# &adminguide;

## Overview

This module implements various functions and checks related to SIP message handling and URI handling.

This module also provides a function to answer OPTIONS requests which are directed to the server itself. This means an OPTIONS request which has the address of the server in the request URI, and no username in the URI. The request will be answered with a 200 OK with the capabilities of the server.

To answer OPTIONS request directed to your server is the easiest way for is-alive-tests on the SIP (application) layer from remote (similar to ICMP echo requests, also known as ping, on the network layer).

## Dependencies

### &kamailio; Modules

The following modules must be loaded before this module:

- sl -- Stateless replies.

### External Libraries or Applications

The following libraries or applications must be installed before running &kamailio; with this module loaded:

- None.

## Parameters

### `options_accept` (string)

This parameter is the content of the Accept header field. Note: it is not clearly written in RFC3261 if a proxy should accept any content (the default */*) because it does not care about content. Or if it does not accept any content, which is .

Default value is */*.

#### Set `options_accept` parameter

    ...
    modparam("siputils", "options_accept", "application/*")
    ...

### `options_accept_encoding` (string)

This parameter is the content of the Accept-Encoding header field. Please do not change the default value because &kamailio; does not support any encodings yet.

Default value is .

#### Set `options_accept_encoding` parameter

    ...
    modparam("siputils", "options_accept_encoding", "gzip")
    ...

### `contact_flds_separator` (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 `contact_flds_separator` parameter

    ...
    modparam("siputils", "contact_flds_separator", "-")
    ...

then an encoded uri might look sip:user-password-ip-port-protocol@PublicIP

### `options_accept_language` (string)

This parameter is the content of the Accept-Language header field. You can set any language code which you prefer for error descriptions from other devices, but presumably there are not many devices around which support other languages than the default English.

Default value is en.

#### Set `options_accept_language` parameter

    ...
    modparam("siputils", "options_accept_language", "de")
    ...

### `options_support` (string)

This parameter is the content of the Support header field, indicating SIP extensions. Please do not change the default value, because &kamailio; currently does not support any of the SIP extensions registered at the IANA.

Default value is .

#### Set `options_support` parameter

    ...
    modparam("siputils", "options_support", "100rel")
    ...

### `rpid_prefix` (string)

Prefix to be added to Remote-Party-ID header field just before the URI returned from either radius or database.

Default value is .

#### rpid_prefix parameter example

    modparam("siputils", "rpid_prefix", "Whatever <")

### `rpid_suffix` (string)

Suffix to be added to Remote-Party-ID header field after the URI returned from either radius or database.

Default value is ;party=calling;id-type=subscriber;screen=yes.

#### rpid_suffix parameter example

    modparam("siputils", "rpid_suffix", "@1.2.3.4>")

### `rpid_avp` (string)

Full AVP specification for the AVP which stores the RPID value. It used to transport the RPID value from authentication backend modules (auth_db or auth_radius) or from script to the auth function append_rpid_hf and is_rpid_user_e164.

If defined to NULL string, all RPID functions will fail at runtime.

Default value is $avp(s:rpid).

#### rpid_avp parameter example

    modparam("siputils", "rpid_avp", "$avp(myrpid)")

### `e164_max_len` (int)

The maximum length for checking e164 numbers, including the leading '+'.

Default value is 16.

#### e164_max_len parameter example

    modparam("siputils", "e164_max_len", 20)

## Functions

### `options_reply()`

This function checks if the request method is OPTIONS and if the request URI does not contain a username. If both are true the request will be answered stateless with 200 OK and the capabilities from the modules parameters.

It sends 500 Server Internal Error for some errors and returns false if it is called for a wrong request.

The check for the request method and the missing username is optional because it is also done by the function itself. But you should not call this function outside the myself check because in this case the function could answer OPTIONS requests which are sent to you as outbound proxy but with another destination than your proxy (this check is currently missing in the function).

This function can be used from REQUEST_ROUTE.

#### `options_reply` usage

    ...
    if (uri==myself) {
    	if ((method==OPTIONS) && (! uri=~"sip:.*[@]+.*")) {
    		options_reply();
    	}
    }
    ...

### `is_user(username)`

Check if the username in credentials matches the given username.

Meaning of the parameters is as follows:

- username - Username string.

This function can be used from REQUEST_ROUTE.

#### `is_user` usage

    ...
    if (is_user("john")) {
    	...
    };
    ...

### `has_totag()`

Check if To header field uri contains tag parameter.

This function can be used from ANY_ROUTE.

#### `has_totag` usage

    ...
    if (has_totag()) {
    	...
    };
    ...

