Files
fips/docs/reference/cli-fipsctl.md
Arjen dca938c104 feat(peer): switchover between a peer's transports, with no handshake
A peer reachable over more than one transport keeps one Noise session
and moves its traffic between transports on failure or degradation.
Implements docs/design/fips-multi-path-switchover.md §4-§10 and closes
the two-interface case in #143.

Three inner link messages next to Heartbeat: `0x52 PathProbe` and
`0x53 PathAck`, carrying a probe id, the sender's path id and a
`remote_active` bit, and `0x54 PathClose`, naming the receiver's path
id and a reason. A probe is an ordinary encrypted frame sent on a
candidate transport; the receiver, having decrypted it against the
session found by index, adds the path as `Probing`, marks it `rx_live`
and answers on that same path. The prober's receipt of the ack marks
the path `Live`, `tx_live`, and takes an RTT sample. No handshake, no
key material, no index allocation. Old nodes drop the unknown types at
debug, so a path to one stays `Probing` and never becomes eligible.

The discovery gate changes shape: a live peer beaconing on a transport
we hold no path to it over becomes a path candidate rather than being
skipped, and the heartbeat tick probes it. The active path's first
probe is small — the handshake proved it and seeded its MTU — while a
standby's discovery probes are padded to the link MTU, as is one a
minute on every path, so a medium that passes small frames and drops
large ones never proves itself. A standby the peer never answers on is
given up after eight probes; the active path never is.

Detection is per path and takes each medium's own failure signal: a
carrier edge, an unreachable-on-send (`ENETUNREACH`/`EHOSTUNREACH`), an
interface going away, or two unanswered heartbeats on a path the peer
is also silent on. Any of them marks the path `Suspect` and selection
leaves it at once, because the standby is warm: heartbeats run at
`node.path.active_heartbeat_ms` where either side sends and
`standby_heartbeat_ms` elsewhere, both stretched by the path's own
round trip so a Tor or Nym path is neither flooded nor declared dead
every round trip. A peer holding one live path is not heartbeated here
at all — selection has nothing to move to, and the link heartbeat keeps
its liveness. Soft signals (the peer's `remote_active` flipping away,
silence here while a standby hears the peer) trigger a probe, never
`Suspect`: reading them as a verdict forces both sides onto one path
and loops under a one-way failure.

A node that loses a path tells the peer with a `PathClose` on a
surviving one, so the peer moves at once rather than after its own
timeout. A transport that returns inside the five-minute grace revives
its dead paths as `Probing` with their RTT window and ETX intact.

Selection is measured, not configured: each path scores
`quality_index(etx, min_rtt)`, and traffic moves when the active path
is no longer eligible (mandatory) or when a standby beats it by
`switch_margin` for `switch_dwell_secs` (discretionary). Min RTT over a
window rather than SRTT, because SRTT inflates under load on the path
carrying traffic while an idle standby looks pristine — a ping-pong
generator. A `role: backup` transport carries a peer's traffic only
while no normal path is eligible, and yields outright when one becomes
eligible. `fipsctl path pin` overrides both while its path is eligible.

A switch re-seeds the path MTU from the new path, tightens the
session MTUs and refreshes the MSS ceiling, so the first frames after a
switch are not black-holed. The link record and `addr_to_link` follow
the active path. The link cost the tree sees is held at its pre-switch
value for the dwell, and until the two receiver reports that span the
switch have arrived — the first counts every frame in flight on the old
path as lost and spikes the per-report ETX for one interval, the second
replaces it — so neither a short flap nor that spike ripples mesh-wide
through parent selection or the next-hop order.

Operator surface: `role: backup` on any transport, `node.path.*`
(`switch_margin`, validated finite and at least 1.0, `switch_dwell_secs`,
`min_samples`, `active_heartbeat_ms`, `standby_heartbeat_ms`), and
`fipsctl path show|pin|unpin` over the `path_show`, `path_pin` and
`path_unpin` control commands.

Two chaos scenarios calibrate the defaults and are wired into both
runners: `dual-path-flap` (a raw-Ethernet veth as the cable, the Docker
bridge over UDP as the wifi) and `dual-udp-flap` (two interface-bound
UDP instances). Each flaps one path under iperf and carries detectors
that can fail on a switchover that did not carry traffic — a per-node
ceiling on "Peer promoted to active" (a second is a re-peering), a
one-second ceiling from link-down to the first switch, and a two-second
ceiling on any zero-byte iperf interval run — alongside the
`path_switches` band. Neither has been run to calibrate; the defaults
are chosen, not derived, and the design doc says so.

