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diff --git a/Documentation/netlabel/draft-ietf-cipso-ipsecurity-01.txt b/Documentation/netlabel/draft-ietf-cipso-ipsecurity-01.txt new file mode 100644 index 0000000..256c2c9 --- /dev/null +++ b/Documentation/netlabel/draft-ietf-cipso-ipsecurity-01.txt @@ -0,0 +1,791 @@ +IETF CIPSO Working Group +16 July, 1992 + + + + COMMERCIAL IP SECURITY OPTION (CIPSO 2.2) + + + +1. Status + +This Internet Draft provides the high level specification for a Commercial +IP Security Option (CIPSO). This draft reflects the version as approved by +the CIPSO IETF Working Group. Distribution of this memo is unlimited. + +This document is an Internet Draft. Internet Drafts are working documents +of the Internet Engineering Task Force (IETF), its Areas, and its Working +Groups. Note that other groups may also distribute working documents as +Internet Drafts. + +Internet Drafts are draft documents valid for a maximum of six months. +Internet Drafts may be updated, replaced, or obsoleted by other documents +at any time. It is not appropriate to use Internet Drafts as reference +material or to cite them other than as a "working draft" or "work in +progress." + +Please check the I-D abstract listing contained in each Internet Draft +directory to learn the current status of this or any other Internet Draft. + + + + +2. Background + +Currently the Internet Protocol includes two security options. One of +these options is the DoD Basic Security Option (BSO) (Type 130) which allows +IP datagrams to be labeled with security classifications. This option +provides sixteen security classifications and a variable number of handling +restrictions. To handle additional security information, such as security +categories or compartments, another security option (Type 133) exists and +is referred to as the DoD Extended Security Option (ESO). The values for +the fixed fields within these two options are administered by the Defense +Information Systems Agency (DISA). + +Computer vendors are now building commercial operating systems with +mandatory access controls and multi-level security. These systems are +no longer built specifically for a particular group in the defense or +intelligence communities. They are generally available commercial systems +for use in a variety of government and civil sector environments. + +The small number of ESO format codes can not support all the possible +applications of a commercial security option. The BSO and ESO were +designed to only support the United States DoD. CIPSO has been designed +to support multiple security policies. This Internet Draft provides the +format and procedures required to support a Mandatory Access Control +security policy. Support for additional security policies shall be +defined in future RFCs. + + + + +Internet Draft, Expires 15 Jan 93 [PAGE 1] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + + +3. CIPSO Format + +Option type: 134 (Class 0, Number 6, Copy on Fragmentation) +Option length: Variable + +This option permits security related information to be passed between +systems within a single Domain of Interpretation (DOI). A DOI is a +collection of systems which agree on the meaning of particular values +in the security option. An authority that has been assigned a DOI +identifier will define a mapping between appropriate CIPSO field values +and their human readable equivalent. This authority will distribute that +mapping to hosts within the authority's domain. These mappings may be +sensitive, therefore a DOI authority is not required to make these +mappings available to anyone other than the systems that are included in +the DOI. + +This option MUST be copied on fragmentation. This option appears at most +once in a datagram. All multi-octet fields in the option are defined to be +transmitted in network byte order. The format of this option is as follows: + ++----------+----------+------//------+-----------//---------+ +| 10000110 | LLLLLLLL | DDDDDDDDDDDD | TTTTTTTTTTTTTTTTTTTT | ++----------+----------+------//------+-----------//---------+ + + TYPE=134 OPTION DOMAIN OF TAGS + LENGTH INTERPRETATION + + + Figure 1. CIPSO Format + + +3.1 Type + +This field is 1 octet in length. Its value is 134. + + +3.2 Length + +This field is 1 octet in length. It is the total length of the option +including the type and length fields. With the current IP header length +restriction of 40 octets the value of this field MUST not exceed 40. + + +3.3 Domain of Interpretation Identifier + +This field is an unsigned 32 bit integer. The value 0 is reserved and MUST +not appear as the DOI identifier in any CIPSO option. Implementations +should assume that the DOI identifier