BadVPN – Rev 1
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/**
* @file
* IGMP - Internet Group Management Protocol
*
* @defgroup igmp IGMP
* @ingroup ip4
* To be called from TCPIP thread
*/
/*
* Copyright (c) 2002 CITEL 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. Neither the name of CITEL Technologies Ltd 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 CITEL TECHNOLOGIES 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 CITEL TECHNOLOGIES OR CONTRIBUTORS 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 a contribution to the lwIP TCP/IP stack.
* The Swedish Institute of Computer Science and Adam Dunkels
* are specifically granted permission to redistribute this
* source code.
*/
/*-------------------------------------------------------------
Note 1)
Although the rfc requires V1 AND V2 capability
we will only support v2 since now V1 is very old (August 1989)
V1 can be added if required
a debug print and statistic have been implemented to
show this up.
-------------------------------------------------------------
-------------------------------------------------------------
Note 2)
A query for a specific group address (as opposed to ALLHOSTS)
has now been implemented as I am unsure if it is required
a debug print and statistic have been implemented to
show this up.
-------------------------------------------------------------
-------------------------------------------------------------
Note 3)
The router alert rfc 2113 is implemented in outgoing packets
but not checked rigorously incoming
-------------------------------------------------------------
Steve Reynolds
------------------------------------------------------------*/
/*-----------------------------------------------------------------------------
* RFC 988 - Host extensions for IP multicasting - V0
* RFC 1054 - Host extensions for IP multicasting -
* RFC 1112 - Host extensions for IP multicasting - V1
* RFC 2236 - Internet Group Management Protocol, Version 2 - V2 <- this code is based on this RFC (it's the "de facto" standard)
* RFC 3376 - Internet Group Management Protocol, Version 3 - V3
* RFC 4604 - Using Internet Group Management Protocol Version 3... - V3+
* RFC 2113 - IP Router Alert Option -
*----------------------------------------------------------------------------*/
/*-----------------------------------------------------------------------------
* Includes
*----------------------------------------------------------------------------*/
#include "lwip/opt.h"
#if LWIP_IPV4 && LWIP_IGMP /* don't build if not configured for use in lwipopts.h */
#include "lwip/igmp.h"
#include "lwip/debug.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/ip.h"
#include "lwip/inet_chksum.h"
#include "lwip/netif.h"
#include "lwip/stats.h"
#include "lwip/prot/igmp.h"
#include "string.h"
static struct igmp_group *igmp_lookup_group(struct netif *ifp, const ip4_addr_t *addr);
static err_t igmp_remove_group(struct netif *netif, struct igmp_group *group);
static void igmp_timeout(struct netif *netif, struct igmp_group *group);
static void igmp_start_timer(struct igmp_group *group, u8_t max_time);
static void igmp_delaying_member(struct igmp_group *group, u8_t maxresp);
static err_t igmp_ip_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest, struct netif *netif);
static void igmp_send(struct netif *netif, struct igmp_group *group, u8_t type);
static ip4_addr_t allsystems;
static ip4_addr_t allrouters;
/**
* Initialize the IGMP module
*/
void
igmp_init(void)
{
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_init: initializing\n"));
IP4_ADDR(&allsystems, 224, 0, 0, 1);
IP4_ADDR(&allrouters, 224, 0, 0, 2);
}
/**
* Start IGMP processing on interface
*
* @param netif network interface on which start IGMP processing
*/
err_t
igmp_start(struct netif *netif)
{
struct igmp_group *group;
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_start: starting IGMP processing on if %p\n", (void *)netif));
group = igmp_lookup_group(netif, &allsystems);
if (group != NULL) {
group->group_state = IGMP_GROUP_IDLE_MEMBER;
group->use++;
/* Allow the igmp messages at the MAC level */
if (netif->igmp_mac_filter != NULL) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_start: igmp_mac_filter(ADD "));
ip4_addr_debug_print_val(IGMP_DEBUG, allsystems);
LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", (void *)netif));
netif->igmp_mac_filter(netif, &allsystems, NETIF_ADD_MAC_FILTER);
}
return ERR_OK;
}
return ERR_MEM;
}
/**
