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server/vendor/github.com/pion/ice/v2/internal/stun/stun.go

@@ -0,0 +1,72 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+// Package stun contains ICE specific STUN code
+package stun
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/pion/stun"
+)
+
+var (
+	errGetXorMappedAddrResponse = errors.New("failed to get XOR-MAPPED-ADDRESS response")
+	errMismatchUsername         = errors.New("username mismatch")
+)
+
+// GetXORMappedAddr initiates a STUN requests to serverAddr using conn, reads the response and returns
+// the XORMappedAddress returned by the STUN server.
+func GetXORMappedAddr(conn net.PacketConn, serverAddr net.Addr, timeout time.Duration) (*stun.XORMappedAddress, error) {
+	if timeout > 0 {
+		if err := conn.SetReadDeadline(time.Now().Add(timeout)); err != nil {
+			return nil, err
+		}
+
+		// Reset timeout after completion
+		defer conn.SetReadDeadline(time.Time{}) //nolint:errcheck
+	}
+
+	req, err := stun.Build(stun.BindingRequest, stun.TransactionID)
+	if err != nil {
+		return nil, err
+	}
+
+	if _, err = conn.WriteTo(req.Raw, serverAddr); err != nil {
+		return nil, err
+	}
+
+	const maxMessageSize = 1280
+	buf := make([]byte, maxMessageSize)
+	n, _, err := conn.ReadFrom(buf)
+	if err != nil {
+		return nil, err
+	}
+
+	res := &stun.Message{Raw: buf[:n]}
+	if err = res.Decode(); err != nil {
+		return nil, err
+	}
+
+	var addr stun.XORMappedAddress
+	if err = addr.GetFrom(res); err != nil {
+		return nil, fmt.Errorf("%w: %v", errGetXorMappedAddrResponse, err) //nolint:errorlint
+	}
+
+	return &addr, nil
+}
+
+// AssertUsername checks that the given STUN message m has a USERNAME attribute with a given value
+func AssertUsername(m *stun.Message, expectedUsername string) error {
+	var username stun.Username
+	if err := username.GetFrom(m); err != nil {
+		return err
+	} else if string(username) != expectedUsername {
+		return fmt.Errorf("%w expected(%x) actual(%x)", errMismatchUsername, expectedUsername, string(username))
+	}
+
+	return nil
+}