sctp: Add documentation for sctp sysctl variable

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 170 insertions, 0 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 17f1f91af35c..277437951e4d 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1060,6 +1060,176 @@ bridge-nf-filter-pppoe-tagged - BOOLEAN
         Default: 1
 
 
+proc/sys/net/sctp/* Variables:
+
+addip_enable - BOOLEAN
+        Enable or disable extension of  Dynamic Address Reconfiguration
+        (ADD-IP) functionality specified in RFC5061.  This extension provides
+        the ability to dynamically add and remove new addresses for the SCTP
+        associations.
+
+        1: Enable extension.
+
+        0: Disable extension.
+
+        Default: 0
+
+addip_noauth_enable - BOOLEAN
+        Dynamic Address Reconfiguration (ADD-IP) requires the use of
+        authentication to protect the operations of adding or removing new
+        addresses.  This requirement is mandated so that unauthorized hosts
+        would not be able to hijack associations.  However, older
+        implementations may not have implemented this requirement while
+        allowing the ADD-IP extension.  For reasons of interoperability,
+        we provide this variable to control the enforcement of the
+        authentication requirement.
+
+        1: Allow ADD-IP extension to be used without authentication.  This
+           should only be set in a closed environment for interoperability
+           with older implementations.
+
+        0: Enforce the authentication requirement
+
+        Default: 0
+
+auth_enable - BOOLEAN
+        Enable or disable Authenticated Chunks extension.  This extension
+        provides the ability to send and receive authenticated chunks and is
+        required for secure operation of Dynamic Address Reconfiguration
+        (ADD-IP) extension.
+
+        1: Enable this extension.
+        0: Disable this extension.
+
+        Default: 0
+
+prsctp_enable - BOOLEAN
+        Enable or disable the Partial Reliability extension (RFC3758) which
+        is used to notify peers that a given DATA should no longer be expected.
+
+        1: Enable extension
+        0: Disable
+
+        Default: 1
+
+max_burst - INTEGER
+        The limit of the number of new packets that can be initially sent.  It
+        controls how bursty the generated traffic can be.
+
+        Default: 4
+
+association_max_retrans - INTEGER
+        Set the maximum number for retransmissions that an association can
+        attempt deciding that the remote end is unreachable.  If this value
+        is exceeded, the association is terminated.
+
+        Default: 10
+
+max_init_retransmits - INTEGER
+        The maximum number of retransmissions of INIT and COOKIE-ECHO chunks
+        that an association will attempt before declaring the destination
+        unreachable and terminating.
+
+        Default: 8
+
+path_max_retrans - INTEGER
+        The maximum number of retransmissions that will be attempted on a given
+        path.  Once this threshold is exceeded, the path is considered
+        unreachable, and new traffic will use a different path when the
+        association is multihomed.
+
+        Default: 5
+
+rto_initial - INTEGER
+        The initial round trip timeout value in milliseconds that will be used
+        in calculating round trip times.  This is the initial time interval
+        for retransmissions.
+
+        Default: 3000
+
+rto_max - INTEGER
+        The maximum value (in milliseconds) of the round trip timeout.  This
+        is the largest time interval that can elapse between retransmissions.
+
+        Default: 60000
+
+rto_min - INTEGER
+        The minimum value (in milliseconds) of the round trip timeout.  This
+        is the smallest time interval the can elapse between retransmissions.
+
+        Default: 1000
+
+hb_interval - INTEGER
+        The interval (in milliseconds) between HEARTBEAT chunks.  These chunks
+        are sent at the specified interval on idle paths to probe the state of
+        a given path between 2 associations.
+
+        Default: 30000
+
+sack_timeout - INTEGER
+        The amount of time (in milliseconds) that the implementation will wait
+        to send a SACK.
+
+        Default: 200
+
+valid_cookie_life - INTEGER
+        The default lifetime of the SCTP cookie (in milliseconds).  The cookie
+        is used during association establishment.
+
+        Default: 60000
+
+cookie_preserve_enable - BOOLEAN
+        Enable or disable the ability to extend the lifetime of the SCTP cookie
+        that is used during the establishment phase of SCTP association
+
+        1: Enable cookie lifetime extension.
+        0: Disable
+
+        Default: 1
+
+rcvbuf_policy - INTEGER
+        Determines if the receive buffer is attributed to the socket or to
+        association.   SCTP supports the capability to create multiple
+        associations on a single socket.  When using this capability, it is
+        possible that a single stalled association that's buffering a lot
+        of data may block other associations from delivering their data by
+        consuming all of the receive buffer space.  To work around this,
+        the rcvbuf_policy could be set to attribute the receiver buffer space
+        to each association instead of the socket.  This prevents the described
+        blocking.
+
+        1: rcvbuf space is per association
+        0: recbuf space is per socket
+
+        Default: 0
+
+sndbuf_policy - INTEGER
+        Similar to rcvbuf_policy above, this applies to send buffer space.
+
+        1: Send buffer is tracked per association
+        0: Send buffer is tracked per socket.
+
+        Default: 0
+
+sctp_mem - vector of 3 INTEGERs: min, pressure, max
+        Number of pages allowed for queueing by all SCTP sockets.
+
+        min: Below this number of pages SCTP is not bothered about its
+        memory appetite. When amount of memory allocated by SCTP exceeds
+        this number, SCTP starts to moderate memory usage.
+
+        pressure: This value was introduced to follow format of tcp_mem.
+
+        max: Number of pages allowed for queueing by all SCTP sockets.
+
+        Default is calculated at boot time from amount of available memory.
+
+sctp_rmem - vector of 3 INTEGERs: min, default, max
+        See tcp_rmem for a description.
+
+sctp_wmem  - vector of 3 INTEGERs: min, default, max
+        See tcp_wmem for a description.
+
 UNDOCUMENTED:
 
 dev_weight FIXME