Naive incomplete chunk header packer

src/chunks.asm

@@ -0,0 +1,79 @@
+pack_chunk_header:
+    ; pack_chunk_header [rax] [rdi] [rsi]
+    ;   rax = flags
+    ;   rdi = size
+    ;   rsi = output buffer
+    ;
+    ; example:
+    ;
+    ;  mov rax, 0
+    ;  set_rax_flag CHUNKFLAG_VITAL
+    ;  mov rdi, 10
+    ;  mov rsi, my_chunk_buffer
+    ;  call pack_chunk_header
+    ;
+
+    push rax
+
+    cmp rdi, 63
+    jg .pack_chunk_header_error_size
+
+    push rax
+    mov dword rax, [connection_sequence]
+    cmp rax, 255
+    jg .pack_chunk_header_error_seq
+    pop rax
+
+    ; Chunk header (vital)
+    ; +---------+---------+-----------------+--------+-----------------+
+    ; | Flags   | Size    | Sequence number | Size   | Sequence number |
+    ; | 2 bits  | 6 bits  | 2 bits          | 6 bits | 8 bits          |
+    ; +---------+---------+-----------------+--------+-----------------+
+
+    ; flags
+    mov [rsi], al
+    ; size (only in the 2nd byte for now)
+    mov [rsi+1], dil
+
+    ; sequence only included if it is a vital chunk
+    is_rax_flag CHUNKFLAG_VITAL
+    jz .pack_chunk_header_end
+
+    ; sequence (only in the 3rd byte for now)
+    mov byte al, [connection_sequence]
+    mov [rsi+2], al
+
+    jmp .pack_chunk_header_end
+
+.pack_chunk_header_error_seq:
+    print s_unsupported_seq_size
+    mov rax, [connection_sequence]
+    call print_uint32
+    exit 1
+
+.pack_chunk_header_error_size:
+    print s_unsupported_chunk_size
+    mov rax, rdi
+    call print_uint32
+    exit 1
+
+.pack_chunk_header_end:
+    pop rax
+    ret
+
+queue_chunk:
+    ; queue_chunk [rax] [rdi] [rsi] [rdx]
+    ;  rax = system (1=system 0=game)
+    ;  rdi = payload
+    ;  rsi = payload size
+
+    ; resend flag is not supported yet
+
+    push_registers
+
+    ; increment if vital
+    ; connection_sequence
+
+    pop_registers
+    ret
+

src/data/logger.asm

@@ -3,3 +3,6 @@ char_space   db 0x20
 
 s_dbg_rax_digit db "[debug] value of rax is: ", 0
 l_s_dbg_rax_digit equ $ - s_dbg_rax_digit
+
+s_dbg_reg_digit db "[debug] value of register is: ", 0
+l_s_dbg_reg_digit equ $ - s_dbg_reg_digit

src/data/teeworlds.asm

@@ -21,6 +21,9 @@ PACKETFLAG_RESEND equ 0b00_0010_00
 PACKETFLAG_COMPRESSION equ 0b00_0100_00
 PACKETFLAG_CONNLESS equ 0b00_1000_00
 
+CHUNKFLAG_VITAL equ 0b0100_0000
+CHUNKFLAG_RESEND equ 0b1000_0000
+
 token db 0xDD, 0xDD, 0xCC, 0xCC
 peer_token db 0xFF, 0xFF, 0xFF, 0xFF
 

src/data/teeworlds_strings.asm

@@ -0,0 +1,16 @@
+s_got_peer_token db "[client] got peer token: "
+l_s_got_peer_token equ $ - s_got_peer_token
+s_got_accept db "[client] got accept", 0x0a
+l_s_got_accept equ $ - s_got_accept
+s_got_ctrl_msg db "[client] got ctrl msg: "
+l_s_got_ctrl_msg equ $ - s_got_ctrl_msg
+s_unknown_ctrl_msg db "[client] unknown ctrl msg: "
+l_s_unknown_ctrl_msg equ $ - s_unknown_ctrl_msg
+s_got_packet_with_chunks db "[client] got packet with chunks: "
+l_s_got_packet_with_chunks equ $ - s_got_packet_with_chunks
+s_unhandled_packet db "[client] UNHANDLED PACKET!!"
+l_s_unhandled_packet equ $ - s_unhandled_packet
+s_unsupported_chunk_size db "[error] chunk sizes higher than 63 are not supported yet. got size: "
+l_s_unsupported_chunk_size equ $ - s_unsupported_chunk_size
+s_unsupported_seq_size db "[error] chunk sequence numbers higher than 255 are not supported yet. got sequence number: "
+l_s_unsupported_seq_size equ $ - s_unsupported_seq_size

