diff options
Diffstat (limited to 'net/netfilter/xt_connlimit.c')
| -rw-r--r-- | net/netfilter/xt_connlimit.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/net/netfilter/xt_connlimit.c b/net/netfilter/xt_connlimit.c new file mode 100644 index 000000000..5d04ef80a --- /dev/null +++ b/net/netfilter/xt_connlimit.c @@ -0,0 +1,137 @@ +/* + * netfilter module to limit the number of parallel tcp + * connections per IP address. + * (c) 2000 Gerd Knorr <kraxel@bytesex.org> + * Nov 2002: Martin Bene <martin.bene@icomedias.com>: + * only ignore TIME_WAIT or gone connections + * (C) CC Computer Consultants GmbH, 2007 + * + * based on ... + * + * Kernel module to match connection tracking information. + * GPL (C) 1999 Rusty Russell (rusty@rustcorp.com.au). + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_connlimit.h> + +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_core.h> +#include <net/netfilter/nf_conntrack_tuple.h> +#include <net/netfilter/nf_conntrack_zones.h> +#include <net/netfilter/nf_conntrack_count.h> + +static bool +connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + struct net *net = xt_net(par); + const struct xt_connlimit_info *info = par->matchinfo; + struct nf_conntrack_tuple tuple; + const struct nf_conntrack_tuple *tuple_ptr = &tuple; + const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt; + enum ip_conntrack_info ctinfo; + const struct nf_conn *ct; + unsigned int connections; + u32 key[5]; + + ct = nf_ct_get(skb, &ctinfo); + if (ct != NULL) { + tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; + zone = nf_ct_zone(ct); + } else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), + xt_family(par), net, &tuple)) { + goto hotdrop; + } + + if (xt_family(par) == NFPROTO_IPV6) { + const struct ipv6hdr *iph = ipv6_hdr(skb); + union nf_inet_addr addr; + unsigned int i; + + memcpy(&addr.ip6, (info->flags & XT_CONNLIMIT_DADDR) ? + &iph->daddr : &iph->saddr, sizeof(addr.ip6)); + + for (i = 0; i < ARRAY_SIZE(addr.ip6); ++i) + addr.ip6[i] &= info->mask.ip6[i]; + memcpy(key, &addr, sizeof(addr.ip6)); + key[4] = zone->id; + } else { + const struct iphdr *iph = ip_hdr(skb); + + key[0] = (info->flags & XT_CONNLIMIT_DADDR) ? + (__force __u32)iph->daddr : (__force __u32)iph->saddr; + key[0] &= (__force __u32)info->mask.ip; + key[1] = zone->id; + } + + connections = nf_conncount_count(net, info->data, key, tuple_ptr, + zone); + if (connections == 0) + /* kmalloc failed, drop it entirely */ + goto hotdrop; + + return (connections > info->limit) ^ !!(info->flags & XT_CONNLIMIT_INVERT); + + hotdrop: + par->hotdrop = true; + return false; +} + +static int connlimit_mt_check(const struct xt_mtchk_param *par) +{ + struct xt_connlimit_info *info = par->matchinfo; + unsigned int keylen; + + keylen = sizeof(u32); + if (par->family == NFPROTO_IPV6) + keylen += sizeof(struct in6_addr); + else + keylen += sizeof(struct in_addr); + + /* init private data */ + info->data = nf_conncount_init(par->net, par->family, keylen); + + return PTR_ERR_OR_ZERO(info->data); +} + +static void connlimit_mt_destroy(const struct xt_mtdtor_param *par) +{ + const struct xt_connlimit_info *info = par->matchinfo; + + nf_conncount_destroy(par->net, par->family, info->data); +} + +static struct xt_match connlimit_mt_reg __read_mostly = { + .name = "connlimit", + .revision = 1, + .family = NFPROTO_UNSPEC, + .checkentry = connlimit_mt_check, + .match = connlimit_mt, + .matchsize = sizeof(struct xt_connlimit_info), + .usersize = offsetof(struct xt_connlimit_info, data), + .destroy = connlimit_mt_destroy, + .me = THIS_MODULE, +}; + +static int __init connlimit_mt_init(void) +{ + return xt_register_match(&connlimit_mt_reg); +} + +static void __exit connlimit_mt_exit(void) +{ + xt_unregister_match(&connlimit_mt_reg); +} + +module_init(connlimit_mt_init); +module_exit(connlimit_mt_exit); +MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); +MODULE_DESCRIPTION("Xtables: Number of connections matching"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("ipt_connlimit"); +MODULE_ALIAS("ip6t_connlimit"); |