About
This program is openconnect VPN server (ocserv), a server for the openconnect VPN client. It follows the openconnect protocol and is believed to be compatible with CISCO's AnyConnect SSL VPN.
The program consists of:
- ocserv, the main server application
- occtl, the server's control tool. A tool which allows one to query the server for information.
- ocpasswd, a tool to administer simple password files.
Supported platforms
The OpenConnect VPN server is designed and tested to work, with both IPv6 and IPv4, on Linux systems. It is, however, known to work on FreeBSD, OpenBSD and other BSD derived systems.
Known limitation is that on platforms, which do not support procfs(5), changes to the configuration must only be made while ocserv(8) is stopped. Not doing so will cause new worker processes picking up the new configuration while ocserv-main will use the previous configuration.
Build dependencies
Required dependencies (Debian pkg/Fedora pkg):
libgnutls28-dev / gnutls-devel
libev-dev / libev-devel
Optional dependencies that enable specific functionality:
TCP wrappers: libwrap0-dev / tcp_wrappers-devel
PAM: libpam0g-dev / pam-devel
LZ4: liblz4-dev / lz4-devel
seccomp: libseccomp-dev / libseccomp-devel
occtl: libreadline-dev / readline-devel
libnl-route-3-dev / libnl3-devel
GSSAPI: libkrb5-dev / krb5-devel
Radius: libradcli-dev / radcli-devel
OIDC: libcurl4-gnutls-dev / libcurl-devel
libcjose-dev / cjose-devel
libjansson-dev / jansson-devel
Dependencies for development, testing, or dependencies that can be skipped in an embedded system (e.g., because a replacement library is included):
libprotobuf-c-dev / protobuf-c-devel
libtalloc-dev / libtalloc-devel
libhttp-parser-dev / http-parser-devel
protobuf-c-compiler/ protobuf-c
gperf / gperf
nuttcp / nuttcp
lcov / lcov
libuid-wrapper / uid_wrapper
libpam-wrapper / pam_wrapper
libnss-wrapper / nss_wrapper
libsocket-wrapper / socket_wrapper
gss-ntlmssp / gssntlmssp
haproxy / haproxy
iputils-ping / iputils
freeradius / freeradius
gawk / gawk
gnutls-bin / gnutls-utils
iproute2 / iproute
yajl-tools / yajl
iproute2 / iproute
tcpdump / tcpdump
See README-radius for more information on Radius dependencies and its configuration.
Build instructions
To build from a distributed release use:
$ ./configure && make && make check
To test the code coverage of the test suite use the following:
$ ./configure --enable-code-coverage
$ make && make check && make code-coverage-capture
Note that the code coverage reported does not currently include tests which are run within docker.
In addition to the prerequisites listed above, building from git requires the following packages: autoconf, automake, and xz.
To build from the git repository use:
$ autoreconf -fvi
$ ./configure && make
Basic installation instructions
Now you need to generate a certificate. E.g.
$ certtool --generate-privkey > ./test-key.pem
$ certtool --generate-self-signed --load-privkey test-key.pem --outfile test-cert.pem
(make sure you enable encryption or signing)
Create a dedicated user and group for the server unprivileged processes (e.g., 'ocserv'), and then edit the sample.config and set these users on run-as-user and run-as-group options. The run:
# cd doc && ../src/ocserv -f -c sample.config
Configuration
Several configuration instruction are available in the recipes repository.
Profiling
If you use ocserv on a server with significant load and you'd like to help improve it, you may help by sending profiling information. That includes the bottlenecks in software, so future optimizations could be spent on the real needs.
In a Linux system you can profile ocserv using the following command.
# perf record -g ocserv
After the server is terminated, the output is placed in perf.data. You may examine the output using:
# perf report
Continuous Integration (CI)
We utilize the gitlab-ci continuous integration system. It is used to test most of the Linux systems (see .gitlab-ci.yml),and is split in two phases, build image creation and compilation/test. The build image creation is done at the openconnect/build-images subproject and uploads the image at the gitlab.com container registry. The compilation/test phase is on every commit to project.
How the VPN works
Please see the technical description page.