1 /*
2  * SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
3  *
4  * SPDX-License-Identifier: Apache-2.0
5  */
6 
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <string.h>
10 #include "esp_log.h"
11 #include "esp_check.h"
12 #include "pcap.h"
13 
14 static const char *TAG = "pcap";
15 
16 #define PCAP_MAGIC_BIG_ENDIAN 0xA1B2C3D4    /*!< Big-Endian */
17 #define PCAP_MAGIC_LITTLE_ENDIAN 0xD4C3B2A1 /*!< Little-Endian */
18 
19 typedef struct pcap_file_t pcap_file_t;
20 
21 /**
22  * @brief Pcap File Header
23  *
24  */
25 typedef struct {
26     uint32_t magic;     /*!< Magic Number */
27     uint16_t major;     /*!< Major Version */
28     uint16_t minor;     /*!< Minor Version */
29     uint32_t zone;      /*!< Time Zone Offset */
30     uint32_t sigfigs;   /*!< Timestamp Accuracy */
31     uint32_t snaplen;   /*!< Max Length to Capture */
32     uint32_t link_type; /*!< Link Layer Type */
33 } pcap_file_header_t;
34 
35 /**
36  * @brief Pcap Packet Header
37  *
38  */
39 typedef struct {
40     uint32_t seconds;        /*!< Number of seconds since January 1st, 1970, 00:00:00 GMT */
41     uint32_t microseconds;   /*!< Number of microseconds when the packet was captured (offset from seconds) */
42     uint32_t capture_length; /*!< Number of bytes of captured data, no longer than packet_length */
43     uint32_t packet_length;  /*!< Actual length of current packet */
44 } pcap_packet_header_t;
45 
46 /**
47  * @brief Pcap Runtime Handle
48  *
49  */
50 struct pcap_file_t {
51     FILE *file;                 /*!< File handle */
52     pcap_link_type_t link_type; /*!< Pcap Link Type */
53     unsigned int major_version; /*!< Pcap version: major */
54     unsigned int minor_version; /*!< Pcap version: minor */
55     unsigned int time_zone;     /*!< Pcap timezone code */
56     uint32_t endian_magic;      /*!< Magic value related to endian format */
57 };
58 
pcap_new_session(const pcap_config_t * config,pcap_file_handle_t * ret_pcap)59 esp_err_t pcap_new_session(const pcap_config_t *config, pcap_file_handle_t *ret_pcap)
60 {
61     esp_err_t ret = ESP_OK;
62     pcap_file_t *pcap = NULL;
63     ESP_GOTO_ON_FALSE(config && ret_pcap, ESP_ERR_INVALID_ARG, err, TAG, "invalid argument");
64     ESP_GOTO_ON_FALSE(config->fp, ESP_ERR_INVALID_ARG, err, TAG, "pcap file handle can't be NULL");
65     pcap = calloc(1, sizeof(pcap_file_t));
66     ESP_GOTO_ON_FALSE(pcap, ESP_ERR_NO_MEM, err, TAG, "no mem for pcap file object");
67     pcap->file = config->fp;
68     pcap->major_version = config->major_version;
69     pcap->minor_version = config->minor_version;
70     pcap->endian_magic = config->flags.little_endian ? PCAP_MAGIC_LITTLE_ENDIAN : PCAP_MAGIC_BIG_ENDIAN;
71     pcap->time_zone = config->time_zone;
72     *ret_pcap = pcap;
73     return ret;
74 err:
75     if (pcap) {
76         free(pcap);
77     }
78     return ret;
79 }
80 
pcap_del_session(pcap_file_handle_t pcap)81 esp_err_t pcap_del_session(pcap_file_handle_t pcap)
82 {
83     ESP_RETURN_ON_FALSE(pcap, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
84     if (pcap->file) {
85         fclose(pcap->file);
86         pcap->file = NULL;
87     }
88     free(pcap);
89     return ESP_OK;
90 }
91 
pcap_write_header(pcap_file_handle_t pcap,pcap_link_type_t link_type)92 esp_err_t pcap_write_header(pcap_file_handle_t pcap, pcap_link_type_t link_type)
93 {
94     ESP_RETURN_ON_FALSE(pcap, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
95     /* Write Pcap File header */
96     pcap_file_header_t header = {
97         .magic = pcap->endian_magic,
98         .major = pcap->major_version,
99         .minor = pcap->minor_version,
100         .zone = pcap->time_zone,
101         .sigfigs = 0,
102         .snaplen = 0x40000,
103         .link_type = link_type,
104     };
105     size_t real_write = fwrite(&header, sizeof(header), 1, pcap->file);
106     ESP_RETURN_ON_FALSE(real_write == 1, ESP_FAIL, TAG, "write pcap file header failed");
107     /* Save the link type to pcap file object */
108     pcap->link_type = link_type;
109     /* Flush content in the buffer into device */
110     fflush(pcap->file);
111     return ESP_OK;
112 }
113 
pcap_capture_packet(pcap_file_handle_t pcap,void * payload,uint32_t length,uint32_t seconds,uint32_t microseconds)114 esp_err_t pcap_capture_packet(pcap_file_handle_t pcap, void *payload, uint32_t length, uint32_t seconds, uint32_t microseconds)
115 {
116     ESP_RETURN_ON_FALSE(pcap && payload, ESP_ERR_INVALID_ARG, TAG, "invalid argumnet");
117     size_t real_write = 0;
118     pcap_packet_header_t header = {
119         .seconds = seconds,
120         .microseconds = microseconds,
121         .capture_length = length,
122         .packet_length = length
123     };
124     real_write = fwrite(&header, sizeof(header), 1, pcap->file);
125     ESP_RETURN_ON_FALSE(real_write == 1, ESP_FAIL, TAG, "write packet header failed");
126     real_write = fwrite(payload, sizeof(uint8_t), length, pcap->file);
127     ESP_RETURN_ON_FALSE(real_write == length, ESP_FAIL, TAG, "write packet payload failed");
128     /* Flush content in the buffer into device */
129     fflush(pcap->file);
130     return ESP_OK;
131 }
132 
pcap_print_summary(pcap_file_handle_t pcap,FILE * print_file)133 esp_err_t pcap_print_summary(pcap_file_handle_t pcap, FILE *print_file)
