6. Detailed server packet analysis

6. Detailed server packet analysis
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This section goes through the individual packets that the server can send.

6.1. The ERROR_MESSAGE packet

The error message packet is sent back to the client to inform the client that an error has occurred.

Table 11. ERROR_MESSAGE contents

Length	Content (if fixed)	Name	Description
2 bytes	00 02	MARK_ERROR	A marker to indicate that this block contains an error string.
4 bytes	xx xx xx xx	ERROR_LEN	The length of the error string.
variable		ERROR_STRING	The error string.
2 bytes	00 01	MARK_UNKNOWN	Unknown.
4 bytes	00 00 00 02	UNKNOWN_LEN	Unknown
2 bytes	00 01	UNKNOWN	Unknown.

6.2. The LOGIN_NOTIFY packet

Table 12. LOGIN_NOTIFY contents

Length	Content (if fixed)	Name	Description
2 bytes	00 02	X1	Unknown marker.
4 bytes	xx xx xx xx	TEXT_LEN1	The length of the notification string.
variable		NOTICE_STRING	The notification string

6.3. The LOGIN_BAD_RESP packet

Table 13. LOGIN_BAD_RESP contents

Length	Content (if fixed)	Name	Description
2 bytes	00 02	X1	Unknown.
4 bytes	xx xx xx xx	TEXT_LEN1	The length of the error string.
variable		ERROR_STRING	A string indicating the error.
2 bytes	00 01	X2	Unknown.
4 bytes	00 00 00 02	X3	Unknown.
2 bytes	00 01	X4	Unknown.

6.4. The REGISTER_OK packet

Registration successful message when client sends a proper REGISTER packet.

Table 14. REGISTER_OK contents

Length	Content (if fixed)	Name	Description
2 bytes	00 01	X1	Unknown. Possibly a marker for the welcome message.
4 bytes	xx xx xx xx	WELCOMEMSG_LEN	The length of the welcome message
variable		WELCOMEMSG	The welcome message

6.5. The KEEP_ALIVE_RESP packet

The KEEP_ALIVE_RESP packet is sent from the server to the client after the server receives a KEEP_ALIVE packet. This packet contains no data. A sequence number is stored in the low command bytes. It seems to always match the sequence number from the last KEEP_ALIVE packet.

6.6. The LOGIN_CHAL packet

The login challenge packet.

Table 15. LOGIN_CHAL contents

Length	Content (if fixed)	Name	Description
2 bytes	00 02	X1	Unknown.
4 bytes	xx xx xx xx	TEXT_LEN1	The length of an unknown string.
variable		X2	An unknown random string.
2 bytes	00 01	X1	Unknown.
4 bytes	xx xx xx xx	TEXT_LEN2	The length of the hashing string.
variable		HASH_STRING	The bytes of the hashing string.

The HASH_STRING is used in the LOGIN_RESP packet sent by the client to generate a proper hash code.

6.7. The LOGIN_OK / MOTD packet

The login OK message with optional message of the day.

Table 16. LOGIN_OK / MOTD contents

Length	Content (if fixed)	Name	Description
2 bytes	00 0C	BLOCK_EXCHANGE_RATE	Used to mark the exchange rate block. Not in all responses.
4 bytes	xx xx xx xx	EXCHANGE_RATE_LEN	The length of the exchange rate message
variable		EXCHANGE_RATE	The exchange rate message
2 bytes	00 0B	X2	Unknown.
4 bytes	xx xx xx xx	CURRENCY_LEN	Length of the currency field
variable		CURRENCY	The currency. "USD" for US dollars.
2 bytes	00 0A	X3	Unknown.
4 bytes	xx xx xx xx	UNKNOWN_IP_LEN	An IPv4 address
variable		IP_ADDRESS	An ip address. (e.g. "202.154.106.233")
2 bytes	00 09	X4	Unknown.
4 bytes	00 00 00 04	X5	Unknown.
4 bytes	00 00 00 03	X6	Unknown.
2 bytes	00 08	X7	Unknown.
4 bytes	00 00 00 01	X8	Unknown.
1 byte	00	X9	Unknown.
2 bytes	00 06	X10	Unknown.
4 bytes	00 00 00 01	X11	Unknown.
1 byte	00	X12	Unknown.
2 bytes	00 03	X13	Unknown.
4 bytes	xx xx xx xx	MOTD_LEN	Length of the MOTD string
variable		MOTD	The message of the day
2 bytes	00 02	X14	Unknown.
4 bytes	00 00 00 01	X15	Unknown.
2 bytes	00	X16	Unknown.
1 byte	00 01	X17	Unknown.
4 bytes	xx xx xx xx	MOBILE_NUM_LEN	The length of the string containing your mobile number
variable		MOBILE_NUM	Your mobile number including country code without () or dashes

6.8. The CLIST_GROUPS packet

The packet sent after the client requests the contact list. This packet contains the groups on the contact list. Each group is sent in a different packet.

Table 17. CLIST_GROUPS contents

Length	Content (if fixed)	Name	Description
2 bytes	00 02	MARK_GROUPNAME	A marker that indicates this block contains the name of the group.
4 bytes	xx xx xx xx	GROUPNAME_LEN	The length of the name of the group
variable		GROUPNAME	The name of the group. (e.g. "mig33 Contacts")
2 bytes	00 01	MARK_ID	A marker for an unknown block.
4 bytes	00 00 00 04	ID_LEN	Seems to always be 4.
4 bytes	xx xx xx xx	ID	An ID number for this group.

