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authorPablo Neira Ayuso <pablo@netfilter.org>2012-08-03 17:31:48 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2012-10-11 15:15:02 +0200
commit00c179b4c9f9f9394cc6f79e5f2a68410631fd72 (patch)
tree00057636d125f3c89e2b9485c67c4283a98d91b2 /examples/nft-rule-add.c
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>
Diffstat (limited to 'examples/nft-rule-add.c')
-rw-r--r--examples/nft-rule-add.c199
1 files changed, 199 insertions, 0 deletions
diff --git a/examples/nft-rule-add.c b/examples/nft-rule-add.c
new file mode 100644
index 0000000..5fbc796
--- /dev/null
+++ b/examples/nft-rule-add.c
@@ -0,0 +1,199 @@
+/*
+ * (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 <libnftables/payload.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;
+
+ if (argc != 4) {
+ fprintf(stderr, "Usage: %s <family> <table> <chain>\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]);
+
+ add_expr_match(r);
+ add_expr_target(r);
+// add_payload(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_APPEND|NLM_F_ACK, 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;
+}