[mirror_ubuntu-bionic-kernel.git] / net / netfilter / nf_tables_core.c

/*
 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Development of this code funded by Astaro AG (http://www.astaro.com/)
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_log.h>

static void nft_cmp_fast_eval(const struct nft_expr *expr,
			      struct nft_data data[NFT_REG_MAX + 1])
{
	const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
	u32 mask = nft_cmp_fast_mask(priv->len);

	if ((data[priv->sreg].data[0] & mask) == priv->data)
		return;
	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
}

static bool nft_payload_fast_eval(const struct nft_expr *expr,
				  struct nft_data data[NFT_REG_MAX + 1],
				  const struct nft_pktinfo *pkt)
{
	const struct nft_payload *priv = nft_expr_priv(expr);
	const struct sk_buff *skb = pkt->skb;
	struct nft_data *dest = &data[priv->dreg];
	unsigned char *ptr;

	if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
		ptr = skb_network_header(skb);
	else
		ptr = skb_network_header(skb) + pkt->xt.thoff;

	ptr += priv->offset;

	if (unlikely(ptr + priv->len >= skb_tail_pointer(skb)))
		return false;

	if (priv->len == 2)
		*(u16 *)dest->data = *(u16 *)ptr;
	else if (priv->len == 4)
		*(u32 *)dest->data = *(u32 *)ptr;
	else
		*(u8 *)dest->data = *(u8 *)ptr;
	return true;
}

struct nft_jumpstack {
	const struct nft_chain	*chain;
	const struct nft_rule	*rule;
	int			rulenum;
};

static inline void
nft_chain_stats(const struct nft_chain *this, const struct nft_pktinfo *pkt,
		struct nft_jumpstack *jumpstack, unsigned int stackptr)
{
	struct nft_stats __percpu *stats;
	const struct nft_chain *chain = stackptr ? jumpstack[0].chain : this;

	rcu_read_lock_bh();
	stats = rcu_dereference(nft_base_chain(chain)->stats);
	__this_cpu_inc(stats->pkts);
	__this_cpu_add(stats->bytes, pkt->skb->len);
	rcu_read_unlock_bh();
}

enum nft_trace {
	NFT_TRACE_RULE,
	NFT_TRACE_RETURN,
	NFT_TRACE_POLICY,
};

static const char *const comments[] = {
	[NFT_TRACE_RULE]	= "rule",
	[NFT_TRACE_RETURN]	= "return",
	[NFT_TRACE_POLICY]	= "policy",
};

static struct nf_loginfo trace_loginfo = {
	.type = NF_LOG_TYPE_LOG,
	.u = {
		.log = {
			.level = 4,
			.logflags = NF_LOG_MASK,
	        },
	},
};

static void nft_trace_packet(const struct nft_pktinfo *pkt,
			     const struct nft_chain *chain,
			     int rulenum, enum nft_trace type)
{
	struct net *net = dev_net(pkt->in ? pkt->in : pkt->out);

	nf_log_packet(net, pkt->xt.family, pkt->ops->hooknum, pkt->skb, pkt->in,
		      pkt->out, &trace_loginfo, "TRACE: %s:%s:%s:%u ",
		      chain->table->name, chain->name, comments[type],
		      rulenum);
}

unsigned int
nft_do_chain(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
{
	const struct nft_chain *chain = ops->priv;
	const struct nft_rule *rule;
	const struct nft_expr *expr, *last;
	struct nft_data data[NFT_REG_MAX + 1];
	unsigned int stackptr = 0;
	struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
	int rulenum = 0;
	/*
	 * Cache cursor to avoid problems in case that the cursor is updated
	 * while traversing the ruleset.
	 */
	unsigned int gencursor = ACCESS_ONCE(chain->net->nft.gencursor);

do_chain:
	rule = list_entry(&chain->rules, struct nft_rule, list);
next_rule:
	data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
	list_for_each_entry_continue_rcu(rule, &chain->rules, list) {

