (variable length) | | | | | +-----------+-----------+-----------+-----------+ Figure 4: Mandatory Fields Following the pointers in , two fixed-length fields are encoded to specify the exact time of the log entry. As before, all fields are completely filled, pre-pending values with '0' characters as necessary. Timestamp (10 bytes): Date and time of the request or response represented as the number of seconds since the Unix epoch (i.e. seconds since midnight, January 1st, 1970, GMT). Decimal encoded. Fractional Seconds (3 bytes): Fractional seconds portion of the Timestamp field to millisecond accuracy. Decimal encoded. After the "Timestamp" and Fractional Seconds" fields are the actual values for the mandatory fields specified in Section 8.1 of [I-D.ietf-sipclf-problem-statement], which are described below: CSeq: The Command Sequence header field, including the CSeq number and method name. Response Status-Code: Set to the value of the SIP response status code for responses. Set to a single ASCII dash (0x2D) for requests. Salgueiro, et al. Expires September 15, 2011 [Page 10] Internet-Draft Format for SIP CLF March 2011 R-URI: The Request-URI in the start line (mandatory in request), including any URI parameters. Destination IP address:port The IP address of the downstream server, including the port number. The port number MUST be separated from the IP address by a single ':'. Source IP address:port The IP address of the upstream client, including the port number over which the SIP message was received. The port number MUST be separated from the IP address by a single ':'. To URI: Value of the URI in the To header field. To Tag: Value of the tag parameter (if present) in the To header field. From URI: Value of the URI in the From header field. From Tag: Value of the tag parameter in the From header field. Whilst one may question the value of the From URI in light of [RFC4474], the From URI, nonetheless, imparts some information. For one, the From tag is important and, in the case of a REGISTER request, the From URI can provide information on whether this was a third-party registration or a first-party one. Call-Id: The value of the Call-ID header field. Server-Txn: Server transaction identification code - the transaction identifier associated with the server transaction. Implementations can reuse the server transaction identifier (the topmost branch-id of the incoming request, with or without the magic cookie), or they could generate a unique identification string for a server transaction (this identifier needs to be locally unique to the server only.) This identifier is used to correlate ACKs and CANCELs to an INVITE transaction; it is also used to aid in forking. (See Section 9.4 of [I-D.ietf-sipclf-problem-statement] for usage.) Client-Txn: Client transaction identification code - this field is used to associate client transactions with a server transaction for forking proxies or B2BUAs. Upon forking, implementations can reuse the value they inserted into the topmost Via header's branch parameter, or they can generate a unique identification string for the client transaction. (See Section 9.4 of [I-D.ietf-sipclf-problem-statement] for usage.) Salgueiro, et al. Expires September 15, 2011 [Page 11] Internet-Draft Format for SIP CLF March 2011 This data MUST appear in the order listed in , and each field MUST be present. Fields are separated by a single ASCII tab character (0x09). Any tab characters present in the data to be written will be replaced by an ASCII space character (0x20) prior to being logged. Table 1 of Section 8.2 of [I-D.ietf-sipclf-problem-statement] summarizes how the mandatory fields are logged by the various SIP entities. This illustrates the fact that there are instances when a given mandatory field is not applicable for logging in the SIP CLF because it does not make sense based on the role the entity is playing in the SIP ecosystem. In such circumstances, if a given mandatory field is not present then that empty field MUST be encoded as a single horizontal dash ("-"). In the event that a field failed to parse it MUST be encoded as a single question mark ("?"). If