net/netfilter/nft_meta.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 <linux/in.h>
  18 #include <linux/ip.h>
  19 #include <linux/ipv6.h>
  20 #include <linux/smp.h>
  21 #include <net/dst.h>
  22 #include <net/sock.h>
  23 #include <net/tcp_states.h> /* for TCP_TIME_WAIT */
  24 #include <net/netfilter/nf_tables.h>
  25 #include <net/netfilter/nft_meta.h>
  26
  27 void nft_meta_get_eval(const struct nft_expr *expr,
  28                        struct nft_data data[NFT_REG_MAX + 1],
  29                        const struct nft_pktinfo *pkt)
  30 {
  31         const struct nft_meta *priv = nft_expr_priv(expr);
  32         const struct sk_buff *skb = pkt->skb;
  33         const struct net_device *in = pkt->in, *out = pkt->out;
  34         struct nft_data *dest = &data[priv->dreg];
  35
  36         switch (priv->key) {
  37         case NFT_META_LEN:
  38                 dest->data[0] = skb->len;
  39                 break;
  40         case NFT_META_PROTOCOL:
  41                 *(__be16 *)dest->data = skb->protocol;
  42                 break;
  43         case NFT_META_NFPROTO:
  44                 dest->data[0] = pkt->ops->pf;
  45                 break;
  46         case NFT_META_L4PROTO:
  47                 dest->data[0] = pkt->tprot;
  48                 break;
  49         case NFT_META_PRIORITY:
  50                 dest->data[0] = skb->priority;
  51                 break;
  52         case NFT_META_MARK:
  53                 dest->data[0] = skb->mark;
  54                 break;
  55         case NFT_META_IIF:
  56                 if (in == NULL)
  57                         goto err;
  58                 dest->data[0] = in->ifindex;
  59                 break;
  60         case NFT_META_OIF:
  61                 if (out == NULL)
  62                         goto err;
  63                 dest->data[0] = out->ifindex;
  64                 break;
  65         case NFT_META_IIFNAME:
  66                 if (in == NULL)
  67                         goto err;
  68                 strncpy((char *)dest->data, in->name, sizeof(dest->data));
  69                 break;
  70         case NFT_META_OIFNAME:
  71                 if (out == NULL)
  72                         goto err;
  73                 strncpy((char *)dest->data, out->name, sizeof(dest->data));
  74                 break;
  75         case NFT_META_IIFTYPE:
  76                 if (in == NULL)
  77                         goto err;
  78                 *(u16 *)dest->data = in->type;
  79                 break;
  80         case NFT_META_OIFTYPE:
  81                 if (out == NULL)
  82                         goto err;
  83                 *(u16 *)dest->data = out->type;
  84                 break;
  85         case NFT_META_SKUID:
  86                 if (skb->sk == NULL || !sk_fullsock(skb->sk))
  87                         goto err;
  88
  89                 read_lock_bh(&skb->sk->sk_callback_lock);
  90                 if (skb->sk->sk_socket == NULL ||
  91                     skb->sk->sk_socket->file == NULL) {
  92                         read_unlock_bh(&skb->sk->sk_callback_lock);
  93                         goto err;
  94                 }
  95
  96                 dest->data[0] =
  97                         from_kuid_munged(&init_user_ns,
  98                                 skb->sk->sk_socket->file->f_cred->fsuid);
  99                 read_unlock_bh(&skb->sk->sk_callback_lock);
 100                 break;
 101         case NFT_META_SKGID:
 102                 if (skb->sk == NULL || !sk_fullsock(skb->sk))
 103                         goto err;
 104
 105                 read_lock_bh(&skb->sk->sk_callback_lock);
 106                 if (skb->sk->sk_socket == NULL ||
 107                     skb->sk->sk_socket->file == NULL) {
 108                         read_unlock_bh(&skb->sk->sk_callback_lock);
 109                         goto err;
 110                 }
 111                 dest->data[0] =
 112                         from_kgid_munged(&init_user_ns,
 113                                  skb->sk->sk_socket->file->f_cred->fsgid);
 114                 read_unlock_bh(&skb->sk->sk_callback_lock);
 115                 break;
 116 #ifdef CONFIG_IP_ROUTE_CLASSID
 117         case NFT_META_RTCLASSID: {
 118                 const struct dst_entry *dst = skb_dst(skb);
 119
 120                 if (dst == NULL)
 121                         goto err;
 122                 dest->data[0] = dst->tclassid;
 123                 break;
 124         }
 125 #endif
 126 #ifdef CONFIG_NETWORK_SECMARK
 127         case NFT_META_SECMARK:
 128                 dest->data[0] = skb->secmark;
 129                 break;
 130 #endif
 131         case NFT_META_PKTTYPE:
 132                 if (skb->pkt_type != PACKET_LOOPBACK) {
 133                         dest->data[0] = skb->pkt_type;
 134                         break;
 135                 }
 136
 137                 switch (pkt->ops->pf) {
 138                 case NFPROTO_IPV4:
 139                         if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 140                                 dest->data[0] = PACKET_MULTICAST;
 141                         else
 142                                 dest->data[0] = PACKET_BROADCAST;
 143                         break;
 144                 case NFPROTO_IPV6:
 145                         if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 146                                 dest->data[0] = PACKET_MULTICAST;
 147                         else
 148                                 dest->data[0] = PACKET_BROADCAST;
 149                         break;
 150                 default:
 151                         WARN_ON(1);
 152                         goto err;
 153                 }
 154                 break;
 155         case NFT_META_CPU:
 156                 dest->data[0] = raw_smp_processor_id();
 157                 break;
 158         case NFT_META_IIFGROUP:
 159                 if (in == NULL)
 160                         goto err;
 161                 dest->data[0] = in->group;
 162                 break;
 163         case NFT_META_OIFGROUP:
 164                 if (out == NULL)
 165                         goto err;
 166                 dest->data[0] = out->group;
 167                 break;
 168         case NFT_META_CGROUP:
 169                 if (skb->sk == NULL || !sk_fullsock(skb->sk))
 170                         goto err;
 171                 dest->data[0] = skb->sk->sk_classid;
 172                 break;
 173         default:
 174                 WARN_ON(1);
 175                 goto err;
 176         }
 177         return;
 178
 179 err:
 180         data[NFT_REG_VERDICT].verdict = NFT_BREAK;
 181 }
 182 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 183
 184 void nft_meta_set_eval(const struct nft_expr *expr,
 185                        struct nft_data data[NFT_REG_MAX + 1],
 186                        const struct nft_pktinfo *pkt)
 187 {
 188         const struct nft_meta *meta = nft_expr_priv(expr);
 189         struct sk_buff *skb = pkt->skb;
 190         u32 value = data[meta->sreg].data[0];
 191
 192         switch (meta->key) {
 193         case NFT_META_MARK:
 194                 skb->mark = value;
 195                 break;
 196         case NFT_META_PRIORITY:
 197                 skb->priority = value;
 198                 break;
 199         case NFT_META_NFTRACE:
 200                 skb->nf_trace = 1;
 201                 break;
 202         default:
 203                 WARN_ON(1);
 204         }
 205 }
 206 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 207
 208 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 209         [NFTA_META_DREG]        = { .type = NLA_U32 },
 210         [NFTA_META_KEY]         = { .type = NLA_U32 },
 211         [NFTA_META_SREG]        = { .type = NLA_U32 },
 212 };
 213 EXPORT_SYMBOL_GPL(nft_meta_policy);
 214
 215 int nft_meta_get_init(const struct nft_ctx *ctx,
 216                       const struct nft_expr *expr,
 217                       const struct nlattr * const tb[])
 218 {
 219         struct nft_meta *priv = nft_expr_priv(expr);
 220         unsigned int len;
 221         int err;
 222
 223         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 224         switch (priv->key) {
 225         case NFT_META_PROTOCOL:
 226         case NFT_META_IIFTYPE:
 227         case NFT_META_OIFTYPE:
 228                 len = sizeof(u16);
 229                 break;
 230         case NFT_META_NFPROTO:
 231         case NFT_META_L4PROTO:
 232         case NFT_META_LEN:
 233         case NFT_META_PRIORITY:
 234         case NFT_META_MARK:
 235         case NFT_META_IIF:
 236         case NFT_META_OIF:
 237         case NFT_META_SKUID:
 238         case NFT_META_SKGID:
 239 #ifdef CONFIG_IP_ROUTE_CLASSID
 240         case NFT_META_RTCLASSID:
 241 #endif
 242 #ifdef CONFIG_NETWORK_SECMARK
 243         case NFT_META_SECMARK:
 244 #endif
 245         case NFT_META_PKTTYPE:
 246         case NFT_META_CPU:
 247         case NFT_META_IIFGROUP:
 248         case NFT_META_OIFGROUP:
 249         case NFT_META_CGROUP:
 250                 len = sizeof(u32);
 251                 break;
 252         case NFT_META_IIFNAME:
 253         case NFT_META_OIFNAME:
 254                 len = IFNAMSIZ;
