Version: 3.0.x
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 “$$”.
There is a set of predefined pseudo-variables, which have the name composed from one to three letters, and special pseudo-variables that are references to dynamic fields (AVP and Headers)
Pseudo-Variables are implemented by various modules, most of them are provided by pv.
Pseudo-variables can be used with many modules, among them:
Predefined pseudo-variables are listed in alphabetical order.
$$ - represents the character '$'
$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.
$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 for all of them.)
The 'name' can be:
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;
}
$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
$bF - reference to branch flags of branch 0 (RURI) - hexa output
$bs - body size
$ci - reference to body of call-id header
$cl - reference to body of content-length header
$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 methode (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
$di - reference to Diversion header URI
$dip - reference to Diversion header "privacy" parameter value
$dir - reference to Diversion header "reason" 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.
It is R/W variable (you can assign values to it directly in configuration file)
To reset $du:
$du = null;
$err.class - the class of error (now is '1' for parsing errors)
$err.level - severity level for the error
$err.info - text describing the error
$err.rcode - recommended reply code
$err.rreason - recommended reply reason phrase
$fd - reference to domain in URI of 'From' header
$fn - reference to display name of 'From' header
$ft - reference to tag parameter of 'From' header
$fu - reference to URI of 'From' header
$fU - reference to username in URI of 'From' header
$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
$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)
$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)
$rd - reference to domain in request's URI
It is R/W variable (you can assign values to it directly in configuration file)
$rb - reference to message body
$rc - reference to returned code by last invoked function
$retcode - same as $rc
$re - reference to Remote-Party-ID header URI
$rm - reference to request's method. Works also for replies (by using the CSeq 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
$rs - reference to reply's status
$rt - reference to URI of refer-to header
$ru - reference to request's URI
It is R/W variable (you can assign values to it directly in configuration file)
$rU - reference to username in request's URI
It is R/W variable (you can assign values to it directly in configuration file)
$Ri - reference to IP address of the interface where the request has been received
$Rp - reference to the port where the message was received
$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'
$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)
$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
$tu - reference to URI of 'To' header
$tU - reference to username in URI of 'To' header
$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)[N]) - represents the value of N-th AVP identified by 'id'.
The 'id' can be:
* "[si]: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
It is R/W variable (you can assign values to it directly in configuration file)
$(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, no other negative values are supported now. 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 most of compact header names (the ones recognised by SIP-Router which should be all at this moment), if not, the compact form has to be specified explicitly. It is recommended to use dedicated specifiers for headers (e.g., %ua for user agent header), if they are available – they are faster.
$var(name) - refers to variables that can be used in configuration script, having integer or string value. This kind of variables are faster the AVPs, being referenced directly to memory location. The value of script variables persists over the processing of SIP messages, being specific per each SIP-Router process.
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) = 3 + (7&(~2));
$var(a) = "sip:" + $au + "@" + $fd; -- compose a value from authentication username and From URI domain
if( [ $var(a) & 4 ] ) {
xlog("var a has third bit set\n");
}
Setting a variable to null is actually initializing the value to integer '0'. Script variables don't have NULL value.
Note: A script variable persists over the SIP-Router 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 SIP-Router process (pid).
It is R/W variable (you can assign values to it directly in configuration file)
pv module can be used to initialise the script variables.
$shv(name) - it is a class of pseudo-variables stored in shared memory. The value of $shv(name) is visible across all openser processes. Each “shv” has single value and it is initialised to integer 0. You can use “shvset” parameter of pv module to initialize the shared variable. The module exports a set of MI functions to get/set the value of shared variables.
Example - shv(name) pseudo-variable usage:
...
modparam("pv", "shvset", "debug=i:1")
...
if ($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)
$time(name) - the PV provides access to broken-down time attributes.
The 'name' can be:
Example - time(name) pseudo-variable usage:
... if ($time(year) == 2008) { xlog("request: $rm from $fu to $ru in year 2008\n"); } ...
$sel(name) - return the value of select specified by name. select refers a class of config variables introduced by SER 2.0, allowing to select and return parts of sip messages and not only.
List of available selects:
Example:
if($sel(@via[1].host)=="10.10.10.10") { ... }
$snd(name) - return attributes of the address where the request is going to be sent. They are available in onsend_route. The name can be:
Example:
onsend_route { if($snd(ip)=="10.10.10.10") { ... } }
Return the attribute of the current processed dialog.
It is R/O variable.
The 'attr' can be:
Return the attribute of the context for current processed dialog.
It is R/W variable.
The 'attr' can be:
Access hash table entries.
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.
The “key” can be:
...
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:
...
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 “regexp” must be a regular expression.
...
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 “regexp” must be a regular expression.
...
modparam("htable", "htable", "a=>size=4;")
...
$sht(a=>abc) = "xyz";
$shtex(a=>ade) = "xwt";
xlog("$shtcv(a=>x.*)");
...
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:
...
$mct($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>
...
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:
...
$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:
...
$mct(cnt) = 10;
$mcdec(cnt) = 2; # decrement by 2
xlog("counter is now $mct(cnt)");
...
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";
route {
t_on_reply("1");
t_relay();
}
onreply_route[1] {
xlog("Request SRCIP:PORT = $T_req($si):$T_req($sp)\n");
}
route {
t_on_failure("1");
t_relay();
}
failure_route[1] {
xlog("Reply SRCIP:PORT = $T_rpl($si):$T_rpl($sp)\n");
}
route {
if(is_method("CANCEL"))
{
if($T_inv($mf) & 1 )
{
# first flag is set in the INVITE transaction
}
}
}
key can be:
$uac_req(method)="OPTIONS"; $uac_req(ruri)="sip:kamailio.org"; $uac_req(furi)="sip:kamailio.org"; $uac_req(turi)="sip:kamailio.org"; uac_send_req();
These pseudo variables are exported, and mainly used, by xlog module to print messages in many colors (foreground and background) using escape sequences.
$C(xy) - reference to an escape sequence. “x” represents the foreground color and “y” represents the background color.
Colors could be:
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"); ... } ...