lokinet/llarp/link/utp_internal.hpp

358 lines
8.8 KiB
C++

#ifndef LLARP_LINK_UTP_INTERNAL_HPP
#define LLARP_LINK_UTP_INTERNAL_HPP
#include <constants/link_layer.hpp>
#include <crypto/types.hpp>
#include <link/utp.hpp>
#include <util/aligned.hpp>
#include <utp.h>
#include <tuple>
#include <deque>
namespace llarp
{
struct Crypto;
namespace utp
{
/// size of keyed hash
constexpr size_t FragmentHashSize = 32;
/// size of outer nonce
constexpr size_t FragmentNonceSize = 32;
/// size of outer overhead
constexpr size_t FragmentOverheadSize =
FragmentHashSize + FragmentNonceSize;
/// max fragment payload size
constexpr size_t FragmentBodyPayloadSize = 1024;
/// size of inner nonce
constexpr size_t FragmentBodyNonceSize = 24;
/// size of fragment body overhead
constexpr size_t FragmentBodyOverhead = FragmentBodyNonceSize
+ sizeof(uint32) + sizeof(uint16_t) + sizeof(uint16_t);
/// size of fragment body
constexpr size_t FragmentBodySize =
FragmentBodyOverhead + FragmentBodyPayloadSize;
/// size of fragment
constexpr size_t FragmentBufferSize =
FragmentOverheadSize + FragmentBodySize;
static_assert(FragmentBufferSize == 1120,
"Fragement Buffer Size is not 1120");
/// buffer for a single utp fragment
using FragmentBuffer = llarp::AlignedBuffer< FragmentBufferSize >;
/// maximum size for send queue for a session before we drop
constexpr size_t MaxSendQueueSize = 1024;
/// buffer for a link layer message
using MessageBuffer = llarp::AlignedBuffer< MAX_LINK_MSG_SIZE >;
struct LinkLayer;
/// pending inbound message being received
struct InboundMessage
{
/// timestamp of last activity
llarp_time_t lastActive;
/// the underlying message buffer
MessageBuffer _msg;
/// for accessing message buffer
llarp_buffer_t buffer;
InboundMessage() : lastActive(0), _msg(), buffer(_msg.as_buffer())
{
}
bool
operator==(const InboundMessage& other) const
{
return buffer.base == other.buffer.base;
}
/// return true if this inbound message can be removed due to expiration
bool
IsExpired(llarp_time_t now) const;
/// append data at ptr of size sz bytes to message buffer
/// increment current position
/// return false if we don't have enough room
/// return true on success
bool
AppendData(const byte_t* ptr, uint16_t sz);
};
struct Session final : public ILinkSession
{
/// remote router's rc
RouterContact remoteRC;
/// underlying socket
utp_socket* sock;
/// link layer parent
LinkLayer* parent;
/// did we get a LIM from the remote yet?
bool gotLIM;
/// remote router's transport pubkey
PubKey remoteTransportPubKey;
/// remote router's transport ip
Addr remoteAddr;
/// rx session key
SharedSecret rxKey;
/// tx session key
SharedSecret txKey;
/// timestamp last active
llarp_time_t lastActive;
/// session timeout (30s)
const static llarp_time_t sessionTimeout = 30 * 1000;
/// send queue for utp
std::deque< utp_iovec > vecq;
/// tx fragment queue
std::deque< FragmentBuffer > sendq;
/// current rx fragment buffer
FragmentBuffer recvBuf;
/// current offset in current rx fragment buffer
size_t recvBufOffset;
/// rx fragment message body
AlignedBuffer< FragmentBodySize > rxFragBody;
/// the next message id for tx
uint32_t m_NextTXMsgID;
/// the next message id for rx
uint32_t m_NextRXMsgID;
/// messages we are recving right now
std::unordered_map< uint32_t, InboundMessage > m_RecvMsgs;
/// are we stalled or nah?
