lis3: add support for the HP EliteBook 8530w
[linux-2.6/mini2440.git] / net / netfilter / xt_connlimit.c
blob6809809543951a635ad3f53ad625dd6287e20220
1 /*
2 * netfilter module to limit the number of parallel tcp
3 * connections per IP address.
4 * (c) 2000 Gerd Knorr <kraxel@bytesex.org>
5 * Nov 2002: Martin Bene <martin.bene@icomedias.com>:
6 * only ignore TIME_WAIT or gone connections
7 * (C) CC Computer Consultants GmbH, 2007
8 * Contact: <jengelh@computergmbh.de>
10 * based on ...
12 * Kernel module to match connection tracking information.
13 * GPL (C) 1999 Rusty Russell (rusty@rustcorp.com.au).
15 #include <linux/in.h>
16 #include <linux/in6.h>
17 #include <linux/ip.h>
18 #include <linux/ipv6.h>
19 #include <linux/jhash.h>
20 #include <linux/list.h>
21 #include <linux/module.h>
22 #include <linux/random.h>
23 #include <linux/skbuff.h>
24 #include <linux/spinlock.h>
25 #include <linux/netfilter/nf_conntrack_tcp.h>
26 #include <linux/netfilter/x_tables.h>
27 #include <linux/netfilter/xt_connlimit.h>
28 #include <net/netfilter/nf_conntrack.h>
29 #include <net/netfilter/nf_conntrack_core.h>
30 #include <net/netfilter/nf_conntrack_tuple.h>
32 /* we will save the tuples of all connections we care about */
33 struct xt_connlimit_conn {
34 struct list_head list;
35 struct nf_conntrack_tuple tuple;
38 struct xt_connlimit_data {
39 struct list_head iphash[256];
40 spinlock_t lock;
43 static u_int32_t connlimit_rnd;
44 static bool connlimit_rnd_inited;
46 static inline unsigned int connlimit_iphash(__be32 addr)
48 if (unlikely(!connlimit_rnd_inited)) {
49 get_random_bytes(&connlimit_rnd, sizeof(connlimit_rnd));
50 connlimit_rnd_inited = true;
52 return jhash_1word((__force __u32)addr, connlimit_rnd) & 0xFF;
55 static inline unsigned int
56 connlimit_iphash6(const union nf_inet_addr *addr,
57 const union nf_inet_addr *mask)
59 union nf_inet_addr res;
60 unsigned int i;
62 if (unlikely(!connlimit_rnd_inited)) {
63 get_random_bytes(&connlimit_rnd, sizeof(connlimit_rnd));
64 connlimit_rnd_inited = true;
67 for (i = 0; i < ARRAY_SIZE(addr->ip6); ++i)
68 res.ip6[i] = addr->ip6[i] & mask->ip6[i];
70 return jhash2((u32 *)res.ip6, ARRAY_SIZE(res.ip6), connlimit_rnd) & 0xFF;
73 static inline bool already_closed(const struct nf_conn *conn)
75 if (nf_ct_protonum(conn) == IPPROTO_TCP)
76 return conn->proto.tcp.state == TCP_CONNTRACK_TIME_WAIT ||
77 conn->proto.tcp.state == TCP_CONNTRACK_CLOSE;
78 else
79 return 0;
82 static inline unsigned int
83 same_source_net(const union nf_inet_addr *addr,
84 const union nf_inet_addr *mask,
85 const union nf_inet_addr *u3, u_int8_t family)
87 if (family == NFPROTO_IPV4) {
88 return (addr->ip & mask->ip) == (u3->ip & mask->ip);
89 } else {
90 union nf_inet_addr lh, rh;
91 unsigned int i;
93 for (i = 0; i < ARRAY_SIZE(addr->ip6); ++i) {
94 lh.ip6[i] = addr->ip6[i] & mask->ip6[i];
95 rh.ip6[i] = u3->ip6[i] & mask->ip6[i];
98 return memcmp(&lh.ip6, &rh.ip6, sizeof(lh.ip6)) == 0;
102 static int count_them(struct xt_connlimit_data *data,
103 const struct nf_conntrack_tuple *tuple,
104 const union nf_inet_addr *addr,
105 const union nf_inet_addr *mask,
106 const struct xt_match *match)
108 const struct nf_conntrack_tuple_hash *found;
109 struct xt_connlimit_conn *conn;
110 struct xt_connlimit_conn *tmp;
111 struct nf_conn *found_ct;
112 struct list_head *hash;
113 bool addit = true;
114 int matches = 0;
117 if (match->family == NFPROTO_IPV6)
118 hash = &data->iphash[connlimit_iphash6(addr, mask)];
119 else
120 hash = &data->iphash[connlimit_iphash(addr->ip & mask->ip)];
122 rcu_read_lock();
124 /* check the saved connections */
125 list_for_each_entry_safe(conn, tmp, hash, list) {
126 found = nf_conntrack_find_get(&init_net, &conn->tuple);
127 found_ct = NULL;
129 if (found != NULL)
130 found_ct = nf_ct_tuplehash_to_ctrack(found);
132 if (found_ct != NULL &&
133 nf_ct_tuple_equal(&conn->tuple, tuple) &&
134 !already_closed(found_ct))
136 * Just to be sure we have it only once in the list.
