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/**
* @file
* Multicast listener discovery
*
* @defgroup mld6 MLD6
* @ingroup ip6
* Multicast listener discovery for IPv6. Aims to be compliant with RFC 2710.
* No support for MLDv2.\n
* To be called from TCPIP thread
*/
/*
* Copyright (c) 2010 Inico Technologies Ltd.
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Ivan Delamer <delamer@inicotech.com>
*
*
* Please coordinate changes and requests with Ivan Delamer
* <delamer@inicotech.com>
*/
/* Based on igmp.c implementation of igmp v2 protocol */
#include "lwip/opt.h"
#if LWIP_IPV6 && LWIP_IPV6_MLD /* don't build if not configured for use in lwipopts.h */
#include "lwip/mld6.h"
#include "lwip/prot/mld6.h"
#include "lwip/icmp6.h"
#include "lwip/ip6.h"
#include "lwip/ip6_addr.h"
#include "lwip/ip.h"
#include "lwip/inet_chksum.h"
#include "lwip/pbuf.h"
#include "lwip/netif.h"
#include "lwip/memp.h"
#include "lwip/stats.h"
#include <string.h>
/*
* MLD constants
*/
#define MLD6_HL 1
#define MLD6_JOIN_DELAYING_MEMBER_TMR_MS (500)
#define MLD6_GROUP_NON_MEMBER 0
#define MLD6_GROUP_DELAYING_MEMBER 1
#define MLD6_GROUP_IDLE_MEMBER 2
/* Forward declarations. */
static struct mld_group *mld6_new_group(struct netif *ifp, const ip6_addr_t *addr);
static err_t mld6_remove_group(struct netif *netif, struct mld_group *group);
static void mld6_delayed_report(struct mld_group *group, u16_t maxresp);
static void mld6_send(struct netif *netif, struct mld_group *group, u8_t type);
/**
* Stop MLD processing on interface
*
* @param netif network interface on which stop MLD processing
*/
err_t
mld6_stop(struct netif *netif)
{
struct mld_group *group = netif_mld6_data(netif);
netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, NULL);
while (group != NULL) {
struct mld_group *next = group->next; /* avoid use-after-free below */
/* disable the group at the MAC level */
if (netif->mld_mac_filter != NULL) {
netif->mld_mac_filter(netif, &(group->group_address), NETIF_DEL_MAC_FILTER);
}
/* free group */
memp_free(MEMP_MLD6_GROUP, group);
/* move to "next" */
group = next;
}
return ERR_OK;
}
/**
* Report MLD memberships for this interface
*
* @param netif network interface on which report MLD memberships
*/
void
mld6_report_groups(struct netif *netif)
{
struct mld_group *group = netif_mld6_data(netif);
while (group != NULL) {
mld6_delayed_report(group, MLD6_JOIN_DELAYING_MEMBER_TMR_MS);
group = group->next;
}
}
/**
* Search for a group that is joined on a netif
*
* @param ifp the network interface for which to look
* @param addr the group ipv6 address to search for
* @return a struct mld_group* if the group has been found,
* NULL if the group wasn't found.
*/
struct mld_group *
mld6_lookfor_group(struct netif *ifp, const ip6_addr_t *addr)
{
struct mld_group *group = netif_mld6_data(ifp);
while (group != NULL) {
if (ip6_addr_cmp(&(group->group_address), addr)) {
return group;
}
group = group->next;
}
return NULL;
}
/**
* create a new group
*
* @param ifp the network interface for which to create
* @param addr the new group ipv6
* @return a struct mld_group*,
* NULL on memory error.
*/
static struct mld_group *
mld6_new_group(struct netif *ifp, const ip6_addr_t *addr)
{
struct mld_group *group;
group = (struct mld_group *)memp_malloc(MEMP_MLD6_GROUP);
if (group != NULL) {
ip6_addr_set(&(group->group_address), addr);
group->timer = 0; /* Not running */
group->group_state = MLD6_GROUP_IDLE_MEMBER;
group->last_reporter_flag = 0;
group->use = 0;
group->next = netif_mld6_data(ifp);
netif_set_client_data(ifp, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, group);
}
return group;
}
/**
* Remove a group from the mld_group_list, but do not free it yet
*
* @param group the group to remove
* @return ERR_OK if group was removed from the list, an err_t otherwise
*/
static err_t
mld6_remove_group(struct netif *netif, struct mld_group *group)
{
err_t err = ERR_OK;
/* Is it the first group? */
if (netif_mld6_data(netif) == group) {
netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, group->next);
} else {
/* look for group further down the list */
struct mld_group *tmpGroup;
for (tmpGroup = netif_mld6_data(netif); tmpGroup != NULL; tmpGroup = tmpGroup->next) {
if (tmpGroup->next == group) {
tmpGroup->next = group->next;
break;
}
}
/* Group not find group */
if (tmpGroup == NULL) {
err = ERR_ARG;
}
}
return err;
}
/**
* Process an input MLD message. Called by icmp6_input.
