From 0580fa5852cee45738d81e2cee958c9c641f808a Mon Sep 17 00:00:00 2001
From: Martine Lenders <m.lenders@fu-berlin.de>
Date: Wed, 24 Oct 2018 18:03:39 +0200
Subject: [PATCH] gnrc_ipv6: dispatch ext. headers to external interested
 parties

This way e.g. a raw socket listening for an extension headers protocol
number also get's it.
---
 sys/include/net/gnrc/ipv6/ext.h               |  3 +++
 .../network_layer/ipv6/ext/gnrc_ipv6_ext.c    | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/sys/include/net/gnrc/ipv6/ext.h b/sys/include/net/gnrc/ipv6/ext.h
index 2c61e4e39b..b03d9c7843 100644
--- a/sys/include/net/gnrc/ipv6/ext.h
+++ b/sys/include/net/gnrc/ipv6/ext.h
@@ -41,6 +41,9 @@ extern "C" {
 /**
  * @brief   Demultiplex an extension header according to @p nh.
  *
+ * This includes dispatching it to interested parties in the
+ * @ref net_gnrc_netreg.
+ *
  * @param[in] pkt       A packet with the first snip pointing to the extension
  *                      header to process.
  * @param[in] nh        Protocol number of @p pkt.
diff --git a/sys/net/gnrc/network_layer/ipv6/ext/gnrc_ipv6_ext.c b/sys/net/gnrc/network_layer/ipv6/ext/gnrc_ipv6_ext.c
index 74bd79b569..0130414fb9 100644
--- a/sys/net/gnrc/network_layer/ipv6/ext/gnrc_ipv6_ext.c
+++ b/sys/net/gnrc/network_layer/ipv6/ext/gnrc_ipv6_ext.c
@@ -19,6 +19,7 @@
 
 #include "utlist.h"
 #include "net/gnrc/netif.h"
+#include "net/gnrc/netreg.h"
 #include "net/gnrc/pktbuf.h"
 #include "net/gnrc/icmpv6/error.h"
 #include "net/gnrc/ipv6.h"
@@ -258,6 +259,24 @@ gnrc_pktsnip_t *gnrc_ipv6_ext_demux(gnrc_pktsnip_t *pkt, unsigned nh)
         gnrc_pktbuf_release(pkt);
         return NULL;
     }
+    if (gnrc_netreg_num(GNRC_NETTYPE_IPV6, nh) > 0) {
+        gnrc_pktsnip_t *sub_pkt;
+
+        /* enforce duplication so we can dispatch packet to subscriber(s) and
+         * handle the packet */
+        gnrc_pktbuf_hold(pkt, 1);
+        sub_pkt = gnrc_pktbuf_start_write(pkt);
+        if (sub_pkt != NULL) {
+            /* check in case subscriber unregistered in the meantime */
+            if (gnrc_netapi_dispatch_receive(GNRC_NETTYPE_IPV6, nh, sub_pkt) == 0) {
+                gnrc_pktbuf_release(sub_pkt);
+            };
+        }
+        else {
+            gnrc_pktbuf_release(pkt);
+            /* try to keep handling, the sockets aren't *that* important anyway :-P */
+        }
+    }
     switch (nh) {
         case PROTNUM_IPV6_EXT_RH:
 #ifdef MODULE_GNRC_RPL_SRH