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lokinet/llarp/quic/connection.cpp
Jason Rhinelander 869b362572 Attempt fix to work around gcc-8 warning
2021-04-19 13:30:00 -03:00

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#include "connection.hpp"
#include "client.hpp"
#include "server.hpp"
#include <limits>
#include <llarp/util/logging/logger.hpp>
#include <llarp/util/logging/buffer.hpp>
#include <cassert>
#include <charconv>
#include <cstring>
#include <iostream>
#include <uvw/async.h>
#include <uvw/poll.h>
#include <uvw/timer.h>
#include <iterator>
#include <oxenmq/hex.h>
#include <oxenmq/bt_serialize.h>
extern "C"
{
#include <sodium/randombytes.h>
}
namespace llarp::quic
{
ConnectionID::ConnectionID(const uint8_t* cid, size_t length)
{
assert(length <= max_size());
datalen = length;
std::memmove(data, cid, datalen);
}
std::ostream&
operator<<(std::ostream& o, const ConnectionID& c)
{
return o << oxenmq::to_hex(c.data, c.data + c.datalen);
}
ConnectionID
ConnectionID::random(size_t size)
{
ConnectionID r;
r.datalen = std::min(size, ConnectionID::max_size());
randombytes_buf(r.data, r.datalen);
return r;
}
namespace
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
constexpr int FAIL = NGTCP2_ERR_CALLBACK_FAILURE;
int
client_initial(ngtcp2_conn* conn_, void* user_data)
{
LogTrace("######################", __func__);
// Initialization the connection and send our transport parameters to the server. This will
// put the connection into NGTCP2_CS_CLIENT_WAIT_HANDSHAKE state.
return static_cast<Connection*>(user_data)->init_client();
}
int
recv_client_initial(ngtcp2_conn* conn_, const ngtcp2_cid* dcid, void* user_data)
{
LogTrace("######################", __func__);
// New incoming connection from a client: our server connection starts out here in state
// NGTCP2_CS_SERVER_INITIAL, but we should immediately get into recv_crypto_data because the
// initial client packet should contain the client's transport parameters.
auto& conn = *static_cast<Connection*>(user_data);
assert(conn_ == conn.conn.get());
if (0 != conn.setup_server_crypto_initial())
return FAIL;
return 0;
}
int
recv_crypto_data(
ngtcp2_conn* conn_,
ngtcp2_crypto_level crypto_level,
uint64_t offset,
const uint8_t* rawdata,
size_t rawdatalen,
void* user_data)
{
std::basic_string_view data{rawdata, rawdatalen};
LogTrace("Receiving crypto data @ level ", crypto_level, " ", buffer_printer{data});
auto& conn = *static_cast<Connection*>(user_data);
switch (crypto_level)
{
case NGTCP2_CRYPTO_LEVEL_EARLY:
// We don't currently use or support 0rtt
LogWarn("Invalid EARLY crypto level");
return FAIL;
case NGTCP2_CRYPTO_LEVEL_INITIAL:
// "Initial" level means we are still handshaking; if we are server then we receive
// the client's transport params (sent in client_initial, above) and blast ours
// back. If we are a client then getting here means we received a response from the
// server, which is that returned server transport params.
if (auto rv = conn.recv_initial_crypto(data); rv != 0)
return rv;
if (ngtcp2_conn_is_server(conn))
{
if (auto rv = conn.send_magic(NGTCP2_CRYPTO_LEVEL_INITIAL); rv != 0)
return rv;
if (auto rv = conn.send_transport_params(NGTCP2_CRYPTO_LEVEL_HANDSHAKE); rv != 0)
return rv;
}
break;
case NGTCP2_CRYPTO_LEVEL_HANDSHAKE:
if (!ngtcp2_conn_is_server(conn))
{
if (auto rv = conn.recv_transport_params(data); rv != 0)
return rv;
// At this stage of the protocol with TLS the client sends back TLS info so that
// the server can install our rx key; we have to send *something* back to invoke
// the server's HANDSHAKE callback (so that it knows handshake is complete) so
// send the magic again.
