diff --git a/src/include/netif/ppp/ppp_impl.h b/src/include/netif/ppp/ppp_impl.h
index b9437603..f978d323 100644
--- a/src/include/netif/ppp/ppp_impl.h
+++ b/src/include/netif/ppp/ppp_impl.h
@@ -472,6 +472,12 @@ int sifnpmode(ppp_pcb *pcb, int proto, enum NPmode mode);
 void netif_set_mtu(ppp_pcb *pcb, int mtu);
 int netif_get_mtu(ppp_pcb *pcb);
 
+#if CCP_SUPPORT
+int ccp_test(ppp_pcb *pcb, u_char *opt_ptr, int opt_len, int for_transmit);
+void ccp_flags_set(ppp_pcb *pcb, int isopen, int isup);
+int ccp_fatal_error(ppp_pcb *pcb);
+#endif /* CCP_SUPPORT */
+
 #if PPP_IDLETIMELIMIT
 int get_idle_time(ppp_pcb *pcb, struct ppp_idle *ip);
 #endif /* PPP_IDLETIMELIMIT */
diff --git a/src/netif/ppp/ppp.c b/src/netif/ppp/ppp.c
index d23f2eba..2264091c 100644
--- a/src/netif/ppp/ppp.c
+++ b/src/netif/ppp/ppp.c
@@ -1091,6 +1091,44 @@ int netif_get_mtu(ppp_pcb *pcb) {
   return pcb->netif->mtu;
 }
 
+#if CCP_SUPPORT
+/*
+ * ccp_test - whether a given compression method is acceptable for use.
+ */
+int
+ccp_test(ppp_pcb *pcb, u_char *opt_ptr, int opt_len, int for_transmit)
+{
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_UNUSED_ARG(opt_ptr);
+  LWIP_UNUSED_ARG(opt_len);
+  LWIP_UNUSED_ARG(for_transmit);
+  return -1;
+}
+
+/*
+ * ccp_flags_set - inform about the current state of CCP.
+ */
+void
+ccp_flags_set(ppp_pcb *pcb, int isopen, int isup)
+{
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_UNUSED_ARG(isopen);
+  LWIP_UNUSED_ARG(isup);
+}
+
+/*
+ * ccp_fatal_error - returns 1 if decompression was disabled as a
+ * result of an error detected after decompression of a packet,
+ * 0 otherwise.  This is necessary because of patent nonsense.
+ */
+int
+ccp_fatal_error(ppp_pcb *pcb)
+{
+  LWIP_UNUSED_ARG(pcb);
+  return 1;
+}
+#endif /* CCP_SUPPORT */
+
 #if PPP_IDLETIMELIMIT
 /********************************************************************
  *