From a53be5173377a3e8e1ca56144f010caa15bb7053 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Wed, 21 Jun 2017 09:17:47 -0600
Subject: [PATCH] 6LoWPAN: Correct an error in calculating the location of the
 UDP header.

---
 net/sixlowpan/sixlowpan_hc06.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/net/sixlowpan/sixlowpan_hc06.c b/net/sixlowpan/sixlowpan_hc06.c
index e066da19b5..c6681b2724 100644
--- a/net/sixlowpan/sixlowpan_hc06.c
+++ b/net/sixlowpan/sixlowpan_hc06.c
@@ -68,13 +68,6 @@
 
 #ifdef CONFIG_NET_6LOWPAN_COMPRESSION_HC06
 
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
-#define UDPIPv6BUF(ieee) \
-  ((FAR struct udp_hdr_s *)&((ieee)->i_dev.d_buf[IPv6_HDRLEN]))
-
 /****************************************************************************
  * Private Types
  ****************************************************************************/
@@ -760,9 +753,12 @@ void sixlowpan_compresshdr_hc06(FAR struct ieee802154_driver_s *ieee,
 
   if (ipv6->proto == IP_PROTO_UDP)
     {
-      FAR struct udp_hdr_s *udp = UDPIPv6BUF(ieee);
+      /* The UDP header will follow the IPv6 header */
 
-      ninfo("Uncompressed UDP ports on send side: %x, %x\n",
+      FAR struct udp_hdr_s *udp =
+        (FAR struct udp_hdr_s *)((FAR uint8_t *)ipv6 + IPv6_HDRLEN);
+
+      ninfo("Uncompressed UDP ports on send side: srcport=%04x destport=%04x\n",
             ntohs(udp->srcport), ntohs(udp->destport));
 
       /* Mask out the last 4 bits can be used as a mask */