With this example, we can parse the elements in the ruleset and create the
netlink message with the action associated. For example:
- Flush ruleset
- Add, delete or flush tables/chains
- Add, delete sets
- Add, delete set elements
- Add, delete, replace or prepend rules
Signed-off-by: Alvaro Neira Ayuso <alvaroneay@xxxxxxxxx>
---
[changes in v9]
* Fixed leaks in the error path
* Used the functions nft_ruleset_*_build_msg to make the code more clear
* Changed the code to make the set elements netlink message to use the function
nft_set_elems_nlmsg_build_payload_iter.
examples/Makefile.am | 4 +
examples/nft-ruleset-parse-file.c | 486 +++++++++++++++++++++++++++++++++++++
2 files changed, 490 insertions(+)
create mode 100644 examples/nft-ruleset-parse-file.c
diff --git a/examples/Makefile.am b/examples/Makefile.am
index fafcb76..e002d36 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -22,6 +22,7 @@ check_PROGRAMS = nft-table-add \
nft-set-elem-get \
nft-set-elem-del \
nft-ruleset-get \
+ nft-ruleset-parse-file \
nft-compat-get
nft_table_add_SOURCES = nft-table-add.c
@@ -90,5 +91,8 @@ nft_set_elem_get_LDADD = ../src/libnftnl.la ${LIBMNL_LIBS}
nft_ruleset_get_SOURCES = nft-ruleset-get.c
nft_ruleset_get_LDADD = ../src/libnftnl.la ${LIBMNL_LIBS}
+nft_ruleset_parse_file_SOURCES = nft-ruleset-parse-file.c
+nft_ruleset_parse_file_LDADD = ../src/libnftnl.la ${LIBMNL_LIBS}
+
nft_compat_get_SOURCES = nft-compat-get.c
nft_compat_get_LDADD = ../src/libnftnl.la ${LIBMNL_LIBS}
diff --git a/examples/nft-ruleset-parse-file.c b/examples/nft-ruleset-parse-file.c
new file mode 100644
index 0000000..7770a15
--- /dev/null
+++ b/examples/nft-ruleset-parse-file.c
@@ -0,0 +1,486 @@
+/*
+ * (C) 2014 by Alvaro Neira Ayuso <alvaroneay@xxxxxxxxx>
+ *
+ * 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.
+ */
+
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+#include <stddef.h> /* for offsetof */
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <errno.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nf_tables.h>
+
+#include <libmnl/libmnl.h>
+#include <libnftnl/ruleset.h>
+#include <libnftnl/table.h>
+#include <libnftnl/chain.h>
+#include <libnftnl/rule.h>
+#include <libnftnl/set.h>
+
+struct mnl_nlmsg_batch *batch;
+uint32_t seq;
+
+static int nft_ruleset_set_elems(const struct nft_parse_ctx *ctx)
+{
+ struct nft_set_elems_iter *iter_elems;
+ uint16_t nl_type, nl_flags;
+ uint32_t cmd;
+ struct nlmsghdr *nlh;
+ struct nft_set *set;
+
+ cmd = nft_ruleset_ctx_get_u32(ctx, NFT_RULESET_CTX_CMD);
+
+ set = nft_ruleset_ctx_get(ctx, NFT_RULESET_CTX_SET);
+ if (set == NULL)
+ return -1;
+
+ switch (cmd) {
+ case NFT_CMD_ADD:
+ nl_type = NFT_MSG_NEWSETELEM;
+ nl_flags = NLM_F_CREATE|NLM_F_EXCL|NLM_F_ACK;
+ break;
+ case NFT_CMD_DELETE:
+ nl_type = NFT_MSG_DELSETELEM;
+ /* This will generate an ACK message for each request. When
+ * removing NLM_F_ACK, the kernel will only report when things
+ * go wrong
+ */
