From 6d0d613ca3cbfd543092c05dd0ba6c0809a309f7 Mon Sep 17 00:00:00 2001
From: Maximilian Wilhelm <max@sdn.clinic>
Date: Sat, 23 Jun 2018 23:30:29 +0200
Subject: [PATCH] Add tracking of contributing ASNs to a LocRIB.
The tracked contributing ASNs of a LocRIB will be used in detecting loops
within AS paths.
Signed-off-by: Maximilian Wilhelm <max@sdn.clinic>
---
protocols/bgp/server/fsm.go | 3 +-
protocols/bgp/server/fsm_established.go | 6 ++-
protocols/bgp/server/peer.go | 6 ++-
protocols/bgp/server/server.go | 7 +--
routingtable/adjRIBIn/adj_rib_in.go | 2 +-
routingtable/contributing_asn_list.go | 64 +++++++++++++++++++++++++
routingtable/locRIB/loc_rib.go | 13 +++--
7 files changed, 90 insertions(+), 11 deletions(-)
create mode 100644 routingtable/contributing_asn_list.go
diff --git a/protocols/bgp/server/fsm.go b/protocols/bgp/server/fsm.go
index 33e000d1..0c522139 100644
--- a/protocols/bgp/server/fsm.go
+++ b/protocols/bgp/server/fsm.go
@@ -8,6 +8,7 @@ import (
"github.com/bio-routing/bio-rd/protocols/bgp/packet"
"github.com/bio-routing/bio-rd/routingtable"
+ "github.com/bio-routing/bio-rd/routingtable/locRIB"
log "github.com/sirupsen/logrus"
)
@@ -61,7 +62,7 @@ type FSM struct {
ribsInitialized bool
adjRIBIn routingtable.RouteTableClient
adjRIBOut routingtable.RouteTableClient
- rib routingtable.RouteTableClient
+ rib *locRIB.LocRIB
updateSender routingtable.RouteTableClient
neighborID uint32
diff --git a/protocols/bgp/server/fsm_established.go b/protocols/bgp/server/fsm_established.go
index 80ff7fa7..58facab0 100644
--- a/protocols/bgp/server/fsm_established.go
+++ b/protocols/bgp/server/fsm_established.go
@@ -55,7 +55,10 @@ func (s establishedState) run() (state, string) {
}
func (s *establishedState) init() error {
- s.fsm.adjRIBIn = adjRIBIn.New(s.fsm.peer.importFilter)
+ contributingASNs := s.fsm.rib.GetContributingASNs()
+
+ s.fsm.adjRIBIn = adjRIBIn.New(s.fsm.peer.importFilter, contributingASNs)
+ contributingASNs.Add(s.fsm.peer.localASN)
s.fsm.adjRIBIn.Register(s.fsm.rib)
host, _, err := net.SplitHostPort(s.fsm.con.LocalAddr().String())
@@ -96,6 +99,7 @@ func (s *establishedState) init() error {
}
func (s *establishedState) uninit() {
+ s.fsm.rib.GetContributingASNs().Remove(s.fsm.peer.localASN)
s.fsm.adjRIBIn.Unregister(s.fsm.rib)
s.fsm.rib.Unregister(s.fsm.adjRIBOut)
s.fsm.adjRIBOut.Unregister(s.fsm.updateSender)
diff --git a/protocols/bgp/server/peer.go b/protocols/bgp/server/peer.go
index bad26828..3e5e6aee 100644
--- a/protocols/bgp/server/peer.go
+++ b/protocols/bgp/server/peer.go
@@ -5,6 +5,8 @@ import (
"sync"
"time"
+ "github.com/bio-routing/bio-rd/routingtable/locRIB"
+
"github.com/bio-routing/bio-rd/config"
"github.com/bio-routing/bio-rd/protocols/bgp/packet"
"github.com/bio-routing/bio-rd/routingtable"
@@ -27,7 +29,7 @@ type peer struct {
fsms []*FSM
fsmsMu sync.Mutex
- rib routingtable.RouteTableClient
+ rib *locRIB.LocRIB
routerID uint32
addPathSend routingtable.ClientOptions
addPathRecv bool
@@ -100,7 +102,7 @@ func isEstablishedState(s state) bool {
// NewPeer creates a new peer with the given config. If an connection is established, the adjRIBIN of the peer is connected
// to the given rib. To actually connect the peer, call Start() on the returned peer.
