From f2425961b7b7ae73a988f122a3c249a4681b4373 Mon Sep 17 00:00:00 2001
From: Martine Lenders <mlenders@inf.fu-berlin.de>
Date: Thu, 16 Apr 2015 18:26:03 +0200
Subject: [PATCH] [SQUASH ME] ng_ipv6: some adaptions

---
 sys/net/network_layer/ng_ipv6/ng_ipv6.c | 48 ++++++++++++++++---------
 1 file changed, 31 insertions(+), 17 deletions(-)

diff --git a/sys/net/network_layer/ng_ipv6/ng_ipv6.c b/sys/net/network_layer/ng_ipv6/ng_ipv6.c
index ec9324f717ab..fca4be25c387 100644
--- a/sys/net/network_layer/ng_ipv6/ng_ipv6.c
+++ b/sys/net/network_layer/ng_ipv6/ng_ipv6.c
@@ -153,9 +153,7 @@ static void _ipv6_send_unicast(kernel_pid_t iface, uint8_t *dst_l2addr,
          * is long enough and only then to throw away the header. This causes
          * to much overhead IMHO */
         DEBUG("ipv6: removed old interface header\n");
-        netif = pkt;
-        LL_DELETE(pkt, netif);
-        ng_pktbuf_release(netif);
+        pkt = ng_pktbuf_remove_snip(pkt, pkt);
     }
 
     DEBUG("ipv6: add to interface header to packet\n");
@@ -300,7 +298,7 @@ static void _ipv6_send_multicast(kernel_pid_t iface, ng_pktsnip_t *pkt,
 
             DEBUG("ipv6: send multicast over interface %" PRIkernel_pid "\n", ifs[i]);
             /* mark as multicast */
-            ((ng_netif_hdr_t *)pkt->data)->flags |= NG_NETIF_HDR_FLAGS_MULTICAST;
+            ((ng_netif_hdr_t *)netif->data)->flags |= NG_NETIF_HDR_FLAGS_MULTICAST;
             /* and send to interface */
             ng_netapi_send(iface, pkt);
         }
@@ -421,26 +419,42 @@ static void _ipv6_receive(kernel_pid_t iface, ng_pktsnip_t *pkt)
     LL_SEARCH_SCALAR(pkt, payload, type, NG_NETTYPE_IPV6);
 
     /* is it a valid IPv6 packet? */
-    if (!ng_ipv6_hdr_is_ipv6_hdr(payload->data)) {
-        DEBUG("ipv6: Received packet was not IPv6, dropping packet\n");
-        ng_pktbuf_release(pkt);
-        return;
-    }
-
-    payload = _start_write(payload);
 
     if (payload == NULL) {
         DEBUG("ipv6: unable to get write access to packet, dropping packet\n");
         return;
     }
 
-    ipv6 = ng_pktbuf_add(payload, payload->data, sizeof(ng_ipv6_hdr_t),
-                         NG_NETTYPE_IPV6);
+    if ((payload->next != NULL) && (payload->next->type == NG_NETTYPE_IPV6) &&
+        (payload->next->size == sizeof(ng_ipv6_hdr_t))) {
+        /* IP header was already marked. Take it. */
+        ipv6 = payload->next->data;
 
-    if (ipv6 == NULL) {
-        DEBUG("ipv6: error marking IPv6 header, dropping packet\n");
-        ng_pktbuf_release(pkt);
-        return;
+        if (!ng_ipv6_hdr_is_ipv6_hdr(ipv6->data)) {
+            DEBUG("ipv6: Received packet was not IPv6, dropping packet\n");
+            ng_pktbuf_release(pkt);
+            return;
+        }
+
+        payload = _start_write(payload);
+    }
+    else {
+        if (!ng_ipv6_hdr_is_ipv6_hdr(payload->data)) {
+            DEBUG("ipv6: Received packet was not IPv6, dropping packet\n");
+            ng_pktbuf_release(pkt);
+            return;
+        }
+
+        payload = _start_write(payload);
+
+        ipv6 = ng_pktbuf_add(payload, payload->data, sizeof(ng_ipv6_hdr_t),
+                             NG_NETTYPE_IPV6);
+
+        if (ipv6 == NULL) {
+            DEBUG("ipv6: error marking IPv6 header, dropping packet\n");
+            ng_pktbuf_release(pkt);
+            return;
+        }
     }
 
     /* extract header */