init: v1.0.0

2026-05-27 23:03:00 +08:00
commit 8d97f750eb
466 changed files with 80067 additions and 0 deletions
@@ -0,0 +1,179 @@
+package entropy
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"errors"
+	"sync"
+	"time"
+
+	"xdx.jelly/xgcl/grand/drng/internal"
+)
+
+var OutOfEntropyErr = errors.New("out of entropy")
+
+// Read reads at most 32 bytes into p.
+// For efficiency, reads bytes are always multiples of 4.
+func (e *EntropyPool) Read(p []byte) (int, error) {
+	entropyPool.mu.Lock()
+
+	if entropyPool.entropySize <= 0 {
+		return 0, OutOfEntropyErr
+	}
+	// n = min(8, entropyPool.entropySize, len(p) / 4)
+	n := 8
+	if entropyPool.entropySize < 8 {
+		n = entropyPool.entropySize
+	}
+
+	if (len(p) / 4) < n {
+		n = len(p) / 4
+	}
+
+	for i := 0; i < n; i++ {
+		x, _ := entropyPool.get() // err should not happen
+		binary.BigEndian.PutUint32(p[4*i:], x)
+	}
+
+	entropyPool.mu.Unlock()
+
+	go e.update() // update the entropy pool for next reading.
+
+	return 4 * n, nil
+}
+
+// EntropyPool 系统熵池
+type EntropyPool struct {
+	mu   sync.Mutex  //使用互斥锁保证独占性
+	pool [128]uint32 //熵池，128个字（512字节）
+	// i - j 之间是未取的熵(mod 128)
+	i           int //熵索引开始
+	j           int //熵索引结束
+	entropySize int //熵池中可用熵值
+	source      []EntropySource
+}
+
+// entropySource 熵源
+type EntropySource interface {
+	GetEntropy(minEntropy int64, minEntropyInputLength int64, maxEntropyInputLength int64) ([]byte, error)
+}
+
+var entropyPool *EntropyPool
+var initEntropyPool sync.Once
+
+func init() {
+	initEntropyPool.Do(
+		func() {
+			entropyPool = newEntropyPool()
+		})
+	go func() {
+		// 定时从系统中获取
+		tickle := time.NewTicker(10 * time.Second)
+		for {
+			select {
+			case <-tickle.C:
+				entropyPool.update()
+			}
+		}
+	}()
+}
+
+func GetEntropyPool() *EntropyPool {
+	return entropyPool
+}
+
+func newEntropyPool() *EntropyPool {
+	// FIXME: SysTimeEntropySource？
+	p := &EntropyPool{
+		source: []EntropySource{&OSEntropySource{}, &SysTimeEntropySource{}},
+		// source: []drng.EntropySource{&OSEntropySource{}},
+	}
+
+	buf := make([]byte, 128*4)
+	_, _ = rand.Reader.Read(buf)
+	for i := 0; i < 128; i++ {
+		p.pool[i] = binary.BigEndian.Uint32(buf[4*i:])
+	}
+
+	// 从每个熵源获取至少256比特
+	p.update()
+
+	// 对buf置0
+	for i := range buf {
+		buf[i] = 0
+	}
+	// for i := range e {
+	// 	e[i] = 0
+	// }
+	return p
+}
+
+func (e *EntropyPool) get() (uint32, error) {
+	if e.entropySize <= 0 {
+		return 0, OutOfEntropyErr
+	}
+	n := e.pool[e.i]
+	e.i = (e.i + 1) & 127
+	e.entropySize--
+	return n, nil
+}
+
+// lshr 添加新的熵数据g到熵池中。按照GM/T 0105 A.3的方式
+func (e *EntropyPool) lshr(g uint32) {
+	var table = [8]uint32{0, 0x3b6e20c8, 0x76dc4190, 0x4db26158, 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278}
+	temp := g ^ e.pool[e.j]
+	for _, i := range []int{1, 25, 51, 76, 103} {
+		temp ^= e.pool[(e.j+i)&127]
+	}
+	temp = (temp >> 3) ^ table[temp&7]
+	e.pool[e.j] = temp
+	e.j = (e.j + 1) & 127
+
+	// 置0
+	temp = 0
+	_ = temp
+}
+
+// Update 熵池更新
+func (e *EntropyPool) update() {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	// 设置超时时间
+	tickle := time.NewTicker(100 * time.Millisecond)
+	defer tickle.Stop()
+
+	for i := 0; e.entropySize < 128; i = (i + 1) % len(e.source) {
+		select {
+		case <-tickle.C:
+			break
+		default:
+			s := e.source[i]
+			b, _ := s.GetEntropy(4, 4, internal.MaxEntropyInputLength)
+			if len(b) >= 4 {
+				e.lshr(binary.BigEndian.Uint32(b))
+				e.entropySize++
+			}
+		}
+	}
+}
+
+func (e *EntropyPool) GetEntropy(minEntropy int64, minEntropyInputLength int64, maxEntropyInputLength int64) ([]byte, error) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	if minEntropyInputLength < internal.MinEntropyInputLength || maxEntropyInputLength > internal.MaxEntropyInputLength {
+		return nil, internal.ErrEntropyLength
+	}
+
+	entropy := make([]byte, minEntropyInputLength)
+	buf := make([]byte, 4)
+	var i int
+	for i = 0; int64(i) < minEntropyInputLength && e.entropySize > 0; i += 4 {
+		binary.BigEndian.PutUint32(buf, e.pool[e.i])
+		copy(entropy[i:], buf)
+		e.i = (e.i + 1) & 127
+		e.entropySize--
+	}
+	return entropy[:i], nil
+}