Merge 70578806 (automated)

8 files changed, 158 insertions, 20 deletions

diff --git a/pkg/sentry/socket/epsocket/epsocket.go b/pkg/sentry/socket/epsocket/epsocket.go
index f67451179..a50798cb3 100644
--- a/pkg/sentry/socket/epsocket/epsocket.go
+++ b/pkg/sentry/socket/epsocket/epsocket.go
@@ -920,6 +920,30 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa
 
 		t.Kernel().EmitUnimplementedEvent(t)
 
+	case linux.TCP_CONGESTION:
+		if outLen <= 0 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		var v tcpip.CongestionControlOption
+		if err := ep.GetSockOpt(&v); err != nil {
+			return nil, syserr.TranslateNetstackError(err)
+		}
+
+		// We match linux behaviour here where it returns the lower of
+		// TCP_CA_NAME_MAX bytes or the value of the option length.
+		//
+		// This is Linux's net/tcp.h TCP_CA_NAME_MAX.
+		const tcpCANameMax = 16
+
+		toCopy := tcpCANameMax
+		if outLen < tcpCANameMax {
+			toCopy = outLen
+		}
+		b := make([]byte, toCopy)
+		copy(b, v)
+		return b, nil
+
 	default:
 		emitUnimplementedEventTCP(t, name)
 	}
@@ -1222,6 +1246,12 @@ func setSockOptTCP(t *kernel.Task, ep commonEndpoint, name int, optVal []byte) *
 		}
 		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.KeepaliveIntervalOption(time.Second * time.Duration(v))))
 
+	case linux.TCP_CONGESTION:
+		v := tcpip.CongestionControlOption(optVal)
+		if err := ep.SetSockOpt(v); err != nil {
+			return syserr.TranslateNetstackError(err)
+		}
+		return nil
 	case linux.TCP_REPAIR_OPTIONS:
 		t.Kernel().EmitUnimplementedEvent(t)
 
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 85ef014d0..04c776205 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -472,6 +472,14 @@ type KeepaliveIntervalOption time.Duration
 // closed.
 type KeepaliveCountOption int
 
+// CongestionControlOption is used by SetSockOpt/GetSockOpt to set/get
+// the current congestion control algorithm.
+type CongestionControlOption string
+
+// AvailableCongestionControlOption is used to query the supported congestion
+// control algorithms.
+type AvailableCongestionControlOption string
+
 // MulticastTTLOption is used by SetSockOpt/GetSockOpt to control the default
 // TTL value for multicast messages. The default is 1.
 type MulticastTTLOption uint8
diff --git a/pkg/tcpip/transport/tcp/cubic.go b/pkg/tcpip/transport/tcp/cubic.go
index e618cd2b9..7b1f5e763 100644
--- a/pkg/tcpip/transport/tcp/cubic.go
+++ b/pkg/tcpip/transport/tcp/cubic.go
@@ -23,6 +23,7 @@ import (
 // control algorithm state.
 //
 // See: https://tools.ietf.org/html/rfc8312.
+// +stateify savable
 type cubicState struct {
 	// wLastMax is the previous wMax value.
 	wLastMax float64
@@ -33,7 +34,7 @@ type cubicState struct {
 
 	// t denotes the time when the current congestion avoidance
 	// was entered.
-	t time.Time
+	t time.Time `state:".(unixTime)"`
 
 	// numCongestionEvents tracks the number of congestion events since last
 	// RTO.
diff --git a/pkg/tcpip/transport/tcp/cubic_state.go b/pkg/tcpip/transport/tcp/cubic_state.go
new file mode 100644
index 000000000..d0f58cfaf
--- /dev/null
+++ b/pkg/tcpip/transport/tcp/cubic_state.go
@@ -0,0 +1,29 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tcp
+
+import (
+	"time"
+)
+
+// saveT is invoked by stateify.
+func (c *cubicState) saveT() unixTime {
+	return unixTime{c.t.Unix(), c.t.UnixNano()}
+}
+
+// loadT is invoked by stateify.
+func (c *cubicState) loadT(unix unixTime) {
+	c.t = time.Unix(unix.second, unix.nano)
+}
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 23422ca5e..1efe9d3fb 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -17,6 +17,7 @@ package tcp
 import (
 	"fmt"
 	"math"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -286,7 +287,7 @@ type endpoint struct {
 
