From 6732106210fe87ecb497b86dfa7a451ead65cdb4 Mon Sep 17 00:00:00 2001
From: rnhmjoj <rnhmjoj@inventati.org>
Date: Sat, 27 May 2023 15:09:22 +0200
Subject: [PATCH 1/2] network-interfaces-scripted: fix interface cleanup

There is apparently a bug in the parser of iproute2 where the command
`ip link show <devname>` will not show the device but list all
interfaces (equivalent to `ip link show`) if devname is equal to one of
the flags of `ip-address(8)`. For example, `home`, or `optimistic`.

This bug causes a false positive in the clean up command of the
<devname>-netdev.service, the service fails and the interface is never
configured.

To avoid the bug we can simply use `ip link show dev <devname>`.
---
 nixos/modules/tasks/network-interfaces-scripted.nix | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/nixos/modules/tasks/network-interfaces-scripted.nix b/nixos/modules/tasks/network-interfaces-scripted.nix
index 843082ab858e..24f0c37acf90 100644
--- a/nixos/modules/tasks/network-interfaces-scripted.nix
+++ b/nixos/modules/tasks/network-interfaces-scripted.nix
@@ -293,7 +293,7 @@ let
             script = ''
               # Remove Dead Interfaces
               echo "Removing old bridge ${n}..."
-              ip link show "${n}" >/dev/null 2>&1 && ip link del "${n}"
+              ip link show dev "${n}" >/dev/null 2>&1 && ip link del "${n}"
 
               echo "Adding bridge ${n}..."
               ip link add name "${n}" type bridge
@@ -459,7 +459,7 @@ let
             path = [ pkgs.iproute2 ];
             script = ''
               # Remove Dead Interfaces
-              ip link show "${n}" >/dev/null 2>&1 && ip link delete "${n}"
+              ip link show dev "${n}" >/dev/null 2>&1 && ip link delete "${n}"
               ip link add link "${v.interface}" name "${n}" type macvlan \
                 ${optionalString (v.mode != null) "mode ${v.mode}"}
               ip link set "${n}" up
@@ -517,7 +517,7 @@ let
             path = [ pkgs.iproute2 ];
             script = ''
               # Remove Dead Interfaces
-              ip link show "${n}" >/dev/null 2>&1 && ip link delete "${n}"
+              ip link show dev "${n}" >/dev/null 2>&1 && ip link delete "${n}"
               ip link add name "${n}" type sit \
                 ${optionalString (v.remote != null) "remote \"${v.remote}\""} \
                 ${optionalString (v.local != null) "local \"${v.local}\""} \
@@ -551,7 +551,7 @@ let
             path = [ pkgs.iproute2 ];
             script = ''
               # Remove Dead Interfaces
-              ip link show "${n}" >/dev/null 2>&1 && ip link delete "${n}"
+              ip link show dev "${n}" >/dev/null 2>&1 && ip link delete "${n}"
               ip link add name "${n}" type ${v.type} \
                 ${optionalString (v.remote != null) "remote \"${v.remote}\""} \
                 ${optionalString (v.local != null) "local \"${v.local}\""} \
@@ -579,7 +579,7 @@ let
             path = [ pkgs.iproute2 ];
             script = ''
               # Remove Dead Interfaces
-              ip link show "${n}" >/dev/null 2>&1 && ip link delete "${n}"
+              ip link show dev "${n}" >/dev/null 2>&1 && ip link delete "${n}"
               ip link add link "${v.interface}" name "${n}" type vlan id "${toString v.id}"
 
               # We try to bring up the logical VLAN interface. If the master

From ea0b4a694aeacc4d2f28a001af14c0e9d85fd7ee Mon Sep 17 00:00:00 2001
From: rnhmjoj <rnhmjoj@inventati.org>
Date: Sat, 27 May 2023 19:10:44 +0200
Subject: [PATCH 2/2] nixos/test/networking: test unusual interface names

---
 nixos/tests/networking.nix | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/nixos/tests/networking.nix b/nixos/tests/networking.nix
index 99f0b6db32af..05fed0f4b473 100644
--- a/nixos/tests/networking.nix
+++ b/nixos/tests/networking.nix
@@ -998,6 +998,31 @@ let
         machine.fail("ip address show wlan0 | grep -q ${testMac}")
       '';
     };
+    naughtyInterfaceNames = let
+      ifnames = [
+        # flags of ip-address
+        "home" "temporary" "optimistic"
+        "bridge_slave" "flush"
+        # flags of ip-route
+        "up" "type" "nomaster" "address"
+        # other
+        "very_loong_name" "lowerUpper" "-"
+      ];
+    in {
+      name = "naughtyInterfaceNames";
+      nodes.machine = { pkgs, ... }: {
+        networking.useNetworkd = networkd;
+        networking.bridges = listToAttrs
+          (flip map ifnames
+             (name: { inherit name; value.interfaces = []; }));
+      };
+      testScript = ''
+        machine.start()
+        machine.wait_for_unit("network.target")
+        for ifname in ${builtins.toJSON ifnames}:
+            machine.wait_until_succeeds(f"ip link show dev '{ifname}' | grep -q '{ifname}'")
+      '';
+    };
     caseSensitiveRenaming = {
       name = "CaseSensitiveRenaming";
       nodes.machine = { pkgs, ... }: {