Pablo Neira Ayuso | 5097846 | 2012-02-28 19:13:48 +0100 | [diff] [blame] | 1 | /* |
| 2 | * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org> |
| 3 | * (C) 2012 by Vyatta Inc. <http://www.vyatta.com> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation (or any later at your option). |
| 8 | */ |
| 9 | #include <linux/init.h> |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/rculist.h> |
| 13 | #include <linux/rculist_nulls.h> |
| 14 | #include <linux/types.h> |
| 15 | #include <linux/timer.h> |
| 16 | #include <linux/security.h> |
| 17 | #include <linux/skbuff.h> |
| 18 | #include <linux/errno.h> |
| 19 | #include <linux/netlink.h> |
| 20 | #include <linux/spinlock.h> |
| 21 | #include <linux/interrupt.h> |
| 22 | #include <linux/slab.h> |
| 23 | |
| 24 | #include <linux/netfilter.h> |
| 25 | #include <net/netlink.h> |
| 26 | #include <net/sock.h> |
| 27 | #include <net/netfilter/nf_conntrack.h> |
| 28 | #include <net/netfilter/nf_conntrack_core.h> |
| 29 | #include <net/netfilter/nf_conntrack_l3proto.h> |
| 30 | #include <net/netfilter/nf_conntrack_l4proto.h> |
| 31 | #include <net/netfilter/nf_conntrack_tuple.h> |
Pablo Neira Ayuso | 24de58f | 2012-02-29 02:19:19 +0100 | [diff] [blame^] | 32 | #include <net/netfilter/nf_conntrack_timeout.h> |
Pablo Neira Ayuso | 5097846 | 2012-02-28 19:13:48 +0100 | [diff] [blame] | 33 | |
| 34 | #include <linux/netfilter/nfnetlink.h> |
| 35 | #include <linux/netfilter/nfnetlink_cttimeout.h> |
| 36 | |
| 37 | MODULE_LICENSE("GPL"); |
| 38 | MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); |
| 39 | MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning"); |
| 40 | |
Pablo Neira Ayuso | 5097846 | 2012-02-28 19:13:48 +0100 | [diff] [blame] | 41 | static LIST_HEAD(cttimeout_list); |
| 42 | |
| 43 | static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = { |
| 44 | [CTA_TIMEOUT_NAME] = { .type = NLA_NUL_STRING }, |
| 45 | [CTA_TIMEOUT_L3PROTO] = { .type = NLA_U16 }, |
| 46 | [CTA_TIMEOUT_L4PROTO] = { .type = NLA_U8 }, |
| 47 | [CTA_TIMEOUT_DATA] = { .type = NLA_NESTED }, |
| 48 | }; |
| 49 | |
| 50 | static int |
| 51 | ctnl_timeout_parse_policy(struct ctnl_timeout *timeout, |
| 52 | struct nf_conntrack_l4proto *l4proto, |
| 53 | const struct nlattr *attr) |
| 54 | { |
| 55 | int ret = 0; |
| 56 | |
| 57 | if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) { |
| 58 | struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1]; |
| 59 | |
| 60 | nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max, |
| 61 | attr, l4proto->ctnl_timeout.nla_policy); |
| 62 | |
| 63 | ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, &timeout->data); |
| 64 | } |
| 65 | return ret; |
| 66 | } |
| 67 | |
| 68 | static int |
| 69 | cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb, |
| 70 | const struct nlmsghdr *nlh, |
| 71 | const struct nlattr * const cda[]) |
| 72 | { |
| 73 | __u16 l3num; |
| 74 | __u8 l4num; |
| 75 | struct nf_conntrack_l4proto *l4proto; |
| 76 | struct ctnl_timeout *timeout, *matching = NULL; |
| 77 | char *name; |
| 78 | int ret; |
| 79 | |
| 80 | if (!cda[CTA_TIMEOUT_NAME] || |
| 81 | !cda[CTA_TIMEOUT_L3PROTO] || |
| 82 | !cda[CTA_TIMEOUT_L4PROTO] || |
| 83 | !cda[CTA_TIMEOUT_DATA]) |
| 84 | return -EINVAL; |
| 85 | |
| 86 | name = nla_data(cda[CTA_TIMEOUT_NAME]); |
| 87 | l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO])); |
| 88 | l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]); |
| 89 | |
| 90 | list_for_each_entry(timeout, &cttimeout_list, head) { |
| 91 | if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) |
| 92 | continue; |
| 93 | |
| 94 | if (nlh->nlmsg_flags & NLM_F_EXCL) |
| 95 | return -EEXIST; |
| 96 | |
| 97 | matching = timeout; |
| 98 | break; |
| 99 | } |
| 100 | |
| 101 | l4proto = __nf_ct_l4proto_find(l3num, l4num); |
