net/netfilter/nf_tables_core.c

   1 /*
   2  * Copyright (c) 2008 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/module.h>
  13 #include <linux/init.h>
  14 #include <linux/list.h>
  15 #include <linux/rculist.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/netlink.h>
  18 #include <linux/netfilter.h>
  19 #include <linux/static_key.h>
  20 #include <linux/netfilter/nfnetlink.h>
  21 #include <linux/netfilter/nf_tables.h>
  22 #include <net/netfilter/nf_tables_core.h>
  23 #include <net/netfilter/nf_tables.h>
  24 #include <net/netfilter/nf_log.h>
  25
  26 static const char *const comments[__NFT_TRACETYPE_MAX] = {
  27         [NFT_TRACETYPE_POLICY]  = "policy",
  28         [NFT_TRACETYPE_RETURN]  = "return",
  29         [NFT_TRACETYPE_RULE]    = "rule",
  30 };
  31
  32 static struct nf_loginfo trace_loginfo = {
  33         .type = NF_LOG_TYPE_LOG,
  34         .u = {
  35                 .log = {
  36                         .level = LOGLEVEL_WARNING,
  37                         .logflags = NF_LOG_DEFAULT_MASK,
  38                 },
  39         },
  40 };
  41
  42 static noinline void __nft_trace_packet(struct nft_traceinfo *info,
  43                                         const struct nft_chain *chain,
  44                                         int rulenum, enum nft_trace_types type)
  45 {
  46         const struct nft_pktinfo *pkt = info->pkt;
  47
  48         if (!info->trace || !pkt->skb->nf_trace)
  49                 return;
  50
  51         info->chain = chain;
  52         info->type = type;
  53
  54         nft_trace_notify(info);
  55
  56         nf_log_trace(pkt->net, pkt->pf, pkt->hook, pkt->skb, pkt->in,
  57                      pkt->out, &trace_loginfo, "TRACE: %s:%s:%s:%u ",
  58                      chain->table->name, chain->name, comments[type],
  59                      rulenum);
  60 }
  61
  62 static inline void nft_trace_packet(struct nft_traceinfo *info,
  63                                     const struct nft_chain *chain,
  64                                     const struct nft_rule *rule,
  65                                     int rulenum,
  66                                     enum nft_trace_types type)
  67 {
  68         if (static_branch_unlikely(&nft_trace_enabled)) {
  69                 info->rule = rule;
  70                 __nft_trace_packet(info, chain, rulenum, type);
  71         }
  72 }
  73
  74 static void nft_cmp_fast_eval(const struct nft_expr *expr,
  75                               struct nft_regs *regs)
  76 {
  77         const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
  78         u32 mask = nft_cmp_fast_mask(priv->len);
  79
  80         if ((regs->data[priv->sreg] & mask) == priv->data)
  81                 return;
  82         regs->verdict.code = NFT_BREAK;
  83 }
  84
  85 static bool nft_payload_fast_eval(const struct nft_expr *expr,
  86                                   struct nft_regs *regs,
  87                                   const struct nft_pktinfo *pkt)
  88 {
  89         const struct nft_payload *priv = nft_expr_priv(expr);
  90         const struct sk_buff *skb = pkt->skb;
  91         u32 *dest = &regs->data[priv->dreg];
  92         unsigned char *ptr;
  93
  94         if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
  95                 ptr = skb_network_header(skb);
  96         else {
  97                 if (!pkt->tprot_set)
  98                         return false;
  99                 ptr = skb_network_header(skb) + pkt->xt.thoff;
 100         }
 101
 102         ptr += priv->offset;
 103
 104         if (unlikely(ptr + priv->len > skb_tail_pointer(skb)))
 105                 return false;
 106
 107         *dest = 0;
 108         if (priv->len == 2)
 109                 *(u16 *)dest = *(u16 *)ptr;
 110         else if (priv->len == 4)
 111                 *(u32 *)dest = *(u32 *)ptr;
 112         else
 113                 *(u8 *)dest = *(u8 *)ptr;
 114         return true;
 115 }
 116
 117 struct nft_jumpstack {
 118         const struct nft_chain  *chain;
 119         const struct nft_rule   *rule;
 120         int                     rulenum;
 121 };
 122
 123 unsigned int
 124 nft_do_chain(struct nft_pktinfo *pkt, void *priv)
 125 {
 126         const struct nft_chain *chain = priv, *basechain = chain;
 127         const struct net *net = pkt->net;
 128         const struct nft_rule *rule;
 129         const struct nft_expr *expr, *last;
 130         struct nft_regs regs;
 131         unsigned int stackptr = 0;
 132         struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
 133         struct nft_stats *stats;
 134         int rulenum;
 135         unsigned int gencursor = nft_genmask_cur(net);
 136         struct nft_traceinfo info;
 137
 138         info.trace = false;
 139         if (static_branch_unlikely(&nft_trace_enabled))
 140                 nft_trace_init(&info, pkt, &regs.verdict, basechain);
 141 do_chain:
 142         rulenum = 0;
 143         rule = list_entry(&chain->rules, struct nft_rule, list);
 144 next_rule:
 145         regs.verdict.code = NFT_CONTINUE;
 146         list_for_each_entry_continue_rcu(rule, &chain->rules, list) {
