The Mirai attacks of 2016 have shown the devastating DDoS potential of compromised IoT devices (primarily IoT cameras and DVRs), when nearly half a million of these devices were used to launch some of the largest and most devastating DDoS attacks recorded to date. One would hope that a full year later, the users and administrators of Internet-facing IoT devices have taken at least the basic measures towards reducing the likelihood that their devices get recruited as facilitators/executors of direct or reflected DDoS attacks. Unfortunately, the results of our recent study involving real-world IoT cameras and DVRs are rather discouraging as they show that: 1) with the existence of publicly accessible IoT search engines, such as Shodan, it has become easier than ever for hacker to discover and compromise IoT devices, of any kind and anywhere in the world, and 2) a significant number of these devices are inadequately protected against TCP-SYN floods and DDoS reflection - either by means of firewalls or at the OS-level. The aim of this article is to serve as a wake-up call to the users and administrators of Internet-facing IoT devices, and alert to the need to better protect these devices form being coopted by hackers for purposes of DDoS attacks.
{"title":"IoT Cameras and DVRs as DDoS Reflectors: Pros and Cons from Hacker’s Perspective","authors":"N. Vlajic, Daiwei Zhou, Jonathan Tung","doi":"10.1109/ICII.2018.00035","DOIUrl":"https://doi.org/10.1109/ICII.2018.00035","url":null,"abstract":"The Mirai attacks of 2016 have shown the devastating DDoS potential of compromised IoT devices (primarily IoT cameras and DVRs), when nearly half a million of these devices were used to launch some of the largest and most devastating DDoS attacks recorded to date. One would hope that a full year later, the users and administrators of Internet-facing IoT devices have taken at least the basic measures towards reducing the likelihood that their devices get recruited as facilitators/executors of direct or reflected DDoS attacks. Unfortunately, the results of our recent study involving real-world IoT cameras and DVRs are rather discouraging as they show that: 1) with the existence of publicly accessible IoT search engines, such as Shodan, it has become easier than ever for hacker to discover and compromise IoT devices, of any kind and anywhere in the world, and 2) a significant number of these devices are inadequately protected against TCP-SYN floods and DDoS reflection - either by means of firewalls or at the OS-level. The aim of this article is to serve as a wake-up call to the users and administrators of Internet-facing IoT devices, and alert to the need to better protect these devices form being coopted by hackers for purposes of DDoS attacks.","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127066285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Traditional wireless video transmission scheme faces a cliff-edge effect, a rapid decline in signal quality, when dealing with mobile and broadcast scenarios, which is unaccepted in industrial network. SoftCast is a novel solution which can overcome the cliff-edge effect. In order to solve the traditional wireless video transmission scheme's weakness and meet the terminals' demands. We use a DSP with independent property rights and dedicated hardware accelerators to implement a reconfigurable SoC for SoftCast video transmission solution named Reconfigurable SoftCast SoC (RSS).
{"title":"A Reconfigurable SoC for SoftCast Wireless Video Transmission","authors":"Fengxiang Gao, Haoqi Gao, Jun Wu","doi":"10.1109/ICII.2018.00029","DOIUrl":"https://doi.org/10.1109/ICII.2018.00029","url":null,"abstract":"Traditional wireless video transmission scheme faces a cliff-edge effect, a rapid decline in signal quality, when dealing with mobile and broadcast scenarios, which is unaccepted in industrial network. SoftCast is a novel solution which can overcome the cliff-edge effect. In order to solve the traditional wireless video transmission scheme's weakness and meet the terminals' demands. We use a DSP with independent property rights and dedicated hardware accelerators to implement a reconfigurable SoC for SoftCast video transmission solution named Reconfigurable SoftCast SoC (RSS).","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127274310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"[Copyright notice]","authors":"","doi":"10.1109/icii.2018.00003","DOIUrl":"https://doi.org/10.1109/icii.2018.00003","url":null,"abstract":"","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"63 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131963580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cellular networks with D2D links are increasingly being explored for mission-critical applications, and it is critical to control interference among concurrent transmissions in a predictable manner to ensure the required communication reliability. To this end, we propose a Unified Cellular Scheduling (UCS) framework that, based on the Physical-Ratio-K (PRK) interference model, schedules uplink, downlink, and D2D transmissions in a unified manner to ensure predictable communication reliability while maximizing channel spatial reuse. UCS also provides a simple, effective approach to mode selection that maximizes the communication capacity for each involved communication pair. UCS effectively uses multiple channels for high throughput as well as resilience to channel fading and external interference. Leveraging the availability of base stations (BSes) as well as highspeed, out-of-band connectivity between BSes, UCS effectively orchestrates the functionalities of BSes and user equipment (UE) for light-weight control signaling and ease of incremental deployment and integration with existing cellular standards. We have implemented UCS using the open-source, standardscompliant cellular networking platform OpenAirInterface. We have validated the OpenAirInterface implementation using USRP B210 software-defined radios and lab deployment. We have also evaluated UCS through high-fidelity, at-scale simulation studies. Our experiments show that UCS ensures predictable communication reliability while achieving a higher channel spatial reuse rate than existing mechanisms. Additionally, the distributed UCS framework enables a channel spatial reuse rate statistically equal to that in the state-of-the-art centralized scheduling algorithm iOrder.
