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Commit 1b2470e5 authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
Browse files

netfilter: nf_tables: handle chain name lookups via rhltable 



If there is a significant amount of chains list search is too slow, so
add an rhlist table for this.

This speeds up ruleset loading: for every new rule we have to check if
the name already exists in current generation.

We need to be able to cope with duplicate chain names in case a transaction
drops the nfnl mutex (for request_module) and the abort of this old
transaction is still pending.

The list is kept -- we need a way to iterate chains even if hash resize is
in progress without missing an entry.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 290180e2

include/net/netfilter/nf_tables.h

+6 −1
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/netfilter/x_tables.h>

#include <linux/netfilter/nf_tables.h>

#include <linux/u64_stats_sync.h>

#include <linux/rhashtable.h>

#include <net/netfilter/nf_flow_table.h>

#include <net/netlink.h>
@@ -860,6 +861,7 @@ enum nft_chain_flags { 
 *

 *	@rules: list of rules in the chain

 *	@list: used internally

 *	@rhlhead: used internally

 *	@table: table that this chain belongs to

 *	@handle: chain handle

 *	@use: number of jump references to this chain
@@ -872,6 +874,7 @@ struct nft_chain { 
	struct nft_rule			*__rcu *rules_gen_1;

	struct list_head		rules;

	struct list_head		list;

	struct rhlist_head		rhlhead;

	struct nft_table		*table;

	u64				handle;

	u32				use;
@@ -965,7 +968,8 @@ unsigned int nft_do_chain(struct nft_pktinfo *pkt, void *priv); 
 *	struct nft_table - nf_tables table

 *

 *	@list: used internally

 *	@chains: chains in the table

 *	@chains_ht: chains in the table

 *	@chains: same, for stable walks

 *	@sets: sets in the table

 *	@objects: stateful objects in the table

 *	@flowtables: flow tables in the table
@@ -979,6 +983,7 @@ unsigned int nft_do_chain(struct nft_pktinfo *pkt, void *priv); 
 */

struct nft_table {

	struct list_head		list;

	struct rhltable			chains_ht;

	struct list_head		chains;

	struct list_head		sets;

	struct list_head		objects;

net/netfilter/nf_tables_api.c

+98 −15
Original line number Diff line number Diff line
@@ -34,6 +34,20 @@ enum { 
	NFT_VALIDATE_DO,

};



static u32 nft_chain_hash(const void *data, u32 len, u32 seed);

static u32 nft_chain_hash_obj(const void *data, u32 len, u32 seed);

static int nft_chain_hash_cmp(struct rhashtable_compare_arg *, const void *);



static const struct rhashtable_params nft_chain_ht_params = {

	.head_offset		= offsetof(struct nft_chain, rhlhead),

	.key_offset		= offsetof(struct nft_chain, name),

	.hashfn			= nft_chain_hash,

	.obj_hashfn		= nft_chain_hash_obj,

	.obj_cmpfn		= nft_chain_hash_cmp,

	.locks_mul		= 1,

	.automatic_shrinking	= true,

};



static void nft_validate_state_update(struct net *net, u8 new_validate_state)

{

	switch (net->nft.validate_state) {
@@ -720,6 +734,29 @@ static int nf_tables_updtable(struct nft_ctx *ctx) 
	return ret;

}



static u32 nft_chain_hash(const void *data, u32 len, u32 seed)

{

	const char *name = data;



	return jhash(name, strlen(name), seed);

}



static u32 nft_chain_hash_obj(const void *data, u32 len, u32 seed)

{

	const struct nft_chain *chain = data;



	return nft_chain_hash(chain->name, 0, seed);

}



static int nft_chain_hash_cmp(struct rhashtable_compare_arg *arg,

			      const void *ptr)

{

	const struct nft_chain *chain = ptr;

	const char *name = arg->key;



	return strcmp(chain->name, name);

}



static int nf_tables_newtable(struct net *net, struct sock *nlsk,

			      struct sk_buff *skb, const struct nlmsghdr *nlh,

			      const struct nlattr * const nla[],
@@ -766,6 +803,10 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk, 
	if (table->name == NULL)

		goto err_strdup;



	err = rhltable_init(&table->chains_ht, &nft_chain_ht_params);

	if (err)

		goto err_chain_ht;



	INIT_LIST_HEAD(&table->chains);

	INIT_LIST_HEAD(&table->sets);

	INIT_LIST_HEAD(&table->objects);
@@ -782,6 +823,8 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk, 
	list_add_tail_rcu(&table->list, &net->nft.tables);

	return 0;

err_trans:

	rhltable_destroy(&table->chains_ht);

err_chain_ht:

	kfree(table->name);

err_strdup:

	kfree(table);
@@ -922,6 +965,7 @@ static void nf_tables_table_destroy(struct nft_ctx *ctx) 
{

	BUG_ON(ctx->table->use > 0);



	rhltable_destroy(&ctx->table->chains_ht);

	kfree(ctx->table->name);

	kfree(ctx->table);

}
@@ -967,21 +1011,35 @@ nft_chain_lookup_byhandle(const struct nft_table *table, u64 handle, u8 genmask) 
	return ERR_PTR(-ENOENT);

}



static struct nft_chain *nft_chain_lookup(const struct nft_table *table,

static struct nft_chain *nft_chain_lookup(struct nft_table *table,

					  const struct nlattr *nla, u8 genmask)

