ppp device stuck on configuring DHCP6 with IPv6AcceptRA=no and UseAddress=no and UplinkInterface=:self

[pimzand]

systemd version the issue has been seen with

254

Used distribution

Fedora 39

Linux kernel version used

6.5.9-300.fc39.x86_64

CPU architectures issue was seen on

x86_64

Component

systemd-networkd

Expected behaviour you didn't see

A PPPoE connection as described in #26681 would reach the "configured" state, like it did in Fedora 38 with systemd 253.

Unexpected behaviour you saw

The PPPoE connection is stuck in "configuring" state.

Steps to reproduce the problem

Set up a PPPoE connection using systemd-networkd and pppd as described in #26681, and include the (then) solution provided in #26681 (comment).

A complete description for the ppp network would be:

[Match]
Type = ppp

[Network]
DHCP = ipv6
LLMNR = no
IPv6AcceptRA = no
KeepConfiguration = yes
DHCPPrefixDelegation = yes

[Link]
RequiredForOnline = yes

[DHCPv6]
UseDelegatedPrefix = yes
UseAddress = no
UseDNS = no

[DHCPPrefixDelegation]
UplinkInterface = :self
Assign = no

This setup is expecting a ppp connection that will be configured using IPCP with a public IPv4 address and a link-local IPv6 address. DHCPv6 would be used only to configure addressing and routing on other interfaces using prefix delegation.

Additional program output to the terminal or log subsystem illustrating the issue

Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: Timeout T1
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: State changed: bound -> renew
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: Sent Renew
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: Next retransmission in 9s
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: Processed Reply message
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: T1 expires in 21h 52min 41s
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: T2 expires in 1d 11h 30min 52s
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: Valid lifetime expires in 3d
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCPv6 client: State changed: renew -> bound
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCP: received delegated prefix aaaa:bbbb:cccc::/48
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: Updated expiration timer for DHCPv6 route (configuring,configured): dst: aaaa:bbbb:cccc::/48, src: n/a, gw: n/a, prefsrc: n/a, scope: global, table: main(254), proto: dhcp, type: unreachable, nexthop: 0, priority: 1024, flags: n/a
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: Requesting DHCPv6 route (configuring,configured): dst: aaaa:bbbb:cccc::/48, src: n/a, gw: n/a, prefsrc: n/a, scope: global, table: main(254), proto: dhcp, type: unreachable, nexthop: 0, priority: 1024, flags: n/a
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: Requesting DHCP-PD route (configuring,configured): dst: aaaa:bbbb:cccc::/64, src: n/a, gw: n/a, prefsrc: n/a, scope: global, table: main(254), proto: dhcp, type: unicast, nexthop: 0, priority: 256, flags: n/a
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: Assigned prefix aaaa:bbbb:cccc::/64
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: link_check_ready(): DHCPv6 IA_PD prefix is assigned, but DHCPv6 protocol is not finished yet.
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: Setting DHCPv6 addresses and routes
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: link_check_ready(): DHCPv6 IA_PD prefix is assigned, but DHCPv6 protocol is not finished yet.
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: Configuring DHCPv6 route (requesting,configuring,configured): dst: aaaa:bbbb:cccc::/48, src: n/a, gw: n/a, prefsrc: n/a, scope: global, table: main(254), proto: dhcp, type: unreachable, nexthop: 0, priority: 1024, flags: n/a
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: Configuring DHCP-PD route (requesting,configuring,configured): dst: aaaa:bbbb:cccc::/64, src: n/a, gw: n/a, prefsrc: n/a, scope: global, table: main(254), proto: dhcp, type: unicast, nexthop: 0, priority: 256, flags: n/a
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: dhcp6_check_ready(): no DHCPv6 address is ready.
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: DHCP-PD addresses and routes set.
Nov 09 21:50:27 fedora systemd-networkd[1766]: ppp0: link_check_ready(): DHCPv6 IA_PD prefix is assigned, but DHCPv6 protocol is not finished yet.

[yuwata]

Thank you!

[yuwata]

Fix is waiting in #29981.

[pimzand]

confirmed fixed in Fedora systemd-254.7-1.fc39