		/* This rule is not active, skip. */
		if (unlikely(rule->genmask & (1 << gencursor)))
			continue;

		rulenum++;

		nft_rule_for_each_expr(expr, last, rule) {
			if (expr->ops == &nft_cmp_fast_ops)
				nft_cmp_fast_eval(expr, data);
			else if (expr->ops != &nft_payload_fast_ops ||
				 !nft_payload_fast_eval(expr, data, pkt))
				expr->ops->eval(expr, data, pkt);

			if (data[NFT_REG_VERDICT].verdict != NFT_CONTINUE)
				break;
		}

		switch (data[NFT_REG_VERDICT].verdict) {
		case NFT_BREAK:
			data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
			/* fall through */
		case NFT_CONTINUE:
			continue;
		}
		break;
	}

	switch (data[NFT_REG_VERDICT].verdict & NF_VERDICT_MASK) {
	case NF_ACCEPT:
	case NF_DROP:
	case NF_QUEUE:
		if (unlikely(pkt->skb->nf_trace))
			nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);

		return data[NFT_REG_VERDICT].verdict;
	}

	switch (data[NFT_REG_VERDICT].verdict) {
	case NFT_JUMP:
		if (unlikely(pkt->skb->nf_trace))
			nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);

		BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
		jumpstack[stackptr].chain = chain;
		jumpstack[stackptr].rule  = rule;
		jumpstack[stackptr].rulenum = rulenum;
		stackptr++;
		/* fall through */
	case NFT_GOTO:
		chain = data[NFT_REG_VERDICT].chain;
		goto do_chain;
	case NFT_RETURN:
		if (unlikely(pkt->skb->nf_trace))
			nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RETURN);

		/* fall through */
	case NFT_CONTINUE:
		break;
	default:
		WARN_ON(1);
	}

	if (stackptr > 0) {
		if (unlikely(pkt->skb->nf_trace))
			nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_RETURN);

		stackptr--;
		chain = jumpstack[stackptr].chain;
		rule  = jumpstack[stackptr].rule;
		rulenum = jumpstack[stackptr].rulenum;
		goto next_rule;
	}
	nft_chain_stats(chain, pkt, jumpstack, stackptr);

	if (unlikely(pkt->skb->nf_trace))
		nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_POLICY);

	return nft_base_chain(chain)->policy;
}
EXPORT_SYMBOL_GPL(nft_do_chain);

int __init nf_tables_core_module_init(void)
{
	int err;

	err = nft_immediate_module_init();
	if (err < 0)
		goto err1;

	err = nft_cmp_module_init();
	if (err < 0)
		goto err2;

	err = nft_lookup_module_init();
	if (err < 0)
		goto err3;

	err = nft_bitwise_module_init();
	if (err < 0)
		goto err4;

	err = nft_byteorder_module_init();
	if (err < 0)
		goto err5;

	err = nft_payload_module_init();
	if (err < 0)
		goto err6;

	return 0;

err6:
	nft_byteorder_module_exit();
err5:
	nft_bitwise_module_exit();
err4:
	nft_lookup_module_exit();
err3:
	nft_cmp_module_exit();
err2:
	nft_immediate_module_exit();
err1:
	return err;
}

