Add DDR experiment spec

data-formats/df-002-dnst.md

@@ -159,13 +159,14 @@ the name because we changed our way of representing getaddrinfo-like resolutions
 
 ```JavaScript
 {
-    // fields currently used as 2022-09-08
+    // fields currently used as 2025-01-31
     "answer_type": "AAAA",
     "asn": 13335
     "as_org_name": "Cloudflare, Inc."
     "hostname": "",
     "ipv4": "1.1.1.1",
     "ipv6": "",
+    "svcb": null,
     "ttl": null,
 
     // specified but unused or deprecated fields
@@ -180,9 +181,9 @@ the name because we changed our way of representing getaddrinfo-like resolutions
 
 - `answer_type`: (`string`) like `Query.query_type`.
 
-- `asn`: (`int`) the Authonomous System Number of the returned ipv4 or ipv6 address.
+- `asn`: (`int`) the Autonomous System Number of the returned ipv4 or ipv6 address.
 
-- `as_org_name`: (`int`) the Authonomous System organisation name of the returned ipv4 or ipv6 address.
+- `as_org_name`: (`string`) the Autonomous System organisation name of the returned ipv4 or ipv6 address.
 
 - `expiration_limit` (`string`; only for SOA answers): the time
 after which this zone should no longer be authoritative.
@@ -211,8 +212,35 @@ that should be elapsed before the zone should be retried in case of failure.
 - `serial_number` (`int`; only for SOA answers): version number
 of the original copy of the zone.
 
+- `svcb`: (only for SCVB answers): the SVCB record, see below.
+
 - `ttl` (`int`; nullable): the TTL if known, otherwise `null`.
 
+### SVCB answer
+
+Answers with the SVCB record contain the `svcb` key that is an object like this:
+
+```Javascript
+{
+    "priority": 1,
+    "target_name": "dns.quad9.net.",
+    "params": {
+        "alpn": "h2",
+        "dohpath": "/dns-query{?dns}",
+        "ipv4hint": "9.9.9.9,149.112.112.112",
+        "ipv6hint": "2620:fe::fe",
+        "port": "443"
+    }
+}
+```
+The svcb object follows the SVCB specifation in RFC9460.
+
+- `priority`: (`string`) The SvcPriority
+
+- `target_name`: (`string`) The TargetName as it appears in the record.
+
+- `params`: The SvcParams, as an object with string values.
+
 ## Example
 
 In the following example we've omitted all the keys that are

nettests/ts-041-ddr.md

@@ -0,0 +1,158 @@
+# Specification version number
+
+2025-01-21-000
+
+* _status_: experimental
+
+# Specification name
+
+ddr
+
+# Test preconditions
+
+* An internet connection
+
+# Expected impact
+
+Query the DDR protocol at the local recursive resolver, thus gathering information about DoE services in designated resolvers available and suggested to the user.
+
+# Expected inputs
+
+This experiment does not require inputs. It will by default query the system-configured recursive resolver. On Linux systems, this is the recursive resolver that is configured in the `/etc/resolve.conf` file.
+
+This experiment can be configured to use a custom resolver. In this case, this resolver will be used. In this case the CustomResolver configuration property must be set to a domain or and IP-address, optionally providing a port. When no port is supplied, the default DNS port of 53 is used.
+
+# Test description
+
+The DDR (Discovery of Designated Resolvers) protocol is used for client to establish the connection to a encrypted DNS resolver. In most cases, DNS queries from the client are not configured with encryption by default, such as when only an IP is supplied by DHCP. With DDR a client can query a DNS recursive resolver for designated resolvers (encrypted resolvers). The recursive resolver will respond with a list of designated resolvers with their supported protocols.
+
+This experiment issues such a DDR query and reports the result. 
+
+# Expected output
+
+## Semantics
+
+The `test_keys` key of the measurement has such a structure:
+
+```JSON
+{
+	"queries": [],
+  "supports_ddr": false,
+  "failure": null
+}
+```
+
+The `supports_ddr` key is set to `true` only when the resolver returned a valid DDR response. It does not provide information about wether the designated resolver are valid.
+
+The key `queries` follows the df-002-dnst format, with `svcb` key filled with the ddr responses.
