Grid+ Subscription Repeater (CC/NexCore3)

local userDir = ".users"

--SHA-256 API by GravityScore
local MOD = 2^32
local MODM = MOD-1

local function memoize(f)
    local mt = {}
    local t = setmetatable({}, mt)
    function mt:__index(k)
        local v = f(k)
        t[k] = v
        return v
    end
    return t
end

local function make_bitop_uncached(t, m)
    local function bitop(a, b)
        local res,p = 0,1
        while a ~= 0 and b ~= 0 do
            local am, bm = a % m, b % m
            res = res + t[am][bm] * p
            a = (a - am) / m
            b = (b - bm) / m
            p = p*m
        end
        res = res + (a + b) * p
        return res
    end
    return bitop
end

local function make_bitop(t)
    local op1 = make_bitop_uncached(t,2^1)
    local op2 = memoize(function(a) return memoize(function(b) return op1(a, b) end) end)
    return make_bitop_uncached(op2, 2 ^ (t.n or 1))
end

local bxor1 = make_bitop({[0] = {[0] = 0,[1] = 1}, [1] = {[0] = 1, [1] = 0}, n = 4})

local function bxor(a, b, c, ...)
    local z = nil
    if b then
        a = a % MOD
        b = b % MOD
        z = bxor1(a, b)
        if c then z = bxor(z, c, ...) end
        return z
    elseif a then return a % MOD
    else return 0 end
end

local function band(a, b, c, ...)
    local z
    if b then
        a = a % MOD
        b = b % MOD
        z = ((a + b) - bxor1(a,b)) / 2
        if c then z = bit32_band(z, c, ...) end
        return z
    elseif a then return a % MOD
    else return MODM end
end

local function bnot(x) return (-1 - x) % MOD end

local function rshift1(a, disp)
    if disp < 0 then return lshift(a,-disp) end
    return math.floor(a % 2 ^ 32 / 2 ^ disp)
end

local function rshift(x, disp)
    if disp > 31 or disp < -31 then return 0 end
    return rshift1(x % MOD, disp)
end

local function lshift(a, disp)
    if disp < 0 then return rshift(a,-disp) end
    return (a * 2 ^ disp) % 2 ^ 32
end

local function rrotate(x, disp)
    x = x % MOD
    disp = disp % 32
    local low = band(x, 2 ^ disp - 1)
    return rshift(x, disp) + lshift(low, 32 - disp)
end

local k = {
    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
    0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
    0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
    0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
    0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
    0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
}

local function str2hexa(s)
    return (string.gsub(s, ".", function(c) return string.format("%02x", string.byte(c)) end))
end

local function num2s(l, n)
    local s = ""
    for i = 1, n do
        local rem = l % 256
        s = string.char(rem) .. s
        l = (l - rem) / 256
    end
    return s
end

local function s232num(s, i)
    local n = 0
    for i = i, i + 3 do n = n*256 + string.byte(s, i) end
    return n
end

local function preproc(msg, len)
    local extra = 64 - ((len + 9) % 64)
    len = num2s(8 * len, 8)
    msg = msg .. "\128" .. string.rep("\0", extra) .. len
    assert(#msg % 64 == 0)
    return msg
end

local function initH256(H)
    H[1] = 0x6a09e667
    H[2] = 0xbb67ae85
    H[3] = 0x3c6ef372
    H[4] = 0xa54ff53a
    H[5] = 0x510e527f
    H[6] = 0x9b05688c
    H[7] = 0x1f83d9ab
    H[8] = 0x5be0cd19
    return H
end

local function digestblock(msg, i, H)
    local w = {}
    for j = 1, 16 do w[j] = s232num(msg, i + (j - 1)*4) end
    for j = 17, 64 do
        local v = w[j - 15]
        local s0 = bxor(rrotate(v, 7), rrotate(v, 18), rshift(v, 3))
        v = w[j - 2]
        w[j] = w[j - 16] + s0 + w[j - 7] + bxor(rrotate(v, 17), rrotate(v, 19), rshift(v, 10))
    end

    local a, b, c, d, e, f, g, h = H[1], H[2], H[3], H[4], H[5], H[6], H[7], H[8]
    for i = 1, 64 do
        local s0 = bxor(rrotate(a, 2), rrotate(a, 13), rrotate(a, 22))
        local maj = bxor(band(a, b), band(a, c), band(b, c))
        local t2 = s0 + maj
        local s1 = bxor(rrotate(e, 6), rrotate(e, 11), rrotate(e, 25))
        local ch = bxor (band(e, f), band(bnot(e), g))
        local t1 = h + s1 + ch + k[i] + w[i]
        h, g, f, e, d, c, b, a = g, f, e, d + t1, c, b, a, t1 + t2
    end

