2026-07-22 22:53:28 +02:00
<!-- 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
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
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.
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## 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.
## Architecture
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
C++26 modules, built with Crafter Build. Five build products:
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- **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. All GLib and I/O live here.
- **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).
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
- **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 only, no core; 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.
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### 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.
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Everything below has been verified by community members to be fully workking:
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2026-08-12 14:25:09 +02:00
| Device | OS | Carrier
|---|---|---|
| The Fairphone (Gen. 6) | postmarketOS, Linux 7.1.2 | KPN NL |
2026-08-12 15:44:52 +02:00
| The Fairphone (Gen. 6) | postmarketOS, Linux 7.1.2 | Telekom Deutschland GER |
2026-08-13 17:33:58 +02:00
| The Fairphone (Gen. 6) | postmarketOS, Linux 7.1.2 | Phonero |
| The Fairphone (Gen. 6) | postmarketOS, Linux 7.1.2 | Telia Norge |
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## 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)
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
crafter-build -- --product=dialerd # bin/imsd-dialerd-.../imsd-dialerd (Plasma backend)
crafter-build -- --product=ofonod # bin/imsd-ofonod-.../imsd-ofonod (GNOME Calls backend)
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crafter-build test # unit tests (Util, Aka, Ipsec, Messages, Engine, Sip, Sdp)
```
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### 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
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
make # build/make/{imsd,imsd-media,imsd-dialerd,imsd-ofonod}
2026-08-07 21:05:33 +02:00
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.
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### 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 \
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--march=armv8.6-a+fp16fml+aes+sha3+sm4 --mtune=cortex-a720
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# 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 (policy in
`packaging/net.catcrafts.IMS1.conf` — it grants the postmarketOS default
imsd, media: aim call audio at logind's seat0 session, not an account named `user`
imsd-media defaulted AUDIO_USER to `user`, postmarketOS's default
account name, and with no such account a call had no audio on the phone
and noise at the far end, the message only in imsd-media's stderr, at
each call. A field user found it by trial (alyx report 14, 2026-09-20;
ims ledger F14).
Have imsd, as packaged (root, on the system bus), resolve the session
from logind when a call's media starts — the user session active on
seat0 (a greeter is not one) when it has a PipeWire socket — and hand it
to imsd-media as AUDIO_USER; set in imsd's own environment to an
account's name, AUDIO_USER pins that account instead. imsd as packaged
(root, on the system bus) logs the resolution at start, before the first
call, and when a call's media starts.
No session is an empty AUDIO_USER. imsd-media started without the
variable at all keeps `user`: that is an imsd older than 0.3.10, still
running while an upgrade replaces the helper under it, whose calls would
otherwise be silent until the restart, or a hand run.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-25 17:15:02 +02:00
account `user` access; adjust it if your session account is named
differently), started by `packaging/imsd.service`
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after `packaging/ims-pdn-up.sh` has brought up the ims PDN through
packaging: restart imsd and imsd-ofonod on upgrade
An upgrade left the old imsd and imsd-ofonod running until they were
next restarted, while a changed bus policy is live the moment apk writes
it: dbus-broker-launch reloads on its own. A policy that relies on a
check inside the daemons would face the old daemons in between.
Mark imsd.service and imsd-ofonod.service needs-restart in post-upgrade
scripts; the systemd trigger restarts them once the transaction is done
(enqueue-marked). A call in progress ends. The same scripts run as
post-install: `apk del` removes a package's files and leaves its daemon
running, so a later `apk add` of the package is this upgrade for that
daemon — and apk runs the post-install script, not post-upgrade, for a
package it adds. GNOME Calls 50.0 dials nothing after imsd-ofonod
restarts under it until it restarts too, so imsd-ofonod's ExecStartPost
restarts the Calls daemon of each user running one — not at the unit's
first start since boot, when a Calls that runs already is left alone.
A daemon older than 0.3.10 kept its bring-up throttle wait in memory
only, so a restart lost it. imsd's post-upgrade records that daemon's
invocation, and imsd-handover.sh, an ExecStartPre after ims-pdn-up.sh,
reads the invocation's journal and, while the fresh-SA throttle's wait
it finds there still runs (`spi-s=0`; the old daemon's other deferrals
are not handed over), writes what is left of it to the holds file when
this start's LOCAL is the address the wait was earned on, or when that
address cannot be read; when LOCAL is another address, only the verdict
that the old registration is gone.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-04 00:09:37 +02:00
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
ims-pdn-up: never let the ims PDN be the IPv6 default route
The PGW's router advertisement on the ims netdev offers a default
router, and on IPv4-only wifi that is the phone's only IPv6 default
route. Every AAAA-first client (apk, browsers) then sends its SYN into
the IMS walled garden, which drops it: apk sat in SYN-SENT for nine
minutes on the dev phone, and a field user's remedy was to stop imsd
before package work.
Set accept_ra_defrtr=0 on the muxed netdev before link-up (the router
solicitation goes out once the link-local address passes DAD), flush a
default route an earlier RA installed (an imsd restart), and give the
P-CSCF a host route over the netdev instead. imsd talks to the P-CSCF
only and already installs a host route per media peer; the RA's prefix
and MTU still apply. The host route makes the P-CSCF reachable before
the RA has been processed, so the PDN MTU ModemManager reports is set
on the link as well, the way NetworkManager does for its bearers. A
failed host route, or a P-CSCF that is not an IPv6 address (the PDN is
brought up IPv6-only), fails the unit with a clear message.
Dev phone (KPN, 0.3.8-r0): restart path drops the RA default and
registers over the host route, apk update in 6 s where it hung; MO and
MT calls with audio both ways; cold boot never installs the default
route, the link carries the 1280 MTU before the host route exists,
fresh registration in 1 s.
2026-09-24 04:12:39 +02:00
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
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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
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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.
2026-07-22 22:53:28 +02:00
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
## 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
ofonod: keep VoiceCallManager published across imsd restarts; enable on install
GNOME Calls 50.0 builds one origin per appearance of the modem's
VoiceCallManager interface and never disconnects a removed origin's
CallAdded handler, so every withdraw/re-add cycle leaves a stale handler
behind: calls announced twice after one cycle, a SIGBUS on freed memory
after a few (measured on a Fairphone 6). Withdrawing the interface on
every imsd restart or registration drop therefore cost the only incoming
call path on Phosh, where Calls runs as the session's daemon.
