From 6f4e84126aaa4e26cb6865b054ea5ddebd3906e5 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Thu, 3 Feb 2022 12:14:19 +0900
Subject: [PATCH] network: enable KeepConfiguration= when running on network
 filesystem
Cc: pavel@zhukoff.net

Upstream-Status: Submitted [https://github.com/systemd/systemd/pull/22383]
[YOCTO #14708]

network-generator: rename DHCP_TYPE_DHCP -> DHCP_TYPE_DHCP4

To emphasize this is DHCPv4. No behavior is changed.

stat-util: introduce path_is_network_fs()

network: enable KeepConfiguration= when running on network filesystem

Also, set KeepConfiguration=dhcp-on-stop by default when running in
initrd.

Fixes #21967.
---
 man/systemd.network.xml                   |  6 +++--
 src/basic/stat-util.c                     |  9 +++++++
 src/basic/stat-util.h                     |  1 +
 src/network/generator/network-generator.c |  4 ++--
 src/network/generator/network-generator.h |  2 +-
 src/network/networkd-manager.c            | 29 +++++++++++++++++++++++
 src/network/networkd-manager.h            |  2 ++
 src/network/networkd-network.c            | 12 ++++++----
 src/network/test-networkd-conf.c          |  5 ++++
 9 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index af431e4f2c..f90cff4cd6 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -944,8 +944,10 @@ Table=1234</programlisting></para>
           lease expires. This is contrary to the DHCP specification, but may be the best choice if,
           e.g., the root filesystem relies on this connection. The setting <literal>dhcp</literal>
           implies <literal>dhcp-on-stop</literal>, and <literal>yes</literal> implies
-          <literal>dhcp</literal> and <literal>static</literal>. Defaults to <literal>no</literal>.
-          </para>
+          <literal>dhcp</literal> and <literal>static</literal>. Defaults to
+          <literal>dhcp-on-stop</literal> when <command>systemd-networkd</command> is running in
+          initrd, <literal>yes</literal> when the root filesystem is a network filesystem, and
+          <literal>no</literal> otherwise.</para>
         </listitem>
       </varlistentry>
     </variablelist>
diff --git a/src/basic/stat-util.c b/src/basic/stat-util.c
index efac7b002e..c2269844f8 100644
--- a/src/basic/stat-util.c
+++ b/src/basic/stat-util.c
@@ -249,6 +249,15 @@ int path_is_temporary_fs(const char *path) {
         return is_temporary_fs(&s);
 }
 
+int path_is_network_fs(const char *path) {
+        struct statfs s;
+
+        if (statfs(path, &s) < 0)
+                return -errno;
+
+        return is_network_fs(&s);
+}
+
 int stat_verify_regular(const struct stat *st) {
         assert(st);
 
diff --git a/src/basic/stat-util.h b/src/basic/stat-util.h
index a566114f7c..f7d2f12aa9 100644
--- a/src/basic/stat-util.h
+++ b/src/basic/stat-util.h
@@ -53,6 +53,7 @@ int fd_is_temporary_fs(int fd);
 int fd_is_network_fs(int fd);
 
 int path_is_temporary_fs(const char *path);
+int path_is_network_fs(const char *path);
 
 /* Because statfs.t_type can be int on some architectures, we have to cast
  * the const magic to the type, otherwise the compiler warns about
diff --git a/src/network/generator/network-generator.c b/src/network/generator/network-generator.c
index c081ec673c..063ad08d80 100644
--- a/src/network/generator/network-generator.c
+++ b/src/network/generator/network-generator.c
@@ -47,7 +47,7 @@ static const char * const dracut_dhcp_type_table[_DHCP_TYPE_MAX] = {
         [DHCP_TYPE_OFF]     = "off",
         [DHCP_TYPE_ON]      = "on",
         [DHCP_TYPE_ANY]     = "any",
-        [DHCP_TYPE_DHCP]    = "dhcp",
+        [DHCP_TYPE_DHCP4]   = "dhcp",
         [DHCP_TYPE_DHCP6]   = "dhcp6",
         [DHCP_TYPE_AUTO6]   = "auto6",
         [DHCP_TYPE_EITHER6] = "either6",
@@ -62,7 +62,7 @@ static const char * const networkd_dhcp_type_table[_DHCP_TYPE_MAX] = {
         [DHCP_TYPE_OFF]     = "no",
         [DHCP_TYPE_ON]      = "yes",
         [DHCP_TYPE_ANY]     = "yes",
-        [DHCP_TYPE_DHCP]    = "ipv4",
+        [DHCP_TYPE_DHCP4]   = "ipv4",
         [DHCP_TYPE_DHCP6]   = "ipv6",
         [DHCP_TYPE_AUTO6]   = "no",   /* TODO: enable other setting? */
         [DHCP_TYPE_EITHER6] = "ipv6", /* TODO: enable other setting? */
diff --git a/src/network/generator/network-generator.h b/src/network/generator/network-generator.h
index dd0a58738b..0e0da2a57a 100644
--- a/src/network/generator/network-generator.h
+++ b/src/network/generator/network-generator.h
@@ -13,7 +13,7 @@ typedef enum DHCPType {
         DHCP_TYPE_OFF,
         DHCP_TYPE_ON,
         DHCP_TYPE_ANY,
-        DHCP_TYPE_DHCP,
+        DHCP_TYPE_DHCP4,
         DHCP_TYPE_DHCP6,
         DHCP_TYPE_AUTO6,
         DHCP_TYPE_EITHER6,
diff --git a/src/network/networkd-manager.c b/src/network/networkd-manager.c
index 7e89366ae8..3261f289e9 100644
--- a/src/network/networkd-manager.c
+++ b/src/network/networkd-manager.c
@@ -398,6 +398,30 @@ static int signal_restart_callback(sd_event_source *s, const struct signalfd_sig
         return sd_event_exit(sd_event_source_get_event(s), 0);
 }
 
