net/netfilter/nft_ct.c

   1 /*
   2  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/netlink.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/netfilter/nf_tables.h>
  17 #include <net/netfilter/nf_tables.h>
  18 #include <net/netfilter/nf_conntrack.h>
  19 #include <net/netfilter/nf_conntrack_acct.h>
  20 #include <net/netfilter/nf_conntrack_tuple.h>
  21 #include <net/netfilter/nf_conntrack_helper.h>
  22 #include <net/netfilter/nf_conntrack_ecache.h>
  23 #include <net/netfilter/nf_conntrack_labels.h>
  24
  25 struct nft_ct {
  26         enum nft_ct_keys        key:8;
  27         enum ip_conntrack_dir   dir:8;
  28         union {
  29                 enum nft_registers      dreg:8;
  30                 enum nft_registers      sreg:8;
  31         };
  32 };
  33
  34 static u64 nft_ct_get_eval_counter(const struct nf_conn_counter *c,
  35                                    enum nft_ct_keys k,
  36                                    enum ip_conntrack_dir d)
  37 {
  38         if (d < IP_CT_DIR_MAX)
  39                 return k == NFT_CT_BYTES ? atomic64_read(&c[d].bytes) :
  40                                            atomic64_read(&c[d].packets);
  41
  42         return nft_ct_get_eval_counter(c, k, IP_CT_DIR_ORIGINAL) +
  43                nft_ct_get_eval_counter(c, k, IP_CT_DIR_REPLY);
  44 }
  45
  46 static void nft_ct_get_eval(const struct nft_expr *expr,
  47                             struct nft_regs *regs,
  48                             const struct nft_pktinfo *pkt)
  49 {
  50         const struct nft_ct *priv = nft_expr_priv(expr);
  51         u32 *dest = &regs->data[priv->dreg];
  52         enum ip_conntrack_info ctinfo;
  53         const struct nf_conn *ct;
  54         const struct nf_conn_help *help;
  55         const struct nf_conntrack_tuple *tuple;
  56         const struct nf_conntrack_helper *helper;
  57         unsigned int state;
  58
  59         ct = nf_ct_get(pkt->skb, &ctinfo);
  60
  61         switch (priv->key) {
  62         case NFT_CT_STATE:
  63                 if (ct == NULL)
  64                         state = NF_CT_STATE_INVALID_BIT;
  65                 else if (nf_ct_is_untracked(ct))
  66                         state = NF_CT_STATE_UNTRACKED_BIT;
  67                 else
  68                         state = NF_CT_STATE_BIT(ctinfo);
  69                 *dest = state;
  70                 return;
  71         default:
  72                 break;
  73         }
  74
  75         if (ct == NULL)
  76                 goto err;
  77
  78         switch (priv->key) {
  79         case NFT_CT_DIRECTION:
  80                 *dest = CTINFO2DIR(ctinfo);
  81                 return;
  82         case NFT_CT_STATUS:
  83                 *dest = ct->status;
  84                 return;
  85 #ifdef CONFIG_NF_CONNTRACK_MARK
  86         case NFT_CT_MARK:
  87                 *dest = ct->mark;
  88                 return;
  89 #endif
  90 #ifdef CONFIG_NF_CONNTRACK_SECMARK
  91         case NFT_CT_SECMARK:
  92                 *dest = ct->secmark;
  93                 return;
  94 #endif
  95         case NFT_CT_EXPIRATION:
  96                 *dest = jiffies_to_msecs(nf_ct_expires(ct));
  97                 return;
  98         case NFT_CT_HELPER:
  99                 if (ct->master == NULL)
 100                         goto err;
 101                 help = nfct_help(ct->master);
 102                 if (help == NULL)
 103                         goto err;
 104                 helper = rcu_dereference(help->helper);
 105                 if (helper == NULL)
 106                         goto err;
 107                 strncpy((char *)dest, helper->name, NF_CT_HELPER_NAME_LEN);
 108                 return;
