aggregateipflows.cc

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{
    if (_gc_sec) {
	reap_map(_tcp_map, _tcp_timeout, _tcp_done_timeout);
	reap_map(_udp_map, _udp_timeout, _udp_timeout);
    }
    _gc_sec = _active_sec + _gc_interval;
}

const click_ip *
AggregateIPFlows::icmp_encapsulated_header(const Packet *p)
{
    const click_icmp *icmph = p->icmp_header();
    if (p->has_transport_header()
	&& (icmph->icmp_type == ICMP_UNREACH
	    || icmph->icmp_type == ICMP_TIMXCEED
	    || icmph->icmp_type == ICMP_PARAMPROB
	    || icmph->icmp_type == ICMP_SOURCEQUENCH
	    || icmph->icmp_type == ICMP_REDIRECT)) {
	const click_ip *embedded_iph = reinterpret_cast<const click_ip *>(icmph + 1);
	unsigned embedded_hlen = embedded_iph->ip_hl << 2;
	if ((unsigned)p->transport_length() >= sizeof(click_icmp) + embedded_hlen
	    && embedded_hlen >= sizeof(click_ip))
	    return embedded_iph;
    }
    return 0;
}

int
AggregateIPFlows::relevant_timeout(const FlowInfo *f, const Map &m) const
{
    if (&m == &_udp_map)
	return _udp_timeout;
    else if (f->_flow_over == 3)
	return _tcp_done_timeout;
    else
	return _tcp_timeout;
}

// XXX timing when fragments are merged back in?

AggregateIPFlows::FlowInfo *
AggregateIPFlows::find_flow_info(Map &m, HostPairInfo *hpinfo, uint32_t ports, bool flipped, const Packet *p)
{
    FlowInfo **pprev = &hpinfo->_flows;
    for (FlowInfo *finfo = *pprev; finfo; pprev = &finfo->_next, finfo = finfo->_next)
	if (finfo->_ports == ports) {
	    // if this flow is actually dead (but has not yet been garbage
	    // collected), then kill it for consistent semantics
	    int age = p->timestamp_anno().sec() - finfo->_last_timestamp.sec();
	    // 4.Feb.2004 - Also start a new flow if the old flow closed off,
	    // and we have a SYN.
	    if ((age > _smallest_timeout
		 && age > relevant_timeout(finfo, m))
		|| (finfo->_flow_over == 3
		    && p->ip_header()->ip_p == IP_PROTO_TCP
		    && (p->tcp_header()->th_flags & TH_SYN))) {
		// old aggregate has died
		notify(finfo->aggregate(), AggregateListener::DELETE_AGG, 0);
		const click_ip *iph = good_ip_header(p);
		HostPair hp(iph->ip_src.s_addr, iph->ip_dst.s_addr);
		delete_flowinfo(hp, finfo, false);

		// make a new aggregate
		finfo->_aggregate = _next;
		_next++;
		finfo->_reverse = flipped;
		finfo->_flow_over = 0;
#if CLICK_USERLEVEL
		if (stats())
		    stat_new_flow_hook(p, finfo);
#endif
		notify(finfo->aggregate(), AggregateListener::NEW_AGG, p);
	    }

	    // otherwise, move to the front of the list and return
	    *pprev = finfo->_next;
	    finfo->_next = hpinfo->_flows;
	    hpinfo->_flows = finfo;
	    return finfo;
	}

    // make and install new FlowInfo pair
    FlowInfo *finfo;
#if CLICK_USERLEVEL
    if (stats()) {
	finfo = new StatFlowInfo(ports, hpinfo->_flows, _next);
	stat_new_flow_hook(p, finfo);
    } else
#endif
	finfo = new FlowInfo(ports, hpinfo->_flows, _next);

    finfo->_reverse = flipped;
    hpinfo->_flows = finfo;
    _next++;
    notify(finfo->aggregate(), AggregateListener::NEW_AGG, p);
    return finfo;
}

void
AggregateIPFlows::emit_fragment_head(HostPairInfo *hpinfo)
{
    Packet *head = hpinfo->_fragment_head;
    hpinfo->_fragment_head = head->next();

    const click_ip *iph = good_ip_header(head);
    // XXX multiple linear traversals of entire fragment list!
    // want a faster method that takes up little memory?

    if (AGGREGATE_ANNO(head)) {
	for (Packet *p = hpinfo->_fragment_head; p; p = p->next())
	    if (good_ip_header(p)->ip_id == iph->ip_id) {
		SET_AGGREGATE_ANNO(p, AGGREGATE_ANNO(head));
		SET_PAINT_ANNO(p, PAINT_ANNO(head));
	    }
    } else {
	for (Packet *p = hpinfo->_fragment_head; p; p = p->next())
	    if (good_ip_header(p)->ip_id == iph->ip_id
		&& AGGREGATE_ANNO(p)) {
		SET_AGGREGATE_ANNO(head, AGGREGATE_ANNO(p));
		SET_PAINT_ANNO(head, PAINT_ANNO(p));
		goto find_flowinfo;
	    }
	head->kill();
	return;
    }

  find_flowinfo:
    // find the packet's FlowInfo
    FlowInfo *finfo, **pprev = &hpinfo->_flows;
    for (finfo = *pprev; finfo; pprev = &finfo->_next, finfo = *pprev)
	if (finfo->_aggregate == AGGREGATE_ANNO(head)) {
	    *pprev = finfo->_next;
	    finfo->_next = hpinfo->_flows;
	    hpinfo->_flows = finfo;
	    break;
	}

    assert(finfo);
    packet_emit_hook(head, iph, finfo);
    output(0).push(head);
}

int
AggregateIPFlows::handle_fragment(Packet *p, HostPairInfo *hpinfo)
{
    if (hpinfo->_fragment_head)
	hpinfo->_fragment_tail->set_next(p);
    else
	hpinfo->_fragment_head = p;
    hpinfo->_fragment_tail = p;
    p->set_next(0);
    _active_sec = p->timestamp_anno().sec();