field is not aligned on any particular +byte boundary. + +To conserve space in the protocol, security levels and categories are +represented by numbers rather than their ASCII equivalent. This requires +a mapping table within CIPSO hosts to map these numbers to their +corresponding ASCII representations. Non-related groups of systems may + + + +Internet Draft, Expires 15 Jan 93 [PAGE 2] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + +have their own unique mappings. For example, one group of systems may +use the number 5 to represent Unclassified while another group may use the +number 1 to represent that same security level. The DOI identifier is used +to identify which mapping was used for the values within the option. + + +3.4 Tag Types + +A common format for passing security related information is necessary +for interoperability. CIPSO uses sets of "tags" to contain the security +information relevant to the data in the IP packet. Each tag begins with +a tag type identifier followed by the length of the tag and ends with the +actual security information to be passed. All multi-octet fields in a tag +are defined to be transmitted in network byte order. Like the DOI +identifier field in the CIPSO header, implementations should assume that +all tags, as well as fields within a tag, are not aligned on any particular +octet boundary. The tag types defined in this document contain alignment +bytes to assist alignment of some information, however alignment can not +be guaranteed if CIPSO is not the first IP option. + +CIPSO tag types 0 through 127 are reserved for defining standard tag +formats. Their definitions will be published in RFCs. Tag types whose +identifiers are greater than 127 are defined by the DOI authority and may +only be meaningful in certain Domains of Interpretation. For these tag +types, implementations will require the DOI identifier as well as the tag +number to determine the security policy and the format associated with the +tag. Use of tag types above 127 are restricted to closed networks where +interoperability with other networks will not be an issue. Implementations +that support a tag type greater than 127 MUST support at least one DOI that +requires only tag types 1 to 127. + +Tag type 0 is reserved. Tag types 1, 2, and 5 are defined in this +Internet Draft. Types 3 and 4 are reserved for work in progress. +The standard format for all current and future CIPSO tags is shown below: + ++----------+----------+--------//--------+ +| TTTTTTTT | LLLLLLLL | IIIIIIIIIIIIIIII | ++----------+----------+--------//--------+ + TAG TAG TAG + TYPE LENGTH INFORMATION + + Figure 2: Standard Tag Format + +In the three tag types described in this document, the length and count +restrictions are based on the current IP limitation of 40 octets for all +IP options. If the IP header is later expanded, then the length and count +restrictions specified in this document may increase to use the full area +provided for IP options. + + +3.4.1 Tag Type Classes + +Tag classes consist of tag types that have common processing requirements +and support the same security policy. The three tags defined in this +Internet Draft belong to the Mandatory Access Control (MAC) Sensitivity + + + +Internet Draft, Expires 15 Jan 93 [PAGE 3] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + +class and support the MAC Sensitivity security policy. + + +3.4.2 Tag Type 1 + +This is referred to as the "bit-mapped" tag type. Tag type 1 is included +in the MAC Sensitivity tag type class. The format of this tag type is as +follows: + ++----------+----------+----------+----------+--------//---------+ +| 00000001 | LLLLLLLL | 00000000 | LLLLLLLL | CCCCCCCCCCCCCCCCC | ++----------+----------+----------+----------+--------//---------+ + + TAG TAG ALIGNMENT SENSITIVITY BIT MAP OF + TYPE LENGTH OCTET LEVEL CATEGORIES + + Figure 3. Tag Type 1 Format + + +3.4.2.1 Tag Type + +This field is 1 octet in length and has a value of 1. + + +3.4.2.2 Tag Length + +This field is 1 octet in length. It is the total length of the tag type +including the type and length fields. With the current IP header length +restriction of 40 bytes the value within this field is between 4 and 34. + + +3.4.2.3 Alignment Octet + +This field is 1 octet in length and always has the value of 0. Its purpose +is to align the category bitmap field on an even octet boundary. This will +speed many implementations including router implementations. + + +3.4.2.4 Sensitivity Level + +This field is 1 octet in length. Its value is from 0 to 255. The values +are ordered with 0 being the minimum value and 255 representing the maximum +value. + + +3.4.2.5 Bit Map of Categories + +The length of this