Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 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 |
Jan Engelhardt | ba5dc27 | 2007-11-05 20:35:56 -0800 | [diff] [blame] | 7 | * (C) CC Computer Consultants GmbH, 2007 |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 8 | * |
| 9 | * based on ... |
| 10 | * |
| 11 | * Kernel module to match connection tracking information. |
| 12 | * GPL (C) 1999 Rusty Russell (rusty@rustcorp.com.au). |
| 13 | */ |
Jan Engelhardt | 8bee4ba | 2010-03-17 16:04:40 +0100 | [diff] [blame] | 14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 20 | #include <linux/slab.h> |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 21 | #include <linux/list.h> |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 22 | #include <linux/rbtree.h> |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 23 | #include <linux/module.h> |
| 24 | #include <linux/random.h> |
| 25 | #include <linux/skbuff.h> |
| 26 | #include <linux/spinlock.h> |
| 27 | #include <linux/netfilter/nf_conntrack_tcp.h> |
| 28 | #include <linux/netfilter/x_tables.h> |
| 29 | #include <linux/netfilter/xt_connlimit.h> |
| 30 | #include <net/netfilter/nf_conntrack.h> |
| 31 | #include <net/netfilter/nf_conntrack_core.h> |
| 32 | #include <net/netfilter/nf_conntrack_tuple.h> |
Patrick McHardy | 5d0aa2c | 2010-02-15 18:13:33 +0100 | [diff] [blame] | 33 | #include <net/netfilter/nf_conntrack_zones.h> |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 34 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 35 | #define CONNLIMIT_SLOTS 32 |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 36 | #define CONNLIMIT_LOCK_SLOTS 32 |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 37 | #define CONNLIMIT_GC_MAX_NODES 8 |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 38 | |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 39 | /* we will save the tuples of all connections we care about */ |
| 40 | struct xt_connlimit_conn { |
Changli Gao | 3e0d514 | 2011-03-15 13:25:42 +0100 | [diff] [blame] | 41 | struct hlist_node node; |
Changli Gao | 8183e3a | 2011-03-15 13:23:28 +0100 | [diff] [blame] | 42 | struct nf_conntrack_tuple tuple; |
| 43 | union nf_inet_addr addr; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 44 | }; |
| 45 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 46 | struct xt_connlimit_rb { |
| 47 | struct rb_node node; |
| 48 | struct hlist_head hhead; /* connections/hosts in same subnet */ |
| 49 | union nf_inet_addr addr; /* search key */ |
| 50 | }; |
| 51 | |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 52 | struct xt_connlimit_data { |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 53 | struct rb_root climit_root4[CONNLIMIT_SLOTS]; |
| 54 | struct rb_root climit_root6[CONNLIMIT_SLOTS]; |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 55 | spinlock_t locks[CONNLIMIT_LOCK_SLOTS]; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 56 | }; |
| 57 | |
Jan Engelhardt | 294188a | 2010-01-04 16:28:38 +0100 | [diff] [blame] | 58 | static u_int32_t connlimit_rnd __read_mostly; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 59 | static struct kmem_cache *connlimit_rb_cachep __read_mostly; |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 60 | static struct kmem_cache *connlimit_conn_cachep __read_mostly; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 61 | |
Al Viro | a34c458 | 2007-07-26 17:33:19 +0100 | [diff] [blame] | 62 | static inline unsigned int connlimit_iphash(__be32 addr) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 63 | { |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 64 | return jhash_1word((__force __u32)addr, |
| 65 | connlimit_rnd) % CONNLIMIT_SLOTS; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 66 | } |
| 67 | |
| 68 | static inline unsigned int |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 69 | connlimit_iphash6(const union nf_inet_addr *addr, |
| 70 | const union nf_inet_addr *mask) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 71 | { |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 72 | union nf_inet_addr res; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 73 | unsigned int i; |
| 74 | |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 75 | for (i = 0; i < ARRAY_SIZE(addr->ip6); ++i) |
| 76 | res.ip6[i] = addr->ip6[i] & mask->ip6[i]; |
