registrar Module
     __________________________________________________________

   Table of Contents

   1. Admin Guide

        1.1. Overview

              1.1.1. PATH support
              1.1.2. GRUU support

        1.2. Dependencies

              1.2.1. OpenSIPS Modules
              1.2.2. External Libraries or Applications

        1.3. Exported Parameters

              1.3.1. default_expires (integer)
              1.3.2. min_expires (integer)
              1.3.3. max_expires (integer)
              1.3.4. default_q (integer)
              1.3.5. tcp_persistent_flag (integer)
              1.3.6. realm_prefix (string)
              1.3.7. case_sensitive (integer)
              1.3.8. received_avp (str)
              1.3.9. received_param (string)
              1.3.10. max_contacts (integer)
              1.3.11. retry_after (integer)
              1.3.12. sock_hdr_name (string)
              1.3.13. mcontact_avp (string)
              1.3.14. attr_avp (string)
              1.3.15. gruu_secret (string)
              1.3.16. disable_gruu (int)

        1.4. Exported Functions

              1.4.1. save(domain[, flags[, aor[, ownership_tag]]])

              1.4.2. remove(domain, AOR[, [contact][, [next_hop][,
                      [sip_instance]]]])

              1.4.3. lookup(domain [, flags [, aor]])
              1.4.4. is_registered(domain ,[AOR])
              1.4.5. is_contact_registered(domain
                      ,[AOR],[contact],[callid])

              1.4.6. is_ip_registered(domain ,[AOR],IPvar)
              1.4.7. add_sock_hdr(hdr_name)

        1.5. Exported Statistics

              1.5.1. max_expires
              1.5.2. max_contacts
              1.5.3. defaults_expires
              1.5.4. accepted_regs
              1.5.5. rejected_regs

   2. Frequently Asked Questions
   3. Contributors

        3.1. By Commit Statistics
        3.2. By Commit Activity

   4. Documentation

        4.1. Contributors

   List of Tables

   3.1. Top contributors by DevScore^(1), authored commits^(2) and
          lines added/removed^(3)

   3.2. Most recently active contributors^(1) to this module

   List of Examples

   1.1. Set default_expires parameter
   1.2. Set min_expires parameter
   1.3. Set max_expires parameter
   1.4. Set default_q parameter
   1.5. Set tcp_persistent_flag parameter
   1.6. Set realm_prefix parameter
   1.7. Set case_sensitive parameter
   1.8. Set received_avp parameter
   1.9. Set received_param parameter
   1.10. Set max_contacts parameter
   1.11. Set retry_after parameter
   1.12. Set sock_hdr_namer parameter
   1.13. Set mcontact_avp parameter
   1.14. Set attr_avp parameter
   1.15. Set gruu_secret parameter
   1.16. Set gruu_secret parameter
   1.17. save usage
   1.18. remove usage
   1.19. lookup usage
   1.20. is_registered usage
   1.21. is_contact_registered usage
   1.22. is_ip_registered usage
   1.23. add_sock_hdr usage

Chapter 1. Admin Guide

1.1. Overview

   The module contains REGISTER processing logic.

1.1.1. PATH support

   Register module includes Path support (according to RFC 3327)
   for usage in registrars and home-proxies.

   A call to save(...) stores, if path-support is enabled in the
   registrar-module, the values of the Path Header(s) along with
   the contact into usrloc. There are three modes regarding the
   reply to a REGISTER including one or more Path HFs:
     * off - stores the value of the Path headers into usrloc
       without passing it back to the UAC in the reply.
     * lazy - stores the Path header and passes it back to the UAC
       if Path-support is indicated by the “path” param in the
       Supported HF.
     * strict - rejects the registration with “420 Bad Extension”
       if there's a Path header but no support for it is indicated
       by the UAC. Otherwise it's stored and passed back to the
       UAC.

   A call to lookup(...) always uses the path header if found, and
   inserts it as Route HF either in front of the first Route HF,
   or after the last Via HF if no Route is present. It also sets
   the destination uri to the first Path uri, thus overwriting the
   received-uri, because NAT has to be handled at the
   outbound-proxy of the UAC (the first hop after client's NAT).

   The whole process is transparent to the user, so no config
   changes are required beside setting the registrar-parameters
   “use_path” and “path_mode”.

1.1.2. GRUU support

   Register module includes GRUU support (according to RFC 5627)
   for usage in registrars and home-proxies.

