Vehicle communication apparatus and in-vehicle network system

Abstract

To enhance the security while suppressing increase in development cost and reduction in communication performance due to Ethernet (R) on an in-vehicle network.SOLUTION: A plurality of ECUs 2 communicate frame information having a VLAN tag and an IP header according to an Ethernet protocol via an in-vehicle network 3. Each of the ECUs 2 includes: a priority determination unit 22A which determines the priority of receiving frame information, using priority information of one of PCP in the VLAN tag and ToS in the IP header in the receiving frame information; a transmission information rewriting unit 21A which rewrites an other priority information not used for the priority determination in transmission frame information, in accordance with a predetermined algorithm; and a receiving information authentication unit 22B which authenticates the receiving frame information when the other priority information in the receiving frame information has been rewritten according to the algorithm.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vehicle communication device and an in-vehicle network system. [Background technology]

[0002] Recently, the application of Ethernet communication to vehicles is progressing, with the establishment of standards for in-vehicle Ethernet (registered trademark) as a next-generation high-speed communication technology in vehicles such as automobiles. For example, Patent Document 1 discloses a communication device in which an ECU connected to an in-vehicle network performs encryption by excluding a field in the payload of an Ethernet frame in which a value for priority control is stored. In this communication device, an Ethernet frame is obtained in which only the header and priority are in plain text and other data in the payload is encrypted, eliminating the need to decrypt and re-encrypt the frame for each bridge, thereby achieving both security and performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-60083 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when preventing unauthorized communication by encrypting a part of the Ethernet frame communicated on the in-vehicle network as in the above conventional technology, the amount of data that can be transmitted in one frame decreases compared to the case where encryption is not performed due to the increase in data size caused by encryption. In addition, in order to support encryption and decryption, it is necessary to manage a common key, perform encryption calculations, replace the PHY transceiver, etc., which increases development costs. Furthermore, there is also the issue that the addition of encryption and decryption processes causes a decrease in communication speed and processing delays.

[0005] The present invention has been made in light of the above points, and aims to provide a vehicle communication device and an in-vehicle network system that can enhance security while suppressing performance degradation and increased development costs of Ethernet communications on an in-vehicle network. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present invention provides a vehicle communication device that transmits and receives frame information having a VLAN tag and an IP header according to an Ethernet protocol on an in-vehicle network mounted on a vehicle, the vehicle communication device including: a priority determination unit that determines a priority of received frame information using one of priority information of a PCP field in the VLAN tag and priority information of a ToS field in the IP header in received frame information received from the in-vehicle network, a transmission information rewriting unit that rewrites the other priority information of the priority information of the PCP field and the priority information of the ToS field in transmission frame information to be transmitted to the in-vehicle network, which is not used for determining the priority by the priority determination unit, according to a predetermined algorithm, and a reception information authentication unit that authenticates the received frame information when the other priority information in the received frame information has been rewritten according to the algorithm. Effect of the Invention

[0007] According to the vehicle communication device and the in-vehicle network system of the present invention, it is possible to enhance security while suppressing a decrease in performance and an increase in development costs of Ethernet-based communications on the in-vehicle network. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram for explaining an Ethernet frame format. [Diagram 2]1 is a diagram showing a schematic configuration of an in-vehicle network system according to a first embodiment of the present invention. [Diagram 3] 3 is a functional block diagram showing a configuration of a main part of an ECU in FIG. 2. [Figure 4] 5 is a flowchart showing an example of a filtering process of an Ethernet frame executed by a reception processing unit in the first embodiment. [Diagram 5] FIG. 11 is a diagram showing a schematic configuration of an in-vehicle network system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, since this is useful for understanding the present invention, an overview of Ethernet communications will be given with reference to FIG.

