Jorijn van der Graaf
f18baf2790
The system-bus policies granted net.catcrafts.IMS1 and org.ofono to root and to the account `user`, postmarketOS's default name, so on a unit whose account is called something else dbus denied every Dial from the dialer — nothing in imsd's journal, nothing on screen. A field user found it by trial (alyx report 14, 2026-09-20; ims ledger F14). Let any local account reach both names and have the daemons decide: placing, answering or ending a call needs polkit's net.catcrafts.IMS1.Voice (the active local session; not an ssh login, an inactive session or a system service account). imsd-ofonod asks about its own callers, since its calls reach imsd as root. Reads such as the status and the call list are not gated, and a refusal is logged with the sender; a `--session` run, the development mode without root or polkit, leaves the gate off. The check is ImsdBus, a small GLib module both daemons link; the package depends on polkit. An upgrade restarts both daemons (the previous commit), so the open policy faces the old, ungated daemons only until the apk transaction ends. Tested on the dev phone (KPN) in builds of this series; not every path has run there.
422 lines
26 KiB
Markdown
422 lines
26 KiB
Markdown
<!-- SPDX-License-Identifier: GPL-3.0-only -->
|
||
<!-- SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts® -->
|
||
|
||
# imsd
|
||
|
||
Userspace IMS/VoLTE daemon for mainline Linux phones.
|
||
|
||
Modem firmware on typical mainline-Linux phones will bring up the IMS PDN but
|
||
can't be used for actual call audio. imsd implements the whole IMS client in
|
||
userspace instead: SIP registration with USIM AKA authentication over kernel
|
||
IPsec (ESP), call signalling, and the AMR-WB RTP media plane wired into
|
||
PipeWire so a stock mobile dialer — Plasma Dialer, or GNOME Calls under Phosh
|
||
and GNOME Mobile — can place and receive real VoLTE calls on a commercial
|
||
network.
|
||
|
||
## Status
|
||
|
||
Call-capable, both directions. Outgoing VoLTE calls place, answer, carry
|
||
full-duplex AMR-WB audio, and tear down; incoming calls ring, answer via
|
||
`Accept`, and carry media the same way — driven end-to-end from a stock
|
||
dialer over the frozen D-Bus ABI. Current state:
|
||
|
||
The engine core (`imsd-core`) is a GLib-free, pure-`std` static library whose
|
||
every decision — SIP framing, SDP selection, the AKAv1-MD5 digest, the
|
||
`ip xfrm` command sequence, and the whole call FSM — is unit-tested on a dev
|
||
box with no bus, modem, or phone; several suites pin output byte-for-byte
|
||
against recorded network traffic. GLib/GDBus, sockets, and subprocess control
|
||
live only in the `imsd` daemon shell, apart from imsd-bus, the GLib polkit
|
||
gate it shares with imsd-ofonod.
|
||
|
||
## Architecture
|
||
|
||
C++26 modules, built with Crafter Build. Six build products:
|
||
|
||
- **imsd-core** (static library) — the engine, pure `import std` C++ with no
|
||
GLib and no I/O side effects. Everything here is unit-testable on any dev
|
||
box without a modem, a bus, or a phone; several suites pin output
|
||
byte-for-byte against recorded network traffic.
|
||
- **imsd** (executable) — the daemon shell: GLib main loop, GDBus service,
|
||
sockets, subprocess control (`qmicli`/`mmcli`/`ip`), and the registration
|
||
sequence + run loop that pumps the core.
|
||
- **imsd-bus** (static library) — the polkit gate in front of call control
|
||
(`net.catcrafts.IMS1.Voice`), which imsd and imsd-ofonod both link. GLib,
|
||
so kept outside imsd-core. A translation daemon that runs as root on the
|
||
system bus reaches imsd as root, which polkit always allows, so it gates
|
||
its own callers through this or it is a bypass.
|
||
- **imsd-media** (executable) — the RTP/AMR-WB data plane, spawned once per
|
||
call. Pure `import std` + POSIX, no GLib; links `-ldl` and dlopen's the
|
||
codecs. A separate process for crash isolation and the far-end-hangup
|
||
exit-code contract.
