val set_pne (h: Spec.header) (#ln: pnl) (pne: PNE.pne_cipher ln) (c1: Spec.bytes)
    : Pure Spec.packet
      (requires
        not (Spec.is_retry h) /\ ln == Lib.RawIntTypes.uint_to_nat (TSpec.pn_length h) /\
        Seq.length c1 < pow2 32 - Spec.header_len_bound)
      (ensures fun r -> True)
let set_pne (h:Spec.header) (#ln:pnl) (pne:PNE.pne_cipher ln) (c1:Spec.bytes)
  : Pure Spec.packet
  (requires not (Spec.is_retry h) /\ ln == Lib.RawIntTypes.uint_to_nat (TSpec.pn_length h) /\
  Seq.length c1 < pow2 32 - Spec.header_len_bound)
  (ensures fun r -> True)
  =
  let pne, bits = pne in
  let r = TSpec.format_header h in
  let pno = TSpec.pn_offset h in
  assert(pno == Seq.length r - ln);
  assert (Seq.length r <= Spec.header_len_bound);
  assert (ln == Seq.length pne);
  let protected_bits = if Spec.MShort? h then 5 else 4 in
  let f' = BF.set_bitfield (U8.v (Seq.index r 0)) 0 protected_bits (BF.get_bitfield (U8.v (Seq.index r 0) `FStar.UInt.logxor` bits) 0 protected_bits) in
  let r' = Seq.cons (U8.uint_to_t f') (Seq.slice r 1 pno `Seq.append` Helpers.reveal pne `Seq.append` c1) in
  assert (Seq.length r' == Seq.length r + Seq.length c1);
  r'
val set_pne (h: Spec.header) (#ln: pnl) (pne: PNE.pne_cipher ln) (c1: Spec.bytes)
    : Pure Spec.packet
      (requires
        not (Spec.is_retry h) /\ ln == Lib.RawIntTypes.uint_to_nat (TSpec.pn_length h) /\
        Seq.length c1 < pow2 32 - Spec.header_len_bound)
      (ensures fun r -> True)
let set_pne (h: Spec.header) (#ln: pnl) (pne: PNE.pne_cipher ln) (c1: Spec.bytes)
    : Pure Spec.packet
      (requires
        not (Spec.is_retry h) /\ ln == Lib.RawIntTypes.uint_to_nat (TSpec.pn_length h) /\
        Seq.length c1 < pow2 32 - Spec.header_len_bound)
      (ensures fun r -> True) =
let pne, bits = pne in
let r = TSpec.format_header h in
let pno = TSpec.pn_offset h in
assert (pno == Seq.length r - ln);
assert (Seq.length r <= Spec.header_len_bound);
assert (ln == Seq.length pne);
let protected_bits = if Spec.MShort? h then 5 else 4 in
let f' =
  BF.set_bitfield (U8.v (Seq.index r 0))
    0
    protected_bits
    (BF.get_bitfield ((U8.v (Seq.index r 0)) `FStar.UInt.logxor` bits) 0 protected_bits)
in
let r' =
  Seq.cons (U8.uint_to_t f')
    (((Seq.slice r 1 pno) `Seq.append` (Helpers.reveal pne)) `Seq.append` c1)
in
assert (Seq.length r' == Seq.length r + Seq.length c1);
r'
Model.QUIC.fst.checked
Spec.Agile.Cipher.fsti.checked Spec.Agile.AEAD.fsti.checked QUIC.UInt62.fst.checked QUIC.UInt.fst.checked QUIC.TotSpec.fst.checked QUIC.Spec.Lemmas.fst.checked QUIC.Spec.Header.Parse.fsti.checked QUIC.Spec.Header.fsti.checked QUIC.Spec.fsti.checked QUIC.Secret.Int.fsti.checked prims.fst.checked Model.PNE.fsti.checked Model.Indexing.fsti.checked Model.Helpers.fsti.checked Model.AEAD.fsti.checked Mem.fst.checked LowStar.Modifies.fst.checked LowStar.Buffer.fst.checked LowParse.BitFields.fsti.checked Lib.RawIntTypes.fsti.checked FStar.UInt8.fsti.checked FStar.UInt64.fsti.checked FStar.UInt32.fsti.checked FStar.UInt128.fsti.checked FStar.UInt.fsti.checked FStar.Seq.fst.checked FStar.Pervasives.Native.fst.checked FStar.Pervasives.fsti.checked FStar.HyperStack.ST.fsti.checked FStar.HyperStack.fst.checked FStar.Endianness.fsti.checked FStar.Classical.fsti.checked
Model.QUIC.fst
QUIC.Spec.Header.Base.header Model.QUIC.pnl Model.PNE.pne_cipher QUIC.Spec.Base.bytes Model.Helpers.lbytes Model.PNE.bits Prims.unit Prims._assert Prims.eq2 Prims.int FStar.Seq.Base.length QUIC.Spec.Base.byte Prims.op_Addition FStar.Seq.Base.seq FStar.Seq.Properties.cons FStar.UInt8.uint_to_t FStar.Seq.Base.append FStar.Seq.Base.slice Model.Helpers.reveal FStar.UInt.uint_t LowParse.BitFields.set_bitfield FStar.UInt8.n FStar.UInt8.v FStar.Seq.Base.index LowParse.BitFields.get_bitfield FStar.UInt.logxor Prims.nat Prims.l_and Prims.b2t Prims.op_LessThanOrEqual QUIC.Spec.Header.Base.uu___is_MShort Prims.bool Lib.IntTypes.uint8 QUIC.Spec.Base.header_len_bound Prims.op_Subtraction QUIC.Spec.Header.Parse.pn_offset QUIC.TotSpec.pn_offset QUIC.Spec.Header.Parse.format_header QUIC.TotSpec.format_header QUIC.Spec.Crypto.packet Prims.op_Negation QUIC.Spec.Header.Base.is_retry Prims.l_or Prims.op_GreaterThanOrEqual Prims.op_Equality Lib.IntTypes.range Lib.IntTypes.U32 Lib.IntTypes.uint_v Lib.IntTypes.SEC QUIC.Spec.Header.Base.pn_length Lib.RawIntTypes.uint_to_nat Prims.op_LessThan Prims.pow2 Prims.l_True
module Model.QUIC

