From a2b9defc8ba96e1d4cf92a1f2b6c594764b74ad9 Mon Sep 17 00:00:00 2001
From: Oleg Hahm <oleg@hobbykeller.org>
Date: Fri, 1 Apr 2016 21:47:06 +0200
Subject: [PATCH] gnrc ipv6: convenient function to get the header

---
 sys/include/net/gnrc/ipv6.h                 | 13 +++++++++++++
 sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c | 11 +++++++++++
 2 files changed, 24 insertions(+)

diff --git a/sys/include/net/gnrc/ipv6.h b/sys/include/net/gnrc/ipv6.h
index 03b89cb8aa..e736808e37 100644
--- a/sys/include/net/gnrc/ipv6.h
+++ b/sys/include/net/gnrc/ipv6.h
@@ -137,6 +137,19 @@ kernel_pid_t gnrc_ipv6_init(void);
  */
 void gnrc_ipv6_demux(kernel_pid_t iface, gnrc_pktsnip_t *current, gnrc_pktsnip_t *pkt, uint8_t nh);
 
+/**
+ * @brief   Get the IPv6 header from a given list of @ref gnrc_pktsnip_t
+ *
+ *          This function may be used with e.g. a pointer to a (full) UDP datagram.
+ *
+ * @param[in] pkt    The pointer to the first @ref gnrc_pktsnip_t of the
+ *                   packet.
+ *
+ * @return A pointer to the @ref ipv6_hdr_t of the packet.
+ * @return NULL if the packet does not contain an IPv6 header.
+ */
+ipv6_hdr_t *gnrc_ipv6_get_header(gnrc_pktsnip_t *pkt);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c b/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
index d608dcd3e8..8dcef2dbab 100644
--- a/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
+++ b/sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c
@@ -208,6 +208,17 @@ void gnrc_ipv6_demux(kernel_pid_t iface, gnrc_pktsnip_t *current, gnrc_pktsnip_t
     gnrc_pktbuf_release(pkt);
 }
 
+ipv6_hdr_t *gnrc_ipv6_get_header(gnrc_pktsnip_t *pkt)
+{
+    ipv6_hdr_t *hdr = NULL;
+    gnrc_pktsnip_t *tmp = gnrc_pktsnip_search_type(pkt, GNRC_NETTYPE_IPV6);
+    if ((tmp) && ipv6_hdr_is(tmp->data)) {
+        hdr = ((ipv6_hdr_t*) tmp->data);
+    }
+
+    return hdr;
+}
+
 /* internal functions */
 static void *_event_loop(void *args)
 {