field is variable and ranges from 0 to 30 octets. This +provides representation of categories 0 to 239. The ordering of the bits +is left to right or MSB to LSB. For example category 0 is represented by +the most significant bit of the first byte and category 15 is represented +by the least significant bit of the second byte. Figure 4 graphically +shows this ordering. Bit N is binary 1 if category N is part of the label +for the datagram, and bit N is binary 0 if category N is not part of the +label. Except for the optimized tag 1 format described in the next section, + + + +Internet Draft, Expires 15 Jan 93 [PAGE 4] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + +minimal encoding SHOULD be used resulting in no trailing zero octets in the +category bitmap. + + octet 0 octet 1 octet 2 octet 3 octet 4 octet 5 + XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX . . . +bit 01234567 89111111 11112222 22222233 33333333 44444444 +number 012345 67890123 45678901 23456789 01234567 + + Figure 4. Ordering of Bits in Tag 1 Bit Map + + +3.4.2.6 Optimized Tag 1 Format + +Routers work most efficiently when processing fixed length fields. To +support these routers there is an optimized form of tag type 1. The format +does not change. The only change is to the category bitmap which is set to +a constant length of 10 octets. Trailing octets required to fill out the 10 +octets are zero filled. Ten octets, allowing for 80 categories, was chosen +because it makes the total length of the CIPSO option 20 octets. If CIPSO +is the only option then the option will be full word aligned and additional +filler octets will not be required. + + +3.4.3 Tag Type 2 + +This is referred to as the "enumerated" tag type. It is used to describe +large but sparsely populated sets of categories. Tag type 2 is in the MAC +Sensitivity tag type class. The format of this tag type is as follows: + ++----------+----------+----------+----------+-------------//-------------+ +| 00000010 | LLLLLLLL | 00000000 | LLLLLLLL | CCCCCCCCCCCCCCCCCCCCCCCCCC | ++----------+----------+----------+----------+-------------//-------------+ + + TAG TAG ALIGNMENT SENSITIVITY ENUMERATED + TYPE LENGTH OCTET LEVEL CATEGORIES + + Figure 5. Tag Type 2 Format + + +3.4.3.1 Tag Type + +This field is one octet in length and has a value of 2. + + +3.4.3.2 Tag Length + +This field is 1 octet in length. It is the total length of the tag type +including the type and length fields. With the current IP header length +restriction of 40 bytes the value within this field is between 4 and 34. + + +3.4.3.3 Alignment Octet + +This field is 1 octet in length and always has the value of 0. Its purpose +is to align the category field on an even octet boundary. This will + + + +Internet Draft, Expires 15 Jan 93 [PAGE 5] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + +speed many implementations including router implementations. + + +3.4.3.4 Sensitivity Level + +This field is 1 octet in length. Its value is from 0 to 255. The values +are ordered with 0 being the minimum value and 255 representing the +maximum value. + + +3.4.3.5 Enumerated Categories + +In this tag, categories are represented by their actual value rather than +by their position within a bit field. The length of each category is 2 +octets. Up to 15 categories may be represented by this tag. Valid values +for categories are 0 to 65534. Category 65535 is not a valid category +value. The categories MUST be listed in ascending order within the tag. + + +3.4.4 Tag Type 5 + +This is referred to as the "range" tag type. It is used to represent +labels where all categories in a range, or set of ranges, are included +in the sensitivity label. Tag type 5 is in the MAC Sensitivity tag type +class. The format of this tag type is as follows: + ++----------+----------+----------+----------+------------//-------------+ +| 00000101 | LLLLLLLL | 00000000 | LLLLLLLL | Top/Bottom | Top/Bottom | ++----------+----------+----------+----------+------------//-------------+ + + TAG TAG ALIGNMENT SENSITIVITY CATEGORY RANGES + TYPE LENGTH OCTET LEVEL + + Figure 6. Tag Type 5 Format + + +3.4.4.1 Tag Type + +This field is one octet in length and has a value of 5. + + +3.4.4.2 Tag Length + +This field is 1 octet in length. It is the total length of the tag type +including the type and length fields. With the current IP header length +restriction of 40 bytes the value within this field is between 4 and 34. + + +3.4.4.3 Alignment Octet + +This field is 1 octet in length and always has the value of 0. Its purpose +is to align the category range field on an even octet boundary. This will +speed many implementations including router implementations. + + + + + +Internet