 147
 148                 /* This rule is not active, skip. */
 149                 if (unlikely(rule->genmask & gencursor))
 150                         continue;
 151
 152                 rulenum++;
 153
 154                 nft_rule_for_each_expr(expr, last, rule) {
 155                         if (expr->ops == &nft_cmp_fast_ops)
 156                                 nft_cmp_fast_eval(expr, &regs);
 157                         else if (expr->ops != &nft_payload_fast_ops ||
 158                                  !nft_payload_fast_eval(expr, &regs, pkt))
 159                                 expr->ops->eval(expr, &regs, pkt);
 160
 161                         if (regs.verdict.code != NFT_CONTINUE)
 162                                 break;
 163                 }
 164
 165                 switch (regs.verdict.code) {
 166                 case NFT_BREAK:
 167                         regs.verdict.code = NFT_CONTINUE;
 168                         continue;
 169                 case NFT_CONTINUE:
 170                         nft_trace_packet(&info, chain, rule,
 171                                          rulenum, NFT_TRACETYPE_RULE);
 172                         continue;
 173                 }
 174                 break;
 175         }
 176
 177         switch (regs.verdict.code & NF_VERDICT_MASK) {
 178         case NF_ACCEPT:
 179         case NF_DROP:
 180         case NF_QUEUE:
 181                 nft_trace_packet(&info, chain, rule,
 182                                  rulenum, NFT_TRACETYPE_RULE);
 183                 return regs.verdict.code;
 184         }
 185
 186         switch (regs.verdict.code) {
 187         case NFT_JUMP:
 188                 BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
 189                 jumpstack[stackptr].chain = chain;
 190                 jumpstack[stackptr].rule  = rule;
 191                 jumpstack[stackptr].rulenum = rulenum;
 192                 stackptr++;
 193                 /* fall through */
 194         case NFT_GOTO:
 195                 nft_trace_packet(&info, chain, rule,
 196                                  rulenum, NFT_TRACETYPE_RULE);
 197
 198                 chain = regs.verdict.chain;
 199                 goto do_chain;
 200         case NFT_CONTINUE:
 201                 rulenum++;
 202                 /* fall through */
 203         case NFT_RETURN:
 204                 nft_trace_packet(&info, chain, rule,
 205                                  rulenum, NFT_TRACETYPE_RETURN);
 206                 break;
 207         default:
 208                 WARN_ON(1);
 209         }
 210
 211         if (stackptr > 0) {
 212                 stackptr--;
 213                 chain = jumpstack[stackptr].chain;
 214                 rule  = jumpstack[stackptr].rule;
 215                 rulenum = jumpstack[stackptr].rulenum;
 216                 goto next_rule;
 217         }
 218
 219         nft_trace_packet(&info, basechain, NULL, -1,
 220                          NFT_TRACETYPE_POLICY);
 221
 222         rcu_read_lock_bh();
 223         stats = this_cpu_ptr(rcu_dereference(nft_base_chain(basechain)->stats));
 224         u64_stats_update_begin(&stats->syncp);
 225         stats->pkts++;
 226         stats->bytes += pkt->skb->len;
 227         u64_stats_update_end(&stats->syncp);
 228         rcu_read_unlock_bh();
 229
 230         return nft_base_chain(basechain)->policy;
 231 }
 232 EXPORT_SYMBOL_GPL(nft_do_chain);
 233
 234 int __init nf_tables_core_module_init(void)
 235 {
 236         int err;
 237
 238         err = nft_immediate_module_init();
 239         if (err < 0)
 240                 goto err1;
 241
 242         err = nft_cmp_module_init();
 243         if (err < 0)
 244                 goto err2;
 245
 246         err = nft_lookup_module_init();
 247         if (err < 0)
 248                 goto err3;
 249
 250         err = nft_bitwise_module_init();
 251         if (err < 0)
 252                 goto err4;
 253
 254         err = nft_byteorder_module_init();
 255         if (err < 0)
 256                 goto err5;
 257
 258         err = nft_payload_module_init();
 259         if (err < 0)
 260                 goto err6;
 261
 262         err = nft_dynset_module_init();
 263         if (err < 0)
 264                 goto err7;
 265
 266         err = nft_range_module_init();
 267         if (err < 0)
 268                 goto err8;
 269
 270         return 0;
 271 err8:
 272         nft_dynset_module_exit();
 273 err7:
 274         nft_payload_module_exit();
 275 err6:
 276         nft_byteorder_module_exit();
 277 err5:
 278         nft_bitwise_module_exit();
 279 err4:
 280         nft_lookup_module_exit();
 281 err3:
 282         nft_cmp_module_exit();
 283 err2:
 284         nft_immediate_module_exit();
 285 err1:
 286         return err;
 287 }
 288
 289 void nf_tables_core_module_exit(void)
 290 {
 291         nft_dynset_module_exit();
 292         nft_payload_module_exit();
 293         nft_byteorder_module_exit();
 294         nft_bitwise_module_exit();
 295         nft_lookup_module_exit();
 296         nft_cmp_module_exit();
 297         nft_immediate_module_exit();
 298 }