wireguard: sending the first handshake

After creating a peer, we send a handshake request. But it's not quite right
to call wg_send_keepalive() directly.
According to documentation, handshake initiation is sent after (REKEY_TIMEOUT + jitter) ms.
Since it's the first one - we don't need to take REKEY_TIMEOUT into account,
but we still have jitter.

It also makes no sense to immediately send keepalives,
because the connection is not created yet.

Type: fix

Signed-off-by: Artem Glazychev <artem.glazychev@xored.com>
Change-Id: I61707e4be79be65abc3396b5f1dbd48ecbf7ba60

4 files changed, 46 insertions, 10 deletions

diff --git a/src/plugins/wireguard/wireguard_peer.c b/src/plugins/wireguard/wireguard_peer.c
index a8f1ab91644..f7bf2352db4 100644
--- a/src/plugins/wireguard/wireguard_peer.c
+++ b/src/plugins/wireguard/wireguard_peer.c
@@ -244,11 +244,7 @@ wg_peer_enable (vlib_main_t *vm, wg_peer_t *peer)
 
   noise_remote_init (&peer->remote, peeri, public_key, wg_if->local_idx);
 
-  wg_send_handshake (vm, peer, false);
-  if (peer->persistent_keepalive_interval != 0)
-    {
-      wg_send_keepalive (vm, peer);
-    }
+  wg_timers_send_first_handshake (peer);
 }
 
 walk_rc_t
@@ -494,11 +490,7 @@ wg_peer_add (u32 tun_sw_if_index, const u8 public_key[NOISE_PUBLIC_KEY_LEN],
 
   if (vnet_sw_interface_is_admin_up (vnet_get_main (), tun_sw_if_index))
     {
-      wg_send_handshake (vm, peer, false);
-      if (peer->persistent_keepalive_interval != 0)
-	{
-	  wg_send_keepalive (vm, peer);
-	}
+      wg_timers_send_first_handshake (peer);
     }
 
   *peer_index = peer - wg_peer_pool;
diff --git a/src/plugins/wireguard/wireguard_timer.c b/src/plugins/wireguard/wireguard_timer.c
index b95801122fc..4319d534ffc 100644
--- a/src/plugins/wireguard/wireguard_timer.c
+++ b/src/plugins/wireguard/wireguard_timer.c
@@ -239,6 +239,16 @@ wg_timers_handshake_initiated (wg_peer_t * peer)
 }
 
 void
+wg_timers_send_first_handshake (wg_peer_t *peer)
+{
+  // zero value is not allowed
+  peer->new_handshake_interval_tick =
+    get_random_u32_max (REKEY_TIMEOUT_JITTER) + 1;
+  start_timer_from_mt (peer - wg_peer_pool, WG_TIMER_NEW_HANDSHAKE,
+		       peer->new_handshake_interval_tick);
+}
+
+void
 wg_timers_session_derived (wg_peer_t * peer)
 {
   peer->session_derived = vlib_time_now (vlib_get_main ());
diff --git a/src/plugins/wireguard/wireguard_timer.h b/src/plugins/wireguard/wireguard_timer.h
index ebde47e9067..47638bfd74d 100644
--- a/src/plugins/wireguard/wireguard_timer.h
+++ b/src/plugins/wireguard/wireguard_timer.h
@@ -50,6 +50,7 @@ void wg_timers_any_authenticated_packet_received_opt (wg_peer_t *peer,
 						      f64 time);
 void wg_timers_handshake_initiated (wg_peer_t * peer);
 void wg_timers_handshake_complete (wg_peer_t * peer);
+void wg_timers_send_first_handshake (wg_peer_t *peer);
 void wg_timers_session_derived (wg_peer_t * peer);
 void wg_timers_any_authenticated_packet_traversal (wg_peer_t * peer);
 
diff --git a/test/test_wireguard.py b/test/test_wireguard.py
index 80ebdd89aa6..72a317ca8c2 100644
--- a/test/test_wireguard.py
+++ b/test/test_wireguard.py
@@ -147,6 +147,8 @@ UNDER_LOAD_INTERVAL = 1.0
 HANDSHAKE_NUM_PER_PEER_UNTIL_UNDER_LOAD = 40
 HANDSHAKE_NUM_BEFORE_RATELIMITING = 5
 