| 77 | |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 78 | return jhash2((u32 *)res.ip6, ARRAY_SIZE(res.ip6), |
| 79 | connlimit_rnd) % CONNLIMIT_SLOTS; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 80 | } |
| 81 | |
| 82 | static inline bool already_closed(const struct nf_conn *conn) |
| 83 | { |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 84 | if (nf_ct_protonum(conn) == IPPROTO_TCP) |
Dong Wei | d2ee3f2 | 2008-06-04 09:57:51 -0700 | [diff] [blame] | 85 | return conn->proto.tcp.state == TCP_CONNTRACK_TIME_WAIT || |
| 86 | conn->proto.tcp.state == TCP_CONNTRACK_CLOSE; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 87 | else |
| 88 | return 0; |
| 89 | } |
| 90 | |
Florian Westphal | 50e0e9b | 2014-03-12 23:49:50 +0100 | [diff] [blame] | 91 | static int |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 92 | same_source_net(const union nf_inet_addr *addr, |
| 93 | const union nf_inet_addr *mask, |
Jan Engelhardt | 76108ce | 2008-10-08 11:35:00 +0200 | [diff] [blame] | 94 | const union nf_inet_addr *u3, u_int8_t family) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 95 | { |
Jan Engelhardt | ee999d8 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 96 | if (family == NFPROTO_IPV4) { |
Florian Westphal | 50e0e9b | 2014-03-12 23:49:50 +0100 | [diff] [blame] | 97 | return ntohl(addr->ip & mask->ip) - |
| 98 | ntohl(u3->ip & mask->ip); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 99 | } else { |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 100 | union nf_inet_addr lh, rh; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 101 | unsigned int i; |
| 102 | |
| 103 | for (i = 0; i < ARRAY_SIZE(addr->ip6); ++i) { |
| 104 | lh.ip6[i] = addr->ip6[i] & mask->ip6[i]; |
| 105 | rh.ip6[i] = u3->ip6[i] & mask->ip6[i]; |
| 106 | } |
| 107 | |
Florian Westphal | 50e0e9b | 2014-03-12 23:49:50 +0100 | [diff] [blame] | 108 | return memcmp(&lh.ip6, &rh.ip6, sizeof(lh.ip6)); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 109 | } |
| 110 | } |
| 111 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 112 | static bool add_hlist(struct hlist_head *head, |
| 113 | const struct nf_conntrack_tuple *tuple, |
| 114 | const union nf_inet_addr *addr) |
| 115 | { |
| 116 | struct xt_connlimit_conn *conn; |
| 117 | |
| 118 | conn = kmem_cache_alloc(connlimit_conn_cachep, GFP_ATOMIC); |
| 119 | if (conn == NULL) |
| 120 | return false; |
| 121 | conn->tuple = *tuple; |
| 122 | conn->addr = *addr; |
| 123 | hlist_add_head(&conn->node, head); |
| 124 | return true; |
| 125 | } |
| 126 | |
| 127 | static unsigned int check_hlist(struct net *net, |
| 128 | struct hlist_head *head, |
| 129 | const struct nf_conntrack_tuple *tuple, |
| 130 | bool *addit) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 131 | { |
Jan Engelhardt | 3cf93c9 | 2008-04-14 09:56:05 +0200 | [diff] [blame] | 132 | const struct nf_conntrack_tuple_hash *found; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 133 | struct xt_connlimit_conn *conn; |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 134 | struct hlist_node *n; |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 135 | struct nf_conn *found_ct; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 136 | unsigned int length = 0; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 137 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 138 | *addit = true; |
Patrick McHardy | 76507f6 | 2008-01-31 04:38:38 -0800 | [diff] [blame] | 139 | rcu_read_lock(); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 140 | |
| 141 | /* check the saved connections */ |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 142 | hlist_for_each_entry_safe(conn, n, head, node) { |
Patrick McHardy | 5d0aa2c | 2010-02-15 18:13:33 +0100 | [diff] [blame] | 143 | found = nf_conntrack_find_get(net, NF_CT_DEFAULT_ZONE, |
| 144 | &conn->tuple); |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 145 | if (found == NULL) { |
| 146 | hlist_del(&conn->node); |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 147 | kmem_cache_free(connlimit_conn_cachep, conn); |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 148 | continue; |
