HTTP/3 Explained - the online free book describing the protocols involved.
quicwg.org - home of the official protocol drafts
QUIC libraries we are using:
quiche - EXPERIMENTAL
OpenSSL 3.2+ QUIC - EXPERIMENTAL
msh3 (with msquic) - EXPERIMENTAL
HTTP/3 support in curl is considered EXPERIMENTAL until further notice when built to use quiche or msh3. Only the ngtcp2 backend is not experimental.
Further development and tweaking of the HTTP/3 support in curl happens in the master branch using pull-requests, just like ordinary changes.
To fix before we remove the experimental label:
Building curl with ngtcp2 involves 3 components: ngtcp2
itself, nghttp3
and a QUIC supporting TLS library. The supported TLS libraries are covered below.
ngtcp2
: v1.2.0nghttp3
: v1.1.0OpenSSL does not offer the required APIs for building a QUIC client. You need to use a TLS library that has such APIs and that works with ngtcp2.
Build quictls
% git clone --depth 1 -b openssl-3.1.4+quic https://github.com/quictls/openssl
% cd openssl
% ./config enable-tls1_3 --prefix=<somewhere1>
% make
% make install
Build nghttp3
% cd ..
% git clone -b v1.1.0 https://github.com/ngtcp2/nghttp3
% cd nghttp3
% git submodule update --init
% autoreconf -fi
% ./configure --prefix=<somewhere2> --enable-lib-only
% make
% make install
Build ngtcp2
% cd ..
% git clone -b v1.2.0 https://github.com/ngtcp2/ngtcp2
% cd ngtcp2
% autoreconf -fi
% ./configure PKG_CONFIG_PATH=<somewhere1>/lib/pkgconfig:<somewhere2>/lib/pkgconfig LDFLAGS="-Wl,-rpath,<somewhere1>/lib" --prefix=<somewhere3> --enable-lib-only
% make
% make install
Build curl
% cd ..
% git clone https://github.com/curl/curl
% cd curl
% autoreconf -fi
% LDFLAGS="-Wl,-rpath,<somewhere1>/lib" ./configure --with-openssl=<somewhere1> --with-nghttp3=<somewhere2> --with-ngtcp2=<somewhere3>
% make
% make install
For OpenSSL 3.0.0 or later builds on Linux for x86_64 architecture, substitute all occurrences of "/lib" with "/lib64"
Build GnuTLS
% git clone --depth 1 https://gitlab.com/gnutls/gnutls.git
% cd gnutls
% ./bootstrap
% ./configure --prefix=<somewhere1>
% make
% make install
Build nghttp3
% cd ..
% git clone -b v1.1.0 https://github.com/ngtcp2/nghttp3
% cd nghttp3
% git submodule update --init
% autoreconf -fi
% ./configure --prefix=<somewhere2> --enable-lib-only
% make
% make install
Build ngtcp2
% cd ..
% git clone -b v1.2.0 https://github.com/ngtcp2/ngtcp2
% cd ngtcp2
% autoreconf -fi
% ./configure PKG_CONFIG_PATH=<somewhere1>/lib/pkgconfig:<somewhere2>/lib/pkgconfig LDFLAGS="-Wl,-rpath,<somewhere1>/lib" --prefix=<somewhere3> --enable-lib-only --with-gnutls
% make
% make install
Build curl
% cd ..
% git clone https://github.com/curl/curl
% cd curl
% autoreconf -fi
% ./configure --with-gnutls=<somewhere1> --with-nghttp3=<somewhere2> --with-ngtcp2=<somewhere3>
% make
% make install
Build wolfSSL
% git clone https://github.com/wolfSSL/wolfssl.git
% cd wolfssl
% autoreconf -fi
% ./configure --prefix=<somewhere1> --enable-quic --enable-session-ticket --enable-earlydata --enable-psk --enable-harden --enable-altcertchains
% make
% make install
Build nghttp3
% cd ..
% git clone -b v1.1.0 https://github.com/ngtcp2/nghttp3
% cd nghttp3
% git submodule update --init
% autoreconf -fi
% ./configure --prefix=<somewhere2> --enable-lib-only
% make
% make install
Build ngtcp2
% cd ..
