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/*
* 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(__attribute__((unused)) 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(__attribute__((unused)) 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;
}
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