wireguard: add support for chained buffers

Type: feature

With this change, packets that are larger than a single buffer can fit
will be able to be sent and received over a Wireguard tunnel. Also,
cover this with tests.

Signed-off-by: Alexander Chernavin <achernavin@netgate.com>
Change-Id: Ifaf7325676d728580097bc389b51a9be39e44d88

1 files changed, 227 insertions, 0 deletions

diff --git a/test/test_wireguard.py b/test/test_wireguard.py
index b9713f6fc08..e63508af459 100644
--- a/test/test_wireguard.py
+++ b/test/test_wireguard.py
@@ -11,6 +11,7 @@ from scapy.packet import Raw
 from scapy.layers.l2 import Ether, ARP
 from scapy.layers.inet import IP, UDP
 from scapy.layers.inet6 import IPv6
+from scapy.layers.vxlan import VXLAN
 from scapy.contrib.wireguard import (
     Wireguard,
     WireguardResponse,
@@ -40,6 +41,8 @@ from vpp_ipip_tun_interface import VppIpIpTunInterface
 from vpp_interface import VppInterface
 from vpp_pg_interface import is_ipv6_misc
 from vpp_ip_route import VppIpRoute, VppRoutePath
+from vpp_l2 import VppBridgeDomain, VppBridgeDomainPort
+from vpp_vxlan_tunnel import VppVxlanTunnel
 from vpp_object import VppObject
 from vpp_papi import VppEnum
 from framework import is_distro_ubuntu2204, is_distro_debian11, tag_fixme_vpp_debug
@@ -470,6 +473,7 @@ class VppWgPeer(VppObject):
         return self.noise.encrypt(bytes(p))
 
     def validate_encapped(self, rxs, tx, is_tunnel_ip6=False, is_transport_ip6=False):
+        ret_rxs = []
         for rx in rxs:
             rx = self.decrypt_transport(rx, is_tunnel_ip6)
             if is_transport_ip6 is False:
@@ -482,6 +486,8 @@ class VppWgPeer(VppObject):
                 # check the original packet is present
                 self._test.assertEqual(rx[IPv6].dst, tx[IPv6].dst)
                 self._test.assertEqual(rx[IPv6].hlim, tx[IPv6].hlim - 1)
+            ret_rxs.append(rx)
+        return ret_rxs
 
     def want_events(self):
         self._test.vapi.want_wireguard_peer_events(
@@ -2510,6 +2516,227 @@ class TestWg(VppTestCase):
         peer_1.remove_vpp_config()
         wg0.remove_vpp_config()
 
