From 2ac91d53b573de66e6d473f0a8a74ea8ccc5e013 Mon Sep 17 00:00:00 2001
From: Vincent Brillault <vincent.brillault@imag.fr>
Date: Mon, 11 Jul 2011 14:19:14 +0200
Subject: [PATCH] Add (dangerous) feature : use layer 2 acks instead of NUD in
 the IPv6 layer. (Decrease packet numbers but dangerous if neighbors change
 their ips (not a problem in standard RPL with EUI-64 based addresses))

---
 core/net/neighbor-info.c | 20 ++++++++++++++++++++
 core/net/uip-ds6.c       | 18 ++++++++++++++++++
 core/net/uip-ds6.h       |  8 ++++++++
 3 files changed, 46 insertions(+)

diff --git a/core/net/neighbor-info.c b/core/net/neighbor-info.c
index c36a2b8a5..f704073a1 100644
--- a/core/net/neighbor-info.c
+++ b/core/net/neighbor-info.c
@@ -39,6 +39,8 @@
 
 #include "net/neighbor-info.h"
 #include "net/neighbor-attr.h"
+#include "net/uip-ds6.h"
+#include "net/uip-nd6.h"
 
 #define DEBUG DEBUG_NONE
 #include "net/uip-debug.h"
@@ -104,6 +106,9 @@ neighbor_info_packet_sent(int status, int numtx)
 {
   const rimeaddr_t *dest;
   link_metric_t packet_metric;
+#if UIP_DS6_LL_NUD
+  uip_ds6_nbr_t * nbr;
+#endif /* UIP_DS6_LL_NUD */
 
   dest = packetbuf_addr(PACKETBUF_ADDR_RECEIVER);
   if(rimeaddr_cmp(dest, &rimeaddr_null)) {
@@ -118,6 +123,21 @@ neighbor_info_packet_sent(int status, int numtx)
   case MAC_TX_OK:
     packet_metric = numtx;
     add_neighbor(dest);
+#if UIP_DS6_LL_NUD
+    nbr=uip_ds6_nbr_ll_lookup((uip_lladdr_t *) dest);
+    if (nbr!=NULL) {
+      PRINTF("neighbor-info : nbr state = %u\n",nbr->state);
+    } else {
+      PRINTF("neighbor-info : no nbr\n");
+    }
+    if (nbr!=NULL && (nbr->state == STALE || nbr->state == DELAY || nbr->state == PROBE)) {
+      nbr->state = REACHABLE;
+      stimer_set(&nbr->reachable, UIP_ND6_REACHABLE_TIME / 1000);
+      PRINTF("neighbor-info : received a linklayer ack : ");
+      PRINTLLADDR((uip_lladdr_t *)dest);
+      PRINTF(" is reachable.\n");
+    }
+#endif /* UIP_DS6_LL_NUD */
     break;
   case MAC_TX_COLLISION:
     packet_metric = numtx;
diff --git a/core/net/uip-ds6.c b/core/net/uip-ds6.c
index cea431612..6f11a5297 100644
--- a/core/net/uip-ds6.c
+++ b/core/net/uip-ds6.c
@@ -369,6 +369,24 @@ uip_ds6_nbr_lookup(uip_ipaddr_t *ipaddr)
   return NULL;
 }
 
+/*---------------------------------------------------------------------------*/
+uip_ds6_nbr_t *
+uip_ds6_nbr_ll_lookup(uip_lladdr_t *lladdr)
+{
+  uip_ds6_nbr_t *fin;
+
+  for( locnbr=uip_ds6_nbr_cache, fin=locnbr + UIP_DS6_NBR_NB;
+       locnbr<fin;
+       ++locnbr) {
+    if(locnbr->isused) {
+      if(!memcmp(lladdr,&locnbr->lladdr,UIP_LLADDR_LEN)) {
+        return locnbr;
+      }
+    }
+  }
+  return NULL;
+}
+
 /*---------------------------------------------------------------------------*/
 uip_ds6_defrt_t *
 uip_ds6_defrt_add(uip_ipaddr_t *ipaddr, unsigned long interval)
diff --git a/core/net/uip-ds6.h b/core/net/uip-ds6.h
index 3b31d8315..dc608ef16 100644
--- a/core/net/uip-ds6.h
+++ b/core/net/uip-ds6.h
@@ -124,6 +124,13 @@
 #endif
 #define UIP_DS6_AADDR_NB UIP_DS6_AADDR_NBS + UIP_DS6_AADDR_NBU
 
+/*--------------------------------------------------*/
+/* Should we use LinkLayer acks in NUD ?*/
+#ifndef UIP_CONF_DS6_LL_NUD
+#define UIP_DS6_LL_NUD 0
+#else
+#define UIP_DS6_LL_NUD UIP_CONF_DS6_LL_NUD
+#endif
 
 /*--------------------------------------------------*/
 /** \brief Possible states for the nbr cache entries */
@@ -312,6 +319,7 @@ uip_ds6_nbr_t *uip_ds6_nbr_add(uip_ipaddr_t *ipaddr, uip_lladdr_t *lladdr,
                                uint8_t isrouter, uint8_t state);
 void uip_ds6_nbr_rm(uip_ds6_nbr_t *nbr);
 uip_ds6_nbr_t *uip_ds6_nbr_lookup(uip_ipaddr_t *ipaddr);
+uip_ds6_nbr_t *uip_ds6_nbr_ll_lookup(uip_lladdr_t *lladdr);
 
 /** @} */