Skip to content

Filter DNS Results by Interface Type #111

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
sgodin wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Filter DNS Results by Interface Type #111

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
663a007
Filter DNS Results by Interface Type
sgodin Nov 6, 2025
9167745
- address some CoPilot suggestions and cleanup logic
sgodin Nov 7, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
49 changes: 45 additions & 4 deletions moq-native-ietf/src/quic.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -303,12 +303,53 @@ impl Client {
let host = url.host().context("invalid DNS name")?.to_string();
let port = url.port().unwrap_or(443);

// Look up the DNS entry.
let addr = tokio::net::lookup_host((host.clone(), port))
// Determine whether our local socket is IPv6 or IPv4
let is_ipv6 = self
.quic
.local_addr()
.context("failed to get local address")?
.is_ipv6();

// Perform DNS lookup to get all addresses
let addrs: Vec<std::net::SocketAddr> = tokio::net::lookup_host((host.clone(), port))
.await
.context("failed DNS lookup")?
.next()
.context("no DNS entries")?;
.collect();

// Fail early if DNS lookup returned no addresses
if addrs.is_empty() {
anyhow::bail!("DNS lookup for host '{}' returned no addresses", host);
}

// Log all DNS responses
for (i, addr) in addrs.iter().enumerate() {
log::debug!(
"DNS[{}] = {} ({})",
i,
addr,
if addr.is_ipv4() { "ipv4" } else { "ipv6" }
);
}

// Select DNS address to use based on local socket type and OS
let chosen = if !is_ipv6 {
// If we are bound to an IPv4 socket, prefer IPv4 addresses
addrs.iter().find(|a| a.is_ipv4()).cloned()
} else if cfg!(target_os = "linux") {
// If IPv6 and running on Linux, then assume dual-stack, and use top DNS result
addrs.first().cloned()
Comment on lines +338 to +340
Copy link

Copilot AI Nov 6, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The logic for Linux dual-stack sockets (line 325) uses the "top DNS result" without any preference for IPv4 or IPv6. While this may work, it's unclear why Linux is treated differently. The comment mentions "dual-stack" which suggests IPv6 sockets on Linux can handle both IPv4 and IPv6, but the code doesn't verify this assumption. If the intent is to handle IPv4-mapped IPv6 addresses on Linux, this should be documented more clearly, or the logic should explicitly check for dual-stack capability rather than assuming it based on OS.

Copilot uses AI. Check for mistakes.
Copy link
Copy Markdown
Contributor Author

@sgodin sgodin Nov 6, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is a reasonable point, I'd like to leave this as a future todo, as the previous logic is still improved here, and not made worse.

} else {
// If IPv6 and not running on Linux: prefer IPv6 addresses
addrs.iter().find(|a| a.is_ipv6()).cloned()
};

// Fail if no compatible address is found
let addr = chosen.context(format!(
"No compatible address found for local socket type (IPv{})",
if is_ipv6 { "6" } else { "4" }
))?;

log::debug!("Connecting to address={}", addr);

let connection = self.quic.connect_with(config, addr, &host)?.await?;

Expand Down