#4936 NORM Update.: enable SSL for DEFLATE compression

[Zarro Boogs per Child]

#4936: enable SSL for DEFLATE compression
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 Reporter:  robot101         |       Owner:  ApprovalForUpdate
     Type:  enhancement      |      Status:  new              
 Priority:  normal           |   Milestone:  Update.1         
Component:  telepathy-other  |     Version:                   
 Keywords:  Update.1?        |    Verified:  0                
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 Given we have issues with the roster download taking too long (#4896,
 although it's a legitimate bug which daf is currently fixing) I spent a
 bit looking into whether we could enable SSL and negotiate DEFLATE
 encryption to reduce the bandwidth burden of the XMPP server traffic. I
 patched Loudmouth to instruct GNUTLS to negotiate DEFLATE if available,
 and patched Presence Service to enable old SSL (XMPP over SSL on port
 5223, because Loudmouth 1.2.x doesn't support STARRTLS) and ignore
 certificate verification errors.

 Results are very promising, on my laptop I tested logging in to
 jabber.laptop.org and downloading the roster, then signing out, and
 measured the times and data transferred:

 Without compression:
 460k downloaded
 real    0m28.717s
 user    0m2.556s
 sys     0m0.204s

 With compression:
 104k downloaded
 real    0m19.382s
 user    0m2.600s
 sys     0m0.252s

 So, for a negligible cost in CPU time we can take the bandwidth usage at
 sign-on down to 22% of the current, and hence significantly reduce the
 sign-on time on slow links (such as "media lab 802.11" :D). The 'real'
 times are a bit inaccurate because I was ending the tests manually, but
 it's definitely faster.

 These patches have also been tested on top of Joyride on an XO too, and
 work well. The appropriate changes are to Loudmouth, which I've already
 made an SRPM which Dennis is integrating to Joyride, and to Presence
 Service which we'll include in the new release.

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Ticket URL: <http://dev.laptop.org/ticket/4936>
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