* Stop IGMP processing on interface
*
* @param netif network interface on which stop IGMP processing
*/
err_t
igmp_stop(struct netif *netif)
{
struct igmp_group *group = netif_igmp_data(netif);
netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_IGMP, NULL);
while (group != NULL) {
struct igmp_group *next = group->next; /* avoid use-after-free below */
/* disable the group at the MAC level */
if (netif->igmp_mac_filter != NULL) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_stop: igmp_mac_filter(DEL "));
ip4_addr_debug_print(IGMP_DEBUG, &group->group_address);
LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", (void *)netif));
netif->igmp_mac_filter(netif, &(group->group_address), NETIF_DEL_MAC_FILTER);
}
/* free group */
memp_free(MEMP_IGMP_GROUP, group);
/* move to "next" */
group = next;
}
return ERR_OK;
}
/**
* Report IGMP memberships for this interface
*
* @param netif network interface on which report IGMP memberships
*/
void
igmp_report_groups(struct netif *netif)
{
struct igmp_group *group = netif_igmp_data(netif);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_report_groups: sending IGMP reports on if %p\n", (void *)netif));
/* Skip the first group in the list, it is always the allsystems group added in igmp_start() */
if (group != NULL) {
group = group->next;
}
while (group != NULL) {
igmp_delaying_member(group, IGMP_JOIN_DELAYING_MEMBER_TMR);
group = group->next;
}
}
/**
* Search for a group in the netif's igmp group list
*
* @param ifp the network interface for which to look
* @param addr the group ip address to search for
* @return a struct igmp_group* if the group has been found,
* NULL if the group wasn't found.
*/
struct igmp_group *
igmp_lookfor_group(struct netif *ifp, const ip4_addr_t *addr)
{
struct igmp_group *group = netif_igmp_data(ifp);
while (group != NULL) {
if (ip4_addr_cmp(&(group->group_address), addr)) {
return group;
}
group = group->next;
}
/* to be clearer, we return NULL here instead of
* 'group' (which is also NULL at this point).
*/
return NULL;
}
/**
* Search for a specific igmp group and create a new one if not found-
*
* @param ifp the network interface for which to look
* @param addr the group ip address to search
* @return a struct igmp_group*,
* NULL on memory error.
*/
static struct igmp_group *
igmp_lookup_group(struct netif *ifp, const ip4_addr_t *addr)
{
struct igmp_group *group;
struct igmp_group *list_head = netif_igmp_data(ifp);
/* Search if the group already exists */
group = igmp_lookfor_group(ifp, addr);
if (group != NULL) {
/* Group already exists. */
return group;
}
/* Group doesn't exist yet, create a new one */
group = (struct igmp_group *)memp_malloc(MEMP_IGMP_GROUP);
if (group != NULL) {
ip4_addr_set(&(group->group_address), addr);
group->timer = 0; /* Not running */
group->group_state = IGMP_GROUP_NON_MEMBER;
group->last_reporter_flag = 0;
group->use = 0;
/* Ensure allsystems group is always first in list */
if (list_head == NULL) {
/* this is the first entry in linked list */
LWIP_ASSERT("igmp_lookup_group: first group must be allsystems",
(ip4_addr_cmp(addr, &allsystems) != 0));
group->next = NULL;
netif_set_client_data(ifp, LWIP_NETIF_CLIENT_DATA_INDEX_IGMP, group);
} else {
/* append _after_ first entry */
LWIP_ASSERT("igmp_lookup_group: all except first group must not be allsystems",
(ip4_addr_cmp(addr, &allsystems) == 0));
group->next = list_head->next;
list_head->next = group;
}
}
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_lookup_group: %sallocated a new group with address ", (group ? "" : "impossible to ")));
ip4_addr_debug_print(IGMP_DEBUG, addr);
LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", (void *)ifp));
return group;
}
/**
* Remove a group from netif's igmp group list, but don't free it yet
*
* @param group the group to remove from the netif's igmp group list
* @return ERR_OK if group was removed from the list, an err_t otherwise
*/
static err_t
igmp_remove_group(struct netif *netif, struct igmp_group *group)
{
err_t err = ERR_OK;
struct igmp_group *tmp_group;
/* Skip the first group in the list, it is always the allsystems group added in igmp_start() */
for (tmp_group = netif_igmp_data(netif); tmp_group != NULL; tmp_group = tmp_group->next) {
if (tmp_group->next == group) {
tmp_group->next = group->next;
break;
}
}
/* Group not found in netif's igmp group list */
if (tmp_group == NULL) {
err = ERR_ARG;
}
return err;
}
/**
* Called from ip_input() if a new IGMP packet is received.
