framer-802154: Support for explicit keys

core/net/llsec/llsec802154.h

@@ -69,6 +69,12 @@
 #define LLSEC802154_USES_ENCRYPTION    (LLSEC802154_SECURITY_LEVEL & (1 << 2))
 #endif /* LLSEC802154_CONF_USES_ENCRYPTION */
 
+#ifdef LLSEC802154_CONF_USES_EXPLICIT_KEYS
+#define LLSEC802154_USES_EXPLICIT_KEYS LLSEC802154_CONF_USES_EXPLICIT_KEYS
+#else /* LLSEC802154_CONF_USES_EXPLICIT_KEYS */
+#define LLSEC802154_USES_EXPLICIT_KEYS 0
+#endif /* LLSEC802154_CONF_USES_EXPLICIT_KEYS */
+
 #endif /* LLSEC802154_H_ */
 
 /** @} */

core/net/mac/frame802154.c

@@ -92,6 +92,23 @@ addr_len(uint8_t mode)
   }
 }
 /*----------------------------------------------------------------------------*/
+#if LLSEC802154_USES_EXPLICIT_KEYS
+static uint8_t
+get_key_id_len(uint8_t key_id_mode)
+{
+  switch(key_id_mode) {
+  case FRAME802154_1_BYTE_KEY_ID_MODE:
+    return 1;
+  case FRAME802154_5_BYTE_KEY_ID_MODE:
+    return 5;
+  case FRAME802154_9_BYTE_KEY_ID_MODE:
+    return 9;
+  default:
+    return 0;
+  }
+}
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
+/*----------------------------------------------------------------------------*/
 static void
 field_len(frame802154_t *p, field_length_t *flen)
 {
@@ -124,26 +141,11 @@ field_len(frame802154_t *p, field_length_t *flen)
 #if LLSEC802154_SECURITY_LEVEL
   /* Aux security header */
   if(p->fcf.security_enabled & 1) {
-    flen->aux_sec_len = 5;
+    flen->aux_sec_len = 5
-    /* TODO Support key identifier mode !=0 */
+#if LLSEC802154_USES_EXPLICIT_KEYS
-#if 0
+        + get_key_id_len(p->aux_hdr.security_control.key_id_mode);
-    switch(p->aux_hdr.security_control.key_id_mode) {
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
-    case 0:
+    ;
-      flen->aux_sec_len = 5; /* minimum value */
-      break;
-    case 1:
-      flen->aux_sec_len = 6;
-      break;
-    case 2:
-      flen->aux_sec_len = 10;
-      break;
-    case 3:
-      flen->aux_sec_len = 14;
-      break;
-    default:
-      break;
-    }
-#endif
   }
 #endif /* LLSEC802154_SECURITY_LEVEL */
 }
@@ -183,6 +185,9 @@ frame802154_create(frame802154_t *p, uint8_t *buf)
   int c;
   field_length_t flen;
   uint8_t pos;
+#if LLSEC802154_USES_EXPLICIT_KEYS
+  uint8_t key_id_mode;
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
 
   field_len(p, &flen);
   
@@ -226,10 +231,23 @@ frame802154_create(frame802154_t *p, uint8_t *buf)
 #if LLSEC802154_SECURITY_LEVEL
   /* Aux header */
   if(flen.aux_sec_len) {
-    /* TODO Support key identifier mode !=0 */
+    buf[pos++] = p->aux_hdr.security_control.security_level
-    buf[pos++] = p->aux_hdr.security_control.security_level;
+#if LLSEC802154_USES_EXPLICIT_KEYS
+        | (p->aux_hdr.security_control.key_id_mode << 3)
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
+    ;
     memcpy(buf + pos, p->aux_hdr.frame_counter.u8, 4);
     pos += 4;
+
+#if LLSEC802154_USES_EXPLICIT_KEYS
+    key_id_mode = p->aux_hdr.security_control.key_id_mode;
+    if(key_id_mode) {
+      c = (key_id_mode - 1) * 4;
+      memcpy(buf + pos, p->aux_hdr.key_source.u8, c);
+      pos += c;
+      buf[pos++] = p->aux_hdr.key_index;
+    }
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
   }
 #endif /* LLSEC802154_SECURITY_LEVEL */
 
