From 9b6ba3c0090afd94f7141fc90b2d4b9e15f4f70f Mon Sep 17 00:00:00 2001
From: Laurent Deru <laurent.deru@cetic.be>
Date: Thu, 22 Dec 2016 09:00:38 +0100
Subject: [PATCH] Make frame fcf creation and parsing standalone functions

---
 core/net/mac/frame802154.c | 66 +++++++++++++++++++++++---------------
 core/net/mac/frame802154.h |  2 ++
 2 files changed, 42 insertions(+), 26 deletions(-)

diff --git a/core/net/mac/frame802154.c b/core/net/mac/frame802154.c
index c970cd964..d5c55c4e8 100644
--- a/core/net/mac/frame802154.c
+++ b/core/net/mac/frame802154.c
@@ -183,7 +183,7 @@ frame802154_has_panid(frame802154_fcf_t *fcf, int *has_src_pan_id, int *has_dest
   } else {
     /* No PAN ID in ACK */
     if(fcf->frame_type != FRAME802154_ACKFRAME) {
-      if(!fcf->panid_compression && fcf->src_addr_mode & 3) {
+      if(!fcf->panid_compression && (fcf->src_addr_mode & 3)) {
         /* If compressed, don't include source PAN ID */
         src_pan_id = 1;
       }
@@ -304,7 +304,7 @@ field_len(frame802154_t *p, field_length_t *flen)
    * up to the caller. */
   if(p->fcf.frame_version < FRAME802154_IEEE802154E_2012) {
     /* Set PAN ID compression bit if src pan id matches dest pan id. */
-    if(p->fcf.dest_addr_mode & 3 && p->fcf.src_addr_mode & 3 &&
+    if((p->fcf.dest_addr_mode & 3) && (p->fcf.src_addr_mode & 3) &&
        p->src_pid == p->dest_pid) {
       p->fcf.panid_compression = 1;
     } else {
@@ -362,6 +362,20 @@ frame802154_hdrlen(frame802154_t *p)
   return 2 + flen.seqno_len + flen.dest_pid_len + flen.dest_addr_len +
          flen.src_pid_len + flen.src_addr_len + flen.aux_sec_len;
 }
+void
+frame802154_create_fcf(frame802154_fcf_t *fcf, uint8_t *buf)
+{
+  buf[0] = (fcf->frame_type & 7) |
+    ((fcf->security_enabled & 1) << 3) |
+    ((fcf->frame_pending & 1) << 4) |
+    ((fcf->ack_required & 1) << 5) |
+    ((fcf->panid_compression & 1) << 6);
+  buf[1] = ((fcf->sequence_number_suppression & 1)) |
+    ((fcf->ie_list_present & 1)) << 1 |
+    ((fcf->dest_addr_mode & 3) << 2) |
+    ((fcf->frame_version & 3) << 4) |
+    ((fcf->src_addr_mode & 3) << 6);
+}
 /*----------------------------------------------------------------------------*/
 /**
  *   \brief Creates a frame for transmission over the air.  This function is
@@ -388,17 +402,7 @@ frame802154_create(frame802154_t *p, uint8_t *buf)
 
   /* OK, now we have field lengths.  Time to actually construct */
   /* the outgoing frame, and store it in buf */
-  buf[0] = (p->fcf.frame_type & 7) |
-    ((p->fcf.security_enabled & 1) << 3) |
-    ((p->fcf.frame_pending & 1) << 4) |
-    ((p->fcf.ack_required & 1) << 5) |
-    ((p->fcf.panid_compression & 1) << 6);
-  buf[1] = ((p->fcf.sequence_number_suppression & 1)) |
-    ((p->fcf.ie_list_present & 1)) << 1 |
-    ((p->fcf.dest_addr_mode & 3) << 2) |
-    ((p->fcf.frame_version & 3) << 4) |
-    ((p->fcf.src_addr_mode & 3) << 6);
-
+  frame802154_create_fcf(&p->fcf, buf);
   pos = 2;
 
   /* Sequence number */
@@ -460,6 +464,28 @@ frame802154_create(frame802154_t *p, uint8_t *buf)
 
   return (int)pos;
 }
+
+void
+frame802154_parse_fcf(uint8_t *data, frame802154_fcf_t *pfcf)
+{
+  frame802154_fcf_t fcf;
+
+  /* decode the FCF */
+  fcf.frame_type = data[0] & 7;
+  fcf.security_enabled = (data[0] >> 3) & 1;
+  fcf.frame_pending = (data[0] >> 4) & 1;
+  fcf.ack_required = (data[0] >> 5) & 1;
+  fcf.panid_compression = (data[0] >> 6) & 1;
+
+  fcf.sequence_number_suppression = data[1] & 1;
+  fcf.ie_list_present = (data[1] >> 1) & 1;
+  fcf.dest_addr_mode = (data[1] >> 2) & 3;
+  fcf.frame_version = (data[1] >> 4) & 3;
+  fcf.src_addr_mode = (data[1] >> 6) & 3;
+
+  /* copy fcf */
+  memcpy(pfcf, &fcf, sizeof(frame802154_fcf_t));
+}
 /*----------------------------------------------------------------------------*/
 /**
  *   \brief Parses an input frame.  Scans the input frame to find each
@@ -489,19 +515,7 @@ frame802154_parse(uint8_t *data, int len, frame802154_t *pf)
   p = data;
 
   /* decode the FCF */
-  fcf.frame_type = p[0] & 7;
-  fcf.security_enabled = (p[0] >> 3) & 1;
-  fcf.frame_pending = (p[0] >> 4) & 1;
-  fcf.ack_required = (p[0] >> 5) & 1;
-  fcf.panid_compression = (p[0] >> 6) & 1;
-
-  fcf.sequence_number_suppression = p[1] & 1;
-  fcf.ie_list_present = (p[1] >> 1) & 1;
-  fcf.dest_addr_mode = (p[1] >> 2) & 3;
-  fcf.frame_version = (p[1] >> 4) & 3;
-  fcf.src_addr_mode = (p[1] >> 6) & 3;
-
-  /* copy fcf and seqNum */
+  frame802154_parse_fcf(p, &fcf);
   memcpy(&pf->fcf, &fcf, sizeof(frame802154_fcf_t));
   p += 2;                             /* Skip first two bytes */
 
diff --git a/core/net/mac/frame802154.h b/core/net/mac/frame802154.h
index defb64b53..2ff067a26 100644
--- a/core/net/mac/frame802154.h
+++ b/core/net/mac/frame802154.h
@@ -207,8 +207,10 @@ typedef struct {
 /* Prototypes */
 
 int frame802154_hdrlen(frame802154_t *p);
+void frame802154_create_fcf(frame802154_fcf_t *fcf, uint8_t *buf);
 int frame802154_create(frame802154_t *p, uint8_t *buf);
 int frame802154_parse(uint8_t *data, int length, frame802154_t *pf);
+void frame802154_parse_fcf(uint8_t *data, frame802154_fcf_t *pfcf);
 
 /* Get current PAN ID */
 uint16_t frame802154_get_pan_id(void);