|
||
- **imsd-dialerd** (executable) — the Plasma Mobile integration: a session
|
||
daemon owning `org.kde.telephony.{CallUtils,DeviceUtils,UssdUtils}`,
|
||
bridging them to imsd on the system bus. GDBus translation only, no core.
|
||
It is a separate process because those are per-user *session*-bus names
|
||
that the root system daemon cannot own; built with `-- --product=dialerd`,
|
||
autostarted from an `.desktop` file in place of plasma-dialer's
|
||
`modem-daemon` (whose autostart must be disabled).
|
||
- **imsd-ofonod** (executable) — the GNOME Calls integration, for Phosh and
|
||
GNOME Mobile: a system daemon owning `org.ofono` and presenting imsd as an
|
||
oFono modem, which is the seam GNOME Calls' bundled `ofono` provider plugin
|
||
drives. GDBus translation, no core, plus the imsd-bus gate on its own
|
||
callers; built with `-- --product=ofonod`.
|
||
See [GNOME Calls (Phosh, GNOME Mobile)](#gnome-calls-phosh-gnome-mobile).
|
||
|
||
### Desktop integration
|
||
|
||
imsd itself is desktop-agnostic: everything a dialer needs is on the system
|
||
bus as `net.catcrafts.IMS1`. Each desktop gets a small translation daemon
|
||
speaking whatever backend protocol its dialer already consumes, so the dialer,
|
||
the shell and the call-history/contacts stack all stay unmodified.
|
||
|
||
| Desktop | Daemon | Owns | Consumed by |
|
||
|---|---|---|---|
|
||
| Plasma Mobile | `imsd-dialerd` | `org.kde.telephony.*` (session bus) | plasma-dialer + kde-telephony-daemon, replacing `modem-daemon` |
|
||
| Phosh / GNOME Mobile | `imsd-ofonod` | `org.ofono` (system bus) | GNOME Calls' `ofono` provider plugin |
|
||
|
||
Phosh's own call UI needs nothing extra: it consumes `org.gnome.Calls`, which
|
||
GNOME Calls exports once it has a working origin.
|
||
|
||
### Terminating-network dependency (incoming)
|
||
|
||
A UE only receives a VoLTE call as a SIP INVITE if the network's Terminating
|
||
Access Domain Selection (T-ADS) routes it to the PS/IMS domain rather than
|
||
paging the modem over CS. That requires the IMS registration to advertise
|
||
voice capability — the MMTEL ICSI (`+g.3gpp.icsi-ref=...mmtel`) and
|
||
`+sip.instance` media-feature tags in the REGISTER Contact, which
|
||
`Imsd:Messages` emits. T-ADS may still select CS for reasons outside the
|
||
client's control (operator policy, the modem's own radio-capability
|
||
signalling, a competing registration). When it does, no INVITE reaches imsd;
|
||
that is a network/modem-integration matter, not a daemon defect.
|
||
|
||
## Supported hardware & carriers
|
||
|
||
imsd talks to the modem through ModemManager plus `qmicli` over QRTR (USIM
|
||
AKA via a UIM logical channel), so in practice it currently needs a Qualcomm
|
||
modem on a mainline kernel with working WWAN/MM integration, kernel ESP
|
||
(`ip xfrm`), and PipeWire for audio.
|
||
|
||
Everything below has been verified by community members to be fully workking:
|
||
|
||
| Device | OS | Carrier
|
||
|---|---|---|
|
||
| The Fairphone (Gen. 6) | postmarketOS, Linux 7.1.2 | KPN NL |
|
||
| The Fairphone (Gen. 6) | postmarketOS, Linux 7.1.2 | Telekom Deutschland GER |
|
||
| The Fairphone (Gen. 6) | postmarketOS, Linux 7.1.2 | Phonero |
|
||
| The Fairphone (Gen. 6) | postmarketOS, Linux 7.1.2 | Telia Norge |
|
||
|
||
## Build
|
||
|
||
[Crafter Build](https://forgejo.catcrafts.net/Catcrafts/Crafter.Build) +
|
||
gio-2.0 headers (`glib2` on Arch, `glib-dev` on Alpine).
