| 1 | package host |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "crypto/sha256" |
| 6 | "encoding/hex" |
| 7 | "fmt" |
| 8 | |
| 9 | "github.com/carlosframework/platform/internal/hostbox" |
| 10 | "github.com/carlosframework/platform/internal/hostclaim" |
| 11 | "github.com/carlosframework/platform/internal/hostguard" |
| 12 | ) |
| 13 | |
| 14 | // relocationCompletedHandover is the first serving cold wake after a |
| 15 | // relocation completed on this box (rulings 49 and 56; Astra round 2 |
| 16 | // finding 6). The predecessor is the probe session S that the target |
| 17 | // stopped at relocating/probing with root's writer-session receipt, and |
| 18 | // the serving op journals that stop (CompletedRelocation). Nothing is |
| 19 | // stopped again and nothing is relabelled: before admission the receipt |
| 20 | // is found and verified in this box's guard journal (in place of main's |
| 21 | // Wake.Stop, which would ask a serving-shaped re-stop of S); after |
| 22 | // admission it is handed to root's ColdHandover.Run as the exact prior, |
| 23 | // which Run accepts beside the separately validated successor without |
| 24 | // matching their operation ids. |
| 25 | type relocationCompletedHandover struct { |
| 26 | Guard hostguard.Guard |
| 27 | Identity hostbox.IdentityProvider |
| 28 | Socket string |
| 29 | Box string |
| 30 | } |
| 31 | |
| 32 | // completedPrior reports whether prior is a serving claim whose writer is |
| 33 | // the stopped probe session this box completed a relocation with. A |
| 34 | // serving claim on this box whose completion record is present but cannot |
| 35 | // be read is an error, never "not the completed prior" (absence is never |
| 36 | // evidence): routed to main's stop it would re-stop S with a serving-shaped |
| 37 | // fence that replaces the probe's. |
| 38 | func (h relocationCompletedHandover) completedPrior(prior hostclaim.Observed) (hostclaim.CompletedRelocation, bool, error) { |
| 39 | c := prior.Claim |
| 40 | if c == nil || c.Holder == nil || c.Op.Kind != hostclaim.KindServing || c.Op.Exec != h.Box || c.Holder.WriterBox != h.Box { |
| 41 | return hostclaim.CompletedRelocation{}, false, nil |
| 42 | } |
| 43 | done, ok, err := hostclaim.ReadCompletedRelocation(c) |
| 44 | if err != nil { |
| 45 | return hostclaim.CompletedRelocation{}, false, err |
| 46 | } |
| 47 | if !ok || done.Stop.Box != h.Box || done.Stop.Session != c.Holder.Session || done.Stamp != c.Holder.Stamp || done.Generation != c.Holder.Generation { |
| 48 | return hostclaim.CompletedRelocation{}, false, nil |
| 49 | } |
| 50 | return done, true, nil |
| 51 | } |
| 52 | |
| 53 | // receipt is root's completed writer-session stop of S, exactly the one |
| 54 | // the serving op journals: fence id, phase and the receipt bytes' digest. |
| 55 | func (h relocationCompletedHandover) receipt(ctx context.Context, prior hostclaim.Observed) (hostguard.FenceReceipt, error) { |
| 56 | done, ok, err := h.completedPrior(prior) |
| 57 | if err != nil { |
| 58 | return hostguard.FenceReceipt{}, err |
| 59 | } |
| 60 | if !ok { |
| 61 | return hostguard.FenceReceipt{}, hostbox.ErrChanged |
| 62 | } |
| 63 | r, err := writerSessionReceipt(ctx, h.Guard, prior.Host, hostguard.Captured{Incarnation: prior.Claim.Holder.Incarnation, Stamp: done.Stamp}, done.Op, h.Box, done.Stop.Session) |
| 64 | if err != nil { |
| 65 | return hostguard.FenceReceipt{}, err |
| 66 | } |
| 67 | sum := sha256.Sum256(r.Bytes) |
| 68 | if r.Target.FenceID != done.Stop.Receipt || r.Target.Phase != done.Phase || hex.EncodeToString(sum[:]) != done.Stop.ReceiptSHA256 { |
| 69 | return hostguard.FenceReceipt{}, fmt.Errorf("%w: session %d's stop under %s is not the one the serving op records", ErrClaimStopReceipt, done.Stop.Session, done.Op) |
| 70 | } |
| 71 | return r, nil |
| 72 | } |
| 73 | |
| 74 | // writerSessionReceipt is root's completed writer-session stop of session |
| 75 | // (hostguard.WriterStopObligation) for op on box, from this box's guard |
| 76 | // journal: the one reader of a probe's stop, for the probe stop and for |
| 77 | // the serving handover after it. Two different completed stops of the |
| 78 | // same session under the same op are a defect of the journal, refused as |
| 79 | // main's CompletedColdPredecessor refuses them (ErrFenceTarget): neither |
| 80 | // is "the" receipt, and the stop never guesses which to record. |
| 81 | func writerSessionReceipt(ctx context.Context, guard hostguard.Guard, host string, captured hostguard.Captured, op, box string, session uint64) (hostguard.FenceReceipt, error) { |
| 82 | receipts, err := guard.CompletedWriterStops(ctx, host, captured, op, box) |
| 83 | if err != nil { |
| 84 | return hostguard.FenceReceipt{}, err |
| 85 | } |
| 86 | want := hostguard.WriterStopObligation(session) |
| 87 | var found hostguard.FenceReceipt |
| 88 | for _, r := range receipts { |
| 89 | if r.Target.Session != session || r.Target.ObligationID != want { |
| 90 | continue |
| 91 | } |
| 92 | if found.Target.FenceID != "" && found.Target != r.Target { |
| 93 | return hostguard.FenceReceipt{}, fmt.Errorf("%w: root completed more than one stop of session %d under %s", hostguard.ErrFenceTarget, session, op) |
| 94 | } |
| 95 | found = r |
| 96 | } |
| 97 | if found.Target.FenceID == "" { |
| 98 | return hostguard.FenceReceipt{}, fmt.Errorf("%w: root has no completed stop of session %d under %s", ErrClaimStopReceipt, session, op) |
| 99 | } |
| 100 | return found, nil |
| 101 | } |
| 102 | |
| 103 | // Before replaces the predecessor stop for exactly this prior: the stop |
| 104 | // already happened, so its receipt is found and verified, nothing more. |
| 105 | func (h relocationCompletedHandover) Before(ctx context.Context, prior hostclaim.Observed) error { |
| 106 | r, err := h.receipt(ctx, prior) |
| 107 | if err != nil { |
| 108 | return err |
| 109 | } |
| 110 | return verifyRetirementReceipt(ctx, r) |
| 111 | } |
| 112 | |
| 113 | // After is main's cold handover with that receipt as the prior. |
| 114 | func (h relocationCompletedHandover) After() func(context.Context, hostclaim.Observed, hostclaim.Observed) error { |
| 115 | return coldHandoverWith(h.Identity, h.Socket, h.receipt) |
| 116 | } |
| 117 | |
amadan