module HS = FStar.HyperStack
module I = Model.Indexing
module U8 = FStar.UInt8
module U32 = FStar.UInt32
module U64 = FStar.UInt64
module U128 = FStar.UInt128
module M = LowStar.Modifies

friend QUIC.TotSpec

module Spec = QUIC.Spec
module TSpec = QUIC.TotSpec
module QH = QUIC.Spec.Header
module AE = Model.AEAD
module SAE = Spec.Agile.AEAD
module PNE = Model.PNE
module SPNE = Spec.Agile.Cipher
module BF = LowParse.BitFields
module U62 = QUIC.UInt62
module Secret = QUIC.Secret.Int
module B = LowStar.Buffer

open FStar.HyperStack.ST
open FStar.UInt32
open Mem

let pne_plain (j:PNE.id) (l:pnl) : eqtype = Spec.lbytes l & PNE.length_bits l
let as_bytes (j:PNE.id) (l:pnl) (x:pne_plain j l) : GTot (Helpers.lbytes l & PNE.length_bits l) = let (n,b) = x in (Helpers.hide n, b)
let repr (j:PNE.unsafe_id) (l:pnl) (x:pne_plain j l) : b:(Helpers.lbytes l & PNE.length_bits l){b == as_bytes j l x} =
  let (n,b)=x in (Helpers.hide n, b)
let mk (j:PNE.id) (l:pnl) (n:Helpers.lbytes l) (b:PNE.length_bits l) : p:pne_plain j l{as_bytes j l p == (n,b)} = Helpers.reveal n,b

let extend (#l:pnl) (b:Spec.lbytes l) (l':pnl)
  : Spec.lbytes l' =
  if l' <= l then Seq.slice b 0 l'
  else Seq.append (Seq.create (l'-l) 0z) b

let pnenc (j:PNE.id) (l:pnl) (p:pne_plain j l) (c:PNE.pne_cipherpad)
  : (l':pnl & pne_plain j l') =
  let npn, bits = p in
  let pnm, bm = c in
  QUIC.UInt.lemma_logxor_lt #8 bits bm 5;
  let v = BF.get_bitfield #8 (bits `FStar.UInt.logxor` bm) 0 5 in
  BF.set_bitfield_bound bits 5 0 5 v;
  let bits' : PNE.bits = BF.set_bitfield bits 0 5 v in
  let ln : pnl = BF.get_bitfield bits' 0 2 + 1 in
  let npn' : Spec.lbytes ln = extend #l npn ln in    
  let npn'' = QUIC.Spec.Lemmas.xor_inplace npn' (Seq.slice (Helpers.reveal pnm) 0 ln) 0 in
  (| ln, (npn', bits') |)

let lemma_xor (j:PNE.id) (l:pnl) (p:(Spec.lbytes l & PNE.length_bits l)) (c:PNE.pne_cipherpad)
  : Lemma (requires True)
  (ensures (let (| l', b' |) = pnenc j l p c in
    let _, bits = as_bytes j l' b' in
    let l:pnl = LowParse.BitFields.get_bitfield bits 0 2 + 1 in
    l == (l' <: pnl)))
  = ()