|
||
|
||
```sh
|
||
crafter-build # bin/imsd-<target>-<march>/imsd (the daemon)
|
||
crafter-build -- --product=media # bin/imsd-media-.../imsd-media (the media leg)
|
||
crafter-build -- --product=dialerd # bin/imsd-dialerd-.../imsd-dialerd (Plasma backend)
|
||
crafter-build -- --product=ofonod # bin/imsd-ofonod-.../imsd-ofonod (GNOME Calls backend)
|
||
crafter-build test # unit tests (Util, Aka, Ipsec, Messages, Engine, Sip, Sdp)
|
||
```
|
||
|
||
### Building with make (distro packaging)
|
||
|
||
For environments without crafter-build, the Makefile mirrors the same clang
|
||
module pipeline: GNU make, clang++ with libc++ and the libc++ std module
|
||
sources (`std.cppm` — package `llvm-runtimes` on Alpine, `libc++` on Arch),
|
||
lld, and gio-2.0 headers.
|
||
|
||
```sh
|
||
make # build/make/{imsd,imsd-media,imsd-dialerd,imsd-ofonod}
|
||
make check # the same 7 unit-test suites
|
||
make install # DESTDIR/PREFIX staged install incl. the packaging/ files
|
||
```
|
||
|
||
`project.cpp` stays the canonical build description; the Makefile tracks it.
|
||
|
||
### Cross-compiling for a phone (aarch64 Alpine/postmarketOS)
|
||
|
||
```sh
|
||
packaging/make-sysroot.sh # one-time: Alpine aarch64 sysroot from the CDN
|
||
crafter-build -- --target=aarch64-alpine-linux-musl \
|
||
--sysroot=$HOME/.cache/imsd/sysroot-aarch64-alpine \
|
||
--march=armv8.6-a+fp16fml+aes+sha3+sm4 --mtune=cortex-a720
|
||
# same flags after `crafter-build test --target=aarch64-alpine-linux-musl`
|
||
# run the suite under qemu-aarch64 against the sysroot
|
||
```
|
||
|
||
## Run (development)
|
||
|
||
```sh
|
||
./bin/imsd-*/imsd --session # own net.catcrafts.IMS1 on the session bus
|
||
busctl --user call net.catcrafts.IMS1 /net/catcrafts/IMS1 net.catcrafts.IMS1 GetStatus
|
||
```
|
||
|
||
On a phone the daemon runs as root on the system bus, where any local
|
||
account may reach it (`packaging/net.catcrafts.IMS1.conf`); placing,
|
||
answering and ending a call is polkit's `net.catcrafts.IMS1.Voice`
|
||
(`packaging/net.catcrafts.IMS1.policy`, checked by imsd and imsd-ofonod
|
||
alike): the active local session — the dialer, whatever the account is
|
||
called — and root, not an ssh login. It is started by `packaging/imsd.service`
|
||
after `packaging/ims-pdn-up.sh` has brought up the ims PDN through
|
||
ModemManager. An apk upgrade restarts `imsd` and `imsd-ofonod` once the
|
||
transaction is done (a call in progress ends), as does adding a package
|
||
again over the daemon an `apk del` left running; the restart resumes the
|
||
registration over its existing SAs, or goes on waiting out a hold the
|
||
network had set. The bring-up never lets the ims PDN become the phone's IPv6
|
||
default route: the PDN's router advertisement is not accepted as a default
|
||
router (`accept_ra_defrtr=0` on the netdev; its prefix and MTU still apply)
|
||
and the P-CSCF gets a host route instead, so on IPv4-only wifi the phone's
|
||
other IPv6 traffic (apk, browsers) is not sent into the IMS walled garden,
|
||
where it would hang. Media peers get a host route per call; anything else
|
||
on the IMS network (its DNS servers, a traceroute target) needs its own
|
||
(`ip -6 route add <addr> dev qmapmux0.0`). The PDN MTU ModemManager reports
|
||
is set on the link. It spawns
|
||
`/usr/libexec/imsd-media` per call. Registration
|
||
resumes an in-kernel IPsec SA when one is present (avoiding the network's
|
||
fresh-SA throttle) and keeps itself alive with a re-REGISTER refresh at half
|
||
the granted lifetime. `packaging/APKBUILD` builds the apk from source via
|
||
the Makefile; `packaging/APKBUILD.binary` + `make-bin-tarball.sh` wrap a
|
||
cross-compiled build into an apk instead.
