pdu: fix MAC RAR PDU packing and unpacking with backoff indicator

lib/include/srslte/common/pdu.h

@@ -338,12 +338,15 @@ public:
 class rar_subh : public subh<rar_subh>
 {
 public:
+  typedef enum { BACKOFF = 0, RAPID } rar_subh_type_t;
+
   rar_subh() {
     bzero(&grant, sizeof(grant));
     ta        = 0;
     temp_rnti = 0;
     preamble  = 0;
     parent    = NULL;
+    type      = BACKOFF;
   }
 
   static const uint32_t RAR_GRANT_LEN = 20; 
@@ -351,6 +354,7 @@ public:
   // Reading functions
   bool     read_subheader(uint8_t** ptr);
   void     read_payload(uint8_t** ptr);
+  bool     has_rapid();
   uint32_t get_rapid();
   uint32_t get_ta_cmd();
   uint16_t get_temp_crnti();
@@ -372,6 +376,7 @@ private:
   uint32_t ta; 
   uint16_t temp_rnti; 
   uint32_t preamble;
+  rar_subh_type_t type;
 };
 
 class rar_pdu : public pdu<rar_subh>
@@ -390,7 +395,6 @@ public:
 private:
   bool       has_backoff_indicator;
   uint8_t    backoff_indicator;
-
 };
 
 class mch_subh : public sch_subh

lib/src/common/pdu.cc

@@ -826,9 +826,6 @@ uint8_t sch_subh::phr_report_table(float phr_value)
 void rar_pdu::fprint(FILE* stream)
 {
   fprintf(stream, "MAC PDU for RAR. ");
-  if (has_backoff_indicator) {
-    fprintf(stream, "Backoff Indicator %d. ", backoff_indicator);
-  }
   pdu::fprint(stream);  
 } 
 
@@ -861,7 +858,7 @@ bool rar_pdu::write_packet(uint8_t* ptr)
   if (has_backoff_indicator) {
     *(ptr) = backoff_indicator&0xf;
     if (nof_subheaders > 0) {
-      *(ptr) = 1<<7;
+      *(ptr) |= 1 << 7;
     }
     ptr++;
   }
@@ -882,7 +879,12 @@ bool rar_pdu::write_packet(uint8_t* ptr)
 
 void rar_subh::fprint(FILE* stream)
 {
+  if (type == RAPID) {
     fprintf(stream, "RAPID: %d, Temp C-RNTI: %d, TA: %d, UL Grant: ", preamble, temp_rnti, ta);
+  } else {
+    fprintf(stream, "Backoff Indicator %d. ", ((rar_pdu*)parent)->get_backoff());
+  }
+
   srslte_vec_fprint_hex(stream, grant, 20);
 }
 
@@ -898,6 +900,11 @@ uint32_t rar_subh::get_rapid()
   return preamble; 
 }
 
+bool rar_subh::has_rapid()
+{
+  return (type == RAPID);
+}
+
 void rar_subh::get_sched_grant(uint8_t grant_[RAR_GRANT_LEN])
 {
   memcpy(grant_, grant, sizeof(uint8_t)*RAR_GRANT_LEN);
@@ -954,6 +961,7 @@ void rar_subh::write_payload(uint8_t** ptr)
 
 void rar_subh::read_payload(uint8_t** ptr)
 {
+  if (type == RAPID) {
     ta         = ((uint32_t) * (*ptr + 0) & 0x7f) << 4 | (*(*ptr + 1) & 0xf0) >> 4;
     grant[0]   = *(*ptr + 1) & 0x8 ? 1 : 0;
     grant[1]   = *(*ptr + 1) & 0x4 ? 1 : 0;
@@ -965,12 +973,13 @@ void rar_subh::read_payload(uint8_t** ptr)
     temp_rnti = ((uint16_t) * (*ptr + 4)) << 8 | *(*ptr + 5);
     *ptr += 6;
   }
+}
 
 bool rar_subh::read_subheader(uint8_t** ptr)
 {
   bool e_bit = *(*ptr) & 0x80?true:false;
-  bool type  = *(*ptr) & 0x40?true:false;
-  if (type) {
+  type       = *(*ptr) & 0x40 ? RAPID : BACKOFF;
+  if (type == RAPID) {
     preamble = *(*ptr) & 0x3f;
   } else {
     ((rar_pdu*)parent)->set_backoff(*(*ptr) & 0xf);