Kamailio SIP Server v4.3.x (stable): Pseudo-Variables

The term “pseudo-variable” is used for special tokens that can be given as parameters to different script functions and they will be replaced with a value before the execution of the function.

The beginning of a “pseudo-variable” is marked by the character “$”. If you want to have the character “$” just double it “$$”.

There is a set of predefined pseudo-variables, which have the name composed from one or more characters, and special pseudo-variables that are references to dynamic fields (AVP and Headers).

Pseudo-Variables are implemented by various modules, most of them are provided by pv (if there is no special reference to a module, expect that the pseudo-variable is provided by pv module).

Pseudo-variables can be used with many modules, among them:

• acc
• avpops
• htable
• textops
• uac
• xlog

Predefined pseudo-variables are listed in alphabetical order.

$$ - represents the character '$'

$_s(format) - returns the string after evaluating all pseudo-variables in format

    $var(x) = "sip:" + $rU + "@" + $fd;

    # is equivalent of:

    $var(x) = $_s(sip:$rU@$fd);

$ai - reference to URI in request's P-Asserted-Identity header (see RFC 3325)

$adu - URI from Authorization or Proxy-Authorization header. This URI is used when calculating the HTTP Digest Response.

$aa - algorithm from Authorization or Proxy-Authorization header.

$ar - realm from Authorization or Proxy-Authorization header

$au - user part of username from Authorization or Proxy-Authorization header

$ad - domain part of username from Authorization or Proxy-Authorization header

$aU - whole username from Authorization or Proxy-Authorization header

$Au - username for accounting purposes. It's a selective pseudo variable (inherited from acc module). It returns $au if exits or From username otherwise.

$branch(name) - reference to attribute 'name' of a branch

This pseudo variable gives you access to the “additional branches” only, not to the “main branch”. E.g. if there are 3 clients registered for the same AoR, after lookup() you will have one contact in the “main branch” and two “additional branches”. Using $branch() you can access the additional branches, the main branch can be accessed using $ru and $du. (Note: In branch_routes there is no distinction between the main and the additional branches - the branch_route will be called once for each one of them.)

The 'name' can be:

• uri - return uri of the branch
• dst_uri - return destination uri (next hop address)
• path - return the path vector for the branch
• q - return the q value of the branch
• send_socket - return the socket to be used to send the branch
• count - return the number of the branches
• flags - return the branch flags value
• ruid - return the ruid of the branch (Record internal Unique ID from usrloc)

The PV can take an index to access a specif branch: $(branch(name)[index])

Example:

$var(i)=0;
while($var(i)<$branch(count))
{
   xlog("$(branch(uri)[$var(i)])\n");
   $var(i) = $var(i) + 1;
}

Starting with 3.1.0, you can assign value per attribute. Index can be used to update a specific branch:

$(branch(attr)[index]) = value;

If index is missing, first branch is used. If index is -1 the last branch is used.

Assigning $null to uri attribute will drop the branch, for the rest of attributes will just set the value to null.

$(branch(uri)[2]) = "sip:test@kamailio.org;transport=sctp";

$br - reference to request's first branch

It is R/W variable, you can assign values to it directly in configuration file (will add a new branch).

$bR - reference to request's all branches

$bf - reference to branch flags of branch 0 (RURI) - decimal output

It is R/W variable (you can assign values to it directly in configuration file)

$bF - reference to branch flags of branch 0 (RURI) - hexa output

It is R/W variable (you can assign values to it directly in configuration file)

$bs - body size

$ci - reference to body of call-id header (R/O)

$cl - reference to body of content-length header

$cnt(avp) - return the number of avps

xlog("$$avp(x) fount $cnt($avp(x)) times\n");

$conid - The TCP connection ID of the connection the current message arrived on for TCP, TLS, WS, and WSS. Set to $null for SCTP and UDP.

$cs - reference to the sequence number in the cseq header. The method in the CSeq header is identical to the request method, thus use $rm to get the method (works also for responses).

$ct - reference to body of contact header

$cT - reference to body of content-type header

$dd - reference to domain of destination uri (without port)

$di - reference to Diversion header URI

$dip - reference to Diversion header “privacy” parameter value

$dir - reference to Diversion header “reason” parameter value

$dic - reference to Diversion header “counter” parameter value

$dp - reference to port of destination uri

$dP - reference to transport protocol of destination uri

$ds - reference to destination set

$du - reference to destination uri

If loose_route() returns TRUE a destination uri is set according to the first Route header. $du is also set if lookup() function of 'registrar' module finds contact(s) behind NAT. You can set $du to any SIP URI.

 sip:kamailio.org
 sip:pbx123.kamailio.org;transport=udp
 sip:[2001:DB8::33:2]:5980;transport=tls

It is R/W variable (you can assign values to it directly in configuration file)

To reset $du:

$du = null;

$fd - reference to domain in URI of 'From' header

$fn - reference to display name of 'From' header

$fs - reference to the forced socket for message sending (if any) in the form proto:ip:port

It is R/W variable (you can assign values to it directly in configuration file). Transport proto can be omitted when assigning value, in which case it is taken from destination URI of the message.

$ft - reference to tag parameter of 'From' header

$fti - reference to tag parameter of 'From' header as it was in the initial request (e.g., initial INVITE).

