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wifimon.c
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wifimon.c
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/* WIFIMON - wifi monitor, analyzer, utility tool */
/* Authors: Daniele Paolini -> [email protected] */
/* Lorenzo Vannucci -> [email protected] */
/* Marco Venturini -> [email protected] */
/* To compile: gcc wifimon.c -o wifimon -lpcap -Wall -pedantic */
/* Run as root! Please set your network device in monitor mode! */
/* */
/* This code is distributed under the GPL License. For more info check: */
/* http://www.gnu.org/copyleft/gpl.html */
#include <pcap.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <time.h>
#include <sys/time.h>
#include <ctype.h>
#include <netinet/ether.h>
#include <signal.h>
#include <float.h>
#define FILTER "type mgt subtype beacon" /*beacon frame filter*/
/* TYPE DEFINITIONS */
typedef struct _access_point{
unsigned char *mac_address; /*mac address of the ap*/
float ssi_signal_temp_sum, /*temporary signals sum*/
data_rate_temp_sum, /*temporary rates sum*/
data_rate_min, /*minimum data rate*/
data_rate_max, /*maximum data rate*/
data_rate_sum, /*data rates sum*/
ssi_signal_min, /*minimum ssi signal*/
ssi_signal_sum, /*signals sum*/
ssi_signal_max, /*maximum ssi signal*/
tap_counter_temp;
time_t data_rate_min_ts, /*arrival time of minimum data rate*/
data_rate_max_ts, /*arrival time of maximum data rate*/
ssi_signal_max_ts, /*arrival time of maximum ssi signal*/
ssi_signal_min_ts; /*arrival time of minimum ssi signal*/
int tap_counter, /*tap counter*/
channel; /*channel*/
struct _access_point *next; /*pointer at next element in list*/
} access_point; /*stores all info about an access point*/
typedef struct _ssid{
char* ssid_name;
int num_ap;
access_point *list_ap;
struct _ssid *next; /*stores all info about a ssid*/
} ssid;
/* GLOBAL VARIABLES */
pcap_t *descr; /*pcap handler descriptor*/
static volatile sig_atomic_t signal_flag; /*represent incoming SIGINT signal*/
static int packet_count; /*pkt info*/
int ssid_len, /*pkt info*/
live, /*if it's set, live mode will be activated*/
json_flag, /*if it's set, json report will be written*/
write_log; /*if it's set, a log file will be written*/
u_int16_t radiotap_len; /*pkt info*/
int8_t ssi_signal; /*pkt info*/
float data_rate; /*pkt info*/
time_t in_time; /*used for managing timestamp*/
struct tm *time_now; /*used for managing timestamp*/
char tmbuf[64], /*used for managing timestamp*/
buf[64]; /*used for managing timestamp*/
FILE *out, /*output file descriptor*/
*json; /*json report file descriptor*/
ssid *ssid_list; /*list of ssid*/
/* FUNCTIONS DEFINITION - see implementation below the main function */
static void print_usage();
static void print_help();
static void packet_callback(u_char *args, const struct pcap_pkthdr *header, const u_char *packet);
static void sigint_handler();
static ssid* add_ssid(char* name, ssid *list);
static ssid* search_ssid(char* name, ssid *list);
static access_point* add_ap(unsigned char* mac, access_point* list);
static access_point* search_ap(unsigned char* mac, access_point* list);
static void update(float signal, float rate, time_t ts, int channel, access_point* ap);
static int mac_compare(unsigned char* a, unsigned char* b);
static void print_mac(unsigned char* data, FILE* file_desc);
int select_channel(u_int16_t frequency);