[0010] Generally, Ethernet is mainly used as a communication protocol between PCs and servers, and is assumed to be connected to various devices via routers that act as relays. For this reason, messages communicated between devices are generated according to the Ethernet frame format defined by IEEE802.3. As shown in the upper and lower parts of Figure 1, the items (fields) in the frame that can identify the communication partner in this frame format include the destination and source MAC (Media Access Control) addresses in the header and the destination and source IP (Internet Protocol) addresses in the IP header of the payload, and the source of the communication message can be identified by referring to these. For this reason, Ethernet communication has a security function called filtering that discards messages sent from MAC addresses and IP addresses other than the intended source at the receiving node.

[0011] Regarding the security function of Ethernet communication, there is also a function to virtually separate networks by using VLAN (Virtual Local Area Network) defined in IEEE802.1Q. In VLAN, as shown in the middle part of Figure 1, a VLAN tag is added between the source MAC address and the frame type in the header of the Ethernet frame format. A field called VID (VLAN Identifier) ​​is defined in the VLAN tag, and the identification information indicated by the VID can be used to determine which VLAN the port of the switch to which the source node is connected belongs to. If the source VLAN and destination VLAN are different, the Ethernet frame cannot be forwarded by an L2 (Layer 2) switch, which determines the forwarding destination by the destination MAC address, and will not reach the destination node unless it is forwarded by an L3 (Layer 3) switch, which determines the forwarding destination by the destination IP address. For this reason, security functions are improved by using VLANs.

[0012] As mentioned above, the application of in-vehicle Ethernet is progressing as a next-generation high-speed communication technology inside automobiles and other vehicles. In communication using in-vehicle Ethernet, it is possible to determine in advance the MAC address, IP address, and the presence or absence of a VLAN tag for devices with communication functions, such as electronic control units (ECUs) connected to the in-vehicle network. For this reason, in communication using in-vehicle Ethernet, the range of network use can be more limited than with the general Ethernet standard defined in IEEE802.3.

[0013] For example, assume that the in-vehicle network is designed under the condition that a MAC address and an IP address are assigned to each ECU mounted on the vehicle, and that Ethernet frames communicated within the vehicle must be assigned a VLAN tag. In this case, Ethernet frames that include a MAC address and an IP address that are not assigned to any ECU, or Ethernet frames that do not have a VLAN tag assigned, can be discarded as abnormal frames such as spoofed frames. In this way, in-vehicle Ethernet communication allows more detailed setting of conditions than general Ethernet communication, improving security functions.

[0014] However, because Ethernet communications within a vehicle use a standard frame format conforming to IEEE802.3, if a third party who understands this format can use equipment to monitor Ethernet frames to check the information within the frame, they can easily identify the MAC address, IP address, and the presence or absence of a VLAN tag, making it possible for them to spoof the information.

[0015] As a measure to prevent spoofing, authentication functions and encryption technologies such as MACsec and IPsec exist, but to support them, as mentioned above, common key management, encryption calculations, replacement of PHY transceivers, etc. are required, which increases development costs. Also, the additional data size caused by MACsec and IPsec encryption reduces the amount of data that can be transmitted in one frame (a reduction of 32 bytes for MACsec and a maximum of 36 bytes for IPsec). Furthermore, the additional encryption and decryption processes used by MACsec and IPsec have the disadvantage of slowing down communication speeds and causing processing delays.

[0016] The present invention provides a new technology for eliminating the disadvantages of such communications using in-vehicle Ethernet. Some embodiments of the present invention will be described in detail below with specific examples.

[0017] (First embodiment) FIG. 2 is a diagram showing a schematic configuration of an in-vehicle network system 1 according to the first embodiment of the present invention. In Fig. 2, an in-vehicle network system 1 is mounted on a vehicle such as an automobile. The in-vehicle network system 1 includes a plurality of electronic control units (ECUs) 2 mounted on the vehicle, and an in-vehicle network 3 that connects the ECUs 2 to each other. Each ECU 2 transmits and receives frame information conforming to the Ethernet protocol via the in-vehicle network 3. The frame information has a VLAN tag and an IP header as shown in the middle and lower parts of Fig. 1. The Ethernet frames communicated between the ECUs 2 will be described in detail later.