    // get rid of old fragments
    int frag_timeout = _active_sec - _fragment_timeout;
    Packet *head;
    while ((head = hpinfo->_fragment_head)
	   && (head->timestamp_anno().sec() < frag_timeout
	       || !IP_ISFRAG(good_ip_header(head))))
	emit_fragment_head(hpinfo);

    return ACT_NONE;
}

int
AggregateIPFlows::handle_packet(Packet *p)
{
    const click_ip *iph = p->ip_header();
    int paint = 0;

    // assign timestamp if no timestamp given
    if (!p->timestamp_anno()) {
	if (!_timestamp_warning) {
	    click_chatter("%{element}: warning: packet received without timestamp", this);
	    _timestamp_warning = true;
	}
	p->timestamp_anno().set_now();
    }

    // extract encapsulated ICMP header if appropriate
    if (p->has_network_header() && iph->ip_p == IP_PROTO_ICMP
	&& IP_FIRSTFRAG(iph) && _handle_icmp_errors) {
	iph = icmp_encapsulated_header(p);
	paint = 2;
    }

    // return if not a proper TCP/UDP packet
    if (!p->has_network_header()
	|| (iph->ip_p != IP_PROTO_TCP && iph->ip_p != IP_PROTO_UDP)
	|| (iph->ip_src.s_addr == 0 && iph->ip_dst.s_addr == 0))
	return ACT_DROP;

    // find relevant HostPairInfo
    Map &m = (iph->ip_p == IP_PROTO_TCP ? _tcp_map : _udp_map);
    HostPair hosts(iph->ip_src.s_addr, iph->ip_dst.s_addr);
    if (hosts.a != iph->ip_src.s_addr)
	paint ^= 1;
    HostPairInfo *hpinfo = &m[hosts];

    // find relevant FlowInfo, if any
    FlowInfo *finfo;
    if (IP_FIRSTFRAG(iph)) {
	const uint8_t *udp_ptr = reinterpret_cast<const uint8_t *>(iph) + (iph->ip_hl << 2);
	if (udp_ptr + 4 > p->end_data())
	    // packet not big enough
	    return ACT_DROP;

	uint32_t ports = *reinterpret_cast<const uint32_t *>(udp_ptr);
	// 1.Jan.08: handle connections where IP addresses are the same (John
	// Russell Lane)
	if (hosts.a == hosts.b && ports_reverse_order(ports))
	    paint ^= 1;
	if (paint & 1)
	    ports = flip_ports(ports);

	finfo = find_flow_info(m, hpinfo, ports, paint & 1, p);
	if (!finfo) {
	    click_chatter("out of memory!");
	    return ACT_DROP;
	}
	if (finfo->reverse())
	    paint ^= 1;

	// set aggregate annotations
	SET_AGGREGATE_ANNO(p, finfo->aggregate());
	SET_PAINT_ANNO(p, paint);
    } else {
	finfo = 0;
	SET_AGGREGATE_ANNO(p, 0);
	SET_PAINT_ANNO(p, paint);
    }

    // check for fragment
    if ((_fragments && IP_ISFRAG(iph)) || hpinfo->_fragment_head)
	return handle_fragment(p, hpinfo);
    else if (!finfo)
	return ACT_DROP;

    // packet emit hook
    _active_sec = p->timestamp_anno().sec();
    packet_emit_hook(p, iph, finfo);

    return ACT_EMIT;
}

void
AggregateIPFlows::push(int, Packet *p)
{
    int action = handle_packet(p);

    // GC if necessary
    if (_active_sec >= _gc_sec)
	reap();

    if (action == ACT_EMIT)
	output(0).push(p);
    else if (action == ACT_DROP)
	checked_output_push(1, p);
}

Packet *
AggregateIPFlows::pull(int)
{
    Packet *p = input(0).pull();
    int action = (p ? handle_packet(p) : ACT_NONE);

    // GC if necessary
    if (_active_sec >= _gc_sec)
	reap();

    if (action == ACT_EMIT)
	return p;
    else if (action == ACT_DROP)
	checked_output_push(1, p);
    return 0;
}

enum { H_CLEAR };

int
AggregateIPFlows::write_handler(const String &, Element *e, void *thunk, ErrorHandler *)
{
    AggregateIPFlows *af = static_cast<AggregateIPFlows *>(e);
    switch ((intptr_t)thunk) {
      case H_CLEAR: {
	  int active_sec = af->_active_sec, gc_sec = af->_gc_sec;
	  af->_active_sec = af->_gc_sec = 0x7FFFFFFF;
	  af->reap();
	  af->_active_sec = active_sec, af->_gc_sec = gc_sec;
	  return 0;
      }
      default:
	return -1;
    }
}

void
AggregateIPFlows::add_handlers()
{
    add_write_handler("clear", write_handler, (void *)H_CLEAR);
}

ELEMENT_REQUIRES(AggregateNotifier)
EXPORT_ELEMENT(AggregateIPFlows)
CLICK_ENDDECLS