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authorEric Dumazet <edumazet@google.com>2014-09-19 07:38:40 -0700
committerDavid S. Miller <davem@davemloft.net>2014-09-23 12:47:38 -0400
commit4cdf507d54525842dfd9f6313fdafba039084046 (patch)
tree3ea6c335251ee0b0bdb404df727ca307d55a9de9 /Documentation/networking
parente8b56d55a30afe588d905913d011678235dda437 (diff)
icmp: add a global rate limitation
Current ICMP rate limiting uses inetpeer cache, which is an RBL tree protected by a lock, meaning that hosts can be stuck hard if all cpus want to check ICMP limits. When say a DNS or NTP server process is restarted, inetpeer tree grows quick and machine comes to its knees. iptables can not help because the bottleneck happens before ICMP messages are even cooked and sent. This patch adds a new global limitation, using a token bucket filter, controlled by two new sysctl : icmp_msgs_per_sec - INTEGER Limit maximal number of ICMP packets sent per second from this host. Only messages whose type matches icmp_ratemask are controlled by this limit. Default: 1000 icmp_msgs_burst - INTEGER icmp_msgs_per_sec controls number of ICMP packets sent per second, while icmp_msgs_burst controls the burst size of these packets. Default: 50 Note that if we really want to send millions of ICMP messages per second, we might extend idea and infra added in commit 04ca6973f7c1a ("ip: make IP identifiers less predictable") : add a token bucket in the ip_idents hash and no longer rely on inetpeer. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/ip-sysctl.txt13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 1b5581a30d77..c7a81ace35d0 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -769,8 +769,21 @@ icmp_ratelimit - INTEGER
icmp_ratemask (see below) to specific targets.
0 to disable any limiting,
otherwise the minimal space between responses in milliseconds.
+ Note that another sysctl, icmp_msgs_per_sec limits the number
+ of ICMP packets sent on all targets.
Default: 1000
+icmp_msgs_per_sec - INTEGER
+ Limit maximal number of ICMP packets sent per second from this host.
+ Only messages whose type matches icmp_ratemask (see below) are
+ controlled by this limit.
+ Default: 1000
+
+icmp_msgs_burst - INTEGER
+ icmp_msgs_per_sec controls number of ICMP packets sent per second,
+ while icmp_msgs_burst controls the burst size of these packets.
+ Default: 50
+
icmp_ratemask - INTEGER
Mask made of ICMP types for which rates are being limited.
Significant bits: IHGFEDCBA9876543210

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