+    def _test_wg_large_packet_tmpl(self, is_async, is_ip6):
+        self.vapi.wg_set_async_mode(is_async)
+        port = 12323
+
+        # create wg interface
+        if is_ip6:
+            wg0 = VppWgInterface(self, self.pg1.local_ip6, port).add_vpp_config()
+            wg0.admin_up()
+            wg0.config_ip6()
+        else:
+            wg0 = VppWgInterface(self, self.pg1.local_ip4, port).add_vpp_config()
+            wg0.admin_up()
+            wg0.config_ip4()
+
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        # create a peer
+        if is_ip6:
+            peer_1 = VppWgPeer(
+                self, wg0, self.pg1.remote_ip6, port + 1, ["1::3:0/112"]
+            ).add_vpp_config()
+        else:
+            peer_1 = VppWgPeer(
+                self, wg0, self.pg1.remote_ip4, port + 1, ["10.11.3.0/24"]
+            ).add_vpp_config()
+        self.assertEqual(len(self.vapi.wireguard_peers_dump()), 1)
+
+        # create a route to rewrite traffic into the wg interface
+        if is_ip6:
+            r1 = VppIpRoute(
+                self, "1::3:0", 112, [VppRoutePath("1::3:1", wg0.sw_if_index)]
+            ).add_vpp_config()
+        else:
+            r1 = VppIpRoute(
+                self, "10.11.3.0", 24, [VppRoutePath("10.11.3.1", wg0.sw_if_index)]
+            ).add_vpp_config()
+
+        # wait for the peer to send a handshake initiation
+        rxs = self.pg1.get_capture(1, timeout=2)
+
+        # prepare and send a handshake response
+        # expect a keepalive message
+        resp = peer_1.consume_init(rxs[0], self.pg1, is_ip6=is_ip6)
+        rxs = self.send_and_expect(self.pg1, [resp], self.pg1)
+
+        # verify the keepalive message
+        b = peer_1.decrypt_transport(rxs[0], is_ip6=is_ip6)
+        self.assertEqual(0, len(b))
+
+        # prepare and send data packets
+        # expect to receive them decrypted
+        if is_ip6:
+            ip_header = IPv6(src="1::3:1", dst=self.pg0.remote_ip6, hlim=20)
+        else:
+            ip_header = IP(src="10.11.3.1", dst=self.pg0.remote_ip4, ttl=20)
+        packet_len_opts = (
+            2500,  # two buffers
+            1500,  # one buffer
+            4500,  # three buffers
+            1910 if is_ip6 else 1950,  # auth tag is not contiguous
+        )
+        txs = []
+        for l in packet_len_opts:
+            txs.append(
+                peer_1.mk_tunnel_header(self.pg1, is_ip6=is_ip6)
+                / Wireguard(message_type=4, reserved_zero=0)
+                / WireguardTransport(
+                    receiver_index=peer_1.sender,
+                    counter=len(txs),
+                    encrypted_encapsulated_packet=peer_1.encrypt_transport(
+                        ip_header / UDP(sport=222, dport=223) / Raw(b"\xfe" * l)
+                    ),
+                )
+            )
+        rxs = self.send_and_expect(self.pg1, txs, self.pg0)
+
+        # verify decrypted packets
+        for i, l in enumerate(packet_len_opts):
+            if is_ip6:
+                self.assertEqual(rxs[i][IPv6].dst, self.pg0.remote_ip6)
+                self.assertEqual(rxs[i][IPv6].hlim, ip_header.hlim - 1)
+            else:
+                self.assertEqual(rxs[i][IP].dst, self.pg0.remote_ip4)
+                self.assertEqual(rxs[i][IP].ttl, ip_header.ttl - 1)
+            self.assertEqual(len(rxs[i][Raw]), l)
+            self.assertEqual(bytes(rxs[i][Raw]), b"\xfe" * l)
+
+        # prepare and send packets that will be rewritten into the wg interface
+        # expect data packets sent
+        if is_ip6:
+            ip_header = IPv6(src=self.pg0.remote_ip6, dst="1::3:2")
+        else:
+            ip_header = IP(src=self.pg0.remote_ip4, dst="10.11.3.2")
+        packet_len_opts = (
+            2500,  # two buffers
+            1500,  # one buffer
+            4500,  # three buffers
+            1980 if is_ip6 else 2000,  # no free space to write auth tag
+        )
+        txs = []
+        for l in packet_len_opts:
+            txs.append(
+                Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
+                / ip_header
+                / UDP(sport=555, dport=556)
+                / Raw(b"\xfe" * l)
+            )
+        rxs = self.send_and_expect(self.pg0, txs, self.pg1)
