Changes in source, destination IP address, and MAC address when data packets are forwarded through a route

Changes in the source IP address, destination ip address, and MAC address of a data packet during route forwarding. Does the source ip address, destination IP address, source MAC address, and destination mac change? A -- (B1-B2) -- (C1-C2) --- E as an example above, B1 and B2 are two interfaces on router B, C1 and C2 are two interfaces on router C, A and E are PCs. When host A sends data packets to host E, the destination IP address of the data packet formed by host A is the IP address of host E, and the source IP address is the IP address of host, the target MAC address is the MAC address of B1. The source MAC address is the MAC address of A, which is sent from A to router B. After B is reencapsulated, the source IP address and target IP address remain unchanged, the source MAC address is changed to the B2 MAC address, the target MAC address is changed to the C1 MAC address, and the package is encapsulated and sent to router C. After receiving the data packet, router C performs the same operations as B, if the source IP address and target IP address remain unchanged, the source MAC address is changed to the C2 MAC address, the target MAC address is changed to the MAC address of host E, and then sent to host E, E then receives the packet. When the packet is restored, the source IP address (the IP address of host A) and the source MAC address (the MAC address of interface C2) of the received packet are) as the target IP address and target MAC address