examples: add insert rule example

This program can insert a rule after a rule given by
its handle.

Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/examples/Makefile.am b/examples/Makefile.am
index 8985d74d7dce80325f567585ee038e4dff43336c..bf28bae889fda09637722eafb58fbb64397ce27d 100644 (file)
--- 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}
 nft_rule_add_SOURCES = nft-rule-add.c
 nft_rule_add_LDADD = ../src/libnftables.la ${LIBMNL_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}
 

diff --git a/examples/nft-rule-insert.c b/examples/nft-rule-insert.c
new file mode 100644 (file)
index 0000000..1418127
--- /dev/null
+++ b/examples/nft-rule-insert.c
@@ -0,0 +1,204 @@
+/*
+ * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
+ * (C) 2013 by Eric Leblond <eric@regit.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_POSITION, &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;
+}