*
* @param p the mld packet, p->payload pointing to the icmpv6 header
* @param inp the netif on which this packet was received
*/
void
mld6_input(struct pbuf *p, struct netif *inp)
{
struct mld_header *mld_hdr;
struct mld_group *group;
MLD6_STATS_INC(mld6.recv);
/* Check that mld header fits in packet. */
if (p->len < sizeof(struct mld_header)) {
/* @todo debug message */
pbuf_free(p);
MLD6_STATS_INC(mld6.lenerr);
MLD6_STATS_INC(mld6.drop);
return;
}
mld_hdr = (struct mld_header *)p->payload;
switch (mld_hdr->type) {
case ICMP6_TYPE_MLQ: /* Multicast listener query. */
/* Is it a general query? */
if (ip6_addr_isallnodes_linklocal(ip6_current_dest_addr()) &&
ip6_addr_isany(&(mld_hdr->multicast_address))) {
MLD6_STATS_INC(mld6.rx_general);
/* Report all groups, except all nodes group, and if-local groups. */
group = netif_mld6_data(inp);
while (group != NULL) {
if ((!(ip6_addr_ismulticast_iflocal(&(group->group_address)))) &&
(!(ip6_addr_isallnodes_linklocal(&(group->group_address))))) {
mld6_delayed_report(group, mld_hdr->max_resp_delay);
}
group = group->next;
}
} else {
/* Have we joined this group?
* We use IP6 destination address to have a memory aligned copy.
* mld_hdr->multicast_address should be the same. */
MLD6_STATS_INC(mld6.rx_group);
group = mld6_lookfor_group(inp, ip6_current_dest_addr());
if (group != NULL) {
/* Schedule a report. */
mld6_delayed_report(group, mld_hdr->max_resp_delay);
}
}
break; /* ICMP6_TYPE_MLQ */
case ICMP6_TYPE_MLR: /* Multicast listener report. */
/* Have we joined this group?
* We use IP6 destination address to have a memory aligned copy.
* mld_hdr->multicast_address should be the same. */
MLD6_STATS_INC(mld6.rx_report);
group = mld6_lookfor_group(inp, ip6_current_dest_addr());
if (group != NULL) {
/* If we are waiting to report, cancel it. */
if (group->group_state == MLD6_GROUP_DELAYING_MEMBER) {
group->timer = 0; /* stopped */
group->group_state = MLD6_GROUP_IDLE_MEMBER;
group->last_reporter_flag = 0;
}
}
break; /* ICMP6_TYPE_MLR */
case ICMP6_TYPE_MLD: /* Multicast listener done. */
/* Do nothing, router will query us. */
break; /* ICMP6_TYPE_MLD */
default:
MLD6_STATS_INC(mld6.proterr);
MLD6_STATS_INC(mld6.drop);
break;
}
pbuf_free(p);
}
/**
* @ingroup mld6
* Join a group on one or all network interfaces.
*
* If the group is to be joined on all interfaces, the given group address must
* not have a zone set (i.e., it must have its zone index set to IP6_NO_ZONE).
* If the group is to be joined on one particular interface, the given group
* address may or may not have a zone set.
*
* @param srcaddr ipv6 address (zoned) of the network interface which should
* join a new group. If IP6_ADDR_ANY6, join on all netifs
* @param groupaddr the ipv6 address of the group to join (possibly but not
* necessarily zoned)
* @return ERR_OK if group was joined on the netif(s), an err_t otherwise
*/
err_t
mld6_joingroup(const ip6_addr_t *srcaddr, const ip6_addr_t *groupaddr)
{
err_t err = ERR_VAL; /* no matching interface */
struct netif *netif;
/* loop through netif's */
NETIF_FOREACH(netif) {
/* Should we join this interface ? */
if (ip6_addr_isany(srcaddr) ||
netif_get_ip6_addr_match(netif, srcaddr) >= 0) {
err = mld6_joingroup_netif(netif, groupaddr);
if (err != ERR_OK) {
return err;
}
}
}
return err;
}
/**
* @ingroup mld6
* Join a group on a network interface.
*
* @param netif the network interface which should join a new group.
