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f2fdb6710f
Currently any error encountered in n_dhcp4_c_connection_dispatch_io()
causes a dispatch failure and interrupts the library state
machine. The recvmsg() on the socket can fail for different reasons;
one of these is for example that the UDP request previously sent got a
ICMP port-unreachable response. This can be reproduced in the
following way:
ip netns add ns1
ip link add veth0 type veth peer name veth1
ip link set veth1 netns ns1
ip link set veth0 up
cat > dhcpd.conf <<EOF
server-identifier 172.25.0.1;
max-lease-time 120;
default-lease-time 120;
subnet 172.25.0.0 netmask 255.255.255.0 {
range 172.25.0.100 172.25.0.200;
}
EOF
ip -n ns1 link set veth1 up
ip -n ns1 address add dev veth1 172.25.0.1/24
ip netns exec ns1 iptables -A INPUT -p udp --dport 67 -j REJECT
ip netns exec ns1 dhcpd -4 -cf dhcpd.conf -pf /tmp/dhcp-server.pid
If a client is started on veth0, it is able to obtain a lease despite
the firewall rule blocking DHCP, because dhcpd uses a packet
socket. Then it fails during the renewal because the recvmsg() fails:
dhcp4 (veth0): send REQUEST of 172.25.0.178 to 172.25.0.1
dhcp4 (veth0): error -111 dispatching events
dhcp4 (veth0): state changed bound -> fail
The client should consider such errors non fatal and keep running.
https://bugzilla.redhat.com/show_bug.cgi?id=1829178
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/486
(cherry picked from commit
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| .. | ||
| c-list | ||
| c-rbtree | ||
| c-siphash | ||
| c-stdaux | ||
| n-acd | ||
| n-dhcp4 | ||
| nm-glib-aux | ||
| nm-libnm-core-aux | ||
| nm-libnm-core-intern | ||
| nm-std-aux | ||
| nm-udev-aux | ||
| nm-utils | ||
| systemd | ||
| meson.build | ||
| nm-default.h | ||
| nm-meta-setting.c | ||
| nm-meta-setting.h | ||
| nm-test-libnm-utils.h | ||
| nm-test-utils-impl.c | ||
| nm-version-macros.h.in | ||