+++ /dev/null
-#!/usr/bin/python3
-r"""
-Convert tinydns and dnscache logs to human-readable form
-"""
-
-import re, typing
-from struct import pack
-
-## Regular expressions for matching tinydns/dnscache log lines. We
-## compile these once here rather than within the corresponding
-## matching functions, because the latter get executed repeatedly.
-
-# This first pattern is used to match the timestamp format that the
-# tai64nlocal program produces. It appears in both dnscache and
-# tinydns lines, after they've been piped through tai64nlocal, of
-# course.
-timestamp_pat = r'[\d-]+ [\d:\.]+'
-
-# The regex to match dnscache log lines.
-dnscache_log_re = re.compile(fr'({timestamp_pat}) (\w+)(.*)')
-
-# The "hex4" pattern matches a string of four hexadecimal digits. This
-# is used, for example, by tinydns to encode the query type
-# identifier.
-hex4_pat = r'[0-9a-f]{4}'
-
-# The IP pattern matches a string of either 8 or 32 hexadecimal
-# characters, which correspond to IPv4 and IPv6 addresses,
-# respectively, in tinydns logs.
-ip_pat = r'[0-9a-f]{8,32}'
-
-# The regex to match tinydns log lines.
-tinydns_log_re = re.compile(
- rf'({timestamp_pat}) ({ip_pat}):({hex4_pat}):({hex4_pat}) ([\+\-IC/]) ({hex4_pat}) (.*)'
-)
-
-# A dictionary mapping query type identifiers, in decimal, to their
-# friendly names for tinydns. Reference:
-#
-# https://en.wikipedia.org/wiki/List_of_DNS_record_types
-#
-# Note that mapping here is non-exhaustive, and that tinydns will
-# log responses for record types that it does not know about.
-query_type = {
- 1: "a",
- 2: "ns",
- 5: "cname",
- 6: "soa",
- 12: "ptr",
- 13: "hinfo",
- 15: "mx",
- 16: "txt",
- 17: "rp",
- 24: "sig",
- 25: "key",
- 28: "aaaa",
- 33: "srv",
- 35: "naptr",
- 38: "a6",
- 48: "dnskey",
- 52: "tlsa",
- 65: "https",
- 252: "axfr",
- 255: "any",
- 257: "caa"
-}
-
-# tinydns can drop a query for one of three reasons; this dictionary
-# maps the symbol that gets logged in each case to a human-readable
-# reason. We include the "+" case here, indicating that the query was
-# NOT dropped, to avoid a special case later on when we're formatting
-# the human-readable output.
-query_drop_reason = {
- "+": None,
- "-": "no authority",
- "I": "invalid query",
- "C": "invalid class",
- "/": "couldn't parse"
-}
-
-
-def convert_ip(ip : str) -> str:
- r"""
- Convert a hex string representing an IP address to
- human-readable form.
-
- Parameters
- ----------
-
- ip : str
- The hexadecimal representation of either an IPv4 or an IPv6
- address.
-
- Returns
- -------
-
- The usual decimal dotted-quad representation is returned for an
- IPv4 address. IPv6 addresses are returned almost as-is, but with
- colons inserted in the appropriate places, between every four
- characters.
-
- Examples
- --------
-
- >>> convert_ip("7f000001")
- '127.0.0.1'
- >>> convert_ip("00000000000000000000ffff7f000001")
- '0000:0000:0000:0000:0000:ffff:7f00:0001'
- """
- if len(ip) == 8:
- # IPv4, eg. "7f000001" -> "7f 00 00 01" -> "127.0.0.1"
- return ".".join(map(str, pack(">L", int(ip, 16))))
- elif len(ip) == 32:
- # IPv6 is actually simpler -- it's just a string-slicing operation.
- return ":".join([ip[(4*i) : (4*i+4)] for i in range(8)])
-
-
-def decode_client(words : list, i : int):
- r"""
- Helper function to decode the client field in a dnscache log
- entry.
-
- There are two possible formats for the client field,
-
- 1. clientip:clientport, used by tcpopen/tcpclose entries,
- 2. clientip:clientport:id, used by "query" entries.
-
- We convert each part from hex to decimal, and in the second
- format, separate the packet id from the client information.
-
- Parameters
- ----------
-
- words : list
- The ``words`` list (a list of fields) from
- :func:`handle_dnscache_log`.
