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_regs *regs,
  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 sock *sk;
  35         u32 *dest = &regs->data[priv->dreg];
  36
  37         switch (priv->key) {
  38         case NFT_META_LEN:
  39                 *dest = skb->len;
  40                 break;
  41         case NFT_META_PROTOCOL:
  42                 *dest = 0;
  43                 *(__be16 *)dest = skb->protocol;
  44                 break;
  45         case NFT_META_NFPROTO:
  46                 *dest = pkt->pf;
  47                 break;
  48         case NFT_META_L4PROTO:
  49                 *dest = pkt->tprot;
  50                 break;
  51         case NFT_META_PRIORITY:
  52                 *dest = skb->priority;
  53                 break;
  54         case NFT_META_MARK:
  55                 *dest = skb->mark;
  56                 break;
  57         case NFT_META_IIF:
  58                 if (in == NULL)
  59                         goto err;
  60                 *dest = in->ifindex;
  61                 break;
  62         case NFT_META_OIF:
  63                 if (out == NULL)
  64                         goto err;
  65                 *dest = out->ifindex;
  66                 break;
  67         case NFT_META_IIFNAME:
  68                 if (in == NULL)
  69                         goto err;
  70                 strncpy((char *)dest, in->name, IFNAMSIZ);
  71                 break;
  72         case NFT_META_OIFNAME:
  73                 if (out == NULL)
  74                         goto err;
  75                 strncpy((char *)dest, out->name, IFNAMSIZ);
  76                 break;
  77         case NFT_META_IIFTYPE:
  78                 if (in == NULL)
  79                         goto err;
  80                 *dest = 0;
  81                 *(u16 *)dest = in->type;
  82                 break;
  83         case NFT_META_OIFTYPE:
  84                 if (out == NULL)
  85                         goto err;
  86                 *dest = 0;
  87                 *(u16 *)dest = out->type;
  88                 break;
  89         case NFT_META_SKUID:
  90                 sk = skb_to_full_sk(skb);
  91                 if (!sk || !sk_fullsock(sk))
  92                         goto err;
  93
  94                 read_lock_bh(&sk->sk_callback_lock);
  95                 if (sk->sk_socket == NULL ||
  96                     sk->sk_socket->file == NULL) {
  97                         read_unlock_bh(&sk->sk_callback_lock);
  98                         goto err;
  99                 }
 100
 101                 *dest = from_kuid_munged(&init_user_ns,
 102                                 sk->sk_socket->file->f_cred->fsuid);
 103                 read_unlock_bh(&sk->sk_callback_lock);
 104                 break;
 105         case NFT_META_SKGID:
 106                 sk = skb_to_full_sk(skb);
 107                 if (!sk || !sk_fullsock(sk))
 108                         goto err;
 109
 110                 read_lock_bh(&sk->sk_callback_lock);
 111                 if (sk->sk_socket == NULL ||
 112                     sk->sk_socket->file == NULL) {
 113                         read_unlock_bh(&sk->sk_callback_lock);
 114                         goto err;
 115                 }
 116                 *dest = from_kgid_munged(&init_user_ns,
 117                                  sk->sk_socket->file->f_cred->fsgid);
 118                 read_unlock_bh(&sk->sk_callback_lock);
 119                 break;
 120 #ifdef CONFIG_IP_ROUTE_CLASSID
 121         case NFT_META_RTCLASSID: {
 122                 const struct dst_entry *dst = skb_dst(skb);
 123
 124                 if (dst == NULL)
 125                         goto err;
 126                 *dest = dst->tclassid;
 127                 break;
 128         }
 129 #endif
 130 #ifdef CONFIG_NETWORK_SECMARK
 131         case NFT_META_SECMARK:
 132                 *dest = skb->secmark;
 133                 break;
 134 #endif
 135         case NFT_META_PKTTYPE:
 136                 if (skb->pkt_type != PACKET_LOOPBACK) {
 137                         *dest = skb->pkt_type;
 138                         break;
 139                 }
 140
 141                 switch (pkt->pf) {
 142                 case NFPROTO_IPV4:
