dckcandClaude Opus 5.5
f0557d29d6
The switchboard now serves a Cap'n Web Handle on each of its sockets:
public (no loopback or private addresses) and local. A socket's labels
are fixed in config, so holding the socket's fd is holding that handle;
constrain(labels) returns a narrower one, as Flower's Constrain returns
a narrower fd. Labels only accumulate: a missing key matches anything,
and a key both sides set must agree (labels.js, shared by both).
The switchboard enforces the labels; toybox's Egress no longer checks
URLs itself. It opens a session to its one switchboard socket, constrains
the handle to the vat's grant, and forwards through it; a WebSocket
crosses the session as a pair of message streams. A vat narrows its own
grant with env.egress.constrain().
Grants are now labels as JSON. One stored before, a bare host[:port],
reads as {host, port}.
pnpm start and the systemd units give toybox the public handle; the
switchboard unit binds the local one in its own 0700 runtime directory.
The tests give their toybox the local handle to reach an echo server,
and check that a toybox holding only the public one never reaches it.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
35 lines
1.4 KiB
Cap'n Proto
35 lines
1.4 KiB
Cap'n Proto
# switchboard: toybox's only way out, after Flower's switchboard.
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#
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# Each socket is a handle with fixed labels: a WebSocket upgrade starts a
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# Cap'n Web session whose main object is that handle (see switchboard.js).
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# Whoever starts workerd hands the sockets in (-S/-s), so whoever holds a
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# socket's fd holds that handle and no other.
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using Workerd = import "/workerd/workerd.capnp";
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const config :Workerd.Config = (
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services = [
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(name = "main", worker = .switchboard),
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(name = "nowhere", network = (allow = [])),
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(name = "public-net", network = (allow = ["public"], tlsOptions = (trustBrowserCas = true))),
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(name = "local-net", network = (allow = ["local"], tlsOptions = (trustBrowserCas = true))),
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],
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sockets = [
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(name = "public", http = (), service = (name = "main", props = (json = "{\"network\":\"public\"}"))),
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(name = "local", http = (), service = (name = "main", props = (json = "{\"network\":\"local\"}"))),
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],
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);
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const switchboard :Workerd.Worker = (
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compatibilityDate = "2026-10-01",
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modules = [
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(name = "switchboard.js", esModule = embed "switchboard.js"),
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(name = "labels.js", esModule = embed "labels.js"),
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(name = "capnweb", esModule = embed "node_modules/capnweb/dist/index-workers.js"),
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],
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bindings = [
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(name = "PUBLIC", service = "public-net"),
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(name = "LOCAL", service = "local-net"),
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],
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globalOutbound = "nowhere",
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);
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