src: add `list chains' command

 # nft list chains
 table ip filter {
        chain test1 {
        }
        chain test2 {
        }
        chain input {
                type filter hook input priority 0; policy accept;
        }
 }
 table ip6 filter {
        chain test1 {
        }
        chain input {
                type filter hook input priority 0; policy accept;
        }
 }

You can also filter out per family:

 # nft list chains ip
 table ip x {
        chain y {
        }
        chain xz {
        }
        chain input {
                type filter hook input priority 0; policy accept;
        }
 }

 # nft list chains ip6
 table ip6 filter {
        chain x {
        }
        chain input {
                type filter hook input priority 0; policy accept;
        }
 }

This command only shows the chain declarations, so the content (the
definition) is omitted.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/rule.h b/include/rule.h
index f137a4c8..30b4597d 100644
--- a/include/rule.h
+++ b/include/rule.h
@@ -270,6 +270,7 @@ enum cmd_ops {
  * @CMD_OBJ_SETS:	multiple sets
  * @CMD_OBJ_RULE:	rule
  * @CMD_OBJ_CHAIN:	chain
+ * @CMD_OBJ_CHAINS:	multiple chains
  * @CMD_OBJ_TABLE:	table
  * @CMD_OBJ_RULESET:	ruleset
  * @CMD_OBJ_EXPR:	expression
@@ -283,6 +284,7 @@ enum cmd_obj {
 	CMD_OBJ_SETS,
 	CMD_OBJ_RULE,
 	CMD_OBJ_CHAIN,
+	CMD_OBJ_CHAINS,
 	CMD_OBJ_TABLE,
 	CMD_OBJ_RULESET,
 	CMD_OBJ_EXPR,