bool stalled = false;
/// mark session as alive
void
Alive();
/// base
Session(LinkLayer* p);
/// outbound
Session(LinkLayer* p, utp_socket* s, const RouterContact& rc,
const AddressInfo& addr);
/// inbound
Session(LinkLayer* p, utp_socket* s, const Addr& remote);
enum State
{
eInitial, // initial state
eConnecting, // we are connecting
eLinkEstablished, // when utp connection is established
eCryptoHandshake, // crypto handshake initiated
eSessionReady, // session is ready
eClose // utp connection is closed
};
/// get router
// llarp::Router*
// Router();
llarp::Crypto*
Crypto();
/// session state, call EnterState(State) to set
State state;
/// hook for utp for when we have established a connection
void
OnLinkEstablished(LinkLayer* p);
/// switch states
void
EnterState(State st);
Session();
~Session();
/// handle LIM after handshake
bool
GotSessionRenegotiate(const LinkIntroMessage* msg);
/// re negotiate session with our new local RC
bool
Rehandshake();
/// pump tx queue
void
PumpWrite();
void
DoPump();
/// verify a fragment buffer and the decrypt it
/// buf is assumed to be FragmentBufferSize bytes long
bool
VerifyThenDecrypt(const byte_t* buf);
/// encrypt a fragment then hash the ciphertext
bool
EncryptThenHash(const byte_t* ptr, uint32_t msgid, uint16_t sz,
uint16_t remain);
/// queue a fully formed message
bool
QueueWriteBuffers(llarp_buffer_t buf);
/// prune expired inbound messages
void
PruneInboundMessages(llarp_time_t now);
/// do low level connect
void
Connect();
/// handle outbound connection made
void
OutboundLinkEstablished(LinkLayer* p);
// send first message
void
OutboundHandshake();
// do key exchange for handshake
bool
DoKeyExchange(transport_dh_func dh, SharedSecret& K,
const KeyExchangeNonce& n, const PubKey& other,
const SecretKey& secret);
/// does K = HS(K + A)
bool
MutateKey(SharedSecret& K, const AlignedBuffer< 24 >& A);
void
TickImpl(llarp_time_t now);
/// close session
void
Close();
/// low level read
bool
Recv(const byte_t* buf, size_t sz);
/// handle inbound LIM
bool
InboundLIM(const LinkIntroMessage* msg);
/// handle outbound LIM
bool
OutboundLIM(const LinkIntroMessage* msg);
/// return true if timed out
bool
IsTimedOut(llarp_time_t now) const;
/// get remote identity pubkey
const PubKey&
RemotePubKey() const;
/// get remote address
Addr
RemoteEndpoint();
/// get parent link
ILinkLayer*
GetParent();
void
MarkEstablished();
};
struct LinkLayer final : public ILinkLayer
{
utp_context* _utp_ctx = nullptr;
llarp::Crypto* _crypto = nullptr;
// low level read callback
static uint64
OnRead(utp_callback_arguments* arg);
// low level sendto callback
static uint64
SendTo(utp_callback_arguments* arg);
/// error callback
static uint64
OnError(utp_callback_arguments* arg);
/// state change callback
static uint64
OnStateChange(utp_callback_arguments*);
/// accept callback
static uint64
OnAccept(utp_callback_arguments*);
/// logger callback
static uint64
OnLog(utp_callback_arguments* arg);
/// construct
LinkLayer(llarp::Crypto* crypto, const SecretKey& routerEncSecret,
llarp::GetRCFunc getrc, llarp::LinkMessageHandler h,
llarp::SignBufferFunc sign,
llarp::SessionEstablishedHandler established,
llarp::SessionRenegotiateHandler reneg,
llarp::TimeoutHandler timeout,
llarp::SessionClosedHandler closed);
/// destruct
~LinkLayer();
/// get AI rank
uint16_t
Rank() const;
/// handle low level recv
void
RecvFrom(const Addr& from, const void* buf, size_t sz);
#ifdef __linux__
/// process ICMP stuff on linux
void
ProcessICMP();
#endif
llarp::Crypto*
Crypto();
/// pump sessions
void
Pump();
/// stop link layer
void
Stop();
/// rengenerate transport keypair
bool
KeyGen(SecretKey& k);
/// do tick
void
Tick(llarp_time_t now);
/// create new outbound session
ILinkSession*
NewOutboundSession(const RouterContact& rc, const AddressInfo& addr);
/// create new socket
utp_socket*
NewSocket();
/// get ai name
const char*
Name() const;
};
} // namespace utp
} // namespace llarp
#endif