Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 1 | /* Helper handling for netfilter. */ |
| 2 | |
| 3 | /* (C) 1999-2001 Paul `Rusty' Russell |
| 4 | * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> |
| 5 | * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/types.h> |
| 13 | #include <linux/netfilter.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/skbuff.h> |
| 16 | #include <linux/vmalloc.h> |
| 17 | #include <linux/stddef.h> |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 18 | #include <linux/random.h> |
| 19 | #include <linux/err.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/netdevice.h> |
Ingo Molnar | 2ba4cc3 | 2008-05-13 15:37:05 +0200 | [diff] [blame] | 22 | #include <linux/rculist.h> |
Alexey Dobriyan | efb9a8c | 2008-11-05 03:03:18 -0800 | [diff] [blame] | 23 | #include <linux/rtnetlink.h> |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 24 | |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 25 | #include <net/netfilter/nf_conntrack.h> |
| 26 | #include <net/netfilter/nf_conntrack_l3proto.h> |
Martin Josefsson | 605dcad | 2006-11-29 02:35:06 +0100 | [diff] [blame] | 27 | #include <net/netfilter/nf_conntrack_l4proto.h> |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 28 | #include <net/netfilter/nf_conntrack_helper.h> |
| 29 | #include <net/netfilter/nf_conntrack_core.h> |
Yasuyuki Kozakai | ceceae1 | 2007-07-07 22:23:42 -0700 | [diff] [blame] | 30 | #include <net/netfilter/nf_conntrack_extend.h> |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 31 | |
Patrick McHardy | 58a3c9b | 2008-01-31 04:36:54 -0800 | [diff] [blame] | 32 | static DEFINE_MUTEX(nf_ct_helper_mutex); |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 33 | static struct hlist_head *nf_ct_helper_hash __read_mostly; |
| 34 | static unsigned int nf_ct_helper_hsize __read_mostly; |
| 35 | static unsigned int nf_ct_helper_count __read_mostly; |
| 36 | static int nf_ct_helper_vmalloc; |
| 37 | |
| 38 | |
| 39 | /* Stupid hash, but collision free for the default registrations of the |
| 40 | * helpers currently in the kernel. */ |
| 41 | static unsigned int helper_hash(const struct nf_conntrack_tuple *tuple) |
| 42 | { |
| 43 | return (((tuple->src.l3num << 8) | tuple->dst.protonum) ^ |
Al Viro | a34c458 | 2007-07-26 17:33:19 +0100 | [diff] [blame] | 44 | (__force __u16)tuple->src.u.all) % nf_ct_helper_hsize; |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 45 | } |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 46 | |
Pablo Neira Ayuso | 226c0c0 | 2008-11-18 11:54:05 +0100 | [diff] [blame] | 47 | static struct nf_conntrack_helper * |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 48 | __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple) |
| 49 | { |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 50 | struct nf_conntrack_helper *helper; |
Patrick McHardy | d4156e8 | 2007-07-07 22:31:32 -0700 | [diff] [blame] | 51 | struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) }; |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 52 | struct hlist_node *n; |
| 53 | unsigned int h; |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 54 | |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 55 | if (!nf_ct_helper_count) |
| 56 | return NULL; |
| 57 | |
| 58 | h = helper_hash(tuple); |
Patrick McHardy | 58a3c9b | 2008-01-31 04:36:54 -0800 | [diff] [blame] | 59 | hlist_for_each_entry_rcu(helper, n, &nf_ct_helper_hash[h], hnode) { |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 60 | if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask)) |
| 61 | return helper; |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 62 | } |
| 63 | return NULL; |
| 64 | } |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 65 | |
| 66 | struct nf_conntrack_helper * |
Patrick McHardy | 794e687 | 2010-02-03 13:41:29 +0100 | [diff] [blame] | 67 | __nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum) |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 68 | { |