-
- i : int
- The index of the client field within ``words``
-
- Returns
- -------
-
- Nothing; the ``i``th entry in the ``words`` list is modified
- in-place.
-
- Examples
- --------
-
- >>> words = ["foo", "bar", "7f000001:9253", "quux"]
- >>> decode_client(words, 2)
- >>> words
- ['foo', 'bar', '127.0.0.1:37459', 'quux']
-
- >>> words = ["foo", "7f000001:a3db:4fb9", "bar", "quux"]
- >>> decode_client(words, 1)
- >>> words
- ['foo', '127.0.0.1:41947 (id 20409)', 'bar', 'quux']
-
- """
- chunks = words[i].split(":")
-
- ip = convert_ip(chunks[0])
- port = int(chunks[1], 16)
- words[i] = f"{ip}:{port}"
-
- if len(chunks) == 3:
- # For a "query" entry's clientip:clientport:id field.
- id = int(chunks[2], 16)
- words[i] += f" (id {id})"
-
-def decode_ip(words : list, i : int):
- r"""
- Helper function to decode the ip field in a dnscache log
- entry.
-
- A single "serverip" field is present in the lame, nodata,
- nxdomain, and rr entry types. We convert it from hex to decimal.
-
- Parameters
- ----------
-
- words : list
- The ``words`` list (a list of fields) from
- :func:`handle_dnscache_log`.
-
- i : int
- The index of the ip field within ``words``
-
- Returns
- -------
-
- Nothing; the ``i``th entry in the ``words`` list is modified
- in-place.
-
- Examples
- --------
-
- >>> words = ["foo", "bar", "7f000001", "quux"]
- >>> decode_ip(words, 2)
- >>> words
- ['foo', 'bar', '127.0.0.1', 'quux']
-
- >>> words = ["foo", "00000000000000000000ffff7f000001", "bar", "quux"]
- >>> decode_ip(words, 1)
- >>> words
- ['foo', '0000:0000:0000:0000:0000:ffff:7f00:0001', 'bar', 'quux']
- """
- words[i] = convert_ip(words[i])
-
-def decode_ttl(words : list, i : int):
- r"""
- Helper function to decode the ttl field in a dnscache log
- entry.
-
- A single "ttl" field is present in the nodata, nxdomain, and
- rr entry types. We prefix it with "TTL=" so that its meaning
- is clear in the human-readable logs.
-
- Parameters
- ----------
-
- words : list
- The ``words`` list (a list of fields) from
- :func:`handle_dnscache_log`.
-
- i : int
- The index of the ttl field within ``words``
-
- Returns
- -------
-
- Nothing; the ``i``th entry in the ``words`` list is modified
- in-place.
-
- Examples
- --------
-
- >>> words = ["c0a80101", "20865", "1", "www.example.com.", "5db8d822"]
- >>> decode_ttl(words, 1)
- >>> words
- ['c0a80101', 'TTL=20865', '1', 'www.example.com.', '5db8d822']
-
- """
- words[i] = f"TTL={words[i]}"
-
-def decode_serial(words : list, i : int):
- r"""
- Helper function to decode the serial field in a dnscache log
- entry.
-
- A single "serial" field is present in the drop and query entry
- types. It's already in decimal; we simply prefix it with a hash.
-
- Parameters
- ----------
-
- words : list
- The ``words`` list (a list of fields) from
- :func:`handle_dnscache_log`.
-
- i : int
- The index of the serial field within ``words``
-
- Returns
- -------
-
- Nothing; the ``i``th entry in the ``words`` list is modified
- in-place.
-
- Examples
- --------
-
- >>> words = ["1", "7f000001:a3db:4fb9", "1", "www.example.com."]
- >>> decode_serial(words, 0)
- >>> words
- ['#1', '7f000001:a3db:4fb9', '1', 'www.example.com.']
-
- """
- words[i] = f"#{words[i]}"
-
-def decode_type(words : list, i : int):
- qt = words[i]
- words[i] = query_type.get(int(qt), qt)
-
-def handle_dnscache_log(line : str) -> typing.Optional[str]:
- r"""
- Handle a single log line if it matches the ``dnscache_log_re`` regex.
-
- Parameters
- ----------
-
- line : string
- The log line that might match ``dnscache_log_re``.
