core/option/option.go
package option
import (
"fmt"
"golang.org/x/time/rate"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
"gvisor.dev/gvisor/pkg/tcpip/stack"
"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
)
const (
// defaultTimeToLive specifies the default TTL used by stack.
defaultTimeToLive uint8 = 64
// ipForwardingEnabled is the value used by stack to enable packet
// forwarding between NICs.
ipForwardingEnabled = true
// icmpBurst is the default number of ICMP messages that can be sent in
// a single burst.
icmpBurst = 50
// icmpLimit is the default maximum number of ICMP messages permitted
// by this rate limiter.
icmpLimit rate.Limit = 1000
// tcpCongestionControl is the congestion control algorithm used by
// stack. ccReno is the default option in gVisor stack.
tcpCongestionControlAlgorithm = "reno" // "reno" or "cubic"
// tcpDelayEnabled is the value used by stack to enable or disable
// tcp delay option. Disable Nagle's algorithm here by default.
tcpDelayEnabled = false
// tcpModerateReceiveBufferEnabled is the value used by stack to
// enable or disable tcp receive buffer auto-tuning option.
tcpModerateReceiveBufferEnabled = false
// tcpSACKEnabled is the value used by stack to enable or disable
// tcp selective ACK.
tcpSACKEnabled = true
// tcpRecovery is the loss detection algorithm used by TCP.
tcpRecovery = tcpip.TCPRACKLossDetection
// tcpMinBufferSize is the smallest size of a send/recv buffer.
tcpMinBufferSize = tcp.MinBufferSize
// tcpMaxBufferSize is the maximum permitted size of a send/recv buffer.
tcpMaxBufferSize = tcp.MaxBufferSize
// tcpDefaultBufferSize is the default size of the send buffer for
// a transport endpoint.
tcpDefaultSendBufferSize = tcp.DefaultSendBufferSize
// tcpDefaultReceiveBufferSize is the default size of the receive buffer
// for a transport endpoint.
tcpDefaultReceiveBufferSize = tcp.DefaultReceiveBufferSize
)
type Option func(*stack.Stack) error
// WithDefault sets all default values for stack.
func WithDefault() Option {
return func(s *stack.Stack) error {
opts := []Option{
WithDefaultTTL(defaultTimeToLive),
WithForwarding(ipForwardingEnabled),
// Config default stack ICMP settings.
WithICMPBurst(icmpBurst), WithICMPLimit(icmpLimit),
// We expect no packet loss, therefore we can bump buffers.
// Too large buffers thrash cache, so there is little point
// in too large buffers.
//
// Ref: https://github.com/cloudflare/slirpnetstack/blob/master/stack.go
WithTCPSendBufferSizeRange(tcpMinBufferSize, tcpDefaultSendBufferSize, tcpMaxBufferSize),
WithTCPReceiveBufferSizeRange(tcpMinBufferSize, tcpDefaultReceiveBufferSize, tcpMaxBufferSize),
WithTCPCongestionControl(tcpCongestionControlAlgorithm),
WithTCPDelay(tcpDelayEnabled),
// Receive Buffer Auto-Tuning Option, see:
// https://github.com/google/gvisor/issues/1666
WithTCPModerateReceiveBuffer(tcpModerateReceiveBufferEnabled),
// TCP selective ACK Option, see:
// https://tools.ietf.org/html/rfc2018
WithTCPSACKEnabled(tcpSACKEnabled),
// TCPRACKLossDetection: indicates RACK is used for loss detection and
// recovery.
//
// TCPRACKStaticReoWnd: indicates the reordering window should not be
// adjusted when DSACK is received.
//
// TCPRACKNoDupTh: indicates RACK should not consider the classic three
// duplicate acknowledgements rule to mark the segments as lost. This
// is used when reordering is not detected.
WithTCPRecovery(tcpRecovery),
}
for _, opt := range opts {
if err := opt(s); err != nil {
return err
}
}
return nil
}
}
// WithDefaultTTL sets the default TTL used by stack.
func WithDefaultTTL(ttl uint8) Option {
return func(s *stack.Stack) error {
opt := tcpip.DefaultTTLOption(ttl)
if err := s.SetNetworkProtocolOption(ipv4.ProtocolNumber, &opt); err != nil {
return fmt.Errorf("set ipv4 default TTL: %s", err)
}
if err := s.SetNetworkProtocolOption(ipv6.ProtocolNumber, &opt); err != nil {
return fmt.Errorf("set ipv6 default TTL: %s", err)
}
return nil
}
}
// WithForwarding sets packet forwarding between NICs for IPv4 & IPv6.
