581 lines
16 KiB
C
581 lines
16 KiB
C
/**
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* @file
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*
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* Multicast listener discovery for IPv6. Aims to be compliant with RFC 2710.
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* No support for MLDv2.
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*/
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/*
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* Copyright (c) 2010 Inico Technologies Ltd.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* This file is part of the lwIP TCP/IP stack.
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*
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* Author: Ivan Delamer <delamer@inicotech.com>
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*
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*
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* Please coordinate changes and requests with Ivan Delamer
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* <delamer@inicotech.com>
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*/
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/* Based on igmp.c implementation of igmp v2 protocol */
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#include "lwip/opt.h"
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#if LWIP_IPV6 && LWIP_IPV6_MLD /* don't build if not configured for use in lwipopts.h */
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#include "lwip/mld6.h"
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#include "lwip/icmp6.h"
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#include "lwip/ip6.h"
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#include "lwip/ip6_addr.h"
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#include "lwip/inet_chksum.h"
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#include "lwip/pbuf.h"
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#include "lwip/netif.h"
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#include "lwip/memp.h"
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#include "lwip/stats.h"
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#include <string.h>
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/*
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* MLD constants
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*/
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#define MLD6_HL 1
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#define MLD6_JOIN_DELAYING_MEMBER_TMR_MS (500)
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#define MLD6_GROUP_NON_MEMBER 0
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#define MLD6_GROUP_DELAYING_MEMBER 1
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#define MLD6_GROUP_IDLE_MEMBER 2
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/* The list of joined groups. */
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static struct mld_group* mld_group_list;
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/* Forward declarations. */
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static struct mld_group * mld6_new_group(struct netif *ifp, ip6_addr_t *addr);
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static err_t mld6_free_group(struct mld_group *group);
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static void mld6_delayed_report(struct mld_group *group, u16_t maxresp);
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static void mld6_send(struct mld_group *group, u8_t type);
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/**
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* Stop MLD processing on interface
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*
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* @param netif network interface on which stop MLD processing
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*/
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err_t
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mld6_stop(struct netif *netif)
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{
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struct mld_group *group = mld_group_list;
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struct mld_group *prev = NULL;
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struct mld_group *next;
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/* look for groups joined on this interface further down the list */
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while (group != NULL) {
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next = group->next;
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/* is it a group joined on this interface? */
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if (group->netif == netif) {
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/* is it the first group of the list? */
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if (group == mld_group_list) {
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mld_group_list = next;
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}
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/* is there a "previous" group defined? */
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if (prev != NULL) {
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prev->next = next;
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}
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/* disable the group at the MAC level */
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if (netif->mld_mac_filter != NULL) {
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netif->mld_mac_filter(netif, &(group->group_address), MLD6_DEL_MAC_FILTER);
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}
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/* free group */
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memp_free(MEMP_MLD6_GROUP, group);
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} else {
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/* change the "previous" */
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prev = group;
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}
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/* move to "next" */
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group = next;
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}
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return ERR_OK;
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}
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/**
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* Report MLD memberships for this interface
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*
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* @param netif network interface on which report MLD memberships
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*/
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void
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mld6_report_groups(struct netif *netif)
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{
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struct mld_group *group = mld_group_list;
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while (group != NULL) {
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if (group->netif == netif) {
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mld6_delayed_report(group, MLD6_JOIN_DELAYING_MEMBER_TMR_MS);
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}
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group = group->next;
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}
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}
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/**
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* Search for a group that is joined on a netif
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*
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* @param ifp the network interface for which to look
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* @param addr the group ipv6 address to search for
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* @return a struct mld_group* if the group has been found,
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* NULL if the group wasn't found.
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*/
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struct mld_group *
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mld6_lookfor_group(struct netif *ifp, ip6_addr_t *addr)
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{
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struct mld_group *group = mld_group_list;
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while (group != NULL) {
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if ((group->netif == ifp) && (ip6_addr_cmp(&(group->group_address), addr))) {
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return group;
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}
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group = group->next;
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}
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return NULL;
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}
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/**
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* create a new group
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*
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* @param ifp the network interface for which to create
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* @param addr the new group ipv6
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* @return a struct mld_group*,
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* NULL on memory error.