   A call to save(...) stores, if the phone supports GRUU, the
   values of the SIP Instance along with the contact into usrloc.
   The registrar module will generate two types of GRUUs :
     * public - exposes the underlying AOR, constructed just by
       attaching the SIP Instance as the ;gr parameter value.
       These are persistent, valid as long as the contact
       registration is valid.
     * temporary - hides the underlying AOR Each new Register
       request leads to the construction of a new temporary GRUU,
       while Register requests with a different Call-Id lead to
       the invalidation of all the previous generated temporary
       GRUUs.

   A call to lookup(...) will try to detect if the R-URI contains
   a GRUU. If it does, it will route the request just for the
   Contact that the specific AOR belongs to, without appending any
   other branches.

   Even if the the GRUU handling during the registration process
   is transparent to the user, so no config changes are required,
   you need to take care of the GRUU specifics when handling the
   sequential requests.

   As the GRUU will be present in the contact header of the
   initial requests generated byt GRUU enabled devices, you will
   have to also do a lookup(..) when receiving a sequential
   request with the GRUU indication in the RURI.

1.2. Dependencies

1.2.1. OpenSIPS Modules

   The following modules must be loaded before this module:
     * usrloc - User Location Module.
     * signaling - Signaling module.

1.2.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running OpenSIPS with this module loaded:
     * None.

1.3. Exported Parameters

1.3.1. default_expires (integer)

   If the processed message contains neither Expires HFs nor
   expires contact parameters, this value will be used for newly
   created usrloc records. The parameter contains number of second
   to expire (for example use 3600 for one hour).

   Default value is 3600.

   Example 1.1. Set default_expires parameter
...
modparam("registrar", "default_expires", 1800)
...

1.3.2. min_expires (integer)

   The minimum expires value of a Contact, values lower than this
   minimum will be automatically set to the minimum. Value 0
   disables the checking.

   Default value is 60.

   Example 1.2. Set min_expires parameter
...
modparam("registrar", "min_expires", 60)
...

1.3.3. max_expires (integer)

   The maximum expires value of a Contact, values higher than this
   maximum will be automatically set to the maximum. Value 0
   disables the checking.

   Default value is 0.

   Example 1.3. Set max_expires parameter
...
modparam("registrar", "max_expires", 120)
...

1.3.4. default_q (integer)

   The parameter represents default q value for new contacts.
   Because OpenSIPS doesn't support float parameter types, the
   value in the parameter is divided by 1000 and stored as float.
   For example, if you want default_q to be 0.38, use value 380
   here.

   Default value is 0.

   Example 1.4. Set default_q parameter
...
modparam("registrar", "default_q", 1000)
...

1.3.5. tcp_persistent_flag (integer)

   The parameter specifies the message flag to be used to control
   the module behaviour regarding TCP connections. If the flag is
   set for a REGISTER via TCP containing a TCP contact, the
   module, via the “save()” function, will set the lifetime of the
   TCP connection to the contact expire value. By doing this, the
   TCP connection will stay on as long as the contact is valid.

   Default value is -1 (disabled).

   Example 1.5. Set tcp_persistent_flag parameter
...
modparam("registrar", "tcp_persistent_flag", 7)
...

1.3.6. realm_prefix (string)

   Prefix to be automatically strip from realm. As an alternative
   to SRV records (not all SIP clients support SRV lookup), a
   subdomain of the master domain can be defined for SIP purposes
   (like sip.mydomain.net pointing to same IP address as the SRV
   record for mydomain.net). By ignoring the realm_prefix "sip.",
   at registration, sip.mydomain.net will be equivalent to
   mydomain.net .

   Default value is NULL (none).

   Example 1.6. Set realm_prefix parameter
...
modparam("registrar", "realm_prefix", "sip.")
...

1.3.7. case_sensitive (integer)

   If set to 1 then AOR comparison will be case sensitive (as
   RFC3261 instructs), if set to 0 then AOR comparison will be
   case insensitive.

   Default value is 1.

   Example 1.7. Set case_sensitive parameter
...
modparam("registrar", "case_sensitive", 0)
...

1.3.8. received_avp (str)

   Registrar will store the value of the AVP configured by this
   parameter in the received column in the user location database.
   It will leave the column empty if the AVP is empty. The AVP
   should contain a SIP URI consisting of the source IP, port, and
   protocol of the REGISTER message being processed.

Note

   The value of this parameter should be the same as the value of
   corresponding parameter of nathelper module.

   Default value is "NULL" (disabled).

   Example 1.8. Set received_avp parameter
...
modparam("registrar", "received_avp", "$avp(rcv)")
...

