[MESOS-9338] Add asynchronous DNS facilities to libprocess.

• Type: Improvement
• Status: Accepted
• Priority: Major
• Resolution: Unresolved
• Component/s: libprocess
• Labels: foundations
• Assignee: Unassigned
• Reporter: Benjamin Mahler
• Created: 21/Oct/18 22:33
• Updated: 05/Jan/19 01:27

Description

This would enable non-blocking DNS queries. One use case is during TLS peer certificate verification, we need to perform a reverse DNS lookup to get the peer's hostname. This blocks the event loop thread!

Some options:

(1) Linux provides getaddrinfo_a, however I don't see an equivalent one for getnameinfo:
http://man7.org/linux/man-pages/man3/getaddrinfo_a.3.html

(2) A popular library is c-ares (MIT license):
https://c-ares.haxx.se/

(3) ADNS (GPLv3):
https://www.gnu.org/software/adns/

(4) c-ares has a list of other libraries:
https://c-ares.haxx.se/otherlibs.html

Issue Links

• blocks: MESOS-9339 SSL (TLS) peer reverse DNS lookup can block the event loop thread.
• relates to: MESOS-9505 `make check` failed with linking errors when c-ares is installed.