ppp: silently drop invalid packets

diff --git a/gatchat/gatppp.c b/gatchat/gatppp.c
index 3450ce3..f200ae7 100644 (file)
--- a/gatchat/gatppp.c
+++ b/gatchat/gatppp.c
@@ -71,24 +71,44 @@ void ppp_debug(GAtPPP *ppp, const char *str)
        ppp->debugf(str, ppp->debug_data);
 }
 
+/*
+ * Silently discard packets which are received when they shouldn't be
+ */
+static inline gboolean ppp_drop_packet(GAtPPP *ppp, guint16 protocol)
+{
+       switch (ppp->phase) {
+       case PPP_PHASE_ESTABLISHMENT:
+       case PPP_PHASE_TERMINATION:
+               if (protocol != LCP_PROTOCOL)
+                       return TRUE;
+               break;
+       case PPP_PHASE_AUTHENTICATION:
+               if (protocol != LCP_PROTOCOL && protocol != CHAP_PROTOCOL)
+                       return TRUE;
+               break;
+       case PPP_PHASE_DEAD:
+               return TRUE;
+       case PPP_PHASE_NETWORK:
+               if (ppp->net == NULL)
+                       return TRUE;
+               break;
+       }
+
+       return FALSE;
+}
+
 static void ppp_receive(const unsigned char *buf, gsize len, void *data)
 {
        GAtPPP *ppp = data;
        guint16 protocol = ppp_proto(buf);
        const guint8 *packet = ppp_info(buf);
 
-       /*
-        * Any non-LCP packets received during Link Establishment
-        * phase must be silently discarded.
-        */
-       if (ppp->phase == PPP_PHASE_ESTABLISHMENT && protocol != LCP_PROTOCOL)
+       if (ppp_drop_packet(ppp, protocol))
                return;
 
        switch (protocol) {
        case PPP_IP_PROTO:
-               /* If network is up & open, process the packet, if not, drop */
-               if (ppp->net)
-                       ppp_net_process_packet(ppp->net, packet);
+               ppp_net_process_packet(ppp->net, packet);
                break;
        case LCP_PROTOCOL:
                pppcp_process_packet(ppp->lcp, packet);