2005-04-17 06:20:36 +08:00
|
|
|
/proc/sys/net/ipv4/* Variables:
|
|
|
|
|
|
|
|
ip_forward - BOOLEAN
|
|
|
|
0 - disabled (default)
|
2009-02-23 12:39:04 +08:00
|
|
|
not 0 - enabled
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
Forward Packets between interfaces.
|
|
|
|
|
|
|
|
This variable is special, its change resets all configuration
|
|
|
|
parameters to their default state (RFC1122 for hosts, RFC1812
|
|
|
|
for routers)
|
|
|
|
|
|
|
|
ip_default_ttl - INTEGER
|
2010-12-14 04:50:49 +08:00
|
|
|
Default value of TTL field (Time To Live) for outgoing (but not
|
|
|
|
forwarded) IP packets. Should be between 1 and 255 inclusive.
|
|
|
|
Default: 64 (as recommended by RFC1700)
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
ip_no_pmtu_disc - BOOLEAN
|
|
|
|
Disable Path MTU Discovery.
|
|
|
|
default FALSE
|
|
|
|
|
|
|
|
min_pmtu - INTEGER
|
2011-11-09 03:21:44 +08:00
|
|
|
default 552 - minimum discovered Path MTU
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2010-11-08 17:13:48 +08:00
|
|
|
route/max_size - INTEGER
|
|
|
|
Maximum number of routes allowed in the kernel. Increase
|
|
|
|
this when using large numbers of interfaces and/or routes.
|
|
|
|
|
2013-01-22 13:20:05 +08:00
|
|
|
neigh/default/gc_thresh1 - INTEGER
|
|
|
|
Minimum number of entries to keep. Garbage collector will not
|
|
|
|
purge entries if there are fewer than this number.
|
2013-03-15 06:49:47 +08:00
|
|
|
Default: 128
|
2013-01-22 13:20:05 +08:00
|
|
|
|
2010-11-08 17:13:48 +08:00
|
|
|
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.
|
2012-12-05 02:50:35 +08:00
|
|
|
Default: 1024
|
2010-11-08 17:13:48 +08:00
|
|
|
|
neigh: new unresolved queue limits
Le mercredi 09 novembre 2011 à 16:21 -0500, David Miller a écrit :
> From: David Miller <davem@davemloft.net>
> Date: Wed, 09 Nov 2011 16:16:44 -0500 (EST)
>
> > From: Eric Dumazet <eric.dumazet@gmail.com>
> > Date: Wed, 09 Nov 2011 12:14:09 +0100
> >
> >> unres_qlen is the number of frames we are able to queue per unresolved
> >> neighbour. Its default value (3) was never changed and is responsible
> >> for strange drops, especially if IP fragments are used, or multiple
> >> sessions start in parallel. Even a single tcp flow can hit this limit.
> > ...
> >
> > Ok, I've applied this, let's see what happens :-)
>
> Early answer, build fails.
>
> Please test build this patch with DECNET enabled and resubmit. The
> decnet neigh layer still refers to the removed ->queue_len member.
>
> Thanks.
Ouch, this was fixed on one machine yesterday, but not the other one I
used this morning, sorry.
[PATCH V5 net-next] neigh: new unresolved queue limits
unres_qlen is the number of frames we are able to queue per unresolved
neighbour. Its default value (3) was never changed and is responsible
for strange drops, especially if IP fragments are used, or multiple
sessions start in parallel. Even a single tcp flow can hit this limit.
$ arp -d 192.168.20.108 ; ping -c 2 -s 8000 192.168.20.108
PING 192.168.20.108 (192.168.20.108) 8000(8028) bytes of data.
8008 bytes from 192.168.20.108: icmp_seq=2 ttl=64 time=0.322 ms
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-09 20:07:14 +08:00
|
|
|
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)
|
2013-01-03 15:50:29 +08:00
|
|
|
Setting negative value is meaningless and will return error.
|
2012-12-05 02:50:35 +08:00
|
|
|
Default: 65536 Bytes(64KB)
|
neigh: new unresolved queue limits
Le mercredi 09 novembre 2011 à 16:21 -0500, David Miller a écrit :
> From: David Miller <davem@davemloft.net>
> Date: Wed, 09 Nov 2011 16:16:44 -0500 (EST)
>
> > From: Eric Dumazet <eric.dumazet@gmail.com>
> > Date: Wed, 09 Nov 2011 12:14:09 +0100
> >
> >> unres_qlen is the number of frames we are able to queue per unresolved
> >> neighbour. Its default value (3) was never changed and is responsible
> >> for strange drops, especially if IP fragments are used, or multiple
> >> sessions start in parallel. Even a single tcp flow can hit this limit.
> > ...
> >
> > Ok, I've applied this, let's see what happens :-)
>
> Early answer, build fails.
>
> Please test build this patch with DECNET enabled and resubmit. The
> decnet neigh layer still refers to the removed ->queue_len member.
>
> Thanks.
Ouch, this was fixed on one machine yesterday, but not the other one I
used this morning, sorry.
[PATCH V5 net-next] neigh: new unresolved queue limits
unres_qlen is the number of frames we are able to queue per unresolved
neighbour. Its default value (3) was never changed and is responsible
for strange drops, especially if IP fragments are used, or multiple
sessions start in parallel. Even a single tcp flow can hit this limit.
$ arp -d 192.168.20.108 ; ping -c 2 -s 8000 192.168.20.108
PING 192.168.20.108 (192.168.20.108) 8000(8028) bytes of data.
8008 bytes from 192.168.20.108: icmp_seq=2 ttl=64 time=0.322 ms
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-09 20:07:14 +08:00
|
|
|
|
|
|
|
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.
|
2012-12-05 02:50:35 +08:00
|
|
|
Prior to linux 3.3, the default value is 3 which may cause
|
2012-12-07 00:27:51 +08:00
|
|
|
unexpected packet loss. The current default value is calculated
|
2012-12-05 02:50:35 +08:00
|
|
|
according to default value of unres_qlen_bytes and true size of
|
|
|
|
packet.
|
|
|
|
Default: 31
|
neigh: new unresolved queue limits
Le mercredi 09 novembre 2011 à 16:21 -0500, David Miller a écrit :
> From: David Miller <davem@davemloft.net>
> Date: Wed, 09 Nov 2011 16:16:44 -0500 (EST)
>
> > From: Eric Dumazet <eric.dumazet@gmail.com>
> > Date: Wed, 09 Nov 2011 12:14:09 +0100
> >
> >> unres_qlen is the number of frames we are able to queue per unresolved
> >> neighbour. Its default value (3) was never changed and is responsible
> >> for strange drops, especially if IP fragments are used, or multiple
> >> sessions start in parallel. Even a single tcp flow can hit this limit.
> > ...
> >
> > Ok, I've applied this, let's see what happens :-)
>
> Early answer, build fails.
>
> Please test build this patch with DECNET enabled and resubmit. The
> decnet neigh layer still refers to the removed ->queue_len member.
>
> Thanks.
Ouch, this was fixed on one machine yesterday, but not the other one I
used this morning, sorry.
[PATCH V5 net-next] neigh: new unresolved queue limits
unres_qlen is the number of frames we are able to queue per unresolved
neighbour. Its default value (3) was never changed and is responsible
for strange drops, especially if IP fragments are used, or multiple
sessions start in parallel. Even a single tcp flow can hit this limit.
$ arp -d 192.168.20.108 ; ping -c 2 -s 8000 192.168.20.108
PING 192.168.20.108 (192.168.20.108) 8000(8028) bytes of data.
8008 bytes from 192.168.20.108: icmp_seq=2 ttl=64 time=0.322 ms
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-09 20:07:14 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
mtu_expires - INTEGER
|
|
|
|
Time, in seconds, that cached PMTU information is kept.
|
|
|
|
|
|
|
|
min_adv_mss - INTEGER
|
|
|
|
The advertised MSS depends on the first hop route MTU, but will
|
|
|
|
never be lower than this setting.
|
|
|
|
|
|
|
|
IP Fragmentation:
|
|
|
|
|
|
|
|
ipfrag_high_thresh - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
Maximum memory used to reassemble IP fragments. When
|
2005-04-17 06:20:36 +08:00
|
|
|
ipfrag_high_thresh bytes of memory is allocated for this purpose,
|
|
|
|
the fragment handler will toss packets until ipfrag_low_thresh
|
|
|
|
is reached.
|
2009-02-23 12:39:04 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
ipfrag_low_thresh - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
See ipfrag_high_thresh
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
ipfrag_time - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
Time in seconds to keep an IP fragment in memory.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
ipfrag_secret_interval - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
Regeneration interval (in seconds) of the hash secret (or lifetime
|
2005-04-17 06:20:36 +08:00
|
|
|
for the hash secret) for IP fragments.
|
|
|
|
Default: 600
|
|
|
|
|
2005-12-14 15:14:27 +08:00
|
|
|
ipfrag_max_dist - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
ipfrag_max_dist is a non-negative integer value which defines the
|
|
|
|
maximum "disorder" which is allowed among fragments which share a
|
|
|
|
common IP source address. Note that reordering of packets is
|
|
|
|
not unusual, but if a large number of fragments arrive from a source
|
|
|
|
IP address while a particular fragment queue remains incomplete, it
|
|
|
|
probably indicates that one or more fragments belonging to that queue
|
|
|
|
have been lost. When ipfrag_max_dist is positive, an additional check
|
|
|
|
is done on fragments before they are added to a reassembly queue - if
|
|
|
|
ipfrag_max_dist (or more) fragments have arrived from a particular IP
|
|
|
|
address between additions to any IP fragment queue using that source
|
|
|
|
address, it's presumed that one or more fragments in the queue are
|
|
|
|
lost. The existing fragment queue will be dropped, and a new one
|
2005-12-14 15:14:27 +08:00
|
|
|
started. An ipfrag_max_dist value of zero disables this check.
|
|
|
|
|
|
|
|
Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can
|
|
|
|
result in unnecessarily dropping fragment queues when normal
|
2009-02-23 12:39:04 +08:00
|
|
|
reordering of packets occurs, which could lead to poor application
|
|
|
|
performance. Using a very large value, e.g. 50000, increases the
|
|
|
|
likelihood of incorrectly reassembling IP fragments that originate
|
2005-12-14 15:14:27 +08:00
|
|
|
from different IP datagrams, which could result in data corruption.
|
|
|
|
Default: 64
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
INET peer storage:
|
|
|
|
|
|
|
|
inet_peer_threshold - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
The approximate size of the storage. Starting from this threshold
|
2005-04-17 06:20:36 +08:00
|
|
|
entries will be thrown aggressively. This threshold also determines
|
|
|
|
entries' time-to-live and time intervals between garbage collection
|
|
|
|
passes. More entries, less time-to-live, less GC interval.
|
|
|
|
|
|
|
|
inet_peer_minttl - INTEGER
|
|
|
|
Minimum time-to-live of entries. Should be enough to cover fragment
|
|
|
|
time-to-live on the reassembling side. This minimum time-to-live is
|
|
|
|
guaranteed if the pool size is less than inet_peer_threshold.
|
2008-07-02 08:22:48 +08:00
|
|
|
Measured in seconds.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
inet_peer_maxttl - INTEGER
|
|
|
|
Maximum time-to-live of entries. Unused entries will expire after
|
|
|
|
this period of time if there is no memory pressure on the pool (i.e.
|
|
|
|
when the number of entries in the pool is very small).
|
2008-07-02 08:22:48 +08:00
|
|
|
Measured in seconds.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2009-02-23 12:39:04 +08:00
|
|
|
TCP variables:
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
somaxconn - INTEGER
|
|
|
|
Limit of socket listen() backlog, known in userspace as SOMAXCONN.
|
|
|
|
Defaults to 128. See also tcp_max_syn_backlog for additional tuning
|
|
|
|
for TCP sockets.
|
|
|
|
|
|
|
|
tcp_abort_on_overflow - BOOLEAN
|
|
|
|
If listening service is too slow to accept new connections,
|
|
|
|
reset them. Default state is FALSE. It means that if overflow
|
|
|
|
occurred due to a burst, connection will recover. Enable this
|
|
|
|
option _only_ if you are really sure that listening daemon
|
|
|
|
cannot be tuned to accept connections faster. Enabling this
|
|
|
|
option can harm clients of your server.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_adv_win_scale - INTEGER
|
|
|
|
Count buffering overhead as bytes/2^tcp_adv_win_scale
|
|
|
|
(if tcp_adv_win_scale > 0) or bytes-bytes/2^(-tcp_adv_win_scale),
|
|
|
|
if it is <= 0.
|
2010-11-22 20:54:21 +08:00
|
|
|
Possible values are [-31, 31], inclusive.
|
2012-05-02 10:28:41 +08:00
|
|
|
Default: 1
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_allowed_congestion_control - STRING
|
|
|
|
Show/set the congestion control choices available to non-privileged
|
|
|
|
processes. The list is a subset of those listed in
|
|
|
|
tcp_available_congestion_control.
|
|
|
|
Default is "reno" and the default setting (tcp_congestion_control).