### `uri_param(param)`

Find if Request URI has a given parameter with no value

Meaning of the parameters is as follows:

- param - parameter name to look for.

This function can be used from REQUEST_ROUTE.

#### `uri_param` usage

    ...
    if (uri_param("param1")) {
    	...
    };
    ...

### `uri_param(param, value)`

Find if Request URI has a given parameter with matching value

Meaning of the parameters is as follows:

- param - parameter name to look for.

- value - parameter value to match.

This function can be used from REQUEST_ROUTE.

#### `uri_param` usage

    ...
    if (uri_param("param1","value1")) {
    	...
    };
    ...

### `uri_param_any(param)`

Find if Request URI has a given parameter with or without value.

Meaning of the parameters is as follows:

- param - parameter name to look for.

This function can be used from REQUEST_ROUTE.

#### `uri_param_any` usage

    ...
    if (uri_param_any("param1")) {
    	...
    }
    ...

### `add_uri_param(param)`

Add to RURI a parameter (name=value);

Meaning of the parameters is as follows:

- param - parameter to be appended in name=value format.

This function can be used from REQUEST_ROUTE.

#### `add_uri_param` usage

    ...
    add_uri_param("nat=yes");
    ...

### `get_uri_param(name, var)`

Get the value of RURI parameter.

Meaning of the parameters is as follows:

- name - the name of R-URI parameter

- var - the variable where to store the value of the parameter

This function can be used from REQUEST_ROUTE.

#### `add_uri_param` usage

    ...
    get_uri_param("nat", "$var(nat)");
    ...

### `uri_param_rm(param)`

Remove parameter from Request URI.

Meaning of the parameters is as follows:

- param - parameter name.

This function can be used from REQUEST_ROUTE.

#### `uri_param_rm` usage

    ...
    if (uri_param_rm("param1")) {
    	...
    }
    ...

### `tel2sip(uri, hostpart, result)`

Converts URI in first param (pseudo variable or string) to SIP URI, if it is a tel URI. If conversion was done, writes resulting SIP URI to third param (pseudo variable). Returns 1 if conversion succeeded, 2 if no conversion was needed, and -1 in case of error.

The conversion follows the rules in RFC 3261 section 19.1.6:

- Visual separators ( "-", ".", "(", ")" ) are removed from tel URI number before converting it to SIP URI userinfo.

- tel URI parameters are downcased before appending them to SIP URI userinfo

The SIP URI hostpart is taken from second param (pseudo variable or string).

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

#### `tel2sip` usage

    ...
    # $ru: tel:+(34)-999-888-777
    # $fu: sip:test@foo.com
    tel2sip("$ru", $fd", "$ru");
    # $ru:  sip:+34999888777@foo.com;user=phone

    # $ru: tel:+12-(34)-56-78;Ext=200;ISUB=+123-456
    # $fu: sip:test@foo.com
    tel2sip("$ru", $fd", "$ru");
    # $ru:  sip:+12345678;ext=200;isub=+123-456@foo.com;user=phone
    ...

### `tel2sip2(uri, hostpart, result)`

Alternative to sip2tel() function that tries to follow closer the RFC requrements (e.g., sort tel: uri parameters copied to the sip: uri in the manner defined in the standard; deletes the phone-context parameter if it is a domain, and, takes visual separators from the phone-context parameter if it is a telephone number).

Its parameters have the same meaning as for tel2sip().

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

#### `tel2sip2` usage

    ...
    # $ru: tel:+(34)-999-888-777
    # $fu: sip:test@foo.com
    tel2sip2("$ru", $fd", "$ru");
    # $ru:  sip:+34999888777@foo.com;user=phone
    ...

### `is_e164(pseudo-variable)`

Checks if string value of pseudo variable argument is an E164 number.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, and LOCAL_ROUTE.

#### `is_e164` usage

    ...
    if (is_e164("$fU")) {  # Check From header URI user part
       ...
    }
    if (is_e164("$avp(i:705)") {
       # Check stgring value stored in avp i:705
       ...
    };
    ...

### `is_uri_user_e164(pseudo-variable)`

Checks if userpart of URI stored in pseudo variable is E164 number.

This function can be used from ANY_ROUTE.

#### `is_uri_user_e164` usage

    ...
    if (is_uri_user_e164("$fu")) {  # Check From header URI user part
       ...
    }
    if (is_uri_user_e164("$avp(i:705)") {
       # Check user part of URI stored in avp i:705
       ...
    };
    ...

### `is_uri(pseudo-variable)`

Checks if string value of pseudo variable argument is a valid uri.

This function can be used from ANY_ROUTE.

