| // Copyright 2016 The Netstack Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package udp |
| |
| import ( |
| "sync" |
| "sync/atomic" |
| |
| "github.com/google/netstack/tcpip" |
| "github.com/google/netstack/tcpip/buffer" |
| "github.com/google/netstack/tcpip/header" |
| "github.com/google/netstack/tcpip/stack" |
| "github.com/google/netstack/waiter" |
| ) |
| |
| type udpPacket struct { |
| udpPacketEntry |
| senderAddress tcpip.FullAddress |
| data buffer.VectorisedView |
| // views is used as buffer for data when its length is large |
| // enough to store a VectorisedView. |
| views [8]buffer.View |
| } |
| |
| type endpointState int |
| |
| const ( |
| stateInitial endpointState = iota |
| stateBound |
| stateConnected |
| stateClosed |
| ) |
| |
| // endpoint represents a UDP endpoint. This struct serves as the interface |
| // between users of the endpoint and the protocol implementation; it is legal to |
| // have concurrent goroutines make calls into the endpoint, they are properly |
| // synchronized. |
| type endpoint struct { |
| // The following fields are initialized at creation time and do not |
| // change throughout the lifetime of the endpoint. |
| stack *stack.Stack |
| netProto tcpip.NetworkProtocolNumber |
| waiterQueue *waiter.Queue |
| |
| // The following fields are used to manage the receive queue, and are |
| // protected by rcvMu. |
| rcvMu sync.Mutex |
| rcvReady bool |
| rcvList udpPacketList |
| rcvBufSizeMax int |
| rcvBufSize int |
| rcvClosed bool |
| |
| // The following fields are protected by the mu mutex. |
| mu sync.RWMutex |
| sndBufSize int |
| id stack.TransportEndpointID |
| state endpointState |
| bindNICID tcpip.NICID |
| bindAddr tcpip.Address |
| regNICID tcpip.NICID |
| route stack.Route |
| dstPort uint16 |
| v6only bool |
| multicastTTL uint8 |
| |
| // A list of multicast memberships that we need to remove when the endpoint |
| // is closed. Protected by the mu mutex. |
| multicastMemberships []multicastMembership |
| |
| // effectiveNetProtos contains the network protocols actually in use. In |
| // most cases it will only contain "netProto", but in cases like IPv6 |
| // endpoints with v6only set to false, this could include multiple |
| // protocols (e.g., IPv6 and IPv4) or a single different protocol (e.g., |
| // IPv4 when IPv6 endpoint is bound or connected to an IPv4 mapped |
| // address). |
| effectiveNetProtos []tcpip.NetworkProtocolNumber |
| } |
| |
| type multicastMembership struct { |
| nicID tcpip.NICID |
| multicastAddr tcpip.Address |
| } |
| |
| func newEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) *endpoint { |
| // TODO: Use the send buffer size initialized here. |
| return &endpoint{ |
| stack: stack, |
| netProto: netProto, |
| waiterQueue: waiterQueue, |
| v6only: true, |
| multicastTTL: 1, |
| rcvBufSizeMax: 32 * 1024, |
| sndBufSize: 32 * 1024, |
| } |
| } |
| |
| // NewConnectedEndpoint creates a new endpoint in the connected state using the |
| // provided route. |
| func NewConnectedEndpoint(stack *stack.Stack, r *stack.Route, id stack.TransportEndpointID, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) { |
| ep := newEndpoint(stack, r.NetProto, waiterQueue) |
| |
| // Register new endpoint so that packets are routed to it. |
| if err := stack.RegisterTransportEndpoint(r.NICID(), []tcpip.NetworkProtocolNumber{r.NetProto}, ProtocolNumber, id, ep); err != nil { |
| ep.Close() |
| return nil, err |
| } |
| |
| ep.id = id |
| ep.route = r.Clone() |
| ep.dstPort = id.RemotePort |
| ep.regNICID = r.NICID() |
| |
| ep.state = stateConnected |
| |