Refs #143
2026-09-23 11:48:33 -03:00

358 lines
19 KiB
Markdown

# `fipsctl`
Command-line client for the FIPS daemon's control socket.
## Synopsis
```text
fipsctl [-s SOCKET] <subcommand> [args...]
```
## Description
`fipsctl` connects to a running daemon over its control socket
(Unix domain socket on Linux/macOS, TCP loopback on Windows), sends
one JSON request, and pretty-prints the response. Exits with a
non-zero status if the socket cannot be reached, the daemon returns an
error, or the request times out.
`fipsctl keygen` and `fipsctl address` are special cases: they do not
contact the daemon and operate purely on local files.
For the line-delimited JSON wire protocol, see
[control-socket.md](control-socket.md). For the YAML configuration
that defines the socket location, see
[configuration.md](configuration.md).
## Global Options
| Flag | Argument | Description |
| ---- | -------- | ----------- |
| `-s`, `--socket` | `PATH` | Override the control-socket path (Linux/macOS) or TCP port (Windows). |
| `-V` | — | Print the short version, `<version> (rev <git-hash>)`. The `rev` part is omitted when the build could not read a git revision, as in a package built from a git worktree. |
| `--version` | — | Print the long version: short version plus build target triple. |
| `-h`, `--help` | — | Print usage and exit. Per-subcommand help via `fipsctl <subcommand> --help`. |
## Subcommands
### `show <what>`
Read-only queries against the daemon. Each subcommand maps 1:1 to a
control-socket query (see [control-socket.md](control-socket.md)) and
prints the response's `data` object as pretty JSON.
| Subcommand | Control-socket command | Returns |
| ---------- | ---------------------- | ------- |
| `show status` | `show_status` | Node-level status: identity, version, peer/link/session counts, TUN state, recent sparklines. |
| `show peers` | `show_peers` | Authenticated peer list with link IDs, transport addresses, MMP metrics, Noise/rekey state. |
| `show links` | `show_links` | Active links (one per FMP-authenticated peer): direction, state, byte counters. |
| `show tree` | `show_tree` | Spanning-tree state: root, my coordinates, parent, peer declarations. |
| `show sessions` | `show_sessions` | End-to-end FSP sessions: state, traffic counters, session-MMP metrics, path MTU. |
| `show bloom` | `show_bloom` | Bloom-filter state: own filter sequence, leaf dependents, per-peer filter summaries. |
| `show mmp` | `show_mmp` | MMP metrics summary: per-peer link-layer metrics and per-session session-layer metrics. |
| `show cache` | `show_cache` | Coordinate cache: TTL, fill ratio, per-destination coords and path MTU. |
| `show connections` | `show_connections` | Pending handshake connections: state, idle time, resend count. |
| `show transports` | `show_transports` | Transport instances: type, state, MTU, local address, per-transport stats, and — for interface-bound transports — interface presence (`absent` / `binding` / `present`), carrier, absence policy (`required` / `optional`), time in the current phase, and bind/failed-attempt counts. |
| `show routing` | `show_routing` | Routing summary: pending lookups, retry state, forwarding/discovery/error/congestion counters. |
| `show identity-cache` | `show_identity_cache` | Cached `(node_addr → npub)` entries with last-seen timestamps. |
| `show native-flows` | `show_native_flows` | Native datagram API: open and pending flows with their ports, queue depth and age, bound listeners with their backlog, and the `native` counters. |
### `acl <what>`
| Subcommand | Control-socket command | Returns |
| ---------- | ---------------------- | ------- |
| `acl show` | `show_acl` | Loaded peer-ACL state: allow/deny files, effective mode, default decision, entry counts. |
### `stats <what>`
Time-series metrics from the in-process history rings.
| Subcommand | Control-socket command | Description |
| ---------- | ---------------------- | ----------- |
| `stats list` | `show_stats_list` | Enumerate available metrics, their units, and the per-ring retention windows. |
| `stats metrics` | `show_metrics` | Dump current counter values for every protocol metric family (`forwarding`, `discovery`, `tree`, `bloom`, `congestion`, `errors`, `native`). |
| `stats peers` | `show_stats_peers` | List peers tracked in stats history (active or recently active). |
| `stats history <metric> [options]` | `show_stats_history` | Fetch a time-series window for one metric. |
`stats history` options:
| Flag | Argument | Default | Description |
| ---- | -------- | ------- | ----------- |
| `--peer` | `npub` or hostname | *(none)* | Required for per-peer metrics; resolves through `/etc/fips/hosts` if not an npub. |
| `--window` | `<N>s` / `<N>m` / `<N>h` | `10m` | Window duration. |
| `--granularity` | `1s` or `1m` | `1s` | Ring resolution. `1s` uses the fast ring; `1m` uses the slow ring. |
