From 433f77dc27792acc95ecc4ad3d5726aafc1b27ae Mon Sep 17 00:00:00 2001
From: Daniel Czerwonk <daniel@dan-nrw.de>
Date: Sat, 23 Jun 2018 19:16:56 +0200
Subject: [PATCH] added parsing for 4 byte ASN capability
---
protocols/bgp/packet/bgp.go | 4 +-
protocols/bgp/packet/decoder.go | 2 +-
protocols/bgp/packet/decoder_test.go | 6 +-
protocols/bgp/packet/encoder.go | 2 +-
protocols/bgp/packet/parameters.go | 8 ++
protocols/bgp/server/fsm2.go | 2 +-
protocols/bgp/server/fsm_open_sent.go | 24 +++++-
protocols/bgp/server/fsm_open_sent_test.go | 87 ++++++++++++++++++++++
8 files changed, 126 insertions(+), 9 deletions(-)
create mode 100644 protocols/bgp/server/fsm_open_sent_test.go
diff --git a/protocols/bgp/packet/bgp.go b/protocols/bgp/packet/bgp.go
index 622b46f3..8082f5dd 100644
--- a/protocols/bgp/packet/bgp.go
+++ b/protocols/bgp/packet/bgp.go
@@ -92,9 +92,11 @@ const (
UnicastSAFI = 1
CapabilitiesParamType = 2
AddPathCapabilityCode = 69
+ ASN4CapabilityCode = 65
AddPathReceive = 1
AddPathSend = 2
AddPathSendReceive = 3
+ ASTransASN = 23456
)
type BGPError struct {
@@ -119,7 +121,7 @@ type BGPHeader struct {
type BGPOpen struct {
Version uint8
- AS uint16
+ ASN uint16
HoldTime uint16
BGPIdentifier uint32
OptParmLen uint8
diff --git a/protocols/bgp/packet/decoder.go b/protocols/bgp/packet/decoder.go
index 31583bf1..e473f3ed 100644
--- a/protocols/bgp/packet/decoder.go
+++ b/protocols/bgp/packet/decoder.go
@@ -141,7 +141,7 @@ func _decodeOpenMsg(buf *bytes.Buffer) (interface{}, error) {
fields := []interface{}{
&msg.Version,
- &msg.AS,
+ &msg.ASN,
&msg.HoldTime,
&msg.BGPIdentifier,
&msg.OptParmLen,
diff --git a/protocols/bgp/packet/decoder_test.go b/protocols/bgp/packet/decoder_test.go
index a9ae237b..916660a3 100644
--- a/protocols/bgp/packet/decoder_test.go
+++ b/protocols/bgp/packet/decoder_test.go
@@ -156,7 +156,7 @@ func TestDecode(t *testing.T) {
},
Body: &BGPOpen{
Version: 4,
- AS: 200,
+ ASN: 200,
HoldTime: 15,
BGPIdentifier: uint32(169090600),
OptParmLen: 0,
@@ -184,7 +184,7 @@ func TestDecode(t *testing.T) {
},
Body: &BGPOpen{
Version: 4,
- AS: 200,
+ ASN: 200,
HoldTime: 15,
BGPIdentifier: uint32(100),
},
@@ -1512,7 +1512,7 @@ func TestDecodeOpenMsg(t *testing.T) {
wantFail: false,
expected: &BGPOpen{
Version: 4,
- AS: 257,
+ ASN: 257,
HoldTime: 15,
BGPIdentifier: 169090600,
OptParmLen: 0,
diff --git a/protocols/bgp/packet/encoder.go b/protocols/bgp/packet/encoder.go
index ea87d1ff..de2966bf 100644
--- a/protocols/bgp/packet/encoder.go
+++ b/protocols/bgp/packet/encoder.go
@@ -35,7 +35,7 @@ func SerializeOpenMsg(msg *BGPOpen) []byte {
serializeHeader(buf, openLen, OpenMsg)
buf.WriteByte(msg.Version)
- buf.Write(convert.Uint16Byte(msg.AS))
+ buf.Write(convert.Uint16Byte(msg.ASN))
buf.Write(convert.Uint16Byte(msg.HoldTime))
buf.Write(convert.Uint32Byte(msg.BGPIdentifier))
diff --git a/protocols/bgp/packet/parameters.go b/protocols/bgp/packet/parameters.go
index 8edf42fc..0ed9af66 100644
--- a/protocols/bgp/packet/parameters.go
+++ b/protocols/bgp/packet/parameters.go
@@ -52,3 +52,11 @@ func (a AddPathCapability) serialize(buf *bytes.Buffer) {
buf.WriteByte(a.SAFI)
buf.WriteByte(a.SendReceive)
}
+
+type ASN4Capability struct {
+ ASN4 uint32
+}
+
+func (a ASN4Capability) serialize(buf *bytes.Buffer) {
+ buf.Write(convert.Uint32Byte(a.ASN4))
+}
diff --git a/protocols/bgp/server/fsm2.go b/protocols/bgp/server/fsm2.go
index 6e1682c7..9b8163ab 100644
--- a/protocols/bgp/server/fsm2.go
+++ b/protocols/bgp/server/fsm2.go
@@ -221,7 +221,7 @@ func (fsm *FSM) resetConnectRetryCounter() {
func (fsm *FSM) sendOpen() error {
msg := packet.SerializeOpenMsg(&packet.BGPOpen{
Version: BGPVersion,
- AS: uint16(fsm.peer.localASN),
+ ASN: uint16(fsm.peer.localASN),
HoldTime: uint16(fsm.peer.holdTime / time.Second),
BGPIdentifier: fsm.peer.server.routerID,
OptParams: fsm.peer.optOpenParams,
diff --git a/protocols/bgp/server/fsm_open_sent.go b/protocols/bgp/server/fsm_open_sent.go
index 63680636..aba1193d 100644