+HANDSHAKE_JITTER = 0.5
+
 
 class VppWgPeer(VppObject):
     def __init__(self, test, itf, endpoint, port, allowed_ips, persistent_keepalive=15):
@@ -672,6 +674,9 @@ class TestWg(VppTestCase):
         self.assertEqual(len(self.vapi.wireguard_peers_dump()), 1)
 
         if is_resp:
+            # skip the first automatic handshake
+            self.pg1.get_capture(1, timeout=HANDSHAKE_JITTER)
+
             # prepare and send a handshake initiation
             # expect the peer to send a handshake response
             init = peer_1.mk_handshake(self.pg1, is_ip6=is_ip6)
@@ -764,6 +769,9 @@ class TestWg(VppTestCase):
             # reset noise to be able to turn into initiator later
             peer_1.noise_reset()
         else:
+            # skip the first automatic handshake
+            self.pg1.get_capture(1, timeout=HANDSHAKE_JITTER)
+
             # prepare and send a bunch of handshake initiations
             # expect to switch to under load state
             init = peer_1.mk_handshake(self.pg1, is_ip6=is_ip6)
@@ -829,6 +837,9 @@ class TestWg(VppTestCase):
         ).add_vpp_config()
         self.assertEqual(len(self.vapi.wireguard_peers_dump()), 1)
 
+        # skip the first automatic handshake
+        self.pg1.get_capture(1, timeout=HANDSHAKE_JITTER)
+
         # prepare and send a bunch of handshake initiations
         # expect to switch to under load state
         init = peer_1.mk_handshake(self.pg1)
@@ -893,6 +904,9 @@ class TestWg(VppTestCase):
             ).add_vpp_config()
         self.assertEqual(len(self.vapi.wireguard_peers_dump()), 1)
 
+        # skip the first automatic handshake
+        self.pg1.get_capture(1, timeout=HANDSHAKE_JITTER)
+
         # prepare and send a bunch of handshake initiations
         # expect to switch to under load state
         init = peer_1.mk_handshake(self.pg1, is_ip6=is_ip6)
@@ -963,6 +977,9 @@ class TestWg(VppTestCase):
         ).add_vpp_config()
         self.assertEqual(len(self.vapi.wireguard_peers_dump()), 2)
 
+        # skip the first automatic handshake
+        self.pg1.get_capture(NUM_PEERS, timeout=HANDSHAKE_JITTER)
+
         # (peer_1) prepare and send a bunch of handshake initiations
         # expect not to switch to under load state
         init_1 = peer_1.mk_handshake(self.pg1)
@@ -2098,6 +2115,9 @@ class TestWg(VppTestCase):
         self.pg0.generate_remote_hosts(NUM_IFS)
         self.pg0.configure_ipv4_neighbors()
 
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
         # Create interfaces with a peer on each
         peers = []
         routes = []
@@ -2129,6 +2149,9 @@ class TestWg(VppTestCase):
 
         self.assertEqual(len(self.vapi.wireguard_peers_dump()), NUM_IFS)
 
+        # skip the first automatic handshake
+        self.pg1.get_capture(NUM_IFS, timeout=HANDSHAKE_JITTER)
+
         for i in range(NUM_IFS):
             # send a valid handsake init for which we expect a response
             p = peers[i].mk_handshake(self.pg1)
@@ -2282,6 +2305,10 @@ class TestWg(VppTestCase):
 
         self.assertEqual(len(self.vapi.wireguard_peers_dump()), NUM_PEERS * 2)
 
+        # skip the first automatic handshake
+        self.pg1.get_capture(NUM_PEERS, timeout=HANDSHAKE_JITTER)
+        self.pg2.get_capture(NUM_PEERS, timeout=HANDSHAKE_JITTER)
+
         # Want events from the first perr of wg0
         # and from all wg1 peers
         peers_0[0].want_events()
@@ -2472,6 +2499,9 @@ class WireguardHandoffTests(TestWg):
         wg0.admin_up()
         wg0.config_ip4()
 
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
         peer_1 = VppWgPeer(
             self, wg0, self.pg1.remote_ip4, port + 1, ["10.11.2.0/24", "10.11.3.0/24"]
         ).add_vpp_config()
@@ -2481,6 +2511,9 @@ class WireguardHandoffTests(TestWg):
             self, "10.11.3.0", 24, [VppRoutePath("10.11.3.1", wg0.sw_if_index)]
         ).add_vpp_config()
 
+        # skip the first automatic handshake
+        self.pg1.get_capture(1, timeout=HANDSHAKE_JITTER)
+
         # send a valid handsake init for which we expect a response
         p = peer_1.mk_handshake(self.pg1)