githubmirror/libnet

lua/nfq-test
82 строки2 KB
Sam Roberts
Updated lua bindings, they are a mess, but at least they are here.
11 фев 2010, 00:46
11 фев 2010, 00:4696bc726
#!/usr/bin/env lua
--[[

To verify input:

sudo tcpdump -v -X -n -s0 icmp and src host 192.168.41.177

Running with bing from my host to build:

--- 192.168.41.177 statistics ---
bytes   out    in   dup  loss   rtt (ms): min       avg       max   std dev
   44 34512 34512          0%           0.075     0.081     2.228     0.013
  108 34512 34512          0%           0.077     0.085     1.739     0.012

--- build.wurldtech.local statistics ---
bytes   out    in   dup  loss   rtt (ms): min       avg       max   std dev
   44 34512 34512          0%           0.120     0.128    10.103     0.091
  108 34512 34512          0%           0.153     0.164    10.156     0.129

--- estimated link characteristics ---
host                              bandwidth       ms
build.wurldtech.local               33.032Mbps       0.045

It looks from top that lua usage is 45% cpu in this case.

NOTE! Any console (especially to X) I/O causes cpu usage to go down, because
it blocks lua (so also slows traffic down).

]]

require"nfq"

local function quiet() end

print = quiet

os.execute"iptables -L"
os.execute"iptables -t filter -D OUTPUT 1"
os.execute"iptables -t filter -I OUTPUT 1 -p icmp -j QUEUE"
os.execute"iptables -L"

local function h(s)
    local bytes = {string.byte(s, 1, 10)}
    for i,v in ipairs(bytes) do
        bytes[i] = string.format("%02x", bytes[i])
    end
    return table.concat(bytes)
end

local function setttl()
    -- replace TTL with 1
    -- TTL is at byte 9, counting from 1
    local replace = payload:sub(1, 8) .. "\1" .. payload:sub(10)

    print(h(replace))

    return "accept", replace
end

local function damage(payload)
    local start = payload:sub(1, -2)
    local last = string.char(payload:byte(-1) + 1)
    local replace = start..last

    print(h(replace))

    return "accept", replace
end

local payload

nfq.loop(function (nfqdata)
    print("nfqdata", nfqdata)

    local payload = nfq.get_payload(nfqdata)

    print(h(payload))

    --return setttl(payload)
    return damage(payload)
    --return "drop"
end)