l2: fix vxlan src port entropy with mpls payload

l2 tunnels like vxlan, gtpu, geneva use vnet_l2_compute_flow_hash() to
compute flow hash for udp src port entropy. In case of inner mpls tunnels
to the same lsr ethernet src and dst macs are the same, so l2 flow hash
is also the same leading to no src port entropy and the only rss queue
overflow on receiver side.

Fix it for all the possible vnet_l2_compute_flow_hash callers by making
mpls playload hash in additon to ip4/ip6. Visible performance impact is
not expected as it's only one check for mpls ethertype for common cases.

Type: fix
Signed-off-by: Vladislav Grishenko <themiron@yandex-team.ru>
Change-Id: I69153d42fb3d7c094a670c674fac8d14039c626a

src/vnet/l2/l2_input.h

@@ -27,6 +27,7 @@
 #include <vnet/ethernet/packet.h>
 #include <vnet/ip/ip4_inlines.h>
 #include <vnet/ip/ip6_inlines.h>
+#include <vnet/mpls/mpls_lookup.h>
 
 /* l2 connection type */
 typedef enum l2_input_flags_t_
@@ -327,7 +328,7 @@ vnet_update_l2_len (vlib_buffer_t *b)
 
 /*
  * Compute flow hash of an ethernet packet, use 5-tuple hash if L3 packet
- * is ip4 or ip6. Otherwise hash on smac/dmac/etype.
+ * is ip4, ip6, or mpls. Otherwise hash on smac/dmac/etype.
  * The vlib buffer current pointer is expected to be at ethernet header
  * and vnet l2.l2_len is expected to be setup already.
  */
@@ -342,6 +343,9 @@ vnet_l2_compute_flow_hash (vlib_buffer_t * b)
     return ip4_compute_flow_hash ((ip4_header_t *) l3h, IP_FLOW_HASH_DEFAULT);
   else if (ethertype == ETHERNET_TYPE_IP6)
     return ip6_compute_flow_hash ((ip6_header_t *) l3h, IP_FLOW_HASH_DEFAULT);
+  else if (ethertype == ETHERNET_TYPE_MPLS)
+    return mpls_compute_flow_hash ((mpls_unicast_header_t *) l3h,
+				   IP_FLOW_HASH_DEFAULT);
   else
     {
       u32 a, b, c;

test/template_bd.py

@@ -5,6 +5,8 @@ import abc
 from scapy.layers.l2 import Ether
 from scapy.packet import Raw
 from scapy.layers.inet import IP, UDP
+from scapy.layers.inet6 import IPv6
+from scapy.contrib.mpls import MPLS
 
 
 class BridgeDomain(metaclass=abc.ABCMeta):
@@ -61,8 +63,16 @@ class BridgeDomain(metaclass=abc.ABCMeta):
         """
         self.assertEqual(pkt1[Ether].src, pkt2[Ether].src)
         self.assertEqual(pkt1[Ether].dst, pkt2[Ether].dst)
-        self.assertEqual(pkt1[IP].src, pkt2[IP].src)
+        if MPLS in pkt1 or MPLS in pkt2:
-        self.assertEqual(pkt1[IP].dst, pkt2[IP].dst)
+            self.assertEqual(pkt1[MPLS].label, pkt2[MPLS].label)
+            self.assertEqual(pkt1[MPLS].cos, pkt2[MPLS].cos)
+            self.assertEqual(pkt1[MPLS].ttl, pkt2[MPLS].ttl)
+        if IP in pkt1 or IP in pkt2:
+            self.assertEqual(pkt1[IP].src, pkt2[IP].src)
+            self.assertEqual(pkt1[IP].dst, pkt2[IP].dst)
+        elif IPv6 in pkt1 or IPv6 in pkt2:
+            self.assertEqual(pkt1[IPv6].src, pkt2[IPv6].src)
+            self.assertEqual(pkt1[IPv6].dst, pkt2[IPv6].dst)
         self.assertEqual(pkt1[UDP].sport, pkt2[UDP].sport)
         self.assertEqual(pkt1[UDP].dport, pkt2[UDP].dport)
         self.assertEqual(pkt1[Raw], pkt2[Raw])