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*/
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static struct mld_group *
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mld6_new_group(struct netif *ifp, ip6_addr_t *addr)
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{
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struct mld_group *group;
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group = (struct mld_group *)memp_malloc(MEMP_MLD6_GROUP);
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if (group != NULL) {
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group->netif = ifp;
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ip6_addr_set(&(group->group_address), addr);
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group->timer = 0; /* Not running */
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group->group_state = MLD6_GROUP_IDLE_MEMBER;
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group->last_reporter_flag = 0;
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group->use = 0;
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group->next = mld_group_list;
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mld_group_list = group;
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}
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return group;
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}
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/**
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* Remove a group in the mld_group_list and free
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*
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* @param group the group to remove
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* @return ERR_OK if group was removed from the list, an err_t otherwise
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*/
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static err_t
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mld6_free_group(struct mld_group *group)
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{
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err_t err = ERR_OK;
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/* Is it the first group? */
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if (mld_group_list == group) {
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mld_group_list = group->next;
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} else {
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/* look for group further down the list */
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struct mld_group *tmpGroup;
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for (tmpGroup = mld_group_list; tmpGroup != NULL; tmpGroup = tmpGroup->next) {
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if (tmpGroup->next == group) {
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tmpGroup->next = group->next;
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break;
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}
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}
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/* Group not find group */
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if (tmpGroup == NULL)
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err = ERR_ARG;
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}
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/* free group */
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memp_free(MEMP_MLD6_GROUP, group);
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return err;
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}
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/**
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* Process an input MLD message. Called by icmp6_input.
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*
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* @param p the mld packet, p->payload pointing to the icmpv6 header
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* @param inp the netif on which this packet was received
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*/
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void
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mld6_input(struct pbuf *p, struct netif *inp)
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{
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struct mld_header * mld_hdr;
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struct mld_group* group;
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MLD6_STATS_INC(mld6.recv);
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/* Check that mld header fits in packet. */
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if (p->len < sizeof(struct mld_header)) {
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/* TODO debug message */
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pbuf_free(p);
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MLD6_STATS_INC(mld6.lenerr);
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MLD6_STATS_INC(mld6.drop);
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return;
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}
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mld_hdr = (struct mld_header *)p->payload;
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switch (mld_hdr->type) {
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case ICMP6_TYPE_MLQ: /* Multicast listener query. */
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{
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/* Is it a general query? */
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if (ip6_addr_isallnodes_linklocal(ip6_current_dest_addr()) &&
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ip6_addr_isany(&(mld_hdr->multicast_address))) {
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MLD6_STATS_INC(mld6.rx_general);
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/* Report all groups, except all nodes group, and if-local groups. */
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group = mld_group_list;
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while (group != NULL) {
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if ((group->netif == inp) &&
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(!(ip6_addr_ismulticast_iflocal(&(group->group_address)))) &&
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(!(ip6_addr_isallnodes_linklocal(&(group->group_address))))) {
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mld6_delayed_report(group, mld_hdr->max_resp_delay);
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}
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group = group->next;
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}
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}
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else {
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/* Have we joined this group?
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* We use IP6 destination address to have a memory aligned copy.
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* mld_hdr->multicast_address should be the same. */
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MLD6_STATS_INC(mld6.rx_group);
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group = mld6_lookfor_group(inp, ip6_current_dest_addr());
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if (group != NULL) {
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/* Schedule a report. */
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mld6_delayed_report(group, mld_hdr->max_resp_delay);
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}
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}
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break; /* ICMP6_TYPE_MLQ */
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}
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case ICMP6_TYPE_MLR: /* Multicast listener report. */
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{
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/* Have we joined this group?
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* We use IP6 destination address to have a memory aligned copy.
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* mld_hdr->multicast_address should be the same. */
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MLD6_STATS_INC(mld6.rx_report);
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group = mld6_lookfor_group(inp, ip6_current_dest_addr());
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if (group != NULL) {
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/* If we are waiting to report, cancel it. */
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if (group->group_state == MLD6_GROUP_DELAYING_MEMBER) {
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group->timer = 0; /* stopped */
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group->group_state = MLD6_GROUP_IDLE_MEMBER;
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group->last_reporter_flag = 0;
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}
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}
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break; /* ICMP6_TYPE_MLR */
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}
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case ICMP6_TYPE_MLD: /* Multicast listener done. */
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{
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/* Do nothing, router will query us. */
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break; /* ICMP6_TYPE_MLD */
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}
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default:
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MLD6_STATS_INC(mld6.proterr);
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MLD6_STATS_INC(mld6.drop);
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break;
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}
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pbuf_free(p);
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}
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/**
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* Join a group on a network interface.