--- a/protocols/bgp/server/fsm_open_sent.go
+++ b/protocols/bgp/server/fsm_open_sent.go
@@ -10,7 +10,8 @@ import (
)
type openSentState struct {
- fsm *FSM
+ fsm *FSM
+ peerASNRcvd uint32
}
func newOpenSentState(fsm *FSM) *openSentState {
@@ -104,6 +105,8 @@ func (s *openSentState) unexpectedMessage() (state, string) {
func (s *openSentState) openMsgReceived(msg *packet.BGPMessage) (state, string) {
openMsg := msg.Body.(*packet.BGPOpen)
+ s.peerASNRcvd = uint32(openMsg.ASN)
+
s.fsm.neighborID = openMsg.BGPIdentifier
stopTimer(s.fsm.connectRetryTimer)
if s.fsm.peer.collisionHandling(s.fsm) {
@@ -114,6 +117,10 @@ func (s *openSentState) openMsgReceived(msg *packet.BGPMessage) (state, string)
return s.tcpFailure()
}
+ return s.handleOpenMessage(openMsg)
+}
+
+func (s *openSentState) handleOpenMessage(openMsg *packet.BGPOpen) (state, string) {
s.fsm.holdTime = time.Duration(math.Min(float64(s.fsm.peer.holdTime), float64(time.Duration(openMsg.HoldTime)*time.Second)))
if s.fsm.holdTime != 0 {
if !s.fsm.holdTimer.Reset(s.fsm.holdTime) {
@@ -123,7 +130,13 @@ func (s *openSentState) openMsgReceived(msg *packet.BGPMessage) (state, string)
s.fsm.keepaliveTimer = time.NewTimer(s.fsm.keepaliveTime)
}
+ s.peerASNRcvd = uint32(openMsg.ASN)
s.processOpenOptions(openMsg.OptParams)
+
+ if s.peerASNRcvd != s.fsm.peer.peerASN {
+ return newCeaseState(), fmt.Sprintf("Expected session from %d, got open message with ASN %d", s.fsm.peer.peerASN, s.peerASNRcvd)
+ }
+
return newOpenConfirmState(s.fsm), "Received OPEN message"
}
@@ -153,7 +166,8 @@ func (s *openSentState) processCapability(cap packet.Capability) {
switch cap.Code {
case packet.AddPathCapabilityCode:
s.processAddPathCapability(cap.Value.(packet.AddPathCapability))
-
+ case packet.ASN4CapabilityCode:
+ s.processASN4Capability(cap.Value.(packet.ASN4Capability))
}
}
@@ -184,6 +198,12 @@ func (s *openSentState) processAddPathCapability(addPathCap packet.AddPathCapabi
}
}
+func (s *openSentState) processASN4Capability(cap packet.ASN4Capability) {
+ if s.peerASNRcvd == packet.ASTransASN {
+ s.peerASNRcvd = cap.ASN4
+ }
+}
+
func (s *openSentState) notification(msg *packet.BGPMessage) (state, string) {
stopTimer(s.fsm.connectRetryTimer)
s.fsm.con.Close()
diff --git a/protocols/bgp/server/fsm_open_sent_test.go b/protocols/bgp/server/fsm_open_sent_test.go
new file mode 100644
index 00000000..d4f2634e
--- /dev/null
+++ b/protocols/bgp/server/fsm_open_sent_test.go
@@ -0,0 +1,87 @@
+package server
+
+import (
+ "testing"
+
+ "github.com/bio-routing/bio-rd/protocols/bgp/packet"
+ "github.com/stretchr/testify/assert"
+)
+
+func TestOpenMsgReceived(t *testing.T) {
+ tests := []struct {
+ asn uint32
+ name string
+ msg packet.BGPOpen
+ wantsCease bool
+ }{
+ {
+ name: "valid open message (16bit ASN)",
+ asn: 12345,
+ msg: packet.BGPOpen{
+ HoldTime: 90,
+ BGPIdentifier: 1,
+ Version: 4,
+ ASN: 12345,
+ },
+ },
+ {
+ name: "valid open message (32bit ASN)",
+ asn: 202739,
+ msg: packet.BGPOpen{
+ HoldTime: 90,
+ BGPIdentifier: 1,
+ Version: 4,
+ ASN: 23456,
+ OptParmLen: 1,
+ OptParams: []packet.OptParam{
+ {
+ Type: packet.CapabilitiesParamType,
+ Length: 6,
+ Value: packet.Capabilities{
+ packet.Capability{
+ Code: packet.ASN4CapabilityCode,
+ Length: 4,
+ Value: packet.ASN4Capability{
+ ASN4: 202739,
+ },
+ },
+ },
+ },
+ },
+ },
+ },
+ {
+ name: "open message does not match configured remote ASN",
+ asn: 12345,
+ msg: packet.BGPOpen{
+ HoldTime: 90,
+ BGPIdentifier: 1,
+ Version: 4,
+ ASN: 54321,
+ },
+ wantsCease: true,
+ },
+ }
+
+ for _, test := range tests {
+ t.Run(test.name, func(t *testing.T) {
+ fsm := newFSM2(&Peer{
+ peerASN: test.asn,
+ })
+
+ s := &openSentState{
+ fsm: fsm,
+ }
+
+ state, _ := s.handleOpenMessage(&test.msg)
+
+ if test.wantsCease {
+ assert.IsType(t, &ceaseState{}, state, "state")
+ return
+ }
+
+ assert.IsType(t, &openConfirmState{}, state, "state")
+ assert.Equal(t, test.asn, s.peerASNRcvd, "asn")
+ })
+ }
+}
--
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