Draft, Expires 15 Jan 93 [PAGE 6] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + +3.4.4.4 Sensitivity Level + +This field is 1 octet in length. Its value is from 0 to 255. The values +are ordered with 0 being the minimum value and 255 representing the maximum +value. + + +3.4.4.5 Category Ranges + +A category range is a 4 octet field comprised of the 2 octet index of the +highest numbered category followed by the 2 octet index of the lowest +numbered category. These range endpoints are inclusive within the range of +categories. All categories within a range are included in the sensitivity +label. This tag may contain a maximum of 7 category pairs. The bottom +category endpoint for the last pair in the tag MAY be omitted and SHOULD be +assumed to be 0. The ranges MUST be non-overlapping and be listed in +descending order. Valid values for categories are 0 to 65534. Category +65535 is not a valid category value. + + +3.4.5 Minimum Requirements + +A CIPSO implementation MUST be capable of generating at least tag type 1 in +the non-optimized form. In addition, a CIPSO implementation MUST be able +to receive any valid tag type 1 even those using the optimized tag type 1 +format. + + +4. Configuration Parameters + +The configuration parameters defined below are required for all CIPSO hosts, +gateways, and routers that support multiple sensitivity labels. A CIPSO +host is defined to be the origination or destination system for an IP +datagram. A CIPSO gateway provides IP routing services between two or more +IP networks and may be required to perform label translations between +networks. A CIPSO gateway may be an enhanced CIPSO host or it may just +provide gateway services with no end system CIPSO capabilities. A CIPSO +router is a dedicated IP router that routes IP datagrams between two or more +IP networks. + +An implementation of CIPSO on a host MUST have the capability to reject a +datagram for reasons that the information contained can not be adequately +protected by the receiving host or if acceptance may result in violation of +the host or network security policy. In addition, a CIPSO gateway or router +MUST be able to reject datagrams going to networks that can not provide +adequate protection or may violate the network's security policy. To +provide this capability the following minimal set of configuration +parameters are required for CIPSO implementations: + +HOST_LABEL_MAX - This parameter contains the maximum sensitivity label that +a CIPSO host is authorized to handle. All datagrams that have a label +greater than this maximum MUST be rejected by the CIPSO host. This +parameter does not apply to CIPSO gateways or routers. This parameter need +not be defined explicitly as it can be implicitly derived from the +PORT_LABEL_MAX parameters for the associated interfaces. + + + +Internet Draft, Expires 15 Jan 93 [PAGE 7] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + + +HOST_LABEL_MIN - This parameter contains the minimum sensitivity label that +a CIPSO host is authorized to handle. All datagrams that have a label less +than this minimum MUST be rejected by the CIPSO host. This parameter does +not apply to CIPSO gateways or routers. This parameter need not be defined +explicitly as it can be implicitly derived from the PORT_LABEL_MIN +parameters for the associated interfaces. + +PORT_LABEL_MAX - This parameter contains the maximum sensitivity label for +all datagrams that may exit a particular network interface port. All +outgoing datagrams that have a label greater than this maximum MUST be +rejected by the CIPSO system. The label within this parameter MUST be +less than or equal to the label within the HOST_LABEL_MAX parameter. This +parameter does not apply to CIPSO hosts that support only one network port. + +PORT_LABEL_MIN - This parameter contains the minimum sensitivity label for +all datagrams that may exit a particular network interface port. All +outgoing datagrams that have a label less than this minimum MUST be +rejected by the CIPSO system. The label within this parameter MUST be +greater than or equal to the label within the HOST_LABEL_MIN parameter. +This parameter does not apply to CIPSO hosts that support only one network +port. + +PORT_DOI - This parameter is used to assign a DOI identifier value to a +particular network interface port. All CIPSO labels within datagrams +going out this port MUST use the specified DOI identifier. All CIPSO +hosts and gateways MUST support either this parameter, the NET_DOI +parameter, or the HOST_DOI parameter. + +NET_DOI - This parameter is used to assign a DOI identifier value to a +particular IP network address. All CIPSO labels within datagrams destined +for the