#### `is_uri` usage

    ...
    if (is_uri("$var(x)")) {  # Check if variable contains a uri
       ...
    }
    if (is_uri("$avp(i:705)") {
       # Check value stored in avp i:705
       ...
    };
    ...

### `is_tel_number(tval)`

Checks if the parameter value is a telephone number: starting with one optional +, followed by digits. The parameter can include variables.

This function can be used from ANY_ROUTE.

#### `is_tel_number` usage

    ...
    if (is_tel_number("$rU")) {  # Test if R-URI user is telephone number
       ...
    }
    if (is_tel_number("+24242424")) {
       ...
    }
    ...

### `is_numeric(tval)`

Checks if the parameter value consists solely of decimal digits. The parameter can include variables.

This function can be used from ANY_ROUTE.

#### `is_numeric` usage

    ...
    if (is_numeric("$rU")) {  # Test if R-URI user consists of decimal digits
       ...
    }
    ...

### `is_alphanum(tval)`

Checks if the parameter value consists solely of decimal digits or alphabetic ASCII characters. The parameter can include variables.

This function can be used from ANY_ROUTE.

#### `is_alphanum` usage

    ...
    if (is_alphanum("$rU")) {
       ...
    }
    ...

### `is_alphanumex(tval, eset)`

Checks if the value of parameter 'tval' consists solely of decimal digits, alphabetic ASCII characters and the characters in the second parameter 'eset'. The parameters can include variables.

This function can be used from ANY_ROUTE.

#### `is_alphanumex` usage

    ...
    if (is_alphanumex("$rU", "+.-_")) {
       ...
    }
    ...

### `encode_contact(encoding_prefix, hostpart)`

This function will encode uri-s inside Contact header in the following manner sip:username:password@ip:port;transport=protocol goes sip:encoding_prefix*username*password*ip*port*protocol@hostpart.

* is the default separator and can be changed by setting the contact_flds_separator module parameter.

Note: This function discards all of the URI parameters. Thus, none of the parameters (except the transport parameter which is encoded into the userpart) can be restored.

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.

- hostpart - An IP address or a hostname.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

#### `encode_contact` usage

    ...
    if (src_ip == 10.0.0.0/8) encode_contact("natted_client","1.2.3.4");
    ...

### `decode_contact()`

This function will decode the request URI. If the RURI is in the format sip:encoding_prefix*username*password*ip*port*protocol@hostpart it will be decoded 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:

This function can be used from REQUEST_ROUTE.

#### `decode_contact` usage

    ...
    if (uri =~ "^sip:natted_client") { decode_contact(); }
    ...

### `decode_contact_header()`

This function will decode &uri;s inside Contact header. If the URI in the format sip:encoding_prefix*username*ip*port*protocol@hostpart it will be decoded 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:

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

#### `decode_contact_header` usage

    ...
    reply_route[2] {
    	...
    	decode_contact_header();
    	...
    }
    ...

### `cmp_uri(str1, str2)`

The function returns true if the two parameters matches as SIP URI.

This function can be used from ANY_ROUTE.

#### `cmp_uri` usage

    ...
    if(cmp_uri("$ru", "sip:kamailio@kamailio.org"))
    {
        # do interesting stuff here
    }
    ...

### `cmp_aor(str1, str2)`

The function returns true if the two parameters matches as AoR. The parameters have to be SIP URIs.

This function can be used from ANY_ROUTE.

#### `cmp_aor` usage

    ...
    if(cmp_aor("$rU@KaMaIlIo.org", "sip:kamailio@$fd"))
    {
        # do interesting stuff here
    }
    ...

### `cmp_hdr_name(str1, str2)`

The function returns true (return code 1) if the two parameters matches as header names.

This function can be used from ANY_ROUTE.

#### `cmp_hdr_name` usage

    ...
    if(cmp_hdr_name("$var(hname)", "From"))
    {
        # do interesting stuff here
    }
    ...

### `append_rpid_hf()`

Appends to the message a Remote-Party-ID header that contains header 'Remote-Party-ID: ' followed by the saved value of the SIP URI received from the database or radius server followed by the value of module parameter radius_rpid_suffix. The function does nothing if no saved SIP URI exists.

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

#### append_rpid_hf usage

    ...
    append_rpid_hf();  # Append Remote-Party-ID header field
    ...

### `append_rpid_hf(prefix, suffix)`

This function is the same as . The only difference is that it accepts two parameters--prefix and suffix to be added to Remote-Party-ID header field. This function ignores rpid_prefix and rpid_suffix parameters, instead of that allows to set them in every call.