+ nl_flags = NLM_F_ACK;
+ break;
+ default:
+ goto err;
+ }
+
+ iter_elems = nft_set_elems_iter_create(set);
+ if (iter_elems == NULL)
+ goto err;
+
+ nlh = nft_set_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch), nl_type,
+ nft_set_attr_get_u32(set,
+ NFT_SET_ATTR_FAMILY),
+ nl_flags, seq++);
+
+ nft_set_elems_nlmsg_build_payload_iter(nlh, iter_elems);
+ mnl_nlmsg_batch_next(batch);
+
+ nft_set_elems_iter_destroy(iter_elems);
+ nft_set_free(set);
+ return 0;
+err:
+ nft_set_free(set);
+ return -1;
+}
+
+static int nft_ruleset_set(const struct nft_parse_ctx *ctx)
+{
+
+ struct nlmsghdr *nlh;
+ uint16_t nl_type, nl_flags;
+ struct nft_set *set;
+ uint32_t cmd;
+ int ret;
+
+ cmd = nft_ruleset_ctx_get_u32(ctx, NFT_RULESET_CTX_CMD);
+
+ set = nft_ruleset_ctx_get(ctx, NFT_RULESET_CTX_SET);
+ if (set == NULL)
+ return -1;
+
+ switch (cmd) {
+ case NFT_CMD_ADD:
+ nl_type = NFT_MSG_NEWSET;
+ nl_flags = NLM_F_CREATE|NLM_F_ACK;
+ break;
+ case NFT_CMD_DELETE:
+ nl_type = NFT_MSG_DELSET;
+ nl_flags = NLM_F_ACK;
+ break;
+ default:
+ goto err;
+ }
+
+ nlh = nft_set_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
+ nl_type,
+ nft_set_attr_get_u32(set,
+ NFT_SET_ATTR_FAMILY),
+ nl_flags,
+ seq++);
+
+ nft_set_nlmsg_build_payload(nlh, set);
+ mnl_nlmsg_batch_next(batch);
+
+ ret = nft_ruleset_set_elems(ctx);
+ return ret;
+err:
+ nft_set_free(set);
+ return -1;
+}
+
+static int nft_ruleset_rule_build_msg(const struct nft_parse_ctx *ctx,
+ uint32_t cmd, struct nft_rule *rule)
+{
+ struct nlmsghdr *nlh;
+ uint16_t nl_type, nl_flags;
+
+ switch (cmd) {
+ case NFT_CMD_ADD:
+ nl_type = NFT_MSG_NEWRULE;
+ nl_flags = NLM_F_APPEND|NLM_F_CREATE|NLM_F_ACK;
+ nft_rule_attr_unset(rule, NFT_RULE_ATTR_HANDLE);
+ break;
+ case NFT_CMD_DELETE:
+ nl_type = NFT_MSG_DELRULE;
+ nl_flags = NLM_F_ACK;
+ break;
+ case NFT_CMD_REPLACE:
+ nl_type = NFT_MSG_NEWRULE;
+ nl_flags = NLM_F_REPLACE|NLM_F_ACK;
+ break;
+ case NFT_CMD_INSERT:
+ nl_type = NFT_MSG_NEWRULE;
+ nl_flags = NLM_F_CREATE|NLM_F_ACK;
+ nft_rule_attr_unset(rule, NFT_RULE_ATTR_HANDLE);
+ break;
+ default:
+ return -1;
+ }
+
+ nlh = nft_rule_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
+ nl_type,
+ nft_rule_attr_get_u32(rule,
+ NFT_RULE_ATTR_FAMILY),
+ nl_flags,
+ seq++);
+
+ nft_rule_nlmsg_build_payload(nlh, rule);
+ mnl_nlmsg_batch_next(batch);
+
+ return 0;
+}
+
+static int nft_ruleset_rule(const struct nft_parse_ctx *ctx)
+{
+ struct nft_rule *rule;
+ int ret;
+ uint32_t cmd;
+
+ cmd = nft_ruleset_ctx_get_u32(ctx, NFT_RULESET_CTX_CMD);
+
+ rule = nft_ruleset_ctx_get(ctx, NFT_RULESET_CTX_RULE);
+ if (rule == NULL)
+ return -1;
+
+ ret = nft_ruleset_rule_build_msg(ctx, cmd, rule);
+ nft_rule_free(rule);
+
+ return ret;
+}
+
+static int nft_ruleset_flush_rules(const struct nft_parse_ctx *ctx)
+{
+ struct nft_rule *nlr;
+ struct nft_table *nlt;
+ struct nft_chain *nlc;
+ uint32_t type;
+ int ret;
+
+ nlr = nft_rule_alloc();
+ if (nlr == NULL)
+ return -1;
+
