packet/zebra: Support IP_ROUTE message from Zebra

Zebra IPv4/IPv6 route message have asymmetric structure, in other words,
the message structure from Zebra to the protocol daemons and that from
the protocol daemons to Zebra have the different structures.

This patch introduces _ZebraMessageFromZebra in order to distinguish
which daemon sent the message and fixes _ZebraIPRoute to decode IPv4/IPv6
route message from Zebra.

Signed-off-by: IWASE Yusuke <iwase.yusuke0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

3 files changed, 164 insertions, 23 deletions

diff --git a/ryu/lib/packet/tcp.py b/ryu/lib/packet/tcp.py
index e264f6db..4b7dfe2e 100644
--- a/ryu/lib/packet/tcp.py
+++ b/ryu/lib/packet/tcp.py
@@ -120,7 +120,9 @@ class tcp(packet_base.PacketBase):
         elif(src_port in [OFP_TCP_PORT, OFP_SSL_PORT_OLD] or
              dst_port in [OFP_TCP_PORT, OFP_SSL_PORT_OLD]):
             return openflow.openflow
-        elif zebra.ZEBRA_PORT in [src_port, dst_port]:
+        elif src_port == zebra.ZEBRA_PORT:
+            return zebra._ZebraMessageFromZebra
+        elif dst_port == zebra.ZEBRA_PORT:
             return zebra.ZebraMessage
         else:
             return None
diff --git a/ryu/lib/packet/zebra.py b/ryu/lib/packet/zebra.py
index fec37b42..2858e053 100644
--- a/ryu/lib/packet/zebra.py
+++ b/ryu/lib/packet/zebra.py
@@ -33,6 +33,7 @@ from ryu.lib import stringify
 from ryu.lib import type_desc
 from . import packet_base
 from . import bgp
+from . import safi as packet_safi
 
 
 LOG = logging.getLogger(__name__)
@@ -774,14 +775,15 @@ class ZebraMessage(packet_base.PacketBase):
             'marker=%d, version=%d' % (marker, version))
 
     @classmethod
-    def parser(cls, buf):
+    def _parser_impl(cls, buf, body_parser='parse'):
         buf = six.binary_type(buf)
         (length, version, vrf_id, command,
          body_buf) = cls.parse_header(buf)
 
         if body_buf:
             body_cls = _ZebraMessageBody.lookup_command(command)
-            body = body_cls.parse(body_buf)
+            _parser = getattr(body_cls, body_parser)
+            body = _parser(body_buf)
         else:
             body = None
 
@@ -789,6 +791,10 @@ class ZebraMessage(packet_base.PacketBase):
 
         return cls(length, version, vrf_id, command, body), cls, rest
 
+    @classmethod
+    def parser(cls, buf):
+        return cls._parser_impl(buf)
+
     def serialize_header(self, body_len):
         if self.version == 0:
             self.length = self.V0_HEADER_SIZE + body_len  # fixup
@@ -821,6 +827,16 @@ class ZebraMessage(packet_base.PacketBase):
         return self.serialize_header(len(body)) + body
 
 
+class _ZebraMessageFromZebra(ZebraMessage):
+    """
+    This class is corresponding to the message sent from Zebra daemon.
+    """
+
+    @classmethod
+    def parser(cls, buf):
+        return cls._parser_impl(buf, body_parser='parse_from_zebra')
+
+
 # Alias
 zebra = ZebraMessage
 
@@ -844,6 +860,10 @@ class _ZebraMessageBody(type_desc.TypeDisp, stringify.StringifyMixin):
     def parse(cls, buf):
         return cls()
 
+    @classmethod
+    def parse_from_zebra(cls, buf):
+        return cls.parse(buf)
+
     def serialize(self):
         return b''
 
