packet/bgp: Fix data structure for VPNv4 Flow Specification

The Route Distinguisher did not include in data structure
for VPNv4 Flow Specification.
This patch adds the Route Distinguisher to data structure
for VPNv4 Flow Specification.
For details, refer to Chapter 8 of RFC 5575.

Signed-off-by: Shinpei Muraoka <shinpei.muraoka@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

4 files changed, 78 insertions, 15 deletions

diff --git a/ryu/lib/packet/bgp.py b/ryu/lib/packet/bgp.py
index 47feeb39..d22bb0ed 100644
--- a/ryu/lib/packet/bgp.py
+++ b/ryu/lib/packet/bgp.py
@@ -1997,7 +1997,7 @@ class _FlowSpecNLRIBase(StringifyMixin, TypeDisp):
     # +-----------------------------------+
     # |     NLRI value  (variable)        |
     # +-----------------------------------+
-
+    ROUTE_FAMILY = None
     _LENGTH_SHORT_FMT = '!B'
     LENGTH_SHORT_SIZE = struct.calcsize(_LENGTH_SHORT_FMT)
     _LENGTH_LONG_FMT = '!H'
@@ -2013,7 +2013,7 @@ class _FlowSpecNLRIBase(StringifyMixin, TypeDisp):
 
     @classmethod
     def parser(cls, buf):
-        (length, ) = struct.unpack_from(
+        (length,) = struct.unpack_from(
             cls._LENGTH_LONG_FMT, six.binary_type(buf))
 
         if length < cls._LENGTH_THRESHOLD:
@@ -2022,7 +2022,14 @@ class _FlowSpecNLRIBase(StringifyMixin, TypeDisp):
         else:
             offset = cls.LENGTH_LONG_SIZE
 
+        kwargs = {'length': length}
         rest = buf[offset:offset + length]
+
+        if cls.ROUTE_FAMILY.safi == subaddr_family.VPN_FLOW_SPEC:
+            route_dist = _RouteDistinguisher.parser(rest[:8])
+            kwargs['route_dist'] = route_dist.formatted_str
+            rest = rest[8:]
+
         rules = []
 
         while rest:
@@ -2036,10 +2043,17 @@ class _FlowSpecNLRIBase(StringifyMixin, TypeDisp):
                         rule.operator & rule.END_OF_LIST):
                     break
 
-        return cls(length, rules), rest
+        kwargs['rules'] = rules
+
+        return cls(**kwargs), rest
 
     def serialize(self):
-        rules_bin = bytearray()
+        rules_bin = b''
+
+        if self.ROUTE_FAMILY.safi == subaddr_family.VPN_FLOW_SPEC:
+            route_dist = _RouteDistinguisher.from_str(self.route_dist)
+            rules_bin += route_dist.serialize()
+
         self.rules.sort(key=lambda x: x.type)
         for _, rules in itertools.groupby(self.rules, key=lambda x: x.type):
             rules = list(rules)
@@ -2114,18 +2128,19 @@ class FlowSpecIPv4NLRI(_FlowSpecNLRIBase):
         =========== ============= ========= ==============================
 
         Example::
+
             >>> msg = bgp.FlowSpecIPv4NLRI.from_user(
             ...     dst_prefix='10.0.0.0/24',
             ...     src_prefix='20.0.0.1/24',
-            ...     ip_proto='==6',
-            ...     port='==80 | ==8000',
+            ...     ip_proto=6,
+            ...     port='80 | 8000',
             ...     dst_port='>9000 & <9050',
             ...     src_port='>=8500 & <=9000',
-            ...     icmp_type='==0',
-            ...     icmp_code='==6',
+            ...     icmp_type=0,
+            ...     icmp_code=6,
             ...     tcp_flags='SYN+ACK & !=URGENT',
-            ...     packet_len='==1000',
-            ...     dscp='==22 | ==24',
+            ...     packet_len=1000,
+            ...     dscp='22 | 24',
             ...     fragment='LF | ==FF')
             >>>
 
