examples: XML parsing examples

Some code snipplets to add tables/chain/rules using the XML representation.

The examples contains:
 * A binary to parse/add the object using libnftables.
 * A shellscript to easily call that binary, doing some tests.
 * table/chain/rule sample XML file.

I included my name in new files, but I don't know if this is correct. Please let me know.

Instructions:
 $ cd examples/ ; make nft-table-xml-add
 # cd test/ ; ./nft-table-xml-add.sh

NOTE: Some kernel changes are required to allow reinsert exactly what is printed (handle handling, flags..)

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

1 files changed, 117 insertions, 0 deletions

diff --git a/examples/nft-table-xml-add.c b/examples/nft-table-xml-add.c
new file mode 100644
index 0000000..41df5b4
--- /dev/null
+++ b/examples/nft-table-xml-add.c
@@ -0,0 +1,117 @@
+/*
+ * 2013 by Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
+ *
+ * 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.
+ */
+
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+#include <netinet/in.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <linux/netfilter/nf_tables.h>
+
+#include <libmnl/libmnl.h>
+#include <libnftables/table.h>
+
+extern struct nft_table nft_table;
+
+int main(int argc, char *argv[])
+{
+	struct mnl_socket *nl;
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	struct nlmsghdr *nlh;
+	uint32_t portid, seq;
+	struct nft_table *t = NULL;
+	int ret;
+	int fd;
+	uint16_t family;
+	char xml[4096];
+	char reprint[4096];
+
+	if (argc < 2) {
+		printf("Usage: %s <xml-file>\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	fd = open(argv[1], O_RDONLY);
+	if (fd < 0) {
+		perror("open");
+		exit(EXIT_FAILURE);
+	}
+
+	if (read(fd, xml, sizeof(xml)) < 0) {
+		perror("read");
+		close(fd);
+		exit(EXIT_FAILURE);
+	}
+
+	t = nft_table_alloc();
+	if (t == NULL) {
+		perror("OOM");
+		close(fd);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Parsing XML now */
+	if (nft_table_parse(t, NFT_TABLE_PARSE_XML, xml) < 0) {
+		printf("E: Unable to parse XML file: %s\n", strerror(errno));
+		close(fd);
+		exit(EXIT_FAILURE);
+	}
+
+	close(fd);
+
+	nft_table_snprintf(reprint, sizeof(reprint), t, NFT_TABLE_O_XML, 0);
+	printf("Parsed:\n%s\n", reprint);
+
+
+	family = (uint16_t)nft_table_attr_get_u32(t, NFT_TABLE_ATTR_FAMILY);
+
+	seq = time(NULL);
+
+	nlh = nft_table_nlmsg_build_hdr(buf, NFT_MSG_NEWTABLE, family,
+							NLM_F_ACK, seq);
+	nft_table_nlmsg_build_payload(nlh, t);
+	nft_table_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, NULL, NULL);
+		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;
+}