% JSON Domain Format as Implemented by Pdns-Pipe-Nmc
+This document is based on
+[Namecoin Domain Name Specification](https://wiki.namecoin.info/index.php?title=Domain_Name_Specification).
+It tries to follow it closely, and clarify parts that are not
+specified, or specified ambiguously, in the original document.
+
+One notable deviation is the specification of `"delegate"` and `"import"`
+attributes: domain objects to which their value point are
+replacing/merging to the domain object in which they are defined.
+This seems to be in line with at least one existing "real world"
+implementation.
+
+This specification is implemented by the `pdns-pipe-nmc` program.
+
## Data Format
### `DomObj` Object
* Any attribute specified as `Array(String)` may be present in the
JSON document as a plain `String`, which is interpreted the same way
- as an `Array` containing a single `String` element.
+ as an `Array` containing a single `String` element. In other words,
+ `"ip":"1.2.3.4"` is equivalent to `"ip":["1.2.3.4"]`. (This does not
+ apply to non-string-array attributes, like "service" or "ds".)
* If `DomObj` is a `String`, it is interpreted as an IPv4 address.
In other words, string `"1.2.3.4"` is the same as the Map
`"{\"ip\":\"1.2.3.4\"}"`. Such "shorthand" DomObj can be present at
| 2 | Int | Priority |
| 3 | Int | Weight |
| 4 | Int | Port |
-| 5 | String | Hostname |
+| 5 | String | FQDN |
#### Notes
* `Service` and `Protocol` are two elements of the domain name, without
the undescore '_'.
* `SrvObj` with Service `"smtp"`, Protocol `"tcp"` and Port `25` is also
- interpteted as an `MX` DNS resource.
+ interpteted as an `MX` DNS resource at the domain level containing the
+ `"service"` object.
* When lookup is performed for `SRV` records at fqdn
`"_serv._proto.sub.dom.bit"`, domain object for `"sub.dom.bit"` must be
fetched, and in this object, `SrvObj`s for the Service `"serv"` and
| 1 | String | Match value - certificate or hash of it as hex string |
| 2 | Int | Include subdomains - 0:No, 1:Yes |
+#### Notes
+
+* The fields of the object correspond to the attributes defined by
+ [RFC-6698](http://tools.ietf.org/html/rfc6698) ("DANE").
+
### `DsObj` Object
`DsObj` is a heterogenous Array of fixed size containing 4 elements:
| 2 | Int | Hash Type |
| 3 | String | Hash Value as hex string |
+#### Notes
+
+* The fields of the object correspond to the attributes defined by
+ [RFC-3658](http://tools.ietf.org/html/rfc3658).
+
## Data Interpretation
### Semantics of the Attributes
corresponding to the FQDN "sub.dom.bit" with the value
```
-"service": [ ["imap", "tcp", 0, 0, 143, "mail.host.com." ],
- ["smtp", "tcp", 0, 0, 25, "relay.host.com."] ]
+"service": [ ["imap", "tcp", 0, 0, 143, "mail.host.com" ],
+ ["smtp", "tcp", 0, 0, 25, "relay.host.com"] ]
```
corresponds to two `SRV` RRs at two different points in the
sub.dom.bit. IN MX 0 relay.host.com.
```
+Note: Hostname element **must** be specified as fully qualified domain
+name of the host, and **must not** terminate with a dot.
+This requirement seems to be in line with many existing definitions in
+the blockchain; however it deviates from the BIND zone file format, in
+which names that have not terminating dot are automatically expanded
+by attaching the current origin zone to the end of the name.
+
#### ip attribute
Contains a list of strings representing IPv4 addresses in dotted
#### ip6 attribute
+Contains a list of strings representing IPv6 addresses in semicolon
+quads notation. For example,
+
+```
+"ip6": ["2001:4860:0:1001::68"]
+```
+
+translates into one AAAA RR:
+
+```
+ IN AAAA 2001:4860:0:1001::68
+```
#### tor attribute
+Does not translate into any DNS RR. Contains Tor hidden service address.
#### i2p attribute
+Does not translate into any DNS RR. Contains an object with three
+optional String attributes: `"destination"`, `"name"` and `"b32"`.
#### freenet attribute
+Does not translate into any DNS RR. Contains Freesite key.
#### alias attribute
+Translates into `CNAME` RR. Invalidates all other attributes except
+the element of the `"map"` with empty key. Such element is analysed
+and its contents merged into the base domain before the check.
+
+Note: Hostname element **must** be specified as fully qualified domain
+name of the host, and **must not** terminate with a dot.
#### translate attribute
+Translates into `DNAME` RR. Invalidates the contents of the `"map"`
+attribute, except the element of the `"map"` with empty key. Such
+element is analysed and its contents merged into the base domain
+before the check.