List the interface permanently. Registration is reported through the
modem's Online property and enforced in Dial, which now fails with
"imsd is not registered" or "imsd is not running". Only this daemon's own
restart (org.ofono vanishing) still cycles the origin, and the README says
to restart Calls after that.
Installing the opt-in imsd-ofono subpackage now enables imsd-ofonod (a
systemd preset plus the wants symlink, like imsd.service in the main
package), and imsd-dialerd's autostart is limited to KDE so a Phosh
session does not run the Plasma shim.
Verified on the FP6 under Phosh with GNOME Calls' autostarted daemon:
outgoing call, incoming call answered on the lock screen, then an imsd
restart under the running Calls (Online changes only, no origin cycle)
followed by another incoming call added once and answered.
2026-09-20 16:58:42 +02:00
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
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
# 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.
packaging: restart imsd and imsd-ofonod on upgrade
An upgrade left the old imsd and imsd-ofonod running until they were
next restarted, while a changed bus policy is live the moment apk writes
it: dbus-broker-launch reloads on its own. A policy that relies on a
check inside the daemons would face the old daemons in between.
Mark imsd.service and imsd-ofonod.service needs-restart in post-upgrade
scripts; the systemd trigger restarts them once the transaction is done
(enqueue-marked). A call in progress ends. The same scripts run as
post-install: `apk del` removes a package's files and leaves its daemon
running, so a later `apk add` of the package is this upgrade for that
daemon — and apk runs the post-install script, not post-upgrade, for a
package it adds. GNOME Calls 50.0 dials nothing after imsd-ofonod
restarts under it until it restarts too, so imsd-ofonod's ExecStartPost
restarts the Calls daemon of each user running one — not at the unit's
first start since boot, when a Calls that runs already is left alone.
A daemon older than 0.3.10 kept its bring-up throttle wait in memory
only, so a restart lost it. imsd's post-upgrade records that daemon's
invocation, and imsd-handover.sh, an ExecStartPre after ims-pdn-up.sh,
reads the invocation's journal and, while the fresh-SA throttle's wait
it finds there still runs (`spi-s=0`; the old daemon's other deferrals
are not handed over), writes what is left of it to the holds file when
this start's LOCAL is the address the wait was earned on, or when that
address cannot be read; when LOCAL is another address, only the verdict
that the old registration is gone.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-04 00:09:37 +02:00
- **Restarting `imsd-ofonod` restarts GNOME Calls with it.** When the
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
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
ofonod: keep VoiceCallManager published across imsd restarts; enable on install
GNOME Calls 50.0 builds one origin per appearance of the modem's
VoiceCallManager interface and never disconnects a removed origin's
CallAdded handler, so every withdraw/re-add cycle leaves a stale handler
behind: calls announced twice after one cycle, a SIGBUS on freed memory
after a few (measured on a Fairphone 6). Withdrawing the interface on
every imsd restart or registration drop therefore cost the only incoming
call path on Phosh, where Calls runs as the session's daemon.
List the interface permanently. Registration is reported through the
modem's Online property and enforced in Dial, which now fails with
"imsd is not registered" or "imsd is not running". Only this daemon's own
restart (org.ofono vanishing) still cycles the origin, and the README says
to restart Calls after that.
Installing the opt-in imsd-ofono subpackage now enables imsd-ofonod (a
systemd preset plus the wants symlink, like imsd.service in the main
package), and imsd-dialerd's autostart is limited to KDE so a Phosh
session does not run the Plasma shim.
Verified on the FP6 under Phosh with GNOME Calls' autostarted daemon:
outgoing call, incoming call answered on the lock screen, then an imsd
restart under the running Calls (Online changes only, no origin cycle)
followed by another incoming call added once and answered.
2026-09-20 16:58:42 +02:00
`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`
packaging: restart imsd and imsd-ofonod on upgrade
An upgrade left the old imsd and imsd-ofonod running until they were
next restarted, while a changed bus policy is live the moment apk writes
it: dbus-broker-launch reloads on its own. A policy that relies on a
check inside the daemons would face the old daemons in between.
Mark imsd.service and imsd-ofonod.service needs-restart in post-upgrade
scripts; the systemd trigger restarts them once the transaction is done
(enqueue-marked). A call in progress ends. The same scripts run as
post-install: `apk del` removes a package's files and leaves its daemon
running, so a later `apk add` of the package is this upgrade for that
daemon — and apk runs the post-install script, not post-upgrade, for a
package it adds. GNOME Calls 50.0 dials nothing after imsd-ofonod
restarts under it until it restarts too, so imsd-ofonod's ExecStartPost
restarts the Calls daemon of each user running one — not at the unit's
first start since boot, when a Calls that runs already is left alone.
A daemon older than 0.3.10 kept its bring-up throttle wait in memory
only, so a restart lost it. imsd's post-upgrade records that daemon's
invocation, and imsd-handover.sh, an ExecStartPre after ims-pdn-up.sh,
reads the invocation's journal and, while the fresh-SA throttle's wait
it finds there still runs (`spi-s=0`; the old daemon's other deferrals
are not handed over), writes what is left of it to the holds file when
this start's LOCAL is the address the wait was earned on, or when that
address cannot be read; when LOCAL is another address, only the verdict
that the old registration is gone.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-04 00:09:37 +02:00
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.
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
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
```
2026-07-22 22:53:28 +02:00
## Configuration
Everything is environment variables. The packaged unit reads
ims-pdn-up, imsd: register on the PDN's own address, not the kernel's temporary one
imsd took the first global IPv6 on the ims netdev as its address, and
the kernel lists the temporary (privacy) SLAAC address first: `temporary
dynamic`, preferred for a day and valid for two by its lifetimes (read
2026-09-24). Contact, Via and the four SAs were bound to it, so once the
kernel removes it the registration has lost its address. The address
ModemManager assigned — the one the script installs — sat third on the
list. Seen on the dev phone; a field unit's journal shows the split too
— imsd registered on an address other than the one the script installed
(ims ledger F18).
Hand the assigned address to the daemon as LOCAL through /run/imsd.env,
next to DEV. For a manual run without it, prefer a global address that
is neither `temporary` nor `dynamic`, then any non-temporary one.
