add packet library

As discussed on the mailing list, there is no good packet library
(parses and builds various protocol packets). dpkt isn't flexible
enough (can't nicely handle stacked protocols such as vlan, mpls,
gre). NOX's one is nice but released under GPL3.

So we need our own packet library.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

ryu/lib/packet/arp.py

@@ -0,0 +1,48 @@
+# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import struct
+from . import packet_base
+from ryu.ofproto.ofproto_parser import msg_pack_into
+
+
+class arp(packet_base.PacketBase):
+    _PACK_STR = '!HHBBH6sI6sI'
+
+    def __init__(self, hwtype, proto, hlen, plen, opcode,
+                 src_mac, src_ip, dst_mac, dst_ip):
+        super(arp, self).__init__()
+        self.hwtype = hwtype
+        self.proto = proto
+        self.hlen = hlen
+        self.plen = plen
+        self.opcode = opcode
+        self.src_mac = src_mac
+        self.src_ip = src_ip
+        self.dst_mac = dst_mac
+        self.dst_ip = dst_ip
+        self.length = struct.calcsize(arp._PACK_STR)
+
+    @classmethod
+    def parser(cls, buf):
+        (hwtype, proto, hlen, plen, opcode, src_mac, src_ip,
+         dst_mac, dst_ip) = struct.unpack_from(cls._PACK_STR, buf)
+        return cls(hwtype, proto, hlen, plen, opcode, src_mac, src_ip,
+                   dst_mac, dst_ip), None
+
+    def serialize(self, buf, offset):
+        msg_pack_into(arp._PACK_STR, buf, offset, self.hwtype, self.proto,
+                      self.hlen, self.plen, self.opcode,
+                      self.src_mac, self.src_ip, self.dst_mac, self.dst_ip)

ryu/lib/packet/ethernet.py

@@ -0,0 +1,45 @@
+# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import struct
+from . import packet_base
+from . import vlan
+from ryu.ofproto import ether
+from ryu.ofproto.ofproto_parser import msg_pack_into
+
+
+class ethernet(packet_base.PacketBase):
+    _PACK_STR = '!6s6sH'
+
+    def __init__(self, dst, src, ethertype):
+        super(ethernet, self).__init__()
+        self.dst = dst
+        self.src = src
+        self.ethertype = ethertype
+        self.length = struct.calcsize(ethernet._PACK_STR)
+
+    @classmethod
+    def parser(cls, buf):
+        dst, src, ethertype = struct.unpack_from(cls._PACK_STR, buf)
+        return cls(dst, src, ethertype), ethernet.get_packet_type(ethertype)
+
+    def serialize(self, buf, offset):
+        msg_pack_into(ethernet._PACK_STR, buf, offset,
+                      self.dst, self.src, self.ethertype)
+
+
+# copy vlan _TYPES
+ethernet._TYPES = vlan.vlan._TYPES
+ethernet.register_packet_type(vlan.vlan, ether.ETH_TYPE_8021Q)

ryu/lib/packet/ipv4.py

@@ -0,0 +1,80 @@
+# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import struct
+from . import packet_base
+from . import udp
+from ryu.ofproto.ofproto_parser import msg_pack_into
+from ryu.ofproto import inet
+
+class ipv4(packet_base.PacketBase):
+    _PACK_STR = '!BBHHHBBHII'
+
+    def __init__(self, version, header_length, tos, total_length,
+                 identification, flags, offset, ttl, proto, csum,
+                 src, dst):
+        super(ipv4, self).__init__()
+        self.version = version
+        self.header_length = header_length
+        self.tos = tos
+        self.total_length = total_length
+        self.identification = identification
+        self.flags = flags
+        self.offset = offset
+        self.ttl = ttl
+        self.proto = proto
+        self.csum = csum
+        self.src = src
+        self.dst = dst
+        self.length = header_length * 4
+
+    @classmethod
+    def parser(cls, buf):
+        (version, tos, total_length, identification, flags, ttl, proto, csum,
+         src, dst) = struct.unpack_from(cls._PACK_STR, buf)
+        header_length = version & 0xf
+        version = version >> 4
+        offset = flags & ((1 << 15) - 1)
+        flags = flags >> 15
+        msg = cls(version, header_length, tos, total_length, identification,
+                  flags, offset, ttl, proto, csum, src, dst)
+
+        if msg.length > struct.calcsize(ipv4._PACK_STR):
+            self.extra = buf[struct.calcsize(ipv4._PACK_STR):msg.length]
+
+        return msg, ipv4.get_packet_type(proto)
+
+    @staticmethod
+    def carry_around_add(a, b):
+        c = a + b
+        return (c & 0xffff) + (c >> 16)
+
+    def checksum(self, data):
+        s = 0
+        for i in range(0, len(data), 2):
+            w = data[i] + (data[i+1] << 8)
+            s = self.carry_around_add(s, w)
+        return ~s & 0xffff
+
+    def serialize(self, buf, offset):
+        version = self.version << 4 | self.header_length
+        flags = self.flags << 15 | self.offset
+        msg_pack_into(ipv4._PACK_STR, buf, offset, version, self.tos,
+                      self.total_length, self.identification, flags,
+                      self.ttl, self.proto, 0, self.src, self.dst)
+        self.csum = self.checksum(buf[offset:offset+self.length])
+        msg_pack_into('H', buf, offset + 10, self.csum)
+
+ipv4.register_packet_type(udp.udp, inet.IPPROTO_UDP)

