daemon.c

嵌入式无线网络实验中

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
#include <time.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/time.h>

#include "daemon.h"
#include <drvpriv.h>
#include "wireless_copy.h"

unsigned char essid[32];
unsigned char old_essid[32];

extern int print_scanning_info(FILE *pFile, int skfd, char *ifname);

static void init_daemon(void)
{
	int pid;
	int i;
	
	if(pid=fork())
	exit(0);
	else if(pid<0)
	exit(1);

	setsid();
	if(pid=fork())
	exit(0);
	else if(pid<0)
	exit(1);

	chdir("/tmp/yaffs");
	umask(0);

	return;
}

static int mystrcmp(char *s, char *t)
{
	while(*s!='\0' && *t!='\0' && *s==*t)
	{
		++s;
		++t;
	}
	if(*s=='\0' || *t=='\0')
		return 0;
	else
		return -1;
}

static int daemon_drv_get_scan_results(FILE *pFile, struct wpa_scan_result *results, size_t max_size)
{
	struct iwreq pstWrq;
	int  ret = 0;
	int i,ioctl_sock,level,curr_i,first_come;
	char cmd[255];

        struct iwdrv_priv_oid iw_p;

	ioctl_sock = socket(PF_INET,SOCK_DGRAM,0);

	//更新level
	//system("/tmp/yaffs/iwlist2 eth1 scan");
	print_scanning_info(pFile, ioctl_sock, "eth1");
	
	ioctl(ioctl_sock, SIOCSIWSCAN, &pstWrq);
	
	memset(cmd, 0, sizeof(cmd));
	memset(results, 0, max_size * sizeof(struct wpa_scan_result));
	
        iw_p.priv_id = HEOCGIWDPSCRES;
        iw_p.length = max_size * sizeof(struct wpa_scan_result);
        iw_p.pointer = (caddr_t)results;

	memset(&pstWrq, 0, sizeof(pstWrq));
	strncpy(pstWrq.ifr_name, "eth1", IFNAMSIZ);

        pstWrq.u.data.pointer = (caddr_t)&iw_p;
	pstWrq.u.data.length = max_size * sizeof(struct wpa_scan_result) + sizeof(struct iwdrv_priv_oid);
	
	if (ioctl(ioctl_sock, HEOCDRIVPRIV, &pstWrq) < 0) {
		//perror("ioctl error HEOCDRIVPRIV!");
		ret = -1;
	}
	
	ret = iw_p.flags;
	fprintf(pFile, "ret = %d\n", ret);

	//根据scan结果确定连接对象
	first_come = 0;
	curr_i = -1;
	for(i=0;i<ret;i++)
	{
		if(mystrcmp((char *)((struct wpa_scan_result *)(results + i)->ssid),"njdt-")!=0 && mystrcmp((char *)((struct wpa_scan_result *)(results + i)->ssid),"NJDT-")!=0)
			continue;
		//fprintf(pFile, "%d >> bssid = %s\n", i+1, (struct wpa_scan_result *)(results + i)->bssid);
		fprintf(pFile, "%d >> ssid = %s\n", i+1, (struct wpa_scan_result *)(results + i)->ssid);
		//fprintf(pFile, "%d >> wpa_ie = %s\n", i+1, (struct wpa_scan_result *)(results + i)->wpa_ie);
		//fprintf(pFile, "%d >> rsn_ie = %s\n", i+1, (struct wpa_scan_result *)(results + i)->rsn_ie);
		//fprintf(pFile, "%d >> freq = %d\n", i+1, (struct wpa_scan_result *)(results + i)->freq);
		//fprintf(pFile, "%d >> caps = %d\n", i+1, (struct wpa_scan_result *)(results + i)->caps);
		//fprintf(pFile, "%d >> qual = %d\n", i+1, (struct wpa_scan_result *)(results + i)->qual);
		//fprintf(pFile, "%d >> noise = %d\n", i+1, (struct wpa_scan_result *)(results + i)->noise);
		fprintf(pFile, "%d >> level = %d\n", i+1, (struct wpa_scan_result *)(results + i)->level);
		if((int)((struct wpa_scan_result *)(results + i)->level) > level || first_come == 0)
		{
			first_come = 1;
			level = (int)(struct wpa_scan_result *)(results + i)->level;
			curr_i = i;
		}
	}

	if(curr_i == -1)//未检测到njdt的sta
		return ret;

	memcpy(essid, (struct wpa_scan_result *)(results + curr_i)->ssid, 32);
	fprintf(pFile, "%d >> selected ssid = %s\n", i+1, essid);