 109 #ifdef CONFIG_NF_CONNTRACK_LABELS
 110         case NFT_CT_LABELS: {
 111                 struct nf_conn_labels *labels = nf_ct_labels_find(ct);
 112                 unsigned int size;
 113
 114                 if (!labels) {
 115                         memset(dest, 0, NF_CT_LABELS_MAX_SIZE);
 116                         return;
 117                 }
 118
 119                 size = labels->words * sizeof(long);
 120                 memcpy(dest, labels->bits, size);
 121                 if (size < NF_CT_LABELS_MAX_SIZE)
 122                         memset(((char *) dest) + size, 0,
 123                                NF_CT_LABELS_MAX_SIZE - size);
 124                 return;
 125         }
 126 #endif
 127         case NFT_CT_BYTES: /* fallthrough */
 128         case NFT_CT_PKTS: {
 129                 const struct nf_conn_acct *acct = nf_conn_acct_find(ct);
 130                 u64 count = 0;
 131
 132                 if (acct)
 133                         count = nft_ct_get_eval_counter(acct->counter,
 134                                                         priv->key, priv->dir);
 135                 memcpy(dest, &count, sizeof(count));
 136                 return;
 137         }
 138         default:
 139                 break;
 140         }
 141
 142         tuple = &ct->tuplehash[priv->dir].tuple;
 143         switch (priv->key) {
 144         case NFT_CT_L3PROTOCOL:
 145                 *dest = nf_ct_l3num(ct);
 146                 return;
 147         case NFT_CT_SRC:
 148                 memcpy(dest, tuple->src.u3.all,
 149                        nf_ct_l3num(ct) == NFPROTO_IPV4 ? 4 : 16);
 150                 return;
 151         case NFT_CT_DST:
 152                 memcpy(dest, tuple->dst.u3.all,
 153                        nf_ct_l3num(ct) == NFPROTO_IPV4 ? 4 : 16);
 154                 return;
 155         case NFT_CT_PROTOCOL:
 156                 *dest = nf_ct_protonum(ct);
 157                 return;
 158         case NFT_CT_PROTO_SRC:
 159                 *dest = (__force __u16)tuple->src.u.all;
 160                 return;
 161         case NFT_CT_PROTO_DST:
 162                 *dest = (__force __u16)tuple->dst.u.all;
 163                 return;
 164         default:
 165                 break;
 166         }
 167         return;
 168 err:
 169         regs->verdict.code = NFT_BREAK;
 170 }
 171
 172 static void nft_ct_set_eval(const struct nft_expr *expr,
 173                             struct nft_regs *regs,
 174                             const struct nft_pktinfo *pkt)
 175 {
 176         const struct nft_ct *priv = nft_expr_priv(expr);
 177         struct sk_buff *skb = pkt->skb;
 178 #ifdef CONFIG_NF_CONNTRACK_MARK
 179         u32 value = regs->data[priv->sreg];
 180 #endif
 181         enum ip_conntrack_info ctinfo;
 182         struct nf_conn *ct;
 183
 184         ct = nf_ct_get(skb, &ctinfo);
 185         if (ct == NULL)
 186                 return;
 187
 188         switch (priv->key) {
 189 #ifdef CONFIG_NF_CONNTRACK_MARK
 190         case NFT_CT_MARK:
 191                 if (ct->mark != value) {
 192                         ct->mark = value;
 193                         nf_conntrack_event_cache(IPCT_MARK, ct);
 194                 }
 195                 break;
 196 #endif
 197 #ifdef CONFIG_NF_CONNTRACK_LABELS
 198         case NFT_CT_LABELS:
 199                 nf_connlabels_replace(ct,
 200                                       &regs->data[priv->sreg],
 201                                       &regs->data[priv->sreg],
 202                                       NF_CT_LABELS_MAX_SIZE / sizeof(u32));
 203                 break;
 204 #endif
 205         default:
 206                 break;
 207         }
 208 }
 209