func WithForwarding(v bool) Option {
return func(s *stack.Stack) error {
if err := s.SetForwardingDefaultAndAllNICs(ipv4.ProtocolNumber, v); err != nil {
return fmt.Errorf("set ipv4 forwarding: %s", err)
}
if err := s.SetForwardingDefaultAndAllNICs(ipv6.ProtocolNumber, v); err != nil {
return fmt.Errorf("set ipv6 forwarding: %s", err)
}
return nil
}
}
// WithICMPBurst sets the number of ICMP messages that can be sent
// in a single burst.
func WithICMPBurst(burst int) Option {
return func(s *stack.Stack) error {
s.SetICMPBurst(burst)
return nil
}
}
// WithICMPLimit sets the maximum number of ICMP messages permitted
// by rate limiter.
func WithICMPLimit(limit rate.Limit) Option {
return func(s *stack.Stack) error {
s.SetICMPLimit(limit)
return nil
}
}
// WithTCPSendBufferSize sets default the send buffer size for TCP.
func WithTCPSendBufferSize(size int) Option {
return func(s *stack.Stack) error {
sndOpt := tcpip.TCPSendBufferSizeRangeOption{Min: tcpMinBufferSize, Default: size, Max: tcpMaxBufferSize}
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &sndOpt); err != nil {
return fmt.Errorf("set TCP send buffer size range: %s", err)
}
return nil
}
}
// WithTCPSendBufferSizeRange sets the send buffer size range for TCP.
func WithTCPSendBufferSizeRange(a, b, c int) Option {
return func(s *stack.Stack) error {
sndOpt := tcpip.TCPSendBufferSizeRangeOption{Min: a, Default: b, Max: c}
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &sndOpt); err != nil {
return fmt.Errorf("set TCP send buffer size range: %s", err)
}
return nil
}
}
// WithTCPReceiveBufferSize sets the default receive buffer size for TCP.
func WithTCPReceiveBufferSize(size int) Option {
return func(s *stack.Stack) error {
rcvOpt := tcpip.TCPReceiveBufferSizeRangeOption{Min: tcpMinBufferSize, Default: size, Max: tcpMaxBufferSize}
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &rcvOpt); err != nil {
return fmt.Errorf("set TCP receive buffer size range: %s", err)
}
return nil
}
}
// WithTCPReceiveBufferSizeRange sets the receive buffer size range for TCP.
func WithTCPReceiveBufferSizeRange(a, b, c int) Option {
return func(s *stack.Stack) error {
rcvOpt := tcpip.TCPReceiveBufferSizeRangeOption{Min: a, Default: b, Max: c}
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &rcvOpt); err != nil {
return fmt.Errorf("set TCP receive buffer size range: %s", err)
}
return nil
}
}
// WithTCPCongestionControl sets the current congestion control algorithm.
func WithTCPCongestionControl(cc string) Option {
return func(s *stack.Stack) error {
opt := tcpip.CongestionControlOption(cc)
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &opt); err != nil {
return fmt.Errorf("set TCP congestion control algorithm: %s", err)
}
return nil
}
}
// WithTCPDelay enables or disables Nagle's algorithm in TCP.
func WithTCPDelay(v bool) Option {
return func(s *stack.Stack) error {
opt := tcpip.TCPDelayEnabled(v)
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &opt); err != nil {
return fmt.Errorf("set TCP delay: %s", err)
}
return nil
}
}
// WithTCPModerateReceiveBuffer sets receive buffer moderation for TCP.
func WithTCPModerateReceiveBuffer(v bool) Option {
return func(s *stack.Stack) error {
opt := tcpip.TCPModerateReceiveBufferOption(v)
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &opt); err != nil {
return fmt.Errorf("set TCP moderate receive buffer: %s", err)
}
return nil
}
}
// WithTCPSACKEnabled sets the SACK option for TCP.
func WithTCPSACKEnabled(v bool) Option {
return func(s *stack.Stack) error {
opt := tcpip.TCPSACKEnabled(v)
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &opt); err != nil {
return fmt.Errorf("set TCP SACK: %s", err)
}
return nil
}
}
// WithTCPRecovery sets the recovery option for TCP.
func WithTCPRecovery(v tcpip.TCPRecovery) Option {
return func(s *stack.Stack) error {
if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &v); err != nil {
return fmt.Errorf("set TCP Recovery: %s", err)
}
return nil
}
}