mh.c

mobile ip 源程序 对移动ip 的人员有用~！

     mhstats.idmismatch++;
     if (debug > 0)  {
       fprintf(stderr, "Id mismatch -- Reply ignored.\n");
     }
      return;
   }

   /* Check whether a valid reply */
   if (reply->type != REGREPLYTYPE || len < sizeof(struct regreply) ||
       !IsOurAgent(reply->ha) || !IsOurAddress(reply->homeaddr) ||
     ((reply->code<16 || reply->code>127) && 
      !(authoffset=authextfound(msg, len, 1)))) {
	  mhstats.badregreply++;
	  if (debug > 0)  {
	   fprintf(stderr, "Bad structure -- Reply ignored.\n");
	  }
	  return;
       }

   if ((reply->code<16 || reply->code>127) && 
	      !authok(msg, len, authoffset, Myinfo.secret, Myinfo.secretlen,Myinfo.SPIval))
     {
       mhstats.authfailed++;
       if (debug > 0)  {
	 fprintf(stderr, "Authentication failed -- Reply ignored.\n");
       }
       return;
     }
   
    

   Myinfo.status &= ~AWAITINGREPLY;
  
   if (reply->code == 0 || reply->code == 1)  {
      /* Our service request was approved */
     
     mhstats.regsuccessful++;
     if (reply->lifetime == 0)  
       {
	 /* deregistration approved */
	 /* Timer won't be running now */
	 Myinfo.timeleft = 0;
	 Myinfo.status |= DEREGISTERED;
       } 
     else  
       {
	 Myinfo.timeleft = reply->lifetime;
	 Myinfo.status |= REGISTERED;
	 
	 if((Myinfo.status & 0x03) == ASPOPUP)
	   {
	     lowifaceset(Myinfo.infname,Myinfo.homeaddr,Myinfo.homenetmask);
	     lowifaceset("dummy",Myinfo.coaddr,Myinfo.foreignnetmask);
	     lowhwaddrreq(Myinfo.infname,hwaddr);
	     lowARPreq(PROXY, Myinfo.coaddr, hwaddr);
	     lowrtset(Myinfo.coaddr, "dummy", ADDRT);
	   }
       }
   }
 
   else /* Rejection */  
     {
       /* If we are not yet registered then rejection might be due to ID mismatch, 
	  so without waiting for timer to go off,send registration */
       if(!(Myinfo.status & REGISTERED))
	 {
	   Myinfo.status |= AWAITINGREPLY;
	   Myinfo.timeleft = RETRYINTERVAL;
	   sendRegisterMe((int) 0, Myinfo.flags,Myinfo.lifetime,Myinfo.homeaddr, 
			    Myinfo.homeagent, Myinfo.coaddr);
	 }
       
       mhstats.regfailed++;
   }
   
}


/*Check whether received router discovery message is valid
  and cannot be ignored
  */
int cannotignore(char *msg, u_long *src, int len)
{
  struct youarehere *urh;
  char *p;
  struct icmp *icp;
  unsigned long *addr;
  
  /* We first check weather message is not corrupt or invalid */
  icp = (struct icmp*)msg;

  if(icp->type != ROUTERADVTYPE)
    {
      if(debug>1)
	fprintf(stderr,"Not a router discovery message\n");
      return FALSE;
    }

  urh = (struct youarehere*)(msg + SIZE_ICMP_HDR + 
			     4*(icp->addr_entry_size)*(icp->addrnum));
  len -= SIZE_ICMP_HDR +  4*(icp->addr_entry_size)*(icp->addrnum);

  
  if(urh->type != YOUAREHERETYPE || len <(sizeof(struct youarehere) + (urh->length-6)))
     {
       fprintf(stderr,"Rt discovery message is too short or type mismatch\n");
       return FALSE;
     }
      
  p = msg + SIZE_ICMP_HDR +  4*(icp->addr_entry_size)*(icp->addrnum)
    + sizeof(struct youarehere);
          
  addr = (unsigned long *) p;