|
||
|
||
## GNOME Calls (Phosh, GNOME Mobile)
|
||
|
||
`imsd-ofonod` presents imsd on the system bus as an oFono modem — a Manager at
|
||
`/`, one Modem + VoiceCallManager at `/imsd`, and a VoiceCall object per live
|
||
call — which is what GNOME Calls' bundled `ofono` provider plugin drives.
|
||
Calls, Phosh and GNOME Shell run unmodified.
|
||
|
||
`org.ofono` is the seam because it is the only one a third party can
|
||
implement. `org.gnome.Calls.Call` is what Calls *exports* so a shell can
|
||
observe and control a call that already exists (Accept, Hangup, SendDtmf,
|
||
Silence — there is no Dial); Phosh consumes it from Calls. Calls' own backends
|
||
are libpeas provider plugins (`mm`, `ofono`, `sip`, `dummy`) linked against
|
||
private headers that no distro installs.
|
||
|
||
Setup:
|
||
|
||
```sh
|
||
apk add imsd-ofono # enables imsd-ofonod via a systemd preset
|
||
systemctl enable --now imsd-ofonod # hand installs: system service, org.ofono is a system name
|
||
# point Calls at the ofono provider (the package ships this as a gschema
|
||
# override; this is the per-user equivalent)
|
||
gsettings set org.gnome.Calls autoload-plugins "['ofono']"
|
||
```
|
||
|
||
Drop `mm` from `autoload-plugins` rather than adding `ofono` alongside it: the
|
||
ModemManager provider would offer the modem's own CS voice path as a second
|
||
origin, and on a phone whose voice path is imsd that origin carries no audio.
|
||
|
||
Do not run this alongside a real `ofonod` — there is one `org.ofono` name and
|
||
one owner; the unit declares `Conflicts=ofono.service` and the daemon exits if
|
||
it loses the name. Running `imsd-dialerd` at the same time is fine (different
|
||
bus, different consumer).
|
||
|
||
Verified on a Fairphone 6 (postmarketOS, dbus-broker) with GNOME Calls 50.0:
|
||
outgoing and incoming calls with audio both ways, answered and hung up through
|
||
`org.gnome.Calls.Call` — the surface Phosh drives. One dbus-broker detail is
|
||
load-bearing and lives in the policy file: dbus-broker checks a broadcast
|
||
against the sender's send policy for every name the receiver owns, so root
|
||
(imsd) must be allowed `send_destination="org.ofono"` or imsd's call signals
|
||
never reach the daemon.
|
||
|
||
Known gaps, all inherited rather than introduced:
|
||
|
||
- **USSD is refused** with `org.ofono.Error.NotSupported`; the IMS stack has no
|
||
USSD path. It is deliberately not advertised in the modem's `Interfaces`.
|
||
- **No hold, multiparty, transfer or call waiting** — imsd is a single-call
|
||
stack, so those methods return `org.ofono.Error.NotImplemented`.
|
||
- **Per-call caller-ID withholding is refused** rather than silently ignored:
|
||
imsd cannot honour a CLIR request, and failing is safer than dialling with
|
||
the caller ID exposed.
|
||
- **Phosh's emergency-call screen lists nothing.** Not for want of the data:
|
||
`imsd-ofonod` publishes `org.ofono.VoiceCallManager.EmergencyNumbers` (112,
|
||
911, plus `EMERGENCY_NUMBERS`), which is oFono's standard place for it.