*
* @param p received igmp packet, p->payload pointing to the igmp header
* @param inp network interface on which the packet was received
* @param dest destination ip address of the igmp packet
*/
void
igmp_input(struct pbuf *p, struct netif *inp, const ip4_addr_t *dest)
{
struct igmp_msg *igmp;
struct igmp_group *group;
struct igmp_group *groupref;
IGMP_STATS_INC(igmp.recv);
/* Note that the length CAN be greater than 8 but only 8 are used - All are included in the checksum */
if (p->len < IGMP_MINLEN) {
pbuf_free(p);
IGMP_STATS_INC(igmp.lenerr);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: length error\n"));
return;
}
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: message from "));
ip4_addr_debug_print(IGMP_DEBUG, &(ip4_current_header()->src));
LWIP_DEBUGF(IGMP_DEBUG, (" to address "));
ip4_addr_debug_print(IGMP_DEBUG, &(ip4_current_header()->dest));
LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", (void *)inp));
/* Now calculate and check the checksum */
igmp = (struct igmp_msg *)p->payload;
if (inet_chksum(igmp, p->len)) {
pbuf_free(p);
IGMP_STATS_INC(igmp.chkerr);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: checksum error\n"));
return;
}
/* Packet is ok so find an existing group */
group = igmp_lookfor_group(inp, dest); /* use the destination IP address of incoming packet */
/* If group can be found or create... */
if (!group) {
pbuf_free(p);
IGMP_STATS_INC(igmp.drop);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP frame not for us\n"));
return;
}
/* NOW ACT ON THE INCOMING MESSAGE TYPE... */
switch (igmp->igmp_msgtype) {
case IGMP_MEMB_QUERY:
/* IGMP_MEMB_QUERY to the "all systems" address ? */
if ((ip4_addr_cmp(dest, &allsystems)) && ip4_addr_isany(&igmp->igmp_group_address)) {
/* THIS IS THE GENERAL QUERY */
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: General IGMP_MEMB_QUERY on \"ALL SYSTEMS\" address (224.0.0.1) [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
if (igmp->igmp_maxresp == 0) {
IGMP_STATS_INC(igmp.rx_v1);
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: got an all hosts query with time== 0 - this is V1 and not implemented - treat as v2\n"));
igmp->igmp_maxresp = IGMP_V1_DELAYING_MEMBER_TMR;
} else {
IGMP_STATS_INC(igmp.rx_general);
}
groupref = netif_igmp_data(inp);
/* Do not send messages on the all systems group address! */
/* Skip the first group in the list, it is always the allsystems group added in igmp_start() */
if (groupref != NULL) {
groupref = groupref->next;
}
while (groupref) {
igmp_delaying_member(groupref, igmp->igmp_maxresp);
groupref = groupref->next;
}
} else {
/* IGMP_MEMB_QUERY to a specific group ? */
if (!ip4_addr_isany(&igmp->igmp_group_address)) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_MEMB_QUERY to a specific group "));
ip4_addr_debug_print(IGMP_DEBUG, &igmp->igmp_group_address);
if (ip4_addr_cmp(dest, &allsystems)) {
ip4_addr_t groupaddr;
LWIP_DEBUGF(IGMP_DEBUG, (" using \"ALL SYSTEMS\" address (224.0.0.1) [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
/* we first need to re-look for the group since we used dest last time */
ip4_addr_copy(groupaddr, igmp->igmp_group_address);
group = igmp_lookfor_group(inp, &groupaddr);
} else {
LWIP_DEBUGF(IGMP_DEBUG, (" with the group address as destination [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
}
if (group != NULL) {
IGMP_STATS_INC(igmp.rx_group);
igmp_delaying_member(group, igmp->igmp_maxresp);
} else {
IGMP_STATS_INC(igmp.drop);
}
} else {
IGMP_STATS_INC(igmp.proterr);
}
}
break;
case IGMP_V2_MEMB_REPORT:
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_V2_MEMB_REPORT\n"));
IGMP_STATS_INC(igmp.rx_report);
if (group->group_state == IGMP_GROUP_DELAYING_MEMBER) {
/* This is on a specific group we have already looked up */
group->timer = 0; /* stopped */
group->group_state = IGMP_GROUP_IDLE_MEMBER;
group->last_reporter_flag = 0;
}
break;
default:
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: unexpected msg %d in state %d on group %p on if %p\n",
igmp->igmp_msgtype, group->group_state, (void *)&group, (void *)inp));
IGMP_STATS_INC(igmp.proterr);
break;
}
pbuf_free(p);
return;
}
/**
* @ingroup igmp
* Join a group on one network interface.
