| Author | Message | Time |
|---|---|---|
| Ringo | As a few of you may know i was stuck with sending data via a UDP winsock, since then iv had a brake and came back to it, but i am having problems understanding the format of "00 00 00 00" SC UDP packets. Here are some logs to show what i am on about: [code] 1 192.168.0.135:4225 63.240.202.138:6112 96 Send 0000 FF 1C 60 00 00 00 00 00 00 00 00 00 02 00 01 00 ..`............. 0010 1F 00 00 00 00 00 00 00 31 76 31 20 4F 6E 20 43 ........1v1 On C 0020 68 61 6C 6C 65 6E 67 65 72 00 00 2C 33 34 2C 31 hallenger..,34,1 0030 32 2C 36 2C 31 2C 32 2C 2C 31 2C 64 34 31 66 38 2,6,1,2,,1,d41f8 0040 36 64 36 2C 2C 2C 54 48 49 53 69 73 4D 59 61 63 6d6,,,THISisMYac 0050 63 49 44 0D 43 68 61 6C 6C 65 6E 67 65 72 0D 00 cID.Challenger.. 2 63.240.202.138:6112 192.168.0.135:4225 8 Recv 0000 FF 1C 08 00 00 00 00 00 ........ 3 192.168.0.135:4225 63.240.202.138:6112 4 Send 0000 FF 10 04 00 .... [/code] Telling the server the SC client has created a game [code] 4 :0 192.168.0.135:6112 8 RecvFrom 0000 03 00 00 00 00 00 00 00 ........ 5 192.168.0.135:6112 :0 8 SendTo 0000 03 00 00 00 01 00 00 00 ........[/code] SC (in this case) Recv/Sent this UDP packet 80 more times untill somone joined the game. This must be some kinda ping packet or somthing. [code] 172 :0 192.168.0.135:6112 8 RecvFrom 0000 03 00 00 00 00 00 00 00 ........ 173 192.168.0.135:6112 :0 8 SendTo 0000 03 00 00 00 01 00 00 00 ........ 174 :0 192.168.0.135:6112 20 RecvFrom 0000 00 00 00 00 28 C4 10 00 00 00 01 00 00 01 FF 00 ....(........... 0010 01 00 00 00 .... 175 :0 192.168.0.135:6112 20 RecvFrom 0000 00 00 00 00 28 C4 10 00 00 00 01 00 00 01 FF 00 ....(........... 0010 01 00 00 00 .... 176 :0 192.168.0.135:6112 20 RecvFrom 0000 00 00 00 00 28 C4 10 00 00 00 01 00 00 01 FF 00 ....(........... 0010 01 00 00 00 .... [/code] These 3 Null UDP packets are sent to the SC client when another SC client try's to join the game. You may have already noticed that the 7th and 8th byte Word is the packet lengh (Not including the 1st Null DWord) [code] 177 192.168.0.135:6112 :0 20 SendTo 0000 00 00 00 00 33 B7 10 00 01 00 01 00 00 02 00 00 ....3........... 0010 01 00 00 00 .... [/code] So SC responds with this [code] 178 :0 192.168.0.135:6112 20 RecvFrom 0000 00 00 00 00 40 A8 10 00 01 00 02 00 00 03 FF 00 ....@........... 0010 01 00 00 00 .... 179 :0 192.168.0.135:6112 59 RecvFrom 0000 00 00 00 00 01 39 37 00 02 00 02 00 00 07 FF 00 .....97......... 0010 52 65 6D 69 74 6F 75 72 69 6E 69 29 45 28 00 52 Remitourini)E(.R 0020 41 54 53 20 30 20 30 20 32 36 20 30 20 30 20 30 ATS 0 0 26 0 0 0 0030 20 30 20 30 20 52 41 54 53 00 00 0 0 RATS.. [/code] But now it gets interesting because the 2nd packet recv here with the players username, client and stats string varys. The 5th and 6th byte Word varys every time a player trys to join and SC recv's this packet. [code] 180 192.168.0.135:4225 63.240.202.138:6112 96 Send 0000 FF 1C 60 00 06 00 00 00 30 00 00 00 02 00 01 00 ..`.....0....... 0010 1F 00 00 00 00 00 00 00 31 76 31 20 4F 6E 20 43 ........1v1 On C 0020 68 61 6C 6C 65 6E 67 65 72 00 00 2C 33 34 2C 31 hallenger..,34,1 0030 32 2C 36 2C 31 2C 32 2C 2C 31 2C 64 34 31 66 38 2,6,1,2,,1,d41f8 0040 36 64 36 2C 2C 2C 54 48 49 53 69 73 4D 59 61 63 6d6,,,THISisMYac 0050 63 49 44 0D 43 68 61 6C 6C 65 6E 67 65 72 0D 00 cID.Challenger.. [/code] SC Notifys the server that the game state is now full. [code] 181 192.168.0.135:6112 :0 108 SendTo 0000 00 00 00 00 57 3A 68 00 02 00 03 00 00 08 00 00 ....W:h......... 0010 01 00 00 00 02 00 00 00 B5 00 00 00 06 00 00 00 ................ 