[PATCH] ppp: silently discard packets if needed

[Kristen Carlson Accardi]

When receiving a packet, check the protocol and the phase to see
if the packet should be dropped.
---
 gatchat/gatppp.c |   31 ++++++++++++++++++++++++++-----
 1 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/gatchat/gatppp.c b/gatchat/gatppp.c
index c7bf089..933cbec 100644
--- a/gatchat/gatppp.c
+++ b/gatchat/gatppp.c
@@ -173,17 +173,38 @@ static struct frame_buffer *ppp_encode(GAtPPP *ppp, guint8 *data, int len)
 	return fb;
 }
 
+/*
+ * Silently discard packets which are received when they shouldn't be
+ */
+static inline gboolean 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;
+		break;
+	case PPP_PHASE_NETWORK:
+		break;
+	}
+
+	return FALSE;
+}
+
 /* called when we have received a complete ppp frame */
 static void ppp_recv(GAtPPP *ppp, struct frame_buffer *frame)
 {
 	guint16 protocol = ppp_proto(frame->bytes);
 	guint8 *packet = ppp_info(frame->bytes);
 
-	/*
-	 * Any non-LCP packets received during Link Establishment
-	 * phase must be silently discarded.
-	 */
-	if (ppp->phase == PPP_PHASE_ESTABLISHMENT && protocol != LCP_PROTOCOL)
+	if (drop_packet(ppp, protocol))
 		return;
 
 	switch (protocol) {
-- 
1.6.6.1