if (auto rv = conn.send_magic(NGTCP2_CRYPTO_LEVEL_HANDSHAKE); rv != 0)
return rv;
}
else
{
// Check that we received the above as expected
if (data != handshake_magic)
{
LogWarn("Invalid handshake crypto frame from client: did not find expected magic");
return NGTCP2_ERR_CALLBACK_FAILURE;
}
}
conn.complete_handshake();
break;
case NGTCP2_CRYPTO_LEVEL_APPLICATION:
// if (!conn.init_tx_key())
// return FAIL;
break;
default:
LogWarn("Unhandled crypto_level ", crypto_level);
return FAIL;
}
conn.io_ready();
return 0;
}
int
encrypt(
uint8_t* dest,
const ngtcp2_crypto_aead* aead,
const ngtcp2_crypto_aead_ctx* aead_ctx,
const uint8_t* plaintext,
size_t plaintextlen,
const uint8_t* nonce,
size_t noncelen,
const uint8_t* ad,
size_t adlen)
{
LogTrace("######################", __func__);
LogTrace("Lengths: ", plaintextlen, "+", noncelen, "+", adlen);
if (dest != plaintext)
std::memmove(dest, plaintext, plaintextlen);
return 0;
}
int
decrypt(
uint8_t* dest,
const ngtcp2_crypto_aead* aead,
const ngtcp2_crypto_aead_ctx* aead_ctx,
const uint8_t* ciphertext,
size_t ciphertextlen,
const uint8_t* nonce,
size_t noncelen,
const uint8_t* ad,
size_t adlen)
{
LogTrace("######################", __func__);
LogTrace("Lengths: ", ciphertextlen, "+", noncelen, "+", adlen);
if (dest != ciphertext)
std::memmove(dest, ciphertext, ciphertextlen);
return 0;
}
int
hp_mask(
uint8_t* dest,
const ngtcp2_crypto_cipher* hp,
const ngtcp2_crypto_cipher_ctx* hp_ctx,
const uint8_t* sample)
{
LogTrace("######################", __func__);
memset(dest, 0, NGTCP2_HP_MASKLEN);
return 0;
}
int
recv_stream_data(
ngtcp2_conn* conn,
uint32_t flags,
int64_t stream_id,
uint64_t offset,
const uint8_t* data,
size_t datalen,
void* user_data,
void* stream_user_data)
{
LogTrace("######################", __func__);
return static_cast<Connection*>(user_data)->stream_receive(
{stream_id},
{reinterpret_cast<const std::byte*>(data), datalen},
flags & NGTCP2_STREAM_DATA_FLAG_FIN);
}
int
acked_stream_data_offset(
ngtcp2_conn* conn_,
int64_t stream_id,
uint64_t offset,
uint64_t datalen,
void* user_data,
void* stream_user_data)
{
LogTrace("######################", __func__);
LogTrace("Ack [", offset, ",", offset + datalen, ")");
return static_cast<Connection*>(user_data)->stream_ack({stream_id}, datalen);
}
int
stream_open(ngtcp2_conn* conn, int64_t stream_id, void* user_data)
{
LogTrace("######################", __func__);
return static_cast<Connection*>(user_data)->stream_opened({stream_id});
}
int
stream_close_cb(
ngtcp2_conn* conn,
int64_t stream_id,
uint64_t app_error_code,
void* user_data,
void* stream_user_data)
{
LogTrace("######################", __func__);
static_cast<Connection*>(user_data)->stream_closed({stream_id}, app_error_code);
return 0;
}
// (client only)
int
recv_retry(ngtcp2_conn* conn, const ngtcp2_pkt_hd* hd, void* user_data)
{
LogTrace("######################", __func__);
LogError("FIXME UNIMPLEMENTED ", __func__);
// FIXME
return 0;
}
int
extend_max_local_streams_bidi(ngtcp2_conn* conn_, uint64_t max_streams, void* user_data)
{
LogTrace("######################", __func__);
auto& conn = *static_cast<Connection*>(user_data);
if (conn.on_stream_available)
if (uint64_t left = ngtcp2_conn_get_streams_bidi_left(conn); left > 0)
conn.on_stream_available(conn);
return 0;
}
int
rand(
uint8_t* dest,
size_t destlen,
const ngtcp2_rand_ctx* rand_ctx,
[[maybe_unused]] ngtcp2_rand_usage usage)
{
LogTrace("######################", __func__);
randombytes_buf(dest, destlen);
return 0;
}
int
get_new_connection_id(
ngtcp2_conn* conn_, ngtcp2_cid* cid_, uint8_t* token, size_t cidlen, void* user_data)
{
LogTrace("######################", __func__);
auto& conn = *static_cast<Connection*>(user_data);
auto cid = conn.make_alias_id(cidlen);
assert(cid.datalen == cidlen);
*cid_ = cid;
conn.endpoint.make_stateless_reset_token(cid, token);
LogDebug(
"make stateless reset token ",
oxenmq::to_hex(token, token + NGTCP2_STATELESS_RESET_TOKENLEN));
return 0;
}
int
remove_connection_id(ngtcp2_conn* conn, const ngtcp2_cid* cid, void* user_data)
{
LogTrace("######################", __func__);
LogError("FIXME UNIMPLEMENTED ", __func__);
// FIXME
return 0;
}
int
update_key(
ngtcp2_conn* conn,
uint8_t* rx_secret,
uint8_t* tx_secret,
ngtcp2_crypto_aead_ctx* rx_aead_ctx,
uint8_t* rx_iv,
ngtcp2_crypto_aead_ctx* tx_aead_ctx,
uint8_t* tx_iv,
const uint8_t* current_rx_secret,
const uint8_t* current_tx_secret,
size_t secretlen,
void* user_data)
{
// This is a no-op since we don't encrypt anything in the first place
return 0;
}
#pragma GCC diagnostic pop
} // namespace
#ifndef NDEBUG
extern "C" inline void
ngtcp_trace_logger([[maybe_unused]] void* user_data, const char* fmt, ...)
