Migration is a sysmodule designed for handling the Switch-to-Switch transfer system introduced in firmware [[4.0.0]].

With newer system-versions this sysmodule is only running when [[qlaunch]] is using migration from the relevant transfer menus (see [[Applet_Manager_services#ActivateMigrationService|ActivateMigrationService]]/[[Applet_Manager_services#DeactivateMigrationService|DeactivateMigrationService]]).

= mig:usr =
This is "nn::migration::user::IService".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [19.0.0+]
|-
| 1 || [20.0.0+]
|-
| 2 || [20.0.0+]
|-
| 10 || [7.0.0-19.0.1] TryGetLastUserMigrationInfo ([4.0.0-6.2.0] TryGetLastMigrationInfo)
|-
| 11 || [20.0.0+]
|-
| 100 || [7.0.0+] [[#CreateUserMigrationServer|CreateUserMigrationServer]] ([4.0.0-6.2.0] CreateServer)
|-
| 101 || [7.0.0+] [[#ResumeUserMigrationServer|ResumeUserMigrationServer]] ([4.0.0-6.2.0] ResumeServer)
|-
| 200 || [7.0.0+] [[#CreateUserMigrationClient|CreateUserMigrationClient]] ([4.0.0-6.2.0] CreateClient)
|-
| 201 || [7.0.0+] [[#ResumeUserMigrationClient|ResumeUserMigrationClient]] ([4.0.0-6.2.0] ResumeClient)
|-
| 1001 || [8.0.0-20.5.0] [[#GetSaveDataMigrationPolicyInfoAsync|GetSaveDataMigrationPolicyInfoAsync]]
|-
| 1010 || [7.0.0+] TryGetLastSaveDataMigrationInfo
|-
| 1100 || [7.0.0-19.0.1] [[#CreateSaveDataMigrationServer|CreateSaveDataMigrationServer]]
|-
| 1101 || [7.0.0+] [[#ResumeSaveDataMigrationServer|ResumeSaveDataMigrationServer]]
|-
| 1110 || [17.0.0+]
|-
| 1200 || [7.0.0+] [[#CreateSaveDataMigrationClient|CreateSaveDataMigrationClient]]
|-
| 1201 || [7.0.0+] [[#ResumeSaveDataMigrationClient|ResumeSaveDataMigrationClient]]
|-
| 2001 || [20.0.0+]
|-
| 2010 || [20.0.0+]
|-
| 2100 || [20.0.0+]
|-
| 2110 || [20.0.0+]
|-
| 2200 || [20.0.0+]
|-
| 2210 || [20.0.0+]
|-
| 2220 || [20.0.0+]
|-
| 2221 || [22.0.0+]
|-
| 2230 || [20.0.0+]
|-
| 2231 || [20.0.0+]
|-
| 2232 || [20.0.0+]
|-
| 2233 || [20.0.0+]
|-
| 2234 || [20.0.0+]
|-
| 2250 || [20.0.0+]
|-
| 2260 || [20.0.0+]
|-
| 2270 || [20.0.0+]
|-
| 2280 || [20.0.0+]
|-
| 2300 || [20.0.0+]
|-
| 2310 || [20.0.0+]
|-
| 2400 || [20.0.0+]
|-
| 2420 || [20.0.0+]
|}

== CreateUserMigrationServer ==
Takes a total of 0x18-bytes of input, a type-0x19 input buffer, a TransferMemory handle, returns an [[#IServer]].

== ResumeUserMigrationServer ==
Takes an input u32, a TransferMemory handle, returns an [[#IServer]].

== CreateUserMigrationClient ==
Takes an input u32, a type-0x19 input buffer, a TransferMemory handle, returns an [[#IClient]].

== ResumeUserMigrationClient ==
Takes an input u32, a TransferMemory handle, returns an [[#IClient]].

== GetSaveDataMigrationPolicyInfoAsync ==
Takes an [[NCM_services#ApplicationId|ApplicationId]], returns an [[#IAsyncSaveDataMigrationPolicyInfoContext]].

This is used by [[qlaunch]] before the actual savedata transfer is started.

This starts a network request for [[Network|save_data_migration_policy]].

[20.0.0+] This was stubbed. The network request is no longer done and the various [[#IAsyncSaveDataMigrationPolicyInfoContext|IAsyncSaveDataMigrationPolicyInfoContext]] cmds just return success (besides GetSystemEvent). GetSaveDataMigrationPolicyInfo just returns the data which was set during object creation.

== CreateSaveDataMigrationServer ==
Takes an u32 tmem_size, an [[Account_services|Uid]], an [[NCM_services#ApplicationId|ApplicationId]], a type-0x19 input buffer containing a [[#ServerProfile|ServerProfile]], a TransferMemory handle, returns an [[#IServer_2|IServer]].

== ResumeSaveDataMigrationServer ==
Takes an input u32 [[#Cmd1110|tmem_size]], a TransferMemory handle, returns an [[#IServer_2|IServer]].

== Cmd1110 ==
Takes an u32 tmem_size, an [[Account_services|Uid]], a type-0x19 input buffer containing a [[#ServerProfile|ServerProfile]], a type-0x5 input buffer containing an array of [[NCM_services#ApplicationId|ApplicationIds]], and a TransferMemory handle. Returns an [[#IServer_2|IServer]].

This is identical to [[#CreateSaveDataMigrationServer|CreateSaveDataMigrationServer]] except the input array is passed directly instead of from a single input [[NCM_services#ApplicationId|ApplicationId]].

The tmem_size must be at least 0x504BB0.

== CreateSaveDataMigrationClient ==
Takes an input u32 tmem_size, a type-0x19 input buffer containing a [[#ClientProfile|ClientProfile]], a TransferMemory handle, returns an [[#IClient_2|IClient]].

== ResumeSaveDataMigrationClient ==
Takes an input u32 tmem_size, a TransferMemory handle, returns an [[#IClient_2|IClient]].

== Cmd2100 ==
Takes 4-bytes of input, a type-0x19 input buffer containing a 0x100-byte struct, a handle. Returns an [[#IServer_3|IServer]].

== Cmd2110 ==
Takes 4-bytes of input, a handle. Returns an [[#IServer_3|IServer]].

== Cmd2200 ==
Takes 4-bytes of input, a type-0x19 input buffer containing a 0x100-byte struct, a handle. Returns an [[#IClient_3|IClient]].

On NX this just calls a logging func and returns an error.

== Cmd2210 ==
Takes 4-bytes of input, a handle. Returns an [[#IClient_3|IClient]].

On NX this just calls a logging func and returns an error.

== Cmd2250 ==
Takes a total of 0x18-bytes of input, a handle. Returns an [[#IUnknown|IUnknown]].

== Cmd2260 ==
Takes 4-bytes of input, a handle. Returns an [[#IUnknown|IUnknown]].

== Cmd2280 ==
Takes an input u64, returns an [[#IAsyncContext]].

This starts a network request for [[Network|transfer_events/%lld/rollback]].

== Cmd2300 ==
Takes a total of 0x18-bytes of input, a handle. Returns an [[#IUploader|IUploader]].

== Cmd2310 ==
Takes 4-bytes of input, a handle. Returns an [[#IUploader|IUploader]].

== Cmd2400 ==
Takes a total of 0x10-bytes of input, a handle. Returns an [[#IDownloader|IDownloader]].

== Cmd2420 ==
Takes 4-bytes of input, a handle. Returns an [[#IDownloader|IDownloader]].

== IServer ==
This is "nn::migration::user::IServer".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetUid
|-
| 1 || [[#GetServerProfile|GetServerProfile]]
|-
| 100 || PrepareAsync
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || WaitConnectionAsync
|-
| 201 || GetClientProfile
|-
| 202 || AcceptConnectionAsync
|-
| 203 || DeclineConnectionAsync
|-
| 300 || ProcessTransferAsync
|-
| 400 || CompleteAsync
|-
| 500 || Abort
|}

=== GetServerProfile ===
Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

== IClient ==
This is "nn::migration::user::IClient".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetClientProfile
|-
| 10 || CreateLoginSession
|-
| 11 || GetNetworkServiceAccountId
|-
| 12 || GetUserNickname
|-
| 13 || GetUserProfileImage
|-
| 100 || PrepareAsync
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || ScanServersAsync
|-
| 201 || ListServers
|-
| 210 || ConnectByServerIdAsync
|-
| 300 || GetStorageShortfall
|-
| 301 || GetTotalTransferInfo
|-
| 302 || GetImmigrantUid
|-
| 310 || GetCurrentTransferInfo
|-
| 311 || GetCurrentRelatedApplications
|-
| 320 || TransferNextAsync
|-
| 350 || SuspendAsync
|-
| 400 || CompleteAsync
|-
| 500 || Abort
|-
| 999 || DebugSynchronizeStateInFinalizationAsync
|}

== IAsyncContext ==
This is "nn::migration::detail::IAsyncContext".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetSystemEvent
|-
| 1 || Cancel
|-
| 2 || HasDone
|-
| 3 || GetResult
|}

== IAsyncSaveDataMigrationPolicyInfoContext ==
This is "nn::migration::detail::IAsyncSaveDataMigrationPolicyInfoContext".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetSystemEvent
|-
| 1 || Cancel
|-
| 2 || HasDone
|-
| 3 || GetResult
|-
| 100 || GetSaveDataMigrationPolicyInfo
|}

== IServer ==
This is "nn::migration::savedata::IServer".

This was added with [7.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetUid
|-
| 1 || [7.0.0-19.0.1] GetApplicationId
|-
| 2 || [[#GetServerProfile_2|GetServerProfile]]
|-
| 3 || [17.0.0+] [[#ListApplicationIds|ListApplicationIds]]
|-
| 100 || [[#PrepareAsync|PrepareAsync]]
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || [[#WaitConnectionAsync|WaitConnectionAsync]]
|-
| 201 || GetClientProfile
|-
| 202 || [20.0.0+] [[#GetClientProductModel|GetClientProductModel]]
|-
| 203 || [20.0.0+] [[#GetTransferEventId|GetTransferEventId]]
|-
| 204 || [22.0.0+]
|-
| 210 || [8.0.0+] [[#WaitAcceptanceAsync|WaitAcceptanceAsync]]
|-
| 220 || [21.0.0+]
|-
| 300 || [[#ProcessTransferAsync|ProcessTransferAsync]]
|-
| 400 || [[#CompleteAsync|CompleteAsync]]
|-
| 500 || [7.0.0-19.0.1] [[#Abort|Abort]]
|-
| 510 || [19.0.0-20.5.0] [[#AbortAsync|AbortAsync]]
|-
| 511 || [21.0.0+] [[#AbortAsync2|AbortAsync2]]
|-
| 998 || [8.0.0+] DebugTryGetState
|-
| 999 || [8.0.0+] [[#DebugWaitStateSynchronizationFinalizedAsync|DebugWaitStateSynchronizationFinalizedAsync]]
|}

=== GetServerProfile ===
Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

=== ListApplicationIds ===
Takes a s32 offset, a type-0x6 output buffer containing an array of [[NCM_services#ApplicationId|ApplicationIds]], returns a s32 total_out.

=== PrepareAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various other functionality, the async task also uses functionality similar to [[#GetSaveDataMigrationPolicyInfoAsync|GetSaveDataMigrationPolicyInfoAsync]], throwing an error if needed.

[20.0.0+] The above policy functionality is no longer present. This now eventually uses network request [[Network|transfer_events/start]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Calls a vfunc, returns 0 if ret is true.
* Handles state cleanup if needed.
* Calls a func. This uses various [[OLSC_services|olsc:s]] functionality.
* Sets the state flag which was used for the above cleanup.
* Calls a func which uses [[NS_services#IManagerForSystemService|IManagerForSystemService]] GetAccountId. The output is unused.
* Calls a vfunc, returns 0 if ret is true.
* Calls a func. This handles initializing the contents of the fs file used with [[#GetList|GetList]] with the output of [[Filesystem_services|FindSaveDataWithFilter]] with SaveDataSpaceId = User. A state field is also updated.
* Handles [[Sockets_services|sockets]]/etc initialization, enters a nifm block.
* Uses network request [[Network|transfer_events/start]]. The output [[Network|transfer_event_id]] from this func is copied into state.
* Nifm usage ends here. Handles [[Sockets_services|sockets]] cleanup, etc.

=== Cmd102 ===
No input, returns an output bool.

=== WaitConnectionAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Initializes the data used for the AdvertiseData.
* Calls a func which:
** Calls a func which handles [[LDN_services|ldn]] initialization and network creation. SetProtocol is also used with a value from state.
** Calls a func which:
*** Handles setup for the server socket.
*** Uses [[LDN_services|SetAdvertiseData]] with the above AdvertiseData buffer.
*** Waits for a ldn Node to connect, with timeout etc handling.
*** Then [[LDN_services|SetStationAcceptPolicy]] is used with value 3 (WhiteList), and [[LDN_services|AddAcceptFilterEntry]] is used.
** Calls a func which waits for a socket connection (with timeout etc), and handles socket setup for it.
** Uses [[LDN_services|SetAdvertiseData]] with buf/size = 0 (empty AdvertiseData).
** Uses [[LDN_services|SetStationAcceptPolicy]] with value 1 (AlwaysReject).
** Enters a loop waiting for a state field to become value 0x3 (network message [[#Initialize|Initialize]]/[[#Initialize|Initialize2]] handled). Two funcs are called repeatedly in this loop. These essentially receive [[#Messages|messages]] + process them ([[#Data|Data]] messages not allowed), and send the response network message.
** Updates state and returns 0.
* Calls a vfunc. When the ret is true:
** Calls a func, which receives [[#SendClientProfile|SendClientProfile]] and sends the response. Also calls a func to process the received data.
** Receives [[#RequestServerProfile|RequestServerProfile]] and sends the response.
* Otherwise when the vfunc ret is false:
** Calls a func identical to the first network-message func called in the above block, except a different func is called at the end.
** Runs the same [[#RequestServerProfile|RequestServerProfile]] handling as above.
** Calls a func. This calls a func, then receives [[#GetList|GetList]] and sends the response.
** Calls a func. This runs functionality similar to the earlier message-loop, except this waits for the state field to change to !=0x3 (any network message besides [[#Initialize|Initialize]]/[[#Initialize|Initialize2]] handled). The socket is closed, then a func is called which handles [[LDN_services|ldn]] + [[Sockets_services|sockets]] cleanup.
** Calls a func. This essentially calls the network-creation func from earlier, with the input AdvertiseData being the [[#AdvertiseData|Uuid]].
** Calls a func. This receives [[#Suspend|Suspend]] or [[#SynchronizeState|SynchronizeState]] and sends the response.
* Updates a state flag and returns 0.

=== GetClientProductModel ===
Unofficial name.

No input, returns an output u32.

This loads a field from state. This originates from the [[Settings_services#ProductModel|ProductModel]] field in the [[#SendClientProfile|SendClientProfile]] request.

=== GetTransferEventId ===
Unofficial name.

No input, returns an output s64.

This loads the [[#RequestServerProfile|transfer_event_id]] from state, with an error being returned when the value is -1.

=== Cmd204 ===
No input, returns an output [[NCM_services#ApplicationId|ApplicationId]].

This loads a field from state, with 0 being returned and out=0 when this is -1. Otherwise this is then used as an arrayindex to load the data copied to output (equivalent to [[#ListApplicationIds|ListApplicationIds]] with the state field as the offset).

=== WaitAcceptanceAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task essentially (after state validation) just calls a func which handles receiving + responding to a network message ([[#AcceptDecline|AcceptDecline]] or [[#Suspend|Suspend]]).

=== Cmd220 ===
No input, returns a 0x10-byte struct.

This gets the 0x10-byte struct in state, which was received by [[#WaitAcceptanceAsync|WaitAcceptanceAsync]] from [[#AcceptDecline|AcceptDecline]] (originates from [[#DeclineAsync2|DeclineAsync2]]).

=== ProcessTransferAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Verifies that the [[#WaitConnectionAsync|connected]] state flag is set.
* Calls a vfunc. When ret is false, call another vfunc.
* Call the above vfunc again. If the ret is still false, return an error.
* When a state flag is not set, calls a func.
** Calls a func. This receives [[#Suspend|Suspend]] or [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] and sends the response.
** When the output bool from [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] above is true, just return 0.
** Calls the same func as [[#WaitConnectionAsync|WaitConnectionAsync]], which has a message-loop + socket-closing and cleanup.
** Calls the same func as [[#TransferNextAsync|TransferNextAsync]] for using the network request.
** Abort if a state flag is not set.
** Calls the network-creation func from [[#WaitConnectionAsync|WaitConnectionAsync]], with the input AdvertiseData being the [[#AdvertiseData|Uuid]].
* Enters a loop.
** Calls a func.
*** Initializes stack data.
*** Calls a func. This receives [[#Suspend|Suspend]], [[#SynchronizeState|SynchronizeState]], or [[#PrepareTransfer|PrepareTransfer]] and sends the response. Besides handling Suspend afterwards, this also copies a field to output (this is the output s32 mentioned below).
*** Calls a vfunc. When ret is true, cleanup and return 0.
*** Receives [[#TransferNext|TransferNext]] and sends the response.
** Calls a vfunc. When ret is true, return 0.
** If the Result from the above func is within the fs range for ResultDataCorrupted, and the output s32 from the func is not negative:
*** When a state field is less than the above s32, set another state field to that s32.
*** Break from the loop.
** If the above func returned error, break from the loop.

=== CompleteAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* When the [[#WaitConnectionAsync|connected]] state flag is set:
** Calls the same two funcs as [[#DebugWaitStateSynchronizationFinalizedAsync|DebugWaitStateSynchronizationFinalizedAsync]].
** Handles closing the socket (similar to elsewhere).
** Calls the func which handles cleanup for [[LDN_services|ldn]] + [[Sockets_services|sockets]].
** Clears the connected state flag.
* Calls a vfunc, throwing an error when ret is false.
* Calls a func.
* Calls vfuncs, then returns.

=== Abort ===
No input/output.

This does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Runs essentially the same code-block as [[#CompleteAsync|CompleteAsync]] for the connected flag, without the network messages.
* When a vfunc returns true, call a func.
* Calls vfuncs then returns.

=== AbortAsync ===
Unofficial name.

No input, returns an [[#IAsyncContext|IAsyncContext]].

On 19.x the async task is the cmd impl func used by [[#Abort|Abort]].

