To run test HTTP/3 programs (neqo-client and neqo-server):

• cargo build
• ./target/debug/neqo-server [::]:12345 --db ./test-fixture/db
• ./target/debug/neqo-client http://127.0.0.1:12345/

You can clone NSS (https://hg.mozilla.org/projects/nss) and NSPR (https://hg.mozilla.org/projects/nspr) into the same directory and export an environment variable called NSS_DIR pointing to NSS. This causes the build to use the existing NSS checkout. However, in order to run anything that depends on NSS, you need to set $\[DY]LD\_LIBRARY\_PATH to point to $NSS_DIR/../dist/Debug/lib.

Note: If you did not compile NSS separately, you need to have mercurial (hg), installed. NSS builds require gyp, and ninja (or ninja-build) to be present also.

Info here

TODO: What is the minimum Wireshark version needed? TODO: Above link may be incorrect, protocol now called TLS instead of SSL?

As documented in the env_logger documentation, the RUST_LOG environment variable can be used to selectively enable log messages from Rust code. This works for Neqo's cmdline tools, as well as for when Neqo is incorporated into Gecko, although Gecko needs to be built in debug mode.

Some examples:

1. RUST_LOG=neqo_transport::dump ./mach run lists sent and received QUIC packets and their frames' contents only.
2. RUST_LOG=neqo_transport=debug,neqo_http3=trace,info ./mach run sets a 'debug' log level for transport, 'trace' level for http3, and 'info' log level for all other Rust crates, both Neqo and others used by Gecko.
3. RUST_LOG=neqo=trace,error ./mach run sets trace level for all modules starting with "neqo", and sets error as minimum log level for other unrelated Rust log messages.

In a checked-out copy of Gecko source, set paths for the four Neqo crates to local versions in netwerk/socket/neqo_glue/Cargo.toml. For example, if Neqo was checked out to /home/alice/git/neqo, change:

neqo-http3 = { tag = "v0.1.7", git = "https://github.com/mozilla/neqo" }
neqo-transport = { tag = "v0.1.7", git = "https://github.com/mozilla/neqo" }
neqo-common = { tag = "v0.1.7", git = "https://github.com/mozilla/neqo" }

to

neqo-http3 = { path = "/home/alice/git/neqo/neqo-http3" }
neqo-transport = { path = "/home/alice/git/neqo/neqo-transport" }
neqo-common = { path = "/home/alice/git/neqo/neqo-common" }

and

[dependencies.neqo-crypto]
tag = "v0.1.7"
git = "https://github.com/mozilla/neqo"
default-features = false
features = ["gecko"]

to

[dependencies.neqo-crypto]
path = "/home/alice/git/neqo/neqo-crypto"
default-features = false
features = ["gecko"]

Note: Using newer Neqo code with Gecko may also require changes (likely to neqo_glue) if something has changed.

Compile Gecko as usual with ./mach build.