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252 lines
6.6 KiB
C++
252 lines
6.6 KiB
C++
#pragma once
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#include "zeek/zeek-config.h"
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#include <stdint.h>
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#include <sys/types.h> // for u_char
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#include <string>
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#if defined(__OpenBSD__)
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#include <net/bpf.h>
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typedef struct bpf_timeval pkt_timeval;
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#else
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typedef struct timeval pkt_timeval;
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#endif
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#include <pcap.h> // For DLT_ constants
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#include "zeek/NetVar.h" // For BifEnum::Tunnel
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#include "zeek/TunnelEncapsulation.h"
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#include "zeek/IP.h"
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namespace zeek {
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class ODesc;
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class Val;
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class RecordVal;
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template <class T> class IntrusivePtr;
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using ValPtr = IntrusivePtr<Val>;
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using RecordValPtr = IntrusivePtr<RecordVal>;
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/**
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* The Layer 3 type of a packet, as determined by the parsing code in Packet.
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* This enum is sized as an int32_t to make the Packet structure align
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* correctly.
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*/
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enum Layer3Proto : int32_t {
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L3_UNKNOWN = -1, /// Layer 3 type could not be determined.
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L3_IPV4 = 1, /// Layer 3 is IPv4.
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L3_IPV6 = 2, /// Layer 3 is IPv6.
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L3_ARP = 3, /// Layer 3 is ARP.
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};
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/**
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* A link-layer packet.
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*/
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class Packet {
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public:
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/**
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* Construct and initialize from packet data.
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*
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* @param link_type The link type in the form of a \c DLT_* constant.
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*
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* @param ts The timestamp associated with the packet.
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*
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* @param caplen The number of bytes valid in *data*.
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*
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* @param len The wire length of the packet, which must be more or
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* equal *caplen* (but can't be less).
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*
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* @param data A pointer to the raw packet data, starting with the
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* layer 2 header. The pointer must remain valid for the lifetime of
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* the Packet instance, unless *copy* is true.
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*
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* @param copy If true, the constructor will make an internal copy of
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* *data*, so that the caller can release its version.
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*
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* @param tag A textual tag to associate with the packet for
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* differentiating the input streams.
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*/
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Packet(int link_type, pkt_timeval *ts, uint32_t caplen,
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uint32_t len, const u_char *data, bool copy = false,
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std::string tag = "")
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{
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Init(link_type, ts, caplen, len, data, copy, tag);
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}
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/**
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* Default constructor. For internal use only.
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*/
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Packet()
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{
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pkt_timeval ts = {0, 0};
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Init(0, &ts, 0, 0, nullptr);
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}
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/**
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* Destructor.
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*/
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~Packet();
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/**
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* (Re-)initialize from packet data.
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*
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* @param link_type The link type in the form of a \c DLT_* constant.
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*
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* @param ts The timestamp associated with the packet.
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*
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* @param caplen The number of bytes valid in *data*.
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*
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* @param len The wire length of the packet, which must be more or
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* equal *caplen* (but can't be less).
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*
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* @param data A pointer to the raw packet data, starting with the
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* layer 2 header. The pointer must remain valid for the lifetime of
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* the Packet instance, unless *copy* is true.
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*
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* @param copy If true, the constructor will make an internal copy of
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* *data*, so that the caller can release its version.
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*
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* @param tag A textual tag to associate with the packet for
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* differentiating the input streams.
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*/
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void Init(int link_type, pkt_timeval *ts, uint32_t caplen,
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uint32_t len, const u_char *data, bool copy = false,
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std::string tag = "");
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/**
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* Returns a \c raw_pkt_hdr RecordVal, which includes layer 2 and
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* also everything in IP_Hdr (i.e., IP4/6 + TCP/UDP/ICMP).
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*/
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RecordValPtr ToRawPktHdrVal() const;
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/**
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* Maximal length of a layer 2 address.
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*/
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static const int L2_ADDR_LEN = 6;
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/**
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* Empty layer 2 address to be used as default value. For example, the
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* LinuxSLL packet analyzer doesn't have a destination address in the
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* header and thus sets it to this default address.
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*/
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static constexpr const u_char L2_EMPTY_ADDR[L2_ADDR_LEN] = { 0 };
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// These are passed in through the constructor.
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std::string tag; /// Used in serialization
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double time; /// Timestamp reconstituted as float
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pkt_timeval ts; /// Capture timestamp
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const u_char* data = nullptr; /// Packet data.
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uint32_t len; /// Actual length on wire
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uint32_t cap_len; /// Captured packet length
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uint32_t link_type; /// pcap link_type (DLT_EN10MB, DLT_RAW, etc)
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/**
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* Layer 3 protocol identified (if any).
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*/
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Layer3Proto l3_proto;
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/**
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* If layer 2 is Ethernet, innermost ethertype field.
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*/
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uint32_t eth_type;
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/**
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* Layer 2 source address.
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*/
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const u_char* l2_src = nullptr;
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/**
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* Layer 2 destination address.
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*/
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const u_char* l2_dst = nullptr;
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/**
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* (Outermost) VLAN tag if any, else 0.
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*/
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uint32_t vlan;
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/**
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* (Innermost) VLAN tag if any, else 0.
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*/
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uint32_t inner_vlan;
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/**
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* Indicates whether the layer 2 checksum was validated by the
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* hardware/kernel before being received by zeek.
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*/
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bool l2_checksummed;
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/**
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* Indicates whether the layer 3 checksum was validated by the
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* hardware/kernel before being received by zeek.
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*/
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bool l3_checksummed;
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/**
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* Indicates whether this packet should be recorded.
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*/
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mutable bool dump_packet;
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/**
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* Indicates the amount of data to be dumped. If only a header is needed,
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* set this to the size of the header. Setting it to zero will dump the
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* entire packet.
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*/
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mutable int dump_size = 0;
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// These are fields passed between various packet analyzers. They're best
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// stored with the packet so they stay available as the packet is passed
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// around.
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/**
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* The stack of encapsulations this packet belongs to, if any. This is
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* used by the tunnel analyzers to keep track of the encapsulations as
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* processing occurs.
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*/
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std::shared_ptr<EncapsulationStack> encap = nullptr;
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/**
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* The IP header for this packet. This is filled in by the IP analyzer
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* during processing if the packet contains an IP header.
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*/
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std::unique_ptr<IP_Hdr> ip_hdr = nullptr;
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/**
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* The protocol of the packet. This is used by the tunnel analyzers to
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* pass outer protocol from one level to the next.
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*/
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int proto = -1;
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/**
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* If the packet contains a tunnel, this field will be filled in with
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* the type of tunnel. It is used to pass the tunnel type between the
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* packet analyzers during analysis.
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*/
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BifEnum::Tunnel::Type tunnel_type = BifEnum::Tunnel::IP;
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/**
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* If the packet contains a GRE tunnel, this field will contain the
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* GRE version. It is used to pass this information from the GRE
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* analyzer to the IPTunnel analyzer.
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*/
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int gre_version = -1;
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/**
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* If the packet contains a GRE tunnel, this field will contain the
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* GRE link type. It is used to pass this information from the GRE
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* analyzer to the IPTunnel analyzer.
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*/
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int gre_link_type = DLT_RAW;
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private:
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// Renders an MAC address into its ASCII representation.
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ValPtr FmtEUI48(const u_char* mac) const;
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// True if we need to delete associated packet memory upon
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// destruction.
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bool copy;
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};
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} // namespace zeek
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