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Source file src/net/rawconn_unix_test.go

Documentation: net

  // 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.
  
  // +build darwin dragonfly freebsd linux netbsd openbsd solaris
  
  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
  	}
  	if operr != nil {
  		return n, operr
  	}
  	return n, nil
  }
  
  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
  	}
  	if operr != nil {
  		return operr
  	}
  	return nil
  }
  
  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
  	}
  	if operr != nil {
  		return operr
  	}
  	return nil
  }
  
  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
  	}
  	if operr != nil {
  		return operr
  	}
  	return nil
  }
  

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