-func newPeer(c config.Peer, rib routingtable.RouteTableClient, server *bgpServer) (*peer, error) {
+func newPeer(c config.Peer, rib *locRIB.LocRIB, server *bgpServer) (*peer, error) {
if c.LocalAS == 0 {
c.LocalAS = server.localASN
}
diff --git a/protocols/bgp/server/server.go b/protocols/bgp/server/server.go
index 61c79de1..f0354f7e 100644
--- a/protocols/bgp/server/server.go
+++ b/protocols/bgp/server/server.go
@@ -7,9 +7,10 @@ import (
"strings"
"sync"
+ "github.com/bio-routing/bio-rd/routingtable/locRIB"
+
"github.com/bio-routing/bio-rd/config"
"github.com/bio-routing/bio-rd/protocols/bgp/packet"
- "github.com/bio-routing/bio-rd/routingtable"
log "github.com/sirupsen/logrus"
)
@@ -29,7 +30,7 @@ type bgpServer struct {
type BGPServer interface {
RouterID() uint32
Start(*config.Global) error
- AddPeer(config.Peer, routingtable.RouteTableClient) error
+ AddPeer(config.Peer, *locRIB.LocRIB) error
GetPeerInfoAll() map[string]PeerInfo
}
@@ -113,7 +114,7 @@ func (b *bgpServer) incomingConnectionWorker() {
}
}
-func (b *bgpServer) AddPeer(c config.Peer, rib routingtable.RouteTableClient) error {
+func (b *bgpServer) AddPeer(c config.Peer, rib *locRIB.LocRIB) error {
if c.LocalAS > uint16max || c.PeerAS > uint16max {
return fmt.Errorf("32bit ASNs are not supported yet")
}
diff --git a/routingtable/adjRIBIn/adj_rib_in.go b/routingtable/adjRIBIn/adj_rib_in.go
index ca9d0bb0..81416d9a 100644
--- a/routingtable/adjRIBIn/adj_rib_in.go
+++ b/routingtable/adjRIBIn/adj_rib_in.go
@@ -20,7 +20,7 @@ type AdjRIBIn struct {
}
// New creates a new Adjacency RIB In
-func New(exportFilter *filter.Filter) *AdjRIBIn {
+func New(exportFilter *filter.Filter, contributingASNs *routingtable.ContributingASNs) *AdjRIBIn {
a := &AdjRIBIn{
rt: routingtable.NewRoutingTable(),
exportFilter: exportFilter,
diff --git a/routingtable/contributing_asn_list.go b/routingtable/contributing_asn_list.go
new file mode 100644
index 00000000..0b0efca2
--- /dev/null
+++ b/routingtable/contributing_asn_list.go
@@ -0,0 +1,64 @@
+package routingtable
+
+import (
+ "sync"
+)
+
+type contributingASN struct {
+ asn uint32
+ count uint32
+}
+
+// ContributingASNs contains a list of contributing ASN to a LocRIB to check ASPaths for possible routing loops.
+type ContributingASNs struct {
+ contributingASNs []contributingASN
+ mu sync.RWMutex
+}
+
+// NewContributingASNs creates a list of contributing ASNs to a LocRIB for routing loop prevention.
+func NewContributingASNs() *ContributingASNs {
+ c := &ContributingASNs{
+ contributingASNs: []contributingASN{},
+ }
+
+ return c
+}
+
+// Add a new ASN to the list of contributing ASNs or add the ref count of an existing one.
+func (c *ContributingASNs) Add(asn uint32) {
+ c.mu.RLock()
+ defer c.mu.RUnlock()
+
+ for _, cASN := range c.contributingASNs {
+ if cASN.asn == asn {
+ cASN.count++
+ return
+ }
+ }
+
+ c.contributingASNs = append(c.contributingASNs, contributingASN{
+ asn: asn,
+ count: 1,
+ })
+}
+
+// Remove a ASN to the list of contributing ASNs or decrement the ref count of an existing one.
+func (c *ContributingASNs) Remove(asn uint32) {
+ c.mu.RLock()
+ defer c.mu.RUnlock()
+
+ asnList := c.contributingASNs
+
+ for i, cASN := range asnList {
+ if cASN.asn == asn {
+ cASN.count--
+
+ if cASN.count == 0 {
+ copy(asnList[i:], asnList[i+1:])
+ asnList = asnList[:len(asnList)]
+ c.contributingASNs = asnList[:len(asnList)-1]
+ }
+ return
+ }
+ }
+}
diff --git a/routingtable/locRIB/loc_rib.go b/routingtable/locRIB/loc_rib.go
index ff5750c3..a8ddf1e6 100644
--- a/routingtable/locRIB/loc_rib.go
+++ b/routingtable/locRIB/loc_rib.go
@@ -14,19 +14,26 @@ import (
// LocRIB represents a routing information base
type LocRIB struct {
routingtable.ClientManager
- rt *routingtable.RoutingTable
- mu sync.RWMutex
+ rt *routingtable.RoutingTable
+ mu sync.RWMutex
+ contributingASNs *routingtable.ContributingASNs
}
// New creates a new routing information base
func New() *LocRIB {
a := &LocRIB{
- rt: routingtable.NewRoutingTable(),
+ rt: routingtable.NewRoutingTable(),
+ contributingASNs: routingtable.NewContributingASNs(),
}
a.ClientManager = routingtable.NewClientManager(a)
return a
}
+// GetContributingASNs returns a pointer to the list of contributing ASNs
+func (a *LocRIB) GetContributingASNs() *routingtable.ContributingASNs {
+ return a.contributingASNs
+}
+
// UpdateNewClient sends current state to a new client
func (a *LocRIB) UpdateNewClient(client routingtable.RouteTableClient) error {
a.mu.RLock()
--
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