zeek/src/TunnelEncapsulation.h
Johanna Amann 36741c2fbf Reformat
2023-11-06 09:42:46 +00:00

243 lines
7.6 KiB
C++

// See the file "COPYING" in the main distribution directory for copyright.
#pragma once
#include "zeek/zeek-config.h"
#include <vector>
#include "zeek/ID.h"
#include "zeek/IP.h"
#include "zeek/IPAddr.h"
#include "zeek/NetVar.h"
#include "zeek/UID.h"
namespace zeek {
class Connection;
/**
* Represents various types of tunnel "connections", that is, a pair of
* endpoints whose communication encapsulates inner IP packets. This could
* mean IP packets nested inside IP packets or IP packets nested inside a
* transport layer protocol. EncapsulatingConn's are assigned a UID, which can
* be shared with Connection's in the case the tunnel uses a transport-layer.
*/
class EncapsulatingConn {
public:
/**
* Default tunnel connection constructor.
*/
EncapsulatingConn() : src_port(0), dst_port(0), proto(TRANSPORT_UNKNOWN), type(BifEnum::Tunnel::NONE), uid() {}
/**
* Construct an IP tunnel "connection" with its own UID.
* The assignment of "source" and "destination" addresses here can be
* arbitrary, comparison between EncapsulatingConn objects will treat IP
* tunnels as equivalent as long as the same two endpoints are involved.
*
* @param s The tunnel source address, likely taken from an IP header.
* @param d The tunnel destination address, likely taken from an IP header.
* @param t The type of IP tunnel.
*/
EncapsulatingConn(const IPAddr& s, const IPAddr& d, BifEnum::Tunnel::Type t = BifEnum::Tunnel::IP)
: src_addr(s),
dst_addr(d),
src_port(0),
dst_port(0),
proto(TRANSPORT_UNKNOWN),
type(t),
uid(UID(detail::bits_per_uid)) {}
/**
* Construct a tunnel connection using information from an already existing
* transport-layer-aware connection object.
*
* @param c The connection from which endpoint information can be extracted.
* If it already has a UID associated with it, that gets inherited,
* otherwise a new UID is created for this tunnel and \a c.
* @param t The type of tunneling that is occurring over the connection.
*/
EncapsulatingConn(Connection* c, BifEnum::Tunnel::Type t);
/**
* Copy constructor.
*/
EncapsulatingConn(const EncapsulatingConn& other)
: ip_hdr(other.ip_hdr),
src_addr(other.src_addr),
dst_addr(other.dst_addr),
src_port(other.src_port),
dst_port(other.dst_port),
proto(other.proto),
type(other.type),
uid(other.uid) {}
/**
* Destructor.
*/
~EncapsulatingConn() {}
EncapsulatingConn& operator=(const EncapsulatingConn& other) {
if ( this != &other ) {
src_addr = other.src_addr;
dst_addr = other.dst_addr;
src_port = other.src_port;
dst_port = other.dst_port;
proto = other.proto;
type = other.type;
uid = other.uid;
ip_hdr = other.ip_hdr;
}
return *this;
}
BifEnum::Tunnel::Type Type() const { return type; }
/**
* Returns record value of type "EncapsulatingConn" representing the tunnel.
*/
RecordValPtr ToVal() const;
friend bool operator==(const EncapsulatingConn& ec1, const EncapsulatingConn& ec2) {
if ( ec1.type != ec2.type )
return false;
if ( ec1.type == BifEnum::Tunnel::IP || ec1.type == BifEnum::Tunnel::GRE )
// Reversing endpoints is still same tunnel.
return ec1.uid == ec2.uid && ec1.proto == ec2.proto &&
((ec1.src_addr == ec2.src_addr && ec1.dst_addr == ec2.dst_addr) ||
(ec1.src_addr == ec2.dst_addr && ec1.dst_addr == ec2.src_addr));
if ( ec1.type == BifEnum::Tunnel::VXLAN )
// Reversing endpoints is still same tunnel, destination port is
// always the same.