  if (debug > 2)  {
    int i;   
    fprintf(stderr, "Rt. discovery  addrnum = %d, flags = %x  seqno = %d lifetime = %d\n",
	      (urh->length-6)/4, urh->flags,urh->seqno,urh->lifetime);
      for (i = 0; i < (urh->length-6)/4; i++)
      	fprintf(stderr, "Address %lx\n", htonl(*(addr + i)));
   }

  if((IsOurAgent(*addr) && (urh->flags & MSHFLAG))
     ||(!IsOurAgent(*addr) && (urh->flags & MSFFLAG)&&
	(!(urh->flags & MSBFLAG))&& urh->lifetime !=0))
    {
      *src = *addr;
      return TRUE;
    }

  else return FALSE;
}



/* This function decides which action should be taken: HOMEACTION,
   FOREIGNACTION or POPUPACTION. It uses PickupURheres() to 
   get any received router die]scovery message */

void dsn_maker(int sockid)
{
  unsigned long ipaddr,src,gw;
  short i,heard_no_adv;
  char dev[10], *p;
  static char msg[256];
  unsigned int msglen,fromlen;
  struct sockaddr_in from;
  struct youarehere *urh;
  fd_set fdvec;
  static struct timeval tv;
  static struct icmp *icp;
  static struct iphdr *ip;
  u_short iphdrlen;
  
  msglen = 0;
  bzero(msg,sizeof(msg));
  bzero((void*)&from,sizeof(struct sockaddr_in));
  if(!doit)Dminfo.action = 0;
  
  if(debug >2)
    fprintf(stderr,"Decision Maker with doit = %d\n",doit);

  if(lowdefifcreq(&ipaddr,&gw,dev)<0)
    {
      fprintf(stderr,"lowdefifcreq failed\n");
      return;
    }

  if(debug >2)
    {
       fprintf(stderr,"Default interface address %lx Interface name %s Gateway : %lx\n",
	      ipaddr, dev, gw);
    }
  

  heard_no_adv = TRUE;

  for(i=0;i<MAXOVERLAP;i++)
    {
      FD_ZERO(&fdvec);
      FD_SET(sockid,&fdvec);
      tv.tv_sec = 0;
      tv.tv_usec = 0;
      
      if(select(FD_SETSIZE,&fdvec,NULL,NULL,&tv)<0)
	{
	  if(errno == EINTR); /* This is expected since alarm is ruuning so do nothing */
	  else
	    perror("select() failed in dsn_maker()");
	}
	
      if(FD_ISSET(sockid,&fdvec)){
            
	msglen = sizeof(msg);
	fromlen = sizeof(struct sockaddr_in);
	if((msglen = recvfrom(sockid,msg,msglen,0,(struct sockaddr*)&from, &fromlen))<0)
	  {
	    if(errno == ECONNREFUSED||errno == ENETUNREACH || errno == EHOSTUNREACH);
	    else
	      perror("recvfrom() failed in dsn_maker");
	  }

	if(msglen < 0)continue;

	ip = (struct iphdr *)msg;
	iphdrlen = ip->ihl <<2; /*Bytes */
	icp = (struct icmp*)(msg + iphdrlen); /* remove IP header */
	msglen -= iphdrlen; 
	
	if(debug >2)
	  fprintf(stderr,"Recvd message on rtdisc socket from %s \n",inet_ntoa(from.sin_addr));
	else
	  fprintf(stderr,".");

	if(cannotignore((char*)icp,&src,msglen) && (heard_no_adv || src == Myinfo.closeagentaddr))
	  {
	    heard_no_adv = FALSE;
	    p = (msg + iphdrlen + SIZE_ICMP_HDR + 
				       4*(icp->addr_entry_size)*(icp->addrnum));
	    msglen -= SIZE_ICMP_HDR +4*(icp->addr_entry_size)*(icp->addrnum);
	    /*Store only router discovery message */
	    memcpy(Dminfo.rtdismsg,p,msglen);
	    memcpy((char*)&Dminfo.from,(char*)&from,sizeof(struct sockaddr_in));
	  }
      }
      
