From 0f6c8d50a99997ac7829864b1c93362b50f1bbf3 Mon Sep 17 00:00:00 2001
From: Diego Nehab <diego@tecgraf.puc-rio.br>
Date: Sun, 25 May 2003 01:54:13 +0000
Subject: Porting to LUA 5.0 final

---
 etc/tftp.lua | 131 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 etc/tftp.lua

(limited to 'etc')

diff --git a/etc/tftp.lua b/etc/tftp.lua
new file mode 100644
index 0000000..a0db68e
--- /dev/null
+++ b/etc/tftp.lua
@@ -0,0 +1,131 @@
+-----------------------------------------------------------------------------
+-- TFTP support for the Lua language
+-- LuaSocket 1.5 toolkit.
+-- Author: Diego Nehab
+-- Conforming to: RFC 783, LTN7
+-- RCS ID: $Id$
+-----------------------------------------------------------------------------
+
+local Public, Private = {}, {}
+local socket = _G[LUASOCKET_LIBNAME] -- get LuaSocket namespace
+socket.tftp = Public  -- create tftp sub namespace
+
+-----------------------------------------------------------------------------
+-- Program constants
+-----------------------------------------------------------------------------
+local char = string.char
+local byte = string.byte
+
+Public.PORT = 69
+Private.OP_RRQ = 1
+Private.OP_WRQ = 2
+Private.OP_DATA = 3
+Private.OP_ACK = 4
+Private.OP_ERROR = 5
+Private.OP_INV = {"RRQ", "WRQ", "DATA", "ACK", "ERROR"}
+
+-----------------------------------------------------------------------------
+-- Packet creation functions
+-----------------------------------------------------------------------------
+function Private.RRQ(source, mode)
+	return char(0, Private.OP_RRQ) .. source .. char(0) .. mode .. char(0)
+end
+
+function Private.WRQ(source, mode)
+	return char(0, Private.OP_RRQ) .. source .. char(0) .. mode .. char(0)
+end
+
+function Private.ACK(block)
+	local low, high
+	low = math.mod(block, 256)
+	high = (block - low)/256
+	return char(0, Private.OP_ACK, high, low) 
+end
+
+function Private.get_OP(dgram)
+    local op = byte(dgram, 1)*256 + byte(dgram, 2)
+    return op
+end
+
+-----------------------------------------------------------------------------
+-- Packet analysis functions
+-----------------------------------------------------------------------------
+function Private.split_DATA(dgram)
+	local block = byte(dgram, 3)*256 + byte(dgram, 4)
+	local data = string.sub(dgram, 5)
+	return block, data
+end
+
+function Private.get_ERROR(dgram)
+	local code = byte(dgram, 3)*256 + byte(dgram, 4)
+	local msg
+	_,_, msg = string.find(dgram, "(.*)\000", 5)
+	return string.format("error code %d: %s", code, msg)
+end
+
+-----------------------------------------------------------------------------
+-- Downloads and returns a file pointed to by url
+-----------------------------------------------------------------------------
+function Public.get(url)
+    local parsed = socket.url.parse(url, {
+        host = "",
+        port = Public.PORT,
+        path ="/",
+        scheme = "tftp"
+    })
+    if parsed.scheme ~= "tftp" then
+        return nil, string.format("unknown scheme '%s'", parsed.scheme)
+    end
+    local retries, dgram, sent, datahost, dataport, code
+    local cat = socket.concat.create()
+    local last = 0
+	local udp, err = socket.udp()
+	if not udp then return nil, err end
+    -- convert from name to ip if needed
+	parsed.host = socket.toip(parsed.host)
+	udp:timeout(1)
+    -- first packet gives data host/port to be used for data transfers
+    retries = 0
+	repeat 
+		sent, err = udp:sendto(Private.RRQ(parsed.path, "octet"), 
+            parsed.host, parsed.port)
+		if err then return nil, err end
+		dgram, datahost, dataport = udp:receivefrom()
+        retries = retries + 1
+	until dgram or datahost ~= "timeout" or retries > 5
+	if not dgram then return nil, datahost end
+    -- associate socket with data host/port
+	udp:setpeername(datahost, dataport)
+    -- process all data packets
+	while 1 do
+        -- decode packet
+		code = Private.get_OP(dgram)
+		if code == Private.OP_ERROR then 
+            return nil, Private.get_ERROR(dgram) 
+        end
+		if code ~= Private.OP_DATA then 
+            return nil, "unhandled opcode " .. code 
+        end
+        -- get data packet parts
+		local block, data = Private.split_DATA(dgram)
+        -- if not repeated, write
+        if block == last+1 then
+		    cat:addstring(data)
+            last = block
+        end
+        -- last packet brings less than 512 bytes of data
+		if string.len(data) < 512 then 
+            sent, err = udp:send(Private.ACK(block)) 
+            return cat:getresult()
+        end
+        -- get the next packet
+        retries = 0
+		repeat 
+			sent, err = udp:send(Private.ACK(last))
+			if err then return err end
+			dgram, err = udp:receive()
+            retries = retries + 1
+		until dgram or err ~= "timeout" or retries > 5
+		if not dgram then return err end
+	end
+end
-- 
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