mtk android10 蓝牙默认mac地址修改

mtk android10 蓝牙默认mac地址修改

mac地址可以通过官方工具手动写入，一个个写太麻烦了，要求也没有那么高，改为使用emmc id生成蓝牙mac地址。开机如果读到的蓝牙mac地址无效，会随机生成一个，然后进行保存，通过查找代码定位到文件

vendor/mediatek/proprietary/hardware/connectivity/bluetooth/driver/mt66xx/bluedroid/radiomod.c

中的GetRandomValue函数，修改这个函数就可以了，详细代码如下

int sthvalue(char c)
{
	int value;
	if((c>='0')&&(c<='9'))
		value=48;
	else if((c>='a')&&(c<='f'))
		value=87;
	else if((c>='A')&&(c<='F'))
		value=55;
	else{
		return -1;
	}
	return value;
}

int strtohex(char *str,char *data)
{
	int len=0;
	int sum=0;
	int high=0;
	int low=0;
	int value=0;
	int j=0;
	int i;
	len=strlen(str);
	//printf("%d\n",len);
	for(i=0;i<len;i++)
	{
		value=sthvalue(str[i]);
		high=(((str[i]-value)&0xF)<<4);
		value=sthvalue(str[i+1]);
		low=((str[i+1]-value)&0xF);
		sum=high|low;
		j=i/2;
		data[j]=sum;
		i=i+1;
	}
	return len;
}

#define CID_PATH "/sys/block/mmcblk0/device/cid"
#define CID_BUFFER_SIZE 33
/**
 * 读取eMMC CID信息
 * @param cid_buf: 输出缓冲区
 * @param buf_size: 缓冲区大小
 * @return: 成功返回0，失败返回-1
 */
int read_mmc_cid(char *cid_buf, size_t buf_size) {
    FILE *fp = NULL;
    char *line = NULL;
    size_t len = 0;
    ssize_t read;
    int ret = -1;

    if (cid_buf == NULL || buf_size < CID_BUFFER_SIZE) {
        return -1;
    }

    // 打开CID文件
    fp = fopen(CID_PATH, "r");
    if (fp == NULL) {
        return -1;
    }

    // 读取一行内容
    read = getline(&line, &len, fp);
    if (read != -1) {
        // 移除可能的换行符
        if (read > 0 && line[read-1] == '\n') {
            line[read-1] = '\0';
        }
        
        // 确保不超过缓冲区大小
        strncpy(cid_buf, line, buf_size - 1);
        cid_buf[buf_size - 1] = '\0';
        ret = 0;
    }

    // 清理资源
    if (line) {
        free(line);
    }
    fclose(fp);
    
    return ret;
}

int get_emmcid_for_generate_mac(UCHAR* btmac)
{
	INT32 ret = 0;
	UCHAR emmcid[CID_BUFFER_SIZE];
	ret = read_mmc_cid(emmcid,CID_BUFFER_SIZE);
	if(ret < 0){
		LOG_WAN("read emmc id failed\n");
		return ret;
	}
	LOG_WAN("read emmc id: %s\n",emmcid);
	strtohex(emmcid,btmac);
	return ret;
}
//add end
UCHAR GetRandomByte(UCHAR exclude)
{
    struct timeval tv;
    UCHAR ret = exclude;
    while(ret == exclude) {
        gettimeofday(&tv, NULL);
        srand(tv.tv_usec);
        ret = ((rand()>>8) & 0xFF);
    }
    return ret;
}

static VOID GetRandomValue(UCHAR string[6])
{
    INT32 iRandom = 0;
	INT32 ret = 0;
	UCHAR emmccid[32];
	ret = get_emmcid_for_generate_mac(emmccid);
	if(ret == 0){
	    LOG_WAN("Use emmc id gen bt mac\n");
        string[0] = ((emmccid[0] ^ emmccid[1] ^ emmccid[2] ^ emmccid[3]) & 0xFE) | (0x02);
		string[1] = (emmccid[8] ^ emmccid[9] ^ emmccid[10] ^ emmccid[11]);//(emmccid[4] ^ emmccid[5] ^ emmccid[6] ^ emmccid[7]);
    	string[3] = ((emmccid[13] ^ emmccid[12] ^ emmccid[5] ^ emmccid[6]) & (0xef));//must not be 0x9e
    	string[4] = emmccid[14];
        string[5] = emmccid[15] + 1;
	} else {
	    LOG_WAN("Enable random generation\n");
		/* Initialize random seed */
		srand(time(NULL));
		iRandom = rand();
		string[0] = (((iRandom>>24|iRandom>>16) & (0xFE)) | (0x02)); /* Must use private bit(1) and no BCMC bit(0) */
		string[1] = GetRandomByte(0x00);
		/* Generate random LAP, exclude 0x9E8B00 ~ 0x9E8BFF*/
		string[3] = GetRandomByte(0x9E);
		string[4] = GetRandomByte(0x8B);
		string[5] = GetRandomByte(0x00);
	}
	LOG_WAN("Generate bd_addr:  %02x-%02x-%02x-%02x-%02x-%02x\n",
	    string[0], string[1], string[2], string[3], string[4], string[5]);
    return;
}

其中mac地址的生成方式可以自定义

        string[0] = ((emmccid[0] ^ emmccid[1] ^ emmccid[2] ^ emmccid[3]) & 0xFE) | (0x02);
		string[1] = (emmccid[8] ^ emmccid[9] ^ emmccid[10] ^ emmccid[11]);//(emmccid[4] ^ emmccid[5] ^ emmccid[6] ^ emmccid[7]);
    	string[3] = ((emmccid[13] ^ emmccid[12] ^ emmccid[5] ^ emmccid[6]) & (0xef));//must not be 0x9e
    	string[4] = emmccid[14];
        string[5] = emmccid[15] + 1;

目前测试使用正常。 需要增加头文件

#include <string.h>
#include <unistd.h>
#include <errno.h>

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作者：hclydao

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