consomme: ipv6 address discoverability updates#3701
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OneBlue merged 2 commits intoJun 19, 2026
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Pull request overview
This PR updates the net_consomme device’s IPv6 address discovery and NDP behavior to improve guest IPv6 address “learnability” and to optionally suppress advertising a routable SLAAC prefix on adapters intended for local/loopback-only traffic.
Changes:
- Add
advertise_routable_ipv6to control whether Router Advertisements include Prefix Information for SLAAC-based routable address creation. - Improve guest IPv6 address discovery by learning the guest’s link-local address from traffic and inferring link-local from a learned routable EUI-64-based SLAAC address.
- Add more detailed ICMPv6/NDP tracing and a dedicated
UnsupportedIcmpv6drop reason for non-NDP ICMPv6.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| vm/devices/net/net_consomme/src/lib.rs | Treat UnsupportedIcmpv6 drops as “unknown” TX results in queue stats. |
| vm/devices/net/net_consomme/consomme/src/ndp.rs | Add NDP receive tracing and gate RA prefix advertisement on advertise_routable_ipv6. |
| vm/devices/net/net_consomme/consomme/src/lib.rs | Introduce advertise_routable_ipv6, link-local inference from routable EUI-64, link-local learning from traffic, and UnsupportedIcmpv6. |
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| // Check if this is an NDP packet | ||
| let icmpv6_packet = Icmpv6Packet::new_unchecked(inner); | ||
| let msg_type = icmpv6_packet.msg_type(); | ||
|
|
||
| if msg_type == smoltcp::wire::Icmpv6Message::NeighborSolicit | ||
| || msg_type == smoltcp::wire::Icmpv6Message::NeighborAdvert | ||
| || msg_type == smoltcp::wire::Icmpv6Message::RouterSolicit | ||
| || msg_type == smoltcp::wire::Icmpv6Message::RouterAdvert | ||
| { | ||
| if msg_type.is_ndisc() { |
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| let icmpv6_packet = Icmpv6Packet::new_unchecked(payload); | ||
| let msg_type = icmpv6_packet.msg_type(); | ||
| tracing::trace!( | ||
| icmpv6_type = %msg_type, | ||
| ipv6_src_addr = %ipv6_src_addr, | ||
| eth_src_addr = %frame.src_addr, | ||
| eth_dst_addr = %frame.dst_addr, | ||
| "received NDP message" | ||
| ); |
damanm24
approved these changes
Jun 19, 2026
jstarks
reviewed
Jun 19, 2026
| @@ -143,6 +144,10 @@ | |||
| /// Current IPv6 network mask (if any). | |||
| #[inspect(display)] | |||
jstarks
reviewed
Jun 19, 2026
| pub prefix_len_ipv6: u8, | ||
| /// If true, advertise an autonomous IPv6 prefix so guests create a | ||
| /// routable IPv6 address with SLAAC. | ||
| #[inspect(display)] |
jstarks
reviewed
Jun 19, 2026
| pub udp_timeout: Duration, | ||
| /// If true, skip checks for host IPv6 support and assume the host has a | ||
| /// routable IPv6 address. | ||
| #[inspect(display)] |
jstarks
reviewed
Jun 19, 2026
| #[inspect(with = "|x| x.map(inspect::AsDisplay)")] | ||
| pub client_ip_ipv6_routable: Option<Ipv6Address>, | ||
| /// Idle timeout for UDP connections. | ||
| #[inspect(debug)] |
jstarks
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Jun 19, 2026
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Fix inspect now or in a follow up, please.
damanm24
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Jun 19, 2026
Addressing follow-ups requested in #3701 Co-authored-by: Daman Mulye <dmulye2@illinois.edu>
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Consomme updates to expand ipv6 address discovery from the guest.
Adapter can be marked to not advertise routable address availability if traffic on that adapter is only going to be used for local/loopback traffic.
Infer Ipv6 link local address from routable address if the link local address is not yet known and the routable address conforms to a EUI-64 address derived from the guest MAC.
Discover the link local address from sent packets, similar to the routable address.
Additional tracing.