David Smart
minor derivative to reduce compiler warnings and tag read-only parameters as const.
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Diff: core/ipv4/igmp.c
- Revision:
- 0:51ac1d130fd4
- Child:
- 8:f9d0ac9dd036
diff -r 000000000000 -r 51ac1d130fd4 core/ipv4/igmp.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/core/ipv4/igmp.c Fri Jun 22 09:25:39 2012 +0000
@@ -0,0 +1,817 @@
+/**
+ * @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 0x9404U
+#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 */