0020 30 00 00 00 31 76 31 20 4F 6E 20 43 68 61 6C 6C 0...1v1 On Chall 0030 65 6E 67 65 72 00 2C 33 34 2C 31 32 2C 36 2C 31 enger.,34,12,6,1 0040 2C 32 2C 2C 31 2C 64 34 31 66 38 36 64 36 2C 2C ,2,,1,d41f86d6,, 0050 2C 54 48 49 53 69 73 4D 59 61 63 63 49 44 0D 43 ,THISisMYaccID.C 0060 68 61 6C 6C 65 6E 67 65 72 0D 00 00 hallenger... [/code] Now SC sends the player the game info with added Words and DWords. Also the 5th and 6th byte Word that SC sends also varys. [code] 182 192.168.0.135:6112 :0 67 SendTo 0000 00 00 00 00 BC 9B 3F 00 03 00 03 00 00 06 00 00 ......?......... 0010 33 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 3............... 0020 B5 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0030 00 00 00 00 54 48 49 53 69 73 4D 59 61 63 63 49 ....THISisMYaccI 0040 44 00 00 D.. [/code] Now SC sends the player lots more Dwords and my account name. [code] 183 192.168.0.135:6112 :0 20 SendTo 0000 00 00 00 00 A3 36 10 00 04 00 03 00 00 0F 00 00 .....6.......... 0010 00 00 00 00 .... 184 192.168.0.135:6112 :0 48 SendTo 0000 00 00 00 00 78 09 2C 00 05 00 03 00 00 09 00 00 ....x.,......... 0010 02 00 01 00 00 00 00 00 01 01 01 02 02 00 03 01 ................ 0020 00 01 00 00 00 00 00 32 00 00 00 00 00 00 00 00 .......2........ 185 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 F9 88 0D 00 B3 00 B5 00 02 00 00 00 ................ 0010 05 . 186 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 FC 84 0D 00 B4 00 B5 00 02 00 00 00 ................ 0010 05 . 187 192.168.0.135:6112 :0 16 SendTo 0000 00 00 00 00 4D 99 0C 00 06 00 03 00 00 04 00 00 ....M........... 188 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 FF 80 0D 00 B5 00 B5 00 02 00 00 00 ................ 0010 05 . [/code] Then SC sends the player all that... [code] 191 :0 192.168.0.135:6112 16 RecvFrom 0000 00 00 00 00 69 7A 0C 00 03 00 07 00 00 05 01 00 ....iz.......... 192 :0 192.168.0.135:6112 16 RecvFrom 0000 00 00 00 00 64 7F 0C 00 04 00 07 00 00 04 01 00 ....d........... [/code] Then the player sends SC this.. [code] 193 192.168.0.135:6112 :0 16 SendTo 0000 00 00 00 00 62 80 0C 00 07 00 05 00 00 05 00 00 ....b........... [/code] So SC sends this.. [code] 194 63.240.202.138:6112 192.168.0.135:4225 8 Recv 0000 FF 1C 08 00 00 00 00 00 ........ [/code] Finaly the chat server replys for the change of game state (when the player joined) [code] 195 :0 192.168.0.135:6112 8 RecvFrom 0000 03 00 00 00 00 00 00 00 ........ 196 192.168.0.135:6112 :0 8 SendTo 0000 03 00 00 00 01 00 00 00 ........ [/code] The SC gets/sends this just for fun! [code] 197 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 03 7C 0D 00 B6 00 B5 00 02 00 00 00 .....|.......... 0010 05 . 198 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 13 6A 0D 00 B5 00 B7 00 02 00 01 00 .....j.......... 0010 05 . 199 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 16 66 0D 00 B6 00 B7 00 02 00 01 00 .....f.......... 0010 05 . 200 :0 192.168.0.135:6112 16 RecvFrom 0000 00 00 00 00 5F 82 0C 00 08 00 08 00 00 00 01 01 ...._........... 201 192.168.0.135:6112 :0 79 SendTo 0000 00 00 00 00 1C 3D 4B 00 00 00 00 00 01 00 00 00 .....=K......... 0010 4A 00 00 60 00 80 00 06 06 00 00 00 00 00 00 00 J..`............ 