/* MAIN FUNCTION */
int main(int argc, char* argv[]){
int opt;
char *output_file = NULL,
*input_file = NULL,
*device = NULL;
char error_buffer[PCAP_ERRBUF_SIZE];
const u_char *packet;
pcap_if_t *devpointer = NULL;
bpf_u_int32 mask; /*my net mask*/
bpf_u_int32 net; /*my ip address*/
struct in_addr address;
struct bpf_program compiled_filter;
struct pcap_pkthdr *header;
struct sigaction sigint_action; /* struct for signal registration */
sigset_t new_set, /* signal mask */
old_set; /* signal mask */
ssid *ssid_iterator;
access_point *ap_iterator;
struct tm *time_now;
char tmbuf[64], buf1[64], buf2[64], buf3[64], buf4[64];
memset(error_buffer, 0, PCAP_ERRBUF_SIZE);
(void)header; /*get rid of the 'unused variable warning' superfluous in this case*/
(void)packet; /*get rid of the 'unused variable warning' superfluous in this case*/
packet_count = 0;
signal_flag = 0;
write_log = 0;
live = 0;
descr = NULL;
ssid_list = NULL;
/* parsing command line */
while((opt=getopt(argc, argv, "jhl:do:i:")) != -1){
switch(opt){
case 'h': /* printing help message */
print_help(argv[0]);
return(EXIT_SUCCESS);
break;
case 'd': /* printing all availables devices */
if(pcap_findalldevs(&devpointer, error_buffer) == 0) {
int i = 0;
fprintf(stdout,"Available devices:\n");
while(devpointer) {
printf(" %d. %s\n", i++, devpointer->name);
devpointer = devpointer->next;
}
}
fprintf(stdout,"\n\n\n");
return(EXIT_FAILURE);
case 'o': /* saving a log file - parameter needed */
output_file = malloc((strlen(optarg) + 1)*sizeof(*output_file));
if(output_file== NULL){
fprintf(stderr,"SEVERE ERROR: memory allocation fail\n");
return(EXIT_FAILURE);
}
snprintf(output_file,strlen(optarg) + 1,"%s",optarg);
write_log = 1;
break;
case 'i': /* reading an input file - parameter needed */
input_file = malloc((strlen(optarg) + 1)*sizeof(*input_file));
if(input_file == NULL){
fprintf(stderr,"SEVERE ERROR: memory allocation fail\n");
return(EXIT_FAILURE);
}
snprintf(input_file,strlen(optarg) + 1,"%s",optarg);
break;
case 'l': /* reading the device name - parameter needed */
live = 1;
device = malloc((strlen(optarg) + 1)*sizeof(*device));
if(device == NULL){
fprintf(stderr,"SEVERE ERROR: memory allocation fail\n");
return(EXIT_FAILURE);
}
snprintf(device,strlen(optarg) + 1,"%s",optarg);
break;
case 'j': /* json report */
json_flag = 1;
json = fopen("report.json","w");
break;
default: /* wrong option management */
print_help(argv[0]);
return(EXIT_FAILURE);
}
}
/* checking parameter */
if(write_log){
/* write log file option */
if(output_file == NULL){
fprintf(stderr,"ERROR: You must select an output file\n");
print_help(argv[0]);
return(EXIT_FAILURE);
}
if(access(output_file, F_OK | W_OK | X_OK) == -1){
fprintf(stderr,"ERROR: You must select a valid output file\n");
print_help(argv[0]);
return(EXIT_FAILURE);
}
out = fopen(output_file,"w");
}
fprintf(stdout,"\nWIFIMON - wifi monitoring tool\n\n");
fprintf(stdout," @ This software will scan the air to monitor all the access points near to you");
fprintf(stdout," and display relevant info about them.\n");
fprintf(stdout," @ This open source software is released under GPL licence and provided without any warranty.\n");
fprintf(stdout," @ The sniffed packets will not be analyzed to infringe your privacy.\n");
fprintf(stdout," @ Use and modify at your own risk.\n\n\n");
if(live){
/* setting signal mask */
