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/atomic.h> 14#include <linux/netlink.h> 15#include <linux/rculist.h> 16#include <linux/slab.h> 17#include <linux/types.h> 18#include <linux/errno.h> 19#include <net/netlink.h> 20#include <net/sock.h> 21 22#include <linux/netfilter.h> 23#include <linux/netfilter/nfnetlink.h> 24#include <linux/netfilter/nfnetlink_acct.h> 25 26MODULE_LICENSE("GPL"); 27MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); 28MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure"); 29 30static LIST_HEAD(nfnl_acct_list); 31 32struct nf_acct { 33 atomic64_t pkts; 34 atomic64_t bytes; 35 unsigned long flags; 36 struct list_head head; 37 atomic_t refcnt; 38 char name[NFACCT_NAME_MAX]; 39 struct rcu_head rcu_head; 40 char data[0]; 41}; 42 43struct nfacct_filter { 44 u32 value; 45 u32 mask; 46}; 47 48#define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS | NFACCT_F_QUOTA_BYTES) 49#define NFACCT_OVERQUOTA_BIT 2 /* NFACCT_F_OVERQUOTA */ 50 51static int 52nfnl_acct_new(struct sock *nfnl, struct sk_buff *skb, 53 const struct nlmsghdr *nlh, const struct nlattr * const tb[]) 54{ 55 struct nf_acct *nfacct, *matching = NULL; 56 char *acct_name; 57 unsigned int size = 0; 58 u32 flags = 0; 59 60 if (!tb[NFACCT_NAME]) 61 return -EINVAL; 62 63 acct_name = nla_data(tb[NFACCT_NAME]); 64 if (strlen(acct_name) == 0) 65 return -EINVAL; 66 67 list_for_each_entry(nfacct, &nfnl_acct_list, head) { 68 if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0) 69 continue; 70 71 if (nlh->nlmsg_flags & NLM_F_EXCL) 72 return -EEXIST; 73 74 matching = nfacct; 75 break; 76 } 77 78 if (matching) { 79 if (nlh->nlmsg_flags & NLM_F_REPLACE) { 80 /* reset counters if you request a replacement. */ 81 atomic64_set(&matching->pkts, 0); 82 atomic64_set(&matching->bytes, 0); 83 smp_mb__before_atomic(); 84 /* reset overquota flag if quota is enabled. */ 85 if ((matching->flags & NFACCT_F_QUOTA)) 86 clear_bit(NFACCT_OVERQUOTA_BIT, 87 &matching->flags); 88 return 0; 89 } 90 return -EBUSY; 91 } 92 93 if (tb[NFACCT_FLAGS]) { 94 flags = ntohl(nla_get_be32(tb[NFACCT_FLAGS])); 95 if (flags & ~NFACCT_F_QUOTA) 96 return -EOPNOTSUPP; 97 if ((flags & NFACCT_F_QUOTA) == NFACCT_F_QUOTA) 98 return -EINVAL; 99 if (flags & NFACCT_F_OVERQUOTA) 100 return -EINVAL; 101 102 size += sizeof(u64); 103 } 104 105 nfacct = kzalloc(sizeof(struct nf_acct) + size, GFP_KERNEL); 106 if (nfacct == NULL) 107 return -ENOMEM; 108 109 if (flags & NFACCT_F_QUOTA) { 110 u64 *quota = (u64 *)nfacct->data; 111 112 *quota = be64_to_cpu(nla_get_be64(tb[NFACCT_QUOTA])); 113 nfacct->flags = flags; 114 } 115 116 strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX); 117 118 if (tb[NFACCT_BYTES]) { 119 atomic64_set(&nfacct->bytes, 120 be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES]))); 121 } 122 if (tb[NFACCT_PKTS]) { 123 atomic64_set(&nfacct->pkts, 124 be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS]))); 125 } 126 atomic_set(&nfacct->refcnt, 1); 127 list_add_tail_rcu(&nfacct->head, &nfnl_acct_list); 128 return 0; 129} 130 131static int 132nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type, 133 int event, struct nf_acct *acct) 134{ 135 struct nlmsghdr *nlh; 136 struct nfgenmsg *nfmsg; 137 unsigned int flags = portid ? NLM_F_MULTI : 0; 138 u64 pkts, bytes; 139 u32 old_flags; 140 141 event |= NFNL_SUBSYS_ACCT << 8; 142 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags); 143 if (nlh == NULL) 144 goto nlmsg_failure; 145 146 nfmsg = nlmsg_data(nlh); 147 nfmsg->nfgen_family = AF_UNSPEC; 148 nfmsg->version = NFNETLINK_V0; 149 nfmsg->res_id = 0; 150 151 if (nla_put_string(skb, NFACCT_NAME, acct->name)) 152 goto nla_put_failure; 153 154 old_flags = acct->flags; 155 if (type == NFNL_MSG_ACCT_GET_CTRZERO) { 156 pkts = atomic64_xchg(&acct->pkts, 0); 157 bytes = atomic64_xchg(&acct->bytes, 0); 158 smp_mb__before_atomic(); 159 if (acct->flags & NFACCT_F_QUOTA) 160 clear_bit(NFACCT_OVERQUOTA_BIT, &acct->flags); 161 } else { 162 pkts = atomic64_read(&acct->pkts); 163 bytes = atomic64_read(&acct->bytes); 164 } 165 if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts)) || 166 nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes)) || 167 nla_put_be32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt)))) 168 goto nla_put_failure; 169 if (acct->flags & NFACCT_F_QUOTA) { 170 u64 *quota = (u64 *)acct->data; 171 172 if (nla_put_be32(skb, NFACCT_FLAGS, htonl(old_flags)) || 173 nla_put_be64(skb, NFACCT_QUOTA, cpu_to_be64(*quota))) 174 goto nla_put_failure; 175 } 176 nlmsg_end(skb, nlh); 177 return skb->len; 178 179nlmsg_failure: 180nla_put_failure: 181 nlmsg_cancel(skb, nlh); 182 return -1; 183} 184 185static int 186nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb) 187{ 188 struct nf_acct *cur, *last; 189 const struct nfacct_filter *filter = cb->data; 190 191 if (cb->args[2]) 192 return 0; 193 194 last = (struct nf_acct *)cb->args[1]; 195 if (cb->args[1]) 196 cb->args[1] = 0; 197 198 rcu_read_lock(); 199 list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { 200 if (last) { 201 if (cur != last) 202 continue; 203 204 last = NULL; 205 } 206 207 if (filter && (cur->flags & filter->mask) != filter->value) 208 continue; 209 210 if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid, 211 cb->nlh->nlmsg_seq, 212 NFNL_MSG_TYPE(cb->nlh->nlmsg_type), 213 NFNL_MSG_ACCT_NEW, cur) < 0) { 214 cb->args[1] = (unsigned long)cur; 215 break; 216 } 217 } 218 if (!cb->args[1]) 219 cb->args[2] = 1; 220 rcu_read_unlock(); 221 return skb->len; 222} 223 224static int nfnl_acct_done(struct netlink_callback *cb) 225{ 226 kfree(cb->data); 227 return 0; 228} 229 230static const struct nla_policy filter_policy[NFACCT_FILTER_MAX + 1] = { 231 [NFACCT_FILTER_MASK] = { .type = NLA_U32 }, 232 [NFACCT_FILTER_VALUE] = { .type = NLA_U32 }, 233}; 234 235static struct nfacct_filter * 236nfacct_filter_alloc(const struct nlattr * const attr) 237{ 238 struct nfacct_filter *filter; 239 struct nlattr *tb[NFACCT_FILTER_MAX + 1]; 240 int err; 241 242 err = nla_parse_nested(tb, NFACCT_FILTER_MAX, attr, filter_policy); 243 if (err < 0) 244 return ERR_PTR(err); 245 246 filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL); 247 if (!filter) 248 return ERR_PTR(-ENOMEM); 249 250 filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK])); 251 filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE])); 252 253 return filter; 254} 255 256static int 257nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb, 258 const struct nlmsghdr *nlh, const struct nlattr * const tb[]) 259{ 260 int ret = -ENOENT; 261 struct nf_acct *cur; 262 char *acct_name; 263 264 if (nlh->nlmsg_flags & NLM_F_DUMP) { 265 struct netlink_dump_control c = { 266 .dump = nfnl_acct_dump, 267 .done = nfnl_acct_done, 268 }; 269 270 if (tb[NFACCT_FILTER]) { 271 struct nfacct_filter *filter; 272 273 filter = nfacct_filter_alloc(tb[NFACCT_FILTER]); 274 if (IS_ERR(filter)) 275 return PTR_ERR(filter); 276 277 c.data = filter; 278 } 279 return netlink_dump_start(nfnl, skb, nlh, &c); 280 } 281 282 if (!tb[NFACCT_NAME]) 283 return -EINVAL; 284 acct_name = nla_data(tb[NFACCT_NAME]); 285 286 list_for_each_entry(cur, &nfnl_acct_list, head) { 287 struct sk_buff *skb2; 288 289 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) 290 continue; 291 292 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 293 if (skb2 == NULL) { 294 ret = -ENOMEM; 295 break; 296 } 297 298 ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid, 299 nlh->nlmsg_seq, 300 NFNL_MSG_TYPE(nlh->nlmsg_type), 301 NFNL_MSG_ACCT_NEW, cur); 302 if (ret <= 0) { 303 kfree_skb(skb2); 304 break; 305 } 306 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid, 307 MSG_DONTWAIT); 308 if (ret > 0) 309 ret = 0; 310 311 /* this avoids a loop in nfnetlink. */ 312 return ret == -EAGAIN ? -ENOBUFS : ret; 313 } 314 return ret; 315} 316 317/* try to delete object, fail if it is still in use. */ 318static int nfnl_acct_try_del(struct nf_acct *cur) 319{ 320 int ret = 0; 321 322 /* we want to avoid races with nfnl_acct_find_get. */ 323 if (atomic_dec_and_test(&cur->refcnt)) { 324 /* We are protected by nfnl mutex. */ 325 list_del_rcu(&cur->head); 326 kfree_rcu(cur, rcu_head); 327 } else { 328 /* still in use, restore reference counter. */ 329 atomic_inc(&cur->refcnt); 330 ret = -EBUSY; 331 } 332 return ret; 333} 334 335static int 336nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb, 337 const struct nlmsghdr *nlh, const struct nlattr * const tb[]) 338{ 339 char *acct_name; 340 struct nf_acct *cur; 341 int ret = -ENOENT; 342 343 if (!tb[NFACCT_NAME]) { 344 list_for_each_entry(cur, &nfnl_acct_list, head) 345 nfnl_acct_try_del(cur); 346 347 return 0; 348 } 349 acct_name = nla_data(tb[NFACCT_NAME]); 350 351 list_for_each_entry(cur, &nfnl_acct_list, head) { 352 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0) 353 continue; 354 355 ret = nfnl_acct_try_del(cur); 356 if (ret < 0) 357 return ret; 358 359 break; 360 } 361 return ret; 362} 363 364static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = { 365 [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 }, 366 [NFACCT_BYTES] = { .type = NLA_U64 }, 367 [NFACCT_PKTS] = { .type = NLA_U64 }, 368 [NFACCT_FLAGS] = { .type = NLA_U32 }, 369 [NFACCT_QUOTA] = { .type = NLA_U64 }, 370 [NFACCT_FILTER] = {.type = NLA_NESTED }, 371}; 372 373static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = { 374 [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new, 375 .attr_count = NFACCT_MAX, 376 .policy = nfnl_acct_policy }, 377 [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get, 378 .attr_count = NFACCT_MAX, 379 .policy = nfnl_acct_policy }, 380 [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get, 381 .attr_count = NFACCT_MAX, 382 .policy = nfnl_acct_policy }, 383 [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del, 384 .attr_count = NFACCT_MAX, 385 .policy = nfnl_acct_policy }, 386}; 387 388static const struct nfnetlink_subsystem nfnl_acct_subsys = { 389 .name = "acct", 390 .subsys_id = NFNL_SUBSYS_ACCT, 391 .cb_count = NFNL_MSG_ACCT_MAX, 392 .cb = nfnl_acct_cb, 393}; 394 395MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT); 396 397struct nf_acct *nfnl_acct_find_get(const char *acct_name) 398{ 399 struct nf_acct *cur, *acct = NULL; 400 401 rcu_read_lock(); 402 list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { 403 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) 404 continue; 405 406 if (!try_module_get(THIS_MODULE)) 407 goto err; 408 409 if (!atomic_inc_not_zero(&cur->refcnt)) { 410 module_put(THIS_MODULE); 411 goto err; 412 } 413 414 acct = cur; 415 break; 416 } 417err: 418 rcu_read_unlock(); 419 return acct; 420} 421EXPORT_SYMBOL_GPL(nfnl_acct_find_get); 422 423void nfnl_acct_put(struct nf_acct *acct) 424{ 425 atomic_dec(&acct->refcnt); 426 module_put(THIS_MODULE); 427} 428EXPORT_SYMBOL_GPL(nfnl_acct_put); 429 430void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct) 431{ 432 atomic64_inc(&nfacct->pkts); 433 atomic64_add(skb->len, &nfacct->bytes); 434} 435EXPORT_SYMBOL_GPL(nfnl_acct_update); 436 437static void nfnl_overquota_report(struct nf_acct *nfacct) 438{ 439 int ret; 440 struct sk_buff *skb; 441 442 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); 443 if (skb == NULL) 444 return; 445 446 ret = nfnl_acct_fill_info(skb, 0, 0, NFNL_MSG_ACCT_OVERQUOTA, 0, 447 nfacct); 448 if (ret <= 0) { 449 kfree_skb(skb); 450 return; 451 } 452 netlink_broadcast(init_net.nfnl, skb, 0, NFNLGRP_ACCT_QUOTA, 453 GFP_ATOMIC); 454} 455 456int nfnl_acct_overquota(const struct sk_buff *skb, struct nf_acct *nfacct) 457{ 458 u64 now; 459 u64 *quota; 460 int ret = NFACCT_UNDERQUOTA; 461 462 /* no place here if we don't have a quota */ 463 if (!(nfacct->flags & NFACCT_F_QUOTA)) 464 return NFACCT_NO_QUOTA; 465 466 quota = (u64 *)nfacct->data; 467 now = (nfacct->flags & NFACCT_F_QUOTA_PKTS) ? 468 atomic64_read(&nfacct->pkts) : atomic64_read(&nfacct->bytes); 469 470 ret = now > *quota; 471 472 if (now >= *quota && 473 !test_and_set_bit(NFACCT_OVERQUOTA_BIT, &nfacct->flags)) { 474 nfnl_overquota_report(nfacct); 475 } 476 477 return ret; 478} 479EXPORT_SYMBOL_GPL(nfnl_acct_overquota); 480 481static int __init nfnl_acct_init(void) 482{ 483 int ret; 484 485 pr_info("nfnl_acct: registering with nfnetlink.\n"); 486 ret = nfnetlink_subsys_register(&nfnl_acct_subsys); 487 if (ret < 0) { 488 pr_err("nfnl_acct_init: cannot register with nfnetlink.\n"); 489 goto err_out; 490 } 491 return 0; 492err_out: 493 return ret; 494} 495 496static void __exit nfnl_acct_exit(void) 497{ 498 struct nf_acct *cur, *tmp; 499 500 pr_info("nfnl_acct: unregistering from nfnetlink.\n"); 501 nfnetlink_subsys_unregister(&nfnl_acct_subsys); 502 503 list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) { 504 list_del_rcu(&cur->head); 505 /* We are sure that our objects have no clients at this point, 506 * it's safe to release them all without checking refcnt. */ 507 kfree_rcu(cur, rcu_head); 508 } 509} 510 511module_init(nfnl_acct_init); 512module_exit(nfnl_acct_exit); 513