| 69 | struct nf_conntrack_helper *h; |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 70 | struct hlist_node *n; |
| 71 | unsigned int i; |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 72 | |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 73 | for (i = 0; i < nf_ct_helper_hsize; i++) { |
Patrick McHardy | 58a3c9b | 2008-01-31 04:36:54 -0800 | [diff] [blame] | 74 | hlist_for_each_entry_rcu(h, n, &nf_ct_helper_hash[i], hnode) { |
Patrick McHardy | 794e687 | 2010-02-03 13:41:29 +0100 | [diff] [blame] | 75 | if (!strcmp(h->name, name) && |
| 76 | h->tuple.src.l3num == l3num && |
| 77 | h->tuple.dst.protonum == protonum) |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 78 | return h; |
| 79 | } |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 80 | } |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 81 | return NULL; |
| 82 | } |
Patrick McHardy | 794e687 | 2010-02-03 13:41:29 +0100 | [diff] [blame] | 83 | EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find); |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 84 | |
Patrick McHardy | 84f3bb9 | 2010-02-03 17:17:06 +0100 | [diff] [blame] | 85 | struct nf_conntrack_helper * |
| 86 | nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum) |
| 87 | { |
| 88 | struct nf_conntrack_helper *h; |
| 89 | |
| 90 | h = __nf_conntrack_helper_find(name, l3num, protonum); |
| 91 | #ifdef CONFIG_MODULES |
| 92 | if (h == NULL) { |
| 93 | if (request_module("nfct-helper-%s", name) == 0) |
| 94 | h = __nf_conntrack_helper_find(name, l3num, protonum); |
| 95 | } |
| 96 | #endif |
| 97 | if (h != NULL && !try_module_get(h->me)) |
| 98 | h = NULL; |
| 99 | |
| 100 | return h; |
| 101 | } |
| 102 | EXPORT_SYMBOL_GPL(nf_conntrack_helper_try_module_get); |
| 103 | |
Patrick McHardy | b560580 | 2007-07-07 22:35:56 -0700 | [diff] [blame] | 104 | struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp) |
| 105 | { |
| 106 | struct nf_conn_help *help; |
| 107 | |
| 108 | help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, gfp); |
| 109 | if (help) |
| 110 | INIT_HLIST_HEAD(&help->expectations); |
| 111 | else |
| 112 | pr_debug("failed to add helper extension area"); |
| 113 | return help; |
| 114 | } |
| 115 | EXPORT_SYMBOL_GPL(nf_ct_helper_ext_add); |
| 116 | |
Patrick McHardy | b2a15a6 | 2010-02-03 14:13:03 +0100 | [diff] [blame] | 117 | int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl, |
| 118 | gfp_t flags) |
Pablo Neira Ayuso | 226c0c0 | 2008-11-18 11:54:05 +0100 | [diff] [blame] | 119 | { |
Patrick McHardy | b2a15a6 | 2010-02-03 14:13:03 +0100 | [diff] [blame] | 120 | struct nf_conntrack_helper *helper = NULL; |
| 121 | struct nf_conn_help *help; |
Pablo Neira Ayuso | 226c0c0 | 2008-11-18 11:54:05 +0100 | [diff] [blame] | 122 | int ret = 0; |
Pablo Neira Ayuso | 226c0c0 | 2008-11-18 11:54:05 +0100 | [diff] [blame] | 123 | |
Patrick McHardy | b2a15a6 | 2010-02-03 14:13:03 +0100 | [diff] [blame] | 124 | if (tmpl != NULL) { |
| 125 | help = nfct_help(tmpl); |
| 126 | if (help != NULL) |
| 127 | helper = help->helper; |
| 128 | } |
| 129 | |
| 130 | help = nfct_help(ct); |
| 131 | if (helper == NULL) |
| 132 | helper = __nf_ct_helper_find(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); |
Pablo Neira Ayuso | 226c0c0 | 2008-11-18 11:54:05 +0100 | [diff] [blame] | 133 | if (helper == NULL) { |
| 134 | if (help) |
| 135 | rcu_assign_pointer(help->helper, NULL); |
| 136 | goto out; |
| 137 | } |
| 138 | |
| 139 | if (help == NULL) { |
| 140 | help = nf_ct_helper_ext_add(ct, flags); |
| 141 | if (help == NULL) { |
| 142 | ret = -ENOMEM; |
| 143 | goto out; |
| 144 | } |
| 145 | } else { |
| 146 | memset(&help->help, 0, sizeof(help->help)); |
| 147 | } |
| 148 | |
| 149 | rcu_assign_pointer(help->helper, helper); |
| 150 | out: |
| 151 | return ret; |
| 152 | } |
| 153 | EXPORT_SYMBOL_GPL(__nf_ct_try_assign_helper); |