if(sigfillset(&new_set) == -1){
perror("ERROR: Cannot set signal mask, ");
return(EXIT_FAILURE);
}
/* masking all signals during SIGINT handler installation */
if(sigprocmask(SIG_SETMASK, &new_set, &old_set) == -1){
perror("ERROR: Cannot set process's signal mask, ");
return(EXIT_FAILURE);
}
/* registering SIGINT handler */
memset(&sigint_action,'\0',sizeof(sigint_action));
sigint_action.sa_handler = &sigint_handler;
sigint_action.sa_flags = SA_RESTART;
if(sigaction(SIGINT, &sigint_action, NULL) == -1){
perror("ERROR: Cannot install handler for [SIGINT], ");
return(EXIT_FAILURE);
}
/* unmasking signals */
if(sigprocmask(SIG_SETMASK, &old_set, NULL) == -1){
perror("ERROR: Cannot restore process's signal mask, ");
return(EXIT_FAILURE);
}
/* live mode ON */
fprintf(stdout,"Live capture mode: ON\n");
/* checking parameter */
if(device == NULL){
fprintf(stderr,"ERROR: You must select a device file in order to work offline\n");
fprintf(stderr,"NOTE: Use -d option as root to see the list of all available devices\n");
print_usage(argv[0]);
return(EXIT_FAILURE);
}
/* looking up for my netmask and my ip address */
if (pcap_lookupnet(device, &net, &mask, error_buffer) == -1) {
fprintf(stderr, "ERROR: Can't get netmask for device %s\n", device);
net = 0;
mask = 0;
return(EXIT_FAILURE);
}
/* printing info */
address.s_addr = mask;
fprintf(stdout,"Monitor Mask: %s\n",inet_ntoa(address));
address.s_addr = net;
fprintf(stdout,"Monitor IP: %s\n\n",inet_ntoa(address));
/* opening device in promiscuos mode with 1 second timeout - BUFSIZ is in pcap.h */
if((descr = pcap_open_live(device, BUFSIZ, 1, 1000, error_buffer)) == NULL){
fprintf(stderr, "ERROR: %s\n", error_buffer);
return(EXIT_FAILURE);
}
/* setting beacon filter */
if (pcap_compile(descr, &compiled_filter, FILTER, 1, net) == -1) {
fprintf(stderr, "ERROR: Couldn't parse filter %s: %s\n", FILTER, pcap_geterr(descr));
return(EXIT_FAILURE);
}
/* applying beacon filter */
if (pcap_setfilter(descr, &compiled_filter) == -1) {
fprintf(stderr, "ERROR: Couldn't apply filter %s: %s\n", FILTER, pcap_geterr(descr));
return(EXIT_FAILURE);
}
fprintf(stdout, "Monitoring in progress...\n\n");
fprintf(stdout, "Press [ctrl+c] or send [SIGINT] to this process [pid:%d] to exit and ",getpid());
fprintf(stdout,"display statistics\n\n");
/* pcap loop */
if (pcap_loop(descr, -1, packet_callback, NULL) == -1){
fprintf(stderr, "ERROR: Pcap loop error: %s\n", pcap_geterr(descr));
}
/* freeing the heap */
free(device);
} else{
/* live mode OFF */
fprintf(stdout,"Live capture mode: OFF\n");
/* checking parameter */
if(input_file == NULL){
fprintf(stderr,"ERROR: You must select an input file in order to work offline\n");
print_usage(argv[0]);
return(EXIT_FAILURE);
}
/* opening pcap file */
if((descr = pcap_open_offline(input_file, error_buffer)) == NULL){
fprintf(stderr, "ERROR: %s\n", error_buffer);
return(EXIT_FAILURE);
}
/* setting beacon filter */
if (pcap_compile(descr, &compiled_filter, FILTER, 1, net) == -1) {
fprintf(stderr, "ERROR: Couldn't parse filter %s: %s\n", FILTER, pcap_geterr(descr));
return(EXIT_FAILURE);
}
/* applying beacon filter */
if (pcap_setfilter(descr, &compiled_filter) == -1) {
fprintf(stderr, "ERROR: Couldn't apply filter %s: %s\n", FILTER, pcap_geterr(descr));
return(EXIT_FAILURE);
}
/* reading packets in the pcap file */
if (pcap_loop(descr, -1, packet_callback, NULL) < 0){
