Difference between revisions of "LSL Protocol/Restrained Love Relay/Reference Implementation"

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(Move change log to Change History)
(Version 1.015)
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* Chorazin Allen for reviewing the code, giving ideas, coding and re-coding his own scripts to make sure everything works properly between the relay and the cage, and for not killing me every time I change my mind here and there on the spec.
* Chorazin Allen for reviewing the code, giving ideas, coding and re-coding his own scripts to make sure everything works properly between the relay and the cage, and for not killing me every time I change my mind here and there on the spec.
 
* Azoth Amat and Nano Siemens for helping to find a solution to the "force sit on login" problem
* Gregor Mougin for discovering and fixing the not-pong reply on login.


==Reference Implementation==
==Reference Implementation==
Line 39: Line 40:


<lsl>
<lsl>
//~ RestrainedLife Viewer Relay Script example code
//~ RestrainedLife Viewer Relay Script example code
//~ By Marine Kelley
//~ By Marine Kelley, Maike Short, Felis Darwin
//~ 2008-02-03
//~ Thanks to Chorazin Allen, Azoth Amat, Gregor Mougin, Nano Siemens, Cerdita Piek
//~ v1.1
//~ 2008-02-16 with fixes by Maike Short
//~ 2008-02-24 more fixes by Maike Short
//~ 2008-03-03 code cleanup by Maike Short
//~ 2008-03-05 silently ignore commands for removing restrictions if they are not active anyway
//~ 2008-06-24 fix of loophole in ask-mode by Felis Darwin


//~ This code is provided AS-IS, OPEN-SOURCE and holds NO WARRANTY of accuracy,
//~ This code is provided AS-IS, OPEN-SOURCE and holds NO WARRANTY of accuracy,
//~ completeness or performance. It may only be distributed in its full source code,
//~ completeness or performance. It may only be distributed in its full source code,
//~ this header and disclaimer and is not to be sold.
//~ this header and disclaimer and is not to be sold.
//~ * Possible improvements
//~ Do some error checking
//~ Handle more than one object
//~ Periodically check that the in-world objects are still around, when one is missing purge its restrictions
//~ Manage an access list
//~ Reject some commands if not on access list (force remove clothes, force remove attachments...)
//~ and much more...


integer DEBUG = FALSE;
// make cheating (adding exceptions) a bit more difficult by not allowing
// attachment to control the viewer as they are not subjected to land building
// restrictions
integer ALLOW_CONTROL_BY_ATTACHMENTS = FALSE;
// list of refused commands. Use [] to allow everything or
// ["@detach", "@remoutfit"] to prevent striping for example
list refusedForceCommands = [];


// ---------------------------------------------------
// ---------------------------------------------------
Line 67: Line 64:
// ---------------------------------------------------
// ---------------------------------------------------
   
   
integer RLVRS_PROTOCOL_VERSION = 1014; // version of the protocol, stated on the specification page
integer RLVRS_PROTOCOL_VERSION = 1015; // version of the protocol, stated on the specification page
string RLVRS_IMPL_VERSION = "MSM Restraints 1.015.a"; // version of the implementation for debugging
   
   
string PREFIX_RL_COMMAND = "@";
string PREFIX_RL_COMMAND = "@";
Line 74: Line 72:
integer RLVRS_CHANNEL = -1812221819;  // RLVRS in numbers
integer RLVRS_CHANNEL = -1812221819;  // RLVRS in numbers
integer DIALOG_CHANNEL = -1812220409; // RLVDI in numbers
integer DIALOG_CHANNEL = -1812220409; // RLVDI in numbers
integer STATUS_LINK_CHANNEL = -1373421300;
integer RLV_LINK_CHANNEL = -1373421301;
integer CMD_LINK_CHANNEL = -1373421302;
integer DIALOG_LINK_CHANNEL = -1373421303;
integer ASK_LINK_CHANNEL = -1373421304;


integer MAX_OBJECT_DISTANCE = 20;    // 20m is llSay distance
integer MAX_OBJECT_DISTANCE = 20;    // 20m is llSay distance
integer MAX_TIME_AUTOACCEPT_AFTER_FORCESIT = 300; // 300 is 5 minutes
integer MAX_TIME_AUTOACCEPT_AFTER_FORCESIT = 60; // seconds


integer PERMISSION_DIALOG_TIMEOUT = 30;
integer PERMISSION_DIALOG_TIMEOUT = 30;
integer LOGIN_DELAY_WAIT_FOR_PONG = 10;
integer LOGIN_DELAY_WAIT_FOR_PONG = 10;
integer LOGIN_DELAY_WAIT_FOR_FORCE_SIT = 60;
integer LOGIN_DELAY_WAIT_FOR_FORCE_SIT = 60;
Line 86: Line 88:
integer MODE_ASK = 1;
integer MODE_ASK = 1;
integer MODE_AUTO = 2;
integer MODE_AUTO = 2;
list MODE_DESCRIPTIONS = ["RLV Relay is OFF", "RLV Relay is ON (permission needed)", "RLV Relay is ON (auto-accept)"];
string RVL_COMMAND_START = "@detach=n";
string RVL_COMMAND_END = "@detach=y";




Line 92: Line 99:
// ---------------------------------------------------
// ---------------------------------------------------
   
   
integer nMode;
integer mode;


list lRestrictions; // restrictions currently applied (without the "=n" part)
list restrictions; // restrictions currently applied (without the "=n" part)
key kSource;        // UUID of the object I'm commanded by, always equal to NULL_KEY if lRestrictions is empty, always set if not
key source;        // UUID of the object I'm commanded by, always equal to NULL_KEY if restrictions is empty, always set if not


string sPendingName; // name of initiator of pending request (first request of a session in mode 1)
string pendingName; // name of initiator of pending request (first request of a session in mode 1)
key sPendingId;      // UUID of initiator of pending request (first request of a session in mode 1)
key pendingId;      // UUID of initiator of pending request (first request of a session in mode 1)
string sPendingMessage; // message of pending request (first request of a session in mode 1)
string pendingMessage; // message of pending request
integer sPendingTime;
integer pendingTime;


// used on login
// used on login
Line 109: Line 116:
key    lastForceSitDestination;
key    lastForceSitDestination;
integer lastForceSitTime;
integer lastForceSitTime;
integer isNotEmbedded = TRUE;


// ---------------------------------------------------
// ---------------------------------------------------
//              Low Level Communication
//              Helper functions
// ---------------------------------------------------
// ---------------------------------------------------
 


debug(string x)
debug(string x)
{
{
//    llOwnerSay("DEBUG: " + x);
    if (DEBUG)
    {
        llOwnerSay("DEBUG: " + x);
    }
}
 
// checks whether this object is an attachment of an avatar
integer isAttachment(key id)
{
    vector objpos1 = llList2Vector(llGetObjectDetails(id, [OBJECT_POS]), 0);
    vector ownerpos = llList2Vector(llGetObjectDetails(llGetOwnerKey(id), [OBJECT_POS]), 0);
    vector objpos2 = llList2Vector(llGetObjectDetails(id, [OBJECT_POS]), 0);
    return (llVecMag(objpos1 - ownerpos) <= llVecMag(objpos1 - objpos2));
}
}
// ---------------------------------------------------
//              Low Level Communication
// ---------------------------------------------------
   
   
// acknowledge or reject
// acknowledge or reject
Line 129: Line 156:
sendRLCmd(string cmd)
sendRLCmd(string cmd)
{
{
     llOwnerSay(cmd);
     if (cmd != "")
    {
        if (isNotEmbedded)
        {
            llOwnerSay(cmd);
        }
        llMessageLinked(LINK_SET, RLV_LINK_CHANNEL, cmd, source);
    }
}
}


// get current mode as string
string getModeDescription()
{
    if (nMode == 0) return "RLV Relay is OFF";
    else if (nMode == 1) return "RLV Relay is ON (permission needed)";
    else return "RLV Relay is ON (auto-accept)";
}


