netfilter: nf_tables: Introduce nf_tables_getrule_single()

Outsource the reply skb preparation for non-dump getrule requests into a
distinct function. Prep work for rule reset locking.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Phil Sutter 2023-10-19 16:03:35 +02:00 committed by Pablo Neira Ayuso
parent 8877393029
commit 1578c32877

View File

@ -3586,22 +3586,62 @@ static int nf_tables_dump_rules_done(struct netlink_callback *cb)
}
/* called with rcu_read_lock held */
static int nf_tables_getrule(struct sk_buff *skb, const struct nfnl_info *info,
const struct nlattr * const nla[])
static struct sk_buff *
nf_tables_getrule_single(u32 portid, const struct nfnl_info *info,
const struct nlattr * const nla[], bool reset)
{
struct nftables_pernet *nft_net = nft_pernet(info->net);
struct netlink_ext_ack *extack = info->extack;
u8 genmask = nft_genmask_cur(info->net);
u8 family = info->nfmsg->nfgen_family;
u32 portid = NETLINK_CB(skb).portid;
const struct nft_chain *chain;
const struct nft_rule *rule;
struct net *net = info->net;
struct nft_table *table;
struct sk_buff *skb2;
int err;
table = nft_table_lookup(net, nla[NFTA_RULE_TABLE], family, genmask, 0);
if (IS_ERR(table)) {
NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_TABLE]);
return ERR_CAST(table);
}
chain = nft_chain_lookup(net, table, nla[NFTA_RULE_CHAIN], genmask);
if (IS_ERR(chain)) {
NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_CHAIN]);
return ERR_CAST(chain);
}
rule = nft_rule_lookup(chain, nla[NFTA_RULE_HANDLE]);
if (IS_ERR(rule)) {
NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_HANDLE]);
return ERR_CAST(rule);
}
skb2 = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
if (!skb2)
return ERR_PTR(-ENOMEM);
err = nf_tables_fill_rule_info(skb2, net, portid,
info->nlh->nlmsg_seq, NFT_MSG_NEWRULE, 0,
family, table, chain, rule, 0, reset);
if (err < 0) {
kfree_skb(skb2);
return ERR_PTR(err);
}
return skb2;
}
static int nf_tables_getrule(struct sk_buff *skb, const struct nfnl_info *info,
const struct nlattr * const nla[])
{
struct nftables_pernet *nft_net = nft_pernet(info->net);
u32 portid = NETLINK_CB(skb).portid;
struct net *net = info->net;
struct sk_buff *skb2;
bool reset = false;
char *buf;
int err;
if (info->nlh->nlmsg_flags & NLM_F_DUMP) {
struct netlink_dump_control c = {
@ -3615,36 +3655,12 @@ static int nf_tables_getrule(struct sk_buff *skb, const struct nfnl_info *info,
return nft_netlink_dump_start_rcu(info->sk, skb, info->nlh, &c);
}
table = nft_table_lookup(net, nla[NFTA_RULE_TABLE], family, genmask, 0);
if (IS_ERR(table)) {
NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_TABLE]);
return PTR_ERR(table);
}
chain = nft_chain_lookup(net, table, nla[NFTA_RULE_CHAIN], genmask);
if (IS_ERR(chain)) {
NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_CHAIN]);
return PTR_ERR(chain);
}
rule = nft_rule_lookup(chain, nla[NFTA_RULE_HANDLE]);
if (IS_ERR(rule)) {
NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_HANDLE]);
return PTR_ERR(rule);
}
skb2 = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
if (!skb2)
return -ENOMEM;
if (NFNL_MSG_TYPE(info->nlh->nlmsg_type) == NFT_MSG_GETRULE_RESET)
reset = true;
err = nf_tables_fill_rule_info(skb2, net, portid,
info->nlh->nlmsg_seq, NFT_MSG_NEWRULE, 0,
family, table, chain, rule, 0, reset);
if (err < 0)
goto err_fill_rule_info;
skb2 = nf_tables_getrule_single(portid, info, nla, reset);
if (IS_ERR(skb2))
return PTR_ERR(skb2);
if (!reset)
return nfnetlink_unicast(skb2, net, portid);
@ -3658,10 +3674,6 @@ static int nf_tables_getrule(struct sk_buff *skb, const struct nfnl_info *info,
kfree(buf);
return nfnetlink_unicast(skb2, net, portid);
err_fill_rule_info:
kfree_skb(skb2);
return err;
}
void nf_tables_rule_destroy(const struct nft_ctx *ctx, struct nft_rule *rule)