=== AbortAsync2 ===
Unofficial name.

Takes an input bool, returns an [[#IAsyncContext|IAsyncContext]].

This is roughly the same as [[#AbortAsync|AbortAsync]] except for the additional functionality done by the async task (etc), for when the input bool is set.

The async task does the following in that block when the input bool is set (handling any errors as needed / calling any logging funcs as needed):
* This block also only runs when a vfunc ret is false.
** Calls a func.
*** Calls a func to get a state field, if this is -1 this then just returns 0.
*** Calls a func.
*** Handles [[Sockets_services|sockets]]/etc initialization.
*** Enters a block which uses nifm.
*** Uses network request [[Network|transfer_events/%lld/abort_transfer]].
*** Nifm usage ends here. Handles [[Sockets_services|sockets]] cleanup, etc.
** If the above func returned an error, depending on the Result this may call a func which logs a report with [[PSC_services|srepo]].

=== DebugWaitStateSynchronizationFinalizedAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Calls a func. This receives [[#Suspend|Suspend]] or [[#SynchronizeState|SynchronizeState]], then sends the response.
* Calls a func. This is basically identical to the above func, except a field written to stack is value 5 instead of 4.

== IClient ==
This is "nn::migration::savedata::IClient".

This was added with [7.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [[#GetClientProfile|GetClientProfile]]
|-
| 100 || GetConnectionRequirement
|-
| 101 || [20.0.0+]
|-
| 200 || ScanServersAsync
|-
| 201 || [[#ListServers|ListServers]]
|-
| 210 || [[#ConnectByServerIdAsync|ConnectByServerIdAsync]]
|-
| 220 || [8.0.0+] [[#AcceptAsync|AcceptAsync]]
|-
| 221 || [8.0.0-20.5.0] [[#DeclineAsync|DeclineAsync]]
|-
| 222 || [21.0.0+] [[#DeclineAsync2|DeclineAsync2]]
|-
| 300 || GetStorageShortfall
|-
| 301 || GetTotalTransferInfo
|-
| 302 || GetImmigrantUid
|-
| 303 || GetApplicationId
|-
| 304 || [17.0.0+] [[#ListApplicationIds|ListApplicationIds]]
|-
| 310 || GetCurrentTransferInfo
|-
| 320 || [[#TransferNextAsync|TransferNextAsync]]
|-
| 350 || [[#SuspendAsync|SuspendAsync]]
|-
| 400 || [[#CompleteAsync_2|CompleteAsync]]
|-
| 500 || [7.0.0-19.0.1] [[#Abort_2|Abort]]
|-
| 510 || [19.0.0+] [[#AbortAsync_2|AbortAsync]]
|-
| 996 || [8.0.0+] DebugTryGetState
|-
| 997 || [8.0.0+] [[#DebugSynchronizeStateInFinalization0Async|DebugSynchronizeStateInFinalization0Async]]
|-
| 998 || [8.0.0+] [[#DebugSynchronizeStateInFinalization1Async|DebugSynchronizeStateInFinalization1Async]]
|-
| 999 || [[#DebugSynchronizeStateFinalizedAsync|DebugSynchronizeStateFinalizedAsync]]
|}

=== GetClientProfile ===
Takes a type-0x1A output buffer containing a [[#ClientProfile|ClientProfile]].

=== Cmd101 ===
No input, returns an output bool.

=== ListServers ===
[20.0.0+] The struct size is now 0x130-bytes instead of 0x128-bytes.

=== ConnectByServerIdAsync ===
Takes an input 0x10-byte struct, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls the same olsc func as [[#PrepareAsync|PrepareAsync]].
* ...
* Loops through an array to find an entry matching the 0x10-bytes from {func input param}, returning an error if not found. (entryptr is the located entry once done)
* Calls a vfunc. If ret is false:
** Calls a func with entryptr+0x10, for copying the input 0x10-bytes into state.
** Calls a func with entryptr+0x20, for copying 0x8-bytes from the input into state.
** Calls a func with entryptr+0x10, for copying the input 0x10-bytes into state.
* Calls a func.
** Clears a state flag if needed.
** entryptr = { Calls a func which loops through an array to find an entry matching the 0x10-bytes from input. } An error is returned if not found.
** Copies 0x480-bytes from entryptr+0x10 to stack, which is later passed to the connect-network func below.
** Calls a func which initializes [[Sockets_services|sockets]] + [[LDN_services|ldn]] if needed (Initialize, SetProtocol(state_field), SetOperationMode(1), OpenStation).
** Then various funcs are called for socket setup / connecting to the network.
*** ldn [[LDN_services|Connect]] is used, retrying with timeout as needed.
*** The TCP socket is setup, and the server is connected to with the IP from the relevant ldn [[LDN_services|NodeInfo]] (GetNetworkInfo) for the AccessPoint.
** Calls a func. This checks a bool state flag. Each block calls a logging func, a func specific to this block (same params for both), and if this is the flag==false block the flag is then set.
*** The funcs called from the above flag-block are roughly same. These send a message, handle receiving a message, then send another message + receive a message. For flag==false these are [[#Messages|MessageId]] 0x0/0x1, while for flag==true these are MessageId 0x8/0x9.
** A func is called which copies 0x10-bytes from entryptr+0x10+0x26C into state.
* Clears stack. Calls a func.
* Calls a func. This uses network message [[#SendClientProfile|SendClientProfile]].
* Calls a vfunc.
* When ret is true:
** Calls a func. This uses network message [[#RequestServerProfile|RequestServerProfile]].
** Sets a state flag, then returns 0.
* Otherwise when the vfunc ret is false:
** Calls a func. This is very similar to the func for RequestServerProfile used above.
** Calls a func.
*** Clears stack, and calls a func.
*** Uses network message [[#GetList|GetList]].
*** Calls a func.
** Calls a func. (fs related?)
** Calls a func. This uses network message [[#Leave|Leave]]. Then the socket is closed. Lastly, a func is called which handles closing [[LDN_services|ldn]] (CloseStation, Finalize) and [[Sockets_services|sockets]].
** Calls a func.
** Clears stack. Enters a block which uses nifm.
*** Calls a func.
*** Clears stack.
*** Calls a func to get a state field.
*** Calls a func which uses network request [[Network|transfer_events/%lld/register_destination]].
** Nifm usage ends here.
** Calls a func.
** Calls a func which handles [[Sockets_services|sockets]] cleanup.
** Calls a func. This essentially does ldn setup again / reconnects to the network. The previously mentioned network messages func used after connection is then called here, with the bool flag being previously updated it would now use MessageId 0x8/0x9. State is also updated.
** Calls a func. This uses network message [[#SynchronizeState|SynchronizeState]] with value 1. Afterwards it then calls a vfunc.
** Sets a state flag, then returns 0.

=== AcceptAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does essentially the following:
* Validates that the state flag which was set at the end of [[#ConnectByServerIdAsync|ConnectByServerIdAsync]] is set.
* Sends [[#AcceptDecline|AcceptDecline]], then receives network data.

=== DeclineAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task is the same as [[#AcceptAsync|AcceptAsync]] except for the transferred data, and also does the following after the transfer:
* Closes the socket.
* Calls the func which handles cleanup for [[LDN_services|ldn]] + [[Sockets_services|sockets]].
* Clears the state flag which was set at the end of [[#ConnectByServerIdAsync|ConnectByServerIdAsync]], then returns 0.

=== DeclineAsync2 ===
Unofficial name.

Takes an input 0x10-byte struct, returns an [[#IAsyncContext|IAsyncContext]].

Same as [[#DeclineAsync|DeclineAsync]] except for the transferred data.

=== TransferNextAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls vfuncs.
* Calls various funcs to check state. This includes calling a fs-related func?
* If a state flag is not set, a func is called:
** Uses network message [[#PrepareTransferDisconnect|PrepareTransferDisconnect]].
** If the state fields checked by [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] for header+0x1 match, this just returns.
** Calls the func which handles disconnecting from the network.
** Calls two funcs.
** Calls a func. This handles using network request [[Network|transfer_events/%lld/save_datas/%lld/generate_key_seed_package]] and uses the relevant [[Filesystem_services|fs]] cmds. [[Filesystem_services|ISaveDataTransferManagerWithDivision SetMode]] is also used with value 1. The previously mentioned state flag is then set.
** Calls the func which handles reconnecting to the network.
* Calls a func when a previously loaded state field is 0.
* Calls a func. (fs related?)
* Calls a func which validates the output from an earlier func.
* Logs a report with [[PSC_services|srepo]].
* Uses network message [[#PrepareTransfer|PrepareTransfer]]. Uses [[Filesystem_services|ISaveDataTransferManagerWithDivision SetLocalKeySeedPackage]] with the relevant response data.
* Logs a report with [[PSC_services|srepo]]. "tr_size" is logged by adding two u64 fields from the 0x20-byte struct returned by [[#PrepareTransfer|PrepareTransfer]]: +0x18 and +0x8.
* Calls a func.
* Calls a func for getting state data.
* Calls a func which writes the various input to the output struct. This is then passed to the the following func which is called:
** Calls a func.
** Uses network message [[#TransferNext|TransferNext]].
** Calls a func.
* Logs a report with [[PSC_services|srepo]].
* If the output from two funcs which load state match, calls a func.
* Cleanup, then returns.

=== SuspendAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task essentially just verifies the [[#ConnectByServerIdAsync|connected]] state flag is set, uses network message [[#Suspend|Suspend]], closes the socket, calls the func which closes [[LDN_services|ldn]] + [[Sockets_services|sockets]], then clears the connected state flag.

=== CompleteAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls a vfunc. When the ret is false:
** Throws an error if not [[#ConnectByServerIdAsync|connected]].
** If a state flag is not set, calls the same func as [[#TransferNextAsync|TransferNextAsync]] for generate_key_seed_package.
** Calls the same func as [[#DebugSynchronizeStateInFinalization0Async|DebugSynchronizeStateInFinalization0Async]].
** Calls the same func as [[#DebugSynchronizeStateInFinalization1Async|DebugSynchronizeStateInFinalization1Async]].
** Calls the same func as [[#DebugSynchronizeStateFinalizedAsync|DebugSynchronizeStateFinalizedAsync]].
** Calls a func which handles disconnecting from the network, without using the network message. This also clears the connected state flag.
* Calls the same vfunc as above again, throwing an error if the ret is still false.
* Handles [[Sockets_services|sockets]] initialization.
* Calls a func.
* Enters a block which uses nifm.
* Calls a func which uses network request [[Network|transfer_events/%lld/finish_transfer]].
* Nifm usage ends here.
* Handles cleanup for [[Sockets_services|sockets]].
* When successful at this point it runs the following block:
** Calls a func. (fs related?)
** Calls a func.
** Calls a func, which logs a report with [[PSC_services|srepo]].
** Calls a vfunc.
** Calls a vfunc (with locking before/after).

=== Abort ===
No input/output.

When the [[#ConnectByServerIdAsync|connected]] state flag is set, this runs code similar to [[#SuspendAsync|SuspendAsync]], without the network message. Then various vfuncs are called. Various funcs are also called as needed (fs related?).

=== AbortAsync ===
Unofficial name.

No input, returns an [[#IAsyncContext|IAsyncContext]].

On 19.x the async task is the cmd impl func used by [[#Abort_2|Abort]].

=== DebugSynchronizeStateInFinalization0Async ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls vfuncs and uses network message [[#SynchronizeState|SynchronizeState]] with value 3.

=== DebugSynchronizeStateInFinalization1Async ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls vfuncs and uses network message [[#SynchronizeState|SynchronizeState]] with value 4.

=== DebugSynchronizeStateFinalizedAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls a vfunc and uses network message [[#SynchronizeState|SynchronizeState]] with value 5.

== IServer ==
This is "nn::migration::device::IServer".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [[#GetServerProfile_3|GetServerProfile]]
|-
| 10 ||
|-
| 20 ||
|-
| 21 ||
|-
| 30 ||
|-
| 40 ||
|-
| 50 ||
|-
| 60 || [22.0.0+]
|-
| 100 ||
|-
| 110 ||
|-
| 111 ||
|-
| 120 || [20.0.0-20.5.0]
|-
| 121 || [21.0.0+]
|-
| 130 ||
|-
| 200 ||
|-
| 230 ||
|-
| 290 ||
|-
| 300 ||
|-
| 400 ||
|-
| 510 || [20.0.0-20.5.0]
|-
| 511 || [21.0.0+]
|-
| 900 ||
|}

=== GetServerProfile ===
Unofficial name.

Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

=== Cmd230 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/start]].

=== Cmd510 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/abort_transfer]].

== IClient ==
This is "nn::migration::device::IClient".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 10 ||
|-
| 20 ||
|-
| 30 ||
|-
| 100 ||
|-
| 110 ||
|-
| 111 ||
|-
| 200 ||
|-
| 210 ||
|-
| 220 ||
|-
| 230 ||
|-
| 240 ||
|-
| 250 ||
|-
| 290 ||
|-
| 300 ||
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 340 ||
|-
| 400 ||
|-
| 500 ||
|-
| 610 ||
|-
| 700 ||
|-
| 710 ||
|-
| 720 ||
|}

== IUnknown ==
This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 ||
|-
| 1 ||
|-
| 2 ||
|-
| 3 ||
|-
| 100 ||
|-
| 110 ||
|}

== IUploader ==
This is "nn::migration::device::IUploader".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 90 ||
|-
| 100 || [20.0.0-20.5.0]
|-
| 101 || [21.0.0+]
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 340 ||
|-
| 350 ||
|-
| 360 || [22.0.0+]
|-
| 400 ||
|-
| 500 ||
|-
| 610 || [20.0.0-20.5.0]
|-
| 611 || [21.0.0+]
|-
| 900 ||
|}

=== Cmd100 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/start]].

=== Cmd500 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/finish_upload]].

=== Cmd610 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/abort_upload]].

=== Cmd900 ===
Takes a total of 4-bytes of input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task may call the same network-request func as [[#Cmd500]].

== IDownloader ==
This is "nn::migration::device::IDownloader".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 10 ||
|-
| 20 ||
|-
| 30 ||
|-
| 90 ||
|-
| 100 ||
|-
| 300 ||
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 390 || [21.0.0+]
|-
| 400 ||
|-
| 500 ||
|-
| 610 ||
|-
| 620 ||
|-
| 900 ||
|}

=== Cmd500 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/finish_download]].

=== Cmd900 ===
Takes a total of 4-bytes of input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task may call the same network-request func as [[#Cmd500_2|Cmd500]].

= ServerProfile =
This is a 0x100-byte struct.

It's unknown whether user/savedata/device use the same struct (size is the same for these).

Any data here which is initialized is usually zeros?

= ClientProfile =
This is a 0x100-byte struct.

It's unknown whether user/savedata/device use the same struct (size is the same for these).

This is usually all-zeros with savedata?

= Protocol =
Once connected with [[LDN_services|ldn]], the client node connects to the server with TCP port 441.

== AdvertiseData ==
These sections document the initial [[LDN_services|AdvertiseData]] used by migration.

The salt used with hashing below is the same regardless of the AdvertiseData.

Immediately after a socket connection is setup, the AdvertiseData is set to size=0. Later when the server recreates the network it also sets the AdvertiseData to {0x10-byte Uuid previously used below}.

The Uuid used below is generated with <code>nn::util::GenerateUuid</code>.

=== user ===
Used by nn::migration::user::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || AccountId
|-
| 0x8 || 0x58 || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* AccountId
* ServerProfile
* 0x100-byte salt

=== savedata ===
Used by nn::migration::savedata::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || AccountId
|-
| 0x8 || 0x8 || ApplicationId
|-
| 0x10 || 0x50 || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* AccountId
* ApplicationId
* ServerProfile
* 0x100-bytes salt

[20.0.0+]:
{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Uuid
|-
| 0x10 || 0x8 || AccountId
|-
| 0x18 || 0x8 || ApplicationId
|-
| 0x20 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|-
| 0x24 || 0x4 || Reserved
|-
| 0x28 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x128 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* Uuid
* AccountId
* ApplicationId
* ProductModel
* ServerProfile
* 0x100-bytes salt

=== device ===
Used by nn::migration::device::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Uuid
|-
| 0x10 || 0x40 (0x8*0x8) || Array of u64s with the below count.
|-
| 0x50 || 0x4 || Count for the above array.
|-
| 0x54 || 0xC || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* Uuid
* +0x10 size 0x40-bytes
* +0x50 size 0x4-bytes
* ServerProfile
* 0x100-bytes salt

== Messages ==
Names are unofficial.

Messages sent over the TCP socket start with the following header:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || MessageId
|-
| 0x1 || 0x7 || Reserved
|}

Data specific to each message follows.

Messages are encrypted with AES-128-GCM (excluding the [[#KeyExchange|KeyExchange]] messages). The key is derived during the messsage-handling for KeyExchange. The 0xC-byte nonce is the 0x8-bytes derived by [[#KeyExchange|KeyExchange]], followed by a big-endian u32 counter (starting at 0x0). This counter is incremented each time a message is encrypted/decrypted. The GCM AAD is not used.

The message size must match the expected fixed-size for the MessageId.

Offsets in the below sections are relative to header+0 (for encrypted messages, this is the plaintext payload instead).

Message requests are sent by the client to the server, then (unless noted otherwise) a response with the same MessageId is sent to the client from the server. The first sent request is [[#KeyExchange|KeyExchange]].

For GCM encrypted messages, the encrypted data starts at +0x8, with the 0x10-byte AES-128-GCM MAC tag immediately afterwards. The first 0xC-bytes of plaintext is the nonce (which must match the expected one during decryption), followed by the payload (can be empty).