// check that this command is for us and not someone else
// check that this command is for us and not someone else
Line 144: Line 171:
{
{
     list tokens = llParseString2List(message, [","], []);
     list tokens = llParseString2List(message, [","], []);
     if (llGetListLength(tokens) == 3) // this is a normal command
     if (llGetListLength(tokens) != 3) // this is not a normal command
    {
        return FALSE;
    }
 
    return (llList2String(tokens, 1) == llGetOwner()); // talking to me ?
}
 
// checks that the type of object (world object, attachment) is allowed
integer verifySourceType(key id)
{
    if (ALLOW_CONTROL_BY_ATTACHMENTS)
     {
     {
      if (llList2String(tokens, 1) == llGetOwner()) // talking to me ?
        return TRUE;
      {
        return TRUE;
      }
     }
     }
     return FALSE;
   
     return !isAttachment(id);
}
}


Line 157: Line 193:
//              Permission Handling
//              Permission Handling
// ---------------------------------------------------
// ---------------------------------------------------


// are we already under command by this object?
// are we already under command by this object?
integer isObjectKnow(key id)
integer isObjectKnow(key id)
{
{
    // first some error handling
    if (id == NULL_KEY)
    {
        return FALSE;
    }
     // are we already under command by this object?
     // are we already under command by this object?
     if (kSource == id)
     if (source == id)
     {
     {
         return TRUE;
         return TRUE;
Line 174: Line 205:


     // are we not under command by any object but were we forced to sit on this object recently?
     // are we not under command by any object but were we forced to sit on this object recently?
     if ((kSource == NULL_KEY) && (id == lastForceSitDestination))
     if ((source == NULL_KEY) && (id == lastForceSitDestination))
     {
     {
         debug("on last force sit target");
         debug("on last force sit target");
Line 243: Line 274:
}
}


// is this a simple atmar command
// is this a simple atomar command
// (a command which only queries some information or releases restrictions)
// (a command which only queries some information or releases restrictions)
// (e. g.: cmd ends with "=" and a number (@version, @getoutfit, @getattach) or is a !-meta-command)
// (e. g.: cmd ends with "=" and a number (@version, @getoutfit, @getattach) or is a !-meta-command)
Line 293: Line 324:
integer tryToGluePendingCommands(key id, string commands)
integer tryToGluePendingCommands(key id, string commands)
{
{
     if ((sPendingId == id) && (sPendingTime + PERMISSION_DIALOG_TIMEOUT > llGetUnixTime()))
     if (llStringLength(pendingMessage) > 4000)
    {
        llSay(0, llKey2Name(id) + " is flooding commands. Releasing restrictions.");
        releaseRestrictions();
        return TRUE;
    }
    if ((pendingId == id) && (pendingTime + PERMISSION_DIALOG_TIMEOUT > llGetUnixTime()))
     {
     {
         debug("Gluing " + sPendingMessage + " with " + commands);
         debug("Gluing " + (string) pendingMessage + " with " + commands);
         sPendingMessage = sPendingMessage + "|" + commands;
         pendingMessage = pendingMessage + "|" + commands;
         return TRUE;
         return TRUE;
     }
     }
     return FALSE;
     return FALSE;
}
}
// accept !release even if out of range
handleCommandsWhichAreAcceptedOutOfRange(key id, string message)
{
    if (id != source)
    {
        return;
    }
    list tokens = llParseString2List (message, [","], []);
    if (llGetListLength (tokens) < 3)
    {
        return;
    }
    string commands = llList2String(tokens, 2);
    list list_of_commands = llParseString2List(commands, ["|"], []);
    if (llListFindList(list_of_commands, ["!release"]) > -1)
    {
        debug("accepted !release although it was out of range");
        releaseRestrictions();
    }
}


// verifies the permission. This includes mode  
// verifies the permission. This includes mode  
Line 308: Line 369:
{
{
     // is it switched off?
     // is it switched off?
     if (nMode == MODE_OFF)
     if (mode == MODE_OFF)
     {
     {
         return FALSE;
         return FALSE;
     }
     }


    // extract the commands-part
     list tokens = llParseString2List (message, [","], []);
     list tokens = llParseString2List (message, [","], []);
     if (llGetListLength (tokens) < 3)
     if (llGetListLength (tokens) < 3)
Line 321: Line 381:
     string commands = llList2String(tokens, 2);
     string commands = llList2String(tokens, 2);
     list list_of_commands = llParseString2List(commands, ["|"], []);
     list list_of_commands = llParseString2List(commands, ["|"], []);
    // accept harmless commands silently
    if (isSimpleRequest(list_of_commands))
    {
        return TRUE;
    }


     // if we are already having a pending permission-dialog request for THIS object,
     // if we are already having a pending permission-dialog request for THIS object,
Line 333: Line 387:
     {
     {
         return FALSE;
         return FALSE;
    }
    // accept harmless commands silently
    if (isSimpleRequest(list_of_commands))
    {
        return TRUE;
     }
     }


Line 344: Line 404:


     // ask in permission-request-mode and/OR in case the object identity is suspisous.
     // ask in permission-request-mode and/OR in case the object identity is suspisous.
     if (nMode == MODE_ASK || !trustworthy)
     if (mode == MODE_ASK || !trustworthy)
     {
     {
         sPendingId=id;
         pendingId=id;
         sPendingName=name;
         pendingName=name;
         sPendingMessage=message;
         pendingMessage = message;
         sPendingTime = llGetUnixTime();
         pendingTime = llGetUnixTime();
         llDialog (llGetOwner(), name + " would like control your viewer." + warning + ".\n\nDo you accept ?", ["Yes", "No"], DIALOG_CHANNEL);
         if (llKey2Name(llGetOwnerKey(id)) != "")
        {
            name += " (owned by " + llKey2Name(llGetOwnerKey(id)) + ")";
        }
       
        string text = name + " would like control your viewer." + warning + ".\n\nDo you accept ?";
        debug("Asking for permission isNotEmbedded=" + (string) isNotEmbedded);
        if (isNotEmbedded)
        {
            llDialog (llGetOwner(), text, ["Yes", "No"], DIALOG_CHANNEL);
        }
        llMessageLinked(LINK_SET, ASK_LINK_CHANNEL, text, id);
         debug("Asking for permission");
         debug("Asking for permission");
         return FALSE;
         return FALSE;
Line 367: Line 438:
execute(string name, key id, string message)
execute(string name, key id, string message)
{
{
     list tokens=llParseString2List (message, [","], []);
     list tokens = llParseString2List(message, [","], []);
     if (llGetListLength (tokens)==3) // this is a normal command
     string cmd_id = llList2String(tokens, 0); // CheckAttach
    list list_of_commands = llParseString2List(llList2String(tokens, 2), ["|"], []);
 
    integer len = llGetListLength (list_of_commands);
    integer i;
    string command;
    string prefix;
    for (i=0; i<len; ++i) // execute every command one by one
     {
     {
         string cmd_id=llList2String (tokens, 0); // CheckAttach
         // a command is a RL command if it starts with '@' or a metacommand if it starts with '!'
         key target=llList2Key (tokens, 1); // UUID
        command = llList2String(list_of_commands, i);
         if (target==llGetOwner ()) // talking to me ?
         prefix = llGetSubString(command, 0, 0);
 
         if (prefix == PREFIX_RL_COMMAND) // this is a RLV command
         {
         {
             list list_of_commands=llParseString2List (llList2String (tokens, 2), ["|"], []);
             executeRLVCommand(cmd_id, id, command);
            integer len=llGetListLength (list_of_commands);
        }
            integer i;
        else if (prefix == PREFIX_METACOMMAND) // this is a metacommand, aimed at the relay itself
            string command;
        {
            string prefix;
            executeMetaCommand(cmd_id, id, command);
            for (i=0; i<len; ++i) // execute every command one by one
            {
                // a command is a RL command if it starts with '@' or a metacommand if it starts with '!'
                command=llList2String (list_of_commands, i);
                prefix=llGetSubString (command, 0, 0);
                if (prefix==PREFIX_RL_COMMAND) // this is a RL command
                {
                    executeRLVCommand(cmd_id, id, command);
                }
                else if (prefix==PREFIX_METACOMMAND) // this is a metacommand, aimed at the relay itself
                {
                    executeMetaCommand(cmd_id, id, command);
                }
            }
         }
         }
     }
     }
Line 402: Line 467:
executeRLVCommand(string cmd_id, string id, string command)
executeRLVCommand(string cmd_id, string id, string command)
{
{
    command = llToLower(command);
     // we need to know whether whether is a rule or a simple command
     // we need to know whether whether is a rule or a simple command
     list tokens_command=llParseString2List (command, ["="], []);
     list tokens = llParseString2List(command, ["="], []);
     string behav=llList2String (tokens_command, 0); // @getattach:skull
     string behav = llList2String(tokens, 0); // @getattach:skull
     string param=llList2String (tokens_command, 1); // 2222
     string param = llList2String(tokens, 1); // 2222
     integer ind=llListFindList (lRestrictions, [behav]);
     integer ind = llListFindList(restrictions, [behav]);