*
* @param ifaddr ip address of the network interface which should join a new group
* @param groupaddr the ip address of the group which to join
* @return ERR_OK if group was joined on the netif(s), an err_t otherwise
*/
err_t
igmp_joingroup(const ip4_addr_t *ifaddr, const ip4_addr_t *groupaddr)
{
err_t err = ERR_VAL; /* no matching interface */
struct netif *netif;
/* make sure it is multicast address */
LWIP_ERROR("igmp_joingroup: attempt to join non-multicast address", ip4_addr_ismulticast(groupaddr), return ERR_VAL;);
LWIP_ERROR("igmp_joingroup: attempt to join allsystems address", (!ip4_addr_cmp(groupaddr, &allsystems)), return ERR_VAL;);
/* loop through netif's */
NETIF_FOREACH(netif) {
/* Should we join this interface ? */
if ((netif->flags & NETIF_FLAG_IGMP) && ((ip4_addr_isany(ifaddr) || ip4_addr_cmp(netif_ip4_addr(netif), ifaddr)))) {
err = igmp_joingroup_netif(netif, groupaddr);
if (err != ERR_OK) {
/* Return an error even if some network interfaces are joined */
/** @todo undo any other netif already joined */
return err;
}
}
}
return err;
}
/**
* @ingroup igmp
* Join a group on one network interface.
*
* @param netif the network interface which should join a new group
* @param groupaddr the ip address of the group which to join
* @return ERR_OK if group was joined on the netif, an err_t otherwise
*/
err_t
igmp_joingroup_netif(struct netif *netif, const ip4_addr_t *groupaddr)
{
struct igmp_group *group;
/* make sure it is multicast address */
LWIP_ERROR("igmp_joingroup_netif: attempt to join non-multicast address", ip4_addr_ismulticast(groupaddr), return ERR_VAL;);
LWIP_ERROR("igmp_joingroup_netif: attempt to join allsystems address", (!ip4_addr_cmp(groupaddr, &allsystems)), return ERR_VAL;);
/* make sure it is an igmp-enabled netif */
LWIP_ERROR("igmp_joingroup_netif: attempt to join on non-IGMP netif", netif->flags & NETIF_FLAG_IGMP, return ERR_VAL;);
/* find group or create a new one if not found */
group = igmp_lookup_group(netif, groupaddr);
if (group != NULL) {
/* This should create a new group, check the state to make sure */
if (group->group_state != IGMP_GROUP_NON_MEMBER) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup_netif: join to group not in state IGMP_GROUP_NON_MEMBER\n"));
} else {
/* OK - it was new group */
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup_netif: join to new group: "));
ip4_addr_debug_print(IGMP_DEBUG, groupaddr);
LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
/* If first use of the group, allow the group at the MAC level */
if ((group->use == 0) && (netif->igmp_mac_filter != NULL)) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup_netif: igmp_mac_filter(ADD "));
ip4_addr_debug_print(IGMP_DEBUG, groupaddr);
LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", (void *)netif));
netif->igmp_mac_filter(netif, groupaddr, NETIF_ADD_MAC_FILTER);
}
IGMP_STATS_INC(igmp.tx_join);
igmp_send(netif, group, IGMP_V2_MEMB_REPORT);
igmp_start_timer(group, IGMP_JOIN_DELAYING_MEMBER_TMR);
/* Need to work out where this timer comes from */
group->group_state = IGMP_GROUP_DELAYING_MEMBER;
}
/* Increment group use */
group->use++;
/* Join on this interface */
return ERR_OK;
} else {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup_netif: Not enough memory to join to group\n"));
return ERR_MEM;
}
}
/**
* @ingroup igmp
* Leave a group on one network interface.
