diff options
Diffstat (limited to 'pkg/tcpip/tcpip.go')
| -rw-r--r-- | pkg/tcpip/tcpip.go | 270 |
1 files changed, 222 insertions, 48 deletions
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go index b7b227328..07c85ce59 100644 --- a/pkg/tcpip/tcpip.go +++ b/pkg/tcpip/tcpip.go @@ -43,6 +43,9 @@ import ( "gvisor.dev/gvisor/pkg/waiter" ) +// Using header.IPv4AddressSize would cause an import cycle. +const ipv4AddressSize = 4 + // Error represents an error in the netstack error space. Using a special type // ensures that errors outside of this space are not accidentally introduced. // @@ -192,7 +195,7 @@ func (e ErrSaveRejection) Error() string { return "save rejected due to unsupported networking state: " + e.Err.Error() } -// A Clock provides the current time. +// A Clock provides the current time and schedules work for execution. // // Times returned by a Clock should always be used for application-visible // time. Only monotonic times should be used for netstack internal timekeeping. @@ -203,6 +206,31 @@ type Clock interface { // NowMonotonic returns a monotonic time value. NowMonotonic() int64 + + // AfterFunc waits for the duration to elapse and then calls f in its own + // goroutine. It returns a Timer that can be used to cancel the call using + // its Stop method. + AfterFunc(d time.Duration, f func()) Timer +} + +// Timer represents a single event. A Timer must be created with +// Clock.AfterFunc. +type Timer interface { + // Stop prevents the Timer from firing. It returns true if the call stops the + // timer, false if the timer has already expired or been stopped. + // + // If Stop returns false, then the timer has already expired and the function + // f of Clock.AfterFunc(d, f) has been started in its own goroutine; Stop + // does not wait for f to complete before returning. If the caller needs to + // know whether f is completed, it must coordinate with f explicitly. + Stop() bool + + // Reset changes the timer to expire after duration d. + // + // Reset should be invoked only on stopped or expired timers. If the timer is + // known to have expired, Reset can be used directly. Otherwise, the caller + // must coordinate with the function f of Clock.AfterFunc(d, f). + Reset(d time.Duration) } // Address is a byte slice cast as a string that represents the address of a @@ -295,6 +323,29 @@ func (s *Subnet) Broadcast() Address { return Address(addr) } +// IsBroadcast returns true if the address is considered a broadcast address. +func (s *Subnet) IsBroadcast(address Address) bool { + // Only IPv4 supports the notion of a broadcast address. + if len(address) != ipv4AddressSize { + return false + } + + // Normally, we would just compare address with the subnet's broadcast + // address but there is an exception where a simple comparison is not + // correct. This exception is for /31 and /32 IPv4 subnets where all + // addresses are considered valid host addresses. + // + // For /31 subnets, the case is easy. RFC 3021 Section 2.1 states that + // both addresses in a /31 subnet "MUST be interpreted as host addresses." + // + // For /32, the case is a bit more vague. RFC 3021 makes no mention of /32 + // subnets. However, the same reasoning applies - if an exception is not + // made, then there do not exist any host addresses in a /32 subnet. RFC + // 4632 Section 3.1 also vaguely implies this interpretation by referring + // to addresses in /32 subnets as "host routes." + return s.Prefix() <= 30 && s.Broadcast() == address +} + // Equal returns true if s equals o. // // Needed to use cmp.Equal on Subnet as its fields are unexported. @@ -316,6 +367,28 @@ const ( ShutdownWrite ) +// PacketType is used to indicate the destination of the packet. +type PacketType uint8 + +const ( + // PacketHost indicates a packet addressed to the local host. + PacketHost PacketType = iota + + // PacketOtherHost indicates an outgoing packet addressed to + // another host caught by a NIC in promiscuous mode. + PacketOtherHost + + // PacketOutgoing for a packet originating from the local host + // that is looped back to a packet socket. + PacketOutgoing + + // PacketBroadcast indicates a link layer broadcast