/* * checkip6header.{cc,hh} -- element checks IP6 header for correctness * (lengths, source addresses) * Robert Morris , Peilei Fan * * Copyright (c) 1999-2000 Massachusetts Institute of Technology * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, subject to the conditions * listed in the Click LICENSE file. These conditions include: you must * preserve this copyright notice, and you cannot mention the copyright * holders in advertising related to the Software without their permission. * The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This * notice is a summary of the Click LICENSE file; the license in that file is * legally binding. */#include <click/config.h>#include "checkip6header.hh"#include <clicknet/ip6.h>#include <click/ip6address.hh>#include <click/glue.hh>#include <click/confparse.hh>#include <click/error.hh>#include <click/standard/alignmentinfo.hh>#ifdef CLICK_LINUXMODULE# include <net/checksum.h>#endifCLICK_DECLSCheckIP6Header::CheckIP6Header()  : _bad_src(0), _drops(0){}CheckIP6Header::~CheckIP6Header(){  delete[] _bad_src;}intCheckIP6Header::configure(Vector<String> &conf, ErrorHandler *errh){  if (conf.size() > 1)    return errh->error("too many arguments to `CheckIP6Header([ADDRS])'"); Vector<String> ips; // ips.push_back("0::0"); // this address is only bad if we are a router ips.push_back("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff"); // bad IP6 address  if (conf.size()) {    Vector<String> words;    cp_spacevec(conf[0], words);    IP6Address a;    for (int j = 0; j < words.size(); j++) {      if (!cp_ip6_address(words[j], (unsigned char *)&a)) {	return errh->error("expects IP6ADDRESS -a ");      }      for (int j = 0; j < ips.size(); j++) {	IP6Address b = IP6Address(ips[j]);	if (b == a)	  goto repeat;      }      ips.push_back(a.s());     repeat: ;    }  }  _n_bad_src = ips.size();  _bad_src = new IP6Address [_n_bad_src];  for (int i = 0; i<_n_bad_src; i++) {    _bad_src[i]= IP6Address(ips[i]);  }  return 0;}voidCheckIP6Header::drop_it(Packet *p){  if (_drops == 0)    click_chatter("IP6 header check failed");  _drops++;  if (noutputs() == 2)    output(1).push(p);  else    p->kill();}Packet *CheckIP6Header::simple_action(Packet *p){  const click_ip6 *ip = reinterpret_cast <const click_ip6 *>( p->data());  struct IP6Address src;  // check if the packet is smaller than ip6 header  if(p->length() < sizeof(click_ip6))    goto bad; // check version  if(ip->ip6_v != 6)    goto bad;  // check if the PayloadLength field is valid   if(ntohs(ip->ip6_plen) > (p->length()-40))     goto bad;  /*   * discard illegal source addresses.   * Configuration string should have listed all subnet   * broadcast addresses known to this router.   */   src=ip->ip6_src;   for(int i = 0; i < _n_bad_src; i++) {     if(src == _bad_src[i])       goto bad;   }  /*   * discard illegal destinations.   * We will do this in the IP6 routing table.   *   *   */  p->set_ip6_header(ip);  // shorten packet according to IP6 payload length field  if(ntohs(ip->ip6_plen) < (p->length()-40))    p->take(p->length() - 40 - ip->ip6_plen);  return(p); bad:  drop_it(p);  return 0;}static StringCheckIP6Header_read_drops(Element *xf, void *){  CheckIP6Header *f = (CheckIP6Header *)xf;  return String(f->drops());}voidCheckIP6Header::add_handlers(){  add_read_handler("drops", CheckIP6Header_read_drops, 0);}CLICK_ENDDECLSEXPORT_ELEMENT(CheckIP6Header)