examples: add nft-ct-helper-{add,get,del}

nft-ct-helper-{add,get,del}: add, get, or delete ct helper objects from the specified table.

Examples:
  % ./nft-ct-helper-get ip filter
  <nothing>
  % ./nft-ct-helper-add ip filter sip-5060 sip udp
  % ./nft-ct-helper-get ip filter
  table filter name sip-5060 use 0 [ ct_helper name sip family 2 protocol 17 ]
  % ./nft-ct-helper-del ip filter sip-5060
  % ./nft-ct-helper-get ip filter
  <nothing>

Signed-off-by: Yang Zheng <tomsun.0.7@gmail.com>
Acked-by: Arturo Borrero Gonzalez <arturo@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 150 insertions, 0 deletions

diff --git a/examples/nft-ct-helper-get.c b/examples/nft-ct-helper-get.c
new file mode 100644
index 0000000..94bd0cd
--- /dev/null
+++ b/examples/nft-ct-helper-get.c
@@ -0,0 +1,150 @@
+/*
+ * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
+ */
+
+
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+#include <netinet/in.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+
+#include <libmnl/libmnl.h>
+#include <libnftnl/object.h>
+
+static int obj_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct nftnl_obj *t;
+	char buf[4096];
+	uint32_t *type = data;
+
+	t = nftnl_obj_alloc();
+	if (t == NULL) {
+		perror("OOM");
+		goto err;
+	}
+
+	if (nftnl_obj_nlmsg_parse(nlh, t) < 0) {
+		perror("nftnl_obj_nlmsg_parse");
+		goto err_free;
+	}
+
+	nftnl_obj_snprintf(buf, sizeof(buf), t, *type, 0);
+	printf("%s\n", buf);
+
+err_free:
+	nftnl_obj_free(t);
+err:
+	return MNL_CB_OK;
+}
+
+int main(int argc, char *argv[])
+{
+	struct mnl_socket *nl;
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	struct nlmsghdr *nlh;
+	uint32_t portid, seq, family;
+	struct nftnl_obj *t = NULL;
+	int ret;
+	uint32_t type = NFTNL_OUTPUT_DEFAULT;
+
+	if (argc < 3 || argc > 5) {
+		fprintf(stderr, "%s <family> <table> [<obj>] [<default|xml|json>]\n",
+			argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	if (strcmp(argv[1], "ip") == 0)
+		family = NFPROTO_IPV4;
+	else if (strcmp(argv[1], "ip6") == 0)
+		family = NFPROTO_IPV6;
+	else if (strcmp(argv[1], "inet") == 0)
+		family = NFPROTO_INET;
+	else if (strcmp(argv[1], "unspec") == 0)
+		family = NFPROTO_UNSPEC;
+	else {
+		fprintf(stderr, "Unknown family: ip, ip6, inet, unspec");
+		exit(EXIT_FAILURE);
+	}
+
+	if (strcmp(argv[argc-1], "xml") == 0) {
+		type = NFTNL_OUTPUT_XML;
+		argv[argc-1] = NULL;
+		argc--;
+	}else if (strcmp(argv[argc-1], "json") == 0) {
+		type = NFTNL_OUTPUT_JSON;
+		argv[argc-1] = NULL;
+		argc--;
+	} else if (strcmp(argv[argc - 1], "default") == 0) {
+		argc--;
+	}
+
+	if (argc == 3 || argc == 4) {
+		t = nftnl_obj_alloc();
+		if (t == NULL) {
+			perror("OOM");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	seq = time(NULL);
+        nftnl_obj_set_u32(t, NFTNL_OBJ_TYPE, NFT_OBJECT_CT_HELPER);
+	if (argc < 4) {
+		nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETOBJ, family,
+					    NLM_F_DUMP, seq);
+		if (argc == 3) {
+			nftnl_obj_set(t, NFTNL_OBJ_TABLE, argv[2]);
+			nftnl_obj_nlmsg_build_payload(nlh, t);
+			nftnl_obj_free(t);
+		}
+	} else {
+		nftnl_obj_set(t, NFTNL_OBJ_TABLE, argv[2]);
+		nftnl_obj_set(t, NFTNL_OBJ_NAME, argv[3]);
+
+		nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETOBJ, family,
+					    NLM_F_ACK, seq);
+		nftnl_obj_nlmsg_build_payload(nlh, t);
+		nftnl_obj_free(t);
+	}
+
+	nl = mnl_socket_open(NETLINK_NETFILTER);
+	if (nl == NULL) {
+		perror("mnl_socket_open");
+		exit(EXIT_FAILURE);
+	}
+
+	if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
+		perror("mnl_socket_bind");
+		exit(EXIT_FAILURE);
+	}
+	portid = mnl_socket_get_portid(nl);
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_send");
+		exit(EXIT_FAILURE);
+	}
+
+	ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+	while (ret > 0) {
+		ret = mnl_cb_run(buf, ret, seq, portid, obj_cb, &type);
+		if (ret <= 0)
+			break;
+		ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+	}
+	if (ret == -1) {
+		perror("error");
+		exit(EXIT_FAILURE);
+	}
+	mnl_socket_close(nl);
+
+	return EXIT_SUCCESS;
+}