The value From tag in the initial request can be in the To tag, if the request within the dialog is sent by the callee. This variable detect who sent the request within the dialog and returns the proper value that was in the From tag of the request initiating the dialog.

It is exported by rr module and has to be used after loose_route(). The append_fromtag parameter is required to be set to 1 in order to have this variable returning the right value.

$fu - reference to URI of 'From' header

It is R/W variable (you can assign values to it directly in configuration file)

Note that changing the From: header may break backwards compatibility with SIP 1.0 devices.

$fU - reference to username in URI of 'From' header

It is R/W variable (you can assign values to it directly in configuration file)

Note that changing the From: header may break backwards compatibility with SIP 1.0 devices.

$mb - reference to SIP message buffer

$mf - reference to message/transaction flags set for current SIP request

It is R/W variable (you can assign values to it directly in configuration file)

$mF -reference to message/transaction flags set for current SIP request in hexa-decimal

It is R/W variable (you can assign values to it directly in configuration file)

$mi - reference to SIP message id

$ml - reference to SIP message length

$mt - returns 1 if the sip message is a request, returns 2 if the sip message is a reply

$od - reference to domain in request's original R-URI

$op - reference to port of original R-URI

$oP - reference to transport protocol of original R-URI

$ou - reference to request's original URI

$oU - reference to username in request's original URI

$pd - reference to domain in request's P-Preferred-Identity header URI (see RFC 3325)

$pn - reference to Display Name in request's P-Preferred-Identity header (see RFC 3325)

$pp - reference to process id (pid)

$pr or $proto - protocol of received message (udp, tcp, tls, sctp, ws, wss)

$pU - reference to user in request's P-Preferred-Identity header URI (see RFC 3325)

$pu - reference to URI in request's P-Preferred-Identity header (see RFC 3325)

$rb - reference to message body

$rc - reference to returned code by last invoked function

$retcode - same as $rc

$rd - reference to domain in request's URI (without port) or to the Namespace Specific String of a URN (see RFC 2141)

It is R/W variable (you can assign values to it directly in configuration file)

$rdir(key) - get the direction of the request within dialog.

The direction is 'downstream' if sent by the caller and 'upstream' if sent by callee.

The key can be:

• id - the returned value is an integer: 1 - for direction downstream, 2 - for direction upstream
• name - the returned value is a string: 'downstream' or 'upstream'

Example:

if($rdir(name)=="upstream") {
  xlog("request was sent by callee\n");
}

The variable is exported by rr module and append_fromtag parameter must be enabled. The variable has to be used after loose_route() function.

$re - reference to Remote-Party-ID header URI

$rm - reference to request's method. Works also for replies (by using the CSeq header)

$rmid - returns internal integer representation of SIP method type

$route_uri - returns the string with URI field in the first Route header

$rp - reference to port of R-URI

It is R/W variable (you can assign values to it directly in configuration file)

$rP - reference to transport protocol of R-URI

$rr - reference to reply's reason phrase (the text after reply code)

$rs - reference to reply's status (status-code, response-code, reply-code)

$rt - reference to URI of refer-to header

$ru - reference to request's URI (address in the first line of a SIP request)

It is R/W variable (you can assign values to it directly in configuration file)

$rU - reference to username in request's URI or to the Namespace Identifier of a URN (see RFC 2141)

It is R/W variable (you can assign values to it directly in configuration file)

$ruid - the Record internal Unique ID for the location record selected by calling registrar:lookup()

$rz - returns R-URI scheme, possible values: sip, sips, tel, tels and urn, R-URI scheme parsing error should be reflected by value: none

$Ri - reference to IP address of the interface where the request has been received

$Rp - reference to the port where the message was received

$sbranch(attr) - class of variables allowing to manage the values of attributes for static branch. The static branch is internal structure that is used by the functions sbranch_push_ruri() and sbranch_append() from pv module, enabling more flexibility in updating the R-URI (first) branch attributes as well as extra branches (e.g., for parallel forking).

The attr can be any of the supported values for $branch(attr) class of variables – see above for proper details.

Example of usage:

sbranch_reset();
$sbranch(uri) = "sip:127.0.0.1:5080";
$sbranch(dst_uri) =  "sip:127.0.0.1:5090";
$sbranch(path) =  "sip:127.0.0.1:5090, sip:127.0.0.1:5094";
$sbranch(send_socket) =  "udp:127.0.0.1:5060";
sbranch_set_ruri();

$sf - reference to script flags - decimal output

$sF - reference to script flags - hexa output

$si - reference to IP source address of the message

$sp - reference to the source port of the message

$stat(name) - return the value of statistic item specified by 'name'

$su - returns the representation of source address (ip, port, proto) as SIP URI. If the proto is UDP, then it is not added (being the default transport protocol).

Its value looks like:

"sip:ip:port" -- if proto is UDP
"sip:ip:port;transport=proto"  -- if proto is not UDP

Note that WS and WSS are both represented by transport=ws, conforming with the IETF RFC for SIP over WebSocket.

$su - returns the representation of source address (ip, port, proto) as full SIP URI. The proto UDP is added also as transport parameter.