@@ -1155,8 +1175,14 @@ class _ZebraIPRoute(_ZebraMessageBody):
     """
     Base class for ZEBRA_IPV4_ROUTE_* and ZEBRA_IPV6_ROUTE_*
     message body.
+
+    .. Note::
+
+        Zebra IPv4/IPv6 Route message have asymmetric structure.
+        If the message sent from Zebra Daemon, set 'from_zebra=True' to
+        create an instance of this class.
     """
-    # Zebra IPv4/IPv6 Route message body:
+    # Zebra IPv4/IPv6 Route message body (Protocol Daemons -> Zebra Daemon):
     #  0                   1                   2                   3
     #  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -1178,33 +1204,93 @@ class _ZebraIPRoute(_ZebraMessageBody):
     # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     # | (TAG)                                                         |
     # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    _HEADER_FMT = '!BBBH'  # type, flags, message, safi
+    #
+    # Zebra IPv4/IPv6 Route message body (Zebra Daemon -> Protocol Daemons):
+    #  0                   1                   2                   3
+    #  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | Route Type    | Flags         | Message       |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | IPv4/v6 Prefix (Variable)                                     |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | (Nexthop Num) |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | (Nexthops (Variable))                                         |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | (IFIndex Num) |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | (Interface indexes)                                           |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | (Distance)    |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | (Metric)                                                      |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | (MTU)                                                         |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    # | (TAG)                                                         |
+    # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    _HEADER_FMT = '!BBB'  # type, flags, message
     HEADER_SIZE = struct.calcsize(_HEADER_FMT)
+    _SAFI_FMT = '!H'  # safi
+    SAFI_SIZE = struct.calcsize(_SAFI_FMT)
+    _NUM_FMT = '!B'  # nexthop_num or ifindex_num
+    NUM_SIZE = struct.calcsize(_NUM_FMT)
+    _IFINDEX_FMT = '!I'  # ifindex
+    IFINDEX_SIZE = struct.calcsize(_IFINDEX_FMT)
 
     # API type specific constants
     _FAMILY = None  # either socket.AF_INET or socket.AF_INET6
 
-    def __init__(self, route_type, flags, message, safi, prefix,
-                 nexthops=None,
+    def __init__(self, route_type, flags, message, safi=None, prefix=None,
+                 nexthops=None, ifindexes=None,
                  distance=None, metric=None, mtu=None, tag=None,
-                 _tail=None):
+                 from_zebra=False):
         super(_ZebraIPRoute, self).__init__()
         self.route_type = route_type
         self.flags = flags
         self.message = message
-        self.safi = safi
+
+        # SAFI should be included if this message sent to Zebra.
+        if from_zebra:
+            self.safi = None
+        else:
+            self.safi = safi or packet_safi.UNICAST
+
+        assert prefix is not None
         if isinstance(prefix, (IPv4Prefix, IPv6Prefix)):
             prefix = prefix.prefix
         self.prefix = prefix
+
+        # Nexthops should be a list of str representations of IP address
+        # if this message sent from Zebra, otherwise a list of _Nexthop
+        # subclasses.
         nexthops = nexthops or []
-        for nexthop in nexthops:
-            assert isinstance(nexthop, _NextHop)
+        if from_zebra:
+            for nexthop in nexthops:
+                assert (netaddr.valid_ipv4(nexthop)
+                        or netaddr.valid_ipv6(nexthop))
+        else:
+            for nexthop in nexthops:
+                assert isinstance(nexthop, _NextHop)
         self.nexthops = nexthops
+
+        # Interface indexes should be included if this message sent from
+        # Zebra.
+        if from_zebra:
+            ifindexes = ifindexes or []
+            for ifindex in ifindexes:
+                assert isinstance(ifindex, six.integer_types)
+            self.ifindexes = ifindexes
+        else:
+            self.ifindexes = None
+
         self.distance = distance
         self.metric = metric
         self.mtu = mtu
         self.tag = tag
-        self._tail = _tail or b''
+
+        # is this message sent from Zebra message or not.
+        self.from_zebra = from_zebra
 
     @classmethod
     def _parse_message_option(cls, message, flag, fmt, buf):
@@ -1215,14 +1301,44 @@ class _ZebraIPRoute(_ZebraMessageBody):
             return None, buf
 
     @classmethod
-    def parse(cls, buf):
-        (route_type, flags, message, safi) = struct.unpack_from(
+    def _parse_impl(cls, buf, from_zebra=False):
+        (route_type, flags, message,) = struct.unpack_from(
             cls._HEADER_FMT, buf)
         rest = buf[cls.HEADER_SIZE:]
 
+        if from_zebra:
+            safi = None
+        else:
+            (safi,) = struct.unpack_from(cls._SAFI_FMT, rest)
+            rest = rest[cls.SAFI_SIZE:]
+
         prefix, rest = _parse_ip_prefix(cls._FAMILY, rest)
 
