1 files changed, 93 insertions, 0 deletions
diff --git a/tests/integration/deckard/networking.py b/tests/integration/deckard/networking.py
new file mode 100644
index 0000000..6b76273
--- /dev/null
+++ b/tests/integration/deckard/networking.py
@@ -0,0 +1,93 @@
+import errno
+from ipaddress import IPv4Network, IPv6Network, ip_address
+from socket import AF_INET, AF_INET6
+
+# pylint: disable=no-name-in-module,import-error
+from pyroute2 import IPRoute
+from pyroute2.netlink.rtnl import ndmsg
+from pyroute2.netlink.exceptions import NetlinkError
+# pylint: enable=no-name-in-module,import-error
+
+
+class InterfaceManager:
+    """Wrapper for the `ip` command."""
+
+    def __init__(self,
+                 interface="deckard",
+                 ip4_range=IPv4Network('127.127.0.0/16'),
+                 ip6_range=IPv6Network('fd00:dec::/32')):
+        self.ip4_internal_range = ip4_range
+        self.ip6_internal_range = ip6_range
+        self.ip4_iterator = (host for host in ip4_range)
+        self.ip6_iterator = (host for host in ip6_range)
+        self.added_addresses = set()
+        self.interface = interface
+
+        self._ip = IPRoute()
+        try:
+            self._dev = self._setup_interface()
+        except NetlinkError as ex:
+            raise RuntimeError(f"Couldn't set interface `{self.interface}` up.") from ex
+
+    def _setup_interface(self):
+        """Set up a dummy interface with default route as well as loopback.
+           This is done so the resulting PCAP contains as much of the communication
+           as possible (including ICMP Destination unreachable packets etc.)."""
+
+        # Create and set the interface up.
+        self._ip.link("add", ifname=self.interface, kind="dummy")
+        dev = self._ip.link_lookup(ifname=self.interface)[0]
+        self._ip.link("set", index=dev, state="up")
+
+        # Set up default route for both IPv6 and IPv4
+        self._ip.neigh("add", dst='169.254.1.1', lladdr='21:21:21:21:21:21',
+                       state=ndmsg.states['permanent'], ifindex=dev)
+        self._ip.neigh("add", family=AF_INET6, dst='fe80::1', lladdr='21:21:21:21:21:21',
+                       state=ndmsg.states['permanent'], ifindex=dev)
+        self._ip.addr("add", index=dev, address="169.254.1.2", mask=24)
+        self._ip.route("add", gateway="169.254.1.1", oif=dev)
+        self._ip.route("add", family=AF_INET6, gateway='fe80::1', oif=dev)
+
+        # Set the loopback up as well since some of the packets go through there.
+        lo = self._ip.link_lookup(ifname="lo")[0]
+        self._ip.link("set", index=lo, state="up")
+
+        # Return internal interface ID for later use
+        return dev
+
+    def assign_internal_address(self, sockfamily) -> str:
+        """Add and return new address from the internal range"""
+        try:
+            if sockfamily == AF_INET:
+                a = str(next(self.ip4_iterator))
+            elif sockfamily == AF_INET6:
+                a = str(next(self.ip6_iterator))
+            else:
+                raise ValueError(f"Unknown sockfamily {sockfamily}")
+        except StopIteration as ex:
+            raise RuntimeError("Out of addresses.") from ex
+
+        self._add_address(a)
+        return a
+
+    def add_address(self, address: str, check_duplicate=False):
+        """Add an arbitrary new address to the interface"""
+        if address in self.added_addresses and check_duplicate:
+            raise ValueError(f"Tried to add duplicate address {address}")
+        if ip_address(address) in self.ip4_internal_range or \
+           ip_address(address) in self.ip6_internal_range:
+            raise ValueError(f"Address {address} in the internally reserved range.")
+        self._add_address(address)
+
+    def _add_address(self, address):
+        if ":" in address:
+            mask = 128
+        else:
+            mask = 32
+        try:
+            self._ip.addr("add", index=self._dev, address=address, mask=mask, nodad=True)
+        except NetlinkError as ex:
+            if ex.code != errno.EEXIST:  # 'RTNETLINK answers: File exists' is OK here
+                raise ValueError(f"Couldn't add {address}") from ex
+
+        self.added_addresses.add(address)