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 | e00b437b | 2014-03-20 11:53:39 +0100 | [diff] [blame] | 35 | #define CONNLIMIT_SLOTS 256U |
| 36 | |
| 37 | #ifdef CONFIG_LOCKDEP |
| 38 | #define CONNLIMIT_LOCK_SLOTS 8U |
| 39 | #else |
| 40 | #define CONNLIMIT_LOCK_SLOTS 256U |
| 41 | #endif |
| 42 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 43 | #define CONNLIMIT_GC_MAX_NODES 8 |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 44 | |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 45 | /* we will save the tuples of all connections we care about */ |
| 46 | struct xt_connlimit_conn { |
Changli Gao | 3e0d514 | 2011-03-15 13:25:42 +0100 | [diff] [blame] | 47 | struct hlist_node node; |
Changli Gao | 8183e3a | 2011-03-15 13:23:28 +0100 | [diff] [blame] | 48 | struct nf_conntrack_tuple tuple; |
| 49 | union nf_inet_addr addr; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 50 | }; |
| 51 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 52 | struct xt_connlimit_rb { |
| 53 | struct rb_node node; |
| 54 | struct hlist_head hhead; /* connections/hosts in same subnet */ |
| 55 | union nf_inet_addr addr; /* search key */ |
| 56 | }; |
| 57 | |
Florian Westphal | e00b437b | 2014-03-20 11:53:39 +0100 | [diff] [blame] | 58 | static spinlock_t xt_connlimit_locks[CONNLIMIT_LOCK_SLOTS] __cacheline_aligned_in_smp; |
| 59 | |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 60 | struct xt_connlimit_data { |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 61 | struct rb_root climit_root4[CONNLIMIT_SLOTS]; |
| 62 | struct rb_root climit_root6[CONNLIMIT_SLOTS]; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 63 | }; |
| 64 | |
Jan Engelhardt | 294188a | 2010-01-04 16:28:38 +0100 | [diff] [blame] | 65 | static u_int32_t connlimit_rnd __read_mostly; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 66 | static struct kmem_cache *connlimit_rb_cachep __read_mostly; |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 67 | static struct kmem_cache *connlimit_conn_cachep __read_mostly; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 68 | |
Al Viro | a34c458 | 2007-07-26 17:33:19 +0100 | [diff] [blame] | 69 | static inline unsigned int connlimit_iphash(__be32 addr) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 70 | { |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 71 | return jhash_1word((__force __u32)addr, |
| 72 | connlimit_rnd) % CONNLIMIT_SLOTS; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 73 | } |
| 74 | |
| 75 | static inline unsigned int |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 76 | connlimit_iphash6(const union nf_inet_addr *addr, |
| 77 | const union nf_inet_addr *mask) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 78 | { |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 79 | union nf_inet_addr res; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 80 | unsigned int i; |
| 81 | |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 82 | for (i = 0; i < ARRAY_SIZE(addr->ip6); ++i) |
| 83 | res.ip6[i] = addr->ip6[i] & mask->ip6[i]; |
| 84 | |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 85 | return jhash2((u32 *)res.ip6, ARRAY_SIZE(res.ip6), |
| 86 | connlimit_rnd) % CONNLIMIT_SLOTS; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 87 | } |
| 88 | |
| 89 | static inline bool already_closed(const struct nf_conn *conn) |
| 90 | { |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 91 | if (nf_ct_protonum(conn) == IPPROTO_TCP) |
Dong Wei | d2ee3f2 | 2008-06-04 09:57:51 -0700 | [diff] [blame] | 92 | return conn->proto.tcp.state == TCP_CONNTRACK_TIME_WAIT || |
| 93 | conn->proto.tcp.state == TCP_CONNTRACK_CLOSE; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 94 | else |
| 95 | return 0; |
