/* Kernel module to match connection tracking byte counter. * GPL (C) 2002 Martin Devera (devik@cdi.cz). */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/bitops.h> #include <linux/skbuff.h> #include <linux/math64.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter/xt_connbytes.h> #include <net/netfilter/nf_conntrack.h> #include <net/netfilter/nf_conntrack_acct.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); MODULE_DESCRIPTION("Xtables: Number of packets/bytes per connection matching"); MODULE_ALIAS("ipt_connbytes"); MODULE_ALIAS("ip6t_connbytes"); static bool connbytes_mt(const struct sk_buff *skb, struct xt_action_param *par) { const struct xt_connbytes_info *sinfo = par->matchinfo; const struct nf_conn *ct; enum ip_conntrack_info ctinfo; u_int64_t what = 0; /* initialize to make gcc happy */ u_int64_t bytes = 0; u_int64_t pkts = 0; const struct nf_conn_acct *acct; const struct nf_conn_counter *counters; ct = nf_ct_get(skb, &ctinfo); if (!ct) return false; acct = nf_conn_acct_find(ct); if (!acct) return false; counters = acct->counter; switch (sinfo->what) { case XT_CONNBYTES_PKTS: switch (sinfo->direction) { case XT_CONNBYTES_DIR_ORIGINAL: what = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].packets); break; case XT_CONNBYTES_DIR_REPLY: what = atomic64_read(&counters[IP_CT_DIR_REPLY].packets); break; case XT_CONNBYTES_DIR_BOTH: what = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].packets); what += atomic64_read(&counters[IP_CT_DIR_REPLY].packets); break; } break; case XT_CONNBYTES_BYTES: switch (sinfo->direction) { case XT_CONNBYTES_DIR_ORIGINAL: what = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].bytes); break; case XT_CONNBYTES_DIR_REPLY: what = atomic64_read(&counters[IP_CT_DIR_REPLY].bytes); break; case XT_CONNBYTES_DIR_BOTH: what = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].bytes); what += atomic64_read(&counters[IP_CT_DIR_REPLY].bytes); break; } break; case XT_CONNBYTES_AVGPKT: switch (sinfo->direction) { case XT_CONNBYTES_DIR_ORIGINAL: bytes = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].bytes); pkts = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].packets); break; case XT_CONNBYTES_DIR_REPLY: bytes = atomic64_read(&counters[IP_CT_DIR_REPLY].bytes); pkts = atomic64_read(&counters[IP_CT_DIR_REPLY].packets); break; case XT_CONNBYTES_DIR_BOTH: bytes = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].bytes) + atomic64_read(&counters[IP_CT_DIR_REPLY].bytes); pkts = atomic64_read(&counters[IP_CT_DIR_ORIGINAL].packets) + atomic64_read(&counters[IP_CT_DIR_REPLY].packets); break; } if (pkts != 0) what = div64_u64(bytes, pkts); break; } if (sinfo->count.to >= sinfo->count.from) return what <= sinfo->count.to && what >= sinfo->count.from; else /* inverted */ return what < sinfo->count.to || what > sinfo->count.from; } static int connbytes_mt_check(const struct xt_mtchk_param *par) { const struct xt_connbytes_info *sinfo = par->matchinfo; int ret; if (sinfo->what != XT_CONNBYTES_PKTS && sinfo->what != XT_CONNBYTES_BYTES && sinfo->what != XT_CONNBYTES_AVGPKT) return -EINVAL; if (sinfo->direction != XT_CONNBYTES_DIR_ORIGINAL && sinfo->direction != XT_CONNBYTES_DIR_REPLY && sinfo->direction != XT_CONNBYTES_DIR_BOTH) return -EINVAL; ret = nf_ct_l3proto_try_module_get(par->family); if (ret < 0) pr_info("cannot load conntrack support for proto=%u\n", par->family); /* * This filter cannot function correctly unless connection tracking * accounting is enabled, so complain in the hope that someone notices. */ if (!nf_ct_acct_enabled(par->net)) { pr_warning("Forcing CT accounting to be enabled\n"); nf_ct_set_acct(par->net, true); } return ret; } static void connbytes_mt_destroy(const struct xt_mtdtor_param *par) { nf_ct_l3proto_module_put(par->family); } static struct xt_match connbytes_mt_reg __read_mostly = { .name = "connbytes", .revision = 0, .family = NFPROTO_UNSPEC, .checkentry = connbytes_mt_check, .match = connbytes_mt, .destroy = connbytes_mt_destroy, .matchsize = sizeof(struct xt_connbytes_info), .me = THIS_MODULE, }; static int __init connbytes_mt_init(void) { return xt_register_match(&connbytes_mt_reg); } static void __exit connbytes_mt_exit(void) { xt_unregister_match(&connbytes_mt_reg); } module_init(connbytes_mt_init); module_exit(connbytes_mt_exit);