Merge branch 'netdevsim-support-setting-a-permanent-address'

Toke Høiland-Jørgensen says:

====================
netdevsim: support setting a permanent address

Network management daemons that match on the device permanent address
currently have no virtual interface types to test against.
NetworkManager, in particular, has carried an out of tree patch to set
the permanent address on netdevsim devices to use in its CI for this
purpose.

This series adds support to netdevsim to set a permanent address on port
creation, and adds a test script to test setting and getting of the
different L2 address types.

v3: https://lore.kernel.org/20250706-netdevsim-perm_addr-v3-0-88123e2b2027@redhat.com
v2: https://lore.kernel.org/20250702-netdevsim-perm_addr-v2-0-66359a6288f0@redhat.com
v1: https://lore.kernel.org/20250203-netdevsim-perm_addr-v1-1-10084bc93044@redhat.com
====================

Link: https://patch.msgid.link/20250710-netdevsim-perm_addr-v4-0-c9db2fecf3bf@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 83 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 543776596529..66a3ef221ad7 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -63,6 +63,7 @@ TEST_PROGS += ip_local_port_range.sh
 TEST_PROGS += rps_default_mask.sh
 TEST_PROGS += big_tcp.sh
 TEST_PROGS += netns-sysctl.sh
+TEST_PROGS += netdev-l2addr.sh
 TEST_PROGS_EXTENDED := toeplitz_client.sh toeplitz.sh xfrm_policy_add_speed.sh
 TEST_GEN_FILES =  socket nettest
 TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy reuseport_addr_any
diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh
index 35c03e9feebc..c7add0dc4c60 100644
--- a/tools/testing/selftests/net/lib.sh
+++ b/tools/testing/selftests/net/lib.sh
@@ -240,6 +240,29 @@ create_netdevsim() {
     echo nsim$id
 }
 
+create_netdevsim_port() {
+    local nsim_id="$1"
+    local ns="$2"
+    local port_id="$3"
+    local perm_addr="$4"
+    local orig_dev
+    local new_dev
+    local nsim_path
+
+    nsim_path="/sys/bus/netdevsim/devices/netdevsim$nsim_id"
+
+    echo "$port_id $perm_addr" | ip netns exec "$ns" tee "$nsim_path"/new_port > /dev/null || return 1
+
+    orig_dev=$(ip netns exec "$ns" find "$nsim_path"/net/ -maxdepth 1 -name 'e*' | tail -n 1)
+    orig_dev=$(basename "$orig_dev")
+    new_dev="nsim${nsim_id}p$port_id"
+
+    ip -netns "$ns" link set dev "$orig_dev" name "$new_dev"
+    ip -netns "$ns" link set dev "$new_dev" up
+
+    echo "$new_dev"
+}
+
 # Remove netdevsim with given id.
 cleanup_netdevsim() {
     local id="$1"
diff --git a/tools/testing/selftests/net/netdev-l2addr.sh b/tools/testing/selftests/net/netdev-l2addr.sh
new file mode 100755
index 000000000000..18509da293e5
--- /dev/null
+++ b/tools/testing/selftests/net/netdev-l2addr.sh
@@ -0,0 +1,59 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+source lib.sh
+set -o pipefail
+
+NSIM_ADDR=2025
+TEST_ADDR="d0:be:d0:be:d0:00"
+
+RET_CODE=0
+
+cleanup() {
+    cleanup_netdevsim "$NSIM_ADDR"
+    cleanup_ns "$NS"
+}
+
+trap cleanup EXIT
+
+fail() {
+    echo "ERROR: ${1:-unexpected return code} (ret: $_)" >&2
+    RET_CODE=1
+}
+
+get_addr()
+{
+    local type="$1"
+    local dev="$2"
+    local ns="$3"
+
+    ip -j -n "$ns" link show dev "$dev" | jq -er ".[0].$type"
+}
+
+setup_ns NS
+
+nsim=$(create_netdevsim $NSIM_ADDR "$NS")
+
+get_addr address "$nsim" "$NS" >/dev/null || fail "Couldn't get ether addr"
+get_addr broadcast "$nsim" "$NS" >/dev/null || fail "Couldn't get brd addr"
+get_addr permaddr "$nsim" "$NS" >/dev/null && fail "Found perm_addr without setting it"
+
+ip -n "$NS" link set dev "$nsim" address "$TEST_ADDR"
+ip -n "$NS" link set dev "$nsim" brd "$TEST_ADDR"
+
+[[ "$(get_addr address "$nsim" "$NS")" == "$TEST_ADDR" ]] || fail "Couldn't set ether addr"
+[[ "$(get_addr broadcast "$nsim" "$NS")" == "$TEST_ADDR" ]] || fail "Couldn't set brd addr"
+
+if create_netdevsim_port "$NSIM_ADDR" "$NS" 2 "FF:FF:FF:FF:FF:FF" 2>/dev/null; then
+    fail "Created netdevsim with broadcast permaddr"
+fi
+
+nsim_port=$(create_netdevsim_port "$NSIM_ADDR" "$NS" 2 "$TEST_ADDR")
+
+get_addr address "$nsim_port" "$NS" >/dev/null || fail "Couldn't get ether addr"
+get_addr broadcast "$nsim_port" "$NS" >/dev/null || fail "Couldn't get brd addr"
+[[ "$(get_addr permaddr "$nsim_port" "$NS")" == "$TEST_ADDR" ]] || fail "Couldn't get permaddr"
+
+cleanup_netdevsim "$NSIM_ADDR" "$NS"
+
+exit $RET_CODE