feat(p2p): CORE_SYNC_DATA type and command ID constants

Add CoreSyncData with MarshalSection/UnmarshalSection for portable
storage roundtrip. Re-export Levin command IDs for the CryptoNote
P2P protocol layer.

Co-Authored-By: Charon <charon@lethean.io>

go.mod

@@ -1,8 +1,11 @@
 module forge.lthn.ai/core/go-blockchain
 
-go 1.25
+go 1.25.5
 
-require golang.org/x/crypto v0.48.0
+require (
+	forge.lthn.ai/core/go-p2p v0.0.0-00010101000000-000000000000
+	golang.org/x/crypto v0.48.0
+)
 
 require golang.org/x/sys v0.41.0 // indirect
 

go.sum

@@ -1,4 +1,12 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 golang.org/x/crypto v0.48.0 h1:/VRzVqiRSggnhY7gNRxPauEQ5Drw9haKdM0jqfcCFts=
 golang.org/x/crypto v0.48.0/go.mod h1:r0kV5h3qnFPlQnBSrULhlsRfryS2pmewsg+XfMgkVos=
 golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
 golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

p2p/commands.go

@@ -0,0 +1,22 @@
+// Copyright (c) 2017-2026 Lethean (https://lt.hn)
+//
+// Licensed under the European Union Public Licence (EUPL) version 1.2.
+// SPDX-License-Identifier: EUPL-1.2
+
+// Package p2p implements the CryptoNote P2P protocol for the Lethean blockchain.
+package p2p
+
+import "forge.lthn.ai/core/go-p2p/node/levin"
+
+// Re-export command IDs from the levin package for convenience.
+const (
+	CommandHandshake       = levin.CommandHandshake
+	CommandTimedSync       = levin.CommandTimedSync
+	CommandPing            = levin.CommandPing
+	CommandNewBlock        = levin.CommandNewBlock
+	CommandNewTransactions = levin.CommandNewTransactions
+	CommandRequestObjects  = levin.CommandRequestObjects
+	CommandResponseObjects = levin.CommandResponseObjects
+	CommandRequestChain    = levin.CommandRequestChain
+	CommandResponseChain   = levin.CommandResponseChain
+)

p2p/sync.go

@@ -0,0 +1,82 @@
+// Copyright (c) 2017-2026 Lethean (https://lt.hn)
+//
+// Licensed under the European Union Public Licence (EUPL) version 1.2.
+// SPDX-License-Identifier: EUPL-1.2
+
+package p2p
+
+import (
+	"forge.lthn.ai/core/go-blockchain/types"
+	"forge.lthn.ai/core/go-p2p/node/levin"
+)
+
+// CoreSyncData is the blockchain state exchanged during handshake and timed sync.
+type CoreSyncData struct {
+	CurrentHeight        uint64
+	TopID                types.Hash
+	LastCheckpointHeight uint64
+	CoreTime             uint64
+	ClientVersion        string
+	NonPruningMode       bool
+}
+
+// MarshalSection encodes CoreSyncData into a portable storage Section.
+func (d *CoreSyncData) MarshalSection() levin.Section {
+	return levin.Section{
+		"current_height":           levin.Uint64Val(d.CurrentHeight),
+		"top_id":                   levin.StringVal(d.TopID[:]),
+		"last_checkpoint_height":   levin.Uint64Val(d.LastCheckpointHeight),
+		"core_time":               levin.Uint64Val(d.CoreTime),
+		"client_version":          levin.StringVal([]byte(d.ClientVersion)),
+		"non_pruning_mode_enabled": levin.BoolVal(d.NonPruningMode),
+	}
+}
+
+// UnmarshalSection decodes CoreSyncData from a portable storage Section.
+func (d *CoreSyncData) UnmarshalSection(s levin.Section) error {
+	if v, ok := s["current_height"]; ok {
+		val, err := v.AsUint64()
+		if err != nil {
+			return err
+		}
+		d.CurrentHeight = val
+	}
+	if v, ok := s["top_id"]; ok {
+		blob, err := v.AsString()
+		if err != nil {
+			return err
+		}
+		if len(blob) == 32 {
+			copy(d.TopID[:], blob)
+		}
+	}
+	if v, ok := s["last_checkpoint_height"]; ok {
+		val, err := v.AsUint64()
+		if err != nil {
+			return err
+		}
+		d.LastCheckpointHeight = val
+	}
+	if v, ok := s["core_time"]; ok {
+		val, err := v.AsUint64()
+		if err != nil {
+			return err
+		}
+		d.CoreTime = val
+	}
+	if v, ok := s["client_version"]; ok {
+		blob, err := v.AsString()
+		if err != nil {
+			return err
+		}
+		d.ClientVersion = string(blob)
+	}
+	if v, ok := s["non_pruning_mode_enabled"]; ok {
+		val, err := v.AsBool()
+		if err != nil {
+			return err
+		}
+		d.NonPruningMode = val
+	}
+	return nil
+}

p2p/sync_test.go

@@ -0,0 +1,59 @@
+// Copyright (c) 2017-2026 Lethean (https://lt.hn)
+//
+// Licensed under the European Union Public Licence (EUPL) version 1.2.
+// SPDX-License-Identifier: EUPL-1.2
+
+package p2p
+
+import (
+	"testing"
+
+	"forge.lthn.ai/core/go-blockchain/types"
+	"forge.lthn.ai/core/go-p2p/node/levin"
+)
+
+func TestCoreSyncData_Good_Roundtrip(t *testing.T) {
+	var topID types.Hash
+	topID[0] = 0xCB
+	topID[31] = 0x63
+
+	original := CoreSyncData{
+		CurrentHeight:        6300,
+		TopID:                topID,
+		LastCheckpointHeight: 0,
+		CoreTime:             1708444800,
+		ClientVersion:        "Lethean/go-blockchain 0.1.0",
+		NonPruningMode:       true,
+	}
+	section := original.MarshalSection()
+	data, err := levin.EncodeStorage(section)
+	if err != nil {
+		t.Fatalf("encode: %v", err)
+	}
+	decoded, err := levin.DecodeStorage(data)
+	if err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	var got CoreSyncData
+	if err := got.UnmarshalSection(decoded); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if got.CurrentHeight != original.CurrentHeight {
+		t.Errorf("height: got %d, want %d", got.CurrentHeight, original.CurrentHeight)
+	}
+	if got.TopID != original.TopID {
+		t.Errorf("top_id: got %x, want %x", got.TopID, original.TopID)
+	}
+	if got.ClientVersion != original.ClientVersion {
+		t.Errorf("version: got %q, want %q", got.ClientVersion, original.ClientVersion)
+	}
+	if got.NonPruningMode != original.NonPruningMode {
+		t.Errorf("pruning: got %v, want %v", got.NonPruningMode, original.NonPruningMode)
+	}
+	if got.LastCheckpointHeight != original.LastCheckpointHeight {
+		t.Errorf("checkpoint: got %d, want %d", got.LastCheckpointHeight, original.LastCheckpointHeight)
+	}
+	if got.CoreTime != original.CoreTime {
+		t.Errorf("core_time: got %d, want %d", got.CoreTime, original.CoreTime)
+	}
+}