Add REJECT_CLOUDFLARE_IPS flag to filter out Cloudflare-owned IPs from

DNS updates

  IP detection providers can sometimes return a Cloudflare anycast IP
  instead
  of the user's real public IP, causing incorrect DNS updates. When
  REJECT_CLOUDFLARE_IPS=true, detected IPs are checked against
  Cloudflare's
  published IP ranges (ips-v4/ips-v6) and rejected if they match.

src/main.rs

@@ -1,3 +1,4 @@
+mod cf_ip_filter;
 mod cloudflare;
 mod config;
 mod domain;