first pass at restructuring service to one ip per hostname and impl reference counting. still some bugs in it though particularly around toggling identities on/off

service/cziti/dns.go

@@ -17,9 +17,9 @@
 
 package cziti
 
+import "C"
 import (
 	"encoding/binary"
-	"errors"
 	"fmt"
 	"net"
 	"sync"
@@ -47,67 +47,108 @@ type dnsImpl struct {
 	serviceMap map[string]ctxService
 
 	// dnsName -> ip address
-	hostnameMap map[string]net.IP
+	hostnameMap map[string]ctxIp
 	// ipv4 -> dnsName
-	ipMap map[uint32]string
+	//ipMap map[uint32]string
+}
+
+type ctxIp struct {
+	ctx     *CZitiCtx
+	ip      net.IP
+	network string
 }
 
 type ctxService struct {
-	ctx  *CZitiCtx
-	name string
+	ctx       *CZitiCtx
+	name      string
+	serviceId string
+	count     int
 }
 
 // RegisterService will return the next ip address in the configured range. If the ip address is not
 // assigned to a hostname an error will also be returned indicating why.
-func (dns *dnsImpl) RegisterService(dnsNameToReg string, port uint16, ctx *CZitiCtx, name string) (net.IP, error) {
+func (dns *dnsImpl) RegisterService(svcId string, dnsNameToReg string, port uint16, ctx *CZitiCtx, name string) (net.IP, error) {
 	log.Infof("adding DNS entry for service name %s@%s:%d", name, dnsNameToReg, port)
 	DnsInit(defaultCidr, defaultMaskBits)
 	dnsName := dnsNameToReg + "."
 	key := fmt.Sprint(dnsName, ':', port)
 
-	nextAddr := dns.cidr | atomic.AddUint32(&dns.counter, 1)
-	nextIp := make(net.IP, 4)
-	binary.BigEndian.PutUint32(nextIp, nextAddr)
+	var ip net.IP
 
-	if cs, found := dns.serviceMap[key]; found {
-		if cs.ctx != ctx || cs.name != name {
-			return nextIp, fmt.Errorf(
-				"service mapping conflict: %s:%d is already mapped for another context", dnsNameToReg, port)
+	currentNetwork := C.GoString(ctx.options.controller)
+
+	// check to see if the hostname is mapped...
+	if foundIp, found := dns.hostnameMap[dnsName]; found {
+		ip = foundIp.ip
+		// now check to see if the host *and* port are mapped...
+		if foundContext, found := dns.serviceMap[key]; found {
+			if foundIp.network != currentNetwork {
+				// means the host:port are mapped to some other *identity* already. that's an invalid state
+				return ip, fmt.Errorf("service mapping conflict: %s:%d in %s is already mapped for another identity in %s", dnsNameToReg, port, currentNetwork, foundIp.network)
+			}
+			if foundContext.serviceId != svcId {
+				// means the host:port are mapped to some other service already. that's an invalid state
+				return ip, fmt.Errorf("service mapping conflict: %s:%d is already mapped for another service", dnsNameToReg, port)
+			}
+			// while the host *AND* port are not used - the hostname is.
+			// need to increment the refcounter of how many service use this hostname
+			foundContext.count ++
+			log.Debugf("DNS mapping for %s used by another service. total services using %s = %d", dnsNameToReg, dnsNameToReg, foundContext.count)
+		} else {
+			// good - means the service can be mapped
+			dns.serviceMap[key] = ctxService{
+				ctx:  ctx,
+				name: name,
+				serviceId: svcId,
+				count: 1,
+			}
 		}
-		return nextIp, nil
 	} else {
+		// if not used at all - map it
+		nextAddr := dns.cidr | atomic.AddUint32(&dns.counter, 1)
+		ip = make(net.IP, 4)
+		binary.BigEndian.PutUint32(ip, nextAddr)
+
+		log.Infof("mapping hostname %s to ip %s", dnsNameToReg, ip.String())
+		dns.hostnameMap[dnsName] = ctxIp {
+			ip: ip,
+			ctx: ctx,
+			network: currentNetwork,
+		}
 		dns.serviceMap[key] = ctxService{
 			ctx:  ctx,
 			name: name,
+			serviceId: svcId,
+			count: 1,
 		}
-
-		if ip, mapped := dns.hostnameMap[dnsName]; mapped {
-			return ip, nil
-		}
-
-		dns.hostnameMap[dnsName] = nextIp
-		dns.ipMap[nextAddr] = dnsName
 	}
 
