SNAC(04,06)/CH4 client send channel4 message command

SNAC(04,06)/CH4

CLI_SEND_ICBM_CH4

ICQ clients use this snac to send messages to an old/offline/invisible clients if message type != 1 or message flags != 0 (for example plain-text multi-recipient message to an offline client) but this doesn't mean that you can't send usual plain-text message on channel 4. TLV(0x03) and TLV(0x06) is optional.

00 04	word	SNAC family
00 06	word	SNAC subtype
00 00	word	SNAC flags
xx xx xx xx	dword	SNAC request-id

xx xx xx xx xx xx xx xx	qword	msg-id cookie
00 04	word	message channel
xx	byte	screenname string length
xx ..	string	screenname string

00 05		word		TLV.Type(0x05) - message data
xx xx		word		TLV.Length

xx xx xx xx	dword (LE)	Sender uin
xx	byte	Message type
xx	byte	Message flags
xx xx	word (LE)	Message string length
xx .. 00	string (asciiz)	Message string

00 03		word		TLV.Type(0x03) - request an ack from server
00 00		word		TLV.Length

empty

00 06		word		TLV.Type(0x06) - store message if recipient offline
00 00		word		TLV.Length

empty

Example SNAC dumps with flap header:


  2a 02 56 1e 00 6f 00 04-00 06 00 00 00 0b 00 06   *.V..o..........
  4e b5 6c 01 33 28 00 00-00 04 07 31 30 30 30 30   N.l.3(.....10000
  30 30 00 05 00 4b 8f e4-5e 00 04 00 43 00 54 68   00...K..^...C.Th
  69 73 20 69 73 20 74 68-65 20 74 65 73 74 20 75   is is the test u
  72 6c 20 6d 65 73 73 61-67 65 20 74 6f 20 61 6e   rl message to an
  20 6f 6c 64 20 63 6c 69-65 6e 74 fe 68 74 74 70    old client.http
  3a 2f 2f 68 74 74 70 2e-74 65 73 74 2e 75 72 6c   ://http.test.url
  00 00 06 00 00                                    .....