Minor tweaks to OpenOS/etc/rc.d/minitel.lua to improve performance

[Jajasek]

1. When a server is repeating a packet, the destination is cached in rcache and rcache[dest][1] is the same modem the packet arrived through, the packet should not be repeated. This could be solved by adding a condition in the function sendPacket (on line 119).
2. The comment on line 37 suggests the time in rcache should be updated when a new packet from that computer is received, but it is not implemented. The function processPacket writes to rcache only if the computer is not cached. The condition on line 189 should be removed, the line rcache[sender] = {localModem,from,computer.uptime()+cfg.rctime} should be executed for all packets. Therefore when 2 computers periodically communicate, the servers between them never forgot the route. Also, it should be executed before the ack packet is sent. I therefore suggest to move it before the line 172.
3. Cosmetic issue: the packets contain the vPort entry, but it is not documented in the comment on line 10.

[Jajasek]

I have done some more playtesting and revealed another 2, much more severe, mistakes.

4. In file OpenOS/usr/lib/minitel.lua, function net.rsend() returns true if any ack packet is seen, not only the one with rpid == pid.
5. The broadcast messages are totally broken. I wonder how could this error persist here for so long time. When the function processPacket() encounters a broadcast message, it pushes net_broadcast signal, but the arrangement of the conditionals prevent it from routing the packet. I fixed it and this is my solution (it fixes even problem 2 mentioned above):

   local function processPacket(_,localModem,from,pport,_,packetID,packetType,dest,sender,vPort,data,...)
   pruneCache()
   if pport == cfg.port or pport == 0 then -- for linked cards
   dprint(cfg.port,vPort,packetType,dest)
   if checkPCache(packetID) then return end
   dprint("rcache: "..sender..":", localModem,from,computer.uptime())
   rcache[sender] = {localModem,from,computer.uptime()+cfg.rctime}
   if dest:sub(1,1) == "~" then -- broadcasts start with ~
     computer.pushSignal("net_broadcast",sender,vPort,data)
   end
   if dest == hostname then
     if packetType == 1 then
       sendPacket(genPacketID(),2,sender,hostname,vPort,packetID)
     end
     if packetType == 2 then
       dprint("Dropping "..data.." from queue")
       pqueue[data] = nil
       computer.pushSignal("net_ack",data)
     end
     if packetType ~= 2 then
       computer.pushSignal("net_msg",sender,vPort,data)
     end
   elseif cfg.route then -- repeat packets if route is enabled
     sendPacket(packetID,packetType,dest,sender,vPort,data,localModem)
   end
   if not pcache[packetID] then -- add the packet ID to the pcache
     pcache[packetID] = computer.uptime()+cfg.pctime
   end
   end
   end

[Leonard2]

Thanks a lot for the fix!

[Kurtoid]

Can you add this as a pull request?