diff options
Diffstat (limited to 'dnsdist-nghttp2-in.cc')
| -rw-r--r-- | dnsdist-nghttp2-in.cc | 1187 |
1 files changed, 1187 insertions, 0 deletions
diff --git a/dnsdist-nghttp2-in.cc b/dnsdist-nghttp2-in.cc new file mode 100644 index 0000000..32dc254 --- /dev/null +++ b/dnsdist-nghttp2-in.cc @@ -0,0 +1,1187 @@ +/* + * This file is part of PowerDNS or dnsdist. + * Copyright -- PowerDNS.COM B.V. and its contributors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * In addition, for the avoidance of any doubt, permission is granted to + * link this program with OpenSSL and to (re)distribute the binaries + * produced as the result of such linking. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "dnsdist-dnsparser.hh" +#include "dnsdist-doh-common.hh" +#include "dnsdist-nghttp2-in.hh" +#include "dnsdist-proxy-protocol.hh" +#include "dnsparser.hh" + +#if defined(HAVE_DNS_OVER_HTTPS) && defined(HAVE_NGHTTP2) + +#if 0 +class IncomingDoHCrossProtocolContext : public CrossProtocolContext +{ +public: + IncomingDoHCrossProtocolContext(IncomingHTTP2Connection::PendingQuery&& query, std::shared_ptr<IncomingHTTP2Connection> connection, IncomingHTTP2Connection::StreamID streamID): CrossProtocolContext(std::move(query.d_buffer)), d_connection(connection), d_query(std::move(query)) + { + } + + std::optional<std::string> getHTTPPath() const override + { + return d_query.d_path; + } + + std::optional<std::string> getHTTPScheme() const override + { + return d_query.d_scheme; + } + + std::optional<std::string> getHTTPHost() const override + { + return d_query.d_host; + } + + std::optional<std::string> getHTTPQueryString() const override + { + return d_query.d_queryString; + } + + std::optional<HeadersMap> getHTTPHeaders() const override + { + if (!d_query.d_headers) { + return std::nullopt; + } + return *d_query.d_headers; + } + + void handleResponse(PacketBuffer&& response, InternalQueryState&& state) override + { + auto conn = d_connection.lock(); + if (!conn) { + /* the connection has been closed in the meantime */ + return; + } + } + + void handleTimeout() override + { + auto conn = d_connection.lock(); + if (!conn) { + /* the connection has been closed in the meantime */ + return; + } + } + + ~IncomingDoHCrossProtocolContext() override + { + } + +private: + std::weak_ptr<IncomingHTTP2Connection> d_connection; + IncomingHTTP2Connection::PendingQuery d_query; + IncomingHTTP2Connection::StreamID d_streamID{-1}; +}; +#endif + +class IncomingDoHCrossProtocolContext : public DOHUnitInterface +{ +public: + IncomingDoHCrossProtocolContext(IncomingHTTP2Connection::PendingQuery&& query, const std::shared_ptr<IncomingHTTP2Connection>& connection, IncomingHTTP2Connection::StreamID streamID) : + d_connection(connection), d_query(std::move(query)), d_streamID(streamID) + { + } + IncomingDoHCrossProtocolContext(const IncomingDoHCrossProtocolContext&) = delete; + IncomingDoHCrossProtocolContext(IncomingDoHCrossProtocolContext&&) = delete; + IncomingDoHCrossProtocolContext& operator=(const IncomingDoHCrossProtocolContext&) = delete; + IncomingDoHCrossProtocolContext& operator=(IncomingDoHCrossProtocolContext&&) = delete; + + ~IncomingDoHCrossProtocolContext() override = default; + + [[nodiscard]] std::string getHTTPPath() const override + { + return d_query.d_path; + } + + [[nodiscard]] const std::string& getHTTPScheme() const override + { + return d_query.d_scheme; + } + + [[nodiscard]] const std::string& getHTTPHost() const override + { + return d_query.d_host; + } + + [[nodiscard]] std::string getHTTPQueryString() const override + { + return d_query.d_queryString; + } + + [[nodiscard]] const HeadersMap& getHTTPHeaders() const override + { + if (!d_query.d_headers) { + static const HeadersMap empty{}; + return empty; + } + return *d_query.d_headers; + } + + void setHTTPResponse(uint16_t statusCode, PacketBuffer&& body, const std::string& contentType = "") override + { + d_query.d_statusCode = statusCode; + d_query.d_response = std::move(body); + d_query.d_contentTypeOut = contentType; + } + + void handleUDPResponse(PacketBuffer&& response, InternalQueryState&& state, const std::shared_ptr<DownstreamState>& downstream_) override + { + std::unique_ptr<DOHUnitInterface> unit(this); + auto conn = d_connection.lock(); + if (!conn) { + /* the connection has been closed in the meantime */ + return; + } + + state.du = std::move(unit); + TCPResponse resp(std::move(response), std::move(state), nullptr, nullptr); + resp.d_ds = downstream_; + struct timeval now + { + }; + gettimeofday(&now, nullptr); + conn->handleResponse(now, std::move(resp)); + } + + void handleTimeout() override + { + std::unique_ptr<DOHUnitInterface> unit(this); + auto conn = d_connection.lock(); + if (!conn) { + /* the connection has been closed in the meantime */ + return; + } + struct timeval now + { + }; + gettimeofday(&now, nullptr); + TCPResponse resp; + resp.d_idstate.d_streamID = d_streamID; + conn->notifyIOError(now, std::move(resp)); + } + + std::weak_ptr<IncomingHTTP2Connection> d_connection; + IncomingHTTP2Connection::PendingQuery d_query; + IncomingHTTP2Connection::StreamID d_streamID{-1}; +}; + +void IncomingHTTP2Connection::handleResponse(const struct timeval& now, TCPResponse&& response) +{ + if (std::this_thread::get_id() != d_creatorThreadID) { + handleCrossProtocolResponse(now, std::move(response)); + return; + } + + auto& state = response.d_idstate; + if (state.forwardedOverUDP) { + dnsheader_aligned responseDH(response.d_buffer.data()); + + if (responseDH.get()->tc && state.d_packet && state.d_packet->size() > state.d_proxyProtocolPayloadSize && state.d_packet->size() - state.d_proxyProtocolPayloadSize > sizeof(dnsheader)) { + vinfolog("Response received from backend %s via UDP, for query %d received from %s via DoH, is truncated, retrying over TCP", response.d_ds->getNameWithAddr(), state.d_streamID, state.origRemote.toStringWithPort()); + auto& query = *state.d_packet; + dnsdist::PacketMangling::editDNSHeaderFromRawPacket(&query.at(state.d_proxyProtocolPayloadSize), [origID = state.origID](dnsheader& header) { + /* restoring the original ID */ + header.id = origID; + return true; + }); + + state.forwardedOverUDP = false; + bool proxyProtocolPayloadAdded = state.d_proxyProtocolPayloadSize > 0; + auto cpq = getCrossProtocolQuery(std::move(query), std::move(state), response.d_ds); + cpq->query.d_proxyProtocolPayloadAdded = proxyProtocolPayloadAdded; + if (g_tcpclientthreads && g_tcpclientthreads->passCrossProtocolQueryToThread(std::move(cpq))) { + return; + } + vinfolog("Unable to pass DoH query to a TCP worker thread after getting a TC response over UDP"); + notifyIOError(now, std::move(response)); + return; + } + } + + IncomingTCPConnectionState::handleResponse(now, std::move(response)); +} + +std::unique_ptr<DOHUnitInterface> IncomingHTTP2Connection::getDOHUnit(uint32_t streamID) +{ + // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-array-to-pointer-decay): clang-tidy is getting confused by assert() + assert(streamID <= std::numeric_limits<IncomingHTTP2Connection::StreamID>::max()); + // NOLINTNEXTLINE(*-narrowing-conversions): generic interface between DNS and DoH with different types + auto query = std::move(d_currentStreams.at(static_cast<IncomingHTTP2Connection::StreamID>(streamID))); + return std::make_unique<IncomingDoHCrossProtocolContext>(std::move(query), std::dynamic_pointer_cast<IncomingHTTP2Connection>(shared_from_this()), streamID); +} + +void IncomingHTTP2Connection::restoreDOHUnit(std::unique_ptr<DOHUnitInterface>&& unit) +{ + auto context = std::unique_ptr<IncomingDoHCrossProtocolContext>(dynamic_cast<IncomingDoHCrossProtocolContext*>(unit.release())); + if (context) { + d_currentStreams.at(context->d_streamID) = std::move(context->d_query); + } +} + +IncomingHTTP2Connection::IncomingHTTP2Connection(ConnectionInfo&& connectionInfo, TCPClientThreadData& threadData, const struct timeval& now) : + IncomingTCPConnectionState(std::move(connectionInfo), threadData, now) +{ + nghttp2_session_callbacks* cbs = nullptr; + if (nghttp2_session_callbacks_new(&cbs) != 0) { + throw std::runtime_error("Unable to create a callback object for a new incoming HTTP/2 session"); + } + std::unique_ptr<nghttp2_session_callbacks, void (*)(nghttp2_session_callbacks*)> callbacks(cbs, nghttp2_session_callbacks_del); + cbs = nullptr; + + nghttp2_session_callbacks_set_send_callback(callbacks.get(), send_callback); + nghttp2_session_callbacks_set_on_frame_recv_callback(callbacks.get(), on_frame_recv_callback); + nghttp2_session_callbacks_set_on_stream_close_callback(callbacks.get(), on_stream_close_callback); + nghttp2_session_callbacks_set_on_begin_headers_callback(callbacks.get(), on_begin_headers_callback); + nghttp2_session_callbacks_set_on_header_callback(callbacks.get(), on_header_callback); + nghttp2_session_callbacks_set_on_data_chunk_recv_callback(callbacks.get(), on_data_chunk_recv_callback); + nghttp2_session_callbacks_set_error_callback2(callbacks.get(), on_error_callback); + + nghttp2_session* sess = nullptr; + if (nghttp2_session_server_new(&sess, callbacks.get(), this) != 0) { + throw std::runtime_error("Coult not allocate a new incoming HTTP/2 session"); + } + + d_session = std::unique_ptr<nghttp2_session, decltype(&nghttp2_session_del)>(sess, nghttp2_session_del); + sess = nullptr; +} + +bool IncomingHTTP2Connection::checkALPN() +{ + constexpr std::array<uint8_t, 2> h2ALPN{'h', '2'}; + const auto protocols = d_handler.getNextProtocol(); + if (protocols.size() == h2ALPN.size() && memcmp(protocols.data(), h2ALPN.data(), h2ALPN.size()) == 0) { + return true; + } + + constexpr std::array<uint8_t, 8> http11ALPN{'h', 't', 't', 'p', '/', '1', '.', '1'}; + if (protocols.size() == http11ALPN.size() && memcmp(protocols.data(), http11ALPN.data(), http11ALPN.size()) == 0) { + ++d_ci.cs->dohFrontend->d_http1Stats.d_nbQueries; + } + + const std::string data("HTTP/1.1 400 Bad Request\r\nConnection: Close\r\n\r\n<html><body>This server implements RFC 8484 - DNS Queries over HTTP, and requires HTTP/2 in accordance with section 5.2 of the RFC.