Pablo Neira Ayuso | 9413902 | 2011-12-23 14:19:50 +0100 | [diff] [blame] | 1 | /* |
| 2 | * (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org> |
| 3 | * (C) 2011 Intra2net AG <http://www.intra2net.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/skbuff.h> |
| 13 | #include <linux/netlink.h> |
| 14 | #include <linux/rculist.h> |
| 15 | #include <linux/slab.h> |
| 16 | #include <linux/types.h> |
| 17 | #include <linux/errno.h> |
| 18 | #include <net/netlink.h> |
| 19 | #include <net/sock.h> |
| 20 | #include <asm/atomic.h> |
| 21 | |
| 22 | #include <linux/netfilter.h> |
| 23 | #include <linux/netfilter/nfnetlink.h> |
| 24 | #include <linux/netfilter/nfnetlink_acct.h> |
| 25 | |
| 26 | MODULE_LICENSE("GPL"); |
| 27 | MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); |
| 28 | MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure"); |
| 29 | |
| 30 | static LIST_HEAD(nfnl_acct_list); |
| 31 | |
| 32 | struct nf_acct { |
| 33 | atomic64_t pkts; |
| 34 | atomic64_t bytes; |
| 35 | struct list_head head; |
| 36 | atomic_t refcnt; |
| 37 | char name[NFACCT_NAME_MAX]; |
| 38 | struct rcu_head rcu_head; |
| 39 | }; |
| 40 | |
| 41 | static int |
| 42 | nfnl_acct_new(struct sock *nfnl, struct sk_buff *skb, |
| 43 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) |
| 44 | { |
| 45 | struct nf_acct *nfacct, *matching = NULL; |
| 46 | char *acct_name; |
| 47 | |
| 48 | if (!tb[NFACCT_NAME]) |
| 49 | return -EINVAL; |
| 50 | |
| 51 | acct_name = nla_data(tb[NFACCT_NAME]); |
| 52 | |
| 53 | list_for_each_entry(nfacct, &nfnl_acct_list, head) { |
| 54 | if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0) |
| 55 | continue; |
| 56 | |
| 57 | if (nlh->nlmsg_flags & NLM_F_EXCL) |
| 58 | return -EEXIST; |
| 59 | |
| 60 | matching = nfacct; |
| 61 | break; |
| 62 | } |
| 63 | |
| 64 | if (matching) { |
| 65 | if (nlh->nlmsg_flags & NLM_F_REPLACE) { |
| 66 | /* reset counters if you request a replacement. */ |
| 67 | atomic64_set(&matching->pkts, 0); |
| 68 | atomic64_set(&matching->bytes, 0); |
| 69 | return 0; |
| 70 | } |
| 71 | return -EBUSY; |
| 72 | } |
| 73 | |
| 74 | nfacct = kzalloc(sizeof(struct nf_acct), GFP_KERNEL); |
| 75 | if (nfacct == NULL) |
| 76 | return -ENOMEM; |
| 77 | |
| 78 | strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX); |
| 79 | |
| 80 | if (tb[NFACCT_BYTES]) { |
| 81 | atomic64_set(&nfacct->bytes, |
| 82 | be64_to_cpu(nla_get_u64(tb[NFACCT_BYTES]))); |
| 83 | } |
| 84 | if (tb[NFACCT_PKTS]) { |
| 85 | atomic64_set(&nfacct->pkts, |
| 86 | be64_to_cpu(nla_get_u64(tb[NFACCT_PKTS]))); |
| 87 | } |
| 88 | atomic_set(&nfacct->refcnt, 1); |
| 89 | list_add_tail_rcu(&nfacct->head, &nfnl_acct_list); |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | static int |
| 94 | nfnl_acct_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type, |
| 95 | int event, struct nf_acct *acct) |
| 96 | { |
| 97 | struct nlmsghdr *nlh; |
| 98 | struct nfgenmsg *nfmsg; |
| 99 | unsigned int flags = pid ? NLM_F_MULTI : 0; |
| 100 | u64 pkts, bytes; |
| 101 | |