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_app_win - INTEGER
|
|
|
|
Reserve max(window/2^tcp_app_win, mss) of window for application
|
|
|
|
buffer. Value 0 is special, it means that nothing is reserved.
|
|
|
|
Default: 31
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_available_congestion_control - STRING
|
|
|
|
Shows the available congestion control choices that are registered.
|
|
|
|
More congestion control algorithms may be available as modules,
|
|
|
|
but not loaded.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-28 02:03:56 +08:00
|
|
|
tcp_base_mss - INTEGER
|
2008-07-11 07:50:26 +08:00
|
|
|
The initial value of search_low to be used by the packetization layer
|
|
|
|
Path MTU discovery (MTU probing). If MTU probing is enabled,
|
|
|
|
this is the initial MSS used by the connection.
|
2007-02-28 02:03:56 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_congestion_control - STRING
|
|
|
|
Set the congestion control algorithm to be used for new
|
|
|
|
connections. The algorithm "reno" is always available, but
|
|
|
|
additional choices may be available based on kernel configuration.
|
|
|
|
Default is set as part of kernel configuration.
|
2011-11-30 09:02:41 +08:00
|
|
|
For passive connections, the listener congestion control choice
|
|
|
|
is inherited.
|
|
|
|
[see setsockopt(listenfd, SOL_TCP, TCP_CONGESTION, "name" ...) ]
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_dsack - BOOLEAN
|
|
|
|
Allows TCP to send "duplicate" SACKs.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2012-05-02 21:30:03 +08:00
|
|
|
tcp_early_retrans - INTEGER
|
|
|
|
Enable Early Retransmit (ER), per RFC 5827. ER lowers the threshold
|
|
|
|
for triggering fast retransmit when the amount of outstanding data is
|
|
|
|
small and when no previously unsent data can be transmitted (such
|
tcp: Tail loss probe (TLP)
This patch series implement the Tail loss probe (TLP) algorithm described
in http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01. The
first patch implements the basic algorithm.
TLP's goal is to reduce tail latency of short transactions. It achieves
this by converting retransmission timeouts (RTOs) occuring due
to tail losses (losses at end of transactions) into fast recovery.
TLP transmits one packet in two round-trips when a connection is in
Open state and isn't receiving any ACKs. The transmitted packet, aka
loss probe, can be either new or a retransmission. When there is tail
loss, the ACK from a loss probe triggers FACK/early-retransmit based
fast recovery, thus avoiding a costly RTO. In the absence of loss,
there is no change in the connection state.
PTO stands for probe timeout. It is a timer event indicating
that an ACK is overdue and triggers a loss probe packet. The PTO value
is set to max(2*SRTT, 10ms) and is adjusted to account for delayed
ACK timer when there is only one oustanding packet.
TLP Algorithm
On transmission of new data in Open state:
-> packets_out > 1: schedule PTO in max(2*SRTT, 10ms).
-> packets_out == 1: schedule PTO in max(2*RTT, 1.5*RTT + 200ms)
-> PTO = min(PTO, RTO)
Conditions for scheduling PTO:
-> Connection is in Open state.
-> Connection is either cwnd limited or no new data to send.
-> Number of probes per tail loss episode is limited to one.
-> Connection is SACK enabled.
When PTO fires:
new_segment_exists:
-> transmit new segment.
-> packets_out++. cwnd remains same.
no_new_packet:
-> retransmit the last segment.
Its ACK triggers FACK or early retransmit based recovery.
ACK path:
-> rearm RTO at start of ACK processing.
-> reschedule PTO if need be.
In addition, the patch includes a small variation to the Early Retransmit
(ER) algorithm, such that ER and TLP together can in principle recover any
N-degree of tail loss through fast recovery. TLP is controlled by the same
sysctl as ER, tcp_early_retrans sysctl.
tcp_early_retrans==0; disables TLP and ER.
==1; enables RFC5827 ER.
==2; delayed ER.
==3; TLP and delayed ER. [DEFAULT]
==4; TLP only.
The TLP patch series have been extensively tested on Google Web servers.
It is most effective for short Web trasactions, where it reduced RTOs by 15%
and improved HTTP response time (average by 6%, 99th percentile by 10%).
The transmitted probes account for <0.5% of the overall transmissions.
Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-11 18:00:43 +08:00
|
|
|
that limited transmit could be used). Also controls the use of
|
2013-05-24 15:05:59 +08:00
|
|
|
Tail loss probe (TLP) that converts RTOs occurring due to tail
|
tcp: Tail loss probe (TLP)
This patch series implement the Tail loss probe (TLP) algorithm described
in http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01. The
first patch implements the basic algorithm.
TLP's goal is to reduce tail latency of short transactions. It achieves
this by converting retransmission timeouts (RTOs) occuring due
to tail losses (losses at end of transactions) into fast recovery.
TLP transmits one packet in two round-trips when a connection is in
Open state and isn't receiving any ACKs. The transmitted packet, aka
loss probe, can be either new or a retransmission. When there is tail
loss, the ACK from a loss probe triggers FACK/early-retransmit based
fast recovery, thus avoiding a costly RTO. In the absence of loss,
there is no change in the connection state.
PTO stands for probe timeout. It is a timer event indicating
that an ACK is overdue and triggers a loss probe packet. The PTO value
is set to max(2*SRTT, 10ms) and is adjusted to account for delayed
ACK timer when there is only one oustanding packet.
TLP Algorithm
On transmission of new data in Open state:
-> packets_out > 1: schedule PTO in max(2*SRTT, 10ms).
-> packets_out == 1: schedule PTO in max(2*RTT, 1.5*RTT + 200ms)
-> PTO = min(PTO, RTO)
Conditions for scheduling PTO:
-> Connection is in Open state.
-> Connection is either cwnd limited or no new data to send.
-> Number of probes per tail loss episode is limited to one.
-> Connection is SACK enabled.
When PTO fires:
new_segment_exists:
-> transmit new segment.
-> packets_out++. cwnd remains same.
no_new_packet:
-> retransmit the last segment.
Its ACK triggers FACK or early retransmit based recovery.
ACK path:
-> rearm RTO at start of ACK processing.
-> reschedule PTO if need be.
In addition, the patch includes a small variation to the Early Retransmit
(ER) algorithm, such that ER and TLP together can in principle recover any
N-degree of tail loss through fast recovery. TLP is controlled by the same
sysctl as ER, tcp_early_retrans sysctl.
tcp_early_retrans==0; disables TLP and ER.
==1; enables RFC5827 ER.
==2; delayed ER.
==3; TLP and delayed ER. [DEFAULT]
==4; TLP only.
The TLP patch series have been extensively tested on Google Web servers.
It is most effective for short Web trasactions, where it reduced RTOs by 15%
and improved HTTP response time (average by 6%, 99th percentile by 10%).
The transmitted probes account for <0.5% of the overall transmissions.
Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-11 18:00:43 +08:00
|
|
|
losses into fast recovery (draft-dukkipati-tcpm-tcp-loss-probe-01).
|
2012-05-02 21:30:03 +08:00
|
|
|
Possible values:
|
|
|
|
0 disables ER
|
|
|
|
1 enables ER
|
|
|
|
2 enables ER but delays fast recovery and fast retransmit
|
|
|
|
by a fourth of RTT. This mitigates connection falsely
|
|
|
|
recovers when network has a small degree of reordering
|
|
|
|
(less than 3 packets).
|
tcp: Tail loss probe (TLP)
This patch series implement the Tail loss probe (TLP) algorithm described
in http://tools.ietf.org/html/draft-dukkipati-tcpm-tcp-loss-probe-01. The
first patch implements the basic algorithm.
TLP's goal is to reduce tail latency of short transactions. It achieves
this by converting retransmission timeouts (RTOs) occuring due
to tail losses (losses at end of transactions) into fast recovery.
TLP transmits one packet in two round-trips when a connection is in
Open state and isn't receiving any ACKs. The transmitted packet, aka
loss probe, can be either new or a retransmission. When there is tail
loss, the ACK from a loss probe triggers FACK/early-retransmit based
fast recovery, thus avoiding a costly RTO. In the absence of loss,
there is no change in the connection state.
PTO stands for probe timeout. It is a timer event indicating
that an ACK is overdue and triggers a loss probe packet. The PTO value
is set to max(2*SRTT, 10ms) and is adjusted to account for delayed
ACK timer when there is only one oustanding packet.
TLP Algorithm
On transmission of new data in Open state:
-> packets_out > 1: schedule PTO in max(2*SRTT, 10ms).
-> packets_out == 1: schedule PTO in max(2*RTT, 1.5*RTT + 200ms)
-> PTO = min(PTO, RTO)
Conditions for scheduling PTO:
-> Connection is in Open state.
-> Connection is either cwnd limited or no new data to send.
-> Number of probes per tail loss episode is limited to one.
-> Connection is SACK enabled.
When PTO fires:
new_segment_exists:
-> transmit new segment.
-> packets_out++. cwnd remains same.
no_new_packet:
-> retransmit the last segment.
Its ACK triggers FACK or early retransmit based recovery.
ACK path:
-> rearm RTO at start of ACK processing.
-> reschedule PTO if need be.
In addition, the patch includes a small variation to the Early Retransmit
(ER) algorithm, such that ER and TLP together can in principle recover any
N-degree of tail loss through fast recovery. TLP is controlled by the same
sysctl as ER, tcp_early_retrans sysctl.
tcp_early_retrans==0; disables TLP and ER.
==1; enables RFC5827 ER.
==2; delayed ER.
==3; TLP and delayed ER. [DEFAULT]
==4; TLP only.
The TLP patch series have been extensively tested on Google Web servers.
It is most effective for short Web trasactions, where it reduced RTOs by 15%
and improved HTTP response time (average by 6%, 99th percentile by 10%).
The transmitted probes account for <0.5% of the overall transmissions.
Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-11 18:00:43 +08:00
|
|
|
3 enables delayed ER and TLP.
|
|
|
|
4 enables TLP only.
|
|
|
|
Default: 3
|
2012-05-02 21:30:03 +08:00
|
|
|
|
2011-02-03 07:39:58 +08:00
|
|
|
tcp_ecn - INTEGER
|
2012-11-28 17:53:10 +08:00
|
|
|
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.
|
2009-05-05 02:07:36 +08:00
|
|
|
Possible values are:
|
2012-11-28 17:53:10 +08:00
|
|
|
0 Disable ECN. Neither initiate nor accept ECN.
|
2013-01-09 20:21:30 +08:00
|
|
|
1 Enable ECN when requested by incoming connections and
|
|
|
|
also request ECN on outgoing connection attempts.
|
|
|
|
2 Enable ECN when requested by incoming connections
|
2012-11-28 17:53:10 +08:00
|
|
|
but do not request ECN on outgoing connections.
|
2009-05-05 02:07:36 +08:00
|
|
|
Default: 2
|
2006-11-10 08:37:26 +08:00
|
|
|
|
|
|
|
tcp_fack - BOOLEAN
|
|
|
|
Enable FACK congestion avoidance and fast retransmission.
|
|
|
|
The value is not used, if tcp_sack is not enabled.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
tcp_fin_timeout - INTEGER
|
2012-12-10 19:33:00 +08:00
|
|
|
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
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-28 02:10:55 +08:00
|
|
|
tcp_frto - INTEGER
|
2013-03-20 21:33:00 +08:00
|
|
|
Enables Forward RTO-Recovery (F-RTO) defined in RFC5682.
|
2007-09-21 02:35:26 +08:00
|
|
|
F-RTO is an enhanced recovery algorithm for TCP retransmission
|
2013-03-20 21:33:00 +08:00
|
|
|
timeouts. It is particularly beneficial in networks where the
|
|
|
|
RTT fluctuates (e.g., wireless). F-RTO is sender-side only
|
|
|
|
modification. It does not require any support from the peer.
|
|
|
|
|
|
|
|
By default it's enabled with a non-zero value. 0 disables F-RTO.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_keepalive_time - INTEGER
|
|
|
|
How often TCP sends out keepalive messages when keepalive is enabled.
|
|
|
|
Default: 2hours.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_keepalive_probes - INTEGER
|
|
|
|
How many keepalive probes TCP sends out, until it decides that the
|
|
|
|
connection is broken. Default value: 9.
|
|
|
|
|
|
|
|
tcp_keepalive_intvl - INTEGER
|
|
|
|
How frequently the probes are send out. Multiplied by
|
|
|
|
tcp_keepalive_probes it is time to kill not responding connection,
|
|
|
|
after probes started. Default value: 75sec i.e. connection
|
|
|
|
will be aborted after ~11 minutes of retries.
|
|
|
|
|
|
|
|
tcp_low_latency - BOOLEAN
|
|
|
|
If set, the TCP stack makes decisions that prefer lower
|
|
|
|
latency as opposed to higher throughput. By default, this
|
|
|
|
option is not set meaning that higher throughput is preferred.
