From 3255bda698d2a02ab2f2825a1e652ac6f0871a89 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 17 Jan 2024 01:35:34 +0900
Subject: [PATCH] network: make 'carrier' as the default required operational
 state for CAN device

As CAN devices do not support IP address, hence the state never goes to
higher than 'carrier'.

Prompted by https://github.com/linux-can/can-utils/issues/68#issuecomment-1327987724.
---
 man/systemd.network.xml        | 11 +++++++++--
 src/network/networkd-link.c    |  5 +++++
 src/network/networkd-network.c |  4 ++--
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index 76f9f4d042..35c897af39 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -259,8 +259,9 @@
       <varlistentry>
         <term><varname>RequiredForOnline=</varname></term>
         <listitem>
-          <para>Takes a boolean or a minimum operational state and an optional maximum operational
-          state. Please see
+          <para>Takes a boolean, a minimum operational state (e.g., <literal>carrier</literal>), or a range
+          of operational state separated with a colon (e.g., <literal>degraded:routable</literal>).
+          Please see
           <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
           for possible operational states. When <literal>yes</literal>, the network is deemed required
           when determining whether the system is online (including when running
@@ -270,6 +271,12 @@
           minimum and maximum operational state required for the network interface to be considered
           online.</para>
 
+          <para>When <literal>yes</literal> is specified for a CAN device,
+          <command>systemd-networkd-wait-online</command> deems that the interface is online when its
+          operational state becomes <literal>carrier</literal>. For an interface with other type, e.g.
+          <literal>ether</literal>, the interface is deened online when its online state is
+          <literal>degraded</literal> or <literal>routable</literal>.</para>
+
           <para>Defaults to <literal>yes</literal> when <varname>ActivationPolicy=</varname> is not
           set, or set to <literal>up</literal>, <literal>always-up</literal>, or
           <literal>bound</literal>. Defaults to <literal>no</literal> when
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index d553a716fa..57ea9ecb75 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -77,6 +77,11 @@ void link_required_operstate_for_online(Link *link, LinkOperationalStateRange *r
 
         if (link->network && operational_state_range_is_valid(&link->network->required_operstate_for_online))
                 *ret = link->network->required_operstate_for_online;
+        else if (link->iftype == ARPHRD_CAN)
+                *ret = (const LinkOperationalStateRange) {
+                        .min = LINK_OPERSTATE_CARRIER,
+                        .max = LINK_OPERSTATE_CARRIER,
+                };
         else
                 *ret = LINK_OPERSTATE_RANGE_DEFAULT;
 }
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 845a8130bd..08c7da5699 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -372,7 +372,7 @@ int network_load_one(Manager *manager, OrderedHashmap **networks, const char *fi
                 .n_ref = 1,
 
                 .required_for_online = -1,
-                .required_operstate_for_online = LINK_OPERSTATE_RANGE_DEFAULT,
+                .required_operstate_for_online = LINK_OPERSTATE_RANGE_INVALID,
                 .activation_policy = _ACTIVATION_POLICY_INVALID,
                 .group = -1,
                 .arp = -1,
@@ -1221,7 +1221,7 @@ int config_parse_required_for_online(
 
         if (isempty(rvalue)) {
                 network->required_for_online = -1;
-                network->required_operstate_for_online = LINK_OPERSTATE_RANGE_DEFAULT;
+                network->required_operstate_for_online = LINK_OPERSTATE_RANGE_INVALID;
                 return 0;
         }