lwip/src/core/ipv4/igmp.c

/*
 * 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.
*/

/************************************************************
In the spirit of LW (I hope)
-------------------------------------------------------------
note 1)
Although the rfc requires V1 AND V2 capability
we will only support v2 since now V1 is 5 years old
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
------------------------------------------------------------*/

/*-----------------------------------------------------------------------------
 * Includes
 *----------------------------------------------------------------------------*/

#include "lwip/debug.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/ip.h"
#include "lwip/inet.h"
#include "lwip/netif.h"
#include "lwip/icmp.h"
#include "lwip/udp.h"
#include "lwip/tcp.h"
#include "lwip/stats.h"
#include "lwip/igmp.h"

#include "arch/perf.h"

#include "string.h"

/* IGMP support available? */
#if defined(LWIP_IGMP) && (LWIP_IGMP > 0)

/*-----------------------------------------------------------------------------
 * Globales
 *----------------------------------------------------------------------------*/

struct igmp_group* GroupList;
struct igmp_stats  igmpstats;

struct ip_addr     allsystems;
struct ip_addr     allrouters;

/*-----------------------------------------------------------------------------
 * igmp_init
 *----------------------------------------------------------------------------*/
void igmp_init(void)
{ struct igmp_group* group;
  struct netif*      netif;
  
  LWIP_DEBUGF(IGMP_DEBUG, ("IGMP Initialising\n"));

  IP4_ADDR (&allsystems, 224, 0, 0, 1);
  IP4_ADDR (&allrouters, 224, 0, 0, 2);
  
  GroupList = NULL;  
  memset( &igmpstats, 0, sizeof(igmpstats));
  
  for( netif = netif_list; netif != NULL; netif = netif->next)
   { group = lookup_group (netif, &allsystems);
      
     if (group)
      { group->group_state = IDLE_MEMBER;
      
        // Allow the igmp messages at the MAC level
        if (netif->igmp_mac_filter!=NULL)
         { netif->igmp_mac_filter( netif, &allsystems, IGMP_ADD_MAC_FILTER);
           netif->igmp_mac_filter( netif, &allrouters, IGMP_ADD_MAC_FILTER);
         }
      }
   }

  // Start the 10 millisecond tick 
  // we can optimise this to only run when timers are active later on
  sys_timeout( IGMP_TICK, igmp_tick, NULL);
}

/*-----------------------------------------------------------------------------
 * lookfor_group
 *----------------------------------------------------------------------------*/
struct igmp_group * lookfor_group( struct netif *ifp, struct ip_addr *addr)
{ struct igmp_group *group = GroupList;
  
  while (group)
   { if ((group->interface == ifp) && (ip_addr_cmp (&(group->group_address), addr)))
      { return group;
      }
     group = group->next;
   }
   
  return group;
}

/*-----------------------------------------------------------------------------
 * lookup_group
 *----------------------------------------------------------------------------*/
struct igmp_group * lookup_group( struct netif *ifp, struct ip_addr *addr)
{ struct igmp_group *group = GroupList;
  
  while (group)
   { if ((group->interface == ifp) && (ip_addr_cmp (&(group->group_address), addr)))
      { return group;
      }
     group = group->next;
   }
   
  group = mem_malloc (sizeof (struct igmp_group));
  
  if (group)
   { group->interface          = ifp;
     ip_addr_set (&(group->group_address), addr);
     group->timer              = 0;        // Not running
     group->group_state        = NON_MEMBER;
     group->last_reporter_flag = 0;
     group->next               = GroupList;
     
     GroupList = group;
     
     LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %d  allocated a new group with address %x on if %x \n", __LINE__, (int) addr, (int) ifp));
   }
  else
   { LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %d  impossible to allocated a new group with address %x on if %x \n", __LINE__, (int) addr, (int) ifp));
   }
   
  return group;
}

/*-----------------------------------------------------------------------------
 * igmp_input
 *----------------------------------------------------------------------------*/
void igmp_input( struct pbuf *p, struct netif *inp, struct ip_addr *dest)
{ struct ip_hdr *    iphdr;
  struct igmpmsg*    igmp;
  struct igmp_group* group;
  struct igmp_group* groupref;
  
  iphdr = p->payload;  
  igmp  = (struct igmpmsg *)(((u8_t *)p->payload)+((u32_t)(IPH_HL(iphdr) * 4)));