| return ep, nil |
| } |
| |
| func (e *endpoint) isPortReserved() bool { |
| return e.id.LocalPort != 0 |
| } |
| |
| // Close puts the endpoint in a closed state and frees all resources |
| // associated with it. |
| func (e *endpoint) Close() { |
| // Shutdown the endpoint so that we notify waiters that the endpoint is closed. |
| e.Shutdown(tcpip.ShutdownWrite | tcpip.ShutdownRead) |
| |
| e.mu.Lock() |
| defer e.mu.Unlock() |
| |
| switch e.state { |
| case stateBound, stateConnected: |
| e.stack.UnregisterTransportEndpoint(e.regNICID, e.effectiveNetProtos, ProtocolNumber, e.id) |
| e.stack.ReleasePort(e.effectiveNetProtos, ProtocolNumber, e.id.LocalAddress, e.id.LocalPort) |
| } |
| |
| for _, mem := range e.multicastMemberships { |
| e.stack.LeaveGroup(e.netProto, mem.nicID, mem.multicastAddr) |
| } |
| e.multicastMemberships = nil |
| |
| // Close the receive list and drain it. |
| e.rcvMu.Lock() |
| e.rcvClosed = true |
| e.rcvBufSize = 0 |
| for !e.rcvList.Empty() { |
| p := e.rcvList.Front() |
| e.rcvList.Remove(p) |
| } |
| e.rcvMu.Unlock() |
| |
| e.route.Release() |
| |
| // Update the state. |
| e.state = stateClosed |
| } |
| |
| // Read reads data from the endpoint. This method does not block if |
| // there is no data pending. |
| func (e *endpoint) Read(addr *tcpip.FullAddress) (buffer.View, *tcpip.Error) { |
| e.rcvMu.Lock() |
| |
| if e.rcvList.Empty() { |
| err := tcpip.ErrWouldBlock |
| if e.rcvClosed { |
| err = tcpip.ErrClosedForReceive |
| } |
| e.rcvMu.Unlock() |
| return buffer.View{}, err |
| } |
| |
| p := e.rcvList.Front() |
| e.rcvList.Remove(p) |
| e.rcvBufSize -= p.data.Size() |
| |
| e.rcvMu.Unlock() |
| |
| if addr != nil { |
| *addr = p.senderAddress |
| } |
| |
| return p.data.ToView(), nil |
| } |
| |
| // prepareForWrite prepares the endpoint for sending data. In particular, it |
| // binds it if it's still in the initial state. To do so, it must first |
| // reacquire the mutex in exclusive mode. |
| // |
| // Returns true for retry if preparation should be retried. |
| func (e *endpoint) prepareForWrite(to *tcpip.FullAddress) (retry bool, err *tcpip.Error) { |
| switch e.state { |
| case stateInitial: |
| case stateConnected: |
| return false, nil |
| |
| case stateBound: |
| if to == nil { |
| return false, tcpip.ErrDestinationRequired |
| } |
| return false, nil |
| default: |
| return false, tcpip.ErrInvalidEndpointState |
| } |
| |
| e.mu.RUnlock() |
| defer e.mu.RLock() |
| |
| e.mu.Lock() |
| defer e.mu.Unlock() |
| |
| // The state changed when we released the shared locked and re-acquired |
| // it in exclusive mode. Try again. |
| if e.state != stateInitial { |
| return true, nil |
| } |
| |
| // The state is still 'initial', so try to bind the endpoint. |
| if err := e.bindLocked(tcpip.FullAddress{}, nil); err != nil { |
| return false, err |
| } |
| |
| return true, nil |
| } |
| |
| // Write writes data to the endpoint's peer. This method does not block |
| // if the data cannot be written. |
| func (e *endpoint) Write(v buffer.View, to *tcpip.FullAddress) (uintptr, *tcpip.Error) { |
| e.mu.RLock() |
| defer e.mu.RUnlock() |
| |
| // Prepare for write. |
| for { |
| retry, err := e.prepareForWrite(to) |
| if err != nil { |
| return 0, err |
| } |
| |
| if !retry { |
| break |
| } |
| } |
| |
| route := &e.route |
| dstPort := e.dstPort |
| if to != nil { |
| // Reject destination address if it goes through a different |
| // NIC than the endpoint was bound to. |
| nicid := to.NIC |
| if e.bindNICID != 0 { |
| if nicid != 0 && nicid != e.bindNICID { |
| return 0, tcpip.ErrNoRoute |
| } |