[0018] Each ECU 2 is assigned a MAC address as an identifier for identifying the ECU 2, and is assigned an IP address (private IP address) used only in the vehicle-mounted network 3 of the vehicle. In addition, a plurality of devices such as sensors and actuators are connected to each ECU 2. In the example of FIG. 2, the devices corresponding to the left ECU 2 are connected to the input / output ports of the ECU 2 using Ethernet cables (solid lines). On the other hand, the devices corresponding to the right ECU 2 are connected to the ECU 2 via a communication bus (dashed lines) that conforms to a protocol such as CAN (Controller Area Network) that is different from Ethernet. However, the communication method between the ECU 2 and each device is not limited to the above example, and any communication method according to the function of the ECU 2 can be adopted. The ECUs 2 are connected to each other by Ethernet cables.

[0019] FIG. 3 is a functional block diagram showing a configuration of a main part of the ECU 2 appearing in FIG. Each ECU 2 connected to an end node of the in-vehicle network 3 includes a transmission processing unit 21 and a reception processing unit 22 that process Ethernet frame information, as shown in Fig. 3. The transmission processing unit 21 generates frame information according to the Ethernet frame format (middle and lower parts of Fig. 1) and transmits the generated frame information onto the in-vehicle network 3. The reception processing unit 22 receives and processes frame information received from the in-vehicle network 3 according to the Ethernet frame format. In the first embodiment, the transmission processing unit 21 and the reception processing unit 22 of the ECU 2 realize a function equivalent to the "vehicle communication device" of the present invention.

[0020] Specifically, the transmission processing unit 21 generates an Ethernet frame in which transmission information, such as information detected by a sensor connected to the ECU 2 and information on the control state of an actuator, is stored in the data area of ​​the payload in order to transmit the transmission information to another ECU 2 on the in-vehicle network 3. In the header of this Ethernet frame, the following fields are set: destination MAC address, source MAC address, VLAN tag, and frame type, as shown in the middle part of Fig. 1.

[0021] The destination MAC address field stores a 6-byte value indicating the MAC address assigned to another ECU 2 that is the destination of the frame. The source MAC address field stores a 6-byte value indicating the MAC address assigned to the ECU 2 to which the transmission processing unit 21 belongs.

[0022] The VLAN tag field further contains the following fields: Tag Protocol Identifier (TPID), Priority Code Point (PCP), Canonical Format Indicator (CFI), and VLAN Identifier (VID). The TPID field stores a 16-bit value of "0x8100" which indicates that the frame is tagged according to IEEE802.1Q. The PCP field stores a 3-bit value (ranging from 0: lowest to 7: highest) which specifies the priority of the frame as defined by IEEE802.1p. The CFI field stores a 1-bit value of "0" which indicates that the MAC address is in the canonical format. The VID field stores a 12-bit value which indicates an identifier which specifies the VLAN to which the frame belongs.

[0023] The frame type field following the VLAN tag stores a two-byte value that indicates the higher-level protocol that is encapsulated in the payload of the Ethernet frame. In this case, a packet conforming to the higher-level protocol IP (Internet Protocol) is encapsulated in the payload of the Ethernet frame. In this case, the frame type field stores the value "0x0800" that indicates IPv4 (Internet Protocol version 4), or the value "0x86DD" that indicates IPv6 (Internet Protocol version 6). Below, we will explain the case where an IPv4 packet is encapsulated in the payload of an Ethernet frame as a specific example of an IP packet.

[0024] As shown in the lower part of Figure 1, the header of an IPv4 packet contains the following fields: version, header length, ToS (Type of Service), total length, identifier, flags, fragment position, TTL (Time to Live), protocol, checksum, source IP address, and destination IP address.

[0025] The version field stores a 4-bit value that indicates the version of the IP header. For IPv4, the value of the version field is "4". The header length field stores a 4-bit value that indicates the length of the IP header. The value of the header length field makes it possible to identify the start position of the payload in the IP packet.