% git clone -b v1.2.0 https://github.com/ngtcp2/ngtcp2
% cd ngtcp2
% autoreconf -fi
% ./configure PKG_CONFIG_PATH=<somewhere1>/lib/pkgconfig:<somewhere2>/lib/pkgconfig LDFLAGS="-Wl,-rpath,<somewhere1>/lib" --prefix=<somewhere3> --enable-lib-only --with-wolfssl
% make
% make install
Build curl
% cd ..
% git clone https://github.com/curl/curl
% cd curl
% autoreconf -fi
% ./configure --with-wolfssl=<somewhere1> --with-nghttp3=<somewhere2> --with-ngtcp2=<somewhere3>
% make
% make install
quiche support is EXPERIMENTAL
Since the quiche build manages its dependencies, curl can be built against the latest version. You are probably able to build against their main branch, but in case of problems, we recommend their latest release tag.
Build quiche and BoringSSL:
% git clone --recursive -b 0.20.0 https://github.com/cloudflare/quiche
% cd quiche
% cargo build --package quiche --release --features ffi,pkg-config-meta,qlog
% mkdir quiche/deps/boringssl/src/lib
% ln -vnf $(find target/release -name libcrypto.a -o -name libssl.a) quiche/deps/boringssl/src/lib/
Build curl:
% cd ..
% git clone https://github.com/curl/curl
% cd curl
% autoreconf -fi
% ./configure LDFLAGS="-Wl,-rpath,$PWD/../quiche/target/release" --with-openssl=$PWD/../quiche/quiche/deps/boringssl/src --with-quiche=$PWD/../quiche/target/release
% make
% make install
If make install
results in Permission denied
error, you need to prepend
it with sudo
.
QUIC support is EXPERIMENTAL
Build OpenSSL 3.2.0
% cd ..
% git clone -b openssl-3.2.0 https://github.com/openssl/openssl
% cd openssl
% ./config enable-tls1_3 --prefix=<somewhere> --libdir=<somewhere>/lib
% make
% make install
Build nghttp3
% cd ..
% git clone -b v1.1.0 https://github.com/ngtcp2/nghttp3
% cd nghttp3
% git submodule update --init
% autoreconf -fi
% ./configure --prefix=<somewhere2> --enable-lib-only
% make
% make install
Build curl:
% cd ..
% git clone https://github.com/curl/curl
% cd curl
% autoreconf -fi
% LDFLAGS="-Wl,-rpath,<somewhere>/lib" ./configure --with-openssl=<somewhere> --with-openssl-quic --with-nghttp3=<somewhere2>
% make
% make install
You can build curl with cmake:
% cd ..
% git clone https://github.com/curl/curl
% cd curl
% cmake . -B build -DCURL_USE_OPENSSL=ON -DUSE_OPENSSL_QUIC=ON
% cmake --build build
% cmake --install build
If make install
results in Permission denied
error, you need to prepend
it with sudo
.
Note: The msquic HTTP/3 backend is immature and is not properly functional one as of September 2023. Feel free to help us test it and improve it, but there is no point in filing bugs about it just yet.
msh3 support is EXPERIMENTAL
Build msh3:
% git clone -b v0.6.0 --depth 1 --recursive https://github.com/nibanks/msh3
% cd msh3 && mkdir build && cd build
% cmake -G 'Unix Makefiles' -DCMAKE_BUILD_TYPE=RelWithDebInfo ..
% cmake --build .
% cmake --install .
Build curl:
% git clone https://github.com/curl/curl
% cd curl
% autoreconf -fi
% ./configure LDFLAGS="-Wl,-rpath,/usr/local/lib" --with-msh3=/usr/local --with-openssl
% make
% make install
Run from /usr/local/bin/curl
.
Build msh3:
% git clone -b v0.6.0 --depth 1 --recursive https://github.com/nibanks/msh3
% cd msh3 && mkdir build && cd build
% cmake -G 'Visual Studio 17 2022' -DCMAKE_BUILD_TYPE=RelWithDebInfo ..
% cmake --build . --config Release
% cmake --install . --config Release
Note - On Windows, Schannel is used for TLS support by default. If you
with to use (the quictls fork of) OpenSSL, specify the -DQUIC_TLS=openssl
option to the generate command above. Also note that OpenSSL brings with it an
additional set of build dependencies not specified here.
