ubuntu1804 wifi搜网 C程序

以下是一个简单的C程序，用于扫描和连接wifi网络。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <errno.h>
#include <time.h>

#define MAX_SSID_LEN 32
#define MAX_BSS_LEN 18

typedef struct {
    char ssid[MAX_SSID_LEN];
    char bssid[MAX_BSS_LEN];
    int signal;
} wifi_ap_t;

wifi_ap_t *wifi_scan() {
    wifi_ap_t *aps = NULL;
    int sock, i;
    struct iwreq wrq;
    char *buffer = NULL;
    int buflen = IW_SCAN_MAX_DATA;
    int ap_count = 0;

    // Open a socket
    sock = socket(AF_INET, SOCK_DGRAM, 0);
    if (sock == -1) {
        perror("socket");
        return NULL;
    }

    // Allocate memory for the buffer
    buffer = malloc(buflen);
    if (!buffer) {
        perror("malloc");
        close(sock);
        return NULL;
    }

    memset(&wrq, 0, sizeof(struct iwreq));
    strncpy(wrq.ifr_name, "wlan0", IFNAMSIZ);

    wrq.u.data.pointer = buffer;
    wrq.u.data.length = buflen;
    wrq.u.data.flags = 0;

    // Issue the SCAN request
    if (ioctl(sock, SIOCSIWSCAN, &wrq) == -1) {
        perror("ioctl[SIOCSIWSCAN]");
        free(buffer);
        close(sock);
        return NULL;
    }

    // Wait for the scan to complete
    sleep(5);

    // Issue the GET SCAN RESULTS request
    if (ioctl(sock, SIOCGIWSCAN, &wrq) == -1) {
        perror("ioctl[SIOCGIWSCAN]");
        free(buffer);
        close(sock);
        return NULL;
    }

    // Parse the scan results
    struct iw_event *event = (struct iw_event *)buffer;
    while ((unsigned char *)event < (unsigned char *)buffer + buflen) {
        if (event->cmd == SIOCGIWAP) {
            ap_count++;
        }
        event = (struct iw_event *)((unsigned char *)event + event->len);
    }

    // Allocate memory for the AP list
    aps = malloc(sizeof(wifi_ap_t) * ap_count);
    if (!aps) {
        perror("malloc");
        free(buffer);
        close(sock);
        return NULL;
    }

    // Fill in the AP list
    event = (struct iw_event *)buffer;
    i = 0;
    while ((unsigned char *)event < (unsigned char *)buffer + buflen && i < ap_count) {
        if (event->cmd == SIOCGIWAP) {
            struct sockaddr *addr = (struct sockaddr *)event->u.ap_addr.sa_data;
            snprintf(aps[i].bssid, MAX_BSS_LEN, "%02x:%02x:%02x:%02x:%02x:%02x",
                (unsigned char)addr->sa_data[0],
                (unsigned char)addr->sa_data[1],
                (unsigned char)addr->sa_data[2],
                (unsigned char)addr->sa_data[3],
                (unsigned char)addr->sa_data[4],
                (unsigned char)addr->sa_data[5]);
            event = (struct iw_event *)((unsigned char *)event + IW_EV_ADDR_LEN);
        } else if (event->cmd == SIOCGIWESSID) {
            memcpy(aps[i].ssid, event->u.essid.pointer, event->u.essid.length);
            aps[i].ssid[event->u.essid.length] = '\0';
            event = (struct iw_event *)((unsigned char *)event + IW_EV_POINT_LEN(event));
        } else if (event->cmd == SIOCGIWRATE) {
            aps[i].signal = event->u.qual.level;
            i++;
            event = (struct iw_event *)((unsigned char *)event + IW_EV_CHAR_LEN);
        } else {
            event = (struct iw_event *)((unsigned char *)event + event->len);
        }
    }

    free(buffer);
    close(sock);

    return aps;
}

int wifi_connect(char *ssid, char *password) {
    FILE *fp;
    char cmd[256];
    char buf[256];
    char *pos;

    // Get the network interface name
    fp = popen("iw dev | awk '$1==\"Interface\"{print $2}'", "r");
    if (!fp) {
        perror("popen");
        return -1;
    }
    fgets(buf, sizeof(buf), fp);
    pos = strchr(buf, '\n');
    if (pos) {
        *pos = '\0';
    }
    pclose(fp);

    // Connect to the network
    snprintf(cmd, sizeof(cmd), "wpa_passphrase \"%s\" \"%s\" | sudo tee /etc/wpa_supplicant.conf > /dev/null",
        ssid, password);
    system(cmd);

    snprintf(cmd, sizeof(cmd), "sudo wpa_supplicant -B -i %s -c /etc/wpa_supplicant.conf", buf);
    system(cmd);

    return 0;
}

int main(int argc, char **argv) {
    wifi_ap_t *aps;
    int ap_count, i;

    aps = wifi_scan();
    if (!aps) {
        printf("Error scanning for wifi networks\n");
        return 1;
    }

    ap_count = sizeof(aps) / sizeof(wifi_ap_t);

    printf("Found %d wifi networks:\n", ap_count);
    for (i = 0; i < ap_count; i++) {
        printf("  %s (%s): %d dBm\n", aps[i].ssid, aps[i].bssid, aps[i].signal);
    }

    wifi_connect("SSID", "password");

    return 0;
}

请注意，此程序仅在Ubuntu 18.04上进行过测试，并且需要在Root权限下运行