packet. + PacketBroadcast + + // PacketMulticast indicates a link layer multicast packet. + PacketMulticast +) + // FullAddress represents a full transport node address, as required by the // Connect() and Bind() methods. // @@ -549,6 +622,28 @@ type Endpoint interface { SetOwner(owner PacketOwner) } +// LinkPacketInfo holds Link layer information for a received packet. +// +// +stateify savable +type LinkPacketInfo struct { + // Protocol is the NetworkProtocolNumber for the packet. + Protocol NetworkProtocolNumber + + // PktType is used to indicate the destination of the packet. + PktType PacketType +} + +// PacketEndpoint are additional methods that are only implemented by Packet +// endpoints. +type PacketEndpoint interface { + // ReadPacket reads a datagram/packet from the endpoint and optionally + // returns the sender and additional LinkPacketInfo. + // + // This method does not block if there is no data pending. It will also + // either return an error or data, never both. + ReadPacket(*FullAddress, *LinkPacketInfo) (buffer.View, ControlMessages, *Error) +} + // EndpointInfo is the interface implemented by each endpoint info struct. type EndpointInfo interface { // IsEndpointInfo is an empty method to implement the tcpip.EndpointInfo @@ -585,85 +680,108 @@ type WriteOptions struct { type SockOptBool int const ( - // BroadcastOption is used by SetSockOpt/GetSockOpt to specify whether - // datagram sockets are allowed to send packets to a broadcast address. + // BroadcastOption is used by SetSockOptBool/GetSockOptBool to specify + // whether datagram sockets are allowed to send packets to a broadcast + // address. BroadcastOption SockOptBool = iota - // CorkOption is used by SetSockOpt/GetSockOpt to specify if data should be - // held until segments are full by the TCP transport protocol. + // CorkOption is used by SetSockOptBool/GetSockOptBool to specify if + // data should be held until segments are full by the TCP transport + // protocol. CorkOption - // DelayOption is used by SetSockOpt/GetSockOpt to specify if data - // should be sent out immediately by the transport protocol. For TCP, - // it determines if the Nagle algorithm is on or off. + // DelayOption is used by SetSockOptBool/GetSockOptBool to specify if + // data should be sent out immediately by the transport protocol. For + // TCP, it determines if the Nagle algorithm is on or off. DelayOption - // KeepaliveEnabledOption is used by SetSockOpt/GetSockOpt to specify whether - // TCP keepalive is enabled for this socket. + // KeepaliveEnabledOption is used by SetSockOptBool/GetSockOptBool to + // specify whether TCP keepalive is enabled for this socket. KeepaliveEnabledOption - // MulticastLoopOption is used by SetSockOpt/GetSockOpt to specify whether - // multicast packets sent over a non-loopback interface will be looped back. + // MulticastLoopOption is used by SetSockOptBool/GetSockOptBool to + // specify whether multicast packets sent over a non-loopback interface + // will be looped back. MulticastLoopOption - // PasscredOption is used by SetSockOpt/GetSockOpt to specify whether - // SCM_CREDENTIALS socket control messages are enabled. + // NoChecksumOption is used by SetSockOptBool/GetSockOptBool to specify + // whether UDP checksum is disabled for this socket. + NoChecksumOption + + // PasscredOption is used by SetSockOptBool/GetSockOptBool to specify + // whether SCM_CREDENTIALS socket control messages are enabled. // // Only supported on Unix sockets. PasscredOption - // QuickAckOption is stubbed out in SetSockOpt/GetSockOpt. + // QuickAckOption is stubbed out in SetSockOptBool/GetSockOptBool. QuickAckOption - // ReceiveTClassOption is used by SetSockOpt/GetSockOpt to specify if the - // IPV6_TCLASS ancillary message is passed with incoming packets. + // ReceiveTClassOption is used by SetSockOptBool/GetSockOptBool to + // specify if the IPV6_TCLASS ancillary message is passed with incoming + // packets. ReceiveTClassOption - // ReceiveTOSOption is used by SetSockOpt/GetSockOpt to specify if the TOS - // ancillary message is passed with incoming packets. + // ReceiveTOSOption is used by SetSockOptBool/GetSockOptBool to specify + // if