+ type = nft_ruleset_ctx_get_u32(ctx, NFT_RULESET_CTX_TYPE);
+ switch (type) {
+ case NFT_RULESET_TABLE:
+ nlt = nft_ruleset_ctx_get(ctx, NFT_RULESET_CTX_TABLE);
+ nft_rule_attr_set(nlr, NFT_RULE_ATTR_TABLE,
+ nft_table_attr_get(nlt, NFT_TABLE_ATTR_NAME));
+ nft_rule_attr_set(nlr, NFT_RULE_ATTR_FAMILY,
+ nft_table_attr_get(nlt, NFT_TABLE_ATTR_FAMILY));
+ break;
+ case NFT_RULESET_CHAIN:
+ nlc = nft_ruleset_ctx_get(ctx, NFT_RULESET_CTX_CHAIN);
+ nft_rule_attr_set(nlr, NFT_RULE_ATTR_TABLE,
+ nft_chain_attr_get(nlc,
+ NFT_CHAIN_ATTR_TABLE));
+ nft_rule_attr_set(nlr, NFT_RULE_ATTR_CHAIN,
+ nft_chain_attr_get(nlc,
+ NFT_CHAIN_ATTR_NAME));
+ nft_rule_attr_set(nlr, NFT_RULE_ATTR_FAMILY,
+ nft_chain_attr_get(nlc, NFT_TABLE_ATTR_FAMILY));
+ break;
+ default:
+ goto err;
+ }
+
+ ret = nft_ruleset_rule_build_msg(ctx, NFT_CMD_DELETE, nlr);
+ nft_rule_free(nlr);
+
+ return ret;
+err:
+ nft_rule_free(nlr);
+ return -1;
+}
+
+static int nft_ruleset_chain(const struct nft_parse_ctx *ctx)
+{
+ struct nlmsghdr *nlh;
+ uint16_t nl_type, nl_flags;
+ uint32_t cmd;
+ struct nft_chain *chain;
+
+ cmd = nft_ruleset_ctx_get_u32(ctx, NFT_RULESET_CTX_CMD);
+
+ chain = nft_ruleset_ctx_get(ctx, NFT_RULESET_CTX_CHAIN);
+ if (chain == NULL)
+ return -1;
+
+ switch (cmd) {
+ case NFT_CMD_ADD:
+ nl_type = NFT_MSG_NEWCHAIN;
+ nl_flags = NLM_F_CREATE|NLM_F_ACK;
+ break;
+ case NFT_CMD_DELETE:
+ nl_type = NFT_MSG_DELCHAIN;
+ nl_flags = NLM_F_ACK;
+ break;
+ case NFT_CMD_FLUSH:
+ return nft_ruleset_flush_rules(ctx);
+ default:
+ goto err;
+ }
+
+ nft_chain_attr_unset(chain, NFT_CHAIN_ATTR_HANDLE);
+ nlh = nft_chain_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
+ nl_type,
+ nft_chain_attr_get_u32(chain,
+ NFT_CHAIN_ATTR_FAMILY),
+ nl_flags,
+ seq++);
+
+ nft_chain_nlmsg_build_payload(nlh, chain);
+ mnl_nlmsg_batch_next(batch);
+
+ nft_chain_free(chain);
+ return 0;
+err:
+ nft_chain_free(chain);
+ return -1;
+}
+
+static int nft_ruleset_table_build_msg(const struct nft_parse_ctx *ctx,
+ uint32_t cmd, struct nft_table *table)
+{
+ struct nlmsghdr *nlh;
+ uint16_t nl_type, nl_flags;
+
+ switch (cmd) {
+ case NFT_CMD_ADD:
+ nl_type = NFT_MSG_NEWTABLE;
+ nl_flags = NLM_F_CREATE|NLM_F_ACK;
+ break;
+ case NFT_CMD_DELETE:
+ nl_type = NFT_MSG_DELTABLE;
+ nl_flags = NLM_F_ACK;
+ break;
+ case NFT_CMD_FLUSH:
+ return nft_ruleset_flush_rules(ctx);
+ default:
+ return -1;
+ }
+
+ nlh = nft_table_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
+ nl_type,
+ nft_table_attr_get_u32(table,
+ NFT_TABLE_ATTR_FAMILY),
+ nl_flags,
+ seq++);
+
+ nft_table_nlmsg_build_payload(nlh, table);
+ mnl_nlmsg_batch_next(batch);
+
+ return 0;
+}
+
+static int nft_ruleset_table(const struct nft_parse_ctx *ctx)
+{
+ struct nft_table *table;
+ uint32_t cmd;
+ int ret;
+
+ cmd = nft_ruleset_ctx_get_u32(ctx, NFT_RULESET_CTX_CMD);
+
+ table = nft_ruleset_ctx_get(ctx, NFT_RULESET_CTX_TABLE);
+ if (table == NULL)
+ return -1;
+
+ ret = nft_ruleset_table_build_msg(ctx, cmd, table);