The ID number is used when you get the buddies in the contact list. In block 4 of the contact packet, the ID code will tell you which group a buddy belongs to.

6.9. The CLIST_BUDDIES packet

The packet sent after the client requests the contact list. This packet contains the buddies on the contact list. Each buddy is sent in a different packet.

Table 18. CLIST_BUDDIES contents

Length	Content (if fixed)	Name	Description
2 bytes	00 19	MARK_UNKNOWN	A marker for an unknown block.
4 bytes	00 00 00 01	UNKNOWN_LEN	The length for some unknown data. Possibly a flag.
1 byte	00	UNKNOWN	An unknown piece of data. Seems to always be 0?
2 bytes	00 03	MARK_USERNAME	A marker for the username
4 bytes	xx xx xx xx	USERNAME_LEN	The length of the username
variable		USERNAME	The username.
2 bytes	00 0D	MARK_STATUS	A marker used to indicate a buddy's status.
4 bytes	00 00 00 01	STATUS_LEN	The length of the status byte.
1 byte	xx	STATUS	Status. 0x63 = "Offline", 0x01 = "Online".
2 bytes	00 02	MARK_GROUP_ID	A marker used to indicate which group a buddy is in.
4 bytes	00 00 00 04	GROUP_ID_LEN	The length of the GROUP_ID.
4 bytes	xx xx xx xx	GROUP_ID	The group ID that this buddy belongs to.
2 bytes	00 0C	MARK_BUDDY_NAME	A marker used ot indicate the buddies name again.
4 bytes	xx xx xx xx	BUDDY_NAME_LEN	The length of the buddies name.
variable		BUDDY_NAME	The buddy's name.
2 bytes	00 01	MARK_BUDDY_ID	A marker for the buddy ID.
4 bytes	00 00 00 04	BUDDY_ID_LEN	The length of the buddy ID.
4 bytes	xx xx xx xx	BUDDY_ID	The Buddy ID.

6.10. The CLIST_TERMINATOR packet

The contact list terminator. It has no parameters.

6.11. The CLIST_STATUS_CHANGE packet

The packet sent to notify a client that a buddy's status has changed.

Table 19. CLIST_STATUS_CHANGE contents

Length	Content (if fixed)	Name	Description
2 bytes	00 02	MARK_STATUS	A marker that indicates this block contains the status number.
4 bytes	00 00 00 01	STATUS_LEN	The length of the status byte.
1 byte	xx	STATUS	The users status. 0x63 = Offline, 0x01 = Online.
2 bytes	00 01	MARK_BUDDY_ID	A marker to indicate the buddy id.
4 bytes	00 00 00 04	BUDDY_ID_LEN	The length of the buddy ID.
4 bytes	xx xx xx xx	BUDDY_ID	The buddy id who's status has changed.

6.12. The RECV_MSG packet

The packet sent to notify a client that another user sent a message to a chat room or mig33 contact.

Table 20. RECV_MSG contents

Length	Content (if fixed)	Name	Description
2 bytes	00 08	MARK_MSG	A marker that indicates this block is the chat message.
4 bytes	xx xx xx xx	MSG_LEN	Length of the chat message.
variable		MSG	The bytes that make up the chat message.
2 bytes	00 06	MARK_X1	A marker for an unknown block.
4 bytes	00 00 00 02	X2_LEN	An unknown length
2 bytes	00 01	X3	An unknown piece of data.
2 bytes	00 04	MARK_DESTINATION	A marker for the destination string.
4 bytes	xx xx xx xx	DESTINATION_LEN	Length of the string containing the destination.
variable		DESTINATION	The name of the destination. Can be either a chatroom or a user's name.
2 bytes	00 03	MARK_X4	A marker for an unknown block.
4 bytes	00 00 00 01	X5_LEN	An unknown length
1 byte	xx	X6	Unknown. Can be 03 or 01. This may be an indication of whether the message is to a chat room or to a user.
2 bytes	00 02	MARK_USER	A marker for the user who sent the message.
4 bytes	xx xx xx xx	USER_LEN	The lenght of the username
variable		USER	The username that sent the message.
2 bytes	00 01	MARK_X7	An unknown marker.
4 bytes	00 00 00 01	X8_LEN	An unknown length
1 byte	01	X9	Unknown.

6.13. The RECV_SYS_MSG packet

This packet is sent to the client when the server needs to inform the client about some event.

Table 21. RECV_SYS_MSG contents

Length	Content (if fixed)	Name	Description
2 bytes	00 05	MARK_DATA	A marker that indicates this block contains the data of the system message.
4 bytes	xx xx xx xx	DATA_LEN	Length of the data message.
variable		DATA	The bytes that make up the data. Could be a URL.
2 bytes	00 04	MARK_DESC	A marker that indicates this block contains a description of the data in the system mesage.
4 bytes	xx xx xx xx	DESC_LEN	Length of the description.
variable		DESC	The bytes that make up the decription.
2 bytes	00 02	MARK_INVOKER	A marker that indicates this block contains the invoker of the system message.
4 bytes	xx xx xx xx	INVOKER_LEN	Length of the invoker's nick.
variable		INVOKER	The bytes that make up the invoker's name
2 bytes	00 01	MARK_UNKNOWN	An unknown block of data.
4 bytes	00 00 00 01	UNKNOWN_LEN	An unknown length. Seems to always be 1 byte.
1 byte	01	Unknown	Seems to always be 01.