 210 static const struct nla_policy nft_ct_policy[NFTA_CT_MAX + 1] = {
 211         [NFTA_CT_DREG]          = { .type = NLA_U32 },
 212         [NFTA_CT_KEY]           = { .type = NLA_U32 },
 213         [NFTA_CT_DIRECTION]     = { .type = NLA_U8 },
 214         [NFTA_CT_SREG]          = { .type = NLA_U32 },
 215 };
 216
 217 static int nft_ct_l3proto_try_module_get(uint8_t family)
 218 {
 219         int err;
 220
 221         if (family == NFPROTO_INET) {
 222                 err = nf_ct_l3proto_try_module_get(NFPROTO_IPV4);
 223                 if (err < 0)
 224                         goto err1;
 225                 err = nf_ct_l3proto_try_module_get(NFPROTO_IPV6);
 226                 if (err < 0)
 227                         goto err2;
 228         } else {
 229                 err = nf_ct_l3proto_try_module_get(family);
 230                 if (err < 0)
 231                         goto err1;
 232         }
 233         return 0;
 234
 235 err2:
 236         nf_ct_l3proto_module_put(NFPROTO_IPV4);
 237 err1:
 238         return err;
 239 }
 240
 241 static void nft_ct_l3proto_module_put(uint8_t family)
 242 {
 243         if (family == NFPROTO_INET) {
 244                 nf_ct_l3proto_module_put(NFPROTO_IPV4);
 245                 nf_ct_l3proto_module_put(NFPROTO_IPV6);
 246         } else
 247                 nf_ct_l3proto_module_put(family);
 248 }
 249
 250 static int nft_ct_get_init(const struct nft_ctx *ctx,
 251                            const struct nft_expr *expr,
 252                            const struct nlattr * const tb[])
 253 {
 254         struct nft_ct *priv = nft_expr_priv(expr);
 255         unsigned int len;
 256         int err;
 257
 258         priv->key = ntohl(nla_get_be32(tb[NFTA_CT_KEY]));
 259         switch (priv->key) {
 260         case NFT_CT_DIRECTION:
 261                 if (tb[NFTA_CT_DIRECTION] != NULL)
 262                         return -EINVAL;
 263                 len = sizeof(u8);
 264                 break;
 265         case NFT_CT_STATE:
 266         case NFT_CT_STATUS:
 267 #ifdef CONFIG_NF_CONNTRACK_MARK
 268         case NFT_CT_MARK:
 269 #endif
 270 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 271         case NFT_CT_SECMARK:
 272 #endif
 273         case NFT_CT_EXPIRATION:
 274                 if (tb[NFTA_CT_DIRECTION] != NULL)
 275                         return -EINVAL;
 276                 len = sizeof(u32);
 277                 break;
 278 #ifdef CONFIG_NF_CONNTRACK_LABELS
 279         case NFT_CT_LABELS:
 280                 if (tb[NFTA_CT_DIRECTION] != NULL)
 281                         return -EINVAL;
 282                 len = NF_CT_LABELS_MAX_SIZE;
 283                 break;
 284 #endif
 285         case NFT_CT_HELPER:
 286                 if (tb[NFTA_CT_DIRECTION] != NULL)
 287                         return -EINVAL;
 288                 len = NF_CT_HELPER_NAME_LEN;
 289                 break;
 290
 291         case NFT_CT_L3PROTOCOL:
 292         case NFT_CT_PROTOCOL:
 293                 if (tb[NFTA_CT_DIRECTION] == NULL)
 294                         return -EINVAL;
 295                 len = sizeof(u8);
 296                 break;
 297         case NFT_CT_SRC:
 298         case NFT_CT_DST:
 299                 if (tb[NFTA_CT_DIRECTION] == NULL)
 300                         return -EINVAL;
 301
 302                 switch (ctx->afi->family) {
 303                 case NFPROTO_IPV4:
 304                         len = FIELD_SIZEOF(struct nf_conntrack_tuple,
 305                                            src.u3.ip);
 306                         break;
 307                 case NFPROTO_IPV6:
 308                 case NFPROTO_INET:
 309                         len = FIELD_SIZEOF(struct nf_conntrack_tuple,
