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_tuple.h>
  20 #include <net/netfilter/nf_conntrack_helper.h>
  21 #include <net/netfilter/nf_conntrack_ecache.h>
  22
  23 struct nft_ct {
  24         enum nft_ct_keys        key:8;
  25         enum ip_conntrack_dir   dir:8;
  26         union{
  27                 enum nft_registers      dreg:8;
  28                 enum nft_registers      sreg:8;
  29         };
  30         uint8_t                 family;
  31 };
  32
  33 static void nft_ct_get_eval(const struct nft_expr *expr,
  34                             struct nft_data data[NFT_REG_MAX + 1],
  35                             const struct nft_pktinfo *pkt)
  36 {
  37         const struct nft_ct *priv = nft_expr_priv(expr);
  38         struct nft_data *dest = &data[priv->dreg];
  39         enum ip_conntrack_info ctinfo;
  40         const struct nf_conn *ct;
  41         const struct nf_conn_help *help;
  42         const struct nf_conntrack_tuple *tuple;
  43         const struct nf_conntrack_helper *helper;
  44         long diff;
  45         unsigned int state;
  46
  47         ct = nf_ct_get(pkt->skb, &ctinfo);
  48
  49         switch (priv->key) {
  50         case NFT_CT_STATE:
  51                 if (ct == NULL)
  52                         state = NF_CT_STATE_INVALID_BIT;
  53                 else if (nf_ct_is_untracked(ct))
  54                         state = NF_CT_STATE_UNTRACKED_BIT;
  55                 else
  56                         state = NF_CT_STATE_BIT(ctinfo);
  57                 dest->data[0] = state;
  58                 return;
  59         }
  60
  61         if (ct == NULL)
  62                 goto err;
  63
  64         switch (priv->key) {
  65         case NFT_CT_DIRECTION:
  66                 dest->data[0] = CTINFO2DIR(ctinfo);
  67                 return;
  68         case NFT_CT_STATUS:
  69                 dest->data[0] = ct->status;
  70                 return;
  71 #ifdef CONFIG_NF_CONNTRACK_MARK
  72         case NFT_CT_MARK:
  73                 dest->data[0] = ct->mark;
  74                 return;
  75 #endif
  76 #ifdef CONFIG_NF_CONNTRACK_SECMARK
  77         case NFT_CT_SECMARK:
  78                 dest->data[0] = ct->secmark;
  79                 return;
  80 #endif
  81         case NFT_CT_EXPIRATION:
  82                 diff = (long)jiffies - (long)ct->timeout.expires;
  83                 if (diff < 0)
  84                         diff = 0;
  85                 dest->data[0] = jiffies_to_msecs(diff);
  86                 return;
  87         case NFT_CT_HELPER:
  88                 if (ct->master == NULL)
  89                         goto err;
  90                 help = nfct_help(ct->master);
  91                 if (help == NULL)
  92                         goto err;
  93                 helper = rcu_dereference(help->helper);
  94                 if (helper == NULL)
  95                         goto err;
  96                 if (strlen(helper->name) >= sizeof(dest->data))
  97                         goto err;
  98                 strncpy((char *)dest->data, helper->name, sizeof(dest->data));
  99                 return;
 100         }
 101
 102         tuple = &ct->tuplehash[priv->dir].tuple;
 103         switch (priv->key) {
 104         case NFT_CT_L3PROTOCOL:
 105                 dest->data[0] = nf_ct_l3num(ct);
 106                 return;
 107         case NFT_CT_SRC:
 108                 memcpy(dest->data, tuple->src.u3.all,
 109                        nf_ct_l3num(ct) == NFPROTO_IPV4 ? 4 : 16);
 110                 return;
 111         case NFT_CT_DST:
 112                 memcpy(dest->data, tuple->dst.u3.all,
 113                        nf_ct_l3num(ct) == NFPROTO_IPV4 ? 4 : 16);
 114                 return;
 115         case NFT_CT_PROTOCOL:
 116                 dest->data[0] = nf_ct_protonum(ct);
 117                 return;
 118         case NFT_CT_PROTO_SRC:
 119                 dest->data[0] = (__force __u16)tuple->src.u.all;
 120                 return;
 121         case NFT_CT_PROTO_DST:
 122                 dest->data[0] = (__force __u16)tuple->dst.u.all;
 123                 return;
 124         }
 125         return;
 126 err:
 127         data[NFT_REG_VERDICT].verdict = NFT_BREAK;
 128 }
 129
 130 static void nft_ct_set_eval(const struct nft_expr *expr,
 131                             struct nft_data data[NFT_REG_MAX + 1],
 132                             const struct nft_pktinfo *pkt)