具有D2D链路的蜂窝网络正越来越多地用于关键任务应用，以可预测的方式控制并发传输之间的干扰以确保所需的通信可靠性至关重要。为此，我们提出了一个统一蜂窝调度(UCS)框架，该框架基于物理比- k (PRK)干扰模型，以统一的方式调度上行链路、下行链路和D2D传输，以确保可预测的通信可靠性，同时最大化信道空间重用。UCS还提供了一种简单、有效的模式选择方法，使每个相关通信对的通信容量最大化。UCS有效地利用了多信道的高吞吐量以及对信道衰落和外部干扰的弹性。利用基站(BSes)的可用性以及基站之间的高速带外连接，UCS有效地协调了基站和用户设备(UE)的功能，以实现轻量级控制信令，并易于增量部署和与现有蜂窝标准的集成。我们使用开源、符合标准的蜂窝网络平台OpenAirInterface实现了UCS。我们使用USRP B210软件定义无线电和实验室部署验证了OpenAirInterface的实现。我们还通过高保真度、大规模模拟研究评估了UCS。我们的实验表明，UCS保证了可预测的通信可靠性，同时实现了比现有机制更高的信道空间复用率。此外，分布式UCS框架使信道空间重用率在统计上等同于最先进的集中式调度算法iOrder。
{"title":"Unified Scheduling for Predictable Communication Reliability in Industrial Cellular Networks","authors":"Yuwei Xie, Hongwei Zhang, Pengfei Ren","doi":"10.1109/ICII.2018.00022","DOIUrl":"https://doi.org/10.1109/ICII.2018.00022","url":null,"abstract":"Cellular networks with D2D links are increasingly being explored for mission-critical applications, and it is critical to control interference among concurrent transmissions in a predictable manner to ensure the required communication reliability. To this end, we propose a Unified Cellular Scheduling (UCS) framework that, based on the Physical-Ratio-K (PRK) interference model, schedules uplink, downlink, and D2D transmissions in a unified manner to ensure predictable communication reliability while maximizing channel spatial reuse. UCS also provides a simple, effective approach to mode selection that maximizes the communication capacity for each involved communication pair. UCS effectively uses multiple channels for high throughput as well as resilience to channel fading and external interference. Leveraging the availability of base stations (BSes) as well as highspeed, out-of-band connectivity between BSes, UCS effectively orchestrates the functionalities of BSes and user equipment (UE) for light-weight control signaling and ease of incremental deployment and integration with existing cellular standards. We have implemented UCS using the open-source, standardscompliant cellular networking platform OpenAirInterface. We have validated the OpenAirInterface implementation using USRP B210 software-defined radios and lab deployment. We have also evaluated UCS through high-fidelity, at-scale simulation studies. Our experiments show that UCS ensures predictable communication reliability while achieving a higher channel spatial reuse rate than existing mechanisms. Additionally, the distributed UCS framework enables a channel spatial reuse rate statistically equal to that in the state-of-the-art centralized scheduling algorithm iOrder.","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114407755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is about reconciling the highly asynchronous untimed interactions that prevail on the Internet with time-sensitive operations of Things in the Internet of Things (IoT). Specifically, this paper addresses a design pattern that is widely used on the Internet called asynchronous atomic callbacks (AAC). We show that it is possible and practical to endow AACs with temporal semantics that can make system behaviors more repeatable and testable and can make the interactions between cyber services and physical Things safer. Our approach brings some of the key advantages of synchronous languages, specifically deterministic concurrency and logical synchrony. We show how a well-defined notion of logical time is compatible with AAC and can be used to endow applications with semantic notions of simultaneity, give them more control over the ordering of events, and enable the specification of real-time behaviors that nevertheless recognize the often long and highly variable latencies introduced in the Internet. We introduce labeled logical clock domains (LLCDs), which permit arbitrary mixtures of synchronized and unsynchronized behaviors and we show how LLCDs can be realized in the JavaScript language, which is widely used in Internet applications.
