Experimental QUIC support for nginx ----------------------------------- 1. Introduction 2. Installing 3. Configuration 4. Clients 5. Troubleshooting 6. Contributing 7. Links 1. Introduction This is an experimental QUIC [1] / HTTP/3 [2] support for nginx. The code is developed in a separate "quic" branch available at https://hg.nginx.org/nginx-quic. Currently it is based on nginx mainline 1.21.x. We merge new nginx releases into this branch regularly. The project code base is under the same BSD license as nginx. The code is currently at a beta level of quality and should not be used in production. We are working on improving HTTP/3 support with the goal of integrating it to the main NGINX codebase. Expect frequent updates of this code and don't rely on it for whatever purpose. We'll be grateful for any feedback and code submissions however we don't bear any responsibilities for any issues with this code. You can always contact us via nginx-devel mailing list [3]. What works now: Currently we support IETF-QUIC draft-29 through final RFC documents. Earlier drafts are NOT supported as they have incompatible wire format. nginx should be able to respond to HTTP/3 requests over QUIC and it should be possible to upload and download big files without errors. + The handshake completes successfully + One endpoint can update keys and its peer responds correctly + 0-RTT data is being received and acted on + Connection is established using TLS Resume Ticket + A handshake that includes a Retry packet completes successfully + Stream data is being exchanged and ACK'ed + An H3 transaction succeeded + One or both endpoints insert entries into dynamic table and subsequently reference them from header blocks + Version Negotiation packet is sent to client with unknown version + Lost packets are detected and retransmitted properly + Clients may migrate to new address Not (yet) supported features: - Explicit Congestion Notification (ECN) as specified in quic-recovery [5] - A connection with the spin bit succeeds and the bit is spinning - Structured Logging Since the code is experimental and still under development, a lot of things may not work as expected, for example: - Flow control mechanism is basic and intended to avoid CPU hog and make simple interactions possible - Not all protocol requirements are strictly followed; some of checks are omitted for the sake of simplicity of initial implementation 2. Installing You will need a BoringSSL [4] library that provides QUIC support $ hg clone -b quic https://hg.nginx.org/nginx-quic $ cd nginx-quic $ ./auto/configure --with-debug --with-http_v3_module \ --with-cc-opt="-I../boringssl/include" \ --with-ld-opt="-L../boringssl/build/ssl \ -L../boringssl/build/crypto" $ make When configuring nginx, you can enable QUIC and HTTP/3 using the following new configuration options: --with-http_v3_module - enable QUIC and HTTP/3 --with-stream_quic_module - enable QUIC in Stream 3. Configuration The HTTP "listen" directive got a new option "http3" which enables HTTP/3 over QUIC on the specified port. The Stream "listen" directive got a new option "quic" which enables QUIC as client transport protocol instead of TCP or plain UDP. Along with "http3" or "quic", you also have to specify "reuseport" option [6] to make it work properly with multiple workers. To enable address validation: quic_retry on; To enable 0-RTT: ssl_early_data on; Make sure that TLS 1.3 is configured which is required for QUIC: ssl_protocols TLSv1.3; To enable GSO (Generic Segmentation Offloading): quic_gso on; To limit maximum packet size: quic_mtu ; To set host key for various tokens: quic_host_key ; By default this Linux-specific optimization [8] is disabled. Enable if your network interface is configured to support GSO. A number of directives were added that configure HTTP/3: http3_stream_buffer_size http3_max_concurrent_pushes http3_max_concurrent_streams http3_push http3_push_preload http3_hq (requires NGX_HTTP_V3_HQ macro) In http, an additional variable is available: $http3. The value of $http3 is "h3" for HTTP/3 connections, "hq" for hq connections, or an empty string otherwise. In stream, an additional variable is available: $quic. The value of $quic is "quic" if QUIC connection is used, or an empty string otherwise. Example configuration: http { log_format quic '$remote_addr - $remote_user [$time_local] ' '"$request" $status $body_bytes_sent ' '"$http_referer" "$http_user_agent" "$http3"'; access_log logs/access.log quic; server { # for better compatibility it's recommended # to use the same port for quic and https listen 8443 http3 reuseport; listen 8443 ssl; ssl_certificate certs/example.com.crt; ssl_certificate_key certs/example.com.key; ssl_protocols TLSv1.3; location / { # required for browsers to direct them into quic port add_header Alt-Svc 'h3=":8443"; ma=86400'; } } } 4. Clients * Browsers Known to work: Firefox 80+ and Chrome 85+ (QUIC draft 29+) Beware of strange issues: sometimes browser may decide to ignore QUIC Cache clearing/restart might help. Always check access.log and error.log to make sure you are using HTTP/3 and not TCP https. + to enable QUIC in Firefox, set the following in 'about:config': network.http.http3.enabled = true + to enable QUIC in Chrome, enable it on command line and force it on your site: $ ./chrome --enable-quic --quic-version=h3-29 \ --origin-to-force-quic-on=example.com:8443 * Console clients Known to work: ngtcp2, firefox's neqo and chromium's console clients: $ examples/client 127.0.0.1 8443 https://example.com:8443/index.html $ ./neqo-client https://127.0.0.1:8443/ $ chromium-build/out/my_build/quic_client http://example.com:8443 \ --quic_version=h3-29 \ --allow_unknown_root_cert \ --disable_certificate_verification If you've got it right, in the access log you should see something like: 127.0.0.1 - - [24/Apr/2020:11:27:29 +0300] "GET / HTTP/3" 200 805 "-" "nghttp3/ngtcp2 client" "quic" 5. Troubleshooting Here are some tips that may help you to identify problems: + Ensure you are building with proper SSL library that supports QUIC + Ensure you are using the proper SSL library in runtime (`nginx -V` will show you what you are using) + Ensure your client is actually sending QUIC requests (see "Clients" section about browsers and cache) We recommend to start with simple console client like ngtcp2 to ensure you've got server configured properly before trying with real browsers that may be very picky with certificates, for example. + Build nginx with debug support [7] and check your debug log. It should contain all details about connection and why it failed. All related messages contain "quic " prefix and can be easily filtered out. + If you want to investigate deeper, you may want to enable additional debugging in src/event/quic/ngx_event_quic_connection.h: #define NGX_QUIC_DEBUG_PACKETS #define NGX_QUIC_DEBUG_FRAMES #define NGX_QUIC_DEBUG_ALLOC #define NGX_QUIC_DEBUG_CRYPTO 6. Contributing If you are willing to contribute, please refer to http://nginx.org/en/docs/contributing_changes.html 7. Links [1] https://datatracker.ietf.org/doc/html/rfc9000 [2] https://datatracker.ietf.org/doc/html/draft-ietf-quic-http [3] https://mailman.nginx.org/mailman/listinfo/nginx-devel [4] https://boringssl.googlesource.com/boringssl/ [5] https://datatracker.ietf.org/doc/html/rfc9002 [6] https://nginx.org/en/docs/http/ngx_http_core_module.html#listen [7] https://nginx.org/en/docs/debugging_log.html [8] http://vger.kernel.org/lpc_net2018_talks/willemdebruijn-lpc2018-udpgso-paper-DRAFT-1.pdf