src/net: first automated test case, run with unshare

Run with unshare, as so:

    make clean; make; cd test/
    unshare -mrun ./three-independent.sh

This sets up a test directory in /tmp/net, creates three independtent
interface configs for dummy interfaces.  Activates the config with a
call to `net -vd apply`, and then verifies the result using a mix of
ip link/addr and jq magic.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/net/test/three-independent.sh

@@ -0,0 +1,83 @@
+#!/bin/sh
+# - Verify correct bring up of three independent interfaces
+# - Verify removal of one
+# - Verify net down
+# - Verify net up <one>
+
+NET_DIR=/tmp/net
+export NET_DIR
+
+gen=-1
+
+init()
+{
+    ip link set lo up
+}
+
+netdo()
+{
+    ../net -vd apply
+}
+
+create_ng()
+{
+    _=$((gen += 1))
+    mkdir -p "$NET_DIR/$gen"
+    echo $gen > "$NET_DIR/next"
+}
+
+create_iface()
+{
+    ifname=$1
+    address=$2
+
+    mkdir -p "$NET_DIR/$gen/$ifname/deps"
+    cat <<-EOF >"$NET_DIR/$gen/$ifname/init.ip"
+	link add $ifname type dummy
+	addr add $address dev $ifname
+	link set $ifname up
+EOF
+    echo "up" > "$NET_DIR/$gen/$ifname/admin-state"
+}
+
+check_iface()
+{
+    ifname=$1
+    address=$2
+    state=$(tr '[:lower:]' '[:upper:]' < "$NET_DIR/$gen/$ifname/admin-state")
+
+    addr=$(ip -br -j addr show "$ifname" | jq -r '.[] | .addr_info[0].local')
+    plen=$(ip -br -j addr show "$ifname" | jq -r '.[] | .addr_info[0].prefixlen')
+    addr="$addr/$plen"
+    updn=$(ip -br -j link show "$ifname" | jq -r '.[] | .flags[] | select(index("UP"))' | head -1)
+
+    echo "$state => $ifname: $updn $addr"
+
+    if [ "$state" != "$updn" ]; then
+	echo "Failed to bring $ifname $state ($updn)"
+	exit 1
+    fi
+    if [ "$address" != "$addr" ]; then
+	echo "Failed to set $ifname $address ($addr)"
+	exit 1
+    fi
+}
+
+init
+
+create_ng
+create_iface eth0 10.0.0.1/24
+create_iface eth1 10.0.1.1/24
+create_iface eth2 10.0.2.1/24
+tree "$NET_DIR/"
+netdo
+
+check_iface eth0 10.0.0.1/24
+check_iface eth1 10.0.1.1/24
+check_iface eth2 10.0.2.1/24
+
+ip link
+ip addr
+
+
+tree "$NET_DIR/"