{

	char search[NFT_CHAIN_MAXNAMELEN + 1];

	struct rhlist_head *tmp, *list;

	struct nft_chain *chain;



	if (nla == NULL)

		return ERR_PTR(-EINVAL);



	list_for_each_entry_rcu(chain, &table->chains, list) {

		if (!nla_strcmp(nla, chain->name) &&

		    nft_active_genmask(chain, genmask))

			return chain;

	}

	nla_strlcpy(search, nla, sizeof(search));



	return ERR_PTR(-ENOENT);

	WARN_ON(!rcu_read_lock_held() &&

		!lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES));



	chain = ERR_PTR(-ENOENT);

	rcu_read_lock();

	list = rhltable_lookup(&table->chains_ht, search, nft_chain_ht_params);

	if (!list)

		goto out_unlock;



	rhl_for_each_entry_rcu(chain, tmp, list, rhlhead) {

		if (nft_active_genmask(chain, genmask))

			goto out_unlock;

	}

	chain = ERR_PTR(-ENOENT);

out_unlock:

	rcu_read_unlock();

	return chain;

}



static const struct nla_policy nft_chain_policy[NFTA_CHAIN_MAX + 1] = {
@@ -1185,8 +1243,8 @@ static int nf_tables_getchain(struct net *net, struct sock *nlsk, 
{

	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);

	u8 genmask = nft_genmask_cur(net);

	const struct nft_table *table;

	const struct nft_chain *chain;

	struct nft_table *table;

	struct sk_buff *skb2;

	int family = nfmsg->nfgen_family;

	int err;
@@ -1504,9 +1562,17 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, 
	if (err < 0)

		goto err1;



	err = rhltable_insert_key(&table->chains_ht, chain->name,

				  &chain->rhlhead, nft_chain_ht_params);

	if (err)

		goto err2;



	err = nft_trans_chain_add(ctx, NFT_MSG_NEWCHAIN);

	if (err < 0)

	if (err < 0) {

		rhltable_remove(&table->chains_ht, &chain->rhlhead,

				nft_chain_ht_params);

		goto err2;

	}



	table->use++;

	list_add_tail_rcu(&chain->list, &table->chains);
@@ -2206,9 +2272,9 @@ static int nf_tables_getrule(struct net *net, struct sock *nlsk, 
{

	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);

	u8 genmask = nft_genmask_cur(net);

	const struct nft_table *table;

	const struct nft_chain *chain;

	const struct nft_rule *rule;

	struct nft_table *table;

	struct sk_buff *skb2;

	int family = nfmsg->nfgen_family;

	int err;
@@ -5981,8 +6047,16 @@ static void nft_chain_commit_update(struct nft_trans *trans) 
{

	struct nft_base_chain *basechain;



	if (nft_trans_chain_name(trans))

	if (nft_trans_chain_name(trans)) {

		rhltable_remove(&trans->ctx.table->chains_ht,

				&trans->ctx.chain->rhlhead,

				nft_chain_ht_params);

		swap(trans->ctx.chain->name, nft_trans_chain_name(trans));

		rhltable_insert_key(&trans->ctx.table->chains_ht,

				    trans->ctx.chain->name,

				    &trans->ctx.chain->rhlhead,

				    nft_chain_ht_params);

	}



	if (!nft_is_base_chain(trans->ctx.chain))

		return;
@@ -6159,6 +6233,15 @@ static void nf_tables_commit_chain_active(struct net *net, struct nft_chain *cha 
		nf_tables_commit_chain_free_rules_old(g0);

}



static void nft_chain_del(struct nft_chain *chain)

{

	struct nft_table *table = chain->table;



	WARN_ON_ONCE(rhltable_remove(&table->chains_ht, &chain->rhlhead,

				     nft_chain_ht_params));

	list_del_rcu(&chain->list);

}



static int nf_tables_commit(struct net *net, struct sk_buff *skb)

{

	struct nft_trans *trans, *next;
@@ -6233,7 +6316,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb) 
			nft_trans_destroy(trans);

			break;

		case NFT_MSG_DELCHAIN:

			list_del_rcu(&trans->ctx.chain->list);

			nft_chain_del(trans->ctx.chain);

			nf_tables_chain_notify(&trans->ctx, NFT_MSG_DELCHAIN);

			nf_tables_unregister_hook(trans->ctx.net,

						  trans->ctx.table,
@@ -6384,7 +6467,7 @@ static int nf_tables_abort(struct net *net, struct sk_buff *skb) 
				nft_trans_destroy(trans);

			} else {

				trans->ctx.table->use--;

				list_del_rcu(&trans->ctx.chain->list);

				nft_chain_del(trans->ctx.chain);

				nf_tables_unregister_hook(trans->ctx.net,

							  trans->ctx.table,

							  trans->ctx.chain);
@@ -6986,7 +7069,7 @@ int __nft_release_basechain(struct nft_ctx *ctx) 
		ctx->chain->use--;

		nf_tables_rule_release(ctx, rule);

	}

	list_del(&ctx->chain->list);

	nft_chain_del(ctx->chain);

	ctx->table->use--;

	nf_tables_chain_destroy(ctx);
@@ -7042,7 +7125,7 @@ static void __nft_release_tables(struct net *net) 
		}

		list_for_each_entry_safe(chain, nc, &table->chains, list) {

			ctx.chain = chain;

			list_del(&chain->list);

			nft_chain_del(chain);

			table->use--;

			nf_tables_chain_destroy(&ctx);

		}