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-rw-r--r--Documentation/networking/ip-sysctl.txt56
1 files changed, 39 insertions, 17 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index c7fc10724948..dd52d516cb89 100644
--- 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