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minix/lib/liblwip/core/ipv4/igmp.c
Tomas Hruby abab24b785 LWIP - liblwip 
lwip-1.4.0-rc1 imported as liblwip
2011-04-07 07:43:36 +00:00

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/**
* @file
* IGMP - Internet Group Management Protocol
*
*/
/*
* 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_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/icmp.h"
#include "lwip/udp.h"
#include "lwip/tcp.h"
#include "lwip/stats.h"
#include "string.h"
/*
* IGMP constants
*/
#define IGMP_TTL 1
#define IGMP_MINLEN 8
#define ROUTER_ALERT 0x9404
#define ROUTER_ALERTLEN 4
/*
* IGMP message types, including version number.
*/
#define IGMP_MEMB_QUERY 0x11 /* Membership query */
#define IGMP_V1_MEMB_REPORT 0x12 /* Ver. 1 membership report */
#define IGMP_V2_MEMB_REPORT 0x16 /* Ver. 2 membership report */
#define IGMP_LEAVE_GROUP 0x17 /* Leave-group message */
/* Group membership states */
#define IGMP_GROUP_NON_MEMBER 0
#define IGMP_GROUP_DELAYING_MEMBER 1
#define IGMP_GROUP_IDLE_MEMBER 2
/**
* IGMP packet format.
*/
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/bpstruct.h"
#endif
PACK_STRUCT_BEGIN
struct igmp_msg {
PACK_STRUCT_FIELD(u8_t igmp_msgtype);
PACK_STRUCT_FIELD(u8_t igmp_maxresp);
PACK_STRUCT_FIELD(u16_t igmp_checksum);
PACK_STRUCT_FIELD(ip_addr_p_t igmp_group_address);
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/epstruct.h"
#endif
static struct igmp_group *igmp_lookup_group(struct netif *ifp, ip_addr_t *addr);
static err_t igmp_remove_group(struct igmp_group *group);
static void igmp_timeout( struct igmp_group *group);
static void igmp_start_timer(struct igmp_group *group, u8_t max_time);
static void igmp_stop_timer(struct igmp_group *group);
static void igmp_delaying_member(struct igmp_group *group, u8_t maxresp);
static err_t igmp_ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest, struct netif *netif);
static void igmp_send(struct igmp_group *group, u8_t type);
static struct igmp_group* igmp_group_list;
static ip_addr_t allsystems;
static ip_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);
}
#ifdef LWIP_DEBUG
/**
* Dump global IGMP groups list
*/
void
igmp_dump_group_list()
{
struct igmp_group *group = igmp_group_list;
while (group != NULL) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_dump_group_list: [%"U32_F"] ", (u32_t)(group->group_state)));
ip_addr_debug_print(IGMP_DEBUG, &group->group_address);
LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", group->netif));
group = group->next;
}
LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
}
#else
#define igmp_dump_group_list()
#endif /* LWIP_DEBUG */
/**
* 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", 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 "));
ip_addr_debug_print(IGMP_DEBUG, &allsystems);
LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", netif));
netif->igmp_mac_filter(netif, &allsystems, IGMP_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 = igmp_group_list;
struct igmp_group *prev = NULL;
struct igmp_group *next;
/* look for groups joined on this interface further down the list */
while (group != NULL) {
next = group->next;
/* is it a group joined on this interface? */
if (group->netif == netif) {
/* is it the first group of the list? */
if (group == igmp_group_list) {
igmp_group_list = next;
}
/* is there a "previous" group defined? */
if (prev != NULL) {
prev->next = next;
}
/* disable the group at the MAC level */
if (netif->igmp_mac_filter != NULL) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_stop: igmp_mac_filter(DEL "));
ip_addr_debug_print(IGMP_DEBUG, &group->group_address);
LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", netif));
netif->igmp_mac_filter(netif, &(group->group_address), IGMP_DEL_MAC_FILTER);
}
/* free group */
memp_free(MEMP_IGMP_GROUP, group);
} else {
/* change the "previous" */
prev = 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 = igmp_group_list;
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_report_groups: sending IGMP reports on if %p\n", netif));
while (group != NULL) {
if (group->netif == netif) {
igmp_delaying_member(group, IGMP_JOIN_DELAYING_MEMBER_TMR);
}
group = group->next;
}
}
/**
* Search for a group in the global 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, ip_addr_t *addr)
{
struct igmp_group *group = igmp_group_list;
while (group != NULL) {
if ((group->netif == ifp) && (ip_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.