fprintf(stderr, "ERROR: Pcap loop error: %s\n", pcap_geterr(descr));
}
/* freeing the heap */
free(input_file);
}
/*printing final statistics*/
fprintf(stdout,"\n\nFinal statistics:\n");
ssid_iterator = ssid_list;
while(ssid_iterator != NULL){
fprintf(stdout,"[SSID] name: %s / number of access points: %d\n",ssid_iterator->ssid_name,
ssid_iterator->num_ap);
if(json_flag){
fprintf(json,"{ \"ssid\": {\n");
fprintf(json," \"name\": \"%s\",\n",ssid_iterator->ssid_name);
fprintf(json," \"number of access point\": \"%d\",\n",ssid_iterator->num_ap);
fprintf(json," \"aplist\": {\n");
fprintf(json," \"ap\": [\n");
}
ap_iterator = ssid_iterator->list_ap;
while(ap_iterator != NULL){
fprintf(stdout," [AP] mac: ");
print_mac(ap_iterator->mac_address,stdout);
fprintf(stdout,"\n");
fprintf(stdout," data rate avg: %f Mbps\n", (float)(ap_iterator->data_rate_sum / (float)ap_iterator->tap_counter));
fprintf(stdout," signal avg: %f Dbm\n", (float)(ap_iterator->ssi_signal_sum / (float)ap_iterator->tap_counter));
fprintf(stdout," channel: %d\n",ap_iterator->channel);
fprintf(stdout," max data rate %f Mbps\n",ap_iterator->data_rate_max);
time_now = localtime(&ap_iterator->data_rate_max_ts);
strftime(tmbuf, sizeof(tmbuf), "%Y-%m-%d %H:%M:%S", time_now);
snprintf(buf1, sizeof(buf1), "%s", tmbuf);
fprintf(stdout," at time: %s\n",buf1);
fprintf(stdout," min data rate %f Mbps\n",ap_iterator->data_rate_min);
time_now = localtime(&ap_iterator->data_rate_min_ts);
strftime(tmbuf, sizeof(tmbuf), "%Y-%m-%d %H:%M:%S", time_now);
snprintf(buf2, sizeof(buf2), "%s", tmbuf);
fprintf(stdout," at time: %s\n",buf2);
fprintf(stdout," max ssi signal %f Dbm\n",ap_iterator->ssi_signal_max);
time_now = localtime(&ap_iterator->ssi_signal_max_ts);
strftime(tmbuf, sizeof(tmbuf), "%Y-%m-%d %H:%M:%S", time_now);
snprintf(buf3, sizeof(buf3), "%s", tmbuf);
fprintf(stdout," at time: %s\n",buf3);
fprintf(stdout," min ssi signal %f Dbm\n",ap_iterator->ssi_signal_min);
time_now = localtime(&ap_iterator->ssi_signal_min_ts);
strftime(tmbuf, sizeof(tmbuf), "%Y-%m-%d %H:%M:%S", time_now);
snprintf(buf4, sizeof(buf4), "%s", tmbuf);
fprintf(stdout," at time: %s\n",buf4);
if(json_flag){
fprintf(json," {\"mac\": \"");
print_mac(ap_iterator->mac_address,json);
fprintf(json,"\",\n \"data rate\":\"%f\",\n \"signal\": \"%f\",\n \"channel\":\"%d\",\n \"max data rate\": \"%f\",\n \"max data rate time\": \"%s\",\n \"min data rate\": \"%f\",\n \"min data rate time\": \"%s\",\n \"max signal\": \"%f\",\n \"max signal time\": \"%s\",\n \"min signal\": \"%f\",\n \"min signal time\": \"%s\"},\n",
(float)(ap_iterator->data_rate_temp_sum / (float)ap_iterator->tap_counter_temp),
(float)(ap_iterator->ssi_signal_temp_sum / (float)ap_iterator->tap_counter_temp),
ap_iterator->channel,
ap_iterator->data_rate_max,
buf1,
ap_iterator->data_rate_min,
buf2,
ap_iterator->ssi_signal_max,
buf3,
ap_iterator->ssi_signal_min,
buf4
);
}
ap_iterator = ap_iterator->next;
}
fprintf(stdout,"\n");
if(json_flag)
fprintf(json,"\b ]}\n }\n}\n");
ssid_iterator = ssid_iterator->next;
}
fprintf(stdout,"\n\n");
/* closing pcap handler descriptor and freeing heap */
pcap_close(descr);
if(write_log){
free(output_file);
fclose(out);
}
if(json_flag)
fclose(json);
return(EXIT_SUCCESS);
}
/* FUNCTIONS IMPLEMENTATION */
/* prints usage message*/
static void print_usage(char* s){