{
va_list ap;
va_start(ap, fmt);
if (char* msg; vasprintf(&msg, fmt, ap) >= 0)
{
LogTraceExplicit("external/ngtcp2/*.c", 0, msg);
std::free(msg);
}
va_end(ap);
}
#endif
io_result
Connection::send()
{
assert(send_buffer_size <= send_buffer.size());
io_result rv{};
bstring_view send_data{send_buffer.data(), send_buffer_size};
if (!send_data.empty())
{
rv = endpoint.send_packet(path.remote, send_data, send_pkt_info.ecn);
}
return rv;
}
std::tuple<ngtcp2_settings, ngtcp2_transport_params, ngtcp2_callbacks>
Connection::init()
{
auto loop = endpoint.get_loop();
io_trigger = loop->resource<uvw::AsyncHandle>();
io_trigger->on<uvw::AsyncEvent>([this](auto&, auto&) { on_io_ready(); });
retransmit_timer = loop->resource<uvw::TimerHandle>();
retransmit_timer->on<uvw::TimerEvent>([this](auto&, auto&) {
LogTrace("Retransmit timer fired!");
if (auto rv = ngtcp2_conn_handle_expiry(*this, get_timestamp()); rv != 0)
{
LogWarn("expiry handler invocation returned an error: ", ngtcp2_strerror(rv));
endpoint.close_connection(*this, ngtcp2_err_infer_quic_transport_error_code(rv), false);
}
else
{
flush_streams();
}
});
retransmit_timer->start(0ms, 0ms);
auto result = std::tuple<ngtcp2_settings, ngtcp2_transport_params, ngtcp2_callbacks>{};
auto& [settings, tparams, cb] = result;
cb.recv_crypto_data = recv_crypto_data;
cb.encrypt = encrypt;
cb.decrypt = decrypt;
cb.hp_mask = hp_mask;
cb.recv_stream_data = recv_stream_data;
cb.acked_stream_data_offset = acked_stream_data_offset;
cb.stream_open = stream_open;
cb.stream_close = stream_close_cb;
cb.extend_max_local_streams_bidi = extend_max_local_streams_bidi;
cb.rand = rand;
cb.get_new_connection_id = get_new_connection_id;
cb.remove_connection_id = remove_connection_id;
cb.update_key = update_key;
ngtcp2_settings_default(&settings);
#ifndef NDEBUG
settings.log_printf = ngtcp_trace_logger;
#endif
settings.initial_ts = get_timestamp();
// FIXME: IPv6
settings.max_udp_payload_size = NGTCP2_MAX_PKTLEN_IPV4;
settings.cc_algo = NGTCP2_CC_ALGO_CUBIC;
// settings.initial_rtt = ???; # NGTCP2's default is 333ms
ngtcp2_transport_params_default(&tparams);
// Connection level flow control window:
tparams.initial_max_data = CONNECTION_BUFFER;
// Max send buffer for a streams (local is for streams we initiate, remote is for replying on
// streams they initiate to us):
tparams.initial_max_stream_data_bidi_local = STREAM_BUFFER;
tparams.initial_max_stream_data_bidi_remote = STREAM_BUFFER;
// Max *cumulative* streams we support on a connection:
tparams.initial_max_streams_bidi = STREAM_LIMIT;
tparams.initial_max_streams_uni = 0;
tparams.max_idle_timeout = std::chrono::nanoseconds(IDLE_TIMEOUT).count();
tparams.active_connection_id_limit = 8;
LogDebug("Done basic connection initialization");
return result;
}
Connection::Connection(
Server& s, const ConnectionID& base_cid_, ngtcp2_pkt_hd& header, const Path& path)
: endpoint{s}, base_cid{base_cid_}, dest_cid{header.scid}, path{path}
{
auto [settings, tparams, cb] = init();
cb.recv_client_initial = recv_client_initial;
// ConnectionIDs are a little complicated:
// - when a client creates a new connection to us, it creates a random source connection ID
// *and* a random destination connection id. The server won't have that connection ID, of
// course, but we use it to recognize that we should try accepting it as a new connection.
// - When we talk to the client we use the random source connection ID that it generated as our
// destination connection ID.
// - We choose our own source ID, however: we *don't* use the random one the client picked for
// us. Instead we generate a random one and sent it back as *our* source connection ID in the
// reply to the client.
