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server/vendor/github.com/pion/ice/v2/rand.go

@@ -0,0 +1,56 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+package ice
+
+import "github.com/pion/randutil"
+
+const (
+	runesAlpha                 = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	runesDigit                 = "0123456789"
+	runesCandidateIDFoundation = runesAlpha + runesDigit + "+/"
+
+	lenUFrag = 16
+	lenPwd   = 32
+)
+
+// Seeding random generator each time limits number of generated sequence to 31-bits,
+// and causes collision on low time accuracy environments.
+// Use global random generator seeded by crypto grade random.
+var (
+	globalMathRandomGenerator  = randutil.NewMathRandomGenerator()               //nolint:gochecknoglobals
+	globalCandidateIDGenerator = candidateIDGenerator{globalMathRandomGenerator} //nolint:gochecknoglobals
+)
+
+// candidateIDGenerator is a random candidate ID generator.
+// Candidate ID is used in SDP and always shared to the other peer.
+// It doesn't require cryptographic random.
+type candidateIDGenerator struct {
+	randutil.MathRandomGenerator
+}
+
+func newCandidateIDGenerator() *candidateIDGenerator {
+	return &candidateIDGenerator{
+		randutil.NewMathRandomGenerator(),
+	}
+}
+
+func (g *candidateIDGenerator) Generate() string {
+	// https://tools.ietf.org/html/rfc5245#section-15.1
+	// candidate-id = "candidate" ":" foundation
+	// foundation   = 1*32ice-char
+	// ice-char     = ALPHA / DIGIT / "+" / "/"
+	return "candidate:" + g.MathRandomGenerator.GenerateString(32, runesCandidateIDFoundation)
+}
+
+// generatePwd generates ICE pwd.
+// This internally uses generateCryptoRandomString.
+func generatePwd() (string, error) {
+	return randutil.GenerateCryptoRandomString(lenPwd, runesAlpha)
+}
+
+// generateUFrag generates ICE user fragment.
+// This internally uses generateCryptoRandomString.
+func generateUFrag() (string, error) {
+	return randutil.GenerateCryptoRandomString(lenUFrag, runesAlpha)
+}