void nf_tables_core_module_exit(void)
{
	nft_payload_module_exit();
	nft_byteorder_module_exit();
	nft_bitwise_module_exit();
	nft_lookup_module_exit();
	nft_cmp_module_exit();
	nft_immediate_module_exit();
}
Commit	Line	Data
96518518 PM	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/module.h>
	12	#include <linux/init.h>
	13	#include <linux/list.h>
	14	#include <linux/rculist.h>
	15	#include <linux/skbuff.h>
	16	#include <linux/netlink.h>
	17	#include <linux/netfilter.h>
	18	#include <linux/netfilter/nfnetlink.h>
	19	#include <linux/netfilter/nf_tables.h>
	20	#include <net/netfilter/nf_tables_core.h>
	21	#include <net/netfilter/nf_tables.h>
b5bc89bf	22	#include <net/netfilter/nf_log.h>
96518518	23
cb7dbfd0 PM	24	static void nft_cmp_fast_eval(const struct nft_expr *expr,
	25	struct nft_data data[NFT_REG_MAX + 1])
	26	{
	27	const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
b855d416	28	u32 mask = nft_cmp_fast_mask(priv->len);
cb7dbfd0	29
cb7dbfd0 PM	30	if ((data[priv->sreg].data[0] & mask) == priv->data)
	31	return;
	32	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
	33	}
	34
c29b72e0 PM	35	static bool nft_payload_fast_eval(const struct nft_expr *expr,
	36	struct nft_data data[NFT_REG_MAX + 1],
	37	const struct nft_pktinfo *pkt)
	38	{
	39	const struct nft_payload *priv = nft_expr_priv(expr);
	40	const struct sk_buff *skb = pkt->skb;
	41	struct nft_data *dest = &data[priv->dreg];
	42	unsigned char *ptr;
	43
	44	if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
	45	ptr = skb_network_header(skb);
	46	else
c54032e0	47	ptr = skb_network_header(skb) + pkt->xt.thoff;
c29b72e0 PM	48
	49	ptr += priv->offset;
	50
	51	if (unlikely(ptr + priv->len >= skb_tail_pointer(skb)))
	52	return false;
	53
	54	if (priv->len == 2)
	55	(u16 )dest->data = (u16 )ptr;
	56	else if (priv->len == 4)
	57	(u32 )dest->data = (u32 )ptr;
	58	else
	59	(u8 )dest->data = (u8 )ptr;
	60	return true;
	61	}
	62
0ca743a5 PNA	63	struct nft_jumpstack {
	64	const struct nft_chain *chain;
	65	const struct nft_rule *rule;
b5bc89bf	66	int rulenum;
0ca743a5 PNA	67	};
	68
	69	static inline void
	70	nft_chain_stats(const struct nft_chain this, const struct nft_pktinfo pkt,
	71	struct nft_jumpstack *jumpstack, unsigned int stackptr)
	72	{
	73	struct nft_stats __percpu *stats;
	74	const struct nft_chain *chain = stackptr ? jumpstack[0].chain : this;
	75
	76	rcu_read_lock_bh();
	77	stats = rcu_dereference(nft_base_chain(chain)->stats);
	78	__this_cpu_inc(stats->pkts);
	79	__this_cpu_add(stats->bytes, pkt->skb->len);
	80	rcu_read_unlock_bh();
	81	}
	82
b5bc89bf PNA	83	enum nft_trace {
	84	NFT_TRACE_RULE,
	85	NFT_TRACE_RETURN,
	86	NFT_TRACE_POLICY,
	87	};
	88
	89	static const char *const comments[] = {
	90	[NFT_TRACE_RULE] = "rule",
	91	[NFT_TRACE_RETURN] = "return",
	92	[NFT_TRACE_POLICY] = "policy",
	93	};
	94
	95	static struct nf_loginfo trace_loginfo = {
	96	.type = NF_LOG_TYPE_LOG,
	97	.u = {
	98	.log = {
	99	.level = 4,
	100	.logflags = NF_LOG_MASK,
	101	},
	102	},
	103	};
	104
6d8c00d5 PM	105	static void nft_trace_packet(const struct nft_pktinfo *pkt,
	106	const struct nft_chain *chain,
	107	int rulenum, enum nft_trace type)
b5bc89bf PNA	108	{
	109	struct net *net = dev_net(pkt->in ? pkt->in : pkt->out);
	110
c9484874	111	nf_log_packet(net, pkt->xt.family, pkt->ops->hooknum, pkt->skb, pkt->in,
b5bc89bf PNA	112	pkt->out, &trace_loginfo, "TRACE: %s:%s:%s:%u ",
	113	chain->table->name, chain->name, comments[type],
	114	rulenum);
	115	}
	116
0ca743a5	117	unsigned int
3876d22d	118	nft_do_chain(struct nft_pktinfo pkt, const struct nf_hook_ops ops)
96518518 PM	119	{
	120	const struct nft_chain *chain = ops->priv;
	121	const struct nft_rule *rule;
	122	const struct nft_expr expr, last;
	123	struct nft_data data[NFT_REG_MAX + 1];
96518518	124	unsigned int stackptr = 0;
0ca743a5	125	struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
b5bc89bf	126	int rulenum = 0;
0628b123 PNA	127	/*
	128	* Cache cursor to avoid problems in case that the cursor is updated
	129	* while traversing the ruleset.
