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netfilter: nf_tables: Speed up selective rule dumps 

If just a table name was given, nf_tables_dump_rules() continued over
the list of tables even after a match was found. The simple fix is to
exit the loop if it reached the bottom and ctx->table was not NULL.

When iterating over the table's chains, the same problem as above
existed. But worse than that, if a chain name was given the hash table
wasn't used to find the corresponding chain. Fix this by introducing a
helper function iterating over a chain's rules (and taking care of the
cb->args handling), then introduce a shortcut to it if a chain name was
given.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Phil Sutter 2018-12-12 19:29:07 +01:00 committed by Pablo Neira Ayuso
parent 8294059931
commit 241faeceb8
1 changed files with 61 additions and 27 deletions
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88
net/netfilter/nf_tables_api.c
View File

@ -2291,15 +2291,52 @@ struct nft_rule_dump_ctx {
char *chain;
};
static int __nf_tables_dump_rules(struct sk_buff *skb,
unsigned int *idx,
struct netlink_callback *cb,
const struct nft_table *table,
const struct nft_chain *chain)
{
struct net *net = sock_net(skb->sk);
unsigned int s_idx = cb->args[0];
const struct nft_rule *rule;
int rc = 1;
list_for_each_entry_rcu(rule, &chain->rules, list) {
if (!nft_is_active(net, rule))
goto cont;
if (*idx < s_idx)
goto cont;
if (*idx > s_idx) {
memset(&cb->args[1], 0,
sizeof(cb->args) - sizeof(cb->args[0]));
}
if (nf_tables_fill_rule_info(skb, net, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NFT_MSG_NEWRULE,
NLM_F_MULTI | NLM_F_APPEND,
table->family,
table, chain, rule) < 0)
goto out_unfinished;
nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
(*idx)++;
}
rc = 0;
out_unfinished:
cb->args[0] = *idx;
return rc;
}
static int nf_tables_dump_rules(struct sk_buff *skb,
struct netlink_callback *cb)
{
const struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
const struct nft_rule_dump_ctx *ctx = cb->data;
const struct nft_table *table;
struct nft_table *table;
const struct nft_chain *chain;
const struct nft_rule *rule;
unsigned int idx = 0, s_idx = cb->args[0];
unsigned int idx = 0;
struct net *net = sock_net(skb->sk);
int family = nfmsg->nfgen_family;
@ -2313,37 +2350,34 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
if (ctx && ctx->table && strcmp(ctx->table, table->name) != 0)
continue;
list_for_each_entry_rcu(chain, &table->chains, list) {
if (ctx && ctx->chain &&
strcmp(ctx->chain, chain->name) != 0)
continue;
if (ctx && ctx->chain) {
struct rhlist_head *list, *tmp;
list_for_each_entry_rcu(rule, &chain->rules, list) {
if (!nft_is_active(net, rule))
goto cont;
if (idx < s_idx)
goto cont;
if (idx > s_idx)
memset(&cb->args[1], 0,
sizeof(cb->args) - sizeof(cb->args[0]));
if (nf_tables_fill_rule_info(skb, net, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NFT_MSG_NEWRULE,
NLM_F_MULTI | NLM_F_APPEND,
table->family,
table, chain, rule) < 0)
goto done;
list = rhltable_lookup(&table->chains_ht, ctx->chain,
nft_chain_ht_params);
if (!list)
goto done;
nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
idx++;
rhl_for_each_entry_rcu(chain, tmp, list, rhlhead) {
if (!nft_is_active(net, chain))
continue;
__nf_tables_dump_rules(skb, &idx,
cb, table, chain);
break;
}
goto done;
}
list_for_each_entry_rcu(chain, &table->chains, list) {
if (__nf_tables_dump_rules(skb, &idx, cb, table, chain))
goto done;
}
if (ctx && ctx->table)
break;
}
done:
rcu_read_unlock();
cb->args[0] = idx;
return skb->len;
}