MTU: Setting of MTU on software interface (instead of hardware interface)

Change-Id: I98bd454a761a1032738a21edeb0fe847e801f901
Signed-off-by: Ole Troan <ot@cisco.com>

2 files changed, 65 insertions, 7 deletions

diff --git a/test/test_ip4.py b/test/test_ip4.py
index 1a611251eb5..5b5cf09c86f 100644
--- a/test/test_ip4.py
+++ b/test/test_ip4.py
@@ -1294,7 +1294,7 @@ class TestIPInput(VppTestCase):
                        dst=self.pg0.local_mac) /
                  IP(src=self.pg0.remote_ip4,
                     dst=self.pg1.remote_ip4,
-                    ttl=10) /
+                    ttl=10, flags='DF') /
                  UDP(sport=1234, dport=1234) /
                  Raw('\xa5' * 2000))
 
diff --git a/test/test_ipip.py b/test/test_ipip.py
index 3a0c401f8af..dc7b611164f 100644
--- a/test/test_ipip.py
+++ b/test/test_ipip.py
@@ -2,7 +2,8 @@
 """IP{4,6} over IP{v,6} tunnel functional tests"""
 
 import unittest
-from scapy.layers.inet6 import IPv6, Ether, IP, UDP
+from scapy.layers.inet6 import IPv6, Ether, IP, UDP, ICMPv6PacketTooBig
+from scapy.layers.inet import ICMP
 from framework import VppTestCase, VppTestRunner
 from vpp_ip_route import VppIpRoute, VppRoutePath, DpoProto
 from socket import AF_INET, AF_INET6, inet_pton
@@ -44,12 +45,18 @@ class TestIPIP(VppTestCase):
     def validate(self, rx, expected):
         self.assertEqual(rx, expected.__class__(str(expected)))
 
+    def validate_bytes(self, rx, expected):
+        self.assertEqual(rx, expected)
+
+    def payload(self, len):
+        return 'x' * len
+
     def test_ipip4(self):
         """ ip{v4,v6} over ip4 test """
         p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
         p_ip6 = IPv6(src="1::1", dst="DEAD::1", nh='UDP')
-        p_ip4 = IP(src="1.2.3.4", dst="130.67.0.1")
-        p_payload = UDP(sport=1234, dport=1234)
+        p_ip4 = IP(src=self.pg0.remote_ip4, dst="130.67.0.1")
+        p_payload = UDP(sport=1234, dport=1234) / self.payload(1300)
 
         # IPv4 transport
         rv = self.vapi.ipip_add_tunnel(
@@ -98,10 +105,37 @@ class TestIPIP(VppTestCase):
                        dst=self.pg1.remote_ip4) / p_ip4_inner / p_payload)
         p4_reply.ttl -= 1
         p4_reply.id = 0
-        rx = self.send_and_expect(self.pg0, p4*10, self.pg1)
+        rx = self.send_and_expect(self.pg0, p4*11, self.pg1)
         for p in rx:
             self.validate(p[1], p4_reply)
 
+        # MTU (only checked on encap)
+        rv = self.vapi.sw_interface_set_mtu(sw_if_index, 576)
+        rv = self.vapi.sw_interface_dump()
+        for i in rv:
+            if i.sw_if_index == sw_if_index:
+                self.assertEqual(i.mtu, 576)
+                break
+
+        # Should fail. Too large MTU
+        p4.flags = 'DF'
+        p_icmp4 = ICMP(type='dest-unreach', code='fragmentation-needed',
+                       nexthopmtu=576, chksum=0xb6c7)
+        icmp4_reply = (IP(src=self.pg0.local_ip4,
+                          dst=self.pg0.remote_ip4,
+                          ttl=254, len=576, id=0) /
+                       p_icmp4 / p_ip4 / p_payload)
+        icmp4_reply[1].flags = 'DF'
+        n = icmp4_reply.__class__(str(icmp4_reply))
+        s = str(icmp4_reply)
+        icmp4_reply = s[0:576]
+        rx = self.send_and_expect(self.pg0, p4*9, self.pg0)
+        for p in rx:
+            self.validate_bytes(str(p[1]), icmp4_reply)
+
+        # Reset MTU
+        rv = self.vapi.sw_interface_set_mtu(sw_if_index, 1480)
+
         # Decapsulation
         p_ether = Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac)
 
@@ -128,9 +162,9 @@ class TestIPIP(VppTestCase):
     def test_ipip6(self):
         """ ip{v4,v6} over ip6 test """
         p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
-        p_ip6 = IPv6(src="1::1", dst="DEAD::1", nh='UDP')
+        p_ip6 = IPv6(src=self.pg0.remote_ip6, dst="DEAD::1", nh='UDP')
         p_ip4 = IP(src="1.2.3.4", dst="130.67.0.1")
-        p_payload = UDP(sport=1234, dport=1234)
+        p_payload = UDP(sport=1234, dport=1234) / self.payload(1300)
 
         # IPv6 transport
         rv = self.vapi.ipip_add_tunnel(
@@ -169,6 +203,30 @@ class TestIPIP(VppTestCase):
         for p in rx:
             self.validate(p[1], p6_reply)
 
+        # MTU (only checked on encap)
+        rv = self.vapi.sw_interface_set_mtu(sw_if_index, 1280)
+        rv = self.vapi.sw_interface_dump()
+        for i in rv:
+            if i.sw_if_index == sw_if_index:
+                self.assertEqual(i.mtu, 1280)
+                break
+
+        # Should fail. Too large MTU
+        p_icmp6 = ICMPv6PacketTooBig(mtu=1280, cksum=0xd401)
+        icmp6_reply = (IPv6(src=self.pg0.local_ip6,
+                            dst=self.pg0.remote_ip6,
+                            hlim=254, plen=1240) /
+                       p_icmp6 / p_ip6 / p_payload)
+        icmp6_reply[2].hlim -= 1
+        s = str(icmp6_reply)
+        icmp6_reply = s[0:1280]
+        rx = self.send_and_expect(self.pg0, p6*9, self.pg0)
+        for p in rx:
+            self.validate_bytes(str(p[1]), icmp6_reply)
+
+        # Reset MTU
+        rv = self.vapi.sw_interface_set_mtu(sw_if_index, 1460)
+
         # IPv4 in to IPv6 tunnel
         p4 = (p_ether / p_ip4 / p_payload)
         p4_reply = (IPv6(src=self.pg0.local_ip6,