the TOS ancillary message is passed with incoming packets. ReceiveTOSOption - // ReceiveIPPacketInfoOption is used by {G,S}etSockOptBool to specify - // if more inforamtion is provided with incoming packets such - // as interface index and address. + // ReceiveIPPacketInfoOption is used by SetSockOptBool/GetSockOptBool to + // specify if more inforamtion is provided with incoming packets such as + // interface index and address. ReceiveIPPacketInfoOption - // ReuseAddressOption is used by SetSockOpt/GetSockOpt to specify whether Bind() - // should allow reuse of local address. + // ReuseAddressOption is used by SetSockOptBool/GetSockOptBool to + // specify whether Bind() should allow reuse of local address. ReuseAddressOption - // ReusePortOption is used by SetSockOpt/GetSockOpt to permit multiple sockets - // to be bound to an identical socket address. + // ReusePortOption is used by SetSockOptBool/GetSockOptBool to permit + // multiple sockets to be bound to an identical socket address. ReusePortOption - // V6OnlyOption is used by {G,S}etSockOptBool to specify whether an IPv6 - // socket is to be restricted to sending and receiving IPv6 packets only. + // V6OnlyOption is used by SetSockOptBool/GetSockOptBool to specify + // whether an IPv6 socket is to be restricted to sending and receiving + // IPv6 packets only. V6OnlyOption + + // IPHdrIncludedOption is used by SetSockOpt to indicate for a raw + // endpoint that all packets being written have an IP header and the + // endpoint should not attach an IP header. + IPHdrIncludedOption ) // SockOptInt represents socket options which values have the int type. type SockOptInt int const ( - // KeepaliveCountOption is used by SetSockOpt/GetSockOpt to specify the number - // of un-ACKed TCP keepalives that will be sent before the connection is - // closed. + // KeepaliveCountOption is used by SetSockOptInt/GetSockOptInt to + // specify the number of un-ACKed TCP keepalives that will be sent + // before the connection is closed. KeepaliveCountOption SockOptInt = iota - // IPv4TOSOption is used by SetSockOpt/GetSockOpt to specify TOS + // IPv4TOSOption is used by SetSockOptInt/GetSockOptInt to specify TOS // for all subsequent outgoing IPv4 packets from the endpoint. IPv4TOSOption - // IPv6TrafficClassOption is used by SetSockOpt/GetSockOpt to specify TOS - // for all subsequent outgoing IPv6 packets from the endpoint. + // IPv6TrafficClassOption is used by SetSockOptInt/GetSockOptInt to + // specify TOS for all subsequent outgoing IPv6 packets from the + // endpoint. IPv6TrafficClassOption - // MaxSegOption is used by SetSockOpt/GetSockOpt to set/get the current - // Maximum Segment Size(MSS) value as specified using the TCP_MAXSEG option. + // MaxSegOption is used by SetSockOptInt/GetSockOptInt to set/get the + // current Maximum Segment Size(MSS) value as specified using the + // TCP_MAXSEG option. MaxSegOption - // MulticastTTLOption is used by SetSockOpt/GetSockOpt to control the default - // TTL value for multicast messages. The default is 1. + // MTUDiscoverOption is used to set/get the path MTU discovery setting. + // + // NOTE: Setting this option to any other value than PMTUDiscoveryDont + // is not supported and will fail as such, and getting this option will + // always return PMTUDiscoveryDont. + MTUDiscoverOption + + // MulticastTTLOption is used by SetSockOptInt/GetSockOptInt to control + // the default TTL value for multicast messages. The default is 1. MulticastTTLOption // ReceiveQueueSizeOption is used in GetSockOptInt to specify that the @@ -682,26 +800,45 @@ const ( // number of unread bytes in the output buffer should be returned. SendQueueSizeOption - // TTLOption is used by SetSockOpt/GetSockOpt to control the default TTL/hop - // limit value for unicast messages. The default is protocol specific. + // TTLOption is used by SetSockOptInt/GetSockOptInt to control the + // default TTL/hop limit value for unicast messages. The default is + // protocol specific. // // A zero value indicates the default. TTLOption - // TCPSynCountOption is used by SetSockOpt/GetSockOpt to specify the number of - // SYN retransmits that TCP should send before