Commit Graph
6 Commits
Author SHA1 Message Date
jaap-jan 8a77b7ca68 Say how far a connection has got while it is still being made
ci / build and test (pull_request) Failing after 2m34s
ci / desktop nightly (pull_request) Skipped
ci / api image (pull_request) Skipped
ci / android head (pull_request) Successful in 3m28s
The connecting card set its status string once, when the tab was created, and
never touched it again. Every connection therefore looked identical from the
outside: one three seconds into a key exchange, one waiting out a fifteen-second
timeout against a machine that is asleep, and one that had hung all drew the
same "connecting…". The card now draws the five steps of getting there, each lit
at the moment the handshake reports reaching it, over an amber track that fills
as they finish.

◆ NOTHING ON THE LIST IS INVENTED. Every row changes state because a layer below
it said so, at the instant the thing it names actually began.

That is the whole reason it is worth showing, and it is why most of this commit
is plumbing rather than XAML: there was no progress reporting anywhere in the
stack to hook a step list onto, and a card animating plausible progress would
have been indistinguishable from one that had stopped receiving any.

SshConnectionPhase names four phases and deliberately not more. SSH.NET runs the
entire handshake inside one ConnectAsync and raises exactly one event from the
middle of it — HostKeyReceived, once the key exchange has produced a key to show
— so that event is the only interior moment there is to report. Everything
before it is Reaching and everything after it is Authenticating. A fifth phase
in that assembly would have to be a timer, so there is not one. OpeningShell is
reported by TerminalWorkspace instead, because that is where it happens: the
factory's work ends with an authenticated connection, and asking for a
pseudo-terminal on one is a separate round trip. The SFTP path passes null — a
second connection opened behind an already-open shell has nobody watching a step
list for it.

The card's fifth step, "Starting the terminal", is the renderer wait and lives
in the shell rather than in the SSH assembly, which has never heard of a
renderer. On the first connection after a cold start it is a real wait with a
real failure mode of its own — a missing WebView2 runtime — so a list that began
at "reaching the host" would leave the one wait most likely to hang unnamed.

Amber for the step in flight, and that follows the palette's rule rather than
bending it. Green is what is true and purple is what you can press; a step still
happening is neither, and it is exactly the caveat-worth-reading that amber
exists for. Steps behind it go green as they become true. Nothing animates,
which is the argument TransfersScreen.axaml already makes for its own track,
reaching a screen with far more reason to want a spinner: a spinner is furniture
invented to fill a state nobody measured, and these states are measured, so the
track fills to what has finished and then waits there.

A refusal keeps the step it stopped on, in red, with the ones behind it still
green. That is the half a progress bar could not do, and it is the difference
between "that host is not there" and "that host is there and would not have me"
— a question the reason sentence alone frequently does not settle.

The strip's dot goes amber while a tab is connecting, on both heads. It was
grey, and so is a tab whose shell has exited: the two states in that strip with
the least in common, one worth waiting for and one over. PhoneShell's own
comment already recorded half of this — the dot stopped being green before
anything had answered — and this is the other half.

Progress is raised inline rather than through System.Progress<T>, which captures
whatever synchronisation context it was constructed on and posts to it. That
reads like a convenience and is really a second place the marshalling decision
gets made: silently, differently under a test with no context, and out of order
with respect to the failure that follows a phase. The shell marshals once, in
one handler, through a new optional post parameter on MainWindowViewModel — the
same seam TransfersViewModel already uses, and for the reason its own remark
gives. The three Dispatcher.UIThread.Post calls that predate it are the ones
this suite's comments record as out of reach; they are left alone rather than
swept in here.

Both heads draw the list. They differ in one place: Phone.axaml's mono class
sets a colour and a size along with the family, so the caption rule names its
own family instead of composing the two and asking two rules for one Foreground.
The desktop's mono sets the family alone, which is why ConnectingCard does
compose them. Each head also gains SHOW LOGS beside the button that gives up —
the step list is this attempt and the log is every other one, which is what a
connection taking too long actually raises.

Seven tests, and the two that matter most run against the container rather than
a fake: a real handshake reports its phases in order, and a host-key refusal
never claims to have authenticated. A fake asserting what it was written to
assert would have established nothing about either. The rest cover the tab
advancing while the connection is gated, the step a refusal stops on, and a
phase reported after the user has given up on the tab. 1,861 tests, none
failing.