1.3.9. received_param (string)

   The name of the parameter that will be appended to Contacts of
   200 OK when the received URI was set by nathelper module.

   Default value is "received".

   Example 1.9. Set received_param parameter
...
modparam("registrar", "received_param", "rcv")
...

1.3.10. max_contacts (integer)

   The parameter can be used to limit the number of contacts per
   AOR (Address of Record) in the user location database. Value 0
   disables the check.

   This is the default value and will be used only if no other
   value (for max_contacts) is passed as parameter to the save()
   function. That's it - the function parameter overwride this
   global parameter.

   Default value is 0.

   Example 1.10. Set max_contacts parameter
...
# Allow no more than 10 contacts per AOR
modparam("registrar", "max_contacts", 10)
...

1.3.11. retry_after (integer)

   The registrar can generate 5xx reply to REGISTER in various
   situations. It can, for example, happen when the max_contacts
   parameter is set and the processing of REGISTER request would
   exceed the limit. In this case the registrar would generate
   "503 Service Unavailable" response.

   If you want to add the Retry-After header field in 5xx replies,
   set this parameter to a value grater than zero (0 means do not
   add the header field). See section 20.33 of RFC3261 for more
   details.

   Default value is 0 (disabled).

   Example 1.11. Set retry_after parameter
...
modparam("registrar", "retry_after", 30)
...

1.3.12. sock_hdr_name (string)

   Header which contains a socket description (proto:IP:port) to
   override the received socket info. The header will be search
   and used only if the flag 's' (Socket header) is set at
   "save()" time.

   This makes sense only in multiple replicated servers scenarios.

   Default value is NULL.

   Example 1.12. Set sock_hdr_namer parameter
...
modparam("registrar", "sock_hdr_name", "Sock-Info")
...

1.3.13. mcontact_avp (string)

   AVP to store the modified binding/contact that is set during
   cached registrations scenario (when REGISTER is forwarded to
   another registrar). The AVP will be used to extract the
   "expires" value returned in the 200 OK by the main registrar.

   This makes sense only in cached registrations scenario, where
   your OpenSIPS is caching registrations before forwarding them
   to the main registrar.

   Default value is NULL.

   Example 1.13. Set mcontact_avp parameter
...
modparam("registrar", "mcontact_avp", "$avp(orig_ct)")
...
route {
   ...
   # before forwarding the REGISTER request, save the outgoing contact.
   # Be SURE to do it after all the possible changes over the contact,
   # like fix_nated_contact()
   $avp(orig_ct) = $ct.fields(uri);
   t_on_reply("do_save");
   t_relay("udp:ip:port");
   ...
}
...
onreply_route[do_save] {
        if ($rs=="200")
                save("location");
}
...

1.3.14. attr_avp (string)

   AVP to store specific additional information for each
   registration. This information is read from the AVP and stored
   (in memory, db or both) at every registrar 'save'. When a
   registrar 'lookup' or 'is_registered' function is called, the
   attr_avp is populated with the value saved at [re]registration.

   When doing call forking, the avp will hold multiple values. The
   position of the corresponding attribute information in attr_avp
   is equal to the branch index. An example scenario is given
   below.

   Default value is NULL.

   Example 1.14. Set attr_avp parameter
# reading attributes from the attr_pvar when doing parallel forking
...
modparam("registrar", "attr_avp", "$avp(attr)")

...
if (is_method("REGISTER")) {
        $avp(attr) = "contact_info";
        save("location");
        exit;
}
...
lookup("location");
t_on_branch("parallel_fork");
...
branch_route [parallel_fork] {
        xlog("Attributes for branch $T_branch_idx: $(avp(attr)[$T_branch
_idx])\n");
}


1.3.15. gruu_secret (string)

   The string that will be used in XORing when generating
   temporary GRUUs.

   If not set, 'OpenSIPS' is the default secret.

   Example 1.15. Set gruu_secret parameter
...
modparam("registrar", "gruu_secret", "top_secret")
...

1.3.16. disable_gruu (int)

   Globally disable GRUU handling

   Default value is 1 ( GRUU will not be handled ).

   Example 1.16. Set gruu_secret parameter
...
modparam("registrar", "disable_gruu", 0)
...

1.4. Exported Functions

1.4.1.  save(domain[, flags[, aor[, ownership_tag]]])

   The function processes a REGISTER message. It can add, remove
   or modify usrloc records depending on Contact and Expires HFs
   in the REGISTER message. On success, 200 OK will be returned
   listing all contacts that are currently in usrloc. On an error,
   error message will be send with a short description in reason
   phrase.