| 96 | } |
| 97 | |
Florian Westphal | 50e0e9b | 2014-03-12 23:49:50 +0100 | [diff] [blame] | 98 | static int |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 99 | same_source_net(const union nf_inet_addr *addr, |
| 100 | const union nf_inet_addr *mask, |
Jan Engelhardt | 76108ce | 2008-10-08 11:35:00 +0200 | [diff] [blame] | 101 | const union nf_inet_addr *u3, u_int8_t family) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 102 | { |
Jan Engelhardt | ee999d8 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 103 | if (family == NFPROTO_IPV4) { |
Florian Westphal | 50e0e9b | 2014-03-12 23:49:50 +0100 | [diff] [blame] | 104 | return ntohl(addr->ip & mask->ip) - |
| 105 | ntohl(u3->ip & mask->ip); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 106 | } else { |
Jan Engelhardt | 643a2c1 | 2007-12-17 22:43:50 -0800 | [diff] [blame] | 107 | union nf_inet_addr lh, rh; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 108 | unsigned int i; |
| 109 | |
| 110 | for (i = 0; i < ARRAY_SIZE(addr->ip6); ++i) { |
| 111 | lh.ip6[i] = addr->ip6[i] & mask->ip6[i]; |
| 112 | rh.ip6[i] = u3->ip6[i] & mask->ip6[i]; |
| 113 | } |
| 114 | |
Florian Westphal | 50e0e9b | 2014-03-12 23:49:50 +0100 | [diff] [blame] | 115 | return memcmp(&lh.ip6, &rh.ip6, sizeof(lh.ip6)); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 116 | } |
| 117 | } |
| 118 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 119 | static bool add_hlist(struct hlist_head *head, |
| 120 | const struct nf_conntrack_tuple *tuple, |
| 121 | const union nf_inet_addr *addr) |
| 122 | { |
| 123 | struct xt_connlimit_conn *conn; |
| 124 | |
| 125 | conn = kmem_cache_alloc(connlimit_conn_cachep, GFP_ATOMIC); |
| 126 | if (conn == NULL) |
| 127 | return false; |
| 128 | conn->tuple = *tuple; |
| 129 | conn->addr = *addr; |
| 130 | hlist_add_head(&conn->node, head); |
| 131 | return true; |
| 132 | } |
| 133 | |
| 134 | static unsigned int check_hlist(struct net *net, |
| 135 | struct hlist_head *head, |
| 136 | const struct nf_conntrack_tuple *tuple, |
Daniel Borkmann | 308ac91 | 2015-08-08 21:40:01 +0200 | [diff] [blame] | 137 | const struct nf_conntrack_zone *zone, |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 138 | bool *addit) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 139 | { |
Jan Engelhardt | 3cf93c9 | 2008-04-14 09:56:05 +0200 | [diff] [blame] | 140 | const struct nf_conntrack_tuple_hash *found; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 141 | struct xt_connlimit_conn *conn; |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 142 | struct hlist_node *n; |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 143 | struct nf_conn *found_ct; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 144 | unsigned int length = 0; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 145 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 146 | *addit = true; |
Patrick McHardy | 76507f6 | 2008-01-31 04:38:38 -0800 | [diff] [blame] | 147 | rcu_read_lock(); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 148 | |
| 149 | /* check the saved connections */ |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 150 | hlist_for_each_entry_safe(conn, n, head, node) { |
Florian Westphal | e59ea3d | 2014-11-14 13:21:48 +0100 | [diff] [blame] | 151 | found = nf_conntrack_find_get(net, zone, &conn->tuple); |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 152 | if (found == NULL) { |
| 153 | hlist_del(&conn->node); |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 154 | kmem_cache_free(connlimit_conn_cachep, conn); |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 155 | continue; |
