[email protected]

module ietf-if-flexible-encapsulation {
  yang-version 1.1;
  namespace
    "urn:ietf:params:xml:ns:yang:ietf-if-flexible-encapsulation";
  prefix if-flex;

  import ietf-interfaces {
    prefix if;
    reference
      "RFC 8343: A YANG Data Model For Interface Management";
  }

  import iana-if-type {
    prefix ianaift;
    reference
      "RFC 7224: IANA Interface Type YANG Module";
  }

  import ieee802-dot1q-types {
    prefix dot1q-types;
    revision-date 2022-01-19;
    reference
      "IEEE Std 802.1Q-2022: IEEE Standard for Local and
       metropolitan area networks -- Bridges and Bridged Networks";
  }

  import ietf-if-extensions {
    prefix if-ext;
    reference
      "RFC XXXX: Common Interface Extension YANG Data Models";
  }

  organization
    "IETF NETMOD (NETCONF Data Modeling Language) Working Group";

  contact
    "WG Web:   <http://tools.ietf.org/wg/netmod/>
     WG List:  <mailto:netmod@ietf.org>

     Editor:   Robert Wilton
               <mailto:rwilton@cisco.com>";

  description
    "This YANG module describes interface configuration for flexible
     classification and rewrites of IEEE 802.1Q VLAN tagged Ethernet
     traffic.

     Copyright (c) 2022 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject to
     the license terms contained in, the Revised BSD License set
     forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX
     (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
     for full legal notices.

     The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
     NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
     'MAY', and 'OPTIONAL' in this document are to be interpreted as
     described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
     they appear in all capitals, as shown here.";

  revision 2023-01-26 {
    description
      "Latest draft revision";
    reference
      "RFC XXXX: Sub-interface VLAN YANG Data Models";
  }

  feature flexible-rewrites {
    description
      "This feature indicates that the network element supports
        specifying flexible rewrite operations.";
  }

  feature asymmetric-rewrites {
    description
      "This feature indicates that the network element supports
       specifying different rewrite operations for the ingress
       rewrite operation and egress rewrite operation.";
  }

  feature dot1q-tag-rewrites {
    description
      "This feature indicates that the network element supports the
       flexible rewrite functionality specifying 802.1Q tag
       rewrites.";
  }

  grouping flexible-match {
    description
      "Represents a flexible frame classification:

       The rules for a flexible match are:
         1. Match-type: default, untagged, priority tag, or tag
            stack.
         2. Each tag in the stack of tags matches:
          a. tag type (802.1Q or 802.1ad) +
          b. tag value:
            i.   single tag
            ii.  set of tag ranges/values.
            iii. 'any' keyword";

    choice match-type {
      mandatory true;

      description
        "Provides a choice of how the frames may be
         matched";

      case default {
        description
          "Default match";

        leaf default {
          type empty;

          description
            "Default match.  Matches all traffic not matched to any
             other peer sub-interface by a more specific
             encapsulation.";
        }
      }

      case untagged {
        description
          "Match untagged Ethernet frames only";
        leaf untagged {
          type empty;

          description
            "Untagged match.  Matches all untagged traffic.";
        }
      }

      case dot1q-priority-tagged {
        description
          "Match 802.1Q priority tagged Ethernet frames only";

        container dot1q-priority-tagged {
          description
            "802.1Q priority tag match";

          leaf tag-type {
            type dot1q-types:dot1q-tag-type;
            mandatory true;

            description
              "The 802.1Q tag type of matched priority
               tagged packets";
          }
        }
      }

      case dot1q-vlan-tagged {
        container dot1q-vlan-tagged {
          description
            "Matches VLAN tagged frames";

          container outer-tag {
            must 'tag-type = "dot1q-types:s-vlan" or '
               + 'tag-type = "dot1q-types:c-vlan"' {

              error-message
                "Only C-VLAN and S-VLAN tags can be matched.";

              description
                "For IEEE 802.1Q interoperability, only C-VLAN and
                 S-VLAN tags can be matched.";
            }

            description
              "Classifies traffic using the outermost (first) VLAN
               tag on the frame.";

            uses "dot1q-types:"
               + "dot1q-tag-ranges-or-any-classifier-grouping";
          }