// The (abstract) type of encrypted QUIC headers,
let pne_pkg =
  PNE.PNEPlainPkg pne_plain as_bytes repr mk pnenc lemma_xor

type _ctr (offset:pn) = p:pn{p >= offset}

noeq type stream_writer' (i:id) = 
| Writer:
  info: info ->
  offset: pn ->
  siv: Spec.lbytes 12 ->
  ae: AE.aead_writer (dfst i){(AEAD.wgetinfo ae).AEAD.min_len == 3} ->
  pne_info: PNE.info (dsnd i){
    pne_info.PNE.calg == Spec.Agile.AEAD.cipher_alg_of_supported_alg (AEAD.wgetinfo ae).AEAD.alg /\
    pne_info.PNE.halg == (AEAD.wgetinfo ae).AEAD.halg /\
    pne_info.PNE.plain == pne_pkg} ->
  pne: PNE.pne_state pne_info ->
  ctr: reference (_ctr offset) ->
  stream_writer' i

let stream_writer = stream_writer'

type _last (offset:pn) = p:nat{p >= offset /\ p < max_ctr}

noeq type stream_reader' (#i:id) (w:stream_writer i) = 
| Reader:
  aer: AE.aead_reader (w.ae) ->
  last: reference (_last w.offset) ->
  stream_reader' w

let stream_reader = stream_reader'

let writer_info #k w = w.info
let reader_info #k #w r = w.info

let writer_ae_info #k w = AEAD.wgetinfo w.ae
let reader_ae_info #k #w r = AEAD.rgetinfo r.aer
let writer_pne_info #k w = w.pne_info
let reader_pne_info #k #w r = w.pne_info

let writer_aead_state #k w = w.ae
let reader_aead_state #k #w r = r.aer

let writer_pne_state #k w = w.pne
let reader_pne_state #k #w r = w.pne

let nonce_of_ctr #i (w:stream_writer i) (n:nat{n < pow2 62 /\ n>=w.offset})
  : Tot AEAD.nonce
  =
  let _ = assert_norm(pow2 62 < pow2 (8 `op_Multiply` 12)) in
  let pn = FStar.Endianness.n_to_be 12 n in
  QUIC.Spec.Lemmas.xor_inplace pn w.siv 0

let nonce_of_ctr_injective
  #i (w:stream_writer i)
  (n1:nat{n1 < pow2 62 /\ n1>=w.offset})
  (n2:nat{n2 < pow2 62 /\ n2>=w.offset})
: Lemma
  (requires (nonce_of_ctr w n1 == nonce_of_ctr w n2))
  (ensures (n1 == n2))
=
  let _ = assert_norm(pow2 62 < pow2 (8 `op_Multiply` 12)) in
  let pn1 = FStar.Endianness.n_to_be 12 n1 in
  let pn2 = FStar.Endianness.n_to_be 12 n2 in
  QUIC.Spec.Lemmas.xor_inplace_involutive pn1 w.siv 0;
  QUIC.Spec.Lemmas.xor_inplace_involutive pn2 w.siv 0

let nonce_of_ctr_injective'
  #i (w:stream_writer i)
  (n1:nat{n1 < pow2 62 /\ n1>=w.offset})
  (n2:nat{n2 < pow2 62 /\ n2>=w.offset})
: Lemma
  (n1 <> n2 ==> nonce_of_ctr w n1 <> nonce_of_ctr w n2)
=
  Classical.move_requires (nonce_of_ctr_injective w n1) n2

let fresh_nonces_from
  (j: nat)
  (#k:id)
  (w:stream_writer k)
  (h:mem)
: GTot Type0
=
  (forall i. (i > j /\ safe k) ==>
    AEAD.fresh_nonce w.ae (nonce_of_ctr w i) h)

let fresh_nonces
  (#k:id)
  (w:stream_writer k)
  (h:mem)
: GTot Type0
= fresh_nonces_from (HS.sel h w.ctr) w h

let invariant #k w h =
  AEAD.winvariant w.ae h /\
  PNE.invariant w.pne h /\
  h `HS.contains` w.ctr /\
  fresh_nonces w h /\
  AEAD.wfootprint w.ae `B.loc_disjoint` (B.loc_mreference w.ctr) /\
  PNE.footprint w.pne `B.loc_disjoint` (B.loc_mreference w.ctr) /\
  PNE.footprint w.pne `B.loc_disjoint` AEAD.wfootprint w.ae

let rinvariant #k #w r h = invariant w h /\
  h `HS.contains` r.last /\
  AEAD.wfootprint w.ae `B.loc_disjoint` (B.loc_mreference w.ctr)