137 * We should not see tuples twice unless someone hooks
138 * this into a table without "-p tcp --syn".
140 addit = false;
142 if (found == NULL) {
143 /* this one is gone */
144 list_del(&conn->list);
145 kfree(conn);
146 continue;
149 if (already_closed(found_ct)) {
151 * we do not care about connections which are
152 * closed already -> ditch it
154 nf_ct_put(found_ct);
155 list_del(&conn->list);
156 kfree(conn);
157 continue;
160 if (same_source_net(addr, mask, &conn->tuple.src.u3,
161 match->family))
162 /* same source network -> be counted! */
163 ++matches;
164 nf_ct_put(found_ct);
167 rcu_read_unlock();
169 if (addit) {
170 /* save the new connection in our list */
171 conn = kzalloc(sizeof(*conn), GFP_ATOMIC);
172 if (conn == NULL)
173 return -ENOMEM;
174 conn->tuple = *tuple;
175 list_add(&conn->list, hash);
176 ++matches;
179 return matches;
182 static bool
183 connlimit_mt(const struct sk_buff *skb, const struct xt_match_param *par)
185 const struct xt_connlimit_info *info = par->matchinfo;
186 union nf_inet_addr addr;
187 struct nf_conntrack_tuple tuple;
188 const struct nf_conntrack_tuple *tuple_ptr = &tuple;
189 enum ip_conntrack_info ctinfo;
190 const struct nf_conn *ct;
191 int connections;
193 ct = nf_ct_get(skb, &ctinfo);
194 if (ct != NULL)
195 tuple_ptr = &ct->tuplehash[0].tuple;
196 else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
197 par->family, &tuple))
198 goto hotdrop;
200 if (par->family == NFPROTO_IPV6) {
201 const struct ipv6hdr *iph = ipv6_hdr(skb);
202 memcpy(&addr.ip6, &iph->saddr, sizeof(iph->saddr));
203 } else {
204 const struct iphdr *iph = ip_hdr(skb);
205 addr.ip = iph->saddr;
208 spin_lock_bh(&info->data->lock);
209 connections = count_them(info->data, tuple_ptr, &addr,
210 &info->mask, par->match);
211 spin_unlock_bh(&info->data->lock);
213 if (connections < 0) {
214 /* kmalloc failed, drop it entirely */
215 *par->hotdrop = true;
216 return false;
219 return (connections > info->limit) ^ info->inverse;
221 hotdrop:
222 *par->hotdrop = true;
223 return false;
226 static bool connlimit_mt_check(const struct xt_mtchk_param *par)
228 struct xt_connlimit_info *info = par->matchinfo;
229 unsigned int i;
231 if (nf_ct_l3proto_try_module_get(par->family) < 0) {
232 printk(KERN_WARNING "cannot load conntrack support for "
233 "address family %u\n", par->family);
234 return false;
237 /* init private data */
238 info->data = kmalloc(sizeof(struct xt_connlimit_data), GFP_KERNEL);
239 if (info->data == NULL) {
240 nf_ct_l3proto_module_put(par->family);
241 return false;
244 spin_lock_init(&info->data->lock);
245 for (i = 0; i < ARRAY_SIZE(info->data->iphash); ++i)
246 INIT_LIST_HEAD(&info->data->iphash[i]);
248 return true;
251 static void connlimit_mt_destroy(const struct xt_mtdtor_param *par)
253 const struct xt_connlimit_info *info = par->matchinfo;
254 struct xt_connlimit_conn *conn;
255 struct xt_connlimit_conn *tmp;
256 struct list_head *hash = info->data->iphash;
257 unsigned int i;
259 nf_ct_l3proto_module_put(par->family);
261 for (i = 0; i < ARRAY_SIZE(info->data->iphash); ++i) {
262 list_for_each_entry_safe(conn, tmp, &hash[i], list) {
263 list_del(&conn->list);
264 kfree(conn);
268 kfree(info->data);
271 static struct xt_match connlimit_mt_reg __read_mostly = {
272 .name = "connlimit",
273 .revision = 0,
274 .family = NFPROTO_UNSPEC,
275 .checkentry = connlimit_mt_check,
276 .match = connlimit_mt,
277 .matchsize = sizeof(struct xt_connlimit_info),
278 .destroy = connlimit_mt_destroy,
279 .me = THIS_MODULE,
282 static int __init connlimit_mt_init(void)
284 return xt_register_match(&connlimit_mt_reg);
287 static void __exit connlimit_mt_exit(void)
289 xt_unregister_match(&connlimit_mt_reg);
292 module_init(connlimit_mt_init);
293 module_exit(connlimit_mt_exit);
294 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
295 MODULE_DESCRIPTION("Xtables: Number of connections matching");
296 MODULE_LICENSE("GPL");
297 MODULE_ALIAS("ipt_connlimit");
298 MODULE_ALIAS("ip6t_connlimit");