117 lines
3.6 KiB
Go
117 lines
3.6 KiB
Go
package localreset
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import (
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"bufio"
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"bytes"
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"context"
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"encoding/json"
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"errors"
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"io"
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"git.pcux.cn/xuans/Scert/backend/internal/deployment"
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)
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const (
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inspectionPartSize = 8 << 10
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maxInspectionParts = 48
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maxInspectionBytes = inspectionPartSize * maxInspectionParts
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maxInspectionPathBytes = 4096 + len(".scert-backup-") + 160
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)
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// 单帧仍限制为 16 KiB；总量覆盖十二条最长路径经 JSON 六倍转义后的大小。
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// 分片不增加业务请求次数，不重复采样；任何缺片、乱序或超限均不返回部分核查结果。
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type inspectionPart struct {
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Index int `json:"index"`
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Total int `json:"total"`
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Data []byte `json:"data"`
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}
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func validInspectionPayload(value *deployment.RecoveryInspection) bool {
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if value == nil || !validRecoveryID(value.TransactionID) || len(value.Files) != 9 || len(value.Locks) != 3 || value.ObservedAt.IsZero() {
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return false
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}
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for _, file := range value.Files {
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if len(file.Path) > maxInspectionPathBytes {
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return false
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}
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}
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for _, lock := range value.Locks {
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if len(lock.Path) > maxInspectionPathBytes {
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return false
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}
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}
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return true
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}
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func writeRecoveryResponse(ctx context.Context, writer io.Writer, response Response) error {
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if err := ctx.Err(); err != nil {
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return err
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}
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if response.Inspection == nil {
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return writeFrame(writer, response)
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}
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if !validInspectionPayload(response.Inspection) || response.InspectionPart != nil || response.RecoveryPage != nil || hasDispositionPayload(response) {
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return ErrProtocol
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}
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encoded, err := json.Marshal(response)
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if err != nil {
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return ErrProtocol
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}
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if len(encoded)+1 <= MaxFrameSize {
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return writeFrame(writer, response)
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}
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data, err := json.Marshal(response.Inspection)
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if err != nil || len(data) > maxInspectionBytes {
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return ErrProtocol
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}
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total := (len(data) + inspectionPartSize - 1) / inspectionPartSize
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response.Inspection = nil
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for index := 0; index < total; index++ {
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if err := ctx.Err(); err != nil {
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return err
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}
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start := index * inspectionPartSize
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end := min(start+inspectionPartSize, len(data))
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response.InspectionPart = &inspectionPart{Index: index, Total: total, Data: data[start:end]}
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if err := writeFrame(writer, response); err != nil {
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return err
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}
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}
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return nil
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}
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func readInspectionParts(reader *bufio.Reader, first Response) (*deployment.RecoveryInspection, error) {
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if first.InspectionPart == nil || first.InspectionPart.Total < 1 || first.InspectionPart.Total > maxInspectionParts {
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return nil, ErrProtocol
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}
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total := first.InspectionPart.Total
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data := make([]byte, 0, total*inspectionPartSize)
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response := first
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for index := 0; index < total; index++ {
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if index > 0 {
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response = Response{}
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if err := readFrame(reader, &response); err != nil {
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return nil, ErrProtocol
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}
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}
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part := response.InspectionPart
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if !validChallenge(response) || response.Nonce != first.Nonce || len(response.Methods) != 0 || response.RecoveryAvailable || hasDispositionPayload(response) ||
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response.Inspection != nil || response.RecoveryPage != nil || part == nil || part.Index != index || part.Total != total ||
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len(part.Data) == 0 || len(part.Data) > inspectionPartSize || (index < total-1 && len(part.Data) != inspectionPartSize) {
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return nil, ErrProtocol
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}
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data = append(data, part.Data...)
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}
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var inspection deployment.RecoveryInspection
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decoder := json.NewDecoder(bytes.NewReader(data))
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decoder.DisallowUnknownFields()
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if decoder.Decode(&inspection) != nil || !validInspectionPayload(&inspection) {
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return nil, ErrProtocol
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}
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var extra any
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if !errors.Is(decoder.Decode(&extra), io.EOF) {
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return nil, ErrProtocol
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}
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return &inspection, nil
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}
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