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(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 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 = nft_net(pkt); 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, ®s.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, ®s); 157 else if (expr->ops != &nft_payload_fast_ops || 158 !nft_payload_fast_eval(expr, ®s, pkt)) 159 expr->ops->eval(expr, ®s, 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 case NF_STOLEN: 182 nft_trace_packet(&info, chain, rule, 183 rulenum, NFT_TRACETYPE_RULE); 184 return regs.verdict.code; 185 } 186 187 switch (regs.verdict.code) { 188 case NFT_JUMP: 189 BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE); 190 jumpstack[stackptr].chain = chain; 191 jumpstack[stackptr].rule = rule; 192 jumpstack[stackptr].rulenum = rulenum; 193 stackptr++; 194 /* fall through */ 195 case NFT_GOTO: 196 nft_trace_packet(&info, chain, rule, 197 rulenum, NFT_TRACETYPE_RULE); 198 199 chain = regs.verdict.chain; 200 goto do_chain; 201 case NFT_CONTINUE: 202 rulenum++; 203 /* fall through */ 204 case NFT_RETURN: 205 nft_trace_packet(&info, chain, rule, 206 rulenum, NFT_TRACETYPE_RETURN); 207 break; 208 default: 209 WARN_ON(1); 210 } 211 212 if (stackptr > 0) { 213 stackptr--; 214 chain = jumpstack[stackptr].chain; 215 rule = jumpstack[stackptr].rule; 216 rulenum = jumpstack[stackptr].rulenum; 217 goto next_rule; 218 } 219 220 nft_trace_packet(&info, basechain, NULL, -1, 221 NFT_TRACETYPE_POLICY); 222 223 rcu_read_lock_bh(); 224 stats = this_cpu_ptr(rcu_dereference(nft_base_chain(basechain)->stats)); 225 u64_stats_update_begin(&stats->syncp); 226 stats->pkts++; 227 stats->bytes += pkt->skb->len; 228 u64_stats_update_end(&stats->syncp); 229 rcu_read_unlock_bh(); 230 231 return nft_base_chain(basechain)->policy; 232 } 233 EXPORT_SYMBOL_GPL(nft_do_chain); 234 235 static struct nft_expr_type *nft_basic_types[] = { 236 &nft_imm_type, 237 &nft_cmp_type, 238 &nft_lookup_type, 239 &nft_bitwise_type, 240 &nft_byteorder_type, 241 &nft_payload_type, 242 &nft_dynset_type, 243 &nft_range_type, 244 }; 245 246 int __init nf_tables_core_module_init(void) 247 { 248 int err, i; 249 250 for (i = 0; i < ARRAY_SIZE(nft_basic_types); i++) { 251 err = nft_register_expr(nft_basic_types[i]); 252 if (err) 253 goto err; 254 } 255 256 return 0; 257 258 err: 259 while (i-- > 0) 260 nft_unregister_expr(nft_basic_types[i]); 261 return err; 262 } 263 264 void nf_tables_core_module_exit(void) 265 { 266 int i; 267 268 i = ARRAY_SIZE(nft_basic_types); 269 while (i-- > 0) 270 nft_unregister_expr(nft_basic_types[i]); 271 } 272