</body></html>\r\n"); + d_out.insert(d_out.end(), data.begin(), data.end()); + writeToSocket(false); + + vinfolog("DoH connection from %s expected ALPN value 'h2', got '%s'", d_ci.remote.toStringWithPort(), std::string(protocols.begin(), protocols.end())); + return false; +} + +void IncomingHTTP2Connection::handleConnectionReady() +{ + constexpr std::array<nghttp2_settings_entry, 1> settings{{{NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS, 100U}}}; + auto ret = nghttp2_submit_settings(d_session.get(), NGHTTP2_FLAG_NONE, settings.data(), settings.size()); + if (ret != 0) { + throw std::runtime_error("Fatal error: " + std::string(nghttp2_strerror(ret))); + } + d_needFlush = true; + ret = nghttp2_session_send(d_session.get()); + if (ret != 0) { + throw std::runtime_error("Fatal error: " + std::string(nghttp2_strerror(ret))); + } +} + +bool IncomingHTTP2Connection::hasPendingWrite() const +{ + return d_pendingWrite; +} + +IOState IncomingHTTP2Connection::handleHandshake(const struct timeval& now) +{ + auto iostate = d_handler.tryHandshake(); + if (iostate == IOState::Done) { + handleHandshakeDone(now); + if (d_handler.isTLS()) { + if (!checkALPN()) { + d_connectionDied = true; + stopIO(); + return iostate; + } + } + + if (d_ci.cs != nullptr && d_ci.cs->d_enableProxyProtocol && !isProxyPayloadOutsideTLS() && expectProxyProtocolFrom(d_ci.remote)) { + d_state = State::readingProxyProtocolHeader; + d_buffer.resize(s_proxyProtocolMinimumHeaderSize); + d_proxyProtocolNeed = s_proxyProtocolMinimumHeaderSize; + } + else { + d_state = State::waitingForQuery; + handleConnectionReady(); + } + } + return iostate; +} + +void IncomingHTTP2Connection::handleIO() +{ + IOState iostate = IOState::Done; + struct timeval now + { + }; + gettimeofday(&now, nullptr); + + try { + if (maxConnectionDurationReached(g_maxTCPConnectionDuration, now)) { + vinfolog("Terminating DoH connection from %s because it reached the maximum TCP connection duration", d_ci.remote.toStringWithPort()); + stopIO(); + d_connectionClosing = true; + return; + } + + if (d_state == State::starting) { + if (d_ci.cs != nullptr && d_ci.cs->dohFrontend != nullptr) { + ++d_ci.cs->dohFrontend->d_httpconnects; + } + if (d_ci.cs != nullptr && d_ci.cs->d_enableProxyProtocol && isProxyPayloadOutsideTLS() && expectProxyProtocolFrom(d_ci.remote)) { + d_state = State::readingProxyProtocolHeader; + d_buffer.resize(s_proxyProtocolMinimumHeaderSize); + d_proxyProtocolNeed = s_proxyProtocolMinimumHeaderSize; + } + else { + d_state = State::doingHandshake; + } + } + + if (d_state == State::doingHandshake) { + iostate = handleHandshake(now); + if (d_connectionDied) { + return; + } + } + + if (d_state == State::readingProxyProtocolHeader) { + auto status = handleProxyProtocolPayload(); + if (status == ProxyProtocolResult::Done) { + if (isProxyPayloadOutsideTLS()) { + d_state = State::doingHandshake; + iostate = handleHandshake(now); + if (d_connectionDied) { + return; + } + } + else { + d_currentPos = 0; + d_proxyProtocolNeed = 0; + d_buffer.clear(); + d_state = State::waitingForQuery; + handleConnectionReady(); + } + } + else if (status == ProxyProtocolResult::Error) { + d_connectionDied = true; + stopIO(); + return; + } + } + + if (active() && !d_connectionClosing && (d_state == State::waitingForQuery || d_state == State::idle)) { + do { + iostate = readHTTPData(); + } while (active() && !d_connectionClosing && iostate == IOState::Done); + } + + if (!active()) { + stopIO(); + return; + } + /* + So: + - if we have a pending write, we need to wait until the socket becomes writable + and then call handleWritableCallback + - if we have NeedWrite but no pending write, we need to wait until the socket + becomes writable but for handleReadableIOCallback + - if we have NeedRead, or nghttp2_session_want_read, wait until the socket + becomes readable and call handleReadableIOCallback + */ + if (hasPendingWrite()) { + updateIO(IOState::NeedWrite, handleWritableIOCallback); + } + else if (iostate == IOState::NeedWrite) { + updateIO(IOState::NeedWrite, handleReadableIOCallback); + } + else if (!d_connectionClosing) { + if (nghttp2_session_want_read(d_session.get()) != 0) { + updateIO(IOState::NeedRead, handleReadableIOCallback); + } + } + } + catch (const std::exception& e) { + vinfolog("Exception when processing IO for incoming DoH connection from %s: %s", d_ci.remote.toStringWithPort(), e.what()); + d_connectionDied = true; + stopIO(); + } +} + +void IncomingHTTP2Connection::writeToSocket(bool socketReady) +{ + try { + d_needFlush = false; + IOState newState = d_handler.tryWrite(d_out, d_outPos, d_out.size()); + + if (newState == IOState::Done) { + d_pendingWrite = false; + d_out.clear(); + d_outPos = 0; + if (active() && !d_connectionClosing) { + updateIO(IOState::NeedRead, handleReadableIOCallback); + } + else { + stopIO(); + } + } + else { + updateIO(newState, handleWritableIOCallback); + d_pendingWrite = true; + } + } + catch (const std::exception& e) { + vinfolog("Exception while trying to write (%s) to HTTP client connection to %s: %s", (socketReady ? "ready" : "send"), d_ci.remote.toStringWithPort(), e.what()); + handleIOError(); + } +} + +ssize_t IncomingHTTP2Connection::send_callback(nghttp2_session* session, const uint8_t* data, size_t length, int flags, void* user_data) +{ + auto* conn = static_cast<IncomingHTTP2Connection*>(user_data); + if (conn->d_connectionDied) { + return static_cast<ssize_t>(length); + } + // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic): nghttp2 API + conn->d_out.insert(conn->d_out.end(), data, data + length); + + if (conn->d_connectionClosing || conn->d_needFlush) { + conn->writeToSocket(false); + } + + return static_cast<ssize_t>(length); +} + +static const std::array<const std::string, static_cast<size_t>(NGHTTP2Headers::HeaderConstantIndexes::COUNT)> s_headerConstants{ + "200", + ":method", + "POST", + ":scheme", + "https", + ":authority", + "x-forwarded-for", + ":path", + "content-length", + ":status", + "location", + "accept", + "application/dns-message", + "cache-control", + "content-type", + "application/dns-message", + "user-agent", + "nghttp2-" NGHTTP2_VERSION "/dnsdist", + "x-forwarded-port", + "x-forwarded-proto", + "dns-over-udp", + "dns-over-tcp", + "dns-over-tls", + "dns-over-http", + "dns-over-https"}; + +static const std::string s_authorityHeaderName(":authority"); +static const std::string s_pathHeaderName(":path"); +static const std::string s_methodHeaderName(":method"); +static const std::string s_schemeHeaderName(":scheme"); +static const std::string s_xForwardedForHeaderName("x-forwarded-for"); + +void NGHTTP2Headers::addStaticHeader(std::vector<nghttp2_nv>& headers, NGHTTP2Headers::HeaderConstantIndexes nameKey, NGHTTP2Headers::HeaderConstantIndexes valueKey) +{ + const auto& name = s_headerConstants.at(static_cast<size_t>(nameKey)); + const auto& value = s_headerConstants.at(static_cast<size_t>(valueKey)); + + // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast,cppcoreguidelines-pro-type-reinterpret-cast): nghttp2 API + headers.push_back({const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(name.c_str())), const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(value.c_str())), name.size(), value.size(), NGHTTP2_NV_FLAG_NO_COPY_NAME | NGHTTP2_NV_FLAG_NO_COPY_VALUE}); +} + +void NGHTTP2Headers::addCustomDynamicHeader(std::vector<nghttp2_nv>& headers, const std::string& name, const std::string_view& value) +{ + // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast,cppcoreguidelines-pro-type-reinterpret-cast): nghttp2 API + headers.push_back({const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(name.data())), const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(value.data())), name.size(), value.size(), NGHTTP2_NV_FLAG_NO_COPY_NAME | NGHTTP2_NV_FLAG_NO_COPY_VALUE}); +} + +void NGHTTP2Headers::addDynamicHeader(std::vector<nghttp2_nv>& headers, NGHTTP2Headers::HeaderConstantIndexes nameKey, const std::string_view& value) +{ + const auto& name = s_headerConstants.at(static_cast<size_t>(nameKey)); + NGHTTP2Headers::addCustomDynamicHeader(headers, name, value); +} + +IOState IncomingHTTP2Connection::sendResponse(const struct timeval& now, TCPResponse&& response) +{ + // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-array-to-pointer-decay): clang-tidy is getting confused by assert() + assert(response.d_idstate.d_streamID != -1); + auto& context = d_currentStreams.at(response.d_idstate.d_streamID); + + uint32_t statusCode = 200U; + std::string contentType; + bool sendContentType = true; + auto& responseBuffer = context.d_buffer; + if (context.d_statusCode != 0) { + responseBuffer = std::move(context.d_response); + statusCode = context.d_statusCode; + contentType = std::move(context.d_contentTypeOut); + } + else { + responseBuffer = std::move(response.d_buffer); + } + + sendResponse(response.d_idstate.d_streamID, context, statusCode, d_ci.cs->dohFrontend->d_customResponseHeaders, contentType, sendContentType); + handleResponseSent(response); + + return hasPendingWrite() ? IOState::NeedWrite : IOState::Done; +} + +void IncomingHTTP2Connection::notifyIOError(const struct timeval& now, TCPResponse&& response) +{ + if (std::this_thread::get_id() != d_creatorThreadID) { + /* empty buffer will signal an IO error */ + response.d_buffer.clear(); + handleCrossProtocolResponse(now, std::move(response)); + return; + } + + // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-array-to-pointer-decay): clang-tidy is getting confused by assert() + assert(response.d_idstate.d_streamID != -1); + auto& context = d_currentStreams.at(response.d_idstate.d_streamID); + context.d_buffer = std::move(response.d_buffer); + sendResponse(response.d_idstate.d_streamID, context, 502, d_ci.cs->dohFrontend->d_customResponseHeaders); +} + +bool IncomingHTTP2Connection::sendResponse(IncomingHTTP2Connection::StreamID streamID, IncomingHTTP2Connection::PendingQuery& context, uint16_t responseCode, const HeadersMap& customResponseHeaders, const std::string& contentType, bool addContentType) +{ + /* if data_prd is not NULL, it provides data which will be sent in subsequent DATA frames. In this case, a method that allows request message bodies (https://tools.ietf.org/html/rfc7231#section-4) must be specified with :method key (e.g. POST). This function does not take ownership of the data_prd. The function copies the members of the data_prd. If data_prd is NULL, HEADERS have END_STREAM set. + */ + nghttp2_data_provider data_provider; + + data_provider.source.ptr = this; + data_provider.read_callback = [](nghttp2_session*, IncomingHTTP2Connection::StreamID stream_id, uint8_t* buf, size_t length, uint32_t* data_flags, nghttp2_data_source* source, void* cb_data) -> ssize_t { + auto* connection = static_cast<IncomingHTTP2Connection*>(cb_data); + auto& obj = connection->d_currentStreams.at(stream_id); + size_t toCopy = 0; + if (obj.d_queryPos < obj.d_buffer.size()) { + size_t remaining = obj.d_buffer.size() - obj.d_queryPos; + toCopy = length > remaining ? remaining : length; + memcpy(buf, &obj.d_buffer.at(obj.d_queryPos), toCopy); + obj.d_queryPos += toCopy; + } + + if (obj.d_queryPos >= obj.d_buffer.size()) { + *data_flags |= NGHTTP2_DATA_FLAG_EOF; + obj.d_buffer.clear(); + connection->d_needFlush = true; + } + return static_cast<ssize_t>(toCopy); + }; + + const auto& dohFrontend = d_ci.cs->dohFrontend; + auto& responseBody = context.d_buffer; + + std::vector<nghttp2_nv> headers; + std::string responseCodeStr; + std::string cacheControlValue; + std::string location; + /* remember that dynamic header values should be kept alive + until we have called nghttp2_submit_response(), at least */ + /* status, content-type, cache-control, content-length */ + headers.reserve(4); + + if (responseCode == 200) { + NGHTTP2Headers::addStaticHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::STATUS_NAME, NGHTTP2Headers::HeaderConstantIndexes::OK_200_VALUE); + ++dohFrontend->d_validresponses; + ++dohFrontend->d_http2Stats.d_nb200Responses; + + if (addContentType) { + if (contentType.empty()) { + NGHTTP2Headers::addStaticHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::CONTENT_TYPE_NAME, NGHTTP2Headers::HeaderConstantIndexes::CONTENT_TYPE_VALUE); + } + else { + NGHTTP2Headers::addDynamicHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::CONTENT_TYPE_NAME, contentType); + } + } + + if (dohFrontend->d_sendCacheControlHeaders && responseBody.size() > sizeof(dnsheader)) { + // NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast): API + uint32_t minTTL = getDNSPacketMinTTL(reinterpret_cast<const char*>(responseBody.data()), responseBody.size()); + if (minTTL != std::numeric_limits<uint32_t>::max()) { + cacheControlValue = "max-age=" + std::to_string(minTTL); + NGHTTP2Headers::addDynamicHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::CACHE_CONTROL_NAME, cacheControlValue); + } + } + } + else { + responseCodeStr = std::to_string(responseCode); + NGHTTP2Headers::addDynamicHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::STATUS_NAME, responseCodeStr); + + if (responseCode >= 300 && responseCode < 400) { + // NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast) + location = std::string(reinterpret_cast<const char*>(responseBody.data()), responseBody.size()); + NGHTTP2Headers::addDynamicHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::CONTENT_TYPE_NAME, "text/html; charset=utf-8"); + NGHTTP2Headers::addDynamicHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::LOCATION_NAME, location); + static const std::string s_redirectStart{"<!DOCTYPE html><TITLE>Moved</TITLE><P>The document has moved <A HREF=\""}; + static const std::string s_redirectEnd{"\">here</A>"}; + responseBody.reserve(s_redirectStart.size() + responseBody.size() + s_redirectEnd.size()); + responseBody.insert(responseBody.begin(), s_redirectStart.begin(), s_redirectStart.end()); + responseBody.insert(responseBody.end(), s_redirectEnd.begin(), s_redirectEnd.end()); + ++dohFrontend->d_redirectresponses; + } + else { + ++dohFrontend->d_errorresponses; + switch (responseCode) { + case 400: + ++dohFrontend->d_http2Stats.d_nb400Responses; + break; + case 403: + ++dohFrontend->d_http2Stats.d_nb403Responses; + break; + case 500: + ++dohFrontend->d_http2Stats.d_nb500Responses; + break; + case 502: + ++dohFrontend->d_http2Stats.d_nb502Responses; + break; + default: + ++dohFrontend->d_http2Stats.d_nbOtherResponses; + break; + } + + if (!responseBody.empty()) { + NGHTTP2Headers::addDynamicHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::CONTENT_TYPE_NAME, "text/plain; charset=utf-8"); + } + else { + static const std::string invalid{"invalid DNS query"}; + static const std::string notAllowed{"dns query not allowed"}; + static const std::string noDownstream{"no downstream server available"}; + static const std::string internalServerError{"Internal Server Error"}; + + switch (responseCode) { + case 400: + responseBody.insert(responseBody.begin(), invalid.begin(), invalid.end()); + break; + case 403: + responseBody.insert(responseBody.begin(), notAllowed.begin(), notAllowed.end()); + break; + case 502: + responseBody.insert(responseBody.begin(), noDownstream.begin(), noDownstream.end()); + break; + case 500: + /* fall-through */ + default: + responseBody.insert(responseBody.begin(), internalServerError.begin(), internalServerError.end()); + break; + } + } + } + } + + const std::string contentLength = std::to_string(responseBody.size()); + NGHTTP2Headers::addDynamicHeader(headers, NGHTTP2Headers::HeaderConstantIndexes::CONTENT_LENGTH_NAME, contentLength); + + for (const auto& [key, value] : customResponseHeaders) { + NGHTTP2Headers::addCustomDynamicHeader(headers, key, value); + } + + auto ret = nghttp2_submit_response(d_session.get(), streamID, headers.data(), headers.size(), &data_provider); + if (ret != 0) { + d_currentStreams.erase(streamID); + vinfolog("Error submitting HTTP response for stream %d: %s", streamID, nghttp2_strerror(ret)); + return false; + } + + ret = nghttp2_session_send(d_session.get()); + if (ret != 0) { + d_currentStreams.erase(streamID); + vinfolog("Error flushing HTTP response for stream %d: %s", streamID, nghttp2_strerror(ret)); + return false; + } + + return true; +} + +static void processForwardedForHeader(const std::unique_ptr<HeadersMap>& headers, ComboAddress& remote) +{ + if (!headers) { + return; + } + + auto headerIt = headers->find(s_xForwardedForHeaderName); + if (headerIt == headers->end()) { + return; + } + + std::string_view value = headerIt->second; + try { + auto pos = value.rfind(','); + if (pos != std::string_view::npos) { + ++pos; + for (; pos < value.size() && value[pos] == ' '; ++pos) { + } + + if (pos < value.size()) { + value = value.substr(pos); + } + } + auto newRemote = ComboAddress(std::string(value)); + remote = newRemote; + } + catch (const std::exception& e) { + vinfolog("Invalid X-Forwarded-For header ('%s') received from %s : %s", std::string(value), remote.toStringWithPort(), e.what()); + } + catch (const PDNSException& e) { + vinfolog("Invalid X-Forwarded-For header ('%s') received from %s : %s", std::string(value), remote.toStringWithPort(), e.reason); + } +} + +void IncomingHTTP2Connection::handleIncomingQuery(IncomingHTTP2Connection::PendingQuery&& query, IncomingHTTP2Connection::StreamID streamID) +{ + const auto handleImmediateResponse = [this, &query, streamID](uint16_t code, const std::string& reason, PacketBuffer&& response = PacketBuffer()) { + if (response.empty()) { + query.d_buffer.clear(); + query.d_buffer.insert(query.d_buffer.begin(), reason.begin(), reason.end()); + } + else { + query.d_buffer = std::move(response); + } + vinfolog("Sending an immediate %d response to incoming DoH query: %s", code, reason); + sendResponse(streamID, query, code, d_ci.cs->dohFrontend->d_customResponseHeaders); + }; + + if (query.d_method == PendingQuery::Method::Unknown || query.d_method == PendingQuery::Method::Unsupported) { + handleImmediateResponse(400, "DoH query not allowed because of unsupported HTTP method"); + return; + } + + ++d_ci.cs->dohFrontend->d_http2Stats.d_nbQueries; + + if (d_ci.cs->dohFrontend->d_trustForwardedForHeader) { + processForwardedForHeader(query.d_headers, d_proxiedRemote); + + /* second ACL lookup based on the updated address */ + auto& holders = d_threadData.holders; + if (!holders.acl->match(d_proxiedRemote)) { + ++dnsdist::metrics::g_stats.aclDrops; + vinfolog("Query from %s (%s) (DoH) dropped because of ACL", d_ci.remote.toStringWithPort(), d_proxiedRemote.toStringWithPort()); + handleImmediateResponse(403, "DoH query not allowed because of ACL"); + return; + } + + if (!d_ci.cs->dohFrontend->d_keepIncomingHeaders) { + query.d_headers.reset(); + } + } + + if (d_ci.cs->dohFrontend->d_exactPathMatching) { + if (d_ci.cs->dohFrontend->d_urls.count(query.d_path) == 0) { + handleImmediateResponse(404, "there is no endpoint configured for this path"); + return; + } + } + else { + bool found = false; + for (const auto& path : d_ci.cs->dohFrontend->d_urls) { + if (boost::starts_with(query.d_path, path)) { + found = true; + break; + } + } + if (!found) { + handleImmediateResponse(404, "there is no endpoint configured for this path"); + return; + } + } + + /* the responses map can be updated at runtime, so we need to take a copy of + the shared pointer, increasing the reference counter */ + auto responsesMap = d_ci.cs->dohFrontend->d_responsesMap; + if (responsesMap) { + for (const auto& entry : *responsesMap) { + if (entry->matches(query.d_path)) { + const auto& customHeaders = entry->getHeaders(); + query.d_buffer = entry->getContent(); + if (entry->getStatusCode() >= 400 && !query.d_buffer.empty()) { + // legacy trailing 0 from the h2o era + query.d_buffer.pop_back(); + } + + sendResponse(streamID, query, entry->getStatusCode(), customHeaders ? *customHeaders : d_ci.cs->dohFrontend->d_customResponseHeaders, std::string(), false); + return; + } + } + } + + if (query.d_buffer.empty() && query.d_method == PendingQuery::Method::Get && !query.d_queryString.empty()) { + auto payload = dnsdist::doh::getPayloadFromPath(query.d_queryString); + if (payload) { + query.d_buffer = std::move(*payload); + } + else { + ++d_ci.cs->dohFrontend->d_badrequests; + handleImmediateResponse(400, "DoH unable to decode BASE64-URL"); + return; + } + } + + if (query.d_method == PendingQuery::Method::Get) { + ++d_ci.cs->dohFrontend->d_getqueries; + } + else if (query.d_method == PendingQuery::Method::Post) { + ++d_ci.cs->dohFrontend->d_postqueries; + } + + try { + struct timeval now + { + }; + gettimeofday(&now, nullptr); + auto processingResult = handleQuery(std::move(query.d_buffer), now, streamID); + + switch (processingResult) { + case QueryProcessingResult::TooSmall: + handleImmediateResponse(400, "DoH non-compliant query"); + break; + case QueryProcessingResult::InvalidHeaders: + handleImmediateResponse(400, "DoH invalid headers"); + break; + case QueryProcessingResult::Dropped: + handleImmediateResponse(403, "DoH dropped query"); + break; + case QueryProcessingResult::NoBackend: + handleImmediateResponse(502, "DoH no backend available"); + return; + case QueryProcessingResult::Forwarded: + case QueryProcessingResult::Asynchronous: + case QueryProcessingResult::SelfAnswered: + break; + } + } + catch (const std::exception& e) { + vinfolog("Exception while processing DoH query: %s", e.what()); + handleImmediateResponse(400, "DoH non-compliant query"); + return; + } +} + +int IncomingHTTP2Connection::on_frame_recv_callback(nghttp2_session* session, const nghttp2_frame* frame, void* user_data) +{ + auto* conn = static_cast<IncomingHTTP2Connection*>(user_data); + /* is this the last frame for this stream? */ + if ((frame->hd.type == NGHTTP2_HEADERS || frame->hd.type == NGHTTP2_DATA) && (frame->hd.flags & NGHTTP2_FLAG_END_STREAM) != 0) { + auto streamID = frame->hd.stream_id; + auto stream = conn->d_currentStreams.find(streamID); + if (stream != conn->d_currentStreams.end()) { + conn->handleIncomingQuery(std::move(stream->second), streamID); + } + else { + vinfolog("Stream %d NOT FOUND", streamID); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } + } + + return 0; +} + +int IncomingHTTP2Connection::on_stream_close_callback(nghttp2_session* session, IncomingHTTP2Connection::StreamID stream_id, uint32_t error_code, void* user_data) +{ + auto* conn = static_cast<IncomingHTTP2Connection*>(user_data); + + conn->d_currentStreams.erase(stream_id); + return 0; +} + +int IncomingHTTP2Connection::on_begin_headers_callback(nghttp2_session* session, const nghttp2_frame* frame, void* user_data) +{ + if (frame->hd.type != NGHTTP2_HEADERS || frame->headers.cat != NGHTTP2_HCAT_REQUEST) { + return 0; + } + + auto* conn = static_cast<IncomingHTTP2Connection*>(user_data); + auto insertPair = conn->d_currentStreams.emplace(frame->hd.stream_id, PendingQuery()); + if (!insertPair.second) { + /* there is a stream ID collision, something is very wrong! */ + vinfolog("Stream ID collision (%d) on connection from %d", frame->hd.stream_id, conn->d_ci.remote.toStringWithPort()); + conn->d_connectionClosing = true; + conn->d_needFlush = true; + nghttp2_session_terminate_session(conn->d_session.get(), NGHTTP2_NO_ERROR); + auto ret = nghttp2_session_send(conn->d_session.get()); + if (ret != 0) { + vinfolog("Error flushing HTTP response for stream %d from %s: %s", frame->hd.stream_id, conn->d_ci.remote.toStringWithPort(), nghttp2_strerror(ret)); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } + + return 0; + } + + return 0; +} + +static std::string::size_type getLengthOfPathWithoutParameters(const std::string_view& path) +{ + auto pos = path.find('?'); + if (pos == string::npos) { + return path.size(); + } + + return pos; +} + +int IncomingHTTP2Connection::on_header_callback(nghttp2_session* session, const nghttp2_frame* frame, const uint8_t* name, size_t nameLen, const uint8_t* value, size_t valuelen, uint8_t flags, void* user_data) +{ + auto* conn = static_cast<IncomingHTTP2Connection*>(user_data); + + if (frame->hd.type == NGHTTP2_HEADERS && frame->headers.cat == NGHTTP2_HCAT_REQUEST) { + if (nghttp2_check_header_name(name, nameLen) == 0) { + vinfolog("Invalid header name"); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } + +#if HAVE_NGHTTP2_CHECK_HEADER_VALUE_RFC9113 + if (nghttp2_check_header_value_rfc9113(value, valuelen) == 0) { + vinfolog("Invalid header value"); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } +#endif /* HAVE_NGHTTP2_CHECK_HEADER_VALUE_RFC9113 */ + + auto headerMatches = [name, nameLen](const std::string& expected) -> bool { + return nameLen == expected.size() && memcmp(name, expected.data(), expected.size()) == 0; + }; + + auto stream = conn->d_currentStreams.find(frame->hd.stream_id); + if (stream == conn->d_currentStreams.end()) { + vinfolog("Unable to match the stream ID %d to a known one!", frame->hd.stream_id); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } + auto& query = stream->second; + // NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast): nghttp2 API + auto valueView = std::string_view(reinterpret_cast<const char*>(value), valuelen); + if (headerMatches(s_pathHeaderName)) { +#if HAVE_NGHTTP2_CHECK_PATH + if (nghttp2_check_path(value, valuelen) == 0) { + vinfolog("Invalid path value"); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } +#endif /* HAVE_NGHTTP2_CHECK_PATH */ + + auto pathLen = getLengthOfPathWithoutParameters(valueView); + query.d_path = valueView.substr(0, pathLen); + if (pathLen < valueView.size()) { + query.d_queryString = valueView.substr(pathLen); + } + } + else if (headerMatches(s_authorityHeaderName)) { + query.d_host = valueView; + } + else if (headerMatches(s_schemeHeaderName)) { + query.d_scheme = valueView; + } + else if (headerMatches(s_methodHeaderName)) { +#if HAVE_NGHTTP2_CHECK_METHOD + if (nghttp2_check_method(value, valuelen) == 0) { + vinfolog("Invalid method value"); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } +#endif /* HAVE_NGHTTP2_CHECK_METHOD */ + + if (valueView == "GET") { + query.d_method = PendingQuery::Method::Get; + } + else if (valueView == "POST") { + query.d_method = PendingQuery::Method::Post; + } + else { + query.d_method = PendingQuery::Method::Unsupported; + vinfolog("Unsupported method value"); + return 0; + } + } + + if (conn->d_ci.cs->dohFrontend->d_keepIncomingHeaders || (conn->d_ci.cs->dohFrontend->d_trustForwardedForHeader && headerMatches(s_xForwardedForHeaderName))) { + if (!query.d_headers) { + query.d_headers = std::make_unique<HeadersMap>(); + } + // NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast): nghttp2 API + query.d_headers->insert({std::string(reinterpret_cast<const char*>(name), nameLen), std::string(valueView)}); + } + } + return 0; +} + +int IncomingHTTP2Connection::on_data_chunk_recv_callback(nghttp2_session* session, uint8_t flags, IncomingHTTP2Connection::StreamID stream_id, const uint8_t* data, size_t len, void* user_data) +{ + auto* conn = static_cast<IncomingHTTP2Connection*>(user_data); + auto