   Meaning of the parameters is as follows:
     * domain (static string) - Logical domain within registrar.
       If database is used then this must be name of the table
       which stores the contacts.
     * flags (string, optional) - string of the following flags:
          + 'm' (Memory only) - save the contacts only in memory
            cache without no DB operation;
          + 'r' (no Reply) - do not generate a SIP reply to the
            current REGISTER request.
          + 's' (Socket header) - look into REGISTER request for a
            header which contains a socket description
            (proto:IP:port). This socket info will be stored by
            register instead of the received socket info.
          + 'cnn' (max Contacts) - this flag can be used to limit
            the number of contacts for this AOR (Address of
            Record) in the user location database. Value 0
            disables the check. This parameter overrides the
            global "max_contacts" module parameter.
          + 'e(int)' (minimum expires) - this flag can be used to
            set minimum register expiration time. Values lower
            than this minimum will be automatically set to the
            minimum. Value 0 disables the checking. This parameter
            overrides the global min_expires module parameter.
          + 'E(int)' (maximum expires) - this flag can be used to
            set maximum register expiration time. Values higher
            than this maximum will be automatically set to the
            maximum. Value 0 disables the checking. This parameter
            overrides the global max_expires module parameter.
          + 'f' (force registration) - this flag can be used to
            force the registration of NEW contacts even if the
            maximum number of contacts is reached. In such a case,
            older contacts will be removed to make space to the
            new ones, without exceeding the maximum allowed
            number. This flag makes sense only if "cxx" is used.
          + 'p0' (Path support - 'off' mode) The Path header is
            saved into usrloc, but is never included in the reply.
          + 'p1' (Path support - lazy mode) The Path header is
            saved into usrloc, but is only included in the reply
            if path support is indicated in the registration
            request by the “path” option of the “Supported”
            header.
          + 'p2' (Path support - strict mode) The path header is
            only saved into usrloc, if path support is indicated
            in the registration request by the “path” option of
            the “Supported” header. If no path support is
            indicated, the request is rejected with “420 - Bad
            Extension” and the header “Unsupported: path” is
            included in the reply along with the received “Path”
            header. This mode is the one recommended by RFC-3327.
          + 'v' (path receiVed) if set, the “received” parameter
            of the first Path URI of a registration is set as
            received-uri and the NAT branch flag is set for this
            contact. This is useful if the registrar is placed
            behind a SIP loadbalancer, which passes the nat'ed UAC
            address as “received” parameter in it's Path uri.
       This parameter is a string composed of a set of flags.
     * aor (string, optional) - a custom AOR; if missing, the AOR
       will be taken from the default place - the TO header URI.
     * ownership_tag (string, optional) - a cluster-shared tag
       (see the clusterer module documentation for more details)
       which will be attached to each contact saved from the
       current request. This tag is only relevant in clustered
       user location scenarios and helps determine the current
       logical owner node of a contact. This, in turn, is useful
       in order to restrict nodes which are not currently
       responsible for this contact from performing certain
       actions (for example: incorrectly originating pings from a
       non-owned virtual IP address in highly-available setups).

   This function can be used from REQUEST_ROUTE and ONREPLY_ROUTE.

   If you plan to use the “save()” function in reply route, please
   refer to mcontact_avp module parameter.

   Example 1.17. save usage
...
# save into 'location', no flags, use default AOR (TO URI)
save("location");
...
# save into 'location', do not update DB, max 5 contacts per AOR,
# use default AOR (TO URI)
save("location","mc5");
...
# save into 'location', no flags, use as AOR the FROM URI
save("location","",$fu);
...
# save into 'location', no DB update, force registration, take AOR from
AVP
save("location","mr", $avp(aor));
...
# save into 'location', mark the contacts with the "vip" ownership tag a
nd
# replicate these contacts to the backup node, which does not currently
own "vip"
save("location", , , "vip");
...

1.4.2.  remove(domain, AOR[, [contact][, [next_hop][,
[sip_instance]]]])

   Explicitly remove contacts behind a given address-of-record.

   Meaning of the parameters is as follows:
     * domain (static string - Logical domain within the
       registrar. If a database is used, then this must be name of
       the table which stores the contacts.
     * AOR (string) - address-of-record to be searched (SIP URI)
     * contact (string, optional) - SIP URI filter for the contact
       to be removed. This must be the full SIP URI as used during
       registered.
     * next_hop (string, optional) - the next SIP IP
       address/hostname on the way back to this contact. See the
       section below for details on how the next hop is computed.
       Hostnames are resolved before matching.
     * sip_instance (string, optional) - a "+sip.instance" value
       to be used for filtering purposes.