+static int manager_set_keep_configuration(Manager *m) {
+        int r;
+
+        assert(m);
+
+        if (in_initrd()) {
+                log_debug("Running in initrd, keep DHCPv4 addresses on stopping networkd by default.");
+                m->keep_configuration = KEEP_CONFIGURATION_DHCP_ON_STOP;
+                return 0;
+        }
+
+        r = path_is_network_fs("/");
+        if (r < 0)
+                return log_error_errno(r, "Failed to detect if root is network filesystem: %m");
+        if (r == 0) {
+                m->keep_configuration = _KEEP_CONFIGURATION_INVALID;
+                return 0;
+        }
+
+        log_debug("Running on network filesystem, enabling KeepConfiguration= by default.");
+        m->keep_configuration = KEEP_CONFIGURATION_YES;
+        return 0;
+}
+
 int manager_setup(Manager *m) {
         int r;
 
@@ -453,6 +477,10 @@ int manager_setup(Manager *m) {
         if (r < 0)
                 return r;
 
+        r = manager_set_keep_configuration(m);
+        if (r < 0)
+                return r;
+
         m->state_file = strdup("/run/systemd/netif/state");
         if (!m->state_file)
                 return -ENOMEM;
@@ -468,6 +496,7 @@ int manager_new(Manager **ret, bool test_mode) {
                 return -ENOMEM;
 
         *m = (Manager) {
+                .keep_configuration = _KEEP_CONFIGURATION_INVALID,
                 .test_mode = test_mode,
                 .speed_meter_interval_usec = SPEED_METER_DEFAULT_TIME_INTERVAL,
                 .online_state = _LINK_ONLINE_STATE_INVALID,
diff --git a/src/network/networkd-manager.h b/src/network/networkd-manager.h
index 36313589a3..86de529124 100644
--- a/src/network/networkd-manager.h
+++ b/src/network/networkd-manager.h
@@ -28,6 +28,8 @@ struct Manager {
         Hashmap *polkit_registry;
         int ethtool_fd;
 
+        KeepConfiguration keep_configuration;
+
         bool test_mode;
         bool enumerating;
         bool dirty;
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 3142be471f..edcd68d616 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -124,6 +124,7 @@ int network_verify(Network *network) {
         int r;
 
         assert(network);
+        assert(network->manager);
         assert(network->filename);
 
         if (net_match_is_empty(&network->match) && !network->conditions)
@@ -248,10 +249,11 @@ int network_verify(Network *network) {
         }
 
         if (network->dhcp_critical >= 0) {
-                if (network->keep_configuration >= 0)
-                        log_warning("%s: Both KeepConfiguration= and deprecated CriticalConnection= are set. "
-                                    "Ignoring CriticalConnection=.", network->filename);
-                else if (network->dhcp_critical)
+                if (network->keep_configuration >= 0) {
+                        if (network->manager->keep_configuration < 0)
+                                log_warning("%s: Both KeepConfiguration= and deprecated CriticalConnection= are set. "
+                                            "Ignoring CriticalConnection=.", network->filename);
+                } else if (network->dhcp_critical)
                         /* CriticalConnection=yes also preserve foreign static configurations. */
                         network->keep_configuration = KEEP_CONFIGURATION_YES;
                 else
@@ -386,7 +388,7 @@ int network_load_one(Manager *manager, OrderedHashmap **networks, const char *fi
                 .allmulticast = -1,
                 .promiscuous = -1,
 
-                .keep_configuration = _KEEP_CONFIGURATION_INVALID,
+                .keep_configuration = manager->keep_configuration,
 
                 .dhcp_duid.type = _DUID_TYPE_INVALID,
                 .dhcp_critical = -1,
diff --git a/src/network/test-networkd-conf.c b/src/network/test-networkd-conf.c
index 4b00a98086..5f1328e39c 100644
--- a/src/network/test-networkd-conf.c
+++ b/src/network/test-networkd-conf.c
@@ -6,6 +6,7 @@
 #include "net-condition.h"
 #include "networkd-address.h"
 #include "networkd-conf.h"
+#include "networkd-manager.h"
 #include "networkd-network.h"
 #include "strv.h"
 
@@ -166,11 +167,15 @@ static void test_config_parse_ether_addr(void) {
 }
 
 static void test_config_parse_address_one(const char *rvalue, int family, unsigned n_addresses, const union in_addr_union *u, unsigned char prefixlen) {
+        _cleanup_(manager_freep) Manager *manager = NULL;
         _cleanup_(network_unrefp) Network *network = NULL;
 
+        assert_se(manager_new(&manager, /* test_mode = */ true) >= 0);
         assert_se(network = new0(Network, 1));
         network->n_ref = 1;
+        network->manager = manager;
         assert_se(network->filename = strdup("hogehoge.network"));
+
         assert_se(config_parse_match_ifnames("network", "filename", 1, "section", 1, "Name", 0, "*", &network->match.ifname, network) == 0);
         assert_se(config_parse_address("network", "filename", 1, "section", 1, "Address", 0, rvalue, network, network) == 0);
         assert_se(ordered_hashmap_size(network->addresses_by_section) == 1);
-- 
2.34.1