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/* Copyright 2021 The libwifi Authors
*
* 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.
*/
#include "probe_request.h"
#include "../../core/misc/byteswap.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
/**
* The length of a probe request frame is the sum of the header length plus the tagged parameters length.
*/
size_t libwifi_get_probe_req_length(struct libwifi_probe_req *probe_req) {
return sizeof(struct libwifi_mgmt_unordered_frame_header) + probe_req->tags.length;
}
/**
* The generated probe request frame is made with sane defaults defined in common.h.
* Two tagged parameters are also added to the beacon: SSID and Channel.
*/
int libwifi_create_probe_req(struct libwifi_probe_req *probe_req, const unsigned char receiver[6],
const unsigned char transmitter[6], const unsigned char bssid[6],
const char *ssid, uint8_t channel) {
memset(probe_req, 0, sizeof(struct libwifi_probe_req));
probe_req->frame_header.frame_control.type = TYPE_MANAGEMENT;
probe_req->frame_header.frame_control.subtype = SUBTYPE_PROBE_REQ;
memcpy(&probe_req->frame_header.addr1, receiver, 6);
memcpy(&probe_req->frame_header.addr2, transmitter, 6);
memcpy(&probe_req->frame_header.addr3, bssid, 6);
probe_req->frame_header.seq_control.sequence_number = (rand() % 4096);
int ret = libwifi_quick_add_tag(&probe_req->tags, TAG_SSID, (const unsigned char *) ssid, strlen(ssid));
if (ret != 0) {
return ret;
}
ret = libwifi_quick_add_tag(&probe_req->tags, TAG_DS_PARAMETER, (const unsigned char *) &channel, 1);
return ret;
}
/**
* Copy a libwifi_probe_req into a regular unsigned char buffer. This is useful when injecting generated
* libwifi frames.
*/
size_t libwifi_dump_probe_req(struct libwifi_probe_req *probe_req, unsigned char *buf, size_t buf_len) {
size_t probe_req_len = libwifi_get_probe_req_length(probe_req);
if (probe_req_len > buf_len) {
return -EINVAL;
}
size_t offset = 0;
memcpy(buf + offset, &probe_req->frame_header, sizeof(struct libwifi_mgmt_unordered_frame_header));
offset += sizeof(struct libwifi_mgmt_unordered_frame_header);
memcpy(buf + offset, probe_req->tags.parameters, probe_req->tags.length);
offset += probe_req->tags.length;
return probe_req_len;
}
/**
* Because the tagged parameters memory is managed inside of the library, the library must
* be the one to free it, too.
*/
void libwifi_free_probe_req(struct libwifi_probe_req *probe_req) {
free(probe_req->tags.parameters);
}
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