	130	*/
	131	unsigned int gencursor = ACCESS_ONCE(chain->net->nft.gencursor);
96518518 PM	132
	133	do_chain:
	134	rule = list_entry(&chain->rules, struct nft_rule, list);
	135	next_rule:
	136	data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
	137	list_for_each_entry_continue_rcu(rule, &chain->rules, list) {
0628b123 PNA	138
	139	/* This rule is not active, skip. */
	140	if (unlikely(rule->genmask & (1 << gencursor)))
	141	continue;
	142
b5bc89bf PNA	143	rulenum++;
b5bc89bf PNA	144
96518518	145	nft_rule_for_each_expr(expr, last, rule) {
cb7dbfd0 PM	146	if (expr->ops == &nft_cmp_fast_ops)
cb7dbfd0 PM	147	nft_cmp_fast_eval(expr, data);
c29b72e0	148	else if (expr->ops != &nft_payload_fast_ops \|\|
0ca743a5 PNA	149	!nft_payload_fast_eval(expr, data, pkt))
0ca743a5 PNA	150	expr->ops->eval(expr, data, pkt);
cb7dbfd0	151
96518518 PM	152	if (data[NFT_REG_VERDICT].verdict != NFT_CONTINUE)
	153	break;
	154	}
	155
	156	switch (data[NFT_REG_VERDICT].verdict) {
	157	case NFT_BREAK:
	158	data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
	159	/* fall through */
	160	case NFT_CONTINUE:
	161	continue;
	162	}
	163	break;
	164	}
	165
e569bdab	166	switch (data[NFT_REG_VERDICT].verdict & NF_VERDICT_MASK) {
96518518 PM	167	case NF_ACCEPT:
	168	case NF_DROP:
	169	case NF_QUEUE:
b5bc89bf PNA	170	if (unlikely(pkt->skb->nf_trace))
	171	nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
	172
96518518	173	return data[NFT_REG_VERDICT].verdict;
e569bdab EL	174	}
	175
	176	switch (data[NFT_REG_VERDICT].verdict) {
96518518	177	case NFT_JUMP:
b5bc89bf PNA	178	if (unlikely(pkt->skb->nf_trace))
	179	nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
	180
96518518 PM	181	BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
	182	jumpstack[stackptr].chain = chain;
	183	jumpstack[stackptr].rule = rule;
b5bc89bf	184	jumpstack[stackptr].rulenum = rulenum;
96518518 PM	185	stackptr++;
	186	/* fall through */
	187	case NFT_GOTO:
	188	chain = data[NFT_REG_VERDICT].chain;
	189	goto do_chain;
	190	case NFT_RETURN:
b5bc89bf PNA	191	if (unlikely(pkt->skb->nf_trace))
	192	nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RETURN);
	193
	194	/* fall through */
96518518 PM	195	case NFT_CONTINUE:
	196	break;
	197	default:
	198	WARN_ON(1);
	199	}
	200
	201	if (stackptr > 0) {
b5bc89bf PNA	202	if (unlikely(pkt->skb->nf_trace))
	203	nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_RETURN);
	204
96518518 PM	205	stackptr--;
	206	chain = jumpstack[stackptr].chain;
	207	rule = jumpstack[stackptr].rule;
b5bc89bf	208	rulenum = jumpstack[stackptr].rulenum;
96518518 PM	209	goto next_rule;
96518518 PM	210	}
0ca743a5	211	nft_chain_stats(chain, pkt, jumpstack, stackptr);
96518518	212
b5bc89bf PNA	213	if (unlikely(pkt->skb->nf_trace))
	214	nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_POLICY);
	215
0ca743a5	216	return nft_base_chain(chain)->policy;
96518518	217	}
3876d22d	218	EXPORT_SYMBOL_GPL(nft_do_chain);
96518518 PM	219
	220	int __init nf_tables_core_module_init(void)
	221	{
	222	int err;
	223
	224	err = nft_immediate_module_init();
	225	if (err < 0)
	226	goto err1;
	227
	228	err = nft_cmp_module_init();
	229	if (err < 0)
	230	goto err2;
	231
	232	err = nft_lookup_module_init();
	233	if (err < 0)
	234	goto err3;
	235
	236	err = nft_bitwise_module_init();
	237	if (err < 0)
	238	goto err4;
	239
	240	err = nft_byteorder_module_init();
	241	if (err < 0)
	242	goto err5;
	243
	244	err = nft_payload_module_init();
	245	if (err < 0)
	246	goto err6;
	247
	248	return 0;
	249
	250	err6:
	251	nft_byteorder_module_exit();
	252	err5:
	253	nft_bitwise_module_exit();
	254	err4:
	255	nft_lookup_module_exit();
	256	err3:
	257	nft_cmp_module_exit();
	258	err2:
	259	nft_immediate_module_exit();
	260	err1:
	261	return err;
	262	}
	263
	264	void nf_tables_core_module_exit(void)
	265	{
	266	nft_payload_module_exit();
	267	nft_byteorder_module_exit();
	268	nft_bitwise_module_exit();
	269	nft_lookup_module_exit();
	270	nft_cmp_module_exit();
	271	nft_immediate_module_exit();
	272	}