*
* @param ifaddr ip address of the network interface which should leave a group
* @param groupaddr the ip address of the group which to leave
* @return ERR_OK if group was left on the netif(s), an err_t otherwise
*/
err_t
igmp_leavegroup(const ip4_addr_t *ifaddr, const ip4_addr_t *groupaddr)
{
err_t err = ERR_VAL; /* no matching interface */
struct netif *netif;
/* make sure it is multicast address */
LWIP_ERROR("igmp_leavegroup: attempt to leave non-multicast address", ip4_addr_ismulticast(groupaddr), return ERR_VAL;);
LWIP_ERROR("igmp_leavegroup: attempt to leave allsystems address", (!ip4_addr_cmp(groupaddr, &allsystems)), return ERR_VAL;);
/* loop through netif's */
NETIF_FOREACH(netif) {
/* Should we leave this interface ? */
if ((netif->flags & NETIF_FLAG_IGMP) && ((ip4_addr_isany(ifaddr) || ip4_addr_cmp(netif_ip4_addr(netif), ifaddr)))) {
err_t res = igmp_leavegroup_netif(netif, groupaddr);
if (err != ERR_OK) {
/* Store this result if we have not yet gotten a success */
err = res;
}
}
}
return err;
}
/**
* @ingroup igmp
* Leave a group on one network interface.
*
* @param netif the network interface which should leave a group
* @param groupaddr the ip address of the group which to leave
* @return ERR_OK if group was left on the netif, an err_t otherwise
*/
err_t
igmp_leavegroup_netif(struct netif *netif, const ip4_addr_t *groupaddr)
{
struct igmp_group *group;
/* make sure it is multicast address */
LWIP_ERROR("igmp_leavegroup_netif: attempt to leave non-multicast address", ip4_addr_ismulticast(groupaddr), return ERR_VAL;);
LWIP_ERROR("igmp_leavegroup_netif: attempt to leave allsystems address", (!ip4_addr_cmp(groupaddr, &allsystems)), return ERR_VAL;);
/* make sure it is an igmp-enabled netif */
LWIP_ERROR("igmp_leavegroup_netif: attempt to leave on non-IGMP netif", netif->flags & NETIF_FLAG_IGMP, return ERR_VAL;);
/* find group */
group = igmp_lookfor_group(netif, groupaddr);
if (group != NULL) {
/* Only send a leave if the flag is set according to the state diagram */
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup_netif: Leaving group: "));
ip4_addr_debug_print(IGMP_DEBUG, groupaddr);
LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
/* If there is no other use of the group */
if (group->use <= 1) {
/* Remove the group from the list */
igmp_remove_group(netif, group);
/* If we are the last reporter for this group */
if (group->last_reporter_flag) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup_netif: sending leaving group\n"));
IGMP_STATS_INC(igmp.tx_leave);
igmp_send(netif, group, IGMP_LEAVE_GROUP);
}
/* Disable the group at the MAC level */
if (netif->igmp_mac_filter != NULL) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup_netif: igmp_mac_filter(DEL "));
ip4_addr_debug_print(IGMP_DEBUG, groupaddr);
LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", (void *)netif));
netif->igmp_mac_filter(netif, groupaddr, NETIF_DEL_MAC_FILTER);
}
/* Free group struct */
memp_free(MEMP_IGMP_GROUP, group);
} else {
/* Decrement group use */
group->use--;
}
return ERR_OK;
} else {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup_netif: not member of group\n"));
return ERR_VAL;
}
}
/**
* The igmp timer function (both for NO_SYS=1 and =0)
* Should be called every IGMP_TMR_INTERVAL milliseconds (100 ms is default).
*/
void
igmp_tmr(void)
{
struct netif *netif;
NETIF_FOREACH(netif) {
struct igmp_group *group = netif_igmp_data(netif);
while (group != NULL) {
if (group->timer > 0) {
group->timer--;
if (group->timer == 0) {
igmp_timeout(netif, group);
}
}
group = group->next;
}
}
}
/**
* Called if a timeout for one group is reached.
* Sends a report for this group.