  LWIP_DEBUGF(IGMP_DEBUG, ("igmp message to address %l \n", (long) dest->addr));

  if (p->len < IGMP_MINLEN)
   { // Nore that the length CAN be greater than 8 but only 8 are used - All are included in the checksum
     pbuf_free (p);
     igmpstats.igmp_length_err++;
     LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %x igmp length error\n", __LINE__));
     return;
   }

  // Now calculate and check the checksum
  if (inet_chksum (igmp, IGMP_MINLEN /*p->len*/))
   { pbuf_free (p);
     igmpstats.igmp_checksum_err++;
     LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %d igmp checksum error\n", __LINE__));
     return;
   }

  // Packet is ok so find the group (or create a new one)
  group = lookup_group (inp, dest);    // use the incoming IP address!
  
  // If group can be found or create...
  if (!group)
   { pbuf_free (p);
     LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %d igmp allocation error\n", __LINE__));
     return;
   }

  // NOW ACT ON THE INCOMING MESSAGE TYPE...

  // The membership query message goes to the all groups address
  // and it control block does not have state
  if ((IGMP_MEMB_QUERY == igmp->igmp_msgtype) && (ip_addr_cmp (dest, &allsystems)) && (igmp->igmp_group_address.addr == 0))
   { // THIS IS THE GENERAL QUERY
     LWIP_DEBUGF(IGMP_DEBUG, ("General IGMP_MEMB_QUERY on ALL SYSTEMS ADDRESS 224.0.0.1\n"));

     if (0 ==igmp->igmp_maxresp )
      { igmpstats.igmp_v1_rxed++;
        igmp->igmp_maxresp = 10;
        LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %d got an all hosts query with time== 0 - this is V1 and not implemented - treat as v2\n", __LINE__));
      }
      
     igmpstats.igmp_group_query_rxed++;
     groupref = GroupList;
     while (groupref)
      { if ((groupref->interface == inp) && (!(ip_addr_cmp (&(groupref->group_address), &allsystems))))
         { // Do not send messages on the all systems group address!
           if ((groupref->group_state == IDLE_MEMBER) || ((groupref->group_state == DELAYING_MEMBER) && (igmp->igmp_maxresp > groupref->timer)))
            { igmp_start_timer (groupref, (igmp->igmp_maxresp)/2);
              groupref->group_state = DELAYING_MEMBER;
            }
         }
        groupref = groupref->next;
      }
   }
  else
  if ((IGMP_MEMB_QUERY == igmp->igmp_msgtype) && ip_addr_cmp (dest, &allsystems) && (group->group_address.addr != 0))
   { LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %x got a  query to a specific group using the allsystems address \n", __LINE__));

     // we first need to re-lookup the group since we used dest last time
     group = lookup_group (inp, &igmp->igmp_group_address);    // use the incoming IP address!
     igmpstats.igmp_unicast_query++;

     if ((IDLE_MEMBER == group->group_state ) || ((DELAYING_MEMBER == group->group_state  ) && (igmp->igmp_maxresp > group->timer)))
      { igmp_start_timer (group, (igmp->igmp_maxresp)/2);
        group->group_state = DELAYING_MEMBER;
      }
   }
  else
  if ((IGMP_MEMB_QUERY == igmp->igmp_msgtype) && !(ip_addr_cmp (dest, &allsystems)) && (group->group_address.addr != 0))
   { LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %x got a  query to a specific group with the group address as destination \n", __LINE__));
   
     igmpstats.igmp_unicast_query++; /* This is the unicast query */
     if ((IDLE_MEMBER == group->group_state  ) || ((DELAYING_MEMBER == group->group_state  ) && (igmp->igmp_maxresp > group->timer)))
      { igmp_start_timer (group, (igmp->igmp_maxresp)/2);
        group->group_state = DELAYING_MEMBER;
      }
   }
  else
  if (IGMP_V2_MEMB_REPORT == igmp->igmp_msgtype )
   { LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c,Line %x got an IGMP_V2_MEMB_REPORT \n", __LINE__));
   