          container second-tag {
            must
              '../outer-tag/tag-type = "dot1q-types:s-vlan" and '
            + 'tag-type = "dot1q-types:c-vlan"' {

              error-message
                "When matching two tags, the outermost (first) tag
                 must be specified and of S-VLAN type and the second
                 outermost tag must be of C-VLAN tag type.";

              description
                "For IEEE 802.1Q interoperability, when matching two
                 tags, it is required that the outermost (first) tag
                 exists and is an S-VLAN, and the second outermost
                 tag is a C-VLAN.";
            }

            presence "Also classify on the second VLAN tag.";

            description
              "Classifies traffic using the second outermost VLAN tag
               on the frame.";

            uses "dot1q-types:"
               + "dot1q-tag-ranges-or-any-classifier-grouping";
          }

          leaf match-exact-tags {
            type empty;
            description
              "If set, indicates that all 802.1Q VLAN tags in the
               Ethernet frame header must be explicitly matched, i.e.
               the EtherType following the matched tags must not be a
               802.1Q tag EtherType.  If unset then extra 802.1Q VLAN
               tags are allowed.";
          }
        }
      }
    }
  }

  grouping dot1q-tag-rewrite {
    description
      "Flexible rewrite grouping.  Can be either be expressed
       symmetrically, or independently in the ingress and/or egress
       directions.";

    leaf pop-tags {
      type uint8 {
        range "1..2";
      }

      description
        "The number of 802.1Q VLAN tags to pop, or translate if used
         in conjunction with push-tags.

         Popped tags are the outermost tags on the frame.";
    }

    container push-tags {
      presence "802.1Q tags are pushed or translated";

      description
        "The 802.1Q tags to push on the front of the frame, or
         translate if configured in conjunction with pop-tags.";

      container outer-tag {
        must 'tag-type = "dot1q-types:s-vlan" or '
           + 'tag-type = "dot1q-types:c-vlan"' {

          error-message "Only C-VLAN and S-VLAN tags can be pushed.";

          description
            "For IEEE 802.1Q interoperability, only C-VLAN and S-VLAN
             tags can be pushed.";
        }

        description
          "The outermost (first) VLAN tag to push onto the frame.";

        uses dot1q-types:dot1q-tag-classifier-grouping;
      }

      container second-tag {
        must '../outer-tag/tag-type = "dot1q-types:s-vlan" and '
           + 'tag-type = "dot1q-types:c-vlan"' {

          error-message
            "When pushing/rewriting two tags, the outermost tag must
             be specified and of S-VLAN type and the second outermost
             tag must be of C-VLAN tag type.";

          description
            "For IEEE 802.1Q interoperability, when pushing two tags,
             it is required that the outermost tag exists and is an
             S-VLAN, and the second outermost tag is a C-VLAN.";
        }

        presence
          "In addition to the first tag, also push/rewrite a second
           VLAN tag.";

        description
          "The second outermost VLAN tag to push onto the frame.";

        uses dot1q-types:dot1q-tag-classifier-grouping;
      }
    }
  }

  grouping flexible-rewrite {
    description
      "Grouping for flexible rewrites of fields in the L2 header.

       Restricted to flexible 802.1Q VLAN tag rewrites, but could be
       extended to cover rewrites of other fields in the L2 header in
       future.";

    container dot1q-tag-rewrite {
      if-feature "dot1q-tag-rewrites";

      description
        "802.1Q VLAN tag rewrite.

         Translate operations are expressed as a combination of tag
         push and pop operations.  E.g., translating the outer tag is
         expressed as popping a single tag, and pushing a single tag.
         802.1Q tags that are translated SHOULD preserve the PCP and
         DEI fields unless if a different QoS behavior has been
         specified.";
      uses dot1q-tag-rewrite;
    }
  }

  augment "/if:interfaces/if:interface/if-ext:encapsulation/"
        + "if-ext:encaps-type" {
    when "derived-from-or-self(../if:type,
                               'ianaift:ethernetCsmacd') or
          derived-from-or-self(../if:type,
                               'ianaift:ieee8023adLag') or
          derived-from-or-self(../if:type, 'ianaift:l2vlan') or
          derived-from-or-self(../if:type,
                               'if-ext:ethSubInterface')" {

        description
          "Applies only to Ethernet-like interfaces and
           sub-interfaces.";
    }

    description
      "Augment the generic interface encapsulation with flexible
       match and rewrite for VLAN sub-interfaces.";

    case flexible {
      description
        "Flexible encapsulation and rewrite";

      container flexible {
        description
          "Flexible encapsulation allows for the matching of ranges
           and sets of 802.1Q VLAN Tags and performing rewrite
           operations on the VLAN tags.