| 149 | } |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 150 | |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 151 | found_ct = nf_ct_tuplehash_to_ctrack(found); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 152 | |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 153 | if (nf_ct_tuple_equal(&conn->tuple, tuple)) { |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 154 | /* |
| 155 | * Just to be sure we have it only once in the list. |
| 156 | * We should not see tuples twice unless someone hooks |
| 157 | * this into a table without "-p tcp --syn". |
| 158 | */ |
Florian Westphal | 3bcc5fd | 2014-03-07 14:37:11 +0100 | [diff] [blame] | 159 | *addit = false; |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 160 | } else if (already_closed(found_ct)) { |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 161 | /* |
| 162 | * we do not care about connections which are |
| 163 | * closed already -> ditch it |
| 164 | */ |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 165 | nf_ct_put(found_ct); |
Changli Gao | 3e0d514 | 2011-03-15 13:25:42 +0100 | [diff] [blame] | 166 | hlist_del(&conn->node); |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 167 | kmem_cache_free(connlimit_conn_cachep, conn); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 168 | continue; |
| 169 | } |
| 170 | |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 171 | nf_ct_put(found_ct); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 172 | length++; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 173 | } |
| 174 | |
Patrick McHardy | 76507f6 | 2008-01-31 04:38:38 -0800 | [diff] [blame] | 175 | rcu_read_unlock(); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 176 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 177 | return length; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 178 | } |
| 179 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 180 | static void tree_nodes_free(struct rb_root *root, |
| 181 | struct xt_connlimit_rb *gc_nodes[], |
| 182 | unsigned int gc_count) |
Florian Westphal | 3bcc5fd | 2014-03-07 14:37:11 +0100 | [diff] [blame] | 183 | { |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 184 | struct xt_connlimit_rb *rbconn; |
| 185 | |
| 186 | while (gc_count) { |
| 187 | rbconn = gc_nodes[--gc_count]; |
| 188 | rb_erase(&rbconn->node, root); |
| 189 | kmem_cache_free(connlimit_rb_cachep, rbconn); |
| 190 | } |
| 191 | } |
| 192 | |
| 193 | static unsigned int |
| 194 | count_tree(struct net *net, struct rb_root *root, |
| 195 | const struct nf_conntrack_tuple *tuple, |
| 196 | const union nf_inet_addr *addr, const union nf_inet_addr *mask, |
| 197 | u8 family) |
| 198 | { |
| 199 | struct xt_connlimit_rb *gc_nodes[CONNLIMIT_GC_MAX_NODES]; |
| 200 | struct rb_node **rbnode, *parent; |
| 201 | struct xt_connlimit_rb *rbconn; |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 202 | struct xt_connlimit_conn *conn; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 203 | unsigned int gc_count; |
| 204 | bool no_gc = false; |
| 205 | |
| 206 | restart: |
| 207 | gc_count = 0; |
| 208 | parent = NULL; |
| 209 | rbnode = &(root->rb_node); |
| 210 | while (*rbnode) { |
| 211 | int diff; |
| 212 | bool addit; |
| 213 | |
| 214 | rbconn = container_of(*rbnode, struct xt_connlimit_rb, node); |
| 215 | |
| 216 | parent = *rbnode; |
| 217 | diff = same_source_net(addr, mask, &rbconn->addr, family); |
| 218 | if (diff < 0) { |
| 219 | rbnode = &((*rbnode)->rb_left); |
| 220 | } else if (diff > 0) { |
| 221 | rbnode = &((*rbnode)->rb_right); |
| 222 | } else { |
| 223 | /* same source network -> be counted! */ |
| 224 | unsigned int count; |
| 225 | count = check_hlist(net, &rbconn->hhead, tuple, &addit); |
| 226 | |
| 227 | tree_nodes_free(root, gc_nodes, gc_count); |
| 228 | if (!addit) |
| 229 | return count; |
| 230 | |
| 231 | if (!add_hlist(&rbconn->hhead, tuple, addr)) |
| 232 | return 0; /* hotdrop */ |
| 233 | |
| 234 | return count + 1; |
| 235 | } |
| 236 | |
| 237 | if (no_gc || gc_count >= ARRAY_SIZE(gc_nodes)) |
| 238 | continue; |
| 239 | |
| 240 | /* only used for GC on hhead, retval and 'addit' ignored */ |
| 241 | check_hlist(net, &rbconn->hhead, tuple, &addit); |
| 242 | if (hlist_empty(&rbconn->hhead)) |
| 243 | gc_nodes[gc_count++] = rbconn; |
| 244 | } |
| 245 | |
| 246 | if (gc_count) { |
| 247 | no_gc = true; |
| 248 | tree_nodes_free(root, gc_nodes, gc_count); |
| 249 | /* tree_node_free before new allocation permits |
| 250 | * allocator to re-use newly free'd object. |