| 102 | event |= NFNL_SUBSYS_ACCT << 8; |
| 103 | nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags); |
| 104 | if (nlh == NULL) |
| 105 | goto nlmsg_failure; |
| 106 | |
| 107 | nfmsg = nlmsg_data(nlh); |
| 108 | nfmsg->nfgen_family = AF_UNSPEC; |
| 109 | nfmsg->version = NFNETLINK_V0; |
| 110 | nfmsg->res_id = 0; |
| 111 | |
| 112 | NLA_PUT_STRING(skb, NFACCT_NAME, acct->name); |
| 113 | |
| 114 | if (type == NFNL_MSG_ACCT_GET_CTRZERO) { |
| 115 | pkts = atomic64_xchg(&acct->pkts, 0); |
| 116 | bytes = atomic64_xchg(&acct->bytes, 0); |
| 117 | } else { |
| 118 | pkts = atomic64_read(&acct->pkts); |
| 119 | bytes = atomic64_read(&acct->bytes); |
| 120 | } |
| 121 | NLA_PUT_BE64(skb, NFACCT_PKTS, cpu_to_be64(pkts)); |
| 122 | NLA_PUT_BE64(skb, NFACCT_BYTES, cpu_to_be64(bytes)); |
| 123 | NLA_PUT_BE32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt))); |
| 124 | |
| 125 | nlmsg_end(skb, nlh); |
| 126 | return skb->len; |
| 127 | |
| 128 | nlmsg_failure: |
| 129 | nla_put_failure: |
| 130 | nlmsg_cancel(skb, nlh); |
| 131 | return -1; |
| 132 | } |
| 133 | |
| 134 | static int |
| 135 | nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb) |
| 136 | { |
| 137 | struct nf_acct *cur, *last; |
| 138 | |
| 139 | if (cb->args[2]) |
| 140 | return 0; |
| 141 | |
| 142 | last = (struct nf_acct *)cb->args[1]; |
| 143 | if (cb->args[1]) |
| 144 | cb->args[1] = 0; |
| 145 | |
| 146 | rcu_read_lock(); |
| 147 | list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { |
| 148 | if (last && cur != last) |
| 149 | continue; |
| 150 | |
| 151 | if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).pid, |
| 152 | cb->nlh->nlmsg_seq, |
| 153 | NFNL_MSG_TYPE(cb->nlh->nlmsg_type), |
| 154 | NFNL_MSG_ACCT_NEW, cur) < 0) { |
| 155 | cb->args[1] = (unsigned long)cur; |
| 156 | break; |
| 157 | } |
| 158 | } |
| 159 | if (!cb->args[1]) |
| 160 | cb->args[2] = 1; |
| 161 | rcu_read_unlock(); |
| 162 | return skb->len; |
| 163 | } |
| 164 | |
| 165 | static int |
| 166 | nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb, |
| 167 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) |
| 168 | { |
Pablo Neira Ayuso | 3ab0b24 | 2011-12-30 20:32:26 +0100 | [diff] [blame] | 169 | int ret = -ENOENT; |
Pablo Neira Ayuso | 9413902 | 2011-12-23 14:19:50 +0100 | [diff] [blame] | 170 | struct nf_acct *cur; |
| 171 | char *acct_name; |
| 172 | |
| 173 | if (nlh->nlmsg_flags & NLM_F_DUMP) { |
| 174 | return netlink_dump_start(nfnl, skb, nlh, nfnl_acct_dump, |
| 175 | NULL, 0); |
| 176 | } |
| 177 | |
| 178 | if (!tb[NFACCT_NAME]) |
| 179 | return -EINVAL; |
| 180 | acct_name = nla_data(tb[NFACCT_NAME]); |
| 181 | |
| 182 | list_for_each_entry(cur, &nfnl_acct_list, head) { |
| 183 | struct sk_buff *skb2; |
| 184 | |
| 185 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) |
| 186 | continue; |
| 187 | |
| 188 | skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); |
Pablo Neira Ayuso | 3ab0b24 | 2011-12-30 20:32:26 +0100 | [diff] [blame] | 189 | if (skb2 == NULL) { |
| 190 | ret = -ENOMEM; |
