diff --git a/sys/net/sixlowpan/sixlownd.c b/sys/net/sixlowpan/sixlownd.c
index 82b9db5dcd..680587ff68 100644
--- a/sys/net/sixlowpan/sixlownd.c
+++ b/sys/net/sixlowpan/sixlownd.c
@@ -1138,10 +1138,11 @@ void def_rtr_lst_rem(def_rtr_lst_t *entry){
 //------------------------------------------------------------------------------
 // prefix list functions
 
-void plist_add(ipv6_addr_t *addr, uint8_t size, uint32_t val_ltime,
+plist_t *plist_add(ipv6_addr_t *addr, uint8_t size, uint32_t val_ltime,
              uint32_t pref_ltime, uint8_t adv_opt, uint8_t l_a_reserved1){
     if(prefix_count == OPT_PI_LIST_LEN){
         printf("ERROR: prefix list full\n");
+        return NULL;
     } else {
         plist[prefix_count].inuse = 1;
         plist[prefix_count].length = size;
@@ -1151,6 +1152,6 @@ void plist_add(ipv6_addr_t *addr, uint8_t size, uint32_t val_ltime,
         plist[prefix_count].pref_ltime = HTONL(pref_ltime);
         memcpy(&(plist[prefix_count].addr.uint8[0]), &(addr->uint8[0]), 16);
 
-        prefix_count++;
+        return &(plist[prefix_count++]);
     }
 }
diff --git a/sys/net/sixlowpan/sixlownd.h b/sys/net/sixlowpan/sixlownd.h
index 2418837c30..55c9b41ca1 100644
--- a/sys/net/sixlowpan/sixlownd.h
+++ b/sys/net/sixlowpan/sixlownd.h
@@ -218,7 +218,7 @@ void init_rtr_adv(ipv6_addr_t *addr, uint8_t sllao, uint8_t mtu, uint8_t pi,
                   uint8_t sixco, uint8_t abro);
 uint8_t plist_search(ipv6_addr_t *addr);
 uint8_t plist_cmp(ipv6_addr_t *addr1, ipv6_addr_t *addr2);
-void plist_add(ipv6_addr_t *addr, uint8_t size, uint32_t val_ltime,
+plist_t *plist_add(ipv6_addr_t *addr, uint8_t size, uint32_t val_ltime,
              uint32_t pref_ltime, uint8_t adv_opt, uint8_t l_a_reserved1);
 void set_llao(opt_stllao_t *sllao, uint8_t type, uint8_t length);
 abr_cache_t *abr_update_cache(
@@ -240,7 +240,5 @@ void init_nbr_sol(ipv6_addr_t *src, ipv6_addr_t *dest, ipv6_addr_t *targ,
                   uint8_t slloa, uint8_t aro);
 void init_nbr_adv(ipv6_addr_t *src, ipv6_addr_t *dst, ipv6_addr_t *tgt, 
                   uint8_t rso, uint8_t sllao, uint8_t aro, uint8_t aro_state);
-void plist_add(ipv6_addr_t *addr, uint8_t size, uint32_t val_ltime,
-             uint32_t pref_ltime, uint8_t adv_opt, uint8_t l_a_reserved1);
 void recv_nbr_sol(void);
 #endif /* SIXLOWND_H*/