 143                         if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 144                                 *dest = PACKET_MULTICAST;
 145                         else
 146                                 *dest = PACKET_BROADCAST;
 147                         break;
 148                 case NFPROTO_IPV6:
 149                         if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 150                                 *dest = PACKET_MULTICAST;
 151                         else
 152                                 *dest = PACKET_BROADCAST;
 153                         break;
 154                 default:
 155                         WARN_ON(1);
 156                         goto err;
 157                 }
 158                 break;
 159         case NFT_META_CPU:
 160                 *dest = raw_smp_processor_id();
 161                 break;
 162         case NFT_META_IIFGROUP:
 163                 if (in == NULL)
 164                         goto err;
 165                 *dest = in->group;
 166                 break;
 167         case NFT_META_OIFGROUP:
 168                 if (out == NULL)
 169                         goto err;
 170                 *dest = out->group;
 171                 break;
 172 #ifdef CONFIG_CGROUP_NET_CLASSID
 173         case NFT_META_CGROUP:
 174                 sk = skb_to_full_sk(skb);
 175                 if (!sk || !sk_fullsock(sk))
 176                         goto err;
 177                 *dest = sk->sk_classid;
 178                 break;
 179 #endif
 180         default:
 181                 WARN_ON(1);
 182                 goto err;
 183         }
 184         return;
 185
 186 err:
 187         regs->verdict.code = NFT_BREAK;
 188 }
 189 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 190
 191 void nft_meta_set_eval(const struct nft_expr *expr,
 192                        struct nft_regs *regs,
 193                        const struct nft_pktinfo *pkt)
 194 {
 195         const struct nft_meta *meta = nft_expr_priv(expr);
 196         struct sk_buff *skb = pkt->skb;
 197         u32 value = regs->data[meta->sreg];
 198
 199         switch (meta->key) {
 200         case NFT_META_MARK:
 201                 skb->mark = value;
 202                 break;
 203         case NFT_META_PRIORITY:
 204                 skb->priority = value;
 205                 break;
 206         case NFT_META_NFTRACE:
 207                 skb->nf_trace = 1;
 208                 break;
 209         default:
 210                 WARN_ON(1);
 211         }
 212 }
 213 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 214
 215 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 216         [NFTA_META_DREG]        = { .type = NLA_U32 },
 217         [NFTA_META_KEY]         = { .type = NLA_U32 },
 218         [NFTA_META_SREG]        = { .type = NLA_U32 },
 219 };
 220 EXPORT_SYMBOL_GPL(nft_meta_policy);
 221
 222 int nft_meta_get_init(const struct nft_ctx *ctx,
 223                       const struct nft_expr *expr,
 224                       const struct nlattr * const tb[])
 225 {
 226         struct nft_meta *priv = nft_expr_priv(expr);
 227         unsigned int len;
 228
 229         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 230         switch (priv->key) {
 231         case NFT_META_PROTOCOL:
 232         case NFT_META_IIFTYPE:
 233         case NFT_META_OIFTYPE:
 234                 len = sizeof(u16);
 235                 break;
 236         case NFT_META_NFPROTO:
 237         case NFT_META_L4PROTO:
 238         case NFT_META_LEN:
 239         case NFT_META_PRIORITY:
 240         case NFT_META_MARK:
 241         case NFT_META_IIF:
 242         case NFT_META_OIF:
 243         case NFT_META_SKUID:
 244         case NFT_META_SKGID:
 245 #ifdef CONFIG_IP_ROUTE_CLASSID
 246         case NFT_META_RTCLASSID:
 247 #endif
 248 #ifdef CONFIG_NETWORK_SECMARK
 249         case NFT_META_SECMARK:
 250 #endif
 251         case NFT_META_PKTTYPE:
 252         case NFT_META_CPU:
 253         case NFT_META_IIFGROUP:
 254         case NFT_META_OIFGROUP:
 255 #ifdef CONFIG_CGROUP_NET_CLASSID
 256         case NFT_META_CGROUP:
 257 #endif
 258                 len = sizeof(u32);
 259                 break;
 260         case NFT_META_IIFNAME:
 261         case NFT_META_OIFNAME:
 262                 len = IFNAMSIZ;