 	// cc stores the name of the Congestion Control algorithm to use for
 	// this endpoint.
-	cc CongestionControlOption
+	cc tcpip.CongestionControlOption
 
 	// The following are used when a "packet too big" control packet is
 	// received. They are protected by sndBufMu. They are used to
@@ -394,7 +395,7 @@ func newEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, waite
 		e.rcvBufSize = rs.Default
 	}
 
-	var cs CongestionControlOption
+	var cs tcpip.CongestionControlOption
 	if err := stack.TransportProtocolOption(ProtocolNumber, &cs); err == nil {
 		e.cc = cs
 	}
@@ -898,6 +899,40 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		e.mu.Unlock()
 		return nil
 
+	case tcpip.CongestionControlOption:
+		// Query the available cc algorithms in the stack and
+		// validate that the specified algorithm is actually
+		// supported in the stack.
+		var avail tcpip.AvailableCongestionControlOption
+		if err := e.stack.TransportProtocolOption(ProtocolNumber, &avail); err != nil {
+			return err
+		}
+		availCC := strings.Split(string(avail), " ")
+		for _, cc := range availCC {
+			if v == tcpip.CongestionControlOption(cc) {
+				// Acquire the work mutex as we may need to
+				// reinitialize the congestion control state.
+				e.mu.Lock()
+				state := e.state
+				e.cc = v
+				e.mu.Unlock()
+				switch state {
+				case StateEstablished:
+					e.workMu.Lock()
+					e.mu.Lock()
+					if e.state == state {
+						e.snd.cc = e.snd.initCongestionControl(e.cc)
+					}
+					e.mu.Unlock()
+					e.workMu.Unlock()
+				}
+				return nil
+			}
+		}
+
+		// Linux returns ENOENT when an invalid congestion
+		// control algorithm is specified.
+		return tcpip.ErrNoSuchFile
 	default:
 		return nil
 	}
@@ -1067,6 +1102,12 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		}
 		return nil
 
+	case *tcpip.CongestionControlOption:
+		e.mu.Lock()
+		*o = e.cc
+		e.mu.Unlock()
+		return nil
+
 	default:
 		return tcpip.ErrUnknownProtocolOption
 	}
diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go
index b31bcccfa..59f4009a1 100644
--- a/pkg/tcpip/transport/tcp/protocol.go
+++ b/pkg/tcpip/transport/tcp/protocol.go
@@ -79,13 +79,6 @@ const (
 	ccCubic = "cubic"
 )
 
-// CongestionControlOption sets the current congestion control algorithm.
-type CongestionControlOption string
-
-// AvailableCongestionControlOption returns the supported congestion control
-// algorithms.
-type AvailableCongestionControlOption string
-
 type protocol struct {
 	mu                         sync.Mutex
 	sackEnabled                bool
@@ -93,7 +86,6 @@ type protocol struct {
 	recvBufferSize             ReceiveBufferSizeOption
 	congestionControl          string
 	availableCongestionControl []string
-	allowedCongestionControl   []string
 }
 
 // Number returns the tcp protocol number.
@@ -188,7 +180,7 @@ func (p *protocol) SetOption(option interface{}) *tcpip.Error {
 		p.mu.Unlock()
 		return nil
 
-	case CongestionControlOption:
+	case tcpip.CongestionControlOption:
 		for _, c := range p.availableCongestionControl {
 			if string(v) == c {
 				p.mu.Lock()
@@ -197,7 +189,9 @@ func (p *protocol) SetOption(option interface{}) *tcpip.Error {
 				return nil
 			}
 		}
-		return tcpip.ErrInvalidOptionValue
+		// linux returns ENOENT when an invalid congestion control
+		// is specified.
+		return tcpip.ErrNoSuchFile
 	default:
 		return tcpip.ErrUnknownProtocolOption
 	}
@@ -223,14 +217,14 @@ func (p *protocol) Option(option interface{}) *tcpip.Error {
 		*v = p.recvBufferSize
 		p.mu.Unlock()
 		return nil
-	case *CongestionControlOption:
+	case *tcpip.CongestionControlOption:
 		p.mu.Lock()
-		*v = CongestionControlOption(p.congestionControl)
+		*v = tcpip.CongestionControlOption(p.congestionControl)
 		p.mu.Unlock()
 		return nil
-	case *AvailableCongestionControlOption:
+	case *tcpip.AvailableCongestionControlOption:
 		p.mu.Lock()
-		*v = AvailableCongestionControlOption(strings.Join(p.availableCongestionControl, " "))
+		*v = tcpip.AvailableCongestionControlOption(strings.Join(p.availableCongestionControl, " "))
 		p.mu.Unlock()
 		return nil
 	default:
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index b236d7af2..daa3e8341 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -194,8 +194,6 @@ func newSender(ep *endpoint, iss, irs seqnum.Value, sndWnd seqnum.Size, mss uint
 
