src: listing of stateful objects

This patch allows you to dump existing stateful objects, eg.

 # nft list ruleset
 table ip filter {
        counter test {
                packets 64 bytes 1268
        }

        quota test {
                over 1 mbytes used 1268 bytes
        }

        chain input {
                type filter hook input priority 0; policy accept;
                quota name test drop
                counter name test
        }
 }

 # nft list quotas
 table ip filter {
        quota test {
                over 1 mbytes used 1268 bytes
        }
 }
 # nft list counters
 table ip filter {
        counter test {
                packets 64 bytes 1268
        }
 }

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 59 insertions, 0 deletions

diff --git a/src/mnl.c b/src/mnl.c
index 257b630e..534d02f4 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -16,6 +16,7 @@
 #include <libnftnl/rule.h>
 #include <libnftnl/expr.h>
 #include <libnftnl/set.h>
+#include <libnftnl/object.h>
 #include <libnftnl/batch.h>
 
 #include <linux/netfilter/nfnetlink.h>
@@ -795,6 +796,64 @@ err:
 	return NULL;
 }
 
+static int obj_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct nftnl_obj_list *nln_list = data;
+	struct nftnl_obj *n;
+
+	if (check_genid(nlh) < 0)
+		return MNL_CB_ERROR;
+
+	n = nftnl_obj_alloc();
+	if (n == NULL)
+		memory_allocation_error();
+
+	if (nftnl_obj_nlmsg_parse(nlh, n) < 0)
+		goto err_free;
+
+	nftnl_obj_list_add_tail(n, nln_list);
+	return MNL_CB_OK;
+
+err_free:
+	nftnl_obj_free(n);
+	return MNL_CB_OK;
+}
+
+
+struct nftnl_obj_list *
+mnl_nft_obj_dump(struct mnl_socket *nf_sock, int family, const char *table)
+{
+	struct nftnl_obj_list *nln_list;
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	struct nftnl_obj *n;
+	struct nlmsghdr *nlh;
+	int ret;
+
+	n = nftnl_obj_alloc();
+	if (n == NULL)
+		memory_allocation_error();
+
+	nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETOBJ, family,
+				    NLM_F_DUMP | NLM_F_ACK, seq);
+	if (table != NULL)
+		nftnl_obj_set(n, NFTNL_OBJ_TABLE, table);
+	nftnl_obj_nlmsg_build_payload(nlh, n);
+	nftnl_obj_free(n);
+
+	nln_list = nftnl_obj_list_alloc();
+	if (nln_list == NULL)
+		memory_allocation_error();
+
+	ret = nft_mnl_talk(nf_sock, nlh, nlh->nlmsg_len, obj_cb, nln_list);
+	if (ret < 0)
+		goto err;
+
+	return nln_list;
+err:
+	nftnl_obj_list_free(nln_list);
+	return NULL;
+}
+
 static int set_get_cb(const struct nlmsghdr *nlh, void *data)
 {
 	struct nftnl_set *s = data;