    }

  /* Indicate in log that no adv is heard*/
  if(heard_no_adv)
    fprintf(stderr,"?");

  if(doit)return;

  if(!IsOurAddress(ipaddr)&& ipaddr != 0)
    {
      /* This indicates that MH interface addr is
	 changed. So go for POPUPACTION */
      
      Dminfo.action = POPUPACTION;
      Dminfo.coaddr = ipaddr;
      Dminfo.gw = gw;
      Dminfo.closeagentaddr = 0;
      strcpy(Dminfo.infname,dev);
      Dminfo.seqno = 0;
      Dminfo.lifetime = MAXLIFETIME;
      Dminfo.flags = 0; 
      /*
      bzero(Dminfo.rtdismsg,sizeof(Dminfo.rtdismsg));
      bzero(&(Dminfo.from),sizeof(struct sockaddr_in));
      */
      }

  if(heard_no_adv && Dminfo.action == POPUPACTION)
    {
      /* This indicates that MH has acquired new IP address
	 due to PPP or DHCP and no router discovery messages are
	 heard.
	 */
       
      doit =1;
    }

  else if(heard_no_adv == FALSE)
    { 
      urh = (struct youarehere*)Dminfo.rtdismsg;
      if(IsOurAgent(src))
	{
	  Dminfo.action = HOMEACTION;
	  Dminfo.closeagentaddr = src;
	  Dminfo.coaddr = Myinfo.homeaddr;
	  Dminfo.gw = gw;
	  strcpy(Dminfo.infname,dev);
	  Dminfo.seqno = urh->seqno;
	  Dminfo.lifetime = urh->lifetime;
	  Dminfo.flags = urh->flags;
	  doit = 1;
	}
      else /* Not at Home */
	{
	  Dminfo.action = FOREIGNACTION;
	  Dminfo.closeagentaddr = src;
	  Dminfo.coaddr = src;
	  Dminfo.gw =gw;
	  strcpy(Dminfo.infname,dev);
	  Dminfo.seqno = urh->seqno;
	  Dminfo.lifetime = urh->lifetime;
	  Dminfo.flags = urh->flags;
	  doit = 1;
	}
    }
}

void copy_new()
{
  Myinfo.coaddr = Dminfo.coaddr;
  Myinfo.closeagentaddr = Dminfo.closeagentaddr;
  Myinfo.gw = Dminfo.gw;
  strcpy(Myinfo.infname,Dminfo.infname);
  Myinfo.seqno = Dminfo.seqno;
  Myinfo.lifetime = Dminfo.lifetime;
  Myinfo.agentflags = Dminfo.flags;
}

doer()
{
  struct sockaddr_in from;
  char msg[1024];
  int len, fromlen;
  fd_set fdvec;
  struct timeval tv;

  if(doit)
    switch(Dminfo.action){
    case FOREIGNACTION :
      if(Dminfo.coaddr != Myinfo.coaddr || did_reboot(Dminfo.seqno,Myinfo.seqno))
	{
	  if(debug>1)
	    fprintf(stderr,"Doer processing FOREIGNACTION with Coaddr %lx\n",
		    Dminfo.coaddr);

	  /* Flush all ARP entries */
	  lowflshARP();
	  /* Down dummy (if present) */
	  lowifacedown("dummy");
	  /* Delete earlier default route */
	  lowrtset(0x00000000,Myinfo.infname,DELRT);
	  /* Delete route to home network if present */
	   lowrtnetset((Myinfo.homeagent & Myinfo.homenetmask),Myinfo.infname,0,DELRT);
	  /* Delete network route if earlier state was ASPOPUP */
	  if((Myinfo.status & 0x03)==ASPOPUP)
	    lowrtnetset((Myinfo.coaddr & Myinfo.foreignnetmask),Myinfo.infname,0,DELRT);
	  /* Delete route to existing default gateway*/
	  lowrtset(Myinfo.gw,Myinfo.infname,DELRT);
	  /* If it is INIT delete route to home agent anyway */
	  if((Myinfo.status & 0x03) == INIT)
	    lowrtset(Myinfo.homeagent,Myinfo.infname,DELRT);
	  /* Clear Myinfo*/
	  init(1);
	  /* Copy new info */ 
	  copy_new();
	  