0020 00 00 00 06 06 02 01 00 02 01 00 00 00 00 00 06 ................ 0030 06 00 00 00 00 00 00 00 00 00 00 01 01 00 00 00 ................ 0040 00 00 00 01 00 00 00 01 01 00 00 00 00 00 00 ............... 202 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 8A 16 0D 00 01 00 00 00 01 00 00 00 ................ 0010 50 P 203 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 10 6C 0D 00 B7 00 B7 00 02 00 00 00 .....l.......... 0010 05 . 204 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 1E 5C 0D 00 B7 00 B8 00 02 00 01 00 .....\.......... 0010 05 . 205 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 18 62 0D 00 B8 00 B8 00 02 00 00 00 .....b.......... 0010 05 . 206 :0 192.168.0.135:6112 16 RecvFrom 0000 00 00 00 00 36 B6 0C 00 02 00 02 00 01 00 01 01 ....6........... 207 :0 192.168.0.135:6112 34 RecvFrom 0000 00 00 00 00 C1 8A 1E 00 B8 00 B9 00 02 00 01 00 ................ 0010 40 00 00 00 00 00 00 00 00 01 00 05 00 00 6A D5 @.............j. 0020 6C 2D l- 208 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 20 58 0D 00 B9 00 B9 00 02 00 00 00 .... X.......... 0010 05 . 209 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 2E 48 0D 00 B9 00 BA 00 02 00 01 00 .....H.......... 0010 05 . [/code] Then after all that.. [code] 210 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 28 4E 0D 00 BA 00 BA 00 02 00 00 00 ....(N.......... 0010 05 . 211 192.168.0.135:6112 :0 21 SendTo 0000 00 00 00 00 50 51 11 00 02 00 00 00 01 00 00 00 ....PQ.......... 0010 49 01 00 00 00 I.... 212 192.168.0.135:6112 :0 47 SendTo 0000 00 00 00 00 B8 59 2B 00 03 00 00 00 01 00 00 00 .....Y+......... 0010 4F 1C 00 01 00 01 D8 00 00 43 F5 47 09 28 32 29 O........C.G.(2) 0020 43 68 61 6C 6C 65 6E 67 65 72 2E 73 63 6D 00 Challenger.scm. 213 192.168.0.135:4225 63.240.202.138:6112 26 Send 0000 FF 0E 1A 00 2F 61 73 74 61 74 20 52 65 6D 69 74 ..../astat Remit 0010 6F 75 72 69 6E 69 29 45 28 00 ourini)E(. [/code] Now it seems all the checks or what ever are done and the client can join fully and become visible to my SC client in the game room. (as my SC has sent him the map for when the game starts and for him to check he/she has it) [code] 214 :0 192.168.0.135:6112 27 RecvFrom 0000 00 00 00 00 3F 71 17 00 00 00 04 00 01 00 01 00 ....?q.......... 0010 4F 08 00 00 00 00 01 01 D8 00 00 O.......... 215 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 36 3E 0D 00 BA 00 BB 00 02 00 01 00 ....6>.......... 0010 05 . [/code] Then the player sends SC that. [code] 219 192.168.0.135:6112 :0 82 SendTo 0000 00 00 00 00 C8 1D 4E 00 BB 00 BB 00 02 00 00 00 ......N......... 0010 3D 64 3E 07 FF 00 00 00 3E 06 FF 00 01 00 3E 05 =d>.....>.....>. 0020 FF 00 02 00 3E 04 FF 00 00 00 3E 03 FF 00 01 00 ....>.....>..... 0030 3E 02 FF 00 02 00 3E 01 01 02 06 00 3E 00 00 02 >.....>.....>... 0040 06 00 3F 01 00 00 01 00 05 00 3F 00 00 00 01 00 ..?.......?..... 0050 05 00 .. [/code] Now im guessing this packet or the large chunky packet before this (like this one) is alot of Word values for the ingame room state, like open/closed slots and my selected race, things like that? [code] 220 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 3E 34 0D 00 BB 00 BC 00 02 00 01 00 ....>4.......... 0010 05 . 221 192.168.0.135:6112 :0 16 SendTo 0000 00 00 00 00 25 CA 0C 00 01 00 01 00 01 00 00 01 ....%........... 222 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 38 3A 0D 00 BC 00 BC 00 02 00 00 00 ....8:.......... 