zeek/src/PacketFilter.h
2020-01-02 12:05:49 -08:00

44 lines
1.2 KiB
C++

// Provides some very limited but fast packet filter mechanisms
#pragma once
#include "IP.h"
#include "PrefixTable.h"
class PacketFilter {
public:
explicit PacketFilter(bool 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(const IPAddr& src, uint32_t tcp_flags, double probability);
void AddSrc(Val* src, uint32_t tcp_flags, double probability);
void AddDst(const IPAddr& src, uint32_t tcp_flags, double probability);
void AddDst(Val* src, uint32_t tcp_flags, double probability);
// Removes the filter entry for the given src/dst
// Returns false if filter doesn not exist.
bool RemoveSrc(const IPAddr& src);
bool RemoveSrc(Val* dst);
bool RemoveDst(const IPAddr& 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_t tcp_flags;
uint32_t probability;
};
static void DeleteFilter(void* data);
bool MatchFilter(const Filter& f, const IP_Hdr& ip, int len, int caplen);
bool default_match;
PrefixTable src_filter;
PrefixTable dst_filter;
};