these characters are part of a sequence of other characters, then there is no ambiguity. If the field being logged contains only one character, and that character is the literal "-", the implementation SHOULD insert an escaped %2D for that field in the SIP CLF record. Similarly, if the field contains only one character, and that character is the literal "?", the implementation SHOULD insert an escaped %3F for that field in the SIP CLF record. Salgueiro, et al. Expires September 15, 2011 [Page 12] Internet-Draft Format for SIP CLF March 2011 4.3. Optional Fields The portion of the SIP CLF record is shown below: 0 7 8 15 16 23 24 31 +-----------+-----------+-----------+-----------+\ | 0x09 | Tag (Hex) | \ +-----------+-----------+-----------+-----------+ \ Repeated | Tag (cont)| 0x2C | Length (Hex) | \ as many +-----------+-----------+-----------+-----------+ > times as | Length (cont) | 0x2C | | / necessary +-----------+-----------+-----------+ + / | Value (variable length) | / +-----------+-----------+-----------+-----------+/ | 0x09 | |\ +-----------+ | \ | Vendor-ID (variable length) | \ + +-----------+-----------+-----------+ \ Repeated | | 0x2C | Length (Hex) | \ as many +-----------+-----------+-----------+-----------+ / times as | Length (cont) | 0x2C | | / necessary +-----------+-----------+-----------+ + / | Value (variable length) | / +-----------+-----------+-----------+-----------+/ Figure 5: Optional Fields Optional fields are those SIP message elements that are not a part of the mandatory fields list detailed in Section 8.1 of [I-D.ietf-sipclf-problem-statement]. After the section, there are two OPTIONAL Tag/Length/Value groups (shown in Figure 5) that appear zero or more times. These two TLV groups provide extensibility to the SIP CLF. They allow SIP CLF implementers the flexibility to extend the logging capability of the indexed-ASCII representation beyond just the mandatory log elements described in Section 8.1 of [I-D.ietf-sipclf-problem-statement]. The location of the start of within the SIP CLF record is indicated by the "TLV Start Pointer" field in . There are two possible methods to log optional fields. One is through a pre-defined list of optional elements presented in Section 4.3.1 of this document. All other optional fields that do not appear in the list of pre-defined optional fields MUST be logged using the vendor-specific extension mechanism outlined in Section 4.3.2. Salgueiro, et al. Expires September 15, 2011 [Page 13] Internet-Draft Format for SIP CLF March 2011 4.3.1. Pre-Defined Optional Fields The pre-defined optional fields portion of is shown below: 0 7 8 15 16 23 24 31 +-----------+-----------+-----------+-----------+\ | 0x09 | Tag (Hex) | \ +-----------+-----------+-----------+-----------+ \ Repeated | Tag (cont)| 0x2C | Length (Hex) | \ as many +-----------+-----------+-----------+-----------+ > times as | Length (cont) | 0x2C | | / necessary +-----------+-----------+-----------+ + / | Value (variable length) | / +-----------+-----------+-----------+-----------+/ Figure 6: Pre-Defined Optional Fields Logging any of the pre-defined optional SIP elements below MUST be done according to the TLV format shown in Figure 6. The fields used to log these pre-defined optional fields are defined below: Tag Field (4 bytes): Indicates the type of value coded by this TLV; hexadecimal encoded. Currently defined tags are: 0x0000 - Contact Header Contains the entire value of Contact header field 0x0001 - Remote Host The DNS name of the IP address from which the message was received (if "Sent/Received flag" is set to "u,t,l"). The DNS name of the IP address to which the message is being sent (if "Sent/Received flag" is set to "U,T,L") 0x0002 - Authenticated User Logs the user name by which the user has been authenticated 0x0003 - Complete SIP Message Contains complete SIP message. Can be repeated multiple times to accommodate SIP messages that exceed 65535 bytes in length. Salgueiro, et al. Expires September 15, 2011 [Page 14] Internet-Draft Format for SIP CLF March 2011 0x0004 - SIP Message Body Logs SIP message bodies with the following body types: (1) Session Description Protocol (SDP) [RFC4566] (Content- Type: application/sdp) (2) Extensible Markup Language (XML) [W3C.REC-xml-20081126] payloads (Content-Type: application/*+xml) (3) binary (Content-Type: application/{isup,qsig}) (4) miscellaneous text content (Content-Type: message/sipfrag, message/http, text/plain, ...) In this TLV (with Tag=0x0004), the associated "Value" field is populated with the Content-Type itself plus the SIP message body separated with a linear white space (LWS) separator. In this manner, everything about all four body types is self- described using a single tag as compared to enumerating a separate tag for each body type. Additionally the corresponding "Length" field includes the SIP message body, the length of the embedded Content-Type, and the LWS separator between the MIME type and the body content. Note that binary bodies would have to be byte encoded to render them in the ASCII file. An example of an SDP body to be logged as an optional field: v=0 o=alice 2890844526 2890844526 IN IP4 host.example.com s=- c=IN IP4 host.example.com t=0 0 m=audio 49170 RTP/AVP 0 8 97 This body has a Content-Type of application/sdp and is of length of 123 including all the line-feeds. When logging this body the "Value" field is composed of the Content-Type and the body separated by a LWS, which gives it a combined length of 139 (0x8B). The TLV used to log this SIP body as an optional field would look like: Salgueiro, et al. Expires September 15, 2011 [Page 15] Internet-Draft Format for SIP CLF March 2011 0004,008B,application/sdp v=0\r\no=alice 2890844526 2890844526 IN IP4 host.example.com\r\ns=-\r\n c=IN IP4 host.example.com\r\nt=0 0\r\n m=audio 49170 RTP/AVP 0 8 97\r\n Note that the octets in the "Value" field are all logically on one line and the line-feeds are escaped using \r\n to delimit the lines. TODO: Is it necessary that we document an escape mechanism for line-feeds for both logging bodies and complete SIP messages? If we agree on \r\n we need to think about how to represent \r\n in a text-based body. Length Field (4 bytes): Indicates the length of the value coded in this TLV, hexadecimal encoded. This length does NOT include the TLV header. Value Field (0 to 65535 bytes): Contains the actual value of this TLV. As with the mandatory fields, ASCII Tab characters (0x09) are replaced with ASCII space characters (0x20). 4.3.2. Vendor-Specific Optional Fields The vendor-specific optional fields portion of is shown below: 0 7 8 15 16 23 24 31 +-----------+-----------+-----------+-----------+ | 0x09 | |\ +-----------+ | \ | Vendor-ID (variable length) | \ + +-----------+-----------+-----------+ \ Repeated | | 0x2C | Length (Hex) | \ as many +-----------+-----------+-----------+-----------+ / times as | Length (cont) | 0x2C | | / necessary +-----------+-----------+-----------+ + / | Value (variable length) | / +-----------+-----------+-----------+-----------+/ Figure 7: Vendor-Specific Optional Fields Salgueiro, et al. Expires September 15, 2011 [Page 16] Internet-Draft Format for SIP CLF March 2011 The pre-defined list of optionally logged fields is a very limited set of some of the most useful and commonly logged SIP elements that fall outside the range of the mandatory fields presented in Section 8.1 of [I-D.ietf-sipclf-problem-statement]. To make the SIP CLF fully extensible and customizable to implementers, the notion of vendor-specific optional fields is introduced. This mechanism extends the logging capabilities of SIP CLF to include any element of a SIP message that a vendor deems necessary. This vendor-specific extension to the SIP CLF has a TLV-like syntax and intentionally mimics the general format described in Section 4.2 for the pre- defined optional fields. Vendor-ID (0 to 65535 bytes): The Vendor-ID has a similar purpose as the "Tag" field defined in Section 4.3.1. That is, a unique identifier for the optional fields being logged. The optional fields logged via vendor-specific extensions MUST NOT be any of the pre-defined optional fields detailed in Section 4.3.1. Format for the Vendor-ID is similar to the second format detailed in Section 6.3.2 of