     if (param=="n" || param=="add") // add to lRestrictions
    tokens = llParseString2List(behav, [":"], []); // @sit:<uuid>
    string behavName = llList2String (tokens, 0);  // @sit
    string option = llList2String (tokens, 1);    // <uuid>
   
    debug("executeRLVCommand: behav=!" + behav + "! param=!" + param + "!");
 
     if (param=="n" || param=="add") // add to restrictions
    {
        if (ind < 0)
        {
            if (llGetListLength(restrictions) == 0)
            {
                sendRLCmd(RVL_COMMAND_START);
                llMessageLinked(LINK_SET, STATUS_LINK_CHANNEL, "start", id);
            }
            restrictions += [behav];
        }
        source = id; // we know that source is either NULL_KEY or id already
    }
    else if (param == "y" || param == "rem") // remove from restrictions
     {
     {
         if (ind<0) lRestrictions+=[behav];
         if (ind > -1)
         kSource=id; // we know that kSource is either NULL_KEY or id already
        {
            restrictions = llDeleteSubList (restrictions, ind, ind);
        }
        if (llGetListLength(restrictions) == 0)
        {
            source = NULL_KEY;
            sendRLCmd(RVL_COMMAND_END);
         }
        removeFromPendingList(behav);
     }
     }
     else if (param=="y" || param=="rem") // remove from lRestrictions
     else if (param == "force")
     {
     {
         if (ind > -1) lRestrictions=llDeleteSubList (lRestrictions, ind, ind);
         if (llListFindList(refusedForceCommands, [behavName]) >= 0)
         if (llGetListLength (lRestrictions)==0) kSource=NULL_KEY;
        {
            debug("rejected force-command: behav=!" + behav + "! behavName=!" + behavName + "!");
            ack(cmd_id, id, command, "ko");
            return;
         }
     }
     }


     workaroundForAtClear(command);
     workaroundForAtClear(command);
     rememberForceSit(command);
     rememberForceSit(behavName, option, param);
     sendRLCmd(command); // execute command
     sendRLCmd(command); // execute command
     ack(cmd_id, id, command, "ok"); // acknowledge
     ack(cmd_id, id, command, "ok"); // acknowledge
Line 439: Line 536:


// remembers the time and object if this command is a force sit
// remembers the time and object if this command is a force sit
rememberForceSit(string command)
rememberForceSit(string behavName, string option, string param)
{
{
     list tokens_command=llParseString2List (command, ["="], []);
     // clear lastForceSitDestination in case we are now prevented from standing up and
    string behav=llList2String (tokens_command, 0); // @sit:<uuid>
    // the force sit was long ago. Note: restrictions is checked to prevent the
    string param=llList2String (tokens_command, 1); // force
    // clearance in case @unsit is just send again on login
    if (behavName == "@unsit")
    {
        if (llListFindList(restrictions, ["@unsit"]) < 0)
        {
            if (lastForceSitTime + MAX_TIME_AUTOACCEPT_AFTER_FORCESIT < llGetUnixTime())
            {
                debug("clearing lastForceSitDestination");
                lastForceSitDestination = NULL_KEY;
            }
        }
    }
   
     if (param != "force")
     if (param != "force")
     {
     {
Line 449: Line 558:
     }
     }


    tokens_command=llParseString2List(behav, [":"], []);
     debug("'force'-command:" + behavName + "/" + option);
    behav=llList2String (tokens_command, 0); // @sit
     if (behavName != "@sit")
    param=llList2String (tokens_command, 1); // <uuid>
     debug("'force'-command:" + behav + "/" + param);
     if (behav != "@sit")
     {
     {
         return;
         return;
     }
     }
     lastForceSitDestination = (key) param;
     lastForceSitDestination = (key) option;
     lastForceSitTime = llGetUnixTime();
     lastForceSitTime = llGetUnixTime();
     debug("remembered force sit");
     debug("remembered force sit");
Line 465: Line 571:
executeMetaCommand(string cmd_id, string id, string command)
executeMetaCommand(string cmd_id, string id, string command)
{
{
     if (command==PREFIX_METACOMMAND+"version") // checking relay version
     if (command == PREFIX_METACOMMAND + "version") // checking relay protocol version
    {
        ack(cmd_id, id, command, (string) RLVRS_PROTOCOL_VERSION);
    }
    else if (command == PREFIX_METACOMMAND + "implversion") // checking relay version
     {
     {
         ack(cmd_id, id, command, (string)RLVRS_PROTOCOL_VERSION);
         ack(cmd_id, id, command, RLVRS_IMPL_VERSION);
     }
     }
     else if (command==PREFIX_METACOMMAND+"release") // release all the restrictions (end session)
     else if (command == PREFIX_METACOMMAND + "release") // release all the restrictions (end session)
     {
     {
         releaseRestrictions();
         releaseRestrictions();
         ack(cmd_id, id, command, "ok");
         ack(cmd_id, id, command, "ok");
     }
     }
    else if (command == PREFIX_METACOMMAND + "pong")
    {
        loginWaitingForPong = FALSE;
    }
}
// removes a restriction from the list of pending commands
removeFromPendingList(string behav)
{
    string search = behav + "=";
    // don't do the expensive parsing (string operations are very slow in pre-
    // mono LSL) in case we can detect fast that this one is not in the list.
    if (llSubStringIndex(pendingMessage, search) < 0)
    {
        return;
    }
    list tokens = llParseString2List(pendingMessage, [","], []);
    list commands = llParseString2List(llList2String(tokens, 2), ["|"], []);
    integer modified = FALSE;
    integer len = llGetListLength(commands);
    integer i;
    for (i = len - 1; i >= 0; i--)
    {
        string cmd = llList2String(commands, i);
        if (llSubStringIndex(cmd, search) == 0)
        {
            if (llSubStringIndex(cmd, "=n") > -1 || llSubStringIndex(cmd, "=add") > -1)
            {
                commands = llDeleteSubList(commands, i, i);
                modified = TRUE;
            }
        }
    }
    if (modified)
    {
        if (llGetListLength(commands) > 0)
        {
            pendingMessage = llList2String(tokens, 0) + "," + llList2String(tokens, 1) + "," + llDumpList2String(commands, "|");
        }
        else
        {
            clearPendingMessages();
        }
    }
}
}
   
