selftests: net: add netdev-l2addr.sh for testing L2 address functionality

Add a new test script to the network selftests which tests getting and
setting of layer 2 addresses through netlink, including the newly added
support for setting a permaddr on netdevsim devices.

Reviewed-by: Simon Horman <[e-mail]>
Signed-off-by: Toke Høiland-Jørgensen <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

tools/testing/selftests/net/Makefile

···
 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

tools/testing/selftests/net/lib.sh

···
     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"

tools/testing/selftests/net/netdev-l2addr.sh

···
+#!/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