Its value looks like:

"sip:ip:port;transport=proto"

$td - reference to domain in URI of 'To' header

$tn - reference to display name of 'To' header

$tt - reference to tag parameter of 'To' header

$tti - reference to tag parameter of 'To' header as it was in the SIP response to the initial request (e.g., 200ok to the initial INVITE).

The value To tag in the initial transaction can be in the From tag, if the request within the dialog is sent by the callee. This variable detect who sent the request within the dialog and returns the proper value that was in the To tag of the transaction initiating the dialog.

It is exported by rr module and has to be used after loose_route(). The append_fromtag parameter is required to be set to 1 in order to have this variable returning the right value.

$tu - reference to URI of 'To' header

$tU - reference to username in URI of 'To' header

$Tb - reference to unix timestamp of the time at which kamailio was started (boot time)

$Tf - reference string formatted time

Note: the system time is retrieved only once for each processed SIP message. Subsequent calls of $Tf for same SIP message will return same value.

$TF - reference string formatted time

Note: the system time is computed for each call of $TF. Subsequent calls of $TF for same SIP message may return different values.

$Ts - reference to unix time stamp

Note: the system time is retrieved only once for each processed SIP message. Subsequent calls of $Ts for same SIP message will return same value.

$TS - reference to unix time stamp

Note: the system time is computed for each call of $TS. Subsequent calls of $TS for same SIP message may return different values.

$ua - reference to user agent header field

$avp(id) - the value of the AVP identified by 'id'.

$(avp(id)[N]) - represents the value of N-th AVP identified by 'id'.

The 'id' can be:

• “[(s|i):]name” - name is the id of an AVP; 's' and 'i' specifies if the id is string or integer. If missing, it is considered to be string.
• “name” - the name is an AVP alias, or if the alias is not found, it is a string name
• pseudo variable - if value of pv is integer, id is integer, if string, id is string

$(avp(id)[0]) can be written in shorter form as $avp(id) and $avp(s:name) as $avp(name).

AVPs are special variables that are attached to SIP transactions. It is a list of pairs (name,value). Before the transaction is created, the AVP list is attached to SIP request. Note that the AVP list works like a stack, last added value is retrieved first, and there can be many values for same AVP name, an assignment to the same AVP name does not overwrite old value, it will add the new value in the list.

To delete the first AVP with name 'id' you have to assign to it '$null':

$avp(id) = $null;

To delete all the AVP with name 'id' you have to assign $null to the index '*':

$(avp(id)[*]) = $null;

To overwrite the value of the AVP with name 'id' you have to assign the new value to the index '*':

$(avp(id)[*]) = newvalue;

The value of an AVP can be integer or string. To assign a value as string, it has to be enclosed in double quotes. To assign the value as integer, it has to be a valid number given without quotes.

Example of usage:

$avp(x) = 1;  # assign of integer value
$avp(x) = 2;
$avp(y) = "abc"; # assign of string value
if($(avp(x)[1])==1) {
  ...
}
$(avp(x)[1]) = $null;

It is R/W variable (you can assign values to it directly in configuration file).

Return the min and max of expires value for current SIP message. Contact headers are checked with higher priority, if no expires parameter there, then Expires header is used

If none is found, $null is returned.

Possible 'key' values:

• $expires(min) - the minimum value for expires
• $expires(max) - the maximum value for expires

When there is only one expires value, then min and max return the same.

Example of usage:

if($expires(max)!=$null) {
    xlog("max expires value is: $expires(max)\n");
}

xavp - extended AVP's - are structures that can store multiple values. They work like a stack, much like AVPs, and are attached to SIP transactions. Each xavp has a name and can contain multiple named values, the structure name and the value name are separated by '⇒' like $xavp(root⇒branch) where “root” is the name of the structure and branch is a named value. To assign a value use

$xavp(root=>branch)="value";

Like avps, xavp act like a stack. To refer to an existing value, use an index. The newest xavp has index zero [0].

$xavp(root[0]=>newbranch)=12;

If you assign a value without an index, a new xavp is allocated and the old one is pushed up the stack, becoming index [1]. Old index [1] becomes [2] etc.

$xavp(example=>name)="one";
#create new
$xavp(example=>name)="two";
#add extra value to "two"
$xavp(example[0]=>value)="John";
#add value to first variable - "one"
$xavp(example[1]=>value)="Anna";

Another example:

# Create new xavp
$xavp(sf=>uri)="sip:10.10.10.10";
 
#assign values
$xavp(sf[0]=>fr_timer)=10;
$xavp(sf[0]=>fr_inv_timer)=15;
$xavp(sf[0]=>headers)="X-CustomerID: 1234\r\n";
 
#create new xavp, moving previous one to sf[1]
$xavp(sf=>uri)="sip:10.10.10.11";
$xavp(sf[0]=>fr_timer)=20;
$xavp(sf[0]=>fr_inv_timer)=35;
 
#Create a third xavp
$xavp(sf=>uri)="sip:10.10.10.12";
$xavp(sf[0]=>fr_timer)=10;
$xavp(sf[0]=>fr_inv_timer)=15;
$xavp(sf[0]=>headers)="X-CustomerID: pw45\r\n";

xavps are read and write variables. You can create multilevel xavps, as xavps may contain xavps.

$hdr(name) - represents the body of first header identified by 'name'

$(hdr(name)[N]) - represents the body of the N-th header identified by 'name'.