let writer_offset #k w = w.offset
let reader_offset #k #w r = w.offset

let wctrT #k w h = HS.sel h w.ctr
let wctr #k w = !w.ctr

let writer_static_iv #k w = w.siv
let reader_static_iv #k #w r = w.siv

let expected_pnT #k #w r h = HS.sel h r.last
let expected_pn #k #w r = !r.last

let footprint #k w = (AEAD.wfootprint w.ae)
  `B.loc_union` (PNE.footprint w.pne)
  `B.loc_union` B.loc_mreference w.ctr

let rfootprint #k #w r = footprint w `B.loc_union` B.loc_mreference r.last

let frame_invariant #k w h0 l h1 =
  AEAD.wframe_invariant l w.ae h0 h1;
  PNE.frame_invariant w.pne l h0 h1;
  if safe k then AEAD.frame_log l w.ae h0 h1

let rframe_invariant #k #w r h0 l h1 =
  AEAD.wframe_invariant l w.ae h0 h1;
  PNE.frame_invariant w.pne l h0 h1

let wframe_log #k w t h0 l h1 =
  AEAD.frame_log l w.ae h0 h1
  
let rframe_log #k #w r t h0 l h1 =
  AEAD.frame_log l w.ae h0 h1

let wframe_pnlog #k w t h0 l h1 =
  PNE.frame_table w.pne l h0 h1

let rframe_pnlog #k #w r t h0 l h1 =
  PNE.frame_table w.pne l h0 h1

(* HACK, the interleaving of `val coerce` into this file fails to verify
without increasing the rlimit, but increasing it in the fsti wouldn't
take effect here (see FStar issue #2854 and the others linked from
there. So, increase rlimit here and pop it after `let coerce`, so we are
sure to catch it. *)
#push-options "--z3rlimit 40"

let create k u u1 u2 init =
  let open Model.Helpers in
  let alg = u1.AEAD.alg in
  let siv = random 12 in
  (**) let h0 = get() in
  let ae = AEAD.gen (dfst k) u1 in
  (**) let h1 = get () in  
  let pne = PNE.create (dsnd k) u2 in
  (**) let h2 = get () in
  let ctr = ralloc u.region init in
  (**) let h3 = get () in 
  (**) AEAD.wframe_invariant M.loc_none ae h1 h3;
  (**) PNE.frame_invariant pne M.loc_none h2 h3;
  if safe k then
   begin
    (**) AEAD.frame_log M.loc_none ae h1 h3;
    (**) PNE.frame_table pne M.loc_none h2 h3
   end;
  Writer u init (reveal siv) ae u2 pne ctr

let coerce k u u1 u2 init ts =
  let open Model.Helpers in
  let alg = u1.AEAD.alg in
  let siv : Model.Helpers.lbytes 12 = Spec.derive_secret u1.AEAD.halg ts Spec.label_iv 12 in
  let h0 = get() in
  let u1 : AEAD.info (dfst k) = u1 in
  let ae = AEAD.quic_coerce u1 ts in
  let h1 = get () in
  let pne = PNE.quic_coerce (dsnd k) u2 ts in
  let h2 = get () in
  let ctr = ralloc u.region init in
  let h3 = get () in 
  AEAD.wframe_invariant M.loc_none ae h1 h3;
  PNE.frame_invariant pne M.loc_none h2 h3;
  Writer u init (reveal siv) ae u2 pne ctr

#push-options "--z3rlimit 400 --query_stats"

let createReader rgn #k w =
  let h0 = get () in
  let last = ralloc rgn (writer_offset w) in
  let h1 = get () in
  frame_invariant w h0 M.loc_none h1;
  let aer = AEAD.gen_reader w.ae in
  Reader aer last

(* Another HACK: set_pn gets interleaved here *)

#pop-options
#pop-options

#push-options "--z3rlimit 256 --fuel 0"
private let lemma_eq_add (a b c:nat) : Lemma (requires a == b - c)
  (ensures a + c == b) = ()

let set_pne (h:Spec.header) (#ln:pnl) (pne:PNE.pne_cipher ln) (c1:Spec.bytes)
  : Pure Spec.packet
  (requires not (Spec.is_retry h) /\ ln == Lib.RawIntTypes.uint_to_nat (TSpec.pn_length h) /\
  Seq.length c1 < pow2 32 - Spec.header_len_bound)
val set_pne (h: Spec.header) (#ln: pnl) (pne: PNE.pne_cipher ln) (c1: Spec.bytes)
    : Pure Spec.packet
      (requires
        not (Spec.is_retry h) /\ ln == Lib.RawIntTypes.uint_to_nat (TSpec.pn_length h) /\
        Seq.length c1 < pow2 32 - Spec.header_len_bound)
      (ensures fun r -> True)
h: QUIC.Spec.Header.Base.header -> pne: Model.PNE.pne_cipher ln -> c1: QUIC.Spec.Base.bytes
  -> Prims.Pure QUIC.Spec.Crypto.packet