汇编中的echo客户端

Question

我正在学习一些汇编语言。在这样做的过程中，我试图在nasm程序集中编写一个带有TCP套接字的echo客户端/服务器。我已经用各种其他语言（如C和java）完成了套接字编程，并尝试使其在汇编中工作。我找到了几个用汇编编写的服务器代码示例，但没有给客户带来太多好运。

我在这里查看了服务器示例：https://gist.github.com/bobbo/e1e980262f2ddc8db3b8

服务器正常工作，我正在尝试编辑它以将其转换为客户端。

这是我到目前为止所拥有的。似乎无法弄清楚在何处放入连接套接字，发送数据和接收数据的指令。

 global _start

;; Data definitions
 struc sockaddr_in
.sin_family resw 1
.sin_port resw 1
.sin_addr resd 1
.sin_zero resb 8
endstruc

 section .bss
sock resw 2
client resw 2
echobuf resb 256
read_count resw 2

section .data

sock_err_msg        db "Failed to initialize socket", 0x0a, 0
sock_err_msg_len    equ $ - sock_err_msg

connect_err_msg        db "Failed to connect socket", 0x0a, 0
connect_err_msg_len    equ $ - connect_err_msg

;; sockaddr_in structure for the address the listening socket binds to
pop_sa istruc sockaddr_in
    at sockaddr_in.sin_family, dw 2           ; AF_INET
    at sockaddr_in.sin_port, dw 0xce56        ; port 22222 in host byte order
    at sockaddr_in.sin_addr, dd 0             ; localhost - INADDR_ANY
    at sockaddr_in.sin_zero, dd 0, 0
iend
sockaddr_in_len     equ $ - pop_sa


 section .text

 ;; Client main entry point
_start:
;; Initialize socket value to 0, used for cleanup 
mov      word [sock], 0

;; Initialize socket
call     _socket

;; Performs a sys_socket call to initialise a TCP/IP socket. 
;; Stores the socket file descriptor in the sock variable
_socket:
mov         rax, 41     ; SYS_SOCKET
mov         rdi, 2      ; AF_INET
mov         rsi, 1      ; SOCK_STREAM
mov         rdx, 0    
syscall

;; Check if socket was created successfully
cmp        rax, 0
jle        _socket_fail

;; Store the new socket descriptor 
mov        [sock], rax

ret

;; Performs sys_close on the socket in rdi
_close_sock:
mov     rax, 3        ; SYS_CLOSE
syscall

ret

;; Error Handling code
;; _*_fail loads the rsi and rdx registers with the appropriate
;; error messages for given system call. Then call _fail to display the
;; error message and exit the application.
_socket_fail:
   mov     rsi, sock_err_msg
   mov     rdx, sock_err_msg_len
   call    _fail

;; Calls the sys_write syscall, writing an error message to stderr, then 
;; exits
;; the application. rsi and rdx must be loaded with the error message and
;; length of the error message before calling _fail
_fail:
mov        rax, 1 ; SYS_WRITE
mov        rdi, 2 ; STDERR
syscall

mov        rdi, 1
call       _exit

 ;; Exits cleanly, checking if the listening or client sockets need to be 
 ;; closed
 ;; before calling sys_exit
_exit:
mov        rax, [sock]
cmp        rax, 0
je         .client_check
mov        rdi, [sock]
call       _close_sock

.client_check:
mov        rax, [client]
cmp        rax, 0
je         .perform_exit
mov        rdi, [client]
call       _close_sock

.perform_exit:
mov        rax, 60
syscall