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//go:generate goderive .
//
//
// Copyright (c) 2017 anygone contributors (see AUTHORS file)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * Neither the name of anygone nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
package satp
import (
"fmt"
"net"
"sync"
"sync/atomic"
"unsafe"
)
func EndpointsEqual(this, that *net.UDPAddr) bool {
return deriveEqual(this, that)
}
type SecurityAssociation struct {
kd KeyDerivation
endpoints []*net.UDPAddr
nextSeqNr uint32
initialSeqNrInbound uint32
seqWindowSize uint
seqWindows *sync.Map
}
func (sa *SecurityAssociation) KeyGenerate(dir Direction, usage KeyUsage, sequenceNumber uint32, out []byte) error {
return sa.kd.Generate(dir, usage, sequenceNumber, out)
}
func (sa *SecurityAssociation) EndpointUpdate(idx uint, ep *net.UDPAddr) {
if idx >= uint(len(sa.endpoints)) {
return // panic???
}
atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&(sa.endpoints[idx]))), unsafe.Pointer(ep))
}
func (sa *SecurityAssociation) EndpointCompareAndUpdate(idx uint, ep *net.UDPAddr) bool {
if idx >= uint(len(sa.endpoints)) {
return false // panic???
}
old := (*net.UDPAddr)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&(sa.endpoints[idx])))))
if !EndpointsEqual(old, ep) {
atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&(sa.endpoints[idx]))), unsafe.Pointer(ep))
return true
}
return false
}
func (sa *SecurityAssociation) GetEndpointsAndNextSequenceNumber(epsIn []*net.UDPAddr) (seqNum uint32, eps []*net.UDPAddr) {
seqNum = atomic.AddUint32(&sa.nextSeqNr, 1) - 1
eps = epsIn
if eps == nil {
eps = make([]*net.UDPAddr, len(sa.endpoints))
}
for i := range sa.endpoints {
eps[i] = (*net.UDPAddr)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&(sa.endpoints[i])))))
}
return
}
func (sa *SecurityAssociation) getSequenceWindow(senderID uint16) *SequenceWindow {
win, present := sa.seqWindows.Load(senderID)
if !present {
var err error
if win, err = NewSequenceWindow(int(sa.seqWindowSize), sa.initialSeqNrInbound); err != nil {
panic(fmt.Sprint("unable to create new sequence window:", err)) // return an error instead???
}
sa.seqWindows.Store(senderID, win)
}
return win.(*SequenceWindow)
}
func (sa *SecurityAssociation) SequenceNumberCheck(senderID uint16, sequenceNumber uint32) bool {
return sa.getSequenceWindow(senderID).Check(sequenceNumber)
}
func (sa *SecurityAssociation) SequenceNumberCheckAndSet(senderID uint16, sequenceNumber uint32) bool {
return sa.getSequenceWindow(senderID).CheckAndSet(sequenceNumber)
}
func NewSecurityAssociation(kd KeyDerivation, numEndpoints uint, initialSeqNrOutbound, initialSeqNrInbound uint32, seqWindowSize uint) (sa *SecurityAssociation) {
sa = &SecurityAssociation{kd: kd}
// panic if numEndpoints == 0?
sa.endpoints = make([]*net.UDPAddr, numEndpoints)
sa.nextSeqNr = initialSeqNrOutbound
sa.initialSeqNrInbound = initialSeqNrInbound
sa.seqWindowSize = seqWindowSize
sa.seqWindows = &sync.Map{}
return
}
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