[0026] The ToS (Type of Service) field further contains a 6-bit DSCP (Differentiated Services Code Point) field and a 2-bit ECN (Explicit Congestion Notification) field. The first 3 bits of the DSCP field store a value indicating the priority of the packet (from 0: lowest to 7: highest), and the remaining 3 bits of the DSCP field store a value indicating the discard priority. The ECN field stores a control value used for congestion control when network congestion occurs.

[0027] In a typical Ethernet frame, the priority information in the PCP field in the VLAN tag mentioned above and the priority information indicated by the ToS field in the IP header (the first 3 bits of the DSCP field) indicate a common value (one of eight levels ranging from 0: lowest to 7: highest). In other words, in the case of an Ethernet frame with a VLAN tag, there are two fields with the same function in the MAC header and IP header.

[0028] Therefore, in the transmission processing unit 21 in the first embodiment, the transmission information rewriting unit 21A shown in Fig. 3 performs processing to rewrite, according to a predetermined algorithm, the priority information that is not used for determining the priority by the priority determination unit 22A described later of the reception processing unit 22, among the overlapping priority information in the PCP field and the ToS field. Details of the processing by the transmission information rewriting unit 21A will be described later.

[0029] The total length field in the IP header contains a 16-bit value that indicates the total length of the IP packet's header and payload. The identifier field contains a 16-bit value that indicates information for identifying individual packets when a packet is fragmented. The flags field contains a 3-bit control value that is used to control fragmentation. The fragment position field contains a 13-bit value that indicates the position of the fragmented packet in the original packet.

[0030] The TTL (Time to Live) field contains an 8-bit value that indicates the amount of time the packet is permitted to exist on the network. The protocol field contains an 8-bit value that indicates the higher-level protocol encapsulated in the payload of the IP packet. The checksum field contains a 16-bit value that is used to check for errors in the IP header.

[0031] The source IP address field stores a 32-bit value indicating an IP address assigned to the ECU 2 to which the transmission processing unit 21 belongs. The destination IP address field stores a 32-bit value indicating an IP address assigned to another ECU 2 that is the destination of the IP packet.

[0032] The transmission processing unit 21 of the ECU 2 generates a message to be transmitted onto the in-vehicle network 3 in accordance with the above-mentioned VLAN tagged Ethernet frame format. At this time, the transmission information rewriting unit 21A provided as one functional component of the transmission processing unit 21 rewrites the priority information that is not used for determining the priority on the receiving side, out of the duplicated priority information stored in the PCP field in the VLAN tag and the ToS field in the IP header, in accordance with a predetermined algorithm.

[0033] The algorithm used by the transmission information rewriting unit 21A may be, for example, an algorithm that changes the value indicated by the priority information to be rewritten to a fixed value determined in advance, or an algorithm that changes the value according to a rule determined in advance based on the value indicated by the priority information to be rewritten. Alternatively, an algorithm that changes the value according to a rule determined in advance based on the value of a field other than the PCP field and the ToS field may be used.

[0034] To explain the process of the transmission information rewriting unit 21A according to the above algorithm in detail with some concrete examples, the transmission information rewriting unit 21A may set a value obtained by adding 1 to the value indicated by the priority information before rewriting as the value indicated by the priority information after rewriting. Also, the transmission information rewriting unit 21A may set a value opposite to the value indicated by the priority information before rewriting (for example, if the priority before rewriting is "6", the opposite priority is "1") as the value indicated by the priority information after rewriting.

[0035] Alternatively, the transmission information rewriting unit 21A can add the last byte of the destination MAC address and the last byte of the source MAC address based on the values ​​of the fields of the destination MAC address and the source MAC address in the Ethernet frame, extract the lowest 3 bits of the sum, and change the value indicated by the priority information to be rewritten to the extracted value. For example, if the destination MAC address is 00:00:00:10:00:0A and the source MAC address is 00:00:00:10:00:0B, the last byte is 0x0A and 0x0B, respectively, and these are added to each other to become 0x15. Since 0x15 is converted to binary to become 00010101, the lowest 3 bits are extracted to become 101 (0x05). Therefore, the transmission information rewriting unit 21A performs a process of rewriting the priority information that is not used for determining the priority on the receiving side to 101 (0x05) extracted by the above calculation.