| 251 | * |
| 252 | * This is a rare event; in most cases we will find |
| 253 | * existing node to re-use. (or gc_count is 0). |
| 254 | */ |
| 255 | goto restart; |
| 256 | } |
| 257 | |
| 258 | /* no match, need to insert new node */ |
| 259 | rbconn = kmem_cache_alloc(connlimit_rb_cachep, GFP_ATOMIC); |
| 260 | if (rbconn == NULL) |
| 261 | return 0; |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 262 | |
| 263 | conn = kmem_cache_alloc(connlimit_conn_cachep, GFP_ATOMIC); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 264 | if (conn == NULL) { |
| 265 | kmem_cache_free(connlimit_rb_cachep, rbconn); |
| 266 | return 0; |
| 267 | } |
| 268 | |
Florian Westphal | 3bcc5fd | 2014-03-07 14:37:11 +0100 | [diff] [blame] | 269 | conn->tuple = *tuple; |
| 270 | conn->addr = *addr; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 271 | rbconn->addr = *addr; |
| 272 | |
| 273 | INIT_HLIST_HEAD(&rbconn->hhead); |
| 274 | hlist_add_head(&conn->node, &rbconn->hhead); |
| 275 | |
| 276 | rb_link_node(&rbconn->node, parent, rbnode); |
| 277 | rb_insert_color(&rbconn->node, root); |
| 278 | return 1; |
Florian Westphal | 3bcc5fd | 2014-03-07 14:37:11 +0100 | [diff] [blame] | 279 | } |
| 280 | |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 281 | static int count_them(struct net *net, |
| 282 | struct xt_connlimit_data *data, |
| 283 | const struct nf_conntrack_tuple *tuple, |
| 284 | const union nf_inet_addr *addr, |
| 285 | const union nf_inet_addr *mask, |
| 286 | u_int8_t family) |
| 287 | { |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 288 | struct rb_root *root; |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 289 | int count; |
| 290 | u32 hash; |
| 291 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 292 | if (family == NFPROTO_IPV6) { |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 293 | hash = connlimit_iphash6(addr, mask); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 294 | root = &data->climit_root6[hash]; |
| 295 | } else { |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 296 | hash = connlimit_iphash(addr->ip & mask->ip); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 297 | root = &data->climit_root4[hash]; |
| 298 | } |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 299 | |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 300 | spin_lock_bh(&data->locks[hash % CONNLIMIT_LOCK_SLOTS]); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 301 | |
| 302 | count = count_tree(net, root, tuple, addr, mask, family); |
| 303 | |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 304 | spin_unlock_bh(&data->locks[hash % CONNLIMIT_LOCK_SLOTS]); |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 305 | |
| 306 | return count; |
| 307 | } |
| 308 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 309 | static bool |
Jan Engelhardt | 62fc805 | 2009-07-07 20:42:08 +0200 | [diff] [blame] | 310 | connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 311 | { |
Alexey Dobriyan | 83fc810 | 2010-01-18 08:07:50 +0100 | [diff] [blame] | 312 | struct net *net = dev_net(par->in ? par->in : par->out); |
Jan Engelhardt | f7108a2 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 313 | const struct xt_connlimit_info *info = par->matchinfo; |
Jan Engelhardt | 22c2d8b | 2007-12-17 22:44:47 -0800 | [diff] [blame] | 314 | union nf_inet_addr addr; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 315 | struct nf_conntrack_tuple tuple; |
| 316 | const struct nf_conntrack_tuple *tuple_ptr = &tuple; |
| 317 | enum ip_conntrack_info ctinfo; |
| 318 | const struct nf_conn *ct; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 319 | unsigned int connections; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 320 | |
| 321 | ct = nf_ct_get(skb, &ctinfo); |
Changli Gao | 8183e3a | 2011-03-15 13:23:28 +0100 | [diff] [blame] | 322 | if (ct != NULL) |
| 323 | tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; |
| 324 | else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), |
| 325 | par->family, &tuple)) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 326 | goto hotdrop; |
| 327 | |
Jan Engelhardt | 92f3b2b | 2008-10-08 11:35:20 +0200 | [diff] [blame] | 328 | if (par->family == NFPROTO_IPV6) { |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 329 | const struct ipv6hdr *iph = ipv6_hdr(skb); |
