src: add comment support for chains

This patch enables the user to specify a comment when adding a chain.

Relies on kernel space supporting userdata for chains.

> nft add table ip filter
> nft add chain ip filter input { comment "test"\; type filter hook input priority 0\; policy accept\; }
> list ruleset

table ip filter {
	chain input {
		comment "test"
		type filter hook input priority filter; policy accept;
	}
}

Signed-off-by: Jose M. Guisado Gomez <guigom@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/parser_bison.y b/src/parser_bison.y
index 524903fd..9bf4f71f 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -1723,6 +1723,14 @@ chain_block		:	/* empty */	{ $$ = $<chain>-1; }
 				list_add_tail(&$2->list, &$1->rules);
 				$$ = $1;
 			}
+			|	chain_block	comment_spec	stmt_separator
+			{
+				if (already_set($1->comment, &@2, state)) {
+					xfree($2);
+					YYERROR;
+				}
+				$1->comment = $2;
+			}
 			;
 
 subchain_block		:	/* empty */	{ $$ = $<chain>-1; }