|
|
|
|
An example of an application where this default should be
|
|
|
|
changed would be a Beowulf compute cluster.
|
|
|
|
Default: 0
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
tcp_max_orphans - INTEGER
|
|
|
|
Maximal number of TCP sockets not attached to any user file handle,
|
|
|
|
held by system. If this number is exceeded orphaned connections are
|
|
|
|
reset immediately and warning is printed. This limit exists
|
|
|
|
only to prevent simple DoS attacks, you _must_ not rely on this
|
|
|
|
or lower the limit artificially, but rather increase it
|
|
|
|
(probably, after increasing installed memory),
|
|
|
|
if network conditions require more than default value,
|
|
|
|
and tune network services to linger and kill such states
|
|
|
|
more aggressively. Let me to remind again: each orphan eats
|
|
|
|
up to ~64K of unswappable memory.
|
|
|
|
|
2011-02-20 05:52:41 +08:00
|
|
|
tcp_max_ssthresh - INTEGER
|
|
|
|
Limited Slow-Start for TCP with large congestion windows (cwnd) defined in
|
|
|
|
RFC3742. Limited slow-start is a mechanism to limit growth of the cwnd
|
|
|
|
on the region where cwnd is larger than tcp_max_ssthresh. TCP increases cwnd
|
|
|
|
by at most tcp_max_ssthresh segments, and by at least tcp_max_ssthresh/2
|
|
|
|
segments per RTT when the cwnd is above tcp_max_ssthresh.
|
|
|
|
If TCP connection increased cwnd to thousands (or tens of thousands) segments,
|
|
|
|
and thousands of packets were being dropped during slow-start, you can set
|
|
|
|
tcp_max_ssthresh to improve performance for new TCP connection.
|
|
|
|
Default: 0 (off)
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
tcp_max_syn_backlog - INTEGER
|
2011-12-06 05:39:41 +08:00
|
|
|
Maximal number of remembered connection requests, which have not
|
|
|
|
received an acknowledgment from connecting client.
|
|
|
|
The minimal value is 128 for low memory machines, and it will
|
|
|
|
increase in proportion to the memory of machine.
|
|
|
|
If server suffers from overload, try increasing this number.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_max_tw_buckets - INTEGER
|
|
|
|
Maximal number of timewait sockets held by system simultaneously.
|
|
|
|
If this number is exceeded time-wait socket is immediately destroyed
|
|
|
|
and warning is printed. This limit exists only to prevent
|
|
|
|
simple DoS attacks, you _must_ not lower the limit artificially,
|
|
|
|
but rather increase it (probably, after increasing installed memory),
|
|
|
|
if network conditions require more than default value.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_mem - vector of 3 INTEGERs: min, pressure, max
|
|
|
|
min: below this number of pages TCP is not bothered about its
|
|
|
|
memory appetite.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
pressure: when amount of memory allocated by TCP exceeds this number
|
|
|
|
of pages, TCP moderates its memory consumption and enters memory
|
|
|
|
pressure mode, which is exited when memory consumption falls
|
|
|
|
under "min".
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
max: number of pages allowed for queueing by all TCP sockets.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
Defaults are calculated at boot time from amount of available
|
|
|
|
memory.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-28 02:03:56 +08:00
|
|
|
tcp_moderate_rcvbuf - BOOLEAN
|
2008-07-11 07:50:26 +08:00
|
|
|
If set, TCP performs receive buffer auto-tuning, attempting to
|
2007-02-28 02:03:56 +08:00
|
|
|
automatically size the buffer (no greater than tcp_rmem[2]) to
|
|
|
|
match the size required by the path for full throughput. Enabled by
|
|
|
|
default.
|
|
|
|
|
|
|
|
tcp_mtu_probing - INTEGER
|
|
|
|
Controls TCP Packetization-Layer Path MTU Discovery. Takes three
|
|
|
|
values:
|
|
|
|
0 - Disabled
|
|
|
|
1 - Disabled by default, enabled when an ICMP black hole detected
|
|
|
|
2 - Always enabled, use initial MSS of tcp_base_mss.
|
|
|
|
|
|
|
|
tcp_no_metrics_save - BOOLEAN
|
|
|
|
By default, TCP saves various connection metrics in the route cache
|
|
|
|
when the connection closes, so that connections established in the
|
|
|
|
near future can use these to set initial conditions. Usually, this
|
|
|
|
increases overall performance, but may sometimes cause performance
|
2007-10-20 07:30:25 +08:00
|
|
|
degradation. If set, TCP will not cache metrics on closing
|
2007-02-28 02:03:56 +08:00
|
|
|
connections.
|
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_orphan_retries - INTEGER
|
2009-09-01 18:24:04 +08:00
|
|
|
This value influences the timeout of a locally closed TCP connection,
|
|
|
|
when RTO retransmissions remain unacknowledged.
|
|
|
|
See tcp_retries2 for more details.
|
|
|
|
|
2011-07-09 00:31:31 +08:00
|
|
|
The default value is 8.
|
2009-09-01 18:24:04 +08:00
|
|
|
If your machine is a loaded WEB server,
|
2006-11-10 08:37:26 +08:00
|
|
|
you should think about lowering this value, such sockets
|
|
|
|
may consume significant resources. Cf. tcp_max_orphans.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
tcp_reordering - INTEGER
|
|
|
|
Maximal reordering of packets in a TCP stream.
|
2009-02-23 12:39:04 +08:00
|
|
|
Default: 3
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
tcp_retrans_collapse - BOOLEAN
|
|
|
|
Bug-to-bug compatibility with some broken printers.
|
|
|
|
On retransmit try to send bigger packets to work around bugs in
|
|
|
|
certain TCP stacks.
|
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_retries1 - INTEGER
|
2009-09-01 18:24:04 +08:00
|
|
|
This value influences the time, after which TCP decides, that
|
|
|
|
something is wrong due to unacknowledged RTO retransmissions,
|
|
|
|
and reports this suspicion to the network layer.
|
|
|
|
See tcp_retries2 for more details.
|
|
|
|
|
|
|
|
RFC 1122 recommends at least 3 retransmissions, which is the
|
|
|
|
default.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_retries2 - INTEGER
|
2009-09-01 18:24:04 +08:00
|
|
|
This value influences the timeout of an alive TCP connection,
|
|
|
|
when RTO retransmissions remain unacknowledged.
|
|
|
|
Given a value of N, a hypothetical TCP connection following
|
|
|
|
exponential backoff with an initial RTO of TCP_RTO_MIN would
|
|
|
|
retransmit N times before killing the connection at the (N+1)th RTO.
|
|
|
|
|
|
|
|
The default value of 15 yields a hypothetical timeout of 924.6
|
|
|
|
seconds and is a lower bound for the effective timeout.
|
|
|
|
TCP will effectively time out at the first RTO which exceeds the
|
|
|
|
hypothetical timeout.
|
|
|
|
|
|
|
|
RFC 1122 recommends at least 100 seconds for the timeout,
|
|
|
|
which corresponds to a value of at least 8.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_rfc1337 - BOOLEAN
|
|
|
|
If set, the TCP stack behaves conforming to RFC1337. If unset,
|
|
|
|
we are not conforming to RFC, but prevent TCP TIME_WAIT
|
|
|
|
assassination.
|
|
|
|
Default: 0
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
tcp_rmem - vector of 3 INTEGERs: min, default, max
|
|
|
|
min: Minimal size of receive buffer used by TCP sockets.
|
|
|
|
It is guaranteed to each TCP socket, even under moderate memory
|
|
|
|
pressure.
|
2011-06-22 05:18:13 +08:00
|
|
|
Default: 1 page
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-07-11 07:47:41 +08:00
|
|
|
default: initial size of receive buffer used by TCP sockets.
|
2005-04-17 06:20:36 +08:00
|
|
|
This value overrides net.core.rmem_default used by other protocols.
|
|
|
|
Default: 87380 bytes. This value results in window of 65535 with
|
|
|
|
default setting of tcp_adv_win_scale and tcp_app_win:0 and a bit
|
|
|
|
less for default tcp_app_win. See below about these variables.
|
|
|
|
|
|
|
|
max: maximal size of receive buffer allowed for automatically
|
|
|
|
selected receiver buffers for TCP socket. This value does not override
|
2008-07-11 07:47:41 +08:00
|
|
|
net.core.rmem_max. Calling setsockopt() with SO_RCVBUF disables
|
|
|
|
automatic tuning of that socket's receive buffer size, in which
|
|
|
|
case this value is ignored.
|
2012-05-02 10:28:41 +08:00
|
|
|
Default: between 87380B and 6MB, depending on RAM size.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_sack - BOOLEAN
|
|
|
|
Enable select acknowledgments (SACKS).
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_slow_start_after_idle - BOOLEAN
|
|
|
|
If set, provide RFC2861 behavior and time out the congestion
|
|
|
|
window after an idle period. An idle period is defined at
|
|
|
|
the current RTO. If unset, the congestion window will not
|
|
|
|
be timed out after an idle period.
|
|
|
|
Default: 1
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_stdurg - BOOLEAN
|
2008-07-11 07:50:26 +08:00
|
|
|
Use the Host requirements interpretation of the TCP urgent pointer field.
|
2006-11-10 08:37:26 +08:00
|
|
|
Most hosts use the older BSD interpretation, so if you turn this on
|
|
|
|
Linux might not communicate correctly with them.
|
|
|
|
Default: FALSE
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_synack_retries - INTEGER
|
|
|
|
Number of times SYNACKs for a passive TCP connection attempt will
|
|
|
|
be retransmitted. Should not be higher than 255. Default value
|
2012-08-31 10:48:31 +08:00
|
|
|
is 5, which corresponds to 31seconds till the last retransmission
|
|
|
|
with the current initial RTO of 1second. With this the final timeout
|
|
|
|
for a passive TCP connection will happen after 63seconds.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_syncookies - BOOLEAN
|
2013-06-21 15:18:32 +08:00
|
|
|
Only valid when the kernel was compiled with CONFIG_SYN_COOKIES
|
2006-11-10 08:37:26 +08:00
|
|
|
Send out syncookies when the syn backlog queue of a socket
|
2008-07-11 07:50:26 +08:00
|
|
|
overflows. This is to prevent against the common 'SYN flood attack'
|
2013-06-21 15:18:32 +08:00
|
|
|
Default: 1
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
Note, that syncookies is fallback facility.
|
|
|
|
It MUST NOT be used to help highly loaded servers to stand
|
2008-07-11 07:50:26 +08:00
|
|
|
against legal connection rate. If you see SYN flood warnings
|
2006-11-10 08:37:26 +08:00
|
|
|
in your logs, but investigation shows that they occur
|
|
|
|
because of overload with legal connections, you should tune
|
|
|
|
another parameters until this warning disappear.
|
|
|
|
See: tcp_max_syn_backlog, tcp_synack_retries, tcp_abort_on_overflow.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
syncookies seriously violate TCP protocol, do not allow
|
|
|
|
to use TCP extensions, can result in serious degradation
|
|
|
|
of some services (f.e. SMTP relaying), visible not by you,
|
|
|
|
but your clients and relays, contacting you. While you see
|
2008-07-11 07:50:26 +08:00
|
|
|
SYN flood warnings in logs not being really flooded, your server
|
2006-11-10 08:37:26 +08:00
|
|
|
is seriously misconfigured.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2012-07-19 14:43:09 +08:00
|
|
|
tcp_fastopen - INTEGER
|
|
|
|
Enable TCP Fast Open feature (draft-ietf-tcpm-fastopen) to send data
|
|
|
|
in the opening SYN packet. To use this feature, the client application
|
2012-08-31 20:29:11 +08:00
|
|
|
must use sendmsg() or sendto() with MSG_FASTOPEN flag rather than
|
|
|
|
connect() to perform a TCP handshake automatically.
|
|
|
|
|
|
|
|
The values (bitmap) are
|
|
|
|
1: Enables sending data in the opening SYN on the client.
|
|
|
|
2: Enables TCP Fast Open on the server side, i.e., allowing data in
|
|
|
|
a SYN packet to be accepted and passed to the application before
|
|
|
|
3-way hand shake finishes.
|
|
|
|
4: Send data in the opening SYN regardless of cookie availability and
|
|
|
|
without a cookie option.
|
|
|
|
0x100: Accept SYN data w/o validating the cookie.
|
|
|
|
0x200: Accept data-in-SYN w/o any cookie option present.
|
|
|
|
0x400/0x800: Enable Fast Open on all listeners regardless of the
|
|
|
|
TCP_FASTOPEN socket option. The two different flags designate two
|
|
|
|
different ways of setting max_qlen without the TCP_FASTOPEN socket
|
|
|
|
option.
|
2012-07-19 14:43:09 +08:00
|
|
|
|
|
|
|
Default: 0
|
|
|
|
|
2012-08-31 20:29:11 +08:00
|
|
|
Note that the client & server side Fast Open flags (1 and 2
|
|
|
|
respectively) must be also enabled before the rest of flags can take
|
|
|
|
effect.
