Whatever happened to SHA-256 support in Git? [LWN.net]

Whatever happened to SHA-256 support in Git?

Posted Jun 23, 2022 14:43 UTC (Thu) by martin.langhoff (subscriber, #61417)
Parent article: Whatever happened to SHA-256 support in Git?

The git ecosystem is vast. This is both needed, and something that'll break all sorts of stuff.

Which reminds me... how is that IPv6 transition going? :-)

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Whatever happened to SHA-256 support in Git?

Posted Jun 23, 2022 19:03 UTC (Thu) by Sesse (subscriber, #53779) [Link] (17 responses)

Around than 40% of end users (desktop or mobile) support IPv6. https://www.google.com/intl/en/ipv6/statistics.html

If you are an ISP and enable IPv6 in your network, you can expect to see more IPv6 traffic than IPv4 traffic on average.

IPv6

Posted Jun 23, 2022 19:18 UTC (Thu) by corbet (editor, #1) [Link] (12 responses)

As a highly precise and rigorous experiment that surely generalizes to the net as a whole, I did a couple of greps out of the LWN server log and found that just under 20% of our hits come from IPv6 addresses.

IPv6

Posted Jun 23, 2022 19:21 UTC (Thu) by Sesse (subscriber, #53779) [Link]

Note that if your IPv6 connectivity is significantly slower than your IPv4 connectivity (on average), clients will generally prefer IPv4 (they send SYN packets for both, and let them race, with a slight preference for IPv6).

IPv6

Posted Jun 23, 2022 20:32 UTC (Thu) by jem (subscriber, #24231) [Link] (8 responses)

I suspect IPv6 net traffic is skewed towards connections over the mobile network, with the traditional DSL connections still being IPv4-only. Maybe lwn.net readers are predominantly using computers in a traditional (home) office setting? Company networks also typically don't support IPv6, which can be seen in the graphs published by Google as spikes during the weekends.

IPv6

Posted Jun 24, 2022 1:41 UTC (Fri) by bartoc (guest, #124262) [Link] (5 responses)

IME that's not so true anymore. You will probably see more usage of stuff like NAT64 and 464xlat in mobile clients though (honestly, such schemes are not all that useful in the real world). Many, if not most wired network connections in the states support v6 native, and I don't really see why that wouldn't keep growing, nobody actually likes having to deal with cgnat, including the ISPs.

Traditional DSL connections may still use it, because most DSL infrastructure is somewhat old and not well maintained, but cable and fiber ISPs have been OK about upgrading people.

The big cloud hosting providers don't tend to support v6 for internal routing yet, which is a bit unfortunate because "just using native ipv6" would meet a lot of the container networking requirements without having to administer a BGP server (I kinda can't believe that some of these container runtimes have caught on with that requirement, it's quite heroic in a way).

IPv6

Posted Jun 24, 2022 7:28 UTC (Fri) by jem (subscriber, #24231) [Link] (4 responses)

>IME that's not so true anymore. You will probably see more usage of stuff like NAT64 and 464xlat in mobile clients though (honestly, such schemes are not all that useful in the real world).

Mobile phones are dual stack, too, just like desktop/laptop computers. An operator can choose to use NAT64 to provide IPv4 connectivity from a IPv6-only handset, but that's their choice.

Mobile technology is newer and faster moving, old landlines are in the category "they work, so don't fix them".

>Many, if not most wired network connections in the states support v6 native, and I don't really see why that wouldn't keep growing, nobody actually likes having to deal with cgnat, including the ISPs.

The ISPs will still have to support IPv4 some way or another for a long time. In practice, this means some sort of NAT.

I guess most of LWN's subscribers are from the States, so it's fair to look at the numbers from a US perspective. The percentage Google reports for the US (51%) is above the average (~40%). The top three countries are France (70%), India (64%), and Germany (64%). Then there are countries with huge populations, and even a whole continent (Africa) which are seriously lagging behind.

IPv6

Posted Jun 25, 2022 18:51 UTC (Sat) by Wol (subscriber, #4433) [Link] (3 responses)

> Mobile technology is newer and faster moving, old landlines are in the category "they work, so don't fix them".

In the UK, "old landlines" will soon be history. Our POTS here has already been upgraded to VOIP - my old POTS phone is now plugged into my broadband router and works fine (for a somewhat jaded definition of "fine" :-(

Dunno about other countries in Europe, though ...