|
||
Calls' ofono provider simply never reads it — it makes no `GetProperties`
|
||
call on the VoiceCallManager, and returns NULL for the origin's
|
||
`emergency-numbers`, which is what
|
||
`org.gnome.Calls.EmergencyCalls.GetEmergencyContacts` is built from. (The
|
||
ModemManager provider does read it, via `mm_sim_dup_emergency_numbers()`.)
|
||
An upstream fix would close this. Dialling an emergency number from the
|
||
normal dialpad is unaffected — that reaches imsd's own classifier.
|
||
- DTMF is forwarded to imsd, where `SendDtmf` is still a stub (RFC 4733 is not
|
||
implemented yet) — the same limitation Plasma has.
|
||
- **Restarting `imsd-ofonod` restarts GNOME Calls with it.** When the
|
||
modem's `VoiceCallManager` interface goes away and comes back, Calls 50.0
|
||
adds a new origin but leaves the old origin's `CallAdded` handler connected:
|
||
after one such cycle every call is added twice, after a few the stale handler
|
||
runs on freed memory and Calls dies with SIGBUS in `g_hash_table_lookup`
|
||
(measured on the FP6). Calls-side; an upstream fix belongs in
|
||
`plugins/provider/ofono/calls-ofono-provider.c`. To keep imsd's own
|
||
restarts and registration drops from triggering it, `imsd-ofonod` lists the
|
||
interface permanently: `Online` tracks registration, and `Dial` fails with
|
||
"imsd is not registered" / "imsd is not running" instead. Only `org.ofono`
|
||
vanishing — this daemon restarting — still cycles the origin, and after
|
||
that Calls dials nothing until it restarts, so the unit's `ExecStartPost`
|
||
restarts the Calls daemon of every user running one. Its first start
|
||
since boot leaves a running Calls alone.
|
||
|
||
Development, without a phone or root:
|
||
|
||
```sh
|
||
./bin/imsd-*/imsd --session & # imsd's ABI on the session bus
|
||
./bin/imsd-ofonod-*/imsd-ofonod --session
|
||
busctl --user call org.ofono / org.ofono.Manager GetModems
|
||
# or keep org.ofono on the system bus and imsd on the session bus:
|
||
IMSD_BUS=session imsd-ofonod
|
||
```
|
||
|
||
## Configuration
|
||
|
||
Everything is environment variables. The packaged unit reads
|
||
`/run/imsd.env` (written by `ims-pdn-up.sh`: the connected ims netdev and
|
||
the PDN address ModemManager assigned to it) and
|
||
then `/etc/imsd.env` (your configuration, wins on conflict). Minimum viable
|
||
`/etc/imsd.env`:
