checktcpheader.hh

COPE the first practical network coding scheme which is developped on click

#ifndef CLICK_CHECKTCPHEADER_HH
#define CLICK_CHECKTCPHEADER_HH
#include <click/element.hh>
#include <click/atomic.hh>
CLICK_DECLS

/*
=c

CheckTCPHeader([I<KEYWORDS>])

=s TCP, checking

checks TCP header on TCP/IP packets

=d

Expects TCP/IP packets as input. Checks that the TCP header length and
checksum fields are valid. Pushes invalid packets out on output 1, unless
output 1 was unused; if so, drops invalid packets.

Prints a message to the console the first time it encounters an incorrect
packet (but see VERBOSE below).

Keyword arguments are:

=over 5

=item VERBOSE

Boolean. If it is true, then a message will be printed for every erroneous
packet, rather than just the first. False by default.

=item DETAILS

Boolean. If it is true, then CheckTCPHeader will maintain detailed counts of
how many packets were dropped for each possible reason, accessible through the
C<drop_details> handler. False by default.

=back

=h drops read-only

Returns the number of incorrect packets CheckTCPHeader has seen.

=h drop_details read-only

Returns a text file showing how many erroneous packets CheckTCPHeader has
seen, subdivided by error. Only available if the DETAILS keyword argument was
true.

=a CheckIPHeader, CheckUDPHeader, CheckICMPHeader, MarkIPHeader */

class CheckTCPHeader : public Element { public:
  
  CheckTCPHeader();
  ~CheckTCPHeader();
  
  const char *class_name() const		{ return "CheckTCPHeader"; }
  const char *processing() const		{ return "a/ah"; }
  
  void notify_noutputs(int);
  int configure(Vector<String> &, ErrorHandler *);
  void add_handlers();

  Packet *simple_action(Packet *);
  /* inline Packet *smaction(Packet *);
     void push(int, Packet *p);
     Packet *pull(int); */

 private:
  
  bool _verbose : 1;
  atomic_uint32_t _drops;
  atomic_uint32_t *_reason_drops;

  enum Reason {
    NOT_TCP,
    BAD_LENGTH,
    BAD_CHECKSUM,
    NREASONS
  };
  static const char *reason_texts[NREASONS];
  
  Packet *drop(Reason, Packet *);
  static String read_handler(Element *, void *);
  
};

CLICK_ENDDECLS
#endif