[0036] Information regarding the algorithm used to rewrite the priority information as described above is shared in advance among devices provided at each node on the in-vehicle network 3. Specifically, in the first embodiment, the information is shared in advance among the transmission information rewriting unit 21A and the reception information authentication unit 22B of each ECU 2 provided at the end node of the in-vehicle network 3. The algorithm has a unique specification that differs from the way standard specifications are used in Ethernet, and therefore has the advantage of being difficult to decipher by a third party.

[0037] The Ethernet frame whose priority information has been rewritten by the transmission information rewriting unit 21A is transmitted from the transmission processing unit 21 onto the in-vehicle network 3 and received by the reception processing unit 22 of another ECU 2 connected to the in-vehicle network 3 (FIGS. 2 and 3). The reception processing unit 22 processes the received frame information in accordance with the above-mentioned Ethernet frame format.

[0038] Specifically, the reception processing unit 22 includes, as its functional components, the above-mentioned priority determination unit 22A and received information authentication unit 22B (FIG. 3). The priority determination unit 22A determines the priority of an Ethernet frame received from the in-vehicle network 3 using one of the priority information in the PCP field in the VLAN tag and the priority information in the ToS field in the IP header.

[0039] Which of the priority information in the PCP field and the ToS field is used for determining the priority can be arbitrarily selected in accordance with the settings of the L2 switch and / or the L3 switch that may be connected to the in-vehicle network 3. Here, of the priority information in the PCP field and the ToS field, one of the priority information used for determining the priority and the other priority information not used for determining the priority are uniquely determined for the entire in-vehicle network 3.

[0040] The received information authentication unit 22B determines whether the other priority information in the Ethernet frame (received frame information) received from the in-vehicle network 3, which is not used for determining the priority by the priority determination unit 22A, has been rewritten according to the above-mentioned algorithm. If it has been rewritten according to the algorithm, the received information authentication unit 22B authenticates the Ethernet frame. On the other hand, if it has not been rewritten according to the algorithm, the received information authentication unit 22B discards the Ethernet frame. Such authentication processing based on the priority information in the received information authentication unit 22B is executed as part of the filtering processing of the Ethernet frame.

[0041] FIG. 4 is a flowchart showing an example of filtering processing of an Ethernet frame executed by the reception processing unit 22. As shown in FIG. When an Ethernet frame transmitted through the in-vehicle network 3 is received by the reception processing unit 22 of the ECU 2, first in step S10 of Fig. 4, the reception processing unit 22 checks the header information (including the IP header) of the Ethernet frame. In the following step S20, the reception processing unit 22 determines whether the destination MAC address and destination IP address in the header information are correct addresses corresponding to its own node. If the destination MAC address and destination IP address are correct (YES), the process proceeds to the next step S30. On the other hand, if the destination MAC address or destination IP address is incorrect (NO), the process proceeds to step S70, where the reception processing unit 22 discards the Ethernet frame.

[0042] In step S30, the reception processing unit 22 determines whether or not the source MAC address and source IP address in the header information are correct addresses assigned to any of the devices on the in-vehicle network 3. If the source MAC address and source IP address are correct (YES), the process proceeds to the next step S40. On the other hand, if the source MAC address or source IP address is incorrect (NO), the process proceeds to the above-mentioned step S70, where the Ethernet frame is discarded.

[0043] In step S40, the reception processing unit 22 determines whether or not a VLAN tag is added to the header of the Ethernet frame. If a VLAN tag is added (YES), the process proceeds to the next step S50. On the other hand, if a VLAN tag is not added (NO), the process proceeds to the above-mentioned step S70, where the Ethernet frame is discarded.