{"title":"Deterministic Timing for the Industrial Internet of Things","authors":"Chadlia Jerad, Edward A. Lee","doi":"10.1109/ICII.2018.00010","DOIUrl":"https://doi.org/10.1109/ICII.2018.00010","url":null,"abstract":"This paper is about reconciling the highly asynchronous untimed interactions that prevail on the Internet with time-sensitive operations of Things in the Internet of Things (IoT). Specifically, this paper addresses a design pattern that is widely used on the Internet called asynchronous atomic callbacks (AAC). We show that it is possible and practical to endow AACs with temporal semantics that can make system behaviors more repeatable and testable and can make the interactions between cyber services and physical Things safer. Our approach brings some of the key advantages of synchronous languages, specifically deterministic concurrency and logical synchrony. We show how a well-defined notion of logical time is compatible with AAC and can be used to endow applications with semantic notions of simultaneity, give them more control over the ordering of events, and enable the specification of real-time behaviors that nevertheless recognize the often long and highly variable latencies introduced in the Internet. We introduce labeled logical clock domains (LLCDs), which permit arbitrary mixtures of synchronized and unsynchronized behaviors and we show how LLCDs can be realized in the JavaScript language, which is widely used in Internet applications.","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"554 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134155411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"ICII 2018 Reviewers","authors":"","doi":"10.1109/icii.2018.00008","DOIUrl":"https://doi.org/10.1109/icii.2018.00008","url":null,"abstract":"","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114599222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Process automation is embracing wireless sensor-actuator networks (WSANs) in the era of Industrial Internet. Despite the success of WSANs for monitoring applications, feedback control poses significant challenges due to data loss and stringent energy constraints in WSANs. Holistic control adopts a cyber-physical system approach to overcome the challenges by orchestrating network reconfiguration and process control at run time. In this paper, we explore efficient holistic control designs to maintain control performance while reducing the communication cost. The contributions of this work are four-fold: (1) We introduce a holistic control architecture that integrates low-power wireless bus (LWB) and two control strategies, rate adaptation and self-triggered control, specifically proposed to reduce communication cost; (2) We design novel wireless network mechanisms to support rate adaptation and self-triggered control, respectively, in a multi-hop WSAN; (3) We build a real-time network-in-the-loop simulator that integrates MATLAB/Simulink and a three-floor WSAN testbed to evaluate wireless control systems; (4) We empirically explore the tradeoff between communication cost and control performance under alternative holistic control approaches. Our case studies show that rate adaptation and self-triggered control offer advantages in control performance and energy efficiency, respectively, in normal operating conditions. The advantage in energy efficiency of self-triggered control, however, may diminish under harsh physical and wireless conditions due to the cost of recovering from data loss and physical disturbances.
{"title":"Efficient Holistic Control over Industrial Wireless Sensor-Actuator Networks","authors":"Yehan Ma, Chenyang Lu","doi":"10.1109/ICII.2018.00018","DOIUrl":"https://doi.org/10.1109/ICII.2018.00018","url":null,"abstract":"Process automation is embracing wireless sensor-actuator networks (WSANs) in the era of Industrial Internet. Despite the success of WSANs for monitoring applications, feedback control poses significant challenges due to data loss and stringent energy constraints in WSANs. Holistic control adopts a cyber-physical system approach to overcome the challenges by orchestrating network reconfiguration and process control at run time. In this paper, we explore efficient holistic control designs to maintain control performance while reducing the communication cost. The contributions of this work are four-fold: (1) We introduce a holistic control architecture that integrates low-power wireless bus (LWB) and two control strategies, rate adaptation and self-triggered control, specifically proposed to reduce communication cost; (2) We design novel wireless network mechanisms to support rate adaptation and self-triggered control, respectively, in a multi-hop WSAN; (3) We build a real-time network-in-the-loop simulator that integrates MATLAB/Simulink and a three-floor WSAN testbed to evaluate wireless control systems; (4) We empirically explore the tradeoff between communication cost and control performance under alternative holistic control approaches. Our case studies show that rate adaptation and self-triggered control offer advantages in control performance and energy efficiency, respectively, in normal operating conditions. The advantage in energy efficiency of self-triggered control, however, may diminish under harsh physical and wireless conditions due to the cost of recovering from data loss and physical disturbances.","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115551078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Today's commercially available drones commonly make use of the 2.4 GHz channel for remote communication. A drawback is the short communication range. To remedy the drawback, we explore the use of 4G network as an alternative. A drone-based experiment platform is developed to evaluate 4G network for air-ground data transmission. Our field experiment shows that 4G network is capable of supporting low-altitude air-ground communication with good connectivity and low packet loss although the packet loss would increase substantially when the signal strength decreases.