| 156 | } |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 157 | |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 158 | found_ct = nf_ct_tuplehash_to_ctrack(found); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 159 | |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 160 | if (nf_ct_tuple_equal(&conn->tuple, tuple)) { |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 161 | /* |
| 162 | * Just to be sure we have it only once in the list. |
| 163 | * We should not see tuples twice unless someone hooks |
| 164 | * this into a table without "-p tcp --syn". |
| 165 | */ |
Florian Westphal | 3bcc5fd | 2014-03-07 14:37:11 +0100 | [diff] [blame] | 166 | *addit = false; |
Florian Westphal | d9ec4f1 | 2014-03-07 14:37:10 +0100 | [diff] [blame] | 167 | } else if (already_closed(found_ct)) { |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 168 | /* |
| 169 | * we do not care about connections which are |
| 170 | * closed already -> ditch it |
| 171 | */ |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 172 | nf_ct_put(found_ct); |
Changli Gao | 3e0d514 | 2011-03-15 13:25:42 +0100 | [diff] [blame] | 173 | hlist_del(&conn->node); |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 174 | kmem_cache_free(connlimit_conn_cachep, conn); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 175 | continue; |
| 176 | } |
| 177 | |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 178 | nf_ct_put(found_ct); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 179 | length++; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 180 | } |
| 181 | |
Patrick McHardy | 76507f6 | 2008-01-31 04:38:38 -0800 | [diff] [blame] | 182 | rcu_read_unlock(); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 183 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 184 | return length; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 185 | } |
| 186 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 187 | static void tree_nodes_free(struct rb_root *root, |
| 188 | struct xt_connlimit_rb *gc_nodes[], |
| 189 | unsigned int gc_count) |
Florian Westphal | 3bcc5fd | 2014-03-07 14:37:11 +0100 | [diff] [blame] | 190 | { |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 191 | struct xt_connlimit_rb *rbconn; |
| 192 | |
| 193 | while (gc_count) { |
| 194 | rbconn = gc_nodes[--gc_count]; |
| 195 | rb_erase(&rbconn->node, root); |
| 196 | kmem_cache_free(connlimit_rb_cachep, rbconn); |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | static unsigned int |
| 201 | count_tree(struct net *net, struct rb_root *root, |
| 202 | const struct nf_conntrack_tuple *tuple, |
| 203 | const union nf_inet_addr *addr, const union nf_inet_addr *mask, |
Daniel Borkmann | 308ac91 | 2015-08-08 21:40:01 +0200 | [diff] [blame] | 204 | u8 family, const struct nf_conntrack_zone *zone) |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 205 | { |
| 206 | struct xt_connlimit_rb *gc_nodes[CONNLIMIT_GC_MAX_NODES]; |
| 207 | struct rb_node **rbnode, *parent; |
| 208 | struct xt_connlimit_rb *rbconn; |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 209 | struct xt_connlimit_conn *conn; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 210 | unsigned int gc_count; |
| 211 | bool no_gc = false; |
| 212 | |
| 213 | restart: |
| 214 | gc_count = 0; |
| 215 | parent = NULL; |
| 216 | rbnode = &(root->rb_node); |
| 217 | while (*rbnode) { |
| 218 | int diff; |
| 219 | bool addit; |
| 220 | |
| 221 | rbconn = container_of(*rbnode, struct xt_connlimit_rb, node); |
| 222 | |
| 223 | parent = *rbnode; |
| 224 | diff = same_source_net(addr, mask, &rbconn->addr, family); |
| 225 | if (diff < 0) { |
| 226 | rbnode = &((*rbnode)->rb_left); |
| 227 | } else if (diff > 0) { |
| 228 | rbnode = &((*rbnode)->rb_right); |
| 229 | } else { |
| 230 | /* same source network -> be counted! */ |
| 231 | unsigned int count; |