+
+A svcb record in an answer of the queries object looks like this:
+
+```JSON
+{
+    "priority": 1,
+    "target_name": "one.one.one.one.",
+    "params":{
+        "alpn":"h2,h3",
+        "dohpath":"/dns-query{?dns}",
+        "ipv4hint":"1.1.1.1,1.0.0.1",
+        "ipv6hint":"2606:4700:4700::1111,2606:4700:4700::1001",
+        "port":"443"
+    }
+}
+```
+
+The priority and target_name keys are directly from the SVCB record, where priority specifies the priority among the records at which use this record and target specifies the designated resolver. The key `params` is a map from string to string, that includes the keys that were specified for the SVCB record.
+In the case of this example, the `parmas` map includes this information:
+
+- `alpn`: The protocol this designated resolver uses, so in this case HTTP2 or HTTP3 for DNS over HTTPS
+- `dohpath`: How the URL needs to be constructed to send a DoH query to the designated resolver.
+- `ipv4hint`: How to reach the resolver via IPv4
+- `ipv6hint`: How to reach the resolver via IPv6
+- `port`: The port at which to reach the resolver
+
+## Example output sample
+
+```JSON
+
+{
+  "annotations": {
+    "architecture": "amd64",
+    "engine_name": "ooniprobe-engine",
+    "engine_version": "3.25.0-alpha",
+    "go_version": "go1.22.2",
+    "platform": "linux",
+    "vcs_modified": "true",
+    "vcs_revision": "8ddec182caff7c1f9d49aa76a69d2fd10733e613",
+    "vcs_time": "2024-12-19T14:59:47Z",
+    "vcs_tool": "git"
+  },
+  "data_format_version": "0.2.0",
+  "input": null,
+  "measurement_start_time": "2025-01-31 09:58:28",
+  "probe_asn": "AS3320",
+  "probe_cc": "DE",
+  "probe_ip": "127.0.0.1",
+  "probe_network_name": "Deutsche Telekom AG",
+  "report_id": "20250131T095828Z_ddr_DE_3320_n1_tNwEDtCeE2KK3ZGS",
+  "resolver_asn": "AS42",
+  "resolver_ip": "74.63.24.222",
+  "resolver_network_name": "WoodyNet, Inc.",
+  "software_name": "miniooni",
+  "software_version": "3.25.0-alpha",
+  "test_keys": {
+    "queries": {
+      "answers": [
+        {
+          "answer_type": "SVCB",
+          "ttl": null,
+          "svcb": {
+            "priority": 2,
+            "target_name": "dns.quad9.net.",
+            "params": {
+              "alpn": "h2",
+              "dohpath": "/dns-query{?dns}",
+              "ipv4hint": "9.9.9.9,149.112.112.112",
+              "ipv6hint": "2620:fe::fe",
+              "port": "443"
+            }
+          }
+        },
+        {
+          "answer_type": "SVCB",
+          "ttl": null,
+          "svcb": {
+            "priority": 2,
+            "target_name": "dns.quad9.net.",
+            "params": {
+              "alpn": "h2",
+              "dohpath": "/dns-query{?dns}",
+              "ipv4hint": "9.9.9.9,149.112.112.112",
+              "ipv6hint": "2620:fe::fe",
+              "port": "443"
+            }
+          }
+        }
+      ],
+      "engine": "udp",
+      "failure": null,
+      "hostname": "_dns.resolver.arpa.",
+      "query_type": "SVCB",
+      "raw_response": "xnuBAAABAAIAAAAEBF9kbnMIcmVzb2x2ZXIEYXJwYQAAQAABwAwAQAABAAAAPAA/AAEDZG5zBXF1YWQ5A25ldAAAAQAEA2RvdAADAAIDVQAEAAgJCQkJlXBwcAAGABAmIAD+AAAAAAAAAAAAAAD+wAwAQAABAAAAPABSAAIDZG5zBXF1YWQ5A25ldAAAAQADAmgyAAMAAgG7AAQACAkJCQmVcHBwAAYAECYgAP4AAAAAAAAAAAAAAP4ABwAQL2Rucy1xdWVyeXs/ZG5zfQNkbnMFcXVhZDkDbmV0AAABAAEAAAA8AAQJCQkJwM0AAQABAAAAPAAElXBwcMDNABwAAQAAADwAECYgAP4AAAAAAAAAAAAAAP4AACkE0AAAgAAAAA==",
+      "resolver_hostname": null,
+      "resolver_port": null,
+      "resolver_address": "192.168.10.1:53",
+      "t0": 0.000070584,
+      "t": 0.013585498,
+      "tags": null
+    },
+    "supports_ddr": true,
+    "failure": null
+  },
+  "test_name": "ddr",
+  "test_runtime": 0.013683332,
+  "test_start_time": "2025-01-31 09:58:28",
+  "test_version": "0.1.0"
+}
+
+```