Check FCS while unstuffing the byte stream

diff --git a/gatchat/ppp.c b/gatchat/ppp.c
index 6312dab..887a630 100644 (file)
--- a/gatchat/ppp.c
+++ b/gatchat/ppp.c
@@ -217,9 +217,8 @@ static void ppp_recv(GAtPPP *ppp, struct frame_buffer *frame)
 static struct frame_buffer *ppp_decode(GAtPPP *ppp, guint8 *frame)
 {
        guint8 *data;
-       guint pos = 0;
-       int i = 0;
-       int len;
+       guint pos;
+       int i;
        guint16 fcs;
        struct frame_buffer *fb;
 
@@ -229,7 +228,10 @@ static struct frame_buffer *ppp_decode(GAtPPP *ppp, guint8 *frame)
        data = fb->bytes;
 
        /* skip the first flag char */
-       pos++;
+       pos = 1;
+
+       fcs = PPPINITFCS16;
+       i = 0;
 
        /* TBD - how to deal with recv_accm */
        while (frame[pos] != PPP_FLAG_SEQ) {
@@ -240,21 +242,20 @@ static struct frame_buffer *ppp_decode(GAtPPP *ppp, guint8 *frame)
                        data[i] = frame[pos] ^ 0x20;
                } else
                        data[i] = frame[pos];
+
+               fcs = ppp_fcs(fcs, data[i]);
+
                i++; pos++;
        }
 
-       len = i;
-       fb->len = len;
+       fb->len = i;
 
        /* see if we have a good FCS */
-       fcs = PPPINITFCS16;
-       for (i = 0; i < len; i++)
-               fcs = ppp_fcs(fcs, data[i]);
-
        if (fcs != PPPGOODFCS16) {
                g_free(fb);
                return NULL;
        }
+
        return fb;
 }