| `--plot` | — | off | Render a Unicode-block sparkline to stdout instead of JSON. |
### `keygen [options]`
Generate a new FIPS identity keypair locally. Does not contact the
daemon.
| Flag | Argument | Default | Description |
| ---- | -------- | ------- | ----------- |
| `-d`, `--dir` | `DIR` | `/usr/local/etc/fips` (macOS, FreeBSD), `/etc/fips` (other Unix), `%APPDATA%\fips` (Windows) | Output directory for `fips.key` and `fips.pub`. Matches the directory the platform's packaging installs config into, which is where the daemon derives the key paths from. |
| `-f`, `--force` | — | off | Overwrite an existing `fips.key`. |
| `-s`, `--stdout` | — | off | Print `nsec` then `npub` to stdout instead of writing files. |
`fips.key` is written with mode `0600` and `fips.pub` with mode `0644`
on Unix. After running `keygen`, set `node.identity.persistent: true`
in `fips.yaml` or the daemon will overwrite the keys on next start.
### `address [identity] [options]`
Print a node's mesh address (`fd00::/8`) and nothing else, so it can be
captured in a shell substitution. Does not contact the daemon, which
makes it usable from an installer or image build where no node is
running.
| Argument | Description |
| -------- | ----------- |
| `identity` | npub (bech32) or hostname from `/etc/fips/hosts`. Omit to use this node's own identity. |
| Flag | Argument | Default | Description |
| ---- | -------- | ------- | ----------- |
| `-k`, `--key` | `PATH` | *(none)* | Derive from this key file (an `nsec`) or public key file (an `npub`). Conflicts with `identity`. |
With neither an `identity` nor `--key`, the address comes from
`fips.key` in the default key directory (the same directory `keygen`
writes to), falling back to `fips.pub` beside it, since `fips.key` is
mode `0600` and an unprivileged run cannot read it.
The address is derived from the public key exactly as the daemon
derives its own: `fd` followed by the first 15 bytes of
SHA-256(pubkey).
### `connect <peer> <address> <transport>`
Tell the daemon to dial a peer over a specific transport.
| Argument | Description |
| -------- | ----------- |
| `peer` | npub (bech32) or hostname from `/etc/fips/hosts`. |
| `address` | Transport endpoint, e.g. `192.168.1.10:2121`, `[2001:db8::1]:2121`, or a Tor onion. FIPS-mesh ULAs (`fd00::/8`) are rejected for the IP-based transports (udp, tcp, ethernet). |
| `transport` | One of `udp`, `tcp`, `tor`, `nym`, `ethernet`. The named transport must be configured and running. |
### `disconnect <peer>`
Tell the daemon to drop a peer link.
| Argument | Description |
| -------- | ----------- |
| `peer` | npub (bech32) or hostname from `/etc/fips/hosts`. |
### `path <what>`
A peer reachable over more than one transport holds one Noise session and a
*path* per transport; traffic moves between paths on failure or degradation
without a handshake. These commands show and override that choice.
| Subcommand | Description |
| ---------- | ----------- |
| `path show <peer>` | Every path to the peer: its transport, address, state (`probing`, `live`, `suspect`, `dead`), whether it is the one this node sends on (`active`) and the one the peer sends on (`remote_active`), role, pin, how long since each direction was last proven, the min/last RTT, sample count, per-path ETX and score. Also the link cost the tree sees and whether a post-switch hold is in force. |
| `path pin <peer> <transport>` | Pin this node's traffic to the peer to one transport, named by its configured instance name (e.g. `cable`) or numeric id. The pin holds while the path is eligible (live, and answering probes); while it is not — suspect, dead, or unproven — selection is measured as if unpinned, and the pin re-applies the moment the path is eligible again, with no margin or dwell. `unpin` clears it. |
| `path unpin <peer>` | Clear the pin; selection is measured again from the next tick. |
`peer` is an npub (bech32) or a hostname from `/etc/fips/hosts`. Selection
between paths is measured, not configured (see `node.path.*` in
[configuration.md](configuration.md)); the pin and a transport's
`role: backup` are the only overrides.
### `probe <target>`
Diagnose whether a mesh endpoint is reachable, in five stages, and
report a per-stage verdict so a partial failure localizes itself.
| Argument | Description |
| -------- | ----------- |
| `target` | npub (bech32) or hostname from `/etc/fips/hosts`. |
| `--json` | Emit the report as JSON instead of human-readable text. |
| `--timeout <secs>` | Client-side ceiling. Defaults to the budget the daemon computed, which scales with its tick interval. |
The stages are:
1. **bloom** — does any peer's announced filter claim the target, and
did a LookupRequest therefore go out? A miss ends the probe here and
is a statement about the mesh's own knowledge: nobody has heard of
