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agl
critbit
C2011–2022
agl / critbit

critbit

Critbit trees in C

Explore on GitHubRead Hacker News discussions
7Distinct people
8Mentions
0Explicit recommenders
336GitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Critbit trees in C

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:03:16 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year8 dated mentions

Observed mentions: 2011-01-16 05:10:55 UTC to 2022-07-22 10:44:10 UTC.

01232011-01-01 00:00:00 UTC to 2012-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments20112012-01-01 00:00:00 UTC to 2013-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2013-01-01 00:00:00 UTC to 2014-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2014-01-01 00:00:00 UTC to 2015-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2015-01-01 00:00:00 UTC to 2016-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments20162017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 3 mentions; 1 submissions, 2 comments2022

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20112011-01-01 00:00:00 UTC2012-01-01 00:00:00 UTC202
20122012-01-01 00:00:00 UTC2013-01-01 00:00:00 UTC000
20132013-01-01 00:00:00 UTC2014-01-01 00:00:00 UTC101
20142014-01-01 00:00:00 UTC2015-01-01 00:00:00 UTC101
20152015-01-01 00:00:00 UTC2016-01-01 00:00:00 UTC000
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC000
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC000
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC101
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC000
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC000
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC000
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC312

What Hacker News says

8 sources
ignoramous·Jul 22, 2022
> Good use-case: routing. Say you have a list of 1 million IPs that are [deny listed]. Apparently, bloom filters make for lousy IP membership checks, read: https://blog.cloudflare.com/when-bloom-filters-dont-bloom/ CritBit Trie [0] and possibly Allotment Routing Table (ART) are better suited for IPs [1]. [0] https://github.com/agl/critbit [1] https://web.archive.org/web/20210720162224/https://www.harig...
In Ask HN: What are some cool but obscure data structures you know about?
ignoramous·Jun 3, 2022
developer here In the dns-only mode, IPv6 should work. The reason for not supporting IPv6 in the firewall-mode is two fold: 1. Firewall today simply stores classless IP address rules as strings in a sqlite table fronted by a lfu cache backed by a typical hash-map. With IPv6, I'd imagine, this won't scale. So, we need a more economical in-memory data-structure (like a crit-bit trie [0] or an art tree [1]). 2. Apparently LwIP has problems with HappyEyeballs (I personally never saw it, but got a couple of reports from users about it that it was an unrecoverable error once the connectivity was lost, and the firewall had to be restarted to get internet back up). We're in the process of replacing LwIP with gvisor/netstack now [2], just to get IPv6 support back on track. --- That said, I'd imagine the app should work just fine over IPv6-only net
Read the rest
works thanks to 464xlat [3]. I may be wrong, because I've never tested it on a IPv6-only network with support for it. [0] https://github.com/agl/critbit [1] http://www.hariguchi.org/art/art.pdf [2] https://github.com/celzero/firestack/issues/3 [3] https://sites.google.com/site/tmoipv6/464xlat
In Rethink-app: DNS over HTTPS, firewall, and connection tracker for Android

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