A restart after the upgrade finds the registration's SAs on the old
address. It resumes there while that address is still on the link, and
moves to the PDN's address in place: with its next fresh registration,
or when the old address leaves the link first. When the address it is
registered on leaves the netdev and the PDN's own address is not there
to move to, a registered imsd exits at its next recovery step, non-zero,
for a systemd restart, which runs the PDN bring-up again.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-28 18:28:58 +02:00
`/run/imsd.env` (written by `ims-pdn-up.sh` : the connected ims netdev and
the PDN address ModemManager assigned to it) and
2026-07-22 22:53:28 +02:00
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` |
ims-pdn-up, imsd: register on the PDN's own address, not the kernel's temporary one
imsd took the first global IPv6 on the ims netdev as its address, and
the kernel lists the temporary (privacy) SLAAC address first: `temporary
dynamic`, preferred for a day and valid for two by its lifetimes (read
2026-09-24). Contact, Via and the four SAs were bound to it, so once the
kernel removes it the registration has lost its address. The address
ModemManager assigned — the one the script installs — sat third on the
list. Seen on the dev phone; a field unit's journal shows the split too
— imsd registered on an address other than the one the script installed
(ims ledger F18).
Hand the assigned address to the daemon as LOCAL through /run/imsd.env,
next to DEV. For a manual run without it, prefer a global address that
is neither `temporary` nor `dynamic`, then any non-temporary one.
A restart after the upgrade finds the registration's SAs on the old
address. It resumes there while that address is still on the link, and
moves to the PDN's address in place: with its next fresh registration,
or when the old address leaves the link first. When the address it is
registered on leaves the netdev and the PDN's own address is not there
to move to, a registered imsd exits at its next recovery step, non-zero,
for a systemd restart, which runs the PDN bring-up again.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-28 18:28:58 +02:00
| `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) |
2026-07-22 22:53:28 +02:00
| `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 |
ims-pdn-up, imsd: register on the PDN's own address, not the kernel's temporary one
imsd took the first global IPv6 on the ims netdev as its address, and
the kernel lists the temporary (privacy) SLAAC address first: `temporary
dynamic`, preferred for a day and valid for two by its lifetimes (read
2026-09-24). Contact, Via and the four SAs were bound to it, so once the
kernel removes it the registration has lost its address. The address
ModemManager assigned — the one the script installs — sat third on the
list. Seen on the dev phone; a field unit's journal shows the split too
— imsd registered on an address other than the one the script installed
(ims ledger F18).
Hand the assigned address to the daemon as LOCAL through /run/imsd.env,
next to DEV. For a manual run without it, prefer a global address that
is neither `temporary` nor `dynamic`, then any non-temporary one.
A restart after the upgrade finds the registration's SAs on the old
address. It resumes there while that address is still on the link, and
moves to the PDN's address in place: with its next fresh registration,
or when the old address leaves the link first. When the address it is
registered on leaves the netdev and the PDN's own address is not there
to move to, a registered imsd exits at its next recovery step, non-zero,
for a systemd restart, which runs the PDN bring-up again.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-28 18:28:58 +02:00
| `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) |
2026-07-22 22:53:28 +02:00
| `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] |
ipsec: build the SAs from the Security-Server mechanism the UE selects
A P-CSCF may answer the challenge with every mechanism it supports and
attach the SPIs and ports to the one it applied. O2 UK's core lists six
ipsec-3gpp entries with q-values, md5 first, and marks the fourth (sha1,
no ealg). imsd took the first ealg= anywhere in the header - the 3DES of
an entry the P-CSCF had not selected - and installed SAs the far end
could not decrypt: every protected packet after the 401 was dropped at
its IPsec layer, over TCP and UDP alike, with nothing to answer.
The 401 handling now parses the Security-Server as a mechanism list
(commas outside quotes, parameters on semicolons, names and values
case-insensitive) and selects the highest-q ipsec-3gpp mechanism that
matches what Security-Client offered (RFC 3329 2.3.1, TS 24.229
5.1.1.5.1): alg equal to ours, ealg (absent = null) equal to the offer.
The SPIs and ports are per registration and come from the entry carrying
them. When no entry matches the offer, the entry carrying the SPIs is
installed as listed and the journal says so; hmac-md5-96 becomes
hmac(md5) with IK as the key. A single-mechanism header selects itself:
on KPN the SAs are the same as before (unit-pinned argv, verified on the
phone). An answer that cannot be used - no ipsec-3gpp entry, a missing
spi/port, an alg, ealg, prot or mod the kernel cannot be handed - defers
the bring-up on the throttle schedule with the reason, before the AKA is
spent, instead of a fatal that would restart imsd every RestartSec with
an initial REGISTER each time; spi-s=0 stays the throttle deferral.
Repeated Security-Server header lines are joined into the one list
Security-Verify echoes.
The journal shows the Security-Server line, the selected mechanism, the
SA parameters, and any ip xfrm command that fails (keys masked) at every
fresh registration - the silence this bug produced had no line to read.
2026-09-19 21:36:57 +02:00
| `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: UDP for the protected leg, TCP first with a fallback
imsd's protected leg (the second REGISTER and everything after it) was
TCP only. A P-CSCF that never answers the TCP connect on its protected
server port (O2 UK: the SYNs leave ESP-protected, nothing comes back)
left the unit looping with no way forward, although the SAs, the
listener sockets and the firewall rule already covered UDP.
The client flow now carries a transport. UDP binds the same protected
client port and connect()s the datagram socket to the P-CSCF's protected
server port, so the kernel delivers that peer's datagrams to it ahead of
the unconnected listener on the same port. One datagram is one message
(RFC 3261 18.3: a Content-Length that fits truncates, one that does not
fit discards the datagram, none means the rest of the datagram); a
receive error is logged and marks the flow dead; a message over the
single-packet ESP budget at the ims PDN's MTU is logged once per flow,
since the kernel fragments it and a P-CSCF may drop the fragments.
Every protected request's Via follows the transport; the challenge
stays UDP.
SIP_TRANSPORT selects the policy: auto (default) registers over TCP and,
after two unanswered connects, registers again over UDP (new challenge,
new SA pair) - but only on a phone whose state file does not record a
successful TCP registration, so an outage on a TCP carrier never becomes
a second initial REGISTER; a phone whose last registration was UDP goes
straight to UDP. tcp and udp force one. A connect refused locally
(EADDRNOTAVAIL: the 4-tuple still in TIME_WAIT from the previous flow)
keeps retrying and is not counted as silence; SO_ERROR results are
logged by name. The registration's transport is persisted so a warm
resume reconnects the same way, and the resume gives up after two
silences.
Two things the change exposed and fixes: an engine-fatal event exited 0
("exiting for systemd restart" with Restart=on-failure never firing),
and a fresh registration refused with the P-CSCF's fresh-SA throttle
(Security-Server spi-s=0) must not be retried by a 120-s restart loop,
since every attempt re-arms the ~20-min window - it is now waited out
in-process, growing on repeats, with D-Bus commands still served. A
resume the network refuses falls through to a fresh registration. A
retransmitted 200 OK to our INVITE is ACKed again and no longer starts
a second media leg.
