examples: load ruleset from JSON

Add an example to load a ruleset file expressed in JSON.

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

diff --git a/examples/Makefile.am b/examples/Makefile.am
index dd637fe3134083126124861dc0239d9a792bddaa..c972170d3fdc62a3da5491915ac610f1d4c901f7 100644 (file)
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -1,3 +1,4 @@
-noinst_PROGRAMS        = nft-buffer
+noinst_PROGRAMS        = nft-buffer            \
+                 nft-json-file
 
 LDADD = $(top_builddir)/src/libnftables.la

diff --git a/examples/json-ruleset.nft b/examples/json-ruleset.nft
new file mode 100644 (file)
index 0000000..acea178
--- /dev/null
+++ b/examples/json-ruleset.nft
@@ -0,0 +1,43 @@
+{
+  "nftables": [
+    {
+      "flush": {
+        "ruleset": {
+          "family": "ip"
+        }
+      }
+    },
+    {
+      "table": {
+        "family": "ip",
+        "name": "x"
+      }
+    },
+    {
+      "chain": {
+        "family": "ip",
+        "table": "x",
+        "name": "y",
+        "type": "filter",
+        "hook": "input",
+        "prio": 0,
+        "policy": "accept"
+      }
+    },
+    {
+      "rule": {
+        "family": "ip",
+        "table": "x",
+        "chain": "y",
+        "expr": [
+          {
+            "counter": {
+              "packets": 0,
+              "bytes": 0
+            }
+          }
+        ]
+      }
+    }
+  ]
+}

diff --git a/examples/nft-json-file.c b/examples/nft-json-file.c
new file mode 100644 (file)
index 0000000..0c832f2
--- /dev/null
+++ b/examples/nft-json-file.c
@@ -0,0 +1,30 @@
+/* gcc nft-json-file.c -o nft-json-file -lnftables */
+#include <stdlib.h>
+#include <nftables/libnftables.h>
+
+int main(void)
+{
+       struct nft_ctx *ctx;
+       int err;
+
+       ctx = nft_ctx_new(0);
+       if (!ctx) {
+               perror("cannot allocate nft context");
+               return EXIT_FAILURE;
+       }
+
+       nft_ctx_output_set_flags(ctx, NFT_CTX_OUTPUT_JSON);
+
+       /* create ruleset: all commands in the buffer are atomically applied */
+       err = nft_run_cmd_from_filename(ctx, "json-ruleset.nft");
+       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;
+}