func tryConnect(service proxy.ServicePortName, srcAddr net.Addr, protocol string, proxier *Proxier) (out net.Conn, err error) {
for _, retryTimeout := range endpointDialTimeout {
endpoint, err := proxier.loadBalancer.NextEndpoint(service, srcAddr)
if err != nil {
glog.Errorf("Couldn't find an endpoint for %s: %v", service, err)
return nil, err
}
glog.V(3).Infof("Mapped service %q to endpoint %s", service, endpoint)
// TODO: This could spin up a new goroutine to make the outbound connection,
// and keep accepting inbound traffic.
outConn, err := net.DialTimeout(protocol, endpoint, retryTimeout*time.Second)
if err != nil {
if isTooManyFDsError(err) {
panic("Dial failed: " + err.Error())
}
glog.Errorf("Dial failed: %v", err)
continue
}
// Count transaction.
// TODO: For the first time, if dial timed out, should it be handled to indicate the service is not in the map.
proxier.TransactionCounter.Count(service.String(), endpoint)
return outConn, nil
}
return nil, fmt.Errorf("failed to connect to an endpoint.")
}
// Build a slice of iptables args that are common to from-container and from-host portal rules.
func iptablesCommonPortalArgs(destIP net.IP, addPhysicalInterfaceMatch bool, addDstLocalMatch bool, destPort int, protocol api.Protocol, service proxy.ServicePortName) []string {
// This list needs to include all fields as they are eventually spit out
// by iptables-save. This is because some systems do not support the
// 'iptables -C' arg, and so fall back on parsing iptables-save output.
// If this does not match, it will not pass the check. For example:
// adding the /32 on the destination IP arg is not strictly required,
// but causes this list to not match the final iptables-save output.
// This is fragile and I hope one day we can stop supporting such old
// iptables versions.
args := []string{
"-m", "comment",
"--comment", service.String(),
"-p", strings.ToLower(string(protocol)),
"-m", strings.ToLower(string(protocol)),
"--dport", fmt.Sprintf("%d", destPort),
}
if destIP != nil {
args = append(args, "-d", fmt.Sprintf("%s/32", destIP.String()))
}
if addPhysicalInterfaceMatch {
args = append(args, "-m", "physdev", "!", "--physdev-is-in")
}
if addDstLocalMatch {
args = append(args, "-m", "addrtype", "--dst-type", "LOCAL")
}
return args
}
// This is the same as servicePortChainName but with the endpoint included.
func servicePortEndpointChainName(s proxy.ServicePortName, protocol string, endpoint string) utiliptables.Chain {
hash := sha256.Sum256([]byte(s.String() + protocol + endpoint))
encoded := base32.StdEncoding.EncodeToString(hash[:])
return utiliptables.Chain("KUBE-SEP-" + encoded[:16])
}
// this is the same as servicePortToServiceChain but with the endpoint included essentially
func servicePortAndEndpointToServiceChain(s proxy.ServicePortName, endpoint string) utiliptables.Chain {
hash := sha256.Sum256([]byte(s.String() + "_" + endpoint))
encoded := base32.StdEncoding.EncodeToString(hash[:])
return utiliptables.Chain("KUBE-SEP-" + encoded[:19])
}
// servicePortToServiceChain takes the ServicePortName for a
// service and returns the associated iptables chain
// this is computed by hashing (sha256) then encoding to base64 and
// truncating with the prefix "KUBE-SVC-"
// We do this because Iptables Chain Names must be <= 28 chars long
func servicePortToServiceChain(s proxy.ServicePortName) utiliptables.Chain {
hash := sha256.Sum256([]byte(s.String()))
encoded := base32.StdEncoding.EncodeToString(hash[:])
return utiliptables.Chain("KUBE-SVC-" + encoded[:19])
}
// Build a slice of iptables args for an from-non-local public-port rule.
func (proxier *Proxier) iptablesNonLocalNodePortArgs(nodePort int, protocol api.Protocol, proxyIP net.IP, proxyPort int, service proxy.ServicePortName) []string {
args := iptablesCommonPortalArgs(nil, false, false, proxyPort, protocol, service)
args = append(args, "-m", "comment", "--comment", service.String(), "-m", "state", "--state", "NEW", "-j", "ACCEPT")
return args
}
// portProtoHash takes the ServicePortName and protocol for a service
// returns the associated 16 character hash. This is computed by hashing (sha256)
// then encoding to base32 and truncating to 16 chars. We do this because IPTables
// Chain Names must be <= 28 chars long, and the longer they are the harder they are to read.
func portProtoHash(s proxy.ServicePortName, protocol string) string {
hash := sha256.Sum256([]byte(s.String() + protocol))
encoded := base32.StdEncoding.EncodeToString(hash[:])
return encoded[:16]
}