Verified on KPN: resume over TCP after a binary swap, MT and MO calls
with media both ways, the throttle deferral and its self-recovery, the
UDP client path up to KPN dropping the datagram. The UDP success path
is a field test; SIP retransmission timers over UDP are not in this
change.
2026-09-17 14:58:46 +02:00
| `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 calling, stage 1: urn:service:sos with a digits fallback
Classify 112/911 (plus EMERGENCY_NUMBERS) at Dial. A classified call
INVITEs urn:service:sos over the existing registration and, on any
non-2xx final not caused by the user hanging up (including the
setup-timeout CANCEL paths), retries once as a plain INVITE of the
dialled digits — the pre-0.3.0 behavior, so classification can never
place a call worse than the status quo. The reverse edge: a 380
Alternative Service whose body carries the emergency indication
upgrades an unclassified call to the sos URN; a bare 380 stays an
error, since promoting an arbitrary redirect would put a
non-emergency call through to a PSAP. An emergency dial preempts an
in-progress call, and an answer racing a deadline-initiated CANCEL is
taken instead of BYE'd (user-initiated CANCEL races still BYE).
No emergency registration, no emergency PDN, no CS fallback, no
SIM-less calling, no AML — and no carrier has confirmed the sos path
end-to-end. The README warning states exactly that.
Assisted-by: Claude:claude-fable-5
2026-08-01 22:29:12 +02:00
| `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 |
2026-07-22 22:53:28 +02:00
| `RTP_PORT` | `50004` | local RTP port advertised in SDP |
| `PRECOND` | `0` | `1` offers SDP QoS preconditions |
messages: sign our requests with the public identity, not the IMSI IMPU
Every request we originated — INVITE, CANCEL, both ACKs, in-dialog BYE and
friends — put the IMSI-derived temporary IMPU in From. 3GPP allows that
identity in REGISTER only; the same lesson was learned for the reg-event
SUBSCRIBE (480) and never carried to calls. Most P-CSCFs overwrite From
and hid it; a Telia node did not, and a reporter's IMSI appeared on the
callee's screen (field report 2026-09-01). A strict P-CSCF may reject the
INVITE outright.
CallerId(): the registered sip: public identity (P-Associated-URI), else
the tel: one, and the temporary IMPU only before either is learned. One
helper feeds all five builders, so a dialog's From never drifts. As UAS the
dialog's local URI is the INVITE's To (RFC 3261 12.2.1.1), stored on the
Dialog, so an incoming call's BYE is signed the way the network addressed
us. The identity is persisted in the state file and restored on warm
resume, so a call placed before the refresh 200 re-learns it cannot fall
back. DUMP_SIP now also writes the last outgoing INVITE
(imsd-invite-out.raw): the one request a field log could never show.
The byte-pinned INVITE fixture moves to the tel: identity its test context
knows; new scenarios cover the sip: identity, the tel: fallback, the
pre-learning case and the UAS BYE.
Bench-verified on KPN 2026-09-08: outgoing INVITE From is the registered
sip: identity, call accepted and carried; caller ID at the far end
unchanged.
2026-09-08 20:37:47 +02:00
| `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 |
engine: keep the reg-event subscription alive and act on a terminated binding
The reg-event subscription is the network's own account of our binding
(TS 24.229 5.1.1.3), and the daemon opened a new dialog for it at every
refresh and reconnect and otherwise never looked back: a refused
SUBSCRIBE was forgotten, an unanswered one had no timeout, an ended
subscription got nothing until the next refresh's new dialog, and a
NOTIFY was logged whatever it said. O2 UK, 2026-09-24: a fresh
registration's SUBSCRIBE got 500, a NOTIFY arrived all the same and
showed our contact active, the flow died eight seconds after the 200 and
no connect over the SA succeeded after that; the 500 was logged and
nothing was done about it.
Keep the subscription alive: retry a refused or unanswered SUBSCRIBE on
a backoff, renew one the S-CSCF ends with deactivated, timeout, giveup
or probation (RFC 6665 4.1.3; after any other reason, or none, the next
refresh subscribes anew), and subscribe anew ahead of the lifetime the
S-CSCF granted. A refresh or a reconnect opens no dialog while imsd
holds one for the registration or has a retry scheduled.
Read the reginfo for our own contact and act on its state: a NOTIFY that
terminates our binding schedules a fresh registration — at once for
deactivated or expired, after the network's retry-after (up to an hour)
for probation, on imsd's own refusal schedule (21 min, growing to 60)
for rejected or unregistered (RFC 3680). A hold already running stands,
and a REGISTER wait a call kept open that still gets its 200 after such
a NOTIFY leaves that registration standing. The parser is in Imsd:Sip
and pinned by tests/Sip with the O2 document shapes; the policy is
RegRecovery's (OnBindingTerminated, added here with its tests in
tests/Engine).
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-03 19:36:23 +02:00
| `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 |
2026-07-22 22:53:28 +02:00
| `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.
engine: register fresh when the refresh is refused or nothing answers
After bring-up the daemon recovered a dead protected flow by
reconnecting through the existing SA and refreshing, on a 5 s → 5 min
backoff, forever. That was the whole recovery: a refresh the network
refused, or a P-CSCF that stopped answering, kept it in that loop on the
same Call-ID and SA until someone restarted the service. O2 UK,
2026-09-24: the 30-minute refresh answered 503, 21 refusals over 70 min;
after a manual restart the new registration's flow died 8 s in and no
connect over its SA succeeded for 2 h 39 min; a second restart
registered within two seconds (13:27:55 → 13:27:57 in the journal; ims
ledger F16).
Do in place the rest of what a restart does: when the refresh keeps
being refused, or reconnect cycles keep ending without an answer unless
the modem reports no packet service, register fresh. The fresh
registration is the expensive step, so a failed one waits before the
next: on a schedule (21 min, growing to 60) after a refusal or a
throttle, on a backoff after silence, and a Retry-After from the network
is honoured up to an hour. What the network set — a Retry-After, the
schedule after a refused or throttled attempt — is kept across a restart
in /run/imsd.holds, for the address it was set on. A refused initial
registration at bring-up — a final from 300 up to the unprotected
REGISTER (its 401 is the challenge), any final but 200 to the protected
one, a second 401 (rejected credentials) included — now waits on the
same schedule instead of exiting for a systemd restart every two minutes.
