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Add handover across areas
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@louisroyer
louisroyer committed Jan 30, 2025
1 parent 196fb2a commit cdd5d68
Showing 1 changed file with 248 additions and 45 deletions.
293 changes: 248 additions & 45 deletions internal/app/rules-pusher.go
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,12 @@ type RuleAction struct {
Action *n4tosrv6.Action
GtpDstPrefix netip.Prefix
}

type HandoverInfos struct {
UlTargetSrgw jsonapi.Fteid
DlTargetGnb *jsonapi.Fteid
}

type ueInfos struct {
sync.Mutex

Expand All @@ -49,8 +55,9 @@ type ueInfos struct {
Gnb string
Pushed bool

AnchorsRules []*RuleAction
AnchorsLock sync.RWMutex
HandoverInfos *HandoverInfos
AnchorsRules []*RuleAction
AnchorsLock sync.RWMutex

SRGWRules []*RuleAction
SRGWLock sync.RWMutex
Expand Down Expand Up @@ -127,6 +134,193 @@ func gnbInArea(gnb netip.Addr, area []netip.Prefix) bool {
return false
}

func (pusher *RulesPusher) pushHandoverAcrossAreas(ctx context.Context, ue_ip string) error {
i, ok := pusher.ues.Load(ue_ip)
if !ok {
return fmt.Errorf("UE not in ue list")
}
infos := i.(*ueInfos)
infos.Lock()
defer infos.Unlock()
if !infos.Pushed {
return nil // not pushed, nothing to do
}
if infos.HandoverInfos == nil {
return nil // no handover
}
if infos.HandoverInfos.DlTargetGnb == nil {
return nil // not enough info, yet
}
gnb_addr := infos.HandoverInfos.DlTargetGnb.Addr
ue_addr, err := netip.ParseAddr(ue_ip)
if err != nil {
return err
}
client := http.Client{}
logrus.WithFields(logrus.Fields{
"dl-teid": infos.HandoverInfos.DlTargetGnb.Teid,
"dl-addr": infos.HandoverInfos.DlTargetGnb.Addr,
"ul-teid": infos.HandoverInfos.UlTargetSrgw.Teid,
"ul-addr": infos.HandoverInfos.UlTargetSrgw.Addr,
"ue-ip": ue_ip,
}).Info("Pushing Handover Rules")
var wg sync.WaitGroup

for _, r := range pusher.uplink {
if r.Service == nil {
return fmt.Errorf("service configurated is nil for uplink rule")
}
//TODO: add ArgMobSession
srh, err := n4tosrv6.NewSRH(r.SegmentsList)
if err != nil {
logrus.WithFields(logrus.Fields{
"segments-list": r.SegmentsList,
}).WithError(err).Error("Creation of SRH uplink failed")
return err
}
var area []netip.Prefix
if r.Area != nil {
area = *r.Area
} else {
// if no area is defined, create a new-one with only this gnb
area = []netip.Prefix{netip.PrefixFrom(gnb_addr, 32)}
}
// check infos.Gnb in area
if !gnbInArea(gnb_addr, area) {
continue
}

action := n4tosrv6.Action{
SRH: *srh,
}
rule := n4tosrv6.Rule{
Enabled: r.Enabled,
Type: "uplink",
Match: n4tosrv6.Match{
Header: &n4tosrv6.GtpHeader{
OuterIpSrc: area,
FTeid: infos.HandoverInfos.UlTargetSrgw,
InnerIpSrc: &ue_addr,
},
Payload: &n4tosrv6.Payload{
// TODO: allow multiple services
Dst: *r.Service,
},
},
Action: action,
}
rule_json, err := json.Marshal(rule)
if err != nil {
logrus.WithError(err).Error("Could not marshal json")
return err
}
wg.Add(1)
// TODO: remove old rules
go func() error {
defer wg.Done()
//infos.SRGWLock.Lock()
//defer infos.SRGWLock.Unlock()
_, _ = pusher.pushSingleRule(ctx, client, r.ControlURI, rule_json)
// TODO: store this (after old rules are removed)
//if err == nil {
// infos.SRGWRules = append(infos.SRGWRules, &RuleAction{
// Url: url,
// Action: &action,
// })
//}
return err
}()