Pablo Neira Ayuso | 9413902 | 2011-12-23 14:19:50 +0100 | [diff] [blame] | 191 | break; |
Pablo Neira Ayuso | 3ab0b24 | 2011-12-30 20:32:26 +0100 | [diff] [blame] | 192 | } |
Pablo Neira Ayuso | 9413902 | 2011-12-23 14:19:50 +0100 | [diff] [blame] | 193 | |
| 194 | ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).pid, |
| 195 | nlh->nlmsg_seq, |
| 196 | NFNL_MSG_TYPE(nlh->nlmsg_type), |
| 197 | NFNL_MSG_ACCT_NEW, cur); |
Pablo Neira Ayuso | 3ab0b24 | 2011-12-30 20:32:26 +0100 | [diff] [blame] | 198 | if (ret <= 0) { |
Pablo Neira Ayuso | 9413902 | 2011-12-23 14:19:50 +0100 | [diff] [blame] | 199 | kfree_skb(skb2); |
Pablo Neira Ayuso | 3ab0b24 | 2011-12-30 20:32:26 +0100 | [diff] [blame] | 200 | break; |
| 201 | } |
| 202 | ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).pid, |
| 203 | MSG_DONTWAIT); |
| 204 | if (ret > 0) |
| 205 | ret = 0; |
Pablo Neira Ayuso | 9413902 | 2011-12-23 14:19:50 +0100 | [diff] [blame] | 206 | |
Pablo Neira Ayuso | 3ab0b24 | 2011-12-30 20:32:26 +0100 | [diff] [blame] | 207 | /* this avoids a loop in nfnetlink. */ |
| 208 | return ret == -EAGAIN ? -ENOBUFS : ret; |
Pablo Neira Ayuso | 9413902 | 2011-12-23 14:19:50 +0100 | [diff] [blame] | 209 | } |
| 210 | return ret; |
| 211 | } |
| 212 | |
| 213 | /* try to delete object, fail if it is still in use. */ |
| 214 | static int nfnl_acct_try_del(struct nf_acct *cur) |
| 215 | { |
| 216 | int ret = 0; |
| 217 | |
| 218 | /* we want to avoid races with nfnl_acct_find_get. */ |
| 219 | if (atomic_dec_and_test(&cur->refcnt)) { |
| 220 | /* We are protected by nfnl mutex. */ |
| 221 | list_del_rcu(&cur->head); |
| 222 | kfree_rcu(cur, rcu_head); |
| 223 | } else { |
| 224 | /* still in use, restore reference counter. */ |
| 225 | atomic_inc(&cur->refcnt); |
| 226 | ret = -EBUSY; |
| 227 | } |
| 228 | return ret; |
| 229 | } |
| 230 | |
| 231 | static int |
| 232 | nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb, |
| 233 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) |
| 234 | { |
| 235 | char *acct_name; |
| 236 | struct nf_acct *cur; |
| 237 | int ret = -ENOENT; |
| 238 | |
| 239 | if (!tb[NFACCT_NAME]) { |
| 240 | list_for_each_entry(cur, &nfnl_acct_list, head) |
| 241 | nfnl_acct_try_del(cur); |
| 242 | |
| 243 | return 0; |
| 244 | } |
| 245 | acct_name = nla_data(tb[NFACCT_NAME]); |
| 246 | |
| 247 | list_for_each_entry(cur, &nfnl_acct_list, head) { |
| 248 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0) |
| 249 | continue; |
| 250 | |
| 251 | ret = nfnl_acct_try_del(cur); |
| 252 | if (ret < 0) |
| 253 | return ret; |
| 254 | |
| 255 | break; |
| 256 | } |
| 257 | return ret; |
| 258 | } |
| 259 | |
| 260 | static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = { |
| 261 | [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 }, |
| 262 | [NFACCT_BYTES] = { .type = NLA_U64 }, |
| 263 | [NFACCT_PKTS] = { .type = NLA_U64 }, |
| 264 | }; |
| 265 | |
| 266 | static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = { |
| 267 | [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new, |