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*
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* @param srcaddr ipv6 address of the network interface which should
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* join a new group. If IP6_ADDR_ANY, join on all netifs
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* @param groupaddr the ipv6 address of the group to join
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* @return ERR_OK if group was joined on the netif(s), an err_t otherwise
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*/
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err_t
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mld6_joingroup(ip6_addr_t *srcaddr, ip6_addr_t *groupaddr)
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{
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err_t err = ERR_VAL; /* no matching interface */
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struct mld_group *group;
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struct netif *netif;
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u8_t match;
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u8_t i;
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/* loop through netif's */
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netif = netif_list;
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while (netif != NULL) {
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/* Should we join this interface ? */
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match = 0;
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if (ip6_addr_isany(srcaddr)) {
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match = 1;
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}
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else {
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for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
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if (ip6_addr_cmp(srcaddr, netif_ip6_addr(netif, i))) {
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match = 1;
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break;
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}
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}
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}
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if (match) {
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/* find group or create a new one if not found */
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group = mld6_lookfor_group(netif, groupaddr);
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if (group == NULL) {
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/* Joining a new group. Create a new group entry. */
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group = mld6_new_group(netif, groupaddr);
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if (group == NULL) {
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return ERR_MEM;
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}
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/* Activate this address on the MAC layer. */
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if (netif->mld_mac_filter != NULL) {
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netif->mld_mac_filter(netif, groupaddr, MLD6_ADD_MAC_FILTER);
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}
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/* Report our membership. */
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MLD6_STATS_INC(mld6.tx_report);
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mld6_send(group, ICMP6_TYPE_MLR);
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mld6_delayed_report(group, MLD6_JOIN_DELAYING_MEMBER_TMR_MS);
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}
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/* Increment group use */
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group->use++;
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err = ERR_OK;
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}
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/* proceed to next network interface */
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netif = netif->next;
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}
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return err;
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}
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/**
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* Leave a group on a network interface.
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*
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* @param srcaddr ipv6 address of the network interface which should
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* leave the group. If IP6_ISANY, leave on all netifs
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* @param groupaddr the ipv6 address of the group to leave
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* @return ERR_OK if group was left on the netif(s), an err_t otherwise
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*/
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err_t
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mld6_leavegroup(ip6_addr_t *srcaddr, ip6_addr_t *groupaddr)
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{
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err_t err = ERR_VAL; /* no matching interface */
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struct mld_group *group;
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struct netif *netif;
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u8_t match;
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u8_t i;
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/* loop through netif's */
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netif = netif_list;
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while (netif != NULL) {
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/* Should we leave this interface ? */
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match = 0;
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if (ip6_addr_isany(srcaddr)) {
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match = 1;
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}
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else {
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for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
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if (ip6_addr_cmp(srcaddr, netif_ip6_addr(netif, i))) {
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match = 1;
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break;
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}
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}
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}
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if (match) {
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/* find group */
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group = mld6_lookfor_group(netif, groupaddr);
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if (group != NULL) {
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/* Leave if there is no other use of the group */
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if (group->use <= 1) {
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/* If we are the last reporter for this group */
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if (group->last_reporter_flag) {
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MLD6_STATS_INC(mld6.tx_leave);
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mld6_send(group, ICMP6_TYPE_MLD);
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}
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/* Disable the group at the MAC level */
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if (netif->mld_mac_filter != NULL) {
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netif->mld_mac_filter(netif, groupaddr, MLD6_DEL_MAC_FILTER);
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}
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/* Free the group */
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mld6_free_group(group);
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} else {
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/* Decrement group use */
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group->use--;
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}
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/* Leave on this interface */
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err = ERR_OK;
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}
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}
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/* proceed to next network interface */
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netif = netif->next;
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}
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return err;
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}
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/**
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* Periodic timer for mld processing. Must be called every
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* MLD6_TMR_INTERVAL milliseconds (100).
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*
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* When a delaying member expires, a membership report is sent.