+ nft_table_free(table);
+
+ return ret;
+}
+
+static int nft_ruleset_flush_ruleset(const struct nft_parse_ctx *ctx)
+{
+ struct nft_table *table;
+ int ret;
+
+ table = nft_table_alloc();
+ if (table == NULL)
+ return -1;
+
+ ret = nft_ruleset_table_build_msg(ctx, NFT_CMD_DELETE, table);
+ nft_table_free(table);
+
+ return ret;
+}
+
+static int ruleset_elems_cb(const struct nft_parse_ctx *ctx)
+{
+ uint32_t type;
+ int ret;
+
+ type = nft_ruleset_ctx_get_u32(ctx, NFT_RULESET_CTX_TYPE);
+
+ switch (type) {
+ case NFT_RULESET_TABLE:
+ ret = nft_ruleset_table(ctx);
+ break;
+ case NFT_RULESET_CHAIN:
+ ret = nft_ruleset_chain(ctx);
+ break;
+ case NFT_RULESET_RULE:
+ ret = nft_ruleset_rule(ctx);
+ break;
+ case NFT_RULESET_SET:
+ ret = nft_ruleset_set(ctx);
+ break;
+ case NFT_RULESET_SET_ELEMS:
+ ret = nft_ruleset_set_elems(ctx);
+ break;
+ case NFT_RULESET_RULESET:
+ ret = nft_ruleset_flush_ruleset(ctx);
+ break;
+ default:
+ return -1;
+ }
+
+ return ret;
+}
+
+int main(int argc, char *argv[])
+{
+ struct nft_parse_err *err;
+ const char *filename;
+ FILE *fp;
+ int ret = -1, len, batching, portid;
+ uint32_t ruleset_seq;
+ char buf[MNL_SOCKET_BUFFER_SIZE];
+ struct mnl_socket *nl;
+
+ if (argc < 2) {
+ printf("Usage: %s <file>\n", argv[0]);
+ exit(EXIT_FAILURE);
+ }
+
+ fp = fopen(argv[1], "r");
+ if (fp == NULL) {
+ printf("unable to open file %s: %s\n", argv[1],
+ strerror(errno));
+ exit(EXIT_FAILURE);
+ }
+
+ err = nft_parse_err_alloc();
+ if (err == NULL) {
+ perror("error");
+ exit(EXIT_FAILURE);
+ }
+
+ batching = nft_batch_is_supported();
+ if (batching < 0) {
+ perror("Cannot talk to nfnetlink");
+ exit(EXIT_FAILURE);
+ }
+
+ seq = time(NULL);
+ batch = mnl_nlmsg_batch_start(buf, sizeof(buf));
+
+ if (batching) {
+ nft_batch_begin(mnl_nlmsg_batch_current(batch), seq++);
+ mnl_nlmsg_batch_next(batch);
+ }
+ ruleset_seq = seq;
+
+ filename = argv[1];
+ len = strlen(filename);
+ if (strcmp(&filename[len-5], ".json") == 0)
+ ret = nft_ruleset_parse_file_cb(NFT_PARSE_JSON, fp, err, NULL,
+ &ruleset_elems_cb);
+ else if (strcmp(&filename[len-4], ".xml") == 0)
+ ret = nft_ruleset_parse_file_cb(NFT_PARSE_XML, fp, err, NULL,
+ &ruleset_elems_cb);
+ else {
+ printf("the filename %s must to end in .xml or .json\n",
+ filename);
+ exit(EXIT_FAILURE);
+ }
+
+ if (ret < 0) {
+ nft_parse_perror("fail", err);
+ exit(EXIT_FAILURE);
+ }
+
+ fclose(fp);
+
+ if (batching) {
+ nft_batch_end(mnl_nlmsg_batch_current(batch), seq++);
+ mnl_nlmsg_batch_next(batch);
+ }
+
+ 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, mnl_nlmsg_batch_head(batch),
+ mnl_nlmsg_batch_size(batch)) < 0) {
+ perror("mnl_socket_send");
+ exit(EXIT_FAILURE);
+ }
+
+ mnl_nlmsg_batch_stop(batch);
+
+ ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+ while (ret > 0) {
+ ret = mnl_cb_run(buf, ret, ruleset_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;
+}
--
1.7.10.4
--
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