c-ares / c-ares / #386

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Build Type

push

travis-ci

Committed by web-flow

Commit Message

Support ipv6 link-local servers and %iface syntax (#646)

Some environments may send router advertisements on a link setting their link-local (fe80::/10) address as a valid DNS server to the remote system.  This will cause a DNS entry to be created like `fe80::1%iface`, since all link-local network interfaces are technically part of the same /10 subnet, it must be told what interface to send packets through explicitly if there are multiple physical interfaces.

This PR adds support for the %iface modifier when setting DNS servers via `/etc/resolv.conf` as well as via `ares_set_servers_csv()`. 

For MacOS and iOS it is assumed that libresolve will set the `sin6_scope_id` and should be supported, but my test systems don't seem to read the Router Advertisement for RDNSS link-local.  Specifying the link-local dns server on MacOS via adig has been tested and confirmed working.

For Windows, this is similar to MacOS in that the system doesn't seem to honor the RDNSS RA, but specifying manually has been tested to work.

At this point, Android support does not exist.

Fixes Bug #462
Supersedes PR #463

Fix By: Brad House (@bradh352) and Serhii Purik (@sergvpurik)

Run Details

109 of 300 new or added lines in 6 files covered. (36.33%)

38 existing lines in 4 files now uncovered.

7696 of 9511 relevant lines covered (80.92%)

1856.74 hits per line