* @param groupaddr the ipv6 address of the group to join (possibly but not
* necessarily zoned)
* @return ERR_OK if group was joined on the netif, an err_t otherwise
*/
err_t
mld6_joingroup_netif(struct netif *netif, const ip6_addr_t *groupaddr)
{
struct mld_group *group;
#if LWIP_IPV6_SCOPES
ip6_addr_t ip6addr;
/* If the address has a particular scope but no zone set, use the netif to
* set one now. Within the mld6 module, all addresses are properly zoned. */
if (ip6_addr_lacks_zone(groupaddr, IP6_MULTICAST)) {
ip6_addr_set(&ip6addr, groupaddr);
ip6_addr_assign_zone(&ip6addr, IP6_MULTICAST, netif);
groupaddr = &ip6addr;
}
IP6_ADDR_ZONECHECK_NETIF(groupaddr, netif);
#endif /* LWIP_IPV6_SCOPES */
/* find group or create a new one if not found */
group = mld6_lookfor_group(netif, groupaddr);
if (group == NULL) {
/* Joining a new group. Create a new group entry. */
group = mld6_new_group(netif, groupaddr);
if (group == NULL) {
return ERR_MEM;
}
/* Activate this address on the MAC layer. */
if (netif->mld_mac_filter != NULL) {
netif->mld_mac_filter(netif, groupaddr, NETIF_ADD_MAC_FILTER);
}
/* Report our membership. */
MLD6_STATS_INC(mld6.tx_report);
mld6_send(netif, group, ICMP6_TYPE_MLR);
mld6_delayed_report(group, MLD6_JOIN_DELAYING_MEMBER_TMR_MS);
}
/* Increment group use */
group->use++;
return ERR_OK;
}
/**
* @ingroup mld6
* Leave a group on a network interface.
*
* Zoning of address follows the same rules as @ref mld6_joingroup.
*
* @param srcaddr ipv6 address (zoned) of the network interface which should
* leave the group. If IP6_ADDR_ANY6, leave on all netifs
* @param groupaddr the ipv6 address of the group to leave (possibly, but not
* necessarily zoned)
* @return ERR_OK if group was left on the netif(s), an err_t otherwise
*/
err_t
mld6_leavegroup(const ip6_addr_t *srcaddr, const ip6_addr_t *groupaddr)
{
err_t err = ERR_VAL; /* no matching interface */
struct netif *netif;
/* loop through netif's */
NETIF_FOREACH(netif) {
/* Should we leave this interface ? */
if (ip6_addr_isany(srcaddr) ||
netif_get_ip6_addr_match(netif, srcaddr) >= 0) {
err_t res = mld6_leavegroup_netif(netif, groupaddr);
if (err != ERR_OK) {
/* Store this result if we have not yet gotten a success */
err = res;
}
}
}
return err;
}
/**
* @ingroup mld6
* Leave a group on a network interface.
*
* @param netif the network interface which should leave the group.
* @param groupaddr the ipv6 address of the group to leave (possibly, but not
* necessarily zoned)
* @return ERR_OK if group was left on the netif, an err_t otherwise
*/
err_t
mld6_leavegroup_netif(struct netif *netif, const ip6_addr_t *groupaddr)
{
struct mld_group *group;
#if LWIP_IPV6_SCOPES
ip6_addr_t ip6addr;
if (ip6_addr_lacks_zone(groupaddr, IP6_MULTICAST)) {
ip6_addr_set(&ip6addr, groupaddr);
ip6_addr_assign_zone(&ip6addr, IP6_MULTICAST, netif);
groupaddr = &ip6addr;
}
IP6_ADDR_ZONECHECK_NETIF(groupaddr, netif);
#endif /* LWIP_IPV6_SCOPES */
/* find group */
group = mld6_lookfor_group(netif, groupaddr);
if (group != NULL) {
/* Leave if there is no other use of the group */
if (group->use <= 1) {
/* Remove the group from the list */
mld6_remove_group(netif, group);
/* If we are the last reporter for this group */
if (group->last_reporter_flag) {
MLD6_STATS_INC(mld6.tx_leave);
mld6_send(netif, group, ICMP6_TYPE_MLD);
}
/* Disable the group at the MAC level */
if (netif->mld_mac_filter != NULL) {
netif->mld_mac_filter(netif, groupaddr, NETIF_DEL_MAC_FILTER);
}
/* free group struct */
memp_free(MEMP_MLD6_GROUP, group);
} else {
/* Decrement group use */
group->use--;
}
/* Left group */
return ERR_OK;
}
/* Group not found */
return ERR_VAL;
}
/**
* Periodic timer for mld processing. Must be called every
* MLD6_TMR_INTERVAL milliseconds (100).