| |
| nicid = e.bindNICID |
| } |
| |
| toCopy := *to |
| to = &toCopy |
| netProto, err := e.checkV4Mapped(to, true) |
| if err != nil { |
| return 0, err |
| } |
| |
| // Find the enpoint. |
| r, err := e.stack.FindRoute(nicid, e.bindAddr, to.Addr, netProto) |
| if err != nil { |
| return 0, err |
| } |
| defer r.Release() |
| |
| route = &r |
| dstPort = to.Port |
| } |
| |
| ttl := route.DefaultTTL() |
| if header.IsV4MulticastAddress(route.RemoteAddress) || header.IsV6MulticastAddress(route.RemoteAddress) { |
| ttl = e.multicastTTL |
| } |
| |
| err := sendUDP(route, v, e.id.LocalPort, dstPort, ttl) |
| if err != nil { |
| return 0, err |
| } |
| return uintptr(len(v)), nil |
| } |
| |
| // Peek only returns data from a single datagram, so do nothing here. |
| func (e *endpoint) Peek([][]byte) (uintptr, *tcpip.Error) { |
| return 0, nil |
| } |
| |
| // SetSockOpt sets a socket option. Currently not supported. |
| func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error { |
| // TODO: Actually implement this. |
| switch v := opt.(type) { |
| case tcpip.V6OnlyOption: |
| // We only recognize this option on v6 endpoints. |
| if e.netProto != header.IPv6ProtocolNumber { |
| return tcpip.ErrInvalidEndpointState |
| } |
| |
| e.mu.Lock() |
| defer e.mu.Unlock() |
| |
| // We only allow this to be set when we're in the initial state. |
| if e.state != stateInitial { |
| return tcpip.ErrInvalidEndpointState |
| } |
| |
| e.v6only = v != 0 |
| case tcpip.MulticastTTLOption: |
| e.mu.Lock() |
| defer e.mu.Unlock() |
| e.multicastTTL = uint8(v) |
| case tcpip.AddMembershipOption: |
| nicID := e.stack.CheckLocalAddress(0, v.InterfaceAddr) |
| if nicID == 0 { |
| return tcpip.ErrNoRoute |
| } |
| err := e.stack.JoinGroup(e.netProto, nicID, v.MulticastAddr) |
| if err != nil { |
| return err |
| } |
| |
| e.mu.Lock() |
| defer e.mu.Unlock() |
| |
| e.multicastMemberships = append(e.multicastMemberships, multicastMembership{nicID, v.MulticastAddr}) |
| case tcpip.RemoveMembershipOption: |
| nicID := e.stack.CheckLocalAddress(0, v.InterfaceAddr) |
| if nicID == 0 { |
| return tcpip.ErrNoRoute |
| } |
| err := e.stack.LeaveGroup(e.netProto, nicID, v.MulticastAddr) |
| if err != nil { |
| return err |
| } |
| |
| e.mu.Lock() |
| defer e.mu.Unlock() |
| for i, mem := range e.multicastMemberships { |
| if mem.nicID == nicID && mem.multicastAddr == v.MulticastAddr { |
| // Only remove the first match, so that each added membership above is |
| // paired with exactly 1 removal. |
| e.multicastMemberships[i] = e.multicastMemberships[len(e.multicastMemberships)-1] |
| e.multicastMemberships = e.multicastMemberships[:len(e.multicastMemberships)-1] |
| break |
| } |
| } |
| } |
| return nil |
| } |
| |
| // GetSockOpt implements tcpip.Endpoint.GetSockOpt. |
| func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error { |
| switch o := opt.(type) { |
| case tcpip.ErrorOption: |
| return nil |
| |
| case *tcpip.SendBufferSizeOption: |
| e.mu.Lock() |
| *o = tcpip.SendBufferSizeOption(e.sndBufSize) |
| e.mu.Unlock() |
| return nil |
| |
| case *tcpip.ReceiveBufferSizeOption: |
| e.rcvMu.Lock() |
| *o = tcpip.ReceiveBufferSizeOption(e.rcvBufSizeMax) |
| e.rcvMu.Unlock() |
| return nil |
| |
| case *tcpip.V6OnlyOption: |
| // We only recognize this option on v6 endpoints. |
| if e.netProto != header.IPv6ProtocolNumber { |
| return tcpip.ErrUnknownProtocolOption |
| } |
| |
| e.mu.Lock() |
| v := e.v6only |
| e.mu.Unlock() |
| |
| *o = 0 |
| if v { |
| *o = 1 |
| } |
| return nil |
| |
| case *tcpip.MulticastTTLOption: |
| e.mu.Lock() |
| *o = tcpip.MulticastTTLOption(e.multicastTTL) |
| e.mu.Unlock() |
| return nil |
| |
| case *tcpip.ReceiveQueueSizeOption: |
| e.rcvMu.Lock() |
| if e.rcvList.Empty() { |
| *o = 0 |
| } else { |
| p := e.rcvList.Front() |
| *o = tcpip.ReceiveQueueSizeOption(p.data.Size()) |
| } |
| e.rcvMu.Unlock() |
| return nil |
| } |
| |
| return tcpip.ErrUnknownProtocolOption |
| } |
| |
| // sendUDP sends a UDP segment via the provided network endpoint and under the |
| // provided identity. |
| func sendUDP(r *stack.Route, data buffer.View, localPort, remotePort uint16, ttl uint8) *tcpip.Error { |
| // Allocate a buffer for the UDP header. |
| hdr := buffer.NewPrependable(header.UDPMinimumSize + int(r.MaxHeaderLength())) |
| |
| // Initialize the header. |
| udp := header.UDP(hdr.Prepend(header.UDPMinimumSize)) |
| |
| length := uint16(hdr.UsedLength()) |
| xsum := r.PseudoHeaderChecksum(ProtocolNumber) |
| if data != nil { |
| length += uint16(len(data)) |
| xsum = header.Checksum(data, xsum) |
| } |
| |
| udp.Encode(&header.UDPFields{ |
| SrcPort: localPort, |
| DstPort: remotePort, |
| Length: length, |
| }) |
| |
| udp.SetChecksum(^udp.CalculateChecksum(xsum, length)) |
| |
| // Track count of packets sent. |
| atomic.AddUint64(&r.MutableStats().UDP.PacketsSent, 1) |
| |
| return r.WritePacket(&hdr, data, ProtocolNumber, ttl) |
| } |
| |
| func (e *endpoint) checkV4Mapped(addr *tcpip.FullAddress, allowMismatch bool) (tcpip.NetworkProtocolNumber, *tcpip.Error) { |
| netProto := e.netProto |
| if header.IsV4MappedAddress(addr.Addr) { |
| // Fail if using a v4 mapped address on a v6only endpoint. |
| if e.v6only { |
| return 0, tcpip.ErrNoRoute |
| } |
| |
| netProto = header.IPv4ProtocolNumber |
| addr.Addr = addr.Addr[header.IPv6AddressSize-header.IPv4AddressSize:] |
| if addr.Addr == "\x00\x00\x00\x00" { |
| addr.Addr = "" |
| } |
| } |
| |
| // Fail if we're bound to an address length different from the one we're |
| // checking. |
| if l := len(e.id.LocalAddress); !allowMismatch && l != 0 && l != len(addr.Addr) { |
| return 0, tcpip.ErrInvalidEndpointState |
| } |
| |
| return netProto, nil |
| } |
| |
| // Connect connects the endpoint to its peer. Specifying a NIC is optional. |
| func (e *endpoint) Connect(addr tcpip.FullAddress) *tcpip.Error { |
| if addr.Port == 0 { |
| // We don't support connecting to port zero. |
| return tcpip.ErrInvalidEndpointState |
| } |
| |
| e.mu.Lock() |
| defer e.mu.Unlock() |
| |
| nicid := addr.NIC |
| localPort := uint16(0) |
| switch e.state { |
| case stateInitial: |
| case stateBound, stateConnected: |
| localPort = e.id.LocalPort |
| if e.bindNICID == 0 { |
| break |
| } |
| |
| if nicid != 0 && nicid != e.bindNICID { |
| return tcpip.ErrInvalidEndpointState |
| } |
| |
| nicid = e.bindNICID |
| default: |
| return tcpip.ErrInvalidEndpointState |
| } |
| |
| netProto, err := e.checkV4Mapped(&addr, false) |
| if err != nil { |
| return err |
| } |
| |
| // Find a route to the desired destination. |
| r, err := e.stack.FindRoute(nicid, e.bindAddr, addr.Addr, netProto) |
| if err != nil { |
| return err |
| } |
| defer r.Release() |
| |
| id := stack.TransportEndpointID{ |
| LocalAddress: r.LocalAddress, |
| LocalPort: localPort, |
| RemotePort: addr.Port, |
| RemoteAddress: addr.Addr, |
| } |
| |
| // Even if we're connected, this endpoint can still be used to send |
| // packets on a different network protocol, so we register both even if |
| // v6only is set to false and this is an ipv6 endpoint. |
| netProtos := []tcpip.NetworkProtocolNumber{netProto} |
| if e.netProto == header.IPv6ProtocolNumber && !e.v6only { |