ryu/lib/packet/packet.py

@@ -0,0 +1,49 @@
+# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from . import ethernet
+
+
+class Packet(object):
+    def __init__(self, data=None):
+        super(Packet, self).__init__()
+        self.data = data
+        self.protocols = []
+        self.parsed_bytes = 0
+        if self.data:
+            # Do we need to handle non ethernet?
+            self.parser(ethernet.ethernet)
+
+    def parser(self, cls):
+        while cls:
+            proto, cls = cls.parser(self.data[self.parsed_bytes:])
+            if proto:
+                self.parsed_bytes += proto.length
+                self.protocols.append(proto)
+
+    def serialize(self):
+        offset = 0
+        self.data = bytearray()
+        for p in self.protocols:
+            p.serialize(self.data, offset)
+            offset += p.length
+
+    def add_protocol(self, proto):
+        self.protocols.append(proto)
+
+    def find_protocol(self, name):
+        for p in self.protocols:
+            if p.__class__.__name__ == name:
+                return p

ryu/lib/packet/packet_base.py

@@ -0,0 +1,37 @@
+# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+class PacketBase(object):
+    _TYPES = {}
+
+    @classmethod
+    def get_packet_type(cls, type_):
+        return cls._TYPES.get(type_)
+
+    @classmethod
+    def register_packet_type(cls, cls_, type_):
+        cls._TYPES[type_] = cls_
+
+    def __init__(self):
+        super(PacketBase, self).__init__()
+        self.length = 0
+
+    @classmethod
+    def parser(cls):
+        pass
+
+    def serialize(self):
+        pass

ryu/lib/packet/udp.py

@@ -0,0 +1,44 @@
+# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import struct
+from . import packet_base
+from ryu.ofproto.ofproto_parser import msg_pack_into
+
+
+class udp(packet_base.PacketBase):
+    _PACK_STR = '!HHHH'
+
+    def __init__(self, src_port, dst_port, length, csum=0, data=None):
+        super(udp, self).__init__()
+        self.src_port = src_port
+        self.dst_port = dst_port
+        self.length = length
+        self.csum = csum
+        self.data = data
+
+    @classmethod
+    def parser(cls, buf):
+        (src_port, dst_port, length, csum) = struct.unpack_from(cls._PACK_STR,
+                                                                buf)
+        msg = cls(src_port, dst_port, length, csum)
+        if length > struct.calcsize(cls._PACK_STR):
+            msg.data = buf[struct.calcsize(cls._PACK_STR):length]
+
+        return msg, None
+
+    def serialize(self, buf, offset):
+        msg_pack_into(udp._PACK_STR, buf, offset, self.src_port, self.dst_port,
+                      self.length, self.csum)

ryu/lib/packet/vlan.py

@@ -0,0 +1,48 @@
+# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import struct
+from . import packet_base
+from . import arp
+from . import ipv4
+from ryu.ofproto import ether
+from ryu.ofproto.ofproto_parser import msg_pack_into
+
+
+class vlan(packet_base.PacketBase):
+    _PACK_STR = "!HH"
+
+    def __init__(self, pcp, cfi, vid, ethertype):
+        super(vlan, self).__init__()
+        self.pcp = pcp
+        self.cfi = cfi
+        self.vid = vid
+        self.ethertype = ethertype
+        self.length = struct.calcsize(vlan._PACK_STR)
+
+    @classmethod
+    def parser(cls, buf):
+        tci, ethertype = struct.unpack_from(cls._PACK_STR, buf)
+        pcp = tci >> 15
+        cfi = (tci >> 12) & 1
+        vid = tci & ((1 << 12) - 1)
+        return cls(pcp, cfi, vid, ethertype), vlan.get_packet_type(ethertype)
+
+    def serialize(self, buf, offset):
+        tci = self.pcp << 15 | self.cfi << 12 | self.vid
+        msg_pack_into(vlan._PACK_STR, buf, offset, tci, self.ethertype)
+
+vlan.register_packet_type(arp.arp, ether.ETH_TYPE_ARP)
+vlan.register_packet_type(ipv4.ipv4, ether.ETH_TYPE_IP)