Meaning of the parameters is as follows:

- prefix - Prefix of the Remote-Party-ID URI. The string will be added at the beginning of the body of the header field, just before the URI.

- suffix - Suffix of the Remote-Party-ID header field. The string will be appended at the end of the header field. It can be used to set various URI parameters, for example.

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

#### append_rpid_hf(prefix, suffix) usage

    ...
    # Append Remote-Party-ID header field
    append_rpid_hf("", ";party=calling;id-type=subscriber;screen=yes");
    ...

### `is_rpid_user_e164()`

The function checks if the SIP URI received from the database or radius server and will potentially be used in Remote-Party-ID header field contains an E164 number (+followed by up to 15 decimal digits) in its user part. Check fails, if no such SIP URI exists (i.e. radius server or database didn't provide this information).

This function can be used from REQUEST_ROUTE.

#### is_rpid_user_e164 usage

    ...
    if (is_rpid_user_e164()) {
        # do something here
    };
    ...

### `set_uri_user(uri, user)`

Sets userpart of SIP URI stored in writable pseudo variable 'uri' to value of pseudo variable 'user'.

This function can be used from ANY_ROUTE.

#### set_uri_user usage

    ...
    $var(uri) = "sip:user@host";
    $var(user) = "new_user";
    set_uri_user("$var(uri)", "$var(user)");
    ...

### `set_uri_host(uri, host)`

Sets hostpart of SIP URI stored in writable pseudo variable 'uri' to value of pseudo variable 'host'.

This function can be used from ANY_ROUTE.

#### set_uri_host usage

    ...
    $var(uri) = "sip:user@host";
    $var(host) = "new_host";
    set_uri_host("$var(uri)", "$var(host)");
    ...

### `is_request()`

Return true if the SIP message is a request.

This function can be used from ANY_ROUTE.

#### `is_request` usage

    ...
    if (is_request()) {
    	...
    }
    ...

### `is_reply()`

Return true if the SIP message is a reply.

This function can be used from ANY_ROUTE.

#### `is_reply` usage

    ...
    if (is_reply()) {
    	...
    }
    ...

### `is_sip()`

Return true if it is a SIP message.

This function can be used from ANY_ROUTE.

#### `is_sip` usage

    ...
    if (is_sip()) {
    	...
    }
    ...

### `is_http()`

Return true if it is a HTTP message.

This function can be used from ANY_ROUTE.

#### `is_http` usage

    ...
    if (is_http()) {
    	...
    }
    ...

### `is_gruu([uri])`

The function returns true if the uri is GRUU ('gr' parameter is present): 1 - pub-gruu; 2 - temp-gruu.

Meaning of the parameters is as follows:

- uri - the SIP URI to check for GRUU parameter. It is optional, when missing, the value of R-URI is used.

This function can be used from ANY_ROUTE.

#### is_gruu() usage

    ...
    if(is_gruu()) { ... }
    ...

### `is_supported(option)`

Function returns true if given option is listed in Supported header(s) (if any) of the request. Currently the following options are known: path, 100rel, timer, eventlist, gruu, and outbound.

This function can be used from ANY_ROUTE.

#### is_supported() usage

    ...
    if (is_supported("outbound")) { ... }
    ...

### `is_first_hop([mode])`

The function returns true if the proxy is first hop after the original sender based on a best effort estimation by checking Via and Record-Route headers.

For incoming SIP requests, it means there is only one Via header.

For incoming SIP replies, if mode==0, it means that top Record-Route URI is 'myself' and source address is not matching local IP (to avoid detecting in case of local loops). Therefore for mode==0 the detection is done only when Record-Route has an IP address in its URI (for a domain, it returns -1/false). If mode==1, then the check of local IP is no longer done, only if top Record-Route is myself, returning true also if there is a domain, assuming that is expected no looping can happen based on config rules.

Note that it does not detect spirals, which can have the condition for replies true also in the case of additional SIP reply reception.

Parameter mode is optional and can be an integer or a variable holding an integer. If not provided, the behaviour is like mode==0.

This function can be used from ANY_ROUTE.

#### is_first_hop() usage

    ...
    if(is_first_hop()) { ... }
    ...
    if(is_first_hop("1")) { ... }
    ...

### `sip_p_charging_vector(flags)`

Manage the P-Charging-Vector header (RFC7315). The flags can be: 'r' - remove; 'g' - generate; 'f' - force (remove + generate). Once a new PCV has been generated by 'g' or 'f' the PCV cannot be changed again. The icid-generated-at parameter of a generated PCV will be set to the sending interface.IP address.

Return Codes:

- 1 - Nothing was done.