 133 {
 134         const struct nft_ct *priv = nft_expr_priv(expr);
 135         struct sk_buff *skb = pkt->skb;
 136 #ifdef CONFIG_NF_CONNTRACK_MARK
 137         u32 value = data[priv->sreg].data[0];
 138 #endif
 139         enum ip_conntrack_info ctinfo;
 140         struct nf_conn *ct;
 141
 142         ct = nf_ct_get(skb, &ctinfo);
 143         if (ct == NULL)
 144                 return;
 145
 146         switch (priv->key) {
 147 #ifdef CONFIG_NF_CONNTRACK_MARK
 148         case NFT_CT_MARK:
 149                 if (ct->mark != value) {
 150                         ct->mark = value;
 151                         nf_conntrack_event_cache(IPCT_MARK, ct);
 152                 }
 153                 break;
 154 #endif
 155         }
 156 }
 157
 158 static const struct nla_policy nft_ct_policy[NFTA_CT_MAX + 1] = {
 159         [NFTA_CT_DREG]          = { .type = NLA_U32 },
 160         [NFTA_CT_KEY]           = { .type = NLA_U32 },
 161         [NFTA_CT_DIRECTION]     = { .type = NLA_U8 },
 162         [NFTA_CT_SREG]          = { .type = NLA_U32 },
 163 };
 164
 165 static int nft_ct_l3proto_try_module_get(uint8_t family)
 166 {
 167         int err;
 168
 169         if (family == NFPROTO_INET) {
 170                 err = nf_ct_l3proto_try_module_get(NFPROTO_IPV4);
 171                 if (err < 0)
 172                         goto err1;
 173                 err = nf_ct_l3proto_try_module_get(NFPROTO_IPV6);
 174                 if (err < 0)
 175                         goto err2;
 176         } else {
 177                 err = nf_ct_l3proto_try_module_get(family);
 178                 if (err < 0)
 179                         goto err1;
 180         }
 181         return 0;
 182
 183 err2:
 184         nf_ct_l3proto_module_put(NFPROTO_IPV4);
 185 err1:
 186         return err;
 187 }
 188
 189 static void nft_ct_l3proto_module_put(uint8_t family)
 190 {
 191         if (family == NFPROTO_INET) {
 192                 nf_ct_l3proto_module_put(NFPROTO_IPV4);
 193                 nf_ct_l3proto_module_put(NFPROTO_IPV6);
 194         } else
 195                 nf_ct_l3proto_module_put(family);
 196 }
 197
 198 static int nft_ct_init_validate_get(const struct nft_expr *expr,
 199                                     const struct nlattr * const tb[])
 200 {
 201         struct nft_ct *priv = nft_expr_priv(expr);
 202
 203         if (tb[NFTA_CT_DIRECTION] != NULL) {
 204                 priv->dir = nla_get_u8(tb[NFTA_CT_DIRECTION]);
 205                 switch (priv->dir) {
 206                 case IP_CT_DIR_ORIGINAL:
 207                 case IP_CT_DIR_REPLY:
 208                         break;
 209                 default:
 210                         return -EINVAL;
 211                 }
 212         }
 213
 214         switch (priv->key) {
 215         case NFT_CT_STATE:
 216         case NFT_CT_DIRECTION:
 217         case NFT_CT_STATUS:
 218 #ifdef CONFIG_NF_CONNTRACK_MARK
 219         case NFT_CT_MARK:
 220 #endif
 221 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 222         case NFT_CT_SECMARK:
 223 #endif
 224         case NFT_CT_EXPIRATION:
 225         case NFT_CT_HELPER:
 226                 if (tb[NFTA_CT_DIRECTION] != NULL)
 227                         return -EINVAL;
 228                 break;
 229         case NFT_CT_PROTOCOL:
 230         case NFT_CT_SRC:
 231         case NFT_CT_DST:
 232         case NFT_CT_PROTO_SRC:
 233         case NFT_CT_PROTO_DST:
 234                 if (tb[NFTA_CT_DIRECTION] == NULL)
 235                         return -EINVAL;
 236                 break;
 237         default:
 238                 return -EOPNOTSUPP;
 239         }
 240
 241         return 0;
 242 }
 243
 244 static int nft_ct_init_validate_set(uint32_t key)
 245 {
 246         switch (key) {
 247         case NFT_CT_MARK:
 248                 break;
 249         default:
 250                 return -EOPNOTSUPP;
 251         }
 252
 253         return 0;
 254 }
 255
 256 static int nft_ct_init(const struct nft_ctx *ctx,
 257                        const struct nft_expr *expr,
 258                        const struct nlattr * const tb[])
 259 {
 260         struct nft_ct *priv = nft_expr_priv(expr);
 261         int err;
 262
 263         priv->key = ntohl(nla_get_be32(tb[NFTA_CT_KEY]));
 264
 265         if (tb[NFTA_CT_DREG]) {
 266                 err = nft_ct_init_validate_get(expr, tb);
 267                 if (err < 0)