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*/
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void
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mld6_tmr(void)
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{
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struct mld_group *group = mld_group_list;
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while (group != NULL) {
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if (group->timer > 0) {
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group->timer--;
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if (group->timer == 0) {
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/* If the state is MLD6_GROUP_DELAYING_MEMBER then we send a report for this group */
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if (group->group_state == MLD6_GROUP_DELAYING_MEMBER) {
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MLD6_STATS_INC(mld6.tx_report);
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mld6_send(group, ICMP6_TYPE_MLR);
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group->group_state = MLD6_GROUP_IDLE_MEMBER;
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}
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}
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}
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group = group->next;
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}
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}
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/**
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* Schedule a delayed membership report for a group
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*
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* @param group the mld_group for which "delaying" membership report
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* should be sent
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* @param maxresp the max resp delay provided in the query
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*/
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static void
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mld6_delayed_report(struct mld_group *group, u16_t maxresp)
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{
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/* Convert maxresp from milliseconds to tmr ticks */
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maxresp = maxresp / MLD6_TMR_INTERVAL;
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if (maxresp == 0) {
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maxresp = 1;
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}
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#ifdef LWIP_RAND
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/* Randomize maxresp. (if LWIP_RAND is supported) */
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maxresp = (LWIP_RAND() % (maxresp - 1)) + 1;
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#endif /* LWIP_RAND */
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/* Apply timer value if no report has been scheduled already. */
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if ((group->group_state == MLD6_GROUP_IDLE_MEMBER) ||
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((group->group_state == MLD6_GROUP_DELAYING_MEMBER) &&
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((group->timer == 0) || (maxresp < group->timer)))) {
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group->timer = maxresp;
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group->group_state = MLD6_GROUP_DELAYING_MEMBER;
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}
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}
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/**
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* Send a MLD message (report or done).
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|
*
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|
* An IPv6 hop-by-hop options header with a router alert option
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* is prepended.
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*
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* @param group the group to report or quit
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|
* @param type ICMP6_TYPE_MLR (report) or ICMP6_TYPE_MLD (done)
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*/
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static void
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mld6_send(struct mld_group *group, u8_t type)
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{
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struct mld_header * mld_hdr;
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struct pbuf * p;
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ip6_addr_t * src_addr;
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/* Allocate a packet. Size is MLD header + IPv6 Hop-by-hop options header. */
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p = pbuf_alloc(PBUF_IP, sizeof(struct mld_header) + sizeof(struct ip6_hbh_hdr), PBUF_RAM);
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if ((p == NULL) || (p->len < (sizeof(struct mld_header) + sizeof(struct ip6_hbh_hdr)))) {
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/* We couldn't allocate a suitable pbuf. drop it. */
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if (p != NULL) {
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pbuf_free(p);
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}
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MLD6_STATS_INC(mld6.memerr);
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return;
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}
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/* Move to make room for Hop-by-hop options header. */
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if (pbuf_header(p, -IP6_HBH_HLEN)) {
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pbuf_free(p);
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MLD6_STATS_INC(mld6.lenerr);
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return;
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}
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/* Select our source address. */
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if (!ip6_addr_isvalid(netif_ip6_addr_state(group->netif, 0))) {
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/* This is a special case, when we are performing duplicate address detection.
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* We must join the multicast group, but we don't have a valid address yet. */
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src_addr = IP6_ADDR_ANY;
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} else {
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/* Use link-local address as source address. */
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src_addr = netif_ip6_addr(group->netif, 0);
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}
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/* MLD message header pointer. */
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mld_hdr = (struct mld_header *)p->payload;
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/* Set fields. */
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mld_hdr->type = type;
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mld_hdr->code = 0;
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mld_hdr->chksum = 0;
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mld_hdr->max_resp_delay = 0;
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mld_hdr->reserved = 0;
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ip6_addr_set(&(mld_hdr->multicast_address), &(group->group_address));
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mld_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len,
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src_addr, &(group->group_address));
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/* Add hop-by-hop headers options: router alert with MLD value. */
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ip6_options_add_hbh_ra(p, IP6_NEXTH_ICMP6, IP6_ROUTER_ALERT_VALUE_MLD);
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/* Send the packet out. */
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MLD6_STATS_INC(mld6.xmit);
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ip6_output_if(p, (ip6_addr_isany(src_addr)) ? NULL : src_addr, &(group->group_address),
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MLD6_HL, 0, IP6_NEXTH_HOPBYHOP, group->netif);
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pbuf_free(p);
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}
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#endif /* LWIP_IPV6 */
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