{| class="wikitable" border="1"
|-
! MessageId (client/server) || Description
|-
| 0x0 || [[#KeyExchange|KeyExchange]]
|-
| 0x1 || [[#Initialize|Initialize]]
|-
| 0x8 || [[#Challenge|Challenge]]
|-
| 0x9 || [[#Initialize|Initialize2]]
|-
| 0x10 || [[#Leave|Leave]]
|-
| 0x80 || [[#Data|Data]]
|-
| 0xFF || [[#Error|Error]]
|}

=== KeyExchange ===
Request:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x8 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|-
| 0x28 || 0x10 || CMAC ([[SPL_services|ComputeCmac]]) over the above 0x20-bytes, followed by 0x20-bytes from state.
|}

Response:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x8 || 0x10 || Ctr for [[SPL_services|ComputeCtr]] with the below data (generated with [[SPL_services|GenerateRandomBytes]]).
|-
| 0x18 || 0x70 || Data encrypted with [[SPL_services|ComputeCtr]].
|-
| 0x88 || 0x10 || CMAC over the above plaintext data ([[SPL_services|ComputeCmac]]).
|}

The plaintext data has the following structure:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x28 || Passphrase for key derivation (generated with [[SPL_services|GenerateRandomBytes]]).
|-
| 0x28 || 0x20 || Must match the random data previously sent by the client.
|-
| 0x48 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|-
| 0x68 || 0x8 || Zeros
|}

The keyslot for spl is setup with: <code>GenerateAesKek(AccessKey, KeySource, Generation, Option=0); LoadAesKey(keyslot, AccessKey, KeySource);</code>

{| class="wikitable" border="1"
|-
! System Version || Generation
|-
| [4.0.0] || 0x0
|-
| [5.0.0-5.1.0] || 0x5
|-
| [6.0.0-6.2.0] || 0x6
|-
| [7.0.0-8.0.0] || 0x8
|-
| [9.0.0] || 0xA
|-
| [9.1.0-12.1.0] || 0xB
|-
| [13.0.0] || 0xD
|-
| [14.0.0] || 0xE
|-
| [15.0.0] || 0xF
|-
| [16.0.0] || 0x10
|-
| [17.0.0+] || 0x11
|}

PBKDF2-HMAC-SHA256 is used with the first 0x28-bytes of the above plaintext as the passphrase, a 0x20-byte salt from fixed global data, iterations=1000, and i=1. The first 0x10-bytes of the output HMAC then used as the AES-128-GCM key for later messages. The following 0x8-bytes is used as the first 0x8-bytes of the nonce.

=== Initialize ===
This request is sent after [[#KeyExchange|KeyExchange]]. The Initialize2 request is sent after [[#Challenge|Challenge]].

Plaintext request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Must match the 0x20-bytes which is used for [[#KeyExchange|KeyExchange]] response_plaintext+0x48.
|}

The plaintext response payload is empty.

When handling the response, the client sets a state flag. The Initialize2 message is the same as Initialize, except that state field isn't updated during response handling.

=== Challenge ===
This is the first request sent after reconnecting to the server, when an existing connection was previously in use.

Plaintext request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|}

Plaintext response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Must match the random data previously sent by the client.
|-
| 0x20 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]]. Copied into state by the client.
|}

=== Leave ===
This is sent by the client prior to closing the socket and temporarily leaving the ldn network.

The plaintext request/response payload are empty.

=== Data ===
This is used by the client to send additional data following the message, likewise by the server in response.

Plaintext payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || Big-endian data chunksize.
|-
| 0x8 || 0x8 || Big-endian data size.
|}

The additional data is encrypted the same as if it were a message without the message-header, in chunks of up to {above chunksize}.

Both fields must be non-zero, and the chunksize must match 0x100000.

The first chunk starts with a header, with the rest being the actual payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || DataMessageId
|-
| 0x1 || 0x7 || Data for the message if any, normally all-zero.
|}

The DataMessageId in the response received by the client must match one of the expected values, which is usually only the value previously sent in the request. The received size must also match the expected value.

{| class="wikitable" border="1"
|-
! DataMessageId (client/server) || Description
|-
| 0x10 || [[#RequestServerProfile|RequestServerProfile]]
|-
| 0x11 || [[#SendClientProfile|SendClientProfile]]
|-
| 0x12 || [[#GetList|GetList]]
|-
| 0x20 || [[#AcceptDecline|AcceptDecline]]
|-
| 0xE0 || [[#PrepareTransferDisconnect|PrepareTransferDisconnect]]
|-
| 0xE1 || [[#PrepareTransfer|PrepareTransfer]]
|-
| 0xE2 || [[#TransferNext|TransferNext]]
|-
| 0xF0 || [[#SynchronizeState|SynchronizeState]]
|-
| 0xFF || [[#Suspend|Suspend]]
|}

==== RequestServerProfile ====
This is sent by the client following the last vfunc call in [[#ConnectByServerIdAsync|ConnectByServerIdAsync]] where the bool ret is checked, with both true/false blocks. This follows [[#SendClientProfile|SendClientProfile]].

The request only contains the header.

Response payload (0x148-byte struct, which has the following layout):

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || Value 0x1.
|-
| 0x1 || 0x7 || Zeros
|-
| 0x8 || 0x4 || SystemVersion (same form as [[#SendClientProfile|SendClientProfile]])
|-
| 0xC || 0x10 || Uuid (from <code>nn::util::GenerateUuid()</code>)
|-
| 0x1C || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x11C || 0x4 || ApplicationIdsCount (arraycount from [[#Cmd1110]])
|-
| 0x120 || 0x8 || ApplicationId (first ApplicationId from the input array)
|-
| 0x128 || 0x8 || [[Network|transfer_event_id]] from the [[#PrepareAsync|/start]] request, then used with the remaining network requests.
|-
| 0x130 || 0x4 || Value 0x1.
|-
| 0x134 || 0x10 || Zeros with savedata.
|-
| 0x144 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|}

When the aforementioned vfunc returned true, the client only uses the response data for verifying that various fields match state. Otherwise when false the client uses this data, in which case:
* The ProductModel must be within [[Settings_services#ProductModel|range]] for Nintendo Switch / Nintendo Switch 2.
* Calls the same func as [[#SendClientProfile|SendClientProfile]] with the above SystemVersion and ProductModel, returning an error if false is returned.
* The u8 at +0x0 must match 0x1.
* The Uuid must be non-zero.
* The ApplicationIdsCount must be 0x1-0x800.
* The ApplicationId must match state.
* Copies data into state, etc.

==== SendClientProfile ====
Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x100 || [[#ClientProfile|ClientProfile]]
|-
| 0x100 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|-
| 0x104 || 0x4 || [[System_Version_Title|SystemVersion]]. u32 in the form: <code>(Major<<16) | (Minor<<8) | Micro</code>
|}

The response only contains the header.

When the vfunc ret at the end of [[#WaitConnectionAsync|WaitConnectionAsync]] is true, the server just validates that the first 0x104-bytes of the above request match state. Otherwise when that vfunc ret is false:
* The ProductModel must be within [[Settings_services#ProductModel|range]] for Nintendo Switch / Nintendo Switch 2.
* Calls a func with the request SystemVersion and ProductModel, returning an error if false is returned.
** If <ProductModel is within the range for Nintendo Switch>: return SystemVersion == <SystemVersion value loaded for the server system>.
** Otherwise: return SystemVersion > <min_sysver> && <ProductModel is within the range for Nintendo Switch 2>.
* Then the ClientProfile/ProductModel are copied into state, etc.

==== GetList ====
This is sent by the client following [[#RequestServerProfile|RequestServerProfile]], where the vfunc mentioned there returned false.

The request only contains the header.

Initial response payload, after the header:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x4 || Data size.
|}

The remaining messages contain the data payload with the above size.

This is used for transferring the contents of a fs file (server reads from it, client writes to a file).

With savedata this is an array where each entry is 0x50-bytes, where each entry has the structure (converted from [[Filesystem_services#SaveDataInfo|SaveDataInfo]]):

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || Type: 0 = SaveDataType System, 1 = SaveDataType Account, 2 = SaveDataType Device.
|-
| 0x1 || 0x1 || IsAccountIdValid (whether loading the AccountId was successful when UserId is non-zero)
|-
| 0x4 || 0x4 || Output from sdk func <code>nn::fs::QuerySaveDataRequiredSizeForImport</code> (on NX the input PlatformIdForSaveDataSizeCalculation is 1).
|-
| 0x8 || 0x8 || SaveDataId
|-
| 0x10 || 0x10 || UserId
|-
| 0x20 || 0x8 || AccountId ([[NS_services#IManagerForSystemService|IManagerForSystemService]] GetAccountId with the UserId, when loaded successfully where UserId is set)
|-
| 0x28 || 0x8 || ApplicationId (for System, SystemSaveDataId)
|-
| 0x30 || 0x4 || [[NS_services#IApplicationVersionInterface|LaunchRequiredVersion]] (from GetLaunchRequiredVersion, for Account/Device)
|-
| 0x38 || 0x18 || [[OLSC_services#UserSaveDataProperty|UserSaveDataProperty]], from GetUserSaveDataProperty. Only with Account. If IsAccountIdValid is not set this is cleared instead.
|}

[[Filesystem_services|GetSaveDataCommitId]] is also used when initializing the above entry, however the output is unused besides returning the Result on failure.

==== AcceptDecline ====
This is sent by the client via [[#AcceptAsync|AcceptAsync]]/[[#DeclineAsync|DeclineAsync]]/[[#DeclineAsync2|DeclineAsync2]].

Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || 0 = Decline, 1 = Accept.
|}

[21.0.0+]:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Input from [[#DeclineAsync2|DeclineAsync2]] (zeros with Accept).
|}

At +0x1 in the header prior to this request payload, after DataMessageId is now:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x1 || 0x1 || 0 = Decline, 1 = Accept.
|}

The response only contains the header.

==== PrepareTransferDisconnect ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]] if a state flag is not set, prior to temporarily disconnecting from the network for using network request [[Network|transfer_events/%lld/save_datas/%lld/generate_key_seed_package]].

The request only contains the 0x4-byte header. The bool at header+0x1 (after DataMessageId) is set to <code>statefield==other_statefield</code>. This bool indicates whether the previously mentioned network request is used.

The response only contains the 0x4-byte header.

==== PrepareTransfer ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]] (after [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] if using it was enabled).

The request only contains the header, which besides the DataMessageId contains:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x4 || 0x4 || s32, must not be negative.
|}

Response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 ||
|-
| 0x20 || 0x200 || [[Filesystem_services|LocalKeySeedPackage]]
|}

==== TransferNext ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]], after [[#PrepareTransfer|PrepareTransfer]].

The request only contains the header.

Response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || Zeros
|-
| 0x8 || Rest of message || Transfer payload.
|}

With savedata the transfer payload is the output from exporting savedata from [[Filesystem_services|ISaveDataTransferManagerWithDivision]] (see [[#Notes]]), which the client then imports.

==== SynchronizeState ====
The client sends this via [[#ConnectByServerIdAsync|ConnectByServerIdAsync]], [[#CompleteAsync_2|CompleteAsync]], and DebugSynchronizeState*.

Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x4 || See below.
|}

{| class="wikitable" border="1"
|-
! Value || Description
|-
| 1 || Can be used by [[#ConnectByServerIdAsync|ConnectByServerIdAsync]].
|-
| 3 || [[#DebugSynchronizeStateInFinalization0Async|InFinalization0]]
|-
| 4 || [[#DebugSynchronizeStateInFinalization1Async|InFinalization1]]
|-
| 5 || [[#DebugSynchronizeStateFinalizedAsync|Finalized]]
|}

The response only contains the header.

==== Suspend ====
The client sends this via [[#SuspendAsync|SuspendAsync]]

The request only contains the header.

The response only contains the header.

The server returns an error following handling Suspend.

=== Error ===
This can be sent by the server to the client to signal that an error occurred.

Plaintext response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || ErrorType
|}

If a state field is valid, it's used to load a Result from an array, otherwise the Result is determined from the above ErrorType.

= Notes =
Savedata transfer ("nn::migration::savedata::IServer"/"nn::migration::savedata::IClient") requires that accounts are linked to the same network-account. acc:su [[NS_services#IManagerForSystemService|IManagerForSystemService]] GetAccountId is used here. The server stores this Id into state, and also stores it in the [[LDN_services|ldn]] AdvertiseData. The client also verifies the Id in AdvertiseData against the Id from GetAccountId for the account(s) being used, during ScanServersAsync.

[20.0.0+] [[Filesystem_services#ISaveDataTransferManagerWithDivision|ISaveDataTransferManagerWithDivision]] is now used instead of ISaveDataTransferManager. Besides [[Filesystem_services|SetKeySeedPackage]] being used now as needed, [[Filesystem_services|SetLocalKeySeedPackage]] is now used by the relevant functionality in [[#IClient_2|IClient]] TransferNextAsync.

[S2] System Settings now has an additional menu once send-savedata is selected, for selecting whether to send to Nintendo Switch or Nintendo Switch 2. If Switch 2 is selected, and there's a S1 receiving, the S2 will display a message regarding wrong target system. The receiving system also displays an error. Note that savedata for S2-only applications is only listed with the dest-S2 option (S1-applications are also listed).

[[Category:Services]]

Migration services

2026-05-06T15:18:09Z

Yellows8:

Migration is a sysmodule designed for handling the Switch-to-Switch transfer system introduced in firmware [[4.0.0]].

With newer system-versions this sysmodule is only running when [[qlaunch]] is using migration from the relevant transfer menus (see [[Applet_Manager_services#ActivateMigrationService|ActivateMigrationService]]/[[Applet_Manager_services#DeactivateMigrationService|DeactivateMigrationService]]).

= mig:usr =
This is "nn::migration::user::IService".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [19.0.0+]
|-
| 1 || [20.0.0+]
|-
| 2 || [20.0.0+]
|-
| 10 || [7.0.0-19.0.1] TryGetLastUserMigrationInfo ([4.0.0-6.2.0] TryGetLastMigrationInfo)
|-
| 11 || [20.0.0+]
|-
| 100 || [7.0.0+] [[#CreateUserMigrationServer|CreateUserMigrationServer]] ([4.0.0-6.2.0] CreateServer)
|-
| 101 || [7.0.0+] [[#ResumeUserMigrationServer|ResumeUserMigrationServer]] ([4.0.0-6.2.0] ResumeServer)
|-
| 200 || [7.0.0+] [[#CreateUserMigrationClient|CreateUserMigrationClient]] ([4.0.0-6.2.0] CreateClient)
|-
| 201 || [7.0.0+] [[#ResumeUserMigrationClient|ResumeUserMigrationClient]] ([4.0.0-6.2.0] ResumeClient)
|-
| 1001 || [8.0.0-20.5.0] [[#GetSaveDataMigrationPolicyInfoAsync|GetSaveDataMigrationPolicyInfoAsync]]
|-
| 1010 || [7.0.0+] TryGetLastSaveDataMigrationInfo
|-
| 1100 || [7.0.0-19.0.1] [[#CreateSaveDataMigrationServer|CreateSaveDataMigrationServer]]
|-
| 1101 || [7.0.0+] [[#ResumeSaveDataMigrationServer|ResumeSaveDataMigrationServer]]
|-
| 1110 || [17.0.0+]
|-
| 1200 || [7.0.0+] [[#CreateSaveDataMigrationClient|CreateSaveDataMigrationClient]]
|-
| 1201 || [7.0.0+] [[#ResumeSaveDataMigrationClient|ResumeSaveDataMigrationClient]]
|-
| 2001 || [20.0.0+]
|-
| 2010 || [20.0.0+]
|-
| 2100 || [20.0.0+]
|-
| 2110 || [20.0.0+]
|-
| 2200 || [20.0.0+]
|-
| 2210 || [20.0.0+]
|-
| 2220 || [20.0.0+]
|-
| 2221 || [22.0.0+]
|-
| 2230 || [20.0.0+]
|-
| 2231 || [20.0.0+]
|-
| 2232 || [20.0.0+]
|-
| 2233 || [20.0.0+]
|-
| 2234 || [20.0.0+]
|-
| 2250 || [20.0.0+]
|-
| 2260 || [20.0.0+]
|-
| 2270 || [20.0.0+]
|-
| 2280 || [20.0.0+]
|-
| 2300 || [20.0.0+]
|-
| 2310 || [20.0.0+]
|-
| 2400 || [20.0.0+]
|-
| 2420 || [20.0.0+]
|}

== CreateUserMigrationServer ==
Takes a total of 0x18-bytes of input, a type-0x19 input buffer, a TransferMemory handle, returns an [[#IServer]].

== ResumeUserMigrationServer ==
Takes an input u32, a TransferMemory handle, returns an [[#IServer]].

== CreateUserMigrationClient ==
Takes an input u32, a type-0x19 input buffer, a TransferMemory handle, returns an [[#IClient]].

== ResumeUserMigrationClient ==
Takes an input u32, a TransferMemory handle, returns an [[#IClient]].

== GetSaveDataMigrationPolicyInfoAsync ==
Takes an [[NCM_services#ApplicationId|ApplicationId]], returns an [[#IAsyncSaveDataMigrationPolicyInfoContext]].

This is used by [[qlaunch]] before the actual savedata transfer is started.

This starts a network request for [[Network|save_data_migration_policy]].

[20.0.0+] This was stubbed. The network request is no longer done and the various [[#IAsyncSaveDataMigrationPolicyInfoContext|IAsyncSaveDataMigrationPolicyInfoContext]] cmds just return success (besides GetSystemEvent). GetSaveDataMigrationPolicyInfo just returns the data which was set during object creation.

== CreateSaveDataMigrationServer ==
Takes an u32 tmem_size, an [[Account_services|Uid]], an [[NCM_services#ApplicationId|ApplicationId]], a type-0x19 input buffer containing a [[#ServerProfile|ServerProfile]], a TransferMemory handle, returns an [[#IServer_2|IServer]].

== ResumeSaveDataMigrationServer ==
Takes an input u32 [[#Cmd1110|tmem_size]], a TransferMemory handle, returns an [[#IServer_2|IServer]].

== Cmd1110 ==
Takes an u32 tmem_size, an [[Account_services|Uid]], a type-0x19 input buffer containing a [[#ServerProfile|ServerProfile]], a type-0x5 input buffer containing an array of [[NCM_services#ApplicationId|ApplicationIds]], and a TransferMemory handle. Returns an [[#IServer_2|IServer]].

This is identical to [[#CreateSaveDataMigrationServer|CreateSaveDataMigrationServer]] except the input array is passed directly instead of from a single input [[NCM_services#ApplicationId|ApplicationId]].

The tmem_size must be at least 0x504BB0.

== CreateSaveDataMigrationClient ==
Takes an input u32 tmem_size, a type-0x19 input buffer containing a [[#ClientProfile|ClientProfile]], a TransferMemory handle, returns an [[#IClient_2|IClient]].

== ResumeSaveDataMigrationClient ==
Takes an input u32 tmem_size, a TransferMemory handle, returns an [[#IClient_2|IClient]].

