Adds -x / --pre_auth_proc parameter which allows for a user to specify

a routine (a class really) that B2BUA will execute after call controller
is initialized but before any actions are taken.

Examples of such routine is one that extracts a specific header,
does some simple parsing and adds its contents as radius attribute/value
pairs.

The syntax for that routine would be something like the following:

  --pre_auth_proc=HDR2Xattrs[X-foo-hdr]

PR: #38

sippy/B2BTransforms.py

@@ -0,0 +1,54 @@
+# Copyright (c) 2024 Sippy Software, Inc. All rights reserved.
+#
+# All rights reserved.
+#
+# 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
+
+from sippy.SipRequest import SipRequest
+
+class HDR2Xattrs():
+    # Source: https://github.com/sippy/b2bua/pull/38
+    # Author: @twmobius
+    hdr_name:str
+    def __init__(self, hdr_name:str):
+        self.hdr_name = hdr_name
+
+    def __call__(req:SipRequest, cc:'CallController'):
+        hfs = req.getHFs(self.hdr_name)
+
+        if len(hfs) == 0:
+            return
+
+        extra_attributes = []
+
+        for header in hfs:
+            kvPairs = header.body.body.split(';')
+            for pair in kvPairs:
+                [key, _, value] = pair.partition("=")
+                if value != '':
+                    extra_attributes.append((key, value))
+        if len(extra_attributes) == 0:
+            return
+        if cc.extra_attributes is None:
+            cc.extra_attributes = extra_attributes
+        else:
+            cc.extra_attributes.extend(extra_attributes)

sippy/MyConfigParser.py

@@ -33,6 +33,7 @@
     from configparser import RawConfigParser
     _boolean_states = RawConfigParser.BOOLEAN_STATES
 from sippy.SipConf import SipConf
+import sippy.B2BTransforms as bts
 
 SUPPORTED_OPTIONS = { \
  'acct_enable':       ('B', 'enable or disable Radius accounting'), \
@@ -103,6 +104,8 @@
                              '"host:port:cert_file:key_file", where "cert_file" ' \
                              '/ "key_file" are paths to the TLS certificate ' \
                              'and key file respectively in the X.509 PEM format'),
+ 'pre_auth_proc': ('S', 'internal routine to be executed before authentication '\
+                        'is being processed. E.g. "HDR2Xattrs[X-foo-hdr]."'), \
  'xmpp_b2bua_id':     ('I', 'ID passed to the XMPP socket server')}
 
 class MyConfigParser(RawConfigParser):
@@ -216,6 +219,14 @@ def check_and_set(self, key, value, compat = True):
             if _value <= 0 or _value > 65535:
                 raise ValueError('sip_port should be in the range 1-65535')
             self['_sip_port'] = _value
+        elif key == 'pre_auth_proc':
+            rparts = value.split('[', 1)
+            if not len(rparts) == 2 or not value.endswith(']'):
+                raise ValueError('pre_auth_proc should be in the format `function(argument)`')
+            fname = rparts[0]
+            fclass = getattr(bts, fname)
+            farg = rparts[1][:-1]
+            self['_pre_auth_proc'] = fclass(farg)
         self[key] = value
 
     def options_help(self):

sippy/b2bua_radius.py

@@ -132,6 +132,7 @@ class CallController(object):
     challenge = None
     req_source: str
     req_target: SipURL
+    extra_attributes = None
 
     def __init__(self, remote_ip, source, req_source, req_target, global_config, pass_headers):
         self.id = CallController.id
@@ -213,11 +214,12 @@ def recvEvent(self, event, ua):
                 elif auth == None or auth.username == None or len(auth.username) == 0:
                     self.username = self.remote_ip
                     self.auth_proc = self.global_config['_radius_client'].do_auth(self.remote_ip, self.cli, self.cld, \
-                      self.cId, self.remote_ip, self.rDone)
+                      self.cId, self.remote_ip, self.rDone, extra_attributes=self.extra_attributes)
                 else:
                     self.username = auth.username
                     self.auth_proc = self.global_config['_radius_client'].do_auth(auth.username, self.cli, self.cld, \
-                      self.cId, self.remote_ip, self.rDone, auth.realm, auth.nonce, auth.uri, auth.response)
+                      self.cId, self.remote_ip, self.rDone, auth.realm, auth.nonce, auth.uri, auth.response, \
+                      extra_attributes=self.extra_attributes)
                 return
             if self.state not in (CCStateARComplete, CCStateConnected, CCStateDisconnecting) or self.uaO == None:
                 return
@@ -511,6 +513,10 @@ def recvRequest(self, req, sip_t):
                     pass_headers.extend(hfs)
             req_target = req.getRURI()
             cc = CallController(remote_ip, source, req_source, req_target, self.global_config, pass_headers)
+
+            if '_pre_auth_proc' in self.global_config:
+                self.global_config['_pre_auth_proc'](req, cc)
+
             cc.challenge = challenge
             rval = cc.uaA.recvRequest(req, sip_t)
             self.ccmap.append(cc)
@@ -715,7 +721,7 @@ def main_func():
     global_config['_orig_argv'] = sys.argv[:]
     global_config['_orig_cwd'] = os.getcwd()
     try:
-        opts, args = getopt.getopt(sys.argv[1:], 'fDl:p:d:P:L:s:a:t:T:k:m:A:ur:F:R:h:c:M:HC:W:',
+        opts, args = getopt.getopt(sys.argv[1:], 'fDl:p:d:P:L:s:a:t:T:k:m:A:ur:F:R:h:c:M:HC:W:x:',
           global_config.get_longopts())
     except getopt.GetoptError:
         usage(global_config)
@@ -807,6 +813,9 @@ def main_func():
             for a in a.split(','):
                 global_config.check_and_set('pass_header', a)
             continue
+        if o == '-x':
+            global_config.check_and_set('pre_auth_proc', a)
+            continue
         if o == '-c':
             global_config.check_and_set('b2bua_socket', a)
             continue