|
|
|
|
|
|
|
|
See include/net/tcp.h and the code for more details.
|
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_syn_retries - INTEGER
|
|
|
|
Number of times initial SYNs for an active TCP connection attempt
|
|
|
|
will be retransmitted. Should not be higher than 255. Default value
|
2013-01-03 15:50:29 +08:00
|
|
|
is 6, which corresponds to 63seconds till the last retransmission
|
2012-08-31 10:48:31 +08:00
|
|
|
with the current initial RTO of 1second. With this the final timeout
|
|
|
|
for an active TCP connection attempt will happen after 127seconds.
|
2006-11-10 08:37:26 +08:00
|
|
|
|
|
|
|
tcp_timestamps - BOOLEAN
|
|
|
|
Enable timestamps as defined in RFC1323.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
tcp_tso_win_divisor - INTEGER
|
2006-11-10 08:37:26 +08:00
|
|
|
This allows control over what percentage of the congestion window
|
|
|
|
can be consumed by a single TSO frame.
|
|
|
|
The setting of this parameter is a choice between burstiness and
|
|
|
|
building larger TSO frames.
|
|
|
|
Default: 3
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_tw_recycle - BOOLEAN
|
|
|
|
Enable fast recycling TIME-WAIT sockets. Default value is 0.
|
|
|
|
It should not be changed without advice/request of technical
|
|
|
|
experts.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_tw_reuse - BOOLEAN
|
|
|
|
Allow to reuse TIME-WAIT sockets for new connections when it is
|
|
|
|
safe from protocol viewpoint. Default value is 0.
|
|
|
|
It should not be changed without advice/request of technical
|
|
|
|
experts.
|
2006-11-10 08:35:15 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_window_scaling - BOOLEAN
|
|
|
|
Enable window scaling as defined in RFC1323.
|
2006-11-10 08:32:06 +08:00
|
|
|
|
2006-11-10 08:37:26 +08:00
|
|
|
tcp_wmem - vector of 3 INTEGERs: min, default, max
|
2008-07-11 07:47:41 +08:00
|
|
|
min: Amount of memory reserved for send buffers for TCP sockets.
|
2006-11-10 08:37:26 +08:00
|
|
|
Each TCP socket has rights to use it due to fact of its birth.
|
2011-06-22 05:18:13 +08:00
|
|
|
Default: 1 page
|
2005-06-24 03:22:36 +08:00
|
|
|
|
2008-07-11 07:47:41 +08:00
|
|
|
default: initial size of send buffer used by TCP sockets. This
|
|
|
|
value overrides net.core.wmem_default used by other protocols.
|
|
|
|
It is usually lower than net.core.wmem_default.
|
2006-11-10 08:37:26 +08:00
|
|
|
Default: 16K
|
|
|
|
|
2008-07-11 07:47:41 +08:00
|
|
|
max: Maximal amount of memory allowed for automatically tuned
|
|
|
|
send buffers for TCP sockets. This value does not override
|
|
|
|
net.core.wmem_max. Calling setsockopt() with SO_SNDBUF disables
|
|
|
|
automatic tuning of that socket's send buffer size, in which case
|
|
|
|
this value is ignored.
|
|
|
|
Default: between 64K and 4MB, depending on RAM size.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
tcp: TCP_NOTSENT_LOWAT socket option
Idea of this patch is to add optional limitation of number of
unsent bytes in TCP sockets, to reduce usage of kernel memory.
TCP receiver might announce a big window, and TCP sender autotuning
might allow a large amount of bytes in write queue, but this has little
performance impact if a large part of this buffering is wasted :
Write queue needs to be large only to deal with large BDP, not
necessarily to cope with scheduling delays (incoming ACKS make room
for the application to queue more bytes)
For most workloads, using a value of 128 KB or less is OK to give
applications enough time to react to POLLOUT events in time
(or being awaken in a blocking sendmsg())
This patch adds two ways to set the limit :
1) Per socket option TCP_NOTSENT_LOWAT
2) A sysctl (/proc/sys/net/ipv4/tcp_notsent_lowat) for sockets
not using TCP_NOTSENT_LOWAT socket option (or setting a zero value)
Default value being UINT_MAX (0xFFFFFFFF), meaning this has no effect.
This changes poll()/select()/epoll() to report POLLOUT
only if number of unsent bytes is below tp->nosent_lowat
Note this might increase number of sendmsg()/sendfile() calls
when using non blocking sockets,
and increase number of context switches for blocking sockets.
Note this is not related to SO_SNDLOWAT (as SO_SNDLOWAT is
defined as :
Specify the minimum number of bytes in the buffer until
the socket layer will pass the data to the protocol)
Tested:
netperf sessions, and watching /proc/net/protocols "memory" column for TCP
With 200 concurrent netperf -t TCP_STREAM sessions, amount of kernel memory
used by TCP buffers shrinks by ~55 % (20567 pages instead of 45458)
lpq83:~# echo -1 >/proc/sys/net/ipv4/tcp_notsent_lowat
lpq83:~# (super_netperf 200 -t TCP_STREAM -H remote -l 90 &); sleep 60 ; grep TCP /proc/net/protocols
TCPv6 1880 2 45458 no 208 yes ipv6 y y y y y y y y y y y y y n y y y y y
TCP 1696 508 45458 no 208 yes kernel y y y y y y y y y y y y y n y y y y y
lpq83:~# echo 131072 >/proc/sys/net/ipv4/tcp_notsent_lowat
lpq83:~# (super_netperf 200 -t TCP_STREAM -H remote -l 90 &); sleep 60 ; grep TCP /proc/net/protocols
TCPv6 1880 2 20567 no 208 yes ipv6 y y y y y y y y y y y y y n y y y y y
TCP 1696 508 20567 no 208 yes kernel y y y y y y y y y y y y y n y y y y y
Using 128KB has no bad effect on the throughput or cpu usage
of a single flow, although there is an increase of context switches.
A bonus is that we hold socket lock for a shorter amount
of time and should improve latencies of ACK processing.
lpq83:~# echo -1 >/proc/sys/net/ipv4/tcp_notsent_lowat
lpq83:~# perf stat -e context-switches ./netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3
OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : +/-2.500% @ 99% conf.
Local Remote Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service
Send Socket Recv Socket Send Time Units CPU CPU CPU CPU Service Service Demand
Size Size Size (sec) Util Util Util Util Demand Demand Units
Final Final % Method % Method
1651584 6291456 16384 20.00 17447.90 10^6bits/s 3.13 S -1.00 U 0.353 -1.000 usec/KB
Performance counter stats for './netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3':
412,514 context-switches
200.034645535 seconds time elapsed
lpq83:~# echo 131072 >/proc/sys/net/ipv4/tcp_notsent_lowat
lpq83:~# perf stat -e context-switches ./netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3
OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : +/-2.500% @ 99% conf.
Local Remote Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service
Send Socket Recv Socket Send Time Units CPU CPU CPU CPU Service Service Demand
Size Size Size (sec) Util Util Util Util Demand Demand Units
Final Final % Method % Method
1593240 6291456 16384 20.00 17321.16 10^6bits/s 3.35 S -1.00 U 0.381 -1.000 usec/KB
Performance counter stats for './netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3':
2,675,818 context-switches
200.029651391 seconds time elapsed
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-By: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-23 11:27:07 +08:00
|
|
|
tcp_notsent_lowat - UNSIGNED INTEGER
|
|
|
|
A TCP socket can control the amount of unsent bytes in its write queue,
|
|
|
|
thanks to TCP_NOTSENT_LOWAT socket option. poll()/select()/epoll()
|
|
|
|
reports POLLOUT events if the amount of unsent bytes is below a per
|
|
|
|
socket value, and if the write queue is not full. sendmsg() will
|
|
|
|
also not add new buffers if the limit is hit.
|
|
|
|
|
|
|
|
This global variable controls the amount of unsent data for
|
|
|
|
sockets not using TCP_NOTSENT_LOWAT. For these sockets, a change
|
|
|
|
to the global variable has immediate effect.
|
|
|
|
|
|
|
|
Default: UINT_MAX (0xFFFFFFFF)
|
|
|
|
|
2006-03-21 14:40:29 +08:00
|
|
|
tcp_workaround_signed_windows - BOOLEAN
|
|
|
|
If set, assume no receipt of a window scaling option means the
|
|
|
|
remote TCP is broken and treats the window as a signed quantity.
|
|
|
|
If unset, assume the remote TCP is not broken even if we do
|
|
|
|
not receive a window scaling option from them.
|
|
|
|
Default: 0
|
|
|
|
|
2007-03-09 01:57:35 +08:00
|
|
|
tcp_dma_copybreak - INTEGER
|
|
|
|
Lower limit, in bytes, of the size of socket reads that will be
|
|
|
|
offloaded to a DMA copy engine, if one is present in the system
|
|
|
|
and CONFIG_NET_DMA is enabled.
|
|
|
|
Default: 4096
|
|
|
|
|
2010-02-18 10:47:01 +08:00
|
|
|
tcp_thin_linear_timeouts - BOOLEAN
|
|
|
|
Enable dynamic triggering of linear timeouts for thin streams.
|
|
|
|
If set, a check is performed upon retransmission by timeout to
|
|
|
|
determine if the stream is thin (less than 4 packets in flight).
|
|
|
|
As long as the stream is found to be thin, up to 6 linear
|
|
|
|
timeouts may be performed before exponential backoff mode is
|
|
|
|
initiated. This improves retransmission latency for
|
|
|
|
non-aggressive thin streams, often found to be time-dependent.
|
|
|
|
For more information on thin streams, see
|
|
|
|
Documentation/networking/tcp-thin.txt
|
|
|
|
Default: 0
|
|
|
|
|
2010-02-18 12:48:19 +08:00
|
|
|
tcp_thin_dupack - BOOLEAN
|
|
|
|
Enable dynamic triggering of retransmissions after one dupACK
|
|
|
|
for thin streams. If set, a check is performed upon reception
|
|
|
|
of a dupACK to determine if the stream is thin (less than 4
|
|
|
|
packets in flight). As long as the stream is found to be thin,
|
|
|
|
data is retransmitted on the first received dupACK. This
|
|
|
|
improves retransmission latency for non-aggressive thin
|
|
|
|
streams, often found to be time-dependent.
|
|
|
|
For more information on thin streams, see
|
|
|
|
Documentation/networking/tcp-thin.txt
|
|
|
|
Default: 0
|
|
|
|
|
tcp: TCP Small Queues
This introduce TSQ (TCP Small Queues)
TSQ goal is to reduce number of TCP packets in xmit queues (qdisc &
device queues), to reduce RTT and cwnd bias, part of the bufferbloat
problem.
sk->sk_wmem_alloc not allowed to grow above a given limit,
allowing no more than ~128KB [1] per tcp socket in qdisc/dev layers at a
given time.
TSO packets are sized/capped to half the limit, so that we have two
TSO packets in flight, allowing better bandwidth use.
As a side effect, setting the limit to 40000 automatically reduces the
standard gso max limit (65536) to 40000/2 : It can help to reduce
latencies of high prio packets, having smaller TSO packets.
This means we divert sock_wfree() to a tcp_wfree() handler, to
queue/send following frames when skb_orphan() [2] is called for the
already queued skbs.
Results on my dev machines (tg3/ixgbe nics) are really impressive,
using standard pfifo_fast, and with or without TSO/GSO.
Without reduction of nominal bandwidth, we have reduction of buffering
per bulk sender :
< 1ms on Gbit (instead of 50ms with TSO)
< 8ms on 100Mbit (instead of 132 ms)
I no longer have 4 MBytes backlogged in qdisc by a single netperf
session, and both side socket autotuning no longer use 4 Mbytes.
As skb destructor cannot restart xmit itself ( as qdisc lock might be
taken at this point ), we delegate the work to a tasklet. We use one
tasklest per cpu for performance reasons.
If tasklet finds a socket owned by the user, it sets TSQ_OWNED flag.
This flag is tested in a new protocol method called from release_sock(),
to eventually send new segments.
[1] New /proc/sys/net/ipv4/tcp_limit_output_bytes tunable
[2] skb_orphan() is usually called at TX completion time,
but some drivers call it in their start_xmit() handler.