}

for _, r := range pusher.downlink {
var area []netip.Prefix
if r.Area != nil {
area = *r.Area
} else {
// if no area is defined, create a new-one with only this gnb
area = []netip.Prefix{netip.PrefixFrom(gnb_addr, 32)}
}
// check infos.Gnb in area
if !gnbInArea(gnb_addr, area) {
continue
}
if len(r.SegmentsList) == 0 {
logrus.Error("Empty segments list for downlink")
return fmt.Errorf("Empty segments list for downlink")
}
segList := make([]string, len(r.SegmentsList))
copy(segList, r.SegmentsList)
prefix, err := netip.ParsePrefix(r.SegmentsList[0])
if err != nil {
return err
}
dst := encoding.NewMGTP4IPv6Dst(prefix, gnb_addr.As4(), encoding.NewArgsMobSession(0, false, false, infos.HandoverInfos.DlTargetGnb.Teid))
dstB, err := dst.Marshal()
if err != nil {
return err
}
dstIp, ok := netip.AddrFromSlice(dstB)
if !ok {
return fmt.Errorf("could not convert MGTP4IPv6Dst to netip.Addr")
}
// note: in srv6, segment[n] is the first segment of the path, and segment[0] is the last segment in the path
// because Segment-Left is a pointer to the current segment and is decremented each SR-hop
segList[0] = dstIp.String()

srh, err := n4tosrv6.NewSRH(segList)
if err != nil {
logrus.WithFields(logrus.Fields{
"segments-list": r.SegmentsList,
}).WithError(err).Error("Creation of SRH downlink failed")
return err
}
action := n4tosrv6.Action{
SRH: *srh,
SourceGtp4: r.SrgwGtp4,
}
rule := n4tosrv6.Rule{
Enabled: true,
Type: "downlink",
Match: n4tosrv6.Match{
Payload: &n4tosrv6.Payload{
Dst: ue_addr,
},
},
Action: action,
}
rule_json, err := json.Marshal(rule)
if err != nil {
logrus.WithError(err).Error("Could not marshal json")
return err
}
wg.Add(1)
// TODO: remove old rules
go func() error {
defer wg.Done()
//infos.AnchorsLock.Lock()
//defer infos.AnchorsLock.Unlock()
_, _ = pusher.pushSingleRule(ctx, client, r.ControlURI, rule_json)
// TODO: store this (after old rules are removed)
//if err == nil {
// infos.AnchorsRules = append(infos.AnchorsRules, &RuleAction{
// Url: url,
// Action: &action,
// GtpDstPrefix: prefix,
// })
//}
return err
}()

}
wg.Wait()
infos.HandoverInfos = nil // reset handover state
pusher.ues.Store(ue_ip, infos)

return nil

}

func (pusher *RulesPusher) pushRTRRule(ctx context.Context, ue_ip string) error {
i, ok := pusher.ues.Load(ue_ip)
if !ok {
Expand Down Expand Up @@ -376,33 +570,6 @@ func (pusher *RulesPusher) pushHandover(ctx context.Context, ue_ip string, hando

func (pusher *RulesPusher) updateRoutersRules(ctx context.Context, msgType pfcputil.MessageType, msg pfcp_networking.ReceivedMessage, e *pfcp_networking.PFCPEntityUP) {
logrus.Debug("Into updateRoutersRules")
// detect handover with indirect forwarding

// 1. Establishment request:
// 1.1. new PDR UL (srgw1+teid)
// 1.2 FAR to edge
// -> we have UE ip and UL fteid, but we don't have gnb DL fteid yet
// => we don't know the area of the UE
// * store ul_fteids[ue_ip] = this ul fteid

// 2. Modification request:
// 2.1 PDR new fteid srgw1+teid (forw)
// 2.2 FAR gnbl3
// -> we don't have UE ip, we have a forw fteid

// 3. Modification request:
// 3.1 PDR new fteid srgw0+teid (forw)
// 3.2 FAR srgw1+teid
// -> we don't have UE ip, we have the forw fteid from step 2, we have the gnb fteid