|
||
|
||
```sh
|
||
# REQUIRED until P-CSCF discovery from the PDN's PCO is implemented: your
|
||
# carrier's P-CSCF address. Find it in a stock-firmware capture or your
|
||
# carrier's IMS documentation.
|
||
PCSCF=2001:db8::105
|
||
```
|
||
|
||
### imsd
|
||
|
||
| Variable | Default | Meaning |
|
||
|---|---|---|
|
||
| `PCSCF` | *(none — required)* | P-CSCF address; without it registration fails with a clear error |
|
||
| `PCSCF_PORT` | `5060` | unprotected SIP port for the initial REGISTER |
|
||
| `DEV` | `qmapmux0.0` | ims-PDN netdev; the packaged service passes the real one via `/run/imsd.env` |
|
||
| `LOCAL` | *(auto)* | UE address. The packaged service gets the PDN address ModemManager assigned, via `/run/imsd.env` from `ims-pdn-up.sh`; a manual run prefers a global IPv6 on `DEV` that is neither temporary nor `dynamic` (RA-derived), then any non-temporary one, then the first (the kernel's temporary SLAAC address is listed first, and a registration bound to it is lost when the kernel retires it) |
|
||
| `USER_AGENT` | `imsd/<version>` | REGISTER User-Agent. Some networks fingerprint UAs; setting your device's stock build string reproduces the stock modem's registration exactly. Empty omits the header |
|
||
| `STATE_FILE` | `/var/lib/imsd/imsreg.state` (root) / `$XDG_STATE_HOME/imsd/imsreg.state` | persisted registration context for warm resume |
|
||
| `HOLDS_FILE` | `/run/imsd.holds` (root) / `$XDG_RUNTIME_DIR/imsd.holds` (`/tmp/imsd.holds` without a runtime dir) | the waits the network imposed (a `Retry-After`, the refusal schedule) and where that schedule stands, kept across a restart of imsd for the PDN they were set on — not across a reboot; `/dev/null` switches the file off (only a regular file is ever removed; anything else is emptied) |
|
||
| `RESUME` | `auto` | `0` forces a fresh registration (ignores a warm SA) |
|
||
| `REFRESH_INTERVAL` | *(auto)* | keepalive re-REGISTER period in s; default = half the granted expiry, clamped to [120, 1800] |
|
||
| `EALG` | `aes-cbc` | offered ESP cipher (`aes-cbc`, `des-ede3-cbc`, `null`). From the 401's `Security-Server` list imsd selects the highest-preference `ipsec-3gpp` mechanism that matches this offer (RFC 3329 §2.3.1) and takes the SPIs/ports from the entry carrying them (some cores list every mechanism they support and put the SPIs on the one they applied); when no entry matches, the P-CSCF's SPI-carrying entry is installed as listed (`hmac-md5-96`, an absent `ealg` = null) and the journal says so. The line, the selection and the SA parameters are logged at every fresh registration |
|
||
| `SIP_TRANSPORT` | `auto` | transport of the protected leg (the second REGISTER and everything after it): `tcp`, `udp`, or `auto` = TCP, falling back to a fresh registration over UDP when the P-CSCF leaves two TCP connects unanswered — but only on a phone that has never registered over TCP: once the state file (`/var/lib/imsd/imsreg.state`) records a TCP registration, a silent connect is treated as an outage, not a policy (delete the file or set `udp` to override, e.g. after a SIM change). The challenge (first REGISTER) is always UDP. Over UDP a REGISTER or INVITE larger than ~1.2 KB leaves as IPv6 fragments at the ims PDN's 1280-byte MTU (the journal says so once per flow); there are no SIP retransmission timers over UDP yet, so a lost datagram costs a timeout. The SAs, the listener and the firewall rule cover both transports |
|
||
| `EMERGENCY_NUMBERS` | *(empty)* | comma-separated additions to the builtin 112/911 emergency numbers (e.g. a private test core's short code). SIM `EF_ECC` is not read yet |
|
||
| `RTP_PORT` | `50004` | local RTP port advertised in SDP |
|
||
| `PRECOND` | `0` | `1` offers SDP QoS preconditions |
|
||
| `CODECS` | *(empty — defaults)* | comma-separated codec preference list over `AMR-WB`, `AMR` (or `AMR-NB`), `PCMA`, `PCMU`: restricts and orders both the codecs offered on an outgoing call and those accepted from an inbound offer (default: offer AMR-WB + AMR, accept all four in that order). A bench knob — a network whose gateway transcodes every caller up to AMR-WB otherwise never lets the narrowband path run |
|
||
| `DUMP_SIP` | `0` | `1` writes raw REGISTER-200/SUBSCRIBE-200 dumps, the last refused REGISTER or SUBSCRIBE final (`imsd-register-fail.raw`, `imsd-subscribe-fail.raw`), the last inbound INVITE (`imsd-invite-in.raw`) and the last outgoing INVITE (`imsd-invite-out.raw`), mode 0600, for debugging — they contain your IMSI/MSISDN and addresses. A refused REGISTER or SUBSCRIBE is logged with its status line and any Retry-After / Warning / Reason / Server headers |
|
||
| `DUMP_DIR`, `OUT_DIR` | state dir | where dumps / per-call media stats land |
|
||
| `IMSD_MEDIA` | *(auto)* | path to `imsd-media` (default: next to `imsd`, else `/usr/libexec/imsd-media`) |
|
||
|
||
The protected client/server ports are fixed at 45061/45062
|
||
(`imsd::util::kPortUc`/`kPortUs`) — changing them in source also requires
|
||
updating the firewall rules `ims-pdn-up.sh` installs.