    H[1] = band(H[1] + a)
    H[2] = band(H[2] + b)
    H[3] = band(H[3] + c)
    H[4] = band(H[4] + d)
    H[5] = band(H[5] + e)
    H[6] = band(H[6] + f)
    H[7] = band(H[7] + g)
    H[8] = band(H[8] + h)
end

local function sha256(msg)
    msg = preproc(msg, #msg)
    local H = initH256({})
    for i = 1, #msg, 64 do digestblock(msg, i, H) end
    return str2hexa(num2s(H[1], 4) .. num2s(H[2], 4) .. num2s(H[3], 4) .. num2s(H[4], 4) ..
        num2s(H[5], 4) .. num2s(H[6], 4) .. num2s(H[7], 4) .. num2s(H[8], 4))
end

--SHA-256 API end





local tArg = {...}
local progname = fs.getName(shell.getRunningProgram())

local getTime = function()
    return ((os.day()-1)*24)+(os.time()*1000)
end

addUser = function(name,password)
    local file = fs.open(fs.combine(userDir,name),"w")
    local out = {
        password = sha256(password),
        time = getTime(),
        active = true,
    }
    file.write(textutils.serialize(out))
    file.close()
end

if tArg[1] == "adduser" then
    if not tArg[3] then
        return print(progname.." useradd [name] [password]")
    else
        if fs.exists(fs.combine(userDir,tArg[2])) then
            return print("Already exists...")
        end
        return adduser(tArg[2],tArg[3])
    end
elseif tArg[1] == "deluser" then
    if not tArg[2] then
        return print(progname.." deluser [user]")
    else
        if not fs.exists(fs.combine(userDir,tArg[2])) then
            return print("No such user.")
        end
        return fs.delete(fs.combing(userDir,tArg[2]))
    end
end

-- Find modems
local tModems = {}
for n,sModem in ipairs( peripheral.getNames() ) do
    if peripheral.getType( sModem ) == "modem" then
        table.insert( tModems, sModem )
    end
end
if #tModems == 0 then
    print( "No modems found." )
    return
elseif #tModems == 1 then
    print( "1 modem found." )
else
    print( #tModems .. " modems found." )
end

function open( nChannel )
    for n=1,#tModems do
        local sModem = tModems[n]
        peripheral.call( sModem, "open", nChannel )
    end
end

function close( nChannel )
    for n=1,#tModems do
        local sModem = tModems[n]
        peripheral.call( sModem, "close", nChannel )
    end
end

-- Open channels
print( "0 messages repeated." )
open( rednet.CHANNEL_REPEAT )

-- Main loop (terminate to break)
local ok, error = pcall( function()
    local tReceivedMessages = {}
    local tReceivedMessageTimeouts = {}
    local nTransmittedMessages = 0

    while true do
        local sEvent, sModem, nChannel, nReplyChannel, tMessage = os.pullEvent()
        if sEvent == "modem_message" then
            -- Got a modem message, rebroadcast it if it's a rednet thing
            if nChannel == rednet.CHANNEL_REPEAT then
                if type( tMessage ) == "table" and tMessage.nMessageID and tMessage.nRecipient then
                    if not tReceivedMessages[ tMessage.nMessageID ] then
                        -- Ensure we only repeat a message once
                        tReceivedMessages[ tMessage.nMessageID ] = true
                        tReceivedMessageTimeouts[ os.startTimer( 30 ) ] = tMessage.nMessageID

                        -- Send on all other open modems, to the target and to other repeaters
                        for n=1,#tModems do
                            local sOtherModem = tModems[n]
                            peripheral.call( sOtherModem, "transmit", rednet.CHANNEL_REPEAT, nReplyChannel, tMessage )
                            peripheral.call( sOtherModem, "transmit", tMessage.nRecipient, nReplyChannel, tMessage )
                        end

                        -- Log the event
                        nTransmittedMessages = nTransmittedMessages + 1
                        local x,y = term.getCursorPos()
                        term.setCursorPos( 1, y - 1 )
                        term.clearLine()
                        if nTransmittedMessages == 1 then
                            print( nTransmittedMessages .. " message repeated." )
                        else
                            print( nTransmittedMessages .. " messages repeated." )
                        end
                    end
                end
            end

        elseif sEvent == "timer" then
            -- Got a timer event, use it to clear the message history
            local nTimer = sModem
            local nMessageID = tReceivedMessageTimeouts[ nTimer ]
            if nMessageID then
                tReceivedMessageTimeouts[ nTimer ] = nil
                tReceivedMessages[ nMessageID ] = nil
            end

        end
    end
end )
if not ok then
    printError( error )
end

-- Close channels
close( rednet.CHANNEL_REPEAT )