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>

2 files changed, 17 insertions, 0 deletions

diff --git a/tests/shell/testcases/optionals/comments_chain_0 b/tests/shell/testcases/optionals/comments_chain_0
new file mode 100755
index 00000000..fba961c7
--- /dev/null
+++ b/tests/shell/testcases/optionals/comments_chain_0
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+EXPECTED='table ip test_table {
+	chain test_chain {
+		comment "test"
+	}
+}
+'
+
+set -e
+
+$NFT -f - <<< "$EXPECTED"
diff --git a/tests/shell/testcases/optionals/dumps/comments_chain_0.nft b/tests/shell/testcases/optionals/dumps/comments_chain_0.nft
new file mode 100644
index 00000000..be3d8f33
--- /dev/null
+++ b/tests/shell/testcases/optionals/dumps/comments_chain_0.nft
@@ -0,0 +1,5 @@
+table ip test_table {
+	chain test_chain {
+		comment "test"
+	}
+}