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