   
// lift all the restrictions (called by !release and by turning the relay off)
// lift all the restrictions (called by !release and by turning the relay off)
releaseRestrictions ()
releaseRestrictions()
{
{
     kSource=NULL_KEY;
     source = NULL_KEY;
     integer i;
     integer i;
     integer len=llGetListLength (lRestrictions);
     integer len = llGetListLength (restrictions);
     for (i=0; i<len; ++i)
     for (i = 0; i < len; ++i)
     {
     {
         sendRLCmd(llList2String (lRestrictions, i)+"=y");
         sendRLCmd(llList2String (restrictions, i) + "=y");
     }
     }
     lRestrictions = [];
     sendRLCmd(RVL_COMMAND_END);
    lastForceSitDestination = NULL_KEY;
    restrictions = [];
     loginPendingForceSit = FALSE;
     loginPendingForceSit = FALSE;
    clearPendingMessages();
    llMessageLinked(LINK_SET, STATUS_LINK_CHANNEL, "release", NULL_KEY);
}
// deletes the list of pending messsages
clearPendingMessages()
{
    // clear pending request
    pendingName = "";
    pendingId = NULL_KEY;
    pendingMessage = "";
    pendingTime = 0;
}
// processes a message send on the relay channel
processRelayMessage(string name, key id, string message)
{
    if (mode== MODE_OFF)
    {
        debug("deactivated - ignoring commands");
        return; // mode is 0 (off) => reject
    }
    debug("LISTEN: " + message);
    if (!verifyWeAreTarget(message))
    {
      return;
    }
    if (!verifySourceType(id))
    {
        return;
    }
    debug("Got message (active world object " + (string) source + "): name=" + name+ " id=" + (string) id + " message=" + message);
    if (source)
    {
        if (source != id)
        {
            if (isObjectNear(source))
            {
                debug("already used by another object => reject");
                return;
            }
            else
            {
                debug("already used by another object, which is out of range");
                releaseRestrictions();
            }
        }
    }
    if (!isObjectNear(id))
    {
        handleCommandsWhichAreAcceptedOutOfRange(id, message);
        return;
    }
    if (!isObjectKnow(id))
    {
        debug("asking for permission because source is NULL_KEY");
        if (!verifyPermission(id, name, message))
        {
            return;
        }
    }
    debug("Executing: " + (string) source);
    execute(name, id, message);
}
}
// ---------------------------------------------------
//            mode and dialog handling
// ---------------------------------------------------
// shows current mode as string
showModeDescription()
{
    if (isNotEmbedded)
    {
        llOwnerSay(llList2String(MODE_DESCRIPTIONS, mode));
    }
    llMessageLinked(LINK_SET, STATUS_LINK_CHANNEL, "show_mode", (key) ((string) mode));
}
// process the Yes/No buttons of the permission dialog
processDialogResponse(key id, string message)
{
    if (pendingId)
    {
        if (message == "Yes") // pending request authorized => process it
        {
            execute(pendingName, pendingId, pendingMessage);
        }
        clearPendingMessages();
    }
}


   
   
Line 496: Line 762:
   
   
init() {
init() {
     nMode=1;
     sendRLCmd("@clear");
     kSource=NULL_KEY;
     llOwnerSay("Waiting for plugins to initialize...");
     lRestrictions=[];
     llSleep(5);
    sPendingId=NULL_KEY;
 
     sPendingName="";
     mode = MODE_ASK;
    sPendingMessage="";
 
     llListen (RLVRS_CHANNEL, "", "", "");
     llListen(RLVRS_CHANNEL, "", "", "");
     llListen (DIALOG_CHANNEL, "", llGetOwner(), "");
     llListen(DIALOG_CHANNEL, "", llGetOwner(), "");
     llOwnerSay (getModeDescription());
 
    if (llGetFreeMemory() < 10000)
    {
        llSay(0, llKey2Name(llGetOwner()) + ", your relay is having very little free script memory and is likly to crash during use. Please verify that it was compiled using Mono.");
    }
    llMessageLinked(LINK_SET, STATUS_LINK_CHANNEL, "init", NULL_KEY);
 
     llOwnerSay("Initialized and ready");
    showModeDescription();
    debug("Free Memory: " + (string) llGetFreeMemory());
}
}


// sends the known restrictions (again) to the RL-viewer
// sends the known restrictions (again) to the RL-viewer
Line 512: Line 788:
{
{
     integer i;
     integer i;
     integer len=llGetListLength(lRestrictions);
     integer len = llGetListLength(restrictions);
     string restr;
     string restr;
     debug("kSource=" + (string) kSource);
     debug("source=" + (string) source);
     for (i=0; i<len; ++i)
     if (len > 0)
     {
     {
         restr=llList2String(lRestrictions, i);
        sendRLCmd(RVL_COMMAND_START);
    }
    for (i=0; i < len; ++i)
    {
         restr = llList2String(restrictions, i);
         debug("restr=" + restr);
         debug("restr=" + restr);
         sendRLCmd(restr+"=n");
         sendRLCmd(restr + "=n");
         if (restr=="@unsit")
         if (restr == "@unsit")
         {
         {
             loginPendingForceSit = TRUE;
             loginPendingForceSit = TRUE;
Line 531: Line 811:
{
{
     loginWaitingForPong = FALSE;
     loginWaitingForPong = FALSE;
     if (kSource != NULL_KEY)
     if (source)
     {
     {
         ack("ping", kSource, "ping", "ping");
         ack("ping", source, "ping", "ping");
         timerTickCounter = 0;
         timerTickCounter = 0;
         llSetTimerEvent(1.0);
         llSetTimerEvent(1.0);
Line 539: Line 819:
     }
     }
}
}
sendForceSitDuringLogin()
{
    key sitTarget = source;
    if (lastForceSitDestination)
    {
        sitTarget = lastForceSitDestination;
    }
    debug("Force sit during login on " + (string) sitTarget + " (source=" + (string) source + ", lastForceSitDestination=" + (string) lastForceSitDestination + ")");
    sendRLCmd ("@sit:" + (string) sitTarget + "=force");
}
// processes a timer event
processTimer()
{
    timerTickCounter++;
    debug("timer (" + (string) timerTickCounter + "): waiting for pong: " + (string) loginWaitingForPong + " pendingForceSit: " + (string) loginPendingForceSit);
    if (loginWaitingForPong && (timerTickCounter >= LOGIN_DELAY_WAIT_FOR_PONG))
    {
        llWhisper(0, "Lucky Day: " + llKey2Name(llGetOwner()) + " is freed because the device is not available.");
        loginWaitingForPong = FALSE;
        loginPendingForceSit = FALSE;
        releaseRestrictions();
    }
    if (loginPendingForceSit)
    {
        integer agentInfo = llGetAgentInfo(llGetOwner());
        if (agentInfo & AGENT_SITTING)
        {
            loginPendingForceSit = FALSE;
            debug("is sitting now");
        }
        else if (timerTickCounter == LOGIN_DELAY_WAIT_FOR_FORCE_SIT)
        {
            llWhisper(0, "Lucky Day: " + llKey2Name(llGetOwner()) + " is freed because sitting down again was not possible.");
            loginPendingForceSit = FALSE;
            releaseRestrictions();
        }
        else
        {
            sendForceSitDuringLogin();
        }
    }
    if (!loginPendingForceSit && !loginWaitingForPong)
    {
        llSetTimerEvent(0.0);
    }
}
processLinkMessage(key id, string message)
{
    if (message == "safeword")
    {
        llSay(0, llKey2Name(llGetOwner()) + " said the safeword. Freeing and deactivating relay.");
        releaseRestrictions();
        mode = MODE_OFF;
        showModeDescription();
        return;
    }
    if (message == "unlock")
    {
        if (id)
        {
            llSay(0, llKey2Name(id) + " freed " + llKey2Name(llGetOwner()) + " by unlocking the relay.");
        }
        releaseRestrictions();
        return;
    }
    if (message == "mode")
    {
        if (source)
        {
            llOwnerSay("Sorry, you cannot change the relay mode while it is active.");
            return;
        }
        mode = ((integer) ((string) id)) % 3;   
        showModeDescription();
        return;
    }
    if (message == "refusedForceCommands")
    {
        refusedForceCommands = llParseString2List((string) id, [","], []);
        return;
    }
    if (message == "embedded")
    {
        isNotEmbedded = FALSE;
        return;
    }
}


default
default
Line 551: Line 929:
         // relogging, we must refresh the viewer and ping the object if any
         // relogging, we must refresh the viewer and ping the object if any
         // if mode is not OFF, fire all the stored restrictions
         // if mode is not OFF, fire all the stored restrictions
         if (nMode)
         if (mode)
         {
         {
             reinforceKnownRestrictions();
             reinforceKnownRestrictions();
Line 557: Line 935:
         }
         }
         // remind the current mode to the user
         // remind the current mode to the user
         llOwnerSay(getModeDescription());
         showModeDescription();
     }
     }


     timer()
     timer()
     {
     {
         timerTickCounter++;
         processTimer();
        debug("timer (" + (string) timerTickCounter + "): waiting for pong: " + (string) loginWaitingForPong + " pendingForceSit: " + (string) loginPendingForceSit);
    }
        if (loginWaitingForPong && (timerTickCounter == LOGIN_DELAY_WAIT_FOR_PONG))
        {
            llWhisper(0, "Lucky Day: " + llKey2Name(llGetOwner()) + " is freed because the device is not available.");
            loginWaitingForPong = FALSE;
            loginPendingForceSit = FALSE;
            releaseRestrictions();
        }