If [N] is omitted then the body of the first header is printed. The first header is got when N=0, for the second N=1, a.s.o. In case of a comma-separated multi-body headers, it returns all the bodies, comma-separated. To print the last header of that type, use -1, or other negative values to count from the end. No white spaces are allowed inside the specifier (before }, before or after {, [, ] symbols). When N='*', all headers of that type are printed.

The module should identify compact header names. It is recommended to use dedicated specifiers for headers (e.g., $ua for user agent header), if they are available – they are faster.

Example of usage:

if($hdr(From)=~"kamailio\.org") {
...
}

It is read-only variable. You can remove or add headers using functions from textops module.

$var(name) - refers to variables that can be used in configuration script, having integer or string value. This kind of variables are faster than AVPs, being referenced directly to memory location.

Example of usage:

$var(a) = 2; #-- sets the value of variable 'a' to integer '2'
$var(a) = "2"; #-- sets the value of variable 'a' to string '2'
$var(a) = "sip:" + $au + "@" + $fd; #-- compose a value from authentication username and From URI domain
$var(a) = 3 + (7&(~2));
 
if( $var(a) & 4 ) {
  xlog("var a has third bit set\n");
}

Note: Setting a variable to $null is actually initializing the value to integer '0'. This type of script variables doesn't have $null value.

$var(x) = $null;
 
if($var(x)==0) { # this is true
  ...
}

Note: A script variable persists over the Kamailio process in which it was initialized, so be sure of giving it a new value before reading it or you'll get the value asigned in any other previous message processed by the same Kamailio process (pid).

It is R/W variable (you can assign values to it directly in configuration file)

pv module can be used to initialize the script variables.

Same as $var(name) – added to pair with $vn(name).

Similar to $var(name) and able to hold $null (which is the default value). The value is kept in private memory (pkg) and it is persistent across SIP message processing, within the space of each Kamailio process.

Example of usage:

$vn(x) = 1;
$vn(x) = "abc";
$vn(x) = $null;
 
if($vn(x) == $null) { ... }

$shv(name) - it is a class of pseudo-variables stored in shared memory. The value of $shv(name) is visible across all Kamailio processes. Each “shv” has single value and it is initialised to integer 0. You can use “shvset” parameter of pv module to initialize the shared variable. The module exports a set of MI functions to get/set the value of shared variables.

Example - shv(name) pseudo-variable usage:

...
modparam("pv", "shvset", "debug=i:1")
...
if ($shv(debug) == 1) {
	xlog("request: $rm from $fu to $ru\n");
}
...

It is R/W variable (you can assign values to it directly in configuration file)

$time(name) - the PV provides access to broken-down time attributes.

The 'name' can be:

• sec - return seconds (int 0-59)
• min - return minutes (int 0-59)
• hour - return hours (int 0-23)
• mday - return the day of month (int 0-59)
• mon - return the month (int 1-12)
• year - return the year (int, e.g., 2008)
• wday - return the day of week (int, 1=Sunday - 7=Saturday)
• yday - return the day of year (int, 1-366)
• isdst - return daylight saving time status (int, 0 - DST off, >0 DST on)

Example - time(name) pseudo-variable usage:

...
if ($time(year) == 2008) {
    xlog("request: $rm from $fu to $ru in year 2008\n");
}
...

$timef(format) - return current time as formatted by strftime 'format'. See 'man strftime' to see the available time attribute specifiers.

Example:

xlog("Today is $timef(%m/%d/%y)\n");

$sel(name) - return the value of select specified by name. select refers a class of config variables introduced by SER 2.0, allowing to select and return parts of sip messages and not only.

List of available selects:

• http://www.kamailio.org/wiki/cookbooks/devel/selects

Example:

if($sel(via[1].host)=="10.10.10.10")
{
  ...
}

$snd(name) - return attributes of the address from where the request is going to be sent (local socket).

$sndfrom(name) - return attributes of the address from where the request is going to be sent (local socket, same as $snd(name)).

The name can have same values as for $sndto(…).

$sndto(name) - return attributes of the address to where the request is going to be sent (remote socket).

They are available in onsend_route. The name can be:

• ip - IP address of destination
• af - address family to be used to send (numeric)
• port - port of destination address
• proto - transport protocol to be used to send (numeric)
• buf - entire send buffer as string
• len - length of outgoing packet (length of above buf)

Example:

onsend_route {
  if($snd(ip)=="10.10.10.10")
  {
    ...
  }
}

$BM_time_diff - the time difference elapsed between calls of bm_start_timer(name) and bm_log_timer(name). The value is 0 if no bm_log_timer() was called.

Return the attribute of the current processed dialog.

It is R/O variable.

The 'attr' can be:

• h_id - hash id
• h_entry - hash entry
• ref - reference count
• state - state of dialog
• to_rs - To route set
• from_rs - From route set
• dflags - dialog internal flags
• sflags - dialog script flags
• callid - sip call id
• to_uri - To uri
• to_tag - To tag
• from_uri - From uri
• from_tag - From tag
• toroute - timeout route
• lifetime - timeout inteval
• start_ts - start timestamp
• to_cseq - To CSeq
• from_cseq - From CSeq
• to_contact - To contact address
• from_contact - From contact address
• to_bindaddr - To bind address
• from_bindaddr - From bind address

Return the attribute of the context for current processed dialog.