the Syslog protocol [RFC5424] for SD-ID names. The syntax for the Vendor-ID is name@, e.g., "ourVendorID@32473". Formatting rules defining the Vendor-ID is quoted almost verbatim from Section 6.3.2 of [RFC5424]: The format of the part preceding the at-sign is not specified; however, these names MUST be printable US-ASCII strings, and MUST NOT contain an at-sign ('@', ABNF %d64), an equal-sign ('=', ABNF %d61), a closing brace (']', ABNF %d93), a quote- character ('"', ABNF %d34), whitespace, or control characters. The part following the at-sign MUST be a private enterprise number as specified in Section 7.2.2 of [RFC5424]. Please note that throughout this document the value of 32473 is used for all private enterprise numbers. This value has been reserved by IANA to be used as an example number in documentation according to [RFC5612]. Implementers of the Vendor-ID will need to use their own private enterprise number from the complete current list of private enterprise numbers [PEN] maintained by IANA. Usage of the Vendor-ID allows vendor-specific customization of the SIP CLF beyond those pre-defined optional fields defined in Section 4.3.1. Length Field (4 bytes): Indicates the length of only the "Value" field in this vendor-specified extension, hexadecimal encoded. Salgueiro, et al. Expires September 15, 2011 [Page 17] Internet-Draft Format for SIP CLF March 2011 Value Field (0 to 65535 bytes): Contains the actual value of this vendor-specific optional field. As with the mandatory fields, ASCII Tab characters (0x09) are replaced with ASCII space characters (0x20). 5. Example SIP CLF Record The following SIP message is an INVITE request sent by a SIP client: Salgueiro, et al. Expires September 15, 2011 [Page 18] Internet-Draft Format for SIP CLF March 2011 INVITE sip:192.0.2.10 SIP/2.0 To: Call-ID: DL70dff590c1-1079051554@example.com From: "Alice" ; tag=DL88360fa5fc;epid=0x34619b0 CSeq: 1 INVITE Max-Forwards: 70 Via: SIP/2.0/TCP 192.0.2.200:5060; branch=z9hG4bK-1f6be070c4-DL Contact: "1001" Allow: INVITE,CANCEL,ACK,OPTIONS,INFO,SUBSCRIBE,NOTIFY,BYE, MESSAGE,UPDATE,REFER Supported: replaces,norefersub User-Agent: Some Vendor Content-Type: application/sdp Content-Length: 418 v=0 o=1001 1456139204 0 IN IP4 192.0.2.200 s=- c=IN IP4 192.0.2.200 b=AS:2048 t=0 0 m=audio 13756 RTP/AVP 0 101 a=rtpmap:0 PCMU/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=x-mpdp:192.0.2.200:13756 m=video 13758 RTP/AVP 96 a=rtpmap:96 H264/90000 a=fmtp:96 profile-level-id=420015; max-mbps=47520; max-fs=1584; max-dpb=7680 a=x-mpdp:192.0.2.200:13758 Salgueiro, et al. Expires September 15, 2011 [Page 19] Internet-Draft Format for SIP CLF March 2011 Shown below is approximately how this message would appear as a single record in a SIP CLF logging file if encoded according to the syntax described in this document. Due to internet-draft conventions, this log entry has been split into seven lines, instead of the two lines that actually appear in a log file; and the tab characters have been padded out using spaces to simulate their appearance in a text terminal. A0000FC,Rou, 0051005A005C006B007B008D009C009E00B800C500E900F30000 0000000000.010 1 INVITE - sip:192.0.2.10 192.0.2.10:5060 192.0.2.200:56485 sip:192.0.2.10 - sip:1001@example.com:5060 DL88360fa5fc DL70dff590c1-1079051554@example.com server-tx A Base64 encoded version of this log entry (without the changes required to format it for an internet-draft) is shown below: begin-base64 644 clf_record QTAwMDBGQyxSb3UsMDA1MTAwNUEwMDVDMDA2QjAwN0IwMDhEMDA5QzAwOUUwMEI4 MDBDNTAwRTkwMEYzMDAwMAowMDAwMDAwMDAwLjAxMAkxIElOVklURQktCXNpcDox OTIuMC4yLjEwCTE5Mi4wLjIuMTA6NTA2MAkxOTIuMC4yLjIwMDo1NjQ4NQlzaXA6 MTkyLjAuMi4xMAktCXNpcDoxMDAxQGV4YW1wbGUuY29tOjUwNjAJREw4ODM2MGZh NWZjCURMNzBkZmY1OTBjMS0xMDc5MDUxNTU0QGV4YW1wbGUuY29tCXNlcnZlci10 eAljbGllbnQtdHgK ==== 6. Text Tool Considerations This format has been designed to allow text tools to easily process logs without needing to understand the indexing format. Index lines may be rapidly discarded by checking the first character of the line: index lines will always start with an alphabetical character, while field lines will start