fprintf(stdout,"Usage: %s [OPTIONS] [PARAMETERS]\n",s);
fprintf(stdout,"NOTE: in order to work properly you must run this program as root and your\nnetwork interface must");
fprintf(stdout," work in monitor mode.\n");
}
/* prints help message*/
static void print_help(char* s){
print_usage(s);
fprintf(stdout,"Option list:\n -l live mode: needs a parameter, capture packets directly from the\n");
fprintf(stdout," network interface passed as a parameter\n");
fprintf(stdout," -d device list: display all network devices availables on this machine\n");
fprintf(stdout," and exit\n");
fprintf(stdout," -i input file: needs a parameter, [mandatory] if live mode is off,\n");
fprintf(stdout," specifies the file from which to read the packets\n");
fprintf(stdout," [pcap compatible format is needed]\n");
fprintf(stdout," -o output file: needs a parameter, specifies where to save the log file\n");
fprintf(stdout," of all packets\n");
fprintf(stdout," -j json report: prints the report of the monitoring in json format into\n");
fprintf(stdout," a file named 'report.json'\n");
fprintf(stdout," -h help: display this help message\n");
}
/* forces 'packet_callback()' to terminate */
static void sigint_handler(){
signal_flag = 1;
}
/* manages incoming beacon frames */
static void packet_callback(u_char *args, const struct pcap_pkthdr *header, const u_char *packet){
int x, ssid_len, channel;
u_int16_t radiotap_len, channel_frequency=0;
u_int8_t c1=0, c2=0;
float ssi_signal, data_rate;
time_t time;
struct tm *time_now;
char tmbuf[64], buf[64];
unsigned char *temp_mac = NULL;
char* temp_ssid = NULL;
ssid* temp_ssid_address = NULL, *ssid_iterator = NULL;
access_point* temp_ap_address = NULL, *ap_iterator = NULL;
if(signal_flag){
/* incoming SIGINT, forcing termination */
pcap_breakloop(descr);
}
packet_count ++;
/*retrieving initial info*/
time = header->ts.tv_sec;
time_now = localtime(&time);
strftime(tmbuf, sizeof(tmbuf), "%Y-%m-%d %H:%M:%S", time_now);
snprintf(buf, sizeof(buf), "%s.%06d", tmbuf, (int) header->ts.tv_usec);
radiotap_len = (u_int16_t) *(packet + 2);
temp_mac = malloc((sizeof(unsigned char)*6) + 1);
if(temp_mac == NULL){
fprintf(stderr,"SEVERE ERROR: memory allocation fail\n");
exit(EXIT_FAILURE);
}
ssid_len = (u_int8_t) packet[radiotap_len + 37];
temp_ssid = malloc((ssid_len+1)*sizeof(*temp_ssid));
if(temp_ssid == NULL){
fprintf(stderr,"SEVERE ERROR: memory allocation fail\n");
exit(EXIT_FAILURE);
}
for(x=0;x<ssid_len;x++)
*(temp_ssid + x) = (char) *(packet + radiotap_len + 38 + x);
*(temp_ssid + x) = '\0';
if(write_log){
/* printing intial info*/
fprintf(out,"==================================================\n");
fprintf(out,"Reading packet %d#\n", packet_count);
fprintf(out,"Packet size : %d\n", header->len);
fprintf(out,"Packet timestamp : %s\n", buf);
fprintf(out,"AP SSID: %s\n",temp_ssid);
}
/* retrieving other info */
switch(radiotap_len){
case 18 :{
for(x=0;x<6;x++)
temp_mac[x] = (unsigned char) *(packet + 18 + 16 + x);
temp_mac[x] = '\0';
ssi_signal = (int8_t) *(packet + 14);
data_rate = (float) *(packet + 9) / 2.0 ;
c1 = *(packet + 10);
c2 = *(packet + 11);
channel_frequency = (c2 << 8) + c1;
break;
}
case 25 :{
for(x=0;x<6;x++)
temp_mac[x] = (unsigned char) *(packet + 25 + 16 + x);
temp_mac[x] = '\0';
ssi_signal = (int8_t) *(packet + 22);
data_rate = (float) *(packet + 17) / 2.0 ;
c1 = *(packet + 18);