 	s := &sender{
 		ep:               ep,
-		sndCwnd:          InitialCwnd,
-		sndSsthresh:      math.MaxInt64,
 		sndWnd:           sndWnd,
 		sndUna:           iss + 1,
 		sndNxt:           iss + 1,
@@ -238,7 +236,13 @@ func newSender(ep *endpoint, iss, irs seqnum.Value, sndWnd seqnum.Size, mss uint
 	return s
 }
 
-func (s *sender) initCongestionControl(congestionControlName CongestionControlOption) congestionControl {
+// initCongestionControl initializes the specified congestion control module and
+// returns a handle to it. It also initializes the sndCwnd and sndSsThresh to
+// their initial values.
+func (s *sender) initCongestionControl(congestionControlName tcpip.CongestionControlOption) congestionControl {
+	s.sndCwnd = InitialCwnd
+	s.sndSsthresh = math.MaxInt64
+
 	switch congestionControlName {
 	case ccCubic:
 		return newCubicCC(s)
diff --git a/pkg/tcpip/transport/tcp/tcp_state_autogen.go b/pkg/tcpip/transport/tcp/tcp_state_autogen.go
index 5d7e11715..7d8c3009d 100755
--- a/pkg/tcpip/transport/tcp/tcp_state_autogen.go
+++ b/pkg/tcpip/transport/tcp/tcp_state_autogen.go
@@ -7,6 +7,36 @@ import (
 	"gvisor.googlesource.com/gvisor/pkg/tcpip/buffer"
 )
 
+func (x *cubicState) beforeSave() {}
+func (x *cubicState) save(m state.Map) {
+	x.beforeSave()
+	var t unixTime = x.saveT()
+	m.SaveValue("t", t)
+	m.Save("wLastMax", &x.wLastMax)
+	m.Save("wMax", &x.wMax)
+	m.Save("numCongestionEvents", &x.numCongestionEvents)
+	m.Save("c", &x.c)
+	m.Save("k", &x.k)
+	m.Save("beta", &x.beta)
+	m.Save("wC", &x.wC)
+	m.Save("wEst", &x.wEst)
+	m.Save("s", &x.s)
+}
+
+func (x *cubicState) afterLoad() {}
+func (x *cubicState) load(m state.Map) {
+	m.Load("wLastMax", &x.wLastMax)
+	m.Load("wMax", &x.wMax)
+	m.Load("numCongestionEvents", &x.numCongestionEvents)
+	m.Load("c", &x.c)
+	m.Load("k", &x.k)
+	m.Load("beta", &x.beta)
+	m.Load("wC", &x.wC)
+	m.Load("wEst", &x.wEst)
+	m.Load("s", &x.s)
+	m.LoadValue("t", new(unixTime), func(y interface{}) { x.loadT(y.(unixTime)) })
+}
+
 func (x *SACKInfo) beforeSave() {}
 func (x *SACKInfo) save(m state.Map) {
 	x.beforeSave()
@@ -383,6 +413,7 @@ func (x *segmentEntry) load(m state.Map) {
 }
 
 func init() {
+	state.Register("tcp.cubicState", (*cubicState)(nil), state.Fns{Save: (*cubicState).save, Load: (*cubicState).load})
 	state.Register("tcp.SACKInfo", (*SACKInfo)(nil), state.Fns{Save: (*SACKInfo).save, Load: (*SACKInfo).load})
 	state.Register("tcp.endpoint", (*endpoint)(nil), state.Fns{Save: (*endpoint).save, Load: (*endpoint).load})
 	state.Register("tcp.keepalive", (*keepalive)(nil), state.Fns{Save: (*keepalive).save, Load: (*keepalive).load})