== Cmd2100 ==
Takes 4-bytes of input, a type-0x19 input buffer containing a 0x100-byte struct, a handle. Returns an [[#IServer_3|IServer]].

== Cmd2110 ==
Takes 4-bytes of input, a handle. Returns an [[#IServer_3|IServer]].

== Cmd2200 ==
Takes 4-bytes of input, a type-0x19 input buffer containing a 0x100-byte struct, a handle. Returns an [[#IClient_3|IClient]].

On NX this just calls a logging func and returns an error.

== Cmd2210 ==
Takes 4-bytes of input, a handle. Returns an [[#IClient_3|IClient]].

On NX this just calls a logging func and returns an error.

== Cmd2250 ==
Takes a total of 0x18-bytes of input, a handle. Returns an [[#IUnknown|IUnknown]].

== Cmd2260 ==
Takes 4-bytes of input, a handle. Returns an [[#IUnknown|IUnknown]].

== Cmd2280 ==
Takes an input u64, returns an [[#IAsyncContext]].

This starts a network request for [[Network|transfer_events/%lld/rollback]].

== Cmd2300 ==
Takes a total of 0x18-bytes of input, a handle. Returns an [[#IUploader|IUploader]].

== Cmd2310 ==
Takes 4-bytes of input, a handle. Returns an [[#IUploader|IUploader]].

== Cmd2400 ==
Takes a total of 0x10-bytes of input, a handle. Returns an [[#IDownloader|IDownloader]].

== Cmd2420 ==
Takes 4-bytes of input, a handle. Returns an [[#IDownloader|IDownloader]].

== IServer ==
This is "nn::migration::user::IServer".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetUid
|-
| 1 || [[#GetServerProfile|GetServerProfile]]
|-
| 100 || PrepareAsync
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || WaitConnectionAsync
|-
| 201 || GetClientProfile
|-
| 202 || AcceptConnectionAsync
|-
| 203 || DeclineConnectionAsync
|-
| 300 || ProcessTransferAsync
|-
| 400 || CompleteAsync
|-
| 500 || Abort
|}

=== GetServerProfile ===
Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

== IClient ==
This is "nn::migration::user::IClient".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetClientProfile
|-
| 10 || CreateLoginSession
|-
| 11 || GetNetworkServiceAccountId
|-
| 12 || GetUserNickname
|-
| 13 || GetUserProfileImage
|-
| 100 || PrepareAsync
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || ScanServersAsync
|-
| 201 || ListServers
|-
| 210 || ConnectByServerIdAsync
|-
| 300 || GetStorageShortfall
|-
| 301 || GetTotalTransferInfo
|-
| 302 || GetImmigrantUid
|-
| 310 || GetCurrentTransferInfo
|-
| 311 || GetCurrentRelatedApplications
|-
| 320 || TransferNextAsync
|-
| 350 || SuspendAsync
|-
| 400 || CompleteAsync
|-
| 500 || Abort
|-
| 999 || DebugSynchronizeStateInFinalizationAsync
|}

== IAsyncContext ==
This is "nn::migration::detail::IAsyncContext".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetSystemEvent
|-
| 1 || Cancel
|-
| 2 || HasDone
|-
| 3 || GetResult
|}

== IAsyncSaveDataMigrationPolicyInfoContext ==
This is "nn::migration::detail::IAsyncSaveDataMigrationPolicyInfoContext".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetSystemEvent
|-
| 1 || Cancel
|-
| 2 || HasDone
|-
| 3 || GetResult
|-
| 100 || GetSaveDataMigrationPolicyInfo
|}

== IServer ==
This is "nn::migration::savedata::IServer".

This was added with [7.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetUid
|-
| 1 || [7.0.0-19.0.1] GetApplicationId
|-
| 2 || [[#GetServerProfile_2|GetServerProfile]]
|-
| 3 || [17.0.0+] [[#ListApplicationIds|ListApplicationIds]]
|-
| 100 || [[#PrepareAsync|PrepareAsync]]
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || [[#WaitConnectionAsync|WaitConnectionAsync]]
|-
| 201 || GetClientProfile
|-
| 202 || [20.0.0+] [[#GetClientProductModel|GetClientProductModel]]
|-
| 203 || [20.0.0+] [[#GetTransferEventId|GetTransferEventId]]
|-
| 204 || [22.0.0+]
|-
| 210 || [8.0.0+] [[#WaitAcceptanceAsync|WaitAcceptanceAsync]]
|-
| 220 || [21.0.0+]
|-
| 300 || [[#ProcessTransferAsync|ProcessTransferAsync]]
|-
| 400 || [[#CompleteAsync|CompleteAsync]]
|-
| 500 || [7.0.0-19.0.1] [[#Abort|Abort]]
|-
| 510 || [19.0.0-20.5.0] [[#AbortAsync|AbortAsync]]
|-
| 511 || [21.0.0+] [[#AbortAsync2|AbortAsync2]]
|-
| 998 || [8.0.0+] DebugTryGetState
|-
| 999 || [8.0.0+] [[#DebugWaitStateSynchronizationFinalizedAsync|DebugWaitStateSynchronizationFinalizedAsync]]
|}

=== GetServerProfile ===
Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

=== ListApplicationIds ===
Takes a s32 offset, a type-0x6 output buffer containing an array of [[NCM_services#ApplicationId|ApplicationIds]], returns a s32 total_out.

=== PrepareAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various other functionality, the async task also uses functionality similar to [[#GetSaveDataMigrationPolicyInfoAsync|GetSaveDataMigrationPolicyInfoAsync]], throwing an error if needed.

[20.0.0+] The above policy functionality is no longer present. This now eventually uses network request [[Network|transfer_events/start]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Calls a vfunc, returns 0 if ret is true.
* Handles state cleanup if needed.
* Calls a func. This uses various [[OLSC_services|olsc:s]] functionality.
* Sets the state flag which was used for the above cleanup.
* Calls a func which uses [[NS_services#IManagerForSystemService|IManagerForSystemService]] GetAccountId. The output is unused.
* Calls a vfunc, returns 0 if ret is true.
* Calls a func.
* Handles [[Sockets_services|sockets]]/etc initialization, enters a nifm block.
* Uses network request [[Network|transfer_events/start]]. The output from this func is copied into state.
* Nifm usage ends here. Handles [[Sockets_services|sockets]] cleanup, etc.

=== Cmd102 ===
No input, returns an output bool.

=== WaitConnectionAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Initializes the data used for the AdvertiseData.
* Calls a func which:
** Calls a func which handles [[LDN_services|ldn]] initialization and network creation. SetProtocol is also used with a value from state.
** Calls a func which:
*** Handles setup for the server socket.
*** Uses [[LDN_services|SetAdvertiseData]] with the above AdvertiseData buffer.
*** Waits for a ldn Node to connect, with timeout etc handling.
*** Then [[LDN_services|SetStationAcceptPolicy]] is used with value 3 (WhiteList), and [[LDN_services|AddAcceptFilterEntry]] is used.
** Calls a func which waits for a socket connection (with timeout etc), and handles socket setup for it.
** Uses [[LDN_services|SetAdvertiseData]] with buf/size = 0 (empty AdvertiseData).
** Uses [[LDN_services|SetStationAcceptPolicy]] with value 1 (AlwaysReject).
** Enters a loop waiting for a state field to become value 0x3 (network message [[#Initialize|Initialize]]/[[#Initialize|Initialize2]] handled). Two funcs are called repeatedly in this loop. These essentially receive [[#Messages|messages]] + process them ([[#Data|Data]] messages not allowed), and send the response network message.
** Updates state and returns 0.
* Calls a vfunc. When the ret is true:
** Calls a func, which receives [[#SendClientProfile|SendClientProfile]] and sends the response. Also calls a func to process the received data.
** Receives [[#RequestServerProfile|RequestServerProfile]] and sends the response.
* Otherwise when the vfunc ret is false:
** Calls a func identical to the first network-message func called in the above block, except a different func is called at the end.
** Runs the same [[#RequestServerProfile|RequestServerProfile]] handling as above.
** Calls a func. This calls a func, then receives [[#GetList|GetList]] and sends the response.
** Calls a func. This runs functionality similar to the earlier message-loop, except this waits for the state field to change to !=0x3 (any network message besides [[#Initialize|Initialize]]/[[#Initialize|Initialize2]] handled). The socket is closed, then a func is called which handles [[LDN_services|ldn]] + [[Sockets_services|sockets]] cleanup.
** Calls a func. This essentially calls the network-creation func from earlier, with the input AdvertiseData being the [[#AdvertiseData|Uuid]].
** Calls a func. This receives [[#Suspend|Suspend]] or [[#SynchronizeState|SynchronizeState]] and sends the response.
* Updates a state flag and returns 0.

=== GetClientProductModel ===
Unofficial name.

No input, returns an output u32.

This loads a field from state. This originates from the [[Settings_services#ProductModel|ProductModel]] field in the [[#SendClientProfile|SendClientProfile]] request.

=== GetTransferEventId ===
Unofficial name.

No input, returns an output s64.

This loads the [[#RequestServerProfile|transfer_event_id]] from state, with an error being returned when the value is -1.

=== Cmd204 ===
No input, returns an output [[NCM_services#ApplicationId|ApplicationId]].

This loads a field from state, with 0 being returned and out=0 when this is -1. Otherwise this is then used as an arrayindex to load the data copied to output (equivalent to [[#ListApplicationIds|ListApplicationIds]] with the state field as the offset).

=== WaitAcceptanceAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task essentially (after state validation) just calls a func which handles receiving + responding to a network message ([[#AcceptDecline|AcceptDecline]] or [[#Suspend|Suspend]]).

=== Cmd220 ===
No input, returns a 0x10-byte struct.

This gets the 0x10-byte struct in state, which was received by [[#WaitAcceptanceAsync|WaitAcceptanceAsync]] from [[#AcceptDecline|AcceptDecline]] (originates from [[#DeclineAsync2|DeclineAsync2]]).

=== ProcessTransferAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Verifies that the [[#WaitConnectionAsync|connected]] state flag is set.
* Calls a vfunc. When ret is false, call another vfunc.
* Call the above vfunc again. If the ret is still false, return an error.
* When a state flag is not set, calls a func.
** Calls a func. This receives [[#Suspend|Suspend]] or [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] and sends the response.
** When the output bool from [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] above is true, just return 0.
** Calls the same func as [[#WaitConnectionAsync|WaitConnectionAsync]], which has a message-loop + socket-closing and cleanup.
** Calls the same func as [[#TransferNextAsync|TransferNextAsync]] for using the network request.
** Abort if a state flag is not set.
** Calls the network-creation func from [[#WaitConnectionAsync|WaitConnectionAsync]], with the input AdvertiseData being the [[#AdvertiseData|Uuid]].
* Enters a loop.
** Calls a func.
*** Initializes stack data.
*** Calls a func. This receives [[#Suspend|Suspend]], [[#SynchronizeState|SynchronizeState]], or [[#PrepareTransfer|PrepareTransfer]] and sends the response. Besides handling Suspend afterwards, this also copies a field to output (this is the output s32 mentioned below).
*** Calls a vfunc. When ret is true, cleanup and return 0.
*** Receives [[#TransferNext|TransferNext]] and sends the response.
** Calls a vfunc. When ret is true, return 0.
** If the Result from the above func is within the fs range for ResultDataCorrupted, and the output s32 from the func is not negative:
*** When a state field is less than the above s32, set another state field to that s32.
*** Break from the loop.
** If the above func returned error, break from the loop.

=== CompleteAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* When the [[#WaitConnectionAsync|connected]] state flag is set:
** Calls the same two funcs as [[#DebugWaitStateSynchronizationFinalizedAsync|DebugWaitStateSynchronizationFinalizedAsync]].
** Handles closing the socket (similar to elsewhere).
** Calls the func which handles cleanup for [[LDN_services|ldn]] + [[Sockets_services|sockets]].
** Clears the connected state flag.
* Calls a vfunc, throwing an error when ret is false.
* Calls a func.
* Calls vfuncs, then returns.

=== Abort ===
No input/output.

This does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Runs essentially the same code-block as [[#CompleteAsync|CompleteAsync]] for the connected flag, without the network messages.
* When a vfunc returns true, call a func.
* Calls vfuncs then returns.

=== AbortAsync ===
Unofficial name.

No input, returns an [[#IAsyncContext|IAsyncContext]].

On 19.x the async task is the cmd impl func used by [[#Abort|Abort]].

=== AbortAsync2 ===
Unofficial name.

Takes an input bool, returns an [[#IAsyncContext|IAsyncContext]].

This is roughly the same as [[#AbortAsync|AbortAsync]] except for the additional functionality done by the async task (etc), for when the input bool is set.

The async task does the following in that block when the input bool is set (handling any errors as needed / calling any logging funcs as needed):
* This block also only runs when a vfunc ret is false.
** Calls a func.
*** Calls a func to get a state field, if this is -1 this then just returns 0.
*** Calls a func.
*** Handles [[Sockets_services|sockets]]/etc initialization.
*** Enters a block which uses nifm.
*** Uses network request [[Network|transfer_events/%lld/abort_transfer]].
*** Nifm usage ends here. Handles [[Sockets_services|sockets]] cleanup, etc.
** If the above func returned an error, depending on the Result this may call a func which logs a report with [[PSC_services|srepo]].

=== DebugWaitStateSynchronizationFinalizedAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Calls a func. This receives [[#Suspend|Suspend]] or [[#SynchronizeState|SynchronizeState]], then sends the response.
* Calls a func. This is basically identical to the above func, except a field written to stack is value 5 instead of 4.

== IClient ==
This is "nn::migration::savedata::IClient".

This was added with [7.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [[#GetClientProfile|GetClientProfile]]
|-
| 100 || GetConnectionRequirement
|-
| 101 || [20.0.0+]
|-
| 200 || ScanServersAsync
|-
| 201 || [[#ListServers|ListServers]]
|-
| 210 || [[#ConnectByServerIdAsync|ConnectByServerIdAsync]]
|-
| 220 || [8.0.0+] [[#AcceptAsync|AcceptAsync]]
|-
| 221 || [8.0.0-20.5.0] [[#DeclineAsync|DeclineAsync]]
|-
| 222 || [21.0.0+] [[#DeclineAsync2|DeclineAsync2]]
|-
| 300 || GetStorageShortfall
|-
| 301 || GetTotalTransferInfo
|-
| 302 || GetImmigrantUid
|-
| 303 || GetApplicationId
|-
| 304 || [17.0.0+] [[#ListApplicationIds|ListApplicationIds]]
|-
| 310 || GetCurrentTransferInfo
|-
| 320 || [[#TransferNextAsync|TransferNextAsync]]
|-
| 350 || [[#SuspendAsync|SuspendAsync]]
|-
| 400 || [[#CompleteAsync_2|CompleteAsync]]
|-
| 500 || [7.0.0-19.0.1] [[#Abort_2|Abort]]
|-
| 510 || [19.0.0+] [[#AbortAsync_2|AbortAsync]]
|-
| 996 || [8.0.0+] DebugTryGetState
|-
| 997 || [8.0.0+] [[#DebugSynchronizeStateInFinalization0Async|DebugSynchronizeStateInFinalization0Async]]
|-
| 998 || [8.0.0+] [[#DebugSynchronizeStateInFinalization1Async|DebugSynchronizeStateInFinalization1Async]]
|-
| 999 || [[#DebugSynchronizeStateFinalizedAsync|DebugSynchronizeStateFinalizedAsync]]
|}

=== GetClientProfile ===
Takes a type-0x1A output buffer containing a [[#ClientProfile|ClientProfile]].

=== Cmd101 ===
No input, returns an output bool.

=== ListServers ===
[20.0.0+] The struct size is now 0x130-bytes instead of 0x128-bytes.

=== ConnectByServerIdAsync ===
Takes an input 0x10-byte struct, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls the same olsc func as [[#PrepareAsync|PrepareAsync]].
* ...
* Loops through an array to find an entry matching the 0x10-bytes from {func input param}, returning an error if not found. (entryptr is the located entry once done)
* Calls a vfunc. If ret is false:
** Calls a func with entryptr+0x10, for copying the input 0x10-bytes into state.
** Calls a func with entryptr+0x20, for copying 0x8-bytes from the input into state.
** Calls a func with entryptr+0x10, for copying the input 0x10-bytes into state.
* Calls a func.
** Clears a state flag if needed.
** entryptr = { Calls a func which loops through an array to find an entry matching the 0x10-bytes from input. } An error is returned if not found.
** Copies 0x480-bytes from entryptr+0x10 to stack, which is later passed to the connect-network func below.
** Calls a func which initializes [[Sockets_services|sockets]] + [[LDN_services|ldn]] if needed (Initialize, SetProtocol(state_field), SetOperationMode(1), OpenStation).
** Then various funcs are called for socket setup / connecting to the network.
*** ldn [[LDN_services|Connect]] is used, retrying with timeout as needed.
*** The TCP socket is setup, and the server is connected to with the IP from the relevant ldn [[LDN_services|NodeInfo]] (GetNetworkInfo) for the AccessPoint.
** Calls a func. This checks a bool state flag. Each block calls a logging func, a func specific to this block (same params for both), and if this is the flag==false block the flag is then set.
*** The funcs called from the above flag-block are roughly same. These send a message, handle receiving a message, then send another message + receive a message. For flag==false these are [[#Messages|MessageId]] 0x0/0x1, while for flag==true these are MessageId 0x8/0x9.
** A func is called which copies 0x10-bytes from entryptr+0x10+0x26C into state.
* Clears stack. Calls a func.
* Calls a func. This uses network message [[#SendClientProfile|SendClientProfile]].
* Calls a vfunc.
* When ret is true:
** Calls a func. This uses network message [[#RequestServerProfile|RequestServerProfile]].
** Sets a state flag, then returns 0.
* Otherwise when the vfunc ret is false:
** Calls a func. This is very similar to the func for RequestServerProfile used above.
** Calls a func.
*** Clears stack, and calls a func.
*** Uses network message [[#GetList|GetList]].
*** Calls a func.
** Calls a func. (fs related?)
** Calls a func. This uses network message [[#Leave|Leave]]. Then the socket is closed. Lastly, a func is called which handles closing [[LDN_services|ldn]] (CloseStation, Finalize) and [[Sockets_services|sockets]].
** Calls a func.
** Clears stack. Enters a block which uses nifm.
*** Calls a func.
*** Clears stack.
*** Calls a func to get a state field.
*** Calls a func which uses network request [[Network|transfer_events/%lld/register_destination]].
** Nifm usage ends here.
** Calls a func.
** Calls a func which handles [[Sockets_services|sockets]] cleanup.
** Calls a func. This essentially does ldn setup again / reconnects to the network. The previously mentioned network messages func used after connection is then called here, with the bool flag being previously updated it would now use MessageId 0x8/0x9. State is also updated.
** Calls a func. This uses network message [[#SynchronizeState|SynchronizeState]] with value 1. Afterwards it then calls a vfunc.
** Sets a state flag, then returns 0.

=== AcceptAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does essentially the following:
* Validates that the state flag which was set at the end of [[#ConnectByServerIdAsync|ConnectByServerIdAsync]] is set.
* Sends [[#AcceptDecline|AcceptDecline]], then receives network data.

=== DeclineAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task is the same as [[#AcceptAsync|AcceptAsync]] except for the transferred data, and also does the following after the transfer:
* Closes the socket.
* Calls the func which handles cleanup for [[LDN_services|ldn]] + [[Sockets_services|sockets]].
* Clears the state flag which was set at the end of [[#ConnectByServerIdAsync|ConnectByServerIdAsync]], then returns 0.

=== DeclineAsync2 ===
Unofficial name.

Takes an input 0x10-byte struct, returns an [[#IAsyncContext|IAsyncContext]].

Same as [[#DeclineAsync|DeclineAsync]] except for the transferred data.

=== TransferNextAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls vfuncs.
* Calls various funcs to check state. This includes calling a fs-related func?
* If a state flag is not set, a func is called:
** Uses network message [[#PrepareTransferDisconnect|PrepareTransferDisconnect]].
** If the state fields checked by [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] for header+0x1 match, this just returns.
** Calls the func which handles disconnecting from the network.
** Calls two funcs.
** Calls a func. This handles using network request [[Network|transfer_events/%lld/save_datas/%lld/generate_key_seed_package]] and uses the relevant [[Filesystem_services|fs]] cmds. [[Filesystem_services|ISaveDataTransferManagerWithDivision SetMode]] is also used with value 1. The previously mentioned state flag is then set.
** Calls the func which handles reconnecting to the network.
* Calls a func when a previously loaded state field is 0.
* Calls a func. (fs related?)
* Calls a func which validates the output from an earlier func.
* Logs a report with [[PSC_services|srepo]].
* Uses network message [[#PrepareTransfer|PrepareTransfer]]. Uses [[Filesystem_services|ISaveDataTransferManagerWithDivision SetLocalKeySeedPackage]] with the relevant response data.
* Logs a report with [[PSC_services|srepo]]. "tr_size" is logged by adding two u64 fields from the 0x20-byte struct returned by [[#PrepareTransfer|PrepareTransfer]]: +0x18 and +0x8.
* Calls a func.
* Calls a func for getting state data.
* Calls a func which writes the various input to the output struct. This is then passed to the the following func which is called:
** Calls a func.
** Uses network message [[#TransferNext|TransferNext]].
** Calls a func.
* Logs a report with [[PSC_services|srepo]].
* If the output from two funcs which load state match, calls a func.
* Cleanup, then returns.

=== SuspendAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task essentially just verifies the [[#ConnectByServerIdAsync|connected]] state flag is set, uses network message [[#Suspend|Suspend]], closes the socket, calls the func which closes [[LDN_services|ldn]] + [[Sockets_services|sockets]], then clears the connected state flag.

=== CompleteAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls a vfunc. When the ret is false:
** Throws an error if not [[#ConnectByServerIdAsync|connected]].
** If a state flag is not set, calls the same func as [[#TransferNextAsync|TransferNextAsync]] for generate_key_seed_package.
** Calls the same func as [[#DebugSynchronizeStateInFinalization0Async|DebugSynchronizeStateInFinalization0Async]].
** Calls the same func as [[#DebugSynchronizeStateInFinalization1Async|DebugSynchronizeStateInFinalization1Async]].
** Calls the same func as [[#DebugSynchronizeStateFinalizedAsync|DebugSynchronizeStateFinalizedAsync]].
** Calls a func which handles disconnecting from the network, without using the network message. This also clears the connected state flag.
* Calls the same vfunc as above again, throwing an error if the ret is still false.
* Handles [[Sockets_services|sockets]] initialization.
* Calls a func.
* Enters a block which uses nifm.
* Calls a func which uses network request [[Network|transfer_events/%lld/finish_transfer]].
* Nifm usage ends here.
* Handles cleanup for [[Sockets_services|sockets]].
* When successful at this point it runs the following block:
** Calls a func. (fs related?)
** Calls a func.
** Calls a func, which logs a report with [[PSC_services|srepo]].
** Calls a vfunc.
** Calls a vfunc (with locking before/after).

=== Abort ===
No input/output.

When the [[#ConnectByServerIdAsync|connected]] state flag is set, this runs code similar to [[#SuspendAsync|SuspendAsync]], without the network message. Then various vfuncs are called. Various funcs are also called as needed (fs related?).

=== AbortAsync ===
Unofficial name.

No input, returns an [[#IAsyncContext|IAsyncContext]].

On 19.x the async task is the cmd impl func used by [[#Abort_2|Abort]].

=== DebugSynchronizeStateInFinalization0Async ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls vfuncs and uses network message [[#SynchronizeState|SynchronizeState]] with value 3.

=== DebugSynchronizeStateInFinalization1Async ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls vfuncs and uses network message [[#SynchronizeState|SynchronizeState]] with value 4.

=== DebugSynchronizeStateFinalizedAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls a vfunc and uses network message [[#SynchronizeState|SynchronizeState]] with value 5.

== IServer ==
This is "nn::migration::device::IServer".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [[#GetServerProfile_3|GetServerProfile]]
|-
| 10 ||
|-
| 20 ||
|-
| 21 ||
|-
| 30 ||
|-
| 40 ||
|-
| 50 ||
|-
| 60 || [22.0.0+]
|-
| 100 ||
|-
| 110 ||
|-
| 111 ||
|-
| 120 || [20.0.0-20.5.0]
|-
| 121 || [21.0.0+]
|-
| 130 ||
|-
| 200 ||
|-
| 230 ||
|-
| 290 ||
|-
| 300 ||
|-
| 400 ||
|-
| 510 || [20.0.0-20.5.0]
|-
| 511 || [21.0.0+]
|-
| 900 ||
|}

=== GetServerProfile ===
Unofficial name.

Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

=== Cmd230 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/start]].

=== Cmd510 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/abort_transfer]].

== IClient ==
This is "nn::migration::device::IClient".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 10 ||
|-
| 20 ||
|-
| 30 ||
|-
| 100 ||
|-
| 110 ||
|-
| 111 ||
|-
| 200 ||
|-
| 210 ||
|-
| 220 ||
|-
| 230 ||
|-
| 240 ||
|-
| 250 ||
|-
| 290 ||
|-
| 300 ||
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 340 ||
|-
| 400 ||
|-
| 500 ||
|-
| 610 ||
|-
| 700 ||
|-
| 710 ||
|-
| 720 ||
|}

== IUnknown ==
This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 ||
|-
| 1 ||
|-
| 2 ||
|-
| 3 ||
|-
| 100 ||
|-
| 110 ||
|}

== IUploader ==
This is "nn::migration::device::IUploader".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 90 ||
|-
| 100 || [20.0.0-20.5.0]
|-
| 101 || [21.0.0+]
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 340 ||
|-
| 350 ||
|-
| 360 || [22.0.0+]
|-
| 400 ||
|-
| 500 ||
|-
| 610 || [20.0.0-20.5.0]
|-
| 611 || [21.0.0+]
|-
| 900 ||
|}

=== Cmd100 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/start]].

=== Cmd500 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/finish_upload]].

=== Cmd610 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/abort_upload]].

=== Cmd900 ===
Takes a total of 4-bytes of input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task may call the same network-request func as [[#Cmd500]].

== IDownloader ==
This is "nn::migration::device::IDownloader".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 10 ||
|-
| 20 ||
|-
| 30 ||
|-
| 90 ||
|-
| 100 ||
|-
| 300 ||
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 390 || [21.0.0+]
|-
| 400 ||
|-
| 500 ||
|-
| 610 ||
|-
| 620 ||
|-
| 900 ||
|}

=== Cmd500 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/finish_download]].

=== Cmd900 ===
Takes a total of 4-bytes of input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task may call the same network-request func as [[#Cmd500_2|Cmd500]].

= ServerProfile =
This is a 0x100-byte struct.

It's unknown whether user/savedata/device use the same struct (size is the same for these).

Any data here which is initialized is usually zeros?

= ClientProfile =
This is a 0x100-byte struct.

It's unknown whether user/savedata/device use the same struct (size is the same for these).

This is usually all-zeros with savedata?

= Protocol =
Once connected with [[LDN_services|ldn]], the client node connects to the server with TCP port 441.

== AdvertiseData ==
These sections document the initial [[LDN_services|AdvertiseData]] used by migration.

The salt used with hashing below is the same regardless of the AdvertiseData.

Immediately after a socket connection is setup, the AdvertiseData is set to size=0. Later when the server recreates the network it also sets the AdvertiseData to {0x10-byte Uuid previously used below}.

The Uuid used below is generated with <code>nn::util::GenerateUuid</code>.

=== user ===
Used by nn::migration::user::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || AccountId
|-
| 0x8 || 0x58 || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* AccountId
* ServerProfile
* 0x100-byte salt

=== savedata ===
Used by nn::migration::savedata::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || AccountId
|-
| 0x8 || 0x8 || ApplicationId
|-
| 0x10 || 0x50 || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* AccountId
* ApplicationId
* ServerProfile
* 0x100-bytes salt

[20.0.0+]:
{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Uuid
|-
| 0x10 || 0x8 || AccountId
|-
| 0x18 || 0x8 || ApplicationId
|-
| 0x20 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|-
| 0x24 || 0x4 || Reserved
|-
| 0x28 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x128 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* Uuid
* AccountId
* ApplicationId
* ProductModel
* ServerProfile
* 0x100-bytes salt

=== device ===
Used by nn::migration::device::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Uuid
|-
| 0x10 || 0x40 (0x8*0x8) || Array of u64s with the below count.
|-
| 0x50 || 0x4 || Count for the above array.
|-
| 0x54 || 0xC || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* Uuid
* +0x10 size 0x40-bytes
* +0x50 size 0x4-bytes
* ServerProfile
* 0x100-bytes salt

== Messages ==
Names are unofficial.

Messages sent over the TCP socket start with the following header:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || MessageId
|-
| 0x1 || 0x7 || Reserved
|}

Data specific to each message follows.

Messages are encrypted with AES-128-GCM (excluding the [[#KeyExchange|KeyExchange]] messages). The key is derived during the messsage-handling for KeyExchange. The 0xC-byte nonce is the 0x8-bytes derived by [[#KeyExchange|KeyExchange]], followed by a big-endian u32 counter (starting at 0x0). This counter is incremented each time a message is encrypted/decrypted. The GCM AAD is not used.

The message size must match the expected fixed-size for the MessageId.

Offsets in the below sections are relative to header+0 (for encrypted messages, this is the plaintext payload instead).

Message requests are sent by the client to the server, then (unless noted otherwise) a response with the same MessageId is sent to the client from the server. The first sent request is [[#KeyExchange|KeyExchange]].

For GCM encrypted messages, the encrypted data starts at +0x8, with the 0x10-byte AES-128-GCM MAC tag immediately afterwards. The first 0xC-bytes of plaintext is the nonce (which must match the expected one during decryption), followed by the payload (can be empty).

{| class="wikitable" border="1"
|-
! MessageId (client/server) || Description
|-
| 0x0 || [[#KeyExchange|KeyExchange]]
|-
| 0x1 || [[#Initialize|Initialize]]
|-
| 0x8 || [[#Challenge|Challenge]]
|-
| 0x9 || [[#Initialize|Initialize2]]
|-
| 0x10 || [[#Leave|Leave]]
|-
| 0x80 || [[#Data|Data]]
|-
| 0xFF || [[#Error|Error]]
|}

=== KeyExchange ===
Request:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x8 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|-
| 0x28 || 0x10 || CMAC ([[SPL_services|ComputeCmac]]) over the above 0x20-bytes, followed by 0x20-bytes from state.
|}

Response:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x8 || 0x10 || Ctr for [[SPL_services|ComputeCtr]] with the below data (generated with [[SPL_services|GenerateRandomBytes]]).
|-
| 0x18 || 0x70 || Data encrypted with [[SPL_services|ComputeCtr]].
|-
| 0x88 || 0x10 || CMAC over the above plaintext data ([[SPL_services|ComputeCmac]]).
|}

The plaintext data has the following structure:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x28 || Passphrase for key derivation (generated with [[SPL_services|GenerateRandomBytes]]).
|-
| 0x28 || 0x20 || Must match the random data previously sent by the client.
|-
| 0x48 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|-
| 0x68 || 0x8 || Zeros
|}

The keyslot for spl is setup with: <code>GenerateAesKek(AccessKey, KeySource, Generation, Option=0); LoadAesKey(keyslot, AccessKey, KeySource);</code>

{| class="wikitable" border="1"
|-
! System Version || Generation
|-
| [4.0.0] || 0x0
|-
| [5.0.0-5.1.0] || 0x5
|-
| [6.0.0-6.2.0] || 0x6
|-
| [7.0.0-8.0.0] || 0x8
|-
| [9.0.0] || 0xA
|-
| [9.1.0-12.1.0] || 0xB
|-
| [13.0.0] || 0xD
|-
| [14.0.0] || 0xE
|-
| [15.0.0] || 0xF
|-
| [16.0.0] || 0x10
|-
| [17.0.0+] || 0x11
|}

PBKDF2-HMAC-SHA256 is used with the first 0x28-bytes of the above plaintext as the passphrase, a 0x20-byte salt from fixed global data, iterations=1000, and i=1. The first 0x10-bytes of the output HMAC then used as the AES-128-GCM key for later messages. The following 0x8-bytes is used as the first 0x8-bytes of the nonce.

=== Initialize ===
This request is sent after [[#KeyExchange|KeyExchange]]. The Initialize2 request is sent after [[#Challenge|Challenge]].

Plaintext request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Must match the 0x20-bytes which is used for [[#KeyExchange|KeyExchange]] response_plaintext+0x48.
|}

The plaintext response payload is empty.

When handling the response, the client sets a state flag. The Initialize2 message is the same as Initialize, except that state field isn't updated during response handling.

=== Challenge ===
This is the first request sent after reconnecting to the server, when an existing connection was previously in use.

Plaintext request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|}

Plaintext response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Must match the random data previously sent by the client.
|-
| 0x20 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]]. Copied into state by the client.
|}

=== Leave ===
This is sent by the client prior to closing the socket and temporarily leaving the ldn network.

The plaintext request/response payload are empty.

=== Data ===
This is used by the client to send additional data following the message, likewise by the server in response.

Plaintext payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || Big-endian data chunksize.
|-
| 0x8 || 0x8 || Big-endian data size.
|}

The additional data is encrypted the same as if it were a message without the message-header, in chunks of up to {above chunksize}.

Both fields must be non-zero, and the chunksize must match 0x100000.

The first chunk starts with a header, with the rest being the actual payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || DataMessageId
|-
| 0x1 || 0x7 || Data for the message if any, normally all-zero.
|}

The DataMessageId in the response received by the client must match one of the expected values, which is usually only the value previously sent in the request. The received size must also match the expected value.

{| class="wikitable" border="1"
|-
! DataMessageId (client/server) || Description
|-
| 0x10 || [[#RequestServerProfile|RequestServerProfile]]
|-
| 0x11 || [[#SendClientProfile|SendClientProfile]]
|-
| 0x12 || [[#GetList|GetList]]
|-
| 0x20 || [[#AcceptDecline|AcceptDecline]]
|-
| 0xE0 || [[#PrepareTransferDisconnect|PrepareTransferDisconnect]]
|-
| 0xE1 || [[#PrepareTransfer|PrepareTransfer]]
|-
| 0xE2 || [[#TransferNext|TransferNext]]
|-
| 0xF0 || [[#SynchronizeState|SynchronizeState]]
|-
| 0xFF || [[#Suspend|Suspend]]
|}

==== RequestServerProfile ====
This is sent by the client following the last vfunc call in [[#ConnectByServerIdAsync|ConnectByServerIdAsync]] where the bool ret is checked, with both true/false blocks. This follows [[#SendClientProfile|SendClientProfile]].

The request only contains the header.

Response payload (0x148-byte struct, which has the following layout):

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || Value 0x1.
|-
| 0x1 || 0x7 || Zeros
|-
| 0x8 || 0x4 || SystemVersion (same form as [[#SendClientProfile|SendClientProfile]])
|-
| 0xC || 0x10 || Uuid (from <code>nn::util::GenerateUuid()</code>)
|-
| 0x1C || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x11C || 0x4 || ApplicationIdsCount (arraycount from [[#Cmd1110]])
|-
| 0x120 || 0x8 || ApplicationId
|-
| 0x128 || 0x8 || [[Network|transfer_event_id]] from the [[#PrepareAsync|/start]] request, then used with the remaining network requests.
|-
| 0x130 || 0x4 || Value 0x1.
|-
| 0x134 || 0x10 || Zeros with savedata.
|-
| 0x144 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|}

When the aforementioned vfunc returned true, the client only uses the response data for verifying that various fields match state. Otherwise when false the client uses this data, in which case:
* The ProductModel must be within [[Settings_services#ProductModel|range]] for Nintendo Switch / Nintendo Switch 2.
* Calls the same func as [[#SendClientProfile|SendClientProfile]] with the above SystemVersion and ProductModel, returning an error if false is returned.
* The u8 at +0x0 must match 0x1.
* The Uuid must be non-zero.
* The ApplicationIdsCount must be 0x1-0x800.
* The ApplicationId must match state.
* Copies data into state, etc.

==== SendClientProfile ====
Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x100 || [[#ClientProfile|ClientProfile]]
|-
| 0x100 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|-
| 0x104 || 0x4 || [[System_Version_Title|SystemVersion]]. u32 in the form: <code>(Major<<16) | (Minor<<8) | Micro</code>
|}

The response only contains the header.

