add forgotten file

1 files changed, 137 insertions, 0 deletions

diff --git a/openbsc/src/reg-proxy/sip_parser.py b/openbsc/src/reg-proxy/sip_parser.py
new file mode 100644
index 000000000..95956ae85
--- /dev/null
+++ b/openbsc/src/reg-proxy/sip_parser.py
@@ -0,0 +1,137 @@
+################################################################################
+#
+# Stand-alone VoIP honeypot client (preparation for Dionaea integration)
+# Copyright (c) 2010 Tobias Wulff (twu200 at gmail)
+#
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
+# Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+################################################################################
+
+
+import sys
+import string
+
+# SIP headers have short forms
+shortHeaders = {"call-id": "i",
+                "contact": "m",
+                "content-encoding": "e",
+                "content-length": "l",
+                "content-type": "c",
+                "from": "f",
+                "subject": "s",
+                "to": "t",
+                "via": "v",
+                                "cseq": "cseq",
+                                "accept": "accept",
+                                "user-agent": "user-agent",
+                                "max-forwards": "max-forwards",
+                                "www-authentication": "www-authentication",
+                                "authorization": "authorization",
+                                "allow": "allow",
+                                "recv-info": "recv-info",
+                                "supported": "supported"
+                }
+
+longHeaders = {}
+for k, v in shortHeaders.items():
+    longHeaders[v] = k
+del k, v
+
+class SipParsingError(Exception):
+        """Exception class for errors occuring during SIP message parsing"""
+
+def parseSipMessage(msg):
+        """Parses a SIP message (string), returns a tupel (type, firstLine, header,
+        body)"""
+        # Sanitize input: remove superfluous leading and trailing newlines and
+        # spaces
+        msg = msg.strip("\n\r\t ")
+
+        # Split request/status line plus headers and body: we don't care about the
+        # body in the SIP parser
+        parts = msg.split("\n\r\n", 1)
+        if len(parts) < 1:
+                raise SipParsingError("Message too short")
+
+        msg = parts[0]
+
+        # Python way of doing a ? b : c
+        body = len(parts) == 2 and parts[1] or parts[len(parts)-1]
+
+        # Normalize line feed and carriage return to \n
+        msg = msg.replace("\n\r", "\n")
+
+        # Split lines into a list, each item containing one line
+        lines = msg.split('\n')
+
+        # Get message type (first word, smallest possible one is "ACK" or "BYE")
+        sep = lines[0].find(' ')
+        if sep < 3:
+                raise SipParsingError("Malformed request or status line")
+
+        msgType = lines[0][:sep]
+        firstLine = lines[0][sep+1:]
+
+        # Done with first line: delete from list of lines
+        del lines[0]
+
+        # Parse header
+        headers = {}
+        for i in range(len(lines)):
+                # Take first line and remove from list of lines
+                line = lines.pop(0)
+
+                # Strip each line of leading and trailing whitespaces
+                line = line.strip("\n\r\t ")
+
+                # Break on empty line (end of headers)
+                if len(line.strip(' ')) == 0:
+                        break
+
+                # Parse header lines
+                sep = line.find(':')
+                if sep < 1:
+                        raise SipParsingError("Malformed header line (no ':')")
+
+                # Get header identifier (word before the ':')
+                identifier = line[:sep]
+                identifier = identifier.lower()
+
+                # Check for valid header
+                if identifier not in shortHeaders.keys() and \
+                        identifier not in longHeaders.keys():
+                        raise SipParsingError("Unknown header type: {}".format(identifier))
+
+                # Get long header identifier if necessary
+                if identifier in longHeaders.keys():
+                        identifier = longHeaders[identifier]
+
+                # Get header value (line after ':')
+                value = line[sep+1:].strip(' ')
+
+                # The Via header can occur multiple times
+                if identifier == "via":
+                        if identifier not in headers:
+                                headers["via"] = [value]
+                        else:
+                                headers["via"].append(value)
+
+                # Assign any other header value directly to the header key
+                else:
+                        headers[identifier] = value
+
+        # Return message type, header dictionary, and body string
+        return (msgType, firstLine, headers, body)