Resolution commands rework

[Stebalien]

1. ipfs name resolve and ipfs dns should be recursive by default, the current behavior is a surprising foot-gun. We should consider just changing this as I'm sure it'll fix significantly more bugs than it causes.
2. ipfs dns should resolve up to the first non-dnslink path by default. It shouldn't return an error when it hits a non-dnslink path, it should just return that path.

I'd also like to return a partial result when we hit the recursion limit (along with the error) but that's less pressing.

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Can anyone think of anything this would break?

@alanshaw, how will this affect JS? Is this doable?

@whyrusleeping any idea why we aren't recursive by default?

[lidel]

Can anyone think of anything this would break?

👍 for recursive by default, but given the fact we expose both commands on our public gateways, we should also implement recursion limit enabled by default (or even as a hard limit), otherwise people can easily DOS us by requesting lookup for circular IPNS links.

cc #4293 and #4181 where Lars suggested following limits from http tools:

Agreed -- probably with a sensible recursion limit (10 or so), similar to what curl/wget would do for redirects.

For the record, wget follows up to 20 redirects by default:

--max-redirect=number Specifies the maximum number of redirections to follow for a resource. The default is 20, which is usually far more than necessary. However, on those occasions where you want to allow more (or fewer), this is the option to use.
– https://www.gnu.org/software/wget/manual/html_node/HTTP-Options.html

Curl limit is 50:

--max-redirs <num> Set maximum number of redirection-followings allowed. If -L/--location is used, this option can be used to prevent curl from following redirections "in absurdum". By default, the limit is set to 50 redirections. Set this option to -1 to make it limitless.
– https://linux.die.net/man/1/curl

[alanshaw]

Same for ipfs.resolve?

[alanshaw]

I've opened an issue on the interface repo so we can track this: https://github.com/ipfs/interface-ipfs-core/issues/377

[Stebalien]

I agree, a recursion limit is a must. @whyrusleeping didn't object and can't remember why we didn't make this recursive by default either.

Note: Users can still recursively resolve using ipfs cat, etc. so this shouldn't change much from a security standpoint.