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
__nft_trace_packet(struct nft_traceinfo * info,const struct nft_chain * chain,int rulenum,enum nft_trace_types type)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
nft_trace_packet(struct nft_traceinfo * info,const struct nft_chain * chain,const struct nft_rule * rule,int rulenum,enum nft_trace_types type)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
nft_cmp_fast_eval(const struct nft_expr * expr,struct nft_regs * regs)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
nft_payload_fast_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)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
nft_update_chain_stats(const struct nft_chain * chain,const struct nft_pktinfo * pkt)119 static noinline void nft_update_chain_stats(const struct nft_chain *chain,
120 const struct nft_pktinfo *pkt)
121 {
122 struct nft_base_chain *base_chain;
123 struct nft_stats *stats;
124
125 base_chain = nft_base_chain(chain);
126 if (!base_chain->stats)
127 return;
128
129 local_bh_disable();
130 stats = this_cpu_ptr(rcu_dereference(base_chain->stats));
131 if (stats) {
132 u64_stats_update_begin(&stats->syncp);
133 stats->pkts++;
134 stats->bytes += pkt->skb->len;
135 u64_stats_update_end(&stats->syncp);
136 }
137 local_bh_enable();
138 }
139
140 struct nft_jumpstack {
141 const struct nft_chain *chain;
142 const struct nft_rule *rule;
143 int rulenum;
144 };
145
146 unsigned int
nft_do_chain(struct nft_pktinfo * pkt,void * priv)147 nft_do_chain(struct nft_pktinfo *pkt, void *priv)
148 {
149 const struct nft_chain *chain = priv, *basechain = chain;
150 const struct net *net = nft_net(pkt);
151 const struct nft_rule *rule;
152 const struct nft_expr *expr, *last;
153 struct nft_regs regs;
154 unsigned int stackptr = 0;
155 struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
156 int rulenum;
157 unsigned int gencursor = nft_genmask_cur(net);
158 struct nft_traceinfo info;
159
160 info.trace = false;
161 if (static_branch_unlikely(&nft_trace_enabled))
162 nft_trace_init(&info, pkt, ®s.verdict, basechain);
163 do_chain:
164 rulenum = 0;
165 rule = list_entry(&chain->rules, struct nft_rule, list);
166 next_rule:
167 regs.verdict.code = NFT_CONTINUE;
168 list_for_each_entry_continue_rcu(rule, &chain->rules, list) {
169
170 /* This rule is not active, skip. */
171 if (unlikely(rule->genmask & gencursor))
172 continue;
173
174 rulenum++;
175
176 nft_rule_for_each_expr(expr, last, rule) {
177 if (expr->ops == &nft_cmp_fast_ops)
178 nft_cmp_fast_eval(expr, ®s);
179 else if (expr->ops != &nft_payload_fast_ops ||
180 !nft_payload_fast_eval(expr, ®s, pkt))
181 expr->ops->eval(expr, ®s, pkt);
182
183 if (regs.verdict.code != NFT_CONTINUE)
184 break;
185 }
186
187 switch (regs.verdict.code) {
188 case NFT_BREAK:
189 regs.verdict.code = NFT_CONTINUE;
190 continue;
191 case NFT_CONTINUE:
192 nft_trace_packet(&info, chain, rule,
193 rulenum, NFT_TRACETYPE_RULE);
194 continue;
195 }
196 break;
197 }
198
199 switch (regs.verdict.code & NF_VERDICT_MASK) {
200 case NF_ACCEPT:
201 case NF_DROP:
202 case NF_QUEUE:
203 case NF_STOLEN:
204 nft_trace_packet(&info, chain, rule,
205 rulenum, NFT_TRACETYPE_RULE);
206 return regs.verdict.code;
207 }
208
209 switch (regs.verdict.code) {
210 case NFT_JUMP:
211 if (WARN_ON_ONCE(stackptr >= NFT_JUMP_STACK_SIZE))
212 return NF_DROP;
213 jumpstack[stackptr].chain = chain;
214 jumpstack[stackptr].rule = rule;
215 jumpstack[stackptr].rulenum = rulenum;
216 stackptr++;
217 /* fall through */
218 case NFT_GOTO:
219 nft_trace_packet(&info, chain, rule,
220 rulenum, NFT_TRACETYPE_RULE);
221
222 chain = regs.verdict.chain;
223 goto do_chain;
224 case NFT_CONTINUE:
225 rulenum++;
226 /* fall through */
227 case NFT_RETURN:
228 nft_trace_packet(&info, chain, rule,
229 rulenum, NFT_TRACETYPE_RETURN);
230 break;
231 default:
232 WARN_ON(1);
233 }
234
235 if (stackptr > 0) {
236 stackptr--;
237 chain = jumpstack[stackptr].chain;
238 rule = jumpstack[stackptr].rule;
239 rulenum = jumpstack[stackptr].rulenum;
240 goto next_rule;
241 }
242
243 nft_trace_packet(&info, basechain, NULL, -1,
244 NFT_TRACETYPE_POLICY);
245
246 if (static_branch_unlikely(&nft_counters_enabled))
247 nft_update_chain_stats(basechain, pkt);
248
249 return nft_base_chain(basechain)->policy;
250 }
251 EXPORT_SYMBOL_GPL(nft_do_chain);
252
253 static struct nft_expr_type *nft_basic_types[] = {
254 &nft_imm_type,
255 &nft_cmp_type,
256 &nft_lookup_type,
257 &nft_bitwise_type,
258 &nft_byteorder_type,
259 &nft_payload_type,
260 &nft_dynset_type,
261 &nft_range_type,
262 };
263
nf_tables_core_module_init(void)264 int __init nf_tables_core_module_init(void)
265 {
266 int err, i;
267
268 for (i = 0; i < ARRAY_SIZE(nft_basic_types); i++) {
269 err = nft_register_expr(nft_basic_types[i]);
270 if (err)
271 goto err;
272 }
273
274 return 0;
275
276 err:
277 while (i-- > 0)
278 nft_unregister_expr(nft_basic_types[i]);
279 return err;
280 }
281
nf_tables_core_module_exit(void)282 void nf_tables_core_module_exit(void)
283 {
284 int i;
285
286 i = ARRAY_SIZE(nft_basic_types);
287 while (i-- > 0)
288 nft_unregister_expr(nft_basic_types[i]);
289 }
290