Florian Westphal | e59ea3d | 2014-11-14 13:21:48 +0100 | [diff] [blame] | 232 | count = check_hlist(net, &rbconn->hhead, tuple, zone, &addit); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 233 | |
| 234 | tree_nodes_free(root, gc_nodes, gc_count); |
| 235 | if (!addit) |
| 236 | return count; |
| 237 | |
| 238 | if (!add_hlist(&rbconn->hhead, tuple, addr)) |
| 239 | return 0; /* hotdrop */ |
| 240 | |
| 241 | return count + 1; |
| 242 | } |
| 243 | |
| 244 | if (no_gc || gc_count >= ARRAY_SIZE(gc_nodes)) |
| 245 | continue; |
| 246 | |
| 247 | /* only used for GC on hhead, retval and 'addit' ignored */ |
Florian Westphal | e59ea3d | 2014-11-14 13:21:48 +0100 | [diff] [blame] | 248 | check_hlist(net, &rbconn->hhead, tuple, zone, &addit); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 249 | if (hlist_empty(&rbconn->hhead)) |
| 250 | gc_nodes[gc_count++] = rbconn; |
| 251 | } |
| 252 | |
| 253 | if (gc_count) { |
| 254 | no_gc = true; |
| 255 | tree_nodes_free(root, gc_nodes, gc_count); |
| 256 | /* tree_node_free before new allocation permits |
| 257 | * allocator to re-use newly free'd object. |
| 258 | * |
| 259 | * This is a rare event; in most cases we will find |
| 260 | * existing node to re-use. (or gc_count is 0). |
| 261 | */ |
| 262 | goto restart; |
| 263 | } |
| 264 | |
| 265 | /* no match, need to insert new node */ |
| 266 | rbconn = kmem_cache_alloc(connlimit_rb_cachep, GFP_ATOMIC); |
| 267 | if (rbconn == NULL) |
| 268 | return 0; |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 269 | |
| 270 | conn = kmem_cache_alloc(connlimit_conn_cachep, GFP_ATOMIC); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 271 | if (conn == NULL) { |
| 272 | kmem_cache_free(connlimit_rb_cachep, rbconn); |
| 273 | return 0; |
| 274 | } |
| 275 | |
Florian Westphal | 3bcc5fd | 2014-03-07 14:37:11 +0100 | [diff] [blame] | 276 | conn->tuple = *tuple; |
| 277 | conn->addr = *addr; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 278 | rbconn->addr = *addr; |
| 279 | |
| 280 | INIT_HLIST_HEAD(&rbconn->hhead); |
| 281 | hlist_add_head(&conn->node, &rbconn->hhead); |
| 282 | |
| 283 | rb_link_node(&rbconn->node, parent, rbnode); |
| 284 | rb_insert_color(&rbconn->node, root); |
| 285 | return 1; |
Florian Westphal | 3bcc5fd | 2014-03-07 14:37:11 +0100 | [diff] [blame] | 286 | } |
| 287 | |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 288 | static int count_them(struct net *net, |
| 289 | struct xt_connlimit_data *data, |
| 290 | const struct nf_conntrack_tuple *tuple, |
| 291 | const union nf_inet_addr *addr, |
| 292 | const union nf_inet_addr *mask, |
Daniel Borkmann | 308ac91 | 2015-08-08 21:40:01 +0200 | [diff] [blame] | 293 | u_int8_t family, |
| 294 | const struct nf_conntrack_zone *zone) |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 295 | { |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 296 | struct rb_root *root; |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 297 | int count; |
| 298 | u32 hash; |
| 299 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 300 | if (family == NFPROTO_IPV6) { |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 301 | hash = connlimit_iphash6(addr, mask); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 302 | root = &data->climit_root6[hash]; |
| 303 | } else { |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 304 | hash = connlimit_iphash(addr->ip & mask->ip); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 305 | root = &data->climit_root4[hash]; |
| 306 | } |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 307 | |
Florian Westphal | e00b437b | 2014-03-20 11:53:39 +0100 | [diff] [blame] | 308 | spin_lock_bh(&xt_connlimit_locks[hash % CONNLIMIT_LOCK_SLOTS]); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 309 | |