   IMPORTANT: the IP address of each contact (for matching
   purposes) is computed as follows:
     * a. if a Path header is present, the hostname part of the
       Path URI will be resolved as the contact's IP address.
     * b. otherwise, if by using nathelper, the "Received" value
       (source IP of the next hop) is set for a contact, this
       becomes the chosen hostname to be resolved as the contact's
       IP address.
     * c. otherwise, the "hostname" part of the Contact header
       field URI is chosen to be resolved as the contact's IP
       address.

   This function can be used from REQUEST_ROUTE and ONREPLY_ROUTE.

   Example 1.18. remove usage
...
# remove all contacts belonging to the "bob" AOR
remove("location", "sip:bob@atlanta.com");
...
# remove only bob's home phone contact
remove("location", "sip:bob@atlanta.com", "sip:bob@46.50.64.78");
...
# remove all bob's phones which are behind "50.60.50.60"
# note that "contact" parameter has to be specified with NULL value even
 though not used
$var(next_hop) = "50.60.50.60"
remove("location", "sip:bob@atlanta.com", , $var(next_hop));
...
# remove bob's phone with contact "sip:bob@46.50.64.78" that is behind "
50.60.50.60"
remove("location", "sip:bob@atlanta.com", "sip:bob@46.50.64.78", "50.60.
50.60");
...
# remove all contacts behind bob's mobile device X
remove("location", "sip:bob@atlanta.com", , , "<urn:uuid:e5e68d40-f08a-4
600-b82e-ff4d5d8c1a8f>")

1.4.3.  lookup(domain [, flags [, aor]])

   The functions extracts username from Request-URI and tries to
   find all contacts for the username in usrloc. If there are no
   such contacts, -1 will be returned. If there are such contacts,
   Request-URI will be overwritten with the contact that has the
   highest q value and optionally the rest will be appended to the
   message (depending on append_branches parameter value).

   If the method_filtering option is enabled, the lookup function
   will return only the contacts that support the method of the
   processed request.

   Meaning of the parameters is as follows:
     * domain (static string) - Name of table that should be used
       for the lookup.
     * flags (string, optional)
          + 'b' (no Branches) - this flag controls how lookup
            function processes multiple contacts. If there are
            multiple contacts for the given username in usrloc and
            this flag is not set, Request-URI will be overwritten
            with the highest-q rated contact and the rest will be
            appended to sip_msg structure and can be later used by
            tm for forking. If the flag is set, only Request-URI
            will be overwritten with the highest-q rated contact
            and the rest will be left unprocessed.
          + 'B' (to Branches only) - this flags forces all found
            contacts to be uploaded only as branches (in the
            destination set) and not at all in the RURI of the
            current message. With this option, the lookup() can be
            also used in the context of a SIP reply.
          + 'r' (bRanch lookup) - this flag enables searching
            through existing branches for aor's and expanding them
            to contacts. For example, you have got AOR A in your
            ruri but you also want to forward your calls to AOR B.
            In order to do this, you must put AOR B in a branch,
            and if this flag enabled, the function will also
            expand AOR B to contacts, which will be put back into
            the branches. The AOR's that were in branches before
            the function call shall be removed.
            WARNING: if you want this flag activated, the 'b' (no
            Branches) flag must not be set, because by setting
            that flag you won't allow lookup to write in a branch.
          + 'm' (Method filtering) - setting this flag will enable
            contact filtering based on the supported methods
            listed in the "Allow" header field during
            registration. Contacts which did not present an
            "Allow" header field during registration are assumed
            to support all standard SIP methods.
          + 'u' (User-Agent filtering) - this flag enables regexp
            filtering by user-agent. It's useful with enabled
            append_branches parameter. Regexp must follow the 'u'
            flag and must use format like 'u/regexp/'.
          + 'i' (Case insensitive search) - this flag enables case
            insensitive filtering for the 'u' flag.
          + 'e' (Use extended regexp) - this flag enables using of
            extended regexp format for the 'u' flag.
          + 'g' (Global lookup) - this flag is only relevant with
            federated user location clustering. If set, the
            lookup() function will not only perform the classic
            in-memory "search-AoR-and-push-branches" operation,
            but will also perform a metadata lookup and append an
            additional branch for each returned result. The
            "in-memory branches" correspond to local contacts
            (current location), while the "metadata branches"
            correspond to contacts available on one or more of the
            remaining locations of the platform.
            The AoR metadata consists of the minimally required
            information in order for one of the VoIP platform's
            locations (data centers) to advertise the presence of
            a locally registered AoR for the global platform.
            Specifically, this consists of two pieces of
            information:
               o the AoR (e.g. "vladimir@federation-cluster")
               o the home IP (e.g. "10.0.0.223")
          + 'yXXXXX' (Max pinging latency) - maximally accepted
            contact pinging latency (microseconds). Contacts of an
            AoR with a higher latency will be discarded during the
            lookup.
          + 'Y' (Sort by pinging latency) - contacts will be
            picked in ascending order of their last successful
            pinging latency (fastest ping -> slowest ping). This
            flag may work together with the "y" flag.
     * AOR (string, optional) - AOR to lookup for; if missing, the
       RURI is used as AOR;

