netreg: add multiplexer for header building

sys/include/net/ng_netreg.h

@@ -24,6 +24,7 @@
 
 #include "kernel_types.h"
 #include "net/ng_nettype.h"
+#include "net/ng_pkt.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -126,6 +127,25 @@ int ng_netreg_num(ng_nettype_t type, uint32_t demux_ctx);
  */
 ng_netreg_entry_t *ng_netreg_getnext(ng_netreg_entry_t *entry);
 
+/**
+ * @brief   Builds a header for sending and adds it to the packet buffer.
+ *
+ * @param[in] type      Type of the header.
+ * @param[in] payload   Payload for the packet.
+ * @param[in] src       Source address for the header. Can be NULL if not
+ *                      known or required.
+ * @param[in] src_len   Length of @p src. Can be 0 if not known or required.
+ * @param[in] dst       Destination address for the header. Can be NULL if not
+ *                      known or required.
+ * @param[in] dst_len   Length of @p dst. Can be 0 if not known or required.
+ *
+ * @return  The header for the protocol on success.
+ * @return  NULL on error.
+ */
+ng_pktsnip_t *ng_netreg_hdr_build(ng_nettype_t type, ng_pktsnip_t *payload,
+                                  uint8_t *src, uint8_t src_len,
+                                  uint8_t *dst, uint8_t dst_len);
+
 #ifdef __cplusplus
 }
 #endif

sys/net/crosslayer/ng_netreg/ng_netreg.c

@@ -19,6 +19,7 @@
 #include "utlist.h"
 #include "net/ng_netreg.h"
 #include "net/ng_nettype.h"
+#include "net/ng_ipv6.h"
 
 #define _INVALID_TYPE(type) (((type) < NG_NETTYPE_UNDEF) || ((type) >= NG_NETTYPE_NUMOF))
 
@@ -101,4 +102,30 @@ ng_netreg_entry_t *ng_netreg_getnext(ng_netreg_entry_t *entry)
     return entry;
 }
 
+ng_pktsnip_t *ng_netreg_hdr_build(ng_nettype_t type, ng_pktsnip_t *payload,
+                                  uint8_t *src, uint8_t src_len,
+                                  uint8_t *dst, uint8_t dst_len)
+{
+    switch (type) {
+#ifdef MODULE_NG_IPV6
+
+        case NG_NETTYPE_IPV6:
+            return ng_ipv6_hdr_build(payload, src, src_len, dst, dst_len);
+#endif
+#ifdef MODULE_NG_TCP
+
+        case NG_NETTYPE_TCP:
+            return ng_tcp_hdr_build(payload, src, src_len, dst, dst_len);
+#endif
+#ifdef MODULE_NG_UDP
+
+        case NG_NETTYPE_UDP:
+            return ng_udp_hdr_build(payload, src, src_len, dst, dst_len);
+#endif
+
+        default:
+            return NULL;
+    }
+}
+
 /** @} */