Cheers,
Wol

IPv6

Posted Jun 25, 2022 20:05 UTC (Sat) by Sesse (subscriber, #53779) [Link] (2 responses)

Here (Norway), the copper network (POTS, ISDN, DSL) is simply left to die; a little of it is still left, but if it breaks, it won't be fixed. Nearly all voice is 2G/4G/5G (3G has largely been turned down). Data is DOCSIS (cable), FTTH or 4G/5G.

IPv6

Posted Jun 26, 2022 11:27 UTC (Sun) by jem (subscriber, #24231) [Link] (1 responses)

Deployment of IPv6 in Norway is lagging six years behind the global average, though. (Based on the aforementioned Google stats: https://www.google.com/intl/en/ipv6/statistics.html#tab=p...)

IPv6

Posted Jun 26, 2022 11:29 UTC (Sun) by Sesse (subscriber, #53779) [Link]

This is very much true, and it is largely due to the incumbent ISPs lagging. Most countries' status is usually very much driven by what key people in a few select ISPs choose to care about. :-/

IPv6

Posted Jun 24, 2022 17:04 UTC (Fri) by Lennie (subscriber, #49641) [Link] (1 responses)

Maybe lwn.net has a certain regional bias when it comes to IPv6 traffic.

IPv6

Posted Jun 27, 2022 19:25 UTC (Mon) by ceplm (subscriber, #41334) [Link]

I think the bias is that more readers are IT professionals sitting on old IPv4 networks who use IPv6 only as a back-stop.

IPv6

Posted Jun 25, 2022 4:41 UTC (Sat) by alison (subscriber, #63752) [Link]

LWN is the funniest website that I read regularly, mostly intentionally. Keep up the good work!

IPv6

Posted Jul 9, 2022 5:53 UTC (Sat) by oldtomas (guest, #72579) [Link]

Inspired by yours, I tried an equally precise and rigorous experiment. Context: bog standard (Debian Gnu-)Linux box. I moved a couple of weeks ago. In my old flat, I gave up on IPv6 (your bog standard DSL, one of ghe Big Providers around here). In my new flat (same setup, the other of the Big Providers, yes, we have more than one)... surprise:

tomas@trotzki:~$ ping lwn.net
PING lwn.net(prod3.lwn.net (2600:3c03::f03c:91ff:fe82:68b2)) 56 data bytes
64 bytes from prod3.lwn.net (2600:3c03::f03c:91ff:fe82:68b2): icmp_seq=2 ttl=56 time=102 ms
64 bytes from prod3.lwn.net (2600:3c03::f03c:91ff:fe82:68b2): icmp_seq=3 ttl=56 time=102 ms
...

So it seems it's slowly coming, not just for smartphones

Whatever happened to SHA-256 support in Git?

Posted Jun 24, 2022 19:24 UTC (Fri) by dvdeug (guest, #10998) [Link] (2 responses)

My boss insists on turning off IPv6 on all computers we install. I'm not a fan, but he's the boss, and he's had problems with it historically.

Whatever happened to SHA-256 support in Git?

Posted Jun 25, 2022 17:27 UTC (Sat) by jezuch (subscriber, #52988) [Link] (1 responses)

> problems with it historically

...and people still recommend against XFS because of a data-eating bug that was fixed in 2005 *sigh*

Whatever happened to SHA-256 support in Git?

Posted Jun 27, 2022 8:47 UTC (Mon) by taladar (subscriber, #68407) [Link]

And spout nonsense like "never change a running system" because that is what some old person told them in the 70s.

Whatever happened to SHA-256 support in Git?

Posted Jun 25, 2022 16:20 UTC (Sat) by farnz (subscriber, #17727) [Link]

One fun thing about that is that you can expect to see more IPv6 traffic by byte volume or packet count than IPv4, but not necessarily by connection count.

A thing that drives IPv6 adoption in mobile is that data-intensive services like Netflix and YouTube are IPv6-enabled - so by enabling IPv6 for your customers, you can use stateless routing to get that traffic off your backbone and onto the video provider network nearer the cell site, whereas for CGNAT (including NAT64 and 464XLAT here), you have the complexity of maintaining distributed state to handle.