test/test_vxlan.py

@@ -11,7 +11,9 @@ from scapy.layers.l2 import Ether
 from scapy.layers.l2 import ARP
 from scapy.packet import Raw, bind_layers
 from scapy.layers.inet import IP, UDP
+from scapy.layers.inet6 import IPv6
 from scapy.layers.vxlan import VXLAN
+from scapy.contrib.mpls import MPLS
 
 import util
 from vpp_ip_route import VppIpRoute, VppRoutePath
@@ -287,6 +289,71 @@ class TestVxlan(BridgeDomain, VppTestCase):
         # Set scapy listen custom port for VxLAN
         bind_layers(UDP, VXLAN, dport=self.dport)
 
+    def encap_packets(self):
+        def encap_frames(frame, n=10):
+            frames = []
+
+            # Provide IP flow hash difference.
+            for i in range(n):
+                p = frame.copy()
+                p[UDP].dport += i
+                frames.append(p)
+
+            self.pg1.add_stream(frames)
+
+            self.pg0.enable_capture()
+            self.pg_start()
+
+            # Pick received frames and check if they're correctly encapsulated.
+            out = self.pg0.get_capture(n)
+            sports = set()
+            for i in range(n):
+                pkt = out[i]
+                self.check_encapsulation(pkt, self.single_tunnel_vni)
+
+                payload = self.decapsulate(pkt)
+                self.assert_eq_pkts(payload, frames[i])
+
+                sports.add(pkt[UDP].sport)
+
+            # Check src port randomization presence, not concerned with the
+            # src ports split ratio, just as long as there are more then one.
+            self.assertGreaterEqual(len(sports), min(n, 2))
+
+        frame_ip4 = (
+            Ether(src="00:00:00:00:00:02", dst="00:00:00:00:00:01")
+            / IP(src="4.3.2.1", dst="1.2.3.4")
+            / UDP(sport=20000, dport=10000)
+            / Raw("\xa5" * 100)
+        )
+        encap_frames(frame_ip4)
+
+        frame_ip6 = (
+            Ether(src="00:00:00:00:00:02", dst="00:00:00:00:00:01")
+            / IPv6(src="2001:db8::4321", dst="2001:db8::1234")
+            / UDP(sport=20000, dport=10000)
+            / Raw("\xa5" * 100)
+        )
+        encap_frames(frame_ip6)
+
+        frame_mpls4 = (
+            Ether(src="00:00:00:00:00:02", dst="00:00:00:00:00:01")
+            / MPLS(label=44, ttl=64)
+            / IP(src="4.3.2.1", dst="1.2.3.4")
+            / UDP(sport=20000, dport=10000)
+            / Raw("\xa5" * 100)
+        )
+        encap_frames(frame_mpls4)
+
+        frame_mpls6 = (
+            Ether(src="00:00:00:00:00:02", dst="00:00:00:00:00:01")
+            / MPLS(label=44, ttl=64)
+            / IPv6(src="2001:db8::4321", dst="2001:db8::1234")
+            / UDP(sport=20000, dport=10000)
+            / Raw("\xa5" * 100)
+        )
+        encap_frames(frame_mpls6)
+
     def encap_big_packet(self):
         self.vapi.sw_interface_set_mtu(self.pg0.sw_if_index, [1500, 0, 0, 0])
 
@@ -330,7 +397,7 @@ class TestVxlan(BridgeDomain, VppTestCase):
         from BridgeDoman
         """
         self.createVxLANInterfaces()
-        super(TestVxlan, self).test_encap()
+        self.encap_packets()
 
     def test_encap_big_packet(self):
         """Encapsulation test send big frame from pg1