 310                                            src.u3.ip6);
 311                         break;
 312                 default:
 313                         return -EAFNOSUPPORT;
 314                 }
 315                 break;
 316         case NFT_CT_PROTO_SRC:
 317         case NFT_CT_PROTO_DST:
 318                 if (tb[NFTA_CT_DIRECTION] == NULL)
 319                         return -EINVAL;
 320                 len = FIELD_SIZEOF(struct nf_conntrack_tuple, src.u.all);
 321                 break;
 322         case NFT_CT_BYTES:
 323         case NFT_CT_PKTS:
 324                 /* no direction? return sum of original + reply */
 325                 if (tb[NFTA_CT_DIRECTION] == NULL)
 326                         priv->dir = IP_CT_DIR_MAX;
 327                 len = sizeof(u64);
 328                 break;
 329         default:
 330                 return -EOPNOTSUPP;
 331         }
 332
 333         if (tb[NFTA_CT_DIRECTION] != NULL) {
 334                 priv->dir = nla_get_u8(tb[NFTA_CT_DIRECTION]);
 335                 switch (priv->dir) {
 336                 case IP_CT_DIR_ORIGINAL:
 337                 case IP_CT_DIR_REPLY:
 338                         break;
 339                 default:
 340                         return -EINVAL;
 341                 }
 342         }
 343
 344         priv->dreg = nft_parse_register(tb[NFTA_CT_DREG]);
 345         err = nft_validate_register_store(ctx, priv->dreg, NULL,
 346                                           NFT_DATA_VALUE, len);
 347         if (err < 0)
 348                 return err;
 349
 350         err = nft_ct_l3proto_try_module_get(ctx->afi->family);
 351         if (err < 0)
 352                 return err;
 353
 354         return 0;
 355 }
 356
 357 static int nft_ct_set_init(const struct nft_ctx *ctx,
 358                            const struct nft_expr *expr,
 359                            const struct nlattr * const tb[])
 360 {
 361         struct nft_ct *priv = nft_expr_priv(expr);
 362         unsigned int len;
 363         int err;
 364
 365         priv->key = ntohl(nla_get_be32(tb[NFTA_CT_KEY]));
 366         switch (priv->key) {
 367 #ifdef CONFIG_NF_CONNTRACK_MARK
 368         case NFT_CT_MARK:
 369                 len = FIELD_SIZEOF(struct nf_conn, mark);
 370                 break;
 371 #endif
 372 #ifdef CONFIG_NF_CONNTRACK_LABELS
 373         case NFT_CT_LABELS:
 374                 if (tb[NFTA_CT_DIRECTION])
 375                         return -EINVAL;
 376                 len = NF_CT_LABELS_MAX_SIZE;
 377                 err = nf_connlabels_get(ctx->net, (len * BITS_PER_BYTE) - 1);
 378                 if (err)
 379                         return err;
 380                 break;
 381 #endif
 382         default:
 383                 return -EOPNOTSUPP;
 384         }
 385
 386         priv->sreg = nft_parse_register(tb[NFTA_CT_SREG]);
 387         err = nft_validate_register_load(priv->sreg, len);
 388         if (err < 0)
 389                 return err;
 390
 391         err = nft_ct_l3proto_try_module_get(ctx->afi->family);
 392         if (err < 0)
 393                 return err;
 394
 395         return 0;
 396 }
 397
 398 static void nft_ct_destroy(const struct nft_ctx *ctx,
 399                            const struct nft_expr *expr)
 400 {
 401         struct nft_ct *priv = nft_expr_priv(expr);
 402
 403         switch (priv->key) {
 404 #ifdef CONFIG_NF_CONNTRACK_LABELS
 405         case NFT_CT_LABELS:
 406                 nf_connlabels_put(ctx->net);
 407                 break;
 408 #endif
 409         default:
 410                 break;
 411         }
 412
 413         nft_ct_l3proto_module_put(ctx->afi->family);
 414 }
 415
 416 static int nft_ct_get_dump(struct sk_buff *skb, const struct nft_expr *expr)