@@ -251,6 +269,9 @@ frame802154_parse(uint8_t *data, int len, frame802154_t *pf)
   uint8_t *p;
   frame802154_fcf_t fcf;
   int c;
+#if LLSEC802154_USES_EXPLICIT_KEYS
+  uint8_t key_id_mode;
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
 
   if(len < 3) {
     return 0;
@@ -333,20 +354,28 @@ frame802154_parse(uint8_t *data, int len, frame802154_t *pf)
     linkaddr_copy((linkaddr_t *)&(pf->src_addr), &linkaddr_null);
     pf->src_pid = 0;
   }
-
+  
 #if LLSEC802154_SECURITY_LEVEL
   if(fcf.security_enabled) {
     pf->aux_hdr.security_control.security_level = p[0] & 7;
+#if LLSEC802154_USES_EXPLICIT_KEYS
     pf->aux_hdr.security_control.key_id_mode = (p[0] >> 3) & 3;
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
     p += 1;
     
     memcpy(pf->aux_hdr.frame_counter.u8, p, 4);
     p += 4;
-        
+    
-    if(pf->aux_hdr.security_control.key_id_mode) {
+#if LLSEC802154_USES_EXPLICIT_KEYS
-      /* TODO Support key identifier mode !=0 */
+    key_id_mode = pf->aux_hdr.security_control.key_id_mode;
-      return 0;
+    if(key_id_mode) {
+      c = (key_id_mode - 1) * 4;
+      memcpy(pf->aux_hdr.key_source.u8, p, c);
+      p += c;
+      pf->aux_hdr.key_index = p[0];
+      p += 1;
     }
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
   }
 #endif /* LLSEC802154_SECURITY_LEVEL */
 

core/net/mac/frame802154.h

@@ -105,6 +105,11 @@
 #define FRAME802154_SECURITY_LEVEL_ENC_MIC_64  (6)
 #define FRAME802154_SECURITY_LEVEL_ENC_MIC_128 (7)
 
+#define FRAME802154_IMPLICIT_KEY               (0)
+#define FRAME802154_1_BYTE_KEY_ID_MODE         (1)
+#define FRAME802154_5_BYTE_KEY_ID_MODE         (2)
+#define FRAME802154_9_BYTE_KEY_ID_MODE         (3)
+
 /**
  *    @brief  The IEEE 802.15.4 frame has a number of constant/fixed fields that
  *            can be counted to make frame construction and max payload
@@ -146,11 +151,17 @@ typedef union {
   uint8_t u8[4];
 } frame802154_frame_counter_t;
 
+typedef union {
+  uint16_t u16[4];
+  uint8_t u8[8];
+} frame802154_key_source_t;
+
 /** \brief 802.15.4 Aux security header */
 typedef struct {
-  frame802154_scf_t security_control;  /**< Security control bitfield */
+  frame802154_scf_t security_control;        /**< Security control bitfield */
-  frame802154_frame_counter_t frame_counter;   /**< Frame counter, used for security */
+  frame802154_frame_counter_t frame_counter; /**< Frame counter, used for security */
-  uint8_t  key[9];          /**< The key itself, or an index to the key */
+  frame802154_key_source_t key_source;       /**< Key Source subfield */
+  uint8_t key_index;                         /**< Key Index subfield */
 } frame802154_aux_hdr_t;
 
