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|
package p2p
import (
"math/rand"
"net"
"sync"
"time"
cfg "github.com/tendermint/go-config"
)
//--------------------------------------------------------
// delay reads/writes
// randomly drop reads/writes
// randomly drop connections
const (
FuzzModeDrop = "drop"
FuzzModeDelay = "delay"
)
func FuzzConn(config cfg.Config, conn net.Conn) net.Conn {
return &FuzzedConnection{
conn: conn,
start: time.After(time.Second * 10), // so we have time to do peer handshakes and get set up
params: config,
}
}
type FuzzedConnection struct {
conn net.Conn
mtx sync.Mutex
fuzz bool // we don't start fuzzing right away
start <-chan time.Time
// fuzz params
params cfg.Config
}
func (fc *FuzzedConnection) randomDuration() time.Duration {
return time.Millisecond * time.Duration(rand.Int()%fc.MaxDelayMilliseconds())
}
func (fc *FuzzedConnection) Active() bool {
return fc.params.GetBool(configFuzzActive)
}
func (fc *FuzzedConnection) Mode() string {
return fc.params.GetString(configFuzzMode)
}
func (fc *FuzzedConnection) ProbDropRW() float64 {
return fc.params.GetFloat64(configFuzzProbDropRW)
}
func (fc *FuzzedConnection) ProbDropConn() float64 {
return fc.params.GetFloat64(configFuzzProbDropConn)
}
func (fc *FuzzedConnection) ProbSleep() float64 {
return fc.params.GetFloat64(configFuzzProbSleep)
}
func (fc *FuzzedConnection) MaxDelayMilliseconds() int {
return fc.params.GetInt(configFuzzMaxDelayMilliseconds)
}
// implements the fuzz (delay, kill conn)
// and returns whether or not the read/write should be ignored
func (fc *FuzzedConnection) Fuzz() bool {
if !fc.shouldFuzz() {
return false
}
switch fc.Mode() {
case FuzzModeDrop:
// randomly drop the r/w, drop the conn, or sleep
r := rand.Float64()
if r <= fc.ProbDropRW() {
return true
} else if r < fc.ProbDropRW()+fc.ProbDropConn() {
// XXX: can't this fail because machine precision?
// XXX: do we need an error?
fc.Close()
return true
} else if r < fc.ProbDropRW()+fc.ProbDropConn()+fc.ProbSleep() {
time.Sleep(fc.randomDuration())
}
case FuzzModeDelay:
// sleep a bit
time.Sleep(fc.randomDuration())
}
return false
}
// we don't fuzz until start chan fires
func (fc *FuzzedConnection) shouldFuzz() bool {
if !fc.Active() {
return false
}
fc.mtx.Lock()
defer fc.mtx.Unlock()
if fc.fuzz {
return true
}
select {
case <-fc.start:
fc.fuzz = true
default:
}
return false
}
func (fc *FuzzedConnection) Read(data []byte) (n int, err error) {
if fc.Fuzz() {
return 0, nil
}
return fc.conn.Read(data)
}
func (fc *FuzzedConnection) Write(data []byte) (n int, err error) {
if fc.Fuzz() {
return 0, nil
}
return fc.conn.Write(data)
}
// Implements net.Conn
func (fc *FuzzedConnection) Close() error { return fc.conn.Close() }
func (fc *FuzzedConnection) LocalAddr() net.Addr { return fc.conn.LocalAddr() }
func (fc *FuzzedConnection) RemoteAddr() net.Addr { return fc.conn.RemoteAddr() }
func (fc *FuzzedConnection) SetDeadline(t time.Time) error { return fc.conn.SetDeadline(t) }
func (fc *FuzzedConnection) SetReadDeadline(t time.Time) error {
return fc.conn.SetReadDeadline(t)
}
func (fc *FuzzedConnection) SetWriteDeadline(t time.Time) error {
return fc.conn.SetWriteDeadline(t)
}
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