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 const 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(nft_net(pkt), nft_pf(pkt), nft_hook(pkt), pkt->skb, 57 nft_in(pkt), nft_out(pkt), &trace_loginfo, 58 "TRACE: %s:%s:%s:%u ", 59 chain->table->name, chain->name, comments[type], 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 = ®s->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 DEFINE_STATIC_KEY_FALSE(nft_counters_enabled); 118 119 static noinline void nft_update_chain_stats(const struct nft_chain *chain, 120 const struct nft_pktinfo *pkt) 121 { 122 struct nft_stats *stats; 123 124 local_bh_disable(); 125 stats = this_cpu_ptr(rcu_dereference(nft_base_chain(chain)->stats)); 126 u64_stats_update_begin(&stats->syncp); 127 stats->pkts++; 128 stats->bytes += pkt->skb->len; 129 u64_stats_update_end(&stats->syncp); 130 local_bh_enable(); 131 } 132 133 struct nft_jumpstack { 134 const struct nft_chain *chain; 135 const struct nft_rule *rule; 136 int rulenum; 137 }; 138 139 unsigned int 140 nft_do_chain(struct nft_pktinfo *pkt, void *priv) 141 { 142 const struct nft_chain *chain = priv, *basechain = chain; 143 const struct net *net = nft_net(pkt); 144 const struct nft_rule *rule; 145 const struct nft_expr *expr, *last; 146 struct nft_regs regs; 147 unsigned int stackptr = 0; 148 struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE]; 149 int rulenum; 150 unsigned int gencursor = nft_genmask_cur(net); 151 struct nft_traceinfo info; 152 153 info.trace = false; 154 if (static_branch_unlikely(&nft_trace_enabled)) 155 nft_trace_init(&info, pkt, ®s.verdict, basechain); 156 do_chain: 157 rulenum = 0; 158 rule = list_entry(&chain->rules, struct nft_rule, list); 159 next_rule: 160 regs.verdict.code = NFT_CONTINUE; 161 list_for_each_entry_continue_rcu(rule, &chain->rules, list) { 162 163 /* This rule is not active, skip. */ 164 if (unlikely(rule->genmask & gencursor)) 165 continue; 166 167 rulenum++; 168 169 nft_rule_for_each_expr(expr, last, rule) { 170 if (expr->ops == &nft_cmp_fast_ops) 171 nft_cmp_fast_eval(expr, ®s); 172 else if (expr->ops != &nft_payload_fast_ops || 173 !nft_payload_fast_eval(expr, ®s, pkt)) 174 expr->ops->eval(expr, ®s, pkt); 175 176 if (regs.verdict.code != NFT_CONTINUE) 177 break; 178 } 179 180 switch (regs.verdict.code) { 181 case NFT_BREAK: 182 regs.verdict.code = NFT_CONTINUE; 183 continue; 184 case NFT_CONTINUE: 185 nft_trace_packet(&info, chain, rule, 186 rulenum, NFT_TRACETYPE_RULE); 187 continue; 188 } 189 break; 190 } 191 192 switch (regs.verdict.code & NF_VERDICT_MASK) { 193 case NF_ACCEPT: 194 case NF_DROP: 195 case NF_QUEUE: 196 case NF_STOLEN: 197 nft_trace_packet(&info, chain, rule, 198 rulenum, NFT_TRACETYPE_RULE); 199 return regs.verdict.code; 200 } 201 202 switch (regs.verdict.code) { 203 case NFT_JUMP: 204 BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE); 205 jumpstack[stackptr].chain = chain; 206 jumpstack[stackptr].rule = rule; 207 jumpstack[stackptr].rulenum = rulenum; 208 stackptr++; 209 /* fall through */ 210 case NFT_GOTO: 211 nft_trace_packet(&info, chain, rule, 212 rulenum, NFT_TRACETYPE_RULE); 213 214 chain = regs.verdict.chain; 215 goto do_chain; 216 case NFT_CONTINUE: 217 rulenum++; 218 /* fall through */ 219 case NFT_RETURN: 220 nft_trace_packet(&info, chain, rule, 221 rulenum, NFT_TRACETYPE_RETURN); 222 break; 223 default: 224 WARN_ON(1); 225 } 226 227 if (stackptr > 0) { 228 stackptr--; 229 chain = jumpstack[stackptr].chain; 230 rule = jumpstack[stackptr].rule; 231 rulenum = jumpstack[stackptr].rulenum; 232 goto next_rule; 233 } 234 235 nft_trace_packet(&info, basechain, NULL, -1, 236 NFT_TRACETYPE_POLICY); 237 238 if (static_branch_unlikely(&nft_counters_enabled)) 239 nft_update_chain_stats(basechain, pkt); 240 241 return nft_base_chain(basechain)->policy; 242 } 243 EXPORT_SYMBOL_GPL(nft_do_chain); 244 245 static struct nft_expr_type *nft_basic_types[] = { 246 &nft_imm_type, 247 &nft_cmp_type, 248 &nft_lookup_type, 249 &nft_bitwise_type, 250 &nft_byteorder_type, 251 &nft_payload_type, 252 &nft_dynset_type, 253 &nft_range_type, 254 }; 255 256 int __init nf_tables_core_module_init(void) 257 { 258 int err, i; 259 260 for (i = 0; i < ARRAY_SIZE(nft_basic_types); i++) { 261 err = nft_register_expr(nft_basic_types[i]); 262 if (err) 263 goto err; 264 } 265 266 return 0; 267 268 err: 269 while (i-- > 0) 270 nft_unregister_expr(nft_basic_types[i]); 271 return err; 272 } 273 274 void nf_tables_core_module_exit(void) 275 { 276 int i; 277 278 i = ARRAY_SIZE(nft_basic_types); 279 while (i-- > 0) 280 nft_unregister_expr(nft_basic_types[i]); 281 } 282