*/
struct igmp_group *
igmp_lookup_group(struct netif *ifp, ip_addr_t *addr)
{
struct igmp_group *group = igmp_group_list;
/* 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) {
group->netif = ifp;
ip_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;
group->next = igmp_group_list;
igmp_group_list = group;
}
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_lookup_group: %sallocated a new group with address ", (group?"":"impossible to ")));
ip_addr_debug_print(IGMP_DEBUG, addr);
LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", ifp));
return group;
}
/**
* Remove a group in the global igmp_group_list
*
* @param group the group to remove from the global igmp_group_list
* @return ERR_OK if group was removed from the list, an err_t otherwise
*/
static err_t
igmp_remove_group(struct igmp_group *group)
{
err_t err = ERR_OK;
/* Is it the first group? */
if (igmp_group_list == group) {
igmp_group_list = group->next;
} else {
/* look for group further down the list */
struct igmp_group *tmpGroup;
for (tmpGroup = igmp_group_list; tmpGroup != NULL; tmpGroup = tmpGroup->next) {
if (tmpGroup->next == group) {
tmpGroup->next = group->next;
break;
}
}
/* Group not found in the global igmp_group_list */
if (tmpGroup == NULL)
err = ERR_ARG;
}
/* free group */
memp_free(MEMP_IGMP_GROUP, group);
return err;
}
/**
* Called from ip_input() if a new IGMP packet is received.
*
* @param p received igmp packet, p->payload pointing to the ip 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, ip_addr_t *dest)
{
struct ip_hdr * iphdr;
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 */
iphdr = (struct ip_hdr *)p->payload;
if (pbuf_header(p, -(s16_t)(IPH_HL(iphdr) * 4)) || (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 "));
ip_addr_debug_print(IGMP_DEBUG, &(iphdr->src));
LWIP_DEBUGF(IGMP_DEBUG, (" to address "));
ip_addr_debug_print(IGMP_DEBUG, &(iphdr->dest));
LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", 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 ((ip_addr_cmp(dest, &allsystems)) && ip_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 = igmp_group_list;
while (groupref) {
/* Do not send messages on the all systems group address! */
if ((groupref->netif == inp) && (!(ip_addr_cmp(&(groupref->group_address), &allsystems)))) {
igmp_delaying_member(groupref, igmp->igmp_maxresp);
}
groupref = groupref->next;
}
} else {
/* IGMP_MEMB_QUERY to a specific group ? */
if (!ip_addr_isany(&igmp->igmp_group_address)) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_MEMB_QUERY to a specific group "));
ip_addr_debug_print(IGMP_DEBUG, &igmp->igmp_group_address);
if (ip_addr_cmp(dest, &allsystems)) {
ip_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 */
ip_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, &group, group->netif));
IGMP_STATS_INC(igmp.proterr);
break;
}
}
pbuf_free(p);
return;
}
/**
* 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(ip_addr_t *ifaddr, ip_addr_t *groupaddr)
{
err_t err = ERR_VAL; /* no matching interface */
struct igmp_group *group;
struct netif *netif;
/* make sure it is multicast address */
LWIP_ERROR("igmp_joingroup: attempt to join non-multicast address", ip_addr_ismulticast(groupaddr), return ERR_VAL;);
LWIP_ERROR("igmp_joingroup: attempt to join allsystems address", (!ip_addr_cmp(groupaddr, &allsystems)), return ERR_VAL;);
/* loop through netif's */
netif = netif_list;
while (netif != NULL) {
/* Should we join this interface ? */
if ((netif->flags & NETIF_FLAG_IGMP) && ((ip_addr_isany(ifaddr) || ip_addr_cmp(&(netif->ip_addr), ifaddr)))) {
/* 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: join to group not in state IGMP_GROUP_NON_MEMBER\n"));
} else {
/* OK - it was new group */
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup: join to new group: "));
ip_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: igmp_mac_filter(ADD "));
ip_addr_debug_print(IGMP_DEBUG, groupaddr);
LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", netif));
netif->igmp_mac_filter(netif, groupaddr, IGMP_ADD_MAC_FILTER);
}
IGMP_STATS_INC(igmp.tx_join);
igmp_send(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 */
err = ERR_OK;
} else {
/* Return an error even if some network interfaces are joined */
/** @todo undo any other netif already joined */