Jan Engelhardt | cc4fc02 | 2011-01-18 17:32:40 +0100 | [diff] [blame] | 330 | memcpy(&addr.ip6, (info->flags & XT_CONNLIMIT_DADDR) ? |
| 331 | &iph->daddr : &iph->saddr, sizeof(addr.ip6)); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 332 | } else { |
| 333 | const struct iphdr *iph = ip_hdr(skb); |
Jan Engelhardt | cc4fc02 | 2011-01-18 17:32:40 +0100 | [diff] [blame] | 334 | addr.ip = (info->flags & XT_CONNLIMIT_DADDR) ? |
| 335 | iph->daddr : iph->saddr; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 336 | } |
| 337 | |
Alexey Dobriyan | 83fc810 | 2010-01-18 08:07:50 +0100 | [diff] [blame] | 338 | connections = count_them(net, info->data, tuple_ptr, &addr, |
Stefan Berger | 20b7975 | 2011-02-14 16:54:33 +0100 | [diff] [blame] | 339 | &info->mask, par->family); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 340 | if (connections == 0) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 341 | /* kmalloc failed, drop it entirely */ |
Richard Weinberger | 1cc34c3 | 2011-01-18 01:36:57 +0100 | [diff] [blame] | 342 | goto hotdrop; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 343 | |
Jan Engelhardt | cc4fc02 | 2011-01-18 17:32:40 +0100 | [diff] [blame] | 344 | return (connections > info->limit) ^ |
| 345 | !!(info->flags & XT_CONNLIMIT_INVERT); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 346 | |
| 347 | hotdrop: |
Jan Engelhardt | b4ba261 | 2009-07-07 20:54:30 +0200 | [diff] [blame] | 348 | par->hotdrop = true; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 349 | return false; |
| 350 | } |
| 351 | |
Jan Engelhardt | b0f3845 | 2010-03-19 17:16:42 +0100 | [diff] [blame] | 352 | static int connlimit_mt_check(const struct xt_mtchk_param *par) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 353 | { |
Jan Engelhardt | 9b4fce7 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 354 | struct xt_connlimit_info *info = par->matchinfo; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 355 | unsigned int i; |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 356 | int ret; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 357 | |
Changli Gao | 4656c4d | 2011-03-15 13:26:32 +0100 | [diff] [blame] | 358 | if (unlikely(!connlimit_rnd)) { |
| 359 | u_int32_t rand; |
| 360 | |
| 361 | do { |
| 362 | get_random_bytes(&rand, sizeof(rand)); |
| 363 | } while (!rand); |
| 364 | cmpxchg(&connlimit_rnd, 0, rand); |
Jan Engelhardt | 294188a | 2010-01-04 16:28:38 +0100 | [diff] [blame] | 365 | } |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 366 | ret = nf_ct_l3proto_try_module_get(par->family); |
| 367 | if (ret < 0) { |
Jan Engelhardt | 8bee4ba | 2010-03-17 16:04:40 +0100 | [diff] [blame] | 368 | pr_info("cannot load conntrack support for " |
| 369 | "address family %u\n", par->family); |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 370 | return ret; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 371 | } |
| 372 | |
| 373 | /* init private data */ |
| 374 | info->data = kmalloc(sizeof(struct xt_connlimit_data), GFP_KERNEL); |
| 375 | if (info->data == NULL) { |
Jan Engelhardt | 92f3b2b | 2008-10-08 11:35:20 +0200 | [diff] [blame] | 376 | nf_ct_l3proto_module_put(par->family); |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 377 | return -ENOMEM; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 378 | } |
| 379 | |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 380 | for (i = 0; i < ARRAY_SIZE(info->data->locks); ++i) |
| 381 | spin_lock_init(&info->data->locks[i]); |
| 382 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 383 | for (i = 0; i < ARRAY_SIZE(info->data->climit_root4); ++i) |
| 384 | info->data->climit_root4[i] = RB_ROOT; |
| 385 | for (i = 0; i < ARRAY_SIZE(info->data->climit_root6); ++i) |
| 386 | info->data->climit_root6[i] = RB_ROOT; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 387 | |
Jan Engelhardt | bd414ee | 2010-03-23 16:35:56 +0100 | [diff] [blame] | 388 | return 0; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 389 | } |
| 390 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 391 | static void destroy_tree(struct rb_root *r) |
| 392 | { |
| 393 | struct xt_connlimit_conn *conn; |
| 394 | struct xt_connlimit_rb *rbconn; |
| 395 | struct hlist_node *n; |
| 396 | struct rb_node *node; |
| 397 | |
| 398 | while ((node = rb_first(r)) != NULL) { |