c2 = *(packet + 19);
channel_frequency = (c2 << 8) + c1;
break;
}
case 26 :{
for(x=0;x<6;x++)
temp_mac[x] = (unsigned char) *(packet + 25 + 16 + x);
temp_mac[x] = '\0';
ssi_signal = (int8_t) *(packet + 22);
data_rate = (float) *(packet + 17) / 2.0 ;
c1 = *(packet + 18);
c2 = *(packet + 19);
channel_frequency = (c2 << 8) + c1;
break;
}
case 30 :{
for(x=0;x<6;x++)
temp_mac[x] = (unsigned char) *(packet + 25 + 16 + x);
temp_mac[x] = '\0';
ssi_signal = (int8_t) *(packet + 22);
data_rate = (float) *(packet + 17) / 2.0 ;
c1 = *(packet + 18);
c2 = *(packet + 19);
channel_frequency = (c2 << 8) + c1;
break;
}
case 36 :{
for(x=0;x<6;x++)
temp_mac[x] = (unsigned char) *(packet + 36 + 16 + x);
temp_mac[x] = '\0';
ssi_signal = (int8_t) *(packet + 34);
data_rate = (float) *(packet + 25) / 2.0 ;
c1 = *(packet + 26);
c2 = *(packet + 27);
channel_frequency = (c2 << 8) + c1;
break;
}
default :{
fprintf(stdout, "WARNING: This network interface it's not yet supported, results may be incorrect\n");
for(x=0;x<6;x++)
temp_mac[x] = (unsigned char) *(packet + 36 + 16 + x);
temp_mac[x] = '\0';
ssi_signal = (int8_t) *(packet + 34);
data_rate = (float) *(packet + 25) / 2.0 ;
c1 = *(packet + 26);
c2 = *(packet + 27);
channel_frequency = (c2 << 8) + c1;
}
}
if(write_log){
/* printing other info */
fprintf(out,"AP address : ");
print_mac(temp_mac,out);
fprintf(out,"\n");
fprintf(out,"SSI signal : %d Dbm\n", (int) ssi_signal);
fprintf(out,"Data rate : %f Mb/s\n", (float) data_rate);
fprintf(out,"==================================================\n");
}
channel = select_channel(channel_frequency);
temp_ssid_address = search_ssid(temp_ssid, ssid_list);
if(temp_ssid_address != NULL){
/* previously stored ssid */
temp_ap_address = search_ap(temp_mac, temp_ssid_address->list_ap);
if(temp_ap_address != NULL){
/* previously stored ap */
update(ssi_signal, data_rate, time, channel, temp_ap_address);
} else{
/* new ap */
temp_ssid_address->list_ap = add_ap(temp_mac, temp_ssid_address->list_ap);
update(ssi_signal, data_rate, time, channel, temp_ap_address);
temp_ssid_address->num_ap ++;
}
} else{
/* new ssid */
ssid_list = add_ssid(temp_ssid, ssid_list);
ssid_list->list_ap = add_ap(temp_mac, ssid_list->list_ap);
ssid_list->num_ap ++;
update(ssi_signal, data_rate, time, channel, ssid_list->list_ap);
}
if(live){
/* printing temporary statistics every 100 packets */
ssid_iterator = ssid_list;
if(packet_count%100 == 0 && ssid_iterator != NULL){
fprintf(stdout,"Temporary statistics:\n\n");
while(ssid_iterator != NULL){
fprintf(stdout,"[SSID] name: %s / number of access points: %d\n",ssid_iterator->ssid_name,
ssid_iterator->num_ap);
ap_iterator = ssid_iterator->list_ap;
while(ap_iterator != NULL){
if(ap_iterator->tap_counter_temp > 0){
/* if tap_counter_temp == 0 we've temporary lost the connection with ap, so not print it */
fprintf(stdout," [AP] mac: ");
print_mac(ap_iterator->mac_address,stdout);
fprintf(stdout," / data rate: %f Mbps / signal: %f Dbm / channel: %d\n",
(float)(ap_iterator->data_rate_temp_sum / (float)ap_iterator->tap_counter_temp),
(float)(ap_iterator->ssi_signal_temp_sum / (float)ap_iterator->tap_counter_temp),
channel);
/* resetting counters */
ap_iterator->tap_counter_temp= 0;
ap_iterator->data_rate_temp_sum = 0;
ap_iterator->ssi_signal_temp_sum = 0;
}
ap_iterator = ap_iterator->next;
}
fprintf(stdout,"\n");
ssid_iterator = ssid_iterator->next;