aborting the attempt to - // connect. It cannot exceed 255. + // TCPSynCountOption is used by SetSockOptInt/GetSockOptInt to specify + // the number of SYN retransmits that TCP should send before aborting + // the attempt to connect. It cannot exceed 255. // // NOTE: This option is currently only stubbed out and is no-op. TCPSynCountOption - // TCPWindowClampOption is used by SetSockOpt/GetSockOpt to bound the size - // of the advertised window to this value. + // TCPWindowClampOption is used by SetSockOptInt/GetSockOptInt to bound + // the size of the advertised window to this value. // // NOTE: This option is currently only stubed out and is a no-op TCPWindowClampOption ) +const ( + // PMTUDiscoveryWant is a setting of the MTUDiscoverOption to use + // per-route settings. + PMTUDiscoveryWant int = iota + + // PMTUDiscoveryDont is a setting of the MTUDiscoverOption to disable + // path MTU discovery. + PMTUDiscoveryDont + + // PMTUDiscoveryDo is a setting of the MTUDiscoverOption to always do + // path MTU discovery. + PMTUDiscoveryDo + + // PMTUDiscoveryProbe is a setting of the MTUDiscoverOption to set DF + // but ignore path MTU. + PMTUDiscoveryProbe +) + // ErrorOption is used in GetSockOpt to specify that the last error reported by // the endpoint should be cleared and returned. type ErrorOption struct{} @@ -740,7 +877,7 @@ type CongestionControlOption string // control algorithms. type AvailableCongestionControlOption string -// buffer moderation. +// ModerateReceiveBufferOption is used by buffer moderation. type ModerateReceiveBufferOption bool // TCPLingerTimeoutOption is used by SetSockOpt/GetSockOpt to set/get the @@ -813,7 +950,35 @@ type OutOfBandInlineOption int // a default TTL. type DefaultTTLOption uint8 -// IPPacketInfo is the message struture for IP_PKTINFO. +// SocketDetachFilterOption is used by SetSockOpt to detach a previously attached +// classic BPF filter on a given endpoint. +type SocketDetachFilterOption int + +// OriginalDestinationOption is used to get the original destination address +// and port of a redirected packet. +type OriginalDestinationOption FullAddress + +// TCPTimeWaitReuseOption is used stack.(*Stack).TransportProtocolOption to +// specify if the stack can reuse the port bound by an endpoint in TIME-WAIT for +// new connections when it is safe from protocol viewpoint. +type TCPTimeWaitReuseOption uint8 + +const ( + // TCPTimeWaitReuseDisabled indicates reuse of port bound by endponts in TIME-WAIT cannot + // be reused for new connections. + TCPTimeWaitReuseDisabled TCPTimeWaitReuseOption = iota + + // TCPTimeWaitReuseGlobal indicates reuse of port bound by endponts in TIME-WAIT can + // be reused for new connections irrespective of the src/dest addresses. + TCPTimeWaitReuseGlobal + + // TCPTimeWaitReuseLoopbackOnly indicates reuse of port bound by endpoint in TIME-WAIT can + // only be reused if the connection was a connection over loopback. i.e src/dest adddresses + // are loopback addresses. + TCPTimeWaitReuseLoopbackOnly +) + +// IPPacketInfo is the message structure for IP_PKTINFO. // // +stateify savable type IPPacketInfo struct { @@ -823,7 +988,7 @@ type IPPacketInfo struct { // LocalAddr is the local address. LocalAddr Address - // DestinationAddr is the destination address. + // DestinationAddr is the destination address found in the IP header. DestinationAddr Address } @@ -1198,6 +1363,12 @@ type UDPStats struct { // PacketSendErrors is the number of datagrams failed to be sent. PacketSendErrors *StatCounter + + // ChecksumErrors is the number of datagrams dropped due to bad checksums. + ChecksumErrors *StatCounter + + // InvalidSourceAddress is the number of invalid sourced datagrams dropped. + InvalidSourceAddress *StatCounter } // Stats holds statistics about the networking stack. @@ -1241,6 +1412,9 @@ type ReceiveErrors struct { // ClosedReceiver is the number of received packets dropped because // of receiving endpoint state being closed. ClosedReceiver StatCounter + + // ChecksumErrors is the number of packets dropped due to bad checksums. + ChecksumErrors StatCounter } // SendErrors collects packet send errors within the transport layer for |