	  /* Set new routes */
	  if(debug>2)fprintf(stderr,"Setting new routes...\n");
	  lowrtset(Myinfo.closeagentaddr,Myinfo.infname,ADDRT);
	  lowrtdefault(Myinfo.closeagentaddr);
	  Myinfo.timeleft = RETRYINTERVAL;
	  Myinfo.flags = 0x00|APREF; /* No Broadcast , FA will decapsulate, etc */
	  Myinfo.status = ATFOREIGN | WAITINGTOREGISTER | AWAITINGREPLY;
	  
	  sendRegisterMe(Myinfo.retries, Myinfo.flags, Myinfo.lifetime,
			 Myinfo.homeaddr, Myinfo.homeagent, Myinfo.coaddr);
	  if(debug >1)
	    fprintf(stderr,"Done with FOREIGNACTION\n");
			 
	}
      doit = 0;
      break;

    case HOMEACTION :
      if(Dminfo.coaddr != Myinfo.coaddr || did_reboot(Dminfo.seqno,Myinfo.seqno))
	{ 
	  char hwaddr[6];
	  if(debug>1){
	    fprintf(stderr,"Doer processing HOMEACTION\n");
	  }
	  
	  /* Flush all ARP entries */
	  lowflshARP();
	  /* Down dummy (if present) */
	  lowifacedown("dummy");
	  /* Delete earlier default route */
	  lowrtset(0x00000000,Myinfo.infname,DELRT); 
	  /* Delete network route if earlier state was ASPOPUP */
	  if((Myinfo.status & 0x03)==ASPOPUP)
	    lowrtnetset((Myinfo.coaddr & Myinfo.foreignnetmask),Myinfo.infname,0,DELRT);
	  /* Delete route to existing default gateway*/
	  lowrtset(Myinfo.gw,Myinfo.infname,DELRT);
	  /* Clear Myinfo*/
	  init(1);
	  /* Copy new info */
	  copy_new();
	  
	  /* Set new routes */
	  if(debug>2)fprintf(stderr,"Setting new routes...\n");
	  lowrtnetset((Myinfo.homeagent & Myinfo.homenetmask),Myinfo.infname,Myinfo.homenetmask,ADDRT);
	  lowrtdefault(Myinfo.closeagentaddr);
	  /* Send gratuitous ARP*/
	  lowhwaddrreq(Myinfo.infname,hwaddr); /* get hwaddr */
	  lowarpsend(Myinfo.infname,Myinfo.homeaddr,hwaddr,Myinfo.homeaddr);

	  Myinfo.timeleft =  RETRYINTERVAL;
	  Myinfo.lifetime = 0; /*Deregistration */
	  Myinfo.flags = 0x00|APREF;
	  Myinfo.status = ATHOME | WAITINGTODEREGISTER| AWAITINGREPLY;
	  sendRegisterMe(Myinfo.retries, Myinfo.flags, Myinfo.lifetime,
		     Myinfo.homeaddr, Myinfo.homeagent, Myinfo.coaddr);
	  if(debug >1)
	    fprintf(stderr,"Done with HOMEACTION\n");
	  
	}
      doit =0;
      break;
     
    case POPUPACTION:
      if(Dminfo.coaddr != Myinfo.coaddr)
	{
	  if(debug>1)
	    fprintf(stderr,"Doer processing POPUPACTION\n");
	  lowflshARP();
	  /* Make dummy down */
	  lowifacedown("dummy");
	  if((Myinfo.status & 0x03)==ASPOPUP)
	    lowrtnetset((Myinfo.coaddr & Myinfo.foreignnetmask),Myinfo.infname,0,DELRT);
	  /* Delete route to home network if present */
	   lowrtnetset((Myinfo.homeagent & Myinfo.homenetmask),Myinfo.infname,0,DELRT);
	  /* Delete route to existing default gateway*/
	  lowrtset(Myinfo.gw,Myinfo.infname,DELRT);
	  init(1);
	  /* Copy new info */ 
	  copy_new();
	  
