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igmpproxy

    1: /*
    2: **  igmpproxy - IGMP proxy based multicast router 
    3: **  Copyright (C) 2005 Johnny Egeland <johnny@rlo.org>
    4: **
    5: **  This program is free software; you can redistribute it and/or modify
    6: **  it under the terms of the GNU General Public License as published by
    7: **  the Free Software Foundation; either version 2 of the License, or
    8: **  (at your option) any later version.
    9: **
   10: **  This program is distributed in the hope that it will be useful,
   11: **  but WITHOUT ANY WARRANTY; without even the implied warranty of
   12: **  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   13: **  GNU General Public License for more details.
   14: **
   15: **  You should have received a copy of the GNU General Public License
   16: **  along with this program; if not, write to the Free Software
   17: **  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   18: **
   19: **----------------------------------------------------------------------------
   20: **
   21: **  This software is derived work from the following software. The original
   22: **  source code has been modified from it's original state by the author
   23: **  of igmpproxy.
   24: **
   25: **  smcroute 0.92 - Copyright (C) 2001 Carsten Schill <carsten@cschill.de>
   26: **  - Licensed under the GNU General Public License, version 2
   27: **  
   28: **  mrouted 3.9-beta3 - COPYRIGHT 1989 by The Board of Trustees of 
   29: **  Leland Stanford Junior University.
   30: **  - Original license can be found in the Stanford.txt file.
   31: **
   32: */
   33: /**
   34: *   mcgroup contains functions for joining and leaving multicast groups.
   35: *
   36: */
   37: 
   38: #include "igmpproxy.h"
   39:        
   40: 
   41: /**
   42: *   Common function for joining or leaving a MCast group.
   43: */
   44: static int joinleave( int Cmd, int UdpSock, struct IfDesc *IfDp, uint32_t mcastaddr ) {
   45:     struct ip_mreq CtlReq;
   46:     const char *CmdSt = Cmd == 'j' ? "join" : "leave";
   47:     
   48:     memset(&CtlReq, 0, sizeof(CtlReq));
   49:     CtlReq.imr_multiaddr.s_addr = mcastaddr;
   50:     CtlReq.imr_interface.s_addr = IfDp->InAdr.s_addr;
   51:     
   52:     {
   53:         my_log( LOG_NOTICE, 0, "%sMcGroup: %s on %s", CmdSt, 
   54:             inetFmt( mcastaddr, s1 ), IfDp ? IfDp->Name : "<any>" );
   55:     }
   56:     
   57:     if( setsockopt( UdpSock, IPPROTO_IP, 
   58:           Cmd == 'j' ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, 
   59:           (void *)&CtlReq, sizeof( CtlReq ) ) ) 
   60:     {
   61:         my_log( LOG_WARNING, errno, "MRT_%s_MEMBERSHIP failed", Cmd == 'j' ? "ADD" : "DROP" );
   62:         return 1;
   63:     }
   64:     
   65:     return 0;
   66: }
   67: 
   68: /**
   69: *   Joins the MC group with the address 'McAdr' on the interface 'IfName'. 
   70: *   The join is bound to the UDP socket 'UdpSock', so if this socket is 
   71: *   closed the membership is dropped.
   72: *          
   73: *   @return 0 if the function succeeds, 1 if parameters are wrong or the join fails
   74: */
   75: int joinMcGroup( int UdpSock, struct IfDesc *IfDp, uint32_t mcastaddr ) {
   76:     return joinleave( 'j', UdpSock, IfDp, mcastaddr );
   77: }
   78: 
   79: /**
   80: *   Leaves the MC group with the address 'McAdr' on the interface 'IfName'. 
   81: *          
   82: *   @return 0 if the function succeeds, 1 if parameters are wrong or the join fails
   83: */
   84: int leaveMcGroup( int UdpSock, struct IfDesc *IfDp, uint32_t mcastaddr ) {
   85:     return joinleave( 'l', UdpSock, IfDp, mcastaddr );
   86: }