ping.lua

local ffi = require 'ffi'
local uv = require 'uv'

-- Darwin
local AF_INET = 2
local SOCK_RAW = 3
local IPPROTO_RAW = 255

ffi.cdef[[
  int socket(int socket_family, int socket_type, int protocol);
]]

-- Raw socket - if you use IPPROTO_ICMP, then kernel will fill in the correct
-- ICMP header checksum, if IPPROTO_RAW, then it wont.
local sockfd = ffi.C.socket(AF_INET, SOCK_RAW, IPPROTO_RAW)
assert(sockfd >= 0, "Failed to create socket")
p(sockfd)

local raw = uv.new_udp()
assert(raw:open(sockfd))
p(raw)

raw:send("test", "23.253.227.83", 0)