-
- Returns
- -------
-
- Either the human-readable string if the log line was handled (that
- is, if it was really a dnscache log line), or ``None`` if it was
- not.
-
- Examples
- --------
-
- >>> line = "2022-09-15 18:37:33.863805500 query 1 7f000001:a3db:4fb9 1 www.example.com."
- >>> handle_dnscache_log(line)
- '2022-09-15 18:37:33.863805500 query #1 127.0.0.1:41947 (id 20409) a www.example.com.'
-
- >>> line = "2022-09-15 18:37:33.863874500 tx 0 1 www.example.com. . c0a80101"
- >>> handle_dnscache_log(line)
- '2022-09-15 18:37:33.863874500 tx g=0 a www.example.com. . 192.168.1.1'
-
- >>> line = "2022-09-15 18:37:33.878529500 rr c0a80101 20865 1 www.example.com. 5db8d822"
- >>> handle_dnscache_log(line)
- '2022-09-15 18:37:33.878529500 rr 192.168.1.1 TTL=20865 a www.example.com. 93.184.216.34'
-
- >>> line = "2022-09-15 18:37:33.878532500 stats 1 43 1 0"
- >>> handle_dnscache_log(line)
- '2022-09-15 18:37:33.878532500 stats count=1 motion=43 udp-active=1 tcp-active=0'
-
- >>> line = "2022-09-15 18:37:33.878602500 sent 1 49"
- >>> handle_dnscache_log(line)
- '2022-09-15 18:37:33.878602500 sent #1 49'
-
- >>> line = "this line is nonsense"
- >>> handle_dnscache_log(line)
-
- """
- match = dnscache_log_re.match(line)
- if not match:
- return None
-
- (timestamp, event, data) = match.groups()
-
- words = data.split()
- if event == "cached":
- if words[0] not in ("cname", "ns", "nxdomain"):
- decode_type(words, 0)
-
- elif event == "drop":
- decode_serial(words, 0)
-
- elif event == "lame":
- decode_ip(words, 0)
-
- elif event == "nodata":
- decode_ip(words, 0)
- decode_ttl(words, 1)
- decode_type(words, 2)
-
- elif event == "nxdomain":
- decode_ip(words, 0)
- decode_ttl(words, 1)
-
- elif event == "query":
- decode_serial(words, 0)
- decode_client(words, 1)
- decode_type(words, 2)
-
- elif event == "rr":
- decode_ip(words, 0)
- decode_ttl(words, 1)
- if words[2] not in ("cname", "mx", "ns", "ptr", "soa"):
- decode_type(words, 2)
- if words[2] == "a": # decode answer to an A query
- decode_ip(words, 4)
- if words[2] == "txt": # text record
- response = words[4]
- if response.endswith("..."):
- ellipsis = "..."
- response = response[0:-3]
- else:
- ellipsis = ""
- length = int(response[0:2], 16)
- chars = []
- for i in range(1, len(response)//2):
- chars.append(chr(int(response[2*i : (2*i)+2], 16)))
- txt = "".join(chars)
- words[4] = f"{length}:\"{txt}{ellipsis}\""
-
- elif event == "sent":
- decode_serial(words, 0)
-
- elif event == "stats":
- words[0] = f"count={words[0]}"
- words[1] = f"motion={words[1]}"
- words[2] = f"udp-active={words[2]}"
- words[3] = f"tcp-active={words[3]}"
-
- elif event == "tx":
- words[0] = f"g={words[0]}"
- decode_type(words, 1)
- # words[2] = name
- # words[3] = control (domain for which these servers are believed
- # to be authoritative)
- for i in range(4, len(words)):
- decode_ip(words, i)
-
- elif event in ("tcpopen", "tcpclose"):
- decode_client(words, 0)
-
- # Reconstitute "data" (i.e. everything after the timestamp and the
- # event) from "words", which was originally obtained by splitting
- # "data".
- data = " ".join(words)
- return f"{timestamp} {event} {data}"
-
-
-
-def handle_tinydns_log(line : str) -> typing.Optional[str]:
- r"""
- Handle a single log line if it matches the ``tinydns_log_re`` regex.
-
- Parameters
- ----------
-
- line : string
- The log line that might match ``tinydns_log_re``.
-
- Returns
- -------
-
- Either the human-readable string if the log line was handled (that
- is, if it was really a tinydns log line), or ``None`` if it was
- not.
