bmp: Support number of withdraw updates and prefixes

This patch enables to send BMP statistics reports for the following types;
- Stat Type = 11: (32-bit Counter) Number of updates subjected to
  treat-as-withdraw treatment.
- Stat Type = 12: (32-bit Counter) Number of prefixes subjected to
  treat-as-withdraw treatment.

Note: Currently, this implementation considers only updates or prefixes
received from neighbors, but not enough to follow the handling process
described in RFC7606.

Signed-off-by: IWASE Yusuke <iwase.yusuke0@gmail.com>

2 files changed, 26 insertions, 0 deletions

diff --git a/server/bmp.go b/server/bmp.go
index 16db2c55..4d76822b 100644
--- a/server/bmp.go
+++ b/server/bmp.go
@@ -295,6 +295,8 @@ func bmpPeerStats(peerType uint8, peerDist uint64, timestamp int64, neighConf *c
 		[]bmp.BMPStatsTLVInterface{
 			bmp.NewBMPStatsTLV64(bmp.BMP_STAT_TYPE_ADJ_RIB_IN, uint64(neighConf.State.AdjTable.Accepted)),
 			bmp.NewBMPStatsTLV64(bmp.BMP_STAT_TYPE_LOC_RIB, uint64(neighConf.State.AdjTable.Advertised+neighConf.State.AdjTable.Filtered)),
+			bmp.NewBMPStatsTLV32(bmp.BMP_STAT_TYPE_WITHDRAW_UPDATE, neighConf.State.Messages.Received.WithdrawUpdate),
+			bmp.NewBMPStatsTLV32(bmp.BMP_STAT_TYPE_WITHDRAW_PREFIX, neighConf.State.Messages.Received.WithdrawPrefix),
 		},
 	)
 }
diff --git a/server/fsm.go b/server/fsm.go
index 6107f749..3817bd23 100644
--- a/server/fsm.go
+++ b/server/fsm.go
@@ -20,6 +20,7 @@ import (
 	"github.com/eapache/channels"
 	"github.com/osrg/gobgp/config"
 	"github.com/osrg/gobgp/packet/bgp"
+	"github.com/osrg/gobgp/packet/bmp"
 	"github.com/osrg/gobgp/table"
 	log "github.com/sirupsen/logrus"
 	"gopkg.in/tomb.v2"
@@ -182,6 +183,18 @@ func (fsm *FSM) bgpMessageStateUpdate(MessageType uint8, isIn bool) {
 	}
 }
 
+func (fsm *FSM) bmpStatsUpdate(statType uint16, increment int) {
+	stats := &fsm.pConf.State.Messages.Received
+	switch statType {
+	// TODO
+	// Support other stat types.
+	case bmp.BMP_STAT_TYPE_WITHDRAW_UPDATE:
+		stats.WithdrawUpdate += uint32(increment)
+	case bmp.BMP_STAT_TYPE_WITHDRAW_PREFIX:
+		stats.WithdrawPrefix += uint32(increment)
+	}
+}
+
 func NewFSM(gConf *config.Global, pConf *config.Neighbor, policy *table.RoutingPolicy) *FSM {
 	adminState := ADMIN_STATE_UP
 	if pConf.Config.AdminDown {
@@ -712,6 +725,17 @@ func (h *FSMHandler) recvMessageWithError() (*FsmMsg, error) {
 					return fmsg, err
 				}
 
+				if routes := len(body.WithdrawnRoutes); routes > 0 {
+					h.fsm.bmpStatsUpdate(bmp.BMP_STAT_TYPE_WITHDRAW_UPDATE, 1)
+					h.fsm.bmpStatsUpdate(bmp.BMP_STAT_TYPE_WITHDRAW_PREFIX, routes)
+				} else if attr := getPathAttrFromBGPUpdate(body, bgp.BGP_ATTR_TYPE_MP_UNREACH_NLRI); attr != nil {
+					mpUnreach := attr.(*bgp.PathAttributeMpUnreachNLRI)
+					if routes = len(mpUnreach.Value); routes > 0 {
+						h.fsm.bmpStatsUpdate(bmp.BMP_STAT_TYPE_WITHDRAW_UPDATE, 1)
+						h.fsm.bmpStatsUpdate(bmp.BMP_STAT_TYPE_WITHDRAW_PREFIX, routes)
+					}
+				}
+
 				table.UpdatePathAttrs4ByteAs(body)
 				if err = table.UpdatePathAggregator4ByteAs(body); err != nil {
 					fmsg.MsgData = err