-	return nextIp, nil
+	return ip, nil
 }
 
 func (dns *dnsImpl) Resolve(dnsName string) net.IP {
-	return dns.hostnameMap[dnsName]
+	return dns.hostnameMap[dnsName].ip
 }
 
 func (dns *dnsImpl) DeregisterService(ctx *CZitiCtx, name string) {
 	for k, sc := range dns.serviceMap {
 		if sc.ctx == ctx && sc.name == name {
-			log.Infof("removing %s from DNS mapping", name)
-			delete(dns.serviceMap, k)
+			if sc.count < 1 {
+				log.Infof("removing %s from DNS mapping", name)
+				delete(dns.serviceMap, k)
+			} else {
+				// another service is using the mapping - can't remove it yet so decrement
+				sc.count --
+				log.Debugf("cannot remove dns mapping for %s yet - %d other services still use this hostname", name, sc.count)
+			}
 			return
 		}
 	}
 }
 
 func (this *dnsImpl) GetService(ip net.IP, port uint16) (*CZitiCtx, string, error) {
-	ipv4 := binary.BigEndian.Uint32(ip)
+	return nil, "", nil //not used yet
+	/*ipv4 := binary.BigEndian.Uint32(ip)
 	dns, found := this.ipMap[ipv4]
 	if !found {
 		return nil, "", errors.New("service not available")
@@ -119,13 +160,14 @@ func (this *dnsImpl) GetService(ip net.IP, port uint16) (*CZitiCtx, string, erro
 		return nil, "", errors.New("service not available")
 	}
 	return sc.ctx, sc.name, nil
+	*/
 }
 
 func DnsInit(ip string, maskBits int) {
 	initOnce.Do(func() {
 		DNS.serviceMap = make(map[string]ctxService)
-		DNS.ipMap = make(map[uint32]string)
-		DNS.hostnameMap = make(map[string]net.IP)
+		//DNS.ipMap = make(map[uint32]string)
+		DNS.hostnameMap = make(map[string]ctxIp)
 		i := net.ParseIP(ip).To4()
 		mask := net.CIDRMask(maskBits, 32)
 		DNS.cidr = binary.BigEndian.Uint32(i) & binary.BigEndian.Uint32(mask)

service/cziti/sdk.go

@@ -100,6 +100,7 @@ type Service struct {
 	InterceptHost string
 	InterceptPort uint16
 	AssignedIP    string
+	OwnsIntercept bool
 }
 
 type CZitiCtx struct {
@@ -135,7 +136,7 @@ func (c *CZitiCtx) Controller() string {
 var tunCfgName = C.CString("ziti-tunneler-client.v1")
 
 //export serviceCB
-func serviceCB(nf C.ziti_context, service *C.ziti_service, status C.int, data unsafe.Pointer) {
+func serviceCB(_ C.ziti_context, service *C.ziti_service, status C.int, data unsafe.Pointer) {
 	ctx := (*CZitiCtx)(data)
 
 	if ctx.Services == nil {
@@ -144,14 +145,14 @@ func serviceCB(nf C.ziti_context, service *C.ziti_service, status C.int, data un
 	}
 
 	name := C.GoString(service.name)
-	id := C.GoString(service.id)
-	log.Debugf("============ INSIDE serviceCB - status: %s:%s - %v, %v, %v ============", name, id, status, C.ZITI_SERVICE_UNAVAILABLE, C.ZITI_OK)
+	svcId := C.GoString(service.id)
+	log.Debugf("============ INSIDE serviceCB - status: %s:%s - %v, %v, %v ============", name, svcId, status, C.ZITI_SERVICE_UNAVAILABLE, C.ZITI_OK)
 	if status == C.ZITI_SERVICE_UNAVAILABLE {
-		found, ok := ctx.Services.Load(id)
+		found, ok := ctx.Services.Load(svcId)
 		fs := found.(Service)
 		if ok {
 			DNS.DeregisterService(ctx, name)
-			ctx.Services.Delete(id)
+			ctx.Services.Delete(svcId)
 			ServiceChanges <- ServiceChange{
 				Operation: REMOVED,
 				Service:   &fs,
@@ -174,23 +175,26 @@ func serviceCB(nf C.ziti_context, service *C.ziti_service, status C.int, data un
 			}
 		}
 		if host != "" && port != -1 {
-			ip, err := DNS.RegisterService(host, uint16(port), ctx, name)
+			ownsIntercept := true
+			ip, err := DNS.RegisterService(svcId, host, uint16(port), ctx, name)
 			if err != nil {
 				log.Warn(err)
+				ownsIntercept = false
 			} else {
 				log.Infof("service intercept beginning for service: %s@%s:%d on ip %s", name, host, port, ip.String())
 				for _, t := range devMap {
-					t.AddIntercept(id, name, ip.String(), port, unsafe.Pointer(ctx.zctx))
+					t.AddIntercept(svcId, name, ip.String(), port, unsafe.Pointer(ctx.zctx))
 				}
 			}
 			added := Service{
 				Name:          name,
-				Id:            id,
+				Id:            svcId,
 				InterceptHost: host,
 				InterceptPort: uint16(port),
 				AssignedIP:    ip.String(),
+				OwnsIntercept: ownsIntercept,
 			}
-			ctx.Services.Store(id, added)
+			ctx.Services.Store(svcId, added)
 			ServiceChanges <- ServiceChange{
 				Operation:   ADDED,
 				Service: &added,

service/ziti-tunnel/service/ipc.go

@@ -829,6 +829,7 @@ func acceptServices() {
 							InterceptPort: c.Service.InterceptPort,
 							Id:            c.Service.Id,
 							AssignedIP:    c.Service.AssignedIP,
+							OwnsIntercept: c.Service.OwnsIntercept,
 						}
 						id.Services = append(id.Services, &svc)