| netProtos = []tcpip.NetworkProtocolNumber{ |
| header.IPv4ProtocolNumber, |
| header.IPv6ProtocolNumber, |
| } |
| } |
| |
| id, err = e.registerWithStack(nicid, netProtos, id) |
| if err != nil { |
| return err |
| } |
| |
| // Remove the old registration. |
| if e.isPortReserved() { |
| e.stack.UnregisterTransportEndpoint(e.regNICID, e.effectiveNetProtos, ProtocolNumber, e.id) |
| } |
| |
| e.id = id |
| e.route = r.Clone() |
| e.dstPort = addr.Port |
| e.regNICID = nicid |
| e.effectiveNetProtos = netProtos |
| |
| e.state = stateConnected |
| |
| e.rcvMu.Lock() |
| e.rcvReady = true |
| e.rcvMu.Unlock() |
| |
| return nil |
| } |
| |
| // ConnectEndpoint is not supported. |
| func (*endpoint) ConnectEndpoint(tcpip.Endpoint) *tcpip.Error { |
| return tcpip.ErrInvalidEndpointState |
| } |
| |
| // Shutdown closes the read and/or write end of the endpoint connection |
| // to its peer. |
| func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error { |
| e.mu.RLock() |
| defer e.mu.RUnlock() |
| |
| // A socket in the bound state can still receive multicast messages, |
| // so we need to notify waiters on shutdown. |
| if e.state != stateBound && e.state != stateConnected { |
| return tcpip.ErrNotConnected |
| } |
| |
| if flags&tcpip.ShutdownRead != 0 { |
| e.rcvMu.Lock() |
| wasClosed := e.rcvClosed |
| e.rcvClosed = true |
| e.rcvMu.Unlock() |
| |
| if !wasClosed { |
| e.waiterQueue.Notify(waiter.EventIn) |
| } |
| } |
| |
| return nil |
| } |
| |
| // Listen is not supported by UDP, it just fails. |
| func (*endpoint) Listen(int) *tcpip.Error { |
| return tcpip.ErrNotSupported |
| } |
| |
| // Accept is not supported by UDP, it just fails. |
| func (*endpoint) Accept() (tcpip.Endpoint, *waiter.Queue, *tcpip.Error) { |
| return nil, nil, tcpip.ErrNotSupported |
| } |
| |
| func (e *endpoint) registerWithStack(nicid tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber, id stack.TransportEndpointID) (stack.TransportEndpointID, *tcpip.Error) { |
| // Reserve the port. |
| if !e.isPortReserved() { |
| port, err := e.stack.ReservePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort) |
| if err != nil { |
| return id, err |
| } |
| |
| id.LocalPort = port |
| } |
| |
| err := e.stack.RegisterTransportEndpoint(nicid, netProtos, ProtocolNumber, id, e) |
| if err != nil { |
| e.stack.ReleasePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort) |
| } |
| return id, err |
| } |
| |
| func (e *endpoint) bindLocked(addr tcpip.FullAddress, commit func() *tcpip.Error) *tcpip.Error { |
| // Don't allow binding once endpoint is not in the initial state |
| // anymore. |
| if e.state != stateInitial { |
| return tcpip.ErrInvalidEndpointState |
| } |
| |
| netProto, err := e.checkV4Mapped(&addr, false) |
| if err != nil { |
| return err |
| } |
| |
| // Expand netProtos to include v4 and v6 if the caller is binding to a |
| // wildcard (empty) address, and this is an IPv6 endpoint with v6only |
| // set to false. |
| netProtos := []tcpip.NetworkProtocolNumber{netProto} |
| if netProto == header.IPv6ProtocolNumber && !e.v6only && addr.Addr == "" { |
| netProtos = []tcpip.NetworkProtocolNumber{ |
| header.IPv6ProtocolNumber, |
| header.IPv4ProtocolNumber, |
| } |
| } |
| |
| if len(addr.Addr) != 0 { |
| // A local address was specified, verify that it's valid. |
| if e.stack.CheckLocalAddress(addr.NIC, addr.Addr) == 0 { |
| return tcpip.ErrBadLocalAddress |
| } |
| } |
| |
| id := stack.TransportEndpointID{ |
| LocalPort: addr.Port, |
| LocalAddress: addr.Addr, |
| } |
| |
| id, err = e.registerWithStack(addr.NIC, netProtos, id) |
| if err != nil { |