It is R/W variable.

The 'attr' can be:

• set
• flags
• timeout_route
• timeout_bye

Store and retrieve custom variable for current processed dialog.

It is R/W variable.

The 'key' can be any string.

* type - get variable type. Possible types are: atom, integer, list, string, tuple, pid and ref.

* length - get length of list or tuple.

* format - prints a term, in clear text. It tries to resemble the term printing in the Erlang shell.

$erl_atom(name) pseudo variable allows create analog to Erlang atom data type. Erlang atom is a literal, a constant with name. Formatted output pseudo variable atom could be enclosed in single quotes (') if it does not begin with a lower-case letter or if it contains other characters than alphanumeric characters, underscore (_), or @.

Example:

$erl_atom(A) = "node@host.tld";
 
xlogl("L_DEBUG","$$erl_atom(A): $erl_atom(A=>format)\n");

Compound data type with a variable number of terms. Formally, a list is either the empty list [] or consists of one or more elements.

Example:

$erl_atom(E) = "example";
$erl_list(L) = "list";
$erl_list(L) = "of";
$erl_list(L) = $erl_atom(E);
 
xlogl("L_DEBUG","length(L): $erl_list(L=>length), format(L): $erl_list(L=>format)\n");
 
# empty list
$erl_tuple(E[*]) = $null;

From the Erlang point of view the tuple compound data type with a fixed number of terms. The module implementation of tuple has the same behavior as the list.

Example:

$erl_atom(e) = "error";
 
$erl_tuple(T) = "badrpc";
$erl_tuple(T) = $erl_atom(e);
 
xlogl("L_DEBUG","length(T): $erl_tuple(T=>length), format(T): $erl_tuple(T=>format)\n");

Holds Eralng process identifier. Provides access to Erlang PID value and could be used in send message.

Holds Erlang reference. Provides access to reference value and could be used in send message.

Generic pseudo variable to acts as other pseudo variables exported from Erlang module.

Access hash table entries.

It is R/W variable, you can assign values to it directly in configuration file. Hash table entry can be deleted by assigning value $null to it.

The “htname” must be a hash table name defined via “htable” parameter.

The “key” can be:

• static string - set of characters without pseudo-variables
• dynamic string - set of characters that include pseudo-variables. The pseudo-variables will be evaluated at runtime.

...
modparam("htable", "htable", "a=>size=4;")
...
$sht(a=>$au) = 1;
$sht(a=>$ru) = $fu;
...

Access hash table entry expire value. Value represents the seconds until the htable entry will expire and be deleted from htable.

It is R/W variable, you can assign values to it directly in configuration file.

The “htname” must be a hash table name defined via “htable” parameter and have auto-expire greater than 0.

The “key” can be:

• static string - set of characters without pseudo-variables
• dynamic string - set of characters that include pseudo-variables. The pseudo-variables will be evaluated at runtime.

...
modparam("htable", "htable", "a=>size=4;autoexpire=120;")
...
$sht(a=>$au) = 1;
$shtex(a=>$au) = 10;
...

Count items matching the name by regexp.

The “htname” must be a hash table name defined via “htable” parameter.

The exp can be:

• reqexp - match by regular expression 'regexp'
• ~~regexp - match by regular expression 'regexp'
• ~%prefix - match by right prefix
• %~prefix - match by left prefix
• ==value - match by string value
• eqvalue - match by integer value
• * * - (two asterisks next to each other) - count all items

The exp can contain pseudo-variables.

...
modparam("htable", "htable", "a=>size=4;")
...
$sht(a=>abc) = 1;
$shtex(a=>ade) = 10;
xlog("$shtcn(a=>a.*)");
...

Count items matching the value by regexp.

The “htname” must be a hash table name defined via “htable” parameter.

The exp must follow same rules as for $shtcn(…).

...
modparam("htable", "htable", "a=>size=4;")
...
$sht(a=>abc) = "xyz";
$shtex(a=>ade) = "xwt";
xlog("$shtcv(a=>x.*)");
...

Atomic increment of the value for the hash table item.

...
modparam("htable", "htable", "a=>size=4;")
...
$sht(a=>$au) = 1;
xlog("==== $shtinc(a=>$au)\n");
...

Atomic decrement of the value for the hash table item.

...
modparam("htable", "htable", "a=>size=4;")
...
$sht(a=>$au) = 1;
xlog("==== $shtdec(a=>$au)\n");
...

Access hash table entries stored in the memcached server.

It is R/W variable, you can assign values to it directly in configuration file.

The “key” can be:

• static string - set of characters without pseudo-variables
• dynamic string - set of characters that include pseudo-variables. The pseudo-variables will be evaluated at runtime.

When assigning values, the default expiry will be used.

...
$mct($au) = 1;
$mct($ru) = $fu;
$mct(test) = 1;
xlog("stored value is $mct(test)");
$mct(test) = null; # delete it
xlog("stored value is $mct(test)"); # will return <null>
...

Using this alternative format, the default expiry may be overidden by including a custom value at time of assignment.

...
$mct(test=>30) = 1; # set expire time to 30 seconds
xlog("stored value is $mct(test)");
# sleep 30 seconds
xlog("stored value is $mct(test)"); # will return <null>
...

