From 00c179b4c9f9f9394cc6f79e5f2a68410631fd72 Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Fri, 3 Aug 2012 17:31:48 +0200
Subject: initial version of libnftables

It adds support for table, chain and rule handling.

This also includes expression handling for each rule.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 examples/nft-chain-get.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 examples/nft-chain-get.c

(limited to 'examples/nft-chain-get.c')

diff --git a/examples/nft-chain-get.c b/examples/nft-chain-get.c
new file mode 100644
index 0000000..2756c90
--- /dev/null
+++ b/examples/nft-chain-get.c
@@ -0,0 +1,123 @@
+/*
+ * (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/nf_tables.h>
+
+#include <libmnl/libmnl.h>
+#include <libnftables/chain.h>
+
+static int table_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct nft_chain *t;
+	char buf[4096];
+
+	t = nft_chain_alloc();
+	if (t == NULL) {
+		perror("OOM");
+		goto err;
+	}
+
+	if (nft_chain_nlmsg_parse(nlh, t) < 0) {
+		perror("nft_chain_nlmsg_parse");
+		goto err_free;
+	}
+
+	nft_chain_snprintf(buf, sizeof(buf), t, NFT_CHAIN_O_DEFAULT, 0);
+	printf("%s", buf);
+
+err_free:
+	nft_chain_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;
+	struct nft_chain *t = NULL;
+	int ret;
+
+	seq = time(NULL);
+
+	if (argc == 1) {
+		nlh = nft_chain_nlmsg_build_hdr(buf, NFT_MSG_GETCHAIN, AF_INET,
+						NLM_F_DUMP, seq);
+	} else if (argc == 4) {
+		int family;
+
+		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);
+		}
+
+		t = nft_chain_alloc();
+		if (t == NULL) {
+			perror("OOM");
+			exit(EXIT_FAILURE);
+		}
+		nlh = nft_chain_nlmsg_build_hdr(buf, NFT_MSG_GETCHAIN, family,
+						NLM_F_ACK, seq);
+		nft_chain_attr_set(t, NFT_CHAIN_ATTR_TABLE, argv[2]);
+		nft_chain_attr_set(t, NFT_CHAIN_ATTR_NAME, argv[3]);
+		nft_chain_nlmsg_build_payload(nlh, t);
+		nft_chain_free(t);
+	} else {
+		fprintf(stderr, "Usage: %s [<family> <table> <chain>]\n",
+			argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	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, table_cb, 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;
+}
-- 
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