libnftables: Store top_scope in struct nft_ctx

Allow for interactive sessions to make use of defines. Since parser is
initialized for each line, top scope defines didn't persist although
they are actually useful for stuff like:

| # nft -i
| define goodports = { 22, 23, 80, 443 }
| add rule inet t c tcp dport $goodports accept
| add rule inet t c tcp sport $goodports accept

While being at it, introduce scope_alloc() and scope_free().

Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/rule.c b/src/rule.c
index 552b3c6b..4abc13c9 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -645,6 +645,15 @@ struct rule *rule_lookup_by_index(const struct chain *chain, uint64_t index)
 	return NULL;
 }
 
+struct scope *scope_alloc(void)
+{
+	struct scope *scope = xzalloc(sizeof(struct scope));
+
+	init_list_head(&scope->symbols);
+
+	return scope;
+}
+
 struct scope *scope_init(struct scope *scope, const struct scope *parent)
 {
 	scope->parent = parent;
@@ -664,6 +673,12 @@ void scope_release(const struct scope *scope)
 	}
 }
 
+void scope_free(struct scope *scope)
+{
+	scope_release(scope);
+	xfree(scope);
+}
+
 void symbol_bind(struct scope *scope, const char *identifier, struct expr *expr)
 {
 	struct symbol *sym;