// Copyright 2017 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. //go:build unix package net import ( "errors" "syscall" ) func readRawConn(c syscall.RawConn, b []byte) (int, error) { var operr error var n int err := c.Read(func(s uintptr) bool { n, operr = syscall.Read(int(s), b) if operr == syscall.EAGAIN { return false } return true }) if err != nil { return n, err } return n, operr } func writeRawConn(c syscall.RawConn, b []byte) error { var operr error err := c.Write(func(s uintptr) bool { _, operr = syscall.Write(int(s), b) if operr == syscall.EAGAIN { return false } return true }) if err != nil { return err } return operr } func controlRawConn(c syscall.RawConn, addr Addr) error { var operr error fn := func(s uintptr) { _, operr = syscall.GetsockoptInt(int(s), syscall.SOL_SOCKET, syscall.SO_REUSEADDR) if operr != nil { return } switch addr := addr.(type) { case *TCPAddr: // There's no guarantee that IP-level socket // options work well with dual stack sockets. // A simple solution would be to take a look // at the bound address to the raw connection // and to classify the address family of the // underlying socket by the bound address: // // - When IP.To16() != nil and IP.To4() == nil, // we can assume that the raw connection // consists of an IPv6 socket using only // IPv6 addresses. // // - When IP.To16() == nil and IP.To4() != nil, // the raw connection consists of an IPv4 // socket using only IPv4 addresses. // // - Otherwise, the raw connection is a dual // stack socket, an IPv6 socket using IPv6 // addresses including IPv4-mapped or // IPv4-embedded IPv6 addresses. if addr.IP.To16() != nil && addr.IP.To4() == nil { operr = syscall.SetsockoptInt(int(s), syscall.IPPROTO_IPV6, syscall.IPV6_UNICAST_HOPS, 1) } else if addr.IP.To16() == nil && addr.IP.To4() != nil { operr = syscall.SetsockoptInt(int(s), syscall.IPPROTO_IP, syscall.IP_TTL, 1) } } } if err := c.Control(fn); err != nil { return err } return operr } func controlOnConnSetup(network string, address string, c syscall.RawConn) error { var operr error var fn func(uintptr) switch network { case "tcp", "udp", "ip": return errors.New("ambiguous network: " + network) case "unix", "unixpacket", "unixgram": fn = func(s uintptr) { _, operr = syscall.GetsockoptInt(int(s), syscall.SOL_SOCKET, syscall.SO_ERROR) } default: switch network[len(network)-1] { case '4': fn = func(s uintptr) { operr = syscall.SetsockoptInt(int(s), syscall.IPPROTO_IP, syscall.IP_TTL, 1) } case '6': fn = func(s uintptr) { operr = syscall.SetsockoptInt(int(s), syscall.IPPROTO_IPV6, syscall.IPV6_UNICAST_HOPS, 1) } default: return errors.New("unknown network: " + network) } } if err := c.Control(fn); err != nil { return err } return operr }