modify SIP contact header param

 
 when SIP_RESPONSE { 
  
     Check for 302 responses 
    if {[SIP::response code] == 302}{ 
  
        Parse the Contact header value "16601003" using scan 
        http://www.tcl.tk/man/tcl8.4/TclCmd/scan.htm 
          start reading everything not a @ into 'a' 
          then read everything not a : into 'b' 
          finally read the rest into 'c' 
        Example using tclsh: 
          % scan {"16601003"} {%[^@]@%[^:]:%s} a b c 
          3 
          % puts "$a $b $c" 
          "16601003" 
       if {[scan [SIP::header value "Contact"] {%[^@]@%[^:]:%s} a b c] == 3}{ 
  
           We parsed three strings into a b c 
          log local0. "Parsed [SIP::header value "Contact"] into $a, $b, $c" 
  
           Remove existing Contact header 
          SIP::header remove "Contact" 
  
           Insert new Contact header with 1.1.1.1 set as a static IP address 
          SIP::header insert "Contact" "${a}@1.1.1.1:${c}" 
  
          log local0. "Inserting new Contact header: ${a}@1.1.1.1:${c}" 
       } 
    } 
 }