with a numerical character. Salgueiro, et al. Expires September 15, 2011 [Page 20] Internet-Draft Format for SIP CLF March 2011 Within a field line, script tools can quickly split fields at the tab characters. The first 12 fields are positional, and the meaning of any subsequent fields can be determined by checking the first four characters of the field. Alternately, these non-positional fields can be located using a regular expression. For example, the "Contact value" in a request can be found by searching for the perl regex /\t0000,....,([^\t]*)/. Note also that requests can be distinguished from responses by checking the third positional field -- for requests, it will always be set to "000"; any other value indicates a response. 7. Security Considerations This document does not introduce any new security considerations beyond those discussed in [I-D.ietf-sipclf-problem-statement]. 8. Operational Guidance SIP CLF log files will take up substantive amount of disk space depending on traffic volume at a processing entity and the amount of information being logged. As such, any enterprise using SIP CLF should establish operational procedures for file rollovers as appropriate to the needs of the organization. Listing such operational guidelines in this document is out of scope for this work. 9. IANA Considerations This document does not require any considerations from IANA. 10. Acknowledgements The authors of this document would like to acknowledge and thank Peter Musgrave for his support, guidance, and continued invaluable feedback. This work benefited from the discussions and invaluable input by the various members of the SIPCLF working group. These include Brian Trammell, Eric Burger, Cullen Jennings, Benoit Claise, Saverio Niccolini, Dan Burnett. Special thanks to Hadriel Kaplan, Chris Lonvick, Paul E. Jones, John Elwell for their constructive comments, suggestions, and reviews that were critical to the formulation and Salgueiro, et al. Expires September 15, 2011 [Page 21] Internet-Draft Format for SIP CLF March 2011 refinement of this draft. Thanks to Anders Nygren for his early implementation, insight, and reviews of the SIP CLF format. 11. References 11.1. Normative References [I-D.ietf-sipclf-problem-statement] Gurbani, V., Burger, E., Anjali, T., Abdelnur, H., and O. Festor, "The Common Log Format (CLF) for the Session Initiation Protocol (SIP)", draft-ietf-sipclf-problem-statement-05 (work in progress), March 2011. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. [RFC5424] Gerhards, R., "The Syslog Protocol", RFC 5424, March 2009. 11.2. Informative References [PEN] IANA, "Private Enterprise Numbers", http://www.iana.org/assignments/enterprise-numbers , 2009. [RFC4474] Peterson, J. and C. Jennings, "Enhancements for Authenticated Identity Management in the Session Initiation Protocol (SIP)", RFC 4474, August 2006. [RFC4475] Sparks, R., Hawrylyshen, A., Johnston, A., Rosenberg, J., and H. Schulzrinne, "Session Initiation Protocol (SIP) Torture Test Messages", RFC 4475, May 2006. [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, July 2006. [RFC5612] Eronen, P. and D. Harrington, "Enterprise Number for Documentation Use", RFC 5612, August 2009. [RFC5735] Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses", BCP 153, RFC 5735, January 2010. Salgueiro, et al. Expires September 15, 2011 [Page 22] Internet-Draft Format for SIP CLF March 2011 [RFC5737] Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks Reserved for Documentation", RFC 5737, January 2010. [W3C.REC-xml-20081126] Yergeau, F., Bray, T., Paoli, J., Maler, E., and C. Sperberg-McQueen, "Extensible Markup Language (XML) 1.0 (Fifth Edition)", World Wide Web Consortium Recommendation REC-xml-20081126, November 2008, . Authors' Addresses Gonzalo Salgueiro Cisco Systems 7200-12 Kit Creek Road Research Triangle Park, NC 27709 US Email: gsalguei@cisco.com Vijay Gurbani Bell Labs, Alcatel-Lucent 1960 Lucent Lane Rm 9C-533 Naperville, IL 60563 US Email: vkg@bell-labs.com Adam Roach Tekelec 17210 Campbell Rd. Suite 250 Dallas, TX 75252 US Email: adam@nostrum.com Salgueiro, et al. Expires September 15, 2011 [Page 23]