From e8648a1fdb54da1f683784b36a17aa65ea56e931 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 23 Jul 2010 12:59:36 +0200 Subject: [PATCH] netfilter: add xt_cpu match In some situations a CPU match permits a better spreading of connections, or select targets only for a given cpu. With Remote Packet Steering or multiqueue NIC and appropriate IRQ affinities, we can distribute trafic on available cpus, per session. (all RX packets for a given flow is handled by a given cpu) Some legacy applications being not SMP friendly, one way to scale a server is to run multiple copies of them. Instead of randomly choosing an instance, we can use the cpu number as a key so that softirq handler for a whole instance is running on a single cpu, maximizing cache effects in TCP/UDP stacks. Using NAT for example, a four ways machine might run four copies of server application, using a separate listening port for each instance, but still presenting an unique external port : iptables -t nat -A PREROUTING -p tcp --dport 80 -m cpu --cpu 0 \ -j REDIRECT --to-port 8080 iptables -t nat -A PREROUTING -p tcp --dport 80 -m cpu --cpu 1 \ -j REDIRECT --to-port 8081 iptables -t nat -A PREROUTING -p tcp --dport 80 -m cpu --cpu 2 \ -j REDIRECT --to-port 8082 iptables -t nat -A PREROUTING -p tcp --dport 80 -m cpu --cpu 3 \ -j REDIRECT --to-port 8083 Signed-off-by: Eric Dumazet Signed-off-by: Patrick McHardy --- include/linux/netfilter/Kbuild | 3 +- include/linux/netfilter/xt_cpu.h | 11 ++++++ net/netfilter/Kconfig | 9 +++++ net/netfilter/Makefile | 1 + net/netfilter/xt_cpu.c | 63 ++++++++++++++++++++++++++++++++ 5 files changed, 86 insertions(+), 1 deletion(-) create mode 100644 include/linux/netfilter/xt_cpu.h create mode 100644 net/netfilter/xt_cpu.c diff --git a/include/linux/netfilter/Kbuild b/include/linux/netfilter/Kbuild index 0cb62c857187..edeeabdc1500 100644 --- a/include/linux/netfilter/Kbuild +++ b/include/linux/netfilter/Kbuild @@ -20,12 +20,13 @@ header-y += xt_TCPMSS.h header-y += xt_TCPOPTSTRIP.h header-y += xt_TEE.h header-y += xt_TPROXY.h +header-y += xt_cluster.h header-y += xt_comment.h header-y += xt_connbytes.h header-y += xt_connlimit.h header-y += xt_connmark.h header-y += xt_conntrack.h -header-y += xt_cluster.h +header-y += xt_cpu.h header-y += xt_dccp.h header-y += xt_dscp.h header-y += xt_esp.h diff --git a/include/linux/netfilter/xt_cpu.h b/include/linux/netfilter/xt_cpu.h new file mode 100644 index 000000000000..93c7f11d8f42 --- /dev/null +++ b/include/linux/netfilter/xt_cpu.h @@ -0,0 +1,11 @@ +#ifndef _XT_CPU_H +#define _XT_CPU_H + +#include + +struct xt_cpu_info { + __u32 cpu; + __u32 invert; +}; + +#endif /*_XT_CPU_H*/ diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index 551b58419df9..43288259f4a1 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -663,6 +663,15 @@ config NETFILTER_XT_MATCH_CONNTRACK To compile it as a module, choose M here. If unsure, say N. +config NETFILTER_XT_MATCH_CPU + tristate '"cpu" match support' + depends on NETFILTER_ADVANCED + help + CPU matching allows you to match packets based on the CPU + currently handling the packet. + + To compile it as a module, choose M here. If unsure, say N. + config NETFILTER_XT_MATCH_DCCP tristate '"dccp" protocol match support' depends on NETFILTER_ADVANCED diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 4366c79a6683..441050f31111 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -70,6 +70,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_COMMENT) += xt_comment.o obj-$(CONFIG_NETFILTER_XT_MATCH_CONNBYTES) += xt_connbytes.o obj-$(CONFIG_NETFILTER_XT_MATCH_CONNLIMIT) += xt_connlimit.o obj-$(CONFIG_NETFILTER_XT_MATCH_CONNTRACK) += xt_conntrack.o +obj-$(CONFIG_NETFILTER_XT_MATCH_CPU) += xt_cpu.o obj-$(CONFIG_NETFILTER_XT_MATCH_DCCP) += xt_dccp.o obj-$(CONFIG_NETFILTER_XT_MATCH_DSCP) += xt_dscp.o obj-$(CONFIG_NETFILTER_XT_MATCH_ESP) += xt_esp.o diff --git a/net/netfilter/xt_cpu.c b/net/netfilter/xt_cpu.c new file mode 100644 index 000000000000..b39db8a5cbae --- /dev/null +++ b/net/netfilter/xt_cpu.c @@ -0,0 +1,63 @@ +/* Kernel module to match running CPU */ + +/* + * Might be used to distribute connections on several daemons, if + * RPS (Remote Packet Steering) is enabled or NIC is multiqueue capable, + * each RX queue IRQ affined to one CPU (1:1 mapping) + * + */ + +/* (C) 2010 Eric Dumazet + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Eric Dumazet "); +MODULE_DESCRIPTION("Xtables: CPU match"); + +static int cpu_mt_check(const struct xt_mtchk_param *par) +{ + const struct xt_cpu_info *info = par->matchinfo; + + if (info->invert & ~1) + return -EINVAL; + return 0; +} + +static bool cpu_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_cpu_info *info = par->matchinfo; + + return (info->cpu == smp_processor_id()) ^ info->invert; +} + +static struct xt_match cpu_mt_reg __read_mostly = { + .name = "cpu", + .revision = 0, + .family = NFPROTO_UNSPEC, + .checkentry = cpu_mt_check, + .match = cpu_mt, + .matchsize = sizeof(struct xt_cpu_info), + .me = THIS_MODULE, +}; + +static int __init cpu_mt_init(void) +{ + return xt_register_match(&cpu_mt_reg); +} + +static void __exit cpu_mt_exit(void) +{ + xt_unregister_match(&cpu_mt_reg); +} + +module_init(cpu_mt_init); +module_exit(cpu_mt_exit);