   Return codes:
     * 1 - contacts found and returned.
       -1 - no contact found.
       -2 - contacts found, but method not supported.
       -3 - internal error during processing.

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

   Example 1.19. lookup usage
...
lookup("location");  # simple lookup
   #or
lookup("location","m"); # lookup with method filtering
   #or
lookup("location","r"); #lookup with aor branch search;
                                                #all contacts except the
 first one shall be put
                                                #in the branches
   #or
lookup("location","u/phone/i"); # lookup with user-agent filtering
   #or
lookup("location","",$var(aor)); # simple lookup with AOR from var
switch ($retcode) {
    case -1:
    case -3:
        sl_send_reply(404, "Not Found");
        exit;
    case -2:
        sl_send_reply(405, "Not Found");
        exit;
};
...

1.4.4.  is_registered(domain ,[AOR])

   The function returns true if an AOR is registered, false
   otherwise. The function does not modify the message being
   process.

   NOTE: if called for a reply (from onreply_route), you must pass
   an AOR (as parameter), otherwise the function will fail.

   Meaning of the parameters is as follows:
     * domain (static string) - Name of table that should be used
       for the lookup.
     * AOR (string, optional) - AOR to lookup for; if missing, the
       source if the AOR is the "To" header for REGISTER request,
       "From" header for any other sip request.

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
   BRANCH_ROUTE, ONREPLY_ROUTE, LOCAL_ROUTE.

   Example 1.20. is_registered usage
...
/**/
if (is_method("REGISTER")) {
        /* automatically uses the URI from the To header */
        if (is_registered("location")) {
                xlog("this AOR is registered\n")
                ...
        }
};
/* check the From uri whether this aor is registered or not */
if (is_registered("location",$fu)) {
        xlog("caller is registered\n");
}
...

1.4.5.  is_contact_registered(domain ,[AOR],[contact],[callid])

   The function returns true if a contact and/or a callid from a
   certain AOR is registered, false otherwise. The function does
   not modify the message being process.

   Meaning of the parameters is as follows:
     * domain (static string) - Name of table that should be used
       for the lookup.
     * AOR (stirng, optional) - AOR to lookup for; if missing, the
       source if the AOR is the "To" header for REGISTER request,
       "From" header for any other sip request.
     * contact (stirng, optional) - callid to check if a contact
       if registered with this callid (this may help you to make
       distinction between newly registered contact (callid not
       registered so far) and re-registration (callid already
       registered).
     * callid (stirng, optional) - callid to check if a contact if
       registered with this callid (this may help you to make
       distinction between newly registered contact (callid not
       registered so far) and re-registration (callid already
       registered).

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
   BRANCH_ROUTE, ONREPLY_ROUTE, LOCAL_ROUTE.

   Example 1.21. is_contact_registered usage
...
/*let's say you want to block users that are not registered*/
if (is_method("INVITE")) {
        if (!is_contact_registered("location")) {
                sl_send_reply(401, "Unauthorized");
        ...
        }
}
/* you want to check the second contact from the message whether it is
registered or not */
if(is_method("INVITE")) {
        if (is_contact_registered("location",$fu,$(ct[1]),))
                xlog("caller is registered\n");
}
...

1.4.6.  is_ip_registered(domain ,[AOR],IPvar)

   The function returns true if there is at least one contact that
   has been registered from the IP in the IPvar variable. The IP
   is matched against the received host, if it exists, or the
   contact host otherwise. This function does not modify the
   message being process. This function replaces the old
   "is_other_contact" function.