return ec1.dst_port == ec2.dst_port && ec1.uid == ec2.uid && ec1.proto == ec2.proto &&
((ec1.src_addr == ec2.src_addr && ec1.dst_addr == ec2.dst_addr) ||
(ec1.src_addr == ec2.dst_addr && ec1.dst_addr == ec2.src_addr));
return ec1.src_addr == ec2.src_addr && ec1.dst_addr == ec2.dst_addr && ec1.src_port == ec2.src_port &&
ec1.dst_port == ec2.dst_port && ec1.uid == ec2.uid && ec1.proto == ec2.proto;
}
friend bool operator!=(const EncapsulatingConn& ec1, const EncapsulatingConn& ec2) { return ! (ec1 == ec2); }
// TODO: temporarily public
std::shared_ptr<IP_Hdr> ip_hdr;
protected:
IPAddr src_addr;
IPAddr dst_addr;
uint16_t src_port;
uint16_t dst_port;
TransportProto proto;
BifEnum::Tunnel::Type type;
UID uid;
};
/**
* Abstracts an arbitrary amount of nested tunneling.
*/
class EncapsulationStack {
public:
EncapsulationStack() : conns(nullptr) {}
EncapsulationStack(const EncapsulationStack& other) {
if ( other.conns )
conns = new std::vector<EncapsulatingConn>(*(other.conns));
else
conns = nullptr;
}
EncapsulationStack& operator=(const EncapsulationStack& other) {
if ( this == &other )
return *this;
delete conns;
if ( other.conns )
conns = new std::vector<EncapsulatingConn>(*(other.conns));
else
conns = nullptr;
return *this;
}
~EncapsulationStack() { delete conns; }
/**
* Add a new inner-most tunnel to the EncapsulationStack.
*
* @param c The new inner-most tunnel to append to the tunnel chain.
*/
void Add(const EncapsulatingConn& c) {
if ( ! conns )
conns = new std::vector<EncapsulatingConn>();
conns->push_back(c);
}
/**
* Return how many nested tunnels are involved in a encapsulation, zero
* meaning no tunnels are present.
*/
size_t Depth() const { return conns ? conns->size() : 0; }
/**
* Return the tunnel type of the inner-most tunnel.
*/
BifEnum::Tunnel::Type LastType() const {
return conns ? (*conns)[conns->size() - 1].Type() : BifEnum::Tunnel::NONE;
}
/**
* Get the value of type "EncapsulatingConnVector" represented by the
* entire encapsulation chain.
*/
VectorValPtr ToVal() const {
auto vv = make_intrusive<VectorVal>(id::find_type<VectorType>("EncapsulatingConnVector"));
if ( conns ) {
for ( size_t i = 0; i < conns->size(); ++i )
vv->Assign(i, (*conns)[i].ToVal());
}
return vv;
}
friend bool operator==(const EncapsulationStack& e1, const EncapsulationStack& e2);
friend bool operator!=(const EncapsulationStack& e1, const EncapsulationStack& e2) { return ! (e1 == e2); }
/**
* Returns a pointer the last element in the stack. Returns a nullptr
* if the stack is empty or hasn't been initialized yet.
*/
EncapsulatingConn* Last() { return Depth() > 0 ? &(conns->back()) : nullptr; }
/**
* Returns an EncapsulatingConn from the requested index in the stack.
*
* @param index An index to look up. Note this is one-indexed, since it's generally
* looked up using a value from Depth().
* @return The corresponding EncapsulatingConn, or a nullptr if the requested index is
* out of range.
*/
EncapsulatingConn* At(size_t index) {
if ( index > 0 && index <= Depth() )
return &(conns->at(index - 1));
return nullptr;
}
/**
* Pops the last element off the encapsulation stack.
*/
void Pop();
protected:
std::vector<EncapsulatingConn>* conns;
};
} // namespace zeek