*
* @param group an igmp_group for which a timeout is reached
*/
static void
igmp_timeout(struct netif *netif, struct igmp_group *group)
{
/* If the state is IGMP_GROUP_DELAYING_MEMBER then we send a report for this group
(unless it is the allsystems group) */
if ((group->group_state == IGMP_GROUP_DELAYING_MEMBER) &&
(!(ip4_addr_cmp(&(group->group_address), &allsystems)))) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_timeout: report membership for group with address "));
ip4_addr_debug_print(IGMP_DEBUG, &(group->group_address));
LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", (void *)netif));
group->group_state = IGMP_GROUP_IDLE_MEMBER;
IGMP_STATS_INC(igmp.tx_report);
igmp_send(netif, group, IGMP_V2_MEMB_REPORT);
}
}
/**
* Start a timer for an igmp group
*
* @param group the igmp_group for which to start a timer
* @param max_time the time in multiples of IGMP_TMR_INTERVAL (decrease with
* every call to igmp_tmr())
*/
static void
igmp_start_timer(struct igmp_group *group, u8_t max_time)
{
#ifdef LWIP_RAND
group->timer = (u16_t)(max_time > 2 ? (LWIP_RAND() % max_time) : 1);
#else /* LWIP_RAND */
/* ATTENTION: use this only if absolutely necessary! */
group->timer = max_time / 2;
#endif /* LWIP_RAND */
if (group->timer == 0) {
group->timer = 1;
}
}
/**
* Delaying membership report for a group if necessary
*
* @param group the igmp_group for which "delaying" membership report
* @param maxresp query delay
*/
static void
igmp_delaying_member(struct igmp_group *group, u8_t maxresp)
{
if ((group->group_state == IGMP_GROUP_IDLE_MEMBER) ||
((group->group_state == IGMP_GROUP_DELAYING_MEMBER) &&
((group->timer == 0) || (maxresp < group->timer)))) {
igmp_start_timer(group, maxresp);
group->group_state = IGMP_GROUP_DELAYING_MEMBER;
}
}
/**
* Sends an IP packet on a network interface. This function constructs the IP header
* and calculates the IP header checksum. If the source IP address is NULL,
* the IP address of the outgoing network interface is filled in as source address.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
IP header and p->payload points to that IP header)
* @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
* IP address of the netif used to send is used as source address)
* @param dest the destination IP address to send the packet to
* @param netif the netif on which to send this packet
* @return ERR_OK if the packet was sent OK
* ERR_BUF if p doesn't have enough space for IP/LINK headers
* returns errors returned by netif->output
*/
static err_t
igmp_ip_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest, struct netif *netif)
{
/* This is the "router alert" option */
u16_t ra[2];
ra[0] = PP_HTONS(ROUTER_ALERT);
ra[1] = 0x0000; /* Router shall examine packet */
IGMP_STATS_INC(igmp.xmit);
return ip4_output_if_opt(p, src, dest, IGMP_TTL, 0, IP_PROTO_IGMP, netif, ra, ROUTER_ALERTLEN);
}
/**
* Send an igmp packet to a specific group.
*
* @param group the group to which to send the packet
* @param type the type of igmp packet to send
*/
static void
igmp_send(struct netif *netif, struct igmp_group *group, u8_t type)
{
struct pbuf *p = NULL;
struct igmp_msg *igmp = NULL;
ip4_addr_t src = *IP4_ADDR_ANY4;
ip4_addr_t *dest = NULL;
/* IP header + "router alert" option + IGMP header */
p = pbuf_alloc(PBUF_TRANSPORT, IGMP_MINLEN, PBUF_RAM);
if (p) {
igmp = (struct igmp_msg *)p->payload;
LWIP_ASSERT("igmp_send: check that first pbuf can hold struct igmp_msg",
(p->len >= sizeof(struct igmp_msg)));
ip4_addr_copy(src, *netif_ip4_addr(netif));
if (type == IGMP_V2_MEMB_REPORT) {
dest = &(group->group_address);
ip4_addr_copy(igmp->igmp_group_address, group->group_address);
group->last_reporter_flag = 1; /* Remember we were the last to report */
} else {
if (type == IGMP_LEAVE_GROUP) {
dest = &allrouters;
ip4_addr_copy(igmp->igmp_group_address, group->group_address);
}
}
if ((type == IGMP_V2_MEMB_REPORT) || (type == IGMP_LEAVE_GROUP)) {
igmp->igmp_msgtype = type;
igmp->igmp_maxresp = 0;
igmp->igmp_checksum = 0;
igmp->igmp_checksum = inet_chksum(igmp, IGMP_MINLEN);
igmp_ip_output_if(p, &src, dest, netif);
}
pbuf_free(p);
} else {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_send: not enough memory for igmp_send\n"));
IGMP_STATS_INC(igmp.memerr);
}
}
#endif /* LWIP_IPV4 && LWIP_IGMP */