decode: add PacketSetData funtion

This patch adds a function which can be used to set the payload
of a packet when a zero copy mode is used.

src/decode.c

@@ -345,6 +345,27 @@ inline int PacketCopyData(Packet *p, uint8_t *pktdata, int pktlen)
     SET_PKT_LEN(p, (size_t)pktlen);
     return PacketCopyDataOffset(p, 0, pktdata, pktlen);
 }
+
+
+/**
+ * \brief Set data for Packet and set length when zeo copy is used
+ *
+ *  \param Pointer to the Packet to modify
+ *  \param Pointer to the data
+ *  \param Length of the data
+ */
+inline int PacketSetData(Packet *p, uint8_t *pktdata, int pktlen)
+{
+    SET_PKT_LEN(p, (size_t)pktlen);
+    if (!pktdata) {
+        return -1;
+    }
+    p->ext_pkt = pktdata;
+    p->flags |= PKT_ZERO_COPY;
+
+    return 0;
+}
+
 /**
  * @}
  */

src/decode.h

@@ -777,6 +777,7 @@ Packet *PacketPseudoPktSetup(Packet *parent, uint8_t *pkt, uint16_t len, uint8_t
 Packet *PacketGetFromQueueOrAlloc(void);
 Packet *PacketGetFromAlloc(void);
 int PacketCopyData(Packet *p, uint8_t *pktdata, int pktlen);
+int PacketSetData(Packet *p, uint8_t *pktdata, int pktlen);
 int PacketCopyDataOffset(Packet *p, int offset, uint8_t *data, int datalen);
 
 DecodeThreadVars *DecodeThreadVarsAlloc();