examples: add libnftables example program

Create an example folder to add example source code files to show how to
use libnftables. Add first example program using the buffer API.

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

diff --git a/configure.ac b/configure.ac
index 503883f28c664b5df31324a29308d8b11dba4ba3..d321c960562b374c469327f259d972b9d77300f9 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -145,6 +145,7 @@ AC_CONFIG_FILES([                                   \
                files/osf/Makefile                      \
                doc/Makefile                            \
                py/Makefile                             \
+               examples/Makefile                       \
                ])
 AC_OUTPUT
 

diff --git a/examples/Makefile.am b/examples/Makefile.am
new file mode 100644 (file)
index 0000000..dd637fe
--- /dev/null
+++ b/examples/Makefile.am
@@ -0,0 +1,3 @@
+noinst_PROGRAMS        = nft-buffer
+
+LDADD = $(top_builddir)/src/libnftables.la

diff --git a/examples/nft-buffer.c b/examples/nft-buffer.c
new file mode 100644 (file)
index 0000000..1c4b1e0
--- /dev/null
+++ b/examples/nft-buffer.c
@@ -0,0 +1,34 @@
+/* gcc nft-buffer.c -o nft-buffer -lnftables */
+#include <stdlib.h>
+#include <nftables/libnftables.h>
+
+const char ruleset[] =
+       "flush ruleset;"
+       "add table x;"
+       "add chain x y { type filter hook input priority 0; };"
+       "add rule x y counter;";
+
+int main(void)
+{
+       struct nft_ctx *ctx;
+       int err;
+
+       ctx = nft_ctx_new(0);
+       if (!ctx) {
+               perror("cannot allocate nft context");
+               return EXIT_FAILURE;
+       }
+
+       /* create ruleset: all commands in the buffer are atomically applied */
+       err = nft_run_cmd_from_buffer(ctx, ruleset);
+       if (err < 0)
+               fprintf(stderr, "failed to run nftables command\n");
+
+       err = nft_run_cmd_from_buffer(ctx, "list ruleset");
+       if (err < 0)
+               fprintf(stderr, "failed to run nftables command\n");
+
+       nft_ctx_free(ctx);
+
+       return EXIT_SUCCESS;
+}