+ /*
+ * This version is used for two purposes:
+ *
+ * RFC 2637 PPTP;
+ * Some Mikrotik Ethernet-over-IP hack.
+ */
+ switch (prot) {
+ case GRE_MIKROTIK_EOIP:
+ /*
+ * The MikroTik hack uses only the key field, and uses it
+ * for its own purposes. If anything other than the version
+ * and K bit are set, report an error and give up.
+ */
+ if ((flags & ~GRE_VERS_MASK) != GRE_KP) {
+ ND_PRINT(" unknown-eoip-flags-%04x!", flags);
+ return;
+ }
+ break;
+ default:
+ /*
+ * XXX - what should we do if it's not ETHERTYPE_PPP?
+ */
+ break;
+ }