-        nexthops, rest = _parse_nexthops(rest)
+        if from_zebra and message & ZAPI_MESSAGE_NEXTHOP:
+            nexthops = []
+            (nexthop_num,) = struct.unpack_from(cls._NUM_FMT, rest)
+            rest = rest[cls.NUM_SIZE:]
+            if cls._FAMILY == socket.AF_INET:
+                for _ in range(nexthop_num):
+                    nexthop = addrconv.ipv4.bin_to_text(rest[:4])
+                    nexthops.append(nexthop)
+                    rest = rest[4:]
+            else:  # cls._FAMILY == socket.AF_INET6:
+                for _ in range(nexthop_num):
+                    nexthop = addrconv.ipv6.bin_to_text(rest[:16])
+                    nexthops.append(nexthop)
+                    rest = rest[16:]
+        else:
+            nexthops, rest = _parse_nexthops(rest)
+
+        ifindexes = []
+        if from_zebra and message & ZAPI_MESSAGE_IFINDEX:
+            (ifindex_num,) = struct.unpack_from(cls._NUM_FMT, rest)
+            rest = rest[cls.NUM_SIZE:]
+            for _ in range(ifindex_num):
+                (ifindex,) = struct.unpack_from(cls._IFINDEX_FMT, rest)
+                ifindexes.append(ifindex)
+                rest = rest[cls.IFINDEX_SIZE:]
 
         distance, rest = cls._parse_message_option(
             message, ZAPI_MESSAGE_DISTANCE, '!B', rest)
@@ -1233,9 +1349,18 @@ class _ZebraIPRoute(_ZebraMessageBody):
         tag, rest = cls._parse_message_option(
             message, ZAPI_MESSAGE_TAG, '!I', rest)
 
-        return cls(route_type, flags, message, safi,
-                   prefix, nexthops,
-                   distance, metric, mtu, tag, _tail=rest)
+        return cls(route_type, flags, message, safi, prefix,
+                   nexthops, ifindexes,
+                   distance, metric, mtu, tag,
+                   from_zebra=from_zebra)
+
+    @classmethod
+    def parse(cls, buf):
+        return cls._parse_impl(buf)
+
+    @classmethod
+    def parse_from_zebra(cls, buf):
+        return cls._parse_impl(buf, from_zebra=True)
 
     def _serialize_message_option(self, option, flag, fmt):
         if option is None:
@@ -1249,9 +1374,22 @@ class _ZebraIPRoute(_ZebraMessageBody):
     def serialize(self):
         prefix = _serialize_ip_prefix(self.prefix)
 
-        nexthops = _serialize_nexthops(self.nexthops)
+        nexthops = b''
         if self.nexthops:
             self.message |= ZAPI_MESSAGE_NEXTHOP  # fixup
+            if self.from_zebra:
+                nexthops += struct.pack(self._NUM_FMT, len(self.nexthops))
+                for nexthop in self.nexthops:
+                    nexthops += ip.text_to_bin(nexthop)
+            else:
+                nexthops = _serialize_nexthops(self.nexthops)
+
+        ifindexes = b''
+        if self.ifindexes and self.from_zebra:
+            self.message |= ZAPI_MESSAGE_IFINDEX  # fixup
+            ifindexes += struct.pack(self._NUM_FMT, len(self.ifindexes))
+            for ifindex in self.ifindexes:
+                ifindexes += struct.pack(self._IFINDEX_FMT, ifindex)
 
         options = self._serialize_message_option(
             self.distance, ZAPI_MESSAGE_DISTANCE, '!B')
@@ -1263,10 +1401,11 @@ class _ZebraIPRoute(_ZebraMessageBody):
             self.tag, ZAPI_MESSAGE_TAG, '!I')
 
         header = struct.pack(
-            self._HEADER_FMT,
-            self.route_type, self.flags, self.message, self.safi)
+            self._HEADER_FMT, self.route_type, self.flags, self.message)
+        if not self.from_zebra:
+            header += struct.pack(self._SAFI_FMT, self.safi)
 
-        return header + prefix + nexthops + options + self._tail
+        return header + prefix + nexthops + ifindexes + options
 
 
 class _ZebraIPv4Route(_ZebraIPRoute):
diff --git a/ryu/services/protocols/zebra/client/zclient.py b/ryu/services/protocols/zebra/client/zclient.py
index 59d659d3..570a42c8 100644
--- a/ryu/services/protocols/zebra/client/zclient.py
+++ b/ryu/services/protocols/zebra/client/zclient.py
@@ -171,7 +171,7 @@ class ZServer(object):
                         recv_len = length - len(buf)
                         break
 
-                    msg, _, buf = zebra.ZebraMessage.parser(buf)
+                    msg, _, buf = zebra._ZebraMessageFromZebra.parser(buf)
 
                     ev = event.message_to_event(self.client, msg)
                     if ev: