WARNING: Mac address to reach destination not found. Using broadcast

这是一个网络通信中的警告信息，意思是无法找到用于到达目标地址的 MAC 地址，因此使用广播方式发送信息。在网络通信中，每个设备都有一个唯一的 MAC 地址，用于标识设备的物理地址。当一台设备需要发送数据到另一台设备时，需要知道目标设备的 MAC 地址才能够正确地发送数据。如果无法找到目标设备的 MAC 地址，就需要使用广播方式发送数据，这样所有与网络相连的设备都会接收到该数据包。

相关问题

INFO: Can't import matplotlib. Won't be able to plot. INFO: Can't import PyX. Won't be able to use psdump() or pdfdump(). WARNING: No route found for IPv6 destination :: (no default route?) INFO: Can't import python ecdsa lib. Disabled certificate manipulation tools Welcome to Scapy (2.3.3)

这是Scapy软件的启动信息，其中包含了一些提示和警告信息。具体来说：

- "Can't import matplotlib. Won't be able to plot." 表示Scapy无法导入matplotlib库，因此无法进行绘图操作。
- "Can't import PyX. Won't be able to use psdump() or pdfdump()." 表示Scapy无法导入PyX库，因此无法使用psdump()或pdfdump()方法来保存Scapy绘制的图像。
- "WARNING: No route found for IPv6 destination :: (no default route?)" 表示Scapy在IPv6地址上找不到默认路由，可能会影响网络连接。
- "Can't import python ecdsa lib. Disabled certificate manipulation tools" 表示Scapy无法导入python ecdsa库，因此禁用了证书操作工具。

Write a procedure that copys a string to another memory location.The procedurereceives two parameters:the start address of the source string and the start addressof the destination memory location.Write a test program that calls your procedureand shows the copied string in the destination memory location after the call. Requirement:Your code should be assembled and executed successfully.Submit thefile of your source code.2021

Sure, here is a possible implementation of the procedure in x86 assembly language:

section .text
global copy_string

copy_string:
    push ebp
    mov ebp, esp
    push ebx
    push ecx
    push edx

    mov ebx, [ebp+8] ; source address
    mov ecx, [ebp+12] ; destination address

    mov al, [ebx] ; load first byte from source
    mov [ecx], al ; store first byte to destination
    inc ebx
    inc ecx

.copy_loop:
    mov al, [ebx] ; load next byte from source
    mov [ecx], al ; store next byte to destination
    inc ebx
    inc ecx
    cmp byte [ebx-1], 0 ; check if end of string
    jne .copy_loop

    pop edx
    pop ecx
    pop ebx
    mov esp, ebp
    pop ebp
    ret

This procedure uses the standard x86 calling convention, where the first parameter (source address) is passed in the `eax` register and the second parameter (destination address) is passed in the `edx` register. The procedure copies the string byte by byte from the source to the destination, until it reaches the end of the string (indicated by a null byte).

Here is an example program that calls the `copy_string` procedure and displays the copied string:

section .data
source db "Hello, world!", 0
destination times 13 db 0 ; reserve space for copied string

section .text
global _start

_start:
    ; call copy_string procedure with source and destination addresses
    push dword destination
    push dword source
    call copy_string
    add esp, 8

    ; display copied string
    mov eax, 4 ; write system call
    mov ebx, 1 ; standard output file descriptor
    mov ecx, destination ; address of copied string
    mov edx, 13 ; length of string
    int 0x80 ; invoke system call

    ; exit program
    mov eax, 1 ; exit system call
    xor ebx, ebx ; exit status 0
    int 0x80 ; invoke system call

This program defines a string `source` and a destination buffer `destination`, and calls the `copy_string` procedure with their addresses. Then it displays the copied string using the `write` system call, and exits with a status of 0.

To assemble and link this program, you can use the following commands (assuming you save the code in a file called `copy.asm`):

nasm -f elf32 -o copy.o copy.asm
ld -m elf_i386 -o copy copy.o

This will produce an executable file called `copy`, which you can run by typing `./copy` in the terminal.