The Android head's layout is not verified by anything. It compiles, and
compiled bindings mean every new binding path resolves, but that project is not
in DodoSSH.slnx, there is no test project for it and no device here — so unlike
the desktop card, whose shapes the layout harness measures, these rows have not
been drawn. Vertical fit is reasoned, not observed.
2026-08-10 15:47:45 +02:00
jaap-jan 8209f15741 Let a session's transport say what it negotiated
ISshConnection and ISftpSession both carry Cipher now — the server-to-client
algorithm off SSH.NET's own ConnectionInfo, captured once because a rekey is
not an event that library raises — and TerminalWorkspace.GetSessionFacts hands
that plus the host key's algorithm back per session, without ever handing over
the connection itself. Nothing reads either yet; the status bar that will is
the next commit.
2026-08-08 20:54:14 +02:00
jaap-jan 82966af37b Let a connection be reached through a proxy on this machine's loopback
ci / build and test (push) Successful in 2m8s
ci / android head (push) Successful in 3m20s
ci / desktop nightly (push) Successful in 46s
ci / api image (push) Successful in 23s
Step 1 of docs/reaching-a-host-you-cannot-dial.md, and it is not the step that document said it was.

SshConnectionRequest carries an optional SshLoopbackProxy and BuildConnectionInfo hands SSH.NET its proxy
ConnectionInfo when there is one. Nothing passes one yet: the callers are jump hosts and the relay, which
are steps 2 and 3.

◆ THE BRIDGE WAS THE WRONG FIRST STEP, AND BUILDING IT WOULD HAVE BEEN THE MISTAKE THIS DOCUMENT IS ABOUT.
ADR 0004 says the relay's loopback bridge "also provides ProxyJump via a SOCKS5 dynamic forward — one
mechanism, two features", and the plan took that to mean the bridge was the shared foundation. It is not:
ForwardedPortDynamic *is* the listener for a jump host — SSH.NET accepts on it, speaks SOCKS5 on it and
tunnels through the bastion — so nothing is left for a bridge of ours to do on that path. The relay is the
case with no SshClient to hang a forward off, so it is the bridge's only consumer, and the bridge belongs in
the commit that uses it. What the two actually share is one level down and a tenth of the size: being told
to reach a target through a loopback proxy while staying about the target. That is what this is.

Three properties, one test each.

A port and nothing else, so a proxy anywhere but loopback cannot be expressed. The failure that shape rules
out is an open SOCKS proxy on the user's network for the life of a shell, which nothing would report — so it
is made unrepresentable rather than validated, on the same grounds AuthenticationChoice carries a kind.

SOCKS5 rather than a dumb pipe, which is what keeps host key pinning honest. The target's own name and port
stay in the request, travel to the proxy in the CONNECT, and are what the gate pins — so a machine reached
through a bastion is pinned under its own name instead of under 127.0.0.1 on whatever ephemeral port that
day's forward got, which is not an identity at all. A pipe would have meant handing SSH.NET a stand-in and
remembering everywhere else that it was one.

And a proxy that is not listening fails as a connection error rather than as an unknown host key. The gate
turns "no host key seen" into a fingerprint prompt, and a connection that never reached a server has seen
none either; the prompt would offer to fix the wrong thing, with no fingerprint to show.

TWO THINGS THE TESTS MEASURED RATHER THAN ASSUMED, both found by the first run failing.

The target is resolved at the *bastion*, not here — a SOCKS CONNECT names it and the far end looks it up. So
the test asks for localhost:2222, the address inside the container, and the published port this host would
use means nothing there. That is not a quirk of the fixture; it is what ProxyJump means, and it is why an
ssh_config writes the target's internal address beside its jump host. Getting it wrong is a SOCKS "general
failure" that names neither end.

And the test server refuses forwarding. linuxserver/openssh-server ships AllowTcpForwarding no, which a
dynamic forward does not notice — opening one asks the server nothing — so every connection through it is
refused at channel-open and reported as the same general failure. The fixture patches it and HUPs sshd.
There are two sshd_config files in that image and the running server uses /config/sshd/sshd_config; the
first attempt patched /etc/ssh/sshd_config, which is the one a search finds first, changed the text and
nothing else, and left the failure exactly where it was.

VERIFIED. Build clean with no new warnings, 85 tests in Client.Ssh.Tests against the real sshd, and the
solution builds. The proxy test was seen to fail — proxy.Port + 1 in BuildConnectionInfo — and seen green
again. An earlier mutation attempt did not compile, and the log said 85 passing because the run never
started and the previous log was still on disk; the second attempt deletes the log first, which is worth
copying whenever a mutation "passes".

dotnet format reports one pre-existing IDE1006 in DodoSSH.Api/Features/Events/EventsEndpoint.cs, in a
project nothing here touches. Left alone.
2026-08-07 13:48:15 +02:00
jaap-jan 04faef6597 Move files to and from a host over SFTP
M2's file transfer, built bottom-up: an SFTP session on the SSH layer, a
transfer queue in a project of its own, and the two-pane browser the design
asked for replacing the screen that said it did not exist. Remote listings
carry names, sizes, modification times and a real drwxr-xr-x — nothing in this
repository could render a POSIX mode before — and the queue moves one file at a
time with progress, throughput and resume.

