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 || skb->sk->sk_state == TCP_TIME_WAIT)
  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 || skb->sk->sk_state == TCP_TIME_WAIT)
 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] = 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)
 170                         break;
 171
 172                 dest->data[0] = skb->sk->sk_classid;
 173                 break;
 174         default:
 175                 WARN_ON(1);
 176                 goto err;
 177         }
 178         return;
 179
 180 err:
 181         data[NFT_REG_VERDICT].verdict = NFT_BREAK;
 182 }
 183 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 184
 185 void nft_meta_set_eval(const struct nft_expr *expr,
 186                        struct nft_data data[NFT_REG_MAX + 1],
 187                        const struct nft_pktinfo *pkt)
 188 {
 189         const struct nft_meta *meta = nft_expr_priv(expr);
 190         struct sk_buff *skb = pkt->skb;
 191         u32 value = data[meta->sreg].data[0];
 192
 193         switch (meta->key) {
 194         case NFT_META_MARK:
 195                 skb->mark = value;
 196                 break;
 197         case NFT_META_PRIORITY:
 198                 skb->priority = value;
 199                 break;
 200         case NFT_META_NFTRACE:
 201                 skb->nf_trace = 1;
 202                 break;
 203         default:
 204                 WARN_ON(1);
 205         }
 206 }
 207 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 208
 209 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 210         [NFTA_META_DREG]        = { .type = NLA_U32 },
 211         [NFTA_META_KEY]         = { .type = NLA_U32 },
 212         [NFTA_META_SREG]        = { .type = NLA_U32 },
 213 };
 214 EXPORT_SYMBOL_GPL(nft_meta_policy);
 215
 216 int nft_meta_get_init(const struct nft_ctx *ctx,
 217                       const struct nft_expr *expr,
 218                       const struct nlattr * const tb[])
 219 {
 220         struct nft_meta *priv = nft_expr_priv(expr);
 221         int err;
 222
 223         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 224         switch (priv->key) {
 225         case NFT_META_LEN:
 226         case NFT_META_PROTOCOL:
 227         case NFT_META_NFPROTO:
 228         case NFT_META_L4PROTO:
 229         case NFT_META_PRIORITY:
 230         case NFT_META_MARK:
 231         case NFT_META_IIF:
 232         case NFT_META_OIF:
 233         case NFT_META_IIFNAME:
 234         case NFT_META_OIFNAME:
 235         case NFT_META_IIFTYPE:
 236         case NFT_META_OIFTYPE:
 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                 break;
 251         default:
 252                 return -EOPNOTSUPP;
 253         }
 254
 255         priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));
 256         err = nft_validate_output_register(priv->dreg);
 257         if (err < 0)
 258                 return err;
 259
 260         err = nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
 261         if (err < 0)
 262                 return err;
 263
 264         return 0;
 265 }
 266 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 267
 268 int nft_meta_set_init(const struct nft_ctx *ctx,
 269                       const struct nft_expr *expr,
 270                       const struct nlattr * const tb[])
 271 {
 272         struct nft_meta *priv = nft_expr_priv(expr);
 273         int err;
 274
 275         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 276         switch (priv->key) {
 277         case NFT_META_MARK:
 278         case NFT_META_PRIORITY:
 279         case NFT_META_NFTRACE:
 280                 break;
 281         default:
 282                 return -EOPNOTSUPP;
 283         }
 284
 285         priv->sreg = ntohl(nla_get_be32(tb[NFTA_META_SREG]));
 286         err = nft_validate_input_register(priv->sreg);
 287         if (err < 0)
 288                 return err;
 289
 290         return 0;
 291 }
 292 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 293
 294 int nft_meta_get_dump(struct sk_buff *skb,
 295                       const struct nft_expr *expr)
 296 {
 297         const struct nft_meta *priv = nft_expr_priv(expr);
 298
 299         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 300                 goto nla_put_failure;
 301         if (nla_put_be32(skb, NFTA_META_DREG, htonl(priv->dreg)))
 302                 goto nla_put_failure;
 303         return 0;
 304
 305 nla_put_failure:
 306         return -1;
 307 }
 308 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 309
 310 int nft_meta_set_dump(struct sk_buff *skb,
 311                       const struct nft_expr *expr)
 312 {
 313         const struct nft_meta *priv = nft_expr_priv(expr);
 314
 315         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 316                 goto nla_put_failure;
 317         if (nla_put_be32(skb, NFTA_META_SREG, htonl(priv->sreg)))
 318                 goto nla_put_failure;
 319
 320         return 0;
 321
 322 nla_put_failure:
 323         return -1;
 324 }
 325 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 326
 327 static struct nft_expr_type nft_meta_type;
 328 static const struct nft_expr_ops nft_meta_get_ops = {
 329         .type           = &nft_meta_type,
 330         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 331         .eval           = nft_meta_get_eval,
 332         .init           = nft_meta_get_init,
 333         .dump           = nft_meta_get_dump,
 334 };
 335
 336 static const struct nft_expr_ops nft_meta_set_ops = {
 337         .type           = &nft_meta_type,
 338         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 339         .eval           = nft_meta_set_eval,
 340         .init           = nft_meta_set_init,
 341         .dump           = nft_meta_set_dump,
 342 };
 343
 344 static const struct nft_expr_ops *
 345 nft_meta_select_ops(const struct nft_ctx *ctx,
 346                     const struct nlattr * const tb[])
 347 {
 348         if (tb[NFTA_META_KEY] == NULL)
 349                 return ERR_PTR(-EINVAL);
 350
 351         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 352                 return ERR_PTR(-EINVAL);
 353
 354         if (tb[NFTA_META_DREG])
 355                 return &nft_meta_get_ops;
 356
 357         if (tb[NFTA_META_SREG])
 358                 return &nft_meta_set_ops;
 359
 360         return ERR_PTR(-EINVAL);
 361 }
 362
 363 static struct nft_expr_type nft_meta_type __read_mostly = {
 364         .name           = "meta",
 365         .select_ops     = &nft_meta_select_ops,
 366         .policy         = nft_meta_policy,
 367         .maxattr        = NFTA_META_MAX,
 368         .owner          = THIS_MODULE,
 369 };
 370
 371 static int __init nft_meta_module_init(void)
 372 {
 373         return nft_register_expr(&nft_meta_type);
 374 }
 375
 376 static void __exit nft_meta_module_exit(void)
 377 {
 378         nft_unregister_expr(&nft_meta_type);
 379 }
 380
 381 module_init(nft_meta_module_init);
 382 module_exit(nft_meta_module_exit);
 383
 384 MODULE_LICENSE("GPL");
 385 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 386 MODULE_ALIAS_NFT_EXPR("meta");