// - the client still needs to match up that reply with that request, and so we include the
// destination connection ID that the client generated for us in the transport parameters as
// the original_dcid: this lets the client match up the request, after which it can't promptly
// forget about it and start using the source CID that we gave it.
//
// So, in other words, the conversation goes like this:
// - Client: [SCID:clientid, DCID:randomid, TRANSPORT_PARAMS]
// - Server: [SCID:serverid, DCID:clientid TRANSPORT_PARAMS(origid=randomid)]
//
// - For the client, .base_cid={clientid} and .dest_cid={randomid} initially but gets updated to
// .dest_cid={serverid} when we hear back from the server.
// - For the server, .base_cid={serverid} and .dest_cid={clientid}
tparams.original_dcid = header.dcid;
LogDebug("original_dcid is now set to ", ConnectionID(tparams.original_dcid));
settings.token = header.token;
// FIXME is this required?
randombytes_buf(tparams.stateless_reset_token, sizeof(tparams.stateless_reset_token));
tparams.stateless_reset_token_present = 1;
ngtcp2_conn* connptr;
LogDebug("server_new, path=", path);
if (auto rv = ngtcp2_conn_server_new(
&connptr,
&dest_cid,
&base_cid,
path,
header.version,
&cb,
&settings,
&tparams,
nullptr /*default mem allocator*/,
this);
rv != 0)
throw std::runtime_error{"Failed to initialize server connection: "s + ngtcp2_strerror(rv)};
conn.reset(connptr);
LogDebug("Created new server conn ", base_cid);
}
Connection::Connection(
Client& c, const ConnectionID& scid, const Path& path, uint16_t tunnel_port)
: tunnel_port{tunnel_port}
, endpoint{c}
, base_cid{scid}
, dest_cid{ConnectionID::random()}
, path{path}
{
auto [settings, tparams, cb] = init();
assert(tunnel_port != 0);
cb.client_initial = client_initial;
cb.recv_retry = recv_retry;
// cb.extend_max_local_streams_bidi = extend_max_local_streams_bidi;
// cb.recv_new_token = recv_new_token;
ngtcp2_conn* connptr;
if (auto rv = ngtcp2_conn_client_new(
&connptr,
&dest_cid,
&scid,
path,
NGTCP2_PROTO_VER_V1,
&cb,
&settings,
&tparams,
nullptr,
this);
rv != 0)
throw std::runtime_error{"Failed to initialize client connection: "s + ngtcp2_strerror(rv)};
conn.reset(connptr);
LogDebug("Created new client conn ", scid);
}
Connection::~Connection()
{
if (io_trigger)
io_trigger->close();
if (retransmit_timer)
{
retransmit_timer->stop();
retransmit_timer->close();
}
}
void
Connection::io_ready()
{
io_trigger->send();
}
void
Connection::on_io_ready()
{
LogTrace(__func__);
flush_streams();
LogTrace("done ", __func__);
}
void
Connection::flush_streams()
{
// conn, path, pi, dest, destlen, and ts
std::optional<uint64_t> ts;
send_pkt_info = {};
auto add_stream_data =
[&](StreamID stream_id, const ngtcp2_vec* datav, size_t datalen, uint32_t flags = 0) {
std::array<ngtcp2_ssize, 2> result;
auto& [nwrite, consumed] = result;
if (!ts)
ts = get_timestamp();
LogTrace(
"send_buffer size=", send_buffer.size(), ", datalen=", datalen, ", flags=", flags);
nwrite = ngtcp2_conn_writev_stream(
conn.get(),
&path.path,
&send_pkt_info,
u8data(send_buffer),
send_buffer.size(),
&consumed,
NGTCP2_WRITE_STREAM_FLAG_MORE | flags,
stream_id.id,
datav,
datalen,
*ts);
return result;
};
auto send_packet = [&](auto nwrite) -> bool {
send_buffer_size = nwrite;
LogTrace("Sending ", send_buffer_size, "B packet");
auto sent = send();
if (sent.blocked())
{
schedule_retransmit();
return false;
}
send_buffer_size = 0;
if (!sent)
{
LogWarn("I/O error while trying to send packet: ", sent.str());
// FIXME: disconnect?
return false;
}
LogTrace("packet away!");
return true;
};
std::list<Stream*> strs;
for (auto& [stream_id, stream_ptr] : streams)
if (stream_ptr)
strs.push_back(stream_ptr.get());
// Maximum number of stream data packets to send out at once; if we reach this then we'll
// schedule another event loop call of ourselves (so that we don't starve the loop).