Florian Westphal | e59ea3d | 2014-11-14 13:21:48 +0100 | [diff] [blame] | 310 | count = count_tree(net, root, tuple, addr, mask, family, zone); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 311 | |
Florian Westphal | e00b437b | 2014-03-20 11:53:39 +0100 | [diff] [blame] | 312 | spin_unlock_bh(&xt_connlimit_locks[hash % CONNLIMIT_LOCK_SLOTS]); |
Florian Westphal | 15cfd52 | 2014-03-07 14:37:09 +0100 | [diff] [blame] | 313 | |
| 314 | return count; |
| 315 | } |
| 316 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 317 | static bool |
Jan Engelhardt | 62fc805 | 2009-07-07 20:42:08 +0200 | [diff] [blame] | 318 | connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 319 | { |
Eric W. Biederman | 686c9b5 | 2015-09-18 14:32:59 -0500 | [diff] [blame] | 320 | struct net *net = par->net; |
Jan Engelhardt | f7108a2 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 321 | const struct xt_connlimit_info *info = par->matchinfo; |
Jan Engelhardt | 22c2d8b | 2007-12-17 22:44:47 -0800 | [diff] [blame] | 322 | union nf_inet_addr addr; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 323 | struct nf_conntrack_tuple tuple; |
| 324 | const struct nf_conntrack_tuple *tuple_ptr = &tuple; |
Daniel Borkmann | 308ac91 | 2015-08-08 21:40:01 +0200 | [diff] [blame] | 325 | const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 326 | enum ip_conntrack_info ctinfo; |
| 327 | const struct nf_conn *ct; |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 328 | unsigned int connections; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 329 | |
| 330 | ct = nf_ct_get(skb, &ctinfo); |
Florian Westphal | e59ea3d | 2014-11-14 13:21:48 +0100 | [diff] [blame] | 331 | if (ct != NULL) { |
Changli Gao | 8183e3a | 2011-03-15 13:23:28 +0100 | [diff] [blame] | 332 | tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; |
Florian Westphal | e59ea3d | 2014-11-14 13:21:48 +0100 | [diff] [blame] | 333 | zone = nf_ct_zone(ct); |
| 334 | } else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), |
Eric W. Biederman | a31f1ad | 2015-09-18 14:33:04 -0500 | [diff] [blame] | 335 | par->family, net, &tuple)) { |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 336 | goto hotdrop; |
Florian Westphal | e59ea3d | 2014-11-14 13:21:48 +0100 | [diff] [blame] | 337 | } |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 338 | |
Jan Engelhardt | 92f3b2b | 2008-10-08 11:35:20 +0200 | [diff] [blame] | 339 | if (par->family == NFPROTO_IPV6) { |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 340 | const struct ipv6hdr *iph = ipv6_hdr(skb); |
Jan Engelhardt | cc4fc02 | 2011-01-18 17:32:40 +0100 | [diff] [blame] | 341 | memcpy(&addr.ip6, (info->flags & XT_CONNLIMIT_DADDR) ? |
| 342 | &iph->daddr : &iph->saddr, sizeof(addr.ip6)); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 343 | } else { |
| 344 | const struct iphdr *iph = ip_hdr(skb); |
Jan Engelhardt | cc4fc02 | 2011-01-18 17:32:40 +0100 | [diff] [blame] | 345 | addr.ip = (info->flags & XT_CONNLIMIT_DADDR) ? |
| 346 | iph->daddr : iph->saddr; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 347 | } |
| 348 | |
Alexey Dobriyan | 83fc810 | 2010-01-18 08:07:50 +0100 | [diff] [blame] | 349 | connections = count_them(net, info->data, tuple_ptr, &addr, |
Florian Westphal | e59ea3d | 2014-11-14 13:21:48 +0100 | [diff] [blame] | 350 | &info->mask, par->family, zone); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 351 | if (connections == 0) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 352 | /* kmalloc failed, drop it entirely */ |
Richard Weinberger | 1cc34c3 | 2011-01-18 01:36:57 +0100 | [diff] [blame] | 353 | goto hotdrop; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 354 | |
