add scripts for generating communities json

contrib/print_communities.py

@@ -0,0 +1,192 @@
+import glob
+import json
+import math
+import os
+import re
+import sys
+
+# range regex code vendored from
+# https://github.com/zhfreal/range-regex/blob/ccd5c5c89410ec5062bfb74e627788e7b31dd56f/range_regex/range_regex.py
+# Copyright (c) 2013, Dmitry Voronin
+# BSD 2-Clause "Simplified" License
+
+def regex_for_range(min_, max_):
+    """
+    > regex_for_range(12, 345)
+    '1[2-9]|[2-9]\d|[1-2]\d{2}|3[0-3]\d|34[0-5]'
+    """
+    positive_subpatterns = []
+    negative_subpatterns = []
+
+    if min_ < 0:
+        min__ = 1
+        if max_ < 0:
+            min__ = abs(max_)
+        max__ = abs(min_)
+
+        negative_subpatterns = split_to_patterns(min__, max__)
+        min_ = 0
+
+    if max_ >= 0:
+        positive_subpatterns = split_to_patterns(min_, max_)
+
+    negative_only_subpatterns = ['-' + val for val in negative_subpatterns if val not in positive_subpatterns]
+    positive_only_subpatterns = [val for val in positive_subpatterns if val not in negative_subpatterns]
+    intersected_subpatterns = ['-?' + val for val in negative_subpatterns if val in positive_subpatterns]
+
+    subpatterns = negative_only_subpatterns + intersected_subpatterns + positive_only_subpatterns
+    return '|'.join(subpatterns)
+
+
+def split_to_patterns(min_, max_):
+    subpatterns = []
+
+    start = min_
+    for stop in split_to_ranges(min_, max_):
+        subpatterns.append(range_to_pattern(start, stop))
+        start = stop + 1
+
+    return subpatterns
+
+
+def split_to_ranges(min_, max_):
+    stops = {max_}
+
+    nines_count = 1
+    stop = fill_by_nines(min_, nines_count)
+    while min_ <= stop < max_:
+        stops.add(stop)
+
+        nines_count += 1
+        stop = fill_by_nines(min_, nines_count)
+
+    zeros_count = 1
+    stop = fill_by_zeros(max_ + 1, zeros_count) - 1
+    while min_ < stop <= max_:
+        stops.add(stop)
+
+        zeros_count += 1
+        stop = fill_by_zeros(max_ + 1, zeros_count) - 1
+
+    stops = list(stops)
+    stops.sort()
+
+    return stops
+
+
+def fill_by_nines(integer, nines_count):
+    return int(str(integer)[:-nines_count] + '9' * nines_count)
+
+
+def fill_by_zeros(integer, zeros_count):
+    return integer - integer % 10 ** zeros_count
+
+
+def range_to_pattern(start, stop):
+    pattern = ''
+    any_digit_count = 0
+
+    for start_digit, stop_digit in zip(str(start), str(stop)):
+        if start_digit == stop_digit:
+            pattern += start_digit
+        elif start_digit != '0' or stop_digit != '9':
+            pattern += '[{}-{}]'.format(start_digit, stop_digit)
+        else:
+            any_digit_count += 1
+
+    if any_digit_count:
+        pattern += r'\d'
+
+    if any_digit_count > 1:
+        pattern += '{{{}}}'.format(any_digit_count)
+
+    return pattern
+
+
+# Code derived from NLNOG RING looking glass code
+# Copyright (c) 2022 Stichting NLNOG <[email protected]>
+# ISC License
+
+def is_regular_community(community: str) -> bool:
+    """ check if a community string matches a regular community, with optional ranges
+    """
+    re_community = re.compile(r"^[\w\-]+:[\w\-]+$")
+    return re_community.match(community)
+
+
+def is_large_community(community: str) -> bool:
+    """ check if a community string matches a large community, with optional ranges
+    """
+    re_large = re.compile(r"^[\w\-]+:[\w\-]+:[\w\-]+$")
+    return re_large.match(community)
+
+
+def is_extended_community(community: str) -> bool:
+    """ check if a community string is an extended community, with optional ranges
+    """
+    re_extended = re.compile(r"^\w+ [\w\-]+(:[\w\-]+)?$")
+    return re_extended.match(community)
+
+
+def get_community_type(community: str) -> str:
+    """ determine the community type of a community.
+    """
+    if is_regular_community(community):
+        return "regular"
+    if is_large_community(community):
+        return "large"
+    if is_extended_community(community):
+        return "extended"
+
+    print(f"unknown community type for '{community}'", file=sys.stderr)
+    return "unknown"
+
+def read_communities() -> dict:
+    """ Read the list of community definitions from communities/*.txt and translate them
+        into a dictionary containing community lists for exact matches, ranges and regexps.
+    """
+    communitylist = {
+        "regular": {},
+        "large": {},
+        "extended": {},
+    }
+    re_range = re.compile(r"(\d+)\-(\d+)")
+    re_regular_exact = re.compile(r"^\d+:\d+$")
+    re_large_exact = re.compile(r"^\d+:\d+:\d+$")
+    re_extended_exact = re.compile(r"^\w+ \w+(:\w+)$")
+
+    files = glob.glob(f"{sys.argv[1]}/*.txt")
+    for filename in files:
+        with open(filename, "r", encoding="utf8") as filehandle:
+            as_name = os.path.basename(filename).replace("as", "AS").removesuffix(".txt")
+            for entry in [line.strip() for line in filehandle.readlines()]:
+                if entry.startswith("#") or "," not in entry:
+                    continue
+                (comm, desc) = entry.split(",", 1)
+                desc = f"{as_name}: {desc}"
+                ctype = get_community_type(comm)
+                if ctype == "unknown":
+                    print(f"unknown communtity format: '{comm}'", file=sys.stderr)
+                    continue
+
+                # funky notations:
+                # nnn -> any number
+                # x -> any digit
+                # a-b -> numeric range a upto b
+                comm = comm.lower()
+                while "nnn" in comm:
+                    comm = comm.replace("nnn", "(\d+)")
+                while "x" in comm:
+                    comm = comm.replace("x", "(\d)")
+                while re_range.match(comm):
+                    match = re_range.search(comm)
+                    all, first, last = match.group(0), int(match.group(1)), int(match.group(2))
+                    if first > last:
+                        print(f"Bad range for as {comm}, {first} should be less than {last}", file=sys.stderr)
+                        continue
+                    comm = comm.replace(all, regex_for_range(first, last))
+                communitylist[ctype][comm] = desc
+
+    return communitylist
+
+print(json.dumps(read_communities()))

flake.nix

@@ -4,9 +4,22 @@
 
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
   inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.communities.url = "github:NLNOG/lg.ring.nlnog.net";
+  inputs.communities.flake = false;
 
-  outputs = { self, nixpkgs, flake-utils }: {
+  outputs = { self, nixpkgs, flake-utils, communities }: {
     overlays.default = final: prev: {
+
+      communities-json = final.callPackage (
+        { runCommand, python3, jq }:
+
+        runCommand "communities.json" {
+          nativeBuildInputs = [ python3 jq ];
+        } ''
+          python3 ${./contrib/print_communities.py} ${communities}/communities | jq . > $out
+        ''
+      ) { };
+
       fernglas = final.callPackage (
         { lib, stdenv, rustPlatform }:
 
@@ -240,7 +253,7 @@
     };
   in rec {
     packages = {
-      inherit (pkgs) fernglas fernglas-frontend;
+      inherit (pkgs) fernglas fernglas-frontend communities-json;
       default = packages.fernglas;
     };
     legacyPackages = pkgs;