constexpr int max_stream_packets = 15;
int stream_packets = 0;
while (!strs.empty() && stream_packets < max_stream_packets)
{
for (auto it = strs.begin(); it != strs.end();)
{
auto& stream = **it;
auto bufs = stream.pending();
std::vector<ngtcp2_vec> vecs;
vecs.reserve(bufs.size());
std::transform(bufs.begin(), bufs.end(), std::back_inserter(vecs), [](const auto& buf) {
return ngtcp2_vec{const_cast<uint8_t*>(u8data(buf)), buf.size()};
});
#ifndef NDEBUG
{
std::string buf_sizes;
for (auto& b : bufs)
{
if (!buf_sizes.empty())
buf_sizes += '+';
buf_sizes += std::to_string(b.size());
}
LogDebug("Sending ", buf_sizes.empty() ? "no" : buf_sizes, " data for ", stream.id());
}
#endif
uint32_t extra_flags = 0;
if (stream.is_closing && !stream.sent_fin)
{
LogDebug("Sending FIN");
extra_flags |= NGTCP2_WRITE_STREAM_FLAG_FIN;
stream.sent_fin = true;
}
else if (stream.is_new)
{
stream.is_new = false;
}
auto [nwrite, consumed] =
add_stream_data(stream.id(), vecs.data(), vecs.size(), extra_flags);
LogTrace(
"add_stream_data for stream ", stream.id(), " returned [", nwrite, ",", consumed, "]");
if (nwrite > 0)
{
if (consumed >= 0)
{
LogTrace("consumed ", consumed, " bytes from stream ", stream.id());
stream.wrote(consumed);
}
LogTrace("Sending stream data packet");
if (!send_packet(nwrite))
return;
++stream_packets;
++it;
continue;
}
switch (nwrite)
{
case 0:
LogTrace(
"Done stream writing to ",
stream.id(),
" (either stream is congested or we have nothing else to send right now)");
assert(consumed <= 0);
break;
case NGTCP2_ERR_WRITE_MORE:
LogTrace(
"consumed ", consumed, " bytes from stream ", stream.id(), " and have space left");
stream.wrote(consumed);
if (stream.unsent() > 0)
{
// We have more to send on this stream, so keep us in the queue
++it;
continue;
}
break;
case NGTCP2_ERR_STREAM_DATA_BLOCKED:
LogDebug("cannot add to stream ", stream.id(), " right now: stream is blocked");
break;
case NGTCP2_ERR_STREAM_SHUT_WR:
LogDebug("cannot write to ", stream.id(), ": stream is shut down");
break;
default:
assert(consumed <= 0);
LogWarn("Error writing to stream ", stream.id(), ": ", ngtcp2_strerror(nwrite));
break;
}
it = strs.erase(it);
}
}
// Now try more with stream id -1 and no data: this takes care of things like initial handshake
// packets, and also finishes off any partially-filled packet from above.
for (;;)
{
auto [nwrite, consumed] = add_stream_data(StreamID{}, nullptr, 0);
LogTrace("add_stream_data for non-stream returned [", nwrite, ",", consumed, "]");
assert(consumed <= 0);
if (nwrite == NGTCP2_ERR_WRITE_MORE)
{
LogTrace("Writing non-stream data, and have space left");
continue;
}
if (nwrite < 0)
{
LogWarn("Error writing non-stream data: ", ngtcp2_strerror(nwrite));
break;
}
if (nwrite == 0)
{
LogTrace("Nothing else to write for non-stream data for now (or we are congested)");
ngtcp2_conn_stat cstat;
ngtcp2_conn_get_conn_stat(*this, &cstat);
LogTrace("Current unacked bytes in flight: ", cstat.bytes_in_flight);
break;
}
LogTrace("Sending non-stream data packet");
if (!send_packet(nwrite))
return;
}
schedule_retransmit();
}
void
Connection::schedule_retransmit()
{
auto exp = ngtcp2_conn_get_expiry(*this);
if (exp == std::numeric_limits<decltype(exp)>::max())
{
LogTrace("no retransmit currently needed");
retransmit_timer->stop();
return;
}
auto expiry = std::chrono::nanoseconds{static_cast<std::chrono::nanoseconds::rep>(exp)};
auto expires_in = std::max(
0ms,
std::chrono::duration_cast<std::chrono::milliseconds>(
expiry - get_time().time_since_epoch()));
LogDebug("Next retransmit in ", expires_in.count(), "ms");
retransmit_timer->stop();
retransmit_timer->start(expires_in, 0ms);
}
int
Connection::stream_opened(StreamID id)
{
LogDebug("New stream ", id);
auto* serv = server();
if (!serv)
{
LogWarn("We are a client, incoming streams are not accepted");
return NGTCP2_ERR_CALLBACK_FAILURE;
}
std::shared_ptr<Stream> stream{new Stream{*this, id, endpoint.default_stream_buffer_size}};
stream->stream_id = id;
bool good = true;
if (serv->stream_open_callback)
good = serv->stream_open_callback(*stream, tunnel_port);
if (!good)
{
LogDebug("stream_open_callback returned failure, dropping stream ", id);
ngtcp2_conn_shutdown_stream(*this, id.id, 1);
io_ready();
return NGTCP2_ERR_CALLBACK_FAILURE;
}
[[maybe_unused]] auto [it, ins] = streams.emplace(id, std::move(stream));
assert(ins);
LogDebug("Created new incoming stream ", id);
return 0;
}
int
Connection::stream_receive(StreamID id, const bstring_view data, bool fin)
{
auto str = get_stream(id);
if (!str->data_callback)
LogDebug("Dropping incoming data on stream ", str->id(), ": stream has no data callback set");
else
{
bool good = false;
try
{
str->data_callback(*str, data);
good = true;
}
catch (const std::exception& e)
{
LogWarn(
"Stream ",
str->id(),
" data callback raised exception (",
e.what(),
"); closing stream with app code ",
STREAM_ERROR_EXCEPTION);
}
catch (...)