Jan Engelhardt | cc4fc02 | 2011-01-18 17:32:40 +0100 | [diff] [blame] | 355 | return (connections > info->limit) ^ |
| 356 | !!(info->flags & XT_CONNLIMIT_INVERT); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 357 | |
| 358 | hotdrop: |
Jan Engelhardt | b4ba261 | 2009-07-07 20:54:30 +0200 | [diff] [blame] | 359 | par->hotdrop = true; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 360 | return false; |
| 361 | } |
| 362 | |
Jan Engelhardt | b0f3845 | 2010-03-19 17:16:42 +0100 | [diff] [blame] | 363 | static int connlimit_mt_check(const struct xt_mtchk_param *par) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 364 | { |
Jan Engelhardt | 9b4fce7 | 2008-10-08 11:35:18 +0200 | [diff] [blame] | 365 | struct xt_connlimit_info *info = par->matchinfo; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 366 | unsigned int i; |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 367 | int ret; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 368 | |
Gao Feng | 7bdc662 | 2016-09-18 10:52:25 +0800 | [diff] [blame^] | 369 | net_get_random_once(&connlimit_rnd, sizeof(connlimit_rnd)); |
Changli Gao | 4656c4d | 2011-03-15 13:26:32 +0100 | [diff] [blame] | 370 | |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 371 | ret = nf_ct_l3proto_try_module_get(par->family); |
| 372 | if (ret < 0) { |
Jan Engelhardt | 8bee4ba | 2010-03-17 16:04:40 +0100 | [diff] [blame] | 373 | pr_info("cannot load conntrack support for " |
| 374 | "address family %u\n", par->family); |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 375 | return ret; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 376 | } |
| 377 | |
| 378 | /* init private data */ |
| 379 | info->data = kmalloc(sizeof(struct xt_connlimit_data), GFP_KERNEL); |
| 380 | if (info->data == NULL) { |
Jan Engelhardt | 92f3b2b | 2008-10-08 11:35:20 +0200 | [diff] [blame] | 381 | nf_ct_l3proto_module_put(par->family); |
Jan Engelhardt | 4a5a5c7 | 2010-03-19 17:32:59 +0100 | [diff] [blame] | 382 | return -ENOMEM; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 383 | } |
| 384 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 385 | for (i = 0; i < ARRAY_SIZE(info->data->climit_root4); ++i) |
| 386 | info->data->climit_root4[i] = RB_ROOT; |
| 387 | for (i = 0; i < ARRAY_SIZE(info->data->climit_root6); ++i) |
| 388 | info->data->climit_root6[i] = RB_ROOT; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 389 | |
Jan Engelhardt | bd414ee | 2010-03-23 16:35:56 +0100 | [diff] [blame] | 390 | return 0; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 391 | } |
| 392 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 393 | static void destroy_tree(struct rb_root *r) |
| 394 | { |
| 395 | struct xt_connlimit_conn *conn; |
| 396 | struct xt_connlimit_rb *rbconn; |
| 397 | struct hlist_node *n; |
| 398 | struct rb_node *node; |
| 399 | |
| 400 | while ((node = rb_first(r)) != NULL) { |
| 401 | rbconn = container_of(node, struct xt_connlimit_rb, node); |
| 402 | |
| 403 | rb_erase(node, r); |
| 404 | |
| 405 | hlist_for_each_entry_safe(conn, n, &rbconn->hhead, node) |
| 406 | kmem_cache_free(connlimit_conn_cachep, conn); |
| 407 | |
| 408 | kmem_cache_free(connlimit_rb_cachep, rbconn); |
| 409 | } |
| 410 | } |
| 411 | |
Jan Engelhardt | 6be3d85 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 412 | static void connlimit_mt_destroy(const struct xt_mtdtor_param *par) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 413 | { |
Jan Engelhardt | 6be3d85 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 414 | const struct xt_connlimit_info *info = par->matchinfo; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 415 | unsigned int i; |
| 416 | |
