libbsd.txt: Move IPsec description

README.rst

@@ -513,6 +513,151 @@ Known Restrictions
 * The control interface of ``wpa_supplicant`` most likely doesn't work. The wpa_cli
   application is not ported.
 
+IPSec
+=====
+
+The IPSec support is optional in LibBSD. It is disabled in the default build
+set. Please make sure to use a build set with ``netipsec = on``.
+
+Configuration
+-------------
+
+To use IPSec the following configuration is necessary:
+
+.. code-block:: none
+
+    SYSINIT_MODULE_REFERENCE(if_gif);
+    SYSINIT_MODULE_REFERENCE(cryptodev);
+    RTEMS_BSD_RC_CONF_SYSINT(rc_conf_ipsec)
+    RTEMS_BSD_DEFINE_NEXUS_DEVICE(cryptosoft, 0, 0, NULL);
+
+Alternatively, you can use the ``RTEMS_BSD_CONFIG_IPSEC`` which also includes the
+rc.conf support for ipsec. It's still necessary to include a crypto device in
+your config (``cryptosoft`` in the above sample).
+
+The necessary initialization steps for a IPSec connection are similar to the
+steps on a FreeBSD-System. The example assumes the following setup:
+
+- RTEMS external IP: 192.168.10.1/24
+- RTEMS internal IP: 10.10.1.1/24
+- remote external IP: 192.168.10.10/24
+- remote internal IP: 172.24.0.1/24
+- shared key: "mysecretkey"
+
+With this the following steps are necessary:
+
+* Create a gif0 device:
+
+  .. code-block:: none
+
+      ifconfig gif0 create
+
+* Configure the gif0 device:
+
+  .. code-block:: none
+
+      ifconfig gif0 10.10.1.1 172.24.0.1
+      ifconfig gif0 tunnel 192.168.10.1 192.168.10.10
+
+* Add a route to the remote net via the remote IP:
+
+  .. code-block:: none
+
+      route add 172.24.0.0/24 172.24.0.1
+
+* Create a correct rule set in ``/etc/setkey.conf``:
+
+  .. code-block:: none
+
+      flush;
+      spdflush;
+      spdadd  10.10.1.0/24 172.24.0.0/24 any -P out ipsec esp/tunnel/192.168.10.1-192.168.10.10/use;
+      spdadd 172.24.0.0/24  10.10.1.0/24 any -P in  ipsec esp/tunnel/192.168.10.10-192.168.10.1/use;
+
+* Call ``setkey``:
+
+  .. code-block:: none
+
+      setkey -f /etc/setkey.conf
+
+* Create a correct configuration in ``/etc/racoon.conf``:
+
+  .. code-block:: none
+
+      path    pre_shared_key "/etc/racoon_psk.txt";
+      log     info;
+
+      padding # options are not to be changed
+      {
+              maximum_length                  20;
+              randomize                       off;
+              strict_check                    off;
+              exclusive_tail                  off;
+      }
+
+      listen  # address [port] that racoon will listen on
+      {
+              isakmp                          192.168.10.1[500];
+      }
+
+      remote 192.168.10.10 [500]
+      {
+              exchange_mode                   main;
+              my_identifier                   address 192.168.10.1;
+              peers_identifier                address 192.168.10.10;
+              proposal_check                  obey;
+              proposal {
+                      encryption_algorithm    3des;
+                      hash_algorithm          md5;
+                      authentication_method   pre_shared_key;
+                      lifetime                time 3600 sec;
+                      dh_group                2;
+              }
+      }
+
+      sainfo (address 10.10.1.0/24 any address 172.24.0.0/24 any)
+      {
+              pfs_group                       2;
+              lifetime                        time 28800 sec;
+              encryption_algorithm            3des;
+              authentication_algorithm        hmac_md5;
+              compression_algorithm           deflate;
+      }
+
+* Create a correct configuration in ``/etc/racoon_psk.txt``:
+
+  .. code-block:: none
+
+     192.168.10.10   mysecretkey
+
+* Start a ike-daemon (racoon):
+
+  .. code-block:: none
+
+      racoon -F -f /etc/racoon.conf
+----
+
+All commands can be called via the respective API functions. For racoon there is
+a ``rtems_bsd_racoon_daemon()`` function that forks of racoon as a task.
+
+Alternatively, IPSec can also be configured via rc.conf entries:
+
+.. code-block:: none
+
+      cloned_interfaces="gif0"
+      ifconfig_gif0="10.10.1.1 172.24.0.1 tunnel 192.168.10.1 192.168.10.10"
+      ike_enable="YES"
+      ike_program="racoon"
+      ike_flags="-F -f /etc/racoon.conf"
+      ike_priority="250"
+
+      ipsec_enable="YES"
+      ipsec_file="/etc/setkey.conf"
+
+ATTENTION: It is possible that the first packets slip through the tunnel without
+encryption (true for FreeBSD as well as RTEMS). You might want to set up a
+firewall rule to prevent that.
+
 Updating RTEMS Waf Support
 ==========================