[libnftables] examples: add insert rule example

diff --git a/examples/Makefile.am b/examples/Makefile.am
index dcf798a..1d6b98f 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -10,6 +10,7 @@  check_PROGRAMS = nft-table-add		\
 		 nft-chain-del		\
 		 nft-chain-get		\
 		 nft-rule-add		\
+		 nft-rule-insert	\
 		 nft-rule-xml-add	\
 		 nft-rule-del		\
 		 nft-rule-get		\
@@ -52,6 +53,9 @@  nft_chain_get_LDADD = ../src/libnftables.la ${LIBMNL_LIBS} ${LIBXML_LIBS}
 nft_rule_add_SOURCES = nft-rule-add.c
 nft_rule_add_LDADD = ../src/libnftables.la ${LIBMNL_LIBS} ${LIBXML_LIBS}
 
+nft_rule_insert_SOURCES = nft-rule-insert.c
+nft_rule_insert_LDADD = ../src/libnftables.la ${LIBMNL_LIBS} ${LIBXML_LIBS}
+
 nft_rule_xml_add_SOURCES = nft-rule-xml-add.c
 nft_rule_xml_add_LDADD = ../src/libnftables.la ${LIBMNL_LIBS} ${LIBXML_LIBS}
 
diff --git a/examples/nft-rule-insert.c b/examples/nft-rule-insert.c
new file mode 100644
index 0000000..ddb7ad2
--- /dev/null
+++ b/examples/nft-rule-insert.c
@@ -0,0 +1,203 @@ 
+/*
+ * (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 <stddef.h>	/* for offsetof */
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <linux/netfilter/nf_tables.h>
+
+#include <libmnl/libmnl.h>
+#include <libnftables/rule.h>
+#include <libnftables/expr.h>
+
+#include <linux/netfilter_ipv4/ipt_LOG.h>
+#include <linux/netfilter/xt_iprange.h>
+
+#include <netinet/ip.h>
+
+static void add_target_log(struct nft_rule_expr *e)
+{
+	struct ipt_log_info *info;
+
+	nft_rule_expr_set(e, NFT_EXPR_TG_NAME, "LOG", strlen("LOG"));
+	nft_rule_expr_set_u32(e, NFT_EXPR_TG_REV, 0);
+
+	info = calloc(1, sizeof(struct ipt_log_info));
+	if (info == NULL)
+		return;
+
+	sprintf(info->prefix, "test: ");
+	info->prefix[sizeof(info->prefix)-1] = '\0';
+	info->logflags = 0x0f;
+	info->level = 5;
+
+	nft_rule_expr_set(e, NFT_EXPR_TG_INFO, info, sizeof(*info));
+}
+
+static void add_expr_target(struct nft_rule *r)
+{
+	struct nft_rule_expr *expr;
+
+	expr = nft_rule_expr_alloc("target");
+	if (expr == NULL)
+		return;
+
+	add_target_log(expr);
+
+	nft_rule_add_expr(r, expr);
+}
+
+static void add_match_iprange(struct nft_rule_expr *e)
+{
+	struct xt_iprange_mtinfo *info;
+
+	nft_rule_expr_set(e, NFT_EXPR_MT_NAME, "iprange", strlen("iprange"));
+	nft_rule_expr_set_u32(e, NFT_EXPR_MT_REV, 1);
+
+	info = calloc(1, sizeof(struct xt_iprange_mtinfo));
+	if (info == NULL)
+		return;
+
+	info->src_min.ip = info->dst_min.ip = inet_addr("127.0.0.1");
+	info->src_max.ip = info->dst_max.ip = inet_addr("127.0.0.1");
+	info->flags = IPRANGE_SRC;
+
+	nft_rule_expr_set(e, NFT_EXPR_MT_INFO, info, sizeof(*info));
+}
+
+static void add_expr_match(struct nft_rule *r)
+{
+	struct nft_rule_expr *expr;
+
+	expr = nft_rule_expr_alloc("match");
+	if (expr == NULL)
+		return;
+
+	add_match_iprange(expr);
+
+	nft_rule_add_expr(r, expr);
+}
+
+#define field_sizeof(t, f)	(sizeof(((t *)NULL)->f))
+
+static void add_payload2(struct nft_rule_expr *e)
+{
+	nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_BASE,
+			      NFT_PAYLOAD_NETWORK_HEADER);
+	nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_DREG, NFT_REG_1);
+	nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_OFFSET,
+			      offsetof(struct iphdr, protocol));
+	nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_LEN, 1);
+}
+
+static void add_payload(struct nft_rule *r)
+{
+	struct nft_rule_expr *expr;
+
+	expr = nft_rule_expr_alloc("payload");
+	if (expr == NULL)
+		return;
+
+	add_payload2(expr);
+
+	nft_rule_add_expr(r, expr);
+}
+
+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_rule *r = NULL;
+	int ret, family;
+	uint64_t handle;
+
+	if (argc != 5) {
+		fprintf(stderr, "Usage: %s <family> <table> <chain> <handle>\n",
+			argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	r = nft_rule_alloc();
+	if (r == NULL) {
+		perror("OOM");
+		exit(EXIT_FAILURE);
+	}
+
+	if (strcmp(argv[1], "ip") == 0)
+		family = AF_INET;
+	else if (strcmp(argv[1], "ip6") == 0)
+		family = AF_INET6;
+	else if (strcmp(argv[1], "bridge") == 0)
+		family = AF_BRIDGE;
+	else {
+		fprintf(stderr, "Unknown family: ip, ip6, bridge\n");
+		exit(EXIT_FAILURE);
+	}
+
+	nft_rule_attr_set(r, NFT_RULE_ATTR_TABLE, argv[2]);
+	nft_rule_attr_set(r, NFT_RULE_ATTR_CHAIN, argv[3]);
+
+	handle = atoi(argv[4]);
+	nft_rule_attr_set(r, NFT_RULE_ATTR_HANDLE, &handle);
+
+	add_expr_match(r);
+	add_payload(r);
+	add_expr_target(r);
+
+	char tmp[1024];
+	nft_rule_snprintf(tmp, sizeof(tmp), r, 0, 0);
+	printf("%s\n", tmp);
+
+	seq = time(NULL);
+	nlh = nft_rule_nlmsg_build_hdr(buf, NFT_MSG_NEWRULE, family,
+					NLM_F_ACK|NLM_F_CREATE,
+					seq);
+	nft_rule_nlmsg_build_payload(nlh, r);
+	nft_rule_free(r);
+
+	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;
+}