/* * Copyright (c) 2014-2015, Yanzi Networks AB. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the copyright holders nor the * names of its contributors may be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * */ /** * \addtogroup rpl-lite * @{ * * \file * * Default RPL NBR policy * decides when to add a new discovered node to the nbr table from RPL. * * \author Joakim Eriksson * Contributors: Niclas Finne , Oriol PiƱol , * */ #include "net/routing/rpl-lite/rpl.h" #include "net/nbr-table.h" /* Log configuration */ #include "sys/log.h" #define LOG_MODULE "RPL" #define LOG_LEVEL LOG_LEVEL_RPL /* * Policy for neighbor addition * - one node is locked (default route) * - max X "best parents" * => at least MAX_NBRS - (X + 1) free slots for other. * * NOTE: this policy assumes that all neighbors end up being IPv6 * neighbors and are not only MAC neighbors. */ #define UIP_IP_BUF ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN]) static int num_parents; /* all nodes that are possible parents */ static int num_free; static const linkaddr_t *worst_rank_nbr_lladdr; /* lladdr of the the neighbor with the worst rank */ static rpl_rank_t worst_rank; /*---------------------------------------------------------------------------*/ static void update_state(void) { uip_ds6_nbr_t *ds6_nbr; rpl_nbr_t *rpl_nbr; rpl_rank_t nbr_rank; int num_used = 0; worst_rank = 0; worst_rank_nbr_lladdr = NULL; num_parents = 0; ds6_nbr = uip_ds6_nbr_head(); while(ds6_nbr != NULL) { const linkaddr_t *nbr_lladdr = (const linkaddr_t *)uip_ds6_nbr_get_ll(ds6_nbr); rpl_nbr = rpl_neighbor_get_from_lladdr((uip_lladdr_t *)nbr_lladdr); if(rpl_nbr != NULL && rpl_neighbor_is_parent(rpl_nbr)) { num_parents++; } nbr_rank = rpl_neighbor_rank_via_nbr(rpl_nbr); /* Select worst-rank neighbor */ if(rpl_nbr != curr_instance.dag.preferred_parent && nbr_rank > worst_rank) { /* This is the worst-rank neighbor - this is a good candidate for removal */ worst_rank = nbr_rank; worst_rank_nbr_lladdr = nbr_lladdr; } ds6_nbr = uip_ds6_nbr_next(ds6_nbr); num_used++; } /* how many more IP neighbors can be have? */ num_free = NBR_TABLE_MAX_NEIGHBORS - num_used; LOG_DBG("nbr-policy: free: %d, parents: %d\n", num_free, num_parents); } /*---------------------------------------------------------------------------*/ static const linkaddr_t * find_worst_rank_nbr_lladdr(void) { update_state(); return worst_rank_nbr_lladdr; } /*---------------------------------------------------------------------------*/ static const linkaddr_t * find_removable_dio(uip_ipaddr_t *from, rpl_dio_t *dio) { update_state(); if(!curr_instance.used || curr_instance.instance_id != dio->instance_id) { LOG_WARN("nbr-policy: did not find instance id: %d\n", dio->instance_id); return NULL; } /* Add the new neighbor only if it is better than the current worst. */ if(dio->rank + curr_instance.min_hoprankinc < worst_rank - curr_instance.min_hoprankinc / 2) { /* Found *great* neighbor - add! */ LOG_DBG("nbr-policy: DIO rank %u, worst_rank %u -- add to cache\n", dio->rank, worst_rank); return worst_rank_nbr_lladdr; } LOG_DBG("nbr-policy: DIO rank %u, worst_rank %u -- do not add to cache\n", dio->rank, worst_rank); return NULL; } /*---------------------------------------------------------------------------*/ const linkaddr_t * rpl_nbr_policy_find_removable(nbr_table_reason_t reason, void *data) { /* When we get the DIO/DAO/DIS we know that UIP contains the incoming packet */ switch(reason) { case NBR_TABLE_REASON_RPL_DIO: return find_removable_dio(&UIP_IP_BUF->srcipaddr, data); case NBR_TABLE_REASON_RPL_DIS: return find_worst_rank_nbr_lladdr(); case NBR_TABLE_REASON_IPV6_ND_AUTOFILL: return find_worst_rank_nbr_lladdr(); default: return NULL; } } /*---------------------------------------------------------------------------*/ /** @}*/