| return err |
| } |
| |
| if commit != nil { |
| if err := commit(); err != nil { |
| // Unregister, the commit failed. |
| e.stack.UnregisterTransportEndpoint(addr.NIC, netProtos, ProtocolNumber, id) |
| e.stack.ReleasePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort) |
| return err |
| } |
| } |
| |
| e.id = id |
| e.regNICID = addr.NIC |
| e.effectiveNetProtos = netProtos |
| |
| // Mark endpoint as bound. |
| e.state = stateBound |
| |
| e.rcvMu.Lock() |
| e.rcvReady = true |
| e.rcvMu.Unlock() |
| |
| return nil |
| } |
| |
| // Bind binds the endpoint to a specific local address and port. |
| // Specifying a NIC is optional. |
| func (e *endpoint) Bind(addr tcpip.FullAddress, commit func() *tcpip.Error) *tcpip.Error { |
| e.mu.Lock() |
| defer e.mu.Unlock() |
| |
| err := e.bindLocked(addr, commit) |
| if err != nil { |
| return err |
| } |
| |
| e.bindNICID = addr.NIC |
| e.bindAddr = addr.Addr |
| |
| return nil |
| } |
| |
| // GetLocalAddress returns the address to which the endpoint is bound. |
| func (e *endpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error) { |
| e.mu.RLock() |
| defer e.mu.RUnlock() |
| |
| return tcpip.FullAddress{ |
| NIC: e.regNICID, |
| Addr: e.id.LocalAddress, |
| Port: e.id.LocalPort, |
| }, nil |
| } |
| |
| // GetRemoteAddress returns the address to which the endpoint is connected. |
| func (e *endpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) { |
| e.mu.RLock() |
| defer e.mu.RUnlock() |
| |
| if e.state != stateConnected { |
| return tcpip.FullAddress{}, tcpip.ErrNotConnected |
| } |
| |
| return tcpip.FullAddress{ |
| NIC: e.regNICID, |
| Addr: e.id.RemoteAddress, |
| Port: e.id.RemotePort, |
| }, nil |
| } |
| |
| // Readiness returns the current readiness of the endpoint. For example, if |
| // waiter.EventIn is set, the endpoint is immediately readable. |
| func (e *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask { |
| // The endpoint is always writable. |
| result := waiter.EventOut & mask |
| |
| // Determine if the endpoint is readable if requested. |
| if (mask & waiter.EventIn) != 0 { |
| e.rcvMu.Lock() |
| if !e.rcvList.Empty() || e.rcvClosed { |
| result |= waiter.EventIn |
| } |
| e.rcvMu.Unlock() |
| } |
| |
| return result |
| } |
| |
| // HandlePacket is called by the stack when new packets arrive to this transport |
| // endpoint. |
| func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, vv *buffer.VectorisedView) { |
| // Get the header then trim it from the view. |
| hdr := header.UDP(vv.First()) |
| if int(hdr.Length()) > vv.Size() { |
| // Malformed packet. |
| atomic.AddUint64(&e.stack.MutableStats().UDP.MalformedPacketsReceived, 1) |
| return |
| } |
| |
| vv.TrimFront(header.UDPMinimumSize) |
| |
| e.rcvMu.Lock() |
| atomic.AddUint64(&e.stack.MutableStats().UDP.PacketsReceived, 1) |
| |
| // Drop the packet if our buffer is currently full. |
| if !e.rcvReady || e.rcvClosed || e.rcvBufSize >= e.rcvBufSizeMax { |
| atomic.AddUint64(&e.stack.MutableStats().UDP.ReceiveBufferErrors, 1) |
| e.rcvMu.Unlock() |
| return |
| } |
| |
| wasEmpty := e.rcvBufSize == 0 |
| |
| // Push new packet into receive list and increment the buffer size. |
| pkt := &udpPacket{ |
| senderAddress: tcpip.FullAddress{ |
| NIC: r.NICID(), |
| Addr: id.RemoteAddress, |
| Port: hdr.SourcePort(), |
| }, |
| } |
| pkt.data = vv.Clone(pkt.views[:]) |
| e.rcvList.PushBack(pkt) |
| e.rcvBufSize += vv.Size() |
| |
| e.rcvMu.Unlock() |
| |
| // Notify any waiters that there's data to be read now. |
| if wasEmpty { |
| e.waiterQueue.Notify(waiter.EventIn) |
| } |
| } |