Documentation? -> Script -> Script Statements

Statements you can use in the OpenSIPS config file while building the routing logic.

1. if

IF-ELSE statement

Prototype:

    if(expr) {
       actions;
    } else {
       actions;
    }

The 'expr' should be a valid logical expression.

The logical operators that can be used in 'expr':

• == - equal
• != - not equal
• =~ - regular expression matching (e.g. $rU =~ '^1800*' is "$rU begins with 1800" )
• !~ - regular expression not-matching
• > - greater
• >= - greater or equal
• < - less
• <= - less or equal
• && - logical AND
• || - logical OR
• ! - logical NOT
• [ ... ] - test operator - inside can be any arithmetic expression

Example of usage:

    if(is_method("INVITE"))
    {
        log("this sip message is an invite\n");
    } else {
        log("this sip message is not an invite\n");
    }

2. switch

SWITCH statement - it can be used to test the value of a pseudo-variable.

IMPORTANT NOTE: 'break' can be used only to mark the end of a 'case' branch (as it is in shell scripts). If you are trying to use 'break' outside a 'case' block the script will return error -- you must use 'return' there.

Example of usage:

    route {
        route(1);
        switch($retcode)
        {
            case -1:
                log("process INVITE requests here\n");
            break;
            case 1:
                log("process REGISTER requests here\n");
            break;
            case 2:
            case 3:
                log("process SUBSCRIBE and NOTIFY requests here\n");
            break;
            default:
                log("process other requests here\n");
       }

        # switch of R-URI username
        switch($rU)
        {
            case "101":
                log("destination number is 101\n");
            break;
            case "102":
                log("destination number is 102\n");
            break;
            case "103":
            case "104":
                log("destination number is 103 or 104\n");
            break;
            default:
                log("unknown destination number\n");
       }
    }

    route[1]{
        if(is_method("INVITE"))
        {
            return(-1);
        };
        if(is_method("REGISTER"))
            return(1);
        }
        if(is_method("SUBSCRIBE"))
            return(2);
        }
        if(is_method("NOTIFY"))
            return(3);
        }
        return(-2);
    }

NOTE: take care while using 'return' - 'return(0)' stops the execution of the script.

3. while

while statement

Example of usage:

    $var(i) = 0;
    while($var(i) < 10)
    {
        xlog("counter: $var(i)\n");
        $var(i) = $var(i) + 1;
    }

4.  Script Operations

Assignments plus string and arithmetic operations can be done directly in the configuration file.

5. Assignment

Assignments can be done like in C, via '=' (equal). The following pseudo-variables can be used in left side of an assignment:

• AVPs - to set the value of an AVP
• script variables ($var(...)) - to set the value of a script variable
• shared variables ($shv(...))
• $ru - to set R-URI
• $rd - to set domain part of R-URI
• $rU - to set user part of R-URI
• $rp - to set the port of R-URI
• $du - to set dst URI
• $fs - to set send socket
• $br - to set branch
• $mf - to set message flags value
• $sf - to set script flags value
• $bf - to set branch flags value

$var(a) = 123;

There is a special assign operator ':=' (colon equal) that can be used with AVPs. If the right value is 'null', all AVPs with that name are deleted. If different, the new value will overwrite any existing values for the AVPs with than name (on other words, delete existing AVPs with same name, add a new one with the right side value).

$avp(i:3) := 123;

6. String operations

For strings, '+' is available to concatenate.

$var(a) = "test";
$var(b) = "sip:" + $var(a) + "@" + $fd;

7. Arithmetic and bitwise operations

For numbers, one can use:

• + : plus
• - : minus
• / : divide
• * : multiply
• % : modulo
• | : bitwise OR
• & : bitwise AND
• ^ : bitwise XOR
• ~ : bitwise NOT
• << : bitwise left shift
• >> : bitwise right shift

Example:

$var(a) = 4 + ( 7 & ( ~2 ) );

NOTE: to ensure the priority of operands in expression evaluations do use __parenthesis__.

Arithmetic expressions can be used in condition expressions via test operator ' [ ... ] '.

if( [ $var(a) & 4 ] )
    log("var a has third bit set\n");