$Revision: 1.2 $
$Date: 2004/08/24 08:58:31 $
User's Guide
Overview
This is a module to help with &sdp; mangling.
Still in testing.
Dependencies
&ser; Modules
The following modules must be loaded before this module:
No dependencies on other &ser; modules.
External Libraries or Applications
The following libraries or applications must be installed before running
&ser; with this module loaded:
None.
Exported Parameters
<varname>contact_flds_separator</varname> (string)
First char of this parameter is used as separator for encoding/decoding Contact
header.
First char of this field must be set to a value which is not used inside
username,password or other fields of contact.Otherwise it is possible for the
decoding step to fail/produce wrong results.
Default value is *
.
Set <varname>db_url</varname> parameter
...
modparam("module", "contact_flds_separator", "-")
...
then an encoded uri might look sip:user-password-ip-port-protocol@PublicIP
Exported Functions
<function moreinfo="none">sdp_mangle_ip(pattern, newip)</function>
Changes &ip; addresses inside &sdp; package in lines describing connections like
c=IN IP4 Currently in only changes IP4 addresses since IP6 probably will not need to
traverse NAT :)
The function returns negative on error, or number of replacements + 1.
Meaning of the parameters is as follows:
pattern - A pair ip/mask used to match &ip;'s located
inside &sdp; package in lines c=IN IP4 ip. This lines will only be mangled
if located &ip; is in the network described by this pattern. Examples of
valid patterns are 10.0.0.0/255.0.0.0
or
10.0.0.0/8
etc.
newip - A string representing the new &ip; to be put
inside &sdp; package if old &ip; address matches pattern.
<function>sdp_mangle_ip</function> usage
...
sdp_mangle_ip("10.0.0.0/8","193.175.135.38");
...
<function moreinfo="none">sdp_mangle_port(offset)</function>
Changes ports inside &sdp; package in lines describing media like m=audio 13451.
The function returns negative on error, or number of replacements + 1.
Meaning of the parameters is as follows:
offset - A string representing an integer which will
be added/subtracted from the located port.
<function>sdp_mangle_port</function> usage
...
sdp_mangle_port("-12000");
...
<function moreinfo="none">encode_contact(encoding_prefix)</function>
This function will encode uri-s inside Contact header in the following manner
sip:username:password@ip:port;transport=protocol goes
sip:enc_pref*username*ip*port*protocol@public_ip * is the default separator.
The function returns negative on error, 1 on success.
Meaning of the parameters is as follows:
encoding_prefix - Something to allow us to determine
that a contact is encoded publicip--a routable &ip;,most probably you should
put your external &ip; of your &nat; box.
<function>encode_contact</function> usage
...
if (src_ip == 10.0.0.0/8) encode_contact("enc_prefix","193.175.135.38");
...
<function moreinfo="none">decode_contact()</function>
This function will decode the &uri; in first line in packets which come with encoded
&uri; in the following manner sip:enc_pref*username*ip*port*protocol@public_ip goes to
sip:username:password@ip:port;transport=protocol It uses the default set parameter
for contact encoding separator.
The function returns negative on error, 1 on success.
Meaning of the parameters is as follows:
<function>decode_contact</function> usage
...
if (uri =~ "^enc*") { decode_contact(); }
...
<function moreinfo="none">decode_contact_header()</function>
This function will decode &uri;s inside Contact header in the following manner
sip:enc_pref*username*ip*port*protocol@public_ip goes to
sip:username:password@ip:port;transport=protocol. It uses the default set parameter
for contact encoding separator.
The function returns negative on error, 1 on success.
Meaning of the parameters is as follows:
<function>decode_contact_header</function> usage
...
if (uri =~ "^enc*") { decode_contact_header(); }
...