| 268 | .attr_count = NFACCT_MAX, |
| 269 | .policy = nfnl_acct_policy }, |
| 270 | [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get, |
| 271 | .attr_count = NFACCT_MAX, |
| 272 | .policy = nfnl_acct_policy }, |
| 273 | [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get, |
| 274 | .attr_count = NFACCT_MAX, |
| 275 | .policy = nfnl_acct_policy }, |
| 276 | [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del, |
| 277 | .attr_count = NFACCT_MAX, |
| 278 | .policy = nfnl_acct_policy }, |
| 279 | }; |
| 280 | |
| 281 | static const struct nfnetlink_subsystem nfnl_acct_subsys = { |
| 282 | .name = "acct", |
| 283 | .subsys_id = NFNL_SUBSYS_ACCT, |
| 284 | .cb_count = NFNL_MSG_ACCT_MAX, |
| 285 | .cb = nfnl_acct_cb, |
| 286 | }; |
| 287 | |
| 288 | MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT); |
| 289 | |
| 290 | struct nf_acct *nfnl_acct_find_get(const char *acct_name) |
| 291 | { |
| 292 | struct nf_acct *cur, *acct = NULL; |
| 293 | |
| 294 | rcu_read_lock(); |
| 295 | list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { |
| 296 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) |
| 297 | continue; |
| 298 | |
| 299 | if (!try_module_get(THIS_MODULE)) |
| 300 | goto err; |
| 301 | |
| 302 | if (!atomic_inc_not_zero(&cur->refcnt)) { |
| 303 | module_put(THIS_MODULE); |
| 304 | goto err; |
| 305 | } |
| 306 | |
| 307 | acct = cur; |
| 308 | break; |
| 309 | } |
| 310 | err: |
| 311 | rcu_read_unlock(); |
| 312 | return acct; |
| 313 | } |
| 314 | EXPORT_SYMBOL_GPL(nfnl_acct_find_get); |
| 315 | |
| 316 | void nfnl_acct_put(struct nf_acct *acct) |
| 317 | { |
| 318 | atomic_dec(&acct->refcnt); |
| 319 | module_put(THIS_MODULE); |
| 320 | } |
| 321 | EXPORT_SYMBOL_GPL(nfnl_acct_put); |
| 322 | |
| 323 | void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct) |
| 324 | { |
| 325 | atomic64_inc(&nfacct->pkts); |
| 326 | atomic64_add(skb->len, &nfacct->bytes); |
| 327 | } |
| 328 | EXPORT_SYMBOL_GPL(nfnl_acct_update); |
| 329 | |
| 330 | static int __init nfnl_acct_init(void) |
| 331 | { |
| 332 | int ret; |
| 333 | |
| 334 | pr_info("nfnl_acct: registering with nfnetlink.\n"); |
| 335 | ret = nfnetlink_subsys_register(&nfnl_acct_subsys); |
| 336 | if (ret < 0) { |
| 337 | pr_err("nfnl_acct_init: cannot register with nfnetlink.\n"); |
| 338 | goto err_out; |
| 339 | } |
| 340 | return 0; |
| 341 | err_out: |
| 342 | return ret; |
| 343 | } |
| 344 | |
| 345 | static void __exit nfnl_acct_exit(void) |
| 346 | { |
| 347 | struct nf_acct *cur, *tmp; |
| 348 | |
| 349 | pr_info("nfnl_acct: unregistering from nfnetlink.\n"); |
| 350 | nfnetlink_subsys_unregister(&nfnl_acct_subsys); |
| 351 | |
| 352 | list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) { |
| 353 | list_del_rcu(&cur->head); |
| 354 | /* We are sure that our objects have no clients at this point, |
| 355 | * it's safe to release them all without checking refcnt. */ |
| 356 | kfree_rcu(cur, rcu_head); |
| 357 | } |
| 358 | } |
| 359 | |
| 360 | module_init(nfnl_acct_init); |
| 361 | module_exit(nfnl_acct_exit); |