The design import assumed this would be an SFTP subsystem channel on
ISshConnection, beside the shell on a transport that is already up. SSH.NET
does not offer that: SftpClient derives from BaseClient and owns its own
transport, and there is no supported way to hand it an SshClient's session. So
file transfer opens a second authenticated connection, and it is named for
that rather than dressed up as a channel — OpenSftpAsync is on
ISftpSessionFactory, not on a connection. The difference is visible to a user:
the host records a second login, and a host whose password is typed each time
asks for it again on this screen. It goes through the same host key gate, the
same pin and the same two refusals a shell does, so a fingerprint approved for
a terminal is approved here and one approved here reaches the other machines
with the next sync. docs/design-import-gaps.md is corrected, and marked as the
one row where what shipped differs from what it predicted.

Nothing is written at its final name until it is complete. Every transfer goes
to a .dodossh-part file beside its destination and is renamed into place at the
end, so an interrupted transfer can never be mistaken for a finished one —
which matters most for what this screen is actually for, which is copying a
build artefact onto a server and then running it. A destination that already
exists is refused outright rather than overwritten: the queue has no way to
ask, and silently replacing a file somebody's process is serving is the worse
of the two failures. The remote pane has DELETE and MKDIR so that refusal is
not a dead end. A test against the container pins the assumption underneath all
of this — that SFTP's rename does not clobber.

Resume works within a run of the application and not across a restart, and the
limit is deliberate rather than unfinished. Nothing records which source wrote
a part file, and resuming one on the strength of its name matching is how a
corrupt artefact gets delivered with nothing reporting a failure; a part file
found at startup is started over. Making it survive a restart needs the
preferences store this client still has not got. The offset a resume starts at
is the part file's own length rather than the transfer's recorded progress: a
cancellation can land between a write completing and the counter moving, and
only one of those two is a fact about the bytes that are there.

The queue and its connection outlive a lock, as shells do. LockAsync already
argues that locking must not destroy work in flight — it is what somebody does
when they walk away from the machine, which is exactly when a long transfer is
most likely to be running — so TransfersViewModel is created once and the vault
is attached on unlock and detached on lock. What locking takes is the host
list, and it has to: those rows carry decrypted secrets.

DodoSSH.Client.Transfer is a new project rather than more of Client.Ssh. The
two answer different questions — one is about reaching a host, the other about
moving bytes and what to do when moving them stops halfway — and this is the
only client project that deliberately touches the local filesystem.

Three defects the tests found, none of which review would have. SftpPath.Name
answered an empty string for the root. NavigateRemoteAsync wrapped itself in
the busy guard, so navigating from inside another command did nothing at all
and the remote pane simply stayed empty after connecting, with no failure
anywhere to explain it. And opening an SFTP session per test made two
handshakes per test — this client learns a host key by being refused — which
pushed the SSH assembly past sshd's MaxStartups and failed a different few
unrelated tests each run; the session is shared through the fixture now, with
the reason written where the next person will hit it.

1004 tests green across 18 projects, 24 of them new: the SFTP subsystem against
the OpenSSH container, the queue against a real temporary directory and a fake
host, and three more layout measurements because a screen this window has never
laid out is a screen never checked.

Not verified: the screen has not been looked at running. The layout harness
measures it at the window's minimum in three shapes, which is the class of
defect that has shipped here before, but reaching it in the application needs
the compose stack, the migrations, the API and a browser sign-in. What is still
absent — the status bar's transfer count, dragging between the panes,
transferring a directory, and sftp over a bastion — is in
docs/design-import-gaps.md.
2026-07-31 11:07:29 +02:00
jaap-jan 5fccd53824 Add the Avalonia app and the xterm renderer, and fix two real bugs
The terminal works end to end. A new integration test drives a real sshd in
a container through a real PTY, the real pump, the real loopback WebSocket
with its token and origin checks, and a ClientWebSocket standing in for the
page: the login banner arrives, typed input round-trips, and `stty size`
reports the 100x30 the session asked for. The only untested link left is
xterm drawing bytes it was handed.

