esp-idf/examples/wifi/simple_sniffer/components/pcap/pcap.c

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// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
//
// 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/unistd.h>
#include <sys/fcntl.h>
#include "esp_types.h"
#include "esp_err.h"
#include "esp_log.h"
#include "pcap.h"
static const char *PCAP_TAG = "pcap";
#define PCAP_CHECK(a, str, goto_tag, ...) \
do \
{ \
if (!(a)) \
{ \
ESP_LOGE(PCAP_TAG, "%s(%d): " str, __FUNCTION__, __LINE__, ##__VA_ARGS__); \
goto goto_tag; \
} \
} while (0)
/**
* @brief Pcap File Header
*
*/
typedef struct {
uint32_t magic; /*!< Magic Number */
uint16_t major; /*!< Major Version */
uint16_t minor; /*!< Minor Version */
uint32_t zone; /*!< Time Zone Offset */
uint32_t sigfigs; /*!< Timestamp Accuracy */
uint32_t snaplen; /*!< Max Length to Capture */
uint32_t link_type; /*!< Link Layer Type */
} pcap_file_header_t;
/**
* @brief Pcap Packet Header
*
*/
typedef struct {
uint32_t seconds; /*!< Number of seconds since January 1st, 1970, 00:00:00 GMT */
uint32_t microseconds; /*!< Number of microseconds when the packet was captured (offset from seconds) */
uint32_t capture_length; /*!< Number of bytes of captured data, no longer than packet_length */
uint32_t packet_length; /*!< Actual length of current packet */
} pcap_packet_header_t;
/**
* @brief Pcap Runtime Handle
*
*/
typedef struct {
FILE *file; /*!< File handle */
} pcap_runtime_t;
esp_err_t pcap_capture_packet(pcap_handle_t handle, void *payload, uint32_t length, uint32_t seconds, uint32_t microseconds)
{
PCAP_CHECK(handle, "pcap handle is NULL", err);
pcap_runtime_t *pcap_rt = (pcap_runtime_t *)handle;
PCAP_CHECK(pcap_rt->file, "pcap file is NULL", err);
size_t real_write = 0;
pcap_packet_header_t header = {
.seconds = seconds,
.microseconds = microseconds,
.capture_length = length,
.packet_length = length
};
real_write = fwrite(&header, sizeof(header), 1, pcap_rt->file);
PCAP_CHECK(real_write == 1, "write packet header error", err);
real_write = fwrite(payload, sizeof(uint8_t), length, pcap_rt->file);
PCAP_CHECK(real_write == length, "write packet payload error", err);
/* Flush content in the buffer into device */
fflush(pcap_rt->file);
return ESP_OK;
err:
return ESP_FAIL;
}
esp_err_t pcap_deinit(pcap_handle_t handle)
{
PCAP_CHECK(handle, "pcap handle is NULL", err);
pcap_runtime_t *pcap_rt = (pcap_runtime_t *)handle;
PCAP_CHECK(pcap_rt->file, "pcap file is NULL", err);
PCAP_CHECK(fclose(pcap_rt->file) == 0, "close pcap file failed", err);
pcap_rt->file = NULL;
free(pcap_rt);
ESP_LOGD(PCAP_TAG, "pcap deinit OK");
return ESP_OK;
err:
ESP_LOGW(PCAP_TAG, "pcap deinit failed");
return ESP_FAIL;
}
esp_err_t pcap_init(pcap_config_t *config, pcap_handle_t *handle)
{
PCAP_CHECK(config, "config is NULL", err);
PCAP_CHECK(handle, "pcap handle is NULL", err);
pcap_runtime_t *pcap_rt = calloc(sizeof(pcap_runtime_t), 1);
PCAP_CHECK(pcap_rt, "calloc pcap runtime failed", err);
pcap_rt->file = config->fp;
/* Write Pcap File header */
pcap_file_header_t header = {
.magic = PCAP_MAGIC_BIG_ENDIAN,
.major = PCAP_VERSION_MAJOR,
.minor = PCAP_VERSION_MINOR,
.zone = PCAP_TIME_ZONE_GMT,
.sigfigs = 0,
.snaplen = 0x40000,
.link_type = config->link_type
};
size_t real_write = fwrite(&header, sizeof(header), 1, pcap_rt->file);
PCAP_CHECK(real_write == 1, "write pcap file header failed", err_write);
/* Flush content in the buffer into device */
fflush(pcap_rt->file);
*handle = (pcap_handle_t)pcap_rt;
ESP_LOGD(PCAP_TAG, "pcap init OK");
return ESP_OK;
/* Error Handling */
err_write:
fclose(pcap_rt->file);
pcap_rt->file = NULL;
free(pcap_rt);
err:
ESP_LOGW(PCAP_TAG, "pcap init failed");
return ESP_FAIL;
}