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_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                 ptr = skb_network_header(skb) + pkt->xt.thoff;
  98
  99         ptr += priv->offset;
 100
 101         if (unlikely(ptr + priv->len >= skb_tail_pointer(skb)))
 102                 return false;
 103
 104         *dest = 0;
 105         if (priv->len == 2)
 106                 *(u16 *)dest = *(u16 *)ptr;
 107         else if (priv->len == 4)
 108                 *(u32 *)dest = *(u32 *)ptr;
 109         else
 110                 *(u8 *)dest = *(u8 *)ptr;
 111         return true;
 112 }
 113
 114 struct nft_jumpstack {
 115         const struct nft_chain  *chain;
 116         const struct nft_rule   *rule;
 117         int                     rulenum;
 118 };
 119
 120 unsigned int
 121 nft_do_chain(struct nft_pktinfo *pkt, void *priv)
 122 {
 123         const struct nft_chain *chain = priv, *basechain = chain;
 124         const struct net *net = pkt->net;
 125         const struct nft_rule *rule;
 126         const struct nft_expr *expr, *last;
 127         struct nft_regs regs;
 128         unsigned int stackptr = 0;
 129         struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
 130         struct nft_stats *stats;
 131         int rulenum;
 132         unsigned int gencursor = nft_genmask_cur(net);
 133         struct nft_traceinfo info;
 134
 135         info.trace = false;
 136         if (static_branch_unlikely(&nft_trace_enabled))
 137                 nft_trace_init(&info, pkt, &regs.verdict, basechain);
 138 do_chain:
 139         rulenum = 0;
 140         rule = list_entry(&chain->rules, struct nft_rule, list);
 141 next_rule:
 142         regs.verdict.code = NFT_CONTINUE;
 143         list_for_each_entry_continue_rcu(rule, &chain->rules, list) {
 144
 145                 /* This rule is not active, skip. */
 146                 if (unlikely(rule->genmask & gencursor))
 147                         continue;
 148
 149                 rulenum++;
 150
 151                 nft_rule_for_each_expr(expr, last, rule) {
 152                         if (expr->ops == &nft_cmp_fast_ops)
 153                                 nft_cmp_fast_eval(expr, &regs);
 154                         else if (expr->ops != &nft_payload_fast_ops ||
 155                                  !nft_payload_fast_eval(expr, &regs, pkt))
 156                                 expr->ops->eval(expr, &regs, pkt);
 157
 158                         if (regs.verdict.code != NFT_CONTINUE)
 159                                 break;
 160                 }
 161
 162                 switch (regs.verdict.code) {
 163                 case NFT_BREAK:
 164                         regs.verdict.code = NFT_CONTINUE;
 165                         continue;
 166                 case NFT_CONTINUE:
 167                         nft_trace_packet(&info, chain, rule,
 168                                          rulenum, NFT_TRACETYPE_RULE);
 169                         continue;
 170                 }
 171                 break;
 172         }
 173
 174         switch (regs.verdict.code & NF_VERDICT_MASK) {
 175         case NF_ACCEPT:
 176         case NF_DROP:
 177         case NF_QUEUE:
 178                 nft_trace_packet(&info, chain, rule,
 179                                  rulenum, NFT_TRACETYPE_RULE);
 180                 return regs.verdict.code;
 181         }
 182
 183         switch (regs.verdict.code) {
 184         case NFT_JUMP:
 185                 BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
 186                 jumpstack[stackptr].chain = chain;
 187                 jumpstack[stackptr].rule  = rule;
 188                 jumpstack[stackptr].rulenum = rulenum;
 189                 stackptr++;
 190                 /* fall through */
 191         case NFT_GOTO:
 192                 nft_trace_packet(&info, chain, rule,
 193                                  rulenum, NFT_TRACETYPE_RULE);
 194
 195                 chain = regs.verdict.chain;
 196                 goto do_chain;
 197         case NFT_CONTINUE:
 198                 rulenum++;
 199                 /* fall through */
 200         case NFT_RETURN:
 201                 nft_trace_packet(&info, chain, rule,
 202                                  rulenum, NFT_TRACETYPE_RETURN);
 203                 break;
 204         default:
 205                 WARN_ON(1);
 206         }
 207
 208         if (stackptr > 0) {
 209                 stackptr--;
 210                 chain = jumpstack[stackptr].chain;
 211                 rule  = jumpstack[stackptr].rule;
 212                 rulenum = jumpstack[stackptr].rulenum;
 213                 goto next_rule;
 214         }
 215
 216         nft_trace_packet(&info, basechain, NULL, -1,
 217                          NFT_TRACETYPE_POLICY);
 218
 219         rcu_read_lock_bh();
 220         stats = this_cpu_ptr(rcu_dereference(nft_base_chain(basechain)->stats));
 221         u64_stats_update_begin(&stats->syncp);
 222         stats->pkts++;
 223         stats->bytes += pkt->skb->len;
 224         u64_stats_update_end(&stats->syncp);
 225         rcu_read_unlock_bh();
 226
 227         return nft_base_chain(basechain)->policy;
 228 }
 229 EXPORT_SYMBOL_GPL(nft_do_chain);
 230
 231 int __init nf_tables_core_module_init(void)
 232 {
 233         int err;
 234
 235         err = nft_immediate_module_init();
 236         if (err < 0)
 237                 goto err1;
 238
 239         err = nft_cmp_module_init();
 240         if (err < 0)
 241                 goto err2;
 242
 243         err = nft_lookup_module_init();
 244         if (err < 0)
 245                 goto err3;
 246
 247         err = nft_bitwise_module_init();
 248         if (err < 0)
 249                 goto err4;
 250
 251         err = nft_byteorder_module_init();
 252         if (err < 0)
 253                 goto err5;
 254
 255         err = nft_payload_module_init();
 256         if (err < 0)
 257                 goto err6;
 258
 259         err = nft_dynset_module_init();
 260         if (err < 0)
 261                 goto err7;
 262
 263         return 0;
 264
 265 err7:
 266         nft_payload_module_exit();
 267 err6:
 268         nft_byteorder_module_exit();
 269 err5:
 270         nft_bitwise_module_exit();
 271 err4:
 272         nft_lookup_module_exit();
 273 err3:
 274         nft_cmp_module_exit();
 275 err2:
 276         nft_immediate_module_exit();
 277 err1:
 278         return err;
 279 }
 280
 281 void nf_tables_core_module_exit(void)
 282 {
 283         nft_dynset_module_exit();
 284         nft_payload_module_exit();
 285         nft_byteorder_module_exit();
 286         nft_bitwise_module_exit();
 287         nft_lookup_module_exit();
 288         nft_cmp_module_exit();
 289         nft_immediate_module_exit();
 290 }