[0044] In step S50, the received information authentication unit 22B determines whether or not the priority information not used by the priority determination unit 22A has been rewritten in accordance with the algorithm shared by each node on the in-vehicle network 3. If the priority information has been rewritten in accordance with the algorithm (YES), the process proceeds to step S60, where the received information authentication unit 22B authenticates the Ethernet frame. On the other hand, if the priority information has not been rewritten in accordance with the algorithm (NO), the process proceeds to the above-mentioned step S70, where the Ethernet frame is discarded.

[0045] As a result of the filtering process of the Ethernet frame in the reception processing unit 22 as described above, the Ethernet frame is not authenticated on the receiving side unless the algorithm used in the rewriting process for the priority information not used in determining the priority is known, thereby enhancing the security of Ethernet communications on the in-vehicle network 3. Note that for the Ethernet frame authenticated by the filtering process, the reception processing unit 22 continues to execute a well-known reception process including the priority determination in the priority determination unit 22A described above.

[0046] As described above, in the in-vehicle network system 1 of the first embodiment, of the overlapping priority information in the PCP field in the VLAN tag and the ToS field in the IP header in the Ethernet frame, one of the priority information is used to determine the priority, and the other priority information is used to authenticate the received frame information based on rewriting according to a predetermined algorithm. This makes it possible to improve the security function of the Ethernet communication on the in-vehicle network 3 without causing an increase in data size, an increase in development costs, a decrease in communication speed, and a processing delay that are associated with conventional encryption. In other words, according to the in-vehicle network system 1 of the first embodiment, it is possible to strengthen security while suppressing development costs without degrading the performance of the Ethernet communication between each ECU connected to the in-vehicle network 3.

[0047] In particular, if the above algorithm defines rules for rewriting priority information based on the destination MAC address and source MAC address included in the Ethernet frame, it is possible to further strengthen security while making each process in the transmission information rewriting unit 21A and the reception information authentication unit 22B relatively simple. That is, although a complex calculation formula can be set as an algorithm for rewriting priority information, it is possible to simplify the process by using the MAC address or IP address assigned to each ECU 2. In this case, assuming that an ECU is retrofitted to the in-vehicle network 3, the IP address of the retrofitted ECU may be automatically set, and the process of rewriting priority information using the IP address may become complicated. On the other hand, since the MAC address is set uniquely for each ECU, the process of rewriting priority information using the MAC address becomes relatively simple as shown in the above specific example. Therefore, by rewriting priority information based on the destination MAC address and source MAC address included in the Ethernet frame, it is possible to improve security while avoiding the process from becoming complicated.

[0048] Second embodiment Next, an in-vehicle network system according to a second embodiment of the present invention will be described. FIG. 5 is a diagram showing a schematic configuration of an in-vehicle network system 1 according to the second embodiment. 5, in the in-vehicle network system 1 of the second embodiment, five systems of ECUs 2, namely, an ADAS (Advanced Driving Assistant System) system, a powertrain system, a body system, a chassis system, and an IVI (In-Vehicle Infotainment) system, are connected to an in-vehicle network 3. In addition, a relay unit 4 is disposed on the in-vehicle network 3, and Ethernet frames transmitted and received between the ECUs 2 of each system are relayed and transmitted by the relay unit 4.

[0049] The ECU 2 of each system is assigned a MAC address and an IP address in advance, as in the first embodiment described above. To each ECU 2 of the ADAS system and the IVI system, various devices such as a camera, a radar, a navigation system, etc. are connected via Ethernet cables (solid lines). Each ECU 2 of the ADAS system and the IVI system has a function as an L2 switch that switches the connection between ports based on a MAC address. To each ECU 2 of the powertrain system, the body system, and the chassis system, a plurality of various devices such as sensors and actuators are connected via a communication bus (dashed lines) such as a CAN. Each ECU 2 of the powertrain system, the body system, and the chassis system has a function as a gateway that performs protocol conversion.