|
||
|
||
**When the registration stops working** (the refresh is refused, or the
|
||
protected flow dies and nothing answers the reconnect) imsd does in place
|
||
what a restart does: it reconnects through the existing SA and refreshes;
|
||
after two refused refreshes or two unanswered reconnect cycles (such a
|
||
cycle is not counted while the modem reports no packet service) it
|
||
registers fresh (new Call-ID, new challenge, new SA pair). Reconnects back
|
||
off 5 s → 5 min; a refused or throttled fresh attempt waits on the throttle
|
||
schedule (21 min, growing to 60), a silent one 30 s → 10 min, and a
|
||
network `Retry-After` is honoured, up to an hour (the schedule's longest wait): a longer
|
||
one is cut to it and the refusal heard again then. While a fresh registration is deferred, the existing SA is
|
||
still retried on the reconnect backoff, unless the old registration is known gone: a `403` once a
|
||
fresh registration is due, an attempt that got past the SA setup, or a binding
|
||
the network terminated (reg-event). A `Dial`
|
||
that reaches imsd while it is unregistered brings the next recovery step
|
||
forward (the reconnect, or the fresh attempt once it is due), never a wait
|
||
the network imposed (a `Retry-After`, or the schedule after a
|
||
refused or throttled fresh attempt); imsd-ofonod refuses a `Dial` then, and
|
||
imsd-dialerd lists no modem. A bring-up the network deferred waits the same
|
||
schedule out with nothing to reconnect over (the resume just found the
|
||
stored SAs unusable), then tries again. The network's holds outlive a
|
||
restart of imsd (an upgrade restarts it): they are kept in
|
||
`/run/imsd.holds` for the PDN they were set on, with the schedule's place
|
||
(a restart does not start it over at 21 min), and waited out at the next
|
||
start, before the resume (a refresh's `Retry-After`) or before the fresh
|
||
registration (a fresh attempt's schedule or `Retry-After`, a terminated
|
||
binding's wait); a reboot or another PDN address starts clean. An upgrade from a daemon
|
||
older than 0.3.10, which kept its bring-up throttle wait in memory only,
|
||
hands that wait over the same way when this start registers on the address
|
||
it was earned on (the fresh-SA throttle's wait, `spi-s=0`; the old daemon's
|
||
other deferrals, after a 401 it could not use, are not handed over): the
|
||
upgrade records that daemon's invocation, and the next
|
||
start reads its journal lines once the daemon has stopped — a wait that
|
||
ended meanwhile is read as it ended; on another address (the normal hop:
|
||
0.3.9 sat on the kernel's temporary address) only the verdict that the old
|
||
registration is gone is kept and the start registers fresh at once. When
|
||
the old address cannot be read the wait is handed over anyway; when the wait
|
||
cannot be timed, or this start has no `LOCAL`, the journal says it was not
|
||
handed over.