0010 05 . 223 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 46 2A 0D 00 BC 00 BD 00 02 00 01 00 ....F*.......... 0010 05 . 224 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 40 30 0D 00 BD 00 BD 00 02 00 00 00 ....@0.......... 0010 05 . 225 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 4E 20 0D 00 BD 00 BE 00 02 00 01 00 ....N .......... 0010 05 . 226 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 48 26 0D 00 BE 00 BE 00 02 00 00 00 ....H&.......... 0010 05 . 227 :0 192.168.0.135:6112 18 RecvFrom 0000 00 00 00 00 76 58 0E 00 BE 00 BF 00 02 00 01 00 ....vX.......... 0010 3D 64 =d 228 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 50 1C 0D 00 BF 00 BF 00 02 00 00 00 ....P........... 0010 05 . 229 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 5E 0C 0D 00 BF 00 C0 00 02 00 01 00 ....^........... 0010 05 . 230 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 58 12 0D 00 C0 00 C0 00 02 00 00 00 ....X........... 0010 05 . [/code] And some more... [code] 231 :0 192.168.0.135:6112 21 RecvFrom 0000 00 00 00 00 2F 25 11 00 01 00 04 00 01 00 01 00 ..../%.......... 0010 4C 68 65 79 00 Lhey. 232 :0 192.168.0.135:6112 17 RecvFrom 0000 00 00 00 00 66 02 0D 00 C0 00 C1 00 02 00 01 00 ....f........... 0010 05 . 233 192.168.0.135:6112 :0 17 SendTo 0000 00 00 00 00 60 08 0D 00 C1 00 C1 00 02 00 00 00 ....`........... 0010 05 . 234 192.168.0.135:6112 :0 16 SendTo 0000 00 00 00 00 2D C0 0C 00 02 00 02 00 01 00 00 01 ....-........... 235 192.168.0.135:6112 :0 107 SendTo 0000 00 00 00 00 1C B1 67 00 04 00 02 00 01 00 00 00 ......g......... 0010 4C 68 69 68 69 68 68 69 68 69 68 69 68 69 68 69 Lhihihhihihihihi 0020 68 69 68 69 68 69 68 69 68 69 68 68 69 68 69 68 hihihihihihhihih 0030 69 68 69 68 69 68 69 68 69 68 69 68 69 68 69 68 ihihihihihihihih 0040 69 68 69 68 69 68 69 68 68 69 68 69 68 69 68 69 ihihihihhihihihi 0050 68 69 68 69 68 69 68 69 68 69 68 69 68 69 68 69 hihihihihihihihi 0060 68 69 68 69 68 69 68 69 68 69 00 hihihihihi. [/code] Him saying "hay" And me happy to see him :) (lots of hi's) In a number of them send/recv packets the 5th and 6th Word varys and im not sure why or what makes it. And also if client to client packets are Null DWord then there must be a 2nd packet ID or somthing in the packet. So far iv been useing the 13th to 16th byte DWord as a referance to guild me. If anyone can inlighten me a little on the format of the null dword sc UDP packet i would be most greatfull!! thanks in advance! Ringo | December 31, 2004, 2:00 AM |
| R.a.B.B.i.T | They appear to be just SID_NULLS (or rather the UDP variant of it). You may want to log several games and compare values to see if you can figure out what's what. Also, 213 is a normal Battle.Net BNCS TCP packet not UDP. | December 31, 2004, 4:09 AM |
| Ringo | [quote author=R.a.B.B.i.T link=topic=10059.msg93917#msg93917 date=1104466153] They appear to be just SID_NULLS (or rather the UDP variant of it). You may want to log several games and compare values to see if you can figure out what's what. Also, 213 is a normal Battle.Net BNCS TCP packet not UDP. [/quote] I left the 213 chat packet in to show its when the client shows in the game room and you view there stats. But when SC gets these packets, the 1st DWord i would say is somthing like a packet ID but more like a packet class, null being client game interaction? The fact that the lengh of the packet is