| 102 | |
| 103 | /* This protocol is not supportted, skip. */ |
| 104 | if (l4proto->l4proto != l4num) |
| 105 | return -EOPNOTSUPP; |
| 106 | |
| 107 | if (matching) { |
| 108 | if (nlh->nlmsg_flags & NLM_F_REPLACE) { |
| 109 | /* You cannot replace one timeout policy by another of |
| 110 | * different kind, sorry. |
| 111 | */ |
| 112 | if (matching->l3num != l3num || |
| 113 | matching->l4num != l4num) |
| 114 | return -EINVAL; |
| 115 | |
| 116 | ret = ctnl_timeout_parse_policy(matching, l4proto, |
| 117 | cda[CTA_TIMEOUT_DATA]); |
| 118 | return ret; |
| 119 | } |
| 120 | return -EBUSY; |
| 121 | } |
| 122 | |
| 123 | timeout = kzalloc(sizeof(struct ctnl_timeout) + |
| 124 | l4proto->ctnl_timeout.obj_size, GFP_KERNEL); |
| 125 | if (timeout == NULL) |
| 126 | return -ENOMEM; |
| 127 | |
| 128 | ret = ctnl_timeout_parse_policy(timeout, l4proto, |
| 129 | cda[CTA_TIMEOUT_DATA]); |
| 130 | if (ret < 0) |
| 131 | goto err; |
| 132 | |
| 133 | strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME])); |
| 134 | timeout->l3num = l3num; |
| 135 | timeout->l4num = l4num; |
| 136 | atomic_set(&timeout->refcnt, 1); |
| 137 | list_add_tail_rcu(&timeout->head, &cttimeout_list); |
| 138 | |
| 139 | return 0; |
| 140 | err: |
| 141 | kfree(timeout); |
| 142 | return ret; |
| 143 | } |
| 144 | |
| 145 | static int |
| 146 | ctnl_timeout_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type, |
| 147 | int event, struct ctnl_timeout *timeout) |
| 148 | { |
| 149 | struct nlmsghdr *nlh; |
| 150 | struct nfgenmsg *nfmsg; |
| 151 | unsigned int flags = pid ? NLM_F_MULTI : 0; |
| 152 | struct nf_conntrack_l4proto *l4proto; |
| 153 | |
| 154 | event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8; |
| 155 | nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags); |
| 156 | if (nlh == NULL) |
| 157 | goto nlmsg_failure; |
| 158 | |
| 159 | nfmsg = nlmsg_data(nlh); |
| 160 | nfmsg->nfgen_family = AF_UNSPEC; |
| 161 | nfmsg->version = NFNETLINK_V0; |
| 162 | nfmsg->res_id = 0; |
| 163 | |
| 164 | NLA_PUT_STRING(skb, CTA_TIMEOUT_NAME, timeout->name); |
| 165 | NLA_PUT_BE16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)); |
| 166 | NLA_PUT_U8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4num); |
| 167 | NLA_PUT_BE32(skb, CTA_TIMEOUT_USE, |
| 168 | htonl(atomic_read(&timeout->refcnt))); |
| 169 | |
| 170 | l4proto = __nf_ct_l4proto_find(timeout->l3num, timeout->l4num); |
| 171 | |
| 172 | /* If the timeout object does not match the layer 4 protocol tracker, |
| 173 | * then skip dumping the data part since we don't know how to |
| 174 | * interpret it. This may happen for UPDlite, SCTP and DCCP since |
| 175 | * you can unload the module. |
| 176 | */ |
| 177 | if (timeout->l4num != l4proto->l4proto) |
| 178 | goto out; |
| 179 | |
| 180 | if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) { |
| 181 | struct nlattr *nest_parms; |
| 182 | int ret; |
| 183 | |
| 184 | nest_parms = nla_nest_start(skb, |
| 185 | CTA_TIMEOUT_DATA | NLA_F_NESTED); |
| 186 | if (!nest_parms) |
| 187 | goto nla_put_failure; |
| 188 | |
| 189 | ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data); |
| 190 | if (ret < 0) |
| 191 | goto nla_put_failure; |
| 192 | |
| 193 | nla_nest_end(skb, nest_parms); |
| 194 | } |
| 195 | out: |
| 196 | nlmsg_end(skb, nlh); |
| 197 | return skb->len; |
| 198 | |
| 199 | nlmsg_failure: |
| 200 | nla_put_failure: |
| 201 | nlmsg_cancel(skb, nlh); |
| 202 | return -1; |
| 203 | } |
| 204 | |
| 205 | static int |
| 206 | ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb) |
| 207 | { |
| 208 | struct ctnl_timeout *cur, *last; |
| 209 | |
| 210 | if (cb->args[2]) |
| 211 | return 0; |
| 212 | |
| 213 | last = (struct ctnl_timeout *)cb->args[1]; |
| 214 | if (cb->args[1]) |