	//get old essid
	memset(&pstWrq, 0, sizeof(pstWrq));
	strncpy(pstWrq.ifr_name, "eth1", IFNAMSIZ);
	pstWrq.u.essid.pointer = (caddr_t)old_essid;
	pstWrq.u.essid.length = 32;
	pstWrq.u.essid.flags = 0;
	ioctl(ioctl_sock, SIOCGIWESSID, &pstWrq);
	fprintf(pFile, "haha ** old_essid = %s\n", old_essid);
	if(strcmp(essid, old_essid)!=0)
	{
		//struct timeval tv;
		//struct timezone tz;
		//strcpy(cmd, "iwconfig eth1 essid ");
		//strcat(cmd, essid);
		//gettimeofday(&tv, &tz);
		//fprintf(pFile, "before ** tv_sec = %d\n", tv.tv_sec);
		//fprintf(pFile, "before ** tv_usec = %d\n", tv.tv_usec);
		//system(cmd);
		//gettimeofday(&tv, &tz);
		//连接sta
		//set new essid
		memset(&pstWrq, 0, sizeof(pstWrq));
		strncpy(pstWrq.ifr_name, "eth1", IFNAMSIZ);
		pstWrq.u.essid.pointer = (caddr_t)essid;
		pstWrq.u.essid.length = strlen(essid)+1;
		pstWrq.u.essid.flags = 1;
		ioctl(ioctl_sock, SIOCSIWESSID, &pstWrq);
		//fprintf(pFile, "after ** tv_sec = %d\n", tv.tv_sec);
		//fprintf(pFile, "after ** tv_usec = %d\n", tv.tv_usec);
	}

	close(ioctl_sock);

	return ret;

}

static int daemon_get_scan_results()
{
#define SCAN_AP_LIMIT 16
	struct wpa_scan_result *results, *tmp;
	int num;

        FILE *pFile;

	pFile = fopen("/tmp/yaffs/log.txt","at");

	results = malloc(SCAN_AP_LIMIT * sizeof(struct wpa_scan_result));
	if (results == NULL) {
		fprintf(pFile, "Failed to allocate memory for scan results");
		return -1;
	}

	num = daemon_drv_get_scan_results(pFile, results, SCAN_AP_LIMIT);
	fprintf(pFile, "Scan results num: %d\n", num);
	if (num < 0) {
		fprintf(pFile, "Failed to get scan results");
		free(results);
		return -1;
	}
	if (num > SCAN_AP_LIMIT) {
		fprintf(pFile, "Not enough room for all APs (%d < %d)", num, SCAN_AP_LIMIT);
		num = SCAN_AP_LIMIT;
	}

	fclose(pFile);

	return 0;
}

static int eth1_detect()
{
	char buff[256];
	FILE *fh;
	fh = fopen("/proc/net/wireless","r");
	if(fh != NULL)
	{
		fgets(buff, sizeof(buff), fh);
		fgets(buff, sizeof(buff), fh);
		while(fgets(buff, sizeof(buff), fh))
		{
			if(strstr(buff, "eth1") != 0)
			{
				fclose(fh);
				return 1;
			}
		}
		fclose(fh);
	}
	return 0;
}

main()
{
	init_daemon();
	while(eth1_detect() == 0)
	{
		sleep(50);
	}
	system("iwconfig eth1 mode ad-hoc");
	while(1)
	{
		//开始处理sta切换
		daemon_get_scan_results();
		sleep(10);
		//usleep(1000000);
	}
}