When the vfunc ret at the end of [[#WaitConnectionAsync|WaitConnectionAsync]] is true, the server just validates that the first 0x104-bytes of the above request match state. Otherwise when that vfunc ret is false:
* The ProductModel must be within [[Settings_services#ProductModel|range]] for Nintendo Switch / Nintendo Switch 2.
* Calls a func with the request SystemVersion and ProductModel, returning an error if false is returned.
** If <ProductModel is within the range for Nintendo Switch>: return SystemVersion == <SystemVersion value loaded for the server system>.
** Otherwise: return SystemVersion > <min_sysver> && <ProductModel is within the range for Nintendo Switch 2>.
* Then the ClientProfile/ProductModel are copied into state, etc.

==== GetList ====
This is sent by the client following [[#RequestServerProfile|RequestServerProfile]], where the vfunc mentioned there returned false.

The request only contains the header.

Initial response payload, after the header:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x4 || Data size.
|}

The remaining messages contain the data payload with the above size.

This is used for transferring the contents of a fs file (server reads from it, client writes to a file).

With savedata this is an array where each entry is 0x50-bytes, where each entry has the structure (converted from [[Filesystem_services#SaveDataInfo|SaveDataInfo]]):

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || Type: 0 = SaveDataType System, 1 = SaveDataType Account, 2 = SaveDataType Device.
|-
| 0x1 || 0x1 || IsAccountIdValid (whether loading the AccountId was successful when UserId is non-zero)
|-
| 0x4 || 0x4 || Output from sdk func <code>nn::fs::QuerySaveDataRequiredSizeForImport</code> (on NX the input PlatformIdForSaveDataSizeCalculation is 1).
|-
| 0x8 || 0x8 || SaveDataId
|-
| 0x10 || 0x10 || UserId
|-
| 0x20 || 0x8 || AccountId ([[NS_services#IManagerForSystemService|IManagerForSystemService]] GetAccountId with the UserId, when loaded successfully where UserId is set)
|-
| 0x28 || 0x8 || ApplicationId (for System, SystemSaveDataId)
|-
| 0x30 || 0x4 || [[NS_services#IApplicationVersionInterface|LaunchRequiredVersion]] (from GetLaunchRequiredVersion, for Account/Device)
|-
| 0x38 || 0x18 || (only with Account when IsAccountIdValid is set)
|}

[[Filesystem_services|GetSaveDataCommitId]] is also used when initializing the above entry, however the output is unused besides returning the Result on failure.

==== AcceptDecline ====
This is sent by the client via [[#AcceptAsync|AcceptAsync]]/[[#DeclineAsync|DeclineAsync]]/[[#DeclineAsync2|DeclineAsync2]].

Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || 0 = Decline, 1 = Accept.
|}

[21.0.0+]:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Input from [[#DeclineAsync2|DeclineAsync2]] (zeros with Accept).
|}

At +0x1 in the header prior to this request payload, after DataMessageId is now:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x1 || 0x1 || 0 = Decline, 1 = Accept.
|}

The response only contains the header.

==== PrepareTransferDisconnect ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]] if a state flag is not set, prior to temporarily disconnecting from the network for using network request [[Network|transfer_events/%lld/save_datas/%lld/generate_key_seed_package]].

The request only contains the 0x4-byte header. The bool at header+0x1 (after DataMessageId) is set to <code>statefield==other_statefield</code>. This bool indicates whether the previously mentioned network request is used.

The response only contains the 0x4-byte header.

==== PrepareTransfer ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]] (after [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] if using it was enabled).

The request only contains the header, which besides the DataMessageId contains:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x4 || 0x4 || s32, must not be negative.
|}

Response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 ||
|-
| 0x20 || 0x200 || [[Filesystem_services|LocalKeySeedPackage]]
|}

==== TransferNext ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]], after [[#PrepareTransfer|PrepareTransfer]].

The request only contains the header.

Response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || Zeros
|-
| 0x8 || Rest of message || Transfer payload.
|}

With savedata the transfer payload is the output from exporting savedata from [[Filesystem_services|ISaveDataTransferManagerWithDivision]] (see [[#Notes]]), which the client then imports.

==== SynchronizeState ====
The client sends this via [[#ConnectByServerIdAsync|ConnectByServerIdAsync]], [[#CompleteAsync_2|CompleteAsync]], and DebugSynchronizeState*.

Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x4 || See below.
|}

{| class="wikitable" border="1"
|-
! Value || Description
|-
| 1 || Can be used by [[#ConnectByServerIdAsync|ConnectByServerIdAsync]].
|-
| 3 || [[#DebugSynchronizeStateInFinalization0Async|InFinalization0]]
|-
| 4 || [[#DebugSynchronizeStateInFinalization1Async|InFinalization1]]
|-
| 5 || [[#DebugSynchronizeStateFinalizedAsync|Finalized]]
|}

The response only contains the header.

==== Suspend ====
The client sends this via [[#SuspendAsync|SuspendAsync]]

The request only contains the header.

The response only contains the header.

The server returns an error following handling Suspend.

=== Error ===
This can be sent by the server to the client to signal that an error occurred.

Plaintext response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || ErrorType
|}

If a state field is valid, it's used to load a Result from an array, otherwise the Result is determined from the above ErrorType.

= Notes =
Savedata transfer ("nn::migration::savedata::IServer"/"nn::migration::savedata::IClient") requires that accounts are linked to the same network-account. acc:su [[NS_services#IManagerForSystemService|IManagerForSystemService]] GetAccountId is used here. The server stores this Id into state, and also stores it in the [[LDN_services|ldn]] AdvertiseData. The client also verifies the Id in AdvertiseData against the Id from GetAccountId for the account(s) being used, during ScanServersAsync.

[20.0.0+] [[Filesystem_services#ISaveDataTransferManagerWithDivision|ISaveDataTransferManagerWithDivision]] is now used instead of ISaveDataTransferManager. Besides [[Filesystem_services|SetKeySeedPackage]] being used now as needed, [[Filesystem_services|SetLocalKeySeedPackage]] is now used by the relevant functionality in [[#IClient_2|IClient]] TransferNextAsync.

[S2] System Settings now has an additional menu once send-savedata is selected, for selecting whether to send to Nintendo Switch or Nintendo Switch 2. If Switch 2 is selected, and there's a S1 receiving, the S2 will display a message regarding wrong target system. The receiving system also displays an error. Note that savedata for S2-only applications is only listed with the dest-S2 option (S1-applications are also listed).

[[Category:Services]]

Migration services

2026-05-05T01:12:05Z

Yellows8:

Migration is a sysmodule designed for handling the Switch-to-Switch transfer system introduced in firmware [[4.0.0]].

With newer system-versions this sysmodule is only running when [[qlaunch]] is using migration from the relevant transfer menus (see [[Applet_Manager_services#ActivateMigrationService|ActivateMigrationService]]/[[Applet_Manager_services#DeactivateMigrationService|DeactivateMigrationService]]).

= mig:usr =
This is "nn::migration::user::IService".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [19.0.0+]
|-
| 1 || [20.0.0+]
|-
| 2 || [20.0.0+]
|-
| 10 || [7.0.0-19.0.1] TryGetLastUserMigrationInfo ([4.0.0-6.2.0] TryGetLastMigrationInfo)
|-
| 11 || [20.0.0+]
|-
| 100 || [7.0.0+] [[#CreateUserMigrationServer|CreateUserMigrationServer]] ([4.0.0-6.2.0] CreateServer)
|-
| 101 || [7.0.0+] [[#ResumeUserMigrationServer|ResumeUserMigrationServer]] ([4.0.0-6.2.0] ResumeServer)
|-
| 200 || [7.0.0+] [[#CreateUserMigrationClient|CreateUserMigrationClient]] ([4.0.0-6.2.0] CreateClient)
|-
| 201 || [7.0.0+] [[#ResumeUserMigrationClient|ResumeUserMigrationClient]] ([4.0.0-6.2.0] ResumeClient)
|-
| 1001 || [8.0.0-20.5.0] [[#GetSaveDataMigrationPolicyInfoAsync|GetSaveDataMigrationPolicyInfoAsync]]
|-
| 1010 || [7.0.0+] TryGetLastSaveDataMigrationInfo
|-
| 1100 || [7.0.0-19.0.1] [[#CreateSaveDataMigrationServer|CreateSaveDataMigrationServer]]
|-
| 1101 || [7.0.0+] [[#ResumeSaveDataMigrationServer|ResumeSaveDataMigrationServer]]
|-
| 1110 || [17.0.0+]
|-
| 1200 || [7.0.0+] [[#CreateSaveDataMigrationClient|CreateSaveDataMigrationClient]]
|-
| 1201 || [7.0.0+] [[#ResumeSaveDataMigrationClient|ResumeSaveDataMigrationClient]]
|-
| 2001 || [20.0.0+]
|-
| 2010 || [20.0.0+]
|-
| 2100 || [20.0.0+]
|-
| 2110 || [20.0.0+]
|-
| 2200 || [20.0.0+]
|-
| 2210 || [20.0.0+]
|-
| 2220 || [20.0.0+]
|-
| 2221 || [22.0.0+]
|-
| 2230 || [20.0.0+]
|-
| 2231 || [20.0.0+]
|-
| 2232 || [20.0.0+]
|-
| 2233 || [20.0.0+]
|-
| 2234 || [20.0.0+]
|-
| 2250 || [20.0.0+]
|-
| 2260 || [20.0.0+]
|-
| 2270 || [20.0.0+]
|-
| 2280 || [20.0.0+]
|-
| 2300 || [20.0.0+]
|-
| 2310 || [20.0.0+]
|-
| 2400 || [20.0.0+]
|-
| 2420 || [20.0.0+]
|}

== CreateUserMigrationServer ==
Takes a total of 0x18-bytes of input, a type-0x19 input buffer, a TransferMemory handle, returns an [[#IServer]].

== ResumeUserMigrationServer ==
Takes an input u32, a TransferMemory handle, returns an [[#IServer]].

== CreateUserMigrationClient ==
Takes an input u32, a type-0x19 input buffer, a TransferMemory handle, returns an [[#IClient]].

== ResumeUserMigrationClient ==
Takes an input u32, a TransferMemory handle, returns an [[#IClient]].

== GetSaveDataMigrationPolicyInfoAsync ==
Takes an [[NCM_services#ApplicationId|ApplicationId]], returns an [[#IAsyncSaveDataMigrationPolicyInfoContext]].

This is used by [[qlaunch]] before the actual savedata transfer is started.

This starts a network request for [[Network|save_data_migration_policy]].

[20.0.0+] This was stubbed. The network request is no longer done and the various [[#IAsyncSaveDataMigrationPolicyInfoContext|IAsyncSaveDataMigrationPolicyInfoContext]] cmds just return success (besides GetSystemEvent). GetSaveDataMigrationPolicyInfo just returns the data which was set during object creation.

== CreateSaveDataMigrationServer ==
Takes an u32 tmem_size, an [[Account_services|Uid]], an [[NCM_services#ApplicationId|ApplicationId]], a type-0x19 input buffer containing a [[#ServerProfile|ServerProfile]], a TransferMemory handle, returns an [[#IServer_2|IServer]].

== ResumeSaveDataMigrationServer ==
Takes an input u32 [[#Cmd1110|tmem_size]], a TransferMemory handle, returns an [[#IServer_2|IServer]].

== Cmd1110 ==
Takes an u32 tmem_size, an [[Account_services|Uid]], a type-0x19 input buffer containing a [[#ServerProfile|ServerProfile]], a type-0x5 input buffer containing an array of [[NCM_services#ApplicationId|ApplicationIds]], and a TransferMemory handle. Returns an [[#IServer_2|IServer]].

This is identical to [[#CreateSaveDataMigrationServer|CreateSaveDataMigrationServer]] except the input array is passed directly instead of from a single input [[NCM_services#ApplicationId|ApplicationId]].

The tmem_size must be at least 0x504BB0.

== CreateSaveDataMigrationClient ==
Takes an input u32 tmem_size, a type-0x19 input buffer containing a [[#ClientProfile|ClientProfile]], a TransferMemory handle, returns an [[#IClient_2|IClient]].

== ResumeSaveDataMigrationClient ==
Takes an input u32 tmem_size, a TransferMemory handle, returns an [[#IClient_2|IClient]].

== Cmd2100 ==
Takes 4-bytes of input, a type-0x19 input buffer containing a 0x100-byte struct, a handle. Returns an [[#IServer_3|IServer]].

== Cmd2110 ==
Takes 4-bytes of input, a handle. Returns an [[#IServer_3|IServer]].

== Cmd2200 ==
Takes 4-bytes of input, a type-0x19 input buffer containing a 0x100-byte struct, a handle. Returns an [[#IClient_3|IClient]].

On NX this just calls a logging func and returns an error.

== Cmd2210 ==
Takes 4-bytes of input, a handle. Returns an [[#IClient_3|IClient]].

On NX this just calls a logging func and returns an error.

== Cmd2250 ==
Takes a total of 0x18-bytes of input, a handle. Returns an [[#IUnknown|IUnknown]].

== Cmd2260 ==
Takes 4-bytes of input, a handle. Returns an [[#IUnknown|IUnknown]].

== Cmd2280 ==
Takes an input u64, returns an [[#IAsyncContext]].

This starts a network request for [[Network|transfer_events/%lld/rollback]].

== Cmd2300 ==
Takes a total of 0x18-bytes of input, a handle. Returns an [[#IUploader|IUploader]].

== Cmd2310 ==
Takes 4-bytes of input, a handle. Returns an [[#IUploader|IUploader]].

== Cmd2400 ==
Takes a total of 0x10-bytes of input, a handle. Returns an [[#IDownloader|IDownloader]].

== Cmd2420 ==
Takes 4-bytes of input, a handle. Returns an [[#IDownloader|IDownloader]].

== IServer ==
This is "nn::migration::user::IServer".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetUid
|-
| 1 || [[#GetServerProfile|GetServerProfile]]
|-
| 100 || PrepareAsync
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || WaitConnectionAsync
|-
| 201 || GetClientProfile
|-
| 202 || AcceptConnectionAsync
|-
| 203 || DeclineConnectionAsync
|-
| 300 || ProcessTransferAsync
|-
| 400 || CompleteAsync
|-
| 500 || Abort
|}

=== GetServerProfile ===
Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

== IClient ==
This is "nn::migration::user::IClient".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetClientProfile
|-
| 10 || CreateLoginSession
|-
| 11 || GetNetworkServiceAccountId
|-
| 12 || GetUserNickname
|-
| 13 || GetUserProfileImage
|-
| 100 || PrepareAsync
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || ScanServersAsync
|-
| 201 || ListServers
|-
| 210 || ConnectByServerIdAsync
|-
| 300 || GetStorageShortfall
|-
| 301 || GetTotalTransferInfo
|-
| 302 || GetImmigrantUid
|-
| 310 || GetCurrentTransferInfo
|-
| 311 || GetCurrentRelatedApplications
|-
| 320 || TransferNextAsync
|-
| 350 || SuspendAsync
|-
| 400 || CompleteAsync
|-
| 500 || Abort
|-
| 999 || DebugSynchronizeStateInFinalizationAsync
|}

== IAsyncContext ==
This is "nn::migration::detail::IAsyncContext".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetSystemEvent
|-
| 1 || Cancel
|-
| 2 || HasDone
|-
| 3 || GetResult
|}

== IAsyncSaveDataMigrationPolicyInfoContext ==
This is "nn::migration::detail::IAsyncSaveDataMigrationPolicyInfoContext".

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetSystemEvent
|-
| 1 || Cancel
|-
| 2 || HasDone
|-
| 3 || GetResult
|-
| 100 || GetSaveDataMigrationPolicyInfo
|}

== IServer ==
This is "nn::migration::savedata::IServer".

This was added with [7.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || GetUid
|-
| 1 || [7.0.0-19.0.1] GetApplicationId
|-
| 2 || [[#GetServerProfile_2|GetServerProfile]]
|-
| 3 || [17.0.0+] [[#ListApplicationIds|ListApplicationIds]]
|-
| 100 || [[#PrepareAsync|PrepareAsync]]
|-
| 101 || GetConnectionRequirement
|-
| 102 || [20.0.0+]
|-
| 200 || [[#WaitConnectionAsync|WaitConnectionAsync]]
|-
| 201 || GetClientProfile
|-
| 202 || [20.0.0+] [[#GetClientProductModel|GetClientProductModel]]
|-
| 203 || [20.0.0+] [[#GetTransferEventId|GetTransferEventId]]
|-
| 204 || [22.0.0+]
|-
| 210 || [8.0.0+] [[#WaitAcceptanceAsync|WaitAcceptanceAsync]]
|-
| 220 || [21.0.0+]
|-
| 300 || [[#ProcessTransferAsync|ProcessTransferAsync]]
|-
| 400 || [[#CompleteAsync|CompleteAsync]]
|-
| 500 || [7.0.0-19.0.1] [[#Abort|Abort]]
|-
| 510 || [19.0.0-20.5.0] [[#AbortAsync|AbortAsync]]
|-
| 511 || [21.0.0+] [[#AbortAsync2|AbortAsync2]]
|-
| 998 || [8.0.0+] DebugTryGetState
|-
| 999 || [8.0.0+] [[#DebugWaitStateSynchronizationFinalizedAsync|DebugWaitStateSynchronizationFinalizedAsync]]
|}

=== GetServerProfile ===
Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

=== ListApplicationIds ===
Takes a s32 offset, a type-0x6 output buffer containing an array of [[NCM_services#ApplicationId|ApplicationIds]], returns a s32 total_out.

=== PrepareAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various other functionality, the async task also uses functionality similar to [[#GetSaveDataMigrationPolicyInfoAsync|GetSaveDataMigrationPolicyInfoAsync]], throwing an error if needed.

[20.0.0+] The above policy functionality is no longer present. This now eventually uses network request [[Network|transfer_events/start]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Calls a vfunc, returns 0 if ret is true.
* Handles state cleanup if needed.
* Calls a func. This uses various [[OLSC_services|olsc:s]] functionality.
* Sets the state flag which was used for the above cleanup.
* Calls a func which uses [[NS_services#IManagerForSystemService|IManagerForSystemService]] GetAccountId. The output is unused.
* Calls a vfunc, returns 0 if ret is true.
* Calls a func.
* Handles [[Sockets_services|sockets]]/etc initialization, enters a nifm block.
* Uses network request [[Network|transfer_events/start]]. The output from this func is copied into state.
* Nifm usage ends here. Handles [[Sockets_services|sockets]] cleanup, etc.