134 {
135     esp_err_t ret = ESP_OK;
136     long size = 0;
137     char *packet_payload = NULL;
138     ESP_RETURN_ON_FALSE(pcap && print_file, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
139     // get file size
140     fseek(pcap->file, 0L, SEEK_END);
141     size = ftell(pcap->file);
142     fseek(pcap->file, 0L, SEEK_SET);
143     // file empty is allowed, so return ESP_OK
144     ESP_RETURN_ON_FALSE(size, ESP_OK, TAG, "pcap file is empty");
145     // packet index (by bytes)
146     uint32_t index = 0;
147     pcap_file_header_t file_header;
148     size_t real_read = fread(&file_header, sizeof(pcap_file_header_t), 1, pcap->file);
149     ESP_RETURN_ON_FALSE(real_read == 1, ESP_FAIL, TAG, "read pcap file header failed");
150     index += sizeof(pcap_file_header_t);
151     //print pcap header information
152     fprintf(print_file, "------------------------------------------------------------------------\n");
153     fprintf(print_file, "Pcap packet Head:\n");
154     fprintf(print_file, "------------------------------------------------------------------------\n");
155     fprintf(print_file, "Magic Number: %x\n", file_header.magic);
156     fprintf(print_file, "Major Version: %d\n", file_header.major);
157     fprintf(print_file, "Minor Version: %d\n", file_header.minor);
158     fprintf(print_file, "SnapLen: %d\n", file_header.snaplen);
159     fprintf(print_file, "LinkType: %d\n", file_header.link_type);
160     fprintf(print_file, "------------------------------------------------------------------------\n");
161     uint32_t packet_num = 0;
162     pcap_packet_header_t packet_header;
163     while (index < size) {
164         real_read = fread(&packet_header, sizeof(pcap_packet_header_t), 1, pcap->file);
165         ESP_GOTO_ON_FALSE(real_read == 1, ESP_FAIL, err, TAG, "read pcap packet header failed");
166         // print packet header information
167         fprintf(print_file, "Packet %d:\n", packet_num);
168         fprintf(print_file, "Timestamp (Seconds): %d\n", packet_header.seconds);
169         fprintf(print_file, "Timestamp (Microseconds): %d\n", packet_header.microseconds);
170         fprintf(print_file, "Capture Length: %d\n", packet_header.capture_length);
171         fprintf(print_file, "Packet Length: %d\n", packet_header.packet_length);
172         size_t payload_length = packet_header.capture_length;
173         packet_payload = malloc(payload_length);
174         ESP_GOTO_ON_FALSE(packet_payload, ESP_ERR_NO_MEM, err, TAG, "no mem to save packet payload");
175         real_read = fread(packet_payload, payload_length, 1, pcap->file);
176         ESP_GOTO_ON_FALSE(real_read == 1, ESP_FAIL, err, TAG, "read payload error");
177         // print packet information
178         if (file_header.link_type == PCAP_LINK_TYPE_802_11) {
179             // Frame Control Field is coded as LSB first
180             fprintf(print_file, "Frame Type: %2x\n", (packet_payload[0] >> 2) & 0x03);
181             fprintf(print_file, "Frame Subtype: %2x\n", (packet_payload[0] >> 4) & 0x0F);
182             fprintf(print_file, "Destination: ");
183             for (int j = 0; j < 5; j++) {
184                 fprintf(print_file, "%2x ", packet_payload[4 + j]);
185             }
186             fprintf(print_file, "%2x\n", packet_payload[9]);
187             fprintf(print_file, "Source: ");
188             for (int j = 0; j < 5; j++) {
189                 fprintf(print_file, "%2x ", packet_payload[10 + j]);
190             }
191             fprintf(print_file, "%2x\n", packet_payload[15]);
192             fprintf(print_file, "------------------------------------------------------------------------\n");
193         } else if (file_header.link_type == PCAP_LINK_TYPE_ETHERNET){
194             fprintf(print_file, "Destination: ");
195             for (int j = 0; j < 5; j++) {
196                 fprintf(print_file, "%2x ", packet_payload[j]);
197             }
198             fprintf(print_file, "%2x\n", packet_payload[5]);
199             fprintf(print_file, "Source: ");
200             for (int j = 0; j < 5; j++) {
201                 fprintf(print_file, "%2x ", packet_payload[6 + j]);
202             }
203             fprintf(print_file, "%2x\n", packet_payload[11]);
204             fprintf(print_file, "Type: 0x%x\n", packet_payload[13] | (packet_payload[12] << 8));
205             fprintf(print_file, "------------------------------------------------------------------------\n");
206         }
207         else {
208             fprintf(print_file, "Unknown link type:%d\n", file_header.link_type);
209             fprintf(print_file, "------------------------------------------------------------------------\n");
210         }
211         free(packet_payload);
212         packet_payload = NULL;
213         index += packet_header.capture_length + sizeof(pcap_packet_header_t);
214         packet_num ++;
215     }
216     fprintf(print_file, "Pcap packet Number: %d\n", packet_num);
217     fprintf(print_file, "------------------------------------------------------------------------\n");
218     return ret;
219 err:
220     if (packet_payload) {
221         free(packet_payload);
222     }
223     return ret;
224 }
225