Jan Engelhardt | 92f3b2b | 2008-10-08 11:35:20 +0200 | [diff] [blame] | 417 | nf_ct_l3proto_module_put(par->family); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 418 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 419 | for (i = 0; i < ARRAY_SIZE(info->data->climit_root4); ++i) |
| 420 | destroy_tree(&info->data->climit_root4[i]); |
| 421 | for (i = 0; i < ARRAY_SIZE(info->data->climit_root6); ++i) |
| 422 | destroy_tree(&info->data->climit_root6[i]); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 423 | |
| 424 | kfree(info->data); |
| 425 | } |
| 426 | |
Cong Wang | 68c07cb | 2012-05-19 04:39:01 +0000 | [diff] [blame] | 427 | static struct xt_match connlimit_mt_reg __read_mostly = { |
| 428 | .name = "connlimit", |
| 429 | .revision = 1, |
| 430 | .family = NFPROTO_UNSPEC, |
| 431 | .checkentry = connlimit_mt_check, |
| 432 | .match = connlimit_mt, |
| 433 | .matchsize = sizeof(struct xt_connlimit_info), |
| 434 | .destroy = connlimit_mt_destroy, |
| 435 | .me = THIS_MODULE, |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 436 | }; |
| 437 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 438 | static int __init connlimit_mt_init(void) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 439 | { |
Florian Westphal | e00b437b | 2014-03-20 11:53:39 +0100 | [diff] [blame] | 440 | int ret, i; |
Florian Westphal | 1442e75 | 2014-03-12 23:49:49 +0100 | [diff] [blame] | 441 | |
| 442 | BUILD_BUG_ON(CONNLIMIT_LOCK_SLOTS > CONNLIMIT_SLOTS); |
| 443 | BUILD_BUG_ON((CONNLIMIT_SLOTS % CONNLIMIT_LOCK_SLOTS) != 0); |
| 444 | |
Florian Westphal | e00b437b | 2014-03-20 11:53:39 +0100 | [diff] [blame] | 445 | for (i = 0; i < CONNLIMIT_LOCK_SLOTS; ++i) |
| 446 | spin_lock_init(&xt_connlimit_locks[i]); |
| 447 | |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 448 | connlimit_conn_cachep = kmem_cache_create("xt_connlimit_conn", |
| 449 | sizeof(struct xt_connlimit_conn), |
| 450 | 0, 0, NULL); |
| 451 | if (!connlimit_conn_cachep) |
| 452 | return -ENOMEM; |
| 453 | |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 454 | connlimit_rb_cachep = kmem_cache_create("xt_connlimit_rb", |
| 455 | sizeof(struct xt_connlimit_rb), |
| 456 | 0, 0, NULL); |
| 457 | if (!connlimit_rb_cachep) { |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 458 | kmem_cache_destroy(connlimit_conn_cachep); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 459 | return -ENOMEM; |
| 460 | } |
| 461 | ret = xt_register_match(&connlimit_mt_reg); |
| 462 | if (ret != 0) { |
| 463 | kmem_cache_destroy(connlimit_conn_cachep); |
| 464 | kmem_cache_destroy(connlimit_rb_cachep); |
| 465 | } |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 466 | return ret; |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 467 | } |
| 468 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 469 | static void __exit connlimit_mt_exit(void) |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 470 | { |
Cong Wang | 68c07cb | 2012-05-19 04:39:01 +0000 | [diff] [blame] | 471 | xt_unregister_match(&connlimit_mt_reg); |
Florian Westphal | 14e1a97 | 2014-03-07 14:37:12 +0100 | [diff] [blame] | 472 | kmem_cache_destroy(connlimit_conn_cachep); |
Florian Westphal | 7d08487 | 2014-03-12 23:49:51 +0100 | [diff] [blame] | 473 | kmem_cache_destroy(connlimit_rb_cachep); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 474 | } |
| 475 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 476 | module_init(connlimit_mt_init); |
| 477 | module_exit(connlimit_mt_exit); |
Jan Engelhardt | 92f3b2b | 2008-10-08 11:35:20 +0200 | [diff] [blame] | 478 | MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 479 | MODULE_DESCRIPTION("Xtables: Number of connections matching"); |
Jan Engelhardt | 370786f | 2007-07-14 20:47:26 -0700 | [diff] [blame] | 480 | MODULE_LICENSE("GPL"); |
| 481 | MODULE_ALIAS("ipt_connlimit"); |
| 482 | MODULE_ALIAS("ip6t_connlimit"); |