From b7a2cfb5c36762d0c67ceb72fec87729dc61b926 Mon Sep 17 00:00:00 2001
From: ChillerDragon <ChillerDragon@gmail.com>
Date: Sun, 30 Oct 2022 19:00:13 +0100
Subject: [PATCH] Start working on proper packet header

---
 lib/chunk.rb   | 10 ++++++++-
 lib/network.rb |  2 ++
 lib/packet.rb  | 58 ++++++++++++++++++++++++++++++++++++--------------
 teeworlds.rb   | 34 +++++++++++++++++++++++++++--
 4 files changed, 85 insertions(+), 19 deletions(-)

diff --git a/lib/chunk.rb b/lib/chunk.rb
index 1b983bb..3e45a55 100644
--- a/lib/chunk.rb
+++ b/lib/chunk.rb
@@ -3,7 +3,7 @@ require_relative 'network'
 require_relative 'bytes'
 
 class NetChunk
-  attr_reader :next, :data, :msg, :sys
+  attr_reader :next, :data, :msg, :sys, :flags
 
   def initialize(data)
     @next = nil
@@ -37,6 +37,14 @@ class NetChunk
     # sequence number
     # in da third byte but who needs seq?!
   end
+
+  def flags_vital
+    @flags[:vital]
+  end
+
+  def flags_resend
+    @flags[:resend]
+  end
 end
 
 MAX_NUM_CHUNKS = 1024
diff --git a/lib/network.rb b/lib/network.rb
index 0268b18..0bac43f 100644
--- a/lib/network.rb
+++ b/lib/network.rb
@@ -79,6 +79,8 @@ NET_CTRLMSG_ACCEPT = 2
 NET_CTRLMSG_CLOSE = 4
 NET_CTRLMSG_TOKEN = 5
 
+NET_MAX_SEQUENCE = 1<<10
+
 NET_CONNSTATE_OFFLINE = 0
 NET_CONNSTATE_TOKEN = 1
 NET_CONNSTATE_CONNECT = 2
diff --git a/lib/packet.rb b/lib/packet.rb
index f8c2b6c..2ab73c3 100644
--- a/lib/packet.rb
+++ b/lib/packet.rb
@@ -1,5 +1,46 @@
 require 'huffman_tw'
 
+class PacketFlags
+  attr_reader :bits, :hash
+
+  def initialize(data)
+    @hash = {}
+    @bits = ''
+    if data.class == Hash
+      @bits = parse_hash(data)
+      @hash = data
+    elsif data.class == String
+      @hash = parse_bits(data)
+      @bits = data
+    else
+      raise "Flags have to be hash or string"
+    end
+  end
+
+  def parse_hash(hash)
+    bits = ''
+    bits += hash[:connection] == '1' ? '1' : '0'
+    bits += hash[:compressed] == '1' ? '1' : '0'
+    bits += hash[:resend] == '1' ? '1' : '0'
+    bits += hash[:control] == '1' ? '1' : '0'
+    bits
+  end
+
+  def parse_bits(four_bit_str)
+    # takes a 4 character string
+    # representing the middle of the first byte sent
+    # in binary representation
+    #
+    # and creates a hash out of it
+    hash = {}
+    hash[:connection] = four_bit_str[0] == '1'
+    hash[:compressed] = four_bit_str[1] == '1'
+    hash[:resend] = four_bit_str[2] == '1'
+    hash[:control] = four_bit_str[3] == '1'
+    hash
+  end
+end
+
 # Class holding the parsed packet data
 class Packet
   attr_reader :flags, :payload
@@ -14,10 +55,9 @@ class Packet
     #         network direction (client/server)
     @prefix = prefix
     @huffman = Huffman.new
-    @flags = {}
     @data = data
     flags_byte = @data[0].unpack("B*")
-    parse_flags(flags_byte.first[2..5])
+    @flags = PacketFlags.new(flags_byte.first[2..5]).hash
     @payload = @data[PACKET_HEADER_SIZE..]
     if flags_compressed
       @payload = @huffman.decompress(@payload.unpack("C*"))
@@ -51,20 +91,6 @@ class Packet
     puts ""
   end
 
-  def parse_flags(four_bit_str)
-    # takes a 4 character string
-    # representing the middle of the first byte sent
-    # in binary representation
-    #
-    # and creates a hash out of it
-    @flags = {}
-    @flags[:connection] = four_bit_str[0] == '1'
-    @flags[:compressed] = four_bit_str[1] == '1'
-    @flags[:resend] = four_bit_str[2] == '1'
-    @flags[:control] = four_bit_str[3] == '1'
-    @flags
-  end
-
   def flags_compressed()
     @flags[:compressed]
   end
diff --git a/teeworlds.rb b/teeworlds.rb
index f83efa1..dd9c4b0 100755
--- a/teeworlds.rb
+++ b/teeworlds.rb
@@ -11,25 +11,51 @@ require_relative 'lib/chunk'
 require_relative 'lib/server_info'
 
 class NetBase
-  attr_accessor :client_token, :server_token
+  attr_accessor :client_token, :server_token, :ack
 
   def initialize
     @ip = nil
     @port = nil
     @s = nil
+    @ack = 0
   end
 
   def connect(socket, ip, port)
     @s = socket
     @ip = ip
     @port = port
+    @ack = 0
   end
 
   ##
   # Sends a packing setting the proper header for you
   #
   # @param payload [Array] The Integer list representing the data after the header
-  def send_packet(payload)
+  # @param flags [Hash] Packet header flags for more details check the class +PacketFlags+
+  def send_packet(payload, flags = {})
+    # unsigned char flags_ack;    // 6bit flags, 2bit ack
+    # unsigned char ack;          // 8bit ack
+    # unsigned char numchunks;    // 8bit chunks
+    # unsigned char token[4];     // 32bit token
+    # // ffffffaa
+    # // aaaaaaaa
+    # // NNNNNNNN
+    # // TTTTTTTT
+    # // TTTTTTTT
+    # // TTTTTTTT
+    # // TTTTTTTT
+    flags_bits = PacketFlags.new(flags).bits
+    header_bits =
+      '00' + # unused flags?      # ff
+      flags_bits +                # ffff
+      @ack.to_s(2).rjust(10, '0') # aa aaaa aaaa
+
+    puts "header bits: #{header_bits}"
+    header = header_bits.chars.groups_of(4).map do |four_bits|
+      four_bits.join('').to_i(2)
+    end
+    puts "header bytes: #{str_hex(header.pack("C*"))}"
+
     header = [0x00, 0x00, 0x01] + str_bytes(@server_token)
     data = (header + payload).pack('C*')
     @s.send(data, 0, @ip, @port)
@@ -212,6 +238,10 @@ class TwClient
   def process_server_packet(data)
     chunks = BigChungusTheChunkGetter.get_chunks(data)
     chunks.each do |chunk|
+      if chunk.flags_vital
+        @netbase.ack = (@netbase.ack + 1) % NET_MAX_SEQUENCE
+        puts "got ack: #{@netbase.ack}"
+      end
       process_chunk(chunk)
     end
   end