{"title":"4G Network for Air-Ground Data Transmission: A Drone Based Experiment","authors":"Liqi Chen, Zheng Huang, Zhenbang Liu, Dawei Liu, Xin Huang","doi":"10.1109/ICII.2018.00028","DOIUrl":"https://doi.org/10.1109/ICII.2018.00028","url":null,"abstract":"Today's commercially available drones commonly make use of the 2.4 GHz channel for remote communication. A drawback is the short communication range. To remedy the drawback, we explore the use of 4G network as an alternative. A drone-based experiment platform is developed to evaluate 4G network for air-ground data transmission. Our field experiment shows that 4G network is capable of supporting low-altitude air-ground communication with good connectivity and low packet loss although the packet loss would increase substantially when the signal strength decreases.","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122462193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. P. Modekurthy, Dali Ismail, Mahbubur Rahman, Abusayeed Saifullah
Recent advancements in industrial Internet-of-Things (IoT), more specifically, the development of industrial wireless standards such as WirelessHART and ISA100, are paving the way for the fourth industrial revolution, Industry 4.0. These wireless standards specify highly reliable and real-time communications as key requirements in industrial wireless sensor-actuator networks. Schedulability analysis remains the cornerstone for analyzing the real-time performance of these networks. While it is well-explored in the domain of CPU scheduling, schedulability analysis for multi-hop wireless networks has seen little progress till date. Existing work mostly focuses on worst-case delay analysis that runs in pseudo-polynomial time, making it is less suitable under frequent network dynamics which are quite common in industrial IoT. To address this, in this paper, we develop a schedulability analysis based on utilization bound for multi-hop, multi-channel industrial wireless sensor-actuator networks. Because of its extremely low runtime overhead, utilization-based schedulability test is considered to be one of the highly efficient and effective schedulability analyses. However, no work has been done yet on utilization-based analysis for multi-hop wireless network. The key challenge for a utilization-based test for multi-hop wireless network arises from the fact that wireless network is subject to transmission conflict and network dynamics which are not present in CPU scheduling. We address this challenge by bridging the gap between wireless domain and CPU task scheduling. We have evaluated our result through simulations using TOSSIM that shows that our schedulability analysis is safe and effective in practice.
{"title":"A Utilization-Based Approach for Schedulability Analysis in Wireless Control Systems","authors":"V. P. Modekurthy, Dali Ismail, Mahbubur Rahman, Abusayeed Saifullah","doi":"10.1109/ICII.2018.00014","DOIUrl":"https://doi.org/10.1109/ICII.2018.00014","url":null,"abstract":"Recent advancements in industrial Internet-of-Things (IoT), more specifically, the development of industrial wireless standards such as WirelessHART and ISA100, are paving the way for the fourth industrial revolution, Industry 4.0. These wireless standards specify highly reliable and real-time communications as key requirements in industrial wireless sensor-actuator networks. Schedulability analysis remains the cornerstone for analyzing the real-time performance of these networks. While it is well-explored in the domain of CPU scheduling, schedulability analysis for multi-hop wireless networks has seen little progress till date. Existing work mostly focuses on worst-case delay analysis that runs in pseudo-polynomial time, making it is less suitable under frequent network dynamics which are quite common in industrial IoT. To address this, in this paper, we develop a schedulability analysis based on utilization bound for multi-hop, multi-channel industrial wireless sensor-actuator networks. Because of its extremely low runtime overhead, utilization-based schedulability test is considered to be one of the highly efficient and effective schedulability analyses. However, no work has been done yet on utilization-based analysis for multi-hop wireless network. The key challenge for a utilization-based test for multi-hop wireless network arises from the fact that wireless network is subject to transmission conflict and network dynamics which are not present in CPU scheduling. We address this challenge by bridging the gap between wireless domain and CPU task scheduling. We have evaluated our result through simulations using TOSSIM that shows that our schedulability analysis is safe and effective in practice.","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125694964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"[Publisher's information]","authors":"","doi":"10.1109/icii.2018.00040","DOIUrl":"https://doi.org/10.1109/icii.2018.00040","url":null,"abstract":"","PeriodicalId":330919,"journal":{"name":"2018 IEEE International Conference on Industrial Internet (ICII)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134179823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：