 263                 break;
 264         default:
 265                 return -EOPNOTSUPP;
 266         }
 267
 268         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
 269         return nft_validate_register_store(ctx, priv->dreg, NULL,
 270                                            NFT_DATA_VALUE, len);
 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         unsigned int len;
 280         int err;
 281
 282         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 283         switch (priv->key) {
 284         case NFT_META_MARK:
 285         case NFT_META_PRIORITY:
 286                 len = sizeof(u32);
 287                 break;
 288         case NFT_META_NFTRACE:
 289                 len = sizeof(u8);
 290                 break;
 291         default:
 292                 return -EOPNOTSUPP;
 293         }
 294
 295         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 296         err = nft_validate_register_load(priv->sreg, len);
 297         if (err < 0)
 298                 return err;
 299
 300         return 0;
 301 }
 302 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 303
 304 int nft_meta_get_dump(struct sk_buff *skb,
 305                       const struct nft_expr *expr)
 306 {
 307         const struct nft_meta *priv = nft_expr_priv(expr);
 308
 309         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 310                 goto nla_put_failure;
 311         if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
 312                 goto nla_put_failure;
 313         return 0;
 314
 315 nla_put_failure:
 316         return -1;
 317 }
 318 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 319
 320 int nft_meta_set_dump(struct sk_buff *skb,
 321                       const struct nft_expr *expr)
 322 {
 323         const struct nft_meta *priv = nft_expr_priv(expr);
 324
 325         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 326                 goto nla_put_failure;
 327         if (nft_dump_register(skb, NFTA_META_SREG, priv->sreg))
 328                 goto nla_put_failure;
 329
 330         return 0;
 331
 332 nla_put_failure:
 333         return -1;
 334 }
 335 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 336
 337 static struct nft_expr_type nft_meta_type;
 338 static const struct nft_expr_ops nft_meta_get_ops = {
 339         .type           = &nft_meta_type,
 340         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 341         .eval           = nft_meta_get_eval,
 342         .init           = nft_meta_get_init,
 343         .dump           = nft_meta_get_dump,
 344 };
 345
 346 static const struct nft_expr_ops nft_meta_set_ops = {
 347         .type           = &nft_meta_type,
 348         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 349         .eval           = nft_meta_set_eval,
 350         .init           = nft_meta_set_init,
 351         .dump           = nft_meta_set_dump,
 352 };
 353
 354 static const struct nft_expr_ops *
 355 nft_meta_select_ops(const struct nft_ctx *ctx,
 356                     const struct nlattr * const tb[])
 357 {
 358         if (tb[NFTA_META_KEY] == NULL)
 359                 return ERR_PTR(-EINVAL);
 360
 361         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 362                 return ERR_PTR(-EINVAL);
 363
 364         if (tb[NFTA_META_DREG])
 365                 return &nft_meta_get_ops;
 366
 367         if (tb[NFTA_META_SREG])
 368                 return &nft_meta_set_ops;
 369
 370         return ERR_PTR(-EINVAL);
 371 }
 372
 373 static struct nft_expr_type nft_meta_type __read_mostly = {
 374         .name           = "meta",
 375         .select_ops     = &nft_meta_select_ops,
 376         .policy         = nft_meta_policy,
 377         .maxattr        = NFTA_META_MAX,
 378         .owner          = THIS_MODULE,
 379 };
 380
 381 static int __init nft_meta_module_init(void)
 382 {
 383         return nft_register_expr(&nft_meta_type);
 384 }
 385
 386 static void __exit nft_meta_module_exit(void)
 387 {
 388         nft_unregister_expr(&nft_meta_type);
 389 }
 390
 391 module_init(nft_meta_module_init);
 392 module_exit(nft_meta_module_exit);
 393
 394 MODULE_LICENSE("GPL");
 395 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 396 MODULE_ALIAS_NFT_EXPR("meta");