- (2 - intentionally left out)

- 3 - P-Charging-Vector header has been newly generated.

- 4 - P-Charging-Vector header has been deleted.

- 5 - P-Charging-Vector header has been replaced or inserted after deletion.

- negative - Any error occured during execution.

This function can be used from ANY_ROUTE.

#### sip_p_charging_vector() usage

    ...
    sip_p_charging_vector("g");
    ...

### `contact_param_encode(pname, saddr)`

This function encodes URI inside Contact headers by building a new URI from 'saddr' parameter and adding a parameter with the name 'pname' containing incoming URI encoded in Base64URL format.

Meaning of the parameters is as follows:

- pname - name of the new URI parameter to hold the encoded incoming URI.

- saddr - local server address in SIP URI format.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

#### `contact_param_encode` usage

    ...
    if (is_method("REGISTER") and src_ip == 10.0.0.0/8) {
        contact_param_encode("ksu", "sip:1.2.3.4:5060;transport=tcp");
    }
    ...

### `contact_param_encode_alias(pname, saddr)`

Similar to contact_param_encode() but it also adds the alias parameter with the encoded source address to the original Contact URI.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

#### `contact_param_encode_alias` usage

    ...
    if (is_method("SUBSCRIBE") and src_ip == 10.0.0.0/8) {
        contact_param_encode_alias("ksu", "sip:1.2.3.4:5060;transport=tcp");
    }
    ...

### `contact_param_decode(pname)`

This function decodes URI inside Contact headers by building a new URI from 'pname' parameter, decoding its value from Base64URL.

Meaning of the parameters is as follows:

- pname - name of the incoming URI parameter holding the encoded URI value.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

#### `contact_param_decode` usage

    ...
    if (is_method("REGISTER") and src_ip == 1.2.3.4) {
        contact_param_decode("ksu");
    }
    ...

### `contact_param_decode_uri(pname)`

This function decodes R-URI (request URI) by building a new R-URI from 'pname' parameter, decoding its value from Base64URL.

Meaning of the parameters is as follows:

- pname - name of the incoming URI parameter holding the encoded URI value.

This function can be used from REQUEST_ROUTE.

#### `contact_param_decode_ruri` usage

    ...
    if (is_method("INVITE") and src_ip == 1.2.3.4) {
        contact_param_decode_ruri("ksu");
    }
    ...

### `contact_param_rm(pname)`

This function removes the parameter from the URIs inside the Contact headers.

Meaning of the parameters is as follows:

- pname - name of the URI parameter.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

#### `contact_param_rm` usage

    ...
    if (is_method("REGISTER") and src_ip == 1.2.3.4) {
        contact_param_rm("myparam");
    }
    ...

### `contact_param_check(pname)`

This function returns true (1) if the URI inside the Contact header contains the parameter with the name 'pname'. Otherwise it returns false (-1).

Meaning of the parameters is as follows:

- pname - name of the URI parameter.

This function can be used from ANY_ROUTE.

#### `contact_param_check` usage

    ...
    if (contact_param_check("myparam")) {
    }
    ...

### `hdr_date_check(tdiff)`

Returns true if sip message has Date header and its value is lower than 'NOW() - tdiff'.

Meaning of the parameters is as follows:

- tdiff - time difference in seconds, it can be a variable or static integer value.

This function can be used from ANY_ROUTE.

#### `hdr_date_check` usage

    ...
    if (!hdr_date_check("10")) {
        sl_send_reply("403", "Outdated date");
        exit;
    }
    ...

### `sip_parse_headers()`

Return true if parsing (fast mode) all SIP headers is successful.

This function can be used from ANY_ROUTE.

#### `sip_parse_headers` usage

    ...
    if (sip_parse_headers()) {
    	...
    }
    ...

## Exported pseudo-variables

### `$pcv(all)`

full P-Charging-Vector header

### `$pcv(value)`

icid-value field (see RFC7315 section 5.6)

### `$pcv(genaddr)`

icid-generated-at field (see RFC7315 section 5.6)

### `$pcv(orig)`

orig-ioi field (see RFC7315 section 5.6)

### `$pcv(term)`

term-ioi field (see RFC7315 section 5.6)

### `$pcv(status)`

Returns whether the PCV header was successfully parsed, deleted, newly generated or other.

- 0 - No P-Charging-Vector header in message.

- 1 - P-Charging-Vector header in message and parsed successfully.

- 2 - P-Charging-Vector is present, but has no valid icid-value parameter.

- 3 - P-Charging-Vector header has been newly generated or replaced.

- 4 - P-Charging-Vector header has been deleted.

Negative values indicate an internal error during the parsing process.