// 4. Modification request:
// 4.1. PDR match UE
// 4.2. FAR to gnbl3
// -> we have the UE ip, we have the gnb DL fteid
// => we know the area of the UE
// * establish UL using fteid from step 1
// * establish DL using fteid from step 4

if msgType == message.MsgTypeSessionModificationRequest {
logrus.Debug("session modification request")
// check if handover
Expand Down Expand Up @@ -542,14 +709,31 @@ func (pusher *RulesPusher) updateRoutersRules(ctx context.Context, msgType pfcpu
AnchorsRules: make([]*RuleAction, 0),
SRGWRules: make([]*RuleAction, 0),
}); loaded {
logrus.WithFields(logrus.Fields{
"teid-uplink": fteid.TEID,
"ue-ipv4": ue_ipv4,
}).Debug("Updating UeInfos")
if ue.(*ueInfos).Pushed {
if addr == ue.(*ueInfos).UplinkFTeid.Addr && fteid.TEID == ue.(*ueInfos).UplinkFTeid.Teid {
return nil // old data
}
logrus.WithFields(logrus.Fields{
"teid-uplink": fteid.TEID,
"addr-uplink": addr,
"ue-ipv4": ue_ipv4,
}).Debug("Updating UeInfos with handoverInfos for uplink")
ue.(*ueInfos).Lock()
ue.(*ueInfos).HandoverInfos = &HandoverInfos{
UlTargetSrgw: jsonapi.Fteid{Teid: fteid.TEID, Addr: addr},
}
ue.(*ueInfos).Unlock()

ue.(*ueInfos).Lock()
ue.(*ueInfos).UplinkFTeid = jsonapi.Fteid{Teid: fteid.TEID, Addr: addr}
ue.(*ueInfos).Unlock()
} else {
logrus.WithFields(logrus.Fields{
"teid-uplink": fteid.TEID,
"ue-ipv4": ue_ipv4,
}).Debug("Updating UeInfos")

ue.(*ueInfos).Lock()
ue.(*ueInfos).UplinkFTeid = jsonapi.Fteid{Teid: fteid.TEID, Addr: addr}
ue.(*ueInfos).Unlock()
}
} else if logrus.IsLevelEnabled(logrus.DebugLevel) {
logrus.WithFields(logrus.Fields{
"teid-uplink": fteid.TEID,
Expand Down Expand Up @@ -578,15 +762,33 @@ func (pusher *RulesPusher) updateRoutersRules(ctx context.Context, msgType pfcpu
AnchorsRules: make([]*RuleAction, 0),
SRGWRules: make([]*RuleAction, 0),
}); loaded {
logrus.WithFields(logrus.Fields{
"gnb-ipv4": gnb_ipv4,
"teid-downlink": teid_downlink,
"ue-ipv4": ue_ipv4,
}).Debug("Updating UeInfos")
ue.(*ueInfos).Lock()
ue.(*ueInfos).Gnb = gnb_ipv4
ue.(*ueInfos).DownlinkTeid = teid_downlink
ue.(*ueInfos).Unlock()
if ue.(*ueInfos).Pushed {
if gnb_ipv4 == ue.(*ueInfos).Gnb && teid_downlink == ue.(*ueInfos).DownlinkTeid {
return nil // old info
}
addr, err := netip.ParseAddr(gnb_ipv4)
if err != nil {
return nil
}
logrus.WithFields(logrus.Fields{
"teid-downlink": teid_downlink,
"addr-downlink": gnb_ipv4,
"ue-ipv4": ue_ipv4,
}).Debug("Updating UeInfos with handoverInfos for downlink")
ue.(*ueInfos).Lock()
ue.(*ueInfos).HandoverInfos.DlTargetGnb = &jsonapi.Fteid{Teid: teid_downlink, Addr: addr}
ue.(*ueInfos).Unlock()
} else {
logrus.WithFields(logrus.Fields{
"gnb-ipv4": gnb_ipv4,
"teid-downlink": teid_downlink,
"ue-ipv4": ue_ipv4,
}).Debug("Updating UeInfos")
ue.(*ueInfos).Lock()
ue.(*ueInfos).Gnb = gnb_ipv4
ue.(*ueInfos).DownlinkTeid = teid_downlink
ue.(*ueInfos).Unlock()
}
} else if logrus.IsLevelEnabled(logrus.DebugLevel) {
logrus.WithFields(logrus.Fields{
"gnb-ipv4": gnb_ipv4,
Expand Down Expand Up @@ -628,6 +830,7 @@ func (pusher *RulesPusher) updateRoutersRules(ctx context.Context, msgType pfcpu
go func() {
defer wg.Done()
pusher.pushRTRRule(ctx, ip.(string))
pusher.pushHandoverAcrossAreas(ctx, ip.(string))
// TODO: check pushRTRRule return code and send pfcp error on failure
}()
return true
Expand Down

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