[NetLabel]: documentation

Documentation for the NetLabel system, this includes a basic overview
of how NetLabel works, how LSM developers can integrate it into their
favorite LSM, as well as documentation on the CIPSO related sysctl
variables.  Also, due to the difficulty of finding expired IETF
drafts, I am including the IETF CIPSO draft that is the basis of the
NetLabel CIPSO implementation.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 35 insertions, 0 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 90ed78110fd4..307cd4ec8edd 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -375,6 +375,41 @@ tcp_slow_start_after_idle - BOOLEAN
         be timed out after an idle period.
         Default: 1
 
+CIPSOv4 Variables:
+
+cipso_cache_enable - BOOLEAN
+        If set, enable additions to and lookups from the CIPSO label mapping
+        cache.  If unset, additions are ignored and lookups always result in a
+        miss.  However, regardless of the setting the cache is still
+        invalidated when required when means you can safely toggle this on and
+        off and the cache will always be "safe".
+        Default: 1
+
+cipso_cache_bucket_size - INTEGER
+        The CIPSO label cache consists of a fixed size hash table with each
+        hash bucket containing a number of cache entries.  This variable limits
+        the number of entries in each hash bucket; the larger the value the
+        more CIPSO label mappings that can be cached.  When the number of
+        entries in a given hash bucket reaches this limit adding new entries
+        causes the oldest entry in the bucket to be removed to make room.
+        Default: 10
+
+cipso_rbm_optfmt - BOOLEAN
+        Enable the "Optimized Tag 1 Format" as defined in section 3.4.2.6 of
+        the CIPSO draft specification (see Documentation/netlabel for details).
+        This means that when set the CIPSO tag will be padded with empty
+        categories in order to make the packet data 32-bit aligned.
+        Default: 0
+
+cipso_rbm_structvalid - BOOLEAN
+        If set, do a very strict check of the CIPSO option when
+        ip_options_compile() is called.  If unset, relax the checks done during
+        ip_options_compile().  Either way is "safe" as errors are caught else
+        where in the CIPSO processing code but setting this to 0 (False) should
+        result in less work (i.e. it should be faster) but could cause problems
+        with other implementations that require strict checking.
+        Default: 0
+
 IP Variables:
 
 ip_local_port_range - 2 INTEGERS