mirror of
https://github.com/lunarmodules/luasocket.git
synced 2024-11-08 14:28:21 +01:00
132 lines
4.2 KiB
Lua
132 lines
4.2 KiB
Lua
-----------------------------------------------------------------------------
|
|
-- TFTP support for the Lua language
|
|
-- LuaSocket 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
|