ip: Fixes for IPv6 and MPLS fragmentation

Type: fix

- IPv6 fragmentation did not work if the packet spaneed multiple buffers, because the 'len' calculation to did max out at the size of a buffer
- IPv6 fragmentation did not work when the l2unfragmentable size was non-zero, it was not used in the correct places
- IPv6oMPLS fragmentation would fragment all IPv6, it should do so only for link local
- IPv6oMPLS should send back TooBig ICMP6 for non locally generated

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: Ie8f02cdfdd7b7e8474e62b6d0acda8f20c371184

1 files changed, 55 insertions, 1 deletions

diff --git a/test/test_mpls.py b/test/test_mpls.py
index 4cc7a0759f2..d94676b67da 100644
--- a/test/test_mpls.py
+++ b/test/test_mpls.py
@@ -18,7 +18,8 @@ import scapy.compat
 from scapy.packet import Raw
 from scapy.layers.l2 import Ether, ARP
 from scapy.layers.inet import IP, UDP, ICMP
-from scapy.layers.inet6 import IPv6, ICMPv6TimeExceeded, ICMPv6EchoRequest
+from scapy.layers.inet6 import IPv6, ICMPv6TimeExceeded, ICMPv6EchoRequest, \
+    ICMPv6PacketTooBig
 from scapy.contrib.mpls import MPLS
 
 NUM_PKTS = 67
@@ -425,6 +426,31 @@ class TestMPLS(VppTestCase):
         except:
             raise
 
+    def verify_capture_fragmented_labelled_ip6(self, src_if, capture, sent,
+                                               mpls_labels, ip_ttl=None):
+        try:
+            capture = verify_filter(capture, sent)
+
+            for i in range(len(capture)):
+                tx = sent[0]
+                rx = capture[i]
+                tx_ip = tx[IPv6]
+                rx.show()
+                rx_ip = IPv6(rx[MPLS].payload)
+                rx_ip.show()
+
+                verify_mpls_stack(self, rx, mpls_labels)
+
+                self.assertEqual(rx_ip.src, tx_ip.src)
+                self.assertEqual(rx_ip.dst, tx_ip.dst)
+                if not ip_ttl:
+                    # IP processing post pop has decremented the hop-limit
+                    self.assertEqual(rx_ip.hlim + 1, tx_ip.hlim)
+                else:
+                    self.assertEqual(rx_ip.hlim, ip_ttl)
+        except:
+            raise
+
     def test_swap(self):
         """ MPLS label swap tests """
 
@@ -908,6 +934,11 @@ class TestMPLS(VppTestCase):
                                                   self.pg0.sw_if_index,
                                                   labels=[VppMplsLabel(32)])])
         route_10_0_0_1.add_vpp_config()
+        route_1000_1 = VppIpRoute(self, "1000::1", 128,
+                                  [VppRoutePath(self.pg0.remote_ip6,
+                                                self.pg0.sw_if_index,
+                                                labels=[VppMplsLabel(32)])])
+        route_1000_1.add_vpp_config()
 
         #
         # a stream that matches the route for 10.0.0.1
@@ -924,6 +955,29 @@ class TestMPLS(VppTestCase):
         self.verify_capture_fragmented_labelled_ip4(self.pg0, rx, tx,
                                                     [VppMplsLabel(32)])
 
+        # packets with DF bit set generate ICMP
+        for t in tx:
+            t[IP].flags = 'DF'
+        rxs = self.send_and_expect_some(self.pg0, tx, self.pg0)
+
+        for rx in rxs:
+            rx[ICMP].code = "fragmentation-needed"
+
+        self.assertEqual(self.statistics.get_err_counter(
+            "/err/mpls-frag/can't fragment this packet"),
+                         len(tx))
+        #
+        # a stream that matches the route for 1000::1/128
+        # PG0 is in the default table
+        #
+        tx = self.create_stream_ip6(self.pg0, "1000::1")
+        for i in range(0, 257):
+            self.extend_packet(tx[i], 10000)
+
+        rxs = self.send_and_expect_some(self.pg0, tx, self.pg0)
+        for rx in rxs:
+            rx[ICMPv6PacketTooBig].mtu = 9000
+
         #
         # cleanup
         #