diff options
Diffstat (limited to 'pkg/tcpip/ports/ports.go')
| -rw-r--r-- | pkg/tcpip/ports/ports.go | 161 |
1 files changed, 123 insertions, 38 deletions
diff --git a/pkg/tcpip/ports/ports.go b/pkg/tcpip/ports/ports.go index 315780c0c..30cea8996 100644 --- a/pkg/tcpip/ports/ports.go +++ b/pkg/tcpip/ports/ports.go @@ -19,6 +19,7 @@ import ( "math" "math/rand" "sync" + "sync/atomic" "gvisor.dev/gvisor/pkg/tcpip" ) @@ -27,6 +28,10 @@ const ( // FirstEphemeral is the first ephemeral port. FirstEphemeral = 16000 + // numEphemeralPorts it the mnumber of available ephemeral ports to + // Netstack. + numEphemeralPorts = math.MaxUint16 - FirstEphemeral + 1 + anyIPAddress tcpip.Address = "" ) @@ -40,6 +45,13 @@ type portDescriptor struct { type PortManager struct { mu sync.RWMutex allocatedPorts map[portDescriptor]bindAddresses + + // hint is used to pick ports ephemeral ports in a stable order for + // a given port offset. + // + // hint must be accessed using the portHint/incPortHint helpers. + // TODO(gvisor.dev/issue/940): S/R this field. + hint uint32 } type portNode struct { @@ -47,43 +59,76 @@ type portNode struct { refs int } -// bindAddresses is a set of IP addresses. -type bindAddresses map[tcpip.Address]portNode +// deviceNode is never empty. When it has no elements, it is removed from the +// map that references it. +type deviceNode map[tcpip.NICID]portNode -// isAvailable checks whether an IP address is available to bind to. -func (b bindAddresses) isAvailable(addr tcpip.Address, reuse bool) bool { - if addr == anyIPAddress { - if len(b) == 0 { - return true - } +// isAvailable checks whether binding is possible by device. If not binding to a +// device, check against all portNodes. If binding to a specific device, check +// against the unspecified device and the provided device. +func (d deviceNode) isAvailable(reuse bool, bindToDevice tcpip.NICID) bool { + if bindToDevice == 0 { + // Trying to binding all devices. if !reuse { + // Can't bind because the (addr,port) is already bound. return false } - for _, n := range b { - if !n.reuse { + for _, p := range d { + if !p.reuse { + // Can't bind because the (addr,port) was previously bound without reuse. return false } } return true } - // If all addresses for this portDescriptor are already bound, no - // address is available. - if n, ok := b[anyIPAddress]; ok { - if !reuse { + if p, ok := d[0]; ok { + if !reuse || !p.reuse { return false } - if !n.reuse { + } + + if p, ok := d[bindToDevice]; ok { + if !reuse || !p.reuse { return false } } - if n, ok := b[addr]; ok { - if !reuse { + return true +} + +// bindAddresses is a set of IP addresses. +type bindAddresses map[tcpip.Address]deviceNode + +// isAvailable checks whether an IP address is available to bind to. If the +// address is the "any" address, check all other addresses. Otherwise, just +// check against the "any" address and the provided address. +func (b bindAddresses) isAvailable(addr tcpip.Address, reuse bool, bindToDevice tcpip.NICID) bool { + if addr == anyIPAddress { + // If binding to the "any" address then check that there are no conflicts + // with all addresses. + for _, d := range b { + if !d.isAvailable(reuse, bindToDevice) { + return false + } + } + return true + } + + // Check that there is no conflict with the "any" address. + if d, ok := b[anyIPAddress]; ok { + if !d.isAvailable(reuse, bindToDevice) { return false } - return n.reuse } + + // Check that this is no conflict with the provided address. + if d, ok := b[addr]; ok { + if !d.isAvailable(reuse, bindToDevice) { + return false + } + } + return true } @@ -97,11 +142,40 @@ func NewPortManager() *PortManager { // is suitable for its needs, and stopping when a port is found or an error // occurs. func (s *PortManager) PickEphemeralPort(testPort func(p uint16) (bool, *tcpip.Error)) (port uint16, err *tcpip.Error) { - count := uint16(math.MaxUint16 - FirstEphemeral + 1) - offset := uint16(rand.Int31n(int32(count))) + offset := uint32(rand.Int31n(numEphemeralPorts)) + return s.pickEphemeralPort(offset, numEphemeralPorts, testPort) +} + +// portHint atomically reads and returns the s.hint value. +func (s *PortManager) portHint() uint32 { + return atomic.LoadUint32(&s.hint) +} + +// incPortHint atomically increments s.hint by 1. +func (s *PortManager) incPortHint() { + atomic.AddUint32(&s.hint, 1) +} - for i := uint16(0); i < count; i++ { - port = FirstEphemeral + (offset+i)%count +// PickEphemeralPortStable starts at the specified offset + s.portHint and +// iterates over all ephemeral ports, allowing the caller to decide whether a +// given port is suitable for its needs and stopping when a port is found or an +// error occurs. +func (s *PortManager) PickEphemeralPortStable(offset uint32, testPort func(p uint16) (bool, *tcpip.Error)) (port uint16, err *tcpip.Error) { + p, err := s.pickEphemeralPort(s.portHint()+offset, numEphemeralPorts, testPort) + if err == nil { + s.incPortHint() + } + return p, err + +} + +// pickEphemeralPort starts at the offset specified from the FirstEphemeral port +// and iterates over the number of ports specified by count and allows the +// caller to decide whether a given port is suitable for its needs, and stopping +// when a port is found or an error occurs. +func (s *PortManager) pickEphemeralPort(offset, count uint32, testPort func(p uint16) (bool, *tcpip.Error)) (port uint16, err *tcpip.Error) { + for i := uint32(0); i < count; i++ { + port = uint16(FirstEphemeral + (offset+i)%count) ok, err := testPort(port) if err != nil { return 0, err @@ -116,17 +190,17 @@ func (s *PortManager) PickEphemeralPort(testPort func(p uint16) (bool, *tcpip.Er } // IsPortAvailable tests if the given port is available on all given protocols. -func (s *PortManager) IsPortAvailable(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, reuse bool) bool { +func (s *PortManager) IsPortAvailable(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, reuse bool, bindToDevice tcpip.NICID) bool { s.mu.Lock() defer s.mu.Unlock() - return s.isPortAvailableLocked(networks, transport, addr, port, reuse) + return s.isPortAvailableLocked(networks, transport, addr, port, reuse, bindToDevice) } -func (s *PortManager) isPortAvailableLocked(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, reuse bool) bool { +func (s *PortManager) isPortAvailableLocked(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, reuse bool, bindToDevice tcpip.NICID) bool { for _, network := range networks { desc := portDescriptor{network, transport, port} if addrs, ok := s.allocatedPorts[desc]; ok { - if !addrs.isAvailable(addr, reuse) { + if !addrs.isAvailable(addr, reuse, bindToDevice) { return false } } @@ -138,14 +212,14 @@ func (s *PortManager) isPortAvailableLocked(networks []tcpip.NetworkProtocolNumb // reserved by another endpoint. If port is zero, ReservePort will search for // an unreserved ephemeral port and reserve it, returning its value in the // "port" return value. -func (s *PortManager) ReservePort(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, reuse bool) (reservedPort uint16, err *tcpip.Error) { +func (s *PortManager) ReservePort(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, reuse bool, bindToDevice tcpip.NICID) (reservedPort uint16, err *tcpip.Error) { s.mu.Lock() defer s.mu.Unlock() // If a port is specified, just try to reserve it for all network // protocols. if port != 0 { - if !s.reserveSpecificPort(networks, transport, addr, port, reuse) { + if !s.reserveSpecificPort(networks, transport, addr, port, reuse, bindToDevice) { return 0, tcpip.ErrPortInUse } return port, nil @@ -153,13 +227,13 @@ func (s *PortManager) ReservePort(networks []tcpip.NetworkProtocolNumber, transp // A port wasn't specified, so try to find one. return s.PickEphemeralPort(func(p uint16) (bool, *tcpip.Error) { - return s.reserveSpecificPort(networks, transport, addr, p, reuse), nil + return s.reserveSpecificPort(networks, transport, addr, p, reuse, bindToDevice), nil }) } // reserveSpecificPort tries to reserve the given port on all given protocols. -func (s *PortManager) reserveSpecificPort(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, reuse bool) bool { - if !s.isPortAvailableLocked(networks, transport, addr, port, reuse) { +func (s *PortManager) reserveSpecificPort(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, reuse bool, bindToDevice tcpip.NICID) bool { + if !s.isPortAvailableLocked(networks, transport, addr, port, reuse, bindToDevice) { return false } @@ -171,11 +245,16 @@ func (s *PortManager) reserveSpecificPort(networks []tcpip.NetworkProtocolNumber m = make(bindAddresses) s.allocatedPorts[desc] = m } - if n, ok := m[addr]; ok { + d, ok := m[addr] + if !ok { + d = make(deviceNode) + m[addr] = d + } + if n, ok := d[bindToDevice]; ok { n.refs++ - m[addr] = n + d[bindToDevice] = n } else { - m[addr] = portNode{reuse: reuse, refs: 1} + d[bindToDevice] = portNode{reuse: reuse, refs: 1} } } @@ -184,22 +263,28 @@ func (s *PortManager) reserveSpecificPort(networks []tcpip.NetworkProtocolNumber // ReleasePort releases the reservation on a port/IP combination so that it can // be reserved by other endpoints. -func (s *PortManager) ReleasePort(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16) { +func (s *PortManager) ReleasePort(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber, addr tcpip.Address, port uint16, bindToDevice tcpip.NICID) { s.mu.Lock() defer s.mu.Unlock() for _, network := range networks { desc := portDescriptor{network, transport, port} if m, ok := s.allocatedPorts[desc]; ok { - n, ok := m[addr] + d, ok := m[addr] + if !ok { + continue + } + n, ok := d[bindToDevice] if !ok { continue } n.refs-- + d[bindToDevice] = n if n.refs == 0 { + delete(d, bindToDevice) + } + if len(d) == 0 { delete(m, addr) - } else { - m[addr] = n } if len(m) == 0 { delete(s.allocatedPorts, desc) |