These drivers should at least use BQL, or else a single TCP
session can still fill the whole NIC TX ring, since TSQ will
have no effect.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Dave Taht <dave.taht@bufferbloat.net>
Cc: Tom Herbert <therbert@google.com>
Cc: Matt Mathis <mattmathis@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Nandita Dukkipati <nanditad@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-11 13:50:31 +08:00
|
|
|
tcp_limit_output_bytes - INTEGER
|
|
|
|
Controls TCP Small Queue limit per tcp socket.
|
|
|
|
TCP bulk sender tends to increase packets in flight until it
|
|
|
|
gets losses notifications. With SNDBUF autotuning, this can
|
|
|
|
result in a large amount of packets queued in qdisc/device
|
|
|
|
on the local machine, hurting latency of other flows, for
|
|
|
|
typical pfifo_fast qdiscs.
|
|
|
|
tcp_limit_output_bytes limits the number of bytes on qdisc
|
|
|
|
or device to reduce artificial RTT/cwnd and reduce bufferbloat.
|
|
|
|
Note: For GSO/TSO enabled flows, we try to have at least two
|
|
|
|
packets in flight. Reducing tcp_limit_output_bytes might also
|
|
|
|
reduce the size of individual GSO packet (64KB being the max)
|
|
|
|
Default: 131072
|
|
|
|
|
2012-07-17 16:13:05 +08:00
|
|
|
tcp_challenge_ack_limit - INTEGER
|
|
|
|
Limits number of Challenge ACK sent per second, as recommended
|
|
|
|
in RFC 5961 (Improving TCP's Robustness to Blind In-Window Attacks)
|
|
|
|
Default: 100
|
|
|
|
|
2007-12-31 16:29:24 +08:00
|
|
|
UDP variables:
|
|
|
|
|
|
|
|
udp_mem - vector of 3 INTEGERs: min, pressure, max
|
|
|
|
Number of pages allowed for queueing by all UDP sockets.
|
|
|
|
|
|
|
|
min: Below this number of pages UDP is not bothered about its
|
|
|
|
memory appetite. When amount of memory allocated by UDP exceeds
|
|
|
|
this number, UDP 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 UDP sockets.
|
|
|
|
|
|
|
|
Default is calculated at boot time from amount of available memory.
|
|
|
|
|
|
|
|
udp_rmem_min - INTEGER
|
|
|
|
Minimal size of receive buffer used by UDP sockets in moderation.
|
|
|
|
Each UDP socket is able to use the size for receiving data, even if
|
|
|
|
total pages of UDP sockets exceed udp_mem pressure. The unit is byte.
|
2011-06-22 05:18:13 +08:00
|
|
|
Default: 1 page
|
2007-12-31 16:29:24 +08:00
|
|
|
|
|
|
|
udp_wmem_min - INTEGER
|
|
|
|
Minimal size of send buffer used by UDP sockets in moderation.
|
|
|
|
Each UDP socket is able to use the size for sending data, even if
|
|
|
|
total pages of UDP sockets exceed udp_mem pressure. The unit is byte.
|
2011-06-22 05:18:13 +08:00
|
|
|
Default: 1 page
|
2007-12-31 16:29:24 +08:00
|
|
|
|
2006-08-04 07:45:49 +08:00
|
|
|
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
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
IP Variables:
|
|
|
|
|
|
|
|
ip_local_port_range - 2 INTEGERS
|
|
|
|
Defines the local port range that is used by TCP and UDP to
|
2009-02-23 12:39:04 +08:00
|
|
|
choose the local port. The first number is the first, the
|
2012-04-03 16:41:40 +08:00
|
|
|
second the last local port number. The default values are
|
|
|
|
32768 and 61000 respectively.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2010-05-05 08:27:06 +08:00
|
|
|
ip_local_reserved_ports - list of comma separated ranges
|
|
|
|
Specify the ports which are reserved for known third-party
|
|
|
|
applications. These ports will not be used by automatic port
|
|
|
|
assignments (e.g. when calling connect() or bind() with port
|
|
|
|
number 0). Explicit port allocation behavior is unchanged.
|
|
|
|
|
|
|
|
The format used for both input and output is a comma separated
|
|
|
|
list of ranges (e.g. "1,2-4,10-10" for ports 1, 2, 3, 4 and
|
|
|
|
10). Writing to the file will clear all previously reserved
|
|
|
|
ports and update the current list with the one given in the
|
|
|
|
input.
|
|
|
|
|
|
|
|
Note that ip_local_port_range and ip_local_reserved_ports
|
|
|
|
settings are independent and both are considered by the kernel
|
|
|
|
when determining which ports are available for automatic port
|
|
|
|
assignments.
|
|
|
|
|
|
|
|
You can reserve ports which are not in the current
|
|
|
|
ip_local_port_range, e.g.:
|
|
|
|
|
|
|
|
$ cat /proc/sys/net/ipv4/ip_local_port_range
|
|
|
|
32000 61000
|
|
|
|
$ cat /proc/sys/net/ipv4/ip_local_reserved_ports
|
|
|
|
8080,9148
|
|
|
|
|
|
|
|
although this is redundant. However such a setting is useful
|
|
|
|
if later the port range is changed to a value that will
|
|
|
|
include the reserved ports.
|
|
|
|
|
|
|
|
Default: Empty
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
ip_nonlocal_bind - BOOLEAN
|
|
|
|
If set, allows processes to bind() to non-local IP addresses,
|
|
|
|
which can be quite useful - but may break some applications.
|
|
|
|
Default: 0
|
|
|
|
|
|
|
|
ip_dynaddr - BOOLEAN
|
|
|
|
If set non-zero, enables support for dynamic addresses.
|
|
|
|
If set to a non-zero value larger than 1, a kernel log
|
|
|
|
message will be printed when dynamic address rewriting
|
|
|
|
occurs.
|
|
|
|
Default: 0
|
|
|
|
|
2013-06-11 18:54:39 +08:00
|
|
|
ip_early_demux - BOOLEAN
|
|
|
|
Optimize input packet processing down to one demux for
|
|
|
|
certain kinds of local sockets. Currently we only do this
|
|
|
|
for established TCP sockets.
|
|
|
|
|
|
|
|
It may add an additional cost for pure routing workloads that
|
|
|
|
reduces overall throughput, in such case you should disable it.
|
|
|
|
Default: 1
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
icmp_echo_ignore_all - BOOLEAN
|
2005-10-04 07:07:30 +08:00
|
|
|
If set non-zero, then the kernel will ignore all ICMP ECHO
|
|
|
|
requests sent to it.
|
|
|
|
Default: 0
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
icmp_echo_ignore_broadcasts - BOOLEAN
|
2005-10-04 07:07:30 +08:00
|
|
|
If set non-zero, then the kernel will ignore all ICMP ECHO and
|
|
|
|
TIMESTAMP requests sent to it via broadcast/multicast.
|
|
|
|
Default: 1
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
icmp_ratelimit - INTEGER
|
|
|
|
Limit the maximal rates for sending ICMP packets whose type matches
|
|
|
|
icmp_ratemask (see below) to specific targets.
|
2008-07-02 10:29:07 +08:00
|
|
|
0 to disable any limiting,
|
|
|
|
otherwise the minimal space between responses in milliseconds.
|
|
|
|
Default: 1000
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
icmp_ratemask - INTEGER
|
|
|
|
Mask made of ICMP types for which rates are being limited.
|
|
|
|
Significant bits: IHGFEDCBA9876543210
|
|
|
|
Default mask: 0000001100000011000 (6168)
|
|
|
|
|
|
|
|
Bit definitions (see include/linux/icmp.h):
|
|
|
|
0 Echo Reply
|
|
|
|
3 Destination Unreachable *
|
|
|
|
4 Source Quench *
|
|
|
|
5 Redirect
|
|
|
|
8 Echo Request
|
|
|
|
B Time Exceeded *
|
|
|
|
C Parameter Problem *
|
|
|
|
D Timestamp Request
|
|
|
|
E Timestamp Reply
|
|
|
|
F Info Request
|
|
|
|
G Info Reply
|
|
|
|
H Address Mask Request
|
|
|
|
I Address Mask Reply
|
|
|
|
|
|
|
|
* These are rate limited by default (see default mask above)
|
|
|
|
|
|
|
|
icmp_ignore_bogus_error_responses - BOOLEAN
|
|
|
|
Some routers violate RFC1122 by sending bogus responses to broadcast
|
|
|
|
frames. Such violations are normally logged via a kernel warning.
|
|
|
|
If this is set to TRUE, the kernel will not give such warnings, which
|
|
|
|
will avoid log file clutter.
|
2013-06-08 04:16:19 +08:00
|
|
|
Default: 1
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-02-03 09:02:25 +08:00
|
|
|
icmp_errors_use_inbound_ifaddr - BOOLEAN
|
|
|
|
|
|
|
|
If zero, icmp error messages are sent with the primary address of
|
|
|
|
the exiting interface.
|
2009-02-23 12:39:04 +08:00
|
|
|
|
2006-02-03 09:02:25 +08:00
|
|
|
If non-zero, the message will be sent with the primary address of
|
|
|
|
the interface that received the packet that caused the icmp error.
|
|
|
|
This is the behaviour network many administrators will expect from
|
|
|
|
a router. And it can make debugging complicated network layouts
|
2009-02-23 12:39:04 +08:00
|
|
|
much easier.
|
2006-02-03 09:02:25 +08:00
|
|
|
|
|
|
|
Note that if no primary address exists for the interface selected,
|
|
|
|
then the primary address of the first non-loopback interface that
|
2006-10-04 04:54:15 +08:00
|
|
|
has one will be used regardless of this setting.
|
2006-02-03 09:02:25 +08:00
|
|
|
|
|
|
|
Default: 0
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
igmp_max_memberships - INTEGER
|
|
|
|
Change the maximum number of multicast groups we can subscribe to.
|
|
|
|
Default: 20
|
|
|
|
|
2010-11-15 13:41:31 +08:00
|
|
|
Theoretical maximum value is bounded by having to send a membership
|
|
|
|
report in a single datagram (i.e. the report can't span multiple
|
|
|
|
datagrams, or risk confusing the switch and leaving groups you don't
|
|
|
|
intend to).
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2010-11-15 13:41:31 +08:00
|
|
|
The number of supported groups 'M' is bounded by the number of group
|
|
|
|
report entries you can fit into a single datagram of 65535 bytes.
|
|
|
|
|
|
|
|
M = 65536-sizeof (ip header)/(sizeof(Group record))
|
|
|
|
|
|
|
|
Group records are variable length, with a minimum of 12 bytes.
|
|
|
|
So net.ipv4.igmp_max_memberships should not be set higher than:
|
|
|
|
|
|
|
|
(65536-24) / 12 = 5459
|
|
|
|
|
|
|
|
The value 5459 assumes no IP header options, so in practice
|
|
|
|
this number may be lower.
|
|
|
|
|
|
|
|
conf/interface/* changes special settings per interface (where
|
|
|
|
"interface" is the name of your network interface)
|
|
|
|
|
|
|
|
conf/all/* is special, changes the settings for all interfaces
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
log_martians - BOOLEAN
|
|
|
|
Log packets with impossible addresses to kernel log.
|
|
|
|
log_martians for the interface will be enabled if at least one of
|
|
|
|
conf/{all,interface}/log_martians is set to TRUE,
|
|
|
|
it will be disabled otherwise
|
|
|
|
|
|
|
|
accept_redirects - BOOLEAN
|
|
|
|
Accept ICMP redirect messages.
|
|
|
|
accept_redirects for the interface will be enabled if:
|
2009-02-23 12:39:04 +08:00
|
|
|
- both conf/{all,interface}/accept_redirects are TRUE in the case
|
|
|
|
forwarding for the interface is enabled
|
2005-04-17 06:20:36 +08:00
|
|
|
or
|
2009-02-23 12:39:04 +08:00
|
|
|
- at least one of conf/{all,interface}/accept_redirects is TRUE in the
|
|
|
|
case forwarding for the interface is disabled
|
2005-04-17 06:20:36 +08:00
|
|
|
accept_redirects for the interface will be disabled otherwise
|
|
|
|
default TRUE (host)
|
|
|
|
FALSE (router)
|
|
|
|
|
|
|
|
forwarding - BOOLEAN
|
|
|
|
Enable IP forwarding on this interface.
|
|
|
|
|
|
|
|
mc_forwarding - BOOLEAN
|
|
|
|
Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE
|
|
|
|
and a multicast routing daemon is required.
|
2009-02-23 12:39:04 +08:00
|
|
|
conf/all/mc_forwarding must also be set to TRUE to enable multicast
|
|
|
|
routing for the interface
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
medium_id - INTEGER
|
|
|
|
Integer value used to differentiate the devices by the medium they
|
|
|
|
are attached to. Two devices can have different id values when
|
|
|
|
the broadcast packets are received only on one of them.
|
|
|
|
The default value 0 means that the device is the only interface
|
|
|
|
to its medium, value of -1 means that medium is not known.
|
2009-02-23 12:39:04 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
Currently, it is used to change the proxy_arp behavior:
|
|
|
|
the proxy_arp feature is enabled for packets forwarded between
|
|
|
|
two devices attached to different media.
|
|
|
|
|
|
|
|
proxy_arp - BOOLEAN
|
|
|
|
Do proxy arp.
|
|
|
|
proxy_arp for the interface will be enabled if at least one of
|
|
|
|
conf/{all,interface}/proxy_arp is set to TRUE,
|
|
|
|
it will be disabled otherwise
|
|
|
|
|
2010-01-05 13:50:47 +08:00
|
|
|
proxy_arp_pvlan - BOOLEAN
|
|
|
|
Private VLAN proxy arp.
|
|
|
|
Basically allow proxy arp replies back to the same interface
|
|
|
|
(from which the ARP request/solicitation was received).
|
|
|
|
|
|
|
|
This is done to support (ethernet) switch features, like RFC
|
|
|
|
3069, where the individual ports are NOT allowed to
|
|
|
|
communicate with each other, but they are allowed to talk to
|
|
|
|
the upstream router. As described in RFC 3069, it is possible
|
|
|
|
to allow these hosts to communicate through the upstream
|
|
|
|
router by proxy_arp'ing. Don't need to be used together with
|
|
|
|
proxy_arp.
|
|
|
|
|
|
|
|
This technology is known by different names:
|
|
|
|
In RFC 3069 it is called VLAN Aggregation.
|
|
|
|
Cisco and Allied Telesyn call it Private VLAN.
|
|
|
|
Hewlett-Packard call it Source-Port filtering or port-isolation.
|
|
|
|
Ericsson call it MAC-Forced Forwarding (RFC Draft).
