The function signatures for Xtables extensions have grown over time. It involves a lot of typing/replication, and also a bit of stack space even if they are not used. Realize an NFWS2008 idea and pack them into structs. The skb remains outside of the struct so gcc can continue to apply its optimizations. This patch does this for match extensions' match functions. A few ambiguities have also been addressed. The "offset" parameter for example has been renamed to "fragoff" (there are so many different offsets already) and "protoff" to "thoff" (there is more than just one protocol here, so clarify). Signed-off-by: Jan Engelhardt <jengelh@medozas.de> Signed-off-by: Patrick McHardy <kaber@trash.net>
161 lines
4.2 KiB
C
161 lines
4.2 KiB
C
/* Kernel module to match connection tracking byte counter.
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* GPL (C) 2002 Martin Devera (devik@cdi.cz).
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*/
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#include <linux/module.h>
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#include <linux/bitops.h>
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#include <linux/skbuff.h>
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#include <linux/math64.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_connbytes.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_acct.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
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MODULE_DESCRIPTION("Xtables: Number of packets/bytes per connection matching");
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MODULE_ALIAS("ipt_connbytes");
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MODULE_ALIAS("ip6t_connbytes");
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static bool
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connbytes_mt(const struct sk_buff *skb, const struct xt_match_param *par)
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{
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const struct xt_connbytes_info *sinfo = par->matchinfo;
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const struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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u_int64_t what = 0; /* initialize to make gcc happy */
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u_int64_t bytes = 0;
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u_int64_t pkts = 0;
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const struct nf_conn_counter *counters;
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ct = nf_ct_get(skb, &ctinfo);
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if (!ct)
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return false;
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counters = nf_conn_acct_find(ct);
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if (!counters)
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return false;
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switch (sinfo->what) {
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case XT_CONNBYTES_PKTS:
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switch (sinfo->direction) {
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case XT_CONNBYTES_DIR_ORIGINAL:
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what = counters[IP_CT_DIR_ORIGINAL].packets;
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break;
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case XT_CONNBYTES_DIR_REPLY:
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what = counters[IP_CT_DIR_REPLY].packets;
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break;
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case XT_CONNBYTES_DIR_BOTH:
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what = counters[IP_CT_DIR_ORIGINAL].packets;
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what += counters[IP_CT_DIR_REPLY].packets;
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break;
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}
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break;
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case XT_CONNBYTES_BYTES:
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switch (sinfo->direction) {
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case XT_CONNBYTES_DIR_ORIGINAL:
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what = counters[IP_CT_DIR_ORIGINAL].bytes;
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break;
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case XT_CONNBYTES_DIR_REPLY:
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what = counters[IP_CT_DIR_REPLY].bytes;
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break;
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case XT_CONNBYTES_DIR_BOTH:
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what = counters[IP_CT_DIR_ORIGINAL].bytes;
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what += counters[IP_CT_DIR_REPLY].bytes;
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break;
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}
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break;
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case XT_CONNBYTES_AVGPKT:
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switch (sinfo->direction) {
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case XT_CONNBYTES_DIR_ORIGINAL:
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bytes = counters[IP_CT_DIR_ORIGINAL].bytes;
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pkts = counters[IP_CT_DIR_ORIGINAL].packets;
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break;
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case XT_CONNBYTES_DIR_REPLY:
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bytes = counters[IP_CT_DIR_REPLY].bytes;
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pkts = counters[IP_CT_DIR_REPLY].packets;
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break;
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case XT_CONNBYTES_DIR_BOTH:
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bytes = counters[IP_CT_DIR_ORIGINAL].bytes +
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counters[IP_CT_DIR_REPLY].bytes;
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pkts = counters[IP_CT_DIR_ORIGINAL].packets +
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counters[IP_CT_DIR_REPLY].packets;
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break;
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}
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if (pkts != 0)
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what = div64_u64(bytes, pkts);
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break;
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}
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if (sinfo->count.to)
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return what <= sinfo->count.to && what >= sinfo->count.from;
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else
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return what >= sinfo->count.from;
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}
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static bool
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connbytes_mt_check(const char *tablename, const void *ip,
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const struct xt_match *match, void *matchinfo,
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unsigned int hook_mask)
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{
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const struct xt_connbytes_info *sinfo = matchinfo;
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if (sinfo->what != XT_CONNBYTES_PKTS &&
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sinfo->what != XT_CONNBYTES_BYTES &&
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sinfo->what != XT_CONNBYTES_AVGPKT)
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return false;
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if (sinfo->direction != XT_CONNBYTES_DIR_ORIGINAL &&
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sinfo->direction != XT_CONNBYTES_DIR_REPLY &&
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sinfo->direction != XT_CONNBYTES_DIR_BOTH)
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return false;
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if (nf_ct_l3proto_try_module_get(match->family) < 0) {
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printk(KERN_WARNING "can't load conntrack support for "
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"proto=%u\n", match->family);
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return false;
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}
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return true;
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}
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static void
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connbytes_mt_destroy(const struct xt_match *match, void *matchinfo)
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{
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nf_ct_l3proto_module_put(match->family);
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}
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static struct xt_match connbytes_mt_reg[] __read_mostly = {
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{
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.name = "connbytes",
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.family = NFPROTO_IPV4,
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.checkentry = connbytes_mt_check,
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.match = connbytes_mt,
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.destroy = connbytes_mt_destroy,
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.matchsize = sizeof(struct xt_connbytes_info),
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.me = THIS_MODULE
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},
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{
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.name = "connbytes",
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.family = NFPROTO_IPV6,
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.checkentry = connbytes_mt_check,
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.match = connbytes_mt,
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.destroy = connbytes_mt_destroy,
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.matchsize = sizeof(struct xt_connbytes_info),
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.me = THIS_MODULE
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},
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};
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static int __init connbytes_mt_init(void)
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{
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return xt_register_matches(connbytes_mt_reg,
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ARRAY_SIZE(connbytes_mt_reg));
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}
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static void __exit connbytes_mt_exit(void)
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{
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xt_unregister_matches(connbytes_mt_reg, ARRAY_SIZE(connbytes_mt_reg));
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}
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module_init(connbytes_mt_init);
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module_exit(connbytes_mt_exit);
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