[0050] The relay unit 4 has a plurality of ports corresponding to the ECU 2 of each system. The ECU 2 of each system is connected to each port of the relay unit 4 using an Ethernet cable. The relay unit 4 has a function as an L3 switch (router) that routes information based on an IP address. In addition to the ECU 2 of each system, for example, a fault diagnosis device outside the vehicle and a wireless communication unit for connecting to a communication network outside the vehicle may be connected to the relay unit 4 using an Ethernet cable. Also, a plurality of relay units 4 can be installed on the in-vehicle network 3.

[0051] The ECU 2 and relay unit 4 of each system respectively include a transmission processing unit 21 and a reception processing unit 22 for processing Ethernet frame information, similarly to the first embodiment described above (FIG. 3). That is, in the second embodiment, the ECU 2 and relay unit 4 of each system respectively perform the processes by the transmission information rewriting unit 21A, the priority determination unit 22A, and the reception information authentication unit 22B as described in the first embodiment.

[0052] In the in-vehicle network system 1 of the second embodiment as described above, Ethernet frames are transmitted and received between various ECUs 2 of different systems mounted on the vehicle via the in-vehicle network 3 and the relay unit 4. At this time, filtering of the Ethernet frames (FIG. 4) similar to that in the first embodiment described above is performed in each of the end nodes and relay nodes on the in-vehicle network 3. This makes it possible to strengthen security while suppressing development costs without degrading the performance of Ethernet communications via the relay unit 4 on the wide-ranging in-vehicle network 3.

[0053] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications and changes are possible based on the technical concept of the present invention. For example, in the above-mentioned embodiment, an example in which an IPv4 packet is encapsulated in the payload of an Ethernet frame has been described, but the present invention is also effective in the case in which an IPv6 packet is encapsulated in the payload of an Ethernet frame. In this case, the Traffic Class field in the IPv6 header corresponds to the ToS field in the IPv4 header. [Explanation of symbols]

[0054] 1. In-vehicle network system 2...Electronic control unit (ECU) 21...Transmission processing unit 21A…Transmission information rewriting unit 22...Receiving processing unit 22A...Priority determination section 22B…Received information authentication section 3…In-vehicle network 4...Relay unit

Claims

1. A vehicle communication device that transmits and receives frame information having a VLAN tag and an IP header in accordance with an Ethernet (registered trademark) protocol on an in-vehicle network mounted in a vehicle, comprising: a priority determination unit that determines a priority of the received frame information by using one of priority information of a PCP field in the VLAN tag and priority information of a ToS field in the IP header in the received frame information received from the in-vehicle network; a transmission information rewriting unit that rewrites the other priority information, which is not used for determining the priority by the priority determination unit, of the priority information of the PCP field and the priority information of the ToS field in the transmission frame information to be transmitted to the in-vehicle network according to a predetermined algorithm; a reception information authenticating unit that authenticates the reception frame information when the other priority information in the reception frame information has been rewritten according to the algorithm; A vehicle communication device comprising:

2. 2. The vehicle communication device according to claim 1, wherein the algorithm defines a rule for rewriting the other priority information based on a destination MAC address and a source MAC address included in the frame information.

3. A plurality of electronic control units mounted on a vehicle; an in-vehicle network that is mounted on the vehicle and connects the plurality of electronic control units to each other; An in-vehicle network system in which the plurality of electronic control units transmit and receive frame information having a VLAN tag and an IP header in accordance with an Ethernet protocol via the in-vehicle network, Each of the plurality of electronic control units is a priority determination unit that determines a priority of the received frame information by using one of priority information of a PCP field in the VLAN tag and priority information of a ToS field in the IP header in the received frame information received from the in-vehicle network; a transmission information rewriting unit that rewrites the other priority information, which is not used for determining the priority by the priority determination unit, of the priority information of the PCP field and the priority information of the ToS field in the transmission frame information to be transmitted to the in-vehicle network according to a predetermined algorithm; a reception information authenticating unit that authenticates the reception frame information when the other priority information in the reception frame information has been rewritten according to the algorithm; An in-vehicle network system including:

4. The in-vehicle network system according to claim 3 , further comprising at least one relay unit arranged on the in-vehicle network, which relays the frame information transmitted and received between the plurality of electronic control units.

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