system/NetworkManager
system/NetworkManager
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/NetworkManager/NetworkManager synced 2024-11-05 19:03:31 +00:00
Code Issues Projects Releases Packages Wiki Activity
NetworkManager/shared/n-dhcp4
History
Beniamino Galvani bee01292f8 n-dhcp4: don't fail dispatch in case of receive errors 
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 c5d1d4c498)
2020-04-30 18:15:42 +02:00
..
.cherryci
src n-dhcp4: don't fail dispatch in case of receive errors 2020-04-30 18:15:42 +02:00
subprojects
.editorconfig
.gitmodules
.travis.yml n-dhcp4: ci: drop broken armv7hl 2019-11-20 10:50:17 +01:00
AUTHORS
meson.build license: Add license using SPDX identifiers to meson build files 2020-02-17 13:16:57 +01:00
NEWS.md
README.md

README.md

n-dhcp4

Dynamic Host Configuration Protocol for IPv4

The n-dhcp4 project implements the IPv4 Dynamic Host Configuration Protocol as defined in RFC-2132+.

Project

Requirements

The requirements for this project are:

  • Linux kernel >= 3.19
  • libc (e.g., glibc >= 2.16)

At build-time, the following software is required:

  • meson >= 0.41
  • pkg-config >= 0.29

Build

The meson build-system is used for this project. Contact upstream documentation for detailed help. In most situations the following commands are sufficient to build and install from source:

mkdir build
cd build
meson setup ..
ninja
meson test
ninja install

No custom configuration options are available.

Repository:

License:

  • Apache-2.0 OR LGPL-2.1-or-later
  • See AUTHORS file for details.