From c9fd1e80d3c87e1f844edcd86e9d36ae499ce717 Mon Sep 17 00:00:00 2001

From: Gris Ge <fge@redhat.com>

Date: Sun, 23 Apr 2023 16:01:29 +0800

Subject: [PATCH] cli: Do nothing for `persist-nic-names` when got

 `net.ifnames=0`

When `net.ifnames=0` is defined in kernel argument, systemd will disable

the predicable network interface name which make no sense for nmstate to

pin the interface names. Hence we do nothing in `persist-nic-names` in

that case.

Manually tested in CentOS stream 9 VM.

Signed-off-by: Gris Ge <fge@redhat.com>

---

 rust/src/cli/persist_nic.rs | 19 +++++++++++++++++++

 1 file changed, 19 insertions(+)

diff --git a/rust/src/cli/persist_nic.rs b/rust/src/cli/persist_nic.rs

index 6b126d58..61b07dbb 100644

--- a/rust/src/cli/persist_nic.rs

+++ b/rust/src/cli/persist_nic.rs

@@ -7,6 +7,8 @@

 //!

 //! The logic currently is:

 //!

+//!  - Do nothing if kernel argument contains `net.ifnames=0` which disabled the

+//!    predicable network interface name, hence not fit our use case here.

 //!  - Iterate over all active NICs

 //!  - Pin every ethernet interface to its MAC address (prefer permanent MAC

 //!    address)

@@ -70,6 +72,14 @@ pub(crate) fn run_persist_immediately(

         PersistAction::CleanUpDryRun => return clean_up(root, true),

     };

+    if is_prediable_ifname_disabled() {

+        log::info!(

+            "Systemd predicable network interface name is disabled \

+            by kernel argument `net.ifnames=0`, will do nothing"

+        );

+        return Ok("".to_string());

+    }

+

     let stamp_path = Path::new(root)

         .join(SYSTEMD_NETWORK_LINK_FOLDER)

         .join(NMSTATE_PERSIST_STAMP);

@@ -317,3 +327,12 @@ fn is_nmstate_generated_systemd_link_file(file_path: &PathBuf) -> bool {

         .map(|_| buff == PERSIST_GENERATED_BY.as_bytes())

         .unwrap_or_default()

 }

+

+const KERNEL_CMDLINE_FILE: &str = "/proc/cmdline";

+

+fn is_prediable_ifname_disabled() -> bool {

+    std::fs::read(KERNEL_CMDLINE_FILE)

+        .map(|v| String::from_utf8(v).unwrap_or_default())

+        .map(|c| c.contains("net.ifnames=0"))

+        .unwrap_or_default()

+}

-- 

2.40.0