1 files changed, 66 insertions, 0 deletions
diff --git a/netlink_callbacks.c b/netlink_callbacks.c
new file mode 100644
index 0000000..5e0f34e
--- /dev/null
+++ b/netlink_callbacks.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2012 Daniel Drown <dan-android@drown.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * netlink_callbacks.c - generic callbacks for netlink responses
+ */
+#include <netinet/in.h>
+#include <net/if.h>
+
+#include <linux/rtnetlink.h>
+#include <netlink/handlers.h>
+#include <netlink/msg.h>
+
+/* function: ack_handler
+ * generic netlink callback for ack messages
+ * msg  - netlink message
+ * data - pointer to an int, stores the success code
+ */
+static int ack_handler(struct nl_msg *msg, void *data) {
+  int *retval = data;
+  *retval = 0;
+  return NL_OK;
+}
+
+/* function: error_handler
+ * generic netlink callback for error messages
+ * nla  - error source
+ * err  - netlink error message
+ * arg  - pointer to an int, stores the error code
+ */
+static int error_handler(struct sockaddr_nl *nla, struct nlmsgerr *err, void *arg) {
+  int *retval = arg;
+  if(err->error < 0) {
+    *retval = err->error;
+  } else {
+    *retval = 0; // NLMSG_ERROR used as reply type on no error
+  }
+  return NL_OK;
+}
+
+/* function: alloc_ack_callbacks
+ * allocates a set of netlink callbacks.  returns NULL on failure.  callbacks will modify retval with <0 meaning failure
+ * retval - shared state between caller and callback functions
+ */
+struct nl_cb *alloc_ack_callbacks(int *retval) {
+  struct nl_cb *callbacks;
+
+  callbacks = nl_cb_alloc(NL_CB_DEFAULT);
+  if(!callbacks) {
+    return NULL;
+  }
+  nl_cb_set(callbacks, NL_CB_ACK, NL_CB_CUSTOM, ack_handler, retval);
+  nl_cb_err(callbacks, NL_CB_CUSTOM, error_handler, retval);
+  return callbacks;
+}