netfilter: nf_tables: remove nft_ctx_init_from_elemattr()

Replace nft_ctx_init_from_elemattr() by nft_table_lookup() and set up
the context structure right before it is really needed.

Moreover, nft_ctx_init_from_elemattr() is setting up the context
structure for codepaths where this is not really needed at all.

This helper function is also not helping to consolidate code, removing
it saves us 4 LoC.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_api.c

@@ -4703,28 +4703,6 @@ static const struct nla_policy nft_set_elem_list_policy[NFTA_SET_ELEM_LIST_MAX +
 	[NFTA_SET_ELEM_LIST_SET_ID]	= { .type = NLA_U32 },
 };
 
-static int nft_ctx_init_from_elemattr(struct nft_ctx *ctx, struct net *net,
-				      const struct sk_buff *skb,
-				      const struct nlmsghdr *nlh,
-				      const struct nlattr * const nla[],
-				      struct netlink_ext_ack *extack,
-				      u8 genmask, u32 nlpid)
-{
-	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
-	int family = nfmsg->nfgen_family;
-	struct nft_table *table;
-
-	table = nft_table_lookup(net, nla[NFTA_SET_ELEM_LIST_TABLE], family,
-				 genmask, nlpid);
-	if (IS_ERR(table)) {
-		NL_SET_BAD_ATTR(extack, nla[NFTA_SET_ELEM_LIST_TABLE]);
-		return PTR_ERR(table);
-	}
-
-	nft_ctx_init(ctx, net, skb, nlh, family, table, NULL, nla);
-	return 0;
-}
-
 static int nft_set_elem_expr_dump(struct sk_buff *skb,
 				  const struct nft_set *set,
 				  const struct nft_set_ext *ext)
@@ -5182,21 +5160,27 @@ static int nf_tables_getsetelem(struct sk_buff *skb,
 {
 	struct netlink_ext_ack *extack = info->extack;
 	u8 genmask = nft_genmask_cur(info->net);
+	u8 family = info->nfmsg->nfgen_family;
 	struct net *net = info->net;
+	struct nft_table *table;
 	struct nft_set *set;
 	struct nlattr *attr;
 	struct nft_ctx ctx;
 	int rem, err = 0;
 
-	err = nft_ctx_init_from_elemattr(&ctx, net, skb, info->nlh, nla, extack,
-					 genmask, NETLINK_CB(skb).portid);
-	if (err < 0)
-		return err;
+	table = nft_table_lookup(net, nla[NFTA_SET_ELEM_LIST_TABLE], family,
+				 genmask, NETLINK_CB(skb).portid);
+	if (IS_ERR(table)) {
+		NL_SET_BAD_ATTR(extack, nla[NFTA_SET_ELEM_LIST_TABLE]);
+		return PTR_ERR(table);
+	}
 
-	set = nft_set_lookup(ctx.table, nla[NFTA_SET_ELEM_LIST_SET], genmask);
+	set = nft_set_lookup(table, nla[NFTA_SET_ELEM_LIST_SET], genmask);
 	if (IS_ERR(set))
 		return PTR_ERR(set);
 
+	nft_ctx_init(&ctx, net, skb, info->nlh, family, table, NULL, nla);
+
 	if (info->nlh->nlmsg_flags & NLM_F_DUMP) {
 		struct netlink_dump_control c = {
 			.start = nf_tables_dump_set_start,
@@ -5965,8 +5949,10 @@ static int nf_tables_newsetelem(struct sk_buff *skb,
 	struct nftables_pernet *nft_net = nft_pernet(info->net);
 	struct netlink_ext_ack *extack = info->extack;
 	u8 genmask = nft_genmask_next(info->net);
+	u8 family = info->nfmsg->nfgen_family;
 	struct net *net = info->net;
 	const struct nlattr *attr;
+	struct nft_table *table;
 	struct nft_set *set;
 	struct nft_ctx ctx;
 	int rem, err;
@@ -5974,12 +5960,14 @@ static int nf_tables_newsetelem(struct sk_buff *skb,
 	if (nla[NFTA_SET_ELEM_LIST_ELEMENTS] == NULL)
 		return -EINVAL;
 