=== Cmd102 ===
No input, returns an output bool.

=== WaitConnectionAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Initializes the data used for the AdvertiseData.
* Calls a func which:
** Calls a func which handles [[LDN_services|ldn]] initialization and network creation. SetProtocol is also used with a value from state.
** Calls a func which:
*** Handles setup for the server socket.
*** Uses [[LDN_services|SetAdvertiseData]] with the above AdvertiseData buffer.
*** Waits for a ldn Node to connect, with timeout etc handling.
*** Then [[LDN_services|SetStationAcceptPolicy]] is used with value 3 (WhiteList), and [[LDN_services|AddAcceptFilterEntry]] is used.
** Calls a func which waits for a socket connection (with timeout etc), and handles socket setup for it.
** Uses [[LDN_services|SetAdvertiseData]] with buf/size = 0 (empty AdvertiseData).
** Uses [[LDN_services|SetStationAcceptPolicy]] with value 1 (AlwaysReject).
** Enters a loop waiting for a state field to become value 0x3 (network message [[#Initialize|Initialize]]/[[#Initialize|Initialize2]] handled). Two funcs are called repeatedly in this loop. These essentially receive [[#Messages|messages]] + process them ([[#Data|Data]] messages not allowed), and send the response network message.
** Updates state and returns 0.
* Calls a vfunc. When the ret is true:
** Calls a func, which receives [[#SendClientProfile|SendClientProfile]] and sends the response. Also calls a func to process the received data.
** Receives [[#RequestServerProfile|RequestServerProfile]] and sends the response.
* Otherwise when the vfunc ret is false:
** Calls a func identical to the first network-message func called in the above block, except a different func is called at the end.
** Runs the same [[#RequestServerProfile|RequestServerProfile]] handling as above.
** Calls a func. This calls a func, then receives [[#Data|Data]] message 0x12 and sends the response.
** Calls a func. This runs functionality similar to the earlier message-loop, except this waits for the state field to change to !=0x3 (any network message besides [[#Initialize|Initialize]]/[[#Initialize|Initialize2]] handled). The socket is closed, then a func is called which handles [[LDN_services|ldn]] + [[Sockets_services|sockets]] cleanup.
** Calls a func. This essentially calls the network-creation func from earlier, with the input AdvertiseData being the [[#AdvertiseData|Uuid]].
** Calls a func. This receives [[#Suspend|Suspend]] or [[#SynchronizeState|SynchronizeState]] and sends the response.
* Updates a state flag and returns 0.

=== GetClientProductModel ===
Unofficial name.

No input, returns an output u32.

This loads a field from state. This originates from the [[Settings_services#ProductModel|ProductModel]] field in the [[#SendClientProfile|SendClientProfile]] request.

=== GetTransferEventId ===
Unofficial name.

No input, returns an output s64.

This loads the [[#RequestServerProfile|transfer_event_id]] from state, with an error being returned when the value is -1.

=== Cmd204 ===
No input, returns an output [[NCM_services#ApplicationId|ApplicationId]].

This loads a field from state, with 0 being returned and out=0 when this is -1. Otherwise this is then used as an arrayindex to load the data copied to output (equivalent to [[#ListApplicationIds|ListApplicationIds]] with the state field as the offset).

=== WaitAcceptanceAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task essentially (after state validation) just calls a func which handles receiving + responding to a network message ([[#AcceptDecline|AcceptDecline]] or [[#Suspend|Suspend]]).

=== Cmd220 ===
No input, returns a 0x10-byte struct.

This gets the 0x10-byte struct in state, which was received by [[#WaitAcceptanceAsync|WaitAcceptanceAsync]] from [[#AcceptDecline|AcceptDecline]] (originates from [[#DeclineAsync2|DeclineAsync2]]).

=== ProcessTransferAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Verifies that the [[#WaitConnectionAsync|connected]] state flag is set.
* Calls a vfunc. When ret is false, call another vfunc.
* Call the above vfunc again. If the ret is still false, return an error.
* When a state flag is not set, calls a func.
** Calls a func. This receives [[#Suspend|Suspend]] or [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] and sends the response.
** When the output bool from [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] above is true, just return 0.
** Calls the same func as [[#WaitConnectionAsync|WaitConnectionAsync]], which has a message-loop + socket-closing and cleanup.
** Calls the same func as [[#TransferNextAsync|TransferNextAsync]] for using the network request.
** Abort if a state flag is not set.
** Calls the network-creation func from [[#WaitConnectionAsync|WaitConnectionAsync]], with the input AdvertiseData being the [[#AdvertiseData|Uuid]].
* Enters a loop.
** Calls a func.
*** Initializes stack data.
*** Calls a func. This receives [[#Suspend|Suspend]], [[#SynchronizeState|SynchronizeState]], or [[#PrepareTransfer|PrepareTransfer]] and sends the response. Besides handling Suspend afterwards, this also copies a field to output (this is the output s32 mentioned below).
*** Calls a vfunc. When ret is true, cleanup and return 0.
*** Receives [[#TransferNext|TransferNext]] and sends the response.
** Calls a vfunc. When ret is true, return 0.
** If the Result from the above func is within the fs range for ResultDataCorrupted, and the output s32 from the func is not negative:
*** When a state field is less than the above s32, set another state field to that s32.
*** Break from the loop.
** If the above func returned error, break from the loop.

=== CompleteAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* When the [[#WaitConnectionAsync|connected]] state flag is set:
** Calls the same two funcs as [[#DebugWaitStateSynchronizationFinalizedAsync|DebugWaitStateSynchronizationFinalizedAsync]].
** Handles closing the socket (similar to elsewhere).
** Calls the func which handles cleanup for [[LDN_services|ldn]] + [[Sockets_services|sockets]].
** Clears the connected state flag.
* Calls a vfunc, throwing an error when ret is false.
* Calls a func.
* Calls vfuncs, then returns.

=== Abort ===
No input/output.

This does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Runs essentially the same code-block as [[#CompleteAsync|CompleteAsync]] for the connected flag, without the network messages.
* When a vfunc returns true, call a func.
* Calls vfuncs then returns.

=== AbortAsync ===
Unofficial name.

No input, returns an [[#IAsyncContext|IAsyncContext]].

On 19.x the async task is the cmd impl func used by [[#Abort|Abort]].

=== AbortAsync2 ===
Unofficial name.

Takes an input bool, returns an [[#IAsyncContext|IAsyncContext]].

This is roughly the same as [[#AbortAsync|AbortAsync]] except for the additional functionality done by the async task (etc), for when the input bool is set.

The async task does the following in that block when the input bool is set (handling any errors as needed / calling any logging funcs as needed):
* This block also only runs when a vfunc ret is false.
** Calls a func.
*** Calls a func to get a state field, if this is -1 this then just returns 0.
*** Calls a func.
*** Handles [[Sockets_services|sockets]]/etc initialization.
*** Enters a block which uses nifm.
*** Uses network request [[Network|transfer_events/%lld/abort_transfer]].
*** Nifm usage ends here. Handles [[Sockets_services|sockets]] cleanup, etc.
** If the above func returned an error, depending on the Result this may call a func which logs a report with [[PSC_services|srepo]].

=== DebugWaitStateSynchronizationFinalizedAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task does the following (handling any errors as needed / calling any logging funcs as needed):
* ...
* Calls a func. This receives [[#Suspend|Suspend]] or [[#SynchronizeState|SynchronizeState]], then sends the response.
* Calls a func. This is basically identical to the above func, except a field written to stack is value 5 instead of 4.

== IClient ==
This is "nn::migration::savedata::IClient".

This was added with [7.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [[#GetClientProfile|GetClientProfile]]
|-
| 100 || GetConnectionRequirement
|-
| 101 || [20.0.0+]
|-
| 200 || ScanServersAsync
|-
| 201 || [[#ListServers|ListServers]]
|-
| 210 || [[#ConnectByServerIdAsync|ConnectByServerIdAsync]]
|-
| 220 || [8.0.0+] [[#AcceptAsync|AcceptAsync]]
|-
| 221 || [8.0.0-20.5.0] [[#DeclineAsync|DeclineAsync]]
|-
| 222 || [21.0.0+] [[#DeclineAsync2|DeclineAsync2]]
|-
| 300 || GetStorageShortfall
|-
| 301 || GetTotalTransferInfo
|-
| 302 || GetImmigrantUid
|-
| 303 || GetApplicationId
|-
| 304 || [17.0.0+] [[#ListApplicationIds|ListApplicationIds]]
|-
| 310 || GetCurrentTransferInfo
|-
| 320 || [[#TransferNextAsync|TransferNextAsync]]
|-
| 350 || [[#SuspendAsync|SuspendAsync]]
|-
| 400 || [[#CompleteAsync_2|CompleteAsync]]
|-
| 500 || [7.0.0-19.0.1] [[#Abort_2|Abort]]
|-
| 510 || [19.0.0+] [[#AbortAsync_2|AbortAsync]]
|-
| 996 || [8.0.0+] DebugTryGetState
|-
| 997 || [8.0.0+] [[#DebugSynchronizeStateInFinalization0Async|DebugSynchronizeStateInFinalization0Async]]
|-
| 998 || [8.0.0+] [[#DebugSynchronizeStateInFinalization1Async|DebugSynchronizeStateInFinalization1Async]]
|-
| 999 || [[#DebugSynchronizeStateFinalizedAsync|DebugSynchronizeStateFinalizedAsync]]
|}

=== GetClientProfile ===
Takes a type-0x1A output buffer containing a [[#ClientProfile|ClientProfile]].

=== Cmd101 ===
No input, returns an output bool.

=== ListServers ===
[20.0.0+] The struct size is now 0x130-bytes instead of 0x128-bytes.

=== ConnectByServerIdAsync ===
Takes an input 0x10-byte struct, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls the same olsc func as [[#PrepareAsync|PrepareAsync]].
* ...
* Loops through an array to find an entry matching the 0x10-bytes from {func input param}, returning an error if not found. (entryptr is the located entry once done)
* Calls a vfunc. If ret is false:
** Calls a func with entryptr+0x10, for copying the input 0x10-bytes into state.
** Calls a func with entryptr+0x20, for copying 0x8-bytes from the input into state.
** Calls a func with entryptr+0x10, for copying the input 0x10-bytes into state.
* Calls a func.
** Clears a state flag if needed.
** entryptr = { Calls a func which loops through an array to find an entry matching the 0x10-bytes from input. } An error is returned if not found.
** Copies 0x480-bytes from entryptr+0x10 to stack, which is later passed to the connect-network func below.
** Calls a func which initializes [[Sockets_services|sockets]] + [[LDN_services|ldn]] if needed (Initialize, SetProtocol(state_field), SetOperationMode(1), OpenStation).
** Then various funcs are called for socket setup / connecting to the network.
*** ldn [[LDN_services|Connect]] is used, retrying with timeout as needed.
*** The TCP socket is setup, and the server is connected to with the IP from the relevant ldn [[LDN_services|NodeInfo]] (GetNetworkInfo) for the AccessPoint.
** Calls a func. This checks a bool state flag. Each block calls a logging func, a func specific to this block (same params for both), and if this is the flag==false block the flag is then set.
*** The funcs called from the above flag-block are roughly same. These send a message, handle receiving a message, then send another message + receive a message. For flag==false these are [[#Messages|MessageId]] 0x0/0x1, while for flag==true these are MessageId 0x8/0x9.
** A func is called which copies 0x10-bytes from entryptr+0x10+0x26C into state.
* Clears stack. Calls a func.
* Calls a func. This uses network message [[#SendClientProfile|SendClientProfile]].
* Calls a vfunc.
* When ret is true:
** Calls a func. This uses network message [[#RequestServerProfile|RequestServerProfile]].
** Sets a state flag, then returns 0.
* Otherwise when the vfunc ret is false:
** Calls a func. This is very similar to the func for RequestServerProfile used above.
** Calls a func.
*** Clears stack, and calls a func.
*** Uses network message [[#Data|DataMessageId]] 0x12.
*** Calls a func.
** Calls a func. (fs related?)
** Calls a func. This uses network message [[#Leave|Leave]]. Then the socket is closed. Lastly, a func is called which handles closing [[LDN_services|ldn]] (CloseStation, Finalize) and [[Sockets_services|sockets]].
** Calls a func.
** Clears stack. Enters a block which uses nifm.
*** Calls a func.
*** Clears stack.
*** Calls a func to get a state field.
*** Calls a func which uses network request [[Network|transfer_events/%lld/register_destination]].
** Nifm usage ends here.
** Calls a func.
** Calls a func which handles [[Sockets_services|sockets]] cleanup.
** Calls a func. This essentially does ldn setup again / reconnects to the network. The previously mentioned network messages func used after connection is then called here, with the bool flag being previously updated it would now use MessageId 0x8/0x9. State is also updated.
** Calls a func. This uses network message [[#SynchronizeState|SynchronizeState]] with value 1. Afterwards it then calls a vfunc.
** Sets a state flag, then returns 0.

=== AcceptAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does essentially the following:
* Validates that the state flag which was set at the end of [[#ConnectByServerIdAsync|ConnectByServerIdAsync]] is set.
* Sends [[#AcceptDecline|AcceptDecline]], then receives network data.

=== DeclineAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task is the same as [[#AcceptAsync|AcceptAsync]] except for the transferred data, and also does the following after the transfer:
* Closes the socket.
* Calls the func which handles cleanup for [[LDN_services|ldn]] + [[Sockets_services|sockets]].
* Clears the state flag which was set at the end of [[#ConnectByServerIdAsync|ConnectByServerIdAsync]], then returns 0.

=== DeclineAsync2 ===
Unofficial name.

Takes an input 0x10-byte struct, returns an [[#IAsyncContext|IAsyncContext]].

Same as [[#DeclineAsync|DeclineAsync]] except for the transferred data.

=== TransferNextAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls vfuncs.
* Calls various funcs to check state. This includes calling a fs-related func?
* If a state flag is not set, a func is called:
** Uses network message [[#PrepareTransferDisconnect|PrepareTransferDisconnect]].
** If the state fields checked by [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] for header+0x1 match, this just returns.
** Calls the func which handles disconnecting from the network.
** Calls two funcs.
** Calls a func. This handles using network request [[Network|transfer_events/%lld/save_datas/%lld/generate_key_seed_package]] and uses the relevant [[Filesystem_services|fs]] cmds. [[Filesystem_services|ISaveDataTransferManagerWithDivision SetMode]] is also used with value 1. The previously mentioned state flag is then set.
** Calls the func which handles reconnecting to the network.
* Calls a func when a previously loaded state field is 0.
* Calls a func. (fs related?)
* Calls a func which validates the output from an earlier func.
* Logs a report with [[PSC_services|srepo]].
* Uses network message [[#PrepareTransfer|PrepareTransfer]]. Uses [[Filesystem_services|ISaveDataTransferManagerWithDivision SetLocalKeySeedPackage]] with the relevant response data.
* Logs a report with [[PSC_services|srepo]]. "tr_size" is logged by adding two u64 fields from the 0x20-byte struct returned by [[#PrepareTransfer|PrepareTransfer]]: +0x18 and +0x8.
* Calls a func.
* Calls a func for getting state data.
* Calls a func which writes the various input to the output struct. This is then passed to the the following func which is called:
** Calls a func.
** Uses network message [[#TransferNext|TransferNext]].
** Calls a func.
* Logs a report with [[PSC_services|srepo]].
* If the output from two funcs which load state match, calls a func.
* Cleanup, then returns.

=== SuspendAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

The async task essentially just verifies the [[#ConnectByServerIdAsync|connected]] state flag is set, uses network message [[#Suspend|Suspend]], closes the socket, calls the func which closes [[LDN_services|ldn]] + [[Sockets_services|sockets]], then clears the connected state flag.

=== CompleteAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

This async task does the following (handling any errors as needed / calling any logging funcs as needed):

* ...
* Calls a vfunc. When the ret is false:
** Throws an error if not [[#ConnectByServerIdAsync|connected]].
** If a state flag is not set, calls the same func as [[#TransferNextAsync|TransferNextAsync]] for generate_key_seed_package.
** Calls the same func as [[#DebugSynchronizeStateInFinalization0Async|DebugSynchronizeStateInFinalization0Async]].
** Calls the same func as [[#DebugSynchronizeStateInFinalization1Async|DebugSynchronizeStateInFinalization1Async]].
** Calls the same func as [[#DebugSynchronizeStateFinalizedAsync|DebugSynchronizeStateFinalizedAsync]].
** Calls a func which handles disconnecting from the network, without using the network message. This also clears the connected state flag.
* Calls the same vfunc as above again, throwing an error if the ret is still false.
* Handles [[Sockets_services|sockets]] initialization.
* Calls a func.
* Enters a block which uses nifm.
* Calls a func which uses network request [[Network|transfer_events/%lld/finish_transfer]].
* Nifm usage ends here.
* Handles cleanup for [[Sockets_services|sockets]].
* When successful at this point it runs the following block:
** Calls a func. (fs related?)
** Calls a func.
** Calls a func, which logs a report with [[PSC_services|srepo]].
** Calls a vfunc.
** Calls a vfunc (with locking before/after).

=== Abort ===
No input/output.

When the [[#ConnectByServerIdAsync|connected]] state flag is set, this runs code similar to [[#SuspendAsync|SuspendAsync]], without the network message. Then various vfuncs are called. Various funcs are also called as needed (fs related?).

=== AbortAsync ===
Unofficial name.

No input, returns an [[#IAsyncContext|IAsyncContext]].

On 19.x the async task is the cmd impl func used by [[#Abort_2|Abort]].

=== DebugSynchronizeStateInFinalization0Async ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls vfuncs and uses network message [[#SynchronizeState|SynchronizeState]] with value 3.

=== DebugSynchronizeStateInFinalization1Async ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls vfuncs and uses network message [[#SynchronizeState|SynchronizeState]] with value 4.

=== DebugSynchronizeStateFinalizedAsync ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides various validation, the async task essentially just calls a func which calls a vfunc and uses network message [[#SynchronizeState|SynchronizeState]] with value 5.

