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suffix usageadd_diversion usageThe module implements the Diversion extensions as per draft-levy-sip-diversion-08. The diversion extensions are useful in various scenarios involving call forwarding. Typically one needs to communicate the original recipient of the call to the PSTN gateway and this is what the diversion extensions can be used for.
The draft-levy-sip-diversion-08 is expired!! See IETF I-D tracker.
The suffix to be appended to the end of the header field. You can use the parameter to specify additional parameters to be added to the header field, see the example.
Default value is “” (empty string).
The function adds a new diversion header field before any other existing Diversion header field in the message (the newly added Diversion header field will become the topmost Diversion header field). The inbound (without any modifications done by the proxy server) Request-URI will be used as the Diversion URI.
Meaning of the parameters is as follows:
reason (string) - The reason string to be added as the reason parameter
uri (string, optional) - The URI to be added in the header. If missing the unchanged RURI from the original message will be used.
counter (int, optional) - Diversion counter to be added to the header, as defined by the standard.
This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
The following example shows a Diversion header field added to INVITE message. The original INVITE received by the user agent of sip:bob@sip.org is:
INVITE sip:bob@sip.org SIP/2.0 Via: SIP/2.0/UDP 1.2.3.4:5060 From: "mark" <sip:mark@sip.org>;tag=ldgheoihege To: "Bob" <sip:bob@sip.org> Call-ID: adgasdkgjhkjha@1.2.3.4 CSeq: 3 INVITE Contact: <sip:mark@1.2.3.4> Content-Length: 0
The INVITE message is diverted by the user agent of sip:bob@sip.org because the user was talking to someone else and the new destination is sip:alice@sip.org :
INVITE sip:alice@sip.org SIP/2.0 Via: SIP/2.0/UDP 5.6.7.8:5060 Via: SIP/2.0/UDP 1.2.3.4:5060 From: "mark" <sip:mark@sip.org>;tag=ldgheoihege To: "Bob" <sip:bob@sip.org> Call-ID: adgasdkgjhkjha@1.2.3.4 CSeq: 3 INVITE Diversion: <sip:bob@sip.org>;reason=user-busy Contact: <sip:mark@1.2.3.4> Content-Length: 0
According to the specification new Diversion header field should be inserted as the topmost
Diversion header field in the message, that means before any other existing Diversion header
field in the message. In addition to that, add_diversion function can be called several times and each time
it should insert the new Diversion header field as the topmost one.
In order to implement this, add_diversion function creates the anchor in data_lump lists as a static variable to ensure that the next call of the function will use the same anchor and would insert new Diversion headers before the one created in the previous execution. To my knowledge this is the only way of inserting the diversion header field before any other created in previous runs of the function.
The anchor kept this way is only valid for a single message and we have to invalidate it when another message is being processed. For this reason, the function also stores the id of the message in another static variable and compares the value of that variable with the id of the SIP message being processed. If they differ then the anchor will be invalidated and the function creates a new one.
The following code snippet shows the code that invalidates the anchor, new anchor will be
created when the anchor variable is set to 0.
static inline int add_diversion_helper(struct sip_msg* msg, str* s)
{
static struct lump* anchor = 0;
static int msg_id = 0;
if (msg_id != msg->id) {
msg_id = msg->id;
anchor = 0;
}
...
}
Table 3.1. Top contributors by DevScore(1), authored commits(2) and lines added/removed(3)
| Name | DevScore | Commits | Lines ++ | Lines -- | |
|---|---|---|---|---|---|
| 1. | Bogdan-Andrei Iancu (@bogdan-iancu) | 17 | 15 | 62 | 32 |
| 2. | Daniel-Constantin Mierla (@miconda) | 15 | 13 | 28 | 20 |
| 3. | Liviu Chircu (@liviuchircu) | 11 | 9 | 16 | 47 |
| 4. | Jan Janak (@janakj) | 10 | 4 | 528 | 13 |
| 5. | Razvan Crainea (@razvancrainea) | 6 | 4 | 4 | 2 |
| 6. | Vlad Patrascu (@rvlad-patrascu) | 5 | 3 | 20 | 42 |
| 7. | Henning Westerholt (@henningw) | 5 | 3 | 3 | 27 |
| 8. | Saúl Ibarra Corretgé (@saghul) | 4 | 2 | 74 | 11 |
| 9. | Maksym Sobolyev (@sobomax) | 4 | 2 | 2 | 3 |
| 10. | Konstantin Bokarius | 3 | 1 | 3 | 5 |
All remaining contributors: Peter Lemenkov (@lemenkov), Edson Gellert Schubert, Andreas Heise, Vlad Paiu (@vladpaiu).
(1) DevScore = author_commits + author_lines_added / (project_lines_added / project_commits) + author_lines_deleted / (project_lines_deleted / project_commits)
(2) including any documentation-related commits, excluding merge commits. Regarding imported patches/code, we do our best to count the work on behalf of the proper owner, as per the "fix_authors" and "mod_renames" arrays in opensips/doc/build-contrib.sh. If you identify any patches/commits which do not get properly attributed to you, please submit a pull request which extends "fix_authors" and/or "mod_renames".
(3) ignoring whitespace edits, renamed files and auto-generated files
Table 3.2. Most recently active contributors(1) to this module
| Name | Commit Activity | |
|---|---|---|
| 1. | Liviu Chircu (@liviuchircu) | Mar 2014 - May 2024 |
| 2. | Maksym Sobolyev (@sobomax) | Feb 2023 - Feb 2023 |
| 3. | Razvan Crainea (@razvancrainea) | Aug 2015 - Sep 2019 |
| 4. | Vlad Patrascu (@rvlad-patrascu) | May 2017 - Apr 2019 |
| 5. | Bogdan-Andrei Iancu (@bogdan-iancu) | Jul 2005 - Apr 2019 |
| 6. | Peter Lemenkov (@lemenkov) | Jun 2018 - Jun 2018 |
| 7. | Vlad Paiu (@vladpaiu) | Jun 2012 - Jun 2012 |
| 8. | Saúl Ibarra Corretgé (@saghul) | May 2012 - Jun 2012 |
| 9. | Henning Westerholt (@henningw) | Apr 2007 - May 2008 |
| 10. | Daniel-Constantin Mierla (@miconda) | Oct 2005 - Mar 2008 |
All remaining contributors: Konstantin Bokarius, Edson Gellert Schubert, Andreas Heise, Jan Janak (@janakj).
(1) including any documentation-related commits, excluding merge commits
Last edited by: Vlad Patrascu (@rvlad-patrascu), Peter Lemenkov (@lemenkov), Liviu Chircu (@liviuchircu), Bogdan-Andrei Iancu (@bogdan-iancu), Saúl Ibarra Corretgé (@saghul), Daniel-Constantin Mierla (@miconda), Konstantin Bokarius, Edson Gellert Schubert, Jan Janak (@janakj).
Documentation Copyrights:
Copyright © 2004 FhG FOKUS