*
* When a delaying member expires, a membership report is sent.
*/
void
mld6_tmr(void)
{
struct netif *netif;
NETIF_FOREACH(netif) {
struct mld_group *group = netif_mld6_data(netif);
while (group != NULL) {
if (group->timer > 0) {
group->timer--;
if (group->timer == 0) {
/* If the state is MLD6_GROUP_DELAYING_MEMBER then we send a report for this group */
if (group->group_state == MLD6_GROUP_DELAYING_MEMBER) {
MLD6_STATS_INC(mld6.tx_report);
mld6_send(netif, group, ICMP6_TYPE_MLR);
group->group_state = MLD6_GROUP_IDLE_MEMBER;
}
}
}
group = group->next;
}
}
}
/**
* Schedule a delayed membership report for a group
*
* @param group the mld_group for which "delaying" membership report
* should be sent
* @param maxresp_in the max resp delay provided in the query
*/
static void
mld6_delayed_report(struct mld_group *group, u16_t maxresp_in)
{
/* Convert maxresp from milliseconds to tmr ticks */
u16_t maxresp = maxresp_in / MLD6_TMR_INTERVAL;
if (maxresp == 0) {
maxresp = 1;
}
#ifdef LWIP_RAND
/* Randomize maxresp. (if LWIP_RAND is supported) */
maxresp = (u16_t)(LWIP_RAND() % maxresp);
if (maxresp == 0) {
maxresp = 1;
}
#endif /* LWIP_RAND */
/* Apply timer value if no report has been scheduled already. */
if ((group->group_state == MLD6_GROUP_IDLE_MEMBER) ||
((group->group_state == MLD6_GROUP_DELAYING_MEMBER) &&
((group->timer == 0) || (maxresp < group->timer)))) {
group->timer = maxresp;
group->group_state = MLD6_GROUP_DELAYING_MEMBER;
}
}
/**
* Send a MLD message (report or done).
*
* An IPv6 hop-by-hop options header with a router alert option
* is prepended.
*
* @param group the group to report or quit
* @param type ICMP6_TYPE_MLR (report) or ICMP6_TYPE_MLD (done)
*/
static void
mld6_send(struct netif *netif, struct mld_group *group, u8_t type)
{
struct mld_header *mld_hdr;
struct pbuf *p;
const ip6_addr_t *src_addr;
/* Allocate a packet. Size is MLD header + IPv6 Hop-by-hop options header. */
p = pbuf_alloc(PBUF_IP, sizeof(struct mld_header) + MLD6_HBH_HLEN, PBUF_RAM);
if (p == NULL) {
MLD6_STATS_INC(mld6.memerr);
return;
}
/* Move to make room for Hop-by-hop options header. */
if (pbuf_remove_header(p, MLD6_HBH_HLEN)) {
pbuf_free(p);
MLD6_STATS_INC(mld6.lenerr);
return;
}
/* Select our source address. */
if (!ip6_addr_isvalid(netif_ip6_addr_state(netif, 0))) {
/* This is a special case, when we are performing duplicate address detection.
* We must join the multicast group, but we don't have a valid address yet. */
src_addr = IP6_ADDR_ANY6;
} else {
/* Use link-local address as source address. */
src_addr = netif_ip6_addr(netif, 0);
}
/* MLD message header pointer. */
mld_hdr = (struct mld_header *)p->payload;
/* Set fields. */
mld_hdr->type = type;
mld_hdr->code = 0;
mld_hdr->chksum = 0;
mld_hdr->max_resp_delay = 0;
mld_hdr->reserved = 0;
ip6_addr_copy_to_packed(mld_hdr->multicast_address, group->group_address);
#if CHECKSUM_GEN_ICMP6
IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
mld_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len,
src_addr, &(group->group_address));
}
#endif /* CHECKSUM_GEN_ICMP6 */
/* Add hop-by-hop headers options: router alert with MLD value. */
ip6_options_add_hbh_ra(p, IP6_NEXTH_ICMP6, IP6_ROUTER_ALERT_VALUE_MLD);
if (type == ICMP6_TYPE_MLR) {
/* Remember we were the last to report */
group->last_reporter_flag = 1;
}
/* Send the packet out. */
MLD6_STATS_INC(mld6.xmit);
ip6_output_if(p, (ip6_addr_isany(src_addr)) ? NULL : src_addr, &(group->group_address),
MLD6_HL, 0, IP6_NEXTH_HOPBYHOP, netif);
pbuf_free(p);
}
#endif /* LWIP_IPV6 */