The policy is a pure reducer in Imsd:Engine (RegRecovery), shaped like
the call machine: the daemon supplies the clock and the network, the
reducer holds the deadlines and names the next step, and tests/Engine
pin it. tests/Engine now exits 0 or 1 instead of its failure count: with
more than 255 checks a count of 256 would exit 0, and crafter-build
reads 77 as a skipped suite. The bring-up's deferral is logged in the
policy's form: `bring-up deferred: <why> — attempt N, next fresh
registration in M min` becomes `bring-up deferred: <why>; next: fresh
registration in M min`.
A bring-up writes the verdict that the old registration is gone as well:
a start that goes on to register fresh — its resume failed, or there was
nothing to resume over — records it before the attempt, and when the
attempt then fails without an answer the daemon exits with the file in
place. The next start on the same address and boot does not resume,
where 0.3.9 retried the resume: it registers fresh at once. On KPN, with
the old registration in fact still live — a start during an outage,
staged on the dev phone — that attempt was throttled, and the 21-min
schedule began. A bring-up does not retry its resume through an outage
the way recovery reconnects.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-24 18:56:34 +02:00
**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
engine: keep the reg-event subscription alive and act on a terminated binding
The reg-event subscription is the network's own account of our binding
(TS 24.229 5.1.1.3), and the daemon opened a new dialog for it at every
refresh and reconnect and otherwise never looked back: a refused
SUBSCRIBE was forgotten, an unanswered one had no timeout, an ended
subscription got nothing until the next refresh's new dialog, and a
NOTIFY was logged whatever it said. O2 UK, 2026-09-24: a fresh
registration's SUBSCRIBE got 500, a NOTIFY arrived all the same and
showed our contact active, the flow died eight seconds after the 200 and
no connect over the SA succeeded after that; the 500 was logged and
nothing was done about it.
Keep the subscription alive: retry a refused or unanswered SUBSCRIBE on
a backoff, renew one the S-CSCF ends with deactivated, timeout, giveup
or probation (RFC 6665 4.1.3; after any other reason, or none, the next
refresh subscribes anew), and subscribe anew ahead of the lifetime the
S-CSCF granted. A refresh or a reconnect opens no dialog while imsd
holds one for the registration or has a retry scheduled.
Read the reginfo for our own contact and act on its state: a NOTIFY that
terminates our binding schedules a fresh registration — at once for
deactivated or expired, after the network's retry-after (up to an hour)
for probation, on imsd's own refusal schedule (21 min, growing to 60)
for rejected or unregistered (RFC 3680). A hold already running stands,
and a REGISTER wait a call kept open that still gets its 200 after such
a NOTIFY leaves that registration standing. The parser is in Imsd:Sip
and pinned by tests/Sip with the O2 document shapes; the policy is
RegRecovery's (OnBindingTerminated, added here with its tests in
tests/Engine).
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-03 19:36:23 +02:00
fresh registration is due, an attempt that got past the SA setup, or a binding
the network terminated (reg-event). A `Dial`
engine: register fresh when the refresh is refused or nothing answers
After bring-up the daemon recovered a dead protected flow by
reconnecting through the existing SA and refreshing, on a 5 s → 5 min
backoff, forever. That was the whole recovery: a refresh the network
refused, or a P-CSCF that stopped answering, kept it in that loop on the
same Call-ID and SA until someone restarted the service. O2 UK,
2026-09-24: the 30-minute refresh answered 503, 21 refusals over 70 min;
after a manual restart the new registration's flow died 8 s in and no
connect over its SA succeeded for 2 h 39 min; a second restart
registered within two seconds (13:27:55 → 13:27:57 in the journal; ims
ledger F16).
Do in place the rest of what a restart does: when the refresh keeps
being refused, or reconnect cycles keep ending without an answer unless
the modem reports no packet service, register fresh. The fresh
registration is the expensive step, so a failed one waits before the
next: on a schedule (21 min, growing to 60) after a refusal or a
throttle, on a backoff after silence, and a Retry-After from the network
is honoured up to an hour. What the network set — a Retry-After, the
schedule after a refused or throttled attempt — is kept across a restart
in /run/imsd.holds, for the address it was set on. A refused initial
registration at bring-up — a final from 300 up to the unprotected
REGISTER (its 401 is the challenge), any final but 200 to the protected
one, a second 401 (rejected credentials) included — now waits on the
same schedule instead of exiting for a systemd restart every two minutes.
The policy is a pure reducer in Imsd:Engine (RegRecovery), shaped like
the call machine: the daemon supplies the clock and the network, the
reducer holds the deadlines and names the next step, and tests/Engine
pin it. tests/Engine now exits 0 or 1 instead of its failure count: with
more than 255 checks a count of 256 would exit 0, and crafter-build
reads 77 as a skipped suite. The bring-up's deferral is logged in the
policy's form: `bring-up deferred: <why> — attempt N, next fresh
registration in M min` becomes `bring-up deferred: <why>; next: fresh
registration in M min`.
A bring-up writes the verdict that the old registration is gone as well:
a start that goes on to register fresh — its resume failed, or there was
nothing to resume over — records it before the attempt, and when the
attempt then fails without an answer the daemon exits with the file in
place. The next start on the same address and boot does not resume,
where 0.3.9 retried the resume: it registers fresh at once. On KPN, with
the old registration in fact still live — a start during an outage,
staged on the dev phone — that attempt was throttled, and the 21-min
schedule began. A bring-up does not retry its resume through an outage
the way recovery reconnects.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-24 18:56:34 +02:00
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
packaging: restart imsd and imsd-ofonod on upgrade
An upgrade left the old imsd and imsd-ofonod running until they were
next restarted, while a changed bus policy is live the moment apk writes
it: dbus-broker-launch reloads on its own. A policy that relies on a
check inside the daemons would face the old daemons in between.
Mark imsd.service and imsd-ofonod.service needs-restart in post-upgrade
scripts; the systemd trigger restarts them once the transaction is done
(enqueue-marked). A call in progress ends. The same scripts run as
post-install: `apk del` removes a package's files and leaves its daemon
running, so a later `apk add` of the package is this upgrade for that
daemon — and apk runs the post-install script, not post-upgrade, for a
package it adds. GNOME Calls 50.0 dials nothing after imsd-ofonod
restarts under it until it restarts too, so imsd-ofonod's ExecStartPost
restarts the Calls daemon of each user running one — not at the unit's
first start since boot, when a Calls that runs already is left alone.