@@ -2173,15 +2188,62 @@ class FlowSpecIPv4NLRI(_FlowSpecNLRIBase):
 class FlowSpecVPNv4NLRI(_FlowSpecNLRIBase):
     """
     Flow Specification NLRI class for VPNv4 [RFC 5575]
-
-    See :py:mod:`ryu.lib.packet.bgp.FlowSpecIPv4NLRI`
     """
+
+    # flow-spec NLRI:
+    # +-----------------------------------+
+    # |    length (0xnn or 0xfn nn)       |
+    # +-----------------------------------+
+    # |     RD   (8 octets)               |
+    # +-----------------------------------+
+    # |     NLRI value  (variable)        |
+    # +-----------------------------------+
     ROUTE_FAMILY = RF_VPNv4_FLOW_SPEC
 
+    def __init__(self, length=0, route_dist=None, rules=None):
+        super(FlowSpecVPNv4NLRI, self).__init__(length, rules)
+        assert route_dist is not None
+        self.route_dist = route_dist
+
     @classmethod
-    def from_user(cls, **kwargs):
+    def _from_user(cls, route_dist, **kwargs):
+        rules = []
+        for k, v in kwargs.items():
+            subcls = _FlowSpecComponentBase.lookup_type_name(k)
+            rule = subcls.from_str(str(v))
+            rules.extend(rule)
+        rules.sort(key=lambda x: x.type)
+        return cls(route_dist=route_dist, rules=rules)
 
-        return cls._from_user(**kwargs)
+    @classmethod
+    def from_user(cls, route_dist, **kwargs):
+        """
+        Utility method for creating a NLRI instance.
+
+        This function returns a NLRI instance from human readable format value.
+
+        :param route_dist: Route Distinguisher.
+        :param kwargs: See :py:mod:`ryu.lib.packet.bgp.FlowSpecIPv4NLRI`
+
+        Example::
+
+            >>> msg = bgp.FlowSpecIPv4NLRI.from_user(
+            ...     route_dist='65000:1000',
+            ...     dst_prefix='10.0.0.0/24',
+            ...     src_prefix='20.0.0.1/24',
+            ...     ip_proto=6,
+            ...     port='80 | 8000',
+            ...     dst_port='>9000 & <9050',
+            ...     src_port='>=8500 & <=9000',
+            ...     icmp_type=0,
+            ...     icmp_code=6,
+            ...     tcp_flags='SYN+ACK & !=URGENT',
+            ...     packet_len=1000,
+            ...     dscp='22 | 24',
+            ...     fragment='LF | ==FF')
+            >>>
+        """
+        return cls._from_user(route_dist, **kwargs)
 
 
 class _FlowSpecComponentBase(StringifyMixin, TypeDisp):
diff --git a/ryu/tests/packet_data/bgp4/flowspec_nlri_ipv4.pcap b/ryu/tests/packet_data/bgp4/flowspec_nlri_ipv4.pcap
index c7953484..885a106a 100644
--- a/ryu/tests/packet_data/bgp4/flowspec_nlri_ipv4.pcap
+++ b/ryu/tests/packet_data/bgp4/flowspec_nlri_ipv4.pcap
diff --git a/ryu/tests/packet_data/bgp4/flowspec_nlri_vpn4.pcap b/ryu/tests/packet_data/bgp4/flowspec_nlri_vpn4.pcap
index 74a7d174..236110db 100644
--- a/ryu/tests/packet_data/bgp4/flowspec_nlri_vpn4.pcap
+++ b/ryu/tests/packet_data/bgp4/flowspec_nlri_vpn4.pcap
diff --git a/ryu/tests/unit/packet/test_bgp.py b/ryu/tests/unit/packet/test_bgp.py
index dec1dae6..a3b7a68f 100644
--- a/ryu/tests/unit/packet/test_bgp.py
+++ b/ryu/tests/unit/packet/test_bgp.py
@@ -561,6 +561,7 @@ class Test_bgp(unittest.TestCase):
         eq_(rest, b'')
 
         msg = bgp.FlowSpecVPNv4NLRI.from_user(
+            route_dist='65001:250',
             dst_prefix='10.0.0.0/24',
             src_prefix='20.0.0.0/24',
             ip_proto='6',
@@ -573,7 +574,7 @@ class Test_bgp(unittest.TestCase):
             packet_len='1000 & 1100',
             dscp='22 24',
             fragment='LF ==FF&==ISF | !=DF')
-        msg2 = bgp.FlowSpecVPNv4NLRI(rules=rules)
+        msg2 = bgp.FlowSpecVPNv4NLRI(route_dist='65001:250', rules=rules)
         binmsg = msg.serialize()
         binmsg2 = msg2.serialize()
         eq_(str(msg), str(msg2))