 417 {
 418         const struct nft_ct *priv = nft_expr_priv(expr);
 419
 420         if (nft_dump_register(skb, NFTA_CT_DREG, priv->dreg))
 421                 goto nla_put_failure;
 422         if (nla_put_be32(skb, NFTA_CT_KEY, htonl(priv->key)))
 423                 goto nla_put_failure;
 424
 425         switch (priv->key) {
 426         case NFT_CT_L3PROTOCOL:
 427         case NFT_CT_PROTOCOL:
 428         case NFT_CT_SRC:
 429         case NFT_CT_DST:
 430         case NFT_CT_PROTO_SRC:
 431         case NFT_CT_PROTO_DST:
 432                 if (nla_put_u8(skb, NFTA_CT_DIRECTION, priv->dir))
 433                         goto nla_put_failure;
 434                 break;
 435         case NFT_CT_BYTES:
 436         case NFT_CT_PKTS:
 437                 if (priv->dir < IP_CT_DIR_MAX &&
 438                     nla_put_u8(skb, NFTA_CT_DIRECTION, priv->dir))
 439                         goto nla_put_failure;
 440                 break;
 441         default:
 442                 break;
 443         }
 444
 445         return 0;
 446
 447 nla_put_failure:
 448         return -1;
 449 }
 450
 451 static int nft_ct_set_dump(struct sk_buff *skb, const struct nft_expr *expr)
 452 {
 453         const struct nft_ct *priv = nft_expr_priv(expr);
 454
 455         if (nft_dump_register(skb, NFTA_CT_SREG, priv->sreg))
 456                 goto nla_put_failure;
 457         if (nla_put_be32(skb, NFTA_CT_KEY, htonl(priv->key)))
 458                 goto nla_put_failure;
 459         return 0;
 460
 461 nla_put_failure:
 462         return -1;
 463 }
 464
 465 static struct nft_expr_type nft_ct_type;
 466 static const struct nft_expr_ops nft_ct_get_ops = {
 467         .type           = &nft_ct_type,
 468         .size           = NFT_EXPR_SIZE(sizeof(struct nft_ct)),
 469         .eval           = nft_ct_get_eval,
 470         .init           = nft_ct_get_init,
 471         .destroy        = nft_ct_destroy,
 472         .dump           = nft_ct_get_dump,
 473 };
 474
 475 static const struct nft_expr_ops nft_ct_set_ops = {
 476         .type           = &nft_ct_type,
 477         .size           = NFT_EXPR_SIZE(sizeof(struct nft_ct)),
 478         .eval           = nft_ct_set_eval,
 479         .init           = nft_ct_set_init,
 480         .destroy        = nft_ct_destroy,
 481         .dump           = nft_ct_set_dump,
 482 };
 483
 484 static const struct nft_expr_ops *
 485 nft_ct_select_ops(const struct nft_ctx *ctx,
 486                     const struct nlattr * const tb[])
 487 {
 488         if (tb[NFTA_CT_KEY] == NULL)
 489                 return ERR_PTR(-EINVAL);
 490
 491         if (tb[NFTA_CT_DREG] && tb[NFTA_CT_SREG])
 492                 return ERR_PTR(-EINVAL);
 493
 494         if (tb[NFTA_CT_DREG])
 495                 return &nft_ct_get_ops;
 496
 497         if (tb[NFTA_CT_SREG])
 498                 return &nft_ct_set_ops;
 499
 500         return ERR_PTR(-EINVAL);
 501 }
 502
 503 static struct nft_expr_type nft_ct_type __read_mostly = {
 504         .name           = "ct",
 505         .select_ops     = &nft_ct_select_ops,
 506         .policy         = nft_ct_policy,
 507         .maxattr        = NFTA_CT_MAX,
 508         .owner          = THIS_MODULE,
 509 };
 510
 511 static int __init nft_ct_module_init(void)
 512 {
 513         BUILD_BUG_ON(NF_CT_LABELS_MAX_SIZE > NFT_REG_SIZE);
 514
 515         return nft_register_expr(&nft_ct_type);
 516 }
 517
 518 static void __exit nft_ct_module_exit(void)
 519 {
 520         nft_unregister_expr(&nft_ct_type);
 521 }
 522
 523 module_init(nft_ct_module_init);
 524 module_exit(nft_ct_module_exit);
 525
 526 MODULE_LICENSE("GPL");
 527 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 528 MODULE_ALIAS_NFT_EXPR("ct");