 268                         return err;
 269
 270                 priv->dreg = ntohl(nla_get_be32(tb[NFTA_CT_DREG]));
 271                 err = nft_validate_output_register(priv->dreg);
 272                 if (err < 0)
 273                         return err;
 274
 275                 err = nft_validate_data_load(ctx, priv->dreg, NULL,
 276                                              NFT_DATA_VALUE);
 277                 if (err < 0)
 278                         return err;
 279         } else {
 280                 err = nft_ct_init_validate_set(priv->key);
 281                 if (err < 0)
 282                         return err;
 283
 284                 priv->sreg = ntohl(nla_get_be32(tb[NFTA_CT_SREG]));
 285                 err = nft_validate_input_register(priv->sreg);
 286                 if (err < 0)
 287                         return err;
 288         }
 289
 290         err = nft_ct_l3proto_try_module_get(ctx->afi->family);
 291         if (err < 0)
 292                 return err;
 293
 294         priv->family = ctx->afi->family;
 295
 296         return 0;
 297 }
 298
 299 static void nft_ct_destroy(const struct nft_expr *expr)
 300 {
 301         struct nft_ct *priv = nft_expr_priv(expr);
 302
 303         nft_ct_l3proto_module_put(priv->family);
 304 }
 305
 306 static int nft_ct_get_dump(struct sk_buff *skb, const struct nft_expr *expr)
 307 {
 308         const struct nft_ct *priv = nft_expr_priv(expr);
 309
 310         if (nla_put_be32(skb, NFTA_CT_DREG, htonl(priv->dreg)))
 311                 goto nla_put_failure;
 312         if (nla_put_be32(skb, NFTA_CT_KEY, htonl(priv->key)))
 313                 goto nla_put_failure;
 314         if (nla_put_u8(skb, NFTA_CT_DIRECTION, priv->dir))
 315                 goto nla_put_failure;
 316         return 0;
 317
 318 nla_put_failure:
 319         return -1;
 320 }
 321
 322 static int nft_ct_set_dump(struct sk_buff *skb, const struct nft_expr *expr)
 323 {
 324         const struct nft_ct *priv = nft_expr_priv(expr);
 325
 326         if (nla_put_be32(skb, NFTA_CT_SREG, htonl(priv->sreg)))
 327                 goto nla_put_failure;
 328         if (nla_put_be32(skb, NFTA_CT_KEY, htonl(priv->key)))
 329                 goto nla_put_failure;
 330         return 0;
 331
 332 nla_put_failure:
 333         return -1;
 334 }
 335
 336 static struct nft_expr_type nft_ct_type;
 337 static const struct nft_expr_ops nft_ct_get_ops = {
 338         .type           = &nft_ct_type,
 339         .size           = NFT_EXPR_SIZE(sizeof(struct nft_ct)),
 340         .eval           = nft_ct_get_eval,
 341         .init           = nft_ct_init,
 342         .destroy        = nft_ct_destroy,
 343         .dump           = nft_ct_get_dump,
 344 };
 345
 346 static const struct nft_expr_ops nft_ct_set_ops = {
 347         .type           = &nft_ct_type,
 348         .size           = NFT_EXPR_SIZE(sizeof(struct nft_ct)),
 349         .eval           = nft_ct_set_eval,
 350         .init           = nft_ct_init,
 351         .destroy        = nft_ct_destroy,
 352         .dump           = nft_ct_set_dump,
 353 };
 354
 355 static const struct nft_expr_ops *
 356 nft_ct_select_ops(const struct nft_ctx *ctx,
 357                     const struct nlattr * const tb[])
 358 {
 359         if (tb[NFTA_CT_KEY] == NULL)
 360                 return ERR_PTR(-EINVAL);
 361
 362         if (tb[NFTA_CT_DREG] && tb[NFTA_CT_SREG])
 363                 return ERR_PTR(-EINVAL);
 364
 365         if (tb[NFTA_CT_DREG])
 366                 return &nft_ct_get_ops;
 367
 368         if (tb[NFTA_CT_SREG])
 369                 return &nft_ct_set_ops;
 370
 371         return ERR_PTR(-EINVAL);
 372 }
 373
 374 static struct nft_expr_type nft_ct_type __read_mostly = {
 375         .name           = "ct",
 376         .select_ops     = &nft_ct_select_ops,
 377         .policy         = nft_ct_policy,
 378         .maxattr        = NFTA_CT_MAX,
 379         .owner          = THIS_MODULE,
 380 };
 381
 382 static int __init nft_ct_module_init(void)
 383 {
 384         return nft_register_expr(&nft_ct_type);
 385 }
 386
 387 static void __exit nft_ct_module_exit(void)
 388 {
 389         nft_unregister_expr(&nft_ct_type);
 390 }
 391
 392 module_init(nft_ct_module_init);
 393 module_exit(nft_ct_module_exit);
 394
 395 MODULE_LICENSE("GPL");
 396 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 397 MODULE_ALIAS_NFT_EXPR("ct");