	  /* Set new routes */
	  Myinfo.timeleft = RETRYINTERVAL;
	  Myinfo.flags = 0x20|APREF; /* MH will decapsulate */
	  lownetmaskreq(Myinfo.infname,&Myinfo.foreignnetmask);
	  Myinfo.status = ASPOPUP | WAITINGTOREGISTER| AWAITINGREPLY;
	  
	  sendRegisterMe(Myinfo.retries, Myinfo.flags, Myinfo.lifetime,
		     Myinfo.homeaddr, Myinfo.homeagent, Myinfo.coaddr);
	  if(debug >1)
	    fprintf(stderr,"Done with POPUPACTION\n");

	}
      doit =0;
      break;
      
    default:
      break;
    } 


  /* Check for any registration reply */

  FD_ZERO(&fdvec); FD_SET(Regreplysid, &fdvec); 
  tv.tv_sec = 0; tv.tv_usec = 0;

  while(( select(FD_SETSIZE, &fdvec, NULL, NULL, &tv)) < 0)  {
    if(errno == EINTR);
    else 
      perror("select() failed in Doer\n");
  }
     
  len = 1024; fromlen = sizeof(struct sockaddr_in);
  if (FD_ISSET(Regreplysid, &fdvec))  
    {
      if ((len = recvfrom(Regreplysid, msg, len, 0,
			  (struct sockaddr *) &from, &fromlen)) < 0)  
	{
	  perror("recvfrom() on RegisterMesid failed.\n");
	  if(errno == ECONNREFUSED || 
	     errno == ENETUNREACH || errno == EHOSTUNREACH);
	  else
	
	    {
	      cleanup(); exit(-1);
	    }
	};
      processRegreply(msg, len, &from);
    }

}/* End of Doer */

main(int argc, char **argv)  
{
  char *cmd;
  int c;
  extern char *optarg;
  extern int optind;
  unsigned char argsfound = 0;
    
  cmd = argv[0];
  while ((c = getopt(argc, argv, "a:m:g:")) != -1)  {
      switch ((char) c)  {
       case 'a':
	 argsfound |= 0x01;
	 if ((Myinfo.homeaddr = inet_addr(optarg)) == -1)  {
	    fprintf(stderr, "Bad address passed to -a.\n");
	    exit(-1);
	 };
	 break;
       case 'm':
	 argsfound |= 0x02;
	 if ((Myinfo.homenetmask = inet_addr(optarg)) == -1)  {
	    fprintf(stderr, "Bad netmask passed to -m.\n");
	    exit(-1);
	 };
	 break;
       case 'g':
	 argsfound |= 0x04;
	 if ((Myinfo.homeagent = inet_addr(optarg)) == -1)
	   {
	    fprintf(stderr, "Bad address passed to -g.\n");
	    exit(-1);
	 };
	 break;
       
      case '?':
	 usage(cmd);
	 exit(1);
	 break;
      }
   }

   if (argsfound != 0x07)  {
      usage(cmd);
      exit(1);
   }
     

   if (debug > 1)  {
    fprintf(stderr, "IPaddr: %lx, Mask: %lx, HomeAgent: %lx\n",
	      htonl(Myinfo.homeaddr), htonl(Myinfo.homenetmask),
	      htonl(Myinfo.homeagent));
   }

   init(0);
   sendroutersol(&routersolto);
   while (1)  
     { 
       doer();
       slp(0.5);
     }
}

void
usage(char *cmd)  {
   fprintf(stderr, 
   "Usage is: %s -a homeaddr -m homenetmask -g haaddr \n",
	   cmd);
}