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         u32 *dest = &regs->data[priv->dreg];
  35
  36         switch (priv->key) {
  37         case NFT_META_LEN:
  38                 *dest = skb->len;
  39                 break;
  40         case NFT_META_PROTOCOL:
  41                 *dest = 0;
  42                 *(__be16 *)dest = skb->protocol;
  43                 break;
  44         case NFT_META_NFPROTO:
  45                 *dest = pkt->ops->pf;
  46                 break;
  47         case NFT_META_L4PROTO:
  48                 *dest = pkt->tprot;
  49                 break;
  50         case NFT_META_PRIORITY:
  51                 *dest = skb->priority;
  52                 break;
  53         case NFT_META_MARK:
  54                 *dest = skb->mark;
  55                 break;
  56         case NFT_META_IIF:
  57                 if (in == NULL)
  58                         goto err;
  59                 *dest = in->ifindex;
  60                 break;
  61         case NFT_META_OIF:
  62                 if (out == NULL)
  63                         goto err;
  64                 *dest = out->ifindex;
  65                 break;
  66         case NFT_META_IIFNAME:
  67                 if (in == NULL)
  68                         goto err;
  69                 strncpy((char *)dest, in->name, IFNAMSIZ);
  70                 break;
  71         case NFT_META_OIFNAME:
  72                 if (out == NULL)
  73                         goto err;
  74                 strncpy((char *)dest, out->name, IFNAMSIZ);
  75                 break;
  76         case NFT_META_IIFTYPE:
  77                 if (in == NULL)
  78                         goto err;
  79                 *dest = 0;
  80                 *(u16 *)dest = in->type;
  81                 break;
  82         case NFT_META_OIFTYPE:
  83                 if (out == NULL)
  84                         goto err;
  85                 *dest = 0;
  86                 *(u16 *)dest = out->type;
  87                 break;
  88         case NFT_META_SKUID:
  89                 if (skb->sk == NULL || !sk_fullsock(skb->sk))
  90                         goto err;
  91
  92                 read_lock_bh(&skb->sk->sk_callback_lock);
  93                 if (skb->sk->sk_socket == NULL ||
  94                     skb->sk->sk_socket->file == NULL) {
  95                         read_unlock_bh(&skb->sk->sk_callback_lock);
  96                         goto err;
  97                 }
  98
  99                 *dest = from_kuid_munged(&init_user_ns,
 100                                 skb->sk->sk_socket->file->f_cred->fsuid);
 101                 read_unlock_bh(&skb->sk->sk_callback_lock);
 102                 break;
 103         case NFT_META_SKGID:
 104                 if (skb->sk == NULL || !sk_fullsock(skb->sk))
 105                         goto err;
 106
 107                 read_lock_bh(&skb->sk->sk_callback_lock);
 108                 if (skb->sk->sk_socket == NULL ||
 109                     skb->sk->sk_socket->file == NULL) {
 110                         read_unlock_bh(&skb->sk->sk_callback_lock);
 111                         goto err;
 112                 }
 113                 *dest = from_kgid_munged(&init_user_ns,
 114                                  skb->sk->sk_socket->file->f_cred->fsgid);
 115                 read_unlock_bh(&skb->sk->sk_callback_lock);
 116                 break;
 117 #ifdef CONFIG_IP_ROUTE_CLASSID
 118         case NFT_META_RTCLASSID: {
 119                 const struct dst_entry *dst = skb_dst(skb);
 120
 121                 if (dst == NULL)
 122                         goto err;
 123                 *dest = dst->tclassid;
 124                 break;
 125         }
 126 #endif
 127 #ifdef CONFIG_NETWORK_SECMARK
 128         case NFT_META_SECMARK:
 129                 *dest = skb->secmark;
 130                 break;
 131 #endif
 132         case NFT_META_PKTTYPE:
 133                 if (skb->pkt_type != PACKET_LOOPBACK) {
 134                         *dest = skb->pkt_type;
 135                         break;
 136                 }
 137
 138                 switch (pkt->ops->pf) {
 139                 case NFPROTO_IPV4:
 140                         if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 141                                 *dest = PACKET_MULTICAST;
 142                         else
 143                                 *dest = PACKET_BROADCAST;
 144                         break;
 145                 case NFPROTO_IPV6:
 146                         if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 147                                 *dest = PACKET_MULTICAST;
 148                         else
 149                                 *dest = PACKET_BROADCAST;
 150                         break;
 151                 default:
 152                         WARN_ON(1);
 153                         goto err;
 154                 }
 155                 break;
 156         case NFT_META_CPU:
 157                 *dest = raw_smp_processor_id();
 158                 break;
 159         case NFT_META_IIFGROUP:
 160                 if (in == NULL)
 161                         goto err;
 162                 *dest = in->group;
 163                 break;
 164         case NFT_META_OIFGROUP:
 165                 if (out == NULL)
 166                         goto err;
 167                 *dest = out->group;
 168                 break;
 169 #ifdef CONFIG_CGROUP_NET_CLASSID
 170         case NFT_META_CGROUP:
 171                 if (skb->sk == NULL || !sk_fullsock(skb->sk))
 172                         goto err;
 173                 *dest = skb->sk->sk_classid;
 174                 break;
 175 #endif
 176         default:
 177                 WARN_ON(1);
 178                 goto err;
 179         }
 180         return;
 181
 182 err:
 183         regs->verdict.code = NFT_BREAK;
 184 }
 185 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 186
 187 void nft_meta_set_eval(const struct nft_expr *expr,
 188                        struct nft_regs *regs,
 189                        const struct nft_pktinfo *pkt)
 190 {
 191         const struct nft_meta *meta = nft_expr_priv(expr);
 192         struct sk_buff *skb = pkt->skb;
 193         u32 value = regs->data[meta->sreg];
 194
 195         switch (meta->key) {
 196         case NFT_META_MARK:
 197                 skb->mark = value;
 198                 break;
 199         case NFT_META_PRIORITY:
 200                 skb->priority = value;
 201                 break;
 202         case NFT_META_NFTRACE:
 203                 skb->nf_trace = 1;
 204                 break;
 205         default:
 206                 WARN_ON(1);
 207         }
 208 }
 209 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 210
 211 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 212         [NFTA_META_DREG]        = { .type = NLA_U32 },
 213         [NFTA_META_KEY]         = { .type = NLA_U32 },
 214         [NFTA_META_SREG]        = { .type = NLA_U32 },
 215 };
 216 EXPORT_SYMBOL_GPL(nft_meta_policy);
 217
 218 int nft_meta_get_init(const struct nft_ctx *ctx,
 219                       const struct nft_expr *expr,
 220                       const struct nlattr * const tb[])
 221 {
 222         struct nft_meta *priv = nft_expr_priv(expr);
 223         unsigned int len;
 224
 225         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 226         switch (priv->key) {
 227         case NFT_META_PROTOCOL:
 228         case NFT_META_IIFTYPE:
 229         case NFT_META_OIFTYPE:
 230                 len = sizeof(u16);
 231                 break;
 232         case NFT_META_NFPROTO:
 233         case NFT_META_L4PROTO:
 234         case NFT_META_LEN:
 235         case NFT_META_PRIORITY:
 236         case NFT_META_MARK:
 237         case NFT_META_IIF:
 238         case NFT_META_OIF:
 239         case NFT_META_SKUID:
 240         case NFT_META_SKGID:
 241 #ifdef CONFIG_IP_ROUTE_CLASSID
 242         case NFT_META_RTCLASSID:
 243 #endif
 244 #ifdef CONFIG_NETWORK_SECMARK
 245         case NFT_META_SECMARK:
 246 #endif
 247         case NFT_META_PKTTYPE:
 248         case NFT_META_CPU:
 249         case NFT_META_IIFGROUP:
 250         case NFT_META_OIFGROUP:
 251 #ifdef CONFIG_CGROUP_NET_CLASSID
 252         case NFT_META_CGROUP:
 253 #endif
 254                 len = sizeof(u32);
 255                 break;
 256         case NFT_META_IIFNAME:
 257         case NFT_META_OIFNAME:
 258                 len = IFNAMSIZ;
 259                 break;
 260         default:
 261                 return -EOPNOTSUPP;
 262         }
 263
 264         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
 265         return nft_validate_register_store(ctx, priv->dreg, NULL,
 266                                            NFT_DATA_VALUE, len);
 267 }
 268 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 269
 270 int nft_meta_set_init(const struct nft_ctx *ctx,
 271                       const struct nft_expr *expr,
 272                       const struct nlattr * const tb[])
 273 {
 274         struct nft_meta *priv = nft_expr_priv(expr);
 275         unsigned int len;
 276         int err;
 277
 278         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 279         switch (priv->key) {
 280         case NFT_META_MARK:
 281         case NFT_META_PRIORITY:
 282                 len = sizeof(u32);
 283                 break;
 284         case NFT_META_NFTRACE:
 285                 len = sizeof(u8);
 286                 break;
 287         default:
 288                 return -EOPNOTSUPP;
 289         }
 290
 291         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 292         err = nft_validate_register_load(priv->sreg, len);
 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 (nft_dump_register(skb, NFTA_META_DREG, 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 (nft_dump_register(skb, NFTA_META_SREG, 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");