           The structure is also designed to be extended to allow for
           matching/rewriting other fields within the L2 frame header
           if required.";

        container match {
          description
            "Flexibly classifies Ethernet frames to a sub-interface
             (or interface) based on the L2 header fields.

             Only frames matching the classification configured on a
             sub-interface/interface are processed on that
             sub-interface/interface.

             Frames that do not match any sub-interface are processed
             directly on the parent interface, if it is associated
             with a forwarding instance, otherwise they are dropped.

             If a frame could be classified to multiple
             sub-interfaces then they get classified to the
             sub-interface with the most specific match.  E.g.,
             matching two VLAN tags in the frame is more specific
             than matching the outermost VLAN tag, which is more
             specific than the catch all 'default' match.";

          uses flexible-match;
        }

        container rewrite {
          if-feature "flexible-rewrites";

          description
            "L2 frame rewrite operations.

             Rewrites allows for modifications to the L2 frame header
             as it transits the interface/sub-interface.  Examples
             include adding a VLAN tag, removing a VLAN tag, or
             rewriting the VLAN Id carried in a VLAN tag.";

          choice direction {
            description
              "Whether the rewrite policy is symmetrical or
               asymmetrical.";

            case symmetrical {
              container symmetrical {
                uses flexible-rewrite;

                description
                  "Symmetrical rewrite.  Expressed in the ingress
                   direction, but the reverse operation is applied to
                   egress traffic.

                   E.g., if a tag is pushed on ingress traffic, then
                   the reverse operation is a 'pop 1', that is
                   performed on traffic egressing the interface, so
                   a peer device sees a consistent L2 encapsulation
                   for both ingress and egress traffic.";
              }
            }

            case asymmetrical {
              if-feature "asymmetric-rewrites";

              description
                "Asymmetrical rewrite.

                 Rewrite operations may be specified in only a single
                 direction, or different rewrite operations may be
                 specified in each direction.";

              container ingress {
                uses flexible-rewrite;

                description
                  "A rewrite operation that only applies to ingress
                   traffic.

                   Ingress rewrite operations are performed before
                   the frame is subsequently processed by the
                   forwarding operation.";
              }

              container egress {
                uses flexible-rewrite;

                description
                  "A rewrite operation that only applies to egress
                   traffic.";
              }
            }
          }
        }

        container local-traffic-default-encaps {
          presence "A local traffic default encapsulation has been
                    specified.";

          description
            "Specifies the 802.1Q VLAN tags to use by default for
             locally sourced traffic from the interface.

             Used for encapsulations that match a range of VLANs (or
             'any'), where the source VLAN Ids are otherwise
             ambiguous.";

          container outer-tag {
            must 'tag-type = "dot1q-types:s-vlan" or '
               + 'tag-type = "dot1q-types:c-vlan"' {

              error-message
                "Only C-VLAN and S-VLAN tags can be matched.";

              description
                "For IEEE 802.1Q interoperability, only C-VLAN and
                 S-VLAN tags can be matched.";
            }

            description
              "The outermost (first) VLAN tag for locally sourced
               traffic.";

            uses dot1q-types:dot1q-tag-classifier-grouping;
          }

          container second-tag {
            must
              '../outer-tag/tag-type = "dot1q-types:s-vlan" and '
            + 'tag-type = "dot1q-types:c-vlan"' {

              error-message
                "When specifying two tags, the outermost (first) tag
                 must be specified and of S-VLAN type and the second
                 outermost tag must be of C-VLAN tag type.";

              description
                "For IEEE 802.1Q interoperability, when specifying
                 two tags, it is required that the outermost (first)
                 tag exists and is an S-VLAN, and the second
                 outermost tag is a C-VLAN.";
            }

            presence
              "Indicates existence of a second outermost VLAN tag.";

            description
              "The second outermost VLAN tag for locally sourced
               traffic.";

            uses dot1q-types:dot1q-tag-classifier-grouping;
          }
        }
      }
    }
  }
}