|
||
The journal says which (`…; next: fresh registration in N s`, `registering
|
||
fresh (recovery attempt N)`, `fresh registration deferred/refused/failed:
|
||
…`, `bring-up deferred: …`). One case leaves through a real restart
|
||
instead: when the address imsd is registered on has left the ims netdev
|
||
and the PDN's own address is not there to move to (the PDN went away) —
|
||
the journal shows `engine fatal: … — exiting for systemd restart`,
|
||
and after `RestartSec` (120 s) `ims-pdn-up.sh` runs again and imsd
|
||
registers on the PDN's address. A registration resumed on an older
|
||
address (a pre-0.3.10 temporary one) moves to the PDN's own address in
|
||
place: with its next fresh registration, or when the older address leaves
|
||
the netdev first, which takes that registration with it. The reg-event
|
||
subscription — the network's own
|
||
view of the binding, one live dialog per registration, subscribed anew ahead of
|
||
the lifetime the S-CSCF granted — is retried when refused or unanswered
|
||
(60 s doubling to 10 min, a `Retry-After` honoured up to an hour: a registration refresh
|
||
neither brings a scheduled retry forward nor starts its back-off over) and renewed when the S-CSCF ends
|
||
it for a reason that allows renewal (RFC 6665; after `noresource`,
|
||
`rejected` or any other reason the renewal does not cover the next
|
||
registration refresh subscribes anew); an earlier
|
||
subscription's NOTIFY is still read for the binding's state, but its end is
|
||
not ours to renew (KPN closes a registration's previous subscription with
|
||
`noresource` when a new one replaces it); a NOTIFY that terminates the binding triggers a fresh
|
||
registration (at once, or after the network's `retry-after`, up to an hour; after the
|
||
call, when one is up; one exception: a REGISTER wait that still gets its 200
|
||
after such a NOTIFY, a call having kept the flow, leaves that registration
|
||
standing); after
|
||
`rejected` and `unregistered` it waits on the refusal schedule (21 min,
|
||
growing to 60), a wait no `Dial` cuts short — the binding is gone, so
|
||
nothing is retried meanwhile. One termination counts once, however many
|
||
NOTIFYs report it (a repeated `probation` report may extend its hold from
|
||
its own `retry-after`).
|
||
|
||
### imsd-media (per-call, set through imsd's environment)
|
||
|
||
| Variable | Default | Meaning |
|
||
|---|---|---|
|
||
| `MIC`, `PLAY` | `1`, `1` | uplink mic capture / downlink playout via PipeWire |
|
||
| `AUDIO_USER` | *(auto)* | account whose PipeWire session carries call audio. imsd sets it for each call from logind: the user session active on seat0 (`loginctl show-seat seat0`, a greeter does not count) when it has a `/run/user/<uid>/pipewire-0` socket. Set in imsd's own environment it pins an account instead. imsd as packaged (root, on the system bus) logs the resolution at start and when a call's media starts (`audio session: …`), imsd-media once per call. imsd-media started without the variable at all (by an imsd older than 0.3.10 while an upgrade replaces it, or by hand) tries the account `user`, its old default. |
|
||
| `GAIN`, `PLAY_GAIN` | `10`, `1.0` | uplink / downlink gain |
|
||
| `AMR_MODE` | `2` | AMR-WB encoder mode (0–8) |
|
||
| `DTX` | `0` | encoder discontinuous transmission |
|
||
| `MEDIA_TIMEOUT` | `6.0` | seconds of downlink silence before exit 3 (far-end-hangup signal) |
|
||
| `RTP_DUMP` | `0` | `1` captures raw downlink RTP next to the stats file |
|
||
|
||
## D-Bus ABI
|
||
|
||
`net.catcrafts.IMS1` at `/net/catcrafts/IMS1`. The ABI is frozen — dialer
|
||
integrations depend on it:
|
||
|
||
| Member | Signature |
|
||
|---|---|
|
||
| `Dial(number)` | `s → s` (callUni) |
|
||
| `HangUp(callUni)` | `s` |
|
||
| `Accept(callUni)` | `s` |
|
||
| `SendDtmf(callUni, tones)` | `ss` |
|
||
| `GetCalls()` | `→ aa{sv}` |
|
||
| `GetStatus()` | `→ a{sv}` |
|
||
| `CallAdded` | `s a{sv}` |
|
||
| `CallStateChanged` | `s s s` (callUni, state, reason) |
|
||
| `CallDeleted` | `s` |
|
||
| `RegistrationChanged` | `b` |
|
||
|
||
Both `imsd-dialerd` and `imsd-ofonod` translate this ABI and add no members
|
||
to it; a new desktop needs a new translation daemon, not changes here — one
|
||
that runs as root on the system bus also gates its own callers through
|
||
imsd-bus (see Architecture), or it bypasses `net.catcrafts.IMS1.Voice`.
|
||
|
||
## License
|
||
|
||
GPL-3.0-only — see [LICENSE](LICENSE).
|
||
|
||
## Copyright
|
||
|
||
Copyright (C) 2026 Catcrafts®
|
||
catcrafts.net
|