| 399 | rbconn = container_of(node, struct xt_connlimit_rb, node); |
| 400 | |
| 401 | rb_erase(node, r); |
| 402 | |
| 403 | hlist_for_each_entry_safe(conn, n, &rbconn->hhead, node) |
| 404 | kmem_cache_free(connlimit_conn_cachep, conn); |
| 405 | |
| 406 | kmem_cache_free(connlimit_rb_cachep, rbconn); |
| 407 | } |
| 408 | } |
| 409 | |
Jan Engelhardt | 6be3d85 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 410 | static void connlimit_mt_destroy(const struct xt_mtdtor_param *par) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 411 | { |
Jan Engelhardt | 6be3d85 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 412 | const struct xt_connlimit_info *info = par->matchinfo; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 413 | unsigned int i; |
| 414 | |
Jan Engelhardt | 92f3b2b | 2008-10-08 11:35:20 +0200 | [diff] [blame] | 415 | nf_ct_l3proto_module_put(par->family); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 416 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 417 | for (i = 0; i < ARRAY_SIZE(info->data->climit_root4); ++i) |
| 418 | destroy_tree(&info->data->climit_root4[i]); |
| 419 | for (i = 0; i < ARRAY_SIZE(info->data->climit_root6); ++i) |
| 420 | destroy_tree(&info->data->climit_root6[i]); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 421 | |
| 422 | kfree(info->data); |
| 423 | } |
| 424 | |
Cong Wang | 68c07cb | 2012-05-19 04:39:01 +0000 | [diff] [blame] | 425 | static struct xt_match connlimit_mt_reg __read_mostly = { |
| 426 | .name = "connlimit", |
| 427 | .revision = 1, |
| 428 | .family = NFPROTO_UNSPEC, |
| 429 | .checkentry = connlimit_mt_check, |
| 430 | .match = connlimit_mt, |
| 431 | .matchsize = sizeof(struct xt_connlimit_info), |
| 432 | .destroy = connlimit_mt_destroy, |
| 433 | .me = THIS_MODULE, |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 434 | }; |
| 435 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 436 | static int __init connlimit_mt_init(void) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 437 | { |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 438 | int ret; |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 439 | |
| 440 | BUILD_BUG_ON(CONNLIMIT_LOCK_SLOTS > CONNLIMIT_SLOTS); |
| 441 | BUILD_BUG_ON((CONNLIMIT_SLOTS % CONNLIMIT_LOCK_SLOTS) != 0); |
| 442 | |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 443 | connlimit_conn_cachep = kmem_cache_create("xt_connlimit_conn", |
| 444 | sizeof(struct xt_connlimit_conn), |
| 445 | 0, 0, NULL); |
| 446 | if (!connlimit_conn_cachep) |
| 447 | return -ENOMEM; |
| 448 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 449 | connlimit_rb_cachep = kmem_cache_create("xt_connlimit_rb", |
| 450 | sizeof(struct xt_connlimit_rb), |
| 451 | 0, 0, NULL); |
| 452 | if (!connlimit_rb_cachep) { |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 453 | kmem_cache_destroy(connlimit_conn_cachep); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 454 | return -ENOMEM; |
| 455 | } |
| 456 | ret = xt_register_match(&connlimit_mt_reg); |
| 457 | if (ret != 0) { |
| 458 | kmem_cache_destroy(connlimit_conn_cachep); |
| 459 | kmem_cache_destroy(connlimit_rb_cachep); |
| 460 | } |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 461 | return ret; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 462 | } |
| 463 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 464 | static void __exit connlimit_mt_exit(void) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 465 | { |
Cong Wang | 68c07cb | 2012-05-19 04:39:01 +0000 | [diff] [blame] | 466 | xt_unregister_match(&connlimit_mt_reg); |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 467 | kmem_cache_destroy(connlimit_conn_cachep); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame^] | 468 | kmem_cache_destroy(connlimit_rb_cachep); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 469 | } |
| 470 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 471 | module_init(connlimit_mt_init); |
| 472 | module_exit(connlimit_mt_exit); |
Jan Engelhardt | 92f3b2b | 2008-10-08 11:35:20 +0200 | [diff] [blame] | 473 | MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 474 | MODULE_DESCRIPTION("Xtables: Number of connections matching"); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 475 | MODULE_LICENSE("GPL"); |
| 476 | MODULE_ALIAS("ipt_connlimit"); |
| 477 | MODULE_ALIAS("ip6t_connlimit"); |