   Meaning of the parameters is as follows:
     * domain (static string) - Name of table that should be used
       for the lookup.
     * AOR (stirng, optional) - AOR to lookup for; if missing, the
       source if the AOR is the "To" header for REGISTER request,
       "From" header for any other sip request.
     * IPvar (var) - the variable containing the IP matched
       against the contact host or the received host (see above).
       If the IPvar is an AVP containing multiple values/IPs, then
       all the values are checked.

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
   BRANCH_ROUTE, ONREPLY_ROUTE, LOCAL_ROUTE.

   Example 1.22. is_ip_registered usage
...
/* check the source ip  whether it is already registered */
if (is_method("REGISTER")) {
        if (is_ip_registered("location",$tu,$si)) {
                xlog("already registered from this ip\n");
                ...
        }
};
...

1.4.7.  add_sock_hdr(hdr_name)

   Adds to the current REGISTER request a new header with
   “hdr_name” which contains the description of the received
   socket (proto:ip:port)

   This makes sense only in multiple replicated servers scenarios.

   Meaning of the parameters is as follows:
     * hdr_name (string) - header name to be used.

   This function can be used from REQUEST_ROUTE.

   Example 1.23. add_sock_hdr usage
...
add_sock_hdr("Sock-Info");
...

1.5. Exported Statistics

1.5.1. max_expires

   Value of max_expires parameter.

1.5.2. max_contacts

   The value of max_contacts parameter.

1.5.3. defaults_expires

   The value of default_expires parameter.

1.5.4. accepted_regs

   Number of accepted registrations.

1.5.5. rejected_regs

   Number of rejected registrations.

Chapter 2. Frequently Asked Questions

   2.1.

   What happened with the old “append_branch” module parameter?

   It was removed as global option, as the “lookup” function takes
   this option via the flag "b" (append Branches) See the
   documentation of the “lookup” function.

   2.2.

   What happened with the old “method_filtering” module parameter?

   It was removed as global option, as the “lookup” function takes
   this option via the flag "m" (Method filtering) See the
   documentation of the “lookup” function.

   2.3.

   What happened with the old “sock_flag” module parameter?

   It was removed as global option, as the “save” function takes
   this option via the flag "s" (Socket header) See the
   documentation of the “save” function.

   2.4.

   What happened with the old “use_path” and “path_mode” module
   parameters?

   They were removed as global option, as the “save” function
   takes these options via the flag "px" (path support) See the
   documentation of the “save” function.

   2.5.

   What happened with the old “path_use_received” module
   parameter?

   It was removed as global option, as the “save” function takes
   this option via the flag "v" (path receiVed) See the
   documentation of the “save” function.

   2.6.

   What happened with the old “nat_flag” module parameter?

   It was removed, as the module internally loads this value from
   the “USRLOC” module (see the “nat_bflag” USRLOC parameter).

   2.7.

   What happened with the old “use_domain” module parameter?

   It was removed, as the module internally loads this option from
   the “USRLOC” module. This was done in order to simplify the
   configuration.

   2.8.

   What happened with the old “save_noreply” and “save_memory”
   functions?

   There functions were merged into the new “save(domain,flags)”
   functions. If a reply should be sent or if the DB should be
   updated also is controlled via the flags.

   2.9.

   Where can I find more about OpenSIPS?

   Take a look at http://www.opensips.org/.

   2.10.

   Where can I post a question about this module?

   First at all check if your question was already answered on one
   of our mailing lists:
     * User Mailing List -
       http://lists.opensips.org/cgi-bin/mailman/listinfo/users
     * Developer Mailing List -
       http://lists.opensips.org/cgi-bin/mailman/listinfo/devel

   E-mails regarding any stable OpenSIPS release should be sent to
   <users@lists.opensips.org> and e-mails regarding development
   versions should be sent to <devel@lists.opensips.org>.

   If you want to keep the mail private, send it to
   <users@lists.opensips.org>.

   2.11.

   How can I report a bug?

   Please follow the guidelines provided at:
   https://github.com/OpenSIPS/opensips/issues.

   2.12.

   What happened to the desc_time_order parameter?

   It was removed, as its functionality was mmigrate into usrloc
   module, were there is a parameter with the same name.