         if (loginPendingForceSit)
    listen(integer channel, string name, key id, string message)
    {
         if (channel==RLVRS_CHANNEL)
         {
         {
             integer agentInfo = llGetAgentInfo(llGetOwner());
             processRelayMessage(name, id, message);
            if (agentInfo & AGENT_SITTING)
            {
                loginPendingForceSit = FALSE;
                debug("is sitting now");
            }
            else if (timerTickCounter == LOGIN_DELAY_WAIT_FOR_FORCE_SIT)
            {
                llWhisper(0, "Lucky Day: " + llKey2Name(llGetOwner()) + " is freed because sitting down again was not possible.");
                loginPendingForceSit = FALSE;
                releaseRestrictions();
            }
            else
            {
                sendRLCmd ("@sit:"+(string)kSource+"=force");
            }
         }
         }
 
         else if (channel==DIALOG_CHANNEL)
         if (!loginPendingForceSit && !loginWaitingForPong)
         {
         {
             llSetTimerEvent(0.0);
             processDialogResponse(id, message);
         }
         }
     }
     }
   
     listen(integer channel, string name, key id, string message)
     link_message(integer sender, integer channel, string message, key id)
     {
     {
         if (channel==RLVRS_CHANNEL)
         if (channel == CMD_LINK_CHANNEL)
         {
         {
             if (!verifyWeAreTarget(message))
             processLinkMessage(id, message);
            {
              return;
            }
       
            if (nMode== MODE_OFF)
            {
                debug("deactivated - ignoring commands");
                return; // mode is 0 (off) => reject
            }
            if (!isObjectNear(id)) return;
 
            debug("Got message (active world object " + (string) kSource + "): name=" + name+ "id=" + (string) id + " message=" + message);
            if (kSource != NULL_KEY && kSource != id)
            {
                debug("already used by another object => reject");
                return;
            }
 
            loginWaitingForPong = FALSE; // whatever the message, it is for me => it satisfies the ping request
 
            if (!isObjectKnow(id))
            {
                debug("asking for permission because kSource is NULL_KEY");
                if (!verifyPermission(id, name, message))
                {
                    return;
                }
            }
 
            debug("Executing: " + (string) kSource);
            execute(name, id, message);
         }
         }
         else if (channel==DIALOG_CHANNEL)
         else if (channel == DIALOG_LINK_CHANNEL)
         {
         {
             if (id != llGetOwner())
             processDialogResponse(id, message);
            {
                return; // only accept dialog responses from the owner
            }
            if (sPendingId!=NULL_KEY)
            {
                if (message=="Yes") // pending request authorized => process it
                {
                    execute(sPendingName, sPendingId, sPendingMessage);
                }
 
                // clear pending request
                sPendingName="";
                sPendingId=NULL_KEY;
                sPendingMessage="";
            }
         }
         }
     }
     }
 
     touch_start(integer num_detected)
     touch_start(integer num_detected)
     {
     {
        if (!isNotEmbedded)
        {
            return;
        }
         // touched by user => cycle through OFF/ON_PERMISSION/ON_ALWAYS modes
         // touched by user => cycle through OFF/ON_PERMISSION/ON_ALWAYS modes
         key toucher=llDetectedKey(0);
         key toucher = llDetectedKey(0);
         if (toucher==llGetOwner())
         if (toucher != llGetOwner())
         {
         {
             if (kSource != NULL_KEY)
             return;
            {
        }
                llOwnerSay("Sorry, you cannot change the relay mode while it is locked.");
 
                return;
        if (source)
            }
        {
            ++nMode;
            llOwnerSay("Sorry, you cannot change the relay mode while it is active.");
            if (nMode>2) nMode=0;
            return;
            if (nMode==MODE_OFF) releaseRestrictions ();
        }
             llOwnerSay (getModeDescription());
        mode = (mode + 1) % 3;
        if (mode == MODE_OFF) {
             releaseRestrictions();
         }
         }
        showModeDescription();
     }
     }


     changed(integer change)
     changed(integer change)
     {
     {
         if (change & CHANGED_OWNER)  
         if (change & (CHANGED_OWNER | CHANGED_INVENTORY | CHANGED_ALLOWED_DROP))  
         {
         {
             llResetScript();
             llResetScript();
Line 684: Line 1,001:
     }
     }
}
}
</lsl>
</lsl>

Revision as of 02:28, 30 August 2008

This particular example that anyone can distribute freely as open-source only (you are not allowed to sell this code) and including the header comments is just meant to give an idea of how a relay basically works. You can find the change history at Change History,


What it does

  • Implements the specification described hereabove.
  • Commented to facilitate reading and learning.
  • Tested and working with test objects and with real cages.


What it doesn't do

  • Error-checking.
  • Access lists.
  • Lock on the avatar.
  • Handle more than one object.
  • Reject some commands by nature.
  • And so much more that makes good scripts stand out in the crowd.


How to use it

  • Create a prim in which you put a script containing this code (don't forget to name it correctly by following the "RLVnnn" requirement).
  • Wear the prim, it says its current on/off status
  • Click on the prim to switch from "Off" to "On with permission" to "On without permission" and back to "Off"
  • Find an object that implements this specification and test.


Special thanks

  • Chorazin Allen for reviewing the code, giving ideas, coding and re-coding his own scripts to make sure everything works properly between the relay and the cage, and for not killing me every time I change my mind here and there on the spec.
  • Azoth Amat and Nano Siemens for helping to find a solution to the "force sit on login" problem
  • Gregor Mougin for discovering and fixing the not-pong reply on login.

Reference Implementation

Please add fixes, new features and stuff like that to Development & Contribution.

<lsl> //~ RestrainedLife Viewer Relay Script example code //~ By Marine Kelley, Maike Short, Felis Darwin //~ Thanks to Chorazin Allen, Azoth Amat, Gregor Mougin, Nano Siemens, Cerdita Piek

//~ This code is provided AS-IS, OPEN-SOURCE and holds NO WARRANTY of accuracy, //~ completeness or performance. It may only be distributed in its full source code, //~ this header and disclaimer and is not to be sold.

integer DEBUG = FALSE;

// make cheating (adding exceptions) a bit more difficult by not allowing // attachment to control the viewer as they are not subjected to land building // restrictions integer ALLOW_CONTROL_BY_ATTACHMENTS = FALSE;


// list of refused commands. Use [] to allow everything or // ["@detach", "@remoutfit"] to prevent striping for example list refusedForceCommands = [];

// --------------------------------------------------- // Constants // ---------------------------------------------------

integer RLVRS_PROTOCOL_VERSION = 1015; // version of the protocol, stated on the specification page string RLVRS_IMPL_VERSION = "MSM Restraints 1.015.a"; // version of the implementation for debugging

string PREFIX_RL_COMMAND = "@"; string PREFIX_METACOMMAND = "!";

integer RLVRS_CHANNEL = -1812221819; // RLVRS in numbers integer DIALOG_CHANNEL = -1812220409; // RLVDI in numbers integer STATUS_LINK_CHANNEL = -1373421300; integer RLV_LINK_CHANNEL = -1373421301; integer CMD_LINK_CHANNEL = -1373421302; integer DIALOG_LINK_CHANNEL = -1373421303; integer ASK_LINK_CHANNEL = -1373421304;

integer MAX_OBJECT_DISTANCE = 20; // 20m is llSay distance integer MAX_TIME_AUTOACCEPT_AFTER_FORCESIT = 60; // seconds

integer PERMISSION_DIALOG_TIMEOUT = 30; integer LOGIN_DELAY_WAIT_FOR_PONG = 10; integer LOGIN_DELAY_WAIT_FOR_FORCE_SIT = 60;

integer MODE_OFF = 0; integer MODE_ASK = 1; integer MODE_AUTO = 2;

list MODE_DESCRIPTIONS = ["RLV Relay is OFF", "RLV Relay is ON (permission needed)", "RLV Relay is ON (auto-accept)"];

string RVL_COMMAND_START = "@detach=n"; string RVL_COMMAND_END = "@detach=y";