-
- Examples
- --------
-
- >>> line = "2022-09-14 21:04:40.206516500 7f000001:9d61:be69 - 0001 www.example.com"
- >>> handle_tinydns_log(line)
- '2022-09-14 21:04:40.206516500 dropped query (no authority) from 127.0.0.1:40289 (id 48745): a www.example.com'
-
- >>> line = "this line is nonsense"
- >>> handle_tinydns_log(line)
-
- """
- match = tinydns_log_re.match(line)
- if not match:
- return None
-
- (timestamp, ip, port, id, code, type, name) = match.groups()
- ip = convert_ip(ip)
- port = int(port, 16)
- id = int(id, 16)
-
- # Convert the "type" field to a human-readable record type name
- # using the query_type dictionary. If the right name isn't present
- # in the dictionary, we use the (decimal) type id instead.
- type = int(type, 16) # "001c" -> 28
- type = query_type.get(type, type) # 28 -> "aaaa"
-
- line_tpl = "{timestamp} "
-
- reason = query_drop_reason[code]
- if code == "+":
- line_tpl += "sent response to {ip}:{port} (id {id}): {type} {name}"
- else:
- line_tpl += "dropped query ({reason}) from {ip}:{port}"
- if code != "/":
- # If the query can actually be parsed, the log line is a
- # bit more informative than it would have been otherwise.
- line_tpl += " (id {id}): {type} {name}"
-
- return line_tpl.format(timestamp=timestamp,
- reason=reason,
- ip=ip,
- port=port,
- id=id,
- type=type,
- name=name)
-
-
-def parse_logfile(file : typing.TextIO):
- r"""
- Process a single log ``file``.
-
- Parameters
- ----------
-
- file : typing.TextIO
- An open log file, or stdin.
-
- Examples
- --------
-
- >>> line = "@4000000063227a320c4f3114 7f000001:9d61:be69 - 0001 www.example.com\n"
- >>> from tempfile import NamedTemporaryFile
- >>> with NamedTemporaryFile(mode="w", delete=False) as f:
- ... _ = f.write(line)
- >>> f = open(f.name, 'r')
- >>> parse_logfile(f)
- 2022-09-14 21:04:40.206516500 dropped query (no authority) from 127.0.0.1:40289 (id 48745): a www.example.com
- >>> f.close()
- >>> from os import remove
- >>> remove(f.name)
-
- """
- # Open a pipe to tai64nlocal. We'll write lines of our input file
- # (the log file) to it, and read back the same lines but with
- # friendly timestamps in them.
- from subprocess import Popen, PIPE
- tai = Popen(["tai64nlocal"], stdin=PIPE, stdout=PIPE, text=True, bufsize=0)
-
- for line in file:
- tai.stdin.write(line)
- line = tai.stdout.readline()
-
- friendly_line = handle_tinydns_log(line)
- if not friendly_line:
- friendly_line = handle_dnscache_log(line)
- if not friendly_line:
- friendly_line = line
-
- print(friendly_line)
-
-def main():
- r"""
- The entry point to the program.
-
- This function is responsible only for parsing any command-line
- arguments, and then calling :func`parse_logfile` on them.
- """
- # Create an argument parser using the file's docsctring as its
- # description.
- from argparse import ArgumentParser, FileType
- parser = ArgumentParser(description = __doc__)
-
- # Parse zero or more positional arguments into a list of
- # "logfiles". If none are given, read from stdin instead.
- from sys import stdin
- parser.add_argument("logfiles",
- metavar="LOGFILE",
- type=FileType("r"),
- nargs="*",
- default=[stdin],
- help="djbdns logfile to process (default: stdin)")
-
- # Warning: argparse automatically opens its file arguments here,
- # and they only get closed when the program terminates. There's no
- # real benefit to closing them one-at-a-time after calling
- # parse_logfile(), because the "scarce" resource of open file
- # descriptors gets consumed immediately, before any processing has
- # happened. In other words, if you're going to run out of file
- # descriptors, it's going to happen right now.
- #
- # So anyway, don't run this on several million logfiles.
- args = parser.parse_args()
- for f in args.logfiles:
- parse_logfile(f)
-
-
-if __name__ == "__main__":
- main()
projects / djbdns-logparse.git / blobdiff