A daemon older than 0.3.10 kept its bring-up throttle wait in memory
only, so a restart lost it. imsd's post-upgrade records that daemon's
invocation, and imsd-handover.sh, an ExecStartPre after ims-pdn-up.sh,
reads the invocation's journal and, while the fresh-SA throttle's wait
it finds there still runs (`spi-s=0`; the old daemon's other deferrals
are not handed over), writes what is left of it to the holds file when
this start's LOCAL is the address the wait was earned on, or when that
address cannot be read; when LOCAL is another address, only the verdict
that the old registration is gone.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-04 00:09:37 +02:00
restart of imsd (an upgrade restarts it): they are kept in
ims-pdn-up, imsd: register on the PDN's own address, not the kernel's temporary one
imsd took the first global IPv6 on the ims netdev as its address, and
the kernel lists the temporary (privacy) SLAAC address first: `temporary
dynamic`, preferred for a day and valid for two by its lifetimes (read
2026-09-24). Contact, Via and the four SAs were bound to it, so once the
kernel removes it the registration has lost its address. The address
ModemManager assigned — the one the script installs — sat third on the
list. Seen on the dev phone; a field unit's journal shows the split too
— imsd registered on an address other than the one the script installed
(ims ledger F18).
Hand the assigned address to the daemon as LOCAL through /run/imsd.env,
next to DEV. For a manual run without it, prefer a global address that
is neither `temporary` nor `dynamic`, then any non-temporary one.
A restart after the upgrade finds the registration's SAs on the old
address. It resumes there while that address is still on the link, and
moves to the PDN's address in place: with its next fresh registration,
or when the old address leaves the link first. When the address it is
registered on leaves the netdev and the PDN's own address is not there
to move to, a registered imsd exits at its next recovery step, non-zero,
for a systemd restart, which runs the PDN bring-up again.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-28 18:28:58 +02:00
`/run/imsd.holds` for the PDN they were set on, with the schedule's place
engine: register fresh when the refresh is refused or nothing answers
After bring-up the daemon recovered a dead protected flow by
reconnecting through the existing SA and refreshing, on a 5 s → 5 min
backoff, forever. That was the whole recovery: a refresh the network
refused, or a P-CSCF that stopped answering, kept it in that loop on the
same Call-ID and SA until someone restarted the service. O2 UK,
2026-09-24: the 30-minute refresh answered 503, 21 refusals over 70 min;
after a manual restart the new registration's flow died 8 s in and no
connect over its SA succeeded for 2 h 39 min; a second restart
registered within two seconds (13:27:55 → 13:27:57 in the journal; ims
ledger F16).
Do in place the rest of what a restart does: when the refresh keeps
being refused, or reconnect cycles keep ending without an answer unless
the modem reports no packet service, register fresh. The fresh
registration is the expensive step, so a failed one waits before the
next: on a schedule (21 min, growing to 60) after a refusal or a
throttle, on a backoff after silence, and a Retry-After from the network
is honoured up to an hour. What the network set — a Retry-After, the
schedule after a refused or throttled attempt — is kept across a restart
in /run/imsd.holds, for the address it was set on. A refused initial
registration at bring-up — a final from 300 up to the unprotected
REGISTER (its 401 is the challenge), any final but 200 to the protected
one, a second 401 (rejected credentials) included — now waits on the
same schedule instead of exiting for a systemd restart every two minutes.
The policy is a pure reducer in Imsd:Engine (RegRecovery), shaped like
the call machine: the daemon supplies the clock and the network, the
reducer holds the deadlines and names the next step, and tests/Engine
pin it. tests/Engine now exits 0 or 1 instead of its failure count: with
more than 255 checks a count of 256 would exit 0, and crafter-build
reads 77 as a skipped suite. The bring-up's deferral is logged in the
policy's form: `bring-up deferred: <why> — attempt N, next fresh
registration in M min` becomes `bring-up deferred: <why>; next: fresh
registration in M min`.
A bring-up writes the verdict that the old registration is gone as well:
a start that goes on to register fresh — its resume failed, or there was
nothing to resume over — records it before the attempt, and when the
attempt then fails without an answer the daemon exits with the file in
place. The next start on the same address and boot does not resume,
where 0.3.9 retried the resume: it registers fresh at once. On KPN, with
the old registration in fact still live — a start during an outage,
staged on the dev phone — that attempt was throttled, and the 21-min
schedule began. A bring-up does not retry its resume through an outage
the way recovery reconnects.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-24 18:56:34 +02:00
(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
engine: keep the reg-event subscription alive and act on a terminated binding
The reg-event subscription is the network's own account of our binding
(TS 24.229 5.1.1.3), and the daemon opened a new dialog for it at every
refresh and reconnect and otherwise never looked back: a refused
SUBSCRIBE was forgotten, an unanswered one had no timeout, an ended
subscription got nothing until the next refresh's new dialog, and a
NOTIFY was logged whatever it said. O2 UK, 2026-09-24: a fresh
registration's SUBSCRIBE got 500, a NOTIFY arrived all the same and
showed our contact active, the flow died eight seconds after the 200 and
no connect over the SA succeeded after that; the 500 was logged and
nothing was done about it.
Keep the subscription alive: retry a refused or unanswered SUBSCRIBE on
a backoff, renew one the S-CSCF ends with deactivated, timeout, giveup
or probation (RFC 6665 4.1.3; after any other reason, or none, the next
refresh subscribes anew), and subscribe anew ahead of the lifetime the
S-CSCF granted. A refresh or a reconnect opens no dialog while imsd
holds one for the registration or has a retry scheduled.
Read the reginfo for our own contact and act on its state: a NOTIFY that
terminates our binding schedules a fresh registration — at once for
deactivated or expired, after the network's retry-after (up to an hour)
for probation, on imsd's own refusal schedule (21 min, growing to 60)
for rejected or unregistered (RFC 3680). A hold already running stands,
and a REGISTER wait a call kept open that still gets its 200 after such
a NOTIFY leaves that registration standing. The parser is in Imsd:Sip
and pinned by tests/Sip with the O2 document shapes; the policy is
RegRecovery's (OnBindingTerminated, added here with its tests in
tests/Engine).
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-03 19:36:23 +02:00
registration (a fresh attempt's schedule or `Retry-After` , a terminated
packaging: restart imsd and imsd-ofonod on upgrade
An upgrade left the old imsd and imsd-ofonod running until they were
next restarted, while a changed bus policy is live the moment apk writes
it: dbus-broker-launch reloads on its own. A policy that relies on a
check inside the daemons would face the old daemons in between.
