Add log parsing script for sslsplit -L

Add contributed script to read and parse the output of sslsplit -L from
a named pipe or log file and post-process the logged connection data
programmatically from python.

Issue:		#27
Contributed by:	Maciej Kotowicz

extra/logreader.py

@@ -0,0 +1,92 @@
+#!/usr/bin/env python
+# vim: set list et ts=8 sts=4 sw=4 ft=python:
+
+# SSLsplit contributed code:  Log parser for sslsplit -L
+# This script reads the log from standard input and parses it.
+# Standard input can point to a file or a named pipe.
+
+# Copyright (c) 2015, Maciej Kotowicz <mak@lokalhost.pl>
+# Copyright (c) 2015, Daniel Roethlisberger <daniel@roe.ch>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions, and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import sys
+import os
+import select
+import re
+
+def read_line(f):
+    """Read a single line from a file stream; return empty string on EOF"""
+    buf = ''
+    while not buf.endswith("\n"):
+        r, w, e = select.select([f], [], [])
+        if r:
+            nextbyte = f.read(1)
+            if not nextbyte:
+                return ''
+            buf += nextbyte
+        else:
+            break
+    return buf
+
+def read_count(f, n):
+    """Read n bytes from a file stream; return empty string on EOF"""
+    buf = ''
+    while len(buf) < n:
+        nextchunk = f.read(n - len(buf))
+        if not nextchunk:
+            return ''
+        buf += nextchunk
+    return buf
+
+class LogSyntaxError(Exception):
+    """SSLsplit log file contains unexpected syntax"""
+    pass
+
+def parse_header(line):
+    """Parse the header line into a dict with useful fields"""
+    # 2015-09-27 14:55:41 UTC [192.0.2.1]:56721 -> [192.0.2.2]:443 (37):
+    m = re.match(r'(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2} \S+) \[(.+?)\]:(\d+) -> \[(.+?)\]:(\d+) \((\d+)\):', line)
+    if not m:
+        raise LogSyntaxError(line)
+    res = {}
+    res['timestamp'] = m.group(1)
+    res['src_addr'] = m.group(2)
+    res['src_port'] = int(m.group(3))
+    res['dst_addr'] = m.group(4)
+    res['dst_port'] = int(m.group(5))
+    res['size'] = int(m.group(6))
+    return res
+
+def parse_log(f):
+    """Read log entries from file stream in blocking mode until EOF"""
+    while True:
+        line = read_line(f)
+        if not line:
+            break
+        res = parse_header(line)
+        res['data'] = read_count(f, res['size'])
+        yield res
+
+if __name__ == '__main__':
+    for result in parse_log(sys.stdin):
+        print result
+