net: buf: Add net_buf_add_le32() helper API

The function gets 32bits wide data, converts host order to little
endian and then puts the data on protocol stack to be send.

Change-Id: I29e4040b302a16b551a0922133c327ff694fec5d
Signed-off-by: Arkadiusz Lichwa <arkadiusz.lichwa@tieto.com>

include/net/buf.h

@@ -204,6 +204,19 @@ uint8_t *net_buf_add_u8(struct net_buf *buf, uint8_t value);
  */
 void net_buf_add_le16(struct net_buf *buf, uint16_t value);
 
+/** @brief Add 32-bit value at the end of the buffer
+ *
+ *  Adds 32-bit value in little endian format at the end of buffer.
+ *  Increments the data length of a buffer to account for more data
+ *  at the end.
+ *
+ *  @param buf Buffer to update.
+ *  @param value 32-bit value to be added.
+ *
+ *  @return void
+ */
+void net_buf_add_le32(struct net_buf *buf, uint32_t value);
+
 /** @brief Push data to the beginning of the buffer.
  *
  *  Modifies the data pointer and buffer length to account for more data

net/buf.c

@@ -139,6 +139,14 @@ void net_buf_add_le16(struct net_buf *buf, uint16_t value)
 	memcpy(net_buf_add(buf, sizeof(value)), &value, sizeof(value));
 }
 
+void net_buf_add_le32(struct net_buf *buf, uint32_t value)
+{
+	NET_BUF_DBG("buf %p value %u\n", buf, value);
+
+	value = sys_cpu_to_le32(value);
+	memcpy(net_buf_add(buf, sizeof(value)), &value, sizeof(value));
+}
+
 void *net_buf_push(struct net_buf *buf, size_t len)
 {
 	NET_BUF_DBG("buf %p len %u\n", buf, len);