particular IP network MUST use the specified DOI identifier. All +CIPSO hosts and gateways MUST support either this parameter, the PORT_DOI +parameter, or the HOST_DOI parameter. + +HOST_DOI - This parameter is used to assign a DOI identifier value to a +particular IP host address. All CIPSO labels within datagrams destined for +the particular IP host will use the specified DOI identifier. All CIPSO +hosts and gateways MUST support either this parameter, the PORT_DOI +parameter, or the NET_DOI parameter. + +This list represents the minimal set of configuration parameters required +to be compliant. Implementors are encouraged to add to this list to +provide enhanced functionality and control. For example, many security +policies may require both incoming and outgoing datagrams be checked against +the port and host label ranges. + + +4.1 Port Range Parameters + +The labels represented by the PORT_LABEL_MAX and PORT_LABEL_MIN parameters +MAY be in CIPSO or local format. Some CIPSO systems, such as routers, may +want to have the range parameters expressed in CIPSO format so that incoming +labels do not have to be converted to a local format before being compared +against the range. If multiple DOIs are supported by one of these CIPSO + + + +Internet Draft, Expires 15 Jan 93 [PAGE 8] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + +systems then multiple port range parameters would be needed, one set for +each DOI supported on a particular port. + +The port range will usually represent the total set of labels that may +exist on the logical network accessed through the corresponding network +interface. It may, however, represent a subset of these labels that are +allowed to enter the CIPSO system. + + +4.2 Single Label CIPSO Hosts + +CIPSO implementations that support only one label are not required to +support the parameters described above. These limited implementations are +only required to support a NET_LABEL parameter. This parameter contains +the CIPSO label that may be inserted in datagrams that exit the host. In +addition, the host MUST reject any incoming datagram that has a label which +is not equivalent to the NET_LABEL parameter. + + +5. Handling Procedures + +This section describes the processing requirements for incoming and +outgoing IP datagrams. Just providing the correct CIPSO label format +is not enough. Assumptions will be made by one system on how a +receiving system will handle the CIPSO label. Wrong assumptions may +lead to non-interoperability or even a security incident. The +requirements described below represent the minimal set needed for +interoperability and that provide users some level of confidence. +Many other requirements could be added to increase user confidence, +however at the risk of restricting creativity and limiting vendor +participation. + + +5.1 Input Procedures + +All datagrams received through a network port MUST have a security label +associated with them, either contained in the datagram or assigned to the +receiving port. Without this label the host, gateway, or router will not +have the information it needs to make security decisions. This security +label will be obtained from the CIPSO if the option is present in the +datagram. See section 4.1.2 for handling procedures for unlabeled +datagrams. This label will be compared against the PORT (if appropriate) +and HOST configuration parameters defined in section 3. + +If any field within the CIPSO option, such as the DOI identifier, is not +recognized the IP datagram is discarded and an ICMP "parameter problem" +(type 12) is generated and returned. The ICMP code field is set to "bad +parameter" (code 0) and the pointer is set to the start of the CIPSO field +that is unrecognized. + +If the contents of the CIPSO are valid but the security label is +outside of the configured host or port label range, the datagram is +discarded and an ICMP "destination unreachable" (type 3) is generated +and returned. The code field of the ICMP is set to "communication with +destination network administratively prohibited" (code 9) or to + + + +Internet Draft, Expires 15 Jan 93 [PAGE 9] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + +"communication with destination host administratively prohibited" +(code 10). The value of the code field used is dependent upon whether +the originator of the ICMP message is acting as a CIPSO host or a CIPSO +gateway. The recipient of the ICMP message MUST be able to handle either +value. The same procedure is performed if a CIPSO can not be added to an +IP packet because it is too large to fit in the IP options area. + +If the error is triggered by receipt of an ICMP message, the message +is discarded and no response