This implements parts of RFC 7871 where Consul is acting as an authoritative name server (or forwarding resolver when recursors are configured)
If ECS opt is present in the request we will mirror it back and return a response with a scope of 0 (global) or with the same prefix length as the request (indicating its valid specifically for that subnet).
We only mirror the prefix-length (non-global) for prepared queries as those could potentially use nearness checks that could be affected by the subnet. In the future we could get more sophisticated with determining the scope bits and allow for better caching of prepared queries that don’t rely on nearness checks.
The other thing this does not do is implement the part of the ECS RFC related to originating ECS headers when acting as a intermediate DNS server (forwarding resolver). That would take a quite a bit more effort and in general provide very little value. Consul will currently forward the ECS headers between recursors and the clients transparently, we just don't originate them for non-ECS clients to get potentially more accurate "location aware" results.
- Improve resilience of testrpc.WaitForLeader()
- Add additionall retry to CI
- Increase "go test" timeout to 8m
- Add wait for cluster leader to several tests in the agent package
- Add retry to some tests in the api and command packages
* Fixes the DNS recursor properly resolving the requests
* Added a test case for the recursor bug
* Refactored code && added a test case for all failing recursors
* Inner indentation moved into else if check
This also changes where the enforcement of the enable_additional_node_meta_txt configuration gets applied.
formatNodeRecord returns the main RRs and the meta/TXT RRs in separate slices. Its then up to the caller to add to the appropriate sections or not.
Update docs a little
Update/add tests. Make sure all the various ways of determining the source IP work
Update X-Forwarded-For header parsing. This can be a comma separated list with the first element being the original IP so we now handle csv data there.
Got rid of error return from sourceAddrFromRequest
Test HTTP/DNS source IP without header/extra EDNS data.
Add WARN log for when prepared query with near=_ip is executed without specifying the source ip
Queries to the DNS server can contain an optional datacenter
name in the query name. You can query for 'foo.service.consul'
or 'foo.service.dc.consul' to get a response for either the
default or a specific datacenter.
Datacenter names cannot have dots, therefore the datacenter
name can refer to only one element in the DNS query name.
The DNS server allowed extra labels between the optional
datacenter name and the domain and returned a valid response
instead of returning NXDOMAIN. For example, if the domain
is set to '.consul' then 'foo.service.dc1.extra.consul'
should return NXDOMAIN because of 'extra' being between
the datacenter name 'dc1' and the domain '.consul'.
Fixes#3200
