Change hierarchi char from '<' to '^', fix some issues

This is kind of untested. I've asked Izaya to test it...

oc/hierarchi.lua

@@ -71,9 +71,9 @@ processFrom = function (incoming, from)
 		if from:sub(1, netname:len()) == netname then
 			return
 		end
-		return "<" .. from
+		return "^" .. from
 	else
-		if from:sub(1, 1) == "<" then
+		if from:sub(1, 1) == "^" then
 			return
 		end
 		return netname .. from
@@ -86,7 +86,7 @@ processTo = function (incoming, nto)
 		end
 		return nto:sub(netname:len() + 1)
 	else
-		if nto:sub(1, 1) ~= "<" then
+		if nto:sub(1, 1) ~= "^" then
 			return
 		end
 		return nto:sub(2)

oc/tcpdial.lua

@@ -28,8 +28,8 @@ local function verify(d)
 	local hops, src, dst, data = cdlib.decode(d)
 	if not data then return end
 	-- Just a bit of filtering
-	if dst:sub(1, 1) ~= "<" then return end
-	if d:len() > 2021 then return end
+	if dst:sub(1, 1) ~= "^" then return end
+	if d:len() > 2022 then return end
 	return true
 end
 
@@ -55,10 +55,17 @@ local function readerRoutine()
 		for i = 1, sz do
 			dat = dat .. readByte()
 		end
-		md.broadcast(4957, "copper", dat)
+		if dat ~= "" then
+			md.broadcast(4957, "copper", dat)
+		end
 	end
 end
 
+event.timer(10, function ()
+	tcp:write("\x00\x00")
+	tcp:flush()
+end, math.huge)
+
 local primary = coroutine.create(readerRoutine)
 while true do
 	local et, _, _, p, _, m, d = event.pull(0.1)

protocol.1

@@ -3,14 +3,17 @@ Copper Protocol :: Hierarchial Gateways
 
 "Hierarchial Gateways" are a system for ISP-like bodies to prevent their
  users from causing havoc.
+Note that this is not the only possible system, and implementors can do as they wish regarding addressing.
+(However, for this reason, applications should allow specification of a prefix to all "internet"-level addresses.)
+
 They are simply base low-level Copper nodes with two interfaces and the
  following rules:
 
  For the FROM address:
 
 If it's on the parent side, reject if it's prefixed with hostname .. "/",
- otherwise prefix it with "<".
-If it's on the child side, reject if it's prefixed with "<",
+ otherwise prefix it with "^".
+If it's on the child side, reject if it's prefixed with "^",
  otherwise prefix it with hostname .. "/".
 
  For the TO address:
@@ -18,11 +21,11 @@ If it's on the child side, reject if it's prefixed with "<",
 If it's on the parent side, reject unless prefixed with hostname .. "/",
  otherwise remove that.
  (Optionally, if the name is "*", bypass this rule completely.
-  This is not recommended, though, as this allows sending a "complete broadcast packet" via "[some amount of <]*".)
+  This is not recommended, though, as this allows sending a "complete broadcast packet" via "[some amount of ^]*".)
 
-If it's on the child side, reject unless prefixed with "<",
+If it's on the child side, reject unless prefixed with "^",
  otherwise remove that.
- (Optionally, if the name is "<*", reject anyway.
+ (Optionally, if the name is "^*", reject anyway.
   This is a measure which you may or may not wish to take - if the above 'complete broadcast' possibility has been implemented, then it is a must.)
 
  For the packet's general routing:
@@ -54,3 +57,10 @@ Possible uses of hierarchial gateways:
     following the same protocol as everything else in Copper,
     unlike certain competitors
 2. ISPs within servers, perhaps those using the hubs
+
+
+Errata:
+
+Previous versions of the spec used "<" - this was not very usable from most shells on most operating systems.
+It has been replaced with "^".
+It was not explicitly specified that this was not the only way of doing things - this has been corrected.

protocol.2

@@ -37,6 +37,10 @@ Combined with correctly-forgetting packet caches, this should prevent
 
 The final header byte is the actual indicator of what is in the packet.
 
+There are two sections of packet types:
+
+-- Basic Datagrams
+
 0x00 indicates that this is an unreliable packet.
 0x01 indicates that this is a reliable packet, expecting acknowledgement.
 0x02 indicates that this is an acknowledgement for a reliable packet.
@@ -59,7 +63,46 @@ Bob receives it successfully on the second time, and sends back a
 
 Alice receives the response and does not send a third packet.
 