// --------------------------------------------------- // Variables // ---------------------------------------------------

integer mode;

list restrictions; // restrictions currently applied (without the "=n" part) key source; // UUID of the object I'm commanded by, always equal to NULL_KEY if restrictions is empty, always set if not

string pendingName; // name of initiator of pending request (first request of a session in mode 1) key pendingId; // UUID of initiator of pending request (first request of a session in mode 1) string pendingMessage; // message of pending request integer pendingTime;

// used on login integer timerTickCounter; // count the number of time events on login (forceSit has to be delayed a bit) integer loginWaitingForPong; integer loginPendingForceSit;

key lastForceSitDestination; integer lastForceSitTime;

integer isNotEmbedded = TRUE;

// --------------------------------------------------- // Helper functions // ---------------------------------------------------


debug(string x) {

   if (DEBUG)
   {
       llOwnerSay("DEBUG: " + x);
   }

}

// checks whether this object is an attachment of an avatar integer isAttachment(key id) {

   vector objpos1 = llList2Vector(llGetObjectDetails(id, [OBJECT_POS]), 0);
   vector ownerpos = llList2Vector(llGetObjectDetails(llGetOwnerKey(id), [OBJECT_POS]), 0);
   vector objpos2 = llList2Vector(llGetObjectDetails(id, [OBJECT_POS]), 0);
   return (llVecMag(objpos1 - ownerpos) <= llVecMag(objpos1 - objpos2));

}


// --------------------------------------------------- // Low Level Communication // ---------------------------------------------------


// acknowledge or reject ack(string cmd_id, key id, string cmd, string ack) {

   llSay(RLVRS_CHANNEL, cmd_id + "," + (string)id + "," + cmd + "," + ack);

}

// cmd begins with a '@' sendRLCmd(string cmd) {

   if (cmd != "")
   {
       if (isNotEmbedded)
       {
           llOwnerSay(cmd);
       }
       llMessageLinked(LINK_SET, RLV_LINK_CHANNEL, cmd, source);
   }

}


// check that this command is for us and not someone else integer verifyWeAreTarget(string message) {

   list tokens = llParseString2List(message, [","], []);
   if (llGetListLength(tokens) != 3) // this is not a normal command
   {
       return FALSE;
   }
   return (llList2String(tokens, 1) == llGetOwner()); // talking to me ?

}

// checks that the type of object (world object, attachment) is allowed integer verifySourceType(key id) {

   if (ALLOW_CONTROL_BY_ATTACHMENTS)
   {
       return TRUE;
   }
   
   return !isAttachment(id);

}

// --------------------------------------------------- // Permission Handling // ---------------------------------------------------


// are we already under command by this object? integer isObjectKnow(key id) {

   // are we already under command by this object?
   if (source == id)
   {
       return TRUE;
   }
   // are we not under command by any object but were we forced to sit on this object recently?
   if ((source == NULL_KEY) && (id == lastForceSitDestination))
   {
       debug("on last force sit target");
       if (lastForceSitTime + MAX_TIME_AUTOACCEPT_AFTER_FORCESIT > llGetUnixTime())
       {
           debug("and recent enough to auto accept");
           return TRUE;
       }
   }
   return FALSE;

}


// check whether the object is in llSay distance. // The specification requires llSay instead of llShout or llRegionSay // to be used to limit the range. But this has to be checked here again // because the objects are not trustworthy. integer isObjectNear(key id) {

   vector myPosition = llGetRootPosition();
   list temp = llGetObjectDetails(id, ([OBJECT_POS]));
   vector objPostition = llList2Vector(temp,0);
   float distance = llVecDist(objPostition, myPosition);
   return distance <= MAX_OBJECT_DISTANCE;

}

// do a basic check on the identity of the object trying to issue a command integer isObjectIdentityTrustworthy(key id) {

   key parcel_owner=llList2Key (llGetParcelDetails (llGetPos (), [PARCEL_DETAILS_OWNER]), 0);
   key parcel_group=llList2Key (llGetParcelDetails (llGetPos (), [PARCEL_DETAILS_GROUP]), 0);
   key object_owner=llGetOwnerKey(id);
   key object_group=llList2Key (llGetObjectDetails (id, [OBJECT_GROUP]), 0);
   debug("owner= " + (string) parcel_owner + " / " + (string) object_owner);
   debug("group= " + (string) parcel_group + " / " + (string) object_group);
   if (object_owner==llGetOwner ()        // IF I am the owner of the object
     || object_owner==parcel_owner        // OR its owner is the same as the parcel I'm on
     || object_group==parcel_group        // OR its group is the same as the parcel I'm on
   )
   {
       return TRUE;
   }
   return FALSE;

}


// Is this a simple request for information or a meta command like !release? integer isSimpleRequest(list list_of_commands) {

   integer len = llGetListLength(list_of_commands);
   integer i;
   // now check every single atomic command
   for (i=0; i < len; ++i)
   {
       string command = llList2String(list_of_commands, i);
       if (!isSimpleAtomicCommand(command))
       {
          return FALSE;
       }
   }
   // all atomic commands passed the test
   return TRUE;

}

// is this a simple atomar command // (a command which only queries some information or releases restrictions) // (e. g.: cmd ends with "=" and a number (@version, @getoutfit, @getattach) or is a !-meta-command) integer isSimpleAtomicCommand(string cmd) {

   // check right hand side of the "=" - sign
   integer index = llSubStringIndex (cmd, "=");
   if (index > -1) // there is a "=" 
   {
       // check for a number after the "="
       string param = llGetSubString (cmd, index + 1, -1);
       if ((integer)param!=0 || param=="0") // is it an integer (channel number)?
       {
           return TRUE;
       }
       // removing restriction
       if ((param == "y") || (param == "rem"))
       {
           return TRUE;
       }
   }
   // check for a leading ! (meta command)
   if (llSubStringIndex(cmd, PREFIX_METACOMMAND) == 0)
   {
       return TRUE;
   }
   // check for @clear
   // Note: @clear MUST NOT be used because the restrictions will be reapplied on next login
   // (but we need this check here because "!release|@clear" is a BROKEN attempt to work around
   // a bug in the first relay implementation. You should refuse to use relay versions < 1013
   // instead.)
   if (cmd == "@clear")
   {
       return TRUE;
   }
 
   // this one is not "simple".
   return FALSE;

}

// If we already have commands from this object pending // because of a permission request dialog, just add the // new commands at the end. // Note: We use a timeout here because the player may // have "ignored" the dialog. integer tryToGluePendingCommands(key id, string commands) {

   if (llStringLength(pendingMessage) > 4000)
   {
       llSay(0, llKey2Name(id) + " is flooding commands. Releasing restrictions.");
       releaseRestrictions();
       return TRUE;
   }
   if ((pendingId == id) && (pendingTime + PERMISSION_DIALOG_TIMEOUT > llGetUnixTime()))
   {
       debug("Gluing " + (string) pendingMessage + " with " + commands);
       pendingMessage = pendingMessage + "|" + commands;
       return TRUE;
   }
   return FALSE;

}


// accept !release even if out of range handleCommandsWhichAreAcceptedOutOfRange(key id, string message) {

   if (id != source)
   {
       return;
   }
   list tokens = llParseString2List (message, [","], []);
   if (llGetListLength (tokens) < 3)
   {
       return;
   }
   string commands = llList2String(tokens, 2);
   list list_of_commands = llParseString2List(commands, ["|"], []);
   if (llListFindList(list_of_commands, ["!release"]) > -1)
   {
       debug("accepted !release although it was out of range");
       releaseRestrictions();
   }

}


// verifies the permission. This includes mode // (off, permission, auto) of the relay and the // identity of the object (owned by parcel people). integer verifyPermission(key id, string name, string message) {

