github.com/sagernet/gvisor@v0.0.0-20240428053021-e691de28565f/pkg/tcpip/stack/rand.go (about)

     1  // Copyright 2020 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package stack
    16  
    17  import (
    18  	"math/rand"
    19  
    20  	"github.com/sagernet/gvisor/pkg/sync"
    21  )
    22  
    23  // lockedRandomSource provides a threadsafe rand.Source.
    24  type lockedRandomSource struct {
    25  	mu  sync.Mutex
    26  	src rand.Source
    27  }
    28  
    29  func (r *lockedRandomSource) Int63() (n int64) {
    30  	r.mu.Lock()
    31  	n = r.src.Int63()
    32  	r.mu.Unlock()
    33  	return n
    34  }
    35  
    36  func (r *lockedRandomSource) Seed(seed int64) {
    37  	r.mu.Lock()
    38  	r.src.Seed(seed)
    39  	r.mu.Unlock()
    40  }