+-- Connections
+
+0x03 : Request Connection Start
+This is similar to an 0x01 reliable packet expecting acknowledgement in how it is to be sent,
+ including the usual packetID randomization, and multiple attempts.
+However, the data must be two bytes, and these first two bytes must be the new port number.
+The port numbers that ought to be used for active connections are 0x8000 to 0xFFFF.
+The response must be on that port number.
+
+0x04 : Request Connection Start / Response
+This is sent on the port given by a Request Connection Start to accept the connection.
+It has the same format as 0x03 (new port number).
+This establishes the connection, and data transmission can begin.
+Connections die if no packets have been received by either side for at least 60 seconds.
+It is recommended the connection "ping" every 15 seconds.
+
+- The following packets have the current sequence number as their packetID.
+  This variable is per-connection-side, starts at 0,
+  and is incremented after a Connection Data packet
+   sent by that side.
+
+0x05 : Connection Data
+If 0 bytes, this serves as a ping (not a packet)
+The sender's sequence number is incremented by 1 before sending.
+The reply is a Connection Acknowledgement with the same sequence number (but no data)
+
+0x06 : Connection Resequencing
+Specifies that the next data packet's sequence number is going to be 0.
+(The packet has the current sequence number, to put it in context.)
+It is this in particular which requires connections keep:
+ 1. A map of sequence number -> data (flushed when data is read)
+ 2. A list of sequence numbers to read.
+When ready, a connection data acknowledgement should be given with sequence number 0.
+
+0x07 : Connection Data Acknowledgement
+Sent from the target of 0x05/0x06 to the sender. For 0x05, has the sequence number of the associated data.
+
 ERRATA:
 
 When this document was originally posted, the relib header was described as 6 bytes despite a total of 7 bytes being specified.
 Thanks to @skyem123 for finding the issue.
+
+The "Connections" section is a recent extension (August 28th 2017)

tcprouter.lua

@@ -35,14 +35,17 @@ local function getpacket(s)
 	local l = getbyte(s)
 	if not l then error("framing bad") end
 	local sz = string.byte(l) + (string.byte(h) * 256)
-	if sz > 2021 then error("packet too large") end
+	if sz > 2022 then error("packet too large") end
 	local data = ""
 	for i = 1, sz do
 		local dbt = getbyte(s)
 		if not dbt then error("terminated early") end
 		data = data .. dbt
 	end
-	return cdlib.decode(data)
+	if data == "" then
+		return false
+	end
+	return true, cdlib.decode(data)
 end
 
 local function checkLen(name)
@@ -52,10 +55,10 @@ local function checkLen(name)
 end
 
 local function translateSend(hops, src, dst, data, srname, tgsock, tgname)
-	if src:sub(1, 1) == "<" then return end
-	if dst:sub(1, tgname:len() + 2) ~= "<" .. tgname .. "/" then return end
+	if src:sub(1, 1) == "^" then return end
+	if dst:sub(1, tgname:len() + 2) ~= "^" .. tgname .. "/" then return end
 	-- Ok, all rejection rules have been handled
-	src = "<" .. srname .. "/" .. src
+	src = "^" .. srname .. "/" .. src
 	dst = dst:sub(tgname:len() + 3)
 	src, dst = checkLen(src), checkLen(dst)
 	if src and dst then
@@ -82,19 +85,24 @@ local function messageroutine(tbl)
 	print("confirmed name " .. name)
 	tbl[3] = name
 	while true do
-		local hops, src, dst, data = getpacket(tbl[2])
-		if not data then
-			error("Bad Copper packet")
-		end
-		print("packet", src, dst)
-		if hops ~= 255 then
-			for _, v in ipairs(sockets) do
-				if v[3] then
-					if v ~= tbl then
-						translateSend(hops + 1, src, dst, data, name, v[2], v[3])
+		local rcv, hops, src, dst, data = getpacket(tbl[2])
+		if rcv then
+			if not data then
+				error("Bad Copper packet")
+			end
+			print("packet", src, dst)
+			if hops ~= 255 then
+				for _, v in ipairs(sockets) do
+					if v[3] then
+						if v ~= tbl then
+							translateSend(hops + 1, src, dst, data, name, v[2], v[3])
+						end
 					end
 				end
 			end
+		else
+			-- Ping response
+			tbl[2]:send("\x00\x00")
 		end
 	end
 end