Netopeer2 – NETCONF Server

Netopeer2 is a server for implementing network configuration management based on the NETCONF Protocol. This is the second generation, originally available as the Netopeer project. Netopeer2 is based on the new generation of the NETCONF and YANG libraries - libyang and libnetconf2. The Netopeer2 server uses sysrepo as a NETCONF datastore implementation.

Netopeer2 is maintained and further developed by the Tools for Monitoring and Configuration department of CESNET. Any feedback, testing or feature requests are welcome. Please contact us via the issue tracker.

Branches

The project uses 2 main branches master and devel. Other branches should not be cloned. In master there are files of the last official release. Any latest improvements and changes (of the server), which were tested at least briefly are found in devel. On every new release, devel is merged into master.

This means that when only stable official releases are to be used, either master can be used or specific releases downloaded. If all the latest bugfixes should be applied, devel branch is the one to be used. Note that whenever a new issue is created and it occurs on the master branch, the first response will likely be to use devel before any further provided support.

RFC Compliance

• RFC 5277 NETCONF Event Notifications
• RFC 6022 YANG Module for NETCONF Monitoring
• RFC 6241 Network Configuration Protocol (NETCONF)
• RFC 6242 Using the NETCONF Protocol over Secure Shell (SSH)
• RFC 6243 With-defaults Capability for NETCONF
• RFC 6470 Network Configuration Protocol (NETCONF) Base Notifications
• RFC 7589 Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication
• RFC 8071 NETCONF Call Home and RESTCONF Call Home
• RFC 8341 Network Configuration Access Control Model
• RFC 8525 YANG Library
• RFC 8526 NETCONF Extensions to Support the Network Management Datastore Architecture
• RFC 8639 Subscription to YANG Notifications
• RFC 8640 Dynamic Subscription to YANG Events and Datastores over NETCONF
• RFC 8641 Subscription to YANG Notifications for Datastore Updates

Packages

Binary RPM or DEB packages of the latest release can be built locally using apkg, look into README in the distro directory.

Requirements

• libyang
• libnetconf2
• sysrepo

Optional

• pkg-config & libsystemd (to support netopeer2-server systemd service)
• cmocka >= 1.0.1 (for tests)
• valgrind (for enhanced testing)
• gcov (for code coverage)
• lcov (for code coverage)
• genhtml (for code coverage)

Compilation and installation

$ mkdir build; cd build
$ cmake ..
$ make
# make install

Compilation options

The netopeer2-server requires ietf-netconf-server and all connected YANG modules to be installed in sysrepo to work correctly. This is performed automatically during the installation process. Moreover, default SSH configuration listening on all IPv4 interfaces and a newly generated SSH host key are imported so that it can be connected to the server out-of-the-box. However, it may not always be desired to perform all these steps even though the executed scripts check whether the modules/some configuration already exist and do not repeat/overwrite any modules/configuration.

This is the option that affects the initial setup:

SYSREPO_SETUP:ON

If cross-compiling for a different architecture, you will likely want to turn this option off and then run the scripts setup.sh, merge_hostkey.sh, and merge_config.sh manually.

Server configuration

By default, only SSH listen configuration is imported so to enable any other connection methods, they need to be configured manually. The default SSH listen configuration will define one of the following two means of authentication only for the user that executed the script to install netopeer2. The first is via the SSH public key authentication method, which will be set if authorized_keys file is found and the keys from this file will be used. If authorized_keys file is not found, the second method is via the SSH keyboard-interactive, which leaves the authentication up to the system (and depends on how libnetconf2 was compiled but if it supports PAM, netopeer2.conf PAM configuration file will be used, which can be customized manually).

Example configuration XML files can be found in the example_configuration directory. These files can be easily modified to create configuration specific for a particular environment and configured authentication.

SSH Call Home

To enable SSH Call Home, only ssh_callhome.xml file needs to be imported to sysrepo provided that the default SSH host key genkey was imported into ietf-keystore configuration.

TLS listen

To support clients connecting using TLS, configuration files tls_keystore.xml, tls_truststore.xml, and tls_listen.xml needs to be merged into sysrepo configuration of modules ietf-keystore, ietf-truststore, and ietf-netconf-server, respectively. After doing so, a NETCONF client can connect using client.crt certificate and client.key private key and having ca.pem CA certificate set as trusted. These example certificates can be found in example_configuration/tls_certs. netopeer2-cli can easily be configured this way and the TLS connection tested.

To pass server identity check, the client must be connecting to localhost, which is the default server domain if left empty. Once connected, the client will be identified with tls-test NETCONF username.

TLS Call Home

Using the same certificates and authorization options, a TLS client can be connected to using Call Home when tls_callhome.xml file is imported. But tls_keystore.xml and tls_truststore.xml need to be imported first.

NACM

This NETCONF server uses ietf-netconf-acm access control of sysrepo. NACM is enabled by default, so except for the recovery user, no others will be allowed to write any data but should be granted read and execute permissions unless the access was modified by a NACM extension. When deploying this server, it is strongly advised to configure NACM properly.

Sysrepo callbacks

When implementing a sysrepo application with some callbacks, in case the particular event will be generated by netopeer2, there will be the NETCONF session ID and NETCONF username of the originator NETCONF session provided. It can be retrieved from the event sysrepo session and the originator name will be netopeer2. Following is a table with the exact data format.

It is also possible to communicate a specific NETCONF error back to the server, use sysrepo utility functions to create it.

CLI

A simple command-line NETCONF client netopeer2-cli is included and build/installed by default. This can be adjusted by an option:

BUILD_CLI:ON

There is also a separate netconf-cli project that you may want to give a try if you need an advanced and more user-friendly command-line NETCONF client.

Tests

There are several tests included and built with cmocka. The tests can be found in tests subdirectory and they are designed for checking library functionality after code changes.

The tests are by default built in the Debug build mode by running

$ make

In case of the Release mode, the tests are not built by default (it requires additional dependency), but they can be enabled via cmake option:

$ cmake -DENABLE_TESTS=ON ..

Note that if the necessary cmocka headers are not present in the system include paths, tests are not available despite the build mode or cmake's options.

Tests can be run by the make's test target:

$ make test

Code Coverage

Based on the tests run, it is possible to generate code coverage report. But it must be enabled and these commands are needed to generate the report:

$ cmake -DENABLE_COVERAGE=ON ..
$ make
$ make coverage