Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

[can-eth-gw-linux.git] / Documentation / networking / ip-sysctl.txt

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index c7fc10724948629c98100b19250f8ee07d9dcd73..dd52d516cb8902da098bbb21a5006cea81b66a74 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -30,16 +30,24 @@ neigh/default/gc_thresh3 - INTEGER
        Maximum number of neighbor entries allowed.  Increase this
        when using large numbers of interfaces and when communicating
        with large numbers of directly-connected peers.
+       Default: 1024
 
 neigh/default/unres_qlen_bytes - INTEGER
        The maximum number of bytes which may be used by packets
        queued for each unresolved address by other network layers.
        (added in linux 3.3)
+       Seting negative value is meaningless and will retrun error.
+       Default: 65536 Bytes(64KB)
 
 neigh/default/unres_qlen - INTEGER
        The maximum number of packets which may be queued for each
        unresolved address by other network layers.
        (deprecated in linux 3.3) : use unres_qlen_bytes instead.
+       Prior to linux 3.3, the default value is 3 which may cause
+       unexpected packet loss. The current default value is calculated
+       according to default value of unres_qlen_bytes and true size of
+       packet.
+       Default: 31
 
 mtu_expires - INTEGER
        Time, in seconds, that cached PMTU information is kept.
@@ -199,15 +207,16 @@ tcp_early_retrans - INTEGER
        Default: 2
 
 tcp_ecn - INTEGER
-       Enable Explicit Congestion Notification (ECN) in TCP. ECN is only
-       used when both ends of the TCP flow support it. It is useful to
-       avoid losses due to congestion (when the bottleneck router supports
-       ECN).
+       Control use of Explicit Congestion Notification (ECN) by TCP.
+       ECN is used only when both ends of the TCP connection indicate
+       support for it.  This feature is useful in avoiding losses due
+       to congestion by allowing supporting routers to signal
+       congestion before having to drop packets.
        Possible values are:
-               0 disable ECN
-               1 ECN enabled
-               2 Only server-side ECN enabled. If the other end does
-                 not support ECN, behavior is like with ECN disabled.
+               0 Disable ECN.  Neither initiate nor accept ECN.
+               1 Always request ECN on outgoing connection attempts.
+               2 Enable ECN when requested by incomming connections
+                 but do not request ECN on outgoing connections.
        Default: 2
 
 tcp_fack - BOOLEAN
@@ -215,15 +224,14 @@ tcp_fack - BOOLEAN
        The value is not used, if tcp_sack is not enabled.
 
 tcp_fin_timeout - INTEGER
-       Time to hold socket in state FIN-WAIT-2, if it was closed
-       by our side. Peer can be broken and never close its side,
-       or even died unexpectedly. Default value is 60sec.
-       Usual value used in 2.2 was 180 seconds, you may restore
-       it, but remember that if your machine is even underloaded WEB server,
-       you risk to overflow memory with kilotons of dead sockets,
-       FIN-WAIT-2 sockets are less dangerous than FIN-WAIT-1,
-       because they eat maximum 1.5K of memory, but they tend
-       to live longer. Cf. tcp_max_orphans.
+       The length of time an orphaned (no longer referenced by any
+       application) connection will remain in the FIN_WAIT_2 state
+       before it is aborted at the local end.  While a perfectly
+       valid "receive only" state for an un-orphaned connection, an
+       orphaned connection in FIN_WAIT_2 state could otherwise wait
+       forever for the remote to close its end of the connection.
+       Cf. tcp_max_orphans
+       Default: 60 seconds
 
 tcp_frto - INTEGER
        Enables Forward RTO-Recovery (F-RTO) defined in RFC4138.
@@ -1514,6 +1522,20 @@ cookie_preserve_enable - BOOLEAN
 
        Default: 1
 
+cookie_hmac_alg - STRING
+       Select the hmac algorithm used when generating the cookie value sent by
+       a listening sctp socket to a connecting client in the INIT-ACK chunk.
+       Valid values are:
+       * md5
+       * sha1
+       * none
+       Ability to assign md5 or sha1 as the selected alg is predicated on the
+       configuarion of those algorithms at build time (CONFIG_CRYPTO_MD5 and
+       CONFIG_CRYPTO_SHA1).
+
+       Default: Dependent on configuration.  MD5 if available, else SHA1 if
+       available, else none.
+
 rcvbuf_policy - INTEGER
        Determines if the receive buffer is attributed to the socket or to
        association.   SCTP supports the capability to create multiple