with in the packet its self and it blatently doesnt count the 1st null Dword, would say to me that SC reads them from the 5th byte on. Also i now think the 9th and 10th byte Word is the packet ID. This would make it somthing like: Word ? Word packet lengh Word Packet ID (void) data or possibly somthing like this: Word ? Word packet lengh Word Packet ID Word ? Word ? Word ? (void) data ? = 1 of the things im trying to figger out. Or maybe the Word Packet ID is infact a packet ID byte followed by a null byte? Iv also done many logs of exacly the same style games, hence saying the 1st word (after the null Dword) can vary both ways and couldnt find many clues. but i really need some help veryifying this. Ringo | December 31, 2004, 5:06 AM |
| UserLoser. | Nice work. Good to see someone do something their selves these days. The first WORD after the first DWORD is a checksum result performed on the packet's data. The other few unknowns I'm not quite sure of, though, but I think some should be treated as 8-bit (BYTE) values. I do know one of them is your player id. Search forum, adron or iago or someone posted an explanation not too long ago | December 31, 2004, 5:46 AM |
| Ringo | [quote author=UserLoser link=topic=10059.msg93931#msg93931 date=1104472009] The first WORD after the first DWORD is a checksum result performed on the packet's data. [/quote] Thanks for the fast reply UserLoser! Ah ha, a check sum of the data would make sence as to why there were no visible clues as to how they were generated! **Edit** i was unable to find the post, but what offsets/bytes would be used to create a check sum of the packet? (If not all) and what other things would i need to know if i were to write a function for this? Thanks again in advance. HAPPY NEW YEAR EVERYONE!! Ringo | December 31, 2004, 6:24 AM |
| R.a.B.B.i.T | I noticed a few spots where the 3rd DWORD increments its second byte, but only for a few packets in a row, before it changes. Note 181-184, then 185 changes and begins a new increment series, but 187 jumps back to the 181-184 series. It looks like an identifier to which stream the packet is coming from, and is a counter as well as a checksum. I don't have any values right now for the checksum, but I'll see if I can figure something out. | January 1, 2005, 6:02 PM |
| R.a.B.B.i.T | I'm working on that now (thanks for distracting me, I needed it!). My question is what are the VB6 equivs of >> and <<? Also, these don't work for values < 100. | January 2, 2005, 6:15 PM |
| Arta | I don't think there are any in VB6. You'll need to write (or find) equivalent functions. | January 2, 2005, 6:21 PM |
| R.a.B.B.i.T | Hmm. Well then could you explain how they operate in C++? All I know is that they are overloaders, but not much else. | January 2, 2005, 6:24 PM |
| UserLoser. | [quote author=R.a.B.B.i.T link=topic=10059.msg94133#msg94133 date=1104690246] Hmm. Well then could you explain how they operate in C++? All I know is that they are overloaders, but not much else. [/quote] They shift a value X number of bits either to the right or left. This could be done in VB (or any language) with some simple math | January 2, 2005, 6:47 PM |
| R.a.B.B.i.T | Thank you. Now for clarity: they shift the number x bits as in ring-counter style, or filler-style, and if filler, 0 or 1? | January 2, 2005, 8:03 PM |