stream = conn->d_currentStreams.find(stream_id); + if (stream == conn->d_currentStreams.end()) { + vinfolog("Unable to match the stream ID %d to a known one!", stream_id); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } + if (len > std::numeric_limits<uint16_t>::max() || (std::numeric_limits<uint16_t>::max() - stream->second.d_buffer.size()) < len) { + vinfolog("Data frame of size %d is too large for a DNS query (we already have %d)", len, stream->second.d_buffer.size()); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } + + // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic): nghttp2 API + stream->second.d_buffer.insert(stream->second.d_buffer.end(), data, data + len); + + return 0; +} + +int IncomingHTTP2Connection::on_error_callback(nghttp2_session* session, int lib_error_code, const char* msg, size_t len, void* user_data) +{ + auto* conn = static_cast<IncomingHTTP2Connection*>(user_data); + + vinfolog("Error in HTTP/2 connection from %d: %s", conn->d_ci.remote.toStringWithPort(), std::string(msg, len)); + conn->d_connectionClosing = true; + conn->d_needFlush = true; + nghttp2_session_terminate_session(conn->d_session.get(), NGHTTP2_NO_ERROR); + auto ret = nghttp2_session_send(conn->d_session.get()); + if (ret != 0) { + vinfolog("Error flushing HTTP response on connection from %s: %s", conn->d_ci.remote.toStringWithPort(), nghttp2_strerror(ret)); + return NGHTTP2_ERR_CALLBACK_FAILURE; + } + + return 0; +} + +IOState IncomingHTTP2Connection::readHTTPData() +{ + IOState newState = IOState::Done; + size_t got = 0; + if (d_in.size() < s_initialReceiveBufferSize) { + d_in.resize(std::max(s_initialReceiveBufferSize, d_in.capacity())); + } + try { + newState = d_handler.tryRead(d_in, got, d_in.size(), true); + d_in.resize(got); + + if (got > 0) { + /* we got something */ + auto readlen = nghttp2_session_mem_recv(d_session.get(), d_in.data(), d_in.size()); + /* as long as we don't require a pause by returning nghttp2_error.NGHTTP2_ERR_PAUSE from a CB, + all data should be consumed before returning */ + if (readlen < 0 || static_cast<size_t>(readlen) < d_in.size()) { + throw std::runtime_error("Fatal error while passing received data to nghttp2: " + std::string(nghttp2_strerror((int)readlen))); + } + + nghttp2_session_send(d_session.get()); + } + } + catch (const std::exception& e) { + vinfolog("Exception while trying to read from HTTP client connection to %s: %s", d_ci.remote.toStringWithPort(), e.what()); + handleIOError(); + return IOState::Done; + } + return newState; +} + +void IncomingHTTP2Connection::handleReadableIOCallback([[maybe_unused]] int descriptor, FDMultiplexer::funcparam_t& param) +{ + auto conn = boost::any_cast<std::shared_ptr<IncomingHTTP2Connection>>(param); + conn->handleIO(); +} + +void IncomingHTTP2Connection::handleWritableIOCallback([[maybe_unused]] int descriptor, FDMultiplexer::funcparam_t& param) +{ + auto conn = boost::any_cast<std::shared_ptr<IncomingHTTP2Connection>>(param); + conn->writeToSocket(true); +} + +void IncomingHTTP2Connection::stopIO() +{ + if (d_ioState) { + d_ioState->reset(); + } +} + +uint32_t IncomingHTTP2Connection::getConcurrentStreamsCount() const +{ + return d_currentStreams.size(); +} + +boost::optional<struct timeval> IncomingHTTP2Connection::getIdleClientReadTTD(struct timeval now) const +{ + auto idleTimeout = d_ci.cs->dohFrontend->d_idleTimeout; + if (g_maxTCPConnectionDuration == 0 && idleTimeout == 0) { + return boost::none; + } + + if (g_maxTCPConnectionDuration > 0) { + auto elapsed = now.tv_sec - d_connectionStartTime.tv_sec; + if (elapsed < 0 || (static_cast<size_t>(elapsed) >= g_maxTCPConnectionDuration)) { + return now; + } + auto remaining = g_maxTCPConnectionDuration - elapsed; + if (idleTimeout == 0 || remaining <= static_cast<size_t>(idleTimeout)) { + now.tv_sec += static_cast<time_t>(remaining); + return now; + } + } + + now.tv_sec += idleTimeout; + return now; +} + +void IncomingHTTP2Connection::updateIO(IOState newState, const FDMultiplexer::callbackfunc_t& callback) +{ + boost::optional<struct timeval> ttd{boost::none}; + + auto shared = std::dynamic_pointer_cast<IncomingHTTP2Connection>(shared_from_this()); + if (!shared || !d_ioState) { + return; + } + + timeval now{}; + gettimeofday(&now, nullptr); + + if (newState == IOState::NeedRead) { + /* use the idle TTL if the handshake has been completed (and proxy protocol payload received, if any), + and we have processed at least one query, otherwise we use the shorter read TTL */ + if ((d_state == State::waitingForQuery || d_state == State::idle) && (d_queriesCount > 0 || d_currentQueriesCount > 0)) { + ttd = getIdleClientReadTTD(now); + } + else { + ttd = getClientReadTTD(now); + } + d_ioState->update(newState, callback, shared, ttd); + } + else if (newState == IOState::NeedWrite) { + ttd = getClientWriteTTD(now); + d_ioState->update(newState, callback, shared, ttd); + } +} + +void IncomingHTTP2Connection::handleIOError() +{ + d_connectionDied = true; + d_out.clear(); + d_outPos = 0; + nghttp2_session_terminate_session(d_session.get(), NGHTTP2_PROTOCOL_ERROR); + d_currentStreams.clear(); + stopIO(); +} + +bool IncomingHTTP2Connection::active() const +{ + return !d_connectionDied && d_ioState != nullptr; +} + +#endif /* HAVE_DNS_OVER_HTTPS && HAVE_NGHTTP2 */ |