-	err = nft_ctx_init_from_elemattr(&ctx, net, skb, info->nlh, nla, extack,
-					 genmask, NETLINK_CB(skb).portid);
-	if (err < 0)
-		return err;
+	table = nft_table_lookup(net, nla[NFTA_SET_ELEM_LIST_TABLE], family,
+				 genmask, NETLINK_CB(skb).portid);
+	if (IS_ERR(table)) {
+		NL_SET_BAD_ATTR(extack, nla[NFTA_SET_ELEM_LIST_TABLE]);
+		return PTR_ERR(table);
+	}
 
-	set = nft_set_lookup_global(net, ctx.table, nla[NFTA_SET_ELEM_LIST_SET],
+	set = nft_set_lookup_global(net, table, nla[NFTA_SET_ELEM_LIST_SET],
 				    nla[NFTA_SET_ELEM_LIST_SET_ID], genmask);
 	if (IS_ERR(set))
 		return PTR_ERR(set);
@@ -5987,6 +5975,8 @@ static int nf_tables_newsetelem(struct sk_buff *skb,
 	if (!list_empty(&set->bindings) && set->flags & NFT_SET_CONSTANT)
 		return -EBUSY;
 
+	nft_ctx_init(&ctx, net, skb, info->nlh, family, table, NULL, nla);
+
 	nla_for_each_nested(attr, nla[NFTA_SET_ELEM_LIST_ELEMENTS], rem) {
 		err = nft_add_set_elem(&ctx, set, attr, info->nlh->nlmsg_flags);
 		if (err < 0)
@@ -5994,7 +5984,7 @@ static int nf_tables_newsetelem(struct sk_buff *skb,
 	}
 
 	if (nft_net->validate_state == NFT_VALIDATE_DO)
-		return nft_table_validate(net, ctx.table);
+		return nft_table_validate(net, table);
 
 	return 0;
 }
@@ -6232,23 +6222,29 @@ static int nf_tables_delsetelem(struct sk_buff *skb,
 {
 	struct netlink_ext_ack *extack = info->extack;
 	u8 genmask = nft_genmask_next(info->net);
+	u8 family = info->nfmsg->nfgen_family;
 	struct net *net = info->net;
 	const struct nlattr *attr;
+	struct nft_table *table;
 	struct nft_set *set;
 	struct nft_ctx ctx;
 	int rem, err = 0;
 
-	err = nft_ctx_init_from_elemattr(&ctx, net, skb, info->nlh, nla, extack,
-					 genmask, NETLINK_CB(skb).portid);
-	if (err < 0)
-		return err;
+	table = nft_table_lookup(net, nla[NFTA_SET_ELEM_LIST_TABLE], family,
+				 genmask, NETLINK_CB(skb).portid);
+	if (IS_ERR(table)) {
+		NL_SET_BAD_ATTR(extack, nla[NFTA_SET_ELEM_LIST_TABLE]);
+		return PTR_ERR(table);
+	}
 
-	set = nft_set_lookup(ctx.table, nla[NFTA_SET_ELEM_LIST_SET], genmask);
+	set = nft_set_lookup(table, nla[NFTA_SET_ELEM_LIST_SET], genmask);
 	if (IS_ERR(set))
 		return PTR_ERR(set);
 	if (!list_empty(&set->bindings) && set->flags & NFT_SET_CONSTANT)
 		return -EBUSY;
 
+	nft_ctx_init(&ctx, net, skb, info->nlh, family, table, NULL, nla);
+
 	if (!nla[NFTA_SET_ELEM_LIST_ELEMENTS])
 		return nft_set_flush(&ctx, set, genmask);