text: /**
   * 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.
  **/
  
  #ifndef __LWIP_IGMP_H__
  #define __LWIP_IGMP_H__
  
  #include "lwip/opt.h"
  #include "lwip/ip_addr.h"
  #include "lwip/netif.h"
  #include "lwip/pbuf.h"
  
  #if LWIP_IGMP /* don't build if not configured for use in lwipopts.h */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /* 
   * IGMP constants
   */
  #define IP_PROTO_IGMP                  2
  #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      */
  
  /* IGMP timer */
  #define IGMP_TMR_INTERVAL              100 /* Milliseconds */
  #define IGMP_V1_DELAYING_MEMBER_TMR   (1000/IGMP_TMR_INTERVAL)
  #define IGMP_JOIN_DELAYING_MEMBER_TMR (500 /IGMP_TMR_INTERVAL)
  
  /* MAC Filter Actions */
  #define IGMP_DEL_MAC_FILTER            0
  #define IGMP_ADD_MAC_FILTER            1
  
  /* 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(struct ip_addr igmp_group_address);
  } PACK_STRUCT_STRUCT;
  PACK_STRUCT_END
  #ifdef PACK_STRUCT_USE_INCLUDES
  #  include "arch/epstruct.h"
  #endif
  
  /* 
   * now a group structure - there is
   * a list of groups for each interface
   * these should really be linked from the interface, but
   * if we keep them separate we will not affect the lwip original code
   * too much
   * 
   * There will be a group for the all systems group address but this 
   * will not run the state machine as it is used to kick off reports
   * from all the other groups
   */
  
  struct igmp_group {
    struct igmp_group *next;
    struct netif      *interface;
    struct ip_addr     group_address;
    u8_t               last_reporter_flag; /* signifies we were the last person to report */
    u8_t               group_state;
    u16_t              timer;
    u8_t               use; /* counter of simultaneous uses */
  };
  
  
  /*  Prototypes */
  void   igmp_init(void);
  
  err_t  igmp_start( struct netif *netif);
  
  err_t  igmp_stop( struct netif *netif);
  
  void   igmp_report_groups( struct netif *netif);
  
  struct igmp_group *igmp_lookfor_group( struct netif *ifp, struct ip_addr *addr);
  
  struct igmp_group *igmp_lookup_group( struct netif *ifp, struct ip_addr *addr);
  
  err_t  igmp_remove_group( struct igmp_group *group);
  
  void   igmp_input( struct pbuf *p, struct netif *inp, struct ip_addr *dest);
  
  err_t  igmp_joingroup( struct ip_addr *ifaddr, struct ip_addr *groupaddr);
  
  err_t  igmp_leavegroup( struct ip_addr *ifaddr, struct ip_addr *groupaddr);
  
  void   igmp_tmr(void);
  
  void   igmp_timeout( struct igmp_group *group);
  
  void   igmp_start_timer( struct igmp_group *group, u8_t max_time);
  
  void   igmp_stop_timer( struct igmp_group *group);
  
  void   igmp_delaying_member( struct igmp_group *group, u8_t maxresp);
  
  err_t  igmp_ip_output_if( struct pbuf *p, struct ip_addr *src, struct ip_addr *dest, u8_t ttl, u8_t proto, struct netif *netif);
  
  void   igmp_send( struct igmp_group *group, u8_t type);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* LWIP_IGMP */
  
  #endif /* __LWIP_IGMP_H__ */
  