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
shared_media - BOOLEAN
|
|
|
|
Send(router) or accept(host) RFC1620 shared media redirects.
|
|
|
|
Overrides ip_secure_redirects.
|
|
|
|
shared_media for the interface will be enabled if at least one of
|
|
|
|
conf/{all,interface}/shared_media is set to TRUE,
|
|
|
|
it will be disabled otherwise
|
|
|
|
default TRUE
|
|
|
|
|
|
|
|
secure_redirects - BOOLEAN
|
|
|
|
Accept ICMP redirect messages only for gateways,
|
|
|
|
listed in default gateway list.
|
|
|
|
secure_redirects for the interface will be enabled if at least one of
|
|
|
|
conf/{all,interface}/secure_redirects is set to TRUE,
|
|
|
|
it will be disabled otherwise
|
|
|
|
default TRUE
|
|
|
|
|
|
|
|
send_redirects - BOOLEAN
|
|
|
|
Send redirects, if router.
|
|
|
|
send_redirects for the interface will be enabled if at least one of
|
|
|
|
conf/{all,interface}/send_redirects is set to TRUE,
|
|
|
|
it will be disabled otherwise
|
|
|
|
Default: TRUE
|
|
|
|
|
|
|
|
bootp_relay - BOOLEAN
|
|
|
|
Accept packets with source address 0.b.c.d destined
|
|
|
|
not to this host as local ones. It is supposed, that
|
|
|
|
BOOTP relay daemon will catch and forward such packets.
|
|
|
|
conf/all/bootp_relay must also be set to TRUE to enable BOOTP relay
|
|
|
|
for the interface
|
|
|
|
default FALSE
|
|
|
|
Not Implemented Yet.
|
|
|
|
|
|
|
|
accept_source_route - BOOLEAN
|
|
|
|
Accept packets with SRR option.
|
|
|
|
conf/all/accept_source_route must also be set to TRUE to accept packets
|
|
|
|
with SRR option on the interface
|
|
|
|
default TRUE (router)
|
|
|
|
FALSE (host)
|
|
|
|
|
2009-12-03 09:25:58 +08:00
|
|
|
accept_local - BOOLEAN
|
2012-07-01 13:39:27 +08:00
|
|
|
Accept packets with local source addresses. In combination
|
|
|
|
with suitable routing, this can be used to direct packets
|
|
|
|
between two local interfaces over the wire and have them
|
|
|
|
accepted properly.
|
|
|
|
|
|
|
|
rp_filter must be set to a non-zero value in order for
|
|
|
|
accept_local to have an effect.
|
|
|
|
|
2009-12-03 09:25:58 +08:00
|
|
|
default FALSE
|
|
|
|
|
2012-06-12 08:44:01 +08:00
|
|
|
route_localnet - BOOLEAN
|
|
|
|
Do not consider loopback addresses as martian source or destination
|
|
|
|
while routing. This enables the use of 127/8 for local routing purposes.
|
|
|
|
default FALSE
|
|
|
|
|
2009-02-20 16:25:36 +08:00
|
|
|
rp_filter - INTEGER
|
2005-04-17 06:20:36 +08:00
|
|
|
0 - No source validation.
|
2009-02-20 16:25:36 +08:00
|
|
|
1 - Strict mode as defined in RFC3704 Strict Reverse Path
|
|
|
|
Each incoming packet is tested against the FIB and if the interface
|
|
|
|
is not the best reverse path the packet check will fail.
|
|
|
|
By default failed packets are discarded.
|
|
|
|
2 - Loose mode as defined in RFC3704 Loose Reverse Path
|
|
|
|
Each incoming packet's source address is also tested against the FIB
|
|
|
|
and if the source address is not reachable via any interface
|
|
|
|
the packet check will fail.
|
|
|
|
|
2009-02-23 12:39:04 +08:00
|
|
|
Current recommended practice in RFC3704 is to enable strict mode
|
2009-02-23 12:37:55 +08:00
|
|
|
to prevent IP spoofing from DDos attacks. If using asymmetric routing
|
2009-02-23 12:39:04 +08:00
|
|
|
or other complicated routing, then loose mode is recommended.
|
2009-02-20 16:25:36 +08:00
|
|
|
|
2009-12-03 07:39:04 +08:00
|
|
|
The max value from conf/{all,interface}/rp_filter is used
|
|
|
|
when doing source validation on the {interface}.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
Default value is 0. Note that some distributions enable it
|
|
|
|
in startup scripts.
|
|
|
|
|
|
|
|
arp_filter - BOOLEAN
|
|
|
|
1 - Allows you to have multiple network interfaces on the same
|
|
|
|
subnet, and have the ARPs for each interface be answered
|
|
|
|
based on whether or not the kernel would route a packet from
|
|
|
|
the ARP'd IP out that interface (therefore you must use source
|
|
|
|
based routing for this to work). In other words it allows control
|
|
|
|
of which cards (usually 1) will respond to an arp request.
|
|
|
|
|
|
|
|
0 - (default) The kernel can respond to arp requests with addresses
|
|
|
|
from other interfaces. This may seem wrong but it usually makes
|
|
|
|
sense, because it increases the chance of successful communication.
|
|
|
|
IP addresses are owned by the complete host on Linux, not by
|
|
|
|
particular interfaces. Only for more complex setups like load-
|
|
|
|
balancing, does this behaviour cause problems.
|
|
|
|
|
|
|
|
arp_filter for the interface will be enabled if at least one of
|
|
|
|
conf/{all,interface}/arp_filter is set to TRUE,
|
|
|
|
it will be disabled otherwise
|
|
|
|
|
|
|
|
arp_announce - INTEGER
|
|
|
|
Define different restriction levels for announcing the local
|
|
|
|
source IP address from IP packets in ARP requests sent on
|
|
|
|
interface:
|
|
|
|
0 - (default) Use any local address, configured on any interface
|
|
|
|
1 - Try to avoid local addresses that are not in the target's
|
|
|
|
subnet for this interface. This mode is useful when target
|
|
|
|
hosts reachable via this interface require the source IP
|
|
|
|
address in ARP requests to be part of their logical network
|
|
|
|
configured on the receiving interface. When we generate the
|
|
|
|
request we will check all our subnets that include the
|
|
|
|
target IP and will preserve the source address if it is from
|
|
|
|
such subnet. If there is no such subnet we select source
|
|
|
|
address according to the rules for level 2.
|
|
|
|
2 - Always use the best local address for this target.
|
|
|
|
In this mode we ignore the source address in the IP packet
|
|
|
|
and try to select local address that we prefer for talks with
|
|
|
|
the target host. Such local address is selected by looking
|
|
|
|
for primary IP addresses on all our subnets on the outgoing
|
|
|
|
interface that include the target IP address. If no suitable
|
|
|
|
local address is found we select the first local address
|
|
|
|
we have on the outgoing interface or on all other interfaces,
|
|
|
|
with the hope we will receive reply for our request and
|
|
|
|
even sometimes no matter the source IP address we announce.
|
|
|
|
|
|
|
|
The max value from conf/{all,interface}/arp_announce is used.
|
|
|
|
|
|
|
|
Increasing the restriction level gives more chance for
|
|
|
|
receiving answer from the resolved target while decreasing
|
|
|
|
the level announces more valid sender's information.
|
|
|
|
|
|
|
|
arp_ignore - INTEGER
|
|
|
|
Define different modes for sending replies in response to
|
|
|
|
received ARP requests that resolve local target IP addresses:
|
|
|
|
0 - (default): reply for any local target IP address, configured
|
|
|
|
on any interface
|
|
|
|
1 - reply only if the target IP address is local address
|
|
|
|
configured on the incoming interface
|
|
|
|
2 - reply only if the target IP address is local address
|
|
|
|
configured on the incoming interface and both with the
|
|
|
|
sender's IP address are part from same subnet on this interface
|
|
|
|
3 - do not reply for local addresses configured with scope host,
|
|
|
|
only resolutions for global and link addresses are replied
|
|
|
|
4-7 - reserved
|
|
|
|
8 - do not reply for all local addresses
|
|
|
|
|
|
|
|
The max value from conf/{all,interface}/arp_ignore is used
|
|
|
|
when ARP request is received on the {interface}
|
|
|
|
|
2009-02-01 17:04:33 +08:00
|
|
|
arp_notify - BOOLEAN
|
|
|
|
Define mode for notification of address and device changes.
|
|
|
|
0 - (default): do nothing
|
2010-05-26 08:09:41 +08:00
|
|
|
1 - Generate gratuitous arp requests when device is brought up
|
2009-02-01 17:04:33 +08:00
|
|
|
or hardware address changes.
|
|
|
|
|
2006-03-21 14:40:03 +08:00
|
|
|
arp_accept - BOOLEAN
|
2010-01-18 20:58:44 +08:00
|
|
|
Define behavior for gratuitous ARP frames who's IP is not
|
|
|
|
already present in the ARP table:
|
|
|
|
0 - don't create new entries in the ARP table
|
|
|
|
1 - create new entries in the ARP table
|
|
|
|
|
|
|
|
Both replies and requests type gratuitous arp will trigger the
|
|
|
|
ARP table to be updated, if this setting is on.
|
|
|
|
|
|
|
|
If the ARP table already contains the IP address of the
|
|
|
|
gratuitous arp frame, the arp table will be updated regardless
|
|
|
|
if this setting is on or off.
|
|
|
|
|
2006-03-21 14:40:03 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
app_solicit - INTEGER
|
|
|
|
The maximum number of probes to send to the user space ARP daemon
|
|
|
|
via netlink before dropping back to multicast probes (see
|
|
|
|
mcast_solicit). Defaults to 0.
|
|
|
|
|
|
|
|
disable_policy - BOOLEAN
|
|
|
|
Disable IPSEC policy (SPD) for this interface
|
|
|
|
|
|
|
|
disable_xfrm - BOOLEAN
|
|
|
|
Disable IPSEC encryption on this interface, whatever the policy
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
tag - INTEGER
|
|
|
|
Allows you to write a number, which can be used as required.
|
|
|
|
Default value is 0.
|
|
|
|
|
|
|
|
Alexey Kuznetsov.
|
|
|
|
kuznet@ms2.inr.ac.ru
|
|
|
|
|
|
|
|
Updated by:
|
|
|
|
Andi Kleen
|
|
|
|
ak@muc.de
|
|
|
|
Nicolas Delon
|
|
|
|
delon.nicolas@wanadoo.fr
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/proc/sys/net/ipv6/* Variables:
|
|
|
|
|
|
|
|
IPv6 has no global variables such as tcp_*. tcp_* settings under ipv4/ also
|
|
|
|
apply to IPv6 [XXX?].
|
|
|
|
|
|
|
|
bindv6only - BOOLEAN
|
|
|
|
Default value for IPV6_V6ONLY socket option,
|
2009-02-23 12:39:04 +08:00
|
|
|
which restricts use of the IPv6 socket to IPv6 communication
|
2005-04-17 06:20:36 +08:00
|
|
|
only.
|
|
|
|
TRUE: disable IPv4-mapped address feature
|
|
|
|
FALSE: enable IPv4-mapped address feature
|
|
|
|
|
2011-08-23 02:28:57 +08:00
|
|
|
Default: FALSE (as specified in RFC3493)
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
IPv6 Fragmentation:
|
|
|
|
|
|
|
|
ip6frag_high_thresh - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
Maximum memory used to reassemble IPv6 fragments. When
|
2005-04-17 06:20:36 +08:00
|
|
|
ip6frag_high_thresh bytes of memory is allocated for this purpose,
|
|
|
|
the fragment handler will toss packets until ip6frag_low_thresh
|
|
|
|
is reached.
|
2009-02-23 12:39:04 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
ip6frag_low_thresh - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
See ip6frag_high_thresh
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
ip6frag_time - INTEGER
|
|
|
|
Time in seconds to keep an IPv6 fragment in memory.
|
|
|
|
|
|
|
|
ip6frag_secret_interval - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
Regeneration interval (in seconds) of the hash secret (or lifetime
|
2005-04-17 06:20:36 +08:00
|
|
|
for the hash secret) for IPv6 fragments.
|
|
|
|
Default: 600
|
|
|
|
|
|
|
|
conf/default/*:
|
|
|
|
Change the interface-specific default settings.
|
|
|
|
|
|
|
|
|
|
|
|
conf/all/*:
|
2009-02-23 12:39:04 +08:00
|
|
|
Change all the interface-specific settings.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
[XXX: Other special features than forwarding?]
|
|
|
|
|
|
|
|
conf/all/forwarding - BOOLEAN
|
2009-02-23 12:39:04 +08:00
|
|
|
Enable global IPv6 forwarding between all interfaces.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2009-02-23 12:39:04 +08:00
|
|
|
IPv4 and IPv6 work differently here; e.g. netfilter must be used
|
2005-04-17 06:20:36 +08:00
|
|
|
to control which interfaces may forward packets and which not.
|
|
|
|
|
2009-02-23 12:39:04 +08:00
|
|
|
This also sets all interfaces' Host/Router setting
|
2005-04-17 06:20:36 +08:00
|
|
|
'forwarding' to the specified value. See below for details.
|
|
|
|
|
|
|
|
This referred to as global forwarding.
|
|
|
|
|
2006-09-23 05:43:49 +08:00
|
|
|
proxy_ndp - BOOLEAN
|
|
|
|
Do proxy ndp.
