zeek/src/PacketFilter.h
2011-08-04 15:21:18 -05:00

45 lines
1.2 KiB
C++

// Provides some very limited but fast packet filter mechanisms
#ifndef PACKETFILTER_H
#define PACKETFILTER_H
#include "IP.h"
#include "PrefixTable.h"
class PacketFilter {
public:
PacketFilter(bool arg_default) { default_match = arg_default; }
~PacketFilter() {}
// Drops all packets from a particular source (which may be given
// as an AddrVal or a SubnetVal) which hasn't any of TCP flags set
// (TH_*) with the given probability (from 0..MAX_PROB).
void AddSrc(addr_type src, uint32 tcp_flags, double probability);
void AddSrc(Val* src, uint32 tcp_flags, double probability);
void AddDst(addr_type src, uint32 tcp_flags, double probability);
void AddDst(Val* src, uint32 tcp_flags, double probability);
// Removes the filter entry for the given src/dst
// Returns false if filter doesn not exist.
bool RemoveSrc(addr_type src);
bool RemoveSrc(Val* dst);
bool RemoveDst(addr_type dst);
bool RemoveDst(Val* dst);
// Returns true if packet matches a drop filter
bool Match(const IP_Hdr* ip, int len, int caplen);
private:
struct Filter {
uint32 tcp_flags;
uint32 probability;
};
bool MatchFilter(const Filter& f, const IP_Hdr& ip, int len, int caplen);
bool default_match;
PrefixTable src_filter;
PrefixTable dst_filter;
};
#endif