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| | | |
| UDS [[NWMUDS:Bind|data_channel]] 0x1 is used for spectator data, while all non-spectator data uses data_channel 0x2. The spectator data is received by connecting to the network as a spectator then receiving data-frames, this is handled when scanning for DLP networks. | | UDS [[NWMUDS:Bind|data_channel]] 0x1 is used for spectator data, while all non-spectator data uses data_channel 0x2. The spectator data is received by connecting to the network as a spectator then receiving data-frames, this is handled when scanning for DLP networks. |
| + | |
| + | The spectator data includes the 48x48 icon, this has the same format as [[SMDH]]. |
| | | |
| This is the data starting at offset 0x0 for UDS PullPacket/SendTo: | | This is the data starting at offset 0x0 for UDS PullPacket/SendTo: |
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| |} | | |} |
| | | |
− | Total_frames is at least 0x4 normally. When a sysupdate is included, total_frames is 0x4+<total frames required for the titlelist(normally 0x1)>. | + | Total_frames is at least 0x4 normally. When a sysupdate is included, total_frames is 0x4+<total frames required for the titlelist(normally 0x1)>. Total_frames should be <=0x20, but the code doesn't check for this specific value. |
| + | |
| + | ==== Checksum ==== |
| + | The checksum seed is the 4-byte output from [[PS:EncryptDecryptAes|encrypting]] zeros with AES-CTR using [[PSPXI:EncryptDecryptAes|keytype5]]. The CTR is the output from this: "for(i=0; i<0x10; i++)ctr[i] = ctrseed[i] ^ host_macaddress[i % 6];" This ctrseed is a fixed 0x10-byte random-data block stored in DLP-sysmodule .rodata. |
| + | This seed is initialized after connecting to/creating the DLP network. |
| + | |
| + | The checksum stored in the above data frame header is then calculated using this checksum seed. |
| + | |
| + | First, the calc_checksum is initialized to 0. Then calc_checksum is added with ''all'' words in the data frame loaded as big-endian, with the data-frame checksum cleared to zero here. If the frame_size isn't word-aligned, the remaining <4-bytes are loaded as big-endian for adding as well. |
| + | |
| + | Then this is run: |
| + | //During init before the above adding, shift and count are initialized: |
| + | //shift = (((u8*)&checksum_seed)[2] & 0xf) + 0x4; |
| + | //count = (((u8*)&checksum_seed)[3] & 0x7) + 0x2; |
| + | for(pos=0; pos<count; pos++)checksum = (checksum<<shift | checksum>>shift) ^ checksum_seed;//The u32 checksum_seed is byte-swapped on 3DS for this. |
| + | |
| + | Lastly the calculated checksum is written to output as big-endian(hence on 3DS it's byte-swapped before writing to output). |
| | | |
− | Frames: | + | ==== Frames ==== |
| {| class="wikitable" border="1" | | {| class="wikitable" border="1" |
| |- | | |- |
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| The structure of each spectator frame relative to "frame-specific payload" is described below. | | The structure of each spectator frame relative to "frame-specific payload" is described below. |
| | | |
− | ==== Metadata frame ==== | + | ===== Metadata frame ===== |
| {| class="wikitable" border="1" | | {| class="wikitable" border="1" |
| |- | | |- |
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| |- | | |- |
| | 0x0 | | | 0x0 |
− | | 0x4 | + | | 0x8 |
− | | u32, unknown. | + | | u64 DLP-child titleID. Must be a CTR TID-high, with the TID-high set for DLP-child. The low 4-bits of the TID-low must be clear. |
− | |-
| |
− | | 0x4
| |
− | | 0x4
| |
− | | u32, unknown.
| |
| |- | | |- |
| | 0x8 | | | 0x8 |
| | 0x2 | | | 0x2 |
− | | u16, unknown. | + | | u16, probably the DLP-child title-version. |
| |- | | |- |
| | 0xA | | | 0xA |
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| | 0xC | | | 0xC |
| | 0x4 | | | 0x4 |
− | | u32, unknown. | + | | u32, chunk_size. This is the chunk_size used for transferring the CIA. This is the exact size used for the FS .cia file-reads on the host, and the exact size used for [[Application_Manager_Services|AM]] CIA file-writes on the client(s). Normally this is 0x0003FFC0. This appears to be validated by the client at some point, using a large value for this triggers an "connection interrupted" error when trying to connect. |
| |- | | |- |
| | 0x10 | | | 0x10 |
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| If the u16 at frameheader+0x6 is less than 0x101, the 8-bytes at outptr are cleared to all-zero, instead of copying the data from offset 0x2E8. | | If the u16 at frameheader+0x6 is less than 0x101, the 8-bytes at outptr are cleared to all-zero, instead of copying the data from offset 0x2E8. |
| | | |
− | ==== Icon gfx frame ==== | + | ===== Icon gfx frame ===== |
| {| class="wikitable" border="1" | | {| class="wikitable" border="1" |
| |- | | |- |
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| |} | | |} |
| | | |
− | ==== Sysupdate titlelist frame ==== | + | ===== Sysupdate titlelist frame ===== |
| {| class="wikitable" border="1" | | {| class="wikitable" border="1" |
| |- | | |- |