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ofctrl_packetin.go
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/
ofctrl_packetin.go
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// Copyright 2021 Antrea Authors
//
// 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.
package openflow
import (
"encoding/binary"
"errors"
"fmt"
"antrea.io/libOpenflow/protocol"
"antrea.io/libOpenflow/util"
"antrea.io/ofnet/ofctrl"
)
const (
icmpEchoRequestType uint8 = 8
icmp6EchoRequestType uint8 = 128
// tcpStandardHdrLen is the TCP header length without options.
tcpStandardHdrLen uint8 = 5
)
func GetTCPHeaderData(ipPkt util.Message) (tcpSrcPort, tcpDstPort uint16, tcpSeqNum, tcpAckNum uint32, tcpHdrLen uint8, tcpFlags uint8, tcpWinSize uint16, err error) {
tcpIn, err := GetTCPPacketFromIPMessage(ipPkt)
if err != nil {
return 0, 0, 0, 0, 0, 0, 0, err
}
return tcpIn.PortSrc, tcpIn.PortDst, tcpIn.SeqNum, tcpIn.AckNum, tcpIn.HdrLen, tcpIn.Code, tcpIn.WinSize, nil
}
// GetTCPPacketFromIPMessage gets a TCP struct from an IP message.
func GetTCPPacketFromIPMessage(ipPkt util.Message) (tcpPkt *protocol.TCP, err error) {
var tcpBytes []byte
// Transfer Buffer to TCP
switch typedIPPkt := ipPkt.(type) {
case *protocol.IPv4:
tcpBytes, err = typedIPPkt.Data.(*util.Buffer).MarshalBinary()
case *protocol.IPv6:
tcpBytes, err = typedIPPkt.Data.(*util.Buffer).MarshalBinary()
}
if err != nil {
return nil, err
}
tcpPkt = new(protocol.TCP)
err = tcpPkt.UnmarshalBinary(tcpBytes)
if err != nil {
return nil, err
}
return tcpPkt, nil
}
func GetTCPDNSData(tcpPkt *protocol.TCP) (data []byte, length int, err error) {
// TCP.HdrLen is 4-octet unit indicating the length of TCP header including options.
tcpOptionsLen := (tcpPkt.HdrLen - tcpStandardHdrLen) * 4
// Move two more octet.
// From RFC 7766:
// DNS clients and servers SHOULD pass the two-octet length field, and
// the message described by that length field, to the TCP layer at the
// same time (e.g., in a single "write" system call) to make it more
// likely that all the data will be transmitted in a single TCP segment.
if int(tcpOptionsLen+2) > len(tcpPkt.Data) {
return nil, 0, fmt.Errorf("no DNS data in TCP data")
}
dnsDataLen := binary.BigEndian.Uint16(tcpPkt.Data[tcpOptionsLen : tcpOptionsLen+2])
dnsData := tcpPkt.Data[tcpOptionsLen+2:]
return dnsData, int(dnsDataLen), nil
}
func GetUDPHeaderData(ipPkt util.Message) (udpSrcPort, udpDstPort uint16, err error) {
var udpIn *protocol.UDP
switch typedIPPkt := ipPkt.(type) {
case *protocol.IPv4:
udpIn = typedIPPkt.Data.(*protocol.UDP)
case *protocol.IPv6:
udpIn = typedIPPkt.Data.(*protocol.UDP)
}
return udpIn.PortSrc, udpIn.PortDst, nil
}
func getICMPHeaderData(ipPkt util.Message) (icmpType, icmpCode uint8, icmpEchoID, icmpEchoSeq uint16, err error) {
switch typedIPPkt := ipPkt.(type) {
case *protocol.IPv4:
icmpIn := typedIPPkt.Data.(*protocol.ICMP)
if icmpIn.Type == icmpEchoRequestType {
if len(icmpIn.Data) < 4 {
return 0, 0, 0, 0, errors.New("ICMP payload is too short to unmarshal an ICMP echo message")
}
icmpEchoID = binary.BigEndian.Uint16(icmpIn.Data[:2])
icmpEchoSeq = binary.BigEndian.Uint16(icmpIn.Data[2:4])
}
icmpType = icmpIn.Type
icmpCode = icmpIn.Code
case *protocol.IPv6:
icmpIn := typedIPPkt.Data.(*protocol.ICMPv6EchoReqRpl)
if icmpIn.Type == icmp6EchoRequestType {
icmpEchoID = icmpIn.Identifier
icmpEchoSeq = icmpIn.SeqNum
}
icmpType = icmpIn.Type
icmpCode = icmpIn.Code
}
return icmpType, icmpCode, icmpEchoID, icmpEchoSeq, nil
}
func ParsePacketIn(pktIn *ofctrl.PacketIn) (*Packet, error) {
packet := Packet{}
ethernetData := new(protocol.Ethernet)
if err := ethernetData.UnmarshalBinary(pktIn.Data.(*util.Buffer).Bytes()); err != nil {
return nil, err
}
packet.DestinationMAC = ethernetData.HWDst
packet.SourceMAC = ethernetData.HWSrc
if ethernetData.Ethertype == protocol.IPv4_MSG {
ipPkt := ethernetData.Data.(*protocol.IPv4)
packet.DestinationIP = ipPkt.NWDst
packet.SourceIP = ipPkt.NWSrc
packet.TTL = ipPkt.TTL
packet.IPProto = ipPkt.Protocol
packet.IPFlags = ipPkt.Flags
packet.IPLength = ipPkt.Length
} else if ethernetData.Ethertype == protocol.IPv6_MSG {
ipPkt := ethernetData.Data.(*protocol.IPv6)
packet.DestinationIP = ipPkt.NWDst
packet.SourceIP = ipPkt.NWSrc
packet.TTL = ipPkt.HopLimit
packet.IPProto = ipPkt.NextHeader
// IPv6 header includes only playload length. Add 40 to count in
// the IPv6 header length.
packet.IPLength = ipPkt.Length + 40
packet.IsIPv6 = true
} else {
// Not an IP packet.
return &packet, nil
}
var err error
if packet.IPProto == protocol.Type_TCP {
packet.SourcePort, packet.DestinationPort, _, _, _, packet.TCPFlags, _, err = GetTCPHeaderData(ethernetData.Data)
} else if packet.IPProto == protocol.Type_UDP {
packet.SourcePort, packet.DestinationPort, err = GetUDPHeaderData(ethernetData.Data)
} else if packet.IPProto == protocol.Type_ICMP || packet.IPProto == protocol.Type_IPv6ICMP {
_, _, packet.ICMPEchoID, packet.ICMPEchoSeq, err = getICMPHeaderData(ethernetData.Data)
}
if err != nil {
return nil, err
}
return &packet, nil
}