diff options
Diffstat (limited to 'utils.go')
-rw-r--r-- | utils.go | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/utils.go b/utils.go new file mode 100644 index 0000000..ae7bc41 --- /dev/null +++ b/utils.go @@ -0,0 +1,48 @@ +/* + * Copyright (c) 2014, Yawning Angel <yawning at torproject dot org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +package obfs4 + +import ( + "crypto/rand" + "fmt" + "math/big" +) + +func randRange(min, max int64) (int64, error) { + if max < min { + panic(fmt.Sprintf("randRange: min > max (%d, %d)", min, max)) + } + + r := (max + 1) - min + ret, err := rand.Int(rand.Reader, big.NewInt(r)) + if err != nil { + return 0, err + } + + return ret.Int64() + min, nil +} |