This server allows client side connections to play in a round robin blackjack table where each player plays one hand at a time with the ability to Bet, Hit and Stay. Players are removed when they run out of money. Messaging was built in however, remains untested as the client did not support the functionality. The server and client use a protocol which was designed as part of the assignment by the class. The client is currently not available here as I am working on getting permission for the executable or the code.
Protocol Description
All multibyte integers are transmitted in network byte order, i.e., big endian.
Connect Request (size 13B)
1 B: Connect Request
12 B: Username: if the username has fewer than 12 characters, it must be a NUL-terminated string
Response: State (below) OR Error
the Username must appear at a seat
if mid-round, player will not be a "Player to Respond" until the next round
State (size 320B)
1 B: State Update (Opcode)
4 B: Response Arguments (0 for “State”)
2 B: Seq. # (+1 as the game progresses)
4 B: Minimum Bet
1 B: Player to Respond (0 is dealer; 1-based index into array below)
21 B: Dealer Cards
7 times…
12 B: Username
4 B: Bank
4 B: Bet
21 B: Cards
Client Response:
Player to Respond: Bet, Stand, or Hit (below)
If player’s Bet field is empty → Bet
Otherwise → Stand or Hit
Other Players: None
Note: State is sent out 3 times at the end of a round with the dealer’s cards; 1 second separates messages
The assignment bytes: <- sick joke
Layout
0 1 5 7 11
| opcode | Response Args | Seq # | Min Bet |
11 12 33
| Active Player | Dealer Cards |
33 45 49 53 74
P1 | Username | Bank | Bet | Cards |
74 86 90 94 115
P2 | Username | Bank | Bet | Cards |
115 127 131 135 156
P3 | Username | Bank | Bet | Cards |
156 168 172 176 197
P4 | Username | Bank | Bet | Cards |
197 209 213 217 238
P5 | Username | Bank | Bet | Cards |
238 250 254 258 279
P6 | Username | Bank | Bet | Cards |
279 291 295 299 320
P7 | Username | Bank | Bet | Cards |
Bet (size same as State)
1 B: Bet (Opcode)
4 B: Response Arguments (amount of bet)
2 B: Seq. # + 1
All other fields are a copy of the last received “State” above
Server Response:
None
Stand (size same as State)
1 B: Stand (Opcode)
4 B: Response Arguments (0 for “Stand”)
2 B: Seq. # + 1
All other fields are a copy of the last received “State” above
Server Response:
None
Hit (size same as State)
1 B: Hit (Opcode)
4 B: Response Arguments (0 for “Hit”)
2 B: Seq. # + 1
All other fields are a copy of the last received “State” above
Server Response:
None
Quit (size same as State)
1 B: Quit (Opcode) // free seat in state
4 B: Response Arguments (0000)
2 B: Seq. # + 1
All other fields are a copy of the last received “State” above
Server Response:
None
Error (size 142B)
1 B: Error (Opcode)
1 B: Error Code:
General error (0)
No money (1)
No room/seats full (2)
Name already taken/active (3)
Invalid name (4)
Timeout error (5)
140 B: Description (NUL-terminated human readable ASCII string; optional)
Message (size 165B)
1 B: Message (Opcode)
4 B: Client seq num
4 B: Server seq num (order in which the message goes into the list)
0 if the client is sending the message
Populated by the server on broadcast
12 B: Player
144 B: message (must be null terminated) (143 chars)
Message ack (size 5B)
1 B: ACK (Opcode)
4 B: Server seq num
The messages are acked only when received by the server, the client retries until they receive their message back.
Sequence numbers are unsigned 4 byte in messages and acks, everywhere else they are 2 bytes.
Opcodes
Status update (0)
Connect request (1)
Bet (2)
Stand (3)
Hit (4)
Quit (5)
Error (6)
Message (7)
Ack (8)
Every packet is a fixed sized (even packets including variable length strings, anything after the nul terminator is zeroed out)
Card Values (in chars/bytes)
| Value | Encoded (1 byte) |
|---|---|
| None / Facedown | 0 |
| AH (ace of hearts) | 1 |
| 2H | 2 |
| 3H | 3 |
| ... | ... |
| AD | 14 |
| ... | ... |
| AS | 27 |
| ... | ... |
| AC | 40 |
| ... | ... |
| KC (king of clubs) | 52 |