   // is it switched off?
   if (mode == MODE_OFF)
   {
       return FALSE;
   }
   list tokens = llParseString2List (message, [","], []);
   if (llGetListLength (tokens) < 3)
   {
       return FALSE;
   }
   string commands = llList2String(tokens, 2);
   list list_of_commands = llParseString2List(commands, ["|"], []);
   // if we are already having a pending permission-dialog request for THIS object,
   // just add the new commands at the end of the pending command list.
   if (tryToGluePendingCommands(id, commands))
   {
       return FALSE;
   }
   // accept harmless commands silently
   if (isSimpleRequest(list_of_commands))
   {
       return TRUE;
   }
   // check whether this object belongs here
   integer trustworthy = isObjectIdentityTrustworthy(id);
   string warning = "";
   if (!trustworthy)
   {
       warning = "\n\nWARNING: This object is not owned by the people owning this parcel. Unless you know the owner, you should deny this request.";
   }
   // ask in permission-request-mode and/OR in case the object identity is suspisous.
   if (mode == MODE_ASK || !trustworthy)
   {
       pendingId=id;
       pendingName=name;
       pendingMessage = message;
       pendingTime = llGetUnixTime();
       if (llKey2Name(llGetOwnerKey(id)) != "")
       {
           name += " (owned by " + llKey2Name(llGetOwnerKey(id)) + ")";
       }
       
       string text = name + " would like control your viewer." + warning + ".\n\nDo you accept ?";
       debug("Asking for permission isNotEmbedded=" + (string) isNotEmbedded);
       if (isNotEmbedded)
       {
           llDialog (llGetOwner(), text, ["Yes", "No"], DIALOG_CHANNEL);
       }
       llMessageLinked(LINK_SET, ASK_LINK_CHANNEL, text, id);
       debug("Asking for permission");
       return FALSE;
   }
   return TRUE;

}


// --------------------------------------------------- // Executing of commands // ---------------------------------------------------

// execute a non-parsed message // this command could be denied here for policy reasons, (if it were implemenetd) // but this time there will be an acknowledgement execute(string name, key id, string message) {

   list tokens = llParseString2List(message, [","], []);
   string cmd_id = llList2String(tokens, 0); // CheckAttach
   list list_of_commands = llParseString2List(llList2String(tokens, 2), ["|"], []);
   integer len = llGetListLength (list_of_commands);
   integer i;
   string command;
   string prefix;
   for (i=0; i<len; ++i) // execute every command one by one
   {
       // a command is a RL command if it starts with '@' or a metacommand if it starts with '!'
       command = llList2String(list_of_commands, i);
       prefix = llGetSubString(command, 0, 0);
       if (prefix == PREFIX_RL_COMMAND) // this is a RLV command
       {
           executeRLVCommand(cmd_id, id, command);
       }
       else if (prefix == PREFIX_METACOMMAND) // this is a metacommand, aimed at the relay itself
       {
           executeMetaCommand(cmd_id, id, command);
       }
   }

}

// executes a command for the restrained life viewer // with some additinal magic like book keeping executeRLVCommand(string cmd_id, string id, string command) {

   command = llToLower(command);
   // we need to know whether whether is a rule or a simple command
   list tokens = llParseString2List(command, ["="], []);
   string behav = llList2String(tokens, 0); // @getattach:skull
   string param = llList2String(tokens, 1); // 2222
   integer ind = llListFindList(restrictions, [behav]);
   tokens = llParseString2List(behav, [":"], []); // @sit:<uuid>
   string behavName = llList2String (tokens, 0);  // @sit
   string option = llList2String (tokens, 1);     // <uuid>
   
   debug("executeRLVCommand: behav=!" + behav + "! param=!" + param + "!");
   if (param=="n" || param=="add") // add to restrictions
   {
       if (ind < 0)
       {
           if (llGetListLength(restrictions) == 0)
           {
               sendRLCmd(RVL_COMMAND_START);
               llMessageLinked(LINK_SET, STATUS_LINK_CHANNEL, "start", id);
           } 
           restrictions += [behav];
       }
       source = id; // we know that source is either NULL_KEY or id already
   }
   else if (param == "y" || param == "rem") // remove from restrictions
   {
       if (ind > -1) 
       {
           restrictions = llDeleteSubList (restrictions, ind, ind);
       }
       if (llGetListLength(restrictions) == 0)
       {
           source = NULL_KEY;
           sendRLCmd(RVL_COMMAND_END);
       }
       removeFromPendingList(behav);
   }
   else if (param == "force")
   {
       if (llListFindList(refusedForceCommands, [behavName]) >= 0)
       {
           debug("rejected force-command: behav=!" + behav + "! behavName=!" + behavName + "!");
           ack(cmd_id, id, command, "ko");
           return;
       }
   }
   workaroundForAtClear(command);
   rememberForceSit(behavName, option, param);
   sendRLCmd(command); // execute command
   ack(cmd_id, id, command, "ok"); // acknowledge

}

// check for @clear // Note: @clear MUST NOT be used because the restrictions will be reapplied on next login // (but we need this check here because "!release|@clear" is a BROKEN attempt to work around // a bug in the first relay implementation. You should refuse to use relay versions < 1013 // instead.) workaroundForAtClear(string command) {

   if (command == "@clear")
   {
       releaseRestrictions();
   }

}

// remembers the time and object if this command is a force sit rememberForceSit(string behavName, string option, string param) {

   // clear lastForceSitDestination in case we are now prevented from standing up and
   // the force sit was long ago. Note: restrictions is checked to prevent the
   // clearance in case @unsit is just send again on login
   if (behavName == "@unsit")
   {
       if (llListFindList(restrictions, ["@unsit"]) < 0)
       {
           if (lastForceSitTime + MAX_TIME_AUTOACCEPT_AFTER_FORCESIT < llGetUnixTime())
           {
               debug("clearing lastForceSitDestination");
               lastForceSitDestination = NULL_KEY;
           }
       }
   }
   
   if (param != "force")
   {
       return;
   }
   debug("'force'-command:" + behavName + "/" + option);
   if (behavName != "@sit")
   {
       return;
   }
   lastForceSitDestination = (key) option;
   lastForceSitTime = llGetUnixTime();
   debug("remembered force sit");

}

// executes a meta command which is handled by the relay itself executeMetaCommand(string cmd_id, string id, string command) {

   if (command == PREFIX_METACOMMAND + "version") // checking relay protocol version
   {
       ack(cmd_id, id, command, (string) RLVRS_PROTOCOL_VERSION);
   }
   else if (command == PREFIX_METACOMMAND + "implversion") // checking relay version
   {
       ack(cmd_id, id, command, RLVRS_IMPL_VERSION);
   }
   else if (command == PREFIX_METACOMMAND + "release") // release all the restrictions (end session)
   {
       releaseRestrictions();
       ack(cmd_id, id, command, "ok");
   }
   else if (command == PREFIX_METACOMMAND + "pong")
   {
       loginWaitingForPong = FALSE;
   }

}

// removes a restriction from the list of pending commands removeFromPendingList(string behav) {

   string search = behav + "=";
   // don't do the expensive parsing (string operations are very slow in pre- 
   // mono LSL) in case we can detect fast that this one is not in the list.
   if (llSubStringIndex(pendingMessage, search) < 0)
   {
       return;
   }
   list tokens = llParseString2List(pendingMessage, [","], []);
   list commands = llParseString2List(llList2String(tokens, 2), ["|"], []);
   integer modified = FALSE;
   integer len = llGetListLength(commands);
   integer i;
   for (i = len - 1; i >= 0; i--)
   {
       string cmd = llList2String(commands, i);
       if (llSubStringIndex(cmd, search) == 0)
       {
           if (llSubStringIndex(cmd, "=n") > -1 || llSubStringIndex(cmd, "=add") > -1)
           {
               commands = llDeleteSubList(commands, i, i);
               modified = TRUE;
           } 
       }
   }
   if (modified)
   {
       if (llGetListLength(commands) > 0)
       {
           pendingMessage = llList2String(tokens, 0) + "," + llList2String(tokens, 1) + "," + llDumpList2String(commands, "|");
       }
       else
       {
           clearPendingMessages();
       }
   }

}


// lift all the restrictions (called by !release and by turning the relay off) releaseRestrictions() {

   source = NULL_KEY;
   integer i;
   integer len = llGetListLength (restrictions);
   for (i = 0; i < len; ++i)
   {
       sendRLCmd(llList2String (restrictions, i) + "=y");
   }
   sendRLCmd(RVL_COMMAND_END);
   lastForceSitDestination = NULL_KEY;
   restrictions = [];
   loginPendingForceSit = FALSE;
   clearPendingMessages();
   llMessageLinked(LINK_SET, STATUS_LINK_CHANNEL, "release", NULL_KEY);