     igmpstats.report_rxed++;
     if (DELAYING_MEMBER == group->group_state )
      { // This is on a specific group we have already looked up
        group->timer = 0;    //stopped
        group->group_state = IDLE_MEMBER;
        group->last_reporter_flag = 0;
      }
   }
  else
   { LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input, Line %x unexpected msg %x in state %x on group %x  at interface %x\n", __LINE__, (int) igmp->igmp_msgtype, (int) group->group_state, (int) &group, (int) group->interface));
   }
   
  pbuf_free (p);
  return;
}

/*-----------------------------------------------------------------------------
 * igmp_joingroup
 *----------------------------------------------------------------------------*/
err_t igmp_joingroup( struct netif *ifp, struct ip_addr *groupaddr)
{ struct igmp_group *group;
  
  group = lookup_group (ifp, groupaddr);

  if (group)
   { // This should create a new group, check the state to make sure
     if (group->group_state != NON_MEMBER)
      { LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c Line %x join to group not in state NON_MEMBER\n", __LINE__));
        return ERR_OK;
      }

     // OK - it was new group
     igmpstats.igmp_joins++;
     
     LWIP_DEBUGF(IGMP_DEBUG, ("igmp join to new group\n"));
  
     if (ifp->igmp_mac_filter!=NULL)
      { ifp->igmp_mac_filter( ifp, groupaddr, IGMP_ADD_MAC_FILTER);
      }
     
     igmp_send( group, IGMP_V2_MEMB_REPORT);
     
     igmp_start_timer( group, 5);
     
     // Need to work out where this timer comes from
     group->group_state = DELAYING_MEMBER;
     
     return ERR_OK;
   }
  
  return ERR_MEM;
}

/*-----------------------------------------------------------------------------
 * igmp_leavegroup
 *----------------------------------------------------------------------------*/
err_t igmp_leavegroup( struct netif *ifp, struct ip_addr *groupaddr)
{ struct igmp_group *group;
  
  group = lookup_group (ifp, groupaddr);

  if (group)
   { // Only send a leave if the flag is set according to the state diagram
     if (group->last_reporter_flag)
      { LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c Line %x Leaving group\n", __LINE__));
        igmpstats.igmp_leave_sent++;
        igmp_send( group, IGMP_LEAVE_GROUP);
      }
      
     // The block is not deleted since the group still exists and we may rejoin
     group->last_reporter_flag = 0;
     group->group_state        = NON_MEMBER;
     group->timer              = 0;
     
     if (ifp->igmp_mac_filter!=NULL)
      { ifp->igmp_mac_filter( ifp, groupaddr, IGMP_DEL_MAC_FILTER);
      }
     
     return ERR_OK;
   }

  return ERR_MEM;
}

/*-----------------------------------------------------------------------------
 * igmp_tick
 *----------------------------------------------------------------------------*/
void igmp_tick(void *arg)
{ struct igmp_group *group = GroupList;

  arg = arg;

  while (group)
   { if (group->timer != 0)
      { group->timer -=1;
        if (group->timer == 0)
         { igmp_timeout (group);
         }
      }
     group = group->next;
   }

  // 100 millisecond tick handler
  // go down the list of all groups here and check for timeouts
  sys_timeout (IGMP_TICK, igmp_tick, NULL);
}

/*-----------------------------------------------------------------------------
 * igmp_timeout
 *----------------------------------------------------------------------------*/
void igmp_timeout( struct igmp_group *group)
{ // If the state is DELAYING_MEMBER then we send a report for this group
  LWIP_DEBUGF(IGMP_DEBUG, ("igmp.c, got a timeout\n"));

  if (DELAYING_MEMBER == group->group_state)
   {  igmp_send( group, IGMP_V2_MEMB_REPORT);
   }
}

/*-----------------------------------------------------------------------------
 * igmp_start_timer
 *----------------------------------------------------------------------------*/
void igmp_start_timer( struct igmp_group *group, u8_t max_time)
{ // Important !! this should be random 0 -> max_time
  // find out how to do this
  group->timer = max_time;
}

