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