}


// deletes the list of pending messsages clearPendingMessages() {

   // clear pending request
   pendingName = "";
   pendingId = NULL_KEY;
   pendingMessage = "";
   pendingTime = 0;

}


// processes a message send on the relay channel processRelayMessage(string name, key id, string message) {

   if (mode== MODE_OFF)
   {
       debug("deactivated - ignoring commands");
       return; // mode is 0 (off) => reject
   }
   debug("LISTEN: " + message);
   if (!verifyWeAreTarget(message))
   {
      return;
   }
   if (!verifySourceType(id))
   {
       return;
   }
   debug("Got message (active world object " + (string) source + "): name=" + name+ " id=" + (string) id + " message=" + message);

   if (source)
   {
       if (source != id)
       {
           if (isObjectNear(source))
           {
               debug("already used by another object => reject");
               return;
           }
           else
           {
               debug("already used by another object, which is out of range");
               releaseRestrictions();
           }
       }
   }
   if (!isObjectNear(id)) 
   {
       handleCommandsWhichAreAcceptedOutOfRange(id, message);
       return;
   }
   if (!isObjectKnow(id))
   {
       debug("asking for permission because source is NULL_KEY");
       if (!verifyPermission(id, name, message))
       {
           return;
       }
   }
   debug("Executing: " + (string) source);
   execute(name, id, message);

}

// --------------------------------------------------- // mode and dialog handling // ---------------------------------------------------


// shows current mode as string showModeDescription() {

   if (isNotEmbedded)
   {
       llOwnerSay(llList2String(MODE_DESCRIPTIONS, mode));
   }
   llMessageLinked(LINK_SET, STATUS_LINK_CHANNEL, "show_mode", (key) ((string) mode));

}


// process the Yes/No buttons of the permission dialog processDialogResponse(key id, string message) {

   if (pendingId)
   {
       if (message == "Yes") // pending request authorized => process it
       {
           execute(pendingName, pendingId, pendingMessage);
       }
       clearPendingMessages();
   }

}


// --------------------------------------------------- // initialisation and login handling // ---------------------------------------------------

init() {

   sendRLCmd("@clear");
   llOwnerSay("Waiting for plugins to initialize...");
   llSleep(5);
   mode = MODE_ASK;
   llListen(RLVRS_CHANNEL, "", "", "");
   llListen(DIALOG_CHANNEL, "", llGetOwner(), "");
   if (llGetFreeMemory() < 10000)
   {
       llSay(0, llKey2Name(llGetOwner()) + ", your relay is having very little free script memory and is likly to crash during use. Please verify that it was compiled using Mono.");
   }
   llMessageLinked(LINK_SET, STATUS_LINK_CHANNEL, "init", NULL_KEY);
   llOwnerSay("Initialized and ready");
   showModeDescription();
   debug("Free Memory: " + (string) llGetFreeMemory());

}


// sends the known restrictions (again) to the RL-viewer // (call this functions on login) reinforceKnownRestrictions() {

   integer i;
   integer len = llGetListLength(restrictions);
   string restr;
   debug("source=" + (string) source);
   if (len > 0)
   {
       sendRLCmd(RVL_COMMAND_START);
   }
   for (i=0; i < len; ++i)
   {
       restr = llList2String(restrictions, i);
       debug("restr=" + restr);
       sendRLCmd(restr + "=n");
       if (restr == "@unsit")
       {
           loginPendingForceSit = TRUE;
       }
   }

}

// send a ping request and start a timer pingWorldObjectIfUnderRestrictions() {

   loginWaitingForPong = FALSE;
   if (source)
   {
       ack("ping", source, "ping", "ping");
       timerTickCounter = 0;
       llSetTimerEvent(1.0);
       loginWaitingForPong = TRUE;
   }

}

sendForceSitDuringLogin() {

   key sitTarget = source;
   if (lastForceSitDestination)
   {
       sitTarget = lastForceSitDestination;
   }
   debug("Force sit during login on " + (string) sitTarget + " (source=" + (string) source + ", lastForceSitDestination=" + (string) lastForceSitDestination + ")");
   sendRLCmd ("@sit:" + (string) sitTarget + "=force");

}


// processes a timer event processTimer() {

   timerTickCounter++;
   debug("timer (" + (string) timerTickCounter + "): waiting for pong: " + (string) loginWaitingForPong + " pendingForceSit: " + (string) loginPendingForceSit);
   if (loginWaitingForPong && (timerTickCounter >= LOGIN_DELAY_WAIT_FOR_PONG))
   {
       llWhisper(0, "Lucky Day: " + llKey2Name(llGetOwner()) + " is freed because the device is not available.");
       loginWaitingForPong = FALSE;
       loginPendingForceSit = FALSE;
       releaseRestrictions();
   }
   if (loginPendingForceSit)
   {
       integer agentInfo = llGetAgentInfo(llGetOwner());
       if (agentInfo & AGENT_SITTING)
       {
           loginPendingForceSit = FALSE;
           debug("is sitting now");
       }
       else if (timerTickCounter == LOGIN_DELAY_WAIT_FOR_FORCE_SIT)
       {
           llWhisper(0, "Lucky Day: " + llKey2Name(llGetOwner()) + " is freed because sitting down again was not possible.");
           loginPendingForceSit = FALSE;
           releaseRestrictions();
       }
       else
       {
           sendForceSitDuringLogin();
       }
   }
   if (!loginPendingForceSit && !loginWaitingForPong)
   {
       llSetTimerEvent(0.0);
   }

}

processLinkMessage(key id, string message) {

   if (message == "safeword")
   {
       llSay(0, llKey2Name(llGetOwner()) + " said the safeword. Freeing and deactivating relay.");
       releaseRestrictions();
       mode = MODE_OFF;
       showModeDescription();
       return;
   }
   if (message == "unlock")
   {
       if (id)
       {
           llSay(0, llKey2Name(id) + " freed " + llKey2Name(llGetOwner()) + " by unlocking the relay.");
       }
       releaseRestrictions();
       return;
   }
    if (message == "mode")
    {
        if (source)
       {
           llOwnerSay("Sorry, you cannot change the relay mode while it is active.");
           return;
       }
        mode = ((integer) ((string) id)) % 3;    
       showModeDescription();
       return;
    }
   if (message == "refusedForceCommands")
   {
       refusedForceCommands = llParseString2List((string) id, [","], []);
       return;
   }
   if (message == "embedded")
   {
       isNotEmbedded = FALSE;
       return;
   }

}


default {

   state_entry()
   {
       init();
   }

   on_rez(integer start_param)
   {
       // relogging, we must refresh the viewer and ping the object if any
       // if mode is not OFF, fire all the stored restrictions
       if (mode)
       {
           reinforceKnownRestrictions();
           pingWorldObjectIfUnderRestrictions();
       }
       // remind the current mode to the user
       showModeDescription();
   }
   timer()
   {
       processTimer();
   }
   listen(integer channel, string name, key id, string message)
   {
       if (channel==RLVRS_CHANNEL)
       {
           processRelayMessage(name, id, message);
       }
       else if (channel==DIALOG_CHANNEL)
       {
           processDialogResponse(id, message);
       }
   }
   
   link_message(integer sender, integer channel, string message, key id)
   {
       if (channel == CMD_LINK_CHANNEL)
       {
           processLinkMessage(id, message);
       }
       else if (channel == DIALOG_LINK_CHANNEL)
       {
           processDialogResponse(id, message);
       }
   }
   touch_start(integer num_detected)
   {
       if (!isNotEmbedded)
       {
           return;
       }
       // touched by user => cycle through OFF/ON_PERMISSION/ON_ALWAYS modes
       key toucher = llDetectedKey(0);
       if (toucher != llGetOwner())
       {
           return;
       }
       if (source)
       {
           llOwnerSay("Sorry, you cannot change the relay mode while it is active.");
           return;
       }
       mode = (mode + 1) % 3;
       if (mode == MODE_OFF) {
           releaseRestrictions();
       }
       showModeDescription();
   }
   changed(integer change)
   {
       if (change & (CHANGED_OWNER | CHANGED_INVENTORY | CHANGED_ALLOWED_DROP)) 
       {
            llResetScript();
       }
   }

}

</lsl>