this address. Skipped when the coordinates are already cached, and
when the target is a directly connected peer.
2. **discovery** — waiting for a LookupResponse to answer with
coordinates. Each request the node sends gets its own line under the
stage, with the timeout that attempt was given and whether it drew a
reply. Failing here is the opposite finding to a bloom miss: a peer's
filter did claim the address, and nothing answered for it.
3. **path** — the least-common-ancestor walk between the two
coordinates, plus the next hop this node would select. This is a
**local computation, not a traceroute**: no hop beyond the first is
contacted, and the tree distance is an upper bound on the real hop
count because a crosslink cut-through can deliver in fewer hops.
When no coordinates were available the walk is not computed at all:
`path.coords_known` is false and every tree field is null, rather
than a default that would read as a finding about the spanning tree.
4. **session** — a full Noise XK handshake over FSP. Completing it is
genuine end-to-end evidence: our route reached them, their route
reached us, and the remote holds the expected static key.
5. **rtt** — one MMP sender/receiver report exchange, for a real
round-trip time.
![The probe's five stages, their failure reasons, and the bypass that skips
both lookup stages](../design/diagrams/fips-probe-stages.svg)
Exit status is 0 only for an overall verdict of `ok`; `partial`,
`failed` and `cancelled` all exit 1.
**The stage block fills in as the probe runs.** Each stage reports its
verdict at the moment it reaches one, rather than the whole report
arriving at the end, so a slow stage is visible as the stage that is
slow. On a terminal the block is redrawn in place, with a spinner and a
running elapsed on whichever stage is working; piped or redirected, each
row is printed once, when it settles, and the transcript ends up the
same block. A running stage reports only what the daemon has observed —
which requests have gone unanswered so far, whether the handshake is in
flight, how many receiver reports have arrived — and never previews an
outcome it does not have yet. The per-request lines under the discovery
stage carry the configured timeout of each attempt in parentheses, which
is the node's own ladder rather than a measurement.
The elapsed column comes from the daemon's clock throughout: a finished
stage carries its own tick-quantized figure, and the stage still running
carries the report's elapsed less the stages already accounted for.
Nothing in that column is measured client-side.
**Stages that were never attempted get no row.** A failure marks
everything behind it as not reached, and the report says that once, in
the failed row, rather than three more times. Two cases deliberately keep
their rows: a *skipped* stage, because a skip is a result naming why that
stage was unnecessary, and everything after a *failed path* stage,
because the path preview touches nothing and the session can still
succeed where the preview named no next hop.
Below the stage block, the `path:` line renders the whole tree walk on
one line, from this node to the target, through the least common
ancestor, which is emphasised on a terminal. It is the same computed
walk the `ours`, `theirs` and `tree walk` lines describe, read in one
piece.
`--json` is unaffected and still emits exactly one document, when the
probe ends, so a script parsing the report does not have to skip past
progress output.
**What the probe leaves behind.** It tears down a session it opened
itself and never touches one that already existed. Three residues are
deliberate and worth knowing about:
- The coordinate-cache and identity-cache entries a lookup produced are
not evicted. They are TTL-bounded shared read caches, and evicting
them could strand an unrelated flow mid-route.
- The remote's half of a probe-created session persists until its own
idle timeout (default 90s). There is no teardown wire message. In the
window between our removal and its idle purge, any session frame the
remote sends lands here as one unknown-session reject.
- To obtain a round-trip time the probe sends a `CoordsWarmup`, which
starts MMP reporting on the session. On a session the probe does not
own, that reporting continues until the idle purge — the same traffic
any single data packet would cause, and bounded, but a real change to
a session the probe did not create. The report names it under
`cleanup.warmups_sent`.
Running a probe against a production node is safe: the job carries its
own deadline daemon-side, so it cleans up whether or not the client is
still there.
### `profile tick <on|off|status>`
> **Reading the output.** Step durations are wall clock measured across `await`
> points, not CPU time: a step that waits on I/O accrues that wait, and other
> tasks may run inside the span. That is the intended measure for head-of-line