Mark imsd.service and imsd-ofonod.service needs-restart in post-upgrade
scripts; the systemd trigger restarts them once the transaction is done
(enqueue-marked). A call in progress ends. The same scripts run as
post-install: `apk del` removes a package's files and leaves its daemon
running, so a later `apk add` of the package is this upgrade for that
daemon — and apk runs the post-install script, not post-upgrade, for a
package it adds. GNOME Calls 50.0 dials nothing after imsd-ofonod
restarts under it until it restarts too, so imsd-ofonod's ExecStartPost
restarts the Calls daemon of each user running one — not at the unit's
first start since boot, when a Calls that runs already is left alone.
A daemon older than 0.3.10 kept its bring-up throttle wait in memory
only, so a restart lost it. imsd's post-upgrade records that daemon's
invocation, and imsd-handover.sh, an ExecStartPre after ims-pdn-up.sh,
reads the invocation's journal and, while the fresh-SA throttle's wait
it finds there still runs (`spi-s=0`; the old daemon's other deferrals
are not handed over), writes what is left of it to the holds file when
this start's LOCAL is the address the wait was earned on, or when that
address cannot be read; when LOCAL is another address, only the verdict
that the old registration is gone.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-04 00:09:37 +02:00
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.
engine: register fresh when the refresh is refused or nothing answers
After bring-up the daemon recovered a dead protected flow by
reconnecting through the existing SA and refreshing, on a 5 s → 5 min
backoff, forever. That was the whole recovery: a refresh the network
refused, or a P-CSCF that stopped answering, kept it in that loop on the
same Call-ID and SA until someone restarted the service. O2 UK,
2026-09-24: the 30-minute refresh answered 503, 21 refusals over 70 min;
after a manual restart the new registration's flow died 8 s in and no
connect over its SA succeeded for 2 h 39 min; a second restart
registered within two seconds (13:27:55 → 13:27:57 in the journal; ims
ledger F16).
Do in place the rest of what a restart does: when the refresh keeps
being refused, or reconnect cycles keep ending without an answer unless
the modem reports no packet service, register fresh. The fresh
registration is the expensive step, so a failed one waits before the
next: on a schedule (21 min, growing to 60) after a refusal or a
throttle, on a backoff after silence, and a Retry-After from the network
is honoured up to an hour. What the network set — a Retry-After, the
schedule after a refused or throttled attempt — is kept across a restart
in /run/imsd.holds, for the address it was set on. A refused initial
registration at bring-up — a final from 300 up to the unprotected
REGISTER (its 401 is the challenge), any final but 200 to the protected
one, a second 401 (rejected credentials) included — now waits on the
same schedule instead of exiting for a systemd restart every two minutes.
The policy is a pure reducer in Imsd:Engine (RegRecovery), shaped like
the call machine: the daemon supplies the clock and the network, the
reducer holds the deadlines and names the next step, and tests/Engine
pin it. tests/Engine now exits 0 or 1 instead of its failure count: with
more than 255 checks a count of 256 would exit 0, and crafter-build
reads 77 as a skipped suite. The bring-up's deferral is logged in the
policy's form: `bring-up deferred: <why> — attempt N, next fresh
registration in M min` becomes `bring-up deferred: <why>; next: fresh
registration in M min`.
A bring-up writes the verdict that the old registration is gone as well:
a start that goes on to register fresh — its resume failed, or there was
nothing to resume over — records it before the attempt, and when the
attempt then fails without an answer the daemon exits with the file in
place. The next start on the same address and boot does not resume,
where 0.3.9 retried the resume: it registers fresh at once. On KPN, with
the old registration in fact still live — a start during an outage,
staged on the dev phone — that attempt was throttled, and the 21-min
schedule began. A bring-up does not retry its resume through an outage
the way recovery reconnects.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-24 18:56:34 +02:00
The journal says which (`…; next: fresh registration in N s` , `registering
fresh (recovery attempt N)`, ` fresh registration deferred/refused/failed:
ims-pdn-up, imsd: register on the PDN's own address, not the kernel's temporary one
imsd took the first global IPv6 on the ims netdev as its address, and
the kernel lists the temporary (privacy) SLAAC address first: `temporary
dynamic`, preferred for a day and valid for two by its lifetimes (read
2026-09-24). Contact, Via and the four SAs were bound to it, so once the
kernel removes it the registration has lost its address. The address
ModemManager assigned — the one the script installs — sat third on the
list. Seen on the dev phone; a field unit's journal shows the split too
— imsd registered on an address other than the one the script installed
(ims ledger F18).
Hand the assigned address to the daemon as LOCAL through /run/imsd.env,
next to DEV. For a manual run without it, prefer a global address that
is neither `temporary` nor `dynamic`, then any non-temporary one.
A restart after the upgrade finds the registration's SAs on the old
address. It resumes there while that address is still on the link, and
moves to the PDN's address in place: with its next fresh registration,
or when the old address leaves the link first. When the address it is
registered on leaves the netdev and the PDN's own address is not there
to move to, a registered imsd exits at its next recovery step, non-zero,
for a systemd restart, which runs the PDN bring-up again.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-28 18:28:58 +02:00
…`, ` 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
engine: keep the reg-event subscription alive and act on a terminated binding
The reg-event subscription is the network's own account of our binding
(TS 24.229 5.1.1.3), and the daemon opened a new dialog for it at every
refresh and reconnect and otherwise never looked back: a refused
SUBSCRIBE was forgotten, an unanswered one had no timeout, an ended
subscription got nothing until the next refresh's new dialog, and a
NOTIFY was logged whatever it said. O2 UK, 2026-09-24: a fresh
registration's SUBSCRIBE got 500, a NOTIFY arrived all the same and
showed our contact active, the flow died eight seconds after the 200 and
no connect over the SA succeeded after that; the 500 was logged and
nothing was done about it.
Keep the subscription alive: retry a refused or unanswered SUBSCRIBE on
a backoff, renew one the S-CSCF ends with deactivated, timeout, giveup
or probation (RFC 6665 4.1.3; after any other reason, or none, the next
refresh subscribes anew), and subscribe anew ahead of the lifetime the
S-CSCF granted. A refresh or a reconnect opens no dialog while imsd
holds one for the registration or has a retry scheduled.
