src: add comment support for set declarations

Allow users to add a comment when declaring a named set.

Adds set output handling the comment in both nftables and json
format.

$ nft add table ip x
$ nft add set ip x s {type ipv4_addr\; comment "some_addrs"\; elements = {1.1.1.1, 1.2.3.4}}

$ nft list ruleset
table ip x {
	set s {
		type ipv4_addr;
		comment "some_addrs"
		elements = { 1.1.1.1, 1.2.3.4 }
	}
}

$ nft --json list ruleset
{
    "nftables": [
        {
            "metainfo": {
                "json_schema_version": 1,
                "release_name": "Capital Idea #2",
                "version": "0.9.6"
            }
        },
        {
            "table": {
                "family": "ip",
                "handle": 4857,
                "name": "x"
            }
        },
        {
            "set": {
                "comment": "some_addrs",
                "elem": [
                    "1.1.1.1",
                    "1.2.3.4"
                ],
                "family": "ip",
                "handle": 1,
                "name": "s",
                "table": "x",
                "type": "ipv4_addr"
            }
        }
    ]
}

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

1 files changed, 5 insertions, 0 deletions

diff --git a/src/mnl.c b/src/mnl.c
index e5e88f3b..388eff8f 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -1042,6 +1042,11 @@ int mnl_nft_set_add(struct netlink_ctx *ctx, struct cmd *cmd,
 				   sizeof(set->desc.field_len[0]));
 	}
 
+	if (set->comment) {
+		if (!nftnl_udata_put_strz(udbuf, NFTNL_UDATA_SET_COMMENT, set->comment))
+			memory_allocation_error();
+	}
+
 	nftnl_set_set_data(nls, NFTNL_SET_USERDATA, nftnl_udata_buf_data(udbuf),
 			   nftnl_udata_buf_len(udbuf));
 	nftnl_udata_buf_free(udbuf);