== IServer ==
This is "nn::migration::device::IServer".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 || [[#GetServerProfile_3|GetServerProfile]]
|-
| 10 ||
|-
| 20 ||
|-
| 21 ||
|-
| 30 ||
|-
| 40 ||
|-
| 50 ||
|-
| 60 || [22.0.0+]
|-
| 100 ||
|-
| 110 ||
|-
| 111 ||
|-
| 120 || [20.0.0-20.5.0]
|-
| 121 || [21.0.0+]
|-
| 130 ||
|-
| 200 ||
|-
| 230 ||
|-
| 290 ||
|-
| 300 ||
|-
| 400 ||
|-
| 510 || [20.0.0-20.5.0]
|-
| 511 || [21.0.0+]
|-
| 900 ||
|}

=== GetServerProfile ===
Unofficial name.

Takes a type-0x1A output buffer containing a [[#ServerProfile|ServerProfile]].

=== Cmd230 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/start]].

=== Cmd510 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/abort_transfer]].

== IClient ==
This is "nn::migration::device::IClient".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 10 ||
|-
| 20 ||
|-
| 30 ||
|-
| 100 ||
|-
| 110 ||
|-
| 111 ||
|-
| 200 ||
|-
| 210 ||
|-
| 220 ||
|-
| 230 ||
|-
| 240 ||
|-
| 250 ||
|-
| 290 ||
|-
| 300 ||
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 340 ||
|-
| 400 ||
|-
| 500 ||
|-
| 610 ||
|-
| 700 ||
|-
| 710 ||
|-
| 720 ||
|}

== IUnknown ==
This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 0 ||
|-
| 1 ||
|-
| 2 ||
|-
| 3 ||
|-
| 100 ||
|-
| 110 ||
|}

== IUploader ==
This is "nn::migration::device::IUploader".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 90 ||
|-
| 100 || [20.0.0-20.5.0]
|-
| 101 || [21.0.0+]
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 340 ||
|-
| 350 ||
|-
| 360 || [22.0.0+]
|-
| 400 ||
|-
| 500 ||
|-
| 610 || [20.0.0-20.5.0]
|-
| 611 || [21.0.0+]
|-
| 900 ||
|}

=== Cmd100 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/start]].

=== Cmd500 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/finish_upload]].

=== Cmd610 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/abort_upload]].

=== Cmd900 ===
Takes a total of 4-bytes of input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task may call the same network-request func as [[#Cmd500]].

== IDownloader ==
This is "nn::migration::device::IDownloader".

This was added with [20.0.0+].

{| class="wikitable" border="1"
|-
! Cmd || Name
|-
| 10 ||
|-
| 20 ||
|-
| 30 ||
|-
| 90 ||
|-
| 100 ||
|-
| 300 ||
|-
| 310 ||
|-
| 320 ||
|-
| 330 ||
|-
| 390 || [21.0.0+]
|-
| 400 ||
|-
| 500 ||
|-
| 610 ||
|-
| 620 ||
|-
| 900 ||
|}

=== Cmd500 ===
No input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task uses network request [[Network|transfer_events/%lld/finish_download]].

=== Cmd900 ===
Takes a total of 4-bytes of input, returns an [[#IAsyncContext|IAsyncContext]].

Besides other functionality, this async task may call the same network-request func as [[#Cmd500_2|Cmd500]].

= ServerProfile =
This is a 0x100-byte struct.

It's unknown whether user/savedata/device use the same struct (size is the same for these).

Any data here which is initialized is usually zeros?

= ClientProfile =
This is a 0x100-byte struct.

It's unknown whether user/savedata/device use the same struct (size is the same for these).

This is usually all-zeros with savedata?

= Protocol =
Once connected with [[LDN_services|ldn]], the client node connects to the server with TCP port 441.

== AdvertiseData ==
These sections document the initial [[LDN_services|AdvertiseData]] used by migration.

The salt used with hashing below is the same regardless of the AdvertiseData.

Immediately after a socket connection is setup, the AdvertiseData is set to size=0. Later when the server recreates the network it also sets the AdvertiseData to {0x10-byte Uuid previously used below}.

The Uuid used below is generated with <code>nn::util::GenerateUuid</code>.

=== user ===
Used by nn::migration::user::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || AccountId
|-
| 0x8 || 0x58 || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* AccountId
* ServerProfile
* 0x100-byte salt

=== savedata ===
Used by nn::migration::savedata::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || AccountId
|-
| 0x8 || 0x8 || ApplicationId
|-
| 0x10 || 0x50 || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* AccountId
* ApplicationId
* ServerProfile
* 0x100-bytes salt

[20.0.0+]:
{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Uuid
|-
| 0x10 || 0x8 || AccountId
|-
| 0x18 || 0x8 || ApplicationId
|-
| 0x20 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|-
| 0x24 || 0x4 || Reserved
|-
| 0x28 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x128 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* Uuid
* AccountId
* ApplicationId
* ProductModel
* ServerProfile
* 0x100-bytes salt

=== device ===
Used by nn::migration::device::*.

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Uuid
|-
| 0x10 || 0x40 (0x8*0x8) || Array of u64s with the below count.
|-
| 0x50 || 0x4 || Count for the above array.
|-
| 0x54 || 0xC || Reserved
|-
| 0x60 || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x160 || 0x20 || SHA256 hash
|}

The hash is calculated by using SHA256-update with each field separately, followed by the salt:
* Uuid
* +0x10 size 0x40-bytes
* +0x50 size 0x4-bytes
* ServerProfile
* 0x100-bytes salt

== Messages ==
Names are unofficial.

Messages sent over the TCP socket start with the following header:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || MessageId
|-
| 0x1 || 0x7 || Reserved
|}

Data specific to each message follows.

Messages are encrypted with AES-128-GCM (excluding the [[#KeyExchange|KeyExchange]] messages). The key is derived during the messsage-handling for KeyExchange. The 0xC-byte nonce is the 0x8-bytes derived by [[#KeyExchange|KeyExchange]], followed by a big-endian u32 counter (starting at 0x0). This counter is incremented each time a message is encrypted/decrypted. The GCM AAD is not used.

The message size must match the expected fixed-size for the MessageId.

Offsets in the below sections are relative to header+0 (for encrypted messages, this is the plaintext payload instead).

Message requests are sent by the client to the server, then (unless noted otherwise) a response with the same MessageId is sent to the client from the server. The first sent request is [[#KeyExchange|KeyExchange]].

For GCM encrypted messages, the encrypted data starts at +0x8, with the 0x10-byte AES-128-GCM MAC tag immediately afterwards. The first 0xC-bytes of plaintext is the nonce (which must match the expected one during decryption), followed by the payload (can be empty).

{| class="wikitable" border="1"
|-
! MessageId (client/server) || Description
|-
| 0x0 || [[#KeyExchange|KeyExchange]]
|-
| 0x1 || [[#Initialize|Initialize]]
|-
| 0x8 || [[#Challenge|Challenge]]
|-
| 0x9 || [[#Initialize|Initialize2]]
|-
| 0x10 || [[#Leave|Leave]]
|-
| 0x80 || [[#Data|Data]]
|-
| 0xFF || [[#Error|Error]]
|}

=== KeyExchange ===
Request:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x8 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|-
| 0x28 || 0x10 || CMAC ([[SPL_services|ComputeCmac]]) over the above 0x20-bytes, followed by 0x20-bytes from state.
|}

Response:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x8 || 0x10 || Ctr for [[SPL_services|ComputeCtr]] with the below data (generated with [[SPL_services|GenerateRandomBytes]]).
|-
| 0x18 || 0x70 || Data encrypted with [[SPL_services|ComputeCtr]].
|-
| 0x88 || 0x10 || CMAC over the above plaintext data ([[SPL_services|ComputeCmac]]).
|}

The plaintext data has the following structure:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x28 || Passphrase for key derivation (generated with [[SPL_services|GenerateRandomBytes]]).
|-
| 0x28 || 0x20 || Must match the random data previously sent by the client.
|-
| 0x48 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|-
| 0x68 || 0x8 || Zeros
|}

The keyslot for spl is setup with: <code>GenerateAesKek(AccessKey, KeySource, Generation, Option=0); LoadAesKey(keyslot, AccessKey, KeySource);</code>

{| class="wikitable" border="1"
|-
! System Version || Generation
|-
| [4.0.0] || 0x0
|-
| [5.0.0-5.1.0] || 0x5
|-
| [6.0.0-6.2.0] || 0x6
|-
| [7.0.0-8.0.0] || 0x8
|-
| [9.0.0] || 0xA
|-
| [9.1.0-12.1.0] || 0xB
|-
| [13.0.0] || 0xD
|-
| [14.0.0] || 0xE
|-
| [15.0.0] || 0xF
|-
| [16.0.0] || 0x10
|-
| [17.0.0+] || 0x11
|}

PBKDF2-HMAC-SHA256 is used with the first 0x28-bytes of the above plaintext as the passphrase, a 0x20-byte salt from fixed global data, iterations=1000, and i=1. The first 0x10-bytes of the output HMAC then used as the AES-128-GCM key for later messages. The following 0x8-bytes is used as the first 0x8-bytes of the nonce.

=== Initialize ===
This request is sent after [[#KeyExchange|KeyExchange]]. The Initialize2 request is sent after [[#Challenge|Challenge]].

Plaintext request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Must match the 0x20-bytes which is used for [[#KeyExchange|KeyExchange]] response_plaintext+0x48.
|}

The plaintext response payload is empty.

When handling the response, the client sets a state flag. The Initialize2 message is the same as Initialize, except that state field isn't updated during response handling.

=== Challenge ===
This is the first request sent after reconnecting to the server, when an existing connection was previously in use.

Plaintext request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]].
|}

Plaintext response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 || Must match the random data previously sent by the client.
|-
| 0x20 || 0x20 || Data from [[SPL_services|GenerateRandomBytes]]. Copied into state by the client.
|}

=== Leave ===
This is sent by the client prior to closing the socket and temporarily leaving the ldn network.

The plaintext request/response payload are empty.

=== Data ===
This is used by the client to send additional data following the message, likewise by the server in response.

Plaintext payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || Big-endian data chunksize.
|-
| 0x8 || 0x8 || Big-endian data size.
|}

The additional data is encrypted the same as if it were a message without the message-header, in chunks of up to {above chunksize}.

Both fields must be non-zero, and the chunksize must match 0x100000.

The first chunk starts with a header, with the rest being the actual payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || DataMessageId
|-
| 0x1 || 0x7 || Data for the message if any, normally all-zero.
|}

The DataMessageId in the response received by the client must match one of the expected values, which is usually only the value previously sent in the request. The received size must also match the expected value.

{| class="wikitable" border="1"
|-
! DataMessageId (client/server) || Description
|-
| 0x10 || [[#RequestServerProfile|RequestServerProfile]]
|-
| 0x11 || [[#SendClientProfile|SendClientProfile]]
|-
| 0x12 ||
|-
| 0x20 || [[#AcceptDecline|AcceptDecline]]
|-
| 0xE0 || [[#PrepareTransferDisconnect|PrepareTransferDisconnect]]
|-
| 0xE1 || [[#PrepareTransfer|PrepareTransfer]]
|-
| 0xE2 || [[#TransferNext|TransferNext]]
|-
| 0xF0 || [[#SynchronizeState|SynchronizeState]]
|-
| 0xFF || [[#Suspend|Suspend]]
|}

==== RequestServerProfile ====
This is sent by the client following the last vfunc call in [[#ConnectByServerIdAsync|ConnectByServerIdAsync]] where the bool ret is checked, with both true/false blocks. This follows [[#SendClientProfile|SendClientProfile]].

The request only contains the header.

Response payload (0x148-byte struct, which has the following layout):

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || Value 0x1.
|-
| 0x1 || 0x7 || Zeros
|-
| 0x8 || 0x4 || SystemVersion (same form as [[#SendClientProfile|SendClientProfile]])
|-
| 0xC || 0x10 || Uuid (from <code>nn::util::GenerateUuid()</code>)
|-
| 0x1C || 0x100 || [[#ServerProfile|ServerProfile]]
|-
| 0x11C || 0x4 || ApplicationIdsCount (arraycount from [[#Cmd1110]])
|-
| 0x120 || 0x8 || ApplicationId
|-
| 0x128 || 0x8 || [[Network|transfer_event_id]] from the [[#PrepareAsync|/start]] request, then used with the remaining network requests.
|-
| 0x130 || 0x4 || Value 0x1.
|-
| 0x134 || 0x10 || Zeros with savedata.
|-
| 0x144 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|}

When the aforementioned vfunc returned true, the client only uses the response data for verifying that various fields match state. Otherwise when false the client uses this data, in which case:
* The ProductModel must be within [[Settings_services#ProductModel|range]] for Nintendo Switch / Nintendo Switch 2.
* Calls the same func as [[#SendClientProfile|SendClientProfile]] with the above SystemVersion and ProductModel, returning an error if false is returned.
* The u8 at +0x0 must match 0x1.
* The Uuid must be non-zero.
* The ApplicationIdsCount must be 0x1-0x800.
* The ApplicationId must match state.
* Copies data into state, etc.

==== SendClientProfile ====
Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x100 || [[#ClientProfile|ClientProfile]]
|-
| 0x100 || 0x4 || [[Settings_services#GetProductModel|ProductModel]]
|-
| 0x104 || 0x4 || [[System_Version_Title|SystemVersion]]. u32 in the form: <code>(Major<<16) | (Minor<<8) | Micro</code>
|}

The response only contains the header.

When the vfunc ret at the end of [[#WaitConnectionAsync|WaitConnectionAsync]] is true, the server just validates that the first 0x104-bytes of the above request match state. Otherwise when that vfunc ret is false:
* The ProductModel must be within [[Settings_services#ProductModel|range]] for Nintendo Switch / Nintendo Switch 2.
* Calls a func with the request SystemVersion and ProductModel, returning an error if false is returned.
** If <ProductModel is within the range for Nintendo Switch>: return SystemVersion == <SystemVersion value loaded for the server system>.
** Otherwise: return SystemVersion > <min_sysver> && <ProductModel is within the range for Nintendo Switch 2>.
* Then the ClientProfile/ProductModel are copied into state, etc.

==== 0x12 ====
This is sent by the client following [[#RequestServerProfile|RequestServerProfile]], where the vfunc mentioned there returned false.

The request only contains the header.

Response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x4 || Data size.
|-
| 0x4 || {Above size} || Data payload.
|}

==== AcceptDecline ====
This is sent by the client via [[#AcceptAsync|AcceptAsync]]/[[#DeclineAsync|DeclineAsync]]/[[#DeclineAsync2|DeclineAsync2]].

Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || 0 = Decline, 1 = Accept.
|}

[21.0.0+]:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x10 || Input from [[#DeclineAsync2|DeclineAsync2]] (zeros with Accept).
|}

At +0x1 in the header prior to this request payload, after DataMessageId is now:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x1 || 0x1 || 0 = Decline, 1 = Accept.
|}

The response only contains the header.

==== PrepareTransferDisconnect ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]] if a state flag is not set, prior to temporarily disconnecting from the network for using network request [[Network|transfer_events/%lld/save_datas/%lld/generate_key_seed_package]].

The request only contains the 0x4-byte header. The bool at header+0x1 (after DataMessageId) is set to <code>statefield==other_statefield</code>. This bool indicates whether the previously mentioned network request is used.

The response only contains the 0x4-byte header.

==== PrepareTransfer ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]] (after [[#PrepareTransferDisconnect|PrepareTransferDisconnect]] if using it was enabled).

The request only contains the header, which besides the DataMessageId contains:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x4 || 0x4 || s32, must not be negative.
|}

Response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x20 ||
|-
| 0x20 || 0x200 || [[Filesystem_services|LocalKeySeedPackage]]
|}

==== TransferNext ====
The client sends this via [[#TransferNextAsync|TransferNextAsync]], after [[#PrepareTransfer|PrepareTransfer]].

The request only contains the header.

Response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x8 || Zeros
|-
| 0x8 || Rest of message || Transfer payload.
|}

With savedata the transfer payload is the output from exporting savedata from [[Filesystem_services|ISaveDataTransferManagerWithDivision]] (see [[#Notes]]), which the client then imports.

==== SynchronizeState ====
The client sends this via [[#ConnectByServerIdAsync|ConnectByServerIdAsync]], [[#CompleteAsync_2|CompleteAsync]], and DebugSynchronizeState*.

Request payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x4 || See below.
|}

{| class="wikitable" border="1"
|-
! Value || Description
|-
| 1 || Can be used by [[#ConnectByServerIdAsync|ConnectByServerIdAsync]].
|-
| 3 || [[#DebugSynchronizeStateInFinalization0Async|InFinalization0]]
|-
| 4 || [[#DebugSynchronizeStateInFinalization1Async|InFinalization1]]
|-
| 5 || [[#DebugSynchronizeStateFinalizedAsync|Finalized]]
|}

The response only contains the header.

==== Suspend ====
The client sends this via [[#SuspendAsync|SuspendAsync]]

The request only contains the header.

The response only contains the header.

The server returns an error following handling Suspend.

=== Error ===
This can be sent by the server to the client to signal that an error occurred.

Plaintext response payload:

{| class="wikitable" border="1"
|-
! Offset || Size || Description
|-
| 0x0 || 0x1 || ErrorType
|}

If a state field is valid, it's used to load a Result from an array, otherwise the Result is determined from the above ErrorType.

= Notes =
Savedata transfer ("nn::migration::savedata::IServer"/"nn::migration::savedata::IClient") requires that accounts are linked to the same network-account. acc:su [[NS_services#IManagerForSystemService|IManagerForSystemService]] GetAccountId is used here. The server stores this Id into state, and also stores it in the [[LDN_services|ldn]] AdvertiseData. The client also verifies the Id in AdvertiseData against the Id from GetAccountId for the account(s) being used, during ScanServersAsync.

[20.0.0+] [[Filesystem_services#ISaveDataTransferManagerWithDivision|ISaveDataTransferManagerWithDivision]] is now used instead of ISaveDataTransferManager. Besides [[Filesystem_services|SetKeySeedPackage]] being used now as needed, [[Filesystem_services|SetLocalKeySeedPackage]] is now used by the relevant functionality in [[#IClient_2|IClient]] TransferNextAsync.

[S2] System Settings now has an additional menu once send-savedata is selected, for selecting whether to send to Nintendo Switch or Nintendo Switch 2. If Switch 2 is selected, and there's a S1 receiving, the S2 will display a message regarding wrong target system. The receiving system also displays an error. Note that savedata for S2-only applications is only listed with the dest-S2 option (S1-applications are also listed).

[[Category:Services]]