| 215 | cb->args[1] = 0; |
| 216 | |
| 217 | rcu_read_lock(); |
| 218 | list_for_each_entry_rcu(cur, &cttimeout_list, head) { |
| 219 | if (last && cur != last) |
| 220 | continue; |
| 221 | |
| 222 | if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).pid, |
| 223 | cb->nlh->nlmsg_seq, |
| 224 | NFNL_MSG_TYPE(cb->nlh->nlmsg_type), |
| 225 | IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) { |
| 226 | cb->args[1] = (unsigned long)cur; |
| 227 | break; |
| 228 | } |
| 229 | } |
| 230 | if (!cb->args[1]) |
| 231 | cb->args[2] = 1; |
| 232 | rcu_read_unlock(); |
| 233 | return skb->len; |
| 234 | } |
| 235 | |
| 236 | static int |
| 237 | cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb, |
| 238 | const struct nlmsghdr *nlh, |
| 239 | const struct nlattr * const cda[]) |
| 240 | { |
| 241 | int ret = -ENOENT; |
| 242 | char *name; |
| 243 | struct ctnl_timeout *cur; |
| 244 | |
| 245 | if (nlh->nlmsg_flags & NLM_F_DUMP) { |
| 246 | struct netlink_dump_control c = { |
| 247 | .dump = ctnl_timeout_dump, |
| 248 | }; |
| 249 | return netlink_dump_start(ctnl, skb, nlh, &c); |
| 250 | } |
| 251 | |
| 252 | if (!cda[CTA_TIMEOUT_NAME]) |
| 253 | return -EINVAL; |
| 254 | name = nla_data(cda[CTA_TIMEOUT_NAME]); |
| 255 | |
| 256 | list_for_each_entry(cur, &cttimeout_list, head) { |
| 257 | struct sk_buff *skb2; |
| 258 | |
| 259 | if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) |
| 260 | continue; |
| 261 | |
| 262 | skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); |
| 263 | if (skb2 == NULL) { |
| 264 | ret = -ENOMEM; |
| 265 | break; |
| 266 | } |
| 267 | |
| 268 | ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).pid, |
| 269 | nlh->nlmsg_seq, |
| 270 | NFNL_MSG_TYPE(nlh->nlmsg_type), |
| 271 | IPCTNL_MSG_TIMEOUT_NEW, cur); |
| 272 | if (ret <= 0) { |
| 273 | kfree_skb(skb2); |
| 274 | break; |
| 275 | } |
| 276 | ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).pid, |
| 277 | MSG_DONTWAIT); |
| 278 | if (ret > 0) |
| 279 | ret = 0; |
| 280 | |
| 281 | /* this avoids a loop in nfnetlink. */ |
| 282 | return ret == -EAGAIN ? -ENOBUFS : ret; |
| 283 | } |
| 284 | return ret; |
| 285 | } |
| 286 | |
| 287 | /* try to delete object, fail if it is still in use. */ |
| 288 | static int ctnl_timeout_try_del(struct ctnl_timeout *timeout) |
| 289 | { |
| 290 | int ret = 0; |
| 291 | |
| 292 | /* we want to avoid races with nf_ct_timeout_find_get. */ |
| 293 | if (atomic_dec_and_test(&timeout->refcnt)) { |
| 294 | /* We are protected by nfnl mutex. */ |
| 295 | list_del_rcu(&timeout->head); |
| 296 | kfree_rcu(timeout, rcu_head); |
| 297 | } else { |
| 298 | /* still in use, restore reference counter. */ |
| 299 | atomic_inc(&timeout->refcnt); |
| 300 | ret = -EBUSY; |
| 301 | } |
| 302 | return ret; |
| 303 | } |
| 304 | |
| 305 | static int |
| 306 | cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb, |
| 307 | const struct nlmsghdr *nlh, |
| 308 | const struct nlattr * const cda[]) |
| 309 | { |
| 310 | char *name; |
| 311 | struct ctnl_timeout *cur; |
| 312 | int ret = -ENOENT; |
| 313 | |
| 314 | if (!cda[CTA_TIMEOUT_NAME]) { |
| 315 | list_for_each_entry(cur, &cttimeout_list, head) |
| 316 | ctnl_timeout_try_del(cur); |
| 317 | |
| 318 | return 0; |
| 319 | } |
| 320 | name = nla_data(cda[CTA_TIMEOUT_NAME]); |
| 321 | |
| 322 | list_for_each_entry(cur, &cttimeout_list, head) { |
| 323 | if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) |
| 324 | continue; |
| 325 | |
| 326 | ret = ctnl_timeout_try_del(cur); |
| 327 | if (ret < 0) |
| 328 | return ret; |
| 329 | |
| 330 | break; |
| 331 | } |
| 332 | return ret; |
| 333 | } |
| 334 | |
Pablo Neira Ayuso | 24de58f | 2012-02-29 02:19:19 +0100 | [diff] [blame^] | 335 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
