From 4cdf507d54525842dfd9f6313fdafba039084046 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 19 Sep 2014 07:38:40 -0700 Subject: 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 Signed-off-by: David S. Miller --- net/ipv4/sysctl_net_ipv4.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'net/ipv4/sysctl_net_ipv4.c') diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 1599966f463..8a25509c35b 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -730,6 +730,22 @@ static struct ctl_table ipv4_table[] = { .extra1 = &zero, .extra2 = &one, }, + { + .procname = "icmp_msgs_per_sec", + .data = &sysctl_icmp_msgs_per_sec, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + }, + { + .procname = "icmp_msgs_burst", + .data = &sysctl_icmp_msgs_burst, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + }, { .procname = "udp_mem", .data = &sysctl_udp_mem, -- cgit v1.2.3-70-g09d2