/*-----------------------------------------------------------------------------
 * igmp_stop_timer
 *----------------------------------------------------------------------------*/
void igmp_stop_timer( struct igmp_group *group)
{ group->timer = 0;
}

/*-----------------------------------------------------------------------------
 * igmp_ip_output_if
 * 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.
 *----------------------------------------------------------------------------*/
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)
{ static struct ip_hdr * iphdr = NULL;
  static u16_t           ip_id = 0;
  u16_t *                ra    = NULL;

  // First write in the "router alert"
  if (pbuf_header (p, ROUTER_ALERTLEN))
   { LWIP_DEBUGF(IGMP_DEBUG, ("igmp_ip_output_if: not enough room for IP header in pbuf\n"));
     return ERR_BUF;
   }

  // This is the "router alert" option
  ra    = p->payload;
  ra[0] = htons (0x9404);
  ra[1] = 0x0000;

  // now the normal ip header
  if (pbuf_header (p, IP_HLEN))
   { LWIP_DEBUGF(IGMP_DEBUG, ("igmp_ip_output_if: not enough room for IP header in pbuf\n"));
     return ERR_BUF;
   }

  iphdr = p->payload;
  if (dest != IP_HDRINCL)
   { iphdr->_ttl_proto = (proto<<8);
     iphdr->_ttl_proto |= ttl;

     /*  iphdr->dest = dest->addr; */
     ip_addr_set (&(iphdr->dest), dest);
#ifdef HAVE_BITFIELDS
     iphdr->_v_hl_tos |= ((IP_HLEN+ ROUTER_ALERTLEN)/4)<<16;
     iphdr->_v_hl_tos |= 4<<24;
#else
     iphdr->_v_hl_tos = (4 << 4) | ((IP_HLEN + ROUTER_ALERTLEN)/ 4 & 0xf);
#endif /* HAVE_BITFIELDS */

     iphdr->_v_hl_tos |= 0;
     iphdr->_len       = htons (p->tot_len);
     iphdr->_offset    = htons (0);
     iphdr->_id        = htons (ip_id++);

     if (ip_addr_isany (src))
      { ip_addr_set (&(iphdr->src), &(netif->ip_addr));
      }
     else
      { ip_addr_set (&(iphdr->src), src);
      }

     iphdr->_chksum = 0;
     iphdr->_chksum = inet_chksum (iphdr, IP_HLEN + ROUTER_ALERTLEN);
   }
  else
   { dest = &(iphdr->dest);
   }

#if IP_DEBUG
  ip_debug_print (p);
#endif

  LWIP_DEBUGF(IGMP_DEBUG, ("IGMP sending to netif %x \n", (int) netif));

  return netif->output (netif, p, dest);
}

/*-----------------------------------------------------------------------------
 * igmp_send
 *----------------------------------------------------------------------------*/
void igmp_send( struct igmp_group *group, u8_t type)
{ struct pbuf*    p    = NULL;
  struct igmpmsg* igmp = NULL;
  struct ip_addr  src  = {0};
  struct ip_addr* dest = NULL;

  /* IP header + IGMP header */
  p = pbuf_alloc( PBUF_TRANSPORT, IGMP_MINLEN, PBUF_RAM);
  
  if (p)
   { igmp = p->payload;
     ip_addr_set (&src, &((group->interface)->ip_addr));
     
     if (IGMP_V2_MEMB_REPORT == type)
      { dest = &(group->group_address);
        igmpstats.report_sent++;
        ip_addr_set (&(igmp->igmp_group_address), &(group->group_address));
        group->last_reporter_flag = 1; // Remember we were the last to report
      }
     else
     if (IGMP_LEAVE_GROUP == type)
      { dest = &allrouters;
        ip_addr_set (&(igmp->igmp_group_address), &(group->group_address));
      }

     if ((IGMP_V2_MEMB_REPORT == type) || (IGMP_LEAVE_GROUP == type))
      { 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, IGMP_TTL, IP_PROTO_IGMP, group->interface);
      }
      
     pbuf_free (p);
   }
  else
   { LWIP_DEBUGF(IGMP_DEBUG, ("IGMP, not enough memory for igmp_send\n"));
   }
}

#endif /* LWIP_IGMP */