add xtables-events

Add new program to listen to rule updates:

shell$ xtables-events
-A INPUT -m state --state ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-D INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-D INPUT -m state --state ESTABLISHED -j ACCEPT

You can use `-c' option to display counters.

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

1 files changed, 208 insertions, 0 deletions

diff --git a/iptables/xtables-events.c b/iptables/xtables-events.c
new file mode 100644
index 00000000..2600a250
--- /dev/null
+++ b/iptables/xtables-events.c
@@ -0,0 +1,208 @@
+/*
+ * (C) 2012-2013 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 <getopt.h>
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nf_tables.h>
+
+#include <libmnl/libmnl.h>
+#include <libnftables/table.h>
+#include <libnftables/chain.h>
+#include <libnftables/rule.h>
+
+#include <include/xtables.h>
+#include "iptables.h" /* for xtables_globals */
+#include "xtables-multi.h"
+#include "nft.h"
+
+static int table_cb(const struct nlmsghdr *nlh, int type)
+{
+	struct nft_table *t;
+	char buf[4096];
+
+	t = nft_table_alloc();
+	if (t == NULL) {
+		perror("OOM");
+		goto err;
+	}
+
+	if (nft_table_nlmsg_parse(nlh, t) < 0) {
+		perror("nft_table_nlmsg_parse");
+		goto err_free;
+	}
+
+	nft_table_snprintf(buf, sizeof(buf), t, NFT_TABLE_O_DEFAULT, 0);
+	/* FIXME: define syntax to represent table events */
+	printf("# [table: %s]\t%s", type == NFT_MSG_NEWTABLE ? "NEW" : "DEL", buf);
+
+err_free:
+	nft_table_free(t);
+err:
+	return MNL_CB_OK;
+}
+
+static bool counters;
+
+static int rule_cb(const struct nlmsghdr *nlh, int type)
+{
+	struct nft_rule *r;
+
+	r = nft_rule_alloc();
+	if (r == NULL) {
+		perror("OOM");
+		goto err;
+	}
+
+	if (nft_rule_nlmsg_parse(nlh, r) < 0) {
+		perror("nft_rule_nlmsg_parse");
+		goto err_free;
+	}
+
+	switch(nft_rule_attr_get_u8(r, NFT_RULE_ATTR_FAMILY)) {
+	case AF_INET:
+		printf("-4 ");
+		break;
+	case AF_INET6:
+		printf("-6 ");
+		break;
+	default:
+		break;
+	}
+
+	nft_rule_print_save(r, type == NFT_MSG_NEWRULE ? NFT_RULE_APPEND :
+							 NFT_RULE_DEL,
+			    counters);
+err_free:
+	nft_rule_free(r);
+err:
+	return MNL_CB_OK;
+}
+
+static int chain_cb(const struct nlmsghdr *nlh, int type)
+{
+	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);
+	/* FIXME: define syntax to represent chain events */
+	printf("# [chain: %s]\t%s", type == NFT_MSG_NEWCHAIN ? "NEW" : "DEL", buf);
+
+err_free:
+	nft_chain_free(t);
+err:
+	return MNL_CB_OK;
+}
+
+static int events_cb(const struct nlmsghdr *nlh, void *data)
+{
+	int ret = MNL_CB_OK;
+	int type = nlh->nlmsg_type & 0xFF;
+
+	switch(type) {
+	case NFT_MSG_NEWTABLE:
+	case NFT_MSG_DELTABLE:
+		ret = table_cb(nlh, type);
+		break;
+	case NFT_MSG_NEWCHAIN:
+	case NFT_MSG_DELCHAIN:
+		ret = chain_cb(nlh, type);
+		break;
+	case NFT_MSG_NEWRULE:
+	case NFT_MSG_DELRULE:
+		ret = rule_cb(nlh, type);
+		break;
+	}
+
+	return ret;
+}
+
+static const struct option options[] = {
+	{.name = "counters", .has_arg = false, .val = 'c'},
+	{NULL},
+};
+
+static void print_usage(const char *name, const char *version)
+{
+	fprintf(stderr, "Usage: %s [-c]\n"
+			"	   [ --counters ]\n", name);
+	exit(EXIT_FAILURE);
+}
+
+int xtables_events_main(int argc, char *argv[])
+{
+	struct mnl_socket *nl;
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	int ret, c;
+
+	xtables_globals.program_name = "xtables-events";
+	/* XXX xtables_init_all does several things we don't want */
+	c = xtables_init_all(&xtables_globals, NFPROTO_IPV4);
+	if (c < 0) {
+		fprintf(stderr, "%s/%s Failed to initialize xtables\n",
+				xtables_globals.program_name,
+				xtables_globals.program_version);
+		exit(1);
+	}
+#if defined(ALL_INCLUSIVE) || defined(NO_SHARED_LIBS)
+	init_extensions();
+	init_extensions4();
+#endif
+
+	while ((c = getopt_long(argc, argv, "c", options, NULL)) != -1) {
+		switch (c) {
+	        case 'c':
+			counters = true;
+			break;
+		}
+	}
+
+	nl = mnl_socket_open(NETLINK_NETFILTER);
+	if (nl == NULL) {
+		perror("mnl_socket_open");
+		exit(EXIT_FAILURE);
+	}
+
+	if (mnl_socket_bind(nl, (1 << (NFNLGRP_NFTABLES-1)), MNL_SOCKET_AUTOPID) < 0) {
+		perror("mnl_socket_bind");
+		exit(EXIT_FAILURE);
+	}
+
+	ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+	while (ret > 0) {
+		ret = mnl_cb_run(buf, ret, 0, 0, events_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;
+}