}
fprintf(stdout,"\n\n");
}
}
}
/* returns the pointer at the structure that contains 'name' if it's in the list, NULL otherwise */
static ssid* search_ssid(char* name, ssid *list){
ssid* this = list;
while(this != NULL){
if(strcmp(this->ssid_name, name) == 0)
return this;
this = this->next;
}
return NULL;
}
/* returns the new list obtained by adding name on top of the list */
static ssid* add_ssid(char* name, ssid *list){
ssid *new_ssid = malloc(sizeof(ssid));
if(new_ssid == NULL){
fprintf(stderr,"SEVERE ERROR: memory allocation fail\n");
exit(EXIT_FAILURE);
}
new_ssid->ssid_name = name;
new_ssid->list_ap = NULL;
new_ssid->num_ap = 0;
new_ssid->next = list;
return new_ssid;
}
/* returns the pointer at the structure contains 'mac' if it's present in the list, NULL otherwise */
static access_point* search_ap(unsigned char* mac, access_point* list){
access_point* this = list;
while(this != NULL){
if(mac_compare(this->mac_address,mac)==0)
return this;
this = this->next;
}
return NULL;
}
/* returns the new list obtained by adding 'mac' on top of the list */
static access_point* add_ap(unsigned char* mac, access_point* list){
access_point *new_ap = malloc(sizeof(access_point));
if(new_ap == NULL){
fprintf(stderr,"SEVERE ERROR: memory allocation fail\n");
exit(EXIT_FAILURE);
}
new_ap->mac_address = mac;
new_ap->ssi_signal_sum = 0;
new_ap->ssi_signal_temp_sum = 0;
new_ap->data_rate_temp_sum = 0;
new_ap->tap_counter_temp = 0;
new_ap->data_rate_sum = 0;
new_ap->data_rate_min = FLT_MAX;
new_ap->data_rate_max = FLT_MIN;
new_ap->ssi_signal_max = -500.0;
new_ap->ssi_signal_min = FLT_MAX;
new_ap->data_rate_min_ts = 0;
new_ap->data_rate_max_ts = 0;
new_ap->ssi_signal_max_ts = 0;
new_ap->ssi_signal_min_ts = 0;
new_ap->tap_counter = 0;
new_ap->channel = 0;
new_ap->next = list;
return new_ap;
}
/* updates statistics of the ap */
static void update(float signal, float rate, time_t ts, int channel, access_point* ap){
if(ap != NULL){
ap->tap_counter ++;
ap->tap_counter_temp ++;
ap->ssi_signal_sum += signal;
ap->ssi_signal_temp_sum += signal;
ap->data_rate_sum += rate;
ap->data_rate_temp_sum += rate;
if(signal < ap->ssi_signal_min){
ap->ssi_signal_min = signal;
ap->ssi_signal_min_ts = ts;
}
if(signal > ap->ssi_signal_max){
ap->ssi_signal_max = signal;
ap->ssi_signal_max_ts = ts;
}
if(rate < ap->data_rate_min){
ap->data_rate_min = rate;
ap->data_rate_min_ts = ts;
}
if(rate > ap->data_rate_max){
ap->data_rate_max = rate;
ap->data_rate_max_ts = ts;
}
ap->channel = channel;
}
}
/* compares two mac address */
int mac_compare(unsigned char *a, unsigned char *b){
int i=0, bol=0;
while(*(a+i)!='\0' && *(b+i)!='\0' && bol==0){
if(*(a+i) != *(b+i))
bol=1;
i++;
}
return bol;
}
/* print mac address on stdout */
void print_mac(unsigned char* data, FILE* file_desc){
fprintf(file_desc, "%-.2X:%-.2X:%-.2X:%-.2X:%-.2X:%-.2X", data[0], data[1], data[2], data[3], data[4], data[5]);
}
/* returns correct channel corresponding at 'frequency', 0 if not supported */
int select_channel(u_int16_t frequency){
switch(frequency){
case 2412:
return 1;
case 2417:
return 2;
case 2422:
return 3;
case 2427:
return 4;
case 2432:
return 5;
case 2437:
return 6;
case 2442:
return 7;
case 2447:
return 8;
case 2452:
return 9;
case 2457:
return 10;
case 2462:
return 11;
case 2467:
return 12;
case 2472:
return 13;
case 2484:
return 14;
}
return 0;
}