Read the reginfo for our own contact and act on its state: a NOTIFY that
terminates our binding schedules a fresh registration — at once for
deactivated or expired, after the network's retry-after (up to an hour)
for probation, on imsd's own refusal schedule (21 min, growing to 60)
for rejected or unregistered (RFC 3680). A hold already running stands,
and a REGISTER wait a call kept open that still gets its 200 after such
a NOTIFY leaves that registration standing. The parser is in Imsd:Sip
and pinned by tests/Sip with the O2 document shapes; the policy is
RegRecovery's (OnBindingTerminated, added here with its tests in
tests/Engine).
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-10-03 19:36:23 +02:00
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` ).
engine: register fresh when the refresh is refused or nothing answers
After bring-up the daemon recovered a dead protected flow by
reconnecting through the existing SA and refreshing, on a 5 s → 5 min
backoff, forever. That was the whole recovery: a refresh the network
refused, or a P-CSCF that stopped answering, kept it in that loop on the
same Call-ID and SA until someone restarted the service. O2 UK,
2026-09-24: the 30-minute refresh answered 503, 21 refusals over 70 min;
after a manual restart the new registration's flow died 8 s in and no
connect over its SA succeeded for 2 h 39 min; a second restart
registered within two seconds (13:27:55 → 13:27:57 in the journal; ims
ledger F16).
Do in place the rest of what a restart does: when the refresh keeps
being refused, or reconnect cycles keep ending without an answer unless
the modem reports no packet service, register fresh. The fresh
registration is the expensive step, so a failed one waits before the
next: on a schedule (21 min, growing to 60) after a refusal or a
throttle, on a backoff after silence, and a Retry-After from the network
is honoured up to an hour. What the network set — a Retry-After, the
schedule after a refused or throttled attempt — is kept across a restart
in /run/imsd.holds, for the address it was set on. A refused initial
registration at bring-up — a final from 300 up to the unprotected
REGISTER (its 401 is the challenge), any final but 200 to the protected
one, a second 401 (rejected credentials) included — now waits on the
same schedule instead of exiting for a systemd restart every two minutes.
The policy is a pure reducer in Imsd:Engine (RegRecovery), shaped like
the call machine: the daemon supplies the clock and the network, the
reducer holds the deadlines and names the next step, and tests/Engine
pin it. tests/Engine now exits 0 or 1 instead of its failure count: with
more than 255 checks a count of 256 would exit 0, and crafter-build
reads 77 as a skipped suite. The bring-up's deferral is logged in the
policy's form: `bring-up deferred: <why> — attempt N, next fresh
registration in M min` becomes `bring-up deferred: <why>; next: fresh
registration in M min`.
A bring-up writes the verdict that the old registration is gone as well:
a start that goes on to register fresh — its resume failed, or there was
nothing to resume over — records it before the attempt, and when the
attempt then fails without an answer the daemon exits with the file in
place. The next start on the same address and boot does not resume,
where 0.3.9 retried the resume: it registers fresh at once. On KPN, with
the old registration in fact still live — a start during an outage,
staged on the dev phone — that attempt was throttled, and the 21-min
schedule began. A bring-up does not retry its resume through an outage
the way recovery reconnects.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-24 18:56:34 +02:00
2026-07-22 22:53:28 +02:00
### imsd-media (per-call, set through imsd's environment)
| Variable | Default | Meaning |
|---|---|---|
| `MIC` , `PLAY` | `1` , `1` | uplink mic capture / downlink playout via PipeWire |
imsd, media: aim call audio at logind's seat0 session, not an account named `user`
imsd-media defaulted AUDIO_USER to `user`, postmarketOS's default
account name, and with no such account a call had no audio on the phone
and noise at the far end, the message only in imsd-media's stderr, at
each call. A field user found it by trial (alyx report 14, 2026-09-20;
ims ledger F14).
Have imsd, as packaged (root, on the system bus), resolve the session
from logind when a call's media starts — the user session active on
seat0 (a greeter is not one) when it has a PipeWire socket — and hand it
to imsd-media as AUDIO_USER; set in imsd's own environment to an
account's name, AUDIO_USER pins that account instead. imsd as packaged
(root, on the system bus) logs the resolution at start, before the first
call, and when a call's media starts.
No session is an empty AUDIO_USER. imsd-media started without the
variable at all keeps `user`: that is an imsd older than 0.3.10, still
running while an upgrade replaces the helper under it, whose calls would
otherwise be silent until the restart, or a hand run.
Tested on the dev phone (KPN) in builds of this series; not every path
has run there.
2026-09-25 17:15:02 +02:00
| `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. |
2026-07-22 22:53:28 +02:00
| `GAIN` , `PLAY_GAIN` | `10` , `1.0` | uplink / downlink gain |
| `AMR_MODE` | `2` | AMR-WB encoder mode (0–
| `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` |
ofonod: GNOME Calls backend over org.ofono for Phosh and GNOME Mobile
imsd-ofonod presents imsd on the system bus as an oFono modem — Manager at
/, Modem + VoiceCallManager at /imsd, a VoiceCall object per call — which
is what GNOME Calls' bundled ofono provider drives; Calls, Phosh and GNOME
Shell run unmodified. org.gnome.Calls is not a seam a third party can
provide (Calls exports it, nothing feeds it), and Calls' provider plugins
link private headers, so org.ofono is the only D-Bus contract available.
Pure GDBus translation of net.catcrafts.IMS1, no core, like imsd-dialerd.
Packaged as the opt-in imsd-ofono subpackage: the daemon, its unit
(Conflicts=ofono.service), the system-bus policy and a gschema override
that points Calls at the ofono provider instead of mm (the ModemManager
origin would offer the modem's CS voice path, which carries no audio on
these phones). The policy grants root send_destination=org.ofono: under
dbus-broker a broadcast is checked against the sender's send policy for
every name the receiver owns, so without it imsd's call signals never
reach the daemon.
Verified on a Fairphone 6 with GNOME Calls 50.0: outgoing and incoming
calls with audio both ways, answered and hung up through
org.gnome.Calls.Call. Known Calls-side gap documented in the README: after
the VoiceCallManager interface is withdrawn and re-added, Calls keeps the
old origin's CallAdded handler and eventually crashes.
2026-09-20 16:07:46 +02:00
Both `imsd-dialerd` and `imsd-ofonod` are pure translations of this ABI; a new
desktop needs a new translation daemon, not changes here.
2026-07-22 22:53:28 +02:00
## License
GPL-3.0-only — see [LICENSE ](LICENSE ).
## Copyright
Copyright (C) 2026 Catcrafts®
catcrafts.net
