Add --iteration tests for domains with different kinds of authorities

[paul-pearce]

Specifically, we should test that different kinds of authorities, such as non second-level-domains should function.

A challenge here is that our test domain may not easily facilitate this. @zakird?

[dadrian]

I don't quite understand what you mean. What kind of test domain do you want?

[paul-pearce]

For example. I want an A record for dog.cat.example.com, where the authoritative is cat.example.com not example.com. (Clearly example.com is also authoritative, but I want it to not respond with an A but rather delegate to cat.example.com).

This would have caught #117

There are plenty of examples of this, but we need to setup our test domain to do this, and I don't know what the constraints of our hosting are.

[dadrian]

Can you post what the record we'd need to set are? Then myself or @zakird can look into how we would set them.

[paul-pearce]

Here's an example

$ echo "star.c10r.facebook.com" | ./zdns/zdns A --iterative --trace | jq "."
{
  "trace": [
REMOVED
    {
      "cached": false,
      "layer": "facebook.com",
      "depth": 3,
      "name_server": "69.171.239.12:53",
      "name": "star.c10r.facebook.com",
      "class": 1,
      "type": 1,
      "results": {
        "flags": {
          "error_code": 0,
          "response": true,
          "opcode": 0,
          "authoritative": false,
          "truncated": false,
          "recursion_desired": false,
          "recursion_available": false,
          "authenticated": false,
          "checking_disabled": false
        },
        "protocol": "udp",
        "authorities": [
          {
            "answer": "a.ns.c10r.facebook.com",
            "name": "c10r.facebook.com",
            "class": "IN",
            "type": "NS",
            "ttl": 3600
          },
          {
            "answer": "b.ns.c10r.facebook.com",
            "name": "c10r.facebook.com",
            "class": "IN",
            "type": "NS",
            "ttl": 3600
          }
        ],
        "additionals": [
          {
            "answer": "2a03:2880:fffe:b:face:b00c:0:99",
            "name": "a.ns.c10r.facebook.com",
            "class": "IN",
            "type": "AAAA",
            "ttl": 3600
          },
          {
            "answer": "69.171.239.11",
            "name": "a.ns.c10r.facebook.com",
            "class": "IN",
            "type": "A",
            "ttl": 3600
          },
          {
            "answer": "2a03:2880:ffff:b:face:b00c:0:99",
            "name": "b.ns.c10r.facebook.com",
            "class": "IN",
            "type": "AAAA",
            "ttl": 3600
          },
          {
            "answer": "69.171.255.11",
            "name": "b.ns.c10r.facebook.com",
            "class": "IN",
            "type": "A",
            "ttl": 3600
          }
        ],
        "answers": []
      }
    },
    {
      "cached": false,
      "layer": "c10r.facebook.com",
      "depth": 4,
      "name_server": "69.171.239.11:53",
      "name": "star.c10r.facebook.com",
      "class": 1,
      "type": 1,
      "results": {
        "flags": {
          "error_code": 0,
          "response": true,
          "opcode": 0,
          "authoritative": true,
          "truncated": false,
          "recursion_desired": false,
          "recursion_available": false,
          "authenticated": false,
          "checking_disabled": false
        },
        "protocol": "udp",
        "authorities": [
          {
            "answer": "a.ns.c10r.facebook.com",
            "name": "c10r.facebook.com",
            "class": "IN",
            "type": "NS",
            "ttl": 3600
          },
          {
            "answer": "b.ns.c10r.facebook.com",
            "name": "c10r.facebook.com",
            "class": "IN",
            "type": "NS",
            "ttl": 3600
          }
        ],
        "additionals": [
          {
            "answer": "2a03:2880:fffe:b:face:b00c:0:99",
            "name": "a.ns.c10r.facebook.com",
            "class": "IN",
            "type": "AAAA",
            "ttl": 3600
          },
          {
            "answer": "69.171.239.11",
            "name": "a.ns.c10r.facebook.com",
            "class": "IN",
            "type": "A",
            "ttl": 3600
          },
          {
            "answer": "2a03:2880:ffff:b:face:b00c:0:99",
            "name": "b.ns.c10r.facebook.com",
            "class": "IN",
            "type": "AAAA",
            "ttl": 3600
          },
          {
            "answer": "69.171.255.11",
            "name": "b.ns.c10r.facebook.com",
            "class": "IN",
            "type": "A",
            "ttl": 3600
          }
        ],
        "answers": [
          {
            "answer": "157.240.17.14",
            "name": "star.c10r.facebook.com",
            "class": "IN",
            "type": "A",
            "ttl": 60
          }
        ]
      }
    }
  ],
  "data": {
    "flags": {
      "error_code": 0,
      "response": true,
      "opcode": 0,
      "authoritative": true,
      "truncated": false,
      "recursion_desired": false,
      "recursion_available": false,
      "authenticated": false,
      "checking_disabled": false
    },
    "protocol": "udp",
    "authorities": [],
    "additionals": [],
    "answers": [
      {
        "answer": "157.240.17.14",
        "name": "star.c10r.facebook.com",
        "class": "IN",
        "type": "A",
        "ttl": 60
      }
    ]
  },
  "timestamp": "2017-09-01T10:56:48-07:00",
  "status": "NOERROR",
  "class": "IN",
  "name": "star.c10r.facebook.com"
}

[phillip-stephens]

If I'm understanding the ask correctly, I think I added this in #374. More details available in that PR, but there's unique nameservers for zdns-testing.com, subdomain0.zdns-testing.com and subdomain1.subdomain0.zdns-testing.com and I test if iterative resolution works in this controlled context.

What I think I'll add is if we run with --result-verbosity trace, I should be able to validate that at each level of the iteration, we asked the correct name server. So for resolving a.subdomain1.subdomain0.zdns-testing.com, we should first try the nameservers for zdns-testing.com, then the next layer, then get our final answer.

[zakird]

I don't think that #374 really tests complex iterative cases, the test is a pretty trivial best-case-scenario, but with a large number of names. Overall, we don't really have any tests that actually make sure the logic in our iterative resolver is particularly resiliant. That said, this issue is pretty poorly defined and since nobody seems to know what it's aiming for, I think it's fair to close it and focus on more concrete issues.