+
+        # verify the data packets
+        rxs_decrypted = peer_1.validate_encapped(
+            rxs, ip_header, is_tunnel_ip6=is_ip6, is_transport_ip6=is_ip6
+        )
+
+        for i, l in enumerate(packet_len_opts):
+            self.assertEqual(len(rxs_decrypted[i][Raw]), l)
+            self.assertEqual(bytes(rxs_decrypted[i][Raw]), b"\xfe" * l)
+
+        # remove configs
+        r1.remove_vpp_config()
+        peer_1.remove_vpp_config()
+        wg0.remove_vpp_config()
+
+    def test_wg_large_packet_v4_sync(self):
+        """Large packet (v4, sync)"""
+        self._test_wg_large_packet_tmpl(is_async=False, is_ip6=False)
+
+    def test_wg_large_packet_v6_sync(self):
+        """Large packet (v6, sync)"""
+        self._test_wg_large_packet_tmpl(is_async=False, is_ip6=True)
+
+    def test_wg_large_packet_v4_async(self):
+        """Large packet (v4, async)"""
+        self._test_wg_large_packet_tmpl(is_async=True, is_ip6=False)
+
+    def test_wg_large_packet_v6_async(self):
+        """Large packet (v6, async)"""
+        self._test_wg_large_packet_tmpl(is_async=True, is_ip6=True)
+
+    def test_wg_lack_of_buf_headroom(self):
+        """Lack of buffer's headroom (v6 vxlan over v6 wg)"""
+        port = 12323
+
+        # create wg interface
+        wg0 = VppWgInterface(self, self.pg1.local_ip6, port).add_vpp_config()
+        wg0.admin_up()
+        wg0.config_ip6()
+
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        # create a peer
+        peer_1 = VppWgPeer(
+            self, wg0, self.pg1.remote_ip6, port + 1, ["::/0"]
+        ).add_vpp_config()
+        self.assertEqual(len(self.vapi.wireguard_peers_dump()), 1)
+
+        # create a route to enable communication between wg interface addresses
+        r1 = VppIpRoute(
+            self, wg0.remote_ip6, 128, [VppRoutePath("0.0.0.0", wg0.sw_if_index)]
+        ).add_vpp_config()
+
+        # wait for the peer to send a handshake initiation
+        rxs = self.pg1.get_capture(1, timeout=2)
+
+        # prepare and send a handshake response
+        # expect a keepalive message
+        resp = peer_1.consume_init(rxs[0], self.pg1, is_ip6=True)
+        rxs = self.send_and_expect(self.pg1, [resp], self.pg1)
+
+        # verify the keepalive message
+        b = peer_1.decrypt_transport(rxs[0], is_ip6=True)
+        self.assertEqual(0, len(b))
+
+        # create vxlan interface over the wg interface
+        vxlan0 = VppVxlanTunnel(self, src=wg0.local_ip6, dst=wg0.remote_ip6, vni=1111)
+        vxlan0.add_vpp_config()
+
+        # create bridge domain
+        bd1 = VppBridgeDomain(self, bd_id=1)
+        bd1.add_vpp_config()
+
+        # add the vxlan interface and pg0 to the bridge domain
+        bd1_ports = (
+            VppBridgeDomainPort(self, bd1, vxlan0).add_vpp_config(),
+            VppBridgeDomainPort(self, bd1, self.pg0).add_vpp_config(),
+        )
+
+        # prepare and send packets that will be rewritten into the vxlan interface
+        # expect they to be rewritten into the wg interface then and data packets sent
+        tx = (
+            Ether(dst="00:00:00:00:00:01", src="00:00:00:00:00:02")
+            / IPv6(src="::1", dst="::2", hlim=20)
+            / UDP(sport=1111, dport=1112)
+            / Raw(b"\xfe" * 1900)
+        )
+        rxs = self.send_and_expect(self.pg0, [tx] * 5, self.pg1)
+
+        # verify the data packet
+        for rx in rxs:
+            rx_decrypted = IPv6(peer_1.decrypt_transport(rx, is_ip6=True))
+
+            self.assertEqual(rx_decrypted[VXLAN].vni, vxlan0.vni)
+            inner = rx_decrypted[VXLAN].payload
+
+            # check the original packet is present
+            self.assertEqual(inner[IPv6].dst, tx[IPv6].dst)
+            self.assertEqual(inner[IPv6].hlim, tx[IPv6].hlim)
+            self.assertEqual(len(inner[Raw]), len(tx[Raw]))
+            self.assertEqual(bytes(inner[Raw]), bytes(tx[Raw]))
+
+        # remove configs
+        for bdp in bd1_ports:
+            bdp.remove_vpp_config()
+        bd1.remove_vpp_config()
+        vxlan0.remove_vpp_config()
+        r1.remove_vpp_config()
+        peer_1.remove_vpp_config()
+        wg0.remove_vpp_config()
+
 
 @tag_fixme_vpp_debug
 class WireguardHandoffTests(TestWg):