src/macros.asm

@@ -29,6 +29,40 @@
     pop_registers
 %endmacro
 
+%macro is_rax_flag 1
+    ; is_rax_flag [teeworlds bit flag constant]
+    ;
+    ; example:
+    ;
+    ;  mov rax, [udp_recv_buf]
+    ;  is_rax_flag PACKETFLAG_CONTROL
+    ;  jnz on_ctrl_message
+    ;
+    ; no idea if this "if statement" is correct
+    push rax
+    and al, %1
+    cmp al, 0
+    pop rax
+%endmacro
+
+%macro set_rax_flag 1
+    ; set_rax_flag [teeworlds bit flag constant]
+    ;
+    ; sets a bit flag
+    ;
+    ; example:
+    ;
+    ;  mov rax, 0
+    ;  set_rax_flag CHUNKFLAG_VITAL
+    ;
+    push rcx
+
+    mov cl, %1
+    or al, cl
+
+    pop rcx
+%endmacro
+
 %macro push_registers 0
     push rax
     push rbx

src/teeworlds_asmr.asm

@@ -87,6 +87,7 @@ section .data
     %include "src/data/posix.asm"
     %include "src/data/syscalls.asm"
     %include "src/data/teeworlds.asm"
+    %include "src/data/teeworlds_strings.asm"
     %include "src/data/terminal.asm"
     %include "src/data/logger.asm"
     %include "src/data/hex.asm"
@@ -113,8 +114,6 @@ section .data
     l_s_you_pressed_a equ $ - s_you_pressed_a
     s_you_pressed_d db "you pressed d",0x0a
     l_s_you_pressed_d equ $ - s_you_pressed_d
-    s_dbg_reg_digit db "[debug] value of register is: ", 0
-    l_s_dbg_reg_digit equ $ - s_dbg_reg_digit
     s_got_file_desc db "got file descriptor: "
     l_s_got_file_desc equ $ - s_got_file_desc
     s_got_udp db "[client] got udp: "
@@ -130,20 +129,6 @@ section .data
     s_packer_size db "[packer] amount of bytes packed: "
     l_s_packer_size equ $ - s_packer_size
 
-    ; teeworlds strings
-    s_got_peer_token db "[client] got peer token: "
-    l_s_got_peer_token equ $ - s_got_peer_token
-    s_got_accept db "[client] got accept", 0x0a
-    l_s_got_accept equ $ - s_got_accept
-    s_got_ctrl_msg db "[client] got ctrl msg: "
-    l_s_got_ctrl_msg equ $ - s_got_ctrl_msg
-    s_unknown_ctrl_msg db "[client] unknown ctrl msg: "
-    l_s_unknown_ctrl_msg equ $ - s_unknown_ctrl_msg
-    s_got_packet_with_chunks db "[client] got packet with chunks: "
-    l_s_got_packet_with_chunks equ $ - s_got_packet_with_chunks
-    s_unhandled_packet db "[client] UNHANDLED PACKET!!"
-    l_s_unhandled_packet equ $ - s_unhandled_packet
-
 section .bss
     %include "src/bss/hex.asm"
     %include "src/bss/teeworlds.asm"

tests/assert.asm

@@ -5,6 +5,8 @@ section .data
     %include "src/data/syscalls.asm"
     %include "src/data/logger.asm"
     %include "src/data/hex.asm"
+    %include "src/data/teeworlds.asm"
+    %include "src/data/teeworlds_strings.asm"
 
     s_assert_ok db "[assert] OK", 0x0a
     l_s_assert_ok equ $ - s_assert_ok

tests/chunk_test.asm

@@ -0,0 +1,20 @@
+%include "tests/assert.asm"
+%include "src/chunks.asm"
+
+_start:
+    mov dword [connection_sequence], 9
+
+    mov rax, 0
+    set_rax_flag CHUNKFLAG_VITAL
+    mov rdi, 6
+    mov rsi, assert_actual_buf
+    call pack_chunk_header
+
+    mov al, [assert_actual_buf]
+    assert_al_eq 0x40
+    mov al, [assert_actual_buf + 1]
+    assert_al_eq 0x06
+    mov al, [assert_actual_buf + 2]
+    assert_al_eq 0x09
+    exit 0
+