The WebView is de-risked on Windows, which was the plan's largest risk. Not
by assertion: with the app running there is an established TCP connection
from msedgewebview2 to the data plane port, so WebView2 launched, navigated
to the loopback page, executed terminal.js, and completed the WebSocket
handshake against the real token and origin checks. Linux remains unproven
and the package's own release notes now corroborate the concern -- Linux uses
a WPE backend, and it ships a NativeWebDialog described as useful where
embedded WebViews may be unavailable.

Two bugs found by building it, both of which would have shipped:

- ShellStream.Write buffers and needs an explicit Flush. Without one a
  keystroke is accepted, reported as written, and never reaches the remote:
  the terminal displays output perfectly and simply stops responding to
  input. SSH.NET's own WriteLine flushes, which is why the earlier spike
  never hit it. Found by isolating the pump against real SSH and reading
  BytesRead=51 -- banner and prompt through, nothing after.
- The Windows app manifest needs a supportedOS list, or Avalonia's native
  control host fails outright and the terminal never starts.

Also fixed a genuinely flaky test I happened to catch: SyncCursorTests
tampered with the *last* base64url character, whose low bits the decoder
ignores when the input length is not a multiple of three -- so a tampered
cursor sometimes decoded to identical bytes and verified. It failed roughly
one run in thirty, depending on a random key. Now tampers the penultimate
character, which is fully significant at every length; 40 consecutive runs
are clean.

xterm 6.0.0 plus the fit and webgl addons are vendored as UMD bundles rather
than built with npm, so a clean clone needs only the .NET SDK. Provenance
and licences are recorded next to them, along with the UMD global names
terminal.js depends on -- a bundle that switched to ES modules would load
without error and leave Terminal undefined.

The renderer acknowledges output from term.write's completion callback, not
on receipt. Acknowledging early would return flow-control credit for bytes
the screen has not caught up with, which is the one thing the credit window
exists to measure.

TerminalWorkspace moved into DodoSSH.Client.Terminal: it has no Avalonia
dependency, and having it there is what let the end-to-end test exist at all.

404 tests pass, zero warnings on a clean rebuild, format clean.
2026-07-28 22:30:42 +02:00
jaap-jan eb354bcdd9 Add the SSH session layer and the terminal data plane
The throughput harness the plan requires before any UI, plus the SSH
plumbing under it. 94 new tests, no WebView involved.

Credit-based flow control is what makes `yes` survivable. A terminal renders
at 60 Hz at best while a remote produces output as fast as the network
allows, and the difference has to accumulate somewhere or be refused.
Credit is reserved *before* reading, never after: because the pump cannot
read more than the renderer has room for, the coalescing buffer is bounded
by the window rather than by how fast the remote can talk. When credit runs
out the pump stops reading, SSH's own receive window closes, and the remote
sshd blocks -- backpressure to the source with no custom protocol.

Verified by falsification, not just by passing: with the credit gate removed
three tests fail, including the throughput harness's bounded-memory
assertion. Acknowledgements are clamped because they cross into JavaScript,
where a buggy or hostile page could otherwise claim to have rendered a
gigabyte and talk the host into an unbounded read.

Host key trust is enforced by *failing* the connection rather than
prompting inside the handshake. SSH.NET raises verification synchronously,
so consulting the user there would block the handshake on a UI round trip
and deadlock the first time the prompt needed the UI thread. Unknown host
and changed key become distinct exceptions the caller resolves
asynchronously. A mismatch has no retry path at all: a dialog offering to
continue is how users are trained to click through the one warning that
actually indicates interception. A legitimately rebuilt server is handled by
removing the pin in settings, away from the moment of connecting.

The data plane serves the renderer page from the same loopback listener as
the socket, which makes Origin predictable -- always http://127.0.0.1:{port}
-- where a WebView virtual-host mapping would give a different origin per
backend and nothing to validate. The token is substituted at serve time, so
it never touches disk and never appears in a URL. Being clear about what
that buys: not protection from a process running as this user, which can
read our memory anyway, but from a page in the user's browser attempting
WebSocket connections to loopback ports, which is a real and routine thing.

Two bugs the tests caught. The accept loop handled connections serially, so
an upgraded WebSocket parked it inside the receive loop and every later
request went unanswered -- the page's own script among them. The suite hung
rather than failed, which is how I found it. And SHA-1 is unavoidable here:
RFC 6455 mandates it for Sec-WebSocket-Accept, where it authenticates
nothing. Suppressed narrowly with that reasoning; the alternative,
HttpListener.AcceptWebSocketAsync, throws PlatformNotSupportedException off
Windows.
2026-07-28 21:58:55 +02:00