 /** \brief Parameters used by the frame802154_create() function.  These

core/net/mac/framer-802154.c

@@ -122,6 +122,11 @@ create_frame(int type, int do_create)
   params.aux_hdr.security_control.security_level = packetbuf_attr(PACKETBUF_ATTR_SECURITY_LEVEL);
   params.aux_hdr.frame_counter.u16[0] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1);
   params.aux_hdr.frame_counter.u16[1] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3);
+#if LLSEC802154_USES_EXPLICIT_KEYS
+  params.aux_hdr.security_control.key_id_mode = packetbuf_attr(PACKETBUF_ATTR_KEY_ID_MODE);
+  params.aux_hdr.key_index = packetbuf_attr(PACKETBUF_ATTR_KEY_INDEX);
+  params.aux_hdr.key_source.u16[0] = packetbuf_attr(PACKETBUF_ATTR_KEY_SOURCE_BYTES_0_1);
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
 #endif /* LLSEC802154_SECURITY_LEVEL */
 
   /* Increment and set the data sequence number. */
@@ -245,10 +250,16 @@ parse(void)
     packetbuf_set_attr(PACKETBUF_ATTR_PACKET_ID, frame.seq);
     
 #if LLSEC802154_SECURITY_LEVEL
-    /* Setting security-related attributes */
+    if(frame.fcf.security_enabled) {
-    packetbuf_set_attr(PACKETBUF_ATTR_SECURITY_LEVEL, frame.aux_hdr.security_control.security_level);
+      packetbuf_set_attr(PACKETBUF_ATTR_SECURITY_LEVEL, frame.aux_hdr.security_control.security_level);
-    packetbuf_set_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1, frame.aux_hdr.frame_counter.u16[0]);
+      packetbuf_set_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1, frame.aux_hdr.frame_counter.u16[0]);
-    packetbuf_set_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3, frame.aux_hdr.frame_counter.u16[1]);
+      packetbuf_set_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3, frame.aux_hdr.frame_counter.u16[1]);
+#if LLSEC802154_USES_EXPLICIT_KEYS
+      packetbuf_set_attr(PACKETBUF_ATTR_KEY_ID_MODE, frame.aux_hdr.security_control.key_id_mode);
+      packetbuf_set_attr(PACKETBUF_ATTR_KEY_INDEX, frame.aux_hdr.key_index);
+      packetbuf_set_attr(PACKETBUF_ATTR_KEY_SOURCE_BYTES_0_1, frame.aux_hdr.key_source.u16[0]);
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
+    }
 #endif /* LLSEC802154_SECURITY_LEVEL */
 
     PRINTF("15.4-IN: %2X", frame.fcf.frame_type);

core/net/packetbuf.h

@@ -362,6 +362,11 @@ enum {
   PACKETBUF_ATTR_SECURITY_LEVEL,
   PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1,
   PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3,
+#if LLSEC802154_USES_EXPLICIT_KEYS
+  PACKETBUF_ATTR_KEY_ID_MODE,
+  PACKETBUF_ATTR_KEY_INDEX,
+  PACKETBUF_ATTR_KEY_SOURCE_BYTES_0_1,
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
 #endif /* LLSEC802154_SECURITY_LEVEL */
   
   /* Scope 2 attributes: used between end-to-end nodes. */
@@ -389,6 +394,15 @@ enum {
 };
 #endif /* LLSEC802154_SECURITY_LEVEL */
 
+/* Define surrogates when not using explicit keys */
+#if !LLSEC802154_USES_EXPLICIT_KEYS
+enum {
+  PACKETBUF_ATTR_KEY_ID_MODE,
+  PACKETBUF_ATTR_KEY_INDEX,
+  PACKETBUF_ATTR_KEY_SOURCE_BYTES_0_1
+};
+#endif /* LLSEC802154_USES_EXPLICIT_KEYS */
+
 #define PACKETBUF_NUM_ADDRS 4
 #define PACKETBUF_NUM_ATTRS (PACKETBUF_ATTR_MAX - PACKETBUF_NUM_ADDRS)
 #define PACKETBUF_ADDR_FIRST PACKETBUF_ADDR_SENDER