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Drop explicit underlying buffer parameters #358

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Drop explicit underlying buffer parameters #358

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189bfc4
simplify path
jcp19 Jun 14, 2024
271bb5a
path ready
Dspil Jun 27, 2024
df41cbc
preserves
Dspil Jun 27, 2024
181a99a
Merge branch 'master' into remove-ubs
Dspil Jun 27, 2024
3d041c4
Merge branch 'master' into remove-ubs
jcp19 Jul 18, 2024
b26935f
Merge branch 'master' into remove-ubs
jcp19 Sep 11, 2024
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101 changes: 57 additions & 44 deletions pkg/slayers/path/path.go
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Original file line number Diff line number Diff line change
Expand Up @@ -64,67 +64,77 @@ func (t Type) String() string {
// Path is the path contained in the SCION header.
type Path interface {
// (VerifiedSCION) Must hold for every valid Path.
//@ pred Mem(ub []byte)
//@ pred Mem()
// (VerifiedSCION) Must imply the resources required to initialize
// a new instance of a predicate.
//@ pred NonInitMem()
// SerializeTo serializes the path into the provided buffer.
// (VerifiedSCION) There are implementations of this interface that modify the underlying
// structure when serializing (e.g. scion.Raw)
//@ preserves sl.Bytes(ub, 0, len(ub))
//@ preserves acc(Mem(ub), R1)
//@ preserves sl.Bytes(b, 0, len(b))
//@ ensures e != nil ==> e.ErrorMem()
//@ decreases
SerializeTo(b []byte /*@, ghost ub []byte @*/) (e error)
// @ preserves acc(Mem(), R1)
// @ preserves sl.Bytes(RawBytes(), 0, len(RawBytes()))
// @ preserves sl.Bytes(b, 0, len(b))
// @ ensures e != nil ==> e.ErrorMem()
// @ ensures RawBytes() === old(RawBytes())
// @ decreases
SerializeTo(b []byte) (e error)
// DecodesFromBytes decodes the path from the provided buffer.
// (VerifiedSCION) There are implementations of this interface (e.g., scion.Raw) that
// store b and use it as internal data.
//@ requires NonInitMem()
//@ preserves acc(sl.Bytes(b, 0, len(b)), R42)
//@ ensures err == nil ==> Mem(b)
//@ ensures err == nil ==>
//@ Mem() && RawBytes() === b
//@ ensures err != nil ==> err.ErrorMem()
//@ ensures err != nil ==> NonInitMem()
//@ ensures err == nil ==> IsValidResultOfDecoding(b, err)
//@ ensures err == nil ==> IsValidResultOfDecoding(err)
//@ decreases
DecodeFromBytes(b []byte) (err error)
//@ ghost
//@ pure
//@ requires Mem(b)
//@ requires acc(sl.Bytes(b, 0, len(b)), R42)
//@ requires Mem()
//@ requires acc(sl.Bytes(RawBytes(), 0, len(RawBytes())), R42)
//@ decreases
//@ IsValidResultOfDecoding(b []byte, err error) (res bool)
//@ IsValidResultOfDecoding(err error) (res bool)
// Reverse reverses a path such that it can be used in the reversed direction.
// XXX(shitz): This method should possibly be moved to a higher-level path manipulation package.
//@ requires Mem(ub)
//@ preserves sl.Bytes(ub, 0, len(ub))
//@ ensures e == nil ==> p != nil
//@ ensures e == nil ==> p.Mem(ub)
//@ ensures e != nil ==> e.ErrorMem()
//@ decreases
Reverse( /*@ ghost ub []byte @*/ ) (p Path, e error)
// @ preserves Mem()
// @ preserves sl.Bytes(RawBytes(), 0, len(RawBytes()))
// @ ensures e == nil ==>
// @ p != nil &&
// @ p.Mem() &&
// @ p.RawBytes() === RawBytes()
// @ ensures old(RawBytes()) === RawBytes()
// @ ensures e != nil ==> e.ErrorMem()
// @ decreases
Reverse() (p Path, e error)
//@ ghost
//@ pure
//@ requires acc(Mem(ub), _)
//@ requires acc(Mem(), _)
//@ ensures 0 <= l
//@ decreases
//@ LenSpec(ghost ub []byte) (l int)

//@ LenSpec() (l int)
// Len returns the length of a path in bytes.
//@ preserves acc(Mem(ub), R50)
//@ ensures l == LenSpec(ub)
//@ preserves acc(Mem(), R50)
//@ ensures l == LenSpec()
//@ decreases
Len( /*@ ghost ub []byte @*/ ) (l int)
Len() (l int)
// Type returns the type of a path.
//@ pure
//@ requires acc(Mem(ub), _)
//@ requires acc(Mem(), _)
//@ decreases
Type( /*@ ghost ub []byte @*/ ) Type
Type() Type
//@ ghost
//@ requires Mem(ub)
//@ requires Mem()
//@ ensures NonInitMem()
//@ decreases
//@ DowngradePerm(ghost ub []byte)
//@ DowngradePerm()

