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109 lines
3.4 KiB
C++
109 lines
3.4 KiB
C++
// See the file "COPYING" in the main distribution directory for copyright.
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#include "zeek/PacketFilter.h"
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#include "zeek/IP.h"
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namespace zeek::detail {
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void PacketFilter::DeleteFilter(void* data) {
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auto f = static_cast<Filter*>(data);
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delete f;
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}
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PacketFilter::PacketFilter(bool arg_default) {
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default_match = arg_default;
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src_filter.SetDeleteFunction(PacketFilter::DeleteFilter);
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dst_filter.SetDeleteFunction(PacketFilter::DeleteFilter);
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}
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void PacketFilter::AddSrc(const IPAddr& src, uint32_t tcp_flags, double probability) {
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Filter* f = new Filter;
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f->tcp_flags = tcp_flags;
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f->probability = probability * static_cast<double>(util::detail::max_random());
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auto prev = static_cast<Filter*>(src_filter.Insert(src, 128, f));
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delete prev;
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}
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void PacketFilter::AddSrc(Val* src, uint32_t tcp_flags, double probability) {
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Filter* f = new Filter;
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f->tcp_flags = tcp_flags;
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f->probability = probability * static_cast<double>(util::detail::max_random());
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auto prev = static_cast<Filter*>(src_filter.Insert(src, f));
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delete prev;
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}
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void PacketFilter::AddDst(const IPAddr& dst, uint32_t tcp_flags, double probability) {
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Filter* f = new Filter;
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f->tcp_flags = tcp_flags;
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f->probability = probability * static_cast<double>(util::detail::max_random());
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auto prev = static_cast<Filter*>(dst_filter.Insert(dst, 128, f));
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delete prev;
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}
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void PacketFilter::AddDst(Val* dst, uint32_t tcp_flags, double probability) {
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Filter* f = new Filter;
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f->tcp_flags = tcp_flags;
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f->probability = probability * static_cast<double>(util::detail::max_random());
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auto prev = static_cast<Filter*>(dst_filter.Insert(dst, f));
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delete prev;
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}
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bool PacketFilter::RemoveSrc(const IPAddr& src) {
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auto f = static_cast<Filter*>(src_filter.Remove(src, 128));
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delete f;
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return f != nullptr;
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}
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bool PacketFilter::RemoveSrc(Val* src) {
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auto f = static_cast<Filter*>(src_filter.Remove(src));
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delete f;
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return f != nullptr;
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}
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bool PacketFilter::RemoveDst(const IPAddr& dst) {
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auto f = static_cast<Filter*>(dst_filter.Remove(dst, 128));
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delete f;
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return f != nullptr;
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}
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bool PacketFilter::RemoveDst(Val* dst) {
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auto f = static_cast<Filter*>(dst_filter.Remove(dst));
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delete f;
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return f != nullptr;
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}
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bool PacketFilter::Match(const std::shared_ptr<IP_Hdr>& ip, int len, int caplen) {
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Filter* f = (Filter*)src_filter.Lookup(ip->SrcAddr(), 128);
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if ( f )
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return MatchFilter(*f, *ip, len, caplen);
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f = (Filter*)dst_filter.Lookup(ip->DstAddr(), 128);
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if ( f )
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return MatchFilter(*f, *ip, len, caplen);
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return default_match;
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}
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bool PacketFilter::MatchFilter(const Filter& f, const IP_Hdr& ip, int len, int caplen) {
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if ( ip.NextProto() == IPPROTO_TCP && f.tcp_flags ) {
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// Caution! The packet sanity checks have not been performed yet
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int ip_hdr_len = ip.HdrLen();
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len -= ip_hdr_len; // remove IP header
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caplen -= ip_hdr_len;
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if ( (unsigned int)len < sizeof(struct tcphdr) || (unsigned int)caplen < sizeof(struct tcphdr) )
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// Packet too short, will be dropped anyway.
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return false;
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const struct tcphdr* tp = (const struct tcphdr*)ip.Payload();
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if ( tp->th_flags & f.tcp_flags )
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// At least one of the flags is set, so don't drop
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return false;
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}
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return util::detail::random_number() < f.probability;
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}
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} // namespace zeek::detail
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