#### email attribute
+Translates into the `email` element of the SOA and RP RRs. The
+value `"email":"user@domain.tld"` becomes `user.domain.tld.`
+in the DNS record.
#### loc attribute
+Translates into `LOC` RR. Value must conform to the format defined
+by [RFC-1876](http://tools.ietf.org/html/rfc1876).
#### info attribute
+Does not translate into any DNS RR. Contains a JSON object with
+format unspecified at the time of this writing.
#### ns attribute
+Translates into `NS` RR. Invalidates all other attributes, except
+the element of the `"map"` with empty key. Such element is analysed
+and its contents merged into the base domain before the check.
+
+Note: the value of the attribute **must** be specified as fully
+qualified domain name of the host, and **must not** terminate
+with a dot.
#### delegate attribute
+Does not translate into any DNS RR. Instead, the value is used as
+a key for namecoin lookup (i.e. the value must be specified with
+the namespace prefix), and the result of the lookup replaces all
+other attributes, except the element of the `"map"` with empty key.
+Such element is analysed and its contents merged into the base
+domain before the check.
#### import attribute
+Does not translate into any DNS RR. Instead, the value is used as
+a key for namecoin lookup (i.e. the value must be specified with
+the namespace prefix), and the result of the lookup is merged with
+the current domain object.
#### map attribute
+JSON Map object containing subdomain names as its keys and domain
+objects as values. Element of the map with empty key "" has special
+meaning: the value of this map element is merged into the current
+domain object. This operaton happens first when a new domain object
+is analyzed, and is performed recursively. In the result of the
+merge, the `"map"` does not contain the element with empty key.
+Further operatons that can potentially modify the contents of the
+current domain object (`import` and `delegate` lookups) start when
+the empty element of the `"map"` has been recursively merged into
+the current object.
#### fingerprint attribute
+Does not translate into any DNS RR. Contains a list of TLS
+certificate fingerprints. Deprecated.
#### tls attribute
+Intended to carry attributes as per
+[RFC-6698](http://tools.ietf.org/html/rfc6698) ("DANE").
+As of this writing, the specification is under discussion.
#### ds attribute
+Translates into `DS` RR. Carries attributes defined by
+[RFC-4034](http://tools.ietf.org/html/rfc4034).
### Lookup Sequence
1. Value of the element of the `"map"` attribute with the key `""`
(empty string) is recursively merged into the base domain. The
`""` element of the `"map"` is removed from the result.
-2. If attribute `"import"` does not exist in the resulting object,
- recursion stops, and step 3 is performed on the result
+2. If attribute `"delegate"` does not exist in the resulting object,
+ step 3 is is performed. If attribute `"delegate"` exists, in
+ the resulting object, lookup is performed for the values of this
+ attribute, and fetched object replaces the base domain completely.
+ The result is passed as base domain to step 1.
+3. If attribute `"import"` does not exist in the resulting object,
+ recursion stops, and step 4 is performed on the result
If attribute `"import"` exists in the resulting object, lookup is
- is performed for the values of this attribute, and fetched objects
- are recursively merged into the base domain. The `"import"` attribute
- is removed from the result. Then the result is passed as base
- domain to step 1.
-3. If subdomain chain is empty, recursion stops, and step 4 is
+ performed for the values of this attribute, and fetched objects
+ are recursively merged into the base domain. The `"import"`
+ attribute is removed from the result. Then the result is passed
+ as base domain to step 1.
+4. If subdomain chain is empty, recursion stops, and step 5 is
performed on the result. If subdomain chain is not empty, next
element is taken out of the chain, and the `"map"` is looked
up for the element with the name matching the subdomain element.
The value of this element of the `"map"` is passed as base domain
to step 1. If matching element does not exist, lookup is considered
failed.
-4. Domain object with all `""` map elements and all `"import"` data
- merged is "normalized" by removal of attributes that are nullified
- by the presence of other attributes.
+5. Domain object in which all `""` map elements and all `"delegate"`
+ and `"import"` elements are acted upon and removed, is then
+ "normalized" by removal of attributes that are nullified by the
+ presence of other attributes.
Note that the process involves recursion nested to three levels.
### Merging Procedure
-When a domain object `sub` needs merging into a domain object `base`,
+When a domain object `extra` needs merging into a domain object `base`,
the following rules are applied:
* Of `String` and other "scalar" attributes, one is chosen, the value
* On `Array` attribtes, `union` operation is performed. (Of equal
elements, only one copy is left.)
* On `Map` attributes, recursive merge is performed. On the top level,
- elemens with keys that are only present in either `base` or `sub`
+ elemens with keys that are only present in either `base` or `extra`
object are all put into result. The values of the elements that are
- present in both `base` and `sub` are merged according to the rules
- applicable to their type.
+ present in both `base` and `extra` objects are merged according to
+ the rules applicable to their type.
projects / pdns-pipe-nmc.git / blobdiff