| tA-Kane | [quote author=R.a.B.B.i.T link=topic=10059.msg94141#msg94141 date=1104696182] Thank you. Now for clarity: they shift the number x bits as in ring-counter style, or filler-style, and if filler, 0 or 1? [/quote] Remember, it's bit shift, not bit rotate 0x0000000F << 4 == 0x000000F0 0xF0000000 >> 4 == 0x0F000000 Easy enough. | January 3, 2005, 8:02 PM |
| R.a.B.B.i.T | Ho-hum! Thanks. I think I should be able to make this work in VB now :) | January 3, 2005, 10:57 PM |
| R.a.B.B.i.T | *bump* Okay, with the help of PiaNKa, UDPChecksum() in VB6 works :) [code]Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _ (ByRef Destination As Any, ByRef Source As Any, ByVal numBytes As Long) Private Function UDPCheckSum(bufa As String) As Long Dim subsum As Long Dim a As Long Dim b As Long Dim c As Long Dim lnt As Integer CopyMemory lnt, ByVal Mid$(bufa, 3, 2), 2 lnt = lnt - 2 subsum = SubChecksum(Mid(bufa, 3), lnt) a = &HFF - ((subsum And &HFF) + (ShiftRight(subsum, 8))) Mod &HFF b = ((&HFF - (a + (ShiftRight(subsum, 8))) Mod &HFF) And &HFF) Or ShiftLeft(a, 8) CopyMemory c, b, 2 UDPCheckSum = c + 1 End Function Private Function SubChecksum(ByRef buf As String, length As Integer) As Long Dim sum1 As Double Dim sum2 As Double Dim p As Long sum1 = sum2 = 0 For p = length To 1 Step -1 If Len(CStr(buf)) < p Then Exit For sum2 = sum2 + Asc(Mid$(buf, p, 1)) If sum2 > &HFF Then sum2 = sum2 - &HFF sum1 = sum1 + sum2 Next p SubChecksum = ShiftLeft((sum2 And &HFF), 8) Or ((sum1 Mod &HFF) And &HFF) End Function Public Function ShiftRight(ByVal a As Long, ByVal L As Long) As Long ShiftRight = CLng(a / (2 ^ L)) End Function Public Function ShiftLeft(ByVal a As Long, ByVal L As Long) As Long ShiftLeft = CLng(a * (2 ^ L)) End Function[/code] | January 9, 2005, 8:01 PM |
| PiaNKA | *sigh*, your code is...yeah...here... ...lol [code] Private Function RShift(ByVal pnValue As Long, ByVal pnShift As Long) As Double On Error Resume Next RShift = CDbl(pnValue \ (2 ^ pnShift)) End Function Private Function LShift(ByVal pnValue As Long, ByVal pnShift As Long) As Double On Error Resume Next LShift = CDbl(pnValue * (2 ^ pnShift)) End Function Private Function SubCheckSum(ByVal buf As String, ByVal length As Integer) As Long Dim sum1, sum2 Dim i As Integer, iY As Integer For iY = 0 To length - 1 i = length - iY sum2 = sum2 + Asc(Mid(buf, i, 1)) If sum2 > &HFF Then sum2 = sum2 - &HFF End If sum1 = sum1 + sum2 Next iY SubCheckSum = (LShift((sum2 And &HFF), 8)) Or ((sum1 Mod &HFF) And &HFF) End Function Private Function UDPCheckSum(buf As String) As Integer Dim subsum As Long, length As Integer Dim a As Long, b As Long, Ret As Integer CopyMemory length, ByVal Mid$(buf, 3, 2), 2 length = length - 2 subsum = SubCheckSum(Mid$(buf, 3), length) a = &HFF - ((subsum And &HFF) + (RShift(subsum, 8))) Mod &HFF b = CLng((((&HFF - (a + RShift(subsum, 8)) Mod &HFF) And &HFF) Or LShift(a, 8))) CopyMemory Ret, b, 2 UDPCheckSum = Ret End Function Public Sub SendUDPPacket(ByVal Sock As Winsock, ByVal bytPacketID As Byte) Dim Checksum As Integer If bytPacketID = &H3 Then Sock.SendData MakeDWORD(CLng(&H3)) & strBuffer Clear Else Checksum = UDPCheckSum(MakeWORD(0) & MakeWORD(Len(strBuffer)) & strBuffer) Sock.SendData MakeDWORD(0) & MakeWORD(Checksum) & MakeWORD(Len(strBuffer)) & _ strBuffer Clear End If End Sub [/code] Note that the SendUDPPacket has not been tested, although it exemplifies the correct usage of the UDPCheckSum() function...enjoy | January 9, 2005, 8:07 PM |