| 154 | |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 155 | static inline int unhelp(struct nf_conntrack_tuple_hash *i, |
| 156 | const struct nf_conntrack_helper *me) |
| 157 | { |
| 158 | struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(i); |
| 159 | struct nf_conn_help *help = nfct_help(ct); |
| 160 | |
| 161 | if (help && help->helper == me) { |
| 162 | nf_conntrack_event(IPCT_HELPER, ct); |
Patrick McHarrdy | 3c158f7 | 2007-06-05 12:55:27 -0700 | [diff] [blame] | 163 | rcu_assign_pointer(help->helper, NULL); |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 164 | } |
| 165 | return 0; |
| 166 | } |
| 167 | |
Pablo Neira Ayuso | 9858a3a | 2009-06-13 12:28:22 +0200 | [diff] [blame] | 168 | void nf_ct_helper_destroy(struct nf_conn *ct) |
| 169 | { |
| 170 | struct nf_conn_help *help = nfct_help(ct); |
| 171 | struct nf_conntrack_helper *helper; |
| 172 | |
| 173 | if (help) { |
| 174 | rcu_read_lock(); |
| 175 | helper = rcu_dereference(help->helper); |
| 176 | if (helper && helper->destroy) |
| 177 | helper->destroy(ct); |
| 178 | rcu_read_unlock(); |
| 179 | } |
| 180 | } |
| 181 | |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 182 | int nf_conntrack_helper_register(struct nf_conntrack_helper *me) |
| 183 | { |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 184 | unsigned int h = helper_hash(&me->tuple); |
| 185 | |
Patrick McHardy | 6002f266 | 2008-03-25 20:09:15 -0700 | [diff] [blame] | 186 | BUG_ON(me->expect_policy == NULL); |
| 187 | BUG_ON(me->expect_class_max >= NF_CT_MAX_EXPECT_CLASSES); |
Holger Eitzenberger | af9d32a | 2009-03-25 18:44:01 +0100 | [diff] [blame] | 188 | BUG_ON(strlen(me->name) > NF_CT_HELPER_NAME_LEN - 1); |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 189 | |
Patrick McHardy | 58a3c9b | 2008-01-31 04:36:54 -0800 | [diff] [blame] | 190 | mutex_lock(&nf_ct_helper_mutex); |
| 191 | hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]); |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 192 | nf_ct_helper_count++; |
Patrick McHardy | 58a3c9b | 2008-01-31 04:36:54 -0800 | [diff] [blame] | 193 | mutex_unlock(&nf_ct_helper_mutex); |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 194 | |
| 195 | return 0; |
| 196 | } |
Patrick McHardy | 13b1833 | 2006-12-02 22:11:25 -0800 | [diff] [blame] | 197 | EXPORT_SYMBOL_GPL(nf_conntrack_helper_register); |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 198 | |
Alexey Dobriyan | 6804793 | 2008-10-08 11:35:06 +0200 | [diff] [blame] | 199 | static void __nf_conntrack_helper_unregister(struct nf_conntrack_helper *me, |
| 200 | struct net *net) |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 201 | { |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 202 | struct nf_conntrack_tuple_hash *h; |
Patrick McHardy | 31f1587 | 2007-07-07 22:35:21 -0700 | [diff] [blame] | 203 | struct nf_conntrack_expect *exp; |
Jan Engelhardt | 58c0fb0 | 2008-04-14 11:15:42 +0200 | [diff] [blame] | 204 | const struct hlist_node *n, *next; |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 205 | const struct hlist_nulls_node *nn; |
Patrick McHardy | 31f1587 | 2007-07-07 22:35:21 -0700 | [diff] [blame] | 206 | unsigned int i; |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 207 | |
Alexey Dobriyan | 6804793 | 2008-10-08 11:35:06 +0200 | [diff] [blame] | 208 | /* Get rid of expectations */ |
| 209 | for (i = 0; i < nf_ct_expect_hsize; i++) { |
| 210 | hlist_for_each_entry_safe(exp, n, next, |
| 211 | &net->ct.expect_hash[i], hnode) { |
| 212 | struct nf_conn_help *help = nfct_help(exp->master); |
| 213 | if ((help->helper == me || exp->helper == me) && |
| 214 | del_timer(&exp->timeout)) { |
| 215 | nf_ct_unlink_expect(exp); |
| 216 | nf_ct_expect_put(exp); |
| 217 | } |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | /* Get rid of expecteds, set helpers to NULL. */ |
