zeek/src/packet_analysis/protocol/ip/IP.h

59 lines
2.1 KiB
C++

// See the file "COPYING" in the main distribution directory for copyright.
#pragma once
#include "zeek/packet_analysis/Analyzer.h"
#include "zeek/packet_analysis/Component.h"
#include "zeek/Frag.h"
namespace zeek::detail { class Discarder; }
namespace zeek::packet_analysis::IP {
class IPAnalyzer : public Analyzer {
public:
IPAnalyzer();
~IPAnalyzer() override;
bool AnalyzePacket(size_t len, const uint8_t* data, Packet* packet) override;
static zeek::packet_analysis::AnalyzerPtr Instantiate()
{
return std::make_shared<IPAnalyzer>();
}
private:
// Returns a reassembled packet, or nil if there are still
// some missing fragments.
zeek::detail::FragReassembler* NextFragment(double t, const IP_Hdr* ip,
const u_char* pkt);
zeek::detail::Discarder* discarder = nullptr;
};
/**
* Returns a wrapper IP_Hdr object if \a pkt appears to be a valid IPv4
* or IPv6 header based on whether it's long enough to contain such a header,
* if version given in the header matches the proto argument, and also checks
* that the payload length field of that header matches the actual
* length of \a pkt given by \a caplen.
*
* @param caplen The length of \a pkt in bytes.
* @param pkt The inner IP packet data.
* @param proto Either IPPROTO_IPV6 or IPPROTO_IPV4 to indicate which IP
* protocol \a pkt corresponds to.
* @param inner The inner IP packet wrapper pointer to be allocated/assigned
* if \a pkt looks like a valid IP packet or at least long enough
* to hold an IP header.
* @return 0 If the inner IP packet appeared valid, else -1 if \a caplen
* is greater than the supposed IP packet's payload length field, -2
* if the version of the inner header does not match proto or
* 1 if \a caplen is less than the supposed packet's payload length.
* In the -1 case, \a inner may still be non-null if \a caplen was
* long enough to be an IP header, and \a inner is always non-null
* for other return values.
*/
int ParsePacket(int caplen, const u_char* const pkt, int proto,
std::unique_ptr<IP_Hdr>& inner);
}