帮我解读注释这段代码static int wan_config_set(struct ubus_context *ctx, struct ubus_object *obj, struct ubus_request_data *req, const char *method, struct blob_attr *msg) { INT32 iRet = RET_PM_OK; //INT32 DefaultFlag = 0; T_CTCAPD_WANINFO_SET ctcapd_waninfo_set; iRet = __wan_config_set(msg, 1, &ctcapd_waninfo_set); if(iRet != UBUS_STATUS_OK) return iRet; iRet = pm_ubus_waninfo_set(&ctcapd_waninfo_set); if (iRet != RET_PM_OK) { OssUserLogError("pm_ubus_waninfo_set failed: %d", iRet); return UBUS_STATUS_UNKNOWN_ERROR; } return UBUS_STATUS_OK; }

这段代码是一个函数`wan_config_set`，用于处理UBus请求并设置WAN配置。下面是对代码注释的解读：

static int wan_config_set(struct ubus_context *ctx, struct ubus_object *obj,
                          struct ubus_request_data *req, const char *method,
                          struct blob_attr *msg)
{
    INT32 iRet = RET_PM_OK;
    //INT32 DefaultFlag = 0;
    T_CTCAPD_WANINFO_SET ctcapd_waninfo_set;
    
    // 调用__wan_config_set函数，传入消息和waninfo_set结构体的指针
    // __wan_config_set函数将解析消息，将相关的配置信息存储在waninfo_set结构体中
    iRet = __wan_config_set(msg, 1, &ctcapd_waninfo_set);
    if(iRet != UBUS_STATUS_OK)
        return iRet;
    
    // 调用pm_ubus_waninfo_set函数，将waninfo_set结构体中的配置信息应用到系统中
    iRet = pm_ubus_waninfo_set(&ctcapd_waninfo_set);
    if (iRet != RET_PM_OK)
    {
        // 如果应用配置失败，输出错误日志并返回UBUS_STATUS_UNKNOWN_ERROR
        OssUserLogError("pm_ubus_waninfo_set failed: %d", iRet);
        return UBUS_STATUS_UNKNOWN_ERROR;
    }
    
    // 返回UBUS_STATUS_OK表示成功处理请求
    return UBUS_STATUS_OK;
}

该函数接受UBus相关参数，从消息中解析WAN配置信息，并将其应用到系统中。如果应用配置失败，将输出错误日志并返回`UBUS_STATUS_UNKNOWN_ERROR`。否则，返回`UBUS_STATUS_OK`表示成功处理请求。