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         case NFT_META_CGROUP:
 170                 if (skb->sk == NULL || !sk_fullsock(skb->sk))
 171                         goto err;
 172                 *dest = skb->sk->sk_classid;
 173                 break;
 174         default:
 175                 WARN_ON(1);
 176                 goto err;
 177         }
 178         return;
 179
 180 err:
 181         regs->verdict.code = 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_regs *regs,
 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 = regs->data[meta->sreg];
 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         unsigned int len;
 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 = nft_parse_register(tb[NFTA_META_DREG]);
 261         return nft_validate_register_store(ctx, priv->dreg, NULL,
 262                                            NFT_DATA_VALUE, len);
 263 }
 264 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 265
 266 int nft_meta_set_init(const struct nft_ctx *ctx,
 267                       const struct nft_expr *expr,
 268                       const struct nlattr * const tb[])
 269 {
 270         struct nft_meta *priv = nft_expr_priv(expr);
 271         unsigned int len;
 272         int err;
 273
 274         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 275         switch (priv->key) {
 276         case NFT_META_MARK:
 277         case NFT_META_PRIORITY:
 278                 len = sizeof(u32);
 279                 break;
 280         case NFT_META_NFTRACE:
 281                 len = sizeof(u8);
 282                 break;
 283         default:
 284                 return -EOPNOTSUPP;
 285         }
 286
 287         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 288         err = nft_validate_register_load(priv->sreg, len);
 289         if (err < 0)
 290                 return err;
 291
 292         return 0;
 293 }
 294 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 295
 296 int nft_meta_get_dump(struct sk_buff *skb,
 297                       const struct nft_expr *expr)
 298 {
 299         const struct nft_meta *priv = nft_expr_priv(expr);
 300
 301         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 302                 goto nla_put_failure;
 303         if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
 304                 goto nla_put_failure;
 305         return 0;
 306
 307 nla_put_failure:
 308         return -1;
 309 }
 310 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 311
 312 int nft_meta_set_dump(struct sk_buff *skb,
 313                       const struct nft_expr *expr)
 314 {
 315         const struct nft_meta *priv = nft_expr_priv(expr);
 316
 317         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 318                 goto nla_put_failure;
 319         if (nft_dump_register(skb, NFTA_META_SREG, priv->sreg))
 320                 goto nla_put_failure;
 321
 322         return 0;
 323
 324 nla_put_failure:
 325         return -1;
 326 }
 327 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 328
 329 static struct nft_expr_type nft_meta_type;
 330 static const struct nft_expr_ops nft_meta_get_ops = {
 331         .type           = &nft_meta_type,
 332         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 333         .eval           = nft_meta_get_eval,
 334         .init           = nft_meta_get_init,
 335         .dump           = nft_meta_get_dump,
 336 };
 337
 338 static const struct nft_expr_ops nft_meta_set_ops = {
 339         .type           = &nft_meta_type,
 340         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 341         .eval           = nft_meta_set_eval,
 342         .init           = nft_meta_set_init,
 343         .dump           = nft_meta_set_dump,
 344 };
 345
 346 static const struct nft_expr_ops *
 347 nft_meta_select_ops(const struct nft_ctx *ctx,
 348                     const struct nlattr * const tb[])
 349 {
 350         if (tb[NFTA_META_KEY] == NULL)
 351                 return ERR_PTR(-EINVAL);
 352
 353         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 354                 return ERR_PTR(-EINVAL);
 355
 356         if (tb[NFTA_META_DREG])
 357                 return &nft_meta_get_ops;
 358
 359         if (tb[NFTA_META_SREG])
 360                 return &nft_meta_set_ops;
 361
 362         return ERR_PTR(-EINVAL);
 363 }
 364
 365 static struct nft_expr_type nft_meta_type __read_mostly = {
 366         .name           = "meta",
 367         .select_ops     = &nft_meta_select_ops,
 368         .policy         = nft_meta_policy,
 369         .maxattr        = NFTA_META_MAX,
 370         .owner          = THIS_MODULE,
 371 };
 372
 373 static int __init nft_meta_module_init(void)
 374 {
 375         return nft_register_expr(&nft_meta_type);
 376 }
 377
 378 static void __exit nft_meta_module_exit(void)
 379 {
 380         nft_unregister_expr(&nft_meta_type);
 381 }
 382
 383 module_init(nft_meta_module_init);
 384 module_exit(nft_meta_module_exit);
 385
 386 MODULE_LICENSE("GPL");
 387 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 388 MODULE_ALIAS_NFT_EXPR("meta");