Add support for wireguard

[mattiaswal]

Proposal for model:

submodule infix-if-wireguard {
  yang-version 1.1;
  belongs-to infix-interfaces {
    prefix infix-if;
  }

  import ietf-interfaces {
    prefix if;
  }
  import ietf-inet-types {
    prefix inet;
  }
  import infix-crypto-types {
    prefix ixct;
  }
  import ietf-keystore {
    prefix ks;
  }
  import infix-if-type {
    prefix infixift;
  }

  organization "KernelKit";
  contact      "[email protected]";
  description  "Wireguard VPN tunnel";

  revision 2025-01-19 {
    description "Initial revision";
    reference "internal";
  }

  typedef port {
    type inet:port-number;
    description
      "WireGuard UDP port. Valid range: 0..65535.";
  }

  augment "/if:interfaces/if:interface" {
    when "derived-from-or-self(if:type, 'infixift:wireguard')" {
      description "Only shown for if:type infixift:wireguard";
    }
    container wireguard {
      description "WireGuard VPN configuration";

      uses infix-if:local-remote;

      leaf remote-port {
        type port;
        default 51820;
        description "Remote WireGuard endpoint port";
      }

      leaf local-port {
        type port;
        default 51820;
        description "Local WireGuard endpoint port";
      }

      leaf key-pair {
        type ks:asymmetric-key-ref;
        mandatory true;
        description "Reference to WireGuard asymmetric key pair";
        must "not(deref(.)/../ks:public-key-format) or "
          + "(derived-from-or-self(deref(.)/../ks:public-key-format,  'ixct:ed25519-public-key-format') and"
          + "derived-from-or-self(deref(.)/../ks:private-key-format,  'ixct:ed25519-private-key-format'))" {
          error-message "Keys neeed to be in wireguard format";
        }
      }
      leaf preshared-key {
        type ks:symmetric-key-ref;
        description "Optional preshared key for additional security";
        mandatory false;
        must "derived-from-or-self(deref(.)/../ks:key-format, 'ixct:wireguard-symmetric-key-format')" {
          error-message "WireGuard preshared key must be wireguard-symmetric-key-format";
        }
      }
    }
  }
}

and infix-crypto-types:

module infix-crypto-types {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:infix-crypto-types";
  prefix ixct;

  import ietf-crypto-types {
    prefix ct;
  }

  organization "KernelKit";
  contact      "[email protected]";
  description  "Deviations and augments for ietf-keystore.";

  revision 2025-01-19 {
    description "Initial revision";
    reference "internal";
  }

  identity ed25519-public-key-format {
    base ct:public-key-format;
  }

  identity ed25519-private-key-format {
    base ct:public-key-format;
  }

  identity wireguard-symmetric-key-format {
    base ct:symmetric-key-format;
    description "Indicates a 32-byte raw octet string format specific to
     WireGuard pre-shared keys.";
  }
}