{
LogWarn(
"Stream ",
str->id(),
" data callback raised an unknown exception; closing stream with app code ",
STREAM_ERROR_EXCEPTION);
}
if (!good)
{
str->close(STREAM_ERROR_EXCEPTION);
return NGTCP2_ERR_CALLBACK_FAILURE;
}
}
if (fin)
{
LogTrace("Stream ", str->id(), " closed by remote");
// Don't cleanup here; stream_closed is going to be called right away to deal with that
}
else
{
ngtcp2_conn_extend_max_stream_offset(*this, id.id, data.size());
ngtcp2_conn_extend_max_offset(*this, data.size());
}
return 0;
}
void
Connection::stream_closed(StreamID id, uint64_t app_code)
{
assert(ngtcp2_is_bidi_stream(id.id));
LogDebug(id, " closed with code ", app_code);
auto it = streams.find(id);
if (it == streams.end())
return;
auto& stream = *it->second;
const bool was_closing = stream.is_closing;
stream.is_closing = stream.is_shutdown = true;
if (!was_closing && stream.close_callback)
{
LogDebug("Invoke stream close callback");
std::optional<uint64_t> code;
if (app_code != 0)
code = app_code;
stream.close_callback(stream, code);
}
LogDebug("Erasing stream ", id, " from ", (void*)it->second.get());
streams.erase(it);
if (!ngtcp2_conn_is_local_stream(*this, id.id))
ngtcp2_conn_extend_max_streams_bidi(*this, 1);
io_ready(); // Probably superfluous but sometimes we might need to send a FIN or something.
}
int
Connection::stream_ack(StreamID id, size_t size)
{
if (auto it = streams.find(id); it != streams.end())
{
it->second->acknowledge(size);
return 0;
}
return NGTCP2_ERR_CALLBACK_FAILURE;
}
Server*
Connection::server()
{
return dynamic_cast<Server*>(&endpoint);
}
Client*
Connection::client()
{
return dynamic_cast<Client*>(&endpoint);
}
int
Connection::setup_server_crypto_initial()
{
auto* s = server();
assert(s);
s->null_crypto.server_initial(*this);
io_ready();
return 0;
}
ConnectionID
Connection::make_alias_id(size_t cidlen)
{
return endpoint.add_connection_id(*this, cidlen);
}
bool
Connection::get_handshake_completed()
{
return ngtcp2_conn_get_handshake_completed(*this) != 0;
}
int
Connection::get_streams_available()
{
uint64_t left = ngtcp2_conn_get_streams_bidi_left(*this);
constexpr int max_int = std::numeric_limits<int>::max();
if (left > static_cast<uint64_t>(max_int))
return max_int;
return static_cast<int>(left);
}
const std::shared_ptr<Stream>&
Connection::open_stream(Stream::data_callback_t data_cb, Stream::close_callback_t close_cb)
{
std::shared_ptr<Stream> stream{new Stream{
*this, std::move(data_cb), std::move(close_cb), endpoint.default_stream_buffer_size}};
if (int rv = ngtcp2_conn_open_bidi_stream(*this, &stream->stream_id.id, stream.get()); rv != 0)
throw std::runtime_error{"Stream creation failed: "s + ngtcp2_strerror(rv)};
auto& str = streams[stream->stream_id];
str = std::move(stream);
return str;
}
const std::shared_ptr<Stream>&
Connection::get_stream(StreamID s) const
{
return streams.at(s);
}
int
Connection::init_client()
{
endpoint.null_crypto.client_initial(*this);
if (int rv = send_magic(NGTCP2_CRYPTO_LEVEL_INITIAL); rv != 0)
return rv;
if (int rv = send_transport_params(NGTCP2_CRYPTO_LEVEL_INITIAL); rv != 0)
return rv;
io_ready();
return 0;
}
int
Connection::recv_initial_crypto(std::basic_string_view<uint8_t> data)
{
if (data.substr(0, handshake_magic.size()) != handshake_magic)
{
LogWarn("Invalid initial crypto frame: did not find expected magic prefix");
return NGTCP2_ERR_CALLBACK_FAILURE;
}
data.remove_prefix(handshake_magic.size());
const bool is_server = ngtcp2_conn_is_server(*this);
if (is_server)
{
// For a server, we receive the transport parameters in the initial packet (prepended by the
// magic that we just removed):
if (auto rv = recv_transport_params(data); rv != 0)
return rv;
}
else
{
// For a client our initial crypto data should be just the magic string (the packet also
// contains transport parameters, but they are at HANDSHAKE crypto level and so will result
// in a second callback to handle them).