Patrick McHardy | 38fb0af | 2009-04-15 12:45:08 +0200 | [diff] [blame] | 222 | hlist_nulls_for_each_entry(h, nn, &net->ct.unconfirmed, hnnode) |
Alexey Dobriyan | 6804793 | 2008-10-08 11:35:06 +0200 | [diff] [blame] | 223 | unhelp(h, me); |
Patrick McHardy | d696c7b | 2010-02-08 11:18:07 -0800 | [diff] [blame] | 224 | for (i = 0; i < net->ct.htable_size; i++) { |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 225 | hlist_nulls_for_each_entry(h, nn, &net->ct.hash[i], hnnode) |
Alexey Dobriyan | 6804793 | 2008-10-08 11:35:06 +0200 | [diff] [blame] | 226 | unhelp(h, me); |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) |
| 231 | { |
| 232 | struct net *net; |
| 233 | |
Patrick McHardy | 58a3c9b | 2008-01-31 04:36:54 -0800 | [diff] [blame] | 234 | mutex_lock(&nf_ct_helper_mutex); |
| 235 | hlist_del_rcu(&me->hnode); |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 236 | nf_ct_helper_count--; |
Patrick McHardy | 58a3c9b | 2008-01-31 04:36:54 -0800 | [diff] [blame] | 237 | mutex_unlock(&nf_ct_helper_mutex); |
| 238 | |
| 239 | /* Make sure every nothing is still using the helper unless its a |
| 240 | * connection in the hash. |
| 241 | */ |
| 242 | synchronize_rcu(); |
| 243 | |
Alexey Dobriyan | efb9a8c | 2008-11-05 03:03:18 -0800 | [diff] [blame] | 244 | rtnl_lock(); |
Patrick McHardy | f8ba1af | 2008-01-31 04:38:58 -0800 | [diff] [blame] | 245 | spin_lock_bh(&nf_conntrack_lock); |
Alexey Dobriyan | 6804793 | 2008-10-08 11:35:06 +0200 | [diff] [blame] | 246 | for_each_net(net) |
| 247 | __nf_conntrack_helper_unregister(me, net); |
Patrick McHardy | f8ba1af | 2008-01-31 04:38:58 -0800 | [diff] [blame] | 248 | spin_unlock_bh(&nf_conntrack_lock); |
Alexey Dobriyan | efb9a8c | 2008-11-05 03:03:18 -0800 | [diff] [blame] | 249 | rtnl_unlock(); |
Martin Josefsson | 7e5d03b | 2006-11-29 02:34:59 +0100 | [diff] [blame] | 250 | } |
Patrick McHardy | 13b1833 | 2006-12-02 22:11:25 -0800 | [diff] [blame] | 251 | EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister); |
Yasuyuki Kozakai | ceceae1 | 2007-07-07 22:23:42 -0700 | [diff] [blame] | 252 | |
Patrick McHardy | 61eb310 | 2007-07-07 22:27:06 -0700 | [diff] [blame] | 253 | static struct nf_ct_ext_type helper_extend __read_mostly = { |
Yasuyuki Kozakai | ceceae1 | 2007-07-07 22:23:42 -0700 | [diff] [blame] | 254 | .len = sizeof(struct nf_conn_help), |
| 255 | .align = __alignof__(struct nf_conn_help), |
| 256 | .id = NF_CT_EXT_HELPER, |
| 257 | }; |
| 258 | |
Al Viro | 8d4bc5b | 2007-07-20 16:15:28 +0100 | [diff] [blame] | 259 | int nf_conntrack_helper_init(void) |
Yasuyuki Kozakai | ceceae1 | 2007-07-07 22:23:42 -0700 | [diff] [blame] | 260 | { |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 261 | int err; |
| 262 | |
| 263 | nf_ct_helper_hsize = 1; /* gets rounded up to use one page */ |
| 264 | nf_ct_helper_hash = nf_ct_alloc_hashtable(&nf_ct_helper_hsize, |
Eric Dumazet | ea781f1 | 2009-03-25 21:05:46 +0100 | [diff] [blame] | 265 | &nf_ct_helper_vmalloc, 0); |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 266 | if (!nf_ct_helper_hash) |
| 267 | return -ENOMEM; |
| 268 | |
| 269 | err = nf_ct_extend_register(&helper_extend); |
| 270 | if (err < 0) |
| 271 | goto err1; |
| 272 | |
| 273 | return 0; |
| 274 | |
| 275 | err1: |
| 276 | nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc, |
| 277 | nf_ct_helper_hsize); |
| 278 | return err; |
Yasuyuki Kozakai | ceceae1 | 2007-07-07 22:23:42 -0700 | [diff] [blame] | 279 | } |
| 280 | |
Al Viro | 8d4bc5b | 2007-07-20 16:15:28 +0100 | [diff] [blame] | 281 | void nf_conntrack_helper_fini(void) |
Yasuyuki Kozakai | ceceae1 | 2007-07-07 22:23:42 -0700 | [diff] [blame] | 282 | { |
| 283 | nf_ct_extend_unregister(&helper_extend); |
Patrick McHardy | b8a7fe6 | 2007-07-07 22:36:46 -0700 | [diff] [blame] | 284 | nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc, |
| 285 | nf_ct_helper_hsize); |
Yasuyuki Kozakai | ceceae1 | 2007-07-07 22:23:42 -0700 | [diff] [blame] | 286 | } |