Chapter 3. Contributors

3.1. By Commit Statistics

   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) 160 106 2328 1952
   2. Jan Janak (@janakj) 121 73 3465 1102
   3. Liviu Chircu (@liviuchircu) 93 53 1499 1524
   4. Daniel-Constantin Mierla (@miconda) 23 19 160 105
   5. Razvan Crainea (@razvancrainea) 16 11 262 72
   6. Vlad Paiu (@vladpaiu) 16 10 489 81
   7. Jiri Kuthan (@jiriatipteldotorg) 15 9 538 45
   8. Ionut Ionita (@ionutrazvanionita) 15 4 763 248
   9. Andreas Granig 13 7 527 36
   10. Vlad Patrascu (@rvlad-patrascu) 13 4 163 373

   All remaining contributors: Henning Westerholt (@henningw),
   Andrei Pelinescu-Onciul, Ovidiu Sas (@ovidiusas), Juha Heinanen
   (@juha-h), Nick Altmann (@nikbyte), Ancuta Onofrei,
   Elena-Ramona Modroiu, Maksym Sobolyev (@sobomax), Dan Pascu
   (@danpascu), Sergio Gutierrez, Carsten Bock, Jeffrey Magder,
   Kobi Eshun (@ekobi), Marcus Hunger, Julián Moreno Patiño, Phil
   D'Amore, Klaus Darilion, Irina-Maria Stanescu, Dmitry Semyonov,
   Konstantin Bokarius, Jesus Rodrigues, Dusan Klinec, Peter
   Lemenkov (@lemenkov), Ruslan Bukin, Saúl Ibarra Corretgé
   (@saghul), @jalung, Tolga Tarhan, Edson Gellert Schubert.

   (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

3.2. By Commit Activity

   Table 3.2. Most recently active contributors^(1) to this module
                      Name                   Commit Activity
   1.  Vlad Patrascu (@rvlad-patrascu)     May 2017 - Apr 2019
   2.  Bogdan-Andrei Iancu (@bogdan-iancu) Sep 2003 - Apr 2019
   3.  Liviu Chircu (@liviuchircu)         Mar 2013 - Mar 2019
   4.  Razvan Crainea (@razvancrainea)     Apr 2011 - Nov 2018
   5.  Peter Lemenkov (@lemenkov)          Jun 2018 - Jun 2018
   6.  @jalung                             Aug 2017 - Aug 2017
   7.  Ovidiu Sas (@ovidiusas)             May 2011 - Mar 2017
   8.  Ionut Ionita (@ionutrazvanionita)   Jul 2015 - Feb 2017
   9.  Julián Moreno Patiño                Feb 2016 - Feb 2016
   10. Dusan Klinec                        Dec 2015 - Dec 2015

   All remaining contributors: Nick Altmann (@nikbyte), Vlad Paiu
   (@vladpaiu), Tolga Tarhan, Saúl Ibarra Corretgé (@saghul),
   Ruslan Bukin, Irina-Maria Stanescu, Kobi Eshun (@ekobi), Phil
   D'Amore, Sergio Gutierrez, Klaus Darilion, Henning Westerholt
   (@henningw), Daniel-Constantin Mierla (@miconda), Konstantin
   Bokarius, Edson Gellert Schubert, Jesus Rodrigues, Dan Pascu
   (@danpascu), Ancuta Onofrei, Marcus Hunger, Juha Heinanen
   (@juha-h), Elena-Ramona Modroiu, Jeffrey Magder, Carsten Bock,
   Andreas Granig, Dmitry Semyonov, Maksym Sobolyev (@sobomax),
   Jan Janak (@janakj), Andrei Pelinescu-Onciul, Jiri Kuthan
   (@jiriatipteldotorg).

   (1) including any documentation-related commits, excluding
   merge commits

Chapter 4. Documentation

4.1. Contributors

   Last edited by: Vlad Patrascu (@rvlad-patrascu), Liviu Chircu
   (@liviuchircu), Bogdan-Andrei Iancu (@bogdan-iancu), Peter
   Lemenkov (@lemenkov), Razvan Crainea (@razvancrainea), Ionut
   Ionita (@ionutrazvanionita), Julián Moreno Patiño, Nick Altmann
   (@nikbyte), Vlad Paiu (@vladpaiu), Ovidiu Sas (@ovidiusas),
   Irina-Maria Stanescu, Kobi Eshun (@ekobi), Sergio Gutierrez,
   Klaus Darilion, Daniel-Constantin Mierla (@miconda), Konstantin
   Bokarius, Edson Gellert Schubert, Jesus Rodrigues, Marcus
   Hunger, Juha Heinanen (@juha-h), Elena-Ramona Modroiu, Carsten
   Bock, Andreas Granig, Jan Janak (@janakj).

   Documentation Copyrights:

   Copyright © 2003 FhG FOKUS