if (!data.empty())
{
LogWarn("Invalid initial crypto frame: unexpected post-magic data found");
return NGTCP2_ERR_CALLBACK_FAILURE;
}
}
endpoint.null_crypto.install_rx_handshake_key(*this);
endpoint.null_crypto.install_tx_handshake_key(*this);
if (is_server)
endpoint.null_crypto.install_tx_key(*this);
return 0;
}
void
Connection::complete_handshake()
{
endpoint.null_crypto.install_rx_key(*this);
if (!ngtcp2_conn_is_server(*this))
endpoint.null_crypto.install_tx_key(*this);
ngtcp2_conn_handshake_completed(*this);
if (on_handshake_complete)
{
on_handshake_complete(*this);
on_handshake_complete = nullptr;
}
}
// ngtcp2 doesn't expose the varint encoding, but it's fairly simple:
// 0bXXyyyyyy -- XX indicates the encoded size (00=1, 01=2, 10=4, 11=8) and the rest of the bits
// (6, 14, 30, or 62) are the number, with bytes in network order for >6-bit values.
// Returns {value, consumed} where consumed is the number of bytes consumed, or 0 on failure.
static constexpr std::pair<uint64_t, size_t>
decode_varint(std::basic_string_view<uint8_t> data)
{
std::pair<uint64_t, size_t> result = {0, 0};
auto& [val, enc_size] = result;
if (data.empty())
return result;
enc_size = 1 << (data[0] >> 6); // first two bits are log₂ of the length
if (data.size() < enc_size)
{
enc_size = 0;
return result;
}
val = data[0] & 0b0011'1111;
for (size_t i = 1; i < enc_size; i++)
val = (val << 8) | data[i];
return result;
}
// Encodes an unsigned integer in QUIC encoding format; return the bytes and the length (bytes
// beyond `length` are uninitialized).
static constexpr std::pair<std::array<uint8_t, 8>, uint8_t>
encode_varint(uint64_t val)
{
assert(val < (1ULL << 62));
std::pair<std::array<uint8_t, 8>, uint8_t> result;
uint8_t size = val < (1ULL << 6) ? 0 : val < (1ULL << 14) ? 1 : val < (1ULL << 30) ? 2 : 3;
auto& [enc, len] = result;
len = 1 << size;
for (uint8_t i = 1; i <= len; i++)
{
enc[len - i] = val & 0xff;
val >>= 8;
}
enc[0] = (enc[0] & 0b00'111111) | (size << 6);
enc[0] |= size << 6;
return result;
}
// We add some lokinet-specific data into the transport request and *always* as the first
// transport parameter, but we do it in a way that the parameter gets ignored by the QUIC
// protocol, which encodes as {varint[code], varint[length], data}, and requires a code value
// 31*N+27 (for integer N). Naturally we use N=42, which gives us 1329=0b10100110001 which
// encodes in QUIC as 0b01000101 0b00110001 (the first two bits of the first byte give the integer
// size, and the rest are the value in network order).