> delay, and it means a large step is not necessarily an expensive one.
> `arm_starvation` is measured directly as the entry time minus the deadline
> the interval scheduled that tick for. It is not derived from
> `tick_entry_gap`, which carries no starvation signal on its own: under a
> steady delay every gap is exactly one tick period.
Start, stop and inspect a capture of the rx-loop tick body. **Present
only when both `fipsctl` and the daemon are built with
`--features profiling`**; the feature is off by default, so a stock
package does not carry this subcommand and a stock daemon reports
`profile_tick_*` as an unknown command.
| Subcommand | Control-socket command | Description |
| ---------- | ---------------------- | ----------- |
| `profile tick on` | `profile_tick_on` | Create the capture file and start recording. Fails if a capture is already running (naming the active file) or if the directory cannot be written. |
| `profile tick off` | `profile_tick_off` | Stop the capture. The writer is woken immediately, drains once more and is joined, so the command returns promptly. Succeeds, reporting nothing active, when no capture is running. |
| `profile tick status` | `profile_tick_status` | Report `idle`, `running`, `stopped_by_cap` or `stopped_by_error`, plus the active path, bytes written, flush interval and byte cap. |
`profile tick on` options:
| Flag | Argument | Default | Description |
| ---- | -------- | ------- | ----------- |
| `--dir` | directory path | `/var/log/fips` | Where to write the capture. Created if absent. Use it to profile a non-root `cargo run`. |
Against a daemon running as root, `--dir` must name an absolute path
under `/var/log/fips`, and a path that resolves outside it through a
symlinked parent is refused. The control socket is reachable by the
`fips` group, which the security model treats as strictly weaker than
root, so a group member cannot steer a root directory creation at an
arbitrary path. A daemon that is not running as root crosses no such
boundary and takes `--dir` as given, which is what keeps a non-root
`cargo run` capture working. Confining a root daemon's captures to a
different log root is not currently supported.
One file is written per capture, named `profile-<UTC timestamp>.tsv`,
with `-1`, `-2` and so on appended if a capture in the same second
already claimed the name. The capture file is created private to its
owner and is never written over an existing file.
It opens with a `#`-prefixed header block (node npub, build version,
platform, configured tick period, flush interval, byte cap, start
time), then a tab-separated column header, then one row per measured
step per flush interval:
```text
ts_unix kind domain name count max total unit
```
`kind` is `step` for a timed span and `gauge` for a sampled scalar, so
a gauge value never lands under a duration column; `unit` names the
unit of `max` and `total` for that row. Every step present in the build
gets a row every interval, including zero-count rows. Gauges cover
ticks per interval, peer count, the wall gap between successive
tick-arm entries, and the arm-starvation delay, which is measured
against the deadline the tick was scheduled for rather than derived
from the gap.
A capture stops itself on reaching 32 MB, appending a `#` line saying
so; `profile tick status` then reports `stopped_by_cap` until the next
`on` or `off` clears it.
## Exit Codes
| Code | Meaning |
| ---- | ------- |
| `0` | Daemon returned `{"status":"ok",...}`. |
| `1` | Argument parse failure, control-socket connection failure, daemon returned `{"status":"error",...}`, or local I/O failure (keygen). The error message is printed to stderr. |
## Environment
| Variable | Description |
| -------- | ----------- |
| `XDG_RUNTIME_DIR` | Used to derive the default control-socket path when `/run/fips` is absent. |
`fipsctl` does not consume `RUST_LOG`; logging is for the daemon.
## Files
| Path | Purpose |
| ---- | ------- |
| `/etc/fips/hosts` | Maps hostnames to npubs for the `connect`, `disconnect`, and `--peer` arguments. See [configuration.md](configuration.md). |
| Control socket (default) | Same resolution as the daemon: `/run/fips/control.sock` if present; then `/var/run/fips/control.sock` on macOS/FreeBSD if present; then `$XDG_RUNTIME_DIR/fips/control.sock`; finally `/tmp/fips-control.sock` (Unix). A privileged macOS daemon bootstraps the private `/var/run/fips` directory. Windows uses TCP `localhost:21210`. |
If you get `Permission denied` connecting to the socket on Linux,
add your user to the `fips` group (`sudo usermod -aG fips $USER`)
and log out and back in.
## See also
- [`fips`](cli-fips.md) — the daemon.
- [`fipstop`](cli-fipstop.md) — live-status TUI.
- [control-socket.md](control-socket.md) — wire protocol.
- [configuration.md](configuration.md) — YAML reference.