is permitted (consistent with general ICMP +processing rules). + + +5.1.1 Unrecognized tag types + +The default condition for any CIPSO implementation is that an +unrecognized tag type MUST be treated as a "parameter problem" and +handled as described in section 4.1. A CIPSO implementation MAY allow +the system administrator to identify tag types that may safely be +ignored. This capability is an allowable enhancement, not a +requirement. + + +5.1.2 Unlabeled Packets + +A network port may be configured to not require a CIPSO label for all +incoming datagrams. For this configuration a CIPSO label must be +assigned to that network port and associated with all unlabeled IP +datagrams. This capability might be used for single level networks or +networks that have CIPSO and non-CIPSO hosts and the non-CIPSO hosts +all operate at the same label. + +If a CIPSO option is required and none is found, the datagram is +discarded and an ICMP "parameter problem" (type 12) is generated and +returned to the originator of the datagram. The code field of the ICMP +is set to "option missing" (code 1) and the ICMP pointer is set to 134 +(the value of the option type for the missing CIPSO option). + + +5.2 Output Procedures + +A CIPSO option MUST appear only once in a datagram. Only one tag type +from the MAC Sensitivity class MAY be included in a CIPSO option. Given +the current set of defined tag types, this means that CIPSO labels at +first will contain only one tag. + +All datagrams leaving a CIPSO system MUST meet the following condition: + + PORT_LABEL_MIN <= CIPSO label <= PORT_LABEL_MAX + +If this condition is not satisfied the datagram MUST be discarded. +If the CIPSO system only supports one port, the HOST_LABEL_MIN and the +HOST_LABEL_MAX parameters MAY be substituted for the PORT parameters in +the above condition. + +The DOI identifier to be used for all outgoing datagrams is configured by + + + +Internet Draft, Expires 15 Jan 93 [PAGE 10] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + +the administrator. If port level DOI identifier assignment is used, then +the PORT_DOI configuration parameter MUST contain the DOI identifier to +use. If network level DOI assignment is used, then the NET_DOI parameter +MUST contain the DOI identifier to use. And if host level DOI assignment +is employed, then the HOST_DOI parameter MUST contain the DOI identifier +to use. A CIPSO implementation need only support one level of DOI +assignment. + + +5.3 DOI Processing Requirements + +A CIPSO implementation MUST support at least one DOI and SHOULD support +multiple DOIs. System and network administrators are cautioned to +ensure that at least one DOI is common within an IP network to allow for +broadcasting of IP datagrams. + +CIPSO gateways MUST be capable of translating a CIPSO option from one +DOI to another when forwarding datagrams between networks. For +efficiency purposes this capability is only a desired feature for CIPSO +routers. + + +5.4 Label of ICMP Messages + +The CIPSO label to be used on all outgoing ICMP messages MUST be equivalent +to the label of the datagram that caused the ICMP message. If the ICMP was +generated due to a problem associated with the original CIPSO label then the +following responses are allowed: + + a. Use the CIPSO label of the original IP datagram + b. Drop the original datagram with no return message generated + +In most cases these options will have the same effect. If you can not +interpret the label or if it is outside the label range of your host or +interface then an ICMP message with the same label will probably not be +able to exit the system. + + +6. Assignment of DOI Identifier Numbers = + +Requests for assignment of a DOI identifier number should be addressed to +the Internet Assigned Numbers Authority (IANA). + + +7. Acknowledgements + +Much of the material in this RFC is based on (and copied from) work +done by Gary Winiger of Sun Microsystems and published as Commercial +IP Security Option at the INTEROP 89, Commercial IPSO Workshop. + + +8. Author's Address + +To submit mail for distribution to members of the IETF CIPSO Working +Group, send mail to: cipso@wdl1.wdl.loral.com. + + + +Internet Draft, Expires 15 Jan 93 [PAGE 11] + + + +CIPSO INTERNET DRAFT 16 July, 1992 + + + + +To be added to or deleted from this distribution, send mail to: +cipso-request@wdl1.wdl.loral.com. + + +9. References + +RFC 1038, "Draft Revised IP Security Option", M. St. Johns, IETF, January +1988. + +RFC 1108, "U.S. Department of Defense Security Options +for the Internet Protocol", Stephen Kent, IAB, 1 March, 1991. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Internet Draft, Expires 15 Jan 93 [PAGE 12] + + + |