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup: Not enought memory to join to group\n"));
return ERR_MEM;
}
}
/* proceed to next network interface */
netif = netif->next;
}
return err;
}
/**
* 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(ip_addr_t *ifaddr, ip_addr_t *groupaddr)
{
err_t err = ERR_VAL; /* no matching interface */
struct igmp_group *group;
struct netif *netif;
/* make sure it is multicast address */
LWIP_ERROR("igmp_leavegroup: attempt to leave non-multicast address", ip_addr_ismulticast(groupaddr), return ERR_VAL;);
LWIP_ERROR("igmp_leavegroup: attempt to leave allsystems address", (!ip_addr_cmp(groupaddr, &allsystems)), return ERR_VAL;);
/* loop through netif's */
netif = netif_list;
while (netif != NULL) {
/* Should we leave this interface ? */
if ((netif->flags & NETIF_FLAG_IGMP) && ((ip_addr_isany(ifaddr) || ip_addr_cmp(&(netif->ip_addr), ifaddr)))) {
/* 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: Leaving group: "));
ip_addr_debug_print(IGMP_DEBUG, groupaddr);
LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
/* If there is no other use of the group */
if (group->use <= 1) {
/* If we are the last reporter for this group */
if (group->last_reporter_flag) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: sending leaving group\n"));
IGMP_STATS_INC(igmp.tx_leave);
igmp_send(group, IGMP_LEAVE_GROUP);
}
/* Disable the group at the MAC level */
if (netif->igmp_mac_filter != NULL) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: igmp_mac_filter(DEL "));
ip_addr_debug_print(IGMP_DEBUG, groupaddr);
LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", netif));
netif->igmp_mac_filter(netif, groupaddr, IGMP_DEL_MAC_FILTER);
}
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: remove group: "));
ip_addr_debug_print(IGMP_DEBUG, groupaddr);
LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
/* Free the group */
igmp_remove_group(group);
} else {
/* Decrement group use */
group->use--;
}
/* Leave on this interface */
err = ERR_OK;
} else {
/* It's not a fatal error on "leavegroup" */
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup: not member of group\n"));
}
}
/* proceed to next network interface */
netif = netif->next;
}
return err;
}
/**
* 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 igmp_group *group = igmp_group_list;
while (group != NULL) {
if (group->timer > 0) {
group->timer--;
if (group->timer == 0) {
igmp_timeout(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 igmp_group *group)
{
/* If the state is IGMP_GROUP_DELAYING_MEMBER then we send a report for this group */
if (group->group_state == IGMP_GROUP_DELAYING_MEMBER) {
LWIP_DEBUGF(IGMP_DEBUG, ("igmp_timeout: report membership for group with address "));
ip_addr_debug_print(IGMP_DEBUG, &(group->group_address));
LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", group->netif));
IGMP_STATS_INC(igmp.tx_report);
igmp_send(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)
{
/* ensure the input value is > 0 */
if (max_time == 0) {
max_time = 1;
}
/* ensure the random value is > 0 */
group->timer = (LWIP_RAND() % (max_time - 1)) + 1;
}
/**
* Stop a timer for an igmp_group
*
* @param group the igmp_group for which to stop the timer
*/
static void
igmp_stop_timer(struct igmp_group *group)
{
group->timer = 0;
}
/**
* 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 == 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 == IP_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 ttl the TTL value to be set in the IP header
* @param proto the PROTOCOL to be set in the IP header
* @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, ip_addr_t *src, ip_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 ip_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 igmp_group *group, u8_t type)
{
struct pbuf* p = NULL;
struct igmp_msg* igmp = NULL;
ip_addr_t src = *IP_ADDR_ANY;
ip_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)));
ip_addr_copy(src, group->netif->ip_addr);
if (type == IGMP_V2_MEMB_REPORT) {
dest = &(group->group_address);
ip_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;
ip_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, group->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_IGMP */
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