//@ ghost
//@ pure
//@ requires acc(Mem(), _)
//@ decreases
//@ RawBytes() (res []byte)
}

type metadata struct {
Expand Down Expand Up @@ -215,50 +225,53 @@ type rawPath struct {
pathType Type
}

// @ preserves acc(p.Mem(ub), R10)
// @ preserves acc(sl.Bytes(ub, 0, len(ub)), R10)
// @ preserves acc(p.Mem(), R10)
// @ preserves let raw := p.RawBytes() in
// @ acc(sl.Bytes(raw, 0, len(raw)), R10)
// @ preserves sl.Bytes(b, 0, len(b))
// @ ensures e == nil
// @ ensures p.RawBytes() === old(p.RawBytes())
// @ decreases
func (p *rawPath) SerializeTo(b []byte /*@, ghost ub []byte @*/) (e error) {
func (p *rawPath) SerializeTo(b []byte) (e error) {
//@ unfold sl.Bytes(b, 0, len(b))
//@ unfold acc(p.Mem(ub), R10)
//@ unfold acc(p.Mem(), R10)
//@ unfold acc(sl.Bytes(p.raw, 0, len(p.raw)), R11)
copy(b, p.raw /*@, R11 @*/)
//@ fold acc(sl.Bytes(p.raw, 0, len(p.raw)), R11)
//@ fold acc(p.Mem(ub), R10)
//@ fold acc(p.Mem(), R10)
//@ fold sl.Bytes(b, 0, len(b))
return nil
}

// @ requires p.NonInitMem()
// @ preserves acc(sl.Bytes(b, 0, len(b)), R42)
// @ ensures p.Mem(b)
// @ ensures p.Mem()
// @ ensures p.RawBytes() === b
// @ ensures e == nil
// @ decreases
func (p *rawPath) DecodeFromBytes(b []byte) (e error) {
//@ unfold p.NonInitMem()
p.raw = b
//@ fold p.Mem(b)
//@ fold p.Mem()
return nil
}

// @ ensures e != nil && e.ErrorMem()
// @ decreases
func (p *rawPath) Reverse( /*@ ghost ub []byte @*/ ) (r Path, e error) {
func (p *rawPath) Reverse() (r Path, e error) {
return nil, serrors.New("not supported")
}

// @ preserves acc(p.Mem(ub), R50)
// @ ensures l == p.LenSpec(ub)
// @ preserves acc(p.Mem(), R50)
// @ ensures l == p.LenSpec()
// @ decreases
func (p *rawPath) Len( /*@ ghost ub []byte @*/ ) (l int) {
return /*@ unfolding acc(p.Mem(ub), R50) in @*/ len(p.raw)
func (p *rawPath) Len() (l int) {
return /*@ unfolding acc(p.Mem(), _) in @*/ len(p.raw)
}

// @ pure
// @ requires acc(p.Mem(ub), _)
// @ requires acc(p.Mem(), _)
// @ decreases
func (p *rawPath) Type( /*@ ghost ub []byte @*/ ) Type {
return /*@ unfolding acc(p.Mem(ub), _) in @*/ p.pathType
func (p *rawPath) Type() Type {
return /*@ unfolding acc(p.Mem(), _) in @*/ p.pathType
}
27 changes: 17 additions & 10 deletions pkg/slayers/path/path_spec.gobra
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Original file line number Diff line number Diff line change
Expand Up @@ -19,38 +19,45 @@ package path
import "github.com/scionproto/scion/verification/utils/slices"

/** rawPath spec **/
pred (r *rawPath) Mem(underlyingBuf []byte) {
acc(r) &&
r.raw === underlyingBuf
pred (r *rawPath) Mem() {
acc(r)
}

pred (r *rawPath) NonInitMem() {
acc(r)
}

ghost
requires p.Mem(buf)
requires p.Mem()
ensures p.NonInitMem()
decreases
func (p *rawPath) DowngradePerm(ghost buf []byte) {
unfold p.Mem(buf)
func (p *rawPath) DowngradePerm() {
unfold p.Mem()
fold p.NonInitMem()
}

ghost
pure
decreases
func (p *rawPath) IsValidResultOfDecoding(b []byte, err error) (res bool) {
func (p *rawPath) IsValidResultOfDecoding(err error) (res bool) {
return true
}

ghost
pure
requires acc(p.Mem(ub), _)
requires acc(p.Mem(), _)
decreases
func (p *rawPath) RawBytes() (res []byte) {
return unfolding acc(p.Mem(), _) in p.raw
}

ghost
pure
requires acc(p.Mem(), _)
ensures 0 <= l
decreases
func (p *rawPath) LenSpec(ghost ub []byte) (l int) {
return unfolding acc(p.Mem(ub), _) in len(p.raw)
func (p *rawPath) LenSpec() (l int) {
return unfolding acc(p.Mem(), _) in len(p.raw)
}

(*rawPath) implements Path
Expand Down
2 changes: 1 addition & 1 deletion pkg/slayers/path/path_spec_test.gobra
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ import sl "github.com/scionproto/scion/verification/utils/slices"
func foldMem_test() {
r := &rawPath{}
fold sl.Bytes(r.raw, 0, 0)
fold r.Mem(nil)
fold r.Mem()
}

func foldNonInitMem_test() {
Expand Down
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