spilltea/plugins/ip_filter.lua

Plugin = {
  name        = "IP Filter (Whitelist/Blacklist)",
  description = [[
Checks that the proxy's outbound IP is in an allowed list on startup.

**Config** (YAML):
```yaml
ips:
  - "1.2.3.4"     # whitelist entry
  - "!5.6.7.8"    # blacklist entry (blocked)
```
- If no IPs are configured, the check is skipped.
  ]],
  on_start          = { sync = false },
  disable_by_default = true,
}

local whitelist = {}
local blacklist = {}

function on_config()
  whitelist, blacklist = {}, {}
  local cfg = get_config()
  if cfg and cfg.ips then
    for _, entry in ipairs(cfg.ips) do
      local trimmed = entry:match("^%s*(.-)%s*$")
      if trimmed ~= "" then
        if trimmed:sub(1, 1) == "!" then
          local ip = trimmed:sub(2):match("^%s*(.-)%s*$")
          if ip ~= "" then table.insert(blacklist, ip) end
        else
          table.insert(whitelist, trimmed)
        end
      end
    end
  end
end

function on_start()
  if #whitelist == 0 and #blacklist == 0 then
    return
  end

  local result, err = shell_pipe("curl -sf https://api.ipify.org 2>/dev/null")
  result = result and result:match("^%s*(.-)%s*$") or nil

  if err or not result or result == "" then
    log("could not determine outbound IP, skipping check")
    notif("IP Filter", "Could not determine outbound IP, skipping check", "warning")
    return
  end

  for _, ip in ipairs(blacklist) do
    if result == ip then
      notif("IP Filter", "Outbound IP " .. result .. " is blacklisted!", "error")
      return
    end
  end

  if #whitelist == 0 then
    return
  end

  for _, ip in ipairs(whitelist) do
    if result == ip then
      return
    end
  end

  notif("IP Filter", "Outbound IP " .. result .. " is not in the whitelist!", "error")
end