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
conf/interface/*:
|
|
|
|
Change special settings per interface.
|
|
|
|
|
2009-02-23 12:39:04 +08:00
|
|
|
The functional behaviour for certain settings is different
|
2005-04-17 06:20:36 +08:00
|
|
|
depending on whether local forwarding is enabled or not.
|
|
|
|
|
2011-09-29 03:51:54 +08:00
|
|
|
accept_ra - INTEGER
|
2005-04-17 06:20:36 +08:00
|
|
|
Accept Router Advertisements; autoconfigure using them.
|
2009-02-23 12:39:04 +08:00
|
|
|
|
ipv6: Send ICMPv6 RSes only when RAs are accepted
This patch improves the logic determining when to send ICMPv6 Router
Solicitations, so that they are 1) always sent when the kernel is
accepting Router Advertisements, and 2) never sent when the kernel is
not accepting RAs. In other words, the operational setting of the
"accept_ra" sysctl is used.
The change also makes the special "Hybrid Router" forwarding mode
("forwarding" sysctl set to 2) operate exactly the same as the standard
Router mode (forwarding=1). The only difference between the two was
that RSes was being sent in the Hybrid Router mode only. The sysctl
documentation describing the special Hybrid Router mode has therefore
been removed.
Rationale for the change:
Currently, the value of forwarding sysctl is the only thing determining
whether or not to send RSes. If it has the value 0 or 2, they are sent,
otherwise they are not. This leads to inconsistent behaviour in the
following cases:
* accept_ra=0, forwarding=0
* accept_ra=0, forwarding=2
* accept_ra=1, forwarding=2
* accept_ra=2, forwarding=1
In the first three cases, the kernel will send RSes, even though it will
not accept any RAs received in reply. In the last case, it will not send
any RSes, even though it will accept and process any RAs received. (Most
routers will send unsolicited RAs periodically, so suppressing RSes in
the last case will merely delay auto-configuration, not prevent it.)
Also, it is my opinion that having the forwarding sysctl control RS
sending behaviour (completely independent of whether RAs are being
accepted or not) is simply not what most users would intuitively expect
to be the case.
Signed-off-by: Tore Anderson <tore@fud.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-08-29 07:47:33 +08:00
|
|
|
It also determines whether or not to transmit Router
|
|
|
|
Solicitations. If and only if the functional setting is to
|
|
|
|
accept Router Advertisements, Router Solicitations will be
|
|
|
|
transmitted.
|
|
|
|
|
2010-09-03 13:47:30 +08:00
|
|
|
Possible values are:
|
|
|
|
0 Do not accept Router Advertisements.
|
|
|
|
1 Accept Router Advertisements if forwarding is disabled.
|
|
|
|
2 Overrule forwarding behaviour. Accept Router Advertisements
|
|
|
|
even if forwarding is enabled.
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
Functional default: enabled if local forwarding is disabled.
|
|
|
|
disabled if local forwarding is enabled.
|
|
|
|
|
2006-03-21 08:55:08 +08:00
|
|
|
accept_ra_defrtr - BOOLEAN
|
|
|
|
Learn default router in Router Advertisement.
|
|
|
|
|
|
|
|
Functional default: enabled if accept_ra is enabled.
|
|
|
|
disabled if accept_ra is disabled.
|
|
|
|
|
2006-03-21 08:55:26 +08:00
|
|
|
accept_ra_pinfo - BOOLEAN
|
2006-10-04 04:50:39 +08:00
|
|
|
Learn Prefix Information in Router Advertisement.
|
2006-03-21 08:55:26 +08:00
|
|
|
|
|
|
|
Functional default: enabled if accept_ra is enabled.
|
|
|
|
disabled if accept_ra is disabled.
|
|
|
|
|
2006-03-21 09:07:03 +08:00
|
|
|
accept_ra_rt_info_max_plen - INTEGER
|
|
|
|
Maximum prefix length of Route Information in RA.
|
|
|
|
|
|
|
|
Route Information w/ prefix larger than or equal to this
|
|
|
|
variable shall be ignored.
|
|
|
|
|
|
|
|
Functional default: 0 if accept_ra_rtr_pref is enabled.
|
|
|
|
-1 if accept_ra_rtr_pref is disabled.
|
|
|
|
|
2006-03-21 09:05:30 +08:00
|
|
|
accept_ra_rtr_pref - BOOLEAN
|
|
|
|
Accept Router Preference in RA.
|
|
|
|
|
|
|
|
Functional default: enabled if accept_ra is enabled.
|
|
|
|
disabled if accept_ra is disabled.
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
accept_redirects - BOOLEAN
|
|
|
|
Accept Redirects.
|
|
|
|
|
|
|
|
Functional default: enabled if local forwarding is disabled.
|
|
|
|
disabled if local forwarding is enabled.
|
|
|
|
|
2007-04-25 05:58:30 +08:00
|
|
|
accept_source_route - INTEGER
|
|
|
|
Accept source routing (routing extension header).
|
|
|
|
|
2007-07-11 13:55:49 +08:00
|
|
|
>= 0: Accept only routing header type 2.
|
2007-04-25 05:58:30 +08:00
|
|
|
< 0: Do not accept routing header.
|
|
|
|
|
|
|
|
Default: 0
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
autoconf - BOOLEAN
|
2009-02-23 12:39:04 +08:00
|
|
|
Autoconfigure addresses using Prefix Information in Router
|
2005-04-17 06:20:36 +08:00
|
|
|
Advertisements.
|
|
|
|
|
2006-03-21 08:55:26 +08:00
|
|
|
Functional default: enabled if accept_ra_pinfo is enabled.
|
|
|
|
disabled if accept_ra_pinfo is disabled.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
dad_transmits - INTEGER
|
|
|
|
The amount of Duplicate Address Detection probes to send.
|
|
|
|
Default: 1
|
2009-02-23 12:39:04 +08:00
|
|
|
|
2011-09-29 03:51:54 +08:00
|
|
|
forwarding - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
Configure interface-specific Host/Router behaviour.
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2009-02-23 12:39:04 +08:00
|
|
|
Note: It is recommended to have the same setting on all
|
2005-04-17 06:20:36 +08:00
|
|
|
interfaces; mixed router/host scenarios are rather uncommon.
|
|
|
|
|
2010-09-03 13:47:30 +08:00
|
|
|
Possible values are:
|
|
|
|
0 Forwarding disabled
|
|
|
|
1 Forwarding enabled
|
|
|
|
|
|
|
|
FALSE (0):
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
By default, Host behaviour is assumed. This means:
|
|
|
|
|
|
|
|
1. IsRouter flag is not set in Neighbour Advertisements.
|
ipv6: Send ICMPv6 RSes only when RAs are accepted
This patch improves the logic determining when to send ICMPv6 Router
Solicitations, so that they are 1) always sent when the kernel is
accepting Router Advertisements, and 2) never sent when the kernel is
not accepting RAs. In other words, the operational setting of the
"accept_ra" sysctl is used.
The change also makes the special "Hybrid Router" forwarding mode
("forwarding" sysctl set to 2) operate exactly the same as the standard
Router mode (forwarding=1). The only difference between the two was
that RSes was being sent in the Hybrid Router mode only. The sysctl
documentation describing the special Hybrid Router mode has therefore
been removed.
Rationale for the change:
Currently, the value of forwarding sysctl is the only thing determining
whether or not to send RSes. If it has the value 0 or 2, they are sent,
otherwise they are not. This leads to inconsistent behaviour in the
following cases:
* accept_ra=0, forwarding=0
* accept_ra=0, forwarding=2
* accept_ra=1, forwarding=2
* accept_ra=2, forwarding=1
In the first three cases, the kernel will send RSes, even though it will
not accept any RAs received in reply. In the last case, it will not send
any RSes, even though it will accept and process any RAs received. (Most
routers will send unsolicited RAs periodically, so suppressing RSes in
the last case will merely delay auto-configuration, not prevent it.)
Also, it is my opinion that having the forwarding sysctl control RS
sending behaviour (completely independent of whether RAs are being
accepted or not) is simply not what most users would intuitively expect
to be the case.
Signed-off-by: Tore Anderson <tore@fud.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-08-29 07:47:33 +08:00
|
|
|
2. If accept_ra is TRUE (default), transmit Router
|
|
|
|
Solicitations.
|
2009-02-23 12:39:04 +08:00
|
|
|
3. If accept_ra is TRUE (default), accept Router
|
2005-04-17 06:20:36 +08:00
|
|
|
Advertisements (and do autoconfiguration).
|
|
|
|
4. If accept_redirects is TRUE (default), accept Redirects.
|
|
|
|
|
2010-09-03 13:47:30 +08:00
|
|
|
TRUE (1):
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2009-02-23 12:39:04 +08:00
|
|
|
If local forwarding is enabled, Router behaviour is assumed.
|
2005-04-17 06:20:36 +08:00
|
|
|
This means exactly the reverse from the above:
|
|
|
|
|
|
|
|
1. IsRouter flag is set in Neighbour Advertisements.
|
ipv6: Send ICMPv6 RSes only when RAs are accepted
This patch improves the logic determining when to send ICMPv6 Router
Solicitations, so that they are 1) always sent when the kernel is
accepting Router Advertisements, and 2) never sent when the kernel is
not accepting RAs. In other words, the operational setting of the
"accept_ra" sysctl is used.
The change also makes the special "Hybrid Router" forwarding mode
("forwarding" sysctl set to 2) operate exactly the same as the standard
Router mode (forwarding=1). The only difference between the two was
that RSes was being sent in the Hybrid Router mode only. The sysctl
documentation describing the special Hybrid Router mode has therefore
been removed.
Rationale for the change:
Currently, the value of forwarding sysctl is the only thing determining
whether or not to send RSes. If it has the value 0 or 2, they are sent,
otherwise they are not. This leads to inconsistent behaviour in the
following cases:
* accept_ra=0, forwarding=0
* accept_ra=0, forwarding=2
* accept_ra=1, forwarding=2
* accept_ra=2, forwarding=1
In the first three cases, the kernel will send RSes, even though it will
not accept any RAs received in reply. In the last case, it will not send
any RSes, even though it will accept and process any RAs received. (Most
routers will send unsolicited RAs periodically, so suppressing RSes in
the last case will merely delay auto-configuration, not prevent it.)
Also, it is my opinion that having the forwarding sysctl control RS
sending behaviour (completely independent of whether RAs are being
accepted or not) is simply not what most users would intuitively expect
to be the case.
Signed-off-by: Tore Anderson <tore@fud.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-08-29 07:47:33 +08:00
|
|
|
2. Router Solicitations are not sent unless accept_ra is 2.
|
2010-09-03 13:47:30 +08:00
|
|
|
3. Router Advertisements are ignored unless accept_ra is 2.
|
2005-04-17 06:20:36 +08:00
|
|
|
4. Redirects are ignored.
|
|
|
|
|
2010-09-03 13:47:30 +08:00
|
|
|
Default: 0 (disabled) if global forwarding is disabled (default),
|
|
|
|
otherwise 1 (enabled).