 255                 break;
 256         default:
 257                 return -EOPNOTSUPP;
 258         }
 259
 260         priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));
 261         err = nft_validate_output_register(priv->dreg);
 262         if (err < 0)
 263                 return err;
 264
 265         err = nft_validate_register_store(ctx, priv->dreg, NULL,
 266                                           NFT_DATA_VALUE, len);
 267         if (err < 0)
 268                 return err;
 269
 270         return 0;
 271 }
 272 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 273
 274 int nft_meta_set_init(const struct nft_ctx *ctx,
 275                       const struct nft_expr *expr,
 276                       const struct nlattr * const tb[])
 277 {
 278         struct nft_meta *priv = nft_expr_priv(expr);
 279         int err;
 280
 281         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 282         switch (priv->key) {
 283         case NFT_META_MARK:
 284         case NFT_META_PRIORITY:
 285         case NFT_META_NFTRACE:
 286                 break;
 287         default:
 288                 return -EOPNOTSUPP;
 289         }
 290
 291         priv->sreg = ntohl(nla_get_be32(tb[NFTA_META_SREG]));
 292         err = nft_validate_input_register(priv->sreg);
 293         if (err < 0)
 294                 return err;
 295
 296         return 0;
 297 }
 298 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 299
 300 int nft_meta_get_dump(struct sk_buff *skb,
 301                       const struct nft_expr *expr)
 302 {
 303         const struct nft_meta *priv = nft_expr_priv(expr);
 304
 305         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 306                 goto nla_put_failure;
 307         if (nla_put_be32(skb, NFTA_META_DREG, htonl(priv->dreg)))
 308                 goto nla_put_failure;
 309         return 0;
 310
 311 nla_put_failure:
 312         return -1;
 313 }
 314 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 315
 316 int nft_meta_set_dump(struct sk_buff *skb,
 317                       const struct nft_expr *expr)
 318 {
 319         const struct nft_meta *priv = nft_expr_priv(expr);
 320
 321         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 322                 goto nla_put_failure;
 323         if (nla_put_be32(skb, NFTA_META_SREG, htonl(priv->sreg)))
 324                 goto nla_put_failure;
 325
 326         return 0;
 327
 328 nla_put_failure:
 329         return -1;
 330 }
 331 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 332
 333 static struct nft_expr_type nft_meta_type;
 334 static const struct nft_expr_ops nft_meta_get_ops = {
 335         .type           = &nft_meta_type,
 336         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 337         .eval           = nft_meta_get_eval,
 338         .init           = nft_meta_get_init,
 339         .dump           = nft_meta_get_dump,
 340 };
 341
 342 static const struct nft_expr_ops nft_meta_set_ops = {
 343         .type           = &nft_meta_type,
 344         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 345         .eval           = nft_meta_set_eval,
 346         .init           = nft_meta_set_init,
 347         .dump           = nft_meta_set_dump,
 348 };
 349
 350 static const struct nft_expr_ops *
 351 nft_meta_select_ops(const struct nft_ctx *ctx,
 352                     const struct nlattr * const tb[])
 353 {
 354         if (tb[NFTA_META_KEY] == NULL)
 355                 return ERR_PTR(-EINVAL);
 356
 357         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 358                 return ERR_PTR(-EINVAL);
 359
 360         if (tb[NFTA_META_DREG])
 361                 return &nft_meta_get_ops;
 362
 363         if (tb[NFTA_META_SREG])
 364                 return &nft_meta_set_ops;
 365
 366         return ERR_PTR(-EINVAL);
 367 }
 368
 369 static struct nft_expr_type nft_meta_type __read_mostly = {
 370         .name           = "meta",
 371         .select_ops     = &nft_meta_select_ops,
 372         .policy         = nft_meta_policy,
 373         .maxattr        = NFTA_META_MAX,
 374         .owner          = THIS_MODULE,
 375 };
 376
 377 static int __init nft_meta_module_init(void)
 378 {
 379         return nft_register_expr(&nft_meta_type);
 380 }
 381
 382 static void __exit nft_meta_module_exit(void)
 383 {
 384         nft_unregister_expr(&nft_meta_type);
 385 }
 386
 387 module_init(nft_meta_module_init);
 388 module_exit(nft_meta_module_exit);
 389
 390 MODULE_LICENSE("GPL");
 391 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 392 MODULE_ALIAS_NFT_EXPR("meta");