static constexpr uint64_t lokinet_transport_param_N = 42;
static constexpr auto lokinet_metadata_code_raw =
encode_varint(31 * lokinet_transport_param_N + 27);
static constexpr std::basic_string_view<uint8_t> lokinet_metadata_code{
lokinet_metadata_code_raw.first.data(), lokinet_metadata_code_raw.second};
static_assert(
lokinet_metadata_code.size() == 2 && lokinet_metadata_code[0] == 0b01000101
&& lokinet_metadata_code[1] == 0b00110001);
int
Connection::recv_transport_params(std::basic_string_view<uint8_t> data)
{
if (data.substr(0, lokinet_metadata_code.size()) != lokinet_metadata_code)
{
LogWarn("transport params did not begin with expected lokinet metadata");
return NGTCP2_ERR_TRANSPORT_PARAM;
}
auto [meta_len, meta_len_bytes] = decode_varint(data.substr(lokinet_metadata_code.size()));
if (meta_len_bytes == 0)
{
LogWarn("transport params lokinet metadata has truncated size");
return NGTCP2_ERR_MALFORMED_TRANSPORT_PARAM;
}
std::string_view lokinet_metadata{
reinterpret_cast<const char*>(
data.substr(lokinet_metadata_code.size() + meta_len_bytes).data()),
static_cast<std::size_t>(meta_len)};
LogDebug("Received bencoded lokinet metadata: ", buffer_printer{lokinet_metadata});
uint16_t port;
try
{
oxenmq::bt_dict_consumer meta{lokinet_metadata};
// '#' contains the port the client wants us to forward to
if (!meta.skip_until("#"))
{
LogWarn("transport params # (port) is missing but required");
return NGTCP2_ERR_TRANSPORT_PARAM;
}
port = meta.consume_integer<uint16_t>();
if (port == 0)
{
LogWarn("transport params tunnel port (#) is invalid: 0 is not permitted");
return NGTCP2_ERR_TRANSPORT_PARAM;
}
LogDebug("decoded lokinet tunnel port = ", port);
}
catch (const oxenmq::bt_deserialize_invalid& c)
{
LogWarn("transport params lokinet metadata is invalid: ", c.what());
return NGTCP2_ERR_TRANSPORT_PARAM;
}
const bool is_server = ngtcp2_conn_is_server(*this);
if (is_server)
{
tunnel_port = port;
}
else
{
// Make sure the server reflected the proper port
if (tunnel_port != port)
{
LogWarn("server returned invalid port; expected ", tunnel_port, ", got ", port);
return NGTCP2_ERR_TRANSPORT_PARAM;
}
}
ngtcp2_transport_params params;
auto exttype = is_server ? NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO
: NGTCP2_TRANSPORT_PARAMS_TYPE_ENCRYPTED_EXTENSIONS;
auto rv = ngtcp2_decode_transport_params(&params, exttype, data.data(), data.size());
LogDebug("Decode transport params ", rv == 0 ? "success" : "fail: "s + ngtcp2_strerror(rv));
LogTrace("params orig dcid = ", ConnectionID(params.original_dcid));
LogTrace("params init scid = ", ConnectionID(params.initial_scid));
if (rv == 0)
{
rv = ngtcp2_conn_set_remote_transport_params(*this, &params);
LogDebug(
"Set remote transport params ", rv == 0 ? "success" : "fail: "s + ngtcp2_strerror(rv));
}
if (rv != 0)
{
ngtcp2_conn_set_tls_error(*this, rv);
return rv;
}
return 0;
}
// Sends our magic string at the given level. This fixed magic string is taking the place of TLS
// parameters in full QUIC.
int
Connection::send_magic(ngtcp2_crypto_level level)
{
return ngtcp2_conn_submit_crypto_data(
*this, level, handshake_magic.data(), handshake_magic.size());
}
template <typename String>
static void
copy_and_advance(uint8_t*& buf, const String& s)
{
static_assert(sizeof(typename String::value_type) == 1, "not a char-compatible type");
std::memcpy(buf, s.data(), s.size());
buf += s.size();
}
// Sends transport parameters. `level` is expected to be INITIAL for clients (which send the
// transport parameters in the initial packet), or HANDSHAKE for servers.
int
Connection::send_transport_params(ngtcp2_crypto_level level)
{
ngtcp2_transport_params tparams;
ngtcp2_conn_get_local_transport_params(*this, &tparams);
assert(conn_buffer.empty());
static_assert(NGTCP2_MAX_PKTLEN_IPV4 > NGTCP2_MAX_PKTLEN_IPV6);
conn_buffer.resize(NGTCP2_MAX_PKTLEN_IPV4);
auto* buf = u8data(conn_buffer);
auto* bufend = buf + conn_buffer.size();
{
// Send our first parameter, the lokinet metadata, in a QUIC-compatible way (by using a
// reserved field code that QUIC parsers must ignore); currently we only include the port in
// here (from the client to tell the server what it's trying to reach, and reflected from
// the server for the client to verify).
std::string lokinet_metadata = bt_serialize(oxenmq::bt_dict{
{"#", tunnel_port},
});
copy_and_advance(buf, lokinet_metadata_code);
auto [bytes, size] = encode_varint(lokinet_metadata.size());
copy_and_advance(buf, std::basic_string_view{bytes.data(), size});
copy_and_advance(buf, lokinet_metadata);
assert(buf < bufend);
}
const bool is_server = ngtcp2_conn_is_server(*this);
auto exttype = is_server ? NGTCP2_TRANSPORT_PARAMS_TYPE_ENCRYPTED_EXTENSIONS
: NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO;
if (ngtcp2_ssize nwrite = ngtcp2_encode_transport_params(buf, bufend - buf, exttype, &tparams);
nwrite >= 0)
{
assert(nwrite > 0);
conn_buffer.resize(buf - u8data(conn_buffer) + nwrite);
}
else
{
conn_buffer.clear();
return nwrite;
}
LogDebug("encoded transport params: ", buffer_printer{conn_buffer});
return ngtcp2_conn_submit_crypto_data(*this, level, u8data(conn_buffer), conn_buffer.size());
}
} // namespace llarp::quic
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