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
hop_limit - INTEGER
|
|
|
|
Default Hop Limit to set.
|
|
|
|
Default: 64
|
|
|
|
|
|
|
|
mtu - INTEGER
|
|
|
|
Default Maximum Transfer Unit
|
|
|
|
Default: 1280 (IPv6 required minimum)
|
|
|
|
|
2006-03-21 09:05:47 +08:00
|
|
|
router_probe_interval - INTEGER
|
|
|
|
Minimum interval (in seconds) between Router Probing described
|
|
|
|
in RFC4191.
|
|
|
|
|
|
|
|
Default: 60
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
router_solicitation_delay - INTEGER
|
|
|
|
Number of seconds to wait after interface is brought up
|
|
|
|
before sending Router Solicitations.
|
|
|
|
Default: 1
|
|
|
|
|
|
|
|
router_solicitation_interval - INTEGER
|
|
|
|
Number of seconds to wait between Router Solicitations.
|
|
|
|
Default: 4
|
|
|
|
|
|
|
|
router_solicitations - INTEGER
|
2009-02-23 12:39:04 +08:00
|
|
|
Number of Router Solicitations to send until assuming no
|
2005-04-17 06:20:36 +08:00
|
|
|
routers are present.
|
|
|
|
Default: 3
|
|
|
|
|
|
|
|
use_tempaddr - INTEGER
|
|
|
|
Preference for Privacy Extensions (RFC3041).
|
|
|
|
<= 0 : disable Privacy Extensions
|
|
|
|
== 1 : enable Privacy Extensions, but prefer public
|
|
|
|
addresses over temporary addresses.
|
|
|
|
> 1 : enable Privacy Extensions and prefer temporary
|
|
|
|
addresses over public addresses.
|
|
|
|
Default: 0 (for most devices)
|
|
|
|
-1 (for point-to-point devices and loopback devices)
|
|
|
|
|
|
|
|
temp_valid_lft - INTEGER
|
|
|
|
valid lifetime (in seconds) for temporary addresses.
|
|
|
|
Default: 604800 (7 days)
|
|
|
|
|
|
|
|
temp_prefered_lft - INTEGER
|
|
|
|
Preferred lifetime (in seconds) for temporary addresses.
|
|
|
|
Default: 86400 (1 day)
|
|
|
|
|
|
|
|
max_desync_factor - INTEGER
|
|
|
|
Maximum value for DESYNC_FACTOR, which is a random value
|
2009-02-23 12:39:04 +08:00
|
|
|
that ensures that clients don't synchronize with each
|
2005-04-17 06:20:36 +08:00
|
|
|
other and generate new addresses at exactly the same time.
|
|
|
|
value is in seconds.
|
|
|
|
Default: 600
|
2009-02-23 12:39:04 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
regen_max_retry - INTEGER
|
|
|
|
Number of attempts before give up attempting to generate
|
|
|
|
valid temporary addresses.
|
|
|
|
Default: 5
|
|
|
|
|
|
|
|
max_addresses - INTEGER
|
2010-02-22 20:27:21 +08:00
|
|
|
Maximum number of autoconfigured addresses per interface. Setting
|
|
|
|
to zero disables the limitation. It is not recommended to set this
|
|
|
|
value too large (or to zero) because it would be an easy way to
|
|
|
|
crash the kernel by allowing too many addresses to be created.
|
2005-04-17 06:20:36 +08:00
|
|
|
Default: 16
|
|
|
|
|
2008-06-28 13:17:11 +08:00
|
|
|
disable_ipv6 - BOOLEAN
|
2009-03-19 09:22:48 +08:00
|
|
|
Disable IPv6 operation. If accept_dad is set to 2, this value
|
|
|
|
will be dynamically set to TRUE if DAD fails for the link-local
|
|
|
|
address.
|
2008-06-28 13:17:11 +08:00
|
|
|
Default: FALSE (enable IPv6 operation)
|
|
|
|
|
2009-06-01 18:07:33 +08:00
|
|
|
When this value is changed from 1 to 0 (IPv6 is being enabled),
|
|
|
|
it will dynamically create a link-local address on the given
|
|
|
|
interface and start Duplicate Address Detection, if necessary.
|
|
|
|
|
|
|
|
When this value is changed from 0 to 1 (IPv6 is being disabled),
|
|
|
|
it will dynamically delete all address on the given interface.
|
|
|
|
|
2008-06-28 13:18:38 +08:00
|
|
|
accept_dad - INTEGER
|
|
|
|
Whether to accept DAD (Duplicate Address Detection).
|
|
|
|
0: Disable DAD
|
|
|
|
1: Enable DAD (default)
|
|
|
|
2: Enable DAD, and disable IPv6 operation if MAC-based duplicate
|
|
|
|
link-local address has been found.
|
|
|
|
|
2009-10-02 19:39:15 +08:00
|
|
|
force_tllao - BOOLEAN
|
|
|
|
Enable sending the target link-layer address option even when
|
|
|
|
responding to a unicast neighbor solicitation.
|
|
|
|
Default: FALSE
|
|
|
|
|
|
|
|
Quoting from RFC 2461, section 4.4, Target link-layer address:
|
|
|
|
|
|
|
|
"The option MUST be included for multicast solicitations in order to
|
|
|
|
avoid infinite Neighbor Solicitation "recursion" when the peer node
|
|
|
|
does not have a cache entry to return a Neighbor Advertisements
|
|
|
|
message. When responding to unicast solicitations, the option can be
|
|
|
|
omitted since the sender of the solicitation has the correct link-
|
|
|
|
layer address; otherwise it would not have be able to send the unicast
|
|
|
|
solicitation in the first place. However, including the link-layer
|
|
|
|
address in this case adds little overhead and eliminates a potential
|
|
|
|
race condition where the sender deletes the cached link-layer address
|
|
|
|
prior to receiving a response to a previous solicitation."
|
|
|
|
|
2013-01-01 08:35:31 +08:00
|
|
|
ndisc_notify - BOOLEAN
|
|
|
|
Define mode for notification of address and device changes.
|
|
|
|
0 - (default): do nothing
|
|
|
|
1 - Generate unsolicited neighbour advertisements when device is brought
|
|
|
|
up or hardware address changes.
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
icmp/*:
|
|
|
|
ratelimit - INTEGER
|
|
|
|
Limit the maximal rates for sending ICMPv6 packets.
|
2008-07-02 10:29:07 +08:00
|
|
|
0 to disable any limiting,
|
|
|
|
otherwise the minimal space between responses in milliseconds.
|
|
|
|
Default: 1000
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
|
|
|
|
IPv6 Update by:
|
|
|
|
Pekka Savola <pekkas@netcore.fi>
|
|
|
|
YOSHIFUJI Hideaki / USAGI Project <yoshfuji@linux-ipv6.org>
|
|
|
|
|
|
|
|
|
|
|
|
/proc/sys/net/bridge/* Variables:
|
|
|
|
|
|
|
|
bridge-nf-call-arptables - BOOLEAN
|
|
|
|
1 : pass bridged ARP traffic to arptables' FORWARD chain.
|
|
|
|
0 : disable this.
|
|
|
|
Default: 1
|
|
|
|
|
|
|
|
bridge-nf-call-iptables - BOOLEAN
|
|
|
|
1 : pass bridged IPv4 traffic to iptables' chains.
|
|
|
|
0 : disable this.
|
|
|
|
Default: 1
|
|
|
|
|
|
|
|
bridge-nf-call-ip6tables - BOOLEAN
|
|
|
|
1 : pass bridged IPv6 traffic to ip6tables' chains.
|
|
|
|
0 : disable this.
|
|
|
|
Default: 1
|
|
|
|
|
|
|
|
bridge-nf-filter-vlan-tagged - BOOLEAN
|
2007-04-13 13:14:23 +08:00
|
|
|
1 : pass bridged vlan-tagged ARP/IP/IPv6 traffic to {arp,ip,ip6}tables.
|
|
|
|
0 : disable this.
|
2012-05-09 01:36:44 +08:00
|
|
|
Default: 0
|
2007-04-13 13:14:23 +08:00
|
|
|
|
|
|
|
bridge-nf-filter-pppoe-tagged - BOOLEAN
|
|
|
|
1 : pass bridged pppoe-tagged IP/IPv6 traffic to {ip,ip6}tables.
|
2005-04-17 06:20:36 +08:00
|
|
|
0 : disable this.
|
2012-05-09 01:36:44 +08:00
|
|
|
Default: 0
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2012-05-09 01:36:44 +08:00
|
|
|
bridge-nf-pass-vlan-input-dev - BOOLEAN
|
|
|
|
1: if bridge-nf-filter-vlan-tagged is enabled, try to find a vlan
|
|
|
|
interface on the bridge and set the netfilter input device to the vlan.
|
|
|
|
This allows use of e.g. "iptables -i br0.1" and makes the REDIRECT
|
|
|
|
target work with vlan-on-top-of-bridge interfaces. When no matching
|
|
|
|
vlan interface is found, or this switch is off, the input device is
|
|
|
|
set to the bridge interface.
|
|
|
|
0: disable bridge netfilter vlan interface lookup.
|
|
|
|
Default: 0
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-07-09 07:43:29 +08:00
|
|
|
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
|
|
|
|
|
2012-07-21 15:56:07 +08:00
|
|
|
pf_retrans - INTEGER
|
|
|
|
The number of retransmissions that will be attempted on a given path
|
|
|
|
before traffic is redirected to an alternate transport (should one
|
|
|
|
exist). Note this is distinct from path_max_retrans, as a path that
|
|
|
|
passes the pf_retrans threshold can still be used. Its only
|
|
|
|
deprioritized when a transmission path is selected by the stack. This
|
|
|
|
setting is primarily used to enable fast failover mechanisms without
|
|
|
|
having to reduce path_max_retrans to a very low value. See:
|
|
|
|
http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt
|
|
|
|
for details. Note also that a value of pf_retrans > path_max_retrans
|
|
|
|
disables this feature
|
|
|
|
|
|
|
|
Default: 0
|
|
|
|
|
2008-07-09 07:43:29 +08:00
|
|
|
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
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-07-09 07:43:29 +08:00
|
|
|
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
|
|
|
|
|
2012-10-24 17:20:03 +08:00
|
|
|
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
|
2013-01-03 15:50:29 +08:00
|
|
|
configuration of those algorithms at build time (CONFIG_CRYPTO_MD5 and
|
2012-10-24 17:20:03 +08:00
|
|
|
CONFIG_CRYPTO_SHA1).
|
|
|
|
|
|
|
|
Default: Dependent on configuration. MD5 if available, else SHA1 if
|
|
|
|
available, else none.
|
|
|
|
|
2008-07-09 07:43:29 +08:00
|
|
|
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
|
2013-01-03 15:50:29 +08:00
|
|
|
0: rcvbuf space is per socket
|
2008-07-09 07:43:29 +08:00
|
|
|
|
|
|
|
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
|
2011-06-20 06:08:10 +08:00
|
|
|
Only the first value ("min") is used, "default" and "max" are
|
|
|
|
ignored.
|
|
|
|
|
|
|
|
min: Minimal size of receive buffer used by SCTP socket.
|
|
|
|
It is guaranteed to each SCTP socket (but not association) even
|
|
|
|
under moderate memory pressure.
|
|
|
|
|
|
|
|
Default: 1 page
|
2008-07-09 07:43:29 +08:00
|
|
|
|
|
|
|
sctp_wmem - vector of 3 INTEGERs: min, default, max
|
2011-06-20 06:08:10 +08:00
|
|
|
Currently this tunable has no effect.
|
2008-07-09 07:43:29 +08:00
|
|
|
|
2009-09-03 19:55:47 +08:00
|
|
|
addr_scope_policy - INTEGER
|
|
|
|
Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00
|
|
|
|
|
|
|
|
0 - Disable IPv4 address scoping
|
|
|
|
1 - Enable IPv4 address scoping
|
|
|
|
2 - Follow draft but allow IPv4 private addresses
|
|
|
|
3 - Follow draft but allow IPv4 link local addresses
|
|
|
|
|
|
|
|
Default: 1
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-07-11 07:50:26 +08:00
|
|
|
/proc/sys/net/core/*
|
2012-04-27 00:52:52 +08:00
|
|
|
Please see: Documentation/sysctl/net.txt for descriptions of these entries.
|
2009-05-15 06:49:36 +08:00
|
|
|
|
2008-07-11 07:50:26 +08:00
|
|
|
|
|
|
|
/proc/sys/net/unix/*
|
2009-05-15 06:49:36 +08:00
|
|
|
max_dgram_qlen - INTEGER
|
|
|
|
The maximum length of dgram socket receive queue
|
|
|
|
|
|
|
|
Default: 10
|
|
|
|
|
|
|
|
|
|
|
|
UNDOCUMENTED:
|
2008-07-11 07:50:26 +08:00
|
|
|
|
|
|
|
/proc/sys/net/irda/*
|
|
|
|
fast_poll_increase FIXME
|
|
|
|
warn_noreply_time FIXME
|
|
|
|
discovery_slots FIXME
|
|
|
|
slot_timeout FIXME
|
|
|
|
max_baud_rate FIXME
|
|
|
|
discovery_timeout FIXME
|
|
|
|
lap_keepalive_time FIXME
|
|
|
|
max_noreply_time FIXME
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max_tx_data_size FIXME
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max_tx_window FIXME
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min_tx_turn_time FIXME
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