Build curl (in Visual Studio Command prompt):
% git clone https://github.com/curl/curl
% cd curl/winbuild
% nmake /f Makefile.vc mode=dll WITH_MSH3=dll MSH3_PATH="C:/Program Files/msh3" MACHINE=x64
Note - If you encounter a build error with tool_hugehelp.c
being
missing, rename tool_hugehelp.c.cvs
in the same directory to
tool_hugehelp.c
and then run nmake
again.
Run in the C:/Program Files/msh3/lib
directory, copy curl.exe
to that
directory, or copy msquic.dll
and msh3.dll
from that directory to the
curl.exe
directory. For example:
% C:\Program Files\msh3\lib> F:\curl\builds\libcurl-vc-x64-release-dll-ipv6-sspi-schannel-msh3\bin\curl.exe --http3 https://curl.se/
--http3
Use only HTTP/3:
curl --http3-only https://example.org:4433/
Use HTTP/3 with fallback to HTTP/2 or HTTP/1.1 (see "HTTPS eyeballing" below):
curl --http3 https://example.org:4433/
Upgrade via Alt-Svc:
curl --alt-svc altsvc.cache https://curl.se/
See this list of public HTTP/3 servers
With option --http3
curl attempts earlier HTTP versions as well should the
connect attempt via HTTP/3 not succeed "fast enough". This strategy is similar
to IPv4/6 happy eyeballing where the alternate address family is used in
parallel after a short delay.
The IPv4/6 eyeballing has a default of 200ms and you may override that via
--happy-eyeballs-timeout-ms value
. Since HTTP/3 is still relatively new, we
decided to use this timeout also for the HTTP eyeballing - with a slight
twist.
The happy-eyeballs-timeout-ms
value is the hard timeout, meaning after
that time expired, a TLS connection is opened in addition to negotiate HTTP/2
or HTTP/1.1. At half of that value - currently - is the soft timeout. The
soft timeout fires, when there has been no data at all seen from the
server on the HTTP/3 connection.
So, without you specifying anything, the hard timeout is 200ms and the soft is 100ms:
The whole transfer only fails, when both QUIC and TLS+TCP fail to handshake or time out.
Note that all this happens in addition to IP version happy eyeballing. If the name resolution for the server gives more than one IP address, curl tries all those until one succeeds - just as with all other protocols. If those IP addresses contain both IPv6 and IPv4, those attempts happen, delayed, in parallel (the actual eyeballing).
Check out the list of known HTTP3 bugs.
This is not advice on how to run anything in production. This is for development and experimenting.
An existing local HTTP/1.1 server that hosts files. Preferably also a few huge
ones. You can easily create huge local files like truncate -s=8G 8GB
- they
are huge but do not occupy that much space on disk since they are just big
holes.
In a Debian setup you can install apache2. It runs on port 80 and has a
document root in /var/www/html
. Download the 8GB file from apache with curl
localhost/8GB -o dev/null
In this description we setup and run an HTTP/3 reverse-proxy in front of the HTTP/1 server.
You can select either or both of these server solutions.
Get, build and install quictls, nghttp3 and ngtcp2 as described above.
Get, build and install nghttp2:
git clone https://github.com/nghttp2/nghttp2.git
cd nghttp2
autoreconf -fi
PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/home/daniel/build-quictls/lib/pkgconfig:/home/daniel/build-nghttp3/lib/pkgconfig:/home/daniel/build-ngtcp2/lib/pkgconfig LDFLAGS=-L/home/daniel/build-quictls/lib CFLAGS=-I/home/daniel/build-quictls/include ./configure --enable-maintainer-mode --prefix=/home/daniel/build-nghttp2 --disable-shared --enable-app --enable-http3 --without-jemalloc --without-libxml2 --without-systemd
make && make install
Run the local h3 server on port 9443, make it proxy all traffic through to HTTP/1 on localhost port 80. For local toying, we can just use the test cert that exists in curl's test dir.
CERT=$CURLSRC/tests/stunnel.pem
$HOME/bin/nghttpx $CERT $CERT --backend=localhost,80 \
--frontend="localhost,9443;quic"
Install Caddy. For easiest use, the binary should be either in your PATH or your current directory.
Create a Caddyfile
with the following content:
localhost:7443 {
respond "Hello, world! you are using {http.request.proto}"
}
Then run Caddy:
./caddy start
Making requests to https://localhost:7443
should tell you which protocol is being used.
You can change the hard-coded response to something more useful by replacing respond
with reverse_proxy
or file_server
, for example: reverse_proxy localhost:80