| 336 | static struct ctnl_timeout *ctnl_timeout_find_get(const char *name) |
| 337 | { |
| 338 | struct ctnl_timeout *timeout, *matching = NULL; |
| 339 | |
| 340 | rcu_read_lock(); |
| 341 | list_for_each_entry_rcu(timeout, &cttimeout_list, head) { |
| 342 | if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0) |
| 343 | continue; |
| 344 | |
| 345 | if (!try_module_get(THIS_MODULE)) |
| 346 | goto err; |
| 347 | |
| 348 | if (!atomic_inc_not_zero(&timeout->refcnt)) { |
| 349 | module_put(THIS_MODULE); |
| 350 | goto err; |
| 351 | } |
| 352 | matching = timeout; |
| 353 | break; |
| 354 | } |
| 355 | err: |
| 356 | rcu_read_unlock(); |
| 357 | return matching; |
| 358 | } |
| 359 | |
| 360 | static void ctnl_timeout_put(struct ctnl_timeout *timeout) |
| 361 | { |
| 362 | atomic_dec(&timeout->refcnt); |
| 363 | module_put(THIS_MODULE); |
| 364 | } |
| 365 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
| 366 | |
Pablo Neira Ayuso | 5097846 | 2012-02-28 19:13:48 +0100 | [diff] [blame] | 367 | static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = { |
| 368 | [IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout, |
| 369 | .attr_count = CTA_TIMEOUT_MAX, |
| 370 | .policy = cttimeout_nla_policy }, |
| 371 | [IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout, |
| 372 | .attr_count = CTA_TIMEOUT_MAX, |
| 373 | .policy = cttimeout_nla_policy }, |
| 374 | [IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout, |
| 375 | .attr_count = CTA_TIMEOUT_MAX, |
| 376 | .policy = cttimeout_nla_policy }, |
| 377 | }; |
| 378 | |
| 379 | static const struct nfnetlink_subsystem cttimeout_subsys = { |
| 380 | .name = "conntrack_timeout", |
| 381 | .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT, |
| 382 | .cb_count = IPCTNL_MSG_TIMEOUT_MAX, |
| 383 | .cb = cttimeout_cb, |
| 384 | }; |
| 385 | |
| 386 | MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT); |
| 387 | |
| 388 | static int __init cttimeout_init(void) |
| 389 | { |
| 390 | int ret; |
| 391 | |
| 392 | ret = nfnetlink_subsys_register(&cttimeout_subsys); |
| 393 | if (ret < 0) { |
| 394 | pr_err("cttimeout_init: cannot register cttimeout with " |
| 395 | "nfnetlink.\n"); |
| 396 | goto err_out; |
| 397 | } |
Pablo Neira Ayuso | 24de58f | 2012-02-29 02:19:19 +0100 | [diff] [blame^] | 398 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
| 399 | RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get); |
| 400 | RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put); |
| 401 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
Pablo Neira Ayuso | 5097846 | 2012-02-28 19:13:48 +0100 | [diff] [blame] | 402 | return 0; |
| 403 | |
| 404 | err_out: |
| 405 | return ret; |
| 406 | } |
| 407 | |
| 408 | static void __exit cttimeout_exit(void) |
| 409 | { |
| 410 | struct ctnl_timeout *cur, *tmp; |
| 411 | |
| 412 | pr_info("cttimeout: unregistering from nfnetlink.\n"); |
| 413 | |
| 414 | nfnetlink_subsys_unregister(&cttimeout_subsys); |
| 415 | list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) { |
| 416 | list_del_rcu(&cur->head); |
| 417 | /* We are sure that our objects have no clients at this point, |
| 418 | * it's safe to release them all without checking refcnt. |
| 419 | */ |
| 420 | kfree_rcu(cur, rcu_head); |
| 421 | } |
Pablo Neira Ayuso | 24de58f | 2012-02-29 02:19:19 +0100 | [diff] [blame^] | 422 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
| 423 | RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL); |
| 424 | RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL); |
| 425 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
Pablo Neira Ayuso | 5097846 | 2012-02-28 19:13:48 +0100 | [diff] [blame] | 426 | } |
| 427 | |
| 428 | module_init(cttimeout_init); |
| 429 | module_exit(cttimeout_exit); |