Do a atomic increment operation on the value stored in memcached. You need to add a value previously.

It is R/W variable, you can assign values to it directly in configuration file.

The “key” can be:

• static string - set of characters without pseudo-variables
• dynamic string - set of characters that include pseudo-variables. The pseudo-variables will be evaluated at runtime.

...
$mct(cnt) = 1;
$mcinc(cnt) = 2; # increment by 2
xlog("counter is now $mct(cnt)");
...

Do a atomic decrement operation on the value stored in memcached. You need to add a value previously.

It is R/W variable, you can assign values to it directly in configuration file.

The “key” can be:

• static string - set of characters without pseudo-variables
• dynamic string - set of characters that include pseudo-variables. The pseudo-variables will be evaluated at runtime.

...
$mct(cnt) = 10;
$mcdec(cnt) = 2; # decrement by 2
xlog("counter is now $mct(cnt)");
...

• name - id to refer the documet
• spec - specifier:
  • doc - set/get the document as text
  • xpath:xpath-expression - evaluate xpath expression

Example:

$xml(x=>doc) = '<?xml version="1.0" encoding="UTF-8"?><a><b>test</b></a>';
xlog("content of node b: $xml(x=>xpath:/a/b/text())\n");
$xml(x=>xpath:/a/b) = "1234";

• the index (starting with 1 for the first branch) of the branch for which is executed the branch_route[]. If used outside of branch_route[] block, the value is '0'.

• the ruid stored in the current branch of the transaction. The ruid is stored in a branch from the details in a contact binding. In a event_route[tm:branch-failure] block, this is the ruid of the branch that sent a failure reply. In a failure_route[] block, this is the ruid of the winning failure response.

• the code of the reply, as follows: in request_route will be the last stateful sent reply; in reply_route will be the current processed reply; in failure_route will be the negative winning reply. In case of no-reply or error, '0' value is returned

• can be used in reply routes or inside the modules to get access to attributes of the request belonging to same transaction as the reply

route {
  t_on_reply("1");
  t_relay();
}

onreply_route[1] {
  xlog("Request SRCIP:PORT = $T_req($si):$T_req($sp)\n");
}

• can be used in failure routes or inside the modules to get access to attributes of the winning reply belonging to same transaction as the request

route {
  t_on_failure("1");
  t_relay();
}

failure_route[1] {
  xlog("Reply SRCIP:PORT = $T_rpl($si):$T_rpl($sp)\n");
}

• can be used in request routes or inside the modules to get access to attributes of the INVITE request while processing a CANCEL.

route {
  if(is_method("CANCEL"))
  {
     if($T_inv($mf) & 1 )
     {
        # first flag is set in the INVITE transaction
     }
  }
}

• pseudo-variable class to access TM attributes

The name can be:

• id_index - return the internal index of current transaction
• id_label - return the internal label of current transaction
• reply_code - alias to $T_reply_code
• branch_index - alias to $T_branch_idx
• reply_type - 1 if it is a local generated reply, 0 - if no reply for transaction or it is a received reply

Note: the pair (id_index,id_label) uniquely identifies a transaction.

• pseudo-variable class to access TM branch attributes

The name can be:

• flags - Flags of the branch. In a event_route[tm:branch-failure] block, this is the flags of the branch that sent a failure reply. In a failure_route[] block, this is the flags of the winning failure response.
• uri - the R-URI of the branch. Can be used in onreply_route[id] - reply route blocks executed by tm module. For other routing blocks handling requests, the R-URI is returned by $ru

• used to build the input for uac_send_req() function of UAC module

The key can be:

• method - SIP method
• ruri - request URI
• furi - From URI
• turi - To URI
• ouri - Outbound proxy URI
• hdrs - SIP Headers
• body - Body
• auser - authentication username
• apasswd - authentication password
• sock - local socket to be used for sending (proto:address:port)
• callid - SIP-Call-ID of the generated request (by default, a call-id is generated)
• all - alias useful to reset all fields - $uac_req(all) = $null;
• evroute - it has to be set to 1 in order to execute event_route[uac:reply] when reply is received
• evcode - reply code for the request sent with uac_req_send(), available inside event_route[uac:reply]
• evtype - is 1 if the reply was received via network, 2 if the reply was locally generated (e.g., retransmission timeout), available inside event_route[uac:reply]

$uac_req(method)="OPTIONS";
$uac_req(ruri)="sip:alice@kamailio.org";
$uac_req(turi)="sip:alice@kamailio.org";
$uac_req(furi)="sip:daniel@kamailio.org";
$uac_req(evroute) = 1;
uac_req_send();
...
event_route[uac:reply] {
  xlog("request sent to $uac_req(ruri) completed with code: $uac_req(evcode)\n");
}

• Number of Record Routes in received SIP request or reply.

• If topmost Record Route in received SIP request or reply is a double Record Route, value of $rr_top_count is 2. If it a single Record Route, value of $rr_top_count is 1. If there is no Record Route(s), value of $rr_top_count is 0.

• return the key of fetched item from queue q

• return the value of fetched item from queue q

...
mq_add("myq", "$rU", "call from $fU at $Tf");
...
while(mq_fetch("myq"))
{
   xlog("$mqk(myq) - $mqv(myq)\n");
}
...

Seconds and microseconds taken from struct timeval.

• $TV(s) - seconds (cached at first call per sip message)
• $TV(u) - microseconds (cached at first call per sip message)
• $TV(sn) - seconds (not cached)
• $TV(un) - microseconds (not cached)
• $TV(Sn) - string representation seconds.microseconds (not cached)

Return attributes of next hop for the SIP request. Address is taken from dst_uri, if set, if not from new r-uri or original r-uri.

• $nh(u) - uri (lower case u)
• $nh(U) - username (upper case u)
• $nh(d) - domain
• $nh(p) - port (lower case p)
• $nh(P) - transport protocol (upper case p)

Variables exported by GeoIP module, returning geo-location attributes. The attributes are populated upon calling function geoip_match(ipaddr, pvc).

pvc (container id) is second parameter of geoip_match(..) and key can be:

• cc - country code
• tz - time zone
• zip - postal code
• lat - latitude
• lon - longitude
• dma - dma code
• ips - ip start
• ipe - ip end
• city - city
• area - area code
• regc - region
• regn - region name
• metro - metro code
• contc - continent code

You can call several time geoip_match(ipaddr, pvc) with different ip address and containers in your config, to compare, for example, attributes of source and destination of a call.

geoip_match("$si", "src");
geoip_match("$nh(d)", "dst");
 
if($gip(src=>cc)==$gip(dst=>cc))
{
    # source and destination from same country
}

The TLS/SSL version which is used on the TLS connection from which the message was received. String type.

The TLS/SSL description of the TLS connection from which the message was received. String type.

The TLS/SSL cipher which is used on the TLS connection from which the message was received. String type.

The number of cipher bits which are used on the TLS connection from which the message was received. String and Integer type.

The version of the certificate. String type.

The version of the certificate. String type.

The serial number of the certificate. String and Integer type.

The serial number of the certificate. String and Integer type.

ASCII dump of the fields in the subject section of the certificate. String type. Example:

  /C=AT/ST=Vienna/L=Vienna/O=enum.at/CN=enum.at

ASCII dump of the fields in the issuer section of the certificate. String type.

ASCII dump of the fields in the subject section of the certificate. String type.

ASCII dump of the fields in the issuer section of the certificate. String type.

commonName in the subject section of the certificate. String type.

commonName in the issuer section of the certificate. String type.

commonName in the subject section of the certificate. String type.

commonName in the issuer section of the certificate. String type.

localityName in the subject section of the certificate. String type.

localityName in the issuer section of the certificate. String type.

localityName in the subject section of the certificate. String type.

localityName in the issuer section of the certificate. String type.

countryName in the subject section of the certificate. String type.

countryName in the issuer section of the certificate. String type.

countryName in the subject section of the certificate. String type.

countryName in the issuer section of the certificate. String type.

stateOrProvinceName in the subject section of the certificate. String type.

stateOrProvinceName in the issuer section of the certificate. String type.

stateOrProvinceName in the subject section of the certificate. String type.

stateOrProvinceName in the issuer section of the certificate. String type.

organizationName in the subject section of the certificate. String type.

organizationName in the issuer section of the certificate. String type.

organizationName in the subject section of the certificate. String type.

organizationName in the issuer section of the certificate. String type.

organizationalUnitName in the subject section of the certificate. String type.

organizationalUnitName in the issuer section of the certificate. String type.

organizationalUnitName in the subject section of the certificate. String type.

organizationalUnitName in the issuer section of the certificate. String type.

email address in the “subject alternative name” extension. String type.

email address in the “subject alternative name” extension. String type.

hostname (DNS) in the “subject alternative name” extension. String type.

hostname (DNS) in the “subject alternative name” extension. String type.

URI in the “subject alternative name” extension. String type.

URI in the “subject alternative name” extension. String type.

ip address in the “subject alternative name” extension. String type.

ip address in the “subject alternative name” extension. String type.

• URL of http request.

This class of pseudo-variables is exported by MSRP module and give access to attributes of MSRP frames.

The entire content of MSRP frame - first line, headers, body and end-line.

The body of MSRP frame.

The code of MSRP replies.

The headers in a MSRP frame.

The body of Message-Id header.

The method of a MSRP request.

The length of entire MSRP frame.

The session id for MSRP frame. It is taken from the first MSRP URI in To-Path header.

The reason text in a MSRP reply.

The URI for current hop - it is the first URI in To-Path header.

The length of the body in MSRP frame.

The transaction ID from the first line of MSRP frame.

The MSRP URI of the previous hop - the first address in From-Path header.

The URI of the next hop - the second address in To-Path header.

The last hop URI - the last address in To-Path header.

The address of the previous hop set as MSRP URI using received source IP and port.

The local socket where the MSRP frame was received, set as **proto:ipaddr:port“.

The URI of the first hop - the last address in From-Path header.

The number of previous hops - it is the number of addresses in From-Path header.

The number of next hops - it is the number of addresses in To-Path header minus 1 (the first address in To-Path is current hop).

The internal integer id for TCP/TLS connection.

Returns the value of the Address presentation restricted indicator contained in the Calling Party Number header of the IAM message if it exists. Returns -1 if there isn't a Calling Party Number header.

Returns the value of the Screening Indicator contained in the Calling Party Number header of the IAM message if it exists. Returns -1 if there isn't a Calling Party Number header.

Returns the value of the Hop Counter for the IAM message if it exists. Returns -1 if there isn't a hop counter.

Returns the value of the Calling Party Category for the IAM message. Returns -1 if there is a parsing error.

Returns the value of the Nature of Address Indicator of the Calling Party for the IAM message. Returns -1 if there is a parsing error or if the Calling Party Number is not present.

Returns the value of the Nature of Address Indicator of the Called Party for the IAM message. Returns -1 if there is a parsing error.

Returns the value of the Event Info header of the CPG message. Returns -1 if there is a parsing error.

Attributes related to configuration file.

The key can be:

• line - return current line in config
• name - return the name of current config file

Example:

send_reply("404", "Not found at line $cfg(line)");

This variable stores the DNS result details after a call of dns_query(hostname, pvid) function from ipops module.

• pvid can be any string
• key can be:
  • count - number of addresses
  • ipv4 - set to 1 if at least one ipv4 address (otherwise 0)
  • ipv6 - set to 1 if at least one ipv6 address (otherwise 0)
  • addr[index] - the address as string from position index in the list (0 based indexing)
  • type[index] - the type of address from position index in the list (0 based indexing), the value is 4 for ipv4 and 6 for ipv6

The index can be an integer or a variable with integer value. First address has the index 0. If negative value, the returned address is counted from the end of the list, -1 being the last address. If no index is provided, then the first address is returned.

if(dns_query("test.com", "xyz"))
{
    xlog(" number of addresses: $dns(xyz=>count)\n");
    xlog(" ipv4 address found: $dns(xyz=>ipv4)\n");
    xlog(" ipv6 address found: $dns(xyz=>ipv6)\n");
    $var(i) = 0;
    while($var(i)<$dns(xyz=>count)) {
        xlog(" #[$var(i)] type ($dns(xyz=>type[$var(i)]))"
             " addr [$dns(xyz=>addr[$var(i)])]\n");
        $var(i) = $var(i) + 1;
    }
}

Give local hostname details (implemented by ipops module).

The key can be:

• n - the hostname
• f - the fullname
• d - the domain
• i - the ip address

xlog("local hostanme is $HN(n)\n");

Returns a random value from the [0 - 2^31) range.

(Part of the cfgutils module)

if (rand_event()) {
  $avp(i:10) = ($RANDOM / 16777216); # 2^24
  if ($avp(i:10) < 10) {
     $avp(i:10) = 10;
  }
  append_to_reply("Retry-After: $avp(i:10)\n");
  sl_send_reply("503", "Try later");
  exit;
};
# normal message processing follows

This variable gives access to JSONRPC reply after executing jsonrpc_exec(…) in kamailio.cfg.

The key can be:

• code - code for the JSONRPC response
• text - text of the code for the JSONRPC response
• body - the body of the JSONRPC response

This variable gives access to attributes of the current subscription. The variable has to be used after executing handle_subscription() in order to provide accurate values.

The key can be:

• uri - subscription URI. Useful in particular for subscriptions within the dialog, when the request URI in SUBSCRIBE is the Contact address from the initial subscription.

$C(xy) - reference to an escape sequence. “x” represents the foreground color and “y” represents the background color.

Colors could be:

• x : default color of the terminal
• s : Black
• r : Red
• g : Green
• y : Yellow
• b : Blue
• p : Purple
• c : Cyan
• w : White

A few examples of usage.

Example 1. Pseudo-variables usage

...
avp_aliases="uuid=I:50"
...
route {
...
    $avp(uuid)="caller_id";
    $avp(i:20)= $avp(uuid) + ": " + $fu;
    xdbg("$(C(bg))avp(i:20)$(C(xx)) [$avp(i:20)] $(C(br))cseq$(C(xx))=[$hdr(cseq)]\n");
...
}
...

Following are some examples how RURI and DURI are parsed, for SIP-URIs, tel-URIs and Service-URNs:

 === Request URI contains SIP URI ===
$ru = "sip:example.com"
$rz = "sip"
$rU = "<null>"
$rd = "example.com"
$rp = "5060"
$rP = "UDP"

=== Request URI contains SIP URI ===
$ru = "sips:john.q.public:hispw@example.com:6061;transport=tls;foo=bar"
  $rz = "sips"
  $rU = "john.q.public"
  $rd = "example.com"
  $rp = "6061"
  $rP = "tls"

=== Request URI contains service URN ===
$ru = "urn:service:sos.fire"
  $rz = "urn"
  $rU = "service"
  $rd = "sos.fire"
  $rp = "5060"
  $rP = "UDP"

=== Request URI contains tel: URI ===
$ru = "tel:+1-201-555-0123"
  $rz = "tel"
  $rU = "+1-201-555-0123"
  $rd = "<null>"
  $rp = "5060"
  $rP = "UDP"

=== Request URI contains tel: URI with phone-context ===
$ru = "tel:7042;phone-context=example.com"
  $rz = "tel"
  $rU = "7